/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include/clang/Sema/Sema.h

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include/clang/Sema/Sema.h
Warning:	line 2191, column 12 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaOverload.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include/clang/Sema -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../include -I /usr/src/gnu/usr.bin/clang/libclangSema/obj -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaOverload.cpp

/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaOverload.cpp

→

1//===--- SemaOverload.cpp - C++ Overloading -------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file provides Sema routines for C++ overloading.
10//
11//===----------------------------------------------------------------------===//

13#include "clang/AST/ASTContext.h"
14#include "clang/AST/CXXInheritance.h"
15#include "clang/AST/DeclObjC.h"
16#include "clang/AST/DependenceFlags.h"
17#include "clang/AST/Expr.h"
18#include "clang/AST/ExprCXX.h"
19#include "clang/AST/ExprObjC.h"
20#include "clang/AST/TypeOrdering.h"
21#include "clang/Basic/Diagnostic.h"
22#include "clang/Basic/DiagnosticOptions.h"
23#include "clang/Basic/PartialDiagnostic.h"
24#include "clang/Basic/SourceManager.h"
25#include "clang/Basic/TargetInfo.h"
26#include "clang/Sema/Initialization.h"
27#include "clang/Sema/Lookup.h"
28#include "clang/Sema/Overload.h"
29#include "clang/Sema/SemaInternal.h"
30#include "clang/Sema/Template.h"
31#include "clang/Sema/TemplateDeduction.h"
32#include "llvm/ADT/DenseSet.h"
33#include "llvm/ADT/Optional.h"
34#include "llvm/ADT/STLExtras.h"
35#include "llvm/ADT/SmallPtrSet.h"
36#include "llvm/ADT/SmallString.h"
37#include <algorithm>
38#include <cstdlib>

40using namespace clang;
41using namespace sema;

43using AllowedExplicit = Sema::AllowedExplicit;

45static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) {
return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) {
  return P->hasAttr<PassObjectSizeAttr>();
});
49}

51/// A convenience routine for creating a decayed reference to a function.
52static ExprResult
53CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl,
                    const Expr *Base, bool HadMultipleCandidates,
                    SourceLocation Loc = SourceLocation(),
                    const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){
if (S.DiagnoseUseOfDecl(FoundDecl, Loc))
  return ExprError();
// If FoundDecl is different from Fn (such as if one is a template
// and the other a specialization), make sure DiagnoseUseOfDecl is
// called on both.
// FIXME: This would be more comprehensively addressed by modifying
// DiagnoseUseOfDecl to accept both the FoundDecl and the decl
// being used.
if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc))
  return ExprError();
DeclRefExpr *DRE = new (S.Context)
    DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo);
if (HadMultipleCandidates)
  DRE->setHadMultipleCandidates(true);

S.MarkDeclRefReferenced(DRE, Base);
if (auto *FPT = DRE->getType()->getAs<FunctionProtoType>()) {
  if (isUnresolvedExceptionSpec(FPT->getExceptionSpecType())) {
    S.ResolveExceptionSpec(Loc, FPT);
    DRE->setType(Fn->getType());
  }
}
return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()),
                           CK_FunctionToPointerDecay);
81}

83static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
                               bool InOverloadResolution,
                               StandardConversionSequence &SCS,
                               bool CStyle,
                               bool AllowObjCWritebackConversion);

89static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From,
                                               QualType &ToType,
                                               bool InOverloadResolution,
                                               StandardConversionSequence &SCS,
                                               bool CStyle);
94static OverloadingResult
95IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
                      UserDefinedConversionSequence& User,
                      OverloadCandidateSet& Conversions,
                      AllowedExplicit AllowExplicit,
                      bool AllowObjCConversionOnExplicit);

101static ImplicitConversionSequence::CompareKind
102CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
                                 const StandardConversionSequence& SCS1,
                                 const StandardConversionSequence& SCS2);

106static ImplicitConversionSequence::CompareKind
107CompareQualificationConversions(Sema &S,
                              const StandardConversionSequence& SCS1,
                              const StandardConversionSequence& SCS2);

111static ImplicitConversionSequence::CompareKind
112CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
                              const StandardConversionSequence& SCS1,
                              const StandardConversionSequence& SCS2);

116/// GetConversionRank - Retrieve the implicit conversion rank
117/// corresponding to the given implicit conversion kind.
118ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) {
static const ImplicitConversionRank
  Rank[(int)ICK_Num_Conversion_Kinds] = {
  ICR_Exact_Match,
  ICR_Exact_Match,
  ICR_Exact_Match,
  ICR_Exact_Match,
  ICR_Exact_Match,
  ICR_Exact_Match,
  ICR_Promotion,
  ICR_Promotion,
  ICR_Promotion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_OCL_Scalar_Widening,
  ICR_Complex_Real_Conversion,
  ICR_Conversion,
  ICR_Conversion,
  ICR_Writeback_Conversion,
  ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
                   // it was omitted by the patch that added
                   // ICK_Zero_Event_Conversion
  ICR_C_Conversion,
  ICR_C_Conversion_Extension
};
return Rank[(int)Kind];
153}

155/// GetImplicitConversionName - Return the name of this kind of
156/// implicit conversion.
157static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
  "No conversion",
  "Lvalue-to-rvalue",
  "Array-to-pointer",
  "Function-to-pointer",
  "Function pointer conversion",
  "Qualification",
  "Integral promotion",
  "Floating point promotion",
  "Complex promotion",
  "Integral conversion",
  "Floating conversion",
  "Complex conversion",
  "Floating-integral conversion",
  "Pointer conversion",
  "Pointer-to-member conversion",
  "Boolean conversion",
  "Compatible-types conversion",
  "Derived-to-base conversion",
  "Vector conversion",
  "SVE Vector conversion",
  "Vector splat",
  "Complex-real conversion",
  "Block Pointer conversion",
  "Transparent Union Conversion",
  "Writeback conversion",
  "OpenCL Zero Event Conversion",
  "C specific type conversion",
  "Incompatible pointer conversion"
};
return Name[Kind];
189}

191/// StandardConversionSequence - Set the standard conversion
192/// sequence to the identity conversion.
193void StandardConversionSequence::setAsIdentityConversion() {
First = ICK_Identity;
Second = ICK_Identity;
Third = ICK_Identity;
DeprecatedStringLiteralToCharPtr = false;
QualificationIncludesObjCLifetime = false;
ReferenceBinding = false;
DirectBinding = false;
IsLvalueReference = true;
BindsToFunctionLvalue = false;
BindsToRvalue = false;
BindsImplicitObjectArgumentWithoutRefQualifier = false;
ObjCLifetimeConversionBinding = false;
CopyConstructor = nullptr;
207}

209/// getRank - Retrieve the rank of this standard conversion sequence
210/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
211/// implicit conversions.
212ImplicitConversionRank StandardConversionSequence::getRank() const {
ImplicitConversionRank Rank = ICR_Exact_Match;
if  (GetConversionRank(First) > Rank)
  Rank = GetConversionRank(First);
if  (GetConversionRank(Second) > Rank)
  Rank = GetConversionRank(Second);
if  (GetConversionRank(Third) > Rank)
  Rank = GetConversionRank(Third);
return Rank;
221}

223/// isPointerConversionToBool - Determines whether this conversion is
224/// a conversion of a pointer or pointer-to-member to bool. This is
225/// used as part of the ranking of standard conversion sequences
226/// (C++ 13.3.3.2p4).
227bool StandardConversionSequence::isPointerConversionToBool() const {
// Note that FromType has not necessarily been transformed by the
// array-to-pointer or function-to-pointer implicit conversions, so
// check for their presence as well as checking whether FromType is
// a pointer.
if (getToType(1)->isBooleanType() &&
    (getFromType()->isPointerType() ||
     getFromType()->isMemberPointerType() ||
     getFromType()->isObjCObjectPointerType() ||
     getFromType()->isBlockPointerType() ||
     First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
  return true;

return false;
241}

243/// isPointerConversionToVoidPointer - Determines whether this
244/// conversion is a conversion of a pointer to a void pointer. This is
245/// used as part of the ranking of standard conversion sequences (C++
246/// 13.3.3.2p4).
247bool
248StandardConversionSequence::
249isPointerConversionToVoidPointer(ASTContext& Context) const {
QualType FromType = getFromType();
QualType ToType = getToType(1);

// Note that FromType has not necessarily been transformed by the
// array-to-pointer implicit conversion, so check for its presence
// and redo the conversion to get a pointer.
if (First == ICK_Array_To_Pointer)
  FromType = Context.getArrayDecayedType(FromType);

if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
  if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
    return ToPtrType->getPointeeType()->isVoidType();

return false;
264}

266/// Skip any implicit casts which could be either part of a narrowing conversion
267/// or after one in an implicit conversion.
268static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx,
                                           const Expr *Converted) {
// We can have cleanups wrapping the converted expression; these need to be
// preserved so that destructors run if necessary.
if (auto *EWC = dyn_cast<ExprWithCleanups>(Converted)) {
  Expr *Inner =
      const_cast<Expr *>(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr()));
  return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(),
                                  EWC->getObjects());
}

while (auto *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
  switch (ICE->getCastKind()) {
  case CK_NoOp:
  case CK_IntegralCast:
  case CK_IntegralToBoolean:
  case CK_IntegralToFloating:
  case CK_BooleanToSignedIntegral:
  case CK_FloatingToIntegral:
  case CK_FloatingToBoolean:
  case CK_FloatingCast:
    Converted = ICE->getSubExpr();
    continue;

  default:
    return Converted;
  }
}

return Converted;
298}

300/// Check if this standard conversion sequence represents a narrowing
301/// conversion, according to C++11 [dcl.init.list]p7.
302///
303/// \param Ctx  The AST context.
304/// \param Converted  The result of applying this standard conversion sequence.
305/// \param ConstantValue  If this is an NK_Constant_Narrowing conversion, the
306///        value of the expression prior to the narrowing conversion.
307/// \param ConstantType  If this is an NK_Constant_Narrowing conversion, the
308///        type of the expression prior to the narrowing conversion.
309/// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
310///        from floating point types to integral types should be ignored.
311NarrowingKind StandardConversionSequence::getNarrowingKind(
  ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
  QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++")((void)0);

// C++11 [dcl.init.list]p7:
//   A narrowing conversion is an implicit conversion ...
QualType FromType = getToType(0);
QualType ToType = getToType(1);

// A conversion to an enumeration type is narrowing if the conversion to
// the underlying type is narrowing. This only arises for expressions of
// the form 'Enum{init}'.
if (auto *ET = ToType->getAs<EnumType>())
  ToType = ET->getDecl()->getIntegerType();

switch (Second) {
// 'bool' is an integral type; dispatch to the right place to handle it.
case ICK_Boolean_Conversion:
  if (FromType->isRealFloatingType())
    goto FloatingIntegralConversion;
  if (FromType->isIntegralOrUnscopedEnumerationType())
    goto IntegralConversion;
  // -- from a pointer type or pointer-to-member type to bool, or
  return NK_Type_Narrowing;

// -- from a floating-point type to an integer type, or
//
// -- from an integer type or unscoped enumeration type to a floating-point
//    type, except where the source is a constant expression and the actual
//    value after conversion will fit into the target type and will produce
//    the original value when converted back to the original type, or
case ICK_Floating_Integral:
FloatingIntegralConversion:
  if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
    return NK_Type_Narrowing;
  } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
             ToType->isRealFloatingType()) {
    if (IgnoreFloatToIntegralConversion)
      return NK_Not_Narrowing;
    const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
    assert(Initializer && "Unknown conversion expression")((void)0);

    // If it's value-dependent, we can't tell whether it's narrowing.
    if (Initializer->isValueDependent())
      return NK_Dependent_Narrowing;

    if (Optional<llvm::APSInt> IntConstantValue =
            Initializer->getIntegerConstantExpr(Ctx)) {
      // Convert the integer to the floating type.
      llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
      Result.convertFromAPInt(*IntConstantValue, IntConstantValue->isSigned(),
                              llvm::APFloat::rmNearestTiesToEven);
      // And back.
      llvm::APSInt ConvertedValue = *IntConstantValue;
      bool ignored;
      Result.convertToInteger(ConvertedValue,
                              llvm::APFloat::rmTowardZero, &ignored);
      // If the resulting value is different, this was a narrowing conversion.
      if (*IntConstantValue != ConvertedValue) {
        ConstantValue = APValue(*IntConstantValue);
        ConstantType = Initializer->getType();
        return NK_Constant_Narrowing;
      }
    } else {
      // Variables are always narrowings.
      return NK_Variable_Narrowing;
    }
  }
  return NK_Not_Narrowing;

// -- from long double to double or float, or from double to float, except
//    where the source is a constant expression and the actual value after
//    conversion is within the range of values that can be represented (even
//    if it cannot be represented exactly), or
case ICK_Floating_Conversion:
  if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
      Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
    // FromType is larger than ToType.
    const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);

    // If it's value-dependent, we can't tell whether it's narrowing.
    if (Initializer->isValueDependent())
      return NK_Dependent_Narrowing;

    if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
      // Constant!
      assert(ConstantValue.isFloat())((void)0);
      llvm::APFloat FloatVal = ConstantValue.getFloat();
      // Convert the source value into the target type.
      bool ignored;
      llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
        Ctx.getFloatTypeSemantics(ToType),
        llvm::APFloat::rmNearestTiesToEven, &ignored);
      // If there was no overflow, the source value is within the range of
      // values that can be represented.
      if (ConvertStatus & llvm::APFloat::opOverflow) {
        ConstantType = Initializer->getType();
        return NK_Constant_Narrowing;
      }
    } else {
      return NK_Variable_Narrowing;
    }
  }
  return NK_Not_Narrowing;

// -- from an integer type or unscoped enumeration type to an integer type
//    that cannot represent all the values of the original type, except where
//    the source is a constant expression and the actual value after
//    conversion will fit into the target type and will produce the original
//    value when converted back to the original type.
case ICK_Integral_Conversion:
IntegralConversion: {
  assert(FromType->isIntegralOrUnscopedEnumerationType())((void)0);
  assert(ToType->isIntegralOrUnscopedEnumerationType())((void)0);
  const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
  const unsigned FromWidth = Ctx.getIntWidth(FromType);
  const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
  const unsigned ToWidth = Ctx.getIntWidth(ToType);

  if (FromWidth > ToWidth ||
      (FromWidth == ToWidth && FromSigned != ToSigned) ||
      (FromSigned && !ToSigned)) {
    // Not all values of FromType can be represented in ToType.
    const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);

    // If it's value-dependent, we can't tell whether it's narrowing.
    if (Initializer->isValueDependent())
      return NK_Dependent_Narrowing;

    Optional<llvm::APSInt> OptInitializerValue;
    if (!(OptInitializerValue = Initializer->getIntegerConstantExpr(Ctx))) {
      // Such conversions on variables are always narrowing.
      return NK_Variable_Narrowing;
    }
    llvm::APSInt &InitializerValue = *OptInitializerValue;
    bool Narrowing = false;
    if (FromWidth < ToWidth) {
      // Negative -> unsigned is narrowing. Otherwise, more bits is never
      // narrowing.
      if (InitializerValue.isSigned() && InitializerValue.isNegative())
        Narrowing = true;
    } else {
      // Add a bit to the InitializerValue so we don't have to worry about
      // signed vs. unsigned comparisons.
      InitializerValue = InitializerValue.extend(
        InitializerValue.getBitWidth() + 1);
      // Convert the initializer to and from the target width and signed-ness.
      llvm::APSInt ConvertedValue = InitializerValue;
      ConvertedValue = ConvertedValue.trunc(ToWidth);
      ConvertedValue.setIsSigned(ToSigned);
      ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
      ConvertedValue.setIsSigned(InitializerValue.isSigned());
      // If the result is different, this was a narrowing conversion.
      if (ConvertedValue != InitializerValue)
        Narrowing = true;
    }
    if (Narrowing) {
      ConstantType = Initializer->getType();
      ConstantValue = APValue(InitializerValue);
      return NK_Constant_Narrowing;
    }
  }
  return NK_Not_Narrowing;
}

default:
  // Other kinds of conversions are not narrowings.
  return NK_Not_Narrowing;
}
481}

483/// dump - Print this standard conversion sequence to standard
484/// error. Useful for debugging overloading issues.
485LLVM_DUMP_METHOD__attribute__((noinline)) void StandardConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
bool PrintedSomething = false;
if (First != ICK_Identity) {
  OS << GetImplicitConversionName(First);
  PrintedSomething = true;
}

if (Second != ICK_Identity) {
  if (PrintedSomething) {
    OS << " -> ";
  }
  OS << GetImplicitConversionName(Second);

  if (CopyConstructor) {
    OS << " (by copy constructor)";
  } else if (DirectBinding) {
    OS << " (direct reference binding)";
  } else if (ReferenceBinding) {
    OS << " (reference binding)";
  }
  PrintedSomething = true;
}

if (Third != ICK_Identity) {
  if (PrintedSomething) {
    OS << " -> ";
  }
  OS << GetImplicitConversionName(Third);
  PrintedSomething = true;
}

if (!PrintedSomething) {
  OS << "No conversions required";
}
520}

522/// dump - Print this user-defined conversion sequence to standard
523/// error. Useful for debugging overloading issues.
524void UserDefinedConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
if (Before.First || Before.Second || Before.Third) {
  Before.dump();
  OS << " -> ";
}
if (ConversionFunction)
  OS << '\'' << *ConversionFunction << '\'';
else
  OS << "aggregate initialization";
if (After.First || After.Second || After.Third) {
  OS << " -> ";
  After.dump();
}
538}

540/// dump - Print this implicit conversion sequence to standard
541/// error. Useful for debugging overloading issues.
542void ImplicitConversionSequence::dump() const {
raw_ostream &OS = llvm::errs();
if (isStdInitializerListElement())
  OS << "Worst std::initializer_list element conversion: ";
switch (ConversionKind) {
case StandardConversion:
  OS << "Standard conversion: ";
  Standard.dump();
  break;
case UserDefinedConversion:
  OS << "User-defined conversion: ";
  UserDefined.dump();
  break;
case EllipsisConversion:
  OS << "Ellipsis conversion";
  break;
case AmbiguousConversion:
  OS << "Ambiguous conversion";
  break;
case BadConversion:
  OS << "Bad conversion";
  break;
}

OS << "\n";
567}

569void AmbiguousConversionSequence::construct() {
new (&conversions()) ConversionSet();
571}

573void AmbiguousConversionSequence::destruct() {
conversions().~ConversionSet();
575}

577void
578AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
FromTypePtr = O.FromTypePtr;
ToTypePtr = O.ToTypePtr;
new (&conversions()) ConversionSet(O.conversions());
582}

584namespace {
// Structure used by DeductionFailureInfo to store
// template argument information.
struct DFIArguments {
  TemplateArgument FirstArg;
  TemplateArgument SecondArg;
};
// Structure used by DeductionFailureInfo to store
// template parameter and template argument information.
struct DFIParamWithArguments : DFIArguments {
  TemplateParameter Param;
};
// Structure used by DeductionFailureInfo to store template argument
// information and the index of the problematic call argument.
struct DFIDeducedMismatchArgs : DFIArguments {
  TemplateArgumentList *TemplateArgs;
  unsigned CallArgIndex;
};
// Structure used by DeductionFailureInfo to store information about
// unsatisfied constraints.
struct CNSInfo {
  TemplateArgumentList *TemplateArgs;
  ConstraintSatisfaction Satisfaction;
};
608}

610/// Convert from Sema's representation of template deduction information
611/// to the form used in overload-candidate information.
612DeductionFailureInfo
613clang::MakeDeductionFailureInfo(ASTContext &Context,
                              Sema::TemplateDeductionResult TDK,
                              TemplateDeductionInfo &Info) {
DeductionFailureInfo Result;
Result.Result = static_cast<unsigned>(TDK);
Result.HasDiagnostic = false;
switch (TDK) {
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_MiscellaneousDeductionFailure:
case Sema::TDK_CUDATargetMismatch:
  Result.Data = nullptr;
  break;

case Sema::TDK_Incomplete:
case Sema::TDK_InvalidExplicitArguments:
  Result.Data = Info.Param.getOpaqueValue();
  break;

case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested: {
  // FIXME: Should allocate from normal heap so that we can free this later.
  auto *Saved = new (Context) DFIDeducedMismatchArgs;
  Saved->FirstArg = Info.FirstArg;
  Saved->SecondArg = Info.SecondArg;
  Saved->TemplateArgs = Info.take();
  Saved->CallArgIndex = Info.CallArgIndex;
  Result.Data = Saved;
  break;
}

case Sema::TDK_NonDeducedMismatch: {
  // FIXME: Should allocate from normal heap so that we can free this later.
  DFIArguments *Saved = new (Context) DFIArguments;
  Saved->FirstArg = Info.FirstArg;
  Saved->SecondArg = Info.SecondArg;
  Result.Data = Saved;
  break;
}

case Sema::TDK_IncompletePack:
  // FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified: {
  // FIXME: Should allocate from normal heap so that we can free this later.
  DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
  Saved->Param = Info.Param;
  Saved->FirstArg = Info.FirstArg;
  Saved->SecondArg = Info.SecondArg;
  Result.Data = Saved;
  break;
}

case Sema::TDK_SubstitutionFailure:
  Result.Data = Info.take();
  if (Info.hasSFINAEDiagnostic()) {
    PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
        SourceLocation(), PartialDiagnostic::NullDiagnostic());
    Info.takeSFINAEDiagnostic(*Diag);
    Result.HasDiagnostic = true;
  }
  break;

case Sema::TDK_ConstraintsNotSatisfied: {
  CNSInfo *Saved = new (Context) CNSInfo;
  Saved->TemplateArgs = Info.take();
  Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
  Result.Data = Saved;
  break;
}

case Sema::TDK_Success:
case Sema::TDK_NonDependentConversionFailure:
  llvm_unreachable("not a deduction failure")__builtin_unreachable();
}

return Result;
692}

694void DeductionFailureInfo::Destroy() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
  break;

case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
  // FIXME: Destroy the data?
  Data = nullptr;
  break;

case Sema::TDK_SubstitutionFailure:
  // FIXME: Destroy the template argument list?
  Data = nullptr;
  if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
    Diag->~PartialDiagnosticAt();
    HasDiagnostic = false;
  }
  break;

case Sema::TDK_ConstraintsNotSatisfied:
  // FIXME: Destroy the template argument list?
  Data = nullptr;
  if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
    Diag->~PartialDiagnosticAt();
    HasDiagnostic = false;
  }
  break;

// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
  break;
}
739}

741PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
if (HasDiagnostic)
  return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
return nullptr;
745}

747TemplateParameter DeductionFailureInfo::getTemplateParameter() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
  return TemplateParameter();

case Sema::TDK_Incomplete:
case Sema::TDK_InvalidExplicitArguments:
  return TemplateParameter::getFromOpaqueValue(Data);

case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
  return static_cast<DFIParamWithArguments*>(Data)->Param;

// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
  break;
}

return TemplateParameter();
778}

780TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
  return nullptr;

case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
  return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;

case Sema::TDK_SubstitutionFailure:
  return static_cast<TemplateArgumentList*>(Data);

case Sema::TDK_ConstraintsNotSatisfied:
  return static_cast<CNSInfo*>(Data)->TemplateArgs;

// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
  break;
}

return nullptr;
813}

815const TemplateArgument *DeductionFailureInfo::getFirstArg() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
  return nullptr;

case Sema::TDK_IncompletePack:
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
  return &static_cast<DFIArguments*>(Data)->FirstArg;

// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
  break;
}

return nullptr;
844}

846const TemplateArgument *DeductionFailureInfo::getSecondArg() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_Success:
case Sema::TDK_Invalid:
case Sema::TDK_InstantiationDepth:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_CUDATargetMismatch:
case Sema::TDK_NonDependentConversionFailure:
case Sema::TDK_ConstraintsNotSatisfied:
  return nullptr;

case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
  return &static_cast<DFIArguments*>(Data)->SecondArg;

// Unhandled
case Sema::TDK_MiscellaneousDeductionFailure:
  break;
}

return nullptr;
875}

877llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested:
  return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;

default:
  return llvm::None;
}
886}

888bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
  OverloadedOperatorKind Op) {
if (!AllowRewrittenCandidates)
  return false;
return Op == OO_EqualEqual || Op == OO_Spaceship;
893}

895bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
  ASTContext &Ctx, const FunctionDecl *FD) {
if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator()))
  return false;
// Don't bother adding a reversed candidate that can never be a better
// match than the non-reversed version.
return FD->getNumParams() != 2 ||
       !Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(),
                                   FD->getParamDecl(1)->getType()) ||
       FD->hasAttr<EnableIfAttr>();
905}

907void OverloadCandidateSet::destroyCandidates() {
for (iterator i = begin(), e = end(); i != e; ++i) {
  for (auto &C : i->Conversions)
    C.~ImplicitConversionSequence();
  if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
    i->DeductionFailure.Destroy();
}
914}

916void OverloadCandidateSet::clear(CandidateSetKind CSK) {
destroyCandidates();
SlabAllocator.Reset();
NumInlineBytesUsed = 0;
Candidates.clear();
Functions.clear();
Kind = CSK;
923}

925namespace {
class UnbridgedCastsSet {
  struct Entry {
    Expr **Addr;
    Expr *Saved;
  };
  SmallVector<Entry, 2> Entries;

public:
  void save(Sema &S, Expr *&E) {
    assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast))((void)0);
    Entry entry = { &E, E };
    Entries.push_back(entry);
    E = S.stripARCUnbridgedCast(E);
  }

  void restore() {
    for (SmallVectorImpl<Entry>::iterator
           i = Entries.begin(), e = Entries.end(); i != e; ++i)
      *i->Addr = i->Saved;
  }
};
947}

949/// checkPlaceholderForOverload - Do any interesting placeholder-like
950/// preprocessing on the given expression.
951///
952/// \param unbridgedCasts a collection to which to add unbridged casts;
953///   without this, they will be immediately diagnosed as errors
954///
955/// Return true on unrecoverable error.
956static bool
957checkPlaceholderForOverload(Sema &S, Expr *&E,
                          UnbridgedCastsSet *unbridgedCasts = nullptr) {
if (const BuiltinType *placeholder =  E->getType()->getAsPlaceholderType()) {
  // We can't handle overloaded expressions here because overload
  // resolution might reasonably tweak them.
  if (placeholder->getKind() == BuiltinType::Overload) return false;

  // If the context potentially accepts unbridged ARC casts, strip
  // the unbridged cast and add it to the collection for later restoration.
  if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
      unbridgedCasts) {
    unbridgedCasts->save(S, E);
    return false;
  }

  // Go ahead and check everything else.
  ExprResult result = S.CheckPlaceholderExpr(E);
  if (result.isInvalid())
    return true;

  E = result.get();
  return false;
}

// Nothing to do.
return false;
983}

985/// checkArgPlaceholdersForOverload - Check a set of call operands for
986/// placeholders.
987static bool checkArgPlaceholdersForOverload(Sema &S,
                                          MultiExprArg Args,
                                          UnbridgedCastsSet &unbridged) {
for (unsigned i = 0, e = Args.size(); i != e; ++i)
  if (checkPlaceholderForOverload(S, Args[i], &unbridged))
    return true;

return false;
995}

997/// Determine whether the given New declaration is an overload of the
998/// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
999/// New and Old cannot be overloaded, e.g., if New has the same signature as
1000/// some function in Old (C++ 1.3.10) or if the Old declarations aren't
1001/// functions (or function templates) at all. When it does return Ovl_Match or
1002/// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
1003/// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
1004/// declaration.
1005///
1006/// Example: Given the following input:
1007///
1008///   void f(int, float); // #1
1009///   void f(int, int); // #2
1010///   int f(int, int); // #3
1011///
1012/// When we process #1, there is no previous declaration of "f", so IsOverload
1013/// will not be used.
1014///
1015/// When we process #2, Old contains only the FunctionDecl for #1. By comparing
1016/// the parameter types, we see that #1 and #2 are overloaded (since they have
1017/// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
1018/// unchanged.
1019///
1020/// When we process #3, Old is an overload set containing #1 and #2. We compare
1021/// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
1022/// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
1023/// functions are not part of the signature), IsOverload returns Ovl_Match and
1024/// MatchedDecl will be set to point to the FunctionDecl for #2.
1025///
1026/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
1027/// by a using declaration. The rules for whether to hide shadow declarations
1028/// ignore some properties which otherwise figure into a function template's
1029/// signature.
1030Sema::OverloadKind
1031Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
                  NamedDecl *&Match, bool NewIsUsingDecl) {
for (LookupResult::iterator I = Old.begin(), E = Old.end();
       I != E; ++I) {
  NamedDecl *OldD = *I;

  bool OldIsUsingDecl = false;
  if (isa<UsingShadowDecl>(OldD)) {
    OldIsUsingDecl = true;

    // We can always introduce two using declarations into the same
    // context, even if they have identical signatures.
    if (NewIsUsingDecl) continue;

    OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
  }

  // A using-declaration does not conflict with another declaration
  // if one of them is hidden.
  if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
    continue;

  // If either declaration was introduced by a using declaration,
  // we'll need to use slightly different rules for matching.
  // Essentially, these rules are the normal rules, except that
  // function templates hide function templates with different
  // return types or template parameter lists.
  bool UseMemberUsingDeclRules =
    (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
    !New->getFriendObjectKind();

  if (FunctionDecl *OldF = OldD->getAsFunction()) {
    if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
      if (UseMemberUsingDeclRules && OldIsUsingDecl) {
        HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
        continue;
      }

      if (!isa<FunctionTemplateDecl>(OldD) &&
          !shouldLinkPossiblyHiddenDecl(*I, New))
        continue;

      Match = *I;
      return Ovl_Match;
    }

    // Builtins that have custom typechecking or have a reference should
    // not be overloadable or redeclarable.
    if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
      Match = *I;
      return Ovl_NonFunction;
    }
  } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
    // We can overload with these, which can show up when doing
    // redeclaration checks for UsingDecls.
    assert(Old.getLookupKind() == LookupUsingDeclName)((void)0);
  } else if (isa<TagDecl>(OldD)) {
    // We can always overload with tags by hiding them.
  } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
    // Optimistically assume that an unresolved using decl will
    // overload; if it doesn't, we'll have to diagnose during
    // template instantiation.
    //
    // Exception: if the scope is dependent and this is not a class
    // member, the using declaration can only introduce an enumerator.
    if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
      Match = *I;
      return Ovl_NonFunction;
    }
  } else {
    // (C++ 13p1):
    //   Only function declarations can be overloaded; object and type
    //   declarations cannot be overloaded.
    Match = *I;
    return Ovl_NonFunction;
  }
}

// C++ [temp.friend]p1:
//   For a friend function declaration that is not a template declaration:
//    -- if the name of the friend is a qualified or unqualified template-id,
//       [...], otherwise
//    -- if the name of the friend is a qualified-id and a matching
//       non-template function is found in the specified class or namespace,
//       the friend declaration refers to that function, otherwise,
//    -- if the name of the friend is a qualified-id and a matching function
//       template is found in the specified class or namespace, the friend
//       declaration refers to the deduced specialization of that function
//       template, otherwise
//    -- the name shall be an unqualified-id [...]
// If we get here for a qualified friend declaration, we've just reached the
// third bullet. If the type of the friend is dependent, skip this lookup
// until instantiation.
if (New->getFriendObjectKind() && New->getQualifier() &&
    !New->getDescribedFunctionTemplate() &&
    !New->getDependentSpecializationInfo() &&
    !New->getType()->isDependentType()) {
  LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
  TemplateSpecResult.addAllDecls(Old);
  if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
                                          /*QualifiedFriend*/true)) {
    New->setInvalidDecl();
    return Ovl_Overload;
  }

  Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
  return Ovl_Match;
}

return Ovl_Overload;
1141}

1143bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
                    bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs,
                    bool ConsiderRequiresClauses) {
// C++ [basic.start.main]p2: This function shall not be overloaded.
if (New->isMain())
  return false;

// MSVCRT user defined entry points cannot be overloaded.
if (New->isMSVCRTEntryPoint())
  return false;

FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();

// C++ [temp.fct]p2:
//   A function template can be overloaded with other function templates
//   and with normal (non-template) functions.
if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
  return true;

// Is the function New an overload of the function Old?
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());

// Compare the signatures (C++ 1.3.10) of the two functions to
// determine whether they are overloads. If we find any mismatch
// in the signature, they are overloads.

// If either of these functions is a K&R-style function (no
// prototype), then we consider them to have matching signatures.
if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
    isa<FunctionNoProtoType>(NewQType.getTypePtr()))
  return false;

const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);

// The signature of a function includes the types of its
// parameters (C++ 1.3.10), which includes the presence or absence
// of the ellipsis; see C++ DR 357).
if (OldQType != NewQType &&
    (OldType->getNumParams() != NewType->getNumParams() ||
     OldType->isVariadic() != NewType->isVariadic() ||
     !FunctionParamTypesAreEqual(OldType, NewType)))
  return true;

// C++ [temp.over.link]p4:
//   The signature of a function template consists of its function
//   signature, its return type and its template parameter list. The names
//   of the template parameters are significant only for establishing the
//   relationship between the template parameters and the rest of the
//   signature.
//
// We check the return type and template parameter lists for function
// templates first; the remaining checks follow.
//
// However, we don't consider either of these when deciding whether
// a member introduced by a shadow declaration is hidden.
if (!UseMemberUsingDeclRules && NewTemplate &&
    (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
                                     OldTemplate->getTemplateParameters(),
                                     false, TPL_TemplateMatch) ||
     !Context.hasSameType(Old->getDeclaredReturnType(),
                          New->getDeclaredReturnType())))
  return true;

// If the function is a class member, its signature includes the
// cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
//
// As part of this, also check whether one of the member functions
// is static, in which case they are not overloads (C++
// 13.1p2). While not part of the definition of the signature,
// this check is important to determine whether these functions
// can be overloaded.
CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
if (OldMethod && NewMethod &&
    !OldMethod->isStatic() && !NewMethod->isStatic()) {
  if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
    if (!UseMemberUsingDeclRules &&
        (OldMethod->getRefQualifier() == RQ_None ||
         NewMethod->getRefQualifier() == RQ_None)) {
      // C++0x [over.load]p2:
      //   - Member function declarations with the same name and the same
      //     parameter-type-list as well as member function template
      //     declarations with the same name, the same parameter-type-list, and
      //     the same template parameter lists cannot be overloaded if any of
      //     them, but not all, have a ref-qualifier (8.3.5).
      Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
        << NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
      Diag(OldMethod->getLocation(), diag::note_previous_declaration);
    }
    return true;
  }

  // We may not have applied the implicit const for a constexpr member
  // function yet (because we haven't yet resolved whether this is a static
  // or non-static member function). Add it now, on the assumption that this
  // is a redeclaration of OldMethod.
  auto OldQuals = OldMethod->getMethodQualifiers();
  auto NewQuals = NewMethod->getMethodQualifiers();
  if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
      !isa<CXXConstructorDecl>(NewMethod))
    NewQuals.addConst();
  // We do not allow overloading based off of '__restrict'.
  OldQuals.removeRestrict();
  NewQuals.removeRestrict();
  if (OldQuals != NewQuals)
    return true;
}

// Though pass_object_size is placed on parameters and takes an argument, we
// consider it to be a function-level modifier for the sake of function
// identity. Either the function has one or more parameters with
// pass_object_size or it doesn't.
if (functionHasPassObjectSizeParams(New) !=
    functionHasPassObjectSizeParams(Old))
  return true;

// enable_if attributes are an order-sensitive part of the signature.
for (specific_attr_iterator<EnableIfAttr>
       NewI = New->specific_attr_begin<EnableIfAttr>(),
       NewE = New->specific_attr_end<EnableIfAttr>(),
       OldI = Old->specific_attr_begin<EnableIfAttr>(),
       OldE = Old->specific_attr_end<EnableIfAttr>();
     NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
  if (NewI == NewE || OldI == OldE)
    return true;
  llvm::FoldingSetNodeID NewID, OldID;
  NewI->getCond()->Profile(NewID, Context, true);
  OldI->getCond()->Profile(OldID, Context, true);
  if (NewID != OldID)
    return true;
}

if (getLangOpts().CUDA && ConsiderCudaAttrs) {
  // Don't allow overloading of destructors.  (In theory we could, but it
  // would be a giant change to clang.)
  if (!isa<CXXDestructorDecl>(New)) {
    CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
                       OldTarget = IdentifyCUDATarget(Old);
    if (NewTarget != CFT_InvalidTarget) {
      assert((OldTarget != CFT_InvalidTarget) &&((void)0)
             "Unexpected invalid target.")((void)0);

      // Allow overloading of functions with same signature and different CUDA
      // target attributes.
      if (NewTarget != OldTarget)
        return true;
    }
  }
}

if (ConsiderRequiresClauses) {
  Expr *NewRC = New->getTrailingRequiresClause(),
       *OldRC = Old->getTrailingRequiresClause();
  if ((NewRC != nullptr) != (OldRC != nullptr))
    // RC are most certainly different - these are overloads.
    return true;

  if (NewRC) {
    llvm::FoldingSetNodeID NewID, OldID;
    NewRC->Profile(NewID, Context, /*Canonical=*/true);
    OldRC->Profile(OldID, Context, /*Canonical=*/true);
    if (NewID != OldID)
      // RCs are not equivalent - these are overloads.
      return true;
  }
}

// The signatures match; this is not an overload.
return false;
1315}

1317/// Tries a user-defined conversion from From to ToType.
1318///
1319/// Produces an implicit conversion sequence for when a standard conversion
1320/// is not an option. See TryImplicitConversion for more information.
1321static ImplicitConversionSequence
1322TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
                       bool SuppressUserConversions,
                       AllowedExplicit AllowExplicit,
                       bool InOverloadResolution,
                       bool CStyle,
                       bool AllowObjCWritebackConversion,
                       bool AllowObjCConversionOnExplicit) {
ImplicitConversionSequence ICS;

if (SuppressUserConversions) {
  // We're not in the case above, so there is no conversion that
  // we can perform.
  ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
  return ICS;
}

// Attempt user-defined conversion.
OverloadCandidateSet Conversions(From->getExprLoc(),
                                 OverloadCandidateSet::CSK_Normal);
switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
                                Conversions, AllowExplicit,
                                AllowObjCConversionOnExplicit)) {
case OR_Success:
case OR_Deleted:
  ICS.setUserDefined();
  // C++ [over.ics.user]p4:
  //   A conversion of an expression of class type to the same class
  //   type is given Exact Match rank, and a conversion of an
  //   expression of class type to a base class of that type is
  //   given Conversion rank, in spite of the fact that a copy
  //   constructor (i.e., a user-defined conversion function) is
  //   called for those cases.
  if (CXXConstructorDecl *Constructor
        = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
    QualType FromCanon
      = S.Context.getCanonicalType(From->getType().getUnqualifiedType());
    QualType ToCanon
      = S.Context.getCanonicalType(ToType).getUnqualifiedType();
    if (Constructor->isCopyConstructor() &&
        (FromCanon == ToCanon ||
         S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
      // Turn this into a "standard" conversion sequence, so that it
      // gets ranked with standard conversion sequences.
      DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
      ICS.setStandard();
      ICS.Standard.setAsIdentityConversion();
      ICS.Standard.setFromType(From->getType());
      ICS.Standard.setAllToTypes(ToType);
      ICS.Standard.CopyConstructor = Constructor;
      ICS.Standard.FoundCopyConstructor = Found;
      if (ToCanon != FromCanon)
        ICS.Standard.Second = ICK_Derived_To_Base;
    }
  }
  break;

case OR_Ambiguous:
  ICS.setAmbiguous();
  ICS.Ambiguous.setFromType(From->getType());
  ICS.Ambiguous.setToType(ToType);
  for (OverloadCandidateSet::iterator Cand = Conversions.begin();
       Cand != Conversions.end(); ++Cand)
    if (Cand->Best)
      ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
  break;

  // Fall through.
case OR_No_Viable_Function:
  ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
  break;
}

return ICS;
1395}

1397/// TryImplicitConversion - Attempt to perform an implicit conversion
1398/// from the given expression (Expr) to the given type (ToType). This
1399/// function returns an implicit conversion sequence that can be used
1400/// to perform the initialization. Given
1401///
1402///   void f(float f);
1403///   void g(int i) { f(i); }
1404///
1405/// this routine would produce an implicit conversion sequence to
1406/// describe the initialization of f from i, which will be a standard
1407/// conversion sequence containing an lvalue-to-rvalue conversion (C++
1408/// 4.1) followed by a floating-integral conversion (C++ 4.9).
1409//
1410/// Note that this routine only determines how the conversion can be
1411/// performed; it does not actually perform the conversion. As such,
1412/// it will not produce any diagnostics if no conversion is available,
1413/// but will instead return an implicit conversion sequence of kind
1414/// "BadConversion".
1415///
1416/// If @p SuppressUserConversions, then user-defined conversions are
1417/// not permitted.
1418/// If @p AllowExplicit, then explicit user-defined conversions are
1419/// permitted.
1420///
1421/// \param AllowObjCWritebackConversion Whether we allow the Objective-C
1422/// writeback conversion, which allows __autoreleasing id* parameters to
1423/// be initialized with __strong id* or __weak id* arguments.
1424static ImplicitConversionSequence
1425TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
                    bool SuppressUserConversions,
                    AllowedExplicit AllowExplicit,
                    bool InOverloadResolution,
                    bool CStyle,
                    bool AllowObjCWritebackConversion,
                    bool AllowObjCConversionOnExplicit) {
ImplicitConversionSequence ICS;
if (IsStandardConversion(S, From, ToType, InOverloadResolution,
                         ICS.Standard, CStyle, AllowObjCWritebackConversion)){
  ICS.setStandard();
  return ICS;
}

if (!S.getLangOpts().CPlusPlus) {
  ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
  return ICS;
}

// C++ [over.ics.user]p4:
//   A conversion of an expression of class type to the same class
//   type is given Exact Match rank, and a conversion of an
//   expression of class type to a base class of that type is
//   given Conversion rank, in spite of the fact that a copy/move
//   constructor (i.e., a user-defined conversion function) is
//   called for those cases.
QualType FromType = From->getType();
if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
    (S.Context.hasSameUnqualifiedType(FromType, ToType) ||
     S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
  ICS.setStandard();
  ICS.Standard.setAsIdentityConversion();
  ICS.Standard.setFromType(FromType);
  ICS.Standard.setAllToTypes(ToType);

  // We don't actually check at this point whether there is a valid
  // copy/move constructor, since overloading just assumes that it
  // exists. When we actually perform initialization, we'll find the
  // appropriate constructor to copy the returned object, if needed.
  ICS.Standard.CopyConstructor = nullptr;

  // Determine whether this is considered a derived-to-base conversion.
  if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
    ICS.Standard.Second = ICK_Derived_To_Base;

  return ICS;
}

return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
                                AllowExplicit, InOverloadResolution, CStyle,
                                AllowObjCWritebackConversion,
                                AllowObjCConversionOnExplicit);
1477}

1479ImplicitConversionSequence
1480Sema::TryImplicitConversion(Expr *From, QualType ToType,
                          bool SuppressUserConversions,
                          AllowedExplicit AllowExplicit,
                          bool InOverloadResolution,
                          bool CStyle,
                          bool AllowObjCWritebackConversion) {
return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions,
                               AllowExplicit, InOverloadResolution, CStyle,
                               AllowObjCWritebackConversion,
                               /*AllowObjCConversionOnExplicit=*/false);
1490}

1492/// PerformImplicitConversion - Perform an implicit conversion of the
1493/// expression From to the type ToType. Returns the
1494/// converted expression. Flavor is the kind of conversion we're
1495/// performing, used in the error message. If @p AllowExplicit,
1496/// explicit user-defined conversions are permitted.
1497ExprResult Sema::PerformImplicitConversion(Expr *From, QualType ToType,
                                         AssignmentAction Action,
                                         bool AllowExplicit) {
if (checkPlaceholderForOverload(*this, From))
  return ExprError();

// Objective-C ARC: Determine whether we will allow the writeback conversion.
bool AllowObjCWritebackConversion
  = getLangOpts().ObjCAutoRefCount &&
    (Action == AA_Passing || Action == AA_Sending);
if (getLangOpts().ObjC)
  CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
                                    From->getType(), From);
ImplicitConversionSequence ICS = ::TryImplicitConversion(
    *this, From, ToType,
    /*SuppressUserConversions=*/false,
    AllowExplicit ? AllowedExplicit::All : AllowedExplicit::None,
    /*InOverloadResolution=*/false,
    /*CStyle=*/false, AllowObjCWritebackConversion,
    /*AllowObjCConversionOnExplicit=*/false);
return PerformImplicitConversion(From, ToType, ICS, Action);
1518}

1520/// Determine whether the conversion from FromType to ToType is a valid
1521/// conversion that strips "noexcept" or "noreturn" off the nested function
1522/// type.
1523bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
                              QualType &ResultTy) {
if (Context.hasSameUnqualifiedType(FromType, ToType))
  return false;

// Permit the conversion F(t __attribute__((noreturn))) -> F(t)
//                    or F(t noexcept) -> F(t)
// where F adds one of the following at most once:
//   - a pointer
//   - a member pointer
//   - a block pointer
// Changes here need matching changes in FindCompositePointerType.
CanQualType CanTo = Context.getCanonicalType(ToType);
CanQualType CanFrom = Context.getCanonicalType(FromType);
Type::TypeClass TyClass = CanTo->getTypeClass();
if (TyClass != CanFrom->getTypeClass()) return false;
if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
  if (TyClass == Type::Pointer) {
    CanTo = CanTo.castAs<PointerType>()->getPointeeType();
    CanFrom = CanFrom.castAs<PointerType>()->getPointeeType();
  } else if (TyClass == Type::BlockPointer) {
    CanTo = CanTo.castAs<BlockPointerType>()->getPointeeType();
    CanFrom = CanFrom.castAs<BlockPointerType>()->getPointeeType();
  } else if (TyClass == Type::MemberPointer) {
    auto ToMPT = CanTo.castAs<MemberPointerType>();
    auto FromMPT = CanFrom.castAs<MemberPointerType>();
    // A function pointer conversion cannot change the class of the function.
    if (ToMPT->getClass() != FromMPT->getClass())
      return false;
    CanTo = ToMPT->getPointeeType();
    CanFrom = FromMPT->getPointeeType();
  } else {
    return false;
  }

  TyClass = CanTo->getTypeClass();
  if (TyClass != CanFrom->getTypeClass()) return false;
  if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
    return false;
}

const auto *FromFn = cast<FunctionType>(CanFrom);
FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();

const auto *ToFn = cast<FunctionType>(CanTo);
FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();

bool Changed = false;

// Drop 'noreturn' if not present in target type.
if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
  FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
  Changed = true;
}

// Drop 'noexcept' if not present in target type.
if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
  const auto *ToFPT = cast<FunctionProtoType>(ToFn);
  if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
    FromFn = cast<FunctionType>(
        Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
                                                 EST_None)
               .getTypePtr());
    Changed = true;
  }

  // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
  // only if the ExtParameterInfo lists of the two function prototypes can be
  // merged and the merged list is identical to ToFPT's ExtParameterInfo list.
  SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
  bool CanUseToFPT, CanUseFromFPT;
  if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
                                    CanUseFromFPT, NewParamInfos) &&
      CanUseToFPT && !CanUseFromFPT) {
    FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
    ExtInfo.ExtParameterInfos =
        NewParamInfos.empty() ? nullptr : NewParamInfos.data();
    QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
                                          FromFPT->getParamTypes(), ExtInfo);
    FromFn = QT->getAs<FunctionType>();
    Changed = true;
  }
}

if (!Changed)
  return false;

assert(QualType(FromFn, 0).isCanonical())((void)0);
if (QualType(FromFn, 0) != CanTo) return false;

ResultTy = ToType;
return true;
1615}

1617/// Determine whether the conversion from FromType to ToType is a valid
1618/// vector conversion.
1619///
1620/// \param ICK Will be set to the vector conversion kind, if this is a vector
1621/// conversion.
1622static bool IsVectorConversion(Sema &S, QualType FromType,
                             QualType ToType, ImplicitConversionKind &ICK) {
// We need at least one of these types to be a vector type to have a vector
// conversion.
if (!ToType->isVectorType() && !FromType->isVectorType())
  return false;

// Identical types require no conversions.
if (S.Context.hasSameUnqualifiedType(FromType, ToType))
  return false;

// There are no conversions between extended vector types, only identity.
if (ToType->isExtVectorType()) {
  // There are no conversions between extended vector types other than the
  // identity conversion.
  if (FromType->isExtVectorType())
    return false;

  // Vector splat from any arithmetic type to a vector.
  if (FromType->isArithmeticType()) {
    ICK = ICK_Vector_Splat;
    return true;
  }
}

if (ToType->isSizelessBuiltinType() || FromType->isSizelessBuiltinType())
  if (S.Context.areCompatibleSveTypes(FromType, ToType) ||
      S.Context.areLaxCompatibleSveTypes(FromType, ToType)) {
    ICK = ICK_SVE_Vector_Conversion;
    return true;
  }

// We can perform the conversion between vector types in the following cases:
// 1)vector types are equivalent AltiVec and GCC vector types
// 2)lax vector conversions are permitted and the vector types are of the
//   same size
// 3)the destination type does not have the ARM MVE strict-polymorphism
//   attribute, which inhibits lax vector conversion for overload resolution
//   only
if (ToType->isVectorType() && FromType->isVectorType()) {
  if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
      (S.isLaxVectorConversion(FromType, ToType) &&
       !ToType->hasAttr(attr::ArmMveStrictPolymorphism))) {
    ICK = ICK_Vector_Conversion;
    return true;
  }
}

return false;
1671}

1673static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
                              bool InOverloadResolution,
                              StandardConversionSequence &SCS,
                              bool CStyle);

1678/// IsStandardConversion - Determines whether there is a standard
1679/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
1680/// expression From to the type ToType. Standard conversion sequences
1681/// only consider non-class types; for conversions that involve class
1682/// types, use TryImplicitConversion. If a conversion exists, SCS will
1683/// contain the standard conversion sequence required to perform this
1684/// conversion and this routine will return true. Otherwise, this
1685/// routine will return false and the value of SCS is unspecified.
1686static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
                               bool InOverloadResolution,
                               StandardConversionSequence &SCS,
                               bool CStyle,
                               bool AllowObjCWritebackConversion) {
QualType FromType = From->getType();

// Standard conversions (C++ [conv])
SCS.setAsIdentityConversion();
SCS.IncompatibleObjC = false;
SCS.setFromType(FromType);
SCS.CopyConstructor = nullptr;

// There are no standard conversions for class types in C++, so
// abort early. When overloading in C, however, we do permit them.
if (S.getLangOpts().CPlusPlus &&
    (FromType->isRecordType() || ToType->isRecordType()))
  return false;

// The first conversion can be an lvalue-to-rvalue conversion,
// array-to-pointer conversion, or function-to-pointer conversion
// (C++ 4p1).

if (FromType == S.Context.OverloadTy) {
  DeclAccessPair AccessPair;
  if (FunctionDecl *Fn
        = S.ResolveAddressOfOverloadedFunction(From, ToType, false,
                                               AccessPair)) {
    // We were able to resolve the address of the overloaded function,
    // so we can convert to the type of that function.
    FromType = Fn->getType();
    SCS.setFromType(FromType);

    // we can sometimes resolve &foo<int> regardless of ToType, so check
    // if the type matches (identity) or we are converting to bool
    if (!S.Context.hasSameUnqualifiedType(
                    S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
      QualType resultTy;
      // if the function type matches except for [[noreturn]], it's ok
      if (!S.IsFunctionConversion(FromType,
            S.ExtractUnqualifiedFunctionType(ToType), resultTy))
        // otherwise, only a boolean conversion is standard
        if (!ToType->isBooleanType())
          return false;
    }

    // Check if the "from" expression is taking the address of an overloaded
    // function and recompute the FromType accordingly. Take advantage of the
    // fact that non-static member functions *must* have such an address-of
    // expression.
    CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
    if (Method && !Method->isStatic()) {
      assert(isa<UnaryOperator>(From->IgnoreParens()) &&((void)0)
             "Non-unary operator on non-static member address")((void)0);
      assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()((void)0)
             == UO_AddrOf &&((void)0)
             "Non-address-of operator on non-static member address")((void)0);
      const Type *ClassType
        = S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
      FromType = S.Context.getMemberPointerType(FromType, ClassType);
    } else if (isa<UnaryOperator>(From->IgnoreParens())) {
      assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==((void)0)
             UO_AddrOf &&((void)0)
             "Non-address-of operator for overloaded function expression")((void)0);
      FromType = S.Context.getPointerType(FromType);
    }

    // Check that we've computed the proper type after overload resolution.
    // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
    // be calling it from within an NDEBUG block.
    assert(S.Context.hasSameType(((void)0)
      FromType,((void)0)
      S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()))((void)0);
  } else {
    return false;
  }
}
// Lvalue-to-rvalue conversion (C++11 4.1):
//   A glvalue (3.10) of a non-function, non-array type T can
//   be converted to a prvalue.
bool argIsLValue = From->isGLValue();
if (argIsLValue &&
    !FromType->isFunctionType() && !FromType->isArrayType() &&
    S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
  SCS.First = ICK_Lvalue_To_Rvalue;

  // C11 6.3.2.1p2:
  //   ... if the lvalue has atomic type, the value has the non-atomic version
  //   of the type of the lvalue ...
  if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
    FromType = Atomic->getValueType();

  // If T is a non-class type, the type of the rvalue is the
  // cv-unqualified version of T. Otherwise, the type of the rvalue
  // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
  // just strip the qualifiers because they don't matter.
  FromType = FromType.getUnqualifiedType();
} else if (FromType->isArrayType()) {
  // Array-to-pointer conversion (C++ 4.2)
  SCS.First = ICK_Array_To_Pointer;

  // An lvalue or rvalue of type "array of N T" or "array of unknown
  // bound of T" can be converted to an rvalue of type "pointer to
  // T" (C++ 4.2p1).
  FromType = S.Context.getArrayDecayedType(FromType);

  if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
    // This conversion is deprecated in C++03 (D.4)
    SCS.DeprecatedStringLiteralToCharPtr = true;

    // For the purpose of ranking in overload resolution
    // (13.3.3.1.1), this conversion is considered an
    // array-to-pointer conversion followed by a qualification
    // conversion (4.4). (C++ 4.2p2)
    SCS.Second = ICK_Identity;
    SCS.Third = ICK_Qualification;
    SCS.QualificationIncludesObjCLifetime = false;
    SCS.setAllToTypes(FromType);
    return true;
  }
} else if (FromType->isFunctionType() && argIsLValue) {
  // Function-to-pointer conversion (C++ 4.3).
  SCS.First = ICK_Function_To_Pointer;

  if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
    if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
      if (!S.checkAddressOfFunctionIsAvailable(FD))
        return false;

  // An lvalue of function type T can be converted to an rvalue of
  // type "pointer to T." The result is a pointer to the
  // function. (C++ 4.3p1).
  FromType = S.Context.getPointerType(FromType);
} else {
  // We don't require any conversions for the first step.
  SCS.First = ICK_Identity;
}
SCS.setToType(0, FromType);

// The second conversion can be an integral promotion, floating
// point promotion, integral conversion, floating point conversion,
// floating-integral conversion, pointer conversion,
// pointer-to-member conversion, or boolean conversion (C++ 4p1).
// For overloading in C, this can also be a "compatible-type"
// conversion.
bool IncompatibleObjC = false;
ImplicitConversionKind SecondICK = ICK_Identity;
if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
  // The unqualified versions of the types are the same: there's no
  // conversion to do.
  SCS.Second = ICK_Identity;
} else if (S.IsIntegralPromotion(From, FromType, ToType)) {
  // Integral promotion (C++ 4.5).
  SCS.Second = ICK_Integral_Promotion;
  FromType = ToType.getUnqualifiedType();
} else if (S.IsFloatingPointPromotion(FromType, ToType)) {
  // Floating point promotion (C++ 4.6).
  SCS.Second = ICK_Floating_Promotion;
  FromType = ToType.getUnqualifiedType();
} else if (S.IsComplexPromotion(FromType, ToType)) {
  // Complex promotion (Clang extension)
  SCS.Second = ICK_Complex_Promotion;
  FromType = ToType.getUnqualifiedType();
} else if (ToType->isBooleanType() &&
           (FromType->isArithmeticType() ||
            FromType->isAnyPointerType() ||
            FromType->isBlockPointerType() ||
            FromType->isMemberPointerType())) {
  // Boolean conversions (C++ 4.12).
  SCS.Second = ICK_Boolean_Conversion;
  FromType = S.Context.BoolTy;
} else if (FromType->isIntegralOrUnscopedEnumerationType() &&
           ToType->isIntegralType(S.Context)) {
  // Integral conversions (C++ 4.7).
  SCS.Second = ICK_Integral_Conversion;
  FromType = ToType.getUnqualifiedType();
} else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
  // Complex conversions (C99 6.3.1.6)
  SCS.Second = ICK_Complex_Conversion;
  FromType = ToType.getUnqualifiedType();
} else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
           (ToType->isAnyComplexType() && FromType->isArithmeticType())) {
  // Complex-real conversions (C99 6.3.1.7)
  SCS.Second = ICK_Complex_Real;
  FromType = ToType.getUnqualifiedType();
} else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
  // FIXME: disable conversions between long double and __float128 if
  // their representation is different until there is back end support
  // We of course allow this conversion if long double is really double.

  // Conversions between bfloat and other floats are not permitted.
  if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty)
    return false;
  if (&S.Context.getFloatTypeSemantics(FromType) !=
      &S.Context.getFloatTypeSemantics(ToType)) {
    bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty &&
                                  ToType == S.Context.LongDoubleTy) ||
                                 (FromType == S.Context.LongDoubleTy &&
                                  ToType == S.Context.Float128Ty));
    if (Float128AndLongDouble &&
        (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) ==
         &llvm::APFloat::PPCDoubleDouble()))
      return false;
  }
  // Floating point conversions (C++ 4.8).
  SCS.Second = ICK_Floating_Conversion;
  FromType = ToType.getUnqualifiedType();
} else if ((FromType->isRealFloatingType() &&
            ToType->isIntegralType(S.Context)) ||
           (FromType->isIntegralOrUnscopedEnumerationType() &&
            ToType->isRealFloatingType())) {
  // Conversions between bfloat and int are not permitted.
  if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
    return false;

  // Floating-integral conversions (C++ 4.9).
  SCS.Second = ICK_Floating_Integral;
  FromType = ToType.getUnqualifiedType();
} else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
  SCS.Second = ICK_Block_Pointer_Conversion;
} else if (AllowObjCWritebackConversion &&
           S.isObjCWritebackConversion(FromType, ToType, FromType)) {
  SCS.Second = ICK_Writeback_Conversion;
} else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
                                 FromType, IncompatibleObjC)) {
  // Pointer conversions (C++ 4.10).
  SCS.Second = ICK_Pointer_Conversion;
  SCS.IncompatibleObjC = IncompatibleObjC;
  FromType = FromType.getUnqualifiedType();
} else if (S.IsMemberPointerConversion(From, FromType, ToType,
                                       InOverloadResolution, FromType)) {
  // Pointer to member conversions (4.11).
  SCS.Second = ICK_Pointer_Member;
} else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
  SCS.Second = SecondICK;
  FromType = ToType.getUnqualifiedType();
} else if (!S.getLangOpts().CPlusPlus &&
           S.Context.typesAreCompatible(ToType, FromType)) {
  // Compatible conversions (Clang extension for C function overloading)
  SCS.Second = ICK_Compatible_Conversion;
  FromType = ToType.getUnqualifiedType();
} else if (IsTransparentUnionStandardConversion(S, From, ToType,
                                           InOverloadResolution,
                                           SCS, CStyle)) {
  SCS.Second = ICK_TransparentUnionConversion;
  FromType = ToType;
} else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
                               CStyle)) {
  // tryAtomicConversion has updated the standard conversion sequence
  // appropriately.
  return true;
} else if (ToType->isEventT() &&
           From->isIntegerConstantExpr(S.getASTContext()) &&
           From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
  SCS.Second = ICK_Zero_Event_Conversion;
  FromType = ToType;
} else if (ToType->isQueueT() &&
           From->isIntegerConstantExpr(S.getASTContext()) &&
           (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
  SCS.Second = ICK_Zero_Queue_Conversion;
  FromType = ToType;
} else if (ToType->isSamplerT() &&
           From->isIntegerConstantExpr(S.getASTContext())) {
  SCS.Second = ICK_Compatible_Conversion;
  FromType = ToType;
} else {
  // No second conversion required.
  SCS.Second = ICK_Identity;
}
SCS.setToType(1, FromType);

// The third conversion can be a function pointer conversion or a
// qualification conversion (C++ [conv.fctptr], [conv.qual]).
bool ObjCLifetimeConversion;
if (S.IsFunctionConversion(FromType, ToType, FromType)) {
  // Function pointer conversions (removing 'noexcept') including removal of
  // 'noreturn' (Clang extension).
  SCS.Third = ICK_Function_Conversion;
} else if (S.IsQualificationConversion(FromType, ToType, CStyle,
                                       ObjCLifetimeConversion)) {
  SCS.Third = ICK_Qualification;
  SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
  FromType = ToType;
} else {
  // No conversion required
  SCS.Third = ICK_Identity;
}

// C++ [over.best.ics]p6:
//   [...] Any difference in top-level cv-qualification is
//   subsumed by the initialization itself and does not constitute
//   a conversion. [...]
QualType CanonFrom = S.Context.getCanonicalType(FromType);
QualType CanonTo = S.Context.getCanonicalType(ToType);
if (CanonFrom.getLocalUnqualifiedType()
                                   == CanonTo.getLocalUnqualifiedType() &&
    CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
  FromType = ToType;
  CanonFrom = CanonTo;
}

SCS.setToType(2, FromType);

if (CanonFrom == CanonTo)
  return true;

// If we have not converted the argument type to the parameter type,
// this is a bad conversion sequence, unless we're resolving an overload in C.
if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
  return false;

ExprResult ER = ExprResult{From};
Sema::AssignConvertType Conv =
    S.CheckSingleAssignmentConstraints(ToType, ER,
                                       /*Diagnose=*/false,
                                       /*DiagnoseCFAudited=*/false,
                                       /*ConvertRHS=*/false);
ImplicitConversionKind SecondConv;
switch (Conv) {
case Sema::Compatible:
  SecondConv = ICK_C_Only_Conversion;
  break;
// For our purposes, discarding qualifiers is just as bad as using an
// incompatible pointer. Note that an IncompatiblePointer conversion can drop
// qualifiers, as well.
case Sema::CompatiblePointerDiscardsQualifiers:
case Sema::IncompatiblePointer:
case Sema::IncompatiblePointerSign:
  SecondConv = ICK_Incompatible_Pointer_Conversion;
  break;
default:
  return false;
}

// First can only be an lvalue conversion, so we pretend that this was the
// second conversion. First should already be valid from earlier in the
// function.
SCS.Second = SecondConv;
SCS.setToType(1, ToType);

// Third is Identity, because Second should rank us worse than any other
// conversion. This could also be ICK_Qualification, but it's simpler to just
// lump everything in with the second conversion, and we don't gain anything
// from making this ICK_Qualification.
SCS.Third = ICK_Identity;
SCS.setToType(2, ToType);
return true;
2033}

2035static bool
2036IsTransparentUnionStandardConversion(Sema &S, Expr* From,
                                   QualType &ToType,
                                   bool InOverloadResolution,
                                   StandardConversionSequence &SCS,
                                   bool CStyle) {

const RecordType *UT = ToType->getAsUnionType();
if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
  return false;
// The field to initialize within the transparent union.
RecordDecl *UD = UT->getDecl();
// It's compatible if the expression matches any of the fields.
for (const auto *it : UD->fields()) {
  if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
                           CStyle, /*AllowObjCWritebackConversion=*/false)) {
    ToType = it->getType();
    return true;
  }
}
return false;
2056}

2058/// IsIntegralPromotion - Determines whether the conversion from the
2059/// expression From (whose potentially-adjusted type is FromType) to
2060/// ToType is an integral promotion (C++ 4.5). If so, returns true and
2061/// sets PromotedType to the promoted type.
2062bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
const BuiltinType *To = ToType->getAs<BuiltinType>();
// All integers are built-in.
if (!To) {
  return false;
}

// An rvalue of type char, signed char, unsigned char, short int, or
// unsigned short int can be converted to an rvalue of type int if
// int can represent all the values of the source type; otherwise,
// the source rvalue can be converted to an rvalue of type unsigned
// int (C++ 4.5p1).
if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
    !FromType->isEnumeralType()) {
  if (// We can promote any signed, promotable integer type to an int
      (FromType->isSignedIntegerType() ||
       // We can promote any unsigned integer type whose size is
       // less than int to an int.
       Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
    return To->getKind() == BuiltinType::Int;
  }

  return To->getKind() == BuiltinType::UInt;
}

// C++11 [conv.prom]p3:
//   A prvalue of an unscoped enumeration type whose underlying type is not
//   fixed (7.2) can be converted to an rvalue a prvalue of the first of the
//   following types that can represent all the values of the enumeration
//   (i.e., the values in the range bmin to bmax as described in 7.2): int,
//   unsigned int, long int, unsigned long int, long long int, or unsigned
//   long long int. If none of the types in that list can represent all the
//   values of the enumeration, an rvalue a prvalue of an unscoped enumeration
//   type can be converted to an rvalue a prvalue of the extended integer type
//   with lowest integer conversion rank (4.13) greater than the rank of long
//   long in which all the values of the enumeration can be represented. If
//   there are two such extended types, the signed one is chosen.
// C++11 [conv.prom]p4:
//   A prvalue of an unscoped enumeration type whose underlying type is fixed
//   can be converted to a prvalue of its underlying type. Moreover, if
//   integral promotion can be applied to its underlying type, a prvalue of an
//   unscoped enumeration type whose underlying type is fixed can also be
//   converted to a prvalue of the promoted underlying type.
if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
  // C++0x 7.2p9: Note that this implicit enum to int conversion is not
  // provided for a scoped enumeration.
  if (FromEnumType->getDecl()->isScoped())
    return false;

  // We can perform an integral promotion to the underlying type of the enum,
  // even if that's not the promoted type. Note that the check for promoting
  // the underlying type is based on the type alone, and does not consider
  // the bitfield-ness of the actual source expression.
  if (FromEnumType->getDecl()->isFixed()) {
    QualType Underlying = FromEnumType->getDecl()->getIntegerType();
    return Context.hasSameUnqualifiedType(Underlying, ToType) ||
           IsIntegralPromotion(nullptr, Underlying, ToType);
  }

  // We have already pre-calculated the promotion type, so this is trivial.
  if (ToType->isIntegerType() &&
      isCompleteType(From->getBeginLoc(), FromType))
    return Context.hasSameUnqualifiedType(
        ToType, FromEnumType->getDecl()->getPromotionType());

  // C++ [conv.prom]p5:
  //   If the bit-field has an enumerated type, it is treated as any other
  //   value of that type for promotion purposes.
  //
  // ... so do not fall through into the bit-field checks below in C++.
  if (getLangOpts().CPlusPlus)
    return false;
}

// C++0x [conv.prom]p2:
//   A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
//   to an rvalue a prvalue of the first of the following types that can
//   represent all the values of its underlying type: int, unsigned int,
//   long int, unsigned long int, long long int, or unsigned long long int.
//   If none of the types in that list can represent all the values of its
//   underlying type, an rvalue a prvalue of type char16_t, char32_t,
//   or wchar_t can be converted to an rvalue a prvalue of its underlying
//   type.
if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
    ToType->isIntegerType()) {
  // Determine whether the type we're converting from is signed or
  // unsigned.
  bool FromIsSigned = FromType->isSignedIntegerType();
  uint64_t FromSize = Context.getTypeSize(FromType);

  // The types we'll try to promote to, in the appropriate
  // order. Try each of these types.
  QualType PromoteTypes[6] = {
    Context.IntTy, Context.UnsignedIntTy,
    Context.LongTy, Context.UnsignedLongTy ,
    Context.LongLongTy, Context.UnsignedLongLongTy
  };
  for (int Idx = 0; Idx < 6; ++Idx) {
    uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
    if (FromSize < ToSize ||
        (FromSize == ToSize &&
         FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
      // We found the type that we can promote to. If this is the
      // type we wanted, we have a promotion. Otherwise, no
      // promotion.
      return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
    }
  }
}

// An rvalue for an integral bit-field (9.6) can be converted to an
// rvalue of type int if int can represent all the values of the
// bit-field; otherwise, it can be converted to unsigned int if
// unsigned int can represent all the values of the bit-field. If
// the bit-field is larger yet, no integral promotion applies to
// it. If the bit-field has an enumerated type, it is treated as any
// other value of that type for promotion purposes (C++ 4.5p3).
// FIXME: We should delay checking of bit-fields until we actually perform the
// conversion.
//
// FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
// promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
// bit-fields and those whose underlying type is larger than int) for GCC
// compatibility.
if (From) {
  if (FieldDecl *MemberDecl = From->getSourceBitField()) {
    Optional<llvm::APSInt> BitWidth;
    if (FromType->isIntegralType(Context) &&
        (BitWidth =
             MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) {
      llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned());
      ToSize = Context.getTypeSize(ToType);

      // Are we promoting to an int from a bitfield that fits in an int?
      if (*BitWidth < ToSize ||
          (FromType->isSignedIntegerType() && *BitWidth <= ToSize)) {
        return To->getKind() == BuiltinType::Int;
      }

      // Are we promoting to an unsigned int from an unsigned bitfield
      // that fits into an unsigned int?
      if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) {
        return To->getKind() == BuiltinType::UInt;
      }

      return false;
    }
  }
}

// An rvalue of type bool can be converted to an rvalue of type int,
// with false becoming zero and true becoming one (C++ 4.5p4).
if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
  return true;
}

return false;
2219}

2221/// IsFloatingPointPromotion - Determines whether the conversion from
2222/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
2223/// returns true and sets PromotedType to the promoted type.
2224bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
  if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
    /// An rvalue of type float can be converted to an rvalue of type
    /// double. (C++ 4.6p1).
    if (FromBuiltin->getKind() == BuiltinType::Float &&
        ToBuiltin->getKind() == BuiltinType::Double)
      return true;

    // C99 6.3.1.5p1:
    //   When a float is promoted to double or long double, or a
    //   double is promoted to long double [...].
    if (!getLangOpts().CPlusPlus &&
        (FromBuiltin->getKind() == BuiltinType::Float ||
         FromBuiltin->getKind() == BuiltinType::Double) &&
        (ToBuiltin->getKind() == BuiltinType::LongDouble ||
         ToBuiltin->getKind() == BuiltinType::Float128))
      return true;

    // Half can be promoted to float.
    if (!getLangOpts().NativeHalfType &&
         FromBuiltin->getKind() == BuiltinType::Half &&
        ToBuiltin->getKind() == BuiltinType::Float)
      return true;
  }

return false;
2251}

2253/// Determine if a conversion is a complex promotion.
2254///
2255/// A complex promotion is defined as a complex -> complex conversion
2256/// where the conversion between the underlying real types is a
2257/// floating-point or integral promotion.
2258bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
const ComplexType *FromComplex = FromType->getAs<ComplexType>();
if (!FromComplex)
  return false;

const ComplexType *ToComplex = ToType->getAs<ComplexType>();
if (!ToComplex)
  return false;

return IsFloatingPointPromotion(FromComplex->getElementType(),
                                ToComplex->getElementType()) ||
  IsIntegralPromotion(nullptr, FromComplex->getElementType(),
                      ToComplex->getElementType());
2271}

2273/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
2274/// the pointer type FromPtr to a pointer to type ToPointee, with the
2275/// same type qualifiers as FromPtr has on its pointee type. ToType,
2276/// if non-empty, will be a pointer to ToType that may or may not have
2277/// the right set of qualifiers on its pointee.
2278///
2279static QualType
2280BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
                                 QualType ToPointee, QualType ToType,
                                 ASTContext &Context,
                                 bool StripObjCLifetime = false) {
assert((FromPtr->getTypeClass() == Type::Pointer ||((void)0)
        FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&((void)0)
       "Invalid similarly-qualified pointer type")((void)0);

/// Conversions to 'id' subsume cv-qualifier conversions.
if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
  return ToType.getUnqualifiedType();

QualType CanonFromPointee
  = Context.getCanonicalType(FromPtr->getPointeeType());
QualType CanonToPointee = Context.getCanonicalType(ToPointee);
Qualifiers Quals = CanonFromPointee.getQualifiers();

if (StripObjCLifetime)
  Quals.removeObjCLifetime();

// Exact qualifier match -> return the pointer type we're converting to.
if (CanonToPointee.getLocalQualifiers() == Quals) {
  // ToType is exactly what we need. Return it.
  if (!ToType.isNull())
    return ToType.getUnqualifiedType();

  // Build a pointer to ToPointee. It has the right qualifiers
  // already.
  if (isa<ObjCObjectPointerType>(ToType))
    return Context.getObjCObjectPointerType(ToPointee);
  return Context.getPointerType(ToPointee);
}

// Just build a canonical type that has the right qualifiers.
QualType QualifiedCanonToPointee
  = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);

if (isa<ObjCObjectPointerType>(ToType))
  return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
return Context.getPointerType(QualifiedCanonToPointee);
2320}

2322static bool isNullPointerConstantForConversion(Expr *Expr,
                                             bool InOverloadResolution,
                                             ASTContext &Context) {
// Handle value-dependent integral null pointer constants correctly.
// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
    Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
  return !InOverloadResolution;

return Expr->isNullPointerConstant(Context,
                  InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
                                      : Expr::NPC_ValueDependentIsNull);
2334}

2336/// IsPointerConversion - Determines whether the conversion of the
2337/// expression From, which has the (possibly adjusted) type FromType,
2338/// can be converted to the type ToType via a pointer conversion (C++
2339/// 4.10). If so, returns true and places the converted type (that
2340/// might differ from ToType in its cv-qualifiers at some level) into
2341/// ConvertedType.
2342///
2343/// This routine also supports conversions to and from block pointers
2344/// and conversions with Objective-C's 'id', 'id<protocols...>', and
2345/// pointers to interfaces. FIXME: Once we've determined the
2346/// appropriate overloading rules for Objective-C, we may want to
2347/// split the Objective-C checks into a different routine; however,
2348/// GCC seems to consider all of these conversions to be pointer
2349/// conversions, so for now they live here. IncompatibleObjC will be
2350/// set if the conversion is an allowed Objective-C conversion that
2351/// should result in a warning.
2352bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                             bool InOverloadResolution,
                             QualType& ConvertedType,
                             bool &IncompatibleObjC) {
IncompatibleObjC = false;
if (isObjCPointerConversion(FromType, ToType, ConvertedType,
                            IncompatibleObjC))
  return true;

// Conversion from a null pointer constant to any Objective-C pointer type.
if (ToType->isObjCObjectPointerType() &&
    isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
  ConvertedType = ToType;
  return true;
}

// Blocks: Block pointers can be converted to void*.
if (FromType->isBlockPointerType() && ToType->isPointerType() &&
    ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
  ConvertedType = ToType;
  return true;
}
// Blocks: A null pointer constant can be converted to a block
// pointer type.
if (ToType->isBlockPointerType() &&
    isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
  ConvertedType = ToType;
  return true;
}

// If the left-hand-side is nullptr_t, the right side can be a null
// pointer constant.
if (ToType->isNullPtrType() &&
    isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
  ConvertedType = ToType;
  return true;
}

const PointerType* ToTypePtr = ToType->getAs<PointerType>();
if (!ToTypePtr)
  return false;

// A null pointer constant can be converted to a pointer type (C++ 4.10p1).
if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
  ConvertedType = ToType;
  return true;
}

// Beyond this point, both types need to be pointers
// , including objective-c pointers.
QualType ToPointeeType = ToTypePtr->getPointeeType();
if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
    !getLangOpts().ObjCAutoRefCount) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(
                                    FromType->getAs<ObjCObjectPointerType>(),
                                                     ToPointeeType,
                                                     ToType, Context);
  return true;
}
const PointerType *FromTypePtr = FromType->getAs<PointerType>();
if (!FromTypePtr)
  return false;

QualType FromPointeeType = FromTypePtr->getPointeeType();

// If the unqualified pointee types are the same, this can't be a
// pointer conversion, so don't do all of the work below.
if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
  return false;

// An rvalue of type "pointer to cv T," where T is an object type,
// can be converted to an rvalue of type "pointer to cv void" (C++
// 4.10p2).
if (FromPointeeType->isIncompleteOrObjectType() &&
    ToPointeeType->isVoidType()) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
                                                     ToPointeeType,
                                                     ToType, Context,
                                                 /*StripObjCLifetime=*/true);
  return true;
}

// MSVC allows implicit function to void* type conversion.
if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
    ToPointeeType->isVoidType()) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
                                                     ToPointeeType,
                                                     ToType, Context);
  return true;
}

// When we're overloading in C, we allow a special kind of pointer
// conversion for compatible-but-not-identical pointee types.
if (!getLangOpts().CPlusPlus &&
    Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
                                                     ToPointeeType,
                                                     ToType, Context);
  return true;
}

// C++ [conv.ptr]p3:
//
//   An rvalue of type "pointer to cv D," where D is a class type,
//   can be converted to an rvalue of type "pointer to cv B," where
//   B is a base class (clause 10) of D. If B is an inaccessible
//   (clause 11) or ambiguous (10.2) base class of D, a program that
//   necessitates this conversion is ill-formed. The result of the
//   conversion is a pointer to the base class sub-object of the
//   derived class object. The null pointer value is converted to
//   the null pointer value of the destination type.
//
// Note that we do not check for ambiguity or inaccessibility
// here. That is handled by CheckPointerConversion.
if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
    ToPointeeType->isRecordType() &&
    !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
    IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
                                                     ToPointeeType,
                                                     ToType, Context);
  return true;
}

if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
    Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
  ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
                                                     ToPointeeType,
                                                     ToType, Context);
  return true;
}

return false;
2485}

2487/// Adopt the given qualifiers for the given type.
2488static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
Qualifiers TQs = T.getQualifiers();

// Check whether qualifiers already match.
if (TQs == Qs)
  return T;

if (Qs.compatiblyIncludes(TQs))
  return Context.getQualifiedType(T, Qs);

return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
2499}

2501/// isObjCPointerConversion - Determines whether this is an
2502/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
2503/// with the same arguments and return values.
2504bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
                                 QualType& ConvertedType,
                                 bool &IncompatibleObjC) {
if (!getLangOpts().ObjC)
  return false;

// The set of qualifiers on the type we're converting from.
Qualifiers FromQualifiers = FromType.getQualifiers();

// First, we handle all conversions on ObjC object pointer types.
const ObjCObjectPointerType* ToObjCPtr =
  ToType->getAs<ObjCObjectPointerType>();
const ObjCObjectPointerType *FromObjCPtr =
  FromType->getAs<ObjCObjectPointerType>();

if (ToObjCPtr && FromObjCPtr) {
  // If the pointee types are the same (ignoring qualifications),
  // then this is not a pointer conversion.
  if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
                                     FromObjCPtr->getPointeeType()))
    return false;

  // Conversion between Objective-C pointers.
  if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
    const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
    const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
    if (getLangOpts().CPlusPlus && LHS && RHS &&
        !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
                                              FromObjCPtr->getPointeeType()))
      return false;
    ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
                                                 ToObjCPtr->getPointeeType(),
                                                       ToType, Context);
    ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
    return true;
  }

  if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
    // Okay: this is some kind of implicit downcast of Objective-C
    // interfaces, which is permitted. However, we're going to
    // complain about it.
    IncompatibleObjC = true;
    ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
                                                 ToObjCPtr->getPointeeType(),
                                                       ToType, Context);
    ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
    return true;
  }
}
// Beyond this point, both types need to be C pointers or block pointers.
QualType ToPointeeType;
if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
  ToPointeeType = ToCPtr->getPointeeType();
else if (const BlockPointerType *ToBlockPtr =
          ToType->getAs<BlockPointerType>()) {
  // Objective C++: We're able to convert from a pointer to any object
  // to a block pointer type.
  if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
    ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
    return true;
  }
  ToPointeeType = ToBlockPtr->getPointeeType();
}
else if (FromType->getAs<BlockPointerType>() &&
         ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
  // Objective C++: We're able to convert from a block pointer type to a
  // pointer to any object.
  ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
  return true;
}
else
  return false;

QualType FromPointeeType;
if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
  FromPointeeType = FromCPtr->getPointeeType();
else if (const BlockPointerType *FromBlockPtr =
         FromType->getAs<BlockPointerType>())
  FromPointeeType = FromBlockPtr->getPointeeType();
else
  return false;

// If we have pointers to pointers, recursively check whether this
// is an Objective-C conversion.
if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
    isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
                            IncompatibleObjC)) {
  // We always complain about this conversion.
  IncompatibleObjC = true;
  ConvertedType = Context.getPointerType(ConvertedType);
  ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
  return true;
}
// Allow conversion of pointee being objective-c pointer to another one;
// as in I* to id.
if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
    ToPointeeType->getAs<ObjCObjectPointerType>() &&
    isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
                            IncompatibleObjC)) {

  ConvertedType = Context.getPointerType(ConvertedType);
  ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
  return true;
}

// If we have pointers to functions or blocks, check whether the only
// differences in the argument and result types are in Objective-C
// pointer conversions. If so, we permit the conversion (but
// complain about it).
const FunctionProtoType *FromFunctionType
  = FromPointeeType->getAs<FunctionProtoType>();
const FunctionProtoType *ToFunctionType
  = ToPointeeType->getAs<FunctionProtoType>();
if (FromFunctionType && ToFunctionType) {
  // If the function types are exactly the same, this isn't an
  // Objective-C pointer conversion.
  if (Context.getCanonicalType(FromPointeeType)
        == Context.getCanonicalType(ToPointeeType))
    return false;

  // Perform the quick checks that will tell us whether these
  // function types are obviously different.
  if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
      FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
      FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
    return false;

  bool HasObjCConversion = false;
  if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
      Context.getCanonicalType(ToFunctionType->getReturnType())) {
    // Okay, the types match exactly. Nothing to do.
  } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
                                     ToFunctionType->getReturnType(),
                                     ConvertedType, IncompatibleObjC)) {
    // Okay, we have an Objective-C pointer conversion.
    HasObjCConversion = true;
  } else {
    // Function types are too different. Abort.
    return false;
  }

  // Check argument types.
  for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
       ArgIdx != NumArgs; ++ArgIdx) {
    QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
    QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
    if (Context.getCanonicalType(FromArgType)
          == Context.getCanonicalType(ToArgType)) {
      // Okay, the types match exactly. Nothing to do.
    } else if (isObjCPointerConversion(FromArgType, ToArgType,
                                       ConvertedType, IncompatibleObjC)) {
      // Okay, we have an Objective-C pointer conversion.
      HasObjCConversion = true;
    } else {
      // Argument types are too different. Abort.
      return false;
    }
  }

  if (HasObjCConversion) {
    // We had an Objective-C conversion. Allow this pointer
    // conversion, but complain about it.
    ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
    IncompatibleObjC = true;
    return true;
  }
}

return false;
2673}

2675/// Determine whether this is an Objective-C writeback conversion,
2676/// used for parameter passing when performing automatic reference counting.
2677///
2678/// \param FromType The type we're converting form.
2679///
2680/// \param ToType The type we're converting to.
2681///
2682/// \param ConvertedType The type that will be produced after applying
2683/// this conversion.
2684bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
                                   QualType &ConvertedType) {
if (!getLangOpts().ObjCAutoRefCount ||
    Context.hasSameUnqualifiedType(FromType, ToType))
  return false;

// Parameter must be a pointer to __autoreleasing (with no other qualifiers).
QualType ToPointee;
if (const PointerType *ToPointer = ToType->getAs<PointerType>())
  ToPointee = ToPointer->getPointeeType();
else
  return false;

Qualifiers ToQuals = ToPointee.getQualifiers();
if (!ToPointee->isObjCLifetimeType() ||
    ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
    !ToQuals.withoutObjCLifetime().empty())
  return false;

// Argument must be a pointer to __strong to __weak.
QualType FromPointee;
if (const PointerType *FromPointer = FromType->getAs<PointerType>())
  FromPointee = FromPointer->getPointeeType();
else
  return false;

Qualifiers FromQuals = FromPointee.getQualifiers();
if (!FromPointee->isObjCLifetimeType() ||
    (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
     FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
  return false;

// Make sure that we have compatible qualifiers.
FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
if (!ToQuals.compatiblyIncludes(FromQuals))
  return false;

// Remove qualifiers from the pointee type we're converting from; they
// aren't used in the compatibility check belong, and we'll be adding back
// qualifiers (with __autoreleasing) if the compatibility check succeeds.
FromPointee = FromPointee.getUnqualifiedType();

// The unqualified form of the pointee types must be compatible.
ToPointee = ToPointee.getUnqualifiedType();
bool IncompatibleObjC;
if (Context.typesAreCompatible(FromPointee, ToPointee))
  FromPointee = ToPointee;
else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
                                  IncompatibleObjC))
  return false;

/// Construct the type we're converting to, which is a pointer to
/// __autoreleasing pointee.
FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
ConvertedType = Context.getPointerType(FromPointee);
return true;
2740}

2742bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
                                  QualType& ConvertedType) {
QualType ToPointeeType;
if (const BlockPointerType *ToBlockPtr =
      ToType->getAs<BlockPointerType>())
  ToPointeeType = ToBlockPtr->getPointeeType();
else
  return false;

QualType FromPointeeType;
if (const BlockPointerType *FromBlockPtr =
    FromType->getAs<BlockPointerType>())
  FromPointeeType = FromBlockPtr->getPointeeType();
else
  return false;
// We have pointer to blocks, check whether the only
// differences in the argument and result types are in Objective-C
// pointer conversions. If so, we permit the conversion.

const FunctionProtoType *FromFunctionType
  = FromPointeeType->getAs<FunctionProtoType>();
const FunctionProtoType *ToFunctionType
  = ToPointeeType->getAs<FunctionProtoType>();

if (!FromFunctionType || !ToFunctionType)
  return false;

if (Context.hasSameType(FromPointeeType, ToPointeeType))
  return true;

// Perform the quick checks that will tell us whether these
// function types are obviously different.
if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
    FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
  return false;

FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
if (FromEInfo != ToEInfo)
  return false;

bool IncompatibleObjC = false;
if (Context.hasSameType(FromFunctionType->getReturnType(),
                        ToFunctionType->getReturnType())) {
  // Okay, the types match exactly. Nothing to do.
} else {
  QualType RHS = FromFunctionType->getReturnType();
  QualType LHS = ToFunctionType->getReturnType();
  if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
      !RHS.hasQualifiers() && LHS.hasQualifiers())
     LHS = LHS.getUnqualifiedType();

   if (Context.hasSameType(RHS,LHS)) {
     // OK exact match.
   } else if (isObjCPointerConversion(RHS, LHS,
                                      ConvertedType, IncompatibleObjC)) {
   if (IncompatibleObjC)
     return false;
   // Okay, we have an Objective-C pointer conversion.
   }
   else
     return false;
 }

 // Check argument types.
 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
      ArgIdx != NumArgs; ++ArgIdx) {
   IncompatibleObjC = false;
   QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
   QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
   if (Context.hasSameType(FromArgType, ToArgType)) {
     // Okay, the types match exactly. Nothing to do.
   } else if (isObjCPointerConversion(ToArgType, FromArgType,
                                      ConvertedType, IncompatibleObjC)) {
     if (IncompatibleObjC)
       return false;
     // Okay, we have an Objective-C pointer conversion.
   } else
     // Argument types are too different. Abort.
     return false;
 }

 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
 bool CanUseToFPT, CanUseFromFPT;
 if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
                                    CanUseToFPT, CanUseFromFPT,
                                    NewParamInfos))
   return false;

 ConvertedType = ToType;
 return true;
2833}

2835enum {
ft_default,
ft_different_class,
ft_parameter_arity,
ft_parameter_mismatch,
ft_return_type,
ft_qualifer_mismatch,
ft_noexcept
2843};

2845/// Attempts to get the FunctionProtoType from a Type. Handles
2846/// MemberFunctionPointers properly.
2847static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
if (auto *FPT = FromType->getAs<FunctionProtoType>())
  return FPT;

if (auto *MPT = FromType->getAs<MemberPointerType>())
  return MPT->getPointeeType()->getAs<FunctionProtoType>();

return nullptr;
2855}

2857/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
2858/// function types.  Catches different number of parameter, mismatch in
2859/// parameter types, and different return types.
2860void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                    QualType FromType, QualType ToType) {
// If either type is not valid, include no extra info.
if (FromType.isNull() || ToType.isNull()) {
  PDiag << ft_default;
  return;
}

// Get the function type from the pointers.
if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
  const auto *FromMember = FromType->castAs<MemberPointerType>(),
             *ToMember = ToType->castAs<MemberPointerType>();
  if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
    PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
          << QualType(FromMember->getClass(), 0);
    return;
  }
  FromType = FromMember->getPointeeType();
  ToType = ToMember->getPointeeType();
}

if (FromType->isPointerType())
  FromType = FromType->getPointeeType();
if (ToType->isPointerType())
  ToType = ToType->getPointeeType();

// Remove references.
FromType = FromType.getNonReferenceType();
ToType = ToType.getNonReferenceType();

// Don't print extra info for non-specialized template functions.
if (FromType->isInstantiationDependentType() &&
    !FromType->getAs<TemplateSpecializationType>()) {
  PDiag << ft_default;
  return;
}

// No extra info for same types.
if (Context.hasSameType(FromType, ToType)) {
  PDiag << ft_default;
  return;
}

const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
                        *ToFunction = tryGetFunctionProtoType(ToType);

// Both types need to be function types.
if (!FromFunction || !ToFunction) {
  PDiag << ft_default;
  return;
}

if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
  PDiag << ft_parameter_arity << ToFunction->getNumParams()
        << FromFunction->getNumParams();
  return;
}

// Handle different parameter types.
unsigned ArgPos;
if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
  PDiag << ft_parameter_mismatch << ArgPos + 1
        << ToFunction->getParamType(ArgPos)
        << FromFunction->getParamType(ArgPos);
  return;
}

// Handle different return type.
if (!Context.hasSameType(FromFunction->getReturnType(),
                         ToFunction->getReturnType())) {
  PDiag << ft_return_type << ToFunction->getReturnType()
        << FromFunction->getReturnType();
  return;
}

if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
  PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
        << FromFunction->getMethodQuals();
  return;
}

// Handle exception specification differences on canonical type (in C++17
// onwards).
if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
        ->isNothrow() !=
    cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
        ->isNothrow()) {
  PDiag << ft_noexcept;
  return;
}

// Unable to find a difference, so add no extra info.
PDiag << ft_default;
2953}

2955/// FunctionParamTypesAreEqual - This routine checks two function proto types
2956/// for equality of their argument types. Caller has already checked that
2957/// they have same number of arguments.  If the parameters are different,
2958/// ArgPos will have the parameter index of the first different parameter.
2959bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
                                    const FunctionProtoType *NewType,
                                    unsigned *ArgPos) {
for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
                                            N = NewType->param_type_begin(),
                                            E = OldType->param_type_end();
     O && (O != E); ++O, ++N) {
  // Ignore address spaces in pointee type. This is to disallow overloading
  // on __ptr32/__ptr64 address spaces.
  QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
  QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());

  if (!Context.hasSameType(Old, New)) {
    if (ArgPos)
      *ArgPos = O - OldType->param_type_begin();
    return false;
  }
}
return true;
2978}

2980/// CheckPointerConversion - Check the pointer conversion from the
2981/// expression From to the type ToType. This routine checks for
2982/// ambiguous or inaccessible derived-to-base pointer
2983/// conversions for which IsPointerConversion has already returned
2984/// true. It returns true and produces a diagnostic if there was an
2985/// error, or returns false otherwise.
2986bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
                                CastKind &Kind,
                                CXXCastPath& BasePath,
                                bool IgnoreBaseAccess,
                                bool Diagnose) {
QualType FromType = From->getType();
bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;

Kind = CK_BitCast;

if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
    From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
        Expr::NPCK_ZeroExpression) {
  if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
    DiagRuntimeBehavior(From->getExprLoc(), From,
                        PDiag(diag::warn_impcast_bool_to_null_pointer)
                          << ToType << From->getSourceRange());
  else if (!isUnevaluatedContext())
    Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
      << ToType << From->getSourceRange();
}
if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
  if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
    QualType FromPointeeType = FromPtrType->getPointeeType(),
             ToPointeeType   = ToPtrType->getPointeeType();

    if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
        !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
      // We must have a derived-to-base conversion. Check an
      // ambiguous or inaccessible conversion.
      unsigned InaccessibleID = 0;
      unsigned AmbiguousID = 0;
      if (Diagnose) {
        InaccessibleID = diag::err_upcast_to_inaccessible_base;
        AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
      }
      if (CheckDerivedToBaseConversion(
              FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
              From->getExprLoc(), From->getSourceRange(), DeclarationName(),
              &BasePath, IgnoreBaseAccess))
        return true;

      // The conversion was successful.
      Kind = CK_DerivedToBase;
    }

    if (Diagnose && !IsCStyleOrFunctionalCast &&
        FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
      assert(getLangOpts().MSVCCompat &&((void)0)
             "this should only be possible with MSVCCompat!")((void)0);
      Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
          << From->getSourceRange();
    }
  }
} else if (const ObjCObjectPointerType *ToPtrType =
             ToType->getAs<ObjCObjectPointerType>()) {
  if (const ObjCObjectPointerType *FromPtrType =
        FromType->getAs<ObjCObjectPointerType>()) {
    // Objective-C++ conversions are always okay.
    // FIXME: We should have a different class of conversions for the
    // Objective-C++ implicit conversions.
    if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
      return false;
  } else if (FromType->isBlockPointerType()) {
    Kind = CK_BlockPointerToObjCPointerCast;
  } else {
    Kind = CK_CPointerToObjCPointerCast;
  }
} else if (ToType->isBlockPointerType()) {
  if (!FromType->isBlockPointerType())
    Kind = CK_AnyPointerToBlockPointerCast;
}

// We shouldn't fall into this case unless it's valid for other
// reasons.
if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
  Kind = CK_NullToPointer;

return false;
3065}

3067/// IsMemberPointerConversion - Determines whether the conversion of the
3068/// expression From, which has the (possibly adjusted) type FromType, can be
3069/// converted to the type ToType via a member pointer conversion (C++ 4.11).
3070/// If so, returns true and places the converted type (that might differ from
3071/// ToType in its cv-qualifiers at some level) into ConvertedType.
3072bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
                                   QualType ToType,
                                   bool InOverloadResolution,
                                   QualType &ConvertedType) {
const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
if (!ToTypePtr)
  return false;

// A null pointer constant can be converted to a member pointer (C++ 4.11p1)
if (From->isNullPointerConstant(Context,
                  InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
                                      : Expr::NPC_ValueDependentIsNull)) {
  ConvertedType = ToType;
  return true;
}

// Otherwise, both types have to be member pointers.
const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
if (!FromTypePtr)
  return false;

// A pointer to member of B can be converted to a pointer to member of D,
// where D is derived from B (C++ 4.11p2).
QualType FromClass(FromTypePtr->getClass(), 0);
QualType ToClass(ToTypePtr->getClass(), 0);

if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
    IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
  ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
                                               ToClass.getTypePtr());
  return true;
}

return false;
3106}

3108/// CheckMemberPointerConversion - Check the member pointer conversion from the
3109/// expression From to the type ToType. This routine checks for ambiguous or
3110/// virtual or inaccessible base-to-derived member pointer conversions
3111/// for which IsMemberPointerConversion has already returned true. It returns
3112/// true and produces a diagnostic if there was an error, or returns false
3113/// otherwise.
3114bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
                                      CastKind &Kind,
                                      CXXCastPath &BasePath,
                                      bool IgnoreBaseAccess) {
QualType FromType = From->getType();
const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
if (!FromPtrType) {
  // This must be a null pointer to member pointer conversion
  assert(From->isNullPointerConstant(Context,((void)0)
                                     Expr::NPC_ValueDependentIsNull) &&((void)0)
         "Expr must be null pointer constant!")((void)0);
  Kind = CK_NullToMemberPointer;
  return false;
}

const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
assert(ToPtrType && "No member pointer cast has a target type "((void)0)
                    "that is not a member pointer.")((void)0);

QualType FromClass = QualType(FromPtrType->getClass(), 0);
QualType ToClass   = QualType(ToPtrType->getClass(), 0);

// FIXME: What about dependent types?
assert(FromClass->isRecordType() && "Pointer into non-class.")((void)0);
assert(ToClass->isRecordType() && "Pointer into non-class.")((void)0);

CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                   /*DetectVirtual=*/true);
bool DerivationOkay =
    IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
assert(DerivationOkay &&((void)0)
       "Should not have been called if derivation isn't OK.")((void)0);
(void)DerivationOkay;

if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
                                getUnqualifiedType())) {
  std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
  Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
    << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
  return true;
}

if (const RecordType *VBase = Paths.getDetectedVirtual()) {
  Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
    << FromClass << ToClass << QualType(VBase, 0)
    << From->getSourceRange();
  return true;
}

if (!IgnoreBaseAccess)
  CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
                       Paths.front(),
                       diag::err_downcast_from_inaccessible_base);

// Must be a base to derived member conversion.
BuildBasePathArray(Paths, BasePath);
Kind = CK_BaseToDerivedMemberPointer;
return false;
3172}

3174/// Determine whether the lifetime conversion between the two given
3175/// qualifiers sets is nontrivial.
3176static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
                                             Qualifiers ToQuals) {
// Converting anything to const __unsafe_unretained is trivial.
if (ToQuals.hasConst() &&
    ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
  return false;

return true;
3184}

3186/// Perform a single iteration of the loop for checking if a qualification
3187/// conversion is valid.
3188///
3189/// Specifically, check whether any change between the qualifiers of \p
3190/// FromType and \p ToType is permissible, given knowledge about whether every
3191/// outer layer is const-qualified.
3192static bool isQualificationConversionStep(QualType FromType, QualType ToType,
                                        bool CStyle, bool IsTopLevel,
                                        bool &PreviousToQualsIncludeConst,
                                        bool &ObjCLifetimeConversion) {
Qualifiers FromQuals = FromType.getQualifiers();
Qualifiers ToQuals = ToType.getQualifiers();

// Ignore __unaligned qualifier if this type is void.
if (ToType.getUnqualifiedType()->isVoidType())
  FromQuals.removeUnaligned();

// Objective-C ARC:
//   Check Objective-C lifetime conversions.
if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
  if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
    if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
      ObjCLifetimeConversion = true;
    FromQuals.removeObjCLifetime();
    ToQuals.removeObjCLifetime();
  } else {
    // Qualification conversions cannot cast between different
    // Objective-C lifetime qualifiers.
    return false;
  }
}

// Allow addition/removal of GC attributes but not changing GC attributes.
if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
    (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
  FromQuals.removeObjCGCAttr();
  ToQuals.removeObjCGCAttr();
}

//   -- for every j > 0, if const is in cv 1,j then const is in cv
//      2,j, and similarly for volatile.
if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
  return false;

// If address spaces mismatch:
//  - in top level it is only valid to convert to addr space that is a
//    superset in all cases apart from C-style casts where we allow
//    conversions between overlapping address spaces.
//  - in non-top levels it is not a valid conversion.
if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
    (!IsTopLevel ||
     !(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
       (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
  return false;

//   -- if the cv 1,j and cv 2,j are different, then const is in
//      every cv for 0 < k < j.
if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
    !PreviousToQualsIncludeConst)
  return false;

// Keep track of whether all prior cv-qualifiers in the "to" type
// include const.
PreviousToQualsIncludeConst =
    PreviousToQualsIncludeConst && ToQuals.hasConst();
return true;
3252}

3254/// IsQualificationConversion - Determines whether the conversion from
3255/// an rvalue of type FromType to ToType is a qualification conversion
3256/// (C++ 4.4).
3257///
3258/// \param ObjCLifetimeConversion Output parameter that will be set to indicate
3259/// when the qualification conversion involves a change in the Objective-C
3260/// object lifetime.
3261bool
3262Sema::IsQualificationConversion(QualType FromType, QualType ToType,
                              bool CStyle, bool &ObjCLifetimeConversion) {
FromType = Context.getCanonicalType(FromType);
ToType = Context.getCanonicalType(ToType);
ObjCLifetimeConversion = false;

// If FromType and ToType are the same type, this is not a
// qualification conversion.
if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
  return false;

// (C++ 4.4p4):
//   A conversion can add cv-qualifiers at levels other than the first
//   in multi-level pointers, subject to the following rules: [...]
bool PreviousToQualsIncludeConst = true;
bool UnwrappedAnyPointer = false;
while (Context.UnwrapSimilarTypes(FromType, ToType)) {
  if (!isQualificationConversionStep(
          FromType, ToType, CStyle, !UnwrappedAnyPointer,
          PreviousToQualsIncludeConst, ObjCLifetimeConversion))
    return false;
  UnwrappedAnyPointer = true;
}

// We are left with FromType and ToType being the pointee types
// after unwrapping the original FromType and ToType the same number
// of times. If we unwrapped any pointers, and if FromType and
// ToType have the same unqualified type (since we checked
// qualifiers above), then this is a qualification conversion.
return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
3292}

3294/// - Determine whether this is a conversion from a scalar type to an
3295/// atomic type.
3296///
3297/// If successful, updates \c SCS's second and third steps in the conversion
3298/// sequence to finish the conversion.
3299static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
                              bool InOverloadResolution,
                              StandardConversionSequence &SCS,
                              bool CStyle) {
const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
if (!ToAtomic)
  return false;

StandardConversionSequence InnerSCS;
if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
                          InOverloadResolution, InnerSCS,
                          CStyle, /*AllowObjCWritebackConversion=*/false))
  return false;

SCS.Second = InnerSCS.Second;
SCS.setToType(1, InnerSCS.getToType(1));
SCS.Third = InnerSCS.Third;
SCS.QualificationIncludesObjCLifetime
  = InnerSCS.QualificationIncludesObjCLifetime;
SCS.setToType(2, InnerSCS.getToType(2));
return true;
3320}

3322static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
                                            CXXConstructorDecl *Constructor,
                                            QualType Type) {
const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
if (CtorType->getNumParams() > 0) {
  QualType FirstArg = CtorType->getParamType(0);
  if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
    return true;
}
return false;
3332}

3334static OverloadingResult
3335IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
                                     CXXRecordDecl *To,
                                     UserDefinedConversionSequence &User,
                                     OverloadCandidateSet &CandidateSet,
                                     bool AllowExplicit) {
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
for (auto *D : S.LookupConstructors(To)) {
  auto Info = getConstructorInfo(D);
  if (!Info)
    continue;

  bool Usable = !Info.Constructor->isInvalidDecl() &&
                S.isInitListConstructor(Info.Constructor);
  if (Usable) {
    bool SuppressUserConversions = false;
    if (Info.ConstructorTmpl)
      S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
                                     /*ExplicitArgs*/ nullptr, From,
                                     CandidateSet, SuppressUserConversions,
                                     /*PartialOverloading*/ false,
                                     AllowExplicit);
    else
      S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
                             CandidateSet, SuppressUserConversions,
                             /*PartialOverloading*/ false, AllowExplicit);
  }
}

bool HadMultipleCandidates = (CandidateSet.size() > 1);

OverloadCandidateSet::iterator Best;
switch (auto Result =
            CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
case OR_Deleted:
case OR_Success: {
  // Record the standard conversion we used and the conversion function.
  CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
  QualType ThisType = Constructor->getThisType();
  // Initializer lists don't have conversions as such.
  User.Before.setAsIdentityConversion();
  User.HadMultipleCandidates = HadMultipleCandidates;
  User.ConversionFunction = Constructor;
  User.FoundConversionFunction = Best->FoundDecl;
  User.After.setAsIdentityConversion();
  User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
  User.After.setAllToTypes(ToType);
  return Result;
}

case OR_No_Viable_Function:
  return OR_No_Viable_Function;
case OR_Ambiguous:
  return OR_Ambiguous;
}

llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
3391}

3393/// Determines whether there is a user-defined conversion sequence
3394/// (C++ [over.ics.user]) that converts expression From to the type
3395/// ToType. If such a conversion exists, User will contain the
3396/// user-defined conversion sequence that performs such a conversion
3397/// and this routine will return true. Otherwise, this routine returns
3398/// false and User is unspecified.
3399///
3400/// \param AllowExplicit  true if the conversion should consider C++0x
3401/// "explicit" conversion functions as well as non-explicit conversion
3402/// functions (C++0x [class.conv.fct]p2).
3403///
3404/// \param AllowObjCConversionOnExplicit true if the conversion should
3405/// allow an extra Objective-C pointer conversion on uses of explicit
3406/// constructors. Requires \c AllowExplicit to also be set.
3407static OverloadingResult
3408IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
                      UserDefinedConversionSequence &User,
                      OverloadCandidateSet &CandidateSet,
                      AllowedExplicit AllowExplicit,
                      bool AllowObjCConversionOnExplicit) {
assert(AllowExplicit != AllowedExplicit::None ||((void)0)
       !AllowObjCConversionOnExplicit)((void)0);
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);

// Whether we will only visit constructors.
bool ConstructorsOnly = false;

// If the type we are conversion to is a class type, enumerate its
// constructors.
if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
  // C++ [over.match.ctor]p1:
  //   When objects of class type are direct-initialized (8.5), or
  //   copy-initialized from an expression of the same or a
  //   derived class type (8.5), overload resolution selects the
  //   constructor. [...] For copy-initialization, the candidate
  //   functions are all the converting constructors (12.3.1) of
  //   that class. The argument list is the expression-list within
  //   the parentheses of the initializer.
  if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
      (From->getType()->getAs<RecordType>() &&
       S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
    ConstructorsOnly = true;

  if (!S.isCompleteType(From->getExprLoc(), ToType)) {
    // We're not going to find any constructors.
  } else if (CXXRecordDecl *ToRecordDecl
               = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {

    Expr **Args = &From;
    unsigned NumArgs = 1;
    bool ListInitializing = false;
    if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
      // But first, see if there is an init-list-constructor that will work.
      OverloadingResult Result = IsInitializerListConstructorConversion(
          S, From, ToType, ToRecordDecl, User, CandidateSet,
          AllowExplicit == AllowedExplicit::All);
      if (Result != OR_No_Viable_Function)
        return Result;
      // Never mind.
      CandidateSet.clear(
          OverloadCandidateSet::CSK_InitByUserDefinedConversion);

      // If we're list-initializing, we pass the individual elements as
      // arguments, not the entire list.
      Args = InitList->getInits();
      NumArgs = InitList->getNumInits();
      ListInitializing = true;
    }

    for (auto *D : S.LookupConstructors(ToRecordDecl)) {
      auto Info = getConstructorInfo(D);
      if (!Info)
        continue;

      bool Usable = !Info.Constructor->isInvalidDecl();
      if (!ListInitializing)
        Usable = Usable && Info.Constructor->isConvertingConstructor(
                               /*AllowExplicit*/ true);
      if (Usable) {
        bool SuppressUserConversions = !ConstructorsOnly;
        // C++20 [over.best.ics.general]/4.5:
        //   if the target is the first parameter of a constructor [of class
        //   X] and the constructor [...] is a candidate by [...] the second
        //   phase of [over.match.list] when the initializer list has exactly
        //   one element that is itself an initializer list, [...] and the
        //   conversion is to X or reference to cv X, user-defined conversion
        //   sequences are not cnosidered.
        if (SuppressUserConversions && ListInitializing) {
          SuppressUserConversions =
              NumArgs == 1 && isa<InitListExpr>(Args[0]) &&
              isFirstArgumentCompatibleWithType(S.Context, Info.Constructor,
                                                ToType);
        }
        if (Info.ConstructorTmpl)
          S.AddTemplateOverloadCandidate(
              Info.ConstructorTmpl, Info.FoundDecl,
              /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
              CandidateSet, SuppressUserConversions,
              /*PartialOverloading*/ false,
              AllowExplicit == AllowedExplicit::All);
        else
          // Allow one user-defined conversion when user specifies a
          // From->ToType conversion via an static cast (c-style, etc).
          S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
                                 llvm::makeArrayRef(Args, NumArgs),
                                 CandidateSet, SuppressUserConversions,
                                 /*PartialOverloading*/ false,
                                 AllowExplicit == AllowedExplicit::All);
      }
    }
  }
}

// Enumerate conversion functions, if we're allowed to.
if (ConstructorsOnly || isa<InitListExpr>(From)) {
} else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
  // No conversion functions from incomplete types.
} else if (const RecordType *FromRecordType =
               From->getType()->getAs<RecordType>()) {
  if (CXXRecordDecl *FromRecordDecl
       = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
    // Add all of the conversion functions as candidates.
    const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
    for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
      DeclAccessPair FoundDecl = I.getPair();
      NamedDecl *D = FoundDecl.getDecl();
      CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
      if (isa<UsingShadowDecl>(D))
        D = cast<UsingShadowDecl>(D)->getTargetDecl();

      CXXConversionDecl *Conv;
      FunctionTemplateDecl *ConvTemplate;
      if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
        Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
      else
        Conv = cast<CXXConversionDecl>(D);

      if (ConvTemplate)
        S.AddTemplateConversionCandidate(
            ConvTemplate, FoundDecl, ActingContext, From, ToType,
            CandidateSet, AllowObjCConversionOnExplicit,
            AllowExplicit != AllowedExplicit::None);
      else
        S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
                                 CandidateSet, AllowObjCConversionOnExplicit,
                                 AllowExplicit != AllowedExplicit::None);
    }
  }
}

bool HadMultipleCandidates = (CandidateSet.size() > 1);

OverloadCandidateSet::iterator Best;
switch (auto Result =
            CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
case OR_Success:
case OR_Deleted:
  // Record the standard conversion we used and the conversion function.
  if (CXXConstructorDecl *Constructor
        = dyn_cast<CXXConstructorDecl>(Best->Function)) {
    // C++ [over.ics.user]p1:
    //   If the user-defined conversion is specified by a
    //   constructor (12.3.1), the initial standard conversion
    //   sequence converts the source type to the type required by
    //   the argument of the constructor.
    //
    QualType ThisType = Constructor->getThisType();
    if (isa<InitListExpr>(From)) {
      // Initializer lists don't have conversions as such.
      User.Before.setAsIdentityConversion();
    } else {
      if (Best->Conversions[0].isEllipsis())
        User.EllipsisConversion = true;
      else {
        User.Before = Best->Conversions[0].Standard;
        User.EllipsisConversion = false;
      }
    }
    User.HadMultipleCandidates = HadMultipleCandidates;
    User.ConversionFunction = Constructor;
    User.FoundConversionFunction = Best->FoundDecl;
    User.After.setAsIdentityConversion();
    User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
    User.After.setAllToTypes(ToType);
    return Result;
  }
  if (CXXConversionDecl *Conversion
               = dyn_cast<CXXConversionDecl>(Best->Function)) {
    // C++ [over.ics.user]p1:
    //
    //   [...] If the user-defined conversion is specified by a
    //   conversion function (12.3.2), the initial standard
    //   conversion sequence converts the source type to the
    //   implicit object parameter of the conversion function.
    User.Before = Best->Conversions[0].Standard;
    User.HadMultipleCandidates = HadMultipleCandidates;
    User.ConversionFunction = Conversion;
    User.FoundConversionFunction = Best->FoundDecl;
    User.EllipsisConversion = false;

    // C++ [over.ics.user]p2:
    //   The second standard conversion sequence converts the
    //   result of the user-defined conversion to the target type
    //   for the sequence. Since an implicit conversion sequence
    //   is an initialization, the special rules for
    //   initialization by user-defined conversion apply when
    //   selecting the best user-defined conversion for a
    //   user-defined conversion sequence (see 13.3.3 and
    //   13.3.3.1).
    User.After = Best->FinalConversion;
    return Result;
  }
  llvm_unreachable("Not a constructor or conversion function?")__builtin_unreachable();

case OR_No_Viable_Function:
  return OR_No_Viable_Function;

case OR_Ambiguous:
  return OR_Ambiguous;
}

llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
3615}

3617bool
3618Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
ImplicitConversionSequence ICS;
OverloadCandidateSet CandidateSet(From->getExprLoc(),
                                  OverloadCandidateSet::CSK_Normal);
OverloadingResult OvResult =
  IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
                          CandidateSet, AllowedExplicit::None, false);

if (!(OvResult == OR_Ambiguous ||
      (OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
  return false;

auto Cands = CandidateSet.CompleteCandidates(
    *this,
    OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
    From);
if (OvResult == OR_Ambiguous)
  Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
      << From->getType() << ToType << From->getSourceRange();
else { // OR_No_Viable_Function && !CandidateSet.empty()
  if (!RequireCompleteType(From->getBeginLoc(), ToType,
                           diag::err_typecheck_nonviable_condition_incomplete,
                           From->getType(), From->getSourceRange()))
    Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
        << false << From->getType() << From->getSourceRange() << ToType;
}

CandidateSet.NoteCandidates(
                            *this, From, Cands);
return true;
3648}

3650// Helper for compareConversionFunctions that gets the FunctionType that the
3651// conversion-operator return  value 'points' to, or nullptr.
3652static const FunctionType *
3653getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) {
const FunctionType *ConvFuncTy = Conv->getType()->castAs<FunctionType>();
const PointerType *RetPtrTy =
    ConvFuncTy->getReturnType()->getAs<PointerType>();

if (!RetPtrTy)
  return nullptr;

return RetPtrTy->getPointeeType()->getAs<FunctionType>();
3662}

3664/// Compare the user-defined conversion functions or constructors
3665/// of two user-defined conversion sequences to determine whether any ordering
3666/// is possible.
3667static ImplicitConversionSequence::CompareKind
3668compareConversionFunctions(Sema &S, FunctionDecl *Function1,
                         FunctionDecl *Function2) {
CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
CXXConversionDecl *Conv2 = dyn_cast_or_null<CXXConversionDecl>(Function2);
if (!Conv1 || !Conv2)
  return ImplicitConversionSequence::Indistinguishable;

if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda())
  return ImplicitConversionSequence::Indistinguishable;

// Objective-C++:
//   If both conversion functions are implicitly-declared conversions from
//   a lambda closure type to a function pointer and a block pointer,
//   respectively, always prefer the conversion to a function pointer,
//   because the function pointer is more lightweight and is more likely
//   to keep code working.
if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) {
  bool Block1 = Conv1->getConversionType()->isBlockPointerType();
  bool Block2 = Conv2->getConversionType()->isBlockPointerType();
  if (Block1 != Block2)
    return Block1 ? ImplicitConversionSequence::Worse
                  : ImplicitConversionSequence::Better;
}

// In order to support multiple calling conventions for the lambda conversion
// operator (such as when the free and member function calling convention is
// different), prefer the 'free' mechanism, followed by the calling-convention
// of operator(). The latter is in place to support the MSVC-like solution of
// defining ALL of the possible conversions in regards to calling-convention.
const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1);
const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2);

if (Conv1FuncRet && Conv2FuncRet &&
    Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) {
  CallingConv Conv1CC = Conv1FuncRet->getCallConv();
  CallingConv Conv2CC = Conv2FuncRet->getCallConv();

  CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator();
  const FunctionProtoType *CallOpProto =
      CallOp->getType()->getAs<FunctionProtoType>();

  CallingConv CallOpCC =
      CallOp->getType()->castAs<FunctionType>()->getCallConv();
  CallingConv DefaultFree = S.Context.getDefaultCallingConvention(
      CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
  CallingConv DefaultMember = S.Context.getDefaultCallingConvention(
      CallOpProto->isVariadic(), /*IsCXXMethod=*/true);

  CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC};
  for (CallingConv CC : PrefOrder) {
    if (Conv1CC == CC)
      return ImplicitConversionSequence::Better;
    if (Conv2CC == CC)
      return ImplicitConversionSequence::Worse;
  }
}

return ImplicitConversionSequence::Indistinguishable;
3726}

3728static bool hasDeprecatedStringLiteralToCharPtrConversion(
  const ImplicitConversionSequence &ICS) {
return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
       (ICS.isUserDefined() &&
        ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
3733}

3735/// CompareImplicitConversionSequences - Compare two implicit
3736/// conversion sequences to determine whether one is better than the
3737/// other or if they are indistinguishable (C++ 13.3.3.2).
3738static ImplicitConversionSequence::CompareKind
3739CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
                                 const ImplicitConversionSequence& ICS1,
                                 const ImplicitConversionSequence& ICS2)
3742{
// (C++ 13.3.3.2p2): When comparing the basic forms of implicit
// conversion sequences (as defined in 13.3.3.1)
//   -- a standard conversion sequence (13.3.3.1.1) is a better
//      conversion sequence than a user-defined conversion sequence or
//      an ellipsis conversion sequence, and
//   -- a user-defined conversion sequence (13.3.3.1.2) is a better
//      conversion sequence than an ellipsis conversion sequence
//      (13.3.3.1.3).
//
// C++0x [over.best.ics]p10:
//   For the purpose of ranking implicit conversion sequences as
//   described in 13.3.3.2, the ambiguous conversion sequence is
//   treated as a user-defined sequence that is indistinguishable
//   from any other user-defined conversion sequence.

// String literal to 'char *' conversion has been deprecated in C++03. It has
// been removed from C++11. We still accept this conversion, if it happens at
// the best viable function. Otherwise, this conversion is considered worse
// than ellipsis conversion. Consider this as an extension; this is not in the
// standard. For example:
//
// int &f(...);    // #1
// void f(char*);  // #2
// void g() { int &r = f("foo"); }
//
// In C++03, we pick #2 as the best viable function.
// In C++11, we pick #1 as the best viable function, because ellipsis
// conversion is better than string-literal to char* conversion (since there
// is no such conversion in C++11). If there was no #1 at all or #1 couldn't
// convert arguments, #2 would be the best viable function in C++11.
// If the best viable function has this conversion, a warning will be issued
// in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.

if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
    hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
    hasDeprecatedStringLiteralToCharPtrConversion(ICS2))
  return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
             ? ImplicitConversionSequence::Worse
             : ImplicitConversionSequence::Better;

if (ICS1.getKindRank() < ICS2.getKindRank())
  return ImplicitConversionSequence::Better;
if (ICS2.getKindRank() < ICS1.getKindRank())
  return ImplicitConversionSequence::Worse;

// The following checks require both conversion sequences to be of
// the same kind.
if (ICS1.getKind() != ICS2.getKind())
  return ImplicitConversionSequence::Indistinguishable;

ImplicitConversionSequence::CompareKind Result =
    ImplicitConversionSequence::Indistinguishable;

// Two implicit conversion sequences of the same form are
// indistinguishable conversion sequences unless one of the
// following rules apply: (C++ 13.3.3.2p3):

// List-initialization sequence L1 is a better conversion sequence than
// list-initialization sequence L2 if:
// - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
//   if not that,
// - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T",
//   and N1 is smaller than N2.,
// even if one of the other rules in this paragraph would otherwise apply.
if (!ICS1.isBad()) {
  if (ICS1.isStdInitializerListElement() &&
      !ICS2.isStdInitializerListElement())
    return ImplicitConversionSequence::Better;
  if (!ICS1.isStdInitializerListElement() &&
      ICS2.isStdInitializerListElement())
    return ImplicitConversionSequence::Worse;
}

if (ICS1.isStandard())
  // Standard conversion sequence S1 is a better conversion sequence than
  // standard conversion sequence S2 if [...]
  Result = CompareStandardConversionSequences(S, Loc,
                                              ICS1.Standard, ICS2.Standard);
else if (ICS1.isUserDefined()) {
  // User-defined conversion sequence U1 is a better conversion
  // sequence than another user-defined conversion sequence U2 if
  // they contain the same user-defined conversion function or
  // constructor and if the second standard conversion sequence of
  // U1 is better than the second standard conversion sequence of
  // U2 (C++ 13.3.3.2p3).
  if (ICS1.UserDefined.ConversionFunction ==
        ICS2.UserDefined.ConversionFunction)
    Result = CompareStandardConversionSequences(S, Loc,
                                                ICS1.UserDefined.After,
                                                ICS2.UserDefined.After);
  else
    Result = compareConversionFunctions(S,
                                        ICS1.UserDefined.ConversionFunction,
                                        ICS2.UserDefined.ConversionFunction);
}

return Result;
3840}

3842// Per 13.3.3.2p3, compare the given standard conversion sequences to
3843// determine if one is a proper subset of the other.
3844static ImplicitConversionSequence::CompareKind
3845compareStandardConversionSubsets(ASTContext &Context,
                               const StandardConversionSequence& SCS1,
                               const StandardConversionSequence& SCS2) {
ImplicitConversionSequence::CompareKind Result
  = ImplicitConversionSequence::Indistinguishable;

// the identity conversion sequence is considered to be a subsequence of
// any non-identity conversion sequence
if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
  return ImplicitConversionSequence::Better;
else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
  return ImplicitConversionSequence::Worse;

if (SCS1.Second != SCS2.Second) {
  if (SCS1.Second == ICK_Identity)
    Result = ImplicitConversionSequence::Better;
  else if (SCS2.Second == ICK_Identity)
    Result = ImplicitConversionSequence::Worse;
  else
    return ImplicitConversionSequence::Indistinguishable;
} else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
  return ImplicitConversionSequence::Indistinguishable;

if (SCS1.Third == SCS2.Third) {
  return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
                           : ImplicitConversionSequence::Indistinguishable;
}

if (SCS1.Third == ICK_Identity)
  return Result == ImplicitConversionSequence::Worse
           ? ImplicitConversionSequence::Indistinguishable
           : ImplicitConversionSequence::Better;

if (SCS2.Third == ICK_Identity)
  return Result == ImplicitConversionSequence::Better
           ? ImplicitConversionSequence::Indistinguishable
           : ImplicitConversionSequence::Worse;

return ImplicitConversionSequence::Indistinguishable;
3884}

3886/// Determine whether one of the given reference bindings is better
3887/// than the other based on what kind of bindings they are.
3888static bool
3889isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
                           const StandardConversionSequence &SCS2) {
// C++0x [over.ics.rank]p3b4:
//   -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
//      implicit object parameter of a non-static member function declared
//      without a ref-qualifier, and *either* S1 binds an rvalue reference
//      to an rvalue and S2 binds an lvalue reference *or S1 binds an
//      lvalue reference to a function lvalue and S2 binds an rvalue
//      reference*.
//
// FIXME: Rvalue references. We're going rogue with the above edits,
// because the semantics in the current C++0x working paper (N3225 at the
// time of this writing) break the standard definition of std::forward
// and std::reference_wrapper when dealing with references to functions.
// Proposed wording changes submitted to CWG for consideration.
if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
    SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
  return false;

return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
        SCS2.IsLvalueReference) ||
       (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
        !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
3912}

3914enum class FixedEnumPromotion {
None,
ToUnderlyingType,
ToPromotedUnderlyingType
3918};

3920/// Returns kind of fixed enum promotion the \a SCS uses.
3921static FixedEnumPromotion
3922getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {

if (SCS.Second != ICK_Integral_Promotion)
  return FixedEnumPromotion::None;

QualType FromType = SCS.getFromType();
if (!FromType->isEnumeralType())
  return FixedEnumPromotion::None;

EnumDecl *Enum = FromType->castAs<EnumType>()->getDecl();
if (!Enum->isFixed())
  return FixedEnumPromotion::None;

QualType UnderlyingType = Enum->getIntegerType();
if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
  return FixedEnumPromotion::ToUnderlyingType;

return FixedEnumPromotion::ToPromotedUnderlyingType;
3940}

3942/// CompareStandardConversionSequences - Compare two standard
3943/// conversion sequences to determine whether one is better than the
3944/// other or if they are indistinguishable (C++ 13.3.3.2p3).
3945static ImplicitConversionSequence::CompareKind
3946CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
                                 const StandardConversionSequence& SCS1,
                                 const StandardConversionSequence& SCS2)
3949{
// Standard conversion sequence S1 is a better conversion sequence
// than standard conversion sequence S2 if (C++ 13.3.3.2p3):

//  -- S1 is a proper subsequence of S2 (comparing the conversion
//     sequences in the canonical form defined by 13.3.3.1.1,
//     excluding any Lvalue Transformation; the identity conversion
//     sequence is considered to be a subsequence of any
//     non-identity conversion sequence) or, if not that,
if (ImplicitConversionSequence::CompareKind CK
      = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
  return CK;

//  -- the rank of S1 is better than the rank of S2 (by the rules
//     defined below), or, if not that,
ImplicitConversionRank Rank1 = SCS1.getRank();
ImplicitConversionRank Rank2 = SCS2.getRank();
if (Rank1 < Rank2)
  return ImplicitConversionSequence::Better;
else if (Rank2 < Rank1)
  return ImplicitConversionSequence::Worse;

// (C++ 13.3.3.2p4): Two conversion sequences with the same rank
// are indistinguishable unless one of the following rules
// applies:

//   A conversion that is not a conversion of a pointer, or
//   pointer to member, to bool is better than another conversion
//   that is such a conversion.
if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
  return SCS2.isPointerConversionToBool()
           ? ImplicitConversionSequence::Better
           : ImplicitConversionSequence::Worse;

// C++14 [over.ics.rank]p4b2:
// This is retroactively applied to C++11 by CWG 1601.
//
//   A conversion that promotes an enumeration whose underlying type is fixed
//   to its underlying type is better than one that promotes to the promoted
//   underlying type, if the two are different.
FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
    FEP1 != FEP2)
  return FEP1 == FixedEnumPromotion::ToUnderlyingType
             ? ImplicitConversionSequence::Better
             : ImplicitConversionSequence::Worse;

// C++ [over.ics.rank]p4b2:
//
//   If class B is derived directly or indirectly from class A,
//   conversion of B* to A* is better than conversion of B* to
//   void*, and conversion of A* to void* is better than conversion
//   of B* to void*.
bool SCS1ConvertsToVoid
  = SCS1.isPointerConversionToVoidPointer(S.Context);
bool SCS2ConvertsToVoid
  = SCS2.isPointerConversionToVoidPointer(S.Context);
if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
  // Exactly one of the conversion sequences is a conversion to
  // a void pointer; it's the worse conversion.
  return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
                            : ImplicitConversionSequence::Worse;
} else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
  // Neither conversion sequence converts to a void pointer; compare
  // their derived-to-base conversions.
  if (ImplicitConversionSequence::CompareKind DerivedCK
        = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
    return DerivedCK;
} else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
           !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
  // Both conversion sequences are conversions to void
  // pointers. Compare the source types to determine if there's an
  // inheritance relationship in their sources.
  QualType FromType1 = SCS1.getFromType();
  QualType FromType2 = SCS2.getFromType();

  // Adjust the types we're converting from via the array-to-pointer
  // conversion, if we need to.
  if (SCS1.First == ICK_Array_To_Pointer)
    FromType1 = S.Context.getArrayDecayedType(FromType1);
  if (SCS2.First == ICK_Array_To_Pointer)
    FromType2 = S.Context.getArrayDecayedType(FromType2);

  QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
  QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();

  if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
    return ImplicitConversionSequence::Better;
  else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
    return ImplicitConversionSequence::Worse;

  // Objective-C++: If one interface is more specific than the
  // other, it is the better one.
  const ObjCObjectPointerType* FromObjCPtr1
    = FromType1->getAs<ObjCObjectPointerType>();
  const ObjCObjectPointerType* FromObjCPtr2
    = FromType2->getAs<ObjCObjectPointerType>();
  if (FromObjCPtr1 && FromObjCPtr2) {
    bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
                                                        FromObjCPtr2);
    bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
                                                         FromObjCPtr1);
    if (AssignLeft != AssignRight) {
      return AssignLeft? ImplicitConversionSequence::Better
                       : ImplicitConversionSequence::Worse;
    }
  }
}

if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
  // Check for a better reference binding based on the kind of bindings.
  if (isBetterReferenceBindingKind(SCS1, SCS2))
    return ImplicitConversionSequence::Better;
  else if (isBetterReferenceBindingKind(SCS2, SCS1))
    return ImplicitConversionSequence::Worse;
}

// Compare based on qualification conversions (C++ 13.3.3.2p3,
// bullet 3).
if (ImplicitConversionSequence::CompareKind QualCK
      = CompareQualificationConversions(S, SCS1, SCS2))
  return QualCK;

if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
  // C++ [over.ics.rank]p3b4:
  //   -- S1 and S2 are reference bindings (8.5.3), and the types to
  //      which the references refer are the same type except for
  //      top-level cv-qualifiers, and the type to which the reference
  //      initialized by S2 refers is more cv-qualified than the type
  //      to which the reference initialized by S1 refers.
  QualType T1 = SCS1.getToType(2);
  QualType T2 = SCS2.getToType(2);
  T1 = S.Context.getCanonicalType(T1);
  T2 = S.Context.getCanonicalType(T2);
  Qualifiers T1Quals, T2Quals;
  QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
  QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
  if (UnqualT1 == UnqualT2) {
    // Objective-C++ ARC: If the references refer to objects with different
    // lifetimes, prefer bindings that don't change lifetime.
    if (SCS1.ObjCLifetimeConversionBinding !=
                                        SCS2.ObjCLifetimeConversionBinding) {
      return SCS1.ObjCLifetimeConversionBinding
                                         ? ImplicitConversionSequence::Worse
                                         : ImplicitConversionSequence::Better;
    }

    // If the type is an array type, promote the element qualifiers to the
    // type for comparison.
    if (isa<ArrayType>(T1) && T1Quals)
      T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
    if (isa<ArrayType>(T2) && T2Quals)
      T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
    if (T2.isMoreQualifiedThan(T1))
      return ImplicitConversionSequence::Better;
    if (T1.isMoreQualifiedThan(T2))
      return ImplicitConversionSequence::Worse;
  }
}

// In Microsoft mode (below 19.28), prefer an integral conversion to a
// floating-to-integral conversion if the integral conversion
// is between types of the same size.
// For example:
// void f(float);
// void f(int);
// int main {
//    long a;
//    f(a);
// }
// Here, MSVC will call f(int) instead of generating a compile error
// as clang will do in standard mode.
if (S.getLangOpts().MSVCCompat &&
    !S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) &&
    SCS1.Second == ICK_Integral_Conversion &&
    SCS2.Second == ICK_Floating_Integral &&
    S.Context.getTypeSize(SCS1.getFromType()) ==
        S.Context.getTypeSize(SCS1.getToType(2)))
  return ImplicitConversionSequence::Better;

// Prefer a compatible vector conversion over a lax vector conversion
// For example:
//
// typedef float __v4sf __attribute__((__vector_size__(16)));
// void f(vector float);
// void f(vector signed int);
// int main() {
//   __v4sf a;
//   f(a);
// }
// Here, we'd like to choose f(vector float) and not
// report an ambiguous call error
if (SCS1.Second == ICK_Vector_Conversion &&
    SCS2.Second == ICK_Vector_Conversion) {
  bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
      SCS1.getFromType(), SCS1.getToType(2));
  bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
      SCS2.getFromType(), SCS2.getToType(2));

  if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
    return SCS1IsCompatibleVectorConversion
               ? ImplicitConversionSequence::Better
               : ImplicitConversionSequence::Worse;
}

if (SCS1.Second == ICK_SVE_Vector_Conversion &&
    SCS2.Second == ICK_SVE_Vector_Conversion) {
  bool SCS1IsCompatibleSVEVectorConversion =
      S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2));
  bool SCS2IsCompatibleSVEVectorConversion =
      S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2));

  if (SCS1IsCompatibleSVEVectorConversion !=
      SCS2IsCompatibleSVEVectorConversion)
    return SCS1IsCompatibleSVEVectorConversion
               ? ImplicitConversionSequence::Better
               : ImplicitConversionSequence::Worse;
}

return ImplicitConversionSequence::Indistinguishable;
4170}

4172/// CompareQualificationConversions - Compares two standard conversion
4173/// sequences to determine whether they can be ranked based on their
4174/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
4175static ImplicitConversionSequence::CompareKind
4176CompareQualificationConversions(Sema &S,
                              const StandardConversionSequence& SCS1,
                              const StandardConversionSequence& SCS2) {
// C++ 13.3.3.2p3:
//  -- S1 and S2 differ only in their qualification conversion and
//     yield similar types T1 and T2 (C++ 4.4), respectively, and the
//     cv-qualification signature of type T1 is a proper subset of
//     the cv-qualification signature of type T2, and S1 is not the
//     deprecated string literal array-to-pointer conversion (4.2).
if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
    SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
  return ImplicitConversionSequence::Indistinguishable;

// FIXME: the example in the standard doesn't use a qualification
// conversion (!)
QualType T1 = SCS1.getToType(2);
QualType T2 = SCS2.getToType(2);
T1 = S.Context.getCanonicalType(T1);
T2 = S.Context.getCanonicalType(T2);
assert(!T1->isReferenceType() && !T2->isReferenceType())((void)0);
Qualifiers T1Quals, T2Quals;
QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);

// If the types are the same, we won't learn anything by unwrapping
// them.
if (UnqualT1 == UnqualT2)
  return ImplicitConversionSequence::Indistinguishable;

ImplicitConversionSequence::CompareKind Result
  = ImplicitConversionSequence::Indistinguishable;

// Objective-C++ ARC:
//   Prefer qualification conversions not involving a change in lifetime
//   to qualification conversions that do not change lifetime.
if (SCS1.QualificationIncludesObjCLifetime !=
                                    SCS2.QualificationIncludesObjCLifetime) {
  Result = SCS1.QualificationIncludesObjCLifetime
             ? ImplicitConversionSequence::Worse
             : ImplicitConversionSequence::Better;
}

while (S.Context.UnwrapSimilarTypes(T1, T2)) {
  // Within each iteration of the loop, we check the qualifiers to
  // determine if this still looks like a qualification
  // conversion. Then, if all is well, we unwrap one more level of
  // pointers or pointers-to-members and do it all again
  // until there are no more pointers or pointers-to-members left
  // to unwrap. This essentially mimics what
  // IsQualificationConversion does, but here we're checking for a
  // strict subset of qualifiers.
  if (T1.getQualifiers().withoutObjCLifetime() ==
      T2.getQualifiers().withoutObjCLifetime())
    // The qualifiers are the same, so this doesn't tell us anything
    // about how the sequences rank.
    // ObjC ownership quals are omitted above as they interfere with
    // the ARC overload rule.
    ;
  else if (T2.isMoreQualifiedThan(T1)) {
    // T1 has fewer qualifiers, so it could be the better sequence.
    if (Result == ImplicitConversionSequence::Worse)
      // Neither has qualifiers that are a subset of the other's
      // qualifiers.
      return ImplicitConversionSequence::Indistinguishable;

    Result = ImplicitConversionSequence::Better;
  } else if (T1.isMoreQualifiedThan(T2)) {
    // T2 has fewer qualifiers, so it could be the better sequence.
    if (Result == ImplicitConversionSequence::Better)
      // Neither has qualifiers that are a subset of the other's
      // qualifiers.
      return ImplicitConversionSequence::Indistinguishable;

    Result = ImplicitConversionSequence::Worse;
  } else {
    // Qualifiers are disjoint.
    return ImplicitConversionSequence::Indistinguishable;
  }

  // If the types after this point are equivalent, we're done.
  if (S.Context.hasSameUnqualifiedType(T1, T2))
    break;
}

// Check that the winning standard conversion sequence isn't using
// the deprecated string literal array to pointer conversion.
switch (Result) {
case ImplicitConversionSequence::Better:
  if (SCS1.DeprecatedStringLiteralToCharPtr)
    Result = ImplicitConversionSequence::Indistinguishable;
  break;

case ImplicitConversionSequence::Indistinguishable:
  break;

case ImplicitConversionSequence::Worse:
  if (SCS2.DeprecatedStringLiteralToCharPtr)
    Result = ImplicitConversionSequence::Indistinguishable;
  break;
}

return Result;
4278}

4280/// CompareDerivedToBaseConversions - Compares two standard conversion
4281/// sequences to determine whether they can be ranked based on their
4282/// various kinds of derived-to-base conversions (C++
4283/// [over.ics.rank]p4b3).  As part of these checks, we also look at
4284/// conversions between Objective-C interface types.
4285static ImplicitConversionSequence::CompareKind
4286CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
                              const StandardConversionSequence& SCS1,
                              const StandardConversionSequence& SCS2) {
QualType FromType1 = SCS1.getFromType();
QualType ToType1 = SCS1.getToType(1);
QualType FromType2 = SCS2.getFromType();
QualType ToType2 = SCS2.getToType(1);

// Adjust the types we're converting from via the array-to-pointer
// conversion, if we need to.
if (SCS1.First == ICK_Array_To_Pointer)
  FromType1 = S.Context.getArrayDecayedType(FromType1);
if (SCS2.First == ICK_Array_To_Pointer)
  FromType2 = S.Context.getArrayDecayedType(FromType2);

// Canonicalize all of the types.
FromType1 = S.Context.getCanonicalType(FromType1);
ToType1 = S.Context.getCanonicalType(ToType1);
FromType2 = S.Context.getCanonicalType(FromType2);
ToType2 = S.Context.getCanonicalType(ToType2);

// C++ [over.ics.rank]p4b3:
//
//   If class B is derived directly or indirectly from class A and
//   class C is derived directly or indirectly from B,
//
// Compare based on pointer conversions.
if (SCS1.Second == ICK_Pointer_Conversion &&
    SCS2.Second == ICK_Pointer_Conversion &&
    /*FIXME: Remove if Objective-C id conversions get their own rank*/
    FromType1->isPointerType() && FromType2->isPointerType() &&
    ToType1->isPointerType() && ToType2->isPointerType()) {
  QualType FromPointee1 =
      FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
  QualType ToPointee1 =
      ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
  QualType FromPointee2 =
      FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
  QualType ToPointee2 =
      ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();

  //   -- conversion of C* to B* is better than conversion of C* to A*,
  if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
    if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
      return ImplicitConversionSequence::Better;
    else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
      return ImplicitConversionSequence::Worse;
  }

  //   -- conversion of B* to A* is better than conversion of C* to A*,
  if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
    if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
      return ImplicitConversionSequence::Better;
    else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
      return ImplicitConversionSequence::Worse;
  }
} else if (SCS1.Second == ICK_Pointer_Conversion &&
           SCS2.Second == ICK_Pointer_Conversion) {
  const ObjCObjectPointerType *FromPtr1
    = FromType1->getAs<ObjCObjectPointerType>();
  const ObjCObjectPointerType *FromPtr2
    = FromType2->getAs<ObjCObjectPointerType>();
  const ObjCObjectPointerType *ToPtr1
    = ToType1->getAs<ObjCObjectPointerType>();
  const ObjCObjectPointerType *ToPtr2
    = ToType2->getAs<ObjCObjectPointerType>();

  if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
    // Apply the same conversion ranking rules for Objective-C pointer types
    // that we do for C++ pointers to class types. However, we employ the
    // Objective-C pseudo-subtyping relationship used for assignment of
    // Objective-C pointer types.
    bool FromAssignLeft
      = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
    bool FromAssignRight
      = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
    bool ToAssignLeft
      = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
    bool ToAssignRight
      = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);

    // A conversion to an a non-id object pointer type or qualified 'id'
    // type is better than a conversion to 'id'.
    if (ToPtr1->isObjCIdType() &&
        (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
      return ImplicitConversionSequence::Worse;
    if (ToPtr2->isObjCIdType() &&
        (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
      return ImplicitConversionSequence::Better;

    // A conversion to a non-id object pointer type is better than a
    // conversion to a qualified 'id' type
    if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
      return ImplicitConversionSequence::Worse;
    if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
      return ImplicitConversionSequence::Better;

    // A conversion to an a non-Class object pointer type or qualified 'Class'
    // type is better than a conversion to 'Class'.
    if (ToPtr1->isObjCClassType() &&
        (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
      return ImplicitConversionSequence::Worse;
    if (ToPtr2->isObjCClassType() &&
        (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
      return ImplicitConversionSequence::Better;

    // A conversion to a non-Class object pointer type is better than a
    // conversion to a qualified 'Class' type.
    if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
      return ImplicitConversionSequence::Worse;
    if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
      return ImplicitConversionSequence::Better;

    //   -- "conversion of C* to B* is better than conversion of C* to A*,"
    if (S.Context.hasSameType(FromType1, FromType2) &&
        !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
        (ToAssignLeft != ToAssignRight)) {
      if (FromPtr1->isSpecialized()) {
        // "conversion of B<A> * to B * is better than conversion of B * to
        // C *.
        bool IsFirstSame =
            FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
        bool IsSecondSame =
            FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
        if (IsFirstSame) {
          if (!IsSecondSame)
            return ImplicitConversionSequence::Better;
        } else if (IsSecondSame)
          return ImplicitConversionSequence::Worse;
      }
      return ToAssignLeft? ImplicitConversionSequence::Worse
                         : ImplicitConversionSequence::Better;
    }

    //   -- "conversion of B* to A* is better than conversion of C* to A*,"
    if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
        (FromAssignLeft != FromAssignRight))
      return FromAssignLeft? ImplicitConversionSequence::Better
      : ImplicitConversionSequence::Worse;
  }
}

// Ranking of member-pointer types.
if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
    FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
    ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
  const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
  const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
  const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
  const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
  const Type *FromPointeeType1 = FromMemPointer1->getClass();
  const Type *ToPointeeType1 = ToMemPointer1->getClass();
  const Type *FromPointeeType2 = FromMemPointer2->getClass();
  const Type *ToPointeeType2 = ToMemPointer2->getClass();
  QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
  QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
  QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
  QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
  // conversion of A::* to B::* is better than conversion of A::* to C::*,
  if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
    if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
      return ImplicitConversionSequence::Worse;
    else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
      return ImplicitConversionSequence::Better;
  }
  // conversion of B::* to C::* is better than conversion of A::* to C::*
  if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
    if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
      return ImplicitConversionSequence::Better;
    else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
      return ImplicitConversionSequence::Worse;
  }
}

if (SCS1.Second == ICK_Derived_To_Base) {
  //   -- conversion of C to B is better than conversion of C to A,
  //   -- binding of an expression of type C to a reference of type
  //      B& is better than binding an expression of type C to a
  //      reference of type A&,
  if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
      !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
    if (S.IsDerivedFrom(Loc, ToType1, ToType2))
      return ImplicitConversionSequence::Better;
    else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
      return ImplicitConversionSequence::Worse;
  }

  //   -- conversion of B to A is better than conversion of C to A.
  //   -- binding of an expression of type B to a reference of type
  //      A& is better than binding an expression of type C to a
  //      reference of type A&,
  if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
      S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
    if (S.IsDerivedFrom(Loc, FromType2, FromType1))
      return ImplicitConversionSequence::Better;
    else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
      return ImplicitConversionSequence::Worse;
  }
}

return ImplicitConversionSequence::Indistinguishable;
4487}

4489/// Determine whether the given type is valid, e.g., it is not an invalid
4490/// C++ class.
4491static bool isTypeValid(QualType T) {
if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
  return !Record->isInvalidDecl();

return true;
4496}

4498static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
if (!T.getQualifiers().hasUnaligned())
  return T;

Qualifiers Q;
T = Ctx.getUnqualifiedArrayType(T, Q);
Q.removeUnaligned();
return Ctx.getQualifiedType(T, Q);
4506}

4508/// CompareReferenceRelationship - Compare the two types T1 and T2 to
4509/// determine whether they are reference-compatible,
4510/// reference-related, or incompatible, for use in C++ initialization by
4511/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
4512/// type, and the first type (T1) is the pointee type of the reference
4513/// type being initialized.
4514Sema::ReferenceCompareResult
4515Sema::CompareReferenceRelationship(SourceLocation Loc,
                                 QualType OrigT1, QualType OrigT2,
                                 ReferenceConversions *ConvOut) {
assert(!OrigT1->isReferenceType() &&((void)0)
  "T1 must be the pointee type of the reference type")((void)0);
assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type")((void)0);

QualType T1 = Context.getCanonicalType(OrigT1);
QualType T2 = Context.getCanonicalType(OrigT2);
Qualifiers T1Quals, T2Quals;
QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);

ReferenceConversions ConvTmp;
ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
Conv = ReferenceConversions();

// C++2a [dcl.init.ref]p4:
//   Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
//   reference-related to "cv2 T2" if T1 is similar to T2, or
//   T1 is a base class of T2.
//   "cv1 T1" is reference-compatible with "cv2 T2" if
//   a prvalue of type "pointer to cv2 T2" can be converted to the type
//   "pointer to cv1 T1" via a standard conversion sequence.

// Check for standard conversions we can apply to pointers: derived-to-base
// conversions, ObjC pointer conversions, and function pointer conversions.
// (Qualification conversions are checked last.)
QualType ConvertedT2;
if (UnqualT1 == UnqualT2) {
  // Nothing to do.
} else if (isCompleteType(Loc, OrigT2) &&
           isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
           IsDerivedFrom(Loc, UnqualT2, UnqualT1))
  Conv |= ReferenceConversions::DerivedToBase;
else if (UnqualT1->isObjCObjectOrInterfaceType() &&
         UnqualT2->isObjCObjectOrInterfaceType() &&
         Context.canBindObjCObjectType(UnqualT1, UnqualT2))
  Conv |= ReferenceConversions::ObjC;
else if (UnqualT2->isFunctionType() &&
         IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
  Conv |= ReferenceConversions::Function;
  // No need to check qualifiers; function types don't have them.
  return Ref_Compatible;
}
bool ConvertedReferent = Conv != 0;

// We can have a qualification conversion. Compute whether the types are
// similar at the same time.
bool PreviousToQualsIncludeConst = true;
bool TopLevel = true;
do {
  if (T1 == T2)
    break;

  // We will need a qualification conversion.
  Conv |= ReferenceConversions::Qualification;

  // Track whether we performed a qualification conversion anywhere other
  // than the top level. This matters for ranking reference bindings in
  // overload resolution.
  if (!TopLevel)
    Conv |= ReferenceConversions::NestedQualification;

  // MS compiler ignores __unaligned qualifier for references; do the same.
  T1 = withoutUnaligned(Context, T1);
  T2 = withoutUnaligned(Context, T2);

  // If we find a qualifier mismatch, the types are not reference-compatible,
  // but are still be reference-related if they're similar.
  bool ObjCLifetimeConversion = false;
  if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
                                     PreviousToQualsIncludeConst,
                                     ObjCLifetimeConversion))
    return (ConvertedReferent || Context.hasSimilarType(T1, T2))
               ? Ref_Related
               : Ref_Incompatible;

  // FIXME: Should we track this for any level other than the first?
  if (ObjCLifetimeConversion)
    Conv |= ReferenceConversions::ObjCLifetime;

  TopLevel = false;
} while (Context.UnwrapSimilarTypes(T1, T2));

// At this point, if the types are reference-related, we must either have the
// same inner type (ignoring qualifiers), or must have already worked out how
// to convert the referent.
return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
           ? Ref_Compatible
           : Ref_Incompatible;
4606}

4608/// Look for a user-defined conversion to a value reference-compatible
4609///        with DeclType. Return true if something definite is found.
4610static bool
4611FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
                       QualType DeclType, SourceLocation DeclLoc,
                       Expr *Init, QualType T2, bool AllowRvalues,
                       bool AllowExplicit) {
assert(T2->isRecordType() && "Can only find conversions of record types.")((void)0);
auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());

OverloadCandidateSet CandidateSet(
    DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
  NamedDecl *D = *I;
  CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
  if (isa<UsingShadowDecl>(D))
    D = cast<UsingShadowDecl>(D)->getTargetDecl();

  FunctionTemplateDecl *ConvTemplate
    = dyn_cast<FunctionTemplateDecl>(D);
  CXXConversionDecl *Conv;
  if (ConvTemplate)
    Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
  else
    Conv = cast<CXXConversionDecl>(D);

  if (AllowRvalues) {
    // If we are initializing an rvalue reference, don't permit conversion
    // functions that return lvalues.
    if (!ConvTemplate && DeclType->isRValueReferenceType()) {
      const ReferenceType *RefType
        = Conv->getConversionType()->getAs<LValueReferenceType>();
      if (RefType && !RefType->getPointeeType()->isFunctionType())
        continue;
    }

    if (!ConvTemplate &&
        S.CompareReferenceRelationship(
            DeclLoc,
            Conv->getConversionType()
                .getNonReferenceType()
                .getUnqualifiedType(),
            DeclType.getNonReferenceType().getUnqualifiedType()) ==
            Sema::Ref_Incompatible)
      continue;
  } else {
    // If the conversion function doesn't return a reference type,
    // it can't be considered for this conversion. An rvalue reference
    // is only acceptable if its referencee is a function type.

    const ReferenceType *RefType =
      Conv->getConversionType()->getAs<ReferenceType>();
    if (!RefType ||
        (!RefType->isLValueReferenceType() &&
         !RefType->getPointeeType()->isFunctionType()))
      continue;
  }

  if (ConvTemplate)
    S.AddTemplateConversionCandidate(
        ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
        /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
  else
    S.AddConversionCandidate(
        Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
        /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
}

bool HadMultipleCandidates = (CandidateSet.size() > 1);

OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
case OR_Success:
  // C++ [over.ics.ref]p1:
  //
  //   [...] If the parameter binds directly to the result of
  //   applying a conversion function to the argument
  //   expression, the implicit conversion sequence is a
  //   user-defined conversion sequence (13.3.3.1.2), with the
  //   second standard conversion sequence either an identity
  //   conversion or, if the conversion function returns an
  //   entity of a type that is a derived class of the parameter
  //   type, a derived-to-base Conversion.
  if (!Best->FinalConversion.DirectBinding)
    return false;

  ICS.setUserDefined();
  ICS.UserDefined.Before = Best->Conversions[0].Standard;
  ICS.UserDefined.After = Best->FinalConversion;
  ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
  ICS.UserDefined.ConversionFunction = Best->Function;
  ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
  ICS.UserDefined.EllipsisConversion = false;
  assert(ICS.UserDefined.After.ReferenceBinding &&((void)0)
         ICS.UserDefined.After.DirectBinding &&((void)0)
         "Expected a direct reference binding!")((void)0);
  return true;

case OR_Ambiguous:
  ICS.setAmbiguous();
  for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
       Cand != CandidateSet.end(); ++Cand)
    if (Cand->Best)
      ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
  return true;

case OR_No_Viable_Function:
case OR_Deleted:
  // There was no suitable conversion, or we found a deleted
  // conversion; continue with other checks.
  return false;
}

llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
4723}

4725/// Compute an implicit conversion sequence for reference
4726/// initialization.
4727static ImplicitConversionSequence
4728TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
               SourceLocation DeclLoc,
               bool SuppressUserConversions,
               bool AllowExplicit) {
assert(DeclType->isReferenceType() && "Reference init needs a reference")((void)0);

// Most paths end in a failed conversion.
ImplicitConversionSequence ICS;
ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);

QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
QualType T2 = Init->getType();

// If the initializer is the address of an overloaded function, try
// to resolve the overloaded function. If all goes well, T2 is the
// type of the resulting function.
if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
  DeclAccessPair Found;
  if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
                                                              false, Found))
    T2 = Fn->getType();
}

// Compute some basic properties of the types and the initializer.
bool isRValRef = DeclType->isRValueReferenceType();
Expr::Classification InitCategory = Init->Classify(S.Context);

Sema::ReferenceConversions RefConv;
Sema::ReferenceCompareResult RefRelationship =
    S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);

auto SetAsReferenceBinding = [&](bool BindsDirectly) {
  ICS.setStandard();
  ICS.Standard.First = ICK_Identity;
  // FIXME: A reference binding can be a function conversion too. We should
  // consider that when ordering reference-to-function bindings.
  ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
                            ? ICK_Derived_To_Base
                            : (RefConv & Sema::ReferenceConversions::ObjC)
                                  ? ICK_Compatible_Conversion
                                  : ICK_Identity;
  // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
  // a reference binding that performs a non-top-level qualification
  // conversion as a qualification conversion, not as an identity conversion.
  ICS.Standard.Third = (RefConv &
                            Sema::ReferenceConversions::NestedQualification)
                           ? ICK_Qualification
                           : ICK_Identity;
  ICS.Standard.setFromType(T2);
  ICS.Standard.setToType(0, T2);
  ICS.Standard.setToType(1, T1);
  ICS.Standard.setToType(2, T1);
  ICS.Standard.ReferenceBinding = true;
  ICS.Standard.DirectBinding = BindsDirectly;
  ICS.Standard.IsLvalueReference = !isRValRef;
  ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
  ICS.Standard.BindsToRvalue = InitCategory.isRValue();
  ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
  ICS.Standard.ObjCLifetimeConversionBinding =
      (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
  ICS.Standard.CopyConstructor = nullptr;
  ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
};

// C++0x [dcl.init.ref]p5:
//   A reference to type "cv1 T1" is initialized by an expression
//   of type "cv2 T2" as follows:

//     -- If reference is an lvalue reference and the initializer expression
if (!isRValRef) {
  //     -- is an lvalue (but is not a bit-field), and "cv1 T1" is
  //        reference-compatible with "cv2 T2," or
  //
  // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
  if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
    // C++ [over.ics.ref]p1:
    //   When a parameter of reference type binds directly (8.5.3)
    //   to an argument expression, the implicit conversion sequence
    //   is the identity conversion, unless the argument expression
    //   has a type that is a derived class of the parameter type,
    //   in which case the implicit conversion sequence is a
    //   derived-to-base Conversion (13.3.3.1).
    SetAsReferenceBinding(/*BindsDirectly=*/true);

    // Nothing more to do: the inaccessibility/ambiguity check for
    // derived-to-base conversions is suppressed when we're
    // computing the implicit conversion sequence (C++
    // [over.best.ics]p2).
    return ICS;
  }

  //       -- has a class type (i.e., T2 is a class type), where T1 is
  //          not reference-related to T2, and can be implicitly
  //          converted to an lvalue of type "cv3 T3," where "cv1 T1"
  //          is reference-compatible with "cv3 T3" 92) (this
  //          conversion is selected by enumerating the applicable
  //          conversion functions (13.3.1.6) and choosing the best
  //          one through overload resolution (13.3)),
  if (!SuppressUserConversions && T2->isRecordType() &&
      S.isCompleteType(DeclLoc, T2) &&
      RefRelationship == Sema::Ref_Incompatible) {
    if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
                                 Init, T2, /*AllowRvalues=*/false,
                                 AllowExplicit))
      return ICS;
  }
}

//     -- Otherwise, the reference shall be an lvalue reference to a
//        non-volatile const type (i.e., cv1 shall be const), or the reference
//        shall be an rvalue reference.
if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) {
  if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible)
    ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
  return ICS;
}

//       -- If the initializer expression
//
//            -- is an xvalue, class prvalue, array prvalue or function
//               lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
if (RefRelationship == Sema::Ref_Compatible &&
    (InitCategory.isXValue() ||
     (InitCategory.isPRValue() &&
        (T2->isRecordType() || T2->isArrayType())) ||
     (InitCategory.isLValue() && T2->isFunctionType()))) {
  // In C++11, this is always a direct binding. In C++98/03, it's a direct
  // binding unless we're binding to a class prvalue.
  // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
  // allow the use of rvalue references in C++98/03 for the benefit of
  // standard library implementors; therefore, we need the xvalue check here.
  SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
                        !(InitCategory.isPRValue() || T2->isRecordType()));
  return ICS;
}

//            -- has a class type (i.e., T2 is a class type), where T1 is not
//               reference-related to T2, and can be implicitly converted to
//               an xvalue, class prvalue, or function lvalue of type
//               "cv3 T3", where "cv1 T1" is reference-compatible with
//               "cv3 T3",
//
//          then the reference is bound to the value of the initializer
//          expression in the first case and to the result of the conversion
//          in the second case (or, in either case, to an appropriate base
//          class subobject).
if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
    T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
    FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
                             Init, T2, /*AllowRvalues=*/true,
                             AllowExplicit)) {
  // In the second case, if the reference is an rvalue reference
  // and the second standard conversion sequence of the
  // user-defined conversion sequence includes an lvalue-to-rvalue
  // conversion, the program is ill-formed.
  if (ICS.isUserDefined() && isRValRef &&
      ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
    ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);

  return ICS;
}

// A temporary of function type cannot be created; don't even try.
if (T1->isFunctionType())
  return ICS;

//       -- Otherwise, a temporary of type "cv1 T1" is created and
//          initialized from the initializer expression using the
//          rules for a non-reference copy initialization (8.5). The
//          reference is then bound to the temporary. If T1 is
//          reference-related to T2, cv1 must be the same
//          cv-qualification as, or greater cv-qualification than,
//          cv2; otherwise, the program is ill-formed.
if (RefRelationship == Sema::Ref_Related) {
  // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
  // we would be reference-compatible or reference-compatible with
  // added qualification. But that wasn't the case, so the reference
  // initialization fails.
  //
  // Note that we only want to check address spaces and cvr-qualifiers here.
  // ObjC GC, lifetime and unaligned qualifiers aren't important.
  Qualifiers T1Quals = T1.getQualifiers();
  Qualifiers T2Quals = T2.getQualifiers();
  T1Quals.removeObjCGCAttr();
  T1Quals.removeObjCLifetime();
  T2Quals.removeObjCGCAttr();
  T2Quals.removeObjCLifetime();
  // MS compiler ignores __unaligned qualifier for references; do the same.
  T1Quals.removeUnaligned();
  T2Quals.removeUnaligned();
  if (!T1Quals.compatiblyIncludes(T2Quals))
    return ICS;
}

// If at least one of the types is a class type, the types are not
// related, and we aren't allowed any user conversions, the
// reference binding fails. This case is important for breaking
// recursion, since TryImplicitConversion below will attempt to
// create a temporary through the use of a copy constructor.
if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
    (T1->isRecordType() || T2->isRecordType()))
  return ICS;

// If T1 is reference-related to T2 and the reference is an rvalue
// reference, the initializer expression shall not be an lvalue.
if (RefRelationship >= Sema::Ref_Related && isRValRef &&
    Init->Classify(S.Context).isLValue()) {
  ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType);
  return ICS;
}

// C++ [over.ics.ref]p2:
//   When a parameter of reference type is not bound directly to
//   an argument expression, the conversion sequence is the one
//   required to convert the argument expression to the
//   underlying type of the reference according to
//   13.3.3.1. Conceptually, this conversion sequence corresponds
//   to copy-initializing a temporary of the underlying type with
//   the argument expression. Any difference in top-level
//   cv-qualification is subsumed by the initialization itself
//   and does not constitute a conversion.
ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
                            AllowedExplicit::None,
                            /*InOverloadResolution=*/false,
                            /*CStyle=*/false,
                            /*AllowObjCWritebackConversion=*/false,
                            /*AllowObjCConversionOnExplicit=*/false);

// Of course, that's still a reference binding.
if (ICS.isStandard()) {
  ICS.Standard.ReferenceBinding = true;
  ICS.Standard.IsLvalueReference = !isRValRef;
  ICS.Standard.BindsToFunctionLvalue = false;
  ICS.Standard.BindsToRvalue = true;
  ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
  ICS.Standard.ObjCLifetimeConversionBinding = false;
} else if (ICS.isUserDefined()) {
  const ReferenceType *LValRefType =
      ICS.UserDefined.ConversionFunction->getReturnType()
          ->getAs<LValueReferenceType>();

  // C++ [over.ics.ref]p3:
  //   Except for an implicit object parameter, for which see 13.3.1, a
  //   standard conversion sequence cannot be formed if it requires [...]
  //   binding an rvalue reference to an lvalue other than a function
  //   lvalue.
  // Note that the function case is not possible here.
  if (isRValRef && LValRefType) {
    ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
    return ICS;
  }

  ICS.UserDefined.After.ReferenceBinding = true;
  ICS.UserDefined.After.IsLvalueReference = !isRValRef;
  ICS.UserDefined.After.BindsToFunctionLvalue = false;
  ICS.UserDefined.After.BindsToRvalue = !LValRefType;
  ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
  ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
}

return ICS;
4989}

4991static ImplicitConversionSequence
4992TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
                    bool SuppressUserConversions,
                    bool InOverloadResolution,
                    bool AllowObjCWritebackConversion,
                    bool AllowExplicit = false);

4998/// TryListConversion - Try to copy-initialize a value of type ToType from the
4999/// initializer list From.
5000static ImplicitConversionSequence
5001TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
                bool SuppressUserConversions,
                bool InOverloadResolution,
                bool AllowObjCWritebackConversion) {
// C++11 [over.ics.list]p1:
//   When an argument is an initializer list, it is not an expression and
//   special rules apply for converting it to a parameter type.

ImplicitConversionSequence Result;
Result.setBad(BadConversionSequence::no_conversion, From, ToType);

// We need a complete type for what follows. Incomplete types can never be
// initialized from init lists.
if (!S.isCompleteType(From->getBeginLoc(), ToType))
  return Result;

// Per DR1467:
//   If the parameter type is a class X and the initializer list has a single
//   element of type cv U, where U is X or a class derived from X, the
//   implicit conversion sequence is the one required to convert the element
//   to the parameter type.
//
//   Otherwise, if the parameter type is a character array [... ]
//   and the initializer list has a single element that is an
//   appropriately-typed string literal (8.5.2 [dcl.init.string]), the
//   implicit conversion sequence is the identity conversion.
if (From->getNumInits() == 1) {
  if (ToType->isRecordType()) {
    QualType InitType = From->getInit(0)->getType();
    if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
        S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
      return TryCopyInitialization(S, From->getInit(0), ToType,
                                   SuppressUserConversions,
                                   InOverloadResolution,
                                   AllowObjCWritebackConversion);
  }

  if (const auto *AT = S.Context.getAsArrayType(ToType)) {
    if (S.IsStringInit(From->getInit(0), AT)) {
      InitializedEntity Entity =
        InitializedEntity::InitializeParameter(S.Context, ToType,
                                               /*Consumed=*/false);
      if (S.CanPerformCopyInitialization(Entity, From)) {
        Result.setStandard();
        Result.Standard.setAsIdentityConversion();
        Result.Standard.setFromType(ToType);
        Result.Standard.setAllToTypes(ToType);
        return Result;
      }
    }
  }
}

// C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
// C++11 [over.ics.list]p2:
//   If the parameter type is std::initializer_list<X> or "array of X" and
//   all the elements can be implicitly converted to X, the implicit
//   conversion sequence is the worst conversion necessary to convert an
//   element of the list to X.
//
// C++14 [over.ics.list]p3:
//   Otherwise, if the parameter type is "array of N X", if the initializer
//   list has exactly N elements or if it has fewer than N elements and X is
//   default-constructible, and if all the elements of the initializer list
//   can be implicitly converted to X, the implicit conversion sequence is
//   the worst conversion necessary to convert an element of the list to X.
//
// FIXME: We're missing a lot of these checks.
bool toStdInitializerList = false;
QualType X;
if (ToType->isArrayType())
  X = S.Context.getAsArrayType(ToType)->getElementType();
else
  toStdInitializerList = S.isStdInitializerList(ToType, &X);
if (!X.isNull()) {
  for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) {
    Expr *Init = From->getInit(i);
    ImplicitConversionSequence ICS =
        TryCopyInitialization(S, Init, X, SuppressUserConversions,
                              InOverloadResolution,
                              AllowObjCWritebackConversion);
    // If a single element isn't convertible, fail.
    if (ICS.isBad()) {
      Result = ICS;
      break;
    }
    // Otherwise, look for the worst conversion.
    if (Result.isBad() || CompareImplicitConversionSequences(
                              S, From->getBeginLoc(), ICS, Result) ==
                              ImplicitConversionSequence::Worse)
      Result = ICS;
  }

  // For an empty list, we won't have computed any conversion sequence.
  // Introduce the identity conversion sequence.
  if (From->getNumInits() == 0) {
    Result.setStandard();
    Result.Standard.setAsIdentityConversion();
    Result.Standard.setFromType(ToType);
    Result.Standard.setAllToTypes(ToType);
  }

  Result.setStdInitializerListElement(toStdInitializerList);
  return Result;
}

// C++14 [over.ics.list]p4:
// C++11 [over.ics.list]p3:
//   Otherwise, if the parameter is a non-aggregate class X and overload
//   resolution chooses a single best constructor [...] the implicit
//   conversion sequence is a user-defined conversion sequence. If multiple
//   constructors are viable but none is better than the others, the
//   implicit conversion sequence is a user-defined conversion sequence.
if (ToType->isRecordType() && !ToType->isAggregateType()) {
  // This function can deal with initializer lists.
  return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
                                  AllowedExplicit::None,
                                  InOverloadResolution, /*CStyle=*/false,
                                  AllowObjCWritebackConversion,
                                  /*AllowObjCConversionOnExplicit=*/false);
}

// C++14 [over.ics.list]p5:
// C++11 [over.ics.list]p4:
//   Otherwise, if the parameter has an aggregate type which can be
//   initialized from the initializer list [...] the implicit conversion
//   sequence is a user-defined conversion sequence.
if (ToType->isAggregateType()) {
  // Type is an aggregate, argument is an init list. At this point it comes
  // down to checking whether the initialization works.
  // FIXME: Find out whether this parameter is consumed or not.
  InitializedEntity Entity =
      InitializedEntity::InitializeParameter(S.Context, ToType,
                                             /*Consumed=*/false);
  if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
                                                               From)) {
    Result.setUserDefined();
    Result.UserDefined.Before.setAsIdentityConversion();
    // Initializer lists don't have a type.
    Result.UserDefined.Before.setFromType(QualType());
    Result.UserDefined.Before.setAllToTypes(QualType());

    Result.UserDefined.After.setAsIdentityConversion();
    Result.UserDefined.After.setFromType(ToType);
    Result.UserDefined.After.setAllToTypes(ToType);
    Result.UserDefined.ConversionFunction = nullptr;
  }
  return Result;
}

// C++14 [over.ics.list]p6:
// C++11 [over.ics.list]p5:
//   Otherwise, if the parameter is a reference, see 13.3.3.1.4.
if (ToType->isReferenceType()) {
  // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
  // mention initializer lists in any way. So we go by what list-
  // initialization would do and try to extrapolate from that.

  QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();

  // If the initializer list has a single element that is reference-related
  // to the parameter type, we initialize the reference from that.
  if (From->getNumInits() == 1) {
    Expr *Init = From->getInit(0);

    QualType T2 = Init->getType();

    // If the initializer is the address of an overloaded function, try
    // to resolve the overloaded function. If all goes well, T2 is the
    // type of the resulting function.
    if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
      DeclAccessPair Found;
      if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
                                 Init, ToType, false, Found))
        T2 = Fn->getType();
    }

    // Compute some basic properties of the types and the initializer.
    Sema::ReferenceCompareResult RefRelationship =
        S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);

    if (RefRelationship >= Sema::Ref_Related) {
      return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
                              SuppressUserConversions,
                              /*AllowExplicit=*/false);
    }
  }

  // Otherwise, we bind the reference to a temporary created from the
  // initializer list.
  Result = TryListConversion(S, From, T1, SuppressUserConversions,
                             InOverloadResolution,
                             AllowObjCWritebackConversion);
  if (Result.isFailure())
    return Result;
  assert(!Result.isEllipsis() &&((void)0)
         "Sub-initialization cannot result in ellipsis conversion.")((void)0);

  // Can we even bind to a temporary?
  if (ToType->isRValueReferenceType() ||
      (T1.isConstQualified() && !T1.isVolatileQualified())) {
    StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
                                          Result.UserDefined.After;
    SCS.ReferenceBinding = true;
    SCS.IsLvalueReference = ToType->isLValueReferenceType();
    SCS.BindsToRvalue = true;
    SCS.BindsToFunctionLvalue = false;
    SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
    SCS.ObjCLifetimeConversionBinding = false;
  } else
    Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
                  From, ToType);
  return Result;
}

// C++14 [over.ics.list]p7:
// C++11 [over.ics.list]p6:
//   Otherwise, if the parameter type is not a class:
if (!ToType->isRecordType()) {
  //    - if the initializer list has one element that is not itself an
  //      initializer list, the implicit conversion sequence is the one
  //      required to convert the element to the parameter type.
  unsigned NumInits = From->getNumInits();
  if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
    Result = TryCopyInitialization(S, From->getInit(0), ToType,
                                   SuppressUserConversions,
                                   InOverloadResolution,
                                   AllowObjCWritebackConversion);
  //    - if the initializer list has no elements, the implicit conversion
  //      sequence is the identity conversion.
  else if (NumInits == 0) {
    Result.setStandard();
    Result.Standard.setAsIdentityConversion();
    Result.Standard.setFromType(ToType);
    Result.Standard.setAllToTypes(ToType);
  }
  return Result;
}

// C++14 [over.ics.list]p8:
// C++11 [over.ics.list]p7:
//   In all cases other than those enumerated above, no conversion is possible
return Result;
5244}

5246/// TryCopyInitialization - Try to copy-initialize a value of type
5247/// ToType from the expression From. Return the implicit conversion
5248/// sequence required to pass this argument, which may be a bad
5249/// conversion sequence (meaning that the argument cannot be passed to
5250/// a parameter of this type). If @p SuppressUserConversions, then we
5251/// do not permit any user-defined conversion sequences.
5252static ImplicitConversionSequence
5253TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
                    bool SuppressUserConversions,
                    bool InOverloadResolution,
                    bool AllowObjCWritebackConversion,
                    bool AllowExplicit) {
if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
  return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
                           InOverloadResolution,AllowObjCWritebackConversion);

if (ToType->isReferenceType())
  return TryReferenceInit(S, From, ToType,
                          /*FIXME:*/ From->getBeginLoc(),
                          SuppressUserConversions, AllowExplicit);

return TryImplicitConversion(S, From, ToType,
                             SuppressUserConversions,
                             AllowedExplicit::None,
                             InOverloadResolution,
                             /*CStyle=*/false,
                             AllowObjCWritebackConversion,
                             /*AllowObjCConversionOnExplicit=*/false);
5274}

5276static bool TryCopyInitialization(const CanQualType FromQTy,
                                const CanQualType ToQTy,
                                Sema &S,
                                SourceLocation Loc,
                                ExprValueKind FromVK) {
OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
ImplicitConversionSequence ICS =
  TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);

return !ICS.isBad();
5286}

5288/// TryObjectArgumentInitialization - Try to initialize the object
5289/// parameter of the given member function (@c Method) from the
5290/// expression @p From.
5291static ImplicitConversionSequence
5292TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
                              Expr::Classification FromClassification,
                              CXXMethodDecl *Method,
                              CXXRecordDecl *ActingContext) {
QualType ClassType = S.Context.getTypeDeclType(ActingContext);
// [class.dtor]p2: A destructor can be invoked for a const, volatile or
//                 const volatile object.
Qualifiers Quals = Method->getMethodQualifiers();
if (isa<CXXDestructorDecl>(Method)) {
  Quals.addConst();
  Quals.addVolatile();
}

QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);

// Set up the conversion sequence as a "bad" conversion, to allow us
// to exit early.
ImplicitConversionSequence ICS;

// We need to have an object of class type.
if (const PointerType *PT = FromType->getAs<PointerType>()) {
  FromType = PT->getPointeeType();

  // When we had a pointer, it's implicitly dereferenced, so we
  // better have an lvalue.
  assert(FromClassification.isLValue())((void)0);
}

assert(FromType->isRecordType())((void)0);

// C++0x [over.match.funcs]p4:
//   For non-static member functions, the type of the implicit object
//   parameter is
//
//     - "lvalue reference to cv X" for functions declared without a
//        ref-qualifier or with the & ref-qualifier
//     - "rvalue reference to cv X" for functions declared with the &&
//        ref-qualifier
//
// where X is the class of which the function is a member and cv is the
// cv-qualification on the member function declaration.
//
// However, when finding an implicit conversion sequence for the argument, we
// are not allowed to perform user-defined conversions
// (C++ [over.match.funcs]p5). We perform a simplified version of
// reference binding here, that allows class rvalues to bind to
// non-constant references.

// First check the qualifiers.
QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
if (ImplicitParamType.getCVRQualifiers()
                                  != FromTypeCanon.getLocalCVRQualifiers() &&
    !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
  ICS.setBad(BadConversionSequence::bad_qualifiers,
             FromType, ImplicitParamType);
  return ICS;
}

if (FromTypeCanon.hasAddressSpace()) {
  Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
  Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
  if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
    ICS.setBad(BadConversionSequence::bad_qualifiers,
               FromType, ImplicitParamType);
    return ICS;
  }
}

// Check that we have either the same type or a derived type. It
// affects the conversion rank.
QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
ImplicitConversionKind SecondKind;
if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
  SecondKind = ICK_Identity;
} else if (S.IsDerivedFrom(Loc, FromType, ClassType))
  SecondKind = ICK_Derived_To_Base;
else {
  ICS.setBad(BadConversionSequence::unrelated_class,
             FromType, ImplicitParamType);
  return ICS;
}

// Check the ref-qualifier.
switch (Method->getRefQualifier()) {
case RQ_None:
  // Do nothing; we don't care about lvalueness or rvalueness.
  break;

case RQ_LValue:
  if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
    // non-const lvalue reference cannot bind to an rvalue
    ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
               ImplicitParamType);
    return ICS;
  }
  break;

case RQ_RValue:
  if (!FromClassification.isRValue()) {
    // rvalue reference cannot bind to an lvalue
    ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
               ImplicitParamType);
    return ICS;
  }
  break;
}

// Success. Mark this as a reference binding.
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
ICS.Standard.Second = SecondKind;
ICS.Standard.setFromType(FromType);
ICS.Standard.setAllToTypes(ImplicitParamType);
ICS.Standard.ReferenceBinding = true;
ICS.Standard.DirectBinding = true;
ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
ICS.Standard.BindsToFunctionLvalue = false;
ICS.Standard.BindsToRvalue = FromClassification.isRValue();
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
  = (Method->getRefQualifier() == RQ_None);
return ICS;
5413}

5415/// PerformObjectArgumentInitialization - Perform initialization of
5416/// the implicit object parameter for the given Method with the given
5417/// expression.
5418ExprResult
5419Sema::PerformObjectArgumentInitialization(Expr *From,
                                        NestedNameSpecifier *Qualifier,
                                        NamedDecl *FoundDecl,
                                        CXXMethodDecl *Method) {
QualType FromRecordType, DestType;
QualType ImplicitParamRecordType  =
  Method->getThisType()->castAs<PointerType>()->getPointeeType();

Expr::Classification FromClassification;
if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
  FromRecordType = PT->getPointeeType();
  DestType = Method->getThisType();
  FromClassification = Expr::Classification::makeSimpleLValue();
} else {
  FromRecordType = From->getType();
  DestType = ImplicitParamRecordType;
  FromClassification = From->Classify(Context);

  // When performing member access on a prvalue, materialize a temporary.
  if (From->isPRValue()) {
    From = CreateMaterializeTemporaryExpr(FromRecordType, From,
                                          Method->getRefQualifier() !=
                                              RefQualifierKind::RQ_RValue);
  }
}

// Note that we always use the true parent context when performing
// the actual argument initialization.
ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
    *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
    Method->getParent());
if (ICS.isBad()) {
  switch (ICS.Bad.Kind) {
  case BadConversionSequence::bad_qualifiers: {
    Qualifiers FromQs = FromRecordType.getQualifiers();
    Qualifiers ToQs = DestType.getQualifiers();
    unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
    if (CVR) {
      Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
          << Method->getDeclName() << FromRecordType << (CVR - 1)
          << From->getSourceRange();
      Diag(Method->getLocation(), diag::note_previous_decl)
        << Method->getDeclName();
      return ExprError();
    }
    break;
  }

  case BadConversionSequence::lvalue_ref_to_rvalue:
  case BadConversionSequence::rvalue_ref_to_lvalue: {
    bool IsRValueQualified =
      Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
    Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
        << Method->getDeclName() << FromClassification.isRValue()
        << IsRValueQualified;
    Diag(Method->getLocation(), diag::note_previous_decl)
      << Method->getDeclName();
    return ExprError();
  }

  case BadConversionSequence::no_conversion:
  case BadConversionSequence::unrelated_class:
    break;
  }

  return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
         << ImplicitParamRecordType << FromRecordType
         << From->getSourceRange();
}

if (ICS.Standard.Second == ICK_Derived_To_Base) {
  ExprResult FromRes =
    PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
  if (FromRes.isInvalid())
    return ExprError();
  From = FromRes.get();
}

if (!Context.hasSameType(From->getType(), DestType)) {
  CastKind CK;
  QualType PteeTy = DestType->getPointeeType();
  LangAS DestAS =
      PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
  if (FromRecordType.getAddressSpace() != DestAS)
    CK = CK_AddressSpaceConversion;
  else
    CK = CK_NoOp;
  From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
}
return From;
5509}

5511/// TryContextuallyConvertToBool - Attempt to contextually convert the
5512/// expression From to bool (C++0x [conv]p3).
5513static ImplicitConversionSequence
5514TryContextuallyConvertToBool(Sema &S, Expr *From) {
// C++ [dcl.init]/17.8:
//   - Otherwise, if the initialization is direct-initialization, the source
//     type is std::nullptr_t, and the destination type is bool, the initial
//     value of the object being initialized is false.
if (From->getType()->isNullPtrType())
  return ImplicitConversionSequence::getNullptrToBool(From->getType(),
                                                      S.Context.BoolTy,
                                                      From->isGLValue());

// All other direct-initialization of bool is equivalent to an implicit
// conversion to bool in which explicit conversions are permitted.
return TryImplicitConversion(S, From, S.Context.BoolTy,
                             /*SuppressUserConversions=*/false,
                             AllowedExplicit::Conversions,
                             /*InOverloadResolution=*/false,
                             /*CStyle=*/false,
                             /*AllowObjCWritebackConversion=*/false,
                             /*AllowObjCConversionOnExplicit=*/false);
5533}

5535/// PerformContextuallyConvertToBool - Perform a contextual conversion
5536/// of the expression From to bool (C++0x [conv]p3).
5537ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
if (checkPlaceholderForOverload(*this, From))
  return ExprError();

ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
if (!ICS.isBad())
  return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);

if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
  return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
         << From->getType() << From->getSourceRange();
return ExprError();
5549}

5551/// Check that the specified conversion is permitted in a converted constant
5552/// expression, according to C++11 [expr.const]p3. Return true if the conversion
5553/// is acceptable.
5554static bool CheckConvertedConstantConversions(Sema &S,
                                            StandardConversionSequence &SCS) {
// Since we know that the target type is an integral or unscoped enumeration
// type, most conversion kinds are impossible. All possible First and Third
// conversions are fine.
switch (SCS.Second) {
case ICK_Identity:
case ICK_Integral_Promotion:
case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
case ICK_Zero_Queue_Conversion:
  return true;

case ICK_Boolean_Conversion:
  // Conversion from an integral or unscoped enumeration type to bool is
  // classified as ICK_Boolean_Conversion, but it's also arguably an integral
  // conversion, so we allow it in a converted constant expression.
  //
  // FIXME: Per core issue 1407, we should not allow this, but that breaks
  // a lot of popular code. We should at least add a warning for this
  // (non-conforming) extension.
  return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
         SCS.getToType(2)->isBooleanType();

case ICK_Pointer_Conversion:
case ICK_Pointer_Member:
  // C++1z: null pointer conversions and null member pointer conversions are
  // only permitted if the source type is std::nullptr_t.
  return SCS.getFromType()->isNullPtrType();

case ICK_Floating_Promotion:
case ICK_Complex_Promotion:
case ICK_Floating_Conversion:
case ICK_Complex_Conversion:
case ICK_Floating_Integral:
case ICK_Compatible_Conversion:
case ICK_Derived_To_Base:
case ICK_Vector_Conversion:
case ICK_SVE_Vector_Conversion:
case ICK_Vector_Splat:
case ICK_Complex_Real:
case ICK_Block_Pointer_Conversion:
case ICK_TransparentUnionConversion:
case ICK_Writeback_Conversion:
case ICK_Zero_Event_Conversion:
case ICK_C_Only_Conversion:
case ICK_Incompatible_Pointer_Conversion:
  return false;

case ICK_Lvalue_To_Rvalue:
case ICK_Array_To_Pointer:
case ICK_Function_To_Pointer:
  llvm_unreachable("found a first conversion kind in Second")__builtin_unreachable();

case ICK_Function_Conversion:
case ICK_Qualification:
  llvm_unreachable("found a third conversion kind in Second")__builtin_unreachable();

case ICK_Num_Conversion_Kinds:
  break;
}

llvm_unreachable("unknown conversion kind")__builtin_unreachable();
5616}

5618/// CheckConvertedConstantExpression - Check that the expression From is a
5619/// converted constant expression of type T, perform the conversion and produce
5620/// the converted expression, per C++11 [expr.const]p3.
5621static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
                                                 QualType T, APValue &Value,
                                                 Sema::CCEKind CCE,
                                                 bool RequireInt,
                                                 NamedDecl *Dest) {
assert(S.getLangOpts().CPlusPlus11 &&((void)0)
       "converted constant expression outside C++11")((void)0);

if (checkPlaceholderForOverload(S, From))
  return ExprError();

// C++1z [expr.const]p3:
//  A converted constant expression of type T is an expression,
//  implicitly converted to type T, where the converted
//  expression is a constant expression and the implicit conversion
//  sequence contains only [... list of conversions ...].
ImplicitConversionSequence ICS =
    CCE == Sema::CCEK_ExplicitBool
        ? TryContextuallyConvertToBool(S, From)
        : TryCopyInitialization(S, From, T,
                                /*SuppressUserConversions=*/false,
                                /*InOverloadResolution=*/false,
                                /*AllowObjCWritebackConversion=*/false,
                                /*AllowExplicit=*/false);
StandardConversionSequence *SCS = nullptr;
switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
  SCS = &ICS.Standard;
  break;
case ImplicitConversionSequence::UserDefinedConversion:
  if (T->isRecordType())
    SCS = &ICS.UserDefined.Before;
  else
    SCS = &ICS.UserDefined.After;
  break;
case ImplicitConversionSequence::AmbiguousConversion:
case ImplicitConversionSequence::BadConversion:
  if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
    return S.Diag(From->getBeginLoc(),
                  diag::err_typecheck_converted_constant_expression)
           << From->getType() << From->getSourceRange() << T;
  return ExprError();

case ImplicitConversionSequence::EllipsisConversion:
  llvm_unreachable("ellipsis conversion in converted constant expression")__builtin_unreachable();
}

// Check that we would only use permitted conversions.
if (!CheckConvertedConstantConversions(S, *SCS)) {
  return S.Diag(From->getBeginLoc(),
                diag::err_typecheck_converted_constant_expression_disallowed)
         << From->getType() << From->getSourceRange() << T;
}
// [...] and where the reference binding (if any) binds directly.
if (SCS->ReferenceBinding && !SCS->DirectBinding) {
  return S.Diag(From->getBeginLoc(),
                diag::err_typecheck_converted_constant_expression_indirect)
         << From->getType() << From->getSourceRange() << T;
}

// Usually we can simply apply the ImplicitConversionSequence we formed
// earlier, but that's not guaranteed to work when initializing an object of
// class type.
ExprResult Result;
if (T->isRecordType()) {
  assert(CCE == Sema::CCEK_TemplateArg &&((void)0)
         "unexpected class type converted constant expr")((void)0);
  Result = S.PerformCopyInitialization(
      InitializedEntity::InitializeTemplateParameter(
          T, cast<NonTypeTemplateParmDecl>(Dest)),
      SourceLocation(), From);
} else {
  Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
}
if (Result.isInvalid())
  return Result;

// C++2a [intro.execution]p5:
//   A full-expression is [...] a constant-expression [...]
Result =
    S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
                          /*DiscardedValue=*/false, /*IsConstexpr=*/true);
if (Result.isInvalid())
  return Result;

// Check for a narrowing implicit conversion.
bool ReturnPreNarrowingValue = false;
APValue PreNarrowingValue;
QualType PreNarrowingType;
switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
                              PreNarrowingType)) {
case NK_Dependent_Narrowing:
  // Implicit conversion to a narrower type, but the expression is
  // value-dependent so we can't tell whether it's actually narrowing.
case NK_Variable_Narrowing:
  // Implicit conversion to a narrower type, and the value is not a constant
  // expression. We'll diagnose this in a moment.
case NK_Not_Narrowing:
  break;

case NK_Constant_Narrowing:
  if (CCE == Sema::CCEK_ArrayBound &&
      PreNarrowingType->isIntegralOrEnumerationType() &&
      PreNarrowingValue.isInt()) {
    // Don't diagnose array bound narrowing here; we produce more precise
    // errors by allowing the un-narrowed value through.
    ReturnPreNarrowingValue = true;
    break;
  }
  S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
      << CCE << /*Constant*/ 1
      << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
  break;

case NK_Type_Narrowing:
  // FIXME: It would be better to diagnose that the expression is not a
  // constant expression.
  S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
      << CCE << /*Constant*/ 0 << From->getType() << T;
  break;
}

if (Result.get()->isValueDependent()) {
  Value = APValue();
  return Result;
}

// Check the expression is a constant expression.
SmallVector<PartialDiagnosticAt, 8> Notes;
Expr::EvalResult Eval;
Eval.Diag = &Notes;

ConstantExprKind Kind;
if (CCE == Sema::CCEK_TemplateArg && T->isRecordType())
  Kind = ConstantExprKind::ClassTemplateArgument;
else if (CCE == Sema::CCEK_TemplateArg)
  Kind = ConstantExprKind::NonClassTemplateArgument;
else
  Kind = ConstantExprKind::Normal;

if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) ||
    (RequireInt && !Eval.Val.isInt())) {
  // The expression can't be folded, so we can't keep it at this position in
  // the AST.
  Result = ExprError();
} else {
  Value = Eval.Val;

  if (Notes.empty()) {
    // It's a constant expression.
    Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value);
    if (ReturnPreNarrowingValue)
      Value = std::move(PreNarrowingValue);
    return E;
  }
}

// It's not a constant expression. Produce an appropriate diagnostic.
if (Notes.size() == 1 &&
    Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) {
  S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
} else if (!Notes.empty() && Notes[0].second.getDiagID() ==
                                 diag::note_constexpr_invalid_template_arg) {
  Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg);
  for (unsigned I = 0; I < Notes.size(); ++I)
    S.Diag(Notes[I].first, Notes[I].second);
} else {
  S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
      << CCE << From->getSourceRange();
  for (unsigned I = 0; I < Notes.size(); ++I)
    S.Diag(Notes[I].first, Notes[I].second);
}
return ExprError();
5794}

5796ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
                                                APValue &Value, CCEKind CCE,
                                                NamedDecl *Dest) {
return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false,
                                          Dest);
5801}

5803ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
                                                llvm::APSInt &Value,
                                                CCEKind CCE) {
assert(T->isIntegralOrEnumerationType() && "unexpected converted const type")((void)0);

APValue V;
auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true,
                                            /*Dest=*/nullptr);
if (!R.isInvalid() && !R.get()->isValueDependent())
  Value = V.getInt();
return R;
5814}


5817/// dropPointerConversions - If the given standard conversion sequence
5818/// involves any pointer conversions, remove them.  This may change
5819/// the result type of the conversion sequence.
5820static void dropPointerConversion(StandardConversionSequence &SCS) {
if (SCS.Second == ICK_Pointer_Conversion) {
  SCS.Second = ICK_Identity;
  SCS.Third = ICK_Identity;
  SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
}
5826}

5828/// TryContextuallyConvertToObjCPointer - Attempt to contextually
5829/// convert the expression From to an Objective-C pointer type.
5830static ImplicitConversionSequence
5831TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
// Do an implicit conversion to 'id'.
QualType Ty = S.Context.getObjCIdType();
ImplicitConversionSequence ICS
  = TryImplicitConversion(S, From, Ty,
                          // FIXME: Are these flags correct?
                          /*SuppressUserConversions=*/false,
                          AllowedExplicit::Conversions,
                          /*InOverloadResolution=*/false,
                          /*CStyle=*/false,
                          /*AllowObjCWritebackConversion=*/false,
                          /*AllowObjCConversionOnExplicit=*/true);

// Strip off any final conversions to 'id'.
switch (ICS.getKind()) {
case ImplicitConversionSequence::BadConversion:
case ImplicitConversionSequence::AmbiguousConversion:
case ImplicitConversionSequence::EllipsisConversion:
  break;

case ImplicitConversionSequence::UserDefinedConversion:
  dropPointerConversion(ICS.UserDefined.After);
  break;

case ImplicitConversionSequence::StandardConversion:
  dropPointerConversion(ICS.Standard);
  break;
}

return ICS;
5861}

5863/// PerformContextuallyConvertToObjCPointer - Perform a contextual
5864/// conversion of the expression From to an Objective-C pointer type.
5865/// Returns a valid but null ExprResult if no conversion sequence exists.
5866ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
if (checkPlaceholderForOverload(*this, From))
  return ExprError();

QualType Ty = Context.getObjCIdType();
ImplicitConversionSequence ICS =
  TryContextuallyConvertToObjCPointer(*this, From);
if (!ICS.isBad())
  return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
return ExprResult();
5876}

5878/// Determine whether the provided type is an integral type, or an enumeration
5879/// type of a permitted flavor.
5880bool Sema::ICEConvertDiagnoser::match(QualType T) {
return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
                               : T->isIntegralOrUnscopedEnumerationType();
5883}

5885static ExprResult
5886diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
                          Sema::ContextualImplicitConverter &Converter,
                          QualType T, UnresolvedSetImpl &ViableConversions) {

if (Converter.Suppress)
  return ExprError();

Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
  CXXConversionDecl *Conv =
      cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
  QualType ConvTy = Conv->getConversionType().getNonReferenceType();
  Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
}
return From;
5901}

5903static bool
5904diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
                         Sema::ContextualImplicitConverter &Converter,
                         QualType T, bool HadMultipleCandidates,
                         UnresolvedSetImpl &ExplicitConversions) {
if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
  DeclAccessPair Found = ExplicitConversions[0];
  CXXConversionDecl *Conversion =
      cast<CXXConversionDecl>(Found->getUnderlyingDecl());

  // The user probably meant to invoke the given explicit
  // conversion; use it.
  QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
  std::string TypeStr;
  ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());

  Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
      << FixItHint::CreateInsertion(From->getBeginLoc(),
                                    "static_cast<" + TypeStr + ">(")
      << FixItHint::CreateInsertion(
             SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
  Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);

  // If we aren't in a SFINAE context, build a call to the
  // explicit conversion function.
  if (SemaRef.isSFINAEContext())
    return true;

  SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
  ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
                                                     HadMultipleCandidates);
  if (Result.isInvalid())
    return true;
  // Record usage of conversion in an implicit cast.
  From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
                                  CK_UserDefinedConversion, Result.get(),
                                  nullptr, Result.get()->getValueKind(),
                                  SemaRef.CurFPFeatureOverrides());
}
return false;
5943}

5945static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
                           Sema::ContextualImplicitConverter &Converter,
                           QualType T, bool HadMultipleCandidates,
                           DeclAccessPair &Found) {
CXXConversionDecl *Conversion =
    cast<CXXConversionDecl>(Found->getUnderlyingDecl());
SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);

QualType ToType = Conversion->getConversionType().getNonReferenceType();
if (!Converter.SuppressConversion) {
  if (SemaRef.isSFINAEContext())
    return true;

  Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
      << From->getSourceRange();
}

ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
                                                   HadMultipleCandidates);
if (Result.isInvalid())
  return true;
// Record usage of conversion in an implicit cast.
From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
                                CK_UserDefinedConversion, Result.get(),
                                nullptr, Result.get()->getValueKind(),
                                SemaRef.CurFPFeatureOverrides());
return false;
5972}

5974static ExprResult finishContextualImplicitConversion(
  Sema &SemaRef, SourceLocation Loc, Expr *From,
  Sema::ContextualImplicitConverter &Converter) {
if (!Converter.match(From->getType()) && !Converter.Suppress)
  Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
      << From->getSourceRange();

return SemaRef.DefaultLvalueConversion(From);
5982}

5984static void
5985collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
                                UnresolvedSetImpl &ViableConversions,
                                OverloadCandidateSet &CandidateSet) {
for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
  DeclAccessPair FoundDecl = ViableConversions[I];
  NamedDecl *D = FoundDecl.getDecl();
  CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
  if (isa<UsingShadowDecl>(D))
    D = cast<UsingShadowDecl>(D)->getTargetDecl();

  CXXConversionDecl *Conv;
  FunctionTemplateDecl *ConvTemplate;
  if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
    Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
  else
    Conv = cast<CXXConversionDecl>(D);

  if (ConvTemplate)
    SemaRef.AddTemplateConversionCandidate(
        ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
        /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true);
  else
    SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
                                   ToType, CandidateSet,
                                   /*AllowObjCConversionOnExplicit=*/false,
                                   /*AllowExplicit*/ true);
}
6012}

6014/// Attempt to convert the given expression to a type which is accepted
6015/// by the given converter.
6016///
6017/// This routine will attempt to convert an expression of class type to a
6018/// type accepted by the specified converter. In C++11 and before, the class
6019/// must have a single non-explicit conversion function converting to a matching
6020/// type. In C++1y, there can be multiple such conversion functions, but only
6021/// one target type.
6022///
6023/// \param Loc The source location of the construct that requires the
6024/// conversion.
6025///
6026/// \param From The expression we're converting from.
6027///
6028/// \param Converter Used to control and diagnose the conversion process.
6029///
6030/// \returns The expression, converted to an integral or enumeration type if
6031/// successful.
6032ExprResult Sema::PerformContextualImplicitConversion(
  SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
// We can't perform any more checking for type-dependent expressions.
if (From->isTypeDependent())
  return From;

// Process placeholders immediately.
if (From->hasPlaceholderType()) {
  ExprResult result = CheckPlaceholderExpr(From);
  if (result.isInvalid())
    return result;
  From = result.get();
}

// If the expression already has a matching type, we're golden.
QualType T = From->getType();
if (Converter.match(T))
  return DefaultLvalueConversion(From);

// FIXME: Check for missing '()' if T is a function type?

// We can only perform contextual implicit conversions on objects of class
// type.
const RecordType *RecordTy = T->getAs<RecordType>();
if (!RecordTy || !getLangOpts().CPlusPlus) {
  if (!Converter.Suppress)
    Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
  return From;
}

// We must have a complete class type.
struct TypeDiagnoserPartialDiag : TypeDiagnoser {
  ContextualImplicitConverter &Converter;
  Expr *From;

  TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
      : Converter(Converter), From(From) {}

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
  }
} IncompleteDiagnoser(Converter, From);

if (Converter.Suppress ? !isCompleteType(Loc, T)
                       : RequireCompleteType(Loc, T, IncompleteDiagnoser))
  return From;

// Look for a conversion to an integral or enumeration type.
UnresolvedSet<4>
    ViableConversions; // These are *potentially* viable in C++1y.
UnresolvedSet<4> ExplicitConversions;
const auto &Conversions =
    cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();

bool HadMultipleCandidates =
    (std::distance(Conversions.begin(), Conversions.end()) > 1);

// To check that there is only one target type, in C++1y:
QualType ToType;
bool HasUniqueTargetType = true;

// Collect explicit or viable (potentially in C++1y) conversions.
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
  NamedDecl *D = (*I)->getUnderlyingDecl();
  CXXConversionDecl *Conversion;
  FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
  if (ConvTemplate) {
    if (getLangOpts().CPlusPlus14)
      Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
    else
      continue; // C++11 does not consider conversion operator templates(?).
  } else
    Conversion = cast<CXXConversionDecl>(D);

  assert((!ConvTemplate || getLangOpts().CPlusPlus14) &&((void)0)
         "Conversion operator templates are considered potentially "((void)0)
         "viable in C++1y")((void)0);

  QualType CurToType = Conversion->getConversionType().getNonReferenceType();
  if (Converter.match(CurToType) || ConvTemplate) {

    if (Conversion->isExplicit()) {
      // FIXME: For C++1y, do we need this restriction?
      // cf. diagnoseNoViableConversion()
      if (!ConvTemplate)
        ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
    } else {
      if (!ConvTemplate && getLangOpts().CPlusPlus14) {
        if (ToType.isNull())
          ToType = CurToType.getUnqualifiedType();
        else if (HasUniqueTargetType &&
                 (CurToType.getUnqualifiedType() != ToType))
          HasUniqueTargetType = false;
      }
      ViableConversions.addDecl(I.getDecl(), I.getAccess());
    }
  }
}

if (getLangOpts().CPlusPlus14) {
  // C++1y [conv]p6:
  // ... An expression e of class type E appearing in such a context
  // is said to be contextually implicitly converted to a specified
  // type T and is well-formed if and only if e can be implicitly
  // converted to a type T that is determined as follows: E is searched
  // for conversion functions whose return type is cv T or reference to
  // cv T such that T is allowed by the context. There shall be
  // exactly one such T.

  // If no unique T is found:
  if (ToType.isNull()) {
    if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
                                   HadMultipleCandidates,
                                   ExplicitConversions))
      return ExprError();
    return finishContextualImplicitConversion(*this, Loc, From, Converter);
  }

  // If more than one unique Ts are found:
  if (!HasUniqueTargetType)
    return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
                                       ViableConversions);

  // If one unique T is found:
  // First, build a candidate set from the previously recorded
  // potentially viable conversions.
  OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
  collectViableConversionCandidates(*this, From, ToType, ViableConversions,
                                    CandidateSet);

  // Then, perform overload resolution over the candidate set.
  OverloadCandidateSet::iterator Best;
  switch (CandidateSet.BestViableFunction(*this, Loc, Best)) {
  case OR_Success: {
    // Apply this conversion.
    DeclAccessPair Found =
        DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess());
    if (recordConversion(*this, Loc, From, Converter, T,
                         HadMultipleCandidates, Found))
      return ExprError();
    break;
  }
  case OR_Ambiguous:
    return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
                                       ViableConversions);
  case OR_No_Viable_Function:
    if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
                                   HadMultipleCandidates,
                                   ExplicitConversions))
      return ExprError();
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case OR_Deleted:
    // We'll complain below about a non-integral condition type.
    break;
  }
} else {
  switch (ViableConversions.size()) {
  case 0: {
    if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
                                   HadMultipleCandidates,
                                   ExplicitConversions))
      return ExprError();

    // We'll complain below about a non-integral condition type.
    break;
  }
  case 1: {
    // Apply this conversion.
    DeclAccessPair Found = ViableConversions[0];
    if (recordConversion(*this, Loc, From, Converter, T,
                         HadMultipleCandidates, Found))
      return ExprError();
    break;
  }
  default:
    return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
                                       ViableConversions);
  }
}

return finishContextualImplicitConversion(*this, Loc, From, Converter);
6213}

6215/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is
6216/// an acceptable non-member overloaded operator for a call whose
6217/// arguments have types T1 (and, if non-empty, T2). This routine
6218/// implements the check in C++ [over.match.oper]p3b2 concerning
6219/// enumeration types.
6220static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context,
                                                 FunctionDecl *Fn,
                                                 ArrayRef<Expr *> Args) {
QualType T1 = Args[0]->getType();
QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType();

if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType()))
  return true;

if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType()))
  return true;

const auto *Proto = Fn->getType()->castAs<FunctionProtoType>();
if (Proto->getNumParams() < 1)
  return false;

if (T1->isEnumeralType()) {
  QualType ArgType = Proto->getParamType(0).getNonReferenceType();
  if (Context.hasSameUnqualifiedType(T1, ArgType))
    return true;
}

if (Proto->getNumParams() < 2)
  return false;

if (!T2.isNull() && T2->isEnumeralType()) {
  QualType ArgType = Proto->getParamType(1).getNonReferenceType();
  if (Context.hasSameUnqualifiedType(T2, ArgType))
    return true;
}

return false;
6252}

6254/// AddOverloadCandidate - Adds the given function to the set of
6255/// candidate functions, using the given function call arguments.  If
6256/// @p SuppressUserConversions, then don't allow user-defined
6257/// conversions via constructors or conversion operators.
6258///
6259/// \param PartialOverloading true if we are performing "partial" overloading
6260/// based on an incomplete set of function arguments. This feature is used by
6261/// code completion.
6262void Sema::AddOverloadCandidate(
  FunctionDecl *Function, DeclAccessPair FoundDecl, ArrayRef<Expr *> Args,
  OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
  bool PartialOverloading, bool AllowExplicit, bool AllowExplicitConversions,
  ADLCallKind IsADLCandidate, ConversionSequenceList EarlyConversions,
  OverloadCandidateParamOrder PO) {
const FunctionProtoType *Proto
  = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>());
assert(Proto && "Functions without a prototype cannot be overloaded")((void)0);
assert(!Function->getDescribedFunctionTemplate() &&((void)0)
       "Use AddTemplateOverloadCandidate for function templates")((void)0);

if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
  if (!isa<CXXConstructorDecl>(Method)) {
    // If we get here, it's because we're calling a member function
    // that is named without a member access expression (e.g.,
    // "this->f") that was either written explicitly or created
    // implicitly. This can happen with a qualified call to a member
    // function, e.g., X::f(). We use an empty type for the implied
    // object argument (C++ [over.call.func]p3), and the acting context
    // is irrelevant.
    AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(),
                       Expr::Classification::makeSimpleLValue(), Args,
                       CandidateSet, SuppressUserConversions,
                       PartialOverloading, EarlyConversions, PO);
    return;
  }
  // We treat a constructor like a non-member function, since its object
  // argument doesn't participate in overload resolution.
}

if (!CandidateSet.isNewCandidate(Function, PO))
  return;

// C++11 [class.copy]p11: [DR1402]
//   A defaulted move constructor that is defined as deleted is ignored by
//   overload resolution.
CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function);
if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() &&
    Constructor->isMoveConstructor())
  return;

// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

// C++ [over.match.oper]p3:
//   if no operand has a class type, only those non-member functions in the
//   lookup set that have a first parameter of type T1 or "reference to
//   (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there
//   is a right operand) a second parameter of type T2 or "reference to
//   (possibly cv-qualified) T2", when T2 is an enumeration type, are
//   candidate functions.
if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator &&
    !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args))
  return;

// Add this candidate
OverloadCandidate &Candidate =
    CandidateSet.addCandidate(Args.size(), EarlyConversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Function;
Candidate.Viable = true;
Candidate.RewriteKind =
    CandidateSet.getRewriteInfo().getRewriteKind(Function, PO);
Candidate.IsSurrogate = false;
Candidate.IsADLCandidate = IsADLCandidate;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();

// Explicit functions are not actually candidates at all if we're not
// allowing them in this context, but keep them around so we can point
// to them in diagnostics.
if (!AllowExplicit && ExplicitSpecifier::getFromDecl(Function).isExplicit()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_explicit;
  return;
}

if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() &&
    !Function->getAttr<TargetAttr>()->isDefaultVersion()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_non_default_multiversion_function;
  return;
}

if (Constructor) {
  // C++ [class.copy]p3:
  //   A member function template is never instantiated to perform the copy
  //   of a class object to an object of its class type.
  QualType ClassType = Context.getTypeDeclType(Constructor->getParent());
  if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() &&
      (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) ||
       IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(),
                     ClassType))) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_illegal_constructor;
    return;
  }

  // C++ [over.match.funcs]p8: (proposed DR resolution)
  //   A constructor inherited from class type C that has a first parameter
  //   of type "reference to P" (including such a constructor instantiated
  //   from a template) is excluded from the set of candidate functions when
  //   constructing an object of type cv D if the argument list has exactly
  //   one argument and D is reference-related to P and P is reference-related
  //   to C.
  auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl());
  if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 &&
      Constructor->getParamDecl(0)->getType()->isReferenceType()) {
    QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType();
    QualType C = Context.getRecordType(Constructor->getParent());
    QualType D = Context.getRecordType(Shadow->getParent());
    SourceLocation Loc = Args.front()->getExprLoc();
    if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) &&
        (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_inhctor_slice;
      return;
    }
  }

  // Check that the constructor is capable of constructing an object in the
  // destination address space.
  if (!Qualifiers::isAddressSpaceSupersetOf(
          Constructor->getMethodQualifiers().getAddressSpace(),
          CandidateSet.getDestAS())) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_object_addrspace_mismatch;
  }
}

unsigned NumParams = Proto->getNumParams();

// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
    !Proto->isVariadic()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_many_arguments;
  return;
}

// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Function->getMinRequiredArguments();
if (Args.size() < MinRequiredArgs && !PartialOverloading) {
  // Not enough arguments.
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_few_arguments;
  return;
}

// (CUDA B.1): Check for invalid calls between targets.
if (getLangOpts().CUDA)
  if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
    // Skip the check for callers that are implicit members, because in this
    // case we may not yet know what the member's target is; the target is
    // inferred for the member automatically, based on the bases and fields of
    // the class.
    if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_bad_target;
      return;
    }

if (Function->getTrailingRequiresClause()) {
  ConstraintSatisfaction Satisfaction;
  if (CheckFunctionConstraints(Function, Satisfaction) ||
      !Satisfaction.IsSatisfied) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
    return;
  }
}

// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
  unsigned ConvIdx =
      PO == OverloadCandidateParamOrder::Reversed ? 1 - ArgIdx : ArgIdx;
  if (Candidate.Conversions[ConvIdx].isInitialized()) {
    // We already formed a conversion sequence for this parameter during
    // template argument deduction.
  } else if (ArgIdx < NumParams) {
    // (C++ 13.3.2p3): for F to be a viable function, there shall
    // exist for each argument an implicit conversion sequence
    // (13.3.3.1) that converts that argument to the corresponding
    // parameter of F.
    QualType ParamType = Proto->getParamType(ArgIdx);
    Candidate.Conversions[ConvIdx] = TryCopyInitialization(
        *this, Args[ArgIdx], ParamType, SuppressUserConversions,
        /*InOverloadResolution=*/true,
        /*AllowObjCWritebackConversion=*/
        getLangOpts().ObjCAutoRefCount, AllowExplicitConversions);
    if (Candidate.Conversions[ConvIdx].isBad()) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_bad_conversion;
      return;
    }
  } else {
    // (C++ 13.3.2p2): For the purposes of overload resolution, any
    // argument for which there is no corresponding parameter is
    // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
    Candidate.Conversions[ConvIdx].setEllipsis();
  }
}

if (EnableIfAttr *FailedAttr =
        CheckEnableIf(Function, CandidateSet.getLocation(), Args)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_enable_if;
  Candidate.DeductionFailure.Data = FailedAttr;
  return;
}
6481}

6483ObjCMethodDecl *
6484Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
                     SmallVectorImpl<ObjCMethodDecl *> &Methods) {
if (Methods.size() <= 1)
  return nullptr;

for (unsigned b = 0, e = Methods.size(); b < e; b++) {
  bool Match = true;
  ObjCMethodDecl *Method = Methods[b];
  unsigned NumNamedArgs = Sel.getNumArgs();
  // Method might have more arguments than selector indicates. This is due
  // to addition of c-style arguments in method.
  if (Method->param_size() > NumNamedArgs)
    NumNamedArgs = Method->param_size();
  if (Args.size() < NumNamedArgs)
    continue;

  for (unsigned i = 0; i < NumNamedArgs; i++) {
    // We can't do any type-checking on a type-dependent argument.
    if (Args[i]->isTypeDependent()) {
      Match = false;
      break;
    }

    ParmVarDecl *param = Method->parameters()[i];
    Expr *argExpr = Args[i];
    assert(argExpr && "SelectBestMethod(): missing expression")((void)0);

    // Strip the unbridged-cast placeholder expression off unless it's
    // a consumed argument.
    if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
        !param->hasAttr<CFConsumedAttr>())
      argExpr = stripARCUnbridgedCast(argExpr);

    // If the parameter is __unknown_anytype, move on to the next method.
    if (param->getType() == Context.UnknownAnyTy) {
      Match = false;
      break;
    }

    ImplicitConversionSequence ConversionState
      = TryCopyInitialization(*this, argExpr, param->getType(),
                              /*SuppressUserConversions*/false,
                              /*InOverloadResolution=*/true,
                              /*AllowObjCWritebackConversion=*/
                              getLangOpts().ObjCAutoRefCount,
                              /*AllowExplicit*/false);
    // This function looks for a reasonably-exact match, so we consider
    // incompatible pointer conversions to be a failure here.
    if (ConversionState.isBad() ||
        (ConversionState.isStandard() &&
         ConversionState.Standard.Second ==
             ICK_Incompatible_Pointer_Conversion)) {
      Match = false;
      break;
    }
  }
  // Promote additional arguments to variadic methods.
  if (Match && Method->isVariadic()) {
    for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
      if (Args[i]->isTypeDependent()) {
        Match = false;
        break;
      }
      ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
                                                        nullptr);
      if (Arg.isInvalid()) {
        Match = false;
        break;
      }
    }
  } else {
    // Check for extra arguments to non-variadic methods.
    if (Args.size() != NumNamedArgs)
      Match = false;
    else if (Match && NumNamedArgs == 0 && Methods.size() > 1) {
      // Special case when selectors have no argument. In this case, select
      // one with the most general result type of 'id'.
      for (unsigned b = 0, e = Methods.size(); b < e; b++) {
        QualType ReturnT = Methods[b]->getReturnType();
        if (ReturnT->isObjCIdType())
          return Methods[b];
      }
    }
  }

  if (Match)
    return Method;
}
return nullptr;
6573}

6575static bool convertArgsForAvailabilityChecks(
  Sema &S, FunctionDecl *Function, Expr *ThisArg, SourceLocation CallLoc,
  ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap, bool MissingImplicitThis,
  Expr *&ConvertedThis, SmallVectorImpl<Expr *> &ConvertedArgs) {
if (ThisArg) {
  CXXMethodDecl *Method = cast<CXXMethodDecl>(Function);
  assert(!isa<CXXConstructorDecl>(Method) &&((void)0)
         "Shouldn't have `this` for ctors!")((void)0);
  assert(!Method->isStatic() && "Shouldn't have `this` for static methods!")((void)0);
  ExprResult R = S.PerformObjectArgumentInitialization(
      ThisArg, /*Qualifier=*/nullptr, Method, Method);
  if (R.isInvalid())
    return false;
  ConvertedThis = R.get();
} else {
  if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) {
    (void)MD;
    assert((MissingImplicitThis || MD->isStatic() ||((void)0)
            isa<CXXConstructorDecl>(MD)) &&((void)0)
           "Expected `this` for non-ctor instance methods")((void)0);
  }
  ConvertedThis = nullptr;
}

// Ignore any variadic arguments. Converting them is pointless, since the
// user can't refer to them in the function condition.
unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size());

// Convert the arguments.
for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) {
  ExprResult R;
  R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
                                      S.Context, Function->getParamDecl(I)),
                                  SourceLocation(), Args[I]);

  if (R.isInvalid())
    return false;

  ConvertedArgs.push_back(R.get());
}

if (Trap.hasErrorOccurred())
  return false;

// Push default arguments if needed.
if (!Function->isVariadic() && Args.size() < Function->getNumParams()) {
  for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) {
    ParmVarDecl *P = Function->getParamDecl(i);
    if (!P->hasDefaultArg())
      return false;
    ExprResult R = S.BuildCXXDefaultArgExpr(CallLoc, Function, P);
    if (R.isInvalid())
      return false;
    ConvertedArgs.push_back(R.get());
  }

  if (Trap.hasErrorOccurred())
    return false;
}
return true;
6635}

6637EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function,
                                SourceLocation CallLoc,
                                ArrayRef<Expr *> Args,
                                bool MissingImplicitThis) {
auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>();
if (EnableIfAttrs.begin() == EnableIfAttrs.end())
  return nullptr;

SFINAETrap Trap(*this);
SmallVector<Expr *, 16> ConvertedArgs;
// FIXME: We should look into making enable_if late-parsed.
Expr *DiscardedThis;
if (!convertArgsForAvailabilityChecks(
        *this, Function, /*ThisArg=*/nullptr, CallLoc, Args, Trap,
        /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs))
  return *EnableIfAttrs.begin();

for (auto *EIA : EnableIfAttrs) {
  APValue Result;
  // FIXME: This doesn't consider value-dependent cases, because doing so is
  // very difficult. Ideally, we should handle them more gracefully.
  if (EIA->getCond()->isValueDependent() ||
      !EIA->getCond()->EvaluateWithSubstitution(
          Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
    return EIA;

  if (!Result.isInt() || !Result.getInt().getBoolValue())
    return EIA;
}
return nullptr;
6667}

6669template <typename CheckFn>
6670static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND,
                                      bool ArgDependent, SourceLocation Loc,
                                      CheckFn &&IsSuccessful) {
SmallVector<const DiagnoseIfAttr *, 8> Attrs;
for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) {
  if (ArgDependent == DIA->getArgDependent())
    Attrs.push_back(DIA);
}

// Common case: No diagnose_if attributes, so we can quit early.
if (Attrs.empty())
  return false;

auto WarningBegin = std::stable_partition(
    Attrs.begin(), Attrs.end(),
    [](const DiagnoseIfAttr *DIA) { return DIA->isError(); });

// Note that diagnose_if attributes are late-parsed, so they appear in the
// correct order (unlike enable_if attributes).
auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin),
                             IsSuccessful);
if (ErrAttr != WarningBegin) {
  const DiagnoseIfAttr *DIA = *ErrAttr;
  S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage();
  S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
      << DIA->getParent() << DIA->getCond()->getSourceRange();
  return true;
}

for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end()))
  if (IsSuccessful(DIA)) {
    S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage();
    S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
        << DIA->getParent() << DIA->getCond()->getSourceRange();
  }

return false;
6707}

6709bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
                                             const Expr *ThisArg,
                                             ArrayRef<const Expr *> Args,
                                             SourceLocation Loc) {
return diagnoseDiagnoseIfAttrsWith(
    *this, Function, /*ArgDependent=*/true, Loc,
    [&](const DiagnoseIfAttr *DIA) {
      APValue Result;
      // It's sane to use the same Args for any redecl of this function, since
      // EvaluateWithSubstitution only cares about the position of each
      // argument in the arg list, not the ParmVarDecl* it maps to.
      if (!DIA->getCond()->EvaluateWithSubstitution(
              Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
        return false;
      return Result.isInt() && Result.getInt().getBoolValue();
    });
6725}

6727bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
                                               SourceLocation Loc) {
return diagnoseDiagnoseIfAttrsWith(
    *this, ND, /*ArgDependent=*/false, Loc,
    [&](const DiagnoseIfAttr *DIA) {
      bool Result;
      return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) &&
             Result;
    });
6736}

6738/// Add all of the function declarations in the given function set to
6739/// the overload candidate set.
6740void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
                               ArrayRef<Expr *> Args,
                               OverloadCandidateSet &CandidateSet,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                               bool SuppressUserConversions,
                               bool PartialOverloading,
                               bool FirstArgumentIsBase) {
for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
  NamedDecl *D = F.getDecl()->getUnderlyingDecl();
  ArrayRef<Expr *> FunctionArgs = Args;

  FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
  FunctionDecl *FD =
      FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);

  if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
    QualType ObjectType;
    Expr::Classification ObjectClassification;
    if (Args.size() > 0) {
      if (Expr *E = Args[0]) {
        // Use the explicit base to restrict the lookup:
        ObjectType = E->getType();
        // Pointers in the object arguments are implicitly dereferenced, so we
        // always classify them as l-values.
        if (!ObjectType.isNull() && ObjectType->isPointerType())
          ObjectClassification = Expr::Classification::makeSimpleLValue();
        else
          ObjectClassification = E->Classify(Context);
      } // .. else there is an implicit base.
      FunctionArgs = Args.slice(1);
    }
    if (FunTmpl) {
      AddMethodTemplateCandidate(
          FunTmpl, F.getPair(),
          cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
          ExplicitTemplateArgs, ObjectType, ObjectClassification,
          FunctionArgs, CandidateSet, SuppressUserConversions,
          PartialOverloading);
    } else {
      AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
                         cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
                         ObjectClassification, FunctionArgs, CandidateSet,
                         SuppressUserConversions, PartialOverloading);
    }
  } else {
    // This branch handles both standalone functions and static methods.

    // Slice the first argument (which is the base) when we access
    // static method as non-static.
    if (Args.size() > 0 &&
        (!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) &&
                      !isa<CXXConstructorDecl>(FD)))) {
      assert(cast<CXXMethodDecl>(FD)->isStatic())((void)0);
      FunctionArgs = Args.slice(1);
    }
    if (FunTmpl) {
      AddTemplateOverloadCandidate(FunTmpl, F.getPair(),
                                   ExplicitTemplateArgs, FunctionArgs,
                                   CandidateSet, SuppressUserConversions,
                                   PartialOverloading);
    } else {
      AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet,
                           SuppressUserConversions, PartialOverloading);
    }
  }
}
6806}

6808/// AddMethodCandidate - Adds a named decl (which is some kind of
6809/// method) as a method candidate to the given overload set.
6810void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
                            Expr::Classification ObjectClassification,
                            ArrayRef<Expr *> Args,
                            OverloadCandidateSet &CandidateSet,
                            bool SuppressUserConversions,
                            OverloadCandidateParamOrder PO) {
NamedDecl *Decl = FoundDecl.getDecl();
CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext());

if (isa<UsingShadowDecl>(Decl))
  Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl();

if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) {
  assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) &&((void)0)
         "Expected a member function template")((void)0);
  AddMethodTemplateCandidate(TD, FoundDecl, ActingContext,
                             /*ExplicitArgs*/ nullptr, ObjectType,
                             ObjectClassification, Args, CandidateSet,
                             SuppressUserConversions, false, PO);
} else {
  AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext,
                     ObjectType, ObjectClassification, Args, CandidateSet,
                     SuppressUserConversions, false, None, PO);
}
6834}

6836/// AddMethodCandidate - Adds the given C++ member function to the set
6837/// of candidate functions, using the given function call arguments
6838/// and the object argument (@c Object). For example, in a call
6839/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
6840/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
6841/// allow user-defined conversions via constructors or conversion
6842/// operators.
6843void
6844Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
                       CXXRecordDecl *ActingContext, QualType ObjectType,
                       Expr::Classification ObjectClassification,
                       ArrayRef<Expr *> Args,
                       OverloadCandidateSet &CandidateSet,
                       bool SuppressUserConversions,
                       bool PartialOverloading,
                       ConversionSequenceList EarlyConversions,
                       OverloadCandidateParamOrder PO) {
const FunctionProtoType *Proto
  = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>());
assert(Proto && "Methods without a prototype cannot be overloaded")((void)0);
assert(!isa<CXXConstructorDecl>(Method) &&((void)0)
       "Use AddOverloadCandidate for constructors")((void)0);

if (!CandidateSet.isNewCandidate(Method, PO))
  return;

// C++11 [class.copy]p23: [DR1402]
//   A defaulted move assignment operator that is defined as deleted is
//   ignored by overload resolution.
if (Method->isDefaulted() && Method->isDeleted() &&
    Method->isMoveAssignmentOperator())
  return;

// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

// Add this candidate
OverloadCandidate &Candidate =
    CandidateSet.addCandidate(Args.size() + 1, EarlyConversions);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Method;
Candidate.RewriteKind =
    CandidateSet.getRewriteInfo().getRewriteKind(Method, PO);
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();

unsigned NumParams = Proto->getNumParams();

// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
    !Proto->isVariadic()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_many_arguments;
  return;
}

// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Method->getMinRequiredArguments();
if (Args.size() < MinRequiredArgs && !PartialOverloading) {
  // Not enough arguments.
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_few_arguments;
  return;
}

Candidate.Viable = true;

if (Method->isStatic() || ObjectType.isNull())
  // The implicit object argument is ignored.
  Candidate.IgnoreObjectArgument = true;
else {
  unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
  // Determine the implicit conversion sequence for the object
  // parameter.
  Candidate.Conversions[ConvIdx] = TryObjectArgumentInitialization(
      *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
      Method, ActingContext);
  if (Candidate.Conversions[ConvIdx].isBad()) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_bad_conversion;
    return;
  }
}

// (CUDA B.1): Check for invalid calls between targets.
if (getLangOpts().CUDA)
  if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
    if (!IsAllowedCUDACall(Caller, Method)) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_bad_target;
      return;
    }

if (Method->getTrailingRequiresClause()) {
  ConstraintSatisfaction Satisfaction;
  if (CheckFunctionConstraints(Method, Satisfaction) ||
      !Satisfaction.IsSatisfied) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
    return;
  }
}

// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
  unsigned ConvIdx =
      PO == OverloadCandidateParamOrder::Reversed ? 0 : (ArgIdx + 1);
  if (Candidate.Conversions[ConvIdx].isInitialized()) {
    // We already formed a conversion sequence for this parameter during
    // template argument deduction.
  } else if (ArgIdx < NumParams) {
    // (C++ 13.3.2p3): for F to be a viable function, there shall
    // exist for each argument an implicit conversion sequence
    // (13.3.3.1) that converts that argument to the corresponding
    // parameter of F.
    QualType ParamType = Proto->getParamType(ArgIdx);
    Candidate.Conversions[ConvIdx]
      = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
                              SuppressUserConversions,
                              /*InOverloadResolution=*/true,
                              /*AllowObjCWritebackConversion=*/
                                getLangOpts().ObjCAutoRefCount);
    if (Candidate.Conversions[ConvIdx].isBad()) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_bad_conversion;
      return;
    }
  } else {
    // (C++ 13.3.2p2): For the purposes of overload resolution, any
    // argument for which there is no corresponding parameter is
    // considered to "match the ellipsis" (C+ 13.3.3.1.3).
    Candidate.Conversions[ConvIdx].setEllipsis();
  }
}

if (EnableIfAttr *FailedAttr =
        CheckEnableIf(Method, CandidateSet.getLocation(), Args, true)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_enable_if;
  Candidate.DeductionFailure.Data = FailedAttr;
  return;
}

if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() &&
    !Method->getAttr<TargetAttr>()->isDefaultVersion()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_non_default_multiversion_function;
}
6993}

6995/// Add a C++ member function template as a candidate to the candidate
6996/// set, using template argument deduction to produce an appropriate member
6997/// function template specialization.
6998void Sema::AddMethodTemplateCandidate(
  FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
  CXXRecordDecl *ActingContext,
  TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
  Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
  OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
  bool PartialOverloading, OverloadCandidateParamOrder PO) {
if (!CandidateSet.isNewCandidate(MethodTmpl, PO))
  return;

// C++ [over.match.funcs]p7:
//   In each case where a candidate is a function template, candidate
//   function template specializations are generated using template argument
//   deduction (14.8.3, 14.8.2). Those candidates are then handled as
//   candidate functions in the usual way.113) A given name can refer to one
//   or more function templates and also to a set of overloaded non-template
//   functions. In such a case, the candidate functions generated from each
//   function template are combined with the set of non-template candidate
//   functions.
TemplateDeductionInfo Info(CandidateSet.getLocation());
FunctionDecl *Specialization = nullptr;
ConversionSequenceList Conversions;
if (TemplateDeductionResult Result = DeduceTemplateArguments(
        MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info,
        PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
          return CheckNonDependentConversions(
              MethodTmpl, ParamTypes, Args, CandidateSet, Conversions,
              SuppressUserConversions, ActingContext, ObjectType,
              ObjectClassification, PO);
        })) {
  OverloadCandidate &Candidate =
      CandidateSet.addCandidate(Conversions.size(), Conversions);
  Candidate.FoundDecl = FoundDecl;
  Candidate.Function = MethodTmpl->getTemplatedDecl();
  Candidate.Viable = false;
  Candidate.RewriteKind =
    CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
  Candidate.IsSurrogate = false;
  Candidate.IgnoreObjectArgument =
      cast<CXXMethodDecl>(Candidate.Function)->isStatic() ||
      ObjectType.isNull();
  Candidate.ExplicitCallArguments = Args.size();
  if (Result == TDK_NonDependentConversionFailure)
    Candidate.FailureKind = ovl_fail_bad_conversion;
  else {
    Candidate.FailureKind = ovl_fail_bad_deduction;
    Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
                                                          Info);
  }
  return;
}

// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing member function template specialization?")((void)0);
assert(isa<CXXMethodDecl>(Specialization) &&((void)0)
       "Specialization is not a member function?")((void)0);
AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl,
                   ActingContext, ObjectType, ObjectClassification, Args,
                   CandidateSet, SuppressUserConversions, PartialOverloading,
                   Conversions, PO);
7059}

7061/// Determine whether a given function template has a simple explicit specifier
7062/// or a non-value-dependent explicit-specification that evaluates to true.
7063static bool isNonDependentlyExplicit(FunctionTemplateDecl *FTD) {
return ExplicitSpecifier::getFromDecl(FTD->getTemplatedDecl()).isExplicit();
7065}

7067/// Add a C++ function template specialization as a candidate
7068/// in the candidate set, using template argument deduction to produce
7069/// an appropriate function template specialization.
7070void Sema::AddTemplateOverloadCandidate(
  FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
  TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
  OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
  bool PartialOverloading, bool AllowExplicit, ADLCallKind IsADLCandidate,
  OverloadCandidateParamOrder PO) {
if (!CandidateSet.isNewCandidate(FunctionTemplate, PO))
  return;

// If the function template has a non-dependent explicit specification,
// exclude it now if appropriate; we are not permitted to perform deduction
// and substitution in this case.
if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
  OverloadCandidate &Candidate = CandidateSet.addCandidate();
  Candidate.FoundDecl = FoundDecl;
  Candidate.Function = FunctionTemplate->getTemplatedDecl();
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_explicit;
  return;
}

// C++ [over.match.funcs]p7:
//   In each case where a candidate is a function template, candidate
//   function template specializations are generated using template argument
//   deduction (14.8.3, 14.8.2). Those candidates are then handled as
//   candidate functions in the usual way.113) A given name can refer to one
//   or more function templates and also to a set of overloaded non-template
//   functions. In such a case, the candidate functions generated from each
//   function template are combined with the set of non-template candidate
//   functions.
TemplateDeductionInfo Info(CandidateSet.getLocation());
FunctionDecl *Specialization = nullptr;
ConversionSequenceList Conversions;
if (TemplateDeductionResult Result = DeduceTemplateArguments(
        FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info,
        PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
          return CheckNonDependentConversions(
              FunctionTemplate, ParamTypes, Args, CandidateSet, Conversions,
              SuppressUserConversions, nullptr, QualType(), {}, PO);
        })) {
  OverloadCandidate &Candidate =
      CandidateSet.addCandidate(Conversions.size(), Conversions);
  Candidate.FoundDecl = FoundDecl;
  Candidate.Function = FunctionTemplate->getTemplatedDecl();
  Candidate.Viable = false;
  Candidate.RewriteKind =
    CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
  Candidate.IsSurrogate = false;
  Candidate.IsADLCandidate = IsADLCandidate;
  // Ignore the object argument if there is one, since we don't have an object
  // type.
  Candidate.IgnoreObjectArgument =
      isa<CXXMethodDecl>(Candidate.Function) &&
      !isa<CXXConstructorDecl>(Candidate.Function);
  Candidate.ExplicitCallArguments = Args.size();
  if (Result == TDK_NonDependentConversionFailure)
    Candidate.FailureKind = ovl_fail_bad_conversion;
  else {
    Candidate.FailureKind = ovl_fail_bad_deduction;
    Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
                                                          Info);
  }
  return;
}

// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing function template specialization?")((void)0);
AddOverloadCandidate(
    Specialization, FoundDecl, Args, CandidateSet, SuppressUserConversions,
    PartialOverloading, AllowExplicit,
    /*AllowExplicitConversions*/ false, IsADLCandidate, Conversions, PO);
7142}

7144/// Check that implicit conversion sequences can be formed for each argument
7145/// whose corresponding parameter has a non-dependent type, per DR1391's
7146/// [temp.deduct.call]p10.
7147bool Sema::CheckNonDependentConversions(
  FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
  ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
  ConversionSequenceList &Conversions, bool SuppressUserConversions,
  CXXRecordDecl *ActingContext, QualType ObjectType,
  Expr::Classification ObjectClassification, OverloadCandidateParamOrder PO) {
// FIXME: The cases in which we allow explicit conversions for constructor
// arguments never consider calling a constructor template. It's not clear
// that is correct.
const bool AllowExplicit = false;

auto *FD = FunctionTemplate->getTemplatedDecl();
auto *Method = dyn_cast<CXXMethodDecl>(FD);
bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method);
unsigned ThisConversions = HasThisConversion ? 1 : 0;

Conversions =
    CandidateSet.allocateConversionSequences(ThisConversions + Args.size());

// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

// For a method call, check the 'this' conversion here too. DR1391 doesn't
// require that, but this check should never result in a hard error, and
// overload resolution is permitted to sidestep instantiations.
if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() &&
    !ObjectType.isNull()) {
  unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
  Conversions[ConvIdx] = TryObjectArgumentInitialization(
      *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
      Method, ActingContext);
  if (Conversions[ConvIdx].isBad())
    return true;
}

for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
     ++I) {
  QualType ParamType = ParamTypes[I];
  if (!ParamType->isDependentType()) {
    unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed
                           ? 0
                           : (ThisConversions + I);
    Conversions[ConvIdx]
      = TryCopyInitialization(*this, Args[I], ParamType,
                              SuppressUserConversions,
                              /*InOverloadResolution=*/true,
                              /*AllowObjCWritebackConversion=*/
                                getLangOpts().ObjCAutoRefCount,
                              AllowExplicit);
    if (Conversions[ConvIdx].isBad())
      return true;
  }
}

return false;
7203}

7205/// Determine whether this is an allowable conversion from the result
7206/// of an explicit conversion operator to the expected type, per C++
7207/// [over.match.conv]p1 and [over.match.ref]p1.
7208///
7209/// \param ConvType The return type of the conversion function.
7210///
7211/// \param ToType The type we are converting to.
7212///
7213/// \param AllowObjCPointerConversion Allow a conversion from one
7214/// Objective-C pointer to another.
7215///
7216/// \returns true if the conversion is allowable, false otherwise.
7217static bool isAllowableExplicitConversion(Sema &S,
                                        QualType ConvType, QualType ToType,
                                        bool AllowObjCPointerConversion) {
QualType ToNonRefType = ToType.getNonReferenceType();

// Easy case: the types are the same.
if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType))
  return true;

// Allow qualification conversions.
bool ObjCLifetimeConversion;
if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false,
                                ObjCLifetimeConversion))
  return true;

// If we're not allowed to consider Objective-C pointer conversions,
// we're done.
if (!AllowObjCPointerConversion)
  return false;

// Is this an Objective-C pointer conversion?
bool IncompatibleObjC = false;
QualType ConvertedType;
return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType,
                                 IncompatibleObjC);
7242}

7244/// AddConversionCandidate - Add a C++ conversion function as a
7245/// candidate in the candidate set (C++ [over.match.conv],
7246/// C++ [over.match.copy]). From is the expression we're converting from,
7247/// and ToType is the type that we're eventually trying to convert to
7248/// (which may or may not be the same type as the type that the
7249/// conversion function produces).
7250void Sema::AddConversionCandidate(
  CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
  CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
  OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
  bool AllowExplicit, bool AllowResultConversion) {
assert(!Conversion->getDescribedFunctionTemplate() &&((void)0)
       "Conversion function templates use AddTemplateConversionCandidate")((void)0);
QualType ConvType = Conversion->getConversionType().getNonReferenceType();
if (!CandidateSet.isNewCandidate(Conversion))
  return;

// If the conversion function has an undeduced return type, trigger its
// deduction now.
if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) {
  if (DeduceReturnType(Conversion, From->getExprLoc()))
    return;
  ConvType = Conversion->getConversionType().getNonReferenceType();
}

// If we don't allow any conversion of the result type, ignore conversion
// functions that don't convert to exactly (possibly cv-qualified) T.
if (!AllowResultConversion &&
    !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType))
  return;

// Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion
// operator is only a candidate if its return type is the target type or
// can be converted to the target type with a qualification conversion.
//
// FIXME: Include such functions in the candidate list and explain why we
// can't select them.
if (Conversion->isExplicit() &&
    !isAllowableExplicitConversion(*this, ConvType, ToType,
                                   AllowObjCConversionOnExplicit))
  return;

// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

// Add this candidate
OverloadCandidate &Candidate = CandidateSet.addCandidate(1);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = Conversion;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.FinalConversion.setAsIdentityConversion();
Candidate.FinalConversion.setFromType(ConvType);
Candidate.FinalConversion.setAllToTypes(ToType);
Candidate.Viable = true;
Candidate.ExplicitCallArguments = 1;

// Explicit functions are not actually candidates at all if we're not
// allowing them in this context, but keep them around so we can point
// to them in diagnostics.
if (!AllowExplicit && Conversion->isExplicit()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_explicit;
  return;
}

// C++ [over.match.funcs]p4:
//   For conversion functions, the function is considered to be a member of
//   the class of the implicit implied object argument for the purpose of
//   defining the type of the implicit object parameter.
//
// Determine the implicit conversion sequence for the implicit
// object parameter.
QualType ImplicitParamType = From->getType();
if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>())
  ImplicitParamType = FromPtrType->getPointeeType();
CXXRecordDecl *ConversionContext
  = cast<CXXRecordDecl>(ImplicitParamType->castAs<RecordType>()->getDecl());

Candidate.Conversions[0] = TryObjectArgumentInitialization(
    *this, CandidateSet.getLocation(), From->getType(),
    From->Classify(Context), Conversion, ConversionContext);

if (Candidate.Conversions[0].isBad()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_bad_conversion;
  return;
}

if (Conversion->getTrailingRequiresClause()) {
  ConstraintSatisfaction Satisfaction;
  if (CheckFunctionConstraints(Conversion, Satisfaction) ||
      !Satisfaction.IsSatisfied) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
    return;
  }
}

// We won't go through a user-defined type conversion function to convert a
// derived to base as such conversions are given Conversion Rank. They only
// go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user]
QualType FromCanon
  = Context.getCanonicalType(From->getType().getUnqualifiedType());
QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
if (FromCanon == ToCanon ||
    IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_trivial_conversion;
  return;
}

// To determine what the conversion from the result of calling the
// conversion function to the type we're eventually trying to
// convert to (ToType), we need to synthesize a call to the
// conversion function and attempt copy initialization from it. This
// makes sure that we get the right semantics with respect to
// lvalues/rvalues and the type. Fortunately, we can allocate this
// call on the stack and we don't need its arguments to be
// well-formed.
DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(),
                          VK_LValue, From->getBeginLoc());
ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack,
                              Context.getPointerType(Conversion->getType()),
                              CK_FunctionToPointerDecay, &ConversionRef,
                              VK_PRValue, FPOptionsOverride());

QualType ConversionType = Conversion->getConversionType();
if (!isCompleteType(From->getBeginLoc(), ConversionType)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_bad_final_conversion;
  return;
}

ExprValueKind VK = Expr::getValueKindForType(ConversionType);

// Note that it is safe to allocate CallExpr on the stack here because
// there are 0 arguments (i.e., nothing is allocated using ASTContext's
// allocator).
QualType CallResultType = ConversionType.getNonLValueExprType(Context);

alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
    Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());

ImplicitConversionSequence ICS =
    TryCopyInitialization(*this, TheTemporaryCall, ToType,
                          /*SuppressUserConversions=*/true,
                          /*InOverloadResolution=*/false,
                          /*AllowObjCWritebackConversion=*/false);

switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
  Candidate.FinalConversion = ICS.Standard;

  // C++ [over.ics.user]p3:
  //   If the user-defined conversion is specified by a specialization of a
  //   conversion function template, the second standard conversion sequence
  //   shall have exact match rank.
  if (Conversion->getPrimaryTemplate() &&
      GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
    return;
  }

  // C++0x [dcl.init.ref]p5:
  //    In the second case, if the reference is an rvalue reference and
  //    the second standard conversion sequence of the user-defined
  //    conversion sequence includes an lvalue-to-rvalue conversion, the
  //    program is ill-formed.
  if (ToType->isRValueReferenceType() &&
      ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_bad_final_conversion;
    return;
  }
  break;

case ImplicitConversionSequence::BadConversion:
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_bad_final_conversion;
  return;

default:
  llvm_unreachable(__builtin_unreachable()
         "Can only end up with a standard conversion sequence or failure")__builtin_unreachable();
}

if (EnableIfAttr *FailedAttr =
        CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_enable_if;
  Candidate.DeductionFailure.Data = FailedAttr;
  return;
}

if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() &&
    !Conversion->getAttr<TargetAttr>()->isDefaultVersion()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_non_default_multiversion_function;
}
7447}

7449/// Adds a conversion function template specialization
7450/// candidate to the overload set, using template argument deduction
7451/// to deduce the template arguments of the conversion function
7452/// template from the type that we are converting to (C++
7453/// [temp.deduct.conv]).
7454void Sema::AddTemplateConversionCandidate(
  FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
  CXXRecordDecl *ActingDC, Expr *From, QualType ToType,
  OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
  bool AllowExplicit, bool AllowResultConversion) {
assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&((void)0)
       "Only conversion function templates permitted here")((void)0);

if (!CandidateSet.isNewCandidate(FunctionTemplate))
  return;

// If the function template has a non-dependent explicit specification,
// exclude it now if appropriate; we are not permitted to perform deduction
// and substitution in this case.
if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
  OverloadCandidate &Candidate = CandidateSet.addCandidate();
  Candidate.FoundDecl = FoundDecl;
  Candidate.Function = FunctionTemplate->getTemplatedDecl();
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_explicit;
  return;
}

TemplateDeductionInfo Info(CandidateSet.getLocation());
CXXConversionDecl *Specialization = nullptr;
if (TemplateDeductionResult Result
      = DeduceTemplateArguments(FunctionTemplate, ToType,
                                Specialization, Info)) {
  OverloadCandidate &Candidate = CandidateSet.addCandidate();
  Candidate.FoundDecl = FoundDecl;
  Candidate.Function = FunctionTemplate->getTemplatedDecl();
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_bad_deduction;
  Candidate.IsSurrogate = false;
  Candidate.IgnoreObjectArgument = false;
  Candidate.ExplicitCallArguments = 1;
  Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
                                                        Info);
  return;
}

// Add the conversion function template specialization produced by
// template argument deduction as a candidate.
assert(Specialization && "Missing function template specialization?")((void)0);
AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType,
                       CandidateSet, AllowObjCConversionOnExplicit,
                       AllowExplicit, AllowResultConversion);
7501}

7503/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
7504/// converts the given @c Object to a function pointer via the
7505/// conversion function @c Conversion, and then attempts to call it
7506/// with the given arguments (C++ [over.call.object]p2-4). Proto is
7507/// the type of function that we'll eventually be calling.
7508void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
                               DeclAccessPair FoundDecl,
                               CXXRecordDecl *ActingContext,
                               const FunctionProtoType *Proto,
                               Expr *Object,
                               ArrayRef<Expr *> Args,
                               OverloadCandidateSet& CandidateSet) {
if (!CandidateSet.isNewCandidate(Conversion))
  return;

// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1);
Candidate.FoundDecl = FoundDecl;
Candidate.Function = nullptr;
Candidate.Surrogate = Conversion;
Candidate.Viable = true;
Candidate.IsSurrogate = true;
Candidate.IgnoreObjectArgument = false;
Candidate.ExplicitCallArguments = Args.size();

// Determine the implicit conversion sequence for the implicit
// object parameter.
ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization(
    *this, CandidateSet.getLocation(), Object->getType(),
    Object->Classify(Context), Conversion, ActingContext);
if (ObjectInit.isBad()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_bad_conversion;
  Candidate.Conversions[0] = ObjectInit;
  return;
}

// The first conversion is actually a user-defined conversion whose
// first conversion is ObjectInit's standard conversion (which is
// effectively a reference binding). Record it as such.
Candidate.Conversions[0].setUserDefined();
Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
Candidate.Conversions[0].UserDefined.EllipsisConversion = false;
Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false;
Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl;
Candidate.Conversions[0].UserDefined.After
  = Candidate.Conversions[0].UserDefined.Before;
Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();

// Find the
unsigned NumParams = Proto->getNumParams();

// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (Args.size() > NumParams && !Proto->isVariadic()) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_many_arguments;
  return;
}

// Function types don't have any default arguments, so just check if
// we have enough arguments.
if (Args.size() < NumParams) {
  // Not enough arguments.
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_too_few_arguments;
  return;
}

// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
  if (ArgIdx < NumParams) {
    // (C++ 13.3.2p3): for F to be a viable function, there shall
    // exist for each argument an implicit conversion sequence
    // (13.3.3.1) that converts that argument to the corresponding
    // parameter of F.
    QualType ParamType = Proto->getParamType(ArgIdx);
    Candidate.Conversions[ArgIdx + 1]
      = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
                              /*SuppressUserConversions=*/false,
                              /*InOverloadResolution=*/false,
                              /*AllowObjCWritebackConversion=*/
                                getLangOpts().ObjCAutoRefCount);
    if (Candidate.Conversions[ArgIdx + 1].isBad()) {
      Candidate.Viable = false;
      Candidate.FailureKind = ovl_fail_bad_conversion;
      return;
    }
  } else {
    // (C++ 13.3.2p2): For the purposes of overload resolution, any
    // argument for which there is no corresponding parameter is
    // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
    Candidate.Conversions[ArgIdx + 1].setEllipsis();
  }
}

if (EnableIfAttr *FailedAttr =
        CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
  Candidate.Viable = false;
  Candidate.FailureKind = ovl_fail_enable_if;
  Candidate.DeductionFailure.Data = FailedAttr;
  return;
}
7612}

7614/// Add all of the non-member operator function declarations in the given
7615/// function set to the overload candidate set.
7616void Sema::AddNonMemberOperatorCandidates(
  const UnresolvedSetImpl &Fns, ArrayRef<Expr *> Args,
  OverloadCandidateSet &CandidateSet,
  TemplateArgumentListInfo *ExplicitTemplateArgs) {
for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
  NamedDecl *D = F.getDecl()->getUnderlyingDecl();
  ArrayRef<Expr *> FunctionArgs = Args;

  FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
  FunctionDecl *FD =
      FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);

  // Don't consider rewritten functions if we're not rewriting.
  if (!CandidateSet.getRewriteInfo().isAcceptableCandidate(FD))
    continue;

  assert(!isa<CXXMethodDecl>(FD) &&((void)0)
         "unqualified operator lookup found a member function")((void)0);

  if (FunTmpl) {
    AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs,
                                 FunctionArgs, CandidateSet);
    if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
      AddTemplateOverloadCandidate(
          FunTmpl, F.getPair(), ExplicitTemplateArgs,
          {FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false,
          true, ADLCallKind::NotADL, OverloadCandidateParamOrder::Reversed);
  } else {
    if (ExplicitTemplateArgs)
      continue;
    AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet);
    if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
      AddOverloadCandidate(FD, F.getPair(),
                           {FunctionArgs[1], FunctionArgs[0]}, CandidateSet,
                           false, false, true, false, ADLCallKind::NotADL,
                           None, OverloadCandidateParamOrder::Reversed);
  }
}
7654}

7656/// Add overload candidates for overloaded operators that are
7657/// member functions.
7658///
7659/// Add the overloaded operator candidates that are member functions
7660/// for the operator Op that was used in an operator expression such
7661/// as "x Op y". , Args/NumArgs provides the operator arguments, and
7662/// CandidateSet will store the added overload candidates. (C++
7663/// [over.match.oper]).
7664void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
                                     SourceLocation OpLoc,
                                     ArrayRef<Expr *> Args,
                                     OverloadCandidateSet &CandidateSet,
                                     OverloadCandidateParamOrder PO) {
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);

// C++ [over.match.oper]p3:
//   For a unary operator @ with an operand of a type whose
//   cv-unqualified version is T1, and for a binary operator @ with
//   a left operand of a type whose cv-unqualified version is T1 and
//   a right operand of a type whose cv-unqualified version is T2,
//   three sets of candidate functions, designated member
//   candidates, non-member candidates and built-in candidates, are
//   constructed as follows:
QualType T1 = Args[0]->getType();

//     -- If T1 is a complete class type or a class currently being
//        defined, the set of member candidates is the result of the
//        qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
//        the set of member candidates is empty.
if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
  // Complete the type if it can be completed.
  if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined())
    return;
  // If the type is neither complete nor being defined, bail out now.
  if (!T1Rec->getDecl()->getDefinition())
    return;

  LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName);
  LookupQualifiedName(Operators, T1Rec->getDecl());
  Operators.suppressDiagnostics();

  for (LookupResult::iterator Oper = Operators.begin(),
                           OperEnd = Operators.end();
       Oper != OperEnd;
       ++Oper)
    AddMethodCandidate(Oper.getPair(), Args[0]->getType(),
                       Args[0]->Classify(Context), Args.slice(1),
                       CandidateSet, /*SuppressUserConversion=*/false, PO);
}
7705}

7707/// AddBuiltinCandidate - Add a candidate for a built-in
7708/// operator. ResultTy and ParamTys are the result and parameter types
7709/// of the built-in candidate, respectively. Args and NumArgs are the
7710/// arguments being passed to the candidate. IsAssignmentOperator
7711/// should be true when this built-in candidate is an assignment
7712/// operator. NumContextualBoolArguments is the number of arguments
7713/// (at the beginning of the argument list) that will be contextually
7714/// converted to bool.
7715void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
                             OverloadCandidateSet& CandidateSet,
                             bool IsAssignmentOperator,
                             unsigned NumContextualBoolArguments) {
// Overload resolution is always an unevaluated context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);

// Add this candidate
OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size());
Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none);
Candidate.Function = nullptr;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes);

// Determine the implicit conversion sequences for each of the
// arguments.
Candidate.Viable = true;
Candidate.ExplicitCallArguments = Args.size();
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
  // C++ [over.match.oper]p4:
  //   For the built-in assignment operators, conversions of the
  //   left operand are restricted as follows:
  //     -- no temporaries are introduced to hold the left operand, and
  //     -- no user-defined conversions are applied to the left
  //        operand to achieve a type match with the left-most
  //        parameter of a built-in candidate.
  //
  // We block these conversions by turning off user-defined
  // conversions, since that is the only way that initialization of
  // a reference to a non-class type can occur from something that
  // is not of the same type.
  if (ArgIdx < NumContextualBoolArguments) {
    assert(ParamTys[ArgIdx] == Context.BoolTy &&((void)0)
           "Contextual conversion to bool requires bool type")((void)0);
    Candidate.Conversions[ArgIdx]
      = TryContextuallyConvertToBool(*this, Args[ArgIdx]);
  } else {
    Candidate.Conversions[ArgIdx]
      = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx],
                              ArgIdx == 0 && IsAssignmentOperator,
                              /*InOverloadResolution=*/false,
                              /*AllowObjCWritebackConversion=*/
                                getLangOpts().ObjCAutoRefCount);
  }
  if (Candidate.Conversions[ArgIdx].isBad()) {
    Candidate.Viable = false;
    Candidate.FailureKind = ovl_fail_bad_conversion;
    break;
  }
}
7767}

7769namespace {

7771/// BuiltinCandidateTypeSet - A set of types that will be used for the
7772/// candidate operator functions for built-in operators (C++
7773/// [over.built]). The types are separated into pointer types and
7774/// enumeration types.
7775class BuiltinCandidateTypeSet  {
/// TypeSet - A set of types.
typedef llvm::SetVector<QualType, SmallVector<QualType, 8>,
                        llvm::SmallPtrSet<QualType, 8>> TypeSet;

/// PointerTypes - The set of pointer types that will be used in the
/// built-in candidates.
TypeSet PointerTypes;

/// MemberPointerTypes - The set of member pointer types that will be
/// used in the built-in candidates.
TypeSet MemberPointerTypes;

/// EnumerationTypes - The set of enumeration types that will be
/// used in the built-in candidates.
TypeSet EnumerationTypes;

/// The set of vector types that will be used in the built-in
/// candidates.
TypeSet VectorTypes;

/// The set of matrix types that will be used in the built-in
/// candidates.
TypeSet MatrixTypes;

/// A flag indicating non-record types are viable candidates
bool HasNonRecordTypes;

/// A flag indicating whether either arithmetic or enumeration types
/// were present in the candidate set.
bool HasArithmeticOrEnumeralTypes;

/// A flag indicating whether the nullptr type was present in the
/// candidate set.
bool HasNullPtrType;

/// Sema - The semantic analysis instance where we are building the
/// candidate type set.
Sema &SemaRef;

/// Context - The AST context in which we will build the type sets.
ASTContext &Context;

bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
                                             const Qualifiers &VisibleQuals);
bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty);

7822public:
/// iterator - Iterates through the types that are part of the set.
typedef TypeSet::iterator iterator;

BuiltinCandidateTypeSet(Sema &SemaRef)
  : HasNonRecordTypes(false),
    HasArithmeticOrEnumeralTypes(false),
    HasNullPtrType(false),
    SemaRef(SemaRef),
    Context(SemaRef.Context) { }

void AddTypesConvertedFrom(QualType Ty,
                           SourceLocation Loc,
                           bool AllowUserConversions,
                           bool AllowExplicitConversions,
                           const Qualifiers &VisibleTypeConversionsQuals);

llvm::iterator_range<iterator> pointer_types() { return PointerTypes; }
llvm::iterator_range<iterator> member_pointer_types() {
  return MemberPointerTypes;
}
llvm::iterator_range<iterator> enumeration_types() {
  return EnumerationTypes;
}
llvm::iterator_range<iterator> vector_types() { return VectorTypes; }
llvm::iterator_range<iterator> matrix_types() { return MatrixTypes; }

bool containsMatrixType(QualType Ty) const { return MatrixTypes.count(Ty); }
bool hasNonRecordTypes() { return HasNonRecordTypes; }
bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; }
bool hasNullPtrType() const { return HasNullPtrType; }
7853};

7855} // end anonymous namespace

7857/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to
7858/// the set of pointer types along with any more-qualified variants of
7859/// that type. For example, if @p Ty is "int const *", this routine
7860/// will add "int const *", "int const volatile *", "int const
7861/// restrict *", and "int const volatile restrict *" to the set of
7862/// pointer types. Returns true if the add of @p Ty itself succeeded,
7863/// false otherwise.
7864///
7865/// FIXME: what to do about extended qualifiers?
7866bool
7867BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
                                           const Qualifiers &VisibleQuals) {

// Insert this type.
if (!PointerTypes.insert(Ty))
  return false;

QualType PointeeTy;
const PointerType *PointerTy = Ty->getAs<PointerType>();
bool buildObjCPtr = false;
if (!PointerTy) {
  const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>();
  PointeeTy = PTy->getPointeeType();
  buildObjCPtr = true;
} else {
  PointeeTy = PointerTy->getPointeeType();
}

// Don't add qualified variants of arrays. For one, they're not allowed
// (the qualifier would sink to the element type), and for another, the
// only overload situation where it matters is subscript or pointer +- int,
// and those shouldn't have qualifier variants anyway.
if (PointeeTy->isArrayType())
  return true;

unsigned BaseCVR = PointeeTy.getCVRQualifiers();
bool hasVolatile = VisibleQuals.hasVolatile();
bool hasRestrict = VisibleQuals.hasRestrict();

// Iterate through all strict supersets of BaseCVR.
for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
  if ((CVR | BaseCVR) != CVR) continue;
  // Skip over volatile if no volatile found anywhere in the types.
  if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue;

  // Skip over restrict if no restrict found anywhere in the types, or if
  // the type cannot be restrict-qualified.
  if ((CVR & Qualifiers::Restrict) &&
      (!hasRestrict ||
       (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType()))))
    continue;

  // Build qualified pointee type.
  QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);

  // Build qualified pointer type.
  QualType QPointerTy;
  if (!buildObjCPtr)
    QPointerTy = Context.getPointerType(QPointeeTy);
  else
    QPointerTy = Context.getObjCObjectPointerType(QPointeeTy);

  // Insert qualified pointer type.
  PointerTypes.insert(QPointerTy);
}

return true;
7924}

7926/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty
7927/// to the set of pointer types along with any more-qualified variants of
7928/// that type. For example, if @p Ty is "int const *", this routine
7929/// will add "int const *", "int const volatile *", "int const
7930/// restrict *", and "int const volatile restrict *" to the set of
7931/// pointer types. Returns true if the add of @p Ty itself succeeded,
7932/// false otherwise.
7933///
7934/// FIXME: what to do about extended qualifiers?
7935bool
7936BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants(
  QualType Ty) {
// Insert this type.
if (!MemberPointerTypes.insert(Ty))
  return false;

const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>();
assert(PointerTy && "type was not a member pointer type!")((void)0);

QualType PointeeTy = PointerTy->getPointeeType();
// Don't add qualified variants of arrays. For one, they're not allowed
// (the qualifier would sink to the element type), and for another, the
// only overload situation where it matters is subscript or pointer +- int,
// and those shouldn't have qualifier variants anyway.
if (PointeeTy->isArrayType())
  return true;
const Type *ClassTy = PointerTy->getClass();

// Iterate through all strict supersets of the pointee type's CVR
// qualifiers.
unsigned BaseCVR = PointeeTy.getCVRQualifiers();
for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
  if ((CVR | BaseCVR) != CVR) continue;

  QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
  MemberPointerTypes.insert(
    Context.getMemberPointerType(QPointeeTy, ClassTy));
}

return true;
7966}

7968/// AddTypesConvertedFrom - Add each of the types to which the type @p
7969/// Ty can be implicit converted to the given set of @p Types. We're
7970/// primarily interested in pointer types and enumeration types. We also
7971/// take member pointer types, for the conditional operator.
7972/// AllowUserConversions is true if we should look at the conversion
7973/// functions of a class type, and AllowExplicitConversions if we
7974/// should also include the explicit conversion functions of a class
7975/// type.
7976void
7977BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty,
                                             SourceLocation Loc,
                                             bool AllowUserConversions,
                                             bool AllowExplicitConversions,
                                             const Qualifiers &VisibleQuals) {
// Only deal with canonical types.
Ty = Context.getCanonicalType(Ty);

// Look through reference types; they aren't part of the type of an
// expression for the purposes of conversions.
if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>())
  Ty = RefTy->getPointeeType();

// If we're dealing with an array type, decay to the pointer.
if (Ty->isArrayType())
  Ty = SemaRef.Context.getArrayDecayedType(Ty);

// Otherwise, we don't care about qualifiers on the type.
Ty = Ty.getLocalUnqualifiedType();

// Flag if we ever add a non-record type.
const RecordType *TyRec = Ty->getAs<RecordType>();
HasNonRecordTypes = HasNonRecordTypes || !TyRec;

// Flag if we encounter an arithmetic type.
HasArithmeticOrEnumeralTypes =
  HasArithmeticOrEnumeralTypes || Ty->isArithmeticType();

if (Ty->isObjCIdType() || Ty->isObjCClassType())
  PointerTypes.insert(Ty);
else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) {
  // Insert our type, and its more-qualified variants, into the set
  // of types.
  if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals))
    return;
} else if (Ty->isMemberPointerType()) {
  // Member pointers are far easier, since the pointee can't be converted.
  if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty))
    return;
} else if (Ty->isEnumeralType()) {
  HasArithmeticOrEnumeralTypes = true;
  EnumerationTypes.insert(Ty);
} else if (Ty->isVectorType()) {
  // We treat vector types as arithmetic types in many contexts as an
  // extension.
  HasArithmeticOrEnumeralTypes = true;
  VectorTypes.insert(Ty);
} else if (Ty->isMatrixType()) {
  // Similar to vector types, we treat vector types as arithmetic types in
  // many contexts as an extension.
  HasArithmeticOrEnumeralTypes = true;
  MatrixTypes.insert(Ty);
} else if (Ty->isNullPtrType()) {
  HasNullPtrType = true;
} else if (AllowUserConversions && TyRec) {
  // No conversion functions in incomplete types.
  if (!SemaRef.isCompleteType(Loc, Ty))
    return;

  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
  for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
    if (isa<UsingShadowDecl>(D))
      D = cast<UsingShadowDecl>(D)->getTargetDecl();

    // Skip conversion function templates; they don't tell us anything
    // about which builtin types we can convert to.
    if (isa<FunctionTemplateDecl>(D))
      continue;

    CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
    if (AllowExplicitConversions || !Conv->isExplicit()) {
      AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false,
                            VisibleQuals);
    }
  }
}
8053}
8054/// Helper function for adjusting address spaces for the pointer or reference
8055/// operands of builtin operators depending on the argument.
8056static QualType AdjustAddressSpaceForBuiltinOperandType(Sema &S, QualType T,
                                                      Expr *Arg) {
return S.Context.getAddrSpaceQualType(T, Arg->getType().getAddressSpace());
8059}

8061/// Helper function for AddBuiltinOperatorCandidates() that adds
8062/// the volatile- and non-volatile-qualified assignment operators for the
8063/// given type to the candidate set.
8064static void AddBuiltinAssignmentOperatorCandidates(Sema &S,
                                                 QualType T,
                                                 ArrayRef<Expr *> Args,
                                  OverloadCandidateSet &CandidateSet) {
QualType ParamTypes[2];

// T& operator=(T&, T)
ParamTypes[0] = S.Context.getLValueReferenceType(
    AdjustAddressSpaceForBuiltinOperandType(S, T, Args[0]));
ParamTypes[1] = T;
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                      /*IsAssignmentOperator=*/true);

if (!S.Context.getCanonicalType(T).isVolatileQualified()) {
  // volatile T& operator=(volatile T&, T)
  ParamTypes[0] = S.Context.getLValueReferenceType(
      AdjustAddressSpaceForBuiltinOperandType(S, S.Context.getVolatileType(T),
                                              Args[0]));
  ParamTypes[1] = T;
  S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                        /*IsAssignmentOperator=*/true);
}
8086}

8088/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers,
8089/// if any, found in visible type conversion functions found in ArgExpr's type.
8090static  Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) {
  Qualifiers VRQuals;
  const RecordType *TyRec;
  if (const MemberPointerType *RHSMPType =
      ArgExpr->getType()->getAs<MemberPointerType>())
    TyRec = RHSMPType->getClass()->getAs<RecordType>();
  else
    TyRec = ArgExpr->getType()->getAs<RecordType>();
  if (!TyRec) {
    // Just to be safe, assume the worst case.
    VRQuals.addVolatile();
    VRQuals.addRestrict();
    return VRQuals;
  }

  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
  if (!ClassDecl->hasDefinition())
    return VRQuals;

  for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
    if (isa<UsingShadowDecl>(D))
      D = cast<UsingShadowDecl>(D)->getTargetDecl();
    if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) {
      QualType CanTy = Context.getCanonicalType(Conv->getConversionType());
      if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>())
        CanTy = ResTypeRef->getPointeeType();
      // Need to go down the pointer/mempointer chain and add qualifiers
      // as see them.
      bool done = false;
      while (!done) {
        if (CanTy.isRestrictQualified())
          VRQuals.addRestrict();
        if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>())
          CanTy = ResTypePtr->getPointeeType();
        else if (const MemberPointerType *ResTypeMPtr =
              CanTy->getAs<MemberPointerType>())
          CanTy = ResTypeMPtr->getPointeeType();
        else
          done = true;
        if (CanTy.isVolatileQualified())
          VRQuals.addVolatile();
        if (VRQuals.hasRestrict() && VRQuals.hasVolatile())
          return VRQuals;
      }
    }
  }
  return VRQuals;
8137}

8139namespace {

8141/// Helper class to manage the addition of builtin operator overload
8142/// candidates. It provides shared state and utility methods used throughout
8143/// the process, as well as a helper method to add each group of builtin
8144/// operator overloads from the standard to a candidate set.
8145class BuiltinOperatorOverloadBuilder {
// Common instance state available to all overload candidate addition methods.
Sema &S;
ArrayRef<Expr *> Args;
Qualifiers VisibleTypeConversionsQuals;
bool HasArithmeticOrEnumeralCandidateType;
SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes;
OverloadCandidateSet &CandidateSet;

static constexpr int ArithmeticTypesCap = 24;
SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes;

// Define some indices used to iterate over the arithmetic types in
// ArithmeticTypes.  The "promoted arithmetic types" are the arithmetic
// types are that preserved by promotion (C++ [over.built]p2).
unsigned FirstIntegralType,
         LastIntegralType;
unsigned FirstPromotedIntegralType,
         LastPromotedIntegralType;
unsigned FirstPromotedArithmeticType,
         LastPromotedArithmeticType;
unsigned NumArithmeticTypes;

void InitArithmeticTypes() {
  // Start of promoted types.
  FirstPromotedArithmeticType = 0;
  ArithmeticTypes.push_back(S.Context.FloatTy);
  ArithmeticTypes.push_back(S.Context.DoubleTy);
  ArithmeticTypes.push_back(S.Context.LongDoubleTy);
  if (S.Context.getTargetInfo().hasFloat128Type())
    ArithmeticTypes.push_back(S.Context.Float128Ty);

  // Start of integral types.
  FirstIntegralType = ArithmeticTypes.size();
  FirstPromotedIntegralType = ArithmeticTypes.size();
  ArithmeticTypes.push_back(S.Context.IntTy);
  ArithmeticTypes.push_back(S.Context.LongTy);
  ArithmeticTypes.push_back(S.Context.LongLongTy);
  if (S.Context.getTargetInfo().hasInt128Type() ||
      (S.Context.getAuxTargetInfo() &&
       S.Context.getAuxTargetInfo()->hasInt128Type()))
    ArithmeticTypes.push_back(S.Context.Int128Ty);
  ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
  ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
  ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
  if (S.Context.getTargetInfo().hasInt128Type() ||
      (S.Context.getAuxTargetInfo() &&
       S.Context.getAuxTargetInfo()->hasInt128Type()))
    ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
  LastPromotedIntegralType = ArithmeticTypes.size();
  LastPromotedArithmeticType = ArithmeticTypes.size();
  // End of promoted types.

  ArithmeticTypes.push_back(S.Context.BoolTy);
  ArithmeticTypes.push_back(S.Context.CharTy);
  ArithmeticTypes.push_back(S.Context.WCharTy);
  if (S.Context.getLangOpts().Char8)
    ArithmeticTypes.push_back(S.Context.Char8Ty);
  ArithmeticTypes.push_back(S.Context.Char16Ty);
  ArithmeticTypes.push_back(S.Context.Char32Ty);
  ArithmeticTypes.push_back(S.Context.SignedCharTy);
  ArithmeticTypes.push_back(S.Context.ShortTy);
  ArithmeticTypes.push_back(S.Context.UnsignedCharTy);
  ArithmeticTypes.push_back(S.Context.UnsignedShortTy);
  LastIntegralType = ArithmeticTypes.size();
  NumArithmeticTypes = ArithmeticTypes.size();
  // End of integral types.
  // FIXME: What about complex? What about half?

  assert(ArithmeticTypes.size() <= ArithmeticTypesCap &&((void)0)
         "Enough inline storage for all arithmetic types.")((void)0);
}

/// Helper method to factor out the common pattern of adding overloads
/// for '++' and '--' builtin operators.
void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,
                                         bool HasVolatile,
                                         bool HasRestrict) {
  QualType ParamTypes[2] = {
    S.Context.getLValueReferenceType(CandidateTy),
    S.Context.IntTy
  };

  // Non-volatile version.
  S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);

  // Use a heuristic to reduce number of builtin candidates in the set:
  // add volatile version only if there are conversions to a volatile type.
  if (HasVolatile) {
    ParamTypes[0] =
      S.Context.getLValueReferenceType(
        S.Context.getVolatileType(CandidateTy));
    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
  }

  // Add restrict version only if there are conversions to a restrict type
  // and our candidate type is a non-restrict-qualified pointer.
  if (HasRestrict && CandidateTy->isAnyPointerType() &&
      !CandidateTy.isRestrictQualified()) {
    ParamTypes[0]
      = S.Context.getLValueReferenceType(
          S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict));
    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);

    if (HasVolatile) {
      ParamTypes[0]
        = S.Context.getLValueReferenceType(
            S.Context.getCVRQualifiedType(CandidateTy,
                                          (Qualifiers::Volatile |
                                           Qualifiers::Restrict)));
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }
  }

}

/// Helper to add an overload candidate for a binary builtin with types \p L
/// and \p R.
void AddCandidate(QualType L, QualType R) {
  QualType LandR[2] = {L, R};
  S.AddBuiltinCandidate(LandR, Args, CandidateSet);
}

8268public:
BuiltinOperatorOverloadBuilder(
  Sema &S, ArrayRef<Expr *> Args,
  Qualifiers VisibleTypeConversionsQuals,
  bool HasArithmeticOrEnumeralCandidateType,
  SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes,
  OverloadCandidateSet &CandidateSet)
  : S(S), Args(Args),
    VisibleTypeConversionsQuals(VisibleTypeConversionsQuals),
    HasArithmeticOrEnumeralCandidateType(
      HasArithmeticOrEnumeralCandidateType),
    CandidateTypes(CandidateTypes),
    CandidateSet(CandidateSet) {

  InitArithmeticTypes();
}

// Increment is deprecated for bool since C++17.
//
// C++ [over.built]p3:
//
//   For every pair (T, VQ), where T is an arithmetic type other
//   than bool, and VQ is either volatile or empty, there exist
//   candidate operator functions of the form
//
//       VQ T&      operator++(VQ T&);
//       T          operator++(VQ T&, int);
//
// C++ [over.built]p4:
//
//   For every pair (T, VQ), where T is an arithmetic type other
//   than bool, and VQ is either volatile or empty, there exist
//   candidate operator functions of the form
//
//       VQ T&      operator--(VQ T&);
//       T          operator--(VQ T&, int);
void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
    const auto TypeOfT = ArithmeticTypes[Arith];
    if (TypeOfT == S.Context.BoolTy) {
      if (Op == OO_MinusMinus)
        continue;
      if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17)
        continue;
    }
    addPlusPlusMinusMinusStyleOverloads(
      TypeOfT,
      VisibleTypeConversionsQuals.hasVolatile(),
      VisibleTypeConversionsQuals.hasRestrict());
  }
}

// C++ [over.built]p5:
//
//   For every pair (T, VQ), where T is a cv-qualified or
//   cv-unqualified object type, and VQ is either volatile or
//   empty, there exist candidate operator functions of the form
//
//       T*VQ&      operator++(T*VQ&);
//       T*VQ&      operator--(T*VQ&);
//       T*         operator++(T*VQ&, int);
//       T*         operator--(T*VQ&, int);
void addPlusPlusMinusMinusPointerOverloads() {
  for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
    // Skip pointer types that aren't pointers to object types.
    if (!PtrTy->getPointeeType()->isObjectType())
      continue;

    addPlusPlusMinusMinusStyleOverloads(
        PtrTy,
        (!PtrTy.isVolatileQualified() &&
         VisibleTypeConversionsQuals.hasVolatile()),
        (!PtrTy.isRestrictQualified() &&
         VisibleTypeConversionsQuals.hasRestrict()));
  }
}

// C++ [over.built]p6:
//   For every cv-qualified or cv-unqualified object type T, there
//   exist candidate operator functions of the form
//
//       T&         operator*(T*);
//
// C++ [over.built]p7:
//   For every function type T that does not have cv-qualifiers or a
//   ref-qualifier, there exist candidate operator functions of the form
//       T&         operator*(T*);
void addUnaryStarPointerOverloads() {
  for (QualType ParamTy : CandidateTypes[0].pointer_types()) {
    QualType PointeeTy = ParamTy->getPointeeType();
    if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType())
      continue;

    if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>())
      if (Proto->getMethodQuals() || Proto->getRefQualifier())
        continue;

    S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
  }
}

// C++ [over.built]p9:
//  For every promoted arithmetic type T, there exist candidate
//  operator functions of the form
//
//       T         operator+(T);
//       T         operator-(T);
void addUnaryPlusOrMinusArithmeticOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Arith = FirstPromotedArithmeticType;
       Arith < LastPromotedArithmeticType; ++Arith) {
    QualType ArithTy = ArithmeticTypes[Arith];
    S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet);
  }

  // Extension: We also add these operators for vector types.
  for (QualType VecTy : CandidateTypes[0].vector_types())
    S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
}

// C++ [over.built]p8:
//   For every type T, there exist candidate operator functions of
//   the form
//
//       T*         operator+(T*);
void addUnaryPlusPointerOverloads() {
  for (QualType ParamTy : CandidateTypes[0].pointer_types())
    S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
}

// C++ [over.built]p10:
//   For every promoted integral type T, there exist candidate
//   operator functions of the form
//
//        T         operator~(T);
void addUnaryTildePromotedIntegralOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Int = FirstPromotedIntegralType;
       Int < LastPromotedIntegralType; ++Int) {
    QualType IntTy = ArithmeticTypes[Int];
    S.AddBuiltinCandidate(&IntTy, Args, CandidateSet);
  }

  // Extension: We also add this operator for vector types.
  for (QualType VecTy : CandidateTypes[0].vector_types())
    S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
}

// C++ [over.match.oper]p16:
//   For every pointer to member type T or type std::nullptr_t, there
//   exist candidate operator functions of the form
//
//        bool operator==(T,T);
//        bool operator!=(T,T);
void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() {
  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
    for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
      // Don't add the same builtin candidate twice.
      if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
        continue;

      QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }

    if (CandidateTypes[ArgIdx].hasNullPtrType()) {
      CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy);
      if (AddedTypes.insert(NullPtrTy).second) {
        QualType ParamTypes[2] = { NullPtrTy, NullPtrTy };
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
      }
    }
  }
}

// C++ [over.built]p15:
//
//   For every T, where T is an enumeration type or a pointer type,
//   there exist candidate operator functions of the form
//
//        bool       operator<(T, T);
//        bool       operator>(T, T);
//        bool       operator<=(T, T);
//        bool       operator>=(T, T);
//        bool       operator==(T, T);
//        bool       operator!=(T, T);
//           R       operator<=>(T, T)
void addGenericBinaryPointerOrEnumeralOverloads(bool IsSpaceship) {
  // C++ [over.match.oper]p3:
  //   [...]the built-in candidates include all of the candidate operator
  //   functions defined in 13.6 that, compared to the given operator, [...]
  //   do not have the same parameter-type-list as any non-template non-member
  //   candidate.
  //
  // Note that in practice, this only affects enumeration types because there
  // aren't any built-in candidates of record type, and a user-defined operator
  // must have an operand of record or enumeration type. Also, the only other
  // overloaded operator with enumeration arguments, operator=,
  // cannot be overloaded for enumeration types, so this is the only place
  // where we must suppress candidates like this.
  llvm::DenseSet<std::pair<CanQualType, CanQualType> >
    UserDefinedBinaryOperators;

  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
    if (!CandidateTypes[ArgIdx].enumeration_types().empty()) {
      for (OverloadCandidateSet::iterator C = CandidateSet.begin(),
                                       CEnd = CandidateSet.end();
           C != CEnd; ++C) {
        if (!C->Viable || !C->Function || C->Function->getNumParams() != 2)
          continue;

        if (C->Function->isFunctionTemplateSpecialization())
          continue;

        // We interpret "same parameter-type-list" as applying to the
        // "synthesized candidate, with the order of the two parameters
        // reversed", not to the original function.
        bool Reversed = C->isReversed();
        QualType FirstParamType = C->Function->getParamDecl(Reversed ? 1 : 0)
                                      ->getType()
                                      .getUnqualifiedType();
        QualType SecondParamType = C->Function->getParamDecl(Reversed ? 0 : 1)
                                       ->getType()
                                       .getUnqualifiedType();

        // Skip if either parameter isn't of enumeral type.
        if (!FirstParamType->isEnumeralType() ||
            !SecondParamType->isEnumeralType())
          continue;

        // Add this operator to the set of known user-defined operators.
        UserDefinedBinaryOperators.insert(
          std::make_pair(S.Context.getCanonicalType(FirstParamType),
                         S.Context.getCanonicalType(SecondParamType)));
      }
    }
  }

  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
    for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
      // Don't add the same builtin candidate twice.
      if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
        continue;
      if (IsSpaceship && PtrTy->isFunctionPointerType())
        continue;

      QualType ParamTypes[2] = {PtrTy, PtrTy};
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }
    for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
      CanQualType CanonType = S.Context.getCanonicalType(EnumTy);

      // Don't add the same builtin candidate twice, or if a user defined
      // candidate exists.
      if (!AddedTypes.insert(CanonType).second ||
          UserDefinedBinaryOperators.count(std::make_pair(CanonType,
                                                          CanonType)))
        continue;
      QualType ParamTypes[2] = {EnumTy, EnumTy};
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }
  }
}

// C++ [over.built]p13:
//
//   For every cv-qualified or cv-unqualified object type T
//   there exist candidate operator functions of the form
//
//      T*         operator+(T*, ptrdiff_t);
//      T&         operator[](T*, ptrdiff_t);    [BELOW]
//      T*         operator-(T*, ptrdiff_t);
//      T*         operator+(ptrdiff_t, T*);
//      T&         operator[](ptrdiff_t, T*);    [BELOW]
//
// C++ [over.built]p14:
//
//   For every T, where T is a pointer to object type, there
//   exist candidate operator functions of the form
//
//      ptrdiff_t  operator-(T, T);
void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) {
  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (int Arg = 0; Arg < 2; ++Arg) {
    QualType AsymmetricParamTypes[2] = {
      S.Context.getPointerDiffType(),
      S.Context.getPointerDiffType(),
    };
    for (QualType PtrTy : CandidateTypes[Arg].pointer_types()) {
      QualType PointeeTy = PtrTy->getPointeeType();
      if (!PointeeTy->isObjectType())
        continue;

      AsymmetricParamTypes[Arg] = PtrTy;
      if (Arg == 0 || Op == OO_Plus) {
        // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t)
        // T* operator+(ptrdiff_t, T*);
        S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet);
      }
      if (Op == OO_Minus) {
        // ptrdiff_t operator-(T, T);
        if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
          continue;

        QualType ParamTypes[2] = {PtrTy, PtrTy};
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
      }
    }
  }
}

// C++ [over.built]p12:
//
//   For every pair of promoted arithmetic types L and R, there
//   exist candidate operator functions of the form
//
//        LR         operator*(L, R);
//        LR         operator/(L, R);
//        LR         operator+(L, R);
//        LR         operator-(L, R);
//        bool       operator<(L, R);
//        bool       operator>(L, R);
//        bool       operator<=(L, R);
//        bool       operator>=(L, R);
//        bool       operator==(L, R);
//        bool       operator!=(L, R);
//
//   where LR is the result of the usual arithmetic conversions
//   between types L and R.
//
// C++ [over.built]p24:
//
//   For every pair of promoted arithmetic types L and R, there exist
//   candidate operator functions of the form
//
//        LR       operator?(bool, L, R);
//
//   where LR is the result of the usual arithmetic conversions
//   between types L and R.
// Our candidates ignore the first parameter.
void addGenericBinaryArithmeticOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Left = FirstPromotedArithmeticType;
       Left < LastPromotedArithmeticType; ++Left) {
    for (unsigned Right = FirstPromotedArithmeticType;
         Right < LastPromotedArithmeticType; ++Right) {
      QualType LandR[2] = { ArithmeticTypes[Left],
                            ArithmeticTypes[Right] };
      S.AddBuiltinCandidate(LandR, Args, CandidateSet);
    }
  }

  // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the
  // conditional operator for vector types.
  for (QualType Vec1Ty : CandidateTypes[0].vector_types())
    for (QualType Vec2Ty : CandidateTypes[1].vector_types()) {
      QualType LandR[2] = {Vec1Ty, Vec2Ty};
      S.AddBuiltinCandidate(LandR, Args, CandidateSet);
    }
}

/// Add binary operator overloads for each candidate matrix type M1, M2:
///  * (M1, M1) -> M1
///  * (M1, M1.getElementType()) -> M1
///  * (M2.getElementType(), M2) -> M2
///  * (M2, M2) -> M2 // Only if M2 is not part of CandidateTypes[0].
void addMatrixBinaryArithmeticOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (QualType M1 : CandidateTypes[0].matrix_types()) {
    AddCandidate(M1, cast<MatrixType>(M1)->getElementType());
    AddCandidate(M1, M1);
  }

  for (QualType M2 : CandidateTypes[1].matrix_types()) {
    AddCandidate(cast<MatrixType>(M2)->getElementType(), M2);
    if (!CandidateTypes[0].containsMatrixType(M2))
      AddCandidate(M2, M2);
  }
}

// C++2a [over.built]p14:
//
//   For every integral type T there exists a candidate operator function
//   of the form
//
//        std::strong_ordering operator<=>(T, T)
//
// C++2a [over.built]p15:
//
//   For every pair of floating-point types L and R, there exists a candidate
//   operator function of the form
//
//       std::partial_ordering operator<=>(L, R);
//
// FIXME: The current specification for integral types doesn't play nice with
// the direction of p0946r0, which allows mixed integral and unscoped-enum
// comparisons. Under the current spec this can lead to ambiguity during
// overload resolution. For example:
//
//   enum A : int {a};
//   auto x = (a <=> (long)42);
//
//   error: call is ambiguous for arguments 'A' and 'long'.
//   note: candidate operator<=>(int, int)
//   note: candidate operator<=>(long, long)
//
// To avoid this error, this function deviates from the specification and adds
// the mixed overloads `operator<=>(L, R)` where L and R are promoted
// arithmetic types (the same as the generic relational overloads).
//
// For now this function acts as a placeholder.
void addThreeWayArithmeticOverloads() {
  addGenericBinaryArithmeticOverloads();
}

// C++ [over.built]p17:
//
//   For every pair of promoted integral types L and R, there
//   exist candidate operator functions of the form
//
//      LR         operator%(L, R);
//      LR         operator&(L, R);
//      LR         operator^(L, R);
//      LR         operator|(L, R);
//      L          operator<<(L, R);
//      L          operator>>(L, R);
//
//   where LR is the result of the usual arithmetic conversions
//   between types L and R.
void addBinaryBitwiseArithmeticOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Left = FirstPromotedIntegralType;
       Left < LastPromotedIntegralType; ++Left) {
    for (unsigned Right = FirstPromotedIntegralType;
         Right < LastPromotedIntegralType; ++Right) {
      QualType LandR[2] = { ArithmeticTypes[Left],
                            ArithmeticTypes[Right] };
      S.AddBuiltinCandidate(LandR, Args, CandidateSet);
    }
  }
}

// C++ [over.built]p20:
//
//   For every pair (T, VQ), where T is an enumeration or
//   pointer to member type and VQ is either volatile or
//   empty, there exist candidate operator functions of the form
//
//        VQ T&      operator=(VQ T&, T);
void addAssignmentMemberPointerOrEnumeralOverloads() {
  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
    for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
      if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
        continue;

      AddBuiltinAssignmentOperatorCandidates(S, EnumTy, Args, CandidateSet);
    }

    for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
      if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
        continue;

      AddBuiltinAssignmentOperatorCandidates(S, MemPtrTy, Args, CandidateSet);
    }
  }
}

// C++ [over.built]p19:
//
//   For every pair (T, VQ), where T is any type and VQ is either
//   volatile or empty, there exist candidate operator functions
//   of the form
//
//        T*VQ&      operator=(T*VQ&, T*);
//
// C++ [over.built]p21:
//
//   For every pair (T, VQ), where T is a cv-qualified or
//   cv-unqualified object type and VQ is either volatile or
//   empty, there exist candidate operator functions of the form
//
//        T*VQ&      operator+=(T*VQ&, ptrdiff_t);
//        T*VQ&      operator-=(T*VQ&, ptrdiff_t);
void addAssignmentPointerOverloads(bool isEqualOp) {
  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
    // If this is operator=, keep track of the builtin candidates we added.
    if (isEqualOp)
      AddedTypes.insert(S.Context.getCanonicalType(PtrTy));
    else if (!PtrTy->getPointeeType()->isObjectType())
      continue;

    // non-volatile version
    QualType ParamTypes[2] = {
        S.Context.getLValueReferenceType(PtrTy),
        isEqualOp ? PtrTy : S.Context.getPointerDiffType(),
    };
    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                          /*IsAssignmentOperator=*/ isEqualOp);

    bool NeedVolatile = !PtrTy.isVolatileQualified() &&
                        VisibleTypeConversionsQuals.hasVolatile();
    if (NeedVolatile) {
      // volatile version
      ParamTypes[0] =
          S.Context.getLValueReferenceType(S.Context.getVolatileType(PtrTy));
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                            /*IsAssignmentOperator=*/isEqualOp);
    }

    if (!PtrTy.isRestrictQualified() &&
        VisibleTypeConversionsQuals.hasRestrict()) {
      // restrict version
      ParamTypes[0] =
          S.Context.getLValueReferenceType(S.Context.getRestrictType(PtrTy));
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                            /*IsAssignmentOperator=*/isEqualOp);

      if (NeedVolatile) {
        // volatile restrict version
        ParamTypes[0] =
            S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
                PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                              /*IsAssignmentOperator=*/isEqualOp);
      }
    }
  }

  if (isEqualOp) {
    for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
      // Make sure we don't add the same candidate twice.
      if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
        continue;

      QualType ParamTypes[2] = {
          S.Context.getLValueReferenceType(PtrTy),
          PtrTy,
      };

      // non-volatile version
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                            /*IsAssignmentOperator=*/true);

      bool NeedVolatile = !PtrTy.isVolatileQualified() &&
                          VisibleTypeConversionsQuals.hasVolatile();
      if (NeedVolatile) {
        // volatile version
        ParamTypes[0] = S.Context.getLValueReferenceType(
            S.Context.getVolatileType(PtrTy));
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                              /*IsAssignmentOperator=*/true);
      }

      if (!PtrTy.isRestrictQualified() &&
          VisibleTypeConversionsQuals.hasRestrict()) {
        // restrict version
        ParamTypes[0] = S.Context.getLValueReferenceType(
            S.Context.getRestrictType(PtrTy));
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                              /*IsAssignmentOperator=*/true);

        if (NeedVolatile) {
          // volatile restrict version
          ParamTypes[0] =
              S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
                  PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                                /*IsAssignmentOperator=*/true);
        }
      }
    }
  }
}

// C++ [over.built]p18:
//
//   For every triple (L, VQ, R), where L is an arithmetic type,
//   VQ is either volatile or empty, and R is a promoted
//   arithmetic type, there exist candidate operator functions of
//   the form
//
//        VQ L&      operator=(VQ L&, R);
//        VQ L&      operator*=(VQ L&, R);
//        VQ L&      operator/=(VQ L&, R);
//        VQ L&      operator+=(VQ L&, R);
//        VQ L&      operator-=(VQ L&, R);
void addAssignmentArithmeticOverloads(bool isEqualOp) {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) {
    for (unsigned Right = FirstPromotedArithmeticType;
         Right < LastPromotedArithmeticType; ++Right) {
      QualType ParamTypes[2];
      ParamTypes[1] = ArithmeticTypes[Right];
      auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
          S, ArithmeticTypes[Left], Args[0]);
      // Add this built-in operator as a candidate (VQ is empty).
      ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                            /*IsAssignmentOperator=*/isEqualOp);

      // Add this built-in operator as a candidate (VQ is 'volatile').
      if (VisibleTypeConversionsQuals.hasVolatile()) {
        ParamTypes[0] = S.Context.getVolatileType(LeftBaseTy);
        ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                              /*IsAssignmentOperator=*/isEqualOp);
      }
    }
  }

  // Extension: Add the binary operators =, +=, -=, *=, /= for vector types.
  for (QualType Vec1Ty : CandidateTypes[0].vector_types())
    for (QualType Vec2Ty : CandidateTypes[0].vector_types()) {
      QualType ParamTypes[2];
      ParamTypes[1] = Vec2Ty;
      // Add this built-in operator as a candidate (VQ is empty).
      ParamTypes[0] = S.Context.getLValueReferenceType(Vec1Ty);
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                            /*IsAssignmentOperator=*/isEqualOp);

      // Add this built-in operator as a candidate (VQ is 'volatile').
      if (VisibleTypeConversionsQuals.hasVolatile()) {
        ParamTypes[0] = S.Context.getVolatileType(Vec1Ty);
        ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                              /*IsAssignmentOperator=*/isEqualOp);
      }
    }
}

// C++ [over.built]p22:
//
//   For every triple (L, VQ, R), where L is an integral type, VQ
//   is either volatile or empty, and R is a promoted integral
//   type, there exist candidate operator functions of the form
//
//        VQ L&       operator%=(VQ L&, R);
//        VQ L&       operator<<=(VQ L&, R);
//        VQ L&       operator>>=(VQ L&, R);
//        VQ L&       operator&=(VQ L&, R);
//        VQ L&       operator^=(VQ L&, R);
//        VQ L&       operator|=(VQ L&, R);
void addAssignmentIntegralOverloads() {
  if (!HasArithmeticOrEnumeralCandidateType)
    return;

  for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) {
    for (unsigned Right = FirstPromotedIntegralType;
         Right < LastPromotedIntegralType; ++Right) {
      QualType ParamTypes[2];
      ParamTypes[1] = ArithmeticTypes[Right];
      auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
          S, ArithmeticTypes[Left], Args[0]);
      // Add this built-in operator as a candidate (VQ is empty).
      ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
      if (VisibleTypeConversionsQuals.hasVolatile()) {
        // Add this built-in operator as a candidate (VQ is 'volatile').
        ParamTypes[0] = LeftBaseTy;
        ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]);
        ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
      }
    }
  }
}

// C++ [over.operator]p23:
//
//   There also exist candidate operator functions of the form
//
//        bool        operator!(bool);
//        bool        operator&&(bool, bool);
//        bool        operator||(bool, bool);
void addExclaimOverload() {
  QualType ParamTy = S.Context.BoolTy;
  S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet,
                        /*IsAssignmentOperator=*/false,
                        /*NumContextualBoolArguments=*/1);
}
void addAmpAmpOrPipePipeOverload() {
  QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy };
  S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
                        /*IsAssignmentOperator=*/false,
                        /*NumContextualBoolArguments=*/2);
}

// C++ [over.built]p13:
//
//   For every cv-qualified or cv-unqualified object type T there
//   exist candidate operator functions of the form
//
//        T*         operator+(T*, ptrdiff_t);     [ABOVE]
//        T&         operator[](T*, ptrdiff_t);
//        T*         operator-(T*, ptrdiff_t);     [ABOVE]
//        T*         operator+(ptrdiff_t, T*);     [ABOVE]
//        T&         operator[](ptrdiff_t, T*);
void addSubscriptOverloads() {
  for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
    QualType ParamTypes[2] = {PtrTy, S.Context.getPointerDiffType()};
    QualType PointeeType = PtrTy->getPointeeType();
    if (!PointeeType->isObjectType())
      continue;

    // T& operator[](T*, ptrdiff_t)
    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
  }

  for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
    QualType ParamTypes[2] = {S.Context.getPointerDiffType(), PtrTy};
    QualType PointeeType = PtrTy->getPointeeType();
    if (!PointeeType->isObjectType())
      continue;

    // T& operator[](ptrdiff_t, T*)
    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
  }
}

// C++ [over.built]p11:
//    For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type,
//    C1 is the same type as C2 or is a derived class of C2, T is an object
//    type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
//    there exist candidate operator functions of the form
//
//      CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
//
//    where CV12 is the union of CV1 and CV2.
void addArrowStarOverloads() {
  for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
    QualType C1Ty = PtrTy;
    QualType C1;
    QualifierCollector Q1;
    C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0);
    if (!isa<RecordType>(C1))
      continue;
    // heuristic to reduce number of builtin candidates in the set.
    // Add volatile/restrict version only if there are conversions to a
    // volatile/restrict type.
    if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile())
      continue;
    if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict())
      continue;
    for (QualType MemPtrTy : CandidateTypes[1].member_pointer_types()) {
      const MemberPointerType *mptr = cast<MemberPointerType>(MemPtrTy);
      QualType C2 = QualType(mptr->getClass(), 0);
      C2 = C2.getUnqualifiedType();
      if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2))
        break;
      QualType ParamTypes[2] = {PtrTy, MemPtrTy};
      // build CV12 T&
      QualType T = mptr->getPointeeType();
      if (!VisibleTypeConversionsQuals.hasVolatile() &&
          T.isVolatileQualified())
        continue;
      if (!VisibleTypeConversionsQuals.hasRestrict() &&
          T.isRestrictQualified())
        continue;
      T = Q1.apply(S.Context, T);
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }
  }
}

// Note that we don't consider the first argument, since it has been
// contextually converted to bool long ago. The candidates below are
// therefore added as binary.
//
// C++ [over.built]p25:
//   For every type T, where T is a pointer, pointer-to-member, or scoped
//   enumeration type, there exist candidate operator functions of the form
//
//        T        operator?(bool, T, T);
//
void addConditionalOperatorOverloads() {
  /// Set of (canonical) types that we've already handled.
  llvm::SmallPtrSet<QualType, 8> AddedTypes;

  for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
    for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
      if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
        continue;

      QualType ParamTypes[2] = {PtrTy, PtrTy};
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }

    for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
      if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
        continue;

      QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
    }

    if (S.getLangOpts().CPlusPlus11) {
      for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
        if (!EnumTy->castAs<EnumType>()->getDecl()->isScoped())
          continue;

        if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
          continue;

        QualType ParamTypes[2] = {EnumTy, EnumTy};
        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
      }
    }
  }
}
9106};

9108} // end anonymous namespace

9110/// AddBuiltinOperatorCandidates - Add the appropriate built-in
9111/// operator overloads to the candidate set (C++ [over.built]), based
9112/// on the operator @p Op and the arguments given. For example, if the
9113/// operator is a binary '+', this routine might add "int
9114/// operator+(int, int)" to cover integer addition.
9115void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
                                      SourceLocation OpLoc,
                                      ArrayRef<Expr *> Args,
                                      OverloadCandidateSet &CandidateSet) {
// Find all of the types that the arguments can convert to, but only
// if the operator we're looking at has built-in operator candidates
// that make use of these types. Also record whether we encounter non-record
// candidate types or either arithmetic or enumeral candidate types.
Qualifiers VisibleTypeConversionsQuals;
VisibleTypeConversionsQuals.addConst();
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx)
  VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]);

bool HasNonRecordCandidateType = false;
bool HasArithmeticOrEnumeralCandidateType = false;
SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes;
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
  CandidateTypes.emplace_back(*this);
  CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(),
                                               OpLoc,
                                               true,
                                               (Op == OO_Exclaim ||
                                                Op == OO_AmpAmp ||
                                                Op == OO_PipePipe),
                                               VisibleTypeConversionsQuals);
  HasNonRecordCandidateType = HasNonRecordCandidateType ||
      CandidateTypes[ArgIdx].hasNonRecordTypes();
  HasArithmeticOrEnumeralCandidateType =
      HasArithmeticOrEnumeralCandidateType ||
      CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes();
}

// Exit early when no non-record types have been added to the candidate set
// for any of the arguments to the operator.
//
// We can't exit early for !, ||, or &&, since there we have always have
// 'bool' overloads.
if (!HasNonRecordCandidateType &&
    !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe))
  return;

// Setup an object to manage the common state for building overloads.
BuiltinOperatorOverloadBuilder OpBuilder(*this, Args,
                                         VisibleTypeConversionsQuals,
                                         HasArithmeticOrEnumeralCandidateType,
                                         CandidateTypes, CandidateSet);

// Dispatch over the operation to add in only those overloads which apply.
switch (Op) {
case OO_None:
case NUM_OVERLOADED_OPERATORS:
  llvm_unreachable("Expected an overloaded operator")__builtin_unreachable();

case OO_New:
case OO_Delete:
case OO_Array_New:
case OO_Array_Delete:
case OO_Call:
  llvm_unreachable(__builtin_unreachable()
                  "Special operators don't use AddBuiltinOperatorCandidates")__builtin_unreachable();

case OO_Comma:
case OO_Arrow:
case OO_Coawait:
  // C++ [over.match.oper]p3:
  //   -- For the operator ',', the unary operator '&', the
  //      operator '->', or the operator 'co_await', the
  //      built-in candidates set is empty.
  break;

case OO_Plus: // '+' is either unary or binary
  if (Args.size() == 1)
    OpBuilder.addUnaryPlusPointerOverloads();
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case OO_Minus: // '-' is either unary or binary
  if (Args.size() == 1) {
    OpBuilder.addUnaryPlusOrMinusArithmeticOverloads();
  } else {
    OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op);
    OpBuilder.addGenericBinaryArithmeticOverloads();
    OpBuilder.addMatrixBinaryArithmeticOverloads();
  }
  break;

case OO_Star: // '*' is either unary or binary
  if (Args.size() == 1)
    OpBuilder.addUnaryStarPointerOverloads();
  else {
    OpBuilder.addGenericBinaryArithmeticOverloads();
    OpBuilder.addMatrixBinaryArithmeticOverloads();
  }
  break;

case OO_Slash:
  OpBuilder.addGenericBinaryArithmeticOverloads();
  break;

case OO_PlusPlus:
case OO_MinusMinus:
  OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op);
  OpBuilder.addPlusPlusMinusMinusPointerOverloads();
  break;

case OO_EqualEqual:
case OO_ExclaimEqual:
  OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
  OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
  OpBuilder.addGenericBinaryArithmeticOverloads();
  break;

case OO_Less:
case OO_Greater:
case OO_LessEqual:
case OO_GreaterEqual:
  OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
  OpBuilder.addGenericBinaryArithmeticOverloads();
  break;

case OO_Spaceship:
  OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/true);
  OpBuilder.addThreeWayArithmeticOverloads();
  break;

case OO_Percent:
case OO_Caret:
case OO_Pipe:
case OO_LessLess:
case OO_GreaterGreater:
  OpBuilder.addBinaryBitwiseArithmeticOverloads();
  break;

case OO_Amp: // '&' is either unary or binary
  if (Args.size() == 1)
    // C++ [over.match.oper]p3:
    //   -- For the operator ',', the unary operator '&', or the
    //      operator '->', the built-in candidates set is empty.
    break;

  OpBuilder.addBinaryBitwiseArithmeticOverloads();
  break;

case OO_Tilde:
  OpBuilder.addUnaryTildePromotedIntegralOverloads();
  break;

case OO_Equal:
  OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads();
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case OO_PlusEqual:
case OO_MinusEqual:
  OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case OO_StarEqual:
case OO_SlashEqual:
  OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal);
  break;

case OO_PercentEqual:
case OO_LessLessEqual:
case OO_GreaterGreaterEqual:
case OO_AmpEqual:
case OO_CaretEqual:
case OO_PipeEqual:
  OpBuilder.addAssignmentIntegralOverloads();
  break;

case OO_Exclaim:
  OpBuilder.addExclaimOverload();
  break;

case OO_AmpAmp:
case OO_PipePipe:
  OpBuilder.addAmpAmpOrPipePipeOverload();
  break;

case OO_Subscript:
  OpBuilder.addSubscriptOverloads();
  break;

case OO_ArrowStar:
  OpBuilder.addArrowStarOverloads();
  break;

case OO_Conditional:
  OpBuilder.addConditionalOperatorOverloads();
  OpBuilder.addGenericBinaryArithmeticOverloads();
  break;
}
9306}

9308/// Add function candidates found via argument-dependent lookup
9309/// to the set of overloading candidates.
9310///
9311/// This routine performs argument-dependent name lookup based on the
9312/// given function name (which may also be an operator name) and adds
9313/// all of the overload candidates found by ADL to the overload
9314/// candidate set (C++ [basic.lookup.argdep]).
9315void
9316Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
                                         SourceLocation Loc,
                                         ArrayRef<Expr *> Args,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                                         OverloadCandidateSet& CandidateSet,
                                         bool PartialOverloading) {
ADLResult Fns;

// FIXME: This approach for uniquing ADL results (and removing
// redundant candidates from the set) relies on pointer-equality,
// which means we need to key off the canonical decl.  However,
// always going back to the canonical decl might not get us the
// right set of default arguments.  What default arguments are
// we supposed to consider on ADL candidates, anyway?

// FIXME: Pass in the explicit template arguments?
ArgumentDependentLookup(Name, Loc, Args, Fns);

// Erase all of the candidates we already knew about.
for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
                                 CandEnd = CandidateSet.end();
     Cand != CandEnd; ++Cand)
  if (Cand->Function) {
    Fns.erase(Cand->Function);
    if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
      Fns.erase(FunTmpl);
  }

// For each of the ADL candidates we found, add it to the overload
// set.
for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
  DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none);

  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
    if (ExplicitTemplateArgs)
      continue;

    AddOverloadCandidate(
        FD, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false,
        PartialOverloading, /*AllowExplicit=*/true,
        /*AllowExplicitConversions=*/false, ADLCallKind::UsesADL);
    if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) {
      AddOverloadCandidate(
          FD, FoundDecl, {Args[1], Args[0]}, CandidateSet,
          /*SuppressUserConversions=*/false, PartialOverloading,
          /*AllowExplicit=*/true, /*AllowExplicitConversions=*/false,
          ADLCallKind::UsesADL, None, OverloadCandidateParamOrder::Reversed);
    }
  } else {
    auto *FTD = cast<FunctionTemplateDecl>(*I);
    AddTemplateOverloadCandidate(
        FTD, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet,
        /*SuppressUserConversions=*/false, PartialOverloading,
        /*AllowExplicit=*/true, ADLCallKind::UsesADL);
    if (CandidateSet.getRewriteInfo().shouldAddReversed(
            Context, FTD->getTemplatedDecl())) {
      AddTemplateOverloadCandidate(
          FTD, FoundDecl, ExplicitTemplateArgs, {Args[1], Args[0]},
          CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading,
          /*AllowExplicit=*/true, ADLCallKind::UsesADL,
          OverloadCandidateParamOrder::Reversed);
    }
  }
}
9380}

9382namespace {
9383enum class Comparison { Equal, Better, Worse };
9384}

9386/// Compares the enable_if attributes of two FunctionDecls, for the purposes of
9387/// overload resolution.
9388///
9389/// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff
9390/// Cand1's first N enable_if attributes have precisely the same conditions as
9391/// Cand2's first N enable_if attributes (where N = the number of enable_if
9392/// attributes on Cand2), and Cand1 has more than N enable_if attributes.
9393///
9394/// Note that you can have a pair of candidates such that Cand1's enable_if
9395/// attributes are worse than Cand2's, and Cand2's enable_if attributes are
9396/// worse than Cand1's.
9397static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1,
                                     const FunctionDecl *Cand2) {
// Common case: One (or both) decls don't have enable_if attrs.
bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>();
bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>();
if (!Cand1Attr || !Cand2Attr) {
  if (Cand1Attr == Cand2Attr)
    return Comparison::Equal;
  return Cand1Attr ? Comparison::Better : Comparison::Worse;
}

auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>();
auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>();

llvm::FoldingSetNodeID Cand1ID, Cand2ID;
for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) {
  Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
  Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);

  // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1
  // has fewer enable_if attributes than Cand2, and vice versa.
  if (!Cand1A)
    return Comparison::Worse;
  if (!Cand2A)
    return Comparison::Better;

  Cand1ID.clear();
  Cand2ID.clear();

  (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true);
  (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true);
  if (Cand1ID != Cand2ID)
    return Comparison::Worse;
}

return Comparison::Equal;
9433}

9435static Comparison
9436isBetterMultiversionCandidate(const OverloadCandidate &Cand1,
                            const OverloadCandidate &Cand2) {
if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function ||
    !Cand2.Function->isMultiVersion())
  return Comparison::Equal;

// If both are invalid, they are equal. If one of them is invalid, the other
// is better.
if (Cand1.Function->isInvalidDecl()) {
  if (Cand2.Function->isInvalidDecl())
    return Comparison::Equal;
  return Comparison::Worse;
}
if (Cand2.Function->isInvalidDecl())
  return Comparison::Better;

// If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
// cpu_dispatch, else arbitrarily based on the identifiers.
bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();
bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>();
const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>();
const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>();

if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec)
  return Comparison::Equal;

if (Cand1CPUDisp && !Cand2CPUDisp)
  return Comparison::Better;
if (Cand2CPUDisp && !Cand1CPUDisp)
  return Comparison::Worse;

if (Cand1CPUSpec && Cand2CPUSpec) {
  if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size())
    return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size()
               ? Comparison::Better
               : Comparison::Worse;

  std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator>
      FirstDiff = std::mismatch(
          Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(),
          Cand2CPUSpec->cpus_begin(),
          [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) {
            return LHS->getName() == RHS->getName();
          });

  assert(FirstDiff.first != Cand1CPUSpec->cpus_end() &&((void)0)
         "Two different cpu-specific versions should not have the same "((void)0)
         "identifier list, otherwise they'd be the same decl!")((void)0);
  return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName()
             ? Comparison::Better
             : Comparison::Worse;
}
llvm_unreachable("No way to get here unless both had cpu_dispatch")__builtin_unreachable();
9489}

9491/// Compute the type of the implicit object parameter for the given function,
9492/// if any. Returns None if there is no implicit object parameter, and a null
9493/// QualType if there is a 'matches anything' implicit object parameter.
9494static Optional<QualType> getImplicitObjectParamType(ASTContext &Context,
                                                   const FunctionDecl *F) {
if (!isa<CXXMethodDecl>(F) || isa<CXXConstructorDecl>(F))
  return llvm::None;

auto *M = cast<CXXMethodDecl>(F);
// Static member functions' object parameters match all types.
if (M->isStatic())
  return QualType();

QualType T = M->getThisObjectType();
if (M->getRefQualifier() == RQ_RValue)
  return Context.getRValueReferenceType(T);
return Context.getLValueReferenceType(T);
9508}

9510static bool haveSameParameterTypes(ASTContext &Context, const FunctionDecl *F1,
                                 const FunctionDecl *F2, unsigned NumParams) {
if (declaresSameEntity(F1, F2))
  return true;

auto NextParam = [&](const FunctionDecl *F, unsigned &I, bool First) {
  if (First) {
    if (Optional<QualType> T = getImplicitObjectParamType(Context, F))
      return *T;
  }
  assert(I < F->getNumParams())((void)0);
  return F->getParamDecl(I++)->getType();
};

unsigned I1 = 0, I2 = 0;
for (unsigned I = 0; I != NumParams; ++I) {
  QualType T1 = NextParam(F1, I1, I == 0);
  QualType T2 = NextParam(F2, I2, I == 0);
  if (!T1.isNull() && !T1.isNull() && !Context.hasSameUnqualifiedType(T1, T2))
    return false;
}
return true;
9532}

9534/// isBetterOverloadCandidate - Determines whether the first overload
9535/// candidate is a better candidate than the second (C++ 13.3.3p1).
9536bool clang::isBetterOverloadCandidate(
  Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2,
  SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) {
// Define viable functions to be better candidates than non-viable
// functions.
if (!Cand2.Viable)
  return Cand1.Viable;
else if (!Cand1.Viable)
  return false;

// [CUDA] A function with 'never' preference is marked not viable, therefore
// is never shown up here. The worst preference shown up here is 'wrong side',
// e.g. an H function called by a HD function in device compilation. This is
// valid AST as long as the HD function is not emitted, e.g. it is an inline
// function which is called only by an H function. A deferred diagnostic will
// be triggered if it is emitted. However a wrong-sided function is still
// a viable candidate here.
//
// If Cand1 can be emitted and Cand2 cannot be emitted in the current
// context, Cand1 is better than Cand2. If Cand1 can not be emitted and Cand2
// can be emitted, Cand1 is not better than Cand2. This rule should have
// precedence over other rules.
//
// If both Cand1 and Cand2 can be emitted, or neither can be emitted, then
// other rules should be used to determine which is better. This is because
// host/device based overloading resolution is mostly for determining
// viability of a function. If two functions are both viable, other factors
// should take precedence in preference, e.g. the standard-defined preferences
// like argument conversion ranks or enable_if partial-ordering. The
// preference for pass-object-size parameters is probably most similar to a
// type-based-overloading decision and so should take priority.
//
// If other rules cannot determine which is better, CUDA preference will be
// used again to determine which is better.
//
// TODO: Currently IdentifyCUDAPreference does not return correct values
// for functions called in global variable initializers due to missing
// correct context about device/host. Therefore we can only enforce this
// rule when there is a caller. We should enforce this rule for functions
// in global variable initializers once proper context is added.
//
// TODO: We can only enable the hostness based overloading resolution when
// -fgpu-exclude-wrong-side-overloads is on since this requires deferring
// overloading resolution diagnostics.
if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function &&
    S.getLangOpts().GPUExcludeWrongSideOverloads) {
  if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext)) {
    bool IsCallerImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Caller);
    bool IsCand1ImplicitHD =
        Sema::isCUDAImplicitHostDeviceFunction(Cand1.Function);
    bool IsCand2ImplicitHD =
        Sema::isCUDAImplicitHostDeviceFunction(Cand2.Function);
    auto P1 = S.IdentifyCUDAPreference(Caller, Cand1.Function);
    auto P2 = S.IdentifyCUDAPreference(Caller, Cand2.Function);
    assert(P1 != Sema::CFP_Never && P2 != Sema::CFP_Never)((void)0);
    // The implicit HD function may be a function in a system header which
    // is forced by pragma. In device compilation, if we prefer HD candidates
    // over wrong-sided candidates, overloading resolution may change, which
    // may result in non-deferrable diagnostics. As a workaround, we let
    // implicit HD candidates take equal preference as wrong-sided candidates.
    // This will preserve the overloading resolution.
    // TODO: We still need special handling of implicit HD functions since
    // they may incur other diagnostics to be deferred. We should make all
    // host/device related diagnostics deferrable and remove special handling
    // of implicit HD functions.
    auto EmitThreshold =
        (S.getLangOpts().CUDAIsDevice && IsCallerImplicitHD &&
         (IsCand1ImplicitHD || IsCand2ImplicitHD))
            ? Sema::CFP_Never
            : Sema::CFP_WrongSide;
    auto Cand1Emittable = P1 > EmitThreshold;
    auto Cand2Emittable = P2 > EmitThreshold;
    if (Cand1Emittable && !Cand2Emittable)
      return true;
    if (!Cand1Emittable && Cand2Emittable)
      return false;
  }
}

// C++ [over.match.best]p1:
//
//   -- if F is a static member function, ICS1(F) is defined such
//      that ICS1(F) is neither better nor worse than ICS1(G) for
//      any function G, and, symmetrically, ICS1(G) is neither
//      better nor worse than ICS1(F).
unsigned StartArg = 0;
if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument)
  StartArg = 1;

auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) {
  // We don't allow incompatible pointer conversions in C++.
  if (!S.getLangOpts().CPlusPlus)
    return ICS.isStandard() &&
           ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion;

  // The only ill-formed conversion we allow in C++ is the string literal to
  // char* conversion, which is only considered ill-formed after C++11.
  return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
         hasDeprecatedStringLiteralToCharPtrConversion(ICS);
};

// Define functions that don't require ill-formed conversions for a given
// argument to be better candidates than functions that do.
unsigned NumArgs = Cand1.Conversions.size();
assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch")((void)0);
bool HasBetterConversion = false;
for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
  bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]);
  bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]);
  if (Cand1Bad != Cand2Bad) {
    if (Cand1Bad)
      return false;
    HasBetterConversion = true;
  }
}

if (HasBetterConversion)
  return true;

// C++ [over.match.best]p1:
//   A viable function F1 is defined to be a better function than another
//   viable function F2 if for all arguments i, ICSi(F1) is not a worse
//   conversion sequence than ICSi(F2), and then...
bool HasWorseConversion = false;
for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
  switch (CompareImplicitConversionSequences(S, Loc,
                                             Cand1.Conversions[ArgIdx],
                                             Cand2.Conversions[ArgIdx])) {
  case ImplicitConversionSequence::Better:
    // Cand1 has a better conversion sequence.
    HasBetterConversion = true;
    break;

  case ImplicitConversionSequence::Worse:
    if (Cand1.Function && Cand2.Function &&
        Cand1.isReversed() != Cand2.isReversed() &&
        haveSameParameterTypes(S.Context, Cand1.Function, Cand2.Function,
                               NumArgs)) {
      // Work around large-scale breakage caused by considering reversed
      // forms of operator== in C++20:
      //
      // When comparing a function against a reversed function with the same
      // parameter types, if we have a better conversion for one argument and
      // a worse conversion for the other, the implicit conversion sequences
      // are treated as being equally good.
      //
      // This prevents a comparison function from being considered ambiguous
      // with a reversed form that is written in the same way.
      //
      // We diagnose this as an extension from CreateOverloadedBinOp.
      HasWorseConversion = true;
      break;
    }

    // Cand1 can't be better than Cand2.
    return false;

  case ImplicitConversionSequence::Indistinguishable:
    // Do nothing.
    break;
  }
}

//    -- for some argument j, ICSj(F1) is a better conversion sequence than
//       ICSj(F2), or, if not that,
if (HasBetterConversion && !HasWorseConversion)
  return true;

//   -- the context is an initialization by user-defined conversion
//      (see 8.5, 13.3.1.5) and the standard conversion sequence
//      from the return type of F1 to the destination type (i.e.,
//      the type of the entity being initialized) is a better
//      conversion sequence than the standard conversion sequence
//      from the return type of F2 to the destination type.
if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion &&
    Cand1.Function && Cand2.Function &&
    isa<CXXConversionDecl>(Cand1.Function) &&
    isa<CXXConversionDecl>(Cand2.Function)) {
  // First check whether we prefer one of the conversion functions over the
  // other. This only distinguishes the results in non-standard, extension
  // cases such as the conversion from a lambda closure type to a function
  // pointer or block.
  ImplicitConversionSequence::CompareKind Result =
      compareConversionFunctions(S, Cand1.Function, Cand2.Function);
  if (Result == ImplicitConversionSequence::Indistinguishable)
    Result = CompareStandardConversionSequences(S, Loc,
                                                Cand1.FinalConversion,
                                                Cand2.FinalConversion);

  if (Result != ImplicitConversionSequence::Indistinguishable)
    return Result == ImplicitConversionSequence::Better;

  // FIXME: Compare kind of reference binding if conversion functions
  // convert to a reference type used in direct reference binding, per
  // C++14 [over.match.best]p1 section 2 bullet 3.
}

// FIXME: Work around a defect in the C++17 guaranteed copy elision wording,
// as combined with the resolution to CWG issue 243.
//
// When the context is initialization by constructor ([over.match.ctor] or
// either phase of [over.match.list]), a constructor is preferred over
// a conversion function.
if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 &&
    Cand1.Function && Cand2.Function &&
    isa<CXXConstructorDecl>(Cand1.Function) !=
        isa<CXXConstructorDecl>(Cand2.Function))
  return isa<CXXConstructorDecl>(Cand1.Function);

//    -- F1 is a non-template function and F2 is a function template
//       specialization, or, if not that,
bool Cand1IsSpecialization = Cand1.Function &&
                             Cand1.Function->getPrimaryTemplate();
bool Cand2IsSpecialization = Cand2.Function &&
                             Cand2.Function->getPrimaryTemplate();
if (Cand1IsSpecialization != Cand2IsSpecialization)
  return Cand2IsSpecialization;

//   -- F1 and F2 are function template specializations, and the function
//      template for F1 is more specialized than the template for F2
//      according to the partial ordering rules described in 14.5.5.2, or,
//      if not that,
if (Cand1IsSpecialization && Cand2IsSpecialization) {
  if (FunctionTemplateDecl *BetterTemplate = S.getMoreSpecializedTemplate(
          Cand1.Function->getPrimaryTemplate(),
          Cand2.Function->getPrimaryTemplate(), Loc,
          isa<CXXConversionDecl>(Cand1.Function) ? TPOC_Conversion
                                                 : TPOC_Call,
          Cand1.ExplicitCallArguments, Cand2.ExplicitCallArguments,
          Cand1.isReversed() ^ Cand2.isReversed()))
    return BetterTemplate == Cand1.Function->getPrimaryTemplate();
}

//   -— F1 and F2 are non-template functions with the same
//      parameter-type-lists, and F1 is more constrained than F2 [...],
if (Cand1.Function && Cand2.Function && !Cand1IsSpecialization &&
    !Cand2IsSpecialization && Cand1.Function->hasPrototype() &&
    Cand2.Function->hasPrototype()) {
  auto *PT1 = cast<FunctionProtoType>(Cand1.Function->getFunctionType());
  auto *PT2 = cast<FunctionProtoType>(Cand2.Function->getFunctionType());
  if (PT1->getNumParams() == PT2->getNumParams() &&
      PT1->isVariadic() == PT2->isVariadic() &&
      S.FunctionParamTypesAreEqual(PT1, PT2)) {
    Expr *RC1 = Cand1.Function->getTrailingRequiresClause();
    Expr *RC2 = Cand2.Function->getTrailingRequiresClause();
    if (RC1 && RC2) {
      bool AtLeastAsConstrained1, AtLeastAsConstrained2;
      if (S.IsAtLeastAsConstrained(Cand1.Function, {RC1}, Cand2.Function,
                                   {RC2}, AtLeastAsConstrained1) ||
          S.IsAtLeastAsConstrained(Cand2.Function, {RC2}, Cand1.Function,
                                   {RC1}, AtLeastAsConstrained2))
        return false;
      if (AtLeastAsConstrained1 != AtLeastAsConstrained2)
        return AtLeastAsConstrained1;
    } else if (RC1 || RC2) {
      return RC1 != nullptr;
    }
  }
}

//   -- F1 is a constructor for a class D, F2 is a constructor for a base
//      class B of D, and for all arguments the corresponding parameters of
//      F1 and F2 have the same type.
// FIXME: Implement the "all parameters have the same type" check.
bool Cand1IsInherited =
    dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
bool Cand2IsInherited =
    dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
if (Cand1IsInherited != Cand2IsInherited)
  return Cand2IsInherited;
else if (Cand1IsInherited) {
  assert(Cand2IsInherited)((void)0);
  auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
  auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
  if (Cand1Class->isDerivedFrom(Cand2Class))
    return true;
  if (Cand2Class->isDerivedFrom(Cand1Class))
    return false;
  // Inherited from sibling base classes: still ambiguous.
}

//   -- F2 is a rewritten candidate (12.4.1.2) and F1 is not
//   -- F1 and F2 are rewritten candidates, and F2 is a synthesized candidate
//      with reversed order of parameters and F1 is not
//
// We rank reversed + different operator as worse than just reversed, but
// that comparison can never happen, because we only consider reversing for
// the maximally-rewritten operator (== or <=>).
if (Cand1.RewriteKind != Cand2.RewriteKind)
  return Cand1.RewriteKind < Cand2.RewriteKind;

// Check C++17 tie-breakers for deduction guides.
{
  auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function);
  auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function);
  if (Guide1 && Guide2) {
    //  -- F1 is generated from a deduction-guide and F2 is not
    if (Guide1->isImplicit() != Guide2->isImplicit())
      return Guide2->isImplicit();

    //  -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not
    if (Guide1->isCopyDeductionCandidate())
      return true;
  }
}

// Check for enable_if value-based overload resolution.
if (Cand1.Function && Cand2.Function) {
  Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function);
  if (Cmp != Comparison::Equal)
    return Cmp == Comparison::Better;
}

bool HasPS1 = Cand1.Function != nullptr &&
              functionHasPassObjectSizeParams(Cand1.Function);
bool HasPS2 = Cand2.Function != nullptr &&
              functionHasPassObjectSizeParams(Cand2.Function);
if (HasPS1 != HasPS2 && HasPS1)
  return true;

auto MV = isBetterMultiversionCandidate(Cand1, Cand2);
if (MV == Comparison::Better)
  return true;
if (MV == Comparison::Worse)
  return false;

// If other rules cannot determine which is better, CUDA preference is used
// to determine which is better.
if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
  FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
  return S.IdentifyCUDAPreference(Caller, Cand1.Function) >
         S.IdentifyCUDAPreference(Caller, Cand2.Function);
}

// General member function overloading is handled above, so this only handles
// constructors with address spaces.
// This only handles address spaces since C++ has no other
// qualifier that can be used with constructors.
const auto *CD1 = dyn_cast_or_null<CXXConstructorDecl>(Cand1.Function);
const auto *CD2 = dyn_cast_or_null<CXXConstructorDecl>(Cand2.Function);
if (CD1 && CD2) {
  LangAS AS1 = CD1->getMethodQualifiers().getAddressSpace();
  LangAS AS2 = CD2->getMethodQualifiers().getAddressSpace();
  if (AS1 != AS2) {
    if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
      return true;
    if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
      return false;
  }
}

return false;
9888}

9890/// Determine whether two declarations are "equivalent" for the purposes of
9891/// name lookup and overload resolution. This applies when the same internal/no
9892/// linkage entity is defined by two modules (probably by textually including
9893/// the same header). In such a case, we don't consider the declarations to
9894/// declare the same entity, but we also don't want lookups with both
9895/// declarations visible to be ambiguous in some cases (this happens when using
9896/// a modularized libstdc++).
9897bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
                                                const NamedDecl *B) {
auto *VA = dyn_cast_or_null<ValueDecl>(A);
auto *VB = dyn_cast_or_null<ValueDecl>(B);
if (!VA || !VB)
  return false;

// The declarations must be declaring the same name as an internal linkage
// entity in different modules.
if (!VA->getDeclContext()->getRedeclContext()->Equals(
        VB->getDeclContext()->getRedeclContext()) ||
    getOwningModule(VA) == getOwningModule(VB) ||
    VA->isExternallyVisible() || VB->isExternallyVisible())
  return false;

// Check that the declarations appear to be equivalent.
//
// FIXME: Checking the type isn't really enough to resolve the ambiguity.
// For constants and functions, we should check the initializer or body is
// the same. For non-constant variables, we shouldn't allow it at all.
if (Context.hasSameType(VA->getType(), VB->getType()))
  return true;

// Enum constants within unnamed enumerations will have different types, but
// may still be similar enough to be interchangeable for our purposes.
if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) {
  if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) {
    // Only handle anonymous enums. If the enumerations were named and
    // equivalent, they would have been merged to the same type.
    auto *EnumA = cast<EnumDecl>(EA->getDeclContext());
    auto *EnumB = cast<EnumDecl>(EB->getDeclContext());
    if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() ||
        !Context.hasSameType(EnumA->getIntegerType(),
                             EnumB->getIntegerType()))
      return false;
    // Allow this only if the value is the same for both enumerators.
    return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal());
  }
}

// Nothing else is sufficiently similar.
return false;
9939}

9941void Sema::diagnoseEquivalentInternalLinkageDeclarations(
  SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
assert(D && "Unknown declaration")((void)0);
Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;

Module *M = getOwningModule(D);
32
←
Passing null pointer value via 1st parameter 'Entity'→
33
←
Calling 'Sema::getOwningModule'→
Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
    << !M << (M ? M->getFullModuleName() : "");

for (auto *E : Equiv) {
  Module *M = getOwningModule(E);
  Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
      << !M << (M ? M->getFullModuleName() : "");
}
9955}

9957/// Computes the best viable function (C++ 13.3.3)
9958/// within an overload candidate set.
9959///
9960/// \param Loc The location of the function name (or operator symbol) for
9961/// which overload resolution occurs.
9962///
9963/// \param Best If overload resolution was successful or found a deleted
9964/// function, \p Best points to the candidate function found.
9965///
9966/// \returns The result of overload resolution.
9967OverloadingResult
9968OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
                                       iterator &Best) {
llvm::SmallVector<OverloadCandidate *, 16> Candidates;
std::transform(begin(), end(), std::back_inserter(Candidates),
               [](OverloadCandidate &Cand) { return &Cand; });

// [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but
// are accepted by both clang and NVCC. However, during a particular
// compilation mode only one call variant is viable. We need to
// exclude non-viable overload candidates from consideration based
// only on their host/device attributes. Specifically, if one
// candidate call is WrongSide and the other is SameSide, we ignore
// the WrongSide candidate.
// We only need to remove wrong-sided candidates here if
// -fgpu-exclude-wrong-side-overloads is off. When
// -fgpu-exclude-wrong-side-overloads is on, all candidates are compared
// uniformly in isBetterOverloadCandidate.
if (S.getLangOpts().CUDA && !S.getLangOpts().GPUExcludeWrongSideOverloads) {
16
←
Assuming field 'CUDA' is 0→
  const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
  bool ContainsSameSideCandidate =
      llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
        // Check viable function only.
        return Cand->Viable && Cand->Function &&
               S.IdentifyCUDAPreference(Caller, Cand->Function) ==
                   Sema::CFP_SameSide;
      });
  if (ContainsSameSideCandidate) {
    auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
      // Check viable function only to avoid unnecessary data copying/moving.
      return Cand->Viable && Cand->Function &&
             S.IdentifyCUDAPreference(Caller, Cand->Function) ==
                 Sema::CFP_WrongSide;
    };
    llvm::erase_if(Candidates, IsWrongSideCandidate);
  }
}

// Find the best viable function.
Best = end();
for (auto *Cand : Candidates) {
17
←
Assuming '__begin1' is equal to '__end1'→
  Cand->Best = false;
  if (Cand->Viable)
    if (Best == end() ||
        isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind))
      Best = Cand;
}

// If we didn't find any viable functions, abort.
if (Best == end())
18
←
Assuming the condition is false→
19
←
Taking false branch→
  return OR_No_Viable_Function;

llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;

llvm::SmallVector<OverloadCandidate*, 4> PendingBest;
PendingBest.push_back(&*Best);
20
←
Value assigned to field 'Function'→
Best->Best = true;

// Make sure that this function is better than every other viable
// function. If not, we have an ambiguity.
while (!PendingBest.empty()) {
21
←
Loop condition is false. Execution continues on line 10045→
  auto *Curr = PendingBest.pop_back_val();
  for (auto *Cand : Candidates) {
    if (Cand->Viable && !Cand->Best &&
        !isBetterOverloadCandidate(S, *Curr, *Cand, Loc, Kind)) {
      PendingBest.push_back(Cand);
      Cand->Best = true;

      if (S.isEquivalentInternalLinkageDeclaration(Cand->Function,
                                                   Curr->Function))
        EquivalentCands.push_back(Cand->Function);
      else
        Best = end();
    }
  }
}

// If we found more than one best candidate, this is ambiguous.
if (Best == end())
22
←
Assuming the condition is false→
23
←
Taking false branch→
  return OR_Ambiguous;

// Best is the best viable function.
if (Best->Function && Best->Function->isDeleted())
24
←
Assuming field 'Function' is null→
  return OR_Deleted;

if (!EquivalentCands.empty())
25
←
Calling 'SmallVectorBase::empty'→
28
←
Returning from 'SmallVectorBase::empty'→
29
←
Taking true branch→
  S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
30
←
Passing null pointer value via 2nd parameter 'D'→
31
←
Calling 'Sema::diagnoseEquivalentInternalLinkageDeclarations'→
                                                  EquivalentCands);

return OR_Success;
10057}

10059namespace {

10061enum OverloadCandidateKind {
oc_function,
oc_method,
oc_reversed_binary_operator,
oc_constructor,
oc_implicit_default_constructor,
oc_implicit_copy_constructor,
oc_implicit_move_constructor,
oc_implicit_copy_assignment,
oc_implicit_move_assignment,
oc_implicit_equality_comparison,
oc_inherited_constructor
10073};

10075enum OverloadCandidateSelect {
ocs_non_template,
ocs_template,
ocs_described_template,
10079};

10081static std::pair<OverloadCandidateKind, OverloadCandidateSelect>
10082ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn,
                        OverloadCandidateRewriteKind CRK,
                        std::string &Description) {

bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl();
if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) {
  isTemplate = true;
  Description = S.getTemplateArgumentBindingsText(
      FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs());
}

OverloadCandidateSelect Select = [&]() {
  if (!Description.empty())
    return ocs_described_template;
  return isTemplate ? ocs_template : ocs_non_template;
}();

OverloadCandidateKind Kind = [&]() {
  if (Fn->isImplicit() && Fn->getOverloadedOperator() == OO_EqualEqual)
    return oc_implicit_equality_comparison;

  if (CRK & CRK_Reversed)
    return oc_reversed_binary_operator;

  if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) {
    if (!Ctor->isImplicit()) {
      if (isa<ConstructorUsingShadowDecl>(Found))
        return oc_inherited_constructor;
      else
        return oc_constructor;
    }

    if (Ctor->isDefaultConstructor())
      return oc_implicit_default_constructor;

    if (Ctor->isMoveConstructor())
      return oc_implicit_move_constructor;

    assert(Ctor->isCopyConstructor() &&((void)0)
           "unexpected sort of implicit constructor")((void)0);
    return oc_implicit_copy_constructor;
  }

  if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) {
    // This actually gets spelled 'candidate function' for now, but
    // it doesn't hurt to split it out.
    if (!Meth->isImplicit())
      return oc_method;

    if (Meth->isMoveAssignmentOperator())
      return oc_implicit_move_assignment;

    if (Meth->isCopyAssignmentOperator())
      return oc_implicit_copy_assignment;

    assert(isa<CXXConversionDecl>(Meth) && "expected conversion")((void)0);
    return oc_method;
  }

  return oc_function;
}();

return std::make_pair(Kind, Select);
10145}

10147void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) {
// FIXME: It'd be nice to only emit a note once per using-decl per overload
// set.
if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl))
  S.Diag(FoundDecl->getLocation(),
         diag::note_ovl_candidate_inherited_constructor)
    << Shadow->getNominatedBaseClass();
10154}

10156} // end anonymous namespace

10158static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
                                  const FunctionDecl *FD) {
for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
  bool AlwaysTrue;
  if (EnableIf->getCond()->isValueDependent() ||
      !EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
    return false;
  if (!AlwaysTrue)
    return false;
}
return true;
10169}

10171/// Returns true if we can take the address of the function.
10172///
10173/// \param Complain - If true, we'll emit a diagnostic
10174/// \param InOverloadResolution - For the purposes of emitting a diagnostic, are
10175///   we in overload resolution?
10176/// \param Loc - The location of the statement we're complaining about. Ignored
10177///   if we're not complaining, or if we're in overload resolution.
10178static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD,
                                            bool Complain,
                                            bool InOverloadResolution,
                                            SourceLocation Loc) {
if (!isFunctionAlwaysEnabled(S.Context, FD)) {
  if (Complain) {
    if (InOverloadResolution)
      S.Diag(FD->getBeginLoc(),
             diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr);
    else
      S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD;
  }
  return false;
}

if (FD->getTrailingRequiresClause()) {
  ConstraintSatisfaction Satisfaction;
  if (S.CheckFunctionConstraints(FD, Satisfaction, Loc))
    return false;
  if (!Satisfaction.IsSatisfied) {
    if (Complain) {
      if (InOverloadResolution)
        S.Diag(FD->getBeginLoc(),
               diag::note_ovl_candidate_unsatisfied_constraints);
      else
        S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied)
            << FD;
      S.DiagnoseUnsatisfiedConstraint(Satisfaction);
    }
    return false;
  }
}

auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) {
  return P->hasAttr<PassObjectSizeAttr>();
});
if (I == FD->param_end())
  return true;

if (Complain) {
  // Add one to ParamNo because it's user-facing
  unsigned ParamNo = std::distance(FD->param_begin(), I) + 1;
  if (InOverloadResolution)
    S.Diag(FD->getLocation(),
           diag::note_ovl_candidate_has_pass_object_size_params)
        << ParamNo;
  else
    S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params)
        << FD << ParamNo;
}
return false;
10229}

10231static bool checkAddressOfCandidateIsAvailable(Sema &S,
                                             const FunctionDecl *FD) {
return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true,
                                         /*InOverloadResolution=*/true,
                                         /*Loc=*/SourceLocation());
10236}

10238bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
                                           bool Complain,
                                           SourceLocation Loc) {
return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain,
                                           /*InOverloadResolution=*/false,
                                           Loc);
10244}

10246// Don't print candidates other than the one that matches the calling
10247// convention of the call operator, since that is guaranteed to exist.
10248static bool shouldSkipNotingLambdaConversionDecl(FunctionDecl *Fn) {
const auto *ConvD = dyn_cast<CXXConversionDecl>(Fn);

if (!ConvD)
  return false;
const auto *RD = cast<CXXRecordDecl>(Fn->getParent());
if (!RD->isLambda())
  return false;

CXXMethodDecl *CallOp = RD->getLambdaCallOperator();
CallingConv CallOpCC =
    CallOp->getType()->castAs<FunctionType>()->getCallConv();
QualType ConvRTy = ConvD->getType()->castAs<FunctionType>()->getReturnType();
CallingConv ConvToCC =
    ConvRTy->getPointeeType()->castAs<FunctionType>()->getCallConv();

return ConvToCC != CallOpCC;
10265}

10267// Notes the location of an overload candidate.
10268void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
                               OverloadCandidateRewriteKind RewriteKind,
                               QualType DestType, bool TakingAddress) {
if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn))
  return;
if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() &&
    !Fn->getAttr<TargetAttr>()->isDefaultVersion())
  return;
if (shouldSkipNotingLambdaConversionDecl(Fn))
  return;

std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair =
    ClassifyOverloadCandidate(*this, Found, Fn, RewriteKind, FnDesc);
PartialDiagnostic PD = PDiag(diag::note_ovl_candidate)
                       << (unsigned)KSPair.first << (unsigned)KSPair.second
                       << Fn << FnDesc;

HandleFunctionTypeMismatch(PD, Fn->getType(), DestType);
Diag(Fn->getLocation(), PD);
MaybeEmitInheritedConstructorNote(*this, Found);
10289}

10291static void
10292MaybeDiagnoseAmbiguousConstraints(Sema &S, ArrayRef<OverloadCandidate> Cands) {
// Perhaps the ambiguity was caused by two atomic constraints that are
// 'identical' but not equivalent:
//
// void foo() requires (sizeof(T) > 4) { } // #1
// void foo() requires (sizeof(T) > 4) && T::value { } // #2
//
// The 'sizeof(T) > 4' constraints are seemingly equivalent and should cause
// #2 to subsume #1, but these constraint are not considered equivalent
// according to the subsumption rules because they are not the same
// source-level construct. This behavior is quite confusing and we should try
// to help the user figure out what happened.

SmallVector<const Expr *, 3> FirstAC, SecondAC;
FunctionDecl *FirstCand = nullptr, *SecondCand = nullptr;
for (auto I = Cands.begin(), E = Cands.end(); I != E; ++I) {
  if (!I->Function)
    continue;
  SmallVector<const Expr *, 3> AC;
  if (auto *Template = I->Function->getPrimaryTemplate())
    Template->getAssociatedConstraints(AC);
  else
    I->Function->getAssociatedConstraints(AC);
  if (AC.empty())
    continue;
  if (FirstCand == nullptr) {
    FirstCand = I->Function;
    FirstAC = AC;
  } else if (SecondCand == nullptr) {
    SecondCand = I->Function;
    SecondAC = AC;
  } else {
    // We have more than one pair of constrained functions - this check is
    // expensive and we'd rather not try to diagnose it.
    return;
  }
}
if (!SecondCand)
  return;
// The diagnostic can only happen if there are associated constraints on
// both sides (there needs to be some identical atomic constraint).
if (S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(FirstCand, FirstAC,
                                                    SecondCand, SecondAC))
  // Just show the user one diagnostic, they'll probably figure it out
  // from here.
  return;
10338}

10340// Notes the location of all overload candidates designated through
10341// OverloadedExpr
10342void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType,
                                   bool TakingAddress) {
assert(OverloadedExpr->getType() == Context.OverloadTy)((void)0);

OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr);
OverloadExpr *OvlExpr = Ovl.Expression;

for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
                          IEnd = OvlExpr->decls_end();
     I != IEnd; ++I) {
  if (FunctionTemplateDecl *FunTmpl =
              dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) {
    NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), CRK_None, DestType,
                          TakingAddress);
  } else if (FunctionDecl *Fun
                    = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) {
    NoteOverloadCandidate(*I, Fun, CRK_None, DestType, TakingAddress);
  }
}
10361}

10363/// Diagnoses an ambiguous conversion.  The partial diagnostic is the
10364/// "lead" diagnostic; it will be given two arguments, the source and
10365/// target types of the conversion.
10366void ImplicitConversionSequence::DiagnoseAmbiguousConversion(
                               Sema &S,
                               SourceLocation CaretLoc,
                               const PartialDiagnostic &PDiag) const {
S.Diag(CaretLoc, PDiag)
  << Ambiguous.getFromType() << Ambiguous.getToType();
unsigned CandsShown = 0;
AmbiguousConversionSequence::const_iterator I, E;
for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) {
  if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow())
    break;
  ++CandsShown;
  S.NoteOverloadCandidate(I->first, I->second);
}
S.Diags.overloadCandidatesShown(CandsShown);
if (I != E)
  S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I);
10383}

10385static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
                                unsigned I, bool TakingCandidateAddress) {
const ImplicitConversionSequence &Conv = Cand->Conversions[I];
assert(Conv.isBad())((void)0);
assert(Cand->Function && "for now, candidate must be a function")((void)0);
FunctionDecl *Fn = Cand->Function;

// There's a conversion slot for the object argument if this is a
// non-constructor method.  Note that 'I' corresponds the
// conversion-slot index.
bool isObjectArgument = false;
if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) {
  if (I == 0)
    isObjectArgument = true;
  else
    I--;
}

std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
    ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(),
                              FnDesc);

Expr *FromExpr = Conv.Bad.FromExpr;
QualType FromTy = Conv.Bad.getFromType();
QualType ToTy = Conv.Bad.getToType();

if (FromTy == S.Context.OverloadTy) {
  assert(FromExpr && "overload set argument came from implicit argument?")((void)0);
  Expr *E = FromExpr->IgnoreParens();
  if (isa<UnaryOperator>(E))
    E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
  DeclarationName Name = cast<OverloadExpr>(E)->getName();

  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy
      << Name << I + 1;
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

// Do some hand-waving analysis to see if the non-viability is due
// to a qualifier mismatch.
CanQualType CFromTy = S.Context.getCanonicalType(FromTy);
CanQualType CToTy = S.Context.getCanonicalType(ToTy);
if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>())
  CToTy = RT->getPointeeType();
else {
  // TODO: detect and diagnose the full richness of const mismatches.
  if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>())
    if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) {
      CFromTy = FromPT->getPointeeType();
      CToTy = ToPT->getPointeeType();
    }
}

if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() &&
    !CToTy.isAtLeastAsQualifiedAs(CFromTy)) {
  Qualifiers FromQs = CFromTy.getQualifiers();
  Qualifiers ToQs = CToTy.getQualifiers();

  if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) {
    if (isObjectArgument)
      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace_this)
          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
          << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
          << FromQs.getAddressSpace() << ToQs.getAddressSpace();
    else
      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace)
          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
          << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
          << FromQs.getAddressSpace() << ToQs.getAddressSpace()
          << ToTy->isReferenceType() << I + 1;
    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
    return;
  }

  if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
        << FromQs.getObjCLifetime() << ToQs.getObjCLifetime()
        << (unsigned)isObjectArgument << I + 1;
    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
    return;
  }

  if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
        << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
        << (unsigned)isObjectArgument << I + 1;
    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
    return;
  }

  if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
        << FromQs.hasUnaligned() << I + 1;
    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
    return;
  }

  unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
  assert(CVR && "expected qualifiers mismatch")((void)0);

  if (isObjectArgument) {
    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
        << (CVR - 1);
  } else {
    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
        << (CVR - 1) << I + 1;
  }
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

if (Conv.Bad.Kind == BadConversionSequence::lvalue_ref_to_rvalue ||
    Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue) {
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_value_category)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (unsigned)isObjectArgument << I + 1
      << (Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue)
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange());
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

// Special diagnostic for failure to convert an initializer list, since
// telling the user that it has type void is not useful.
if (FromExpr && isa<InitListExpr>(FromExpr)) {
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
      << ToTy << (unsigned)isObjectArgument << I + 1;
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

// Diagnose references or pointers to incomplete types differently,
// since it's far from impossible that the incompleteness triggered
// the failure.
QualType TempFromTy = FromTy.getNonReferenceType();
if (const PointerType *PTy = TempFromTy->getAs<PointerType>())
  TempFromTy = PTy->getPointeeType();
if (TempFromTy->isIncompleteType()) {
  // Emit the generic diagnostic and, optionally, add the hints to it.
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
      << ToTy << (unsigned)isObjectArgument << I + 1
      << (unsigned)(Cand->Fix.Kind);

  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

// Diagnose base -> derived pointer conversions.
unsigned BaseToDerivedConversion = 0;
if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) {
  if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) {
    if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
                                             FromPtrTy->getPointeeType()) &&
        !FromPtrTy->getPointeeType()->isIncompleteType() &&
        !ToPtrTy->getPointeeType()->isIncompleteType() &&
        S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(),
                        FromPtrTy->getPointeeType()))
      BaseToDerivedConversion = 1;
  }
} else if (const ObjCObjectPointerType *FromPtrTy
                                  = FromTy->getAs<ObjCObjectPointerType>()) {
  if (const ObjCObjectPointerType *ToPtrTy
                                      = ToTy->getAs<ObjCObjectPointerType>())
    if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl())
      if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl())
        if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
                                              FromPtrTy->getPointeeType()) &&
            FromIface->isSuperClassOf(ToIface))
          BaseToDerivedConversion = 2;
} else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) {
  if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) &&
      !FromTy->isIncompleteType() &&
      !ToRefTy->getPointeeType()->isIncompleteType() &&
      S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) {
    BaseToDerivedConversion = 3;
  }
}

if (BaseToDerivedConversion) {
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
      << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1;
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

if (isa<ObjCObjectPointerType>(CFromTy) &&
    isa<PointerType>(CToTy)) {
    Qualifiers FromQs = CFromTy.getQualifiers();
    Qualifiers ToQs = CToTy.getQualifiers();
    if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv)
          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
          << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
          << FromTy << ToTy << (unsigned)isObjectArgument << I + 1;
      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
      return;
    }
}

if (TakingCandidateAddress &&
    !checkAddressOfCandidateIsAvailable(S, Cand->Function))
  return;

// Emit the generic diagnostic and, optionally, add the hints to it.
PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv);
FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
      << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
      << ToTy << (unsigned)isObjectArgument << I + 1
      << (unsigned)(Cand->Fix.Kind);

// If we can fix the conversion, suggest the FixIts.
for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(),
     HE = Cand->Fix.Hints.end(); HI != HE; ++HI)
  FDiag << *HI;
S.Diag(Fn->getLocation(), FDiag);

MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10622}

10624/// Additional arity mismatch diagnosis specific to a function overload
10625/// candidates. This is not covered by the more general DiagnoseArityMismatch()
10626/// over a candidate in any candidate set.
10627static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand,
                             unsigned NumArgs) {
FunctionDecl *Fn = Cand->Function;
unsigned MinParams = Fn->getMinRequiredArguments();

// With invalid overloaded operators, it's possible that we think we
// have an arity mismatch when in fact it looks like we have the
// right number of arguments, because only overloaded operators have
// the weird behavior of overloading member and non-member functions.
// Just don't report anything.
if (Fn->isInvalidDecl() &&
    Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
  return true;

if (NumArgs < MinParams) {
  assert((Cand->FailureKind == ovl_fail_too_few_arguments) ||((void)0)
         (Cand->FailureKind == ovl_fail_bad_deduction &&((void)0)
          Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments))((void)0);
} else {
  assert((Cand->FailureKind == ovl_fail_too_many_arguments) ||((void)0)
         (Cand->FailureKind == ovl_fail_bad_deduction &&((void)0)
          Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments))((void)0);
}

return false;
10652}

10654/// General arity mismatch diagnosis over a candidate in a candidate set.
10655static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D,
                                unsigned NumFormalArgs) {
assert(isa<FunctionDecl>(D) &&((void)0)
    "The templated declaration should at least be a function"((void)0)
    " when diagnosing bad template argument deduction due to too many"((void)0)
    " or too few arguments")((void)0);

FunctionDecl *Fn = cast<FunctionDecl>(D);

// TODO: treat calls to a missing default constructor as a special case
const auto *FnTy = Fn->getType()->castAs<FunctionProtoType>();
unsigned MinParams = Fn->getMinRequiredArguments();

// at least / at most / exactly
unsigned mode, modeCount;
if (NumFormalArgs < MinParams) {
  if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() ||
      FnTy->isTemplateVariadic())
    mode = 0; // "at least"
  else
    mode = 2; // "exactly"
  modeCount = MinParams;
} else {
  if (MinParams != FnTy->getNumParams())
    mode = 1; // "at most"
  else
    mode = 2; // "exactly"
  modeCount = FnTy->getNumParams();
}

std::string Description;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
    ClassifyOverloadCandidate(S, Found, Fn, CRK_None, Description);

if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName())
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
      << Description << mode << Fn->getParamDecl(0) << NumFormalArgs;
else
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity)
      << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
      << Description << mode << modeCount << NumFormalArgs;

MaybeEmitInheritedConstructorNote(S, Found);
10699}

10701/// Arity mismatch diagnosis specific to a function overload candidate.
10702static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
                                unsigned NumFormalArgs) {
if (!CheckArityMismatch(S, Cand, NumFormalArgs))
  DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs);
10706}

10708static TemplateDecl *getDescribedTemplate(Decl *Templated) {
if (TemplateDecl *TD = Templated->getDescribedTemplate())
  return TD;
llvm_unreachable("Unsupported: Getting the described template declaration"__builtin_unreachable()
                 " for bad deduction diagnosis")__builtin_unreachable();
10713}

10715/// Diagnose a failed template-argument deduction.
10716static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated,
                               DeductionFailureInfo &DeductionFailure,
                               unsigned NumArgs,
                               bool TakingCandidateAddress) {
TemplateParameter Param = DeductionFailure.getTemplateParameter();
NamedDecl *ParamD;
(ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) ||
(ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) ||
(ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>());
switch (DeductionFailure.Result) {
case Sema::TDK_Success:
  llvm_unreachable("TDK_success while diagnosing bad deduction")__builtin_unreachable();

case Sema::TDK_Incomplete: {
  assert(ParamD && "no parameter found for incomplete deduction result")((void)0);
  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_incomplete_deduction)
      << ParamD->getDeclName();
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
}

case Sema::TDK_IncompletePack: {
  assert(ParamD && "no parameter found for incomplete deduction result")((void)0);
  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_incomplete_deduction_pack)
      << ParamD->getDeclName()
      << (DeductionFailure.getFirstArg()->pack_size() + 1)
      << *DeductionFailure.getFirstArg();
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
}

case Sema::TDK_Underqualified: {
  assert(ParamD && "no parameter found for bad qualifiers deduction result")((void)0);
  TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD);

  QualType Param = DeductionFailure.getFirstArg()->getAsType();

  // Param will have been canonicalized, but it should just be a
  // qualified version of ParamD, so move the qualifiers to that.
  QualifierCollector Qs;
  Qs.strip(Param);
  QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl());
  assert(S.Context.hasSameType(Param, NonCanonParam))((void)0);

  // Arg has also been canonicalized, but there's nothing we can do
  // about that.  It also doesn't matter as much, because it won't
  // have any template parameters in it (because deduction isn't
  // done on dependent types).
  QualType Arg = DeductionFailure.getSecondArg()->getAsType();

  S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified)
      << ParamD->getDeclName() << Arg << NonCanonParam;
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
}

case Sema::TDK_Inconsistent: {
  assert(ParamD && "no parameter found for inconsistent deduction result")((void)0);
  int which = 0;
  if (isa<TemplateTypeParmDecl>(ParamD))
    which = 0;
  else if (isa<NonTypeTemplateParmDecl>(ParamD)) {
    // Deduction might have failed because we deduced arguments of two
    // different types for a non-type template parameter.
    // FIXME: Use a different TDK value for this.
    QualType T1 =
        DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType();
    QualType T2 =
        DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType();
    if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) {
      S.Diag(Templated->getLocation(),
             diag::note_ovl_candidate_inconsistent_deduction_types)
        << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1
        << *DeductionFailure.getSecondArg() << T2;
      MaybeEmitInheritedConstructorNote(S, Found);
      return;
    }

    which = 1;
  } else {
    which = 2;
  }

  // Tweak the diagnostic if the problem is that we deduced packs of
  // different arities. We'll print the actual packs anyway in case that
  // includes additional useful information.
  if (DeductionFailure.getFirstArg()->getKind() == TemplateArgument::Pack &&
      DeductionFailure.getSecondArg()->getKind() == TemplateArgument::Pack &&
      DeductionFailure.getFirstArg()->pack_size() !=
          DeductionFailure.getSecondArg()->pack_size()) {
    which = 3;
  }

  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_inconsistent_deduction)
      << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg()
      << *DeductionFailure.getSecondArg();
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
}

case Sema::TDK_InvalidExplicitArguments:
  assert(ParamD && "no parameter found for invalid explicit arguments")((void)0);
  if (ParamD->getDeclName())
    S.Diag(Templated->getLocation(),
           diag::note_ovl_candidate_explicit_arg_mismatch_named)
        << ParamD->getDeclName();
  else {
    int index = 0;
    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD))
      index = TTP->getIndex();
    else if (NonTypeTemplateParmDecl *NTTP
                                = dyn_cast<NonTypeTemplateParmDecl>(ParamD))
      index = NTTP->getIndex();
    else
      index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex();
    S.Diag(Templated->getLocation(),
           diag::note_ovl_candidate_explicit_arg_mismatch_unnamed)
        << (index + 1);
  }
  MaybeEmitInheritedConstructorNote(S, Found);
  return;

case Sema::TDK_ConstraintsNotSatisfied: {
  // Format the template argument list into the argument string.
  SmallString<128> TemplateArgString;
  TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList();
  TemplateArgString = " ";
  TemplateArgString += S.getTemplateArgumentBindingsText(
      getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
  if (TemplateArgString.size() == 1)
    TemplateArgString.clear();
  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_unsatisfied_constraints)
      << TemplateArgString;

  S.DiagnoseUnsatisfiedConstraint(
      static_cast<CNSInfo*>(DeductionFailure.Data)->Satisfaction);
  return;
}
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
  DiagnoseArityMismatch(S, Found, Templated, NumArgs);
  return;

case Sema::TDK_InstantiationDepth:
  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_instantiation_depth);
  MaybeEmitInheritedConstructorNote(S, Found);
  return;

case Sema::TDK_SubstitutionFailure: {
  // Format the template argument list into the argument string.
  SmallString<128> TemplateArgString;
  if (TemplateArgumentList *Args =
          DeductionFailure.getTemplateArgumentList()) {
    TemplateArgString = " ";
    TemplateArgString += S.getTemplateArgumentBindingsText(
        getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
    if (TemplateArgString.size() == 1)
      TemplateArgString.clear();
  }

  // If this candidate was disabled by enable_if, say so.
  PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic();
  if (PDiag && PDiag->second.getDiagID() ==
        diag::err_typename_nested_not_found_enable_if) {
    // FIXME: Use the source range of the condition, and the fully-qualified
    //        name of the enable_if template. These are both present in PDiag.
    S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if)
      << "'enable_if'" << TemplateArgString;
    return;
  }

  // We found a specific requirement that disabled the enable_if.
  if (PDiag && PDiag->second.getDiagID() ==
      diag::err_typename_nested_not_found_requirement) {
    S.Diag(Templated->getLocation(),
           diag::note_ovl_candidate_disabled_by_requirement)
      << PDiag->second.getStringArg(0) << TemplateArgString;
    return;
  }

  // Format the SFINAE diagnostic into the argument string.
  // FIXME: Add a general mechanism to include a PartialDiagnostic *'s
  //        formatted message in another diagnostic.
  SmallString<128> SFINAEArgString;
  SourceRange R;
  if (PDiag) {
    SFINAEArgString = ": ";
    R = SourceRange(PDiag->first, PDiag->first);
    PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
  }

  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_substitution_failure)
      << TemplateArgString << SFINAEArgString << R;
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
}

case Sema::TDK_DeducedMismatch:
case Sema::TDK_DeducedMismatchNested: {
  // Format the template argument list into the argument string.
  SmallString<128> TemplateArgString;
  if (TemplateArgumentList *Args =
          DeductionFailure.getTemplateArgumentList()) {
    TemplateArgString = " ";
    TemplateArgString += S.getTemplateArgumentBindingsText(
        getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
    if (TemplateArgString.size() == 1)
      TemplateArgString.clear();
  }

  S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch)
      << (*DeductionFailure.getCallArgIndex() + 1)
      << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg()
      << TemplateArgString
      << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested);
  break;
}

case Sema::TDK_NonDeducedMismatch: {
  // FIXME: Provide a source location to indicate what we couldn't match.
  TemplateArgument FirstTA = *DeductionFailure.getFirstArg();
  TemplateArgument SecondTA = *DeductionFailure.getSecondArg();
  if (FirstTA.getKind() == TemplateArgument::Template &&
      SecondTA.getKind() == TemplateArgument::Template) {
    TemplateName FirstTN = FirstTA.getAsTemplate();
    TemplateName SecondTN = SecondTA.getAsTemplate();
    if (FirstTN.getKind() == TemplateName::Template &&
        SecondTN.getKind() == TemplateName::Template) {
      if (FirstTN.getAsTemplateDecl()->getName() ==
          SecondTN.getAsTemplateDecl()->getName()) {
        // FIXME: This fixes a bad diagnostic where both templates are named
        // the same.  This particular case is a bit difficult since:
        // 1) It is passed as a string to the diagnostic printer.
        // 2) The diagnostic printer only attempts to find a better
        //    name for types, not decls.
        // Ideally, this should folded into the diagnostic printer.
        S.Diag(Templated->getLocation(),
               diag::note_ovl_candidate_non_deduced_mismatch_qualified)
            << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl();
        return;
      }
    }
  }

  if (TakingCandidateAddress && isa<FunctionDecl>(Templated) &&
      !checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated)))
    return;

  // FIXME: For generic lambda parameters, check if the function is a lambda
  // call operator, and if so, emit a prettier and more informative
  // diagnostic that mentions 'auto' and lambda in addition to
  // (or instead of?) the canonical template type parameters.
  S.Diag(Templated->getLocation(),
         diag::note_ovl_candidate_non_deduced_mismatch)
      << FirstTA << SecondTA;
  return;
}
// TODO: diagnose these individually, then kill off
// note_ovl_candidate_bad_deduction, which is uselessly vague.
case Sema::TDK_MiscellaneousDeductionFailure:
  S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction);
  MaybeEmitInheritedConstructorNote(S, Found);
  return;
case Sema::TDK_CUDATargetMismatch:
  S.Diag(Templated->getLocation(),
         diag::note_cuda_ovl_candidate_target_mismatch);
  return;
}
10990}

10992/// Diagnose a failed template-argument deduction, for function calls.
10993static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand,
                               unsigned NumArgs,
                               bool TakingCandidateAddress) {
unsigned TDK = Cand->DeductionFailure.Result;
if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) {
  if (CheckArityMismatch(S, Cand, NumArgs))
    return;
}
DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern
                     Cand->DeductionFailure, NumArgs, TakingCandidateAddress);
11003}

11005/// CUDA: diagnose an invalid call across targets.
11006static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) {
FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext);
FunctionDecl *Callee = Cand->Function;

Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller),
                         CalleeTarget = S.IdentifyCUDATarget(Callee);

std::string FnDesc;
std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
    ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee,
                              Cand->getRewriteKind(), FnDesc);

S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target)
    << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
    << FnDesc /* Ignored */
    << CalleeTarget << CallerTarget;

// This could be an implicit constructor for which we could not infer the
// target due to a collsion. Diagnose that case.
CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee);
if (Meth != nullptr && Meth->isImplicit()) {
  CXXRecordDecl *ParentClass = Meth->getParent();
  Sema::CXXSpecialMember CSM;

  switch (FnKindPair.first) {
  default:
    return;
  case oc_implicit_default_constructor:
    CSM = Sema::CXXDefaultConstructor;
    break;
  case oc_implicit_copy_constructor:
    CSM = Sema::CXXCopyConstructor;
    break;
  case oc_implicit_move_constructor:
    CSM = Sema::CXXMoveConstructor;
    break;
  case oc_implicit_copy_assignment:
    CSM = Sema::CXXCopyAssignment;
    break;
  case oc_implicit_move_assignment:
    CSM = Sema::CXXMoveAssignment;
    break;
  };

  bool ConstRHS = false;
  if (Meth->getNumParams()) {
    if (const ReferenceType *RT =
            Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) {
      ConstRHS = RT->getPointeeType().isConstQualified();
    }
  }

  S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth,
                                            /* ConstRHS */ ConstRHS,
                                            /* Diagnose */ true);
}
11062}

11064static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) {
FunctionDecl *Callee = Cand->Function;
EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data);

S.Diag(Callee->getLocation(),
       diag::note_ovl_candidate_disabled_by_function_cond_attr)
    << Attr->getCond()->getSourceRange() << Attr->getMessage();
11071}

11073static void DiagnoseFailedExplicitSpec(Sema &S, OverloadCandidate *Cand) {
ExplicitSpecifier ES = ExplicitSpecifier::getFromDecl(Cand->Function);
assert(ES.isExplicit() && "not an explicit candidate")((void)0);

unsigned Kind;
switch (Cand->Function->getDeclKind()) {
case Decl::Kind::CXXConstructor:
  Kind = 0;
  break;
case Decl::Kind::CXXConversion:
  Kind = 1;
  break;
case Decl::Kind::CXXDeductionGuide:
  Kind = Cand->Function->isImplicit() ? 0 : 2;
  break;
default:
  llvm_unreachable("invalid Decl")__builtin_unreachable();
}

// Note the location of the first (in-class) declaration; a redeclaration
// (particularly an out-of-class definition) will typically lack the
// 'explicit' specifier.
// FIXME: This is probably a good thing to do for all 'candidate' notes.
FunctionDecl *First = Cand->Function->getFirstDecl();
if (FunctionDecl *Pattern = First->getTemplateInstantiationPattern())
  First = Pattern->getFirstDecl();

S.Diag(First->getLocation(),
       diag::note_ovl_candidate_explicit)
    << Kind << (ES.getExpr() ? 1 : 0)
    << (ES.getExpr() ? ES.getExpr()->getSourceRange() : SourceRange());
11104}

11106/// Generates a 'note' diagnostic for an overload candidate.  We've
11107/// already generated a primary error at the call site.
11108///
11109/// It really does need to be a single diagnostic with its caret
11110/// pointed at the candidate declaration.  Yes, this creates some
11111/// major challenges of technical writing.  Yes, this makes pointing
11112/// out problems with specific arguments quite awkward.  It's still
11113/// better than generating twenty screens of text for every failed
11114/// overload.
11115///
11116/// It would be great to be able to express per-candidate problems
11117/// more richly for those diagnostic clients that cared, but we'd
11118/// still have to be just as careful with the default diagnostics.
11119/// \param CtorDestAS Addr space of object being constructed (for ctor
11120/// candidates only).
11121static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
                                unsigned NumArgs,
                                bool TakingCandidateAddress,
                                LangAS CtorDestAS = LangAS::Default) {
FunctionDecl *Fn = Cand->Function;
if (shouldSkipNotingLambdaConversionDecl(Fn))
  return;

// Note deleted candidates, but only if they're viable.
if (Cand->Viable) {
  if (Fn->isDeleted()) {
    std::string FnDesc;
    std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
        ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
                                  Cand->getRewriteKind(), FnDesc);

    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted)
        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
        << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0);
    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
    return;
  }

  // We don't really have anything else to say about viable candidates.
  S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
  return;
}

switch (Cand->FailureKind) {
case ovl_fail_too_many_arguments:
case ovl_fail_too_few_arguments:
  return DiagnoseArityMismatch(S, Cand, NumArgs);

case ovl_fail_bad_deduction:
  return DiagnoseBadDeduction(S, Cand, NumArgs,
                              TakingCandidateAddress);

case ovl_fail_illegal_constructor: {
  S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor)
    << (Fn->getPrimaryTemplate() ? 1 : 0);
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

case ovl_fail_object_addrspace_mismatch: {
  Qualifiers QualsForPrinting;
  QualsForPrinting.setAddressSpace(CtorDestAS);
  S.Diag(Fn->getLocation(),
         diag::note_ovl_candidate_illegal_constructor_adrspace_mismatch)
      << QualsForPrinting;
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;
}

case ovl_fail_trivial_conversion:
case ovl_fail_bad_final_conversion:
case ovl_fail_final_conversion_not_exact:
  return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());

case ovl_fail_bad_conversion: {
  unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0);
  for (unsigned N = Cand->Conversions.size(); I != N; ++I)
    if (Cand->Conversions[I].isBad())
      return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress);

  // FIXME: this currently happens when we're called from SemaInit
  // when user-conversion overload fails.  Figure out how to handle
  // those conditions and diagnose them well.
  return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
}

case ovl_fail_bad_target:
  return DiagnoseBadTarget(S, Cand);

case ovl_fail_enable_if:
  return DiagnoseFailedEnableIfAttr(S, Cand);

case ovl_fail_explicit:
  return DiagnoseFailedExplicitSpec(S, Cand);

case ovl_fail_inhctor_slice:
  // It's generally not interesting to note copy/move constructors here.
  if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor())
    return;
  S.Diag(Fn->getLocation(),
         diag::note_ovl_candidate_inherited_constructor_slice)
    << (Fn->getPrimaryTemplate() ? 1 : 0)
    << Fn->getParamDecl(0)->getType()->isRValueReferenceType();
  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
  return;

case ovl_fail_addr_not_available: {
  bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function);
  (void)Available;
  assert(!Available)((void)0);
  break;
}
case ovl_non_default_multiversion_function:
  // Do nothing, these should simply be ignored.
  break;

case ovl_fail_constraints_not_satisfied: {
  std::string FnDesc;
  std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
      ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
                                Cand->getRewriteKind(), FnDesc);

  S.Diag(Fn->getLocation(),
         diag::note_ovl_candidate_constraints_not_satisfied)
      << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
      << FnDesc /* Ignored */;
  ConstraintSatisfaction Satisfaction;
  if (S.CheckFunctionConstraints(Fn, Satisfaction))
    break;
  S.DiagnoseUnsatisfiedConstraint(Satisfaction);
}
}
11238}

11240static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) {
if (shouldSkipNotingLambdaConversionDecl(Cand->Surrogate))
  return;

// Desugar the type of the surrogate down to a function type,
// retaining as many typedefs as possible while still showing
// the function type (and, therefore, its parameter types).
QualType FnType = Cand->Surrogate->getConversionType();
bool isLValueReference = false;
bool isRValueReference = false;
bool isPointer = false;
if (const LValueReferenceType *FnTypeRef =
      FnType->getAs<LValueReferenceType>()) {
  FnType = FnTypeRef->getPointeeType();
  isLValueReference = true;
} else if (const RValueReferenceType *FnTypeRef =
             FnType->getAs<RValueReferenceType>()) {
  FnType = FnTypeRef->getPointeeType();
  isRValueReference = true;
}
if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) {
  FnType = FnTypePtr->getPointeeType();
  isPointer = true;
}
// Desugar down to a function type.
FnType = QualType(FnType->getAs<FunctionType>(), 0);
// Reconstruct the pointer/reference as appropriate.
if (isPointer) FnType = S.Context.getPointerType(FnType);
if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType);
if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType);

S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand)
  << FnType;
11273}

11275static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc,
                                       SourceLocation OpLoc,
                                       OverloadCandidate *Cand) {
assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary")((void)0);
std::string TypeStr("operator");
TypeStr += Opc;
TypeStr += "(";
TypeStr += Cand->BuiltinParamTypes[0].getAsString();
if (Cand->Conversions.size() == 1) {
  TypeStr += ")";
  S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
} else {
  TypeStr += ", ";
  TypeStr += Cand->BuiltinParamTypes[1].getAsString();
  TypeStr += ")";
  S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
}
11292}

11294static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc,
                                       OverloadCandidate *Cand) {
for (const ImplicitConversionSequence &ICS : Cand->Conversions) {
  if (ICS.isBad()) break; // all meaningless after first invalid
  if (!ICS.isAmbiguous()) continue;

  ICS.DiagnoseAmbiguousConversion(
      S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion));
}
11303}

11305static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) {
if (Cand->Function)
  return Cand->Function->getLocation();
if (Cand->IsSurrogate)
  return Cand->Surrogate->getLocation();
return SourceLocation();
11311}

11313static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) {
switch ((Sema::TemplateDeductionResult)DFI.Result) {
case Sema::TDK_Success:
case Sema::TDK_NonDependentConversionFailure:
  llvm_unreachable("non-deduction failure while diagnosing bad deduction")__builtin_unreachable();

case Sema::TDK_Invalid:
case Sema::TDK_Incomplete:
case Sema::TDK_IncompletePack:
  return 1;

case Sema::TDK_Underqualified:
case Sema::TDK_Inconsistent:
  return 2;

case Sema::TDK_SubstitutionFailure:
case Sema::TDK_DeducedMismatch:
case Sema::TDK_ConstraintsNotSatisfied:
case Sema::TDK_DeducedMismatchNested:
case Sema::TDK_NonDeducedMismatch:
case Sema::TDK_MiscellaneousDeductionFailure:
case Sema::TDK_CUDATargetMismatch:
  return 3;

case Sema::TDK_InstantiationDepth:
  return 4;

case Sema::TDK_InvalidExplicitArguments:
  return 5;

case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
  return 6;
}
llvm_unreachable("Unhandled deduction result")__builtin_unreachable();
11348}

11350namespace {
11351struct CompareOverloadCandidatesForDisplay {
Sema &S;
SourceLocation Loc;
size_t NumArgs;
OverloadCandidateSet::CandidateSetKind CSK;

CompareOverloadCandidatesForDisplay(
    Sema &S, SourceLocation Loc, size_t NArgs,
    OverloadCandidateSet::CandidateSetKind CSK)
    : S(S), NumArgs(NArgs), CSK(CSK) {}

OverloadFailureKind EffectiveFailureKind(const OverloadCandidate *C) const {
  // If there are too many or too few arguments, that's the high-order bit we
  // want to sort by, even if the immediate failure kind was something else.
  if (C->FailureKind == ovl_fail_too_many_arguments ||
      C->FailureKind == ovl_fail_too_few_arguments)
    return static_cast<OverloadFailureKind>(C->FailureKind);

  if (C->Function) {
    if (NumArgs > C->Function->getNumParams() && !C->Function->isVariadic())
      return ovl_fail_too_many_arguments;
    if (NumArgs < C->Function->getMinRequiredArguments())
      return ovl_fail_too_few_arguments;
  }

  return static_cast<OverloadFailureKind>(C->FailureKind);
}

bool operator()(const OverloadCandidate *L,
                const OverloadCandidate *R) {
  // Fast-path this check.
  if (L == R) return false;

  // Order first by viability.
  if (L->Viable) {
    if (!R->Viable) return true;

    // TODO: introduce a tri-valued comparison for overload
    // candidates.  Would be more worthwhile if we had a sort
    // that could exploit it.
    if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK))
      return true;
    if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK))
      return false;
  } else if (R->Viable)
    return false;

  assert(L->Viable == R->Viable)((void)0);

  // Criteria by which we can sort non-viable candidates:
  if (!L->Viable) {
    OverloadFailureKind LFailureKind = EffectiveFailureKind(L);
    OverloadFailureKind RFailureKind = EffectiveFailureKind(R);

    // 1. Arity mismatches come after other candidates.
    if (LFailureKind == ovl_fail_too_many_arguments ||
        LFailureKind == ovl_fail_too_few_arguments) {
      if (RFailureKind == ovl_fail_too_many_arguments ||
          RFailureKind == ovl_fail_too_few_arguments) {
        int LDist = std::abs((int)L->getNumParams() - (int)NumArgs);
        int RDist = std::abs((int)R->getNumParams() - (int)NumArgs);
        if (LDist == RDist) {
          if (LFailureKind == RFailureKind)
            // Sort non-surrogates before surrogates.
            return !L->IsSurrogate && R->IsSurrogate;
          // Sort candidates requiring fewer parameters than there were
          // arguments given after candidates requiring more parameters
          // than there were arguments given.
          return LFailureKind == ovl_fail_too_many_arguments;
        }
        return LDist < RDist;
      }
      return false;
    }
    if (RFailureKind == ovl_fail_too_many_arguments ||
        RFailureKind == ovl_fail_too_few_arguments)
      return true;

    // 2. Bad conversions come first and are ordered by the number
    // of bad conversions and quality of good conversions.
    if (LFailureKind == ovl_fail_bad_conversion) {
      if (RFailureKind != ovl_fail_bad_conversion)
        return true;

      // The conversion that can be fixed with a smaller number of changes,
      // comes first.
      unsigned numLFixes = L->Fix.NumConversionsFixed;
      unsigned numRFixes = R->Fix.NumConversionsFixed;
      numLFixes = (numLFixes == 0) ? UINT_MAX(2147483647 *2U +1U) : numLFixes;
      numRFixes = (numRFixes == 0) ? UINT_MAX(2147483647 *2U +1U) : numRFixes;
      if (numLFixes != numRFixes) {
        return numLFixes < numRFixes;
      }

      // If there's any ordering between the defined conversions...
      // FIXME: this might not be transitive.
      assert(L->Conversions.size() == R->Conversions.size())((void)0);

      int leftBetter = 0;
      unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument);
      for (unsigned E = L->Conversions.size(); I != E; ++I) {
        switch (CompareImplicitConversionSequences(S, Loc,
                                                   L->Conversions[I],
                                                   R->Conversions[I])) {
        case ImplicitConversionSequence::Better:
          leftBetter++;
          break;

        case ImplicitConversionSequence::Worse:
          leftBetter--;
          break;

        case ImplicitConversionSequence::Indistinguishable:
          break;
        }
      }
      if (leftBetter > 0) return true;
      if (leftBetter < 0) return false;

    } else if (RFailureKind == ovl_fail_bad_conversion)
      return false;

    if (LFailureKind == ovl_fail_bad_deduction) {
      if (RFailureKind != ovl_fail_bad_deduction)
        return true;

      if (L->DeductionFailure.Result != R->DeductionFailure.Result)
        return RankDeductionFailure(L->DeductionFailure)
             < RankDeductionFailure(R->DeductionFailure);
    } else if (RFailureKind == ovl_fail_bad_deduction)
      return false;

    // TODO: others?
  }

  // Sort everything else by location.
  SourceLocation LLoc = GetLocationForCandidate(L);
  SourceLocation RLoc = GetLocationForCandidate(R);

  // Put candidates without locations (e.g. builtins) at the end.
  if (LLoc.isInvalid()) return false;
  if (RLoc.isInvalid()) return true;

  return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
}
11496};
11497}

11499/// CompleteNonViableCandidate - Normally, overload resolution only
11500/// computes up to the first bad conversion. Produces the FixIt set if
11501/// possible.
11502static void
11503CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand,
                         ArrayRef<Expr *> Args,
                         OverloadCandidateSet::CandidateSetKind CSK) {
assert(!Cand->Viable)((void)0);

// Don't do anything on failures other than bad conversion.
if (Cand->FailureKind != ovl_fail_bad_conversion)
  return;

// We only want the FixIts if all the arguments can be corrected.
bool Unfixable = false;
// Use a implicit copy initialization to check conversion fixes.
Cand->Fix.setConversionChecker(TryCopyInitialization);

// Attempt to fix the bad conversion.
unsigned ConvCount = Cand->Conversions.size();
for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/;
     ++ConvIdx) {
  assert(ConvIdx != ConvCount && "no bad conversion in candidate")((void)0);
  if (Cand->Conversions[ConvIdx].isInitialized() &&
      Cand->Conversions[ConvIdx].isBad()) {
    Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
    break;
  }
}

// FIXME: this should probably be preserved from the overload
// operation somehow.
bool SuppressUserConversions = false;

unsigned ConvIdx = 0;
unsigned ArgIdx = 0;
ArrayRef<QualType> ParamTypes;
bool Reversed = Cand->isReversed();

if (Cand->IsSurrogate) {
  QualType ConvType
    = Cand->Surrogate->getConversionType().getNonReferenceType();
  if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
    ConvType = ConvPtrType->getPointeeType();
  ParamTypes = ConvType->castAs<FunctionProtoType>()->getParamTypes();
  // Conversion 0 is 'this', which doesn't have a corresponding parameter.
  ConvIdx = 1;
} else if (Cand->Function) {
  ParamTypes =
      Cand->Function->getType()->castAs<FunctionProtoType>()->getParamTypes();
  if (isa<CXXMethodDecl>(Cand->Function) &&
      !isa<CXXConstructorDecl>(Cand->Function) && !Reversed) {
    // Conversion 0 is 'this', which doesn't have a corresponding parameter.
    ConvIdx = 1;
    if (CSK == OverloadCandidateSet::CSK_Operator &&
        Cand->Function->getDeclName().getCXXOverloadedOperator() != OO_Call)
      // Argument 0 is 'this', which doesn't have a corresponding parameter.
      ArgIdx = 1;
  }
} else {
  // Builtin operator.
  assert(ConvCount <= 3)((void)0);
  ParamTypes = Cand->BuiltinParamTypes;
}

// Fill in the rest of the conversions.
for (unsigned ParamIdx = Reversed ? ParamTypes.size() - 1 : 0;
     ConvIdx != ConvCount;
     ++ConvIdx, ++ArgIdx, ParamIdx += (Reversed ? -1 : 1)) {
  assert(ArgIdx < Args.size() && "no argument for this arg conversion")((void)0);
  if (Cand->Conversions[ConvIdx].isInitialized()) {
    // We've already checked this conversion.
  } else if (ParamIdx < ParamTypes.size()) {
    if (ParamTypes[ParamIdx]->isDependentType())
      Cand->Conversions[ConvIdx].setAsIdentityConversion(
          Args[ArgIdx]->getType());
    else {
      Cand->Conversions[ConvIdx] =
          TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ParamIdx],
                                SuppressUserConversions,
                                /*InOverloadResolution=*/true,
                                /*AllowObjCWritebackConversion=*/
                                S.getLangOpts().ObjCAutoRefCount);
      // Store the FixIt in the candidate if it exists.
      if (!Unfixable && Cand->Conversions[ConvIdx].isBad())
        Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
    }
  } else
    Cand->Conversions[ConvIdx].setEllipsis();
}
11589}

11591SmallVector<OverloadCandidate *, 32> OverloadCandidateSet::CompleteCandidates(
  Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
  SourceLocation OpLoc,
  llvm::function_ref<bool(OverloadCandidate &)> Filter) {
// Sort the candidates by viability and position.  Sorting directly would
// be prohibitive, so we make a set of pointers and sort those.
SmallVector<OverloadCandidate*, 32> Cands;
if (OCD == OCD_AllCandidates) Cands.reserve(size());
for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
  if (!Filter(*Cand))
    continue;
  switch (OCD) {
  case OCD_AllCandidates:
    if (!Cand->Viable) {
      if (!Cand->Function && !Cand->IsSurrogate) {
        // This a non-viable builtin candidate.  We do not, in general,
        // want to list every possible builtin candidate.
        continue;
      }
      CompleteNonViableCandidate(S, Cand, Args, Kind);
    }
    break;

  case OCD_ViableCandidates:
    if (!Cand->Viable)
      continue;
    break;

  case OCD_AmbiguousCandidates:
    if (!Cand->Best)
      continue;
    break;
  }

  Cands.push_back(Cand);
}

llvm::stable_sort(
    Cands, CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind));

return Cands;
11632}

11634bool OverloadCandidateSet::shouldDeferDiags(Sema &S, ArrayRef<Expr *> Args,
                                          SourceLocation OpLoc) {
bool DeferHint = false;
if (S.getLangOpts().CUDA && S.getLangOpts().GPUDeferDiag) {
  // Defer diagnostic for CUDA/HIP if there are wrong-sided candidates or
  // host device candidates.
  auto WrongSidedCands =
      CompleteCandidates(S, OCD_AllCandidates, Args, OpLoc, [](auto &Cand) {
        return (Cand.Viable == false &&
                Cand.FailureKind == ovl_fail_bad_target) ||
               (Cand.Function &&
                Cand.Function->template hasAttr<CUDAHostAttr>() &&
                Cand.Function->template hasAttr<CUDADeviceAttr>());
      });
  DeferHint = !WrongSidedCands.empty();
}
return DeferHint;
11651}

11653/// When overload resolution fails, prints diagnostic messages containing the
11654/// candidates in the candidate set.
11655void OverloadCandidateSet::NoteCandidates(
  PartialDiagnosticAt PD, Sema &S, OverloadCandidateDisplayKind OCD,
  ArrayRef<Expr *> Args, StringRef Opc, SourceLocation OpLoc,
  llvm::function_ref<bool(OverloadCandidate &)> Filter) {

auto Cands = CompleteCandidates(S, OCD, Args, OpLoc, Filter);

S.Diag(PD.first, PD.second, shouldDeferDiags(S, Args, OpLoc));

NoteCandidates(S, Args, Cands, Opc, OpLoc);

if (OCD == OCD_AmbiguousCandidates)
  MaybeDiagnoseAmbiguousConstraints(S, {begin(), end()});
11668}

11670void OverloadCandidateSet::NoteCandidates(Sema &S, ArrayRef<Expr *> Args,
                                        ArrayRef<OverloadCandidate *> Cands,
                                        StringRef Opc, SourceLocation OpLoc) {
bool ReportedAmbiguousConversions = false;

const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
unsigned CandsShown = 0;
auto I = Cands.begin(), E = Cands.end();
for (; I != E; ++I) {
  OverloadCandidate *Cand = *I;

  if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow() &&
      ShowOverloads == Ovl_Best) {
    break;
  }
  ++CandsShown;

  if (Cand->Function)
    NoteFunctionCandidate(S, Cand, Args.size(),
                          /*TakingCandidateAddress=*/false, DestAS);
  else if (Cand->IsSurrogate)
    NoteSurrogateCandidate(S, Cand);
  else {
    assert(Cand->Viable &&((void)0)
           "Non-viable built-in candidates are not added to Cands.")((void)0);
    // Generally we only see ambiguities including viable builtin
    // operators if overload resolution got screwed up by an
    // ambiguous user-defined conversion.
    //
    // FIXME: It's quite possible for different conversions to see
    // different ambiguities, though.
    if (!ReportedAmbiguousConversions) {
      NoteAmbiguousUserConversions(S, OpLoc, Cand);
      ReportedAmbiguousConversions = true;
    }

    // If this is a viable builtin, print it.
    NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand);
  }
}

// Inform S.Diags that we've shown an overload set with N elements.  This may
// inform the future value of S.Diags.getNumOverloadCandidatesToShow().
S.Diags.overloadCandidatesShown(CandsShown);

if (I != E)
  S.Diag(OpLoc, diag::note_ovl_too_many_candidates,
         shouldDeferDiags(S, Args, OpLoc))
      << int(E - I);
11719}

11721static SourceLocation
11722GetLocationForCandidate(const TemplateSpecCandidate *Cand) {
return Cand->Specialization ? Cand->Specialization->getLocation()
                            : SourceLocation();
11725}

11727namespace {
11728struct CompareTemplateSpecCandidatesForDisplay {
Sema &S;
CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {}

bool operator()(const TemplateSpecCandidate *L,
                const TemplateSpecCandidate *R) {
  // Fast-path this check.
  if (L == R)
    return false;

  // Assuming that both candidates are not matches...

  // Sort by the ranking of deduction failures.
  if (L->DeductionFailure.Result != R->DeductionFailure.Result)
    return RankDeductionFailure(L->DeductionFailure) <
           RankDeductionFailure(R->DeductionFailure);

  // Sort everything else by location.
  SourceLocation LLoc = GetLocationForCandidate(L);
  SourceLocation RLoc = GetLocationForCandidate(R);

  // Put candidates without locations (e.g. builtins) at the end.
  if (LLoc.isInvalid())
    return false;
  if (RLoc.isInvalid())
    return true;

  return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
}
11757};
11758}

11760/// Diagnose a template argument deduction failure.
11761/// We are treating these failures as overload failures due to bad
11762/// deductions.
11763void TemplateSpecCandidate::NoteDeductionFailure(Sema &S,
                                               bool ForTakingAddress) {
DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern
                     DeductionFailure, /*NumArgs=*/0, ForTakingAddress);
11767}

11769void TemplateSpecCandidateSet::destroyCandidates() {
for (iterator i = begin(), e = end(); i != e; ++i) {
  i->DeductionFailure.Destroy();
}
11773}

11775void TemplateSpecCandidateSet::clear() {
destroyCandidates();
Candidates.clear();
11778}

11780/// NoteCandidates - When no template specialization match is found, prints
11781/// diagnostic messages containing the non-matching specializations that form
11782/// the candidate set.
11783/// This is analoguous to OverloadCandidateSet::NoteCandidates() with
11784/// OCD == OCD_AllCandidates and Cand->Viable == false.
11785void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) {
// Sort the candidates by position (assuming no candidate is a match).
// Sorting directly would be prohibitive, so we make a set of pointers
// and sort those.
SmallVector<TemplateSpecCandidate *, 32> Cands;
Cands.reserve(size());
for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
  if (Cand->Specialization)
    Cands.push_back(Cand);
  // Otherwise, this is a non-matching builtin candidate.  We do not,
  // in general, want to list every possible builtin candidate.
}

llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S));

// FIXME: Perhaps rename OverloadsShown and getShowOverloads()
// for generalization purposes (?).
const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();

SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E;
unsigned CandsShown = 0;
for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
  TemplateSpecCandidate *Cand = *I;

  // Set an arbitrary limit on the number of candidates we'll spam
  // the user with.  FIXME: This limit should depend on details of the
  // candidate list.
  if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
    break;
  ++CandsShown;

  assert(Cand->Specialization &&((void)0)
         "Non-matching built-in candidates are not added to Cands.")((void)0);
  Cand->NoteDeductionFailure(S, ForTakingAddress);
}

if (I != E)
  S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I);
11823}

11825// [PossiblyAFunctionType]  -->   [Return]
11826// NonFunctionType --> NonFunctionType
11827// R (A) --> R(A)
11828// R (*)(A) --> R (A)
11829// R (&)(A) --> R (A)
11830// R (S::*)(A) --> R (A)
11831QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) {
QualType Ret = PossiblyAFunctionType;
if (const PointerType *ToTypePtr =
  PossiblyAFunctionType->getAs<PointerType>())
  Ret = ToTypePtr->getPointeeType();
else if (const ReferenceType *ToTypeRef =
  PossiblyAFunctionType->getAs<ReferenceType>())
  Ret = ToTypeRef->getPointeeType();
else if (const MemberPointerType *MemTypePtr =
  PossiblyAFunctionType->getAs<MemberPointerType>())
  Ret = MemTypePtr->getPointeeType();
Ret =
  Context.getCanonicalType(Ret).getUnqualifiedType();
return Ret;
11845}

11847static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc,
                               bool Complain = true) {
if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
    S.DeduceReturnType(FD, Loc, Complain))
  return true;

auto *FPT = FD->getType()->castAs<FunctionProtoType>();
if (S.getLangOpts().CPlusPlus17 &&
    isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
    !S.ResolveExceptionSpec(Loc, FPT))
  return true;

return false;
11860}

11862namespace {
11863// A helper class to help with address of function resolution
11864// - allows us to avoid passing around all those ugly parameters
11865class AddressOfFunctionResolver {
Sema& S;
Expr* SourceExpr;
const QualType& TargetType;
QualType TargetFunctionType; // Extracted function type from target type

bool Complain;
//DeclAccessPair& ResultFunctionAccessPair;
ASTContext& Context;

bool TargetTypeIsNonStaticMemberFunction;
bool FoundNonTemplateFunction;
bool StaticMemberFunctionFromBoundPointer;
bool HasComplained;

OverloadExpr::FindResult OvlExprInfo;
OverloadExpr *OvlExpr;
TemplateArgumentListInfo OvlExplicitTemplateArgs;
SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches;
TemplateSpecCandidateSet FailedCandidates;

11886public:
AddressOfFunctionResolver(Sema &S, Expr *SourceExpr,
                          const QualType &TargetType, bool Complain)
    : S(S), SourceExpr(SourceExpr), TargetType(TargetType),
      Complain(Complain), Context(S.getASTContext()),
      TargetTypeIsNonStaticMemberFunction(
          !!TargetType->getAs<MemberPointerType>()),
      FoundNonTemplateFunction(false),
      StaticMemberFunctionFromBoundPointer(false),
      HasComplained(false),
      OvlExprInfo(OverloadExpr::find(SourceExpr)),
      OvlExpr(OvlExprInfo.Expression),
      FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) {
  ExtractUnqualifiedFunctionTypeFromTargetType();

  if (TargetFunctionType->isFunctionType()) {
    if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr))
      if (!UME->isImplicitAccess() &&
          !S.ResolveSingleFunctionTemplateSpecialization(UME))
        StaticMemberFunctionFromBoundPointer = true;
  } else if (OvlExpr->hasExplicitTemplateArgs()) {
    DeclAccessPair dap;
    if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization(
            OvlExpr, false, &dap)) {
      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
        if (!Method->isStatic()) {
          // If the target type is a non-function type and the function found
          // is a non-static member function, pretend as if that was the
          // target, it's the only possible type to end up with.
          TargetTypeIsNonStaticMemberFunction = true;

          // And skip adding the function if its not in the proper form.
          // We'll diagnose this due to an empty set of functions.
          if (!OvlExprInfo.HasFormOfMemberPointer)
            return;
        }

      Matches.push_back(std::make_pair(dap, Fn));
    }
    return;
  }

  if (OvlExpr->hasExplicitTemplateArgs())
    OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs);

  if (FindAllFunctionsThatMatchTargetTypeExactly()) {
    // C++ [over.over]p4:
    //   If more than one function is selected, [...]
    if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) {
      if (FoundNonTemplateFunction)
        EliminateAllTemplateMatches();
      else
        EliminateAllExceptMostSpecializedTemplate();
    }
  }

  if (S.getLangOpts().CUDA && Matches.size() > 1)
    EliminateSuboptimalCudaMatches();
}

bool hasComplained() const { return HasComplained; }

11948private:
bool candidateHasExactlyCorrectType(const FunctionDecl *FD) {
  QualType Discard;
  return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) ||
         S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard);
}

/// \return true if A is considered a better overload candidate for the
/// desired type than B.
bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) {
  // If A doesn't have exactly the correct type, we don't want to classify it
  // as "better" than anything else. This way, the user is required to
  // disambiguate for us if there are multiple candidates and no exact match.
  return candidateHasExactlyCorrectType(A) &&
         (!candidateHasExactlyCorrectType(B) ||
          compareEnableIfAttrs(S, A, B) == Comparison::Better);
}

/// \return true if we were able to eliminate all but one overload candidate,
/// false otherwise.
bool eliminiateSuboptimalOverloadCandidates() {
  // Same algorithm as overload resolution -- one pass to pick the "best",
  // another pass to be sure that nothing is better than the best.
  auto Best = Matches.begin();
  for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I)
    if (isBetterCandidate(I->second, Best->second))
      Best = I;

  const FunctionDecl *BestFn = Best->second;
  auto IsBestOrInferiorToBest = [this, BestFn](
      const std::pair<DeclAccessPair, FunctionDecl *> &Pair) {
    return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second);
  };

  // Note: We explicitly leave Matches unmodified if there isn't a clear best
  // option, so we can potentially give the user a better error
  if (!llvm::all_of(Matches, IsBestOrInferiorToBest))
    return false;
  Matches[0] = *Best;
  Matches.resize(1);
  return true;
}

bool isTargetTypeAFunction() const {
  return TargetFunctionType->isFunctionType();
}

// [ToType]     [Return]

// R (*)(A) --> R (A), IsNonStaticMemberFunction = false
// R (&)(A) --> R (A), IsNonStaticMemberFunction = false
// R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true
void inline ExtractUnqualifiedFunctionTypeFromTargetType() {
  TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType);
}

// return true if any matching specializations were found
bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate,
                                 const DeclAccessPair& CurAccessFunPair) {
  if (CXXMethodDecl *Method
            = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) {
    // Skip non-static function templates when converting to pointer, and
    // static when converting to member pointer.
    if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
      return false;
  }
  else if (TargetTypeIsNonStaticMemberFunction)
    return false;

  // C++ [over.over]p2:
  //   If the name is a function template, template argument deduction is
  //   done (14.8.2.2), and if the argument deduction succeeds, the
  //   resulting template argument list is used to generate a single
  //   function template specialization, which is added to the set of
  //   overloaded functions considered.
  FunctionDecl *Specialization = nullptr;
  TemplateDeductionInfo Info(FailedCandidates.getLocation());
  if (Sema::TemplateDeductionResult Result
        = S.DeduceTemplateArguments(FunctionTemplate,
                                    &OvlExplicitTemplateArgs,
                                    TargetFunctionType, Specialization,
                                    Info, /*IsAddressOfFunction*/true)) {
    // Make a note of the failed deduction for diagnostics.
    FailedCandidates.addCandidate()
        .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(),
             MakeDeductionFailureInfo(Context, Result, Info));
    return false;
  }

  // Template argument deduction ensures that we have an exact match or
  // compatible pointer-to-function arguments that would be adjusted by ICS.
  // This function template specicalization works.
  assert(S.isSameOrCompatibleFunctionType(((void)0)
            Context.getCanonicalType(Specialization->getType()),((void)0)
            Context.getCanonicalType(TargetFunctionType)))((void)0);

  if (!S.checkAddressOfFunctionIsAvailable(Specialization))
    return false;

  Matches.push_back(std::make_pair(CurAccessFunPair, Specialization));
  return true;
}

bool AddMatchingNonTemplateFunction(NamedDecl* Fn,
                                    const DeclAccessPair& CurAccessFunPair) {
  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
    // Skip non-static functions when converting to pointer, and static
    // when converting to member pointer.
    if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
      return false;
  }
  else if (TargetTypeIsNonStaticMemberFunction)
    return false;

  if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) {
    if (S.getLangOpts().CUDA)
      if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext))
        if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl))
          return false;
    if (FunDecl->isMultiVersion()) {
      const auto *TA = FunDecl->getAttr<TargetAttr>();
      if (TA && !TA->isDefaultVersion())
        return false;
    }

    // If any candidate has a placeholder return type, trigger its deduction
    // now.
    if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(),
                             Complain)) {
      HasComplained |= Complain;
      return false;
    }

    if (!S.checkAddressOfFunctionIsAvailable(FunDecl))
      return false;

    // If we're in C, we need to support types that aren't exactly identical.
    if (!S.getLangOpts().CPlusPlus ||
        candidateHasExactlyCorrectType(FunDecl)) {
      Matches.push_back(std::make_pair(
          CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl())));
      FoundNonTemplateFunction = true;
      return true;
    }
  }

  return false;
}

bool FindAllFunctionsThatMatchTargetTypeExactly() {
  bool Ret = false;

  // If the overload expression doesn't have the form of a pointer to
  // member, don't try to convert it to a pointer-to-member type.
  if (IsInvalidFormOfPointerToMemberFunction())
    return false;

  for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
                             E = OvlExpr->decls_end();
       I != E; ++I) {
    // Look through any using declarations to find the underlying function.
    NamedDecl *Fn = (*I)->getUnderlyingDecl();

    // C++ [over.over]p3:
    //   Non-member functions and static member functions match
    //   targets of type "pointer-to-function" or "reference-to-function."
    //   Nonstatic member functions match targets of
    //   type "pointer-to-member-function."
    // Note that according to DR 247, the containing class does not matter.
    if (FunctionTemplateDecl *FunctionTemplate
                                      = dyn_cast<FunctionTemplateDecl>(Fn)) {
      if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair()))
        Ret = true;
    }
    // If we have explicit template arguments supplied, skip non-templates.
    else if (!OvlExpr->hasExplicitTemplateArgs() &&
             AddMatchingNonTemplateFunction(Fn, I.getPair()))
      Ret = true;
  }
  assert(Ret || Matches.empty())((void)0);
  return Ret;
}

void EliminateAllExceptMostSpecializedTemplate() {
  //   [...] and any given function template specialization F1 is
  //   eliminated if the set contains a second function template
  //   specialization whose function template is more specialized
  //   than the function template of F1 according to the partial
  //   ordering rules of 14.5.5.2.

  // The algorithm specified above is quadratic. We instead use a
  // two-pass algorithm (similar to the one used to identify the
  // best viable function in an overload set) that identifies the
  // best function template (if it exists).

  UnresolvedSet<4> MatchesCopy; // TODO: avoid!
  for (unsigned I = 0, E = Matches.size(); I != E; ++I)
    MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess());

  // TODO: It looks like FailedCandidates does not serve much purpose
  // here, since the no_viable diagnostic has index 0.
  UnresolvedSetIterator Result = S.getMostSpecialized(
      MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates,
      SourceExpr->getBeginLoc(), S.PDiag(),
      S.PDiag(diag::err_addr_ovl_ambiguous)
          << Matches[0].second->getDeclName(),
      S.PDiag(diag::note_ovl_candidate)
          << (unsigned)oc_function << (unsigned)ocs_described_template,
      Complain, TargetFunctionType);

  if (Result != MatchesCopy.end()) {
    // Make it the first and only element
    Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
    Matches[0].second = cast<FunctionDecl>(*Result);
    Matches.resize(1);
  } else
    HasComplained |= Complain;
}

void EliminateAllTemplateMatches() {
  //   [...] any function template specializations in the set are
  //   eliminated if the set also contains a non-template function, [...]
  for (unsigned I = 0, N = Matches.size(); I != N; ) {
    if (Matches[I].second->getPrimaryTemplate() == nullptr)
      ++I;
    else {
      Matches[I] = Matches[--N];
      Matches.resize(N);
    }
  }
}

void EliminateSuboptimalCudaMatches() {
  S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches);
}

12184public:
void ComplainNoMatchesFound() const {
  assert(Matches.empty())((void)0);
  S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable)
      << OvlExpr->getName() << TargetFunctionType
      << OvlExpr->getSourceRange();
  if (FailedCandidates.empty())
    S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
                                /*TakingAddress=*/true);
  else {
    // We have some deduction failure messages. Use them to diagnose
    // the function templates, and diagnose the non-template candidates
    // normally.
    for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
                               IEnd = OvlExpr->decls_end();
         I != IEnd; ++I)
      if (FunctionDecl *Fun =
              dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()))
        if (!functionHasPassObjectSizeParams(Fun))
          S.NoteOverloadCandidate(*I, Fun, CRK_None, TargetFunctionType,
                                  /*TakingAddress=*/true);
    FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc());
  }
}

bool IsInvalidFormOfPointerToMemberFunction() const {
  return TargetTypeIsNonStaticMemberFunction &&
    !OvlExprInfo.HasFormOfMemberPointer;
}

void ComplainIsInvalidFormOfPointerToMemberFunction() const {
    // TODO: Should we condition this on whether any functions might
    // have matched, or is it more appropriate to do that in callers?
    // TODO: a fixit wouldn't hurt.
    S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier)
      << TargetType << OvlExpr->getSourceRange();
}

bool IsStaticMemberFunctionFromBoundPointer() const {
  return StaticMemberFunctionFromBoundPointer;
}

void ComplainIsStaticMemberFunctionFromBoundPointer() const {
  S.Diag(OvlExpr->getBeginLoc(),
         diag::err_invalid_form_pointer_member_function)
      << OvlExpr->getSourceRange();
}

void ComplainOfInvalidConversion() const {
  S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref)
      << OvlExpr->getName() << TargetType;
}

void ComplainMultipleMatchesFound() const {
  assert(Matches.size() > 1)((void)0);
  S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous)
      << OvlExpr->getName() << OvlExpr->getSourceRange();
  S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
                              /*TakingAddress=*/true);
}

bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); }

int getNumMatches() const { return Matches.size(); }

FunctionDecl* getMatchingFunctionDecl() const {
  if (Matches.size() != 1) return nullptr;
  return Matches[0].second;
}

const DeclAccessPair* getMatchingFunctionAccessPair() const {
  if (Matches.size() != 1) return nullptr;
  return &Matches[0].first;
}
12258};
12259}

12261/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
12262/// an overloaded function (C++ [over.over]), where @p From is an
12263/// expression with overloaded function type and @p ToType is the type
12264/// we're trying to resolve to. For example:
12265///
12266/// @code
12267/// int f(double);
12268/// int f(int);
12269///
12270/// int (*pfd)(double) = f; // selects f(double)
12271/// @endcode
12272///
12273/// This routine returns the resulting FunctionDecl if it could be
12274/// resolved, and NULL otherwise. When @p Complain is true, this
12275/// routine will emit diagnostics if there is an error.
12276FunctionDecl *
12277Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                       QualType TargetType,
                                       bool Complain,
                                       DeclAccessPair &FoundResult,
                                       bool *pHadMultipleCandidates) {
assert(AddressOfExpr->getType() == Context.OverloadTy)((void)0);

AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType,
                                   Complain);
int NumMatches = Resolver.getNumMatches();
FunctionDecl *Fn = nullptr;
bool ShouldComplain = Complain && !Resolver.hasComplained();
if (NumMatches == 0 && ShouldComplain) {
  if (Resolver.IsInvalidFormOfPointerToMemberFunction())
    Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
  else
    Resolver.ComplainNoMatchesFound();
}
else if (NumMatches > 1 && ShouldComplain)
  Resolver.ComplainMultipleMatchesFound();
else if (NumMatches == 1) {
  Fn = Resolver.getMatchingFunctionDecl();
  assert(Fn)((void)0);
  if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
    ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT);
  FoundResult = *Resolver.getMatchingFunctionAccessPair();
  if (Complain) {
    if (Resolver.IsStaticMemberFunctionFromBoundPointer())
      Resolver.ComplainIsStaticMemberFunctionFromBoundPointer();
    else
      CheckAddressOfMemberAccess(AddressOfExpr, FoundResult);
  }
}

if (pHadMultipleCandidates)
  *pHadMultipleCandidates = Resolver.hadMultipleCandidates();
return Fn;
12314}

12316/// Given an expression that refers to an overloaded function, try to
12317/// resolve that function to a single function that can have its address taken.
12318/// This will modify `Pair` iff it returns non-null.
12319///
12320/// This routine can only succeed if from all of the candidates in the overload
12321/// set for SrcExpr that can have their addresses taken, there is one candidate
12322/// that is more constrained than the rest.
12323FunctionDecl *
12324Sema::resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &Pair) {
OverloadExpr::FindResult R = OverloadExpr::find(E);
OverloadExpr *Ovl = R.Expression;
bool IsResultAmbiguous = false;
FunctionDecl *Result = nullptr;
DeclAccessPair DAP;
SmallVector<FunctionDecl *, 2> AmbiguousDecls;

auto CheckMoreConstrained =
    [&] (FunctionDecl *FD1, FunctionDecl *FD2) -> Optional<bool> {
      SmallVector<const Expr *, 1> AC1, AC2;
      FD1->getAssociatedConstraints(AC1);
      FD2->getAssociatedConstraints(AC2);
      bool AtLeastAsConstrained1, AtLeastAsConstrained2;
      if (IsAtLeastAsConstrained(FD1, AC1, FD2, AC2, AtLeastAsConstrained1))
        return None;
      if (IsAtLeastAsConstrained(FD2, AC2, FD1, AC1, AtLeastAsConstrained2))
        return None;
      if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
        return None;
      return AtLeastAsConstrained1;
    };

// Don't use the AddressOfResolver because we're specifically looking for
// cases where we have one overload candidate that lacks
// enable_if/pass_object_size/...
for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
  auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
  if (!FD)
    return nullptr;

  if (!checkAddressOfFunctionIsAvailable(FD))
    continue;

  // We have more than one result - see if it is more constrained than the
  // previous one.
  if (Result) {
    Optional<bool> MoreConstrainedThanPrevious = CheckMoreConstrained(FD,
                                                                      Result);
    if (!MoreConstrainedThanPrevious) {
      IsResultAmbiguous = true;
      AmbiguousDecls.push_back(FD);
      continue;
    }
    if (!*MoreConstrainedThanPrevious)
      continue;
    // FD is more constrained - replace Result with it.
  }
  IsResultAmbiguous = false;
  DAP = I.getPair();
  Result = FD;
}

if (IsResultAmbiguous)
  return nullptr;

if (Result) {
  SmallVector<const Expr *, 1> ResultAC;
  // We skipped over some ambiguous declarations which might be ambiguous with
  // the selected result.
  for (FunctionDecl *Skipped : AmbiguousDecls)
    if (!CheckMoreConstrained(Skipped, Result).hasValue())
      return nullptr;
  Pair = DAP;
}
return Result;
12390}

12392/// Given an overloaded function, tries to turn it into a non-overloaded
12393/// function reference using resolveAddressOfSingleOverloadCandidate. This
12394/// will perform access checks, diagnose the use of the resultant decl, and, if
12395/// requested, potentially perform a function-to-pointer decay.
12396///
12397/// Returns false if resolveAddressOfSingleOverloadCandidate fails.
12398/// Otherwise, returns true. This may emit diagnostics and return true.
12399bool Sema::resolveAndFixAddressOfSingleOverloadCandidate(
  ExprResult &SrcExpr, bool DoFunctionPointerConverion) {
Expr *E = SrcExpr.get();
assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload")((void)0);

DeclAccessPair DAP;
FunctionDecl *Found = resolveAddressOfSingleOverloadCandidate(E, DAP);
if (!Found || Found->isCPUDispatchMultiVersion() ||
    Found->isCPUSpecificMultiVersion())
  return false;

// Emitting multiple diagnostics for a function that is both inaccessible and
// unavailable is consistent with our behavior elsewhere. So, always check
// for both.
DiagnoseUseOfDecl(Found, E->getExprLoc());
CheckAddressOfMemberAccess(E, DAP);
Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found);
if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType())
  SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
else
  SrcExpr = Fixed;
return true;
12421}

12423/// Given an expression that refers to an overloaded function, try to
12424/// resolve that overloaded function expression down to a single function.
12425///
12426/// This routine can only resolve template-ids that refer to a single function
12427/// template, where that template-id refers to a single template whose template
12428/// arguments are either provided by the template-id or have defaults,
12429/// as described in C++0x [temp.arg.explicit]p3.
12430///
12431/// If no template-ids are found, no diagnostics are emitted and NULL is
12432/// returned.
12433FunctionDecl *
12434Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
                                                bool Complain,
                                                DeclAccessPair *FoundResult) {
// C++ [over.over]p1:
//   [...] [Note: any redundant set of parentheses surrounding the
//   overloaded function name is ignored (5.1). ]
// C++ [over.over]p1:
//   [...] The overloaded function name can be preceded by the &
//   operator.

// If we didn't actually find any template-ids, we're done.
if (!ovl->hasExplicitTemplateArgs())
  return nullptr;

TemplateArgumentListInfo ExplicitTemplateArgs;
ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc());

// Look through all of the overloaded functions, searching for one
// whose type matches exactly.
FunctionDecl *Matched = nullptr;
for (UnresolvedSetIterator I = ovl->decls_begin(),
       E = ovl->decls_end(); I != E; ++I) {
  // C++0x [temp.arg.explicit]p3:
  //   [...] In contexts where deduction is done and fails, or in contexts
  //   where deduction is not done, if a template argument list is
  //   specified and it, along with any default template arguments,
  //   identifies a single function template specialization, then the
  //   template-id is an lvalue for the function template specialization.
  FunctionTemplateDecl *FunctionTemplate
    = cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl());

  // C++ [over.over]p2:
  //   If the name is a function template, template argument deduction is
  //   done (14.8.2.2), and if the argument deduction succeeds, the
  //   resulting template argument list is used to generate a single
  //   function template specialization, which is added to the set of
  //   overloaded functions considered.
  FunctionDecl *Specialization = nullptr;
  TemplateDeductionInfo Info(FailedCandidates.getLocation());
  if (TemplateDeductionResult Result
        = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs,
                                  Specialization, Info,
                                  /*IsAddressOfFunction*/true)) {
    // Make a note of the failed deduction for diagnostics.
    // TODO: Actually use the failed-deduction info?
    FailedCandidates.addCandidate()
        .set(I.getPair(), FunctionTemplate->getTemplatedDecl(),
             MakeDeductionFailureInfo(Context, Result, Info));
    continue;
  }

  assert(Specialization && "no specialization and no error?")((void)0);

  // Multiple matches; we can't resolve to a single declaration.
  if (Matched) {
    if (Complain) {
      Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous)
        << ovl->getName();
      NoteAllOverloadCandidates(ovl);
    }
    return nullptr;
  }

  Matched = Specialization;
  if (FoundResult) *FoundResult = I.getPair();
}

if (Matched &&
    completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain))
  return nullptr;

return Matched;
12507}

12509// Resolve and fix an overloaded expression that can be resolved
12510// because it identifies a single function template specialization.
12511//
12512// Last three arguments should only be supplied if Complain = true
12513//
12514// Return true if it was logically possible to so resolve the
12515// expression, regardless of whether or not it succeeded.  Always
12516// returns true if 'complain' is set.
12517bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization(
                    ExprResult &SrcExpr, bool doFunctionPointerConverion,
                    bool complain, SourceRange OpRangeForComplaining,
                                         QualType DestTypeForComplaining,
                                          unsigned DiagIDForComplaining) {
assert(SrcExpr.get()->getType() == Context.OverloadTy)((void)0);

OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get());

DeclAccessPair found;
ExprResult SingleFunctionExpression;
if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization(
                         ovl.Expression, /*complain*/ false, &found)) {
  if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) {
    SrcExpr = ExprError();
    return true;
  }

  // It is only correct to resolve to an instance method if we're
  // resolving a form that's permitted to be a pointer to member.
  // Otherwise we'll end up making a bound member expression, which
  // is illegal in all the contexts we resolve like this.
  if (!ovl.HasFormOfMemberPointer &&
      isa<CXXMethodDecl>(fn) &&
      cast<CXXMethodDecl>(fn)->isInstance()) {
    if (!complain) return false;

    Diag(ovl.Expression->getExprLoc(),
         diag::err_bound_member_function)
      << 0 << ovl.Expression->getSourceRange();

    // TODO: I believe we only end up here if there's a mix of
    // static and non-static candidates (otherwise the expression
    // would have 'bound member' type, not 'overload' type).
    // Ideally we would note which candidate was chosen and why
    // the static candidates were rejected.
    SrcExpr = ExprError();
    return true;
  }

  // Fix the expression to refer to 'fn'.
  SingleFunctionExpression =
      FixOverloadedFunctionReference(SrcExpr.get(), found, fn);

  // If desired, do function-to-pointer decay.
  if (doFunctionPointerConverion) {
    SingleFunctionExpression =
      DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get());
    if (SingleFunctionExpression.isInvalid()) {
      SrcExpr = ExprError();
      return true;
    }
  }
}

if (!SingleFunctionExpression.isUsable()) {
  if (complain) {
    Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining)
      << ovl.Expression->getName()
      << DestTypeForComplaining
      << OpRangeForComplaining
      << ovl.Expression->getQualifierLoc().getSourceRange();
    NoteAllOverloadCandidates(SrcExpr.get());

    SrcExpr = ExprError();
    return true;
  }

  return false;
}

SrcExpr = SingleFunctionExpression;
return true;
12590}

12592/// Add a single candidate to the overload set.
12593static void AddOverloadedCallCandidate(Sema &S,
                                     DeclAccessPair FoundDecl,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                                     ArrayRef<Expr *> Args,
                                     OverloadCandidateSet &CandidateSet,
                                     bool PartialOverloading,
                                     bool KnownValid) {
NamedDecl *Callee = FoundDecl.getDecl();
if (isa<UsingShadowDecl>(Callee))
  Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl();

if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) {
  if (ExplicitTemplateArgs) {
    assert(!KnownValid && "Explicit template arguments?")((void)0);
    return;
  }
  // Prevent ill-formed function decls to be added as overload candidates.
  if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>()))
    return;

  S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet,
                         /*SuppressUserConversions=*/false,
                         PartialOverloading);
  return;
}

if (FunctionTemplateDecl *FuncTemplate
    = dyn_cast<FunctionTemplateDecl>(Callee)) {
  S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl,
                                 ExplicitTemplateArgs, Args, CandidateSet,
                                 /*SuppressUserConversions=*/false,
                                 PartialOverloading);
  return;
}

assert(!KnownValid && "unhandled case in overloaded call candidate")((void)0);
12629}

12631/// Add the overload candidates named by callee and/or found by argument
12632/// dependent lookup to the given overload set.
12633void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
                                     ArrayRef<Expr *> Args,
                                     OverloadCandidateSet &CandidateSet,
                                     bool PartialOverloading) {

12638#ifndef NDEBUG1
// Verify that ArgumentDependentLookup is consistent with the rules
// in C++0x [basic.lookup.argdep]p3:
//
//   Let X be the lookup set produced by unqualified lookup (3.4.1)
//   and let Y be the lookup set produced by argument dependent
//   lookup (defined as follows). If X contains
//
//     -- a declaration of a class member, or
//
//     -- a block-scope function declaration that is not a
//        using-declaration, or
//
//     -- a declaration that is neither a function or a function
//        template
//
//   then Y is empty.

if (ULE->requiresADL()) {
  for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
         E = ULE->decls_end(); I != E; ++I) {
    assert(!(*I)->getDeclContext()->isRecord())((void)0);
    assert(isa<UsingShadowDecl>(*I) ||((void)0)
           !(*I)->getDeclContext()->isFunctionOrMethod())((void)0);
    assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate())((void)0);
  }
}
12665#endif

// It would be nice to avoid this copy.
TemplateArgumentListInfo TABuffer;
TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
if (ULE->hasExplicitTemplateArgs()) {
  ULE->copyTemplateArgumentsInto(TABuffer);
  ExplicitTemplateArgs = &TABuffer;
}

for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
       E = ULE->decls_end(); I != E; ++I)
  AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
                             CandidateSet, PartialOverloading,
                             /*KnownValid*/ true);

if (ULE->requiresADL())
  AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(),
                                       Args, ExplicitTemplateArgs,
                                       CandidateSet, PartialOverloading);
12685}

12687/// Add the call candidates from the given set of lookup results to the given
12688/// overload set. Non-function lookup results are ignored.
12689void Sema::AddOverloadedCallCandidates(
  LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
  ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet) {
for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
  AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
                             CandidateSet, false, /*KnownValid*/ false);
12695}

12697/// Determine whether a declaration with the specified name could be moved into
12698/// a different namespace.
12699static bool canBeDeclaredInNamespace(const DeclarationName &Name) {
switch (Name.getCXXOverloadedOperator()) {
case OO_New: case OO_Array_New:
case OO_Delete: case OO_Array_Delete:
  return false;

default:
  return true;
}
12708}

12710/// Attempt to recover from an ill-formed use of a non-dependent name in a
12711/// template, where the non-dependent name was declared after the template
12712/// was defined. This is common in code written for a compilers which do not
12713/// correctly implement two-stage name lookup.
12714///
12715/// Returns true if a viable candidate was found and a diagnostic was issued.
12716static bool DiagnoseTwoPhaseLookup(
  Sema &SemaRef, SourceLocation FnLoc, const CXXScopeSpec &SS,
  LookupResult &R, OverloadCandidateSet::CandidateSetKind CSK,
  TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
  CXXRecordDecl **FoundInClass = nullptr) {
if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty())
  return false;

for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) {
  if (DC->isTransparentContext())
    continue;

  SemaRef.LookupQualifiedName(R, DC);

  if (!R.empty()) {
    R.suppressDiagnostics();

    OverloadCandidateSet Candidates(FnLoc, CSK);
    SemaRef.AddOverloadedCallCandidates(R, ExplicitTemplateArgs, Args,
                                        Candidates);

    OverloadCandidateSet::iterator Best;
    OverloadingResult OR =
        Candidates.BestViableFunction(SemaRef, FnLoc, Best);

    if (auto *RD = dyn_cast<CXXRecordDecl>(DC)) {
      // We either found non-function declarations or a best viable function
      // at class scope. A class-scope lookup result disables ADL. Don't
      // look past this, but let the caller know that we found something that
      // either is, or might be, usable in this class.
      if (FoundInClass) {
        *FoundInClass = RD;
        if (OR == OR_Success) {
          R.clear();
          R.addDecl(Best->FoundDecl.getDecl(), Best->FoundDecl.getAccess());
          R.resolveKind();
        }
      }
      return false;
    }

    if (OR != OR_Success) {
      // There wasn't a unique best function or function template.
      return false;
    }

    // Find the namespaces where ADL would have looked, and suggest
    // declaring the function there instead.
    Sema::AssociatedNamespaceSet AssociatedNamespaces;
    Sema::AssociatedClassSet AssociatedClasses;
    SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args,
                                               AssociatedNamespaces,
                                               AssociatedClasses);
    Sema::AssociatedNamespaceSet SuggestedNamespaces;
    if (canBeDeclaredInNamespace(R.getLookupName())) {
      DeclContext *Std = SemaRef.getStdNamespace();
      for (Sema::AssociatedNamespaceSet::iterator
             it = AssociatedNamespaces.begin(),
             end = AssociatedNamespaces.end(); it != end; ++it) {
        // Never suggest declaring a function within namespace 'std'.
        if (Std && Std->Encloses(*it))
          continue;

        // Never suggest declaring a function within a namespace with a
        // reserved name, like __gnu_cxx.
        NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it);
        if (NS &&
            NS->getQualifiedNameAsString().find("__") != std::string::npos)
          continue;

        SuggestedNamespaces.insert(*it);
      }
    }

    SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup)
      << R.getLookupName();
    if (SuggestedNamespaces.empty()) {
      SemaRef.Diag(Best->Function->getLocation(),
                   diag::note_not_found_by_two_phase_lookup)
        << R.getLookupName() << 0;
    } else if (SuggestedNamespaces.size() == 1) {
      SemaRef.Diag(Best->Function->getLocation(),
                   diag::note_not_found_by_two_phase_lookup)
        << R.getLookupName() << 1 << *SuggestedNamespaces.begin();
    } else {
      // FIXME: It would be useful to list the associated namespaces here,
      // but the diagnostics infrastructure doesn't provide a way to produce
      // a localized representation of a list of items.
      SemaRef.Diag(Best->Function->getLocation(),
                   diag::note_not_found_by_two_phase_lookup)
        << R.getLookupName() << 2;
    }

    // Try to recover by calling this function.
    return true;
  }

  R.clear();
}

return false;
12817}

12819/// Attempt to recover from ill-formed use of a non-dependent operator in a
12820/// template, where the non-dependent operator was declared after the template
12821/// was defined.
12822///
12823/// Returns true if a viable candidate was found and a diagnostic was issued.
12824static bool
12825DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op,
                             SourceLocation OpLoc,
                             ArrayRef<Expr *> Args) {
DeclarationName OpName =
  SemaRef.Context.DeclarationNames.getCXXOperatorName(Op);
LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName);
return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R,
                              OverloadCandidateSet::CSK_Operator,
                              /*ExplicitTemplateArgs=*/nullptr, Args);
12834}

12836namespace {
12837class BuildRecoveryCallExprRAII {
Sema &SemaRef;
12839public:
BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) {
  assert(SemaRef.IsBuildingRecoveryCallExpr == false)((void)0);
  SemaRef.IsBuildingRecoveryCallExpr = true;
}

~BuildRecoveryCallExprRAII() {
  SemaRef.IsBuildingRecoveryCallExpr = false;
}
12848};

12850}

12852/// Attempts to recover from a call where no functions were found.
12853///
12854/// This function will do one of three things:
12855///  * Diagnose, recover, and return a recovery expression.
12856///  * Diagnose, fail to recover, and return ExprError().
12857///  * Do not diagnose, do not recover, and return ExprResult(). The caller is
12858///    expected to diagnose as appropriate.
12859static ExprResult
12860BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
                    UnresolvedLookupExpr *ULE,
                    SourceLocation LParenLoc,
                    MutableArrayRef<Expr *> Args,
                    SourceLocation RParenLoc,
                    bool EmptyLookup, bool AllowTypoCorrection) {
// Do not try to recover if it is already building a recovery call.
// This stops infinite loops for template instantiations like
//
// template <typename T> auto foo(T t) -> decltype(foo(t)) {}
// template <typename T> auto foo(T t) -> decltype(foo(&t)) {}
if (SemaRef.IsBuildingRecoveryCallExpr)
  return ExprResult();
BuildRecoveryCallExprRAII RCE(SemaRef);

CXXScopeSpec SS;
SS.Adopt(ULE->getQualifierLoc());
SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc();

TemplateArgumentListInfo TABuffer;
TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
if (ULE->hasExplicitTemplateArgs()) {
  ULE->copyTemplateArgumentsInto(TABuffer);
  ExplicitTemplateArgs = &TABuffer;
}

LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(),
               Sema::LookupOrdinaryName);
CXXRecordDecl *FoundInClass = nullptr;
if (DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R,
                           OverloadCandidateSet::CSK_Normal,
                           ExplicitTemplateArgs, Args, &FoundInClass)) {
  // OK, diagnosed a two-phase lookup issue.
} else if (EmptyLookup) {
  // Try to recover from an empty lookup with typo correction.
  R.clear();
  NoTypoCorrectionCCC NoTypoValidator{};
  FunctionCallFilterCCC FunctionCallValidator(SemaRef, Args.size(),
                                              ExplicitTemplateArgs != nullptr,
                                              dyn_cast<MemberExpr>(Fn));
  CorrectionCandidateCallback &Validator =
      AllowTypoCorrection
          ? static_cast<CorrectionCandidateCallback &>(FunctionCallValidator)
          : static_cast<CorrectionCandidateCallback &>(NoTypoValidator);
  if (SemaRef.DiagnoseEmptyLookup(S, SS, R, Validator, ExplicitTemplateArgs,
                                  Args))
    return ExprError();
} else if (FoundInClass && SemaRef.getLangOpts().MSVCCompat) {
  // We found a usable declaration of the name in a dependent base of some
  // enclosing class.
  // FIXME: We should also explain why the candidates found by name lookup
  // were not viable.
  if (SemaRef.DiagnoseDependentMemberLookup(R))
    return ExprError();
} else {
  // We had viable candidates and couldn't recover; let the caller diagnose
  // this.
  return ExprResult();
}

// If we get here, we should have issued a diagnostic and formed a recovery
// lookup result.
assert(!R.empty() && "lookup results empty despite recovery")((void)0);

// If recovery created an ambiguity, just bail out.
if (R.isAmbiguous()) {
  R.suppressDiagnostics();
  return ExprError();
}

// Build an implicit member call if appropriate.  Just drop the
// casts and such from the call, we don't really care.
ExprResult NewFn = ExprError();
if ((*R.begin())->isCXXClassMember())
  NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R,
                                                  ExplicitTemplateArgs, S);
else if (ExplicitTemplateArgs || TemplateKWLoc.isValid())
  NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false,
                                      ExplicitTemplateArgs);
else
  NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false);

if (NewFn.isInvalid())
  return ExprError();

// This shouldn't cause an infinite loop because we're giving it
// an expression with viable lookup results, which should never
// end up here.
return SemaRef.BuildCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc,
                             MultiExprArg(Args.data(), Args.size()),
                             RParenLoc);
12951}

12953/// Constructs and populates an OverloadedCandidateSet from
12954/// the given function.
12955/// \returns true when an the ExprResult output parameter has been set.
12956bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn,
                                UnresolvedLookupExpr *ULE,
                                MultiExprArg Args,
                                SourceLocation RParenLoc,
                                OverloadCandidateSet *CandidateSet,
                                ExprResult *Result) {
12962#ifndef NDEBUG1
if (ULE->requiresADL()) {
  // To do ADL, we must have found an unqualified name.
  assert(!ULE->getQualifier() && "qualified name with ADL")((void)0);

  // We don't perform ADL for implicit declarations of builtins.
  // Verify that this was correctly set up.
  FunctionDecl *F;
  if (ULE->decls_begin() != ULE->decls_end() &&
      ULE->decls_begin() + 1 == ULE->decls_end() &&
      (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) &&
      F->getBuiltinID() && F->isImplicit())
    llvm_unreachable("performing ADL for builtin")__builtin_unreachable();

  // We don't perform ADL in C.
  assert(getLangOpts().CPlusPlus && "ADL enabled in C")((void)0);
}
12979#endif

UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) {
7
←
Taking false branch→
  *Result = ExprError();
  return true;
}

// Add the functions denoted by the callee to the set of candidate
// functions, including those from argument-dependent lookup.
AddOverloadedCallCandidates(ULE, Args, *CandidateSet);

if (getLangOpts().MSVCCompat &&
8
←
Assuming field 'MSVCCompat' is not equal to 0→
13
←
Taking true branch→
    CurContext->isDependentContext() && !isSFINAEContext() &&
9
←
Assuming the condition is true→
10
←
Assuming the condition is true→
    (isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) {
11
←
Assuming field 'CurContext' is not a 'FunctionDecl'→
12
←
Assuming field 'CurContext' is a 'CXXRecordDecl'→

  OverloadCandidateSet::iterator Best;
  if (CandidateSet->empty() ||
14
←
Assuming the condition is false→
      CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) ==
15
←
Calling 'OverloadCandidateSet::BestViableFunction'→
          OR_No_Viable_Function) {
    // In Microsoft mode, if we are inside a template class member function
    // then create a type dependent CallExpr. The goal is to postpone name
    // lookup to instantiation time to be able to search into type dependent
    // base classes.
    CallExpr *CE =
        CallExpr::Create(Context, Fn, Args, Context.DependentTy, VK_PRValue,
                         RParenLoc, CurFPFeatureOverrides());
    CE->markDependentForPostponedNameLookup();
    *Result = CE;
    return true;
  }
}

if (CandidateSet->empty())
  return false;

UnbridgedCasts.restore();
return false;
13017}

13019// Guess at what the return type for an unresolvable overload should be.
13020static QualType chooseRecoveryType(OverloadCandidateSet &CS,
                                 OverloadCandidateSet::iterator *Best) {
llvm::Optional<QualType> Result;
// Adjust Type after seeing a candidate.
auto ConsiderCandidate = [&](const OverloadCandidate &Candidate) {
  if (!Candidate.Function)
    return;
  if (Candidate.Function->isInvalidDecl())
    return;
  QualType T = Candidate.Function->getReturnType();
  if (T.isNull())
    return;
  if (!Result)
    Result = T;
  else if (Result != T)
    Result = QualType();
};

// Look for an unambiguous type from a progressively larger subset.
// e.g. if types disagree, but all *viable* overloads return int, choose int.
//
// First, consider only the best candidate.
if (Best && *Best != CS.end())
  ConsiderCandidate(**Best);
// Next, consider only viable candidates.
if (!Result)
  for (const auto &C : CS)
    if (C.Viable)
      ConsiderCandidate(C);
// Finally, consider all candidates.
if (!Result)
  for (const auto &C : CS)
    ConsiderCandidate(C);

if (!Result)
  return QualType();
auto Value = Result.getValue();
if (Value.isNull() || Value->isUndeducedType())
  return QualType();
return Value;
13060}

13062/// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns
13063/// the completed call expression. If overload resolution fails, emits
13064/// diagnostics and returns ExprError()
13065static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
                                         UnresolvedLookupExpr *ULE,
                                         SourceLocation LParenLoc,
                                         MultiExprArg Args,
                                         SourceLocation RParenLoc,
                                         Expr *ExecConfig,
                                         OverloadCandidateSet *CandidateSet,
                                         OverloadCandidateSet::iterator *Best,
                                         OverloadingResult OverloadResult,
                                         bool AllowTypoCorrection) {
switch (OverloadResult) {
case OR_Success: {
  FunctionDecl *FDecl = (*Best)->Function;
  SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl);
  if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc()))
    return ExprError();
  Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
  return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
                                       ExecConfig, /*IsExecConfig=*/false,
                                       (*Best)->IsADLCandidate);
}

case OR_No_Viable_Function: {
  // Try to recover by looking for viable functions which the user might
  // have meant to call.
  ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc,
                                              Args, RParenLoc,
                                              CandidateSet->empty(),
                                              AllowTypoCorrection);
  if (Recovery.isInvalid() || Recovery.isUsable())
    return Recovery;

  // If the user passes in a function that we can't take the address of, we
  // generally end up emitting really bad error messages. Here, we attempt to
  // emit better ones.
  for (const Expr *Arg : Args) {
    if (!Arg->getType()->isFunctionType())
      continue;
    if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) {
      auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
      if (FD &&
          !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
                                                     Arg->getExprLoc()))
        return ExprError();
    }
  }

  CandidateSet->NoteCandidates(
      PartialDiagnosticAt(
          Fn->getBeginLoc(),
          SemaRef.PDiag(diag::err_ovl_no_viable_function_in_call)
              << ULE->getName() << Fn->getSourceRange()),
      SemaRef, OCD_AllCandidates, Args);
  break;
}

case OR_Ambiguous:
  CandidateSet->NoteCandidates(
      PartialDiagnosticAt(Fn->getBeginLoc(),
                          SemaRef.PDiag(diag::err_ovl_ambiguous_call)
                              << ULE->getName() << Fn->getSourceRange()),
      SemaRef, OCD_AmbiguousCandidates, Args);
  break;

case OR_Deleted: {
  CandidateSet->NoteCandidates(
      PartialDiagnosticAt(Fn->getBeginLoc(),
                          SemaRef.PDiag(diag::err_ovl_deleted_call)
                              << ULE->getName() << Fn->getSourceRange()),
      SemaRef, OCD_AllCandidates, Args);

  // We emitted an error for the unavailable/deleted function call but keep
  // the call in the AST.
  FunctionDecl *FDecl = (*Best)->Function;
  Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
  return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
                                       ExecConfig, /*IsExecConfig=*/false,
                                       (*Best)->IsADLCandidate);
}
}

// Overload resolution failed, try to recover.
SmallVector<Expr *, 8> SubExprs = {Fn};
SubExprs.append(Args.begin(), Args.end());
return SemaRef.CreateRecoveryExpr(Fn->getBeginLoc(), RParenLoc, SubExprs,
                                  chooseRecoveryType(*CandidateSet, Best));
13151}

13153static void markUnaddressableCandidatesUnviable(Sema &S,
                                              OverloadCandidateSet &CS) {
for (auto I = CS.begin(), E = CS.end(); I != E; ++I) {
  if (I->Viable &&
      !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) {
    I->Viable = false;
    I->FailureKind = ovl_fail_addr_not_available;
  }
}
13162}

13164/// BuildOverloadedCallExpr - Given the call expression that calls Fn
13165/// (which eventually refers to the declaration Func) and the call
13166/// arguments Args/NumArgs, attempt to resolve the function call down
13167/// to a specific function. If overload resolution succeeds, returns
13168/// the call expression produced by overload resolution.
13169/// Otherwise, emits diagnostics and returns ExprError.
13170ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn,
                                       UnresolvedLookupExpr *ULE,
                                       SourceLocation LParenLoc,
                                       MultiExprArg Args,
                                       SourceLocation RParenLoc,
                                       Expr *ExecConfig,
                                       bool AllowTypoCorrection,
                                       bool CalleesAddressIsTaken) {
OverloadCandidateSet CandidateSet(Fn->getExprLoc(),
                                  OverloadCandidateSet::CSK_Normal);
ExprResult result;

if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet,
                           &result))
  return result;

// If the user handed us something like `(&Foo)(Bar)`, we need to ensure that
// functions that aren't addressible are considered unviable.
if (CalleesAddressIsTaken)
  markUnaddressableCandidatesUnviable(*this, CandidateSet);

OverloadCandidateSet::iterator Best;
OverloadingResult OverloadResult =
    CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best);

return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, RParenLoc,
                                ExecConfig, &CandidateSet, &Best,
                                OverloadResult, AllowTypoCorrection);
13198}

13200static bool IsOverloaded(const UnresolvedSetImpl &Functions) {
return Functions.size() > 1 ||
       (Functions.size() == 1 &&
        isa<FunctionTemplateDecl>((*Functions.begin())->getUnderlyingDecl()));
13204}

13206ExprResult Sema::CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
                                          NestedNameSpecifierLoc NNSLoc,
                                          DeclarationNameInfo DNI,
                                          const UnresolvedSetImpl &Fns,
                                          bool PerformADL) {
return UnresolvedLookupExpr::Create(Context, NamingClass, NNSLoc, DNI,
                                    PerformADL, IsOverloaded(Fns),
                                    Fns.begin(), Fns.end());
13214}

13216/// Create a unary operation that may resolve to an overloaded
13217/// operator.
13218///
13219/// \param OpLoc The location of the operator itself (e.g., '*').
13220///
13221/// \param Opc The UnaryOperatorKind that describes this operator.
13222///
13223/// \param Fns The set of non-member functions that will be
13224/// considered by overload resolution. The caller needs to build this
13225/// set based on the context using, e.g.,
13226/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13227/// set should not contain any member functions; those will be added
13228/// by CreateOverloadedUnaryOp().
13229///
13230/// \param Input The input argument.
13231ExprResult
13232Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
                            const UnresolvedSetImpl &Fns,
                            Expr *Input, bool PerformADL) {
OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc);
assert(Op != OO_None && "Invalid opcode for overloaded unary operator")((void)0);
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
// TODO: provide better source location info.
DeclarationNameInfo OpNameInfo(OpName, OpLoc);

if (checkPlaceholderForOverload(*this, Input))
  return ExprError();

Expr *Args[2] = { Input, nullptr };
unsigned NumArgs = 1;

// For post-increment and post-decrement, add the implicit '0' as
// the second argument, so that we know this is a post-increment or
// post-decrement.
if (Opc == UO_PostInc || Opc == UO_PostDec) {
  llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
  Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy,
                                   SourceLocation());
  NumArgs = 2;
}

ArrayRef<Expr *> ArgsArray(Args, NumArgs);

if (Input->isTypeDependent()) {
  if (Fns.empty())
    return UnaryOperator::Create(Context, Input, Opc, Context.DependentTy,
                                 VK_PRValue, OK_Ordinary, OpLoc, false,
                                 CurFPFeatureOverrides());

  CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
  ExprResult Fn = CreateUnresolvedLookupExpr(
      NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns);
  if (Fn.isInvalid())
    return ExprError();
  return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), ArgsArray,
                                     Context.DependentTy, VK_PRValue, OpLoc,
                                     CurFPFeatureOverrides());
}

// Build an empty overload set.
OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);

// Add the candidates from the given function set.
AddNonMemberOperatorCandidates(Fns, ArgsArray, CandidateSet);

// Add operator candidates that are member functions.
AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);

// Add candidates from ADL.
if (PerformADL) {
  AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray,
                                       /*ExplicitTemplateArgs*/nullptr,
                                       CandidateSet);
}

// Add builtin operator candidates.
AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
case OR_Success: {
  // We found a built-in operator or an overloaded operator.
  FunctionDecl *FnDecl = Best->Function;

  if (FnDecl) {
    Expr *Base = nullptr;
    // We matched an overloaded operator. Build a call to that
    // operator.

    // Convert the arguments.
    if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
      CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl);

      ExprResult InputRes =
        PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr,
                                            Best->FoundDecl, Method);
      if (InputRes.isInvalid())
        return ExprError();
      Base = Input = InputRes.get();
    } else {
      // Convert the arguments.
      ExprResult InputInit
        = PerformCopyInitialization(InitializedEntity::InitializeParameter(
                                                    Context,
                                                    FnDecl->getParamDecl(0)),
                                    SourceLocation(),
                                    Input);
      if (InputInit.isInvalid())
        return ExprError();
      Input = InputInit.get();
    }

    // Build the actual expression node.
    ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl,
                                              Base, HadMultipleCandidates,
                                              OpLoc);
    if (FnExpr.isInvalid())
      return ExprError();

    // Determine the result type.
    QualType ResultTy = FnDecl->getReturnType();
    ExprValueKind VK = Expr::getValueKindForType(ResultTy);
    ResultTy = ResultTy.getNonLValueExprType(Context);

    Args[0] = Input;
    CallExpr *TheCall = CXXOperatorCallExpr::Create(
        Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc,
        CurFPFeatureOverrides(), Best->IsADLCandidate);

    if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl))
      return ExprError();

    if (CheckFunctionCall(FnDecl, TheCall,
                          FnDecl->getType()->castAs<FunctionProtoType>()))
      return ExprError();
    return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), FnDecl);
  } else {
    // We matched a built-in operator. Convert the arguments, then
    // break out so that we will build the appropriate built-in
    // operator node.
    ExprResult InputRes = PerformImplicitConversion(
        Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing,
        CCK_ForBuiltinOverloadedOp);
    if (InputRes.isInvalid())
      return ExprError();
    Input = InputRes.get();
    break;
  }
}

case OR_No_Viable_Function:
  // This is an erroneous use of an operator which can be overloaded by
  // a non-member function. Check for non-member operators which were
  // defined too late to be candidates.
  if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray))
    // FIXME: Recover by calling the found function.
    return ExprError();

  // No viable function; fall through to handling this as a
  // built-in operator, which will produce an error message for us.
  break;

case OR_Ambiguous:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(OpLoc,
                          PDiag(diag::err_ovl_ambiguous_oper_unary)
                              << UnaryOperator::getOpcodeStr(Opc)
                              << Input->getType() << Input->getSourceRange()),
      *this, OCD_AmbiguousCandidates, ArgsArray,
      UnaryOperator::getOpcodeStr(Opc), OpLoc);
  return ExprError();

case OR_Deleted:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
                                     << UnaryOperator::getOpcodeStr(Opc)
                                     << Input->getSourceRange()),
      *this, OCD_AllCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc),
      OpLoc);
  return ExprError();
}

// Either we found no viable overloaded operator or we matched a
// built-in operator. In either case, fall through to trying to
// build a built-in operation.
return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
13405}

13407/// Perform lookup for an overloaded binary operator.
13408void Sema::LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
                               OverloadedOperatorKind Op,
                               const UnresolvedSetImpl &Fns,
                               ArrayRef<Expr *> Args, bool PerformADL) {
SourceLocation OpLoc = CandidateSet.getLocation();

OverloadedOperatorKind ExtraOp =
    CandidateSet.getRewriteInfo().AllowRewrittenCandidates
        ? getRewrittenOverloadedOperator(Op)
        : OO_None;

// Add the candidates from the given function set. This also adds the
// rewritten candidates using these functions if necessary.
AddNonMemberOperatorCandidates(Fns, Args, CandidateSet);

// Add operator candidates that are member functions.
AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet);
if (CandidateSet.getRewriteInfo().shouldAddReversed(Op))
  AddMemberOperatorCandidates(Op, OpLoc, {Args[1], Args[0]}, CandidateSet,
                              OverloadCandidateParamOrder::Reversed);

// In C++20, also add any rewritten member candidates.
if (ExtraOp) {
  AddMemberOperatorCandidates(ExtraOp, OpLoc, Args, CandidateSet);
  if (CandidateSet.getRewriteInfo().shouldAddReversed(ExtraOp))
    AddMemberOperatorCandidates(ExtraOp, OpLoc, {Args[1], Args[0]},
                                CandidateSet,
                                OverloadCandidateParamOrder::Reversed);
}

// Add candidates from ADL. Per [over.match.oper]p2, this lookup is not
// performed for an assignment operator (nor for operator[] nor operator->,
// which don't get here).
if (Op != OO_Equal && PerformADL) {
  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
  AddArgumentDependentLookupCandidates(OpName, OpLoc, Args,
                                       /*ExplicitTemplateArgs*/ nullptr,
                                       CandidateSet);
  if (ExtraOp) {
    DeclarationName ExtraOpName =
        Context.DeclarationNames.getCXXOperatorName(ExtraOp);
    AddArgumentDependentLookupCandidates(ExtraOpName, OpLoc, Args,
                                         /*ExplicitTemplateArgs*/ nullptr,
                                         CandidateSet);
  }
}

// Add builtin operator candidates.
//
// FIXME: We don't add any rewritten candidates here. This is strictly
// incorrect; a builtin candidate could be hidden by a non-viable candidate,
// resulting in our selecting a rewritten builtin candidate. For example:
//
//   enum class E { e };
//   bool operator!=(E, E) requires false;
//   bool k = E::e != E::e;
//
// ... should select the rewritten builtin candidate 'operator==(E, E)'. But
// it seems unreasonable to consider rewritten builtin candidates. A core
// issue has been filed proposing to removed this requirement.
AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet);
13469}

13471/// Create a binary operation that may resolve to an overloaded
13472/// operator.
13473///
13474/// \param OpLoc The location of the operator itself (e.g., '+').
13475///
13476/// \param Opc The BinaryOperatorKind that describes this operator.
13477///
13478/// \param Fns The set of non-member functions that will be
13479/// considered by overload resolution. The caller needs to build this
13480/// set based on the context using, e.g.,
13481/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13482/// set should not contain any member functions; those will be added
13483/// by CreateOverloadedBinOp().
13484///
13485/// \param LHS Left-hand argument.
13486/// \param RHS Right-hand argument.
13487/// \param PerformADL Whether to consider operator candidates found by ADL.
13488/// \param AllowRewrittenCandidates Whether to consider candidates found by
13489///        C++20 operator rewrites.
13490/// \param DefaultedFn If we are synthesizing a defaulted operator function,
13491///        the function in question. Such a function is never a candidate in
13492///        our overload resolution. This also enables synthesizing a three-way
13493///        comparison from < and == as described in C++20 [class.spaceship]p1.
13494ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
                                     BinaryOperatorKind Opc,
                                     const UnresolvedSetImpl &Fns, Expr *LHS,
                                     Expr *RHS, bool PerformADL,
                                     bool AllowRewrittenCandidates,
                                     FunctionDecl *DefaultedFn) {
Expr *Args[2] = { LHS, RHS };
LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple

if (!getLangOpts().CPlusPlus20)
  AllowRewrittenCandidates = false;

OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc);

// If either side is type-dependent, create an appropriate dependent
// expression.
if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
  if (Fns.empty()) {
    // If there are no functions to store, just build a dependent
    // BinaryOperator or CompoundAssignment.
    if (BinaryOperator::isCompoundAssignmentOp(Opc))
      return CompoundAssignOperator::Create(
          Context, Args[0], Args[1], Opc, Context.DependentTy, VK_LValue,
          OK_Ordinary, OpLoc, CurFPFeatureOverrides(), Context.DependentTy,
          Context.DependentTy);
    return BinaryOperator::Create(
        Context, Args[0], Args[1], Opc, Context.DependentTy, VK_PRValue,
        OK_Ordinary, OpLoc, CurFPFeatureOverrides());
  }

  // FIXME: save results of ADL from here?
  CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
  // TODO: provide better source location info in DNLoc component.
  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
  DeclarationNameInfo OpNameInfo(OpName, OpLoc);
  ExprResult Fn = CreateUnresolvedLookupExpr(
      NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns, PerformADL);
  if (Fn.isInvalid())
    return ExprError();
  return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), Args,
                                     Context.DependentTy, VK_PRValue, OpLoc,
                                     CurFPFeatureOverrides());
}

// Always do placeholder-like conversions on the RHS.
if (checkPlaceholderForOverload(*this, Args[1]))
  return ExprError();

// Do placeholder-like conversion on the LHS; note that we should
// not get here with a PseudoObject LHS.
assert(Args[0]->getObjectKind() != OK_ObjCProperty)((void)0);
if (checkPlaceholderForOverload(*this, Args[0]))
  return ExprError();

// If this is the assignment operator, we only perform overload resolution
// if the left-hand side is a class or enumeration type. This is actually
// a hack. The standard requires that we do overload resolution between the
// various built-in candidates, but as DR507 points out, this can lead to
// problems. So we do it this way, which pretty much follows what GCC does.
// Note that we go the traditional code path for compound assignment forms.
if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
  return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);

// If this is the .* operator, which is not overloadable, just
// create a built-in binary operator.
if (Opc == BO_PtrMemD)
  return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);

// Build the overload set.
OverloadCandidateSet CandidateSet(
    OpLoc, OverloadCandidateSet::CSK_Operator,
    OverloadCandidateSet::OperatorRewriteInfo(Op, AllowRewrittenCandidates));
if (DefaultedFn)
  CandidateSet.exclude(DefaultedFn);
LookupOverloadedBinOp(CandidateSet, Op, Fns, Args, PerformADL);

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
  case OR_Success: {
    // We found a built-in operator or an overloaded operator.
    FunctionDecl *FnDecl = Best->Function;

    bool IsReversed = Best->isReversed();
    if (IsReversed)
      std::swap(Args[0], Args[1]);

    if (FnDecl) {
      Expr *Base = nullptr;
      // We matched an overloaded operator. Build a call to that
      // operator.

      OverloadedOperatorKind ChosenOp =
          FnDecl->getDeclName().getCXXOverloadedOperator();

      // C++2a [over.match.oper]p9:
      //   If a rewritten operator== candidate is selected by overload
      //   resolution for an operator@, its return type shall be cv bool
      if (Best->RewriteKind && ChosenOp == OO_EqualEqual &&
          !FnDecl->getReturnType()->isBooleanType()) {
        bool IsExtension =
            FnDecl->getReturnType()->isIntegralOrUnscopedEnumerationType();
        Diag(OpLoc, IsExtension ? diag::ext_ovl_rewrite_equalequal_not_bool
                                : diag::err_ovl_rewrite_equalequal_not_bool)
            << FnDecl->getReturnType() << BinaryOperator::getOpcodeStr(Opc)
            << Args[0]->getSourceRange() << Args[1]->getSourceRange();
        Diag(FnDecl->getLocation(), diag::note_declared_at);
        if (!IsExtension)
          return ExprError();
      }

      if (AllowRewrittenCandidates && !IsReversed &&
          CandidateSet.getRewriteInfo().isReversible()) {
        // We could have reversed this operator, but didn't. Check if some
        // reversed form was a viable candidate, and if so, if it had a
        // better conversion for either parameter. If so, this call is
        // formally ambiguous, and allowing it is an extension.
        llvm::SmallVector<FunctionDecl*, 4> AmbiguousWith;
        for (OverloadCandidate &Cand : CandidateSet) {
          if (Cand.Viable && Cand.Function && Cand.isReversed() &&
              haveSameParameterTypes(Context, Cand.Function, FnDecl, 2)) {
            for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
              if (CompareImplicitConversionSequences(
                      *this, OpLoc, Cand.Conversions[ArgIdx],
                      Best->Conversions[ArgIdx]) ==
                  ImplicitConversionSequence::Better) {
                AmbiguousWith.push_back(Cand.Function);
                break;
              }
            }
          }
        }

        if (!AmbiguousWith.empty()) {
          bool AmbiguousWithSelf =
              AmbiguousWith.size() == 1 &&
              declaresSameEntity(AmbiguousWith.front(), FnDecl);
          Diag(OpLoc, diag::ext_ovl_ambiguous_oper_binary_reversed)
              << BinaryOperator::getOpcodeStr(Opc)
              << Args[0]->getType() << Args[1]->getType() << AmbiguousWithSelf
              << Args[0]->getSourceRange() << Args[1]->getSourceRange();
          if (AmbiguousWithSelf) {
            Diag(FnDecl->getLocation(),
                 diag::note_ovl_ambiguous_oper_binary_reversed_self);
          } else {
            Diag(FnDecl->getLocation(),
                 diag::note_ovl_ambiguous_oper_binary_selected_candidate);
            for (auto *F : AmbiguousWith)
              Diag(F->getLocation(),
                   diag::note_ovl_ambiguous_oper_binary_reversed_candidate);
          }
        }
      }

      // Convert the arguments.
      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
        // Best->Access is only meaningful for class members.
        CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl);

        ExprResult Arg1 =
          PerformCopyInitialization(
            InitializedEntity::InitializeParameter(Context,
                                                   FnDecl->getParamDecl(0)),
            SourceLocation(), Args[1]);
        if (Arg1.isInvalid())
          return ExprError();

        ExprResult Arg0 =
          PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
                                              Best->FoundDecl, Method);
        if (Arg0.isInvalid())
          return ExprError();
        Base = Args[0] = Arg0.getAs<Expr>();
        Args[1] = RHS = Arg1.getAs<Expr>();
      } else {
        // Convert the arguments.
        ExprResult Arg0 = PerformCopyInitialization(
          InitializedEntity::InitializeParameter(Context,
                                                 FnDecl->getParamDecl(0)),
          SourceLocation(), Args[0]);
        if (Arg0.isInvalid())
          return ExprError();

        ExprResult Arg1 =
          PerformCopyInitialization(
            InitializedEntity::InitializeParameter(Context,
                                                   FnDecl->getParamDecl(1)),
            SourceLocation(), Args[1]);
        if (Arg1.isInvalid())
          return ExprError();
        Args[0] = LHS = Arg0.getAs<Expr>();
        Args[1] = RHS = Arg1.getAs<Expr>();
      }

      // Build the actual expression node.
      ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
                                                Best->FoundDecl, Base,
                                                HadMultipleCandidates, OpLoc);
      if (FnExpr.isInvalid())
        return ExprError();

      // Determine the result type.
      QualType ResultTy = FnDecl->getReturnType();
      ExprValueKind VK = Expr::getValueKindForType(ResultTy);
      ResultTy = ResultTy.getNonLValueExprType(Context);

      CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
          Context, ChosenOp, FnExpr.get(), Args, ResultTy, VK, OpLoc,
          CurFPFeatureOverrides(), Best->IsADLCandidate);

      if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall,
                              FnDecl))
        return ExprError();

      ArrayRef<const Expr *> ArgsArray(Args, 2);
      const Expr *ImplicitThis = nullptr;
      // Cut off the implicit 'this'.
      if (isa<CXXMethodDecl>(FnDecl)) {
        ImplicitThis = ArgsArray[0];
        ArgsArray = ArgsArray.slice(1);
      }

      // Check for a self move.
      if (Op == OO_Equal)
        DiagnoseSelfMove(Args[0], Args[1], OpLoc);

      if (ImplicitThis) {
        QualType ThisType = Context.getPointerType(ImplicitThis->getType());
        QualType ThisTypeFromDecl = Context.getPointerType(
            cast<CXXMethodDecl>(FnDecl)->getThisObjectType());

        CheckArgAlignment(OpLoc, FnDecl, "'this'", ThisType,
                          ThisTypeFromDecl);
      }

      checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray,
                isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(),
                VariadicDoesNotApply);

      ExprResult R = MaybeBindToTemporary(TheCall);
      if (R.isInvalid())
        return ExprError();

      R = CheckForImmediateInvocation(R, FnDecl);
      if (R.isInvalid())
        return ExprError();

      // For a rewritten candidate, we've already reversed the arguments
      // if needed. Perform the rest of the rewrite now.
      if ((Best->RewriteKind & CRK_DifferentOperator) ||
          (Op == OO_Spaceship && IsReversed)) {
        if (Op == OO_ExclaimEqual) {
          assert(ChosenOp == OO_EqualEqual && "unexpected operator name")((void)0);
          R = CreateBuiltinUnaryOp(OpLoc, UO_LNot, R.get());
        } else {
          assert(ChosenOp == OO_Spaceship && "unexpected operator name")((void)0);
          llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
          Expr *ZeroLiteral =
              IntegerLiteral::Create(Context, Zero, Context.IntTy, OpLoc);

          Sema::CodeSynthesisContext Ctx;
          Ctx.Kind = Sema::CodeSynthesisContext::RewritingOperatorAsSpaceship;
          Ctx.Entity = FnDecl;
          pushCodeSynthesisContext(Ctx);

          R = CreateOverloadedBinOp(
              OpLoc, Opc, Fns, IsReversed ? ZeroLiteral : R.get(),
              IsReversed ? R.get() : ZeroLiteral, PerformADL,
              /*AllowRewrittenCandidates=*/false);

          popCodeSynthesisContext();
        }
        if (R.isInvalid())
          return ExprError();
      } else {
        assert(ChosenOp == Op && "unexpected operator name")((void)0);
      }

      // Make a note in the AST if we did any rewriting.
      if (Best->RewriteKind != CRK_None)
        R = new (Context) CXXRewrittenBinaryOperator(R.get(), IsReversed);

      return R;
    } else {
      // We matched a built-in operator. Convert the arguments, then
      // break out so that we will build the appropriate built-in
      // operator node.
      ExprResult ArgsRes0 = PerformImplicitConversion(
          Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
          AA_Passing, CCK_ForBuiltinOverloadedOp);
      if (ArgsRes0.isInvalid())
        return ExprError();
      Args[0] = ArgsRes0.get();

      ExprResult ArgsRes1 = PerformImplicitConversion(
          Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
          AA_Passing, CCK_ForBuiltinOverloadedOp);
      if (ArgsRes1.isInvalid())
        return ExprError();
      Args[1] = ArgsRes1.get();
      break;
    }
  }

  case OR_No_Viable_Function: {
    // C++ [over.match.oper]p9:
    //   If the operator is the operator , [...] and there are no
    //   viable functions, then the operator is assumed to be the
    //   built-in operator and interpreted according to clause 5.
    if (Opc == BO_Comma)
      break;

    // When defaulting an 'operator<=>', we can try to synthesize a three-way
    // compare result using '==' and '<'.
    if (DefaultedFn && Opc == BO_Cmp) {
      ExprResult E = BuildSynthesizedThreeWayComparison(OpLoc, Fns, Args[0],
                                                        Args[1], DefaultedFn);
      if (E.isInvalid() || E.isUsable())
        return E;
    }

    // For class as left operand for assignment or compound assignment
    // operator do not fall through to handling in built-in, but report that
    // no overloaded assignment operator found
    ExprResult Result = ExprError();
    StringRef OpcStr = BinaryOperator::getOpcodeStr(Opc);
    auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates,
                                                 Args, OpLoc);
    DeferDiagsRAII DDR(*this,
                       CandidateSet.shouldDeferDiags(*this, Args, OpLoc));
    if (Args[0]->getType()->isRecordType() &&
        Opc >= BO_Assign && Opc <= BO_OrAssign) {
      Diag(OpLoc,  diag::err_ovl_no_viable_oper)
           << BinaryOperator::getOpcodeStr(Opc)
           << Args[0]->getSourceRange() << Args[1]->getSourceRange();
      if (Args[0]->getType()->isIncompleteType()) {
        Diag(OpLoc, diag::note_assign_lhs_incomplete)
          << Args[0]->getType()
          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
      }
    } else {
      // This is an erroneous use of an operator which can be overloaded by
      // a non-member function. Check for non-member operators which were
      // defined too late to be candidates.
      if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args))
        // FIXME: Recover by calling the found function.
        return ExprError();

      // No viable function; try to create a built-in operation, which will
      // produce an error. Then, show the non-viable candidates.
      Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
    }
    assert(Result.isInvalid() &&((void)0)
           "C++ binary operator overloading is missing candidates!")((void)0);
    CandidateSet.NoteCandidates(*this, Args, Cands, OpcStr, OpLoc);
    return Result;
  }

  case OR_Ambiguous:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
                                       << BinaryOperator::getOpcodeStr(Opc)
                                       << Args[0]->getType()
                                       << Args[1]->getType()
                                       << Args[0]->getSourceRange()
                                       << Args[1]->getSourceRange()),
        *this, OCD_AmbiguousCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
        OpLoc);
    return ExprError();

  case OR_Deleted:
    if (isImplicitlyDeleted(Best->Function)) {
      FunctionDecl *DeletedFD = Best->Function;
      DefaultedFunctionKind DFK = getDefaultedFunctionKind(DeletedFD);
      if (DFK.isSpecialMember()) {
        Diag(OpLoc, diag::err_ovl_deleted_special_oper)
          << Args[0]->getType() << DFK.asSpecialMember();
      } else {
        assert(DFK.isComparison())((void)0);
        Diag(OpLoc, diag::err_ovl_deleted_comparison)
          << Args[0]->getType() << DeletedFD;
      }

      // The user probably meant to call this special member. Just
      // explain why it's deleted.
      NoteDeletedFunction(DeletedFD);
      return ExprError();
    }
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(
            OpLoc, PDiag(diag::err_ovl_deleted_oper)
                       << getOperatorSpelling(Best->Function->getDeclName()
                                                  .getCXXOverloadedOperator())
                       << Args[0]->getSourceRange()
                       << Args[1]->getSourceRange()),
        *this, OCD_AllCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
        OpLoc);
    return ExprError();
}

// We matched a built-in operator; build it.
return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13898}

13900ExprResult Sema::BuildSynthesizedThreeWayComparison(
  SourceLocation OpLoc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS,
  FunctionDecl *DefaultedFn) {
const ComparisonCategoryInfo *Info =
    Context.CompCategories.lookupInfoForType(DefaultedFn->getReturnType());
// If we're not producing a known comparison category type, we can't
// synthesize a three-way comparison. Let the caller diagnose this.
if (!Info)
  return ExprResult((Expr*)nullptr);

// If we ever want to perform this synthesis more generally, we will need to
// apply the temporary materialization conversion to the operands.
assert(LHS->isGLValue() && RHS->isGLValue() &&((void)0)
       "cannot use prvalue expressions more than once")((void)0);
Expr *OrigLHS = LHS;
Expr *OrigRHS = RHS;

// Replace the LHS and RHS with OpaqueValueExprs; we're going to refer to
// each of them multiple times below.
LHS = new (Context)
    OpaqueValueExpr(LHS->getExprLoc(), LHS->getType(), LHS->getValueKind(),
                    LHS->getObjectKind(), LHS);
RHS = new (Context)
    OpaqueValueExpr(RHS->getExprLoc(), RHS->getType(), RHS->getValueKind(),
                    RHS->getObjectKind(), RHS);

ExprResult Eq = CreateOverloadedBinOp(OpLoc, BO_EQ, Fns, LHS, RHS, true, true,
                                      DefaultedFn);
if (Eq.isInvalid())
  return ExprError();

ExprResult Less = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, LHS, RHS, true,
                                        true, DefaultedFn);
if (Less.isInvalid())
  return ExprError();

ExprResult Greater;
if (Info->isPartial()) {
  Greater = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, RHS, LHS, true, true,
                                  DefaultedFn);
  if (Greater.isInvalid())
    return ExprError();
}

// Form the list of comparisons we're going to perform.
struct Comparison {
  ExprResult Cmp;
  ComparisonCategoryResult Result;
} Comparisons[4] =
{ {Eq, Info->isStrong() ? ComparisonCategoryResult::Equal
                        : ComparisonCategoryResult::Equivalent},
  {Less, ComparisonCategoryResult::Less},
  {Greater, ComparisonCategoryResult::Greater},
  {ExprResult(), ComparisonCategoryResult::Unordered},
};

int I = Info->isPartial() ? 3 : 2;

// Combine the comparisons with suitable conditional expressions.
ExprResult Result;
for (; I >= 0; --I) {
  // Build a reference to the comparison category constant.
  auto *VI = Info->lookupValueInfo(Comparisons[I].Result);
  // FIXME: Missing a constant for a comparison category. Diagnose this?
  if (!VI)
    return ExprResult((Expr*)nullptr);
  ExprResult ThisResult =
      BuildDeclarationNameExpr(CXXScopeSpec(), DeclarationNameInfo(), VI->VD);
  if (ThisResult.isInvalid())
    return ExprError();

  // Build a conditional unless this is the final case.
  if (Result.get()) {
    Result = ActOnConditionalOp(OpLoc, OpLoc, Comparisons[I].Cmp.get(),
                                ThisResult.get(), Result.get());
    if (Result.isInvalid())
      return ExprError();
  } else {
    Result = ThisResult;
  }
}

// Build a PseudoObjectExpr to model the rewriting of an <=> operator, and to
// bind the OpaqueValueExprs before they're (repeatedly) used.
Expr *SyntacticForm = BinaryOperator::Create(
    Context, OrigLHS, OrigRHS, BO_Cmp, Result.get()->getType(),
    Result.get()->getValueKind(), Result.get()->getObjectKind(), OpLoc,
    CurFPFeatureOverrides());
Expr *SemanticForm[] = {LHS, RHS, Result.get()};
return PseudoObjectExpr::Create(Context, SyntacticForm, SemanticForm, 2);
13990}

13992ExprResult
13993Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
                                       SourceLocation RLoc,
                                       Expr *Base, Expr *Idx) {
Expr *Args[2] = { Base, Idx };
DeclarationName OpName =
    Context.DeclarationNames.getCXXOperatorName(OO_Subscript);

// If either side is type-dependent, create an appropriate dependent
// expression.
if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {

  CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
  // CHECKME: no 'operator' keyword?
  DeclarationNameInfo OpNameInfo(OpName, LLoc);
  OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
  ExprResult Fn = CreateUnresolvedLookupExpr(
      NamingClass, NestedNameSpecifierLoc(), OpNameInfo, UnresolvedSet<0>());
  if (Fn.isInvalid())
    return ExprError();
  // Can't add any actual overloads yet

  return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn.get(), Args,
                                     Context.DependentTy, VK_PRValue, RLoc,
                                     CurFPFeatureOverrides());
}

// Handle placeholders on both operands.
if (checkPlaceholderForOverload(*this, Args[0]))
  return ExprError();
if (checkPlaceholderForOverload(*this, Args[1]))
  return ExprError();

// Build an empty overload set.
OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator);

// Subscript can only be overloaded as a member function.

// Add operator candidates that are member functions.
AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);

// Add builtin operator candidates.
AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) {
  case OR_Success: {
    // We found a built-in operator or an overloaded operator.
    FunctionDecl *FnDecl = Best->Function;

    if (FnDecl) {
      // We matched an overloaded operator. Build a call to that
      // operator.

      CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl);

      // Convert the arguments.
      CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
      ExprResult Arg0 =
        PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
                                            Best->FoundDecl, Method);
      if (Arg0.isInvalid())
        return ExprError();
      Args[0] = Arg0.get();

      // Convert the arguments.
      ExprResult InputInit
        = PerformCopyInitialization(InitializedEntity::InitializeParameter(
                                                    Context,
                                                    FnDecl->getParamDecl(0)),
                                    SourceLocation(),
                                    Args[1]);
      if (InputInit.isInvalid())
        return ExprError();

      Args[1] = InputInit.getAs<Expr>();

      // Build the actual expression node.
      DeclarationNameInfo OpLocInfo(OpName, LLoc);
      OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
      ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
                                                Best->FoundDecl,
                                                Base,
                                                HadMultipleCandidates,
                                                OpLocInfo.getLoc(),
                                                OpLocInfo.getInfo());
      if (FnExpr.isInvalid())
        return ExprError();

      // Determine the result type
      QualType ResultTy = FnDecl->getReturnType();
      ExprValueKind VK = Expr::getValueKindForType(ResultTy);
      ResultTy = ResultTy.getNonLValueExprType(Context);

      CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
          Context, OO_Subscript, FnExpr.get(), Args, ResultTy, VK, RLoc,
          CurFPFeatureOverrides());
      if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl))
        return ExprError();

      if (CheckFunctionCall(Method, TheCall,
                            Method->getType()->castAs<FunctionProtoType>()))
        return ExprError();

      return MaybeBindToTemporary(TheCall);
    } else {
      // We matched a built-in operator. Convert the arguments, then
      // break out so that we will build the appropriate built-in
      // operator node.
      ExprResult ArgsRes0 = PerformImplicitConversion(
          Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
          AA_Passing, CCK_ForBuiltinOverloadedOp);
      if (ArgsRes0.isInvalid())
        return ExprError();
      Args[0] = ArgsRes0.get();

      ExprResult ArgsRes1 = PerformImplicitConversion(
          Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
          AA_Passing, CCK_ForBuiltinOverloadedOp);
      if (ArgsRes1.isInvalid())
        return ExprError();
      Args[1] = ArgsRes1.get();

      break;
    }
  }

  case OR_No_Viable_Function: {
    PartialDiagnostic PD = CandidateSet.empty()
        ? (PDiag(diag::err_ovl_no_oper)
           << Args[0]->getType() << /*subscript*/ 0
           << Args[0]->getSourceRange() << Args[1]->getSourceRange())
        : (PDiag(diag::err_ovl_no_viable_subscript)
           << Args[0]->getType() << Args[0]->getSourceRange()
           << Args[1]->getSourceRange());
    CandidateSet.NoteCandidates(PartialDiagnosticAt(LLoc, PD), *this,
                                OCD_AllCandidates, Args, "[]", LLoc);
    return ExprError();
  }

  case OR_Ambiguous:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
                                      << "[]" << Args[0]->getType()
                                      << Args[1]->getType()
                                      << Args[0]->getSourceRange()
                                      << Args[1]->getSourceRange()),
        *this, OCD_AmbiguousCandidates, Args, "[]", LLoc);
    return ExprError();

  case OR_Deleted:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_deleted_oper)
                                      << "[]" << Args[0]->getSourceRange()
                                      << Args[1]->getSourceRange()),
        *this, OCD_AllCandidates, Args, "[]", LLoc);
    return ExprError();
  }

// We matched a built-in operator; build it.
return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc);
14156}

14158/// BuildCallToMemberFunction - Build a call to a member
14159/// function. MemExpr is the expression that refers to the member
14160/// function (and includes the object parameter), Args/NumArgs are the
14161/// arguments to the function call (not including the object
14162/// parameter). The caller needs to validate that the member
14163/// expression refers to a non-static member function or an overloaded
14164/// member function.
14165ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
                                         SourceLocation LParenLoc,
                                         MultiExprArg Args,
                                         SourceLocation RParenLoc,
                                         bool AllowRecovery) {
assert(MemExprE->getType() == Context.BoundMemberTy ||((void)0)
       MemExprE->getType() == Context.OverloadTy)((void)0);

// Dig out the member expression. This holds both the object
// argument and the member function we're referring to.
Expr *NakedMemExpr = MemExprE->IgnoreParens();

// Determine whether this is a call to a pointer-to-member function.
if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) {
  assert(op->getType() == Context.BoundMemberTy)((void)0);
  assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI)((void)0);

  QualType fnType =
    op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType();

  const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>();
  QualType resultType = proto->getCallResultType(Context);
  ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType());

  // Check that the object type isn't more qualified than the
  // member function we're calling.
  Qualifiers funcQuals = proto->getMethodQuals();

  QualType objectType = op->getLHS()->getType();
  if (op->getOpcode() == BO_PtrMemI)
    objectType = objectType->castAs<PointerType>()->getPointeeType();
  Qualifiers objectQuals = objectType.getQualifiers();

  Qualifiers difference = objectQuals - funcQuals;
  difference.removeObjCGCAttr();
  difference.removeAddressSpace();
  if (difference) {
    std::string qualsString = difference.getAsString();
    Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
      << fnType.getUnqualifiedType()
      << qualsString
      << (qualsString.find(' ') == std::string::npos ? 1 : 2);
  }

  CXXMemberCallExpr *call = CXXMemberCallExpr::Create(
      Context, MemExprE, Args, resultType, valueKind, RParenLoc,
      CurFPFeatureOverrides(), proto->getNumParams());

  if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(),
                          call, nullptr))
    return ExprError();

  if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc))
    return ExprError();

  if (CheckOtherCall(call, proto))
    return ExprError();

  return MaybeBindToTemporary(call);
}

// We only try to build a recovery expr at this level if we can preserve
// the return type, otherwise we return ExprError() and let the caller
// recover.
auto BuildRecoveryExpr = [&](QualType Type) {
  if (!AllowRecovery)
    return ExprError();
  std::vector<Expr *> SubExprs = {MemExprE};
  llvm::for_each(Args, [&SubExprs](Expr *E) { SubExprs.push_back(E); });
  return CreateRecoveryExpr(MemExprE->getBeginLoc(), RParenLoc, SubExprs,
                            Type);
};
if (isa<CXXPseudoDestructorExpr>(NakedMemExpr))
  return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_PRValue,
                          RParenLoc, CurFPFeatureOverrides());

UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
  return ExprError();

MemberExpr *MemExpr;
CXXMethodDecl *Method = nullptr;
DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public);
NestedNameSpecifier *Qualifier = nullptr;
if (isa<MemberExpr>(NakedMemExpr)) {
  MemExpr = cast<MemberExpr>(NakedMemExpr);
  Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl());
  FoundDecl = MemExpr->getFoundDecl();
  Qualifier = MemExpr->getQualifier();
  UnbridgedCasts.restore();
} else {
  UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr);
  Qualifier = UnresExpr->getQualifier();

  QualType ObjectType = UnresExpr->getBaseType();
  Expr::Classification ObjectClassification
    = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue()
                          : UnresExpr->getBase()->Classify(Context);

  // Add overload candidates
  OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(),
                                    OverloadCandidateSet::CSK_Normal);

  // FIXME: avoid copy.
  TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
  if (UnresExpr->hasExplicitTemplateArgs()) {
    UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
    TemplateArgs = &TemplateArgsBuffer;
  }

  for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(),
         E = UnresExpr->decls_end(); I != E; ++I) {

    NamedDecl *Func = *I;
    CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext());
    if (isa<UsingShadowDecl>(Func))
      Func = cast<UsingShadowDecl>(Func)->getTargetDecl();


    // Microsoft supports direct constructor calls.
    if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) {
      AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), Args,
                           CandidateSet,
                           /*SuppressUserConversions*/ false);
    } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
      // If explicit template arguments were provided, we can't call a
      // non-template member function.
      if (TemplateArgs)
        continue;

      AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType,
                         ObjectClassification, Args, CandidateSet,
                         /*SuppressUserConversions=*/false);
    } else {
      AddMethodTemplateCandidate(
          cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC,
          TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet,
          /*SuppressUserConversions=*/false);
    }
  }

  DeclarationName DeclName = UnresExpr->getMemberName();

  UnbridgedCasts.restore();

  OverloadCandidateSet::iterator Best;
  bool Succeeded = false;
  switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(),
                                          Best)) {
  case OR_Success:
    Method = cast<CXXMethodDecl>(Best->Function);
    FoundDecl = Best->FoundDecl;
    CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
    if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
      break;
    // If FoundDecl is different from Method (such as if one is a template
    // and the other a specialization), make sure DiagnoseUseOfDecl is
    // called on both.
    // FIXME: This would be more comprehensively addressed by modifying
    // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
    // being used.
    if (Method != FoundDecl.getDecl() &&
                    DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
      break;
    Succeeded = true;
    break;

  case OR_No_Viable_Function:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(
            UnresExpr->getMemberLoc(),
            PDiag(diag::err_ovl_no_viable_member_function_in_call)
                << DeclName << MemExprE->getSourceRange()),
        *this, OCD_AllCandidates, Args);
    break;
  case OR_Ambiguous:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(UnresExpr->getMemberLoc(),
                            PDiag(diag::err_ovl_ambiguous_member_call)
                                << DeclName << MemExprE->getSourceRange()),
        *this, OCD_AmbiguousCandidates, Args);
    break;
  case OR_Deleted:
    CandidateSet.NoteCandidates(
        PartialDiagnosticAt(UnresExpr->getMemberLoc(),
                            PDiag(diag::err_ovl_deleted_member_call)
                                << DeclName << MemExprE->getSourceRange()),
        *this, OCD_AllCandidates, Args);
    break;
  }
  // Overload resolution fails, try to recover.
  if (!Succeeded)
    return BuildRecoveryExpr(chooseRecoveryType(CandidateSet, &Best));

  MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method);

  // If overload resolution picked a static member, build a
  // non-member call based on that function.
  if (Method->isStatic()) {
    return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args,
                                 RParenLoc);
  }

  MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens());
}

QualType ResultType = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultType);
ResultType = ResultType.getNonLValueExprType(Context);

assert(Method && "Member call to something that isn't a method?")((void)0);
const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
CXXMemberCallExpr *TheCall = CXXMemberCallExpr::Create(
    Context, MemExprE, Args, ResultType, VK, RParenLoc,
    CurFPFeatureOverrides(), Proto->getNumParams());

// Check for a valid return type.
if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(),
                        TheCall, Method))
  return BuildRecoveryExpr(ResultType);

// Convert the object argument (for a non-static member function call).
// We only need to do this if there was actually an overload; otherwise
// it was done at lookup.
if (!Method->isStatic()) {
  ExprResult ObjectArg =
    PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier,
                                        FoundDecl, Method);
  if (ObjectArg.isInvalid())
    return ExprError();
  MemExpr->setBase(ObjectArg.get());
}

// Convert the rest of the arguments
if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args,
                            RParenLoc))
  return BuildRecoveryExpr(ResultType);

DiagnoseSentinelCalls(Method, LParenLoc, Args);

if (CheckFunctionCall(Method, TheCall, Proto))
  return ExprError();

// In the case the method to call was not selected by the overloading
// resolution process, we still need to handle the enable_if attribute. Do
// that here, so it will not hide previous -- and more relevant -- errors.
if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) {
  if (const EnableIfAttr *Attr =
          CheckEnableIf(Method, LParenLoc, Args, true)) {
    Diag(MemE->getMemberLoc(),
         diag::err_ovl_no_viable_member_function_in_call)
        << Method << Method->getSourceRange();
    Diag(Method->getLocation(),
         diag::note_ovl_candidate_disabled_by_function_cond_attr)
        << Attr->getCond()->getSourceRange() << Attr->getMessage();
    return ExprError();
  }
}

if ((isa<CXXConstructorDecl>(CurContext) ||
     isa<CXXDestructorDecl>(CurContext)) &&
    TheCall->getMethodDecl()->isPure()) {
  const CXXMethodDecl *MD = TheCall->getMethodDecl();

  if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) &&
      MemExpr->performsVirtualDispatch(getLangOpts())) {
    Diag(MemExpr->getBeginLoc(),
         diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor)
        << MD->getDeclName() << isa<CXXDestructorDecl>(CurContext)
        << MD->getParent();

    Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName();
    if (getLangOpts().AppleKext)
      Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext)
          << MD->getParent() << MD->getDeclName();
  }
}

if (CXXDestructorDecl *DD =
        dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) {
  // a->A::f() doesn't go through the vtable, except in AppleKext mode.
  bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext;
  CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false,
                       CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true,
                       MemExpr->getMemberLoc());
}

return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall),
                                   TheCall->getMethodDecl());
14454}

14456/// BuildCallToObjectOfClassType - Build a call to an object of class
14457/// type (C++ [over.call.object]), which can end up invoking an
14458/// overloaded function call operator (@c operator()) or performing a
14459/// user-defined conversion on the object argument.
14460ExprResult
14461Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
                                 SourceLocation LParenLoc,
                                 MultiExprArg Args,
                                 SourceLocation RParenLoc) {
if (checkPlaceholderForOverload(*this, Obj))
  return ExprError();
ExprResult Object = Obj;

UnbridgedCastsSet UnbridgedCasts;
if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
  return ExprError();

assert(Object.get()->getType()->isRecordType() &&((void)0)
       "Requires object type argument")((void)0);

// C++ [over.call.object]p1:
//  If the primary-expression E in the function call syntax
//  evaluates to a class object of type "cv T", then the set of
//  candidate functions includes at least the function call
//  operators of T. The function call operators of T are obtained by
//  ordinary lookup of the name operator() in the context of
//  (E).operator().
OverloadCandidateSet CandidateSet(LParenLoc,
                                  OverloadCandidateSet::CSK_Operator);
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call);

if (RequireCompleteType(LParenLoc, Object.get()->getType(),
                        diag::err_incomplete_object_call, Object.get()))
  return true;

const auto *Record = Object.get()->getType()->castAs<RecordType>();
LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName);
LookupQualifiedName(R, Record->getDecl());
R.suppressDiagnostics();

for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
     Oper != OperEnd; ++Oper) {
  AddMethodCandidate(Oper.getPair(), Object.get()->getType(),
                     Object.get()->Classify(Context), Args, CandidateSet,
                     /*SuppressUserConversion=*/false);
}

// C++ [over.call.object]p2:
//   In addition, for each (non-explicit in C++0x) conversion function
//   declared in T of the form
//
//        operator conversion-type-id () cv-qualifier;
//
//   where cv-qualifier is the same cv-qualification as, or a
//   greater cv-qualification than, cv, and where conversion-type-id
//   denotes the type "pointer to function of (P1,...,Pn) returning
//   R", or the type "reference to pointer to function of
//   (P1,...,Pn) returning R", or the type "reference to function
//   of (P1,...,Pn) returning R", a surrogate call function [...]
//   is also considered as a candidate function. Similarly,
//   surrogate call functions are added to the set of candidate
//   functions for each conversion function declared in an
//   accessible base class provided the function is not hidden
//   within T by another intervening declaration.
const auto &Conversions =
    cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
  NamedDecl *D = *I;
  CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
  if (isa<UsingShadowDecl>(D))
    D = cast<UsingShadowDecl>(D)->getTargetDecl();

  // Skip over templated conversion functions; they aren't
  // surrogates.
  if (isa<FunctionTemplateDecl>(D))
    continue;

  CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
  if (!Conv->isExplicit()) {
    // Strip the reference type (if any) and then the pointer type (if
    // any) to get down to what might be a function type.
    QualType ConvType = Conv->getConversionType().getNonReferenceType();
    if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
      ConvType = ConvPtrType->getPointeeType();

    if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>())
    {
      AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto,
                            Object.get(), Args, CandidateSet);
    }
  }
}

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(),
                                        Best)) {
case OR_Success:
  // Overload resolution succeeded; we'll build the appropriate call
  // below.
  break;

case OR_No_Viable_Function: {
  PartialDiagnostic PD =
      CandidateSet.empty()
          ? (PDiag(diag::err_ovl_no_oper)
             << Object.get()->getType() << /*call*/ 1
             << Object.get()->getSourceRange())
          : (PDiag(diag::err_ovl_no_viable_object_call)
             << Object.get()->getType() << Object.get()->getSourceRange());
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(Object.get()->getBeginLoc(), PD), *this,
      OCD_AllCandidates, Args);
  break;
}
case OR_Ambiguous:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(Object.get()->getBeginLoc(),
                          PDiag(diag::err_ovl_ambiguous_object_call)
                              << Object.get()->getType()
                              << Object.get()->getSourceRange()),
      *this, OCD_AmbiguousCandidates, Args);
  break;

case OR_Deleted:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(Object.get()->getBeginLoc(),
                          PDiag(diag::err_ovl_deleted_object_call)
                              << Object.get()->getType()
                              << Object.get()->getSourceRange()),
      *this, OCD_AllCandidates, Args);
  break;
}

if (Best == CandidateSet.end())
  return true;

UnbridgedCasts.restore();

if (Best->Function == nullptr) {
  // Since there is no function declaration, this is one of the
  // surrogate candidates. Dig out the conversion function.
  CXXConversionDecl *Conv
    = cast<CXXConversionDecl>(
                       Best->Conversions[0].UserDefined.ConversionFunction);

  CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr,
                            Best->FoundDecl);
  if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
    return ExprError();
  assert(Conv == Best->FoundDecl.getDecl() &&((void)0)
           "Found Decl & conversion-to-functionptr should be same, right?!")((void)0);
  // We selected one of the surrogate functions that converts the
  // object parameter to a function pointer. Perform the conversion
  // on the object argument, then let BuildCallExpr finish the job.

  // Create an implicit member expr to refer to the conversion operator.
  // and then call it.
  ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl,
                                           Conv, HadMultipleCandidates);
  if (Call.isInvalid())
    return ExprError();
  // Record usage of conversion in an implicit cast.
  Call = ImplicitCastExpr::Create(
      Context, Call.get()->getType(), CK_UserDefinedConversion, Call.get(),
      nullptr, VK_PRValue, CurFPFeatureOverrides());

  return BuildCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc);
}

CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl);

// We found an overloaded operator(). Build a CXXOperatorCallExpr
// that calls this method, using Object for the implicit object
// parameter and passing along the remaining arguments.
CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);

// An error diagnostic has already been printed when parsing the declaration.
if (Method->isInvalidDecl())
  return ExprError();

const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
unsigned NumParams = Proto->getNumParams();

DeclarationNameInfo OpLocInfo(
             Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc);
OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc));
ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
                                         Obj, HadMultipleCandidates,
                                         OpLocInfo.getLoc(),
                                         OpLocInfo.getInfo());
if (NewFn.isInvalid())
  return true;

// The number of argument slots to allocate in the call. If we have default
// arguments we need to allocate space for them as well. We additionally
// need one more slot for the object parameter.
unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams);

// Build the full argument list for the method call (the implicit object
// parameter is placed at the beginning of the list).
SmallVector<Expr *, 8> MethodArgs(NumArgsSlots);

bool IsError = false;

// Initialize the implicit object parameter.
ExprResult ObjRes =
  PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr,
                                      Best->FoundDecl, Method);
if (ObjRes.isInvalid())
  IsError = true;
else
  Object = ObjRes;
MethodArgs[0] = Object.get();

// Check the argument types.
for (unsigned i = 0; i != NumParams; i++) {
  Expr *Arg;
  if (i < Args.size()) {
    Arg = Args[i];

    // Pass the argument.

    ExprResult InputInit
      = PerformCopyInitialization(InitializedEntity::InitializeParameter(
                                                  Context,
                                                  Method->getParamDecl(i)),
                                  SourceLocation(), Arg);

    IsError |= InputInit.isInvalid();
    Arg = InputInit.getAs<Expr>();
  } else {
    ExprResult DefArg
      = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i));
    if (DefArg.isInvalid()) {
      IsError = true;
      break;
    }

    Arg = DefArg.getAs<Expr>();
  }

  MethodArgs[i + 1] = Arg;
}

// If this is a variadic call, handle args passed through "...".
if (Proto->isVariadic()) {
  // Promote the arguments (C99 6.5.2.2p7).
  for (unsigned i = NumParams, e = Args.size(); i < e; i++) {
    ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
                                                      nullptr);
    IsError |= Arg.isInvalid();
    MethodArgs[i + 1] = Arg.get();
  }
}

if (IsError)
  return true;

DiagnoseSentinelCalls(Method, LParenLoc, Args);

// Once we've built TheCall, all of the expressions are properly owned.
QualType ResultTy = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);

CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
    Context, OO_Call, NewFn.get(), MethodArgs, ResultTy, VK, RParenLoc,
    CurFPFeatureOverrides());

if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method))
  return true;

if (CheckFunctionCall(Method, TheCall, Proto))
  return true;

return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
14735}

14737/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
14738///  (if one exists), where @c Base is an expression of class type and
14739/// @c Member is the name of the member we're trying to find.
14740ExprResult
14741Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
                             bool *NoArrowOperatorFound) {
assert(Base->getType()->isRecordType() &&((void)0)
       "left-hand side must have class type")((void)0);

if (checkPlaceholderForOverload(*this, Base))
  return ExprError();

SourceLocation Loc = Base->getExprLoc();

// C++ [over.ref]p1:
//
//   [...] An expression x->m is interpreted as (x.operator->())->m
//   for a class object x of type T if T::operator->() exists and if
//   the operator is selected as the best match function by the
//   overload resolution mechanism (13.3).
DeclarationName OpName =
  Context.DeclarationNames.getCXXOperatorName(OO_Arrow);
OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator);

if (RequireCompleteType(Loc, Base->getType(),
                        diag::err_typecheck_incomplete_tag, Base))
  return ExprError();

LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
LookupQualifiedName(R, Base->getType()->castAs<RecordType>()->getDecl());
R.suppressDiagnostics();

for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
     Oper != OperEnd; ++Oper) {
  AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context),
                     None, CandidateSet, /*SuppressUserConversion=*/false);
}

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
case OR_Success:
  // Overload resolution succeeded; we'll build the call below.
  break;

case OR_No_Viable_Function: {
  auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Base);
  if (CandidateSet.empty()) {
    QualType BaseType = Base->getType();
    if (NoArrowOperatorFound) {
      // Report this specific error to the caller instead of emitting a
      // diagnostic, as requested.
      *NoArrowOperatorFound = true;
      return ExprError();
    }
    Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
      << BaseType << Base->getSourceRange();
    if (BaseType->isRecordType() && !BaseType->isPointerType()) {
      Diag(OpLoc, diag::note_typecheck_member_reference_suggestion)
        << FixItHint::CreateReplacement(OpLoc, ".");
    }
  } else
    Diag(OpLoc, diag::err_ovl_no_viable_oper)
      << "operator->" << Base->getSourceRange();
  CandidateSet.NoteCandidates(*this, Base, Cands);
  return ExprError();
}
case OR_Ambiguous:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary)
                                     << "->" << Base->getType()
                                     << Base->getSourceRange()),
      *this, OCD_AmbiguousCandidates, Base);
  return ExprError();

case OR_Deleted:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
                                     << "->" << Base->getSourceRange()),
      *this, OCD_AllCandidates, Base);
  return ExprError();
}

CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl);

// Convert the object parameter.
CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
ExprResult BaseResult =
  PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr,
                                      Best->FoundDecl, Method);
if (BaseResult.isInvalid())
  return ExprError();
Base = BaseResult.get();

// Build the operator call.
ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
                                          Base, HadMultipleCandidates, OpLoc);
if (FnExpr.isInvalid())
  return ExprError();

QualType ResultTy = Method->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);
CXXOperatorCallExpr *TheCall =
    CXXOperatorCallExpr::Create(Context, OO_Arrow, FnExpr.get(), Base,
                                ResultTy, VK, OpLoc, CurFPFeatureOverrides());

if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method))
  return ExprError();

if (CheckFunctionCall(Method, TheCall,
                      Method->getType()->castAs<FunctionProtoType>()))
  return ExprError();

return MaybeBindToTemporary(TheCall);
14854}

14856/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to
14857/// a literal operator described by the provided lookup results.
14858ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R,
                                        DeclarationNameInfo &SuffixInfo,
                                        ArrayRef<Expr*> Args,
                                        SourceLocation LitEndLoc,
                                     TemplateArgumentListInfo *TemplateArgs) {
SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc();

OverloadCandidateSet CandidateSet(UDSuffixLoc,
                                  OverloadCandidateSet::CSK_Normal);
AddNonMemberOperatorCandidates(R.asUnresolvedSet(), Args, CandidateSet,
                               TemplateArgs);

bool HadMultipleCandidates = (CandidateSet.size() > 1);

// Perform overload resolution. This will usually be trivial, but might need
// to perform substitutions for a literal operator template.
OverloadCandidateSet::iterator Best;
switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) {
case OR_Success:
case OR_Deleted:
  break;

case OR_No_Viable_Function:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(UDSuffixLoc,
                          PDiag(diag::err_ovl_no_viable_function_in_call)
                              << R.getLookupName()),
      *this, OCD_AllCandidates, Args);
  return ExprError();

case OR_Ambiguous:
  CandidateSet.NoteCandidates(
      PartialDiagnosticAt(R.getNameLoc(), PDiag(diag::err_ovl_ambiguous_call)
                                              << R.getLookupName()),
      *this, OCD_AmbiguousCandidates, Args);
  return ExprError();
}

FunctionDecl *FD = Best->Function;
ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl,
                                      nullptr, HadMultipleCandidates,
                                      SuffixInfo.getLoc(),
                                      SuffixInfo.getInfo());
if (Fn.isInvalid())
  return true;

// Check the argument types. This should almost always be a no-op, except
// that array-to-pointer decay is applied to string literals.
Expr *ConvArgs[2];
for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
  ExprResult InputInit = PerformCopyInitialization(
    InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)),
    SourceLocation(), Args[ArgIdx]);
  if (InputInit.isInvalid())
    return true;
  ConvArgs[ArgIdx] = InputInit.get();
}

QualType ResultTy = FD->getReturnType();
ExprValueKind VK = Expr::getValueKindForType(ResultTy);
ResultTy = ResultTy.getNonLValueExprType(Context);

UserDefinedLiteral *UDL = UserDefinedLiteral::Create(
    Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy,
    VK, LitEndLoc, UDSuffixLoc, CurFPFeatureOverrides());

if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD))
  return ExprError();

if (CheckFunctionCall(FD, UDL, nullptr))
  return ExprError();

return CheckForImmediateInvocation(MaybeBindToTemporary(UDL), FD);
14931}

14933/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
14934/// given LookupResult is non-empty, it is assumed to describe a member which
14935/// will be invoked. Otherwise, the function will be found via argument
14936/// dependent lookup.
14937/// CallExpr is set to a valid expression and FRS_Success returned on success,
14938/// otherwise CallExpr is set to ExprError() and some non-success value
14939/// is returned.
14940Sema::ForRangeStatus
14941Sema::BuildForRangeBeginEndCall(SourceLocation Loc,
                              SourceLocation RangeLoc,
                              const DeclarationNameInfo &NameInfo,
                              LookupResult &MemberLookup,
                              OverloadCandidateSet *CandidateSet,
                              Expr *Range, ExprResult *CallExpr) {
Scope *S = nullptr;

CandidateSet->clear(OverloadCandidateSet::CSK_Normal);
if (!MemberLookup.empty()) {
1
Assuming the condition is false→
2
←
Taking false branch→
  ExprResult MemberRef =
      BuildMemberReferenceExpr(Range, Range->getType(), Loc,
                               /*IsPtr=*/false, CXXScopeSpec(),
                               /*TemplateKWLoc=*/SourceLocation(),
                               /*FirstQualifierInScope=*/nullptr,
                               MemberLookup,
                               /*TemplateArgs=*/nullptr, S);
  if (MemberRef.isInvalid()) {
    *CallExpr = ExprError();
    return FRS_DiagnosticIssued;
  }
  *CallExpr = BuildCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr);
  if (CallExpr->isInvalid()) {
    *CallExpr = ExprError();
    return FRS_DiagnosticIssued;
  }
} else {
  ExprResult FnR = CreateUnresolvedLookupExpr(/*NamingClass=*/nullptr,
                                              NestedNameSpecifierLoc(),
                                              NameInfo, UnresolvedSet<0>());
  if (FnR.isInvalid())
3
←
Assuming the condition is false→
4
←
Taking false branch→
    return FRS_DiagnosticIssued;
  UnresolvedLookupExpr *Fn = cast<UnresolvedLookupExpr>(FnR.get());
5
←
The object is a 'UnresolvedLookupExpr'→

  bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc,
6
←
Calling 'Sema::buildOverloadedCallSet'→
                                                  CandidateSet, CallExpr);
  if (CandidateSet->empty() || CandidateSetError) {
    *CallExpr = ExprError();
    return FRS_NoViableFunction;
  }
  OverloadCandidateSet::iterator Best;
  OverloadingResult OverloadResult =
      CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best);

  if (OverloadResult == OR_No_Viable_Function) {
    *CallExpr = ExprError();
    return FRS_NoViableFunction;
  }
  *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range,
                                       Loc, nullptr, CandidateSet, &Best,
                                       OverloadResult,
                                       /*AllowTypoCorrection=*/false);
  if (CallExpr->isInvalid() || OverloadResult != OR_Success) {
    *CallExpr = ExprError();
    return FRS_DiagnosticIssued;
  }
}
return FRS_Success;
14999}


15002/// FixOverloadedFunctionReference - E is an expression that refers to
15003/// a C++ overloaded function (possibly with some parentheses and
15004/// perhaps a '&' around it). We have resolved the overloaded function
15005/// to the function declaration Fn, so patch up the expression E to
15006/// refer (possibly indirectly) to Fn. Returns the new expr.
15007Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found,
                                         FunctionDecl *Fn) {
if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
  Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(),
                                                 Found, Fn);
  if (SubExpr == PE->getSubExpr())
    return PE;

  return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr);
}

if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
  Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(),
                                                 Found, Fn);
  assert(Context.hasSameType(ICE->getSubExpr()->getType(),((void)0)
                             SubExpr->getType()) &&((void)0)
         "Implicit cast type cannot be determined from overload")((void)0);
  assert(ICE->path_empty() && "fixing up hierarchy conversion?")((void)0);
  if (SubExpr == ICE->getSubExpr())
    return ICE;

  return ImplicitCastExpr::Create(Context, ICE->getType(), ICE->getCastKind(),
                                  SubExpr, nullptr, ICE->getValueKind(),
                                  CurFPFeatureOverrides());
}

if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
  if (!GSE->isResultDependent()) {
    Expr *SubExpr =
        FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn);
    if (SubExpr == GSE->getResultExpr())
      return GSE;

    // Replace the resulting type information before rebuilding the generic
    // selection expression.
    ArrayRef<Expr *> A = GSE->getAssocExprs();
    SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end());
    unsigned ResultIdx = GSE->getResultIndex();
    AssocExprs[ResultIdx] = SubExpr;

    return GenericSelectionExpr::Create(
        Context, GSE->getGenericLoc(), GSE->getControllingExpr(),
        GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(),
        GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(),
        ResultIdx);
  }
  // Rather than fall through to the unreachable, return the original generic
  // selection expression.
  return GSE;
}

if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) {
  assert(UnOp->getOpcode() == UO_AddrOf &&((void)0)
         "Can only take the address of an overloaded function")((void)0);
  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
    if (Method->isStatic()) {
      // Do nothing: static member functions aren't any different
      // from non-member functions.
    } else {
      // Fix the subexpression, which really has to be an
      // UnresolvedLookupExpr holding an overloaded member function
      // or template.
      Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
                                                     Found, Fn);
      if (SubExpr == UnOp->getSubExpr())
        return UnOp;

      assert(isa<DeclRefExpr>(SubExpr)((void)0)
             && "fixed to something other than a decl ref")((void)0);
      assert(cast<DeclRefExpr>(SubExpr)->getQualifier()((void)0)
             && "fixed to a member ref with no nested name qualifier")((void)0);

      // We have taken the address of a pointer to member
      // function. Perform the computation here so that we get the
      // appropriate pointer to member type.
      QualType ClassType
        = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
      QualType MemPtrType
        = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr());
      // Under the MS ABI, lock down the inheritance model now.
      if (Context.getTargetInfo().getCXXABI().isMicrosoft())
        (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType);

      return UnaryOperator::Create(
          Context, SubExpr, UO_AddrOf, MemPtrType, VK_PRValue, OK_Ordinary,
          UnOp->getOperatorLoc(), false, CurFPFeatureOverrides());
    }
  }
  Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
                                                 Found, Fn);
  if (SubExpr == UnOp->getSubExpr())
    return UnOp;

  return UnaryOperator::Create(
      Context, SubExpr, UO_AddrOf, Context.getPointerType(SubExpr->getType()),
      VK_PRValue, OK_Ordinary, UnOp->getOperatorLoc(), false,
      CurFPFeatureOverrides());
}

if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
  // FIXME: avoid copy.
  TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
  if (ULE->hasExplicitTemplateArgs()) {
    ULE->copyTemplateArgumentsInto(TemplateArgsBuffer);
    TemplateArgs = &TemplateArgsBuffer;
  }

  DeclRefExpr *DRE =
      BuildDeclRefExpr(Fn, Fn->getType(), VK_LValue, ULE->getNameInfo(),
                       ULE->getQualifierLoc(), Found.getDecl(),
                       ULE->getTemplateKeywordLoc(), TemplateArgs);
  DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1);
  return DRE;
}

if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) {
  // FIXME: avoid copy.
  TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
  if (MemExpr->hasExplicitTemplateArgs()) {
    MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
    TemplateArgs = &TemplateArgsBuffer;
  }

  Expr *Base;

  // If we're filling in a static method where we used to have an
  // implicit member access, rewrite to a simple decl ref.
  if (MemExpr->isImplicitAccess()) {
    if (cast<CXXMethodDecl>(Fn)->isStatic()) {
      DeclRefExpr *DRE = BuildDeclRefExpr(
          Fn, Fn->getType(), VK_LValue, MemExpr->getNameInfo(),
          MemExpr->getQualifierLoc(), Found.getDecl(),
          MemExpr->getTemplateKeywordLoc(), TemplateArgs);
      DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1);
      return DRE;
    } else {
      SourceLocation Loc = MemExpr->getMemberLoc();
      if (MemExpr->getQualifier())
        Loc = MemExpr->getQualifierLoc().getBeginLoc();
      Base =
          BuildCXXThisExpr(Loc, MemExpr->getBaseType(), /*IsImplicit=*/true);
    }
  } else
    Base = MemExpr->getBase();

  ExprValueKind valueKind;
  QualType type;
  if (cast<CXXMethodDecl>(Fn)->isStatic()) {
    valueKind = VK_LValue;
    type = Fn->getType();
  } else {
    valueKind = VK_PRValue;
    type = Context.BoundMemberTy;
  }

  return BuildMemberExpr(
      Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(),
      MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found,
      /*HadMultipleCandidates=*/true, MemExpr->getMemberNameInfo(),
      type, valueKind, OK_Ordinary, TemplateArgs);
}

llvm_unreachable("Invalid reference to overloaded function")__builtin_unreachable();
15170}

15172ExprResult Sema::FixOverloadedFunctionReference(ExprResult E,
                                              DeclAccessPair Found,
                                              FunctionDecl *Fn) {
return FixOverloadedFunctionReference(E.get(), Found, Fn);
15176}

←

/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include/llvm/ADT/SmallVector.h

→

1//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the SmallVector class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_ADT_SMALLVECTOR_H
14#define LLVM_ADT_SMALLVECTOR_H

16#include "llvm/ADT/iterator_range.h"
17#include "llvm/Support/Compiler.h"
18#include "llvm/Support/ErrorHandling.h"
19#include "llvm/Support/MemAlloc.h"
20#include "llvm/Support/type_traits.h"
21#include <algorithm>
22#include <cassert>
23#include <cstddef>
24#include <cstdlib>
25#include <cstring>
26#include <functional>
27#include <initializer_list>
28#include <iterator>
29#include <limits>
30#include <memory>
31#include <new>
32#include <type_traits>
33#include <utility>

35namespace llvm {

37/// This is all the stuff common to all SmallVectors.
38///
39/// The template parameter specifies the type which should be used to hold the
40/// Size and Capacity of the SmallVector, so it can be adjusted.
41/// Using 32 bit size is desirable to shrink the size of the SmallVector.
42/// Using 64 bit size is desirable for cases like SmallVector<char>, where a
43/// 32 bit size would limit the vector to ~4GB. SmallVectors are used for
44/// buffering bitcode output - which can exceed 4GB.
45template <class Size_T> class SmallVectorBase {
46protected:
void *BeginX;
Size_T Size = 0, Capacity;

/// The maximum value of the Size_T used.
static constexpr size_t SizeTypeMax() {
  return std::numeric_limits<Size_T>::max();
}

SmallVectorBase() = delete;
SmallVectorBase(void *FirstEl, size_t TotalCapacity)
    : BeginX(FirstEl), Capacity(TotalCapacity) {}

/// This is a helper for \a grow() that's out of line to reduce code
/// duplication.  This function will report a fatal error if it can't grow at
/// least to \p MinSize.
void *mallocForGrow(size_t MinSize, size_t TSize, size_t &NewCapacity);

/// This is an implementation of the grow() method which only works
/// on POD-like data types and is out of line to reduce code duplication.
/// This function will report a fatal error if it cannot increase capacity.
void grow_pod(void *FirstEl, size_t MinSize, size_t TSize);

69public:
size_t size() const { return Size; }
size_t capacity() const { return Capacity; }

LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { return !Size; }
26
←
Assuming field 'Size' is not equal to 0→
27
←
Returning zero, which participates in a condition later→

/// Set the array size to \p N, which the current array must have enough
/// capacity for.
///
/// This does not construct or destroy any elements in the vector.
///
/// Clients can use this in conjunction with capacity() to write past the end
/// of the buffer when they know that more elements are available, and only
/// update the size later. This avoids the cost of value initializing elements
/// which will only be overwritten.
void set_size(size_t N) {
  assert(N <= capacity())((void)0);
  Size = N;
}
88};

90template <class T>
91using SmallVectorSizeType =
  typename std::conditional<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t,
                            uint32_t>::type;

95/// Figure out the offset of the first element.
96template <class T, typename = void> struct SmallVectorAlignmentAndSize {
alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof(
    SmallVectorBase<SmallVectorSizeType<T>>)];
alignas(T) char FirstEl[sizeof(T)];
100};

102/// This is the part of SmallVectorTemplateBase which does not depend on whether
103/// the type T is a POD. The extra dummy template argument is used by ArrayRef
104/// to avoid unnecessarily requiring T to be complete.
105template <typename T, typename = void>
106class SmallVectorTemplateCommon
  : public SmallVectorBase<SmallVectorSizeType<T>> {
using Base = SmallVectorBase<SmallVectorSizeType<T>>;

/// Find the address of the first element.  For this pointer math to be valid
/// with small-size of 0 for T with lots of alignment, it's important that
/// SmallVectorStorage is properly-aligned even for small-size of 0.
void *getFirstEl() const {
  return const_cast<void *>(reinterpret_cast<const void *>(
      reinterpret_cast<const char *>(this) +
      offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)__builtin_offsetof(SmallVectorAlignmentAndSize<T>, FirstEl
)));
}
// Space after 'FirstEl' is clobbered, do not add any instance vars after it.

120protected:
SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}

void grow_pod(size_t MinSize, size_t TSize) {
  Base::grow_pod(getFirstEl(), MinSize, TSize);
}

/// Return true if this is a smallvector which has not had dynamic
/// memory allocated for it.
bool isSmall() const { return this->BeginX == getFirstEl(); }

/// Put this vector in a state of being small.
void resetToSmall() {
  this->BeginX = getFirstEl();
  this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
}

/// Return true if V is an internal reference to the given range.
bool isReferenceToRange(const void *V, const void *First, const void *Last) const {
  // Use std::less to avoid UB.
  std::less<> LessThan;
  return !LessThan(V, First) && LessThan(V, Last);
}

/// Return true if V is an internal reference to this vector.
bool isReferenceToStorage(const void *V) const {
  return isReferenceToRange(V, this->begin(), this->end());
}

/// Return true if First and Last form a valid (possibly empty) range in this
/// vector's storage.
bool isRangeInStorage(const void *First, const void *Last) const {
  // Use std::less to avoid UB.
  std::less<> LessThan;
  return !LessThan(First, this->begin()) && !LessThan(Last, First) &&
         !LessThan(this->end(), Last);
}

/// Return true unless Elt will be invalidated by resizing the vector to
/// NewSize.
bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
  // Past the end.
  if (LLVM_LIKELY(!isReferenceToStorage(Elt))__builtin_expect((bool)(!isReferenceToStorage(Elt)), true))
    return true;

  // Return false if Elt will be destroyed by shrinking.
  if (NewSize <= this->size())
    return Elt < this->begin() + NewSize;

  // Return false if we need to grow.
  return NewSize <= this->capacity();
}

/// Check whether Elt will be invalidated by resizing the vector to NewSize.
void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
  assert(isSafeToReferenceAfterResize(Elt, NewSize) &&((void)0)
         "Attempting to reference an element of the vector in an operation "((void)0)
         "that invalidates it")((void)0);
}

/// Check whether Elt will be invalidated by increasing the size of the
/// vector by N.
void assertSafeToAdd(const void *Elt, size_t N = 1) {
  this->assertSafeToReferenceAfterResize(Elt, this->size() + N);
}

/// Check whether any part of the range will be invalidated by clearing.
void assertSafeToReferenceAfterClear(const T *From, const T *To) {
  if (From == To)
    return;
  this->assertSafeToReferenceAfterResize(From, 0);
  this->assertSafeToReferenceAfterResize(To - 1, 0);
}
template <
    class ItTy,
    std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
                     bool> = false>
void assertSafeToReferenceAfterClear(ItTy, ItTy) {}

/// Check whether any part of the range will be invalidated by growing.
void assertSafeToAddRange(const T *From, const T *To) {
  if (From == To)
    return;
  this->assertSafeToAdd(From, To - From);
  this->assertSafeToAdd(To - 1, To - From);
}
template <
    class ItTy,
    std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
                     bool> = false>
void assertSafeToAddRange(ItTy, ItTy) {}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
template <class U>
static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt,
                                                 size_t N) {
  size_t NewSize = This->size() + N;
  if (LLVM_LIKELY(NewSize <= This->capacity())__builtin_expect((bool)(NewSize <= This->capacity()), true
))
    return &Elt;

  bool ReferencesStorage = false;
  int64_t Index = -1;
  if (!U::TakesParamByValue) {
    if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))__builtin_expect((bool)(This->isReferenceToStorage(&Elt
)), false)) {
      ReferencesStorage = true;
      Index = &Elt - This->begin();
    }
  }
  This->grow(NewSize);
  return ReferencesStorage ? This->begin() + Index : &Elt;
}

233public:
using size_type = size_t;
using difference_type = ptrdiff_t;
using value_type = T;
using iterator = T *;
using const_iterator = const T *;

using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;

using reference = T &;
using const_reference = const T &;
using pointer = T *;
using const_pointer = const T *;

using Base::capacity;
using Base::empty;
using Base::size;

// forward iterator creation methods.
iterator begin() { return (iterator)this->BeginX; }
const_iterator begin() const { return (const_iterator)this->BeginX; }
iterator end() { return begin() + size(); }
const_iterator end() const { return begin() + size(); }

// reverse iterator creation methods.
reverse_iterator rbegin()            { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
reverse_iterator rend()              { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin());}

size_type size_in_bytes() const { return size() * sizeof(T); }
size_type max_size() const {
  return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
}

size_t capacity_in_bytes() const { return capacity() * sizeof(T); }

/// Return a pointer to the vector's buffer, even if empty().
pointer data() { return pointer(begin()); }
/// Return a pointer to the vector's buffer, even if empty().
const_pointer data() const { return const_pointer(begin()); }

reference operator[](size_type idx) {
  assert(idx < size())((void)0);
  return begin()[idx];
}
const_reference operator[](size_type idx) const {
  assert(idx < size())((void)0);
  return begin()[idx];
}

reference front() {
  assert(!empty())((void)0);
  return begin()[0];
}
const_reference front() const {
  assert(!empty())((void)0);
  return begin()[0];
}

reference back() {
  assert(!empty())((void)0);
  return end()[-1];
}
const_reference back() const {
  assert(!empty())((void)0);
  return end()[-1];
}
302};

304/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put
305/// method implementations that are designed to work with non-trivial T's.
306///
307/// We approximate is_trivially_copyable with trivial move/copy construction and
308/// trivial destruction. While the standard doesn't specify that you're allowed
309/// copy these types with memcpy, there is no way for the type to observe this.
310/// This catches the important case of std::pair<POD, POD>, which is not
311/// trivially assignable.
312template <typename T, bool = (is_trivially_copy_constructible<T>::value) &&
                           (is_trivially_move_constructible<T>::value) &&
                           std::is_trivially_destructible<T>::value>
315class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
friend class SmallVectorTemplateCommon<T>;

318protected:
static constexpr bool TakesParamByValue = false;
using ValueParamT = const T &;

SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

static void destroy_range(T *S, T *E) {
  while (S != E) {
    --E;
    E->~T();
  }
}

/// Move the range [I, E) into the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(std::make_move_iterator(I),
                          std::make_move_iterator(E), Dest);
}

/// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(I, E, Dest);
}

/// Grow the allocated memory (without initializing new elements), doubling
/// the size of the allocated memory. Guarantees space for at least one more
/// element, or MinSize more elements if specified.
void grow(size_t MinSize = 0);

/// Create a new allocation big enough for \p MinSize and pass back its size
/// in \p NewCapacity. This is the first section of \a grow().
T *mallocForGrow(size_t MinSize, size_t &NewCapacity) {
  return static_cast<T *>(
      SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow(
          MinSize, sizeof(T), NewCapacity));
}

/// Move existing elements over to the new allocation \p NewElts, the middle
/// section of \a grow().
void moveElementsForGrow(T *NewElts);

/// Transfer ownership of the allocation, finishing up \a grow().
void takeAllocationForGrow(T *NewElts, size_t NewCapacity);

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
  return this->reserveForParamAndGetAddressImpl(this, Elt, N);
}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
  return const_cast<T *>(
      this->reserveForParamAndGetAddressImpl(this, Elt, N));
}

static T &&forward_value_param(T &&V) { return std::move(V); }
static const T &forward_value_param(const T &V) { return V; }

void growAndAssign(size_t NumElts, const T &Elt) {
  // Grow manually in case Elt is an internal reference.
  size_t NewCapacity;
  T *NewElts = mallocForGrow(NumElts, NewCapacity);
  std::uninitialized_fill_n(NewElts, NumElts, Elt);
  this->destroy_range(this->begin(), this->end());
  takeAllocationForGrow(NewElts, NewCapacity);
  this->set_size(NumElts);
}

template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
  // Grow manually in case one of Args is an internal reference.
  size_t NewCapacity;
  T *NewElts = mallocForGrow(0, NewCapacity);
  ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...);
  moveElementsForGrow(NewElts);
  takeAllocationForGrow(NewElts, NewCapacity);
  this->set_size(this->size() + 1);
  return this->back();
}

403public:
void push_back(const T &Elt) {
  const T *EltPtr = reserveForParamAndGetAddress(Elt);
  ::new ((void *)this->end()) T(*EltPtr);
  this->set_size(this->size() + 1);
}

void push_back(T &&Elt) {
  T *EltPtr = reserveForParamAndGetAddress(Elt);
  ::new ((void *)this->end()) T(::std::move(*EltPtr));
  this->set_size(this->size() + 1);
}

void pop_back() {
  this->set_size(this->size() - 1);
  this->end()->~T();
}
420};

422// Define this out-of-line to dissuade the C++ compiler from inlining it.
423template <typename T, bool TriviallyCopyable>
424void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
size_t NewCapacity;
T *NewElts = mallocForGrow(MinSize, NewCapacity);
moveElementsForGrow(NewElts);
takeAllocationForGrow(NewElts, NewCapacity);
429}

431// Define this out-of-line to dissuade the C++ compiler from inlining it.
432template <typename T, bool TriviallyCopyable>
433void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow(
  T *NewElts) {
// Move the elements over.
this->uninitialized_move(this->begin(), this->end(), NewElts);

// Destroy the original elements.
destroy_range(this->begin(), this->end());
440}

442// Define this out-of-line to dissuade the C++ compiler from inlining it.
443template <typename T, bool TriviallyCopyable>
444void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow(
  T *NewElts, size_t NewCapacity) {
// If this wasn't grown from the inline copy, deallocate the old space.
if (!this->isSmall())
  free(this->begin());

this->BeginX = NewElts;
this->Capacity = NewCapacity;
452}

454/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
455/// method implementations that are designed to work with trivially copyable
456/// T's. This allows using memcpy in place of copy/move construction and
457/// skipping destruction.
458template <typename T>
459class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
friend class SmallVectorTemplateCommon<T>;

462protected:
/// True if it's cheap enough to take parameters by value. Doing so avoids
/// overhead related to mitigations for reference invalidation.
static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *);

/// Either const T& or T, depending on whether it's cheap enough to take
/// parameters by value.
using ValueParamT =
    typename std::conditional<TakesParamByValue, T, const T &>::type;

SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

// No need to do a destroy loop for POD's.
static void destroy_range(T *, T *) {}

/// Move the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  // Just do a copy.
  uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  // Arbitrary iterator types; just use the basic implementation.
  std::uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template <typename T1, typename T2>
static void uninitialized_copy(
    T1 *I, T1 *E, T2 *Dest,
    std::enable_if_t<std::is_same<typename std::remove_const<T1>::type,
                                  T2>::value> * = nullptr) {
  // Use memcpy for PODs iterated by pointers (which includes SmallVector
  // iterators): std::uninitialized_copy optimizes to memmove, but we can
  // use memcpy here. Note that I and E are iterators and thus might be
  // invalid for memcpy if they are equal.
  if (I != E)
    memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
}

/// Double the size of the allocated memory, guaranteeing space for at
/// least one more element or MinSize if specified.
void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
  return this->reserveForParamAndGetAddressImpl(this, Elt, N);
}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
  return const_cast<T *>(
      this->reserveForParamAndGetAddressImpl(this, Elt, N));
}

/// Copy \p V or return a reference, depending on \a ValueParamT.
static ValueParamT forward_value_param(ValueParamT V) { return V; }

void growAndAssign(size_t NumElts, T Elt) {
  // Elt has been copied in case it's an internal reference, side-stepping
  // reference invalidation problems without losing the realloc optimization.
  this->set_size(0);
  this->grow(NumElts);
  std::uninitialized_fill_n(this->begin(), NumElts, Elt);
  this->set_size(NumElts);
}

template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
  // Use push_back with a copy in case Args has an internal reference,
  // side-stepping reference invalidation problems without losing the realloc
  // optimization.
  push_back(T(std::forward<ArgTypes>(Args)...));
  return this->back();
}

545public:
void push_back(ValueParamT Elt) {
  const T *EltPtr = reserveForParamAndGetAddress(Elt);
  memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T));
  this->set_size(this->size() + 1);
}

void pop_back() { this->set_size(this->size() - 1); }
553};

555/// This class consists of common code factored out of the SmallVector class to
556/// reduce code duplication based on the SmallVector 'N' template parameter.
557template <typename T>
558class SmallVectorImpl : public SmallVectorTemplateBase<T> {
using SuperClass = SmallVectorTemplateBase<T>;

561public:
using iterator = typename SuperClass::iterator;
using const_iterator = typename SuperClass::const_iterator;
using reference = typename SuperClass::reference;
using size_type = typename SuperClass::size_type;

567protected:
using SmallVectorTemplateBase<T>::TakesParamByValue;
using ValueParamT = typename SuperClass::ValueParamT;

// Default ctor - Initialize to empty.
explicit SmallVectorImpl(unsigned N)
    : SmallVectorTemplateBase<T>(N) {}

575public:
SmallVectorImpl(const SmallVectorImpl &) = delete;

~SmallVectorImpl() {
  // Subclass has already destructed this vector's elements.
  // If this wasn't grown from the inline copy, deallocate the old space.
  if (!this->isSmall())
    free(this->begin());
}

void clear() {
  this->destroy_range(this->begin(), this->end());
  this->Size = 0;
}

590private:
template <bool ForOverwrite> void resizeImpl(size_type N) {
  if (N < this->size()) {
    this->pop_back_n(this->size() - N);
  } else if (N > this->size()) {
    this->reserve(N);
    for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
      if (ForOverwrite)
        new (&*I) T;
      else
        new (&*I) T();
    this->set_size(N);
  }
}

605public:
void resize(size_type N) { resizeImpl<false>(N); }

/// Like resize, but \ref T is POD, the new values won't be initialized.
void resize_for_overwrite(size_type N) { resizeImpl<true>(N); }

void resize(size_type N, ValueParamT NV) {
  if (N == this->size())
    return;

  if (N < this->size()) {
    this->pop_back_n(this->size() - N);
    return;
  }

  // N > this->size(). Defer to append.
  this->append(N - this->size(), NV);
}

void reserve(size_type N) {
  if (this->capacity() < N)
    this->grow(N);
}

void pop_back_n(size_type NumItems) {
  assert(this->size() >= NumItems)((void)0);
  this->destroy_range(this->end() - NumItems, this->end());
  this->set_size(this->size() - NumItems);
}

LLVM_NODISCARD[[clang::warn_unused_result]] T pop_back_val() {
  T Result = ::std::move(this->back());
  this->pop_back();
  return Result;
}

void swap(SmallVectorImpl &RHS);

/// Add the specified range to the end of the SmallVector.
template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void append(in_iter in_start, in_iter in_end) {
  this->assertSafeToAddRange(in_start, in_end);
  size_type NumInputs = std::distance(in_start, in_end);
  this->reserve(this->size() + NumInputs);
  this->uninitialized_copy(in_start, in_end, this->end());
  this->set_size(this->size() + NumInputs);
}

/// Append \p NumInputs copies of \p Elt to the end.
void append(size_type NumInputs, ValueParamT Elt) {
  const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs);
  std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr);
  this->set_size(this->size() + NumInputs);
}

void append(std::initializer_list<T> IL) {
  append(IL.begin(), IL.end());
}

void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); }

void assign(size_type NumElts, ValueParamT Elt) {
  // Note that Elt could be an internal reference.
  if (NumElts > this->capacity()) {
    this->growAndAssign(NumElts, Elt);
    return;
  }

  // Assign over existing elements.
  std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt);
  if (NumElts > this->size())
    std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt);
  else if (NumElts < this->size())
    this->destroy_range(this->begin() + NumElts, this->end());
  this->set_size(NumElts);
}

// FIXME: Consider assigning over existing elements, rather than clearing &
// re-initializing them - for all assign(...) variants.

template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void assign(in_iter in_start, in_iter in_end) {
  this->assertSafeToReferenceAfterClear(in_start, in_end);
  clear();
  append(in_start, in_end);
}

void assign(std::initializer_list<T> IL) {
  clear();
  append(IL);
}

void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); }

iterator erase(const_iterator CI) {
  // Just cast away constness because this is a non-const member function.
  iterator I = const_cast<iterator>(CI);

  assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds.")((void)0);

  iterator N = I;
  // Shift all elts down one.
  std::move(I+1, this->end(), I);
  // Drop the last elt.
  this->pop_back();
  return(N);
}

iterator erase(const_iterator CS, const_iterator CE) {
  // Just cast away constness because this is a non-const member function.
  iterator S = const_cast<iterator>(CS);
  iterator E = const_cast<iterator>(CE);

  assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds.")((void)0);

  iterator N = S;
  // Shift all elts down.
  iterator I = std::move(E, this->end(), S);
  // Drop the last elts.
  this->destroy_range(I, this->end());
  this->set_size(I - this->begin());
  return(N);
}

735private:
template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) {
  // Callers ensure that ArgType is derived from T.
  static_assert(
      std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>,
                   T>::value,
      "ArgType must be derived from T!");

  if (I == this->end()) {  // Important special case for empty vector.
    this->push_back(::std::forward<ArgType>(Elt));
    return this->end()-1;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Grow if necessary.
  size_t Index = I - this->begin();
  std::remove_reference_t<ArgType> *EltPtr =
      this->reserveForParamAndGetAddress(Elt);
  I = this->begin() + Index;

  ::new ((void*) this->end()) T(::std::move(this->back()));
  // Push everything else over.
  std::move_backward(I, this->end()-1, this->end());
  this->set_size(this->size() + 1);

  // If we just moved the element we're inserting, be sure to update
  // the reference (never happens if TakesParamByValue).
  static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value,
                "ArgType must be 'T' when taking by value!");
  if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end()))
    ++EltPtr;

  *I = ::std::forward<ArgType>(*EltPtr);
  return I;
}

772public:
iterator insert(iterator I, T &&Elt) {
  return insert_one_impl(I, this->forward_value_param(std::move(Elt)));
}

iterator insert(iterator I, const T &Elt) {
  return insert_one_impl(I, this->forward_value_param(Elt));
}

iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(NumToInsert, Elt);
    return this->begin()+InsertElt;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Ensure there is enough space, and get the (maybe updated) address of
  // Elt.
  const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    // If we just moved the element we're inserting, be sure to update
    // the reference (never happens if TakesParamByValue).
    if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
      EltPtr += NumToInsert;

    std::fill_n(I, NumToInsert, *EltPtr);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // If we just moved the element we're inserting, be sure to update
  // the reference (never happens if TakesParamByValue).
  if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
    EltPtr += NumToInsert;

  // Replace the overwritten part.
  std::fill_n(I, NumOverwritten, *EltPtr);

  // Insert the non-overwritten middle part.
  std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr);
  return I;
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
iterator insert(iterator I, ItTy From, ItTy To) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(From, To);
    return this->begin()+InsertElt;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Check that the reserve that follows doesn't invalidate the iterators.
  this->assertSafeToAddRange(From, To);

  size_t NumToInsert = std::distance(From, To);

  // Ensure there is enough space.
  reserve(this->size() + NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    std::copy(From, To, I);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // Replace the overwritten part.
  for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
    *J = *From;
    ++J; ++From;
  }

  // Insert the non-overwritten middle part.
  this->uninitialized_copy(From, To, OldEnd);
  return I;
}

void insert(iterator I, std::initializer_list<T> IL) {
  insert(I, IL.begin(), IL.end());
}

template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...);

  ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
  this->set_size(this->size() + 1);
  return this->back();
}

SmallVectorImpl &operator=(const SmallVectorImpl &RHS);

SmallVectorImpl &operator=(SmallVectorImpl &&RHS);

bool operator==(const SmallVectorImpl &RHS) const {
  if (this->size() != RHS.size()) return false;
  return std::equal(this->begin(), this->end(), RHS.begin());
}
bool operator!=(const SmallVectorImpl &RHS) const {
  return !(*this == RHS);
}

bool operator<(const SmallVectorImpl &RHS) const {
  return std::lexicographical_compare(this->begin(), this->end(),
                                      RHS.begin(), RHS.end());
}
933};

935template <typename T>
936void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
if (this == &RHS) return;

// We can only avoid copying elements if neither vector is small.
if (!this->isSmall() && !RHS.isSmall()) {
  std::swap(this->BeginX, RHS.BeginX);
  std::swap(this->Size, RHS.Size);
  std::swap(this->Capacity, RHS.Capacity);
  return;
}
this->reserve(RHS.size());
RHS.reserve(this->size());

// Swap the shared elements.
size_t NumShared = this->size();
if (NumShared > RHS.size()) NumShared = RHS.size();
for (size_type i = 0; i != NumShared; ++i)
  std::swap((*this)[i], RHS[i]);

// Copy over the extra elts.
if (this->size() > RHS.size()) {
  size_t EltDiff = this->size() - RHS.size();
  this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
  RHS.set_size(RHS.size() + EltDiff);
  this->destroy_range(this->begin()+NumShared, this->end());
  this->set_size(NumShared);
} else if (RHS.size() > this->size()) {
  size_t EltDiff = RHS.size() - this->size();
  this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
  this->set_size(this->size() + EltDiff);
  this->destroy_range(RHS.begin()+NumShared, RHS.end());
  RHS.set_size(NumShared);
}
969}

971template <typename T>
972SmallVectorImpl<T> &SmallVectorImpl<T>::
operator=(const SmallVectorImpl<T> &RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd;
  if (RHSSize)
    NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
  else
    NewEnd = this->begin();

  // Destroy excess elements.
  this->destroy_range(NewEnd, this->end());

  // Trim.
  this->set_size(RHSSize);
  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: don't do this if they're efficiently moveable.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->clear();
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Copy construct the new elements in place.
this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);
return *this;
1017}

1019template <typename T>
1020SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If the RHS isn't small, clear this vector and then steal its buffer.
if (!RHS.isSmall()) {
  this->destroy_range(this->begin(), this->end());
  if (!this->isSmall()) free(this->begin());
  this->BeginX = RHS.BeginX;
  this->Size = RHS.Size;
  this->Capacity = RHS.Capacity;
  RHS.resetToSmall();
  return *this;
}

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd = this->begin();
  if (RHSSize)
    NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);

  // Destroy excess elements and trim the bounds.
  this->destroy_range(NewEnd, this->end());
  this->set_size(RHSSize);

  // Clear the RHS.
  RHS.clear();

  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: this may not actually make any sense if we can efficiently move
// elements.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->clear();
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Move-construct the new elements in place.
this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);

RHS.clear();
return *this;
1078}

1080/// Storage for the SmallVector elements.  This is specialized for the N=0 case
1081/// to avoid allocating unnecessary storage.
1082template <typename T, unsigned N>
1083struct SmallVectorStorage {
alignas(T) char InlineElts[N * sizeof(T)];
1085};

1087/// We need the storage to be properly aligned even for small-size of 0 so that
1088/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
1089/// well-defined.
1090template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {};

1092/// Forward declaration of SmallVector so that
1093/// calculateSmallVectorDefaultInlinedElements can reference
1094/// `sizeof(SmallVector<T, 0>)`.
1095template <typename T, unsigned N> class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector;

1097/// Helper class for calculating the default number of inline elements for
1098/// `SmallVector<T>`.
1099///
1100/// This should be migrated to a constexpr function when our minimum
1101/// compiler support is enough for multi-statement constexpr functions.
1102template <typename T> struct CalculateSmallVectorDefaultInlinedElements {
// Parameter controlling the default number of inlined elements
// for `SmallVector<T>`.
//
// The default number of inlined elements ensures that
// 1. There is at least one inlined element.
// 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless
// it contradicts 1.
static constexpr size_t kPreferredSmallVectorSizeof = 64;

// static_assert that sizeof(T) is not "too big".
//
// Because our policy guarantees at least one inlined element, it is possible
// for an arbitrarily large inlined element to allocate an arbitrarily large
// amount of inline storage. We generally consider it an antipattern for a
// SmallVector to allocate an excessive amount of inline storage, so we want
// to call attention to these cases and make sure that users are making an
// intentional decision if they request a lot of inline storage.
//
// We want this assertion to trigger in pathological cases, but otherwise
// not be too easy to hit. To accomplish that, the cutoff is actually somewhat
// larger than kPreferredSmallVectorSizeof (otherwise,
// `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that
// pattern seems useful in practice).
//
// One wrinkle is that this assertion is in theory non-portable, since
// sizeof(T) is in general platform-dependent. However, we don't expect this
// to be much of an issue, because most LLVM development happens on 64-bit
// hosts, and therefore sizeof(T) is expected to *decrease* when compiled for
// 32-bit hosts, dodging the issue. The reverse situation, where development
// happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a
// 64-bit host, is expected to be very rare.
static_assert(
    sizeof(T) <= 256,
    "You are trying to use a default number of inlined elements for "
    "`SmallVector<T>` but `sizeof(T)` is really big! Please use an "
    "explicit number of inlined elements with `SmallVector<T, N>` to make "
    "sure you really want that much inline storage.");

// Discount the size of the header itself when calculating the maximum inline
// bytes.
static constexpr size_t PreferredInlineBytes =
    kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>);
static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T);
static constexpr size_t value =
    NumElementsThatFit == 0 ? 1 : NumElementsThatFit;
1148};

1150/// This is a 'vector' (really, a variable-sized array), optimized
1151/// for the case when the array is small.  It contains some number of elements
1152/// in-place, which allows it to avoid heap allocation when the actual number of
1153/// elements is below that threshold.  This allows normal "small" cases to be
1154/// fast without losing generality for large inputs.
1155///
1156/// \note
1157/// In the absence of a well-motivated choice for the number of inlined
1158/// elements \p N, it is recommended to use \c SmallVector<T> (that is,
1159/// omitting the \p N). This will choose a default number of inlined elements
1160/// reasonable for allocation on the stack (for example, trying to keep \c
1161/// sizeof(SmallVector<T>) around 64 bytes).
1162///
1163/// \warning This does not attempt to be exception safe.
1164///
1165/// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h
1166template <typename T,
        unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value>
1168class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector : public SmallVectorImpl<T>,
                                 SmallVectorStorage<T, N> {
1170public:
SmallVector() : SmallVectorImpl<T>(N) {}

~SmallVector() {
  // Destroy the constructed elements in the vector.
  this->destroy_range(this->begin(), this->end());
}

explicit SmallVector(size_t Size, const T &Value = T())
  : SmallVectorImpl<T>(N) {
  this->assign(Size, Value);
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
  this->append(S, E);
}

template <typename RangeTy>
explicit SmallVector(const iterator_range<RangeTy> &R)
    : SmallVectorImpl<T>(N) {
  this->append(R.begin(), R.end());
}

SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
  this->assign(IL);
}

SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(RHS);
}

SmallVector &operator=(const SmallVector &RHS) {
  SmallVectorImpl<T>::operator=(RHS);
  return *this;
}

SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

SmallVector &operator=(SmallVector &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

SmallVector &operator=(std::initializer_list<T> IL) {
  this->assign(IL);
  return *this;
}
1235};

1237template <typename T, unsigned N>
1238inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
return X.capacity_in_bytes();
1240}

1242/// Given a range of type R, iterate the entire range and return a
1243/// SmallVector with elements of the vector.  This is useful, for example,
1244/// when you want to iterate a range and then sort the results.
1245template <unsigned Size, typename R>
1246SmallVector<typename std::remove_const<typename std::remove_reference<
              decltype(*std::begin(std::declval<R &>()))>::type>::type,
          Size>
1249to_vector(R &&Range) {
return {std::begin(Range), std::end(Range)};
1251}

1253} // end namespace llvm

1255namespace std {

/// Implement std::swap in terms of SmallVector swap.
template<typename T>
inline void
swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
  LHS.swap(RHS);
}

/// Implement std::swap in terms of SmallVector swap.
template<typename T, unsigned N>
inline void
swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
  LHS.swap(RHS);
}

1271} // end namespace std

1273#endif // LLVM_ADT_SMALLVECTOR_H

←

/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include/clang/Sema/Sema.h

1//===--- Sema.h - Semantic Analysis & AST Building --------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the Sema class, which performs semantic analysis and
10// builds ASTs.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_CLANG_SEMA_SEMA_H
15#define LLVM_CLANG_SEMA_SEMA_H

17#include "clang/AST/ASTConcept.h"
18#include "clang/AST/ASTFwd.h"
19#include "clang/AST/Attr.h"
20#include "clang/AST/Availability.h"
21#include "clang/AST/ComparisonCategories.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/ExprConcepts.h"
27#include "clang/AST/ExprObjC.h"
28#include "clang/AST/ExprOpenMP.h"
29#include "clang/AST/ExternalASTSource.h"
30#include "clang/AST/LocInfoType.h"
31#include "clang/AST/MangleNumberingContext.h"
32#include "clang/AST/NSAPI.h"
33#include "clang/AST/PrettyPrinter.h"
34#include "clang/AST/StmtCXX.h"
35#include "clang/AST/StmtOpenMP.h"
36#include "clang/AST/TypeLoc.h"
37#include "clang/AST/TypeOrdering.h"
38#include "clang/Basic/BitmaskEnum.h"
39#include "clang/Basic/Builtins.h"
40#include "clang/Basic/DarwinSDKInfo.h"
41#include "clang/Basic/ExpressionTraits.h"
42#include "clang/Basic/Module.h"
43#include "clang/Basic/OpenCLOptions.h"
44#include "clang/Basic/OpenMPKinds.h"
45#include "clang/Basic/PragmaKinds.h"
46#include "clang/Basic/Specifiers.h"
47#include "clang/Basic/TemplateKinds.h"
48#include "clang/Basic/TypeTraits.h"
49#include "clang/Sema/AnalysisBasedWarnings.h"
50#include "clang/Sema/CleanupInfo.h"
51#include "clang/Sema/DeclSpec.h"
52#include "clang/Sema/ExternalSemaSource.h"
53#include "clang/Sema/IdentifierResolver.h"
54#include "clang/Sema/ObjCMethodList.h"
55#include "clang/Sema/Ownership.h"
56#include "clang/Sema/Scope.h"
57#include "clang/Sema/SemaConcept.h"
58#include "clang/Sema/TypoCorrection.h"
59#include "clang/Sema/Weak.h"
60#include "llvm/ADT/ArrayRef.h"
61#include "llvm/ADT/Optional.h"
62#include "llvm/ADT/SetVector.h"
63#include "llvm/ADT/SmallBitVector.h"
64#include "llvm/ADT/SmallPtrSet.h"
65#include "llvm/ADT/SmallSet.h"
66#include "llvm/ADT/SmallVector.h"
67#include "llvm/ADT/TinyPtrVector.h"
68#include "llvm/Frontend/OpenMP/OMPConstants.h"
69#include <deque>
70#include <memory>
71#include <string>
72#include <tuple>
73#include <vector>

75namespace llvm {
class APSInt;
template <typename ValueT> struct DenseMapInfo;
template <typename ValueT, typename ValueInfoT> class DenseSet;
class SmallBitVector;
struct InlineAsmIdentifierInfo;
81}

83namespace clang {
class ADLResult;
class ASTConsumer;
class ASTContext;
class ASTMutationListener;
class ASTReader;
class ASTWriter;
class ArrayType;
class ParsedAttr;
class BindingDecl;
class BlockDecl;
class CapturedDecl;
class CXXBasePath;
class CXXBasePaths;
class CXXBindTemporaryExpr;
typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
class CXXConstructorDecl;
class CXXConversionDecl;
class CXXDeleteExpr;
class CXXDestructorDecl;
class CXXFieldCollector;
class CXXMemberCallExpr;
class CXXMethodDecl;
class CXXScopeSpec;
class CXXTemporary;
class CXXTryStmt;
class CallExpr;
class ClassTemplateDecl;
class ClassTemplatePartialSpecializationDecl;
class ClassTemplateSpecializationDecl;
class VarTemplatePartialSpecializationDecl;
class CodeCompleteConsumer;
class CodeCompletionAllocator;
class CodeCompletionTUInfo;
class CodeCompletionResult;
class CoroutineBodyStmt;
class Decl;
class DeclAccessPair;
class DeclContext;
class DeclRefExpr;
class DeclaratorDecl;
class DeducedTemplateArgument;
class DependentDiagnostic;
class DesignatedInitExpr;
class Designation;
class EnableIfAttr;
class EnumConstantDecl;
class Expr;
class ExtVectorType;
class FormatAttr;
class FriendDecl;
class FunctionDecl;
class FunctionProtoType;
class FunctionTemplateDecl;
class ImplicitConversionSequence;
typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
class InitListExpr;
class InitializationKind;
class InitializationSequence;
class InitializedEntity;
class IntegerLiteral;
class LabelStmt;
class LambdaExpr;
class LangOptions;
class LocalInstantiationScope;
class LookupResult;
class MacroInfo;
typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation>> ModuleIdPath;
class ModuleLoader;
class MultiLevelTemplateArgumentList;
class NamedDecl;
class ObjCCategoryDecl;
class ObjCCategoryImplDecl;
class ObjCCompatibleAliasDecl;
class ObjCContainerDecl;
class ObjCImplDecl;
class ObjCImplementationDecl;
class ObjCInterfaceDecl;
class ObjCIvarDecl;
template <class T> class ObjCList;
class ObjCMessageExpr;
class ObjCMethodDecl;
class ObjCPropertyDecl;
class ObjCProtocolDecl;
class OMPThreadPrivateDecl;
class OMPRequiresDecl;
class OMPDeclareReductionDecl;
class OMPDeclareSimdDecl;
class OMPClause;
struct OMPVarListLocTy;
struct OverloadCandidate;
enum class OverloadCandidateParamOrder : char;
enum OverloadCandidateRewriteKind : unsigned;
class OverloadCandidateSet;
class OverloadExpr;
class ParenListExpr;
class ParmVarDecl;
class Preprocessor;
class PseudoDestructorTypeStorage;
class PseudoObjectExpr;
class QualType;
class StandardConversionSequence;
class Stmt;
class StringLiteral;
class SwitchStmt;
class TemplateArgument;
class TemplateArgumentList;
class TemplateArgumentLoc;
class TemplateDecl;
class TemplateInstantiationCallback;
class TemplateParameterList;
class TemplatePartialOrderingContext;
class TemplateTemplateParmDecl;
class Token;
class TypeAliasDecl;
class TypedefDecl;
class TypedefNameDecl;
class TypeLoc;
class TypoCorrectionConsumer;
class UnqualifiedId;
class UnresolvedLookupExpr;
class UnresolvedMemberExpr;
class UnresolvedSetImpl;
class UnresolvedSetIterator;
class UsingDecl;
class UsingShadowDecl;
class ValueDecl;
class VarDecl;
class VarTemplateSpecializationDecl;
class VisibilityAttr;
class VisibleDeclConsumer;
class IndirectFieldDecl;
struct DeductionFailureInfo;
class TemplateSpecCandidateSet;

218namespace sema {
class AccessedEntity;
class BlockScopeInfo;
class Capture;
class CapturedRegionScopeInfo;
class CapturingScopeInfo;
class CompoundScopeInfo;
class DelayedDiagnostic;
class DelayedDiagnosticPool;
class FunctionScopeInfo;
class LambdaScopeInfo;
class PossiblyUnreachableDiag;
class SemaPPCallbacks;
class TemplateDeductionInfo;
232}

234namespace threadSafety {
class BeforeSet;
void threadSafetyCleanup(BeforeSet* Cache);
237}

239// FIXME: No way to easily map from TemplateTypeParmTypes to
240// TemplateTypeParmDecls, so we have this horrible PointerUnion.
241typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType*, NamedDecl*>,
                SourceLocation> UnexpandedParameterPack;

244/// Describes whether we've seen any nullability information for the given
245/// file.
246struct FileNullability {
/// The first pointer declarator (of any pointer kind) in the file that does
/// not have a corresponding nullability annotation.
SourceLocation PointerLoc;

/// The end location for the first pointer declarator in the file. Used for
/// placing fix-its.
SourceLocation PointerEndLoc;

/// Which kind of pointer declarator we saw.
uint8_t PointerKind;

/// Whether we saw any type nullability annotations in the given file.
bool SawTypeNullability = false;
260};

262/// A mapping from file IDs to a record of whether we've seen nullability
263/// information in that file.
264class FileNullabilityMap {
/// A mapping from file IDs to the nullability information for each file ID.
llvm::DenseMap<FileID, FileNullability> Map;

/// A single-element cache based on the file ID.
struct {
  FileID File;
  FileNullability Nullability;
} Cache;

274public:
FileNullability &operator[](FileID file) {
  // Check the single-element cache.
  if (file == Cache.File)
    return Cache.Nullability;

  // It's not in the single-element cache; flush the cache if we have one.
  if (!Cache.File.isInvalid()) {
    Map[Cache.File] = Cache.Nullability;
  }

  // Pull this entry into the cache.
  Cache.File = file;
  Cache.Nullability = Map[file];
  return Cache.Nullability;
}
290};

292/// Tracks expected type during expression parsing, for use in code completion.
293/// The type is tied to a particular token, all functions that update or consume
294/// the type take a start location of the token they are looking at as a
295/// parameter. This avoids updating the type on hot paths in the parser.
296class PreferredTypeBuilder {
297public:
PreferredTypeBuilder(bool Enabled) : Enabled(Enabled) {}

void enterCondition(Sema &S, SourceLocation Tok);
void enterReturn(Sema &S, SourceLocation Tok);
void enterVariableInit(SourceLocation Tok, Decl *D);
/// Handles e.g. BaseType{ .D = Tok...
void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
                                const Designation &D);
/// Computing a type for the function argument may require running
/// overloading, so we postpone its computation until it is actually needed.
///
/// Clients should be very careful when using this funciton, as it stores a
/// function_ref, clients should make sure all calls to get() with the same
/// location happen while function_ref is alive.
///
/// The callback should also emit signature help as a side-effect, but only
/// if the completion point has been reached.
void enterFunctionArgument(SourceLocation Tok,
                           llvm::function_ref<QualType()> ComputeType);

void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
                SourceLocation OpLoc);
void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
/// Handles all type casts, including C-style cast, C++ casts, etc.
void enterTypeCast(SourceLocation Tok, QualType CastType);

/// Get the expected type associated with this location, if any.
///
/// If the location is a function argument, determining the expected type
/// involves considering all function overloads and the arguments so far.
/// In this case, signature help for these function overloads will be reported
/// as a side-effect (only if the completion point has been reached).
QualType get(SourceLocation Tok) const {
  if (!Enabled || Tok != ExpectedLoc)
    return QualType();
  if (!Type.isNull())
    return Type;
  if (ComputeType)
    return ComputeType();
  return QualType();
}

343private:
bool Enabled;
/// Start position of a token for which we store expected type.
SourceLocation ExpectedLoc;
/// Expected type for a token starting at ExpectedLoc.
QualType Type;
/// A function to compute expected type at ExpectedLoc. It is only considered
/// if Type is null.
llvm::function_ref<QualType()> ComputeType;
352};

354/// Sema - This implements semantic analysis and AST building for C.
355class Sema final {
Sema(const Sema &) = delete;
void operator=(const Sema &) = delete;

///Source of additional semantic information.
ExternalSemaSource *ExternalSource;

///Whether Sema has generated a multiplexer and has to delete it.
bool isMultiplexExternalSource;

static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);

bool isVisibleSlow(const NamedDecl *D);

/// Determine whether two declarations should be linked together, given that
/// the old declaration might not be visible and the new declaration might
/// not have external linkage.
bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
                                  const NamedDecl *New) {
  if (isVisible(Old))
   return true;
  // See comment in below overload for why it's safe to compute the linkage
  // of the new declaration here.
  if (New->isExternallyDeclarable()) {
    assert(Old->isExternallyDeclarable() &&((void)0)
           "should not have found a non-externally-declarable previous decl")((void)0);
    return true;
  }
  return false;
}
bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);

void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
                                    QualType ResultTy,
                                    ArrayRef<QualType> Args);

391public:
/// The maximum alignment, same as in llvm::Value. We duplicate them here
/// because that allows us not to duplicate the constants in clang code,
/// which we must to since we can't directly use the llvm constants.
/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
///
/// This is the greatest alignment value supported by load, store, and alloca
/// instructions, and global values.
static const unsigned MaxAlignmentExponent = 29;
static const unsigned MaximumAlignment = 1u << MaxAlignmentExponent;

typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
typedef OpaquePtr<TemplateName> TemplateTy;
typedef OpaquePtr<QualType> TypeTy;

OpenCLOptions OpenCLFeatures;
FPOptions CurFPFeatures;

const LangOptions &LangOpts;
Preprocessor &PP;
ASTContext &Context;
ASTConsumer &Consumer;
DiagnosticsEngine &Diags;
SourceManager &SourceMgr;

/// Flag indicating whether or not to collect detailed statistics.
bool CollectStats;

/// Code-completion consumer.
CodeCompleteConsumer *CodeCompleter;

/// CurContext - This is the current declaration context of parsing.
DeclContext *CurContext;

/// Generally null except when we temporarily switch decl contexts,
/// like in \see ActOnObjCTemporaryExitContainerContext.
DeclContext *OriginalLexicalContext;

/// VAListTagName - The declaration name corresponding to __va_list_tag.
/// This is used as part of a hack to omit that class from ADL results.
DeclarationName VAListTagName;

bool MSStructPragmaOn; // True when \#pragma ms_struct on

/// Controls member pointer representation format under the MS ABI.
LangOptions::PragmaMSPointersToMembersKind
    MSPointerToMemberRepresentationMethod;

/// Stack of active SEH __finally scopes.  Can be empty.
SmallVector<Scope*, 2> CurrentSEHFinally;

/// Source location for newly created implicit MSInheritanceAttrs
SourceLocation ImplicitMSInheritanceAttrLoc;

/// Holds TypoExprs that are created from `createDelayedTypo`. This is used by
/// `TransformTypos` in order to keep track of any TypoExprs that are created
/// recursively during typo correction and wipe them away if the correction
/// fails.
llvm::SmallVector<TypoExpr *, 2> TypoExprs;

/// pragma clang section kind
enum PragmaClangSectionKind {
  PCSK_Invalid      = 0,
  PCSK_BSS          = 1,
  PCSK_Data         = 2,
  PCSK_Rodata       = 3,
  PCSK_Text         = 4,
  PCSK_Relro        = 5
 };

enum PragmaClangSectionAction {
  PCSA_Set     = 0,
  PCSA_Clear   = 1
};

struct PragmaClangSection {
  std::string SectionName;
  bool Valid = false;
  SourceLocation PragmaLocation;
};

 PragmaClangSection PragmaClangBSSSection;
 PragmaClangSection PragmaClangDataSection;
 PragmaClangSection PragmaClangRodataSection;
 PragmaClangSection PragmaClangRelroSection;
 PragmaClangSection PragmaClangTextSection;

enum PragmaMsStackAction {
  PSK_Reset     = 0x0,                // #pragma ()
  PSK_Set       = 0x1,                // #pragma (value)
  PSK_Push      = 0x2,                // #pragma (push[, id])
  PSK_Pop       = 0x4,                // #pragma (pop[, id])
  PSK_Show      = 0x8,                // #pragma (show) -- only for "pack"!
  PSK_Push_Set  = PSK_Push | PSK_Set, // #pragma (push[, id], value)
  PSK_Pop_Set   = PSK_Pop | PSK_Set,  // #pragma (pop[, id], value)
};

// #pragma pack and align.
class AlignPackInfo {
public:
  // `Native` represents default align mode, which may vary based on the
  // platform.
  enum Mode : unsigned char { Native, Natural, Packed, Mac68k };

  // #pragma pack info constructor
  AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
      : PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
    assert(Num == PackNumber && "The pack number has been truncated.")((void)0);
  }

  // #pragma align info constructor
  AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
      : PackAttr(false), AlignMode(M),
        PackNumber(M == Packed ? 1 : UninitPackVal), XLStack(IsXL) {}

  explicit AlignPackInfo(bool IsXL) : AlignPackInfo(Native, IsXL) {}

  AlignPackInfo() : AlignPackInfo(Native, false) {}

  // When a AlignPackInfo itself cannot be used, this returns an 32-bit
  // integer encoding for it. This should only be passed to
  // AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
  static uint32_t getRawEncoding(const AlignPackInfo &Info) {
    std::uint32_t Encoding{};
    if (Info.IsXLStack())
      Encoding |= IsXLMask;

    Encoding |= static_cast<uint32_t>(Info.getAlignMode()) << 1;

    if (Info.IsPackAttr())
      Encoding |= PackAttrMask;

    Encoding |= static_cast<uint32_t>(Info.getPackNumber()) << 4;

    return Encoding;
  }

  static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
    bool IsXL = static_cast<bool>(Encoding & IsXLMask);
    AlignPackInfo::Mode M =
        static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> 1);
    int PackNumber = (Encoding & PackNumMask) >> 4;

    if (Encoding & PackAttrMask)
      return AlignPackInfo(M, PackNumber, IsXL);

    return AlignPackInfo(M, IsXL);
  }

  bool IsPackAttr() const { return PackAttr; }

  bool IsAlignAttr() const { return !PackAttr; }

  Mode getAlignMode() const { return AlignMode; }

  unsigned getPackNumber() const { return PackNumber; }

  bool IsPackSet() const {
    // #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
    // attriute on a decl.
    return PackNumber != UninitPackVal && PackNumber != 0;
  }

  bool IsXLStack() const { return XLStack; }

  bool operator==(const AlignPackInfo &Info) const {
    return std::tie(AlignMode, PackNumber, PackAttr, XLStack) ==
           std::tie(Info.AlignMode, Info.PackNumber, Info.PackAttr,
                    Info.XLStack);
  }

  bool operator!=(const AlignPackInfo &Info) const {
    return !(*this == Info);
  }

private:
  /// \brief True if this is a pragma pack attribute,
  ///         not a pragma align attribute.
  bool PackAttr;

  /// \brief The alignment mode that is in effect.
  Mode AlignMode;

  /// \brief The pack number of the stack.
  unsigned char PackNumber;

  /// \brief True if it is a XL #pragma align/pack stack.
  bool XLStack;

  /// \brief Uninitialized pack value.
  static constexpr unsigned char UninitPackVal = -1;

  // Masks to encode and decode an AlignPackInfo.
  static constexpr uint32_t IsXLMask{0x0000'0001};
  static constexpr uint32_t AlignModeMask{0x0000'0006};
  static constexpr uint32_t PackAttrMask{0x00000'0008};
  static constexpr uint32_t PackNumMask{0x0000'01F0};
};

template<typename ValueType>
struct PragmaStack {
  struct Slot {
    llvm::StringRef StackSlotLabel;
    ValueType Value;
    SourceLocation PragmaLocation;
    SourceLocation PragmaPushLocation;
    Slot(llvm::StringRef StackSlotLabel, ValueType Value,
         SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
        : StackSlotLabel(StackSlotLabel), Value(Value),
          PragmaLocation(PragmaLocation),
          PragmaPushLocation(PragmaPushLocation) {}
  };

  void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
           llvm::StringRef StackSlotLabel, ValueType Value) {
    if (Action == PSK_Reset) {
      CurrentValue = DefaultValue;
      CurrentPragmaLocation = PragmaLocation;
      return;
    }
    if (Action & PSK_Push)
      Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
                         PragmaLocation);
    else if (Action & PSK_Pop) {
      if (!StackSlotLabel.empty()) {
        // If we've got a label, try to find it and jump there.
        auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
          return x.StackSlotLabel == StackSlotLabel;
        });
        // If we found the label so pop from there.
        if (I != Stack.rend()) {
          CurrentValue = I->Value;
          CurrentPragmaLocation = I->PragmaLocation;
          Stack.erase(std::prev(I.base()), Stack.end());
        }
      } else if (!Stack.empty()) {
        // We do not have a label, just pop the last entry.
        CurrentValue = Stack.back().Value;
        CurrentPragmaLocation = Stack.back().PragmaLocation;
        Stack.pop_back();
      }
    }
    if (Action & PSK_Set) {
      CurrentValue = Value;
      CurrentPragmaLocation = PragmaLocation;
    }
  }

  // MSVC seems to add artificial slots to #pragma stacks on entering a C++
  // method body to restore the stacks on exit, so it works like this:
  //
  //   struct S {
  //     #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
  //     void Method {}
  //     #pragma <name>(pop, InternalPragmaSlot)
  //   };
  //
  // It works even with #pragma vtordisp, although MSVC doesn't support
  //   #pragma vtordisp(push [, id], n)
  // syntax.
  //
  // Push / pop a named sentinel slot.
  void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
    assert((Action == PSK_Push || Action == PSK_Pop) &&((void)0)
           "Can only push / pop #pragma stack sentinels!")((void)0);
    Act(CurrentPragmaLocation, Action, Label, CurrentValue);
  }

  // Constructors.
  explicit PragmaStack(const ValueType &Default)
      : DefaultValue(Default), CurrentValue(Default) {}

  bool hasValue() const { return CurrentValue != DefaultValue; }

  SmallVector<Slot, 2> Stack;
  ValueType DefaultValue; // Value used for PSK_Reset action.
  ValueType CurrentValue;
  SourceLocation CurrentPragmaLocation;
};
// FIXME: We should serialize / deserialize these if they occur in a PCH (but
// we shouldn't do so if they're in a module).

/// Whether to insert vtordisps prior to virtual bases in the Microsoft
/// C++ ABI.  Possible values are 0, 1, and 2, which mean:
///
/// 0: Suppress all vtordisps
/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
///    structors
/// 2: Always insert vtordisps to support RTTI on partially constructed
///    objects
PragmaStack<MSVtorDispMode> VtorDispStack;
PragmaStack<AlignPackInfo> AlignPackStack;
// The current #pragma align/pack values and locations at each #include.
struct AlignPackIncludeState {
  AlignPackInfo CurrentValue;
  SourceLocation CurrentPragmaLocation;
  bool HasNonDefaultValue, ShouldWarnOnInclude;
};
SmallVector<AlignPackIncludeState, 8> AlignPackIncludeStack;
// Segment #pragmas.
PragmaStack<StringLiteral *> DataSegStack;
PragmaStack<StringLiteral *> BSSSegStack;
PragmaStack<StringLiteral *> ConstSegStack;
PragmaStack<StringLiteral *> CodeSegStack;

// This stack tracks the current state of Sema.CurFPFeatures.
PragmaStack<FPOptionsOverride> FpPragmaStack;
FPOptionsOverride CurFPFeatureOverrides() {
  FPOptionsOverride result;
  if (!FpPragmaStack.hasValue()) {
    result = FPOptionsOverride();
  } else {
    result = FpPragmaStack.CurrentValue;
  }
  return result;
}

// RAII object to push / pop sentinel slots for all MS #pragma stacks.
// Actions should be performed only if we enter / exit a C++ method body.
class PragmaStackSentinelRAII {
public:
  PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
  ~PragmaStackSentinelRAII();

private:
  Sema &S;
  StringRef SlotLabel;
  bool ShouldAct;
};

/// A mapping that describes the nullability we've seen in each header file.
FileNullabilityMap NullabilityMap;

/// Last section used with #pragma init_seg.
StringLiteral *CurInitSeg;
SourceLocation CurInitSegLoc;

/// VisContext - Manages the stack for \#pragma GCC visibility.
void *VisContext; // Really a "PragmaVisStack*"

/// This an attribute introduced by \#pragma clang attribute.
struct PragmaAttributeEntry {
  SourceLocation Loc;
  ParsedAttr *Attribute;
  SmallVector<attr::SubjectMatchRule, 4> MatchRules;
  bool IsUsed;
};

/// A push'd group of PragmaAttributeEntries.
struct PragmaAttributeGroup {
  /// The location of the push attribute.
  SourceLocation Loc;
  /// The namespace of this push group.
  const IdentifierInfo *Namespace;
  SmallVector<PragmaAttributeEntry, 2> Entries;
};

SmallVector<PragmaAttributeGroup, 2> PragmaAttributeStack;

/// The declaration that is currently receiving an attribute from the
/// #pragma attribute stack.
const Decl *PragmaAttributeCurrentTargetDecl;

/// This represents the last location of a "#pragma clang optimize off"
/// directive if such a directive has not been closed by an "on" yet. If
/// optimizations are currently "on", this is set to an invalid location.
SourceLocation OptimizeOffPragmaLocation;

/// Flag indicating if Sema is building a recovery call expression.
///
/// This flag is used to avoid building recovery call expressions
/// if Sema is already doing so, which would cause infinite recursions.
bool IsBuildingRecoveryCallExpr;

/// Used to control the generation of ExprWithCleanups.
CleanupInfo Cleanup;

/// ExprCleanupObjects - This is the stack of objects requiring
/// cleanup that are created by the current full expression.
SmallVector<ExprWithCleanups::CleanupObject, 8> ExprCleanupObjects;

/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
/// to a variable (constant) that may or may not be odr-used in this Expr, and
/// we won't know until all lvalue-to-rvalue and discarded value conversions
/// have been applied to all subexpressions of the enclosing full expression.
/// This is cleared at the end of each full expression.
using MaybeODRUseExprSet = llvm::SetVector<Expr *, SmallVector<Expr *, 4>,
                                           llvm::SmallPtrSet<Expr *, 4>>;
MaybeODRUseExprSet MaybeODRUseExprs;

std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;

/// Stack containing information about each of the nested
/// function, block, and method scopes that are currently active.
SmallVector<sema::FunctionScopeInfo *, 4> FunctionScopes;

/// The index of the first FunctionScope that corresponds to the current
/// context.
unsigned FunctionScopesStart = 0;

ArrayRef<sema::FunctionScopeInfo*> getFunctionScopes() const {
  return llvm::makeArrayRef(FunctionScopes.begin() + FunctionScopesStart,
                            FunctionScopes.end());
}

/// Stack containing information needed when in C++2a an 'auto' is encountered
/// in a function declaration parameter type specifier in order to invent a
/// corresponding template parameter in the enclosing abbreviated function
/// template. This information is also present in LambdaScopeInfo, stored in
/// the FunctionScopes stack.
SmallVector<InventedTemplateParameterInfo, 4> InventedParameterInfos;

/// The index of the first InventedParameterInfo that refers to the current
/// context.
unsigned InventedParameterInfosStart = 0;

ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
  return llvm::makeArrayRef(InventedParameterInfos.begin() +
                                InventedParameterInfosStart,
                            InventedParameterInfos.end());
}

typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadExtVectorDecls, 2, 2>
  ExtVectorDeclsType;

/// ExtVectorDecls - This is a list all the extended vector types. This allows
/// us to associate a raw vector type with one of the ext_vector type names.
/// This is only necessary for issuing pretty diagnostics.
ExtVectorDeclsType ExtVectorDecls;

/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
std::unique_ptr<CXXFieldCollector> FieldCollector;

typedef llvm::SmallSetVector<NamedDecl *, 16> NamedDeclSetType;

/// Set containing all declared private fields that are not used.
NamedDeclSetType UnusedPrivateFields;

/// Set containing all typedefs that are likely unused.
llvm::SmallSetVector<const TypedefNameDecl *, 4>
    UnusedLocalTypedefNameCandidates;

/// Delete-expressions to be analyzed at the end of translation unit
///
/// This list contains class members, and locations of delete-expressions
/// that could not be proven as to whether they mismatch with new-expression
/// used in initializer of the field.
typedef std::pair<SourceLocation, bool> DeleteExprLoc;
typedef llvm::SmallVector<DeleteExprLoc, 4> DeleteLocs;
llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;

typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;

/// PureVirtualClassDiagSet - a set of class declarations which we have
/// emitted a list of pure virtual functions. Used to prevent emitting the
/// same list more than once.
std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;

/// ParsingInitForAutoVars - a set of declarations with auto types for which
/// we are currently parsing the initializer.
llvm::SmallPtrSet<const Decl*, 4> ParsingInitForAutoVars;

/// Look for a locally scoped extern "C" declaration by the given name.
NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);

typedef LazyVector<VarDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadTentativeDefinitions, 2, 2>
  TentativeDefinitionsType;

/// All the tentative definitions encountered in the TU.
TentativeDefinitionsType TentativeDefinitions;

/// All the external declarations encoutered and used in the TU.
SmallVector<VarDecl *, 4> ExternalDeclarations;

typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadUnusedFileScopedDecls, 2, 2>
  UnusedFileScopedDeclsType;

/// The set of file scoped decls seen so far that have not been used
/// and must warn if not used. Only contains the first declaration.
UnusedFileScopedDeclsType UnusedFileScopedDecls;

typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadDelegatingConstructors, 2, 2>
  DelegatingCtorDeclsType;

/// All the delegating constructors seen so far in the file, used for
/// cycle detection at the end of the TU.
DelegatingCtorDeclsType DelegatingCtorDecls;

/// All the overriding functions seen during a class definition
/// that had their exception spec checks delayed, plus the overridden
/// function.
SmallVector<std::pair<const CXXMethodDecl*, const CXXMethodDecl*>, 2>
  DelayedOverridingExceptionSpecChecks;

/// All the function redeclarations seen during a class definition that had
/// their exception spec checks delayed, plus the prior declaration they
/// should be checked against. Except during error recovery, the new decl
/// should always be a friend declaration, as that's the only valid way to
/// redeclare a special member before its class is complete.
SmallVector<std::pair<FunctionDecl*, FunctionDecl*>, 2>
  DelayedEquivalentExceptionSpecChecks;

typedef llvm::MapVector<const FunctionDecl *,
                        std::unique_ptr<LateParsedTemplate>>
    LateParsedTemplateMapT;
LateParsedTemplateMapT LateParsedTemplateMap;

/// Callback to the parser to parse templated functions when needed.
typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
typedef void LateTemplateParserCleanupCB(void *P);
LateTemplateParserCB *LateTemplateParser;
LateTemplateParserCleanupCB *LateTemplateParserCleanup;
void *OpaqueParser;

void SetLateTemplateParser(LateTemplateParserCB *LTP,
                           LateTemplateParserCleanupCB *LTPCleanup,
                           void *P) {
  LateTemplateParser = LTP;
  LateTemplateParserCleanup = LTPCleanup;
  OpaqueParser = P;
}

// Does the work necessary to deal with a SYCL kernel lambda. At the moment,
// this just marks the list of lambdas required to name the kernel.
void AddSYCLKernelLambda(const FunctionDecl *FD);

class DelayedDiagnostics;

class DelayedDiagnosticsState {
  sema::DelayedDiagnosticPool *SavedPool;
  friend class Sema::DelayedDiagnostics;
};
typedef DelayedDiagnosticsState ParsingDeclState;
typedef DelayedDiagnosticsState ProcessingContextState;

/// A class which encapsulates the logic for delaying diagnostics
/// during parsing and other processing.
class DelayedDiagnostics {
  /// The current pool of diagnostics into which delayed
  /// diagnostics should go.
  sema::DelayedDiagnosticPool *CurPool;

public:
  DelayedDiagnostics() : CurPool(nullptr) {}

  /// Adds a delayed diagnostic.
  void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h

  /// Determines whether diagnostics should be delayed.
  bool shouldDelayDiagnostics() { return CurPool != nullptr; }

  /// Returns the current delayed-diagnostics pool.
  sema::DelayedDiagnosticPool *getCurrentPool() const {
    return CurPool;
  }

  /// Enter a new scope.  Access and deprecation diagnostics will be
  /// collected in this pool.
  DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = &pool;
    return state;
  }

  /// Leave a delayed-diagnostic state that was previously pushed.
  /// Do not emit any of the diagnostics.  This is performed as part
  /// of the bookkeeping of popping a pool "properly".
  void popWithoutEmitting(DelayedDiagnosticsState state) {
    CurPool = state.SavedPool;
  }

  /// Enter a new scope where access and deprecation diagnostics are
  /// not delayed.
  DelayedDiagnosticsState pushUndelayed() {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = nullptr;
    return state;
  }

  /// Undo a previous pushUndelayed().
  void popUndelayed(DelayedDiagnosticsState state) {
    assert(CurPool == nullptr)((void)0);
    CurPool = state.SavedPool;
  }
} DelayedDiagnostics;

/// A RAII object to temporarily push a declaration context.
class ContextRAII {
private:
  Sema &S;
  DeclContext *SavedContext;
  ProcessingContextState SavedContextState;
  QualType SavedCXXThisTypeOverride;
  unsigned SavedFunctionScopesStart;
  unsigned SavedInventedParameterInfosStart;

public:
  ContextRAII(Sema &S, DeclContext *ContextToPush, bool NewThisContext = true)
    : S(S), SavedContext(S.CurContext),
      SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
      SavedCXXThisTypeOverride(S.CXXThisTypeOverride),
      SavedFunctionScopesStart(S.FunctionScopesStart),
      SavedInventedParameterInfosStart(S.InventedParameterInfosStart)
  {
    assert(ContextToPush && "pushing null context")((void)0);
    S.CurContext = ContextToPush;
    if (NewThisContext)
      S.CXXThisTypeOverride = QualType();
    // Any saved FunctionScopes do not refer to this context.
    S.FunctionScopesStart = S.FunctionScopes.size();
    S.InventedParameterInfosStart = S.InventedParameterInfos.size();
  }

  void pop() {
    if (!SavedContext) return;
    S.CurContext = SavedContext;
    S.DelayedDiagnostics.popUndelayed(SavedContextState);
    S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
    S.FunctionScopesStart = SavedFunctionScopesStart;
    S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
    SavedContext = nullptr;
  }

  ~ContextRAII() {
    pop();
  }
};

/// Whether the AST is currently being rebuilt to correct immediate
/// invocations. Immediate invocation candidates and references to consteval
/// functions aren't tracked when this is set.
bool RebuildingImmediateInvocation = false;

/// Used to change context to isConstantEvaluated without pushing a heavy
/// ExpressionEvaluationContextRecord object.
bool isConstantEvaluatedOverride;

bool isConstantEvaluated() {
  return ExprEvalContexts.back().isConstantEvaluated() ||
         isConstantEvaluatedOverride;
}

/// RAII object to handle the state changes required to synthesize
/// a function body.
class SynthesizedFunctionScope {
  Sema &S;
  Sema::ContextRAII SavedContext;
  bool PushedCodeSynthesisContext = false;

public:
  SynthesizedFunctionScope(Sema &S, DeclContext *DC)
      : S(S), SavedContext(S, DC) {
    S.PushFunctionScope();
    S.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
    if (auto *FD = dyn_cast<FunctionDecl>(DC))
      FD->setWillHaveBody(true);
    else
      assert(isa<ObjCMethodDecl>(DC))((void)0);
  }

  void addContextNote(SourceLocation UseLoc) {
    assert(!PushedCodeSynthesisContext)((void)0);

    Sema::CodeSynthesisContext Ctx;
    Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
    Ctx.PointOfInstantiation = UseLoc;
    Ctx.Entity = cast<Decl>(S.CurContext);
    S.pushCodeSynthesisContext(Ctx);

    PushedCodeSynthesisContext = true;
  }

  ~SynthesizedFunctionScope() {
    if (PushedCodeSynthesisContext)
      S.popCodeSynthesisContext();
    if (auto *FD = dyn_cast<FunctionDecl>(S.CurContext))
      FD->setWillHaveBody(false);
    S.PopExpressionEvaluationContext();
    S.PopFunctionScopeInfo();
  }
};

/// WeakUndeclaredIdentifiers - Identifiers contained in
/// \#pragma weak before declared. rare. may alias another
/// identifier, declared or undeclared
llvm::MapVector<IdentifierInfo *, WeakInfo> WeakUndeclaredIdentifiers;

/// ExtnameUndeclaredIdentifiers - Identifiers contained in
/// \#pragma redefine_extname before declared.  Used in Solaris system headers
/// to define functions that occur in multiple standards to call the version
/// in the currently selected standard.
llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*> ExtnameUndeclaredIdentifiers;


/// Load weak undeclared identifiers from the external source.
void LoadExternalWeakUndeclaredIdentifiers();

/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
/// \#pragma weak during processing of other Decls.
/// I couldn't figure out a clean way to generate these in-line, so
/// we store them here and handle separately -- which is a hack.
/// It would be best to refactor this.
SmallVector<Decl*,2> WeakTopLevelDecl;

IdentifierResolver IdResolver;

/// Translation Unit Scope - useful to Objective-C actions that need
/// to lookup file scope declarations in the "ordinary" C decl namespace.
/// For example, user-defined classes, built-in "id" type, etc.
Scope *TUScope;

/// The C++ "std" namespace, where the standard library resides.
LazyDeclPtr StdNamespace;

/// The C++ "std::bad_alloc" class, which is defined by the C++
/// standard library.
LazyDeclPtr StdBadAlloc;

/// The C++ "std::align_val_t" enum class, which is defined by the C++
/// standard library.
LazyDeclPtr StdAlignValT;

/// The C++ "std::experimental" namespace, where the experimental parts
/// of the standard library resides.
NamespaceDecl *StdExperimentalNamespaceCache;

/// The C++ "std::initializer_list" template, which is defined in
/// \<initializer_list>.
ClassTemplateDecl *StdInitializerList;

/// The C++ "std::coroutine_traits" template, which is defined in
/// \<coroutine_traits>
ClassTemplateDecl *StdCoroutineTraitsCache;

/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
RecordDecl *CXXTypeInfoDecl;

/// The MSVC "_GUID" struct, which is defined in MSVC header files.
RecordDecl *MSVCGuidDecl;

/// Caches identifiers/selectors for NSFoundation APIs.
std::unique_ptr<NSAPI> NSAPIObj;

/// The declaration of the Objective-C NSNumber class.
ObjCInterfaceDecl *NSNumberDecl;

/// The declaration of the Objective-C NSValue class.
ObjCInterfaceDecl *NSValueDecl;

/// Pointer to NSNumber type (NSNumber *).
QualType NSNumberPointer;

/// Pointer to NSValue type (NSValue *).
QualType NSValuePointer;

/// The Objective-C NSNumber methods used to create NSNumber literals.
ObjCMethodDecl *NSNumberLiteralMethods[NSAPI::NumNSNumberLiteralMethods];

/// The declaration of the Objective-C NSString class.
ObjCInterfaceDecl *NSStringDecl;

/// Pointer to NSString type (NSString *).
QualType NSStringPointer;

/// The declaration of the stringWithUTF8String: method.
ObjCMethodDecl *StringWithUTF8StringMethod;

/// The declaration of the valueWithBytes:objCType: method.
ObjCMethodDecl *ValueWithBytesObjCTypeMethod;

/// The declaration of the Objective-C NSArray class.
ObjCInterfaceDecl *NSArrayDecl;

/// The declaration of the arrayWithObjects:count: method.
ObjCMethodDecl *ArrayWithObjectsMethod;

/// The declaration of the Objective-C NSDictionary class.
ObjCInterfaceDecl *NSDictionaryDecl;

/// The declaration of the dictionaryWithObjects:forKeys:count: method.
ObjCMethodDecl *DictionaryWithObjectsMethod;

/// id<NSCopying> type.
QualType QIDNSCopying;

/// will hold 'respondsToSelector:'
Selector RespondsToSelectorSel;

/// A flag to remember whether the implicit forms of operator new and delete
/// have been declared.
bool GlobalNewDeleteDeclared;

/// Describes how the expressions currently being parsed are
/// evaluated at run-time, if at all.
enum class ExpressionEvaluationContext {
  /// The current expression and its subexpressions occur within an
  /// unevaluated operand (C++11 [expr]p7), such as the subexpression of
  /// \c sizeof, where the type of the expression may be significant but
  /// no code will be generated to evaluate the value of the expression at
  /// run time.
  Unevaluated,

  /// The current expression occurs within a braced-init-list within
  /// an unevaluated operand. This is mostly like a regular unevaluated
  /// context, except that we still instantiate constexpr functions that are
  /// referenced here so that we can perform narrowing checks correctly.
  UnevaluatedList,

  /// The current expression occurs within a discarded statement.
  /// This behaves largely similarly to an unevaluated operand in preventing
  /// definitions from being required, but not in other ways.
  DiscardedStatement,

  /// The current expression occurs within an unevaluated
  /// operand that unconditionally permits abstract references to
  /// fields, such as a SIZE operator in MS-style inline assembly.
  UnevaluatedAbstract,

  /// The current context is "potentially evaluated" in C++11 terms,
  /// but the expression is evaluated at compile-time (like the values of
  /// cases in a switch statement).
  ConstantEvaluated,

  /// The current expression is potentially evaluated at run time,
  /// which means that code may be generated to evaluate the value of the
  /// expression at run time.
  PotentiallyEvaluated,

  /// The current expression is potentially evaluated, but any
  /// declarations referenced inside that expression are only used if
  /// in fact the current expression is used.
  ///
  /// This value is used when parsing default function arguments, for which
  /// we would like to provide diagnostics (e.g., passing non-POD arguments
  /// through varargs) but do not want to mark declarations as "referenced"
  /// until the default argument is used.
  PotentiallyEvaluatedIfUsed
};

using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, 1>;

/// Data structure used to record current or nested
/// expression evaluation contexts.
struct ExpressionEvaluationContextRecord {
  /// The expression evaluation context.
  ExpressionEvaluationContext Context;

  /// Whether the enclosing context needed a cleanup.
  CleanupInfo ParentCleanup;

  /// The number of active cleanup objects when we entered
  /// this expression evaluation context.
  unsigned NumCleanupObjects;

  /// The number of typos encountered during this expression evaluation
  /// context (i.e. the number of TypoExprs created).
  unsigned NumTypos;

  MaybeODRUseExprSet SavedMaybeODRUseExprs;

  /// The lambdas that are present within this context, if it
  /// is indeed an unevaluated context.
  SmallVector<LambdaExpr *, 2> Lambdas;

  /// The declaration that provides context for lambda expressions
  /// and block literals if the normal declaration context does not
  /// suffice, e.g., in a default function argument.
  Decl *ManglingContextDecl;

  /// If we are processing a decltype type, a set of call expressions
  /// for which we have deferred checking the completeness of the return type.
  SmallVector<CallExpr *, 8> DelayedDecltypeCalls;

  /// If we are processing a decltype type, a set of temporary binding
  /// expressions for which we have deferred checking the destructor.
  SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;

  llvm::SmallPtrSet<const Expr *, 8> PossibleDerefs;

  /// Expressions appearing as the LHS of a volatile assignment in this
  /// context. We produce a warning for these when popping the context if
  /// they are not discarded-value expressions nor unevaluated operands.
  SmallVector<Expr*, 2> VolatileAssignmentLHSs;

  /// Set of candidates for starting an immediate invocation.
  llvm::SmallVector<ImmediateInvocationCandidate, 4> ImmediateInvocationCandidates;

  /// Set of DeclRefExprs referencing a consteval function when used in a
  /// context not already known to be immediately invoked.
  llvm::SmallPtrSet<DeclRefExpr *, 4> ReferenceToConsteval;

  /// \brief Describes whether we are in an expression constext which we have
  /// to handle differently.
  enum ExpressionKind {
    EK_Decltype, EK_TemplateArgument, EK_Other
  } ExprContext;

  ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                    unsigned NumCleanupObjects,
                                    CleanupInfo ParentCleanup,
                                    Decl *ManglingContextDecl,
                                    ExpressionKind ExprContext)
      : Context(Context), ParentCleanup(ParentCleanup),
        NumCleanupObjects(NumCleanupObjects), NumTypos(0),
        ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext) {}

  bool isUnevaluated() const {
    return Context == ExpressionEvaluationContext::Unevaluated ||
           Context == ExpressionEvaluationContext::UnevaluatedAbstract ||
           Context == ExpressionEvaluationContext::UnevaluatedList;
  }
  bool isConstantEvaluated() const {
    return Context == ExpressionEvaluationContext::ConstantEvaluated;
  }
};

/// A stack of expression evaluation contexts.
SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;

/// Emit a warning for all pending noderef expressions that we recorded.
void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);

/// Compute the mangling number context for a lambda expression or
/// block literal. Also return the extra mangling decl if any.
///
/// \param DC - The DeclContext containing the lambda expression or
/// block literal.
std::tuple<MangleNumberingContext *, Decl *>
getCurrentMangleNumberContext(const DeclContext *DC);


/// SpecialMemberOverloadResult - The overloading result for a special member
/// function.
///
/// This is basically a wrapper around PointerIntPair. The lowest bits of the
/// integer are used to determine whether overload resolution succeeded.
class SpecialMemberOverloadResult {
public:
  enum Kind {
    NoMemberOrDeleted,
    Ambiguous,
    Success
  };

private:
  llvm::PointerIntPair<CXXMethodDecl*, 2> Pair;

public:
  SpecialMemberOverloadResult() : Pair() {}
  SpecialMemberOverloadResult(CXXMethodDecl *MD)
      : Pair(MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}

  CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
  void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }

  Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
  void setKind(Kind K) { Pair.setInt(K); }
};

class SpecialMemberOverloadResultEntry
    : public llvm::FastFoldingSetNode,
      public SpecialMemberOverloadResult {
public:
  SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
    : FastFoldingSetNode(ID)
  {}
};

/// A cache of special member function overload resolution results
/// for C++ records.
llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;

/// A cache of the flags available in enumerations with the flag_bits
/// attribute.
mutable llvm::DenseMap<const EnumDecl*, llvm::APInt> FlagBitsCache;

/// The kind of translation unit we are processing.
///
/// When we're processing a complete translation unit, Sema will perform
/// end-of-translation-unit semantic tasks (such as creating
/// initializers for tentative definitions in C) once parsing has
/// completed. Modules and precompiled headers perform different kinds of
/// checks.
const TranslationUnitKind TUKind;

llvm::BumpPtrAllocator BumpAlloc;

/// The number of SFINAE diagnostics that have been trapped.
unsigned NumSFINAEErrors;

typedef llvm::DenseMap<ParmVarDecl *, llvm::TinyPtrVector<ParmVarDecl *>>
  UnparsedDefaultArgInstantiationsMap;

/// A mapping from parameters with unparsed default arguments to the
/// set of instantiations of each parameter.
///
/// This mapping is a temporary data structure used when parsing
/// nested class templates or nested classes of class templates,
/// where we might end up instantiating an inner class before the
/// default arguments of its methods have been parsed.
UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;

// Contains the locations of the beginning of unparsed default
// argument locations.
llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;

/// UndefinedInternals - all the used, undefined objects which require a
/// definition in this translation unit.
llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;

/// Determine if VD, which must be a variable or function, is an external
/// symbol that nonetheless can't be referenced from outside this translation
/// unit because its type has no linkage and it's not extern "C".
bool isExternalWithNoLinkageType(ValueDecl *VD);

/// Obtain a sorted list of functions that are undefined but ODR-used.
void getUndefinedButUsed(
    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);

/// Retrieves list of suspicious delete-expressions that will be checked at
/// the end of translation unit.
const llvm::MapVector<FieldDecl *, DeleteLocs> &
getMismatchingDeleteExpressions() const;

typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
typedef llvm::DenseMap<Selector, GlobalMethods> GlobalMethodPool;

/// Method Pool - allows efficient lookup when typechecking messages to "id".
/// We need to maintain a list, since selectors can have differing signatures
/// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
/// of selectors are "overloaded").
/// At the head of the list it is recorded whether there were 0, 1, or >= 2
/// methods inside categories with a particular selector.
GlobalMethodPool MethodPool;

/// Method selectors used in a \@selector expression. Used for implementation
/// of -Wselector.
llvm::MapVector<Selector, SourceLocation> ReferencedSelectors;

/// List of SourceLocations where 'self' is implicitly retained inside a
/// block.
llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, 1>
    ImplicitlyRetainedSelfLocs;

/// Kinds of C++ special members.
enum CXXSpecialMember {
  CXXDefaultConstructor,
  CXXCopyConstructor,
  CXXMoveConstructor,
  CXXCopyAssignment,
  CXXMoveAssignment,
  CXXDestructor,
  CXXInvalid
};

typedef llvm::PointerIntPair<CXXRecordDecl *, 3, CXXSpecialMember>
    SpecialMemberDecl;

/// The C++ special members which we are currently in the process of
/// declaring. If this process recursively triggers the declaration of the
/// same special member, we should act as if it is not yet declared.
llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;

/// Kinds of defaulted comparison operator functions.
enum class DefaultedComparisonKind : unsigned char {
  /// This is not a defaultable comparison operator.
  None,
  /// This is an operator== that should be implemented as a series of
  /// subobject comparisons.
  Equal,
  /// This is an operator<=> that should be implemented as a series of
  /// subobject comparisons.
  ThreeWay,
  /// This is an operator!= that should be implemented as a rewrite in terms
  /// of a == comparison.
  NotEqual,
  /// This is an <, <=, >, or >= that should be implemented as a rewrite in
  /// terms of a <=> comparison.
  Relational,
};

/// The function definitions which were renamed as part of typo-correction
/// to match their respective declarations. We want to keep track of them
/// to ensure that we don't emit a "redefinition" error if we encounter a
/// correctly named definition after the renamed definition.
llvm::SmallPtrSet<const NamedDecl *, 4> TypoCorrectedFunctionDefinitions;

/// Stack of types that correspond to the parameter entities that are
/// currently being copy-initialized. Can be empty.
llvm::SmallVector<QualType, 4> CurrentParameterCopyTypes;

void ReadMethodPool(Selector Sel);
void updateOutOfDateSelector(Selector Sel);

/// Private Helper predicate to check for 'self'.
bool isSelfExpr(Expr *RExpr);
bool isSelfExpr(Expr *RExpr, const ObjCMethodDecl *Method);

/// Cause the active diagnostic on the DiagosticsEngine to be
/// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
/// should not be used elsewhere.
void EmitCurrentDiagnostic(unsigned DiagID);

/// Records and restores the CurFPFeatures state on entry/exit of compound
/// statements.
class FPFeaturesStateRAII {
public:
  FPFeaturesStateRAII(Sema &S) : S(S), OldFPFeaturesState(S.CurFPFeatures) {
    OldOverrides = S.FpPragmaStack.CurrentValue;
  }
  ~FPFeaturesStateRAII() {
    S.CurFPFeatures = OldFPFeaturesState;
    S.FpPragmaStack.CurrentValue = OldOverrides;
  }
  FPOptionsOverride getOverrides() { return OldOverrides; }

private:
  Sema& S;
  FPOptions OldFPFeaturesState;
  FPOptionsOverride OldOverrides;
};

void addImplicitTypedef(StringRef Name, QualType T);

bool WarnedStackExhausted = false;

/// Increment when we find a reference; decrement when we find an ignored
/// assignment.  Ultimately the value is 0 if every reference is an ignored
/// assignment.
llvm::DenseMap<const VarDecl *, int> RefsMinusAssignments;

Optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;

1531public:
Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     TranslationUnitKind TUKind = TU_Complete,
     CodeCompleteConsumer *CompletionConsumer = nullptr);
~Sema();

/// Perform initialization that occurs after the parser has been
/// initialized but before it parses anything.
void Initialize();

/// This virtual key function only exists to limit the emission of debug info
/// describing the Sema class. GCC and Clang only emit debug info for a class
/// with a vtable when the vtable is emitted. Sema is final and not
/// polymorphic, but the debug info size savings are so significant that it is
/// worth adding a vtable just to take advantage of this optimization.
virtual void anchor();

const LangOptions &getLangOpts() const { return LangOpts; }
OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
FPOptions     &getCurFPFeatures() { return CurFPFeatures; }

DiagnosticsEngine &getDiagnostics() const { return Diags; }
SourceManager &getSourceManager() const { return SourceMgr; }
Preprocessor &getPreprocessor() const { return PP; }
ASTContext &getASTContext() const { return Context; }
ASTConsumer &getASTConsumer() const { return Consumer; }
ASTMutationListener *getASTMutationListener() const;
ExternalSemaSource* getExternalSource() const { return ExternalSource; }
DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
                                                       StringRef Platform);

///Registers an external source. If an external source already exists,
/// creates a multiplex external source and appends to it.
///
///\param[in] E - A non-null external sema source.
///
void addExternalSource(ExternalSemaSource *E);

void PrintStats() const;

/// Warn that the stack is nearly exhausted.
void warnStackExhausted(SourceLocation Loc);

/// Run some code with "sufficient" stack space. (Currently, at least 256K is
/// guaranteed). Produces a warning if we're low on stack space and allocates
/// more in that case. Use this in code that may recurse deeply (for example,
/// in template instantiation) to avoid stack overflow.
void runWithSufficientStackSpace(SourceLocation Loc,
                                 llvm::function_ref<void()> Fn);

/// Helper class that creates diagnostics with optional
/// template instantiation stacks.
///
/// This class provides a wrapper around the basic DiagnosticBuilder
/// class that emits diagnostics. ImmediateDiagBuilder is
/// responsible for emitting the diagnostic (as DiagnosticBuilder
/// does) and, if the diagnostic comes from inside a template
/// instantiation, printing the template instantiation stack as
/// well.
class ImmediateDiagBuilder : public DiagnosticBuilder {
  Sema &SemaRef;
  unsigned DiagID;

public:
  ImmediateDiagBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}
  ImmediateDiagBuilder(DiagnosticBuilder &&DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}

  // This is a cunning lie. DiagnosticBuilder actually performs move
  // construction in its copy constructor (but due to varied uses, it's not
  // possible to conveniently express this as actual move construction). So
  // the default copy ctor here is fine, because the base class disables the
  // source anyway, so the user-defined ~ImmediateDiagBuilder is a safe no-op
  // in that case anwyay.
  ImmediateDiagBuilder(const ImmediateDiagBuilder &) = default;

  ~ImmediateDiagBuilder() {
    // If we aren't active, there is nothing to do.
    if (!isActive()) return;

    // Otherwise, we need to emit the diagnostic. First clear the diagnostic
    // builder itself so it won't emit the diagnostic in its own destructor.
    //
    // This seems wasteful, in that as written the DiagnosticBuilder dtor will
    // do its own needless checks to see if the diagnostic needs to be
    // emitted. However, because we take care to ensure that the builder
    // objects never escape, a sufficiently smart compiler will be able to
    // eliminate that code.
    Clear();

    // Dispatch to Sema to emit the diagnostic.
    SemaRef.EmitCurrentDiagnostic(DiagID);
  }

  /// Teach operator<< to produce an object of the correct type.
  template <typename T>
  friend const ImmediateDiagBuilder &
  operator<<(const ImmediateDiagBuilder &Diag, const T &Value) {
    const DiagnosticBuilder &BaseDiag = Diag;
    BaseDiag << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T, typename = typename std::enable_if<
                            !std::is_lvalue_reference<T>::value>::type>
  const ImmediateDiagBuilder &operator<<(T &&V) const {
    const DiagnosticBuilder &BaseDiag = *this;
    BaseDiag << std::move(V);
    return *this;
  }
};

/// A generic diagnostic builder for errors which may or may not be deferred.
///
/// In CUDA, there exist constructs (e.g. variable-length arrays, try/catch)
/// which are not allowed to appear inside __device__ functions and are
/// allowed to appear in __host__ __device__ functions only if the host+device
/// function is never codegen'ed.
///
/// To handle this, we use the notion of "deferred diagnostics", where we
/// attach a diagnostic to a FunctionDecl that's emitted iff it's codegen'ed.
///
/// This class lets you emit either a regular diagnostic, a deferred
/// diagnostic, or no diagnostic at all, according to an argument you pass to
/// its constructor, thus simplifying the process of creating these "maybe
/// deferred" diagnostics.
class SemaDiagnosticBuilder {
public:
  enum Kind {
    /// Emit no diagnostics.
    K_Nop,
    /// Emit the diagnostic immediately (i.e., behave like Sema::Diag()).
    K_Immediate,
    /// Emit the diagnostic immediately, and, if it's a warning or error, also
    /// emit a call stack showing how this function can be reached by an a
    /// priori known-emitted function.
    K_ImmediateWithCallStack,
    /// Create a deferred diagnostic, which is emitted only if the function
    /// it's attached to is codegen'ed.  Also emit a call stack as with
    /// K_ImmediateWithCallStack.
    K_Deferred
  };

  SemaDiagnosticBuilder(Kind K, SourceLocation Loc, unsigned DiagID,
                        FunctionDecl *Fn, Sema &S);
  SemaDiagnosticBuilder(SemaDiagnosticBuilder &&D);
  SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
  ~SemaDiagnosticBuilder();

  bool isImmediate() const { return ImmediateDiag.hasValue(); }

  /// Convertible to bool: True if we immediately emitted an error, false if
  /// we didn't emit an error or we created a deferred error.
  ///
  /// Example usage:
  ///
  ///   if (SemaDiagnosticBuilder(...) << foo << bar)
  ///     return ExprError();
  ///
  /// But see CUDADiagIfDeviceCode() and CUDADiagIfHostCode() -- you probably
  /// want to use these instead of creating a SemaDiagnosticBuilder yourself.
  operator bool() const { return isImmediate(); }

  template <typename T>
  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const T &Value) {
    if (Diag.ImmediateDiag.hasValue())
      *Diag.ImmediateDiag << Value;
    else if (Diag.PartialDiagId.hasValue())
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second
          << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T, typename = typename std::enable_if<
                            !std::is_lvalue_reference<T>::value>::type>
  const SemaDiagnosticBuilder &operator<<(T &&V) const {
    if (ImmediateDiag.hasValue())
      *ImmediateDiag << std::move(V);
    else if (PartialDiagId.hasValue())
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second << std::move(V);
    return *this;
  }

  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const PartialDiagnostic &PD) {
    if (Diag.ImmediateDiag.hasValue())
      PD.Emit(*Diag.ImmediateDiag);
    else if (Diag.PartialDiagId.hasValue())
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second = PD;
    return Diag;
  }

  void AddFixItHint(const FixItHint &Hint) const {
    if (ImmediateDiag.hasValue())
      ImmediateDiag->AddFixItHint(Hint);
    else if (PartialDiagId.hasValue())
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second.AddFixItHint(Hint);
  }

  friend ExprResult ExprError(const SemaDiagnosticBuilder &) {
    return ExprError();
  }
  friend StmtResult StmtError(const SemaDiagnosticBuilder &) {
    return StmtError();
  }
  operator ExprResult() const { return ExprError(); }
  operator StmtResult() const { return StmtError(); }
  operator TypeResult() const { return TypeError(); }
  operator DeclResult() const { return DeclResult(true); }
  operator MemInitResult() const { return MemInitResult(true); }

private:
  Sema &S;
  SourceLocation Loc;
  unsigned DiagID;
  FunctionDecl *Fn;
  bool ShowCallStack;

  // Invariant: At most one of these Optionals has a value.
  // FIXME: Switch these to a Variant once that exists.
  llvm::Optional<ImmediateDiagBuilder> ImmediateDiag;
  llvm::Optional<unsigned> PartialDiagId;
};

/// Is the last error level diagnostic immediate. This is used to determined
/// whether the next info diagnostic should be immediate.
bool IsLastErrorImmediate = true;

/// Emit a diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID,
                           bool DeferHint = false);

/// Emit a partial diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic &PD,
                           bool DeferHint = false);

/// Build a partial diagnostic.
PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h

/// Whether deferrable diagnostics should be deferred.
bool DeferDiags = false;

/// RAII class to control scope of DeferDiags.
class DeferDiagsRAII {
  Sema &S;
  bool SavedDeferDiags = false;

public:
  DeferDiagsRAII(Sema &S, bool DeferDiags)
      : S(S), SavedDeferDiags(S.DeferDiags) {
    S.DeferDiags = DeferDiags;
  }
  ~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
};

/// Whether uncompilable error has occurred. This includes error happens
/// in deferred diagnostics.
bool hasUncompilableErrorOccurred() const;

bool findMacroSpelling(SourceLocation &loc, StringRef name);

/// Get a string to suggest for zero-initialization of a type.
std::string
getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const;
std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;

/// Calls \c Lexer::getLocForEndOfToken()
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = 0);

/// Retrieve the module loader associated with the preprocessor.
ModuleLoader &getModuleLoader() const;

/// Invent a new identifier for parameters of abbreviated templates.
IdentifierInfo *
InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
                                           unsigned Index);

void emitAndClearUnusedLocalTypedefWarnings();

private:
  /// Function or variable declarations to be checked for whether the deferred
  /// diagnostics should be emitted.
  llvm::SmallSetVector<Decl *, 4> DeclsToCheckForDeferredDiags;

public:
// Emit all deferred diagnostics.
void emitDeferredDiags();

enum TUFragmentKind {
  /// The global module fragment, between 'module;' and a module-declaration.
  Global,
  /// A normal translation unit fragment. For a non-module unit, this is the
  /// entire translation unit. Otherwise, it runs from the module-declaration
  /// to the private-module-fragment (if any) or the end of the TU (if not).
  Normal,
  /// The private module fragment, between 'module :private;' and the end of
  /// the translation unit.
  Private
};

void ActOnStartOfTranslationUnit();
void ActOnEndOfTranslationUnit();
void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);

void CheckDelegatingCtorCycles();

Scope *getScopeForContext(DeclContext *Ctx);

void PushFunctionScope();
void PushBlockScope(Scope *BlockScope, BlockDecl *Block);
sema::LambdaScopeInfo *PushLambdaScope();

/// This is used to inform Sema what the current TemplateParameterDepth
/// is during Parsing.  Currently it is used to pass on the depth
/// when parsing generic lambda 'auto' parameters.
void RecordParsingTemplateParameterDepth(unsigned Depth);

void PushCapturedRegionScope(Scope *RegionScope, CapturedDecl *CD,
                             RecordDecl *RD, CapturedRegionKind K,
                             unsigned OpenMPCaptureLevel = 0);

/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
/// time after they've been popped.
class PoppedFunctionScopeDeleter {
  Sema *Self;

public:
  explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
  void operator()(sema::FunctionScopeInfo *Scope) const;
};

using PoppedFunctionScopePtr =
    std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;

PoppedFunctionScopePtr
PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP = nullptr,
                     const Decl *D = nullptr,
                     QualType BlockType = QualType());

sema::FunctionScopeInfo *getCurFunction() const {
  return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
}

sema::FunctionScopeInfo *getEnclosingFunction() const;

void setFunctionHasBranchIntoScope();
void setFunctionHasBranchProtectedScope();
void setFunctionHasIndirectGoto();
void setFunctionHasMustTail();

void PushCompoundScope(bool IsStmtExpr);
void PopCompoundScope();

sema::CompoundScopeInfo &getCurCompoundScope() const;

bool hasAnyUnrecoverableErrorsInThisFunction() const;

/// Retrieve the current block, if any.
sema::BlockScopeInfo *getCurBlock();

/// Get the innermost lambda enclosing the current location, if any. This
/// looks through intervening non-lambda scopes such as local functions and
/// blocks.
sema::LambdaScopeInfo *getEnclosingLambda() const;

/// Retrieve the current lambda scope info, if any.
/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
/// lambda scope info ignoring all inner capturing scopes that are not
/// lambda scopes.
sema::LambdaScopeInfo *
getCurLambda(bool IgnoreNonLambdaCapturingScope = false);

/// Retrieve the current generic lambda info, if any.
sema::LambdaScopeInfo *getCurGenericLambda();

/// Retrieve the current captured region, if any.
sema::CapturedRegionScopeInfo *getCurCapturedRegion();

/// Retrieve the current function, if any, that should be analyzed for
/// potential availability violations.
sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();

/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
SmallVectorImpl<Decl *> &WeakTopLevelDecls() { return WeakTopLevelDecl; }

/// Called before parsing a function declarator belonging to a function
/// declaration.
void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
                                             unsigned TemplateParameterDepth);

/// Called after parsing a function declarator belonging to a function
/// declaration.
void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);

void ActOnComment(SourceRange Comment);

//===--------------------------------------------------------------------===//
// Type Analysis / Processing: SemaType.cpp.
//

QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
                            const DeclSpec *DS = nullptr);
QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
                            const DeclSpec *DS = nullptr);
QualType BuildPointerType(QualType T,
                          SourceLocation Loc, DeclarationName Entity);
QualType BuildReferenceType(QualType T, bool LValueRef,
                            SourceLocation Loc, DeclarationName Entity);
QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                        Expr *ArraySize, unsigned Quals,
                        SourceRange Brackets, DeclarationName Entity);
QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                            SourceLocation AttrLoc);
QualType BuildMatrixType(QualType T, Expr *NumRows, Expr *NumColumns,
                         SourceLocation AttrLoc);

QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
                               SourceLocation AttrLoc);

/// Same as above, but constructs the AddressSpace index if not provided.
QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
                               SourceLocation AttrLoc);

bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);

bool CheckFunctionReturnType(QualType T, SourceLocation Loc);

/// Build a function type.
///
/// This routine checks the function type according to C++ rules and
/// under the assumption that the result type and parameter types have
/// just been instantiated from a template. It therefore duplicates
/// some of the behavior of GetTypeForDeclarator, but in a much
/// simpler form that is only suitable for this narrow use case.
///
/// \param T The return type of the function.
///
/// \param ParamTypes The parameter types of the function. This array
/// will be modified to account for adjustments to the types of the
/// function parameters.
///
/// \param Loc The location of the entity whose type involves this
/// function type or, if there is no such entity, the location of the
/// type that will have function type.
///
/// \param Entity The name of the entity that involves the function
/// type, if known.
///
/// \param EPI Extra information about the function type. Usually this will
/// be taken from an existing function with the same prototype.
///
/// \returns A suitable function type, if there are no errors. The
/// unqualified type will always be a FunctionProtoType.
/// Otherwise, returns a NULL type.
QualType BuildFunctionType(QualType T,
                           MutableArrayRef<QualType> ParamTypes,
                           SourceLocation Loc, DeclarationName Entity,
                           const FunctionProtoType::ExtProtoInfo &EPI);

QualType BuildMemberPointerType(QualType T, QualType Class,
                                SourceLocation Loc,
                                DeclarationName Entity);
QualType BuildBlockPointerType(QualType T,
                               SourceLocation Loc, DeclarationName Entity);
QualType BuildParenType(QualType T);
QualType BuildAtomicType(QualType T, SourceLocation Loc);
QualType BuildReadPipeType(QualType T,
                       SourceLocation Loc);
QualType BuildWritePipeType(QualType T,
                       SourceLocation Loc);
QualType BuildExtIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);

TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);

/// Package the given type and TSI into a ParsedType.
ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
DeclarationNameInfo GetNameForDeclarator(Declarator &D);
DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
static QualType GetTypeFromParser(ParsedType Ty,
                                  TypeSourceInfo **TInfo = nullptr);
CanThrowResult canThrow(const Stmt *E);
/// Determine whether the callee of a particular function call can throw.
/// E, D and Loc are all optional.
static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D,
                                     SourceLocation Loc = SourceLocation());
const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
                                              const FunctionProtoType *FPT);
void UpdateExceptionSpec(FunctionDecl *FD,
                         const FunctionProtoType::ExceptionSpecInfo &ESI);
bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
bool CheckDistantExceptionSpec(QualType T);
bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New);
bool CheckEquivalentExceptionSpec(
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool CheckEquivalentExceptionSpec(
    const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
                              const PartialDiagnostic &NestedDiagID,
                              const PartialDiagnostic &NoteID,
                              const PartialDiagnostic &NoThrowDiagID,
                              const FunctionProtoType *Superset,
                              SourceLocation SuperLoc,
                              const FunctionProtoType *Subset,
                              SourceLocation SubLoc);
bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID,
                             const PartialDiagnostic &NoteID,
                             const FunctionProtoType *Target,
                             SourceLocation TargetLoc,
                             const FunctionProtoType *Source,
                             SourceLocation SourceLoc);

TypeResult ActOnTypeName(Scope *S, Declarator &D);

/// The parser has parsed the context-sensitive type 'instancetype'
/// in an Objective-C message declaration. Return the appropriate type.
ParsedType ActOnObjCInstanceType(SourceLocation Loc);

/// Abstract class used to diagnose incomplete types.
struct TypeDiagnoser {
  TypeDiagnoser() {}

  virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = 0;
  virtual ~TypeDiagnoser() {}
};

static int getPrintable(int I) { return I; }
static unsigned getPrintable(unsigned I) { return I; }
static bool getPrintable(bool B) { return B; }
static const char * getPrintable(const char *S) { return S; }
static StringRef getPrintable(StringRef S) { return S; }
static const std::string &getPrintable(const std::string &S) { return S; }
static const IdentifierInfo *getPrintable(const IdentifierInfo *II) {
  return II;
}
static DeclarationName getPrintable(DeclarationName N) { return N; }
static QualType getPrintable(QualType T) { return T; }
static SourceRange getPrintable(SourceRange R) { return R; }
static SourceRange getPrintable(SourceLocation L) { return L; }
static SourceRange getPrintable(const Expr *E) { return E->getSourceRange(); }
static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange();}

template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
protected:
  unsigned DiagID;
  std::tuple<const Ts &...> Args;

  template <std::size_t... Is>
  void emit(const SemaDiagnosticBuilder &DB,
            std::index_sequence<Is...>) const {
    // Apply all tuple elements to the builder in order.
    bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
    (void)Dummy;
  }

public:
  BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
      : TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
    assert(DiagID != 0 && "no diagnostic for type diagnoser")((void)0);
  }

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
    emit(DB, std::index_sequence_for<Ts...>());
    DB << T;
  }
};

/// Do a check to make sure \p Name looks like a legal argument for the
/// swift_name attribute applied to decl \p D.  Raise a diagnostic if the name
/// is invalid for the given declaration.
///
/// \p AL is used to provide caret diagnostics in case of a malformed name.
///
/// \returns true if the name is a valid swift name for \p D, false otherwise.
bool DiagnoseSwiftName(Decl *D, StringRef Name, SourceLocation Loc,
                       const ParsedAttr &AL, bool IsAsync);

/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
/// For example, a diagnostic with no other parameters would generally have
/// the form "...%select{incomplete|sizeless}0 type %1...".
template <typename... Ts>
class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
public:
  SizelessTypeDiagnoser(unsigned DiagID, const Ts &... Args)
      : BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
    this->emit(DB, std::index_sequence_for<Ts...>());
    DB << T->isSizelessType() << T;
  }
};

enum class CompleteTypeKind {
  /// Apply the normal rules for complete types.  In particular,
  /// treat all sizeless types as incomplete.
  Normal,

  /// Relax the normal rules for complete types so that they include
  /// sizeless built-in types.
  AcceptSizeless,

  // FIXME: Eventually we should flip the default to Normal and opt in
  // to AcceptSizeless rather than opt out of it.
  Default = AcceptSizeless
};

2153private:
/// Methods for marking which expressions involve dereferencing a pointer
/// marked with the 'noderef' attribute. Expressions are checked bottom up as
/// they are parsed, meaning that a noderef pointer may not be accessed. For
/// example, in `&*p` where `p` is a noderef pointer, we will first parse the
/// `*p`, but need to check that `address of` is called on it. This requires
/// keeping a container of all pending expressions and checking if the address
/// of them are eventually taken.
void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
void CheckAddressOfNoDeref(const Expr *E);
void CheckMemberAccessOfNoDeref(const MemberExpr *E);

bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
                             CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);

struct ModuleScope {
  SourceLocation BeginLoc;
  clang::Module *Module = nullptr;
  bool ModuleInterface = false;
  bool ImplicitGlobalModuleFragment = false;
  VisibleModuleSet OuterVisibleModules;
};
/// The modules we're currently parsing.
llvm::SmallVector<ModuleScope, 16> ModuleScopes;

/// Namespace definitions that we will export when they finish.
llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;

/// Get the module whose scope we are currently within.
Module *getCurrentModule() const {
  return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
}

VisibleModuleSet VisibleModules;

2188public:
/// Get the module owning an entity.
Module *getOwningModule(const Decl *Entity) {
  return Entity->getOwningModule();
34
←
Called C++ object pointer is null
}

/// Make a merged definition of an existing hidden definition \p ND
/// visible at the specified location.
void makeMergedDefinitionVisible(NamedDecl *ND);

bool isModuleVisible(const Module *M, bool ModulePrivate = false);

// When loading a non-modular PCH files, this is used to restore module
// visibility.
void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
  VisibleModules.setVisible(Mod, ImportLoc);
}

/// Determine whether a declaration is visible to name lookup.
bool isVisible(const NamedDecl *D) {
  return D->isUnconditionallyVisible() || isVisibleSlow(D);
}

/// Determine whether any declaration of an entity is visible.
bool
hasVisibleDeclaration(const NamedDecl *D,
                      llvm::SmallVectorImpl<Module *> *Modules = nullptr) {
  return isVisible(D) || hasVisibleDeclarationSlow(D, Modules);
}
bool hasVisibleDeclarationSlow(const NamedDecl *D,
                               llvm::SmallVectorImpl<Module *> *Modules);

bool hasVisibleMergedDefinition(NamedDecl *Def);
bool hasMergedDefinitionInCurrentModule(NamedDecl *Def);

/// Determine if \p D and \p Suggested have a structurally compatible
/// layout as described in C11 6.2.7/1.
bool hasStructuralCompatLayout(Decl *D, Decl *Suggested);

/// Determine if \p D has a visible definition. If not, suggest a declaration
/// that should be made visible to expose the definition.
bool hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
                          bool OnlyNeedComplete = false);
bool hasVisibleDefinition(const NamedDecl *D) {
  NamedDecl *Hidden;
  return hasVisibleDefinition(const_cast<NamedDecl*>(D), &Hidden);
}

/// Determine if the template parameter \p D has a visible default argument.
bool
hasVisibleDefaultArgument(const NamedDecl *D,
                          llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is an explicit
/// specialization declaration for a specialization of a template. (For a
/// member specialization, use hasVisibleMemberSpecialization.)
bool hasVisibleExplicitSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is a member
/// specialization declaration (as opposed to an instantiated declaration).
bool hasVisibleMemberSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if \p A and \p B are equivalent internal linkage declarations
/// from different modules, and thus an ambiguity error can be downgraded to
/// an extension warning.
bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
                                            const NamedDecl *B);
void diagnoseEquivalentInternalLinkageDeclarations(
    SourceLocation Loc, const NamedDecl *D,
    ArrayRef<const NamedDecl *> Equiv);

bool isUsualDeallocationFunction(const CXXMethodDecl *FD);

bool isCompleteType(SourceLocation Loc, QualType T,
                    CompleteTypeKind Kind = CompleteTypeKind::Default) {
  return !RequireCompleteTypeImpl(Loc, T, Kind, nullptr);
}
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, unsigned DiagID);

bool RequireCompleteType(SourceLocation Loc, QualType T,
                         TypeDiagnoser &Diagnoser) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, Diagnoser);
}
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, DiagID);
}

template <typename... Ts>
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
                         const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
                              const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
}

/// Get the type of expression E, triggering instantiation to complete the
/// type if necessary -- that is, if the expression refers to a templated
/// static data member of incomplete array type.
///
/// May still return an incomplete type if instantiation was not possible or
/// if the type is incomplete for a different reason. Use
/// RequireCompleteExprType instead if a diagnostic is expected for an
/// incomplete expression type.
QualType getCompletedType(Expr *E);

void completeExprArrayBound(Expr *E);
bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
                             TypeDiagnoser &Diagnoser);
bool RequireCompleteExprType(Expr *E, unsigned DiagID);

template <typename... Ts>
bool RequireCompleteExprType(Expr *E, unsigned DiagID, const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedExprType(Expr *E, unsigned DiagID,
                                  const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
}

bool RequireLiteralType(SourceLocation Loc, QualType T,
                        TypeDiagnoser &Diagnoser);
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);

template <typename... Ts>
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
                        const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireLiteralType(Loc, T, Diagnoser);
}

QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
                           const CXXScopeSpec &SS, QualType T,
                           TagDecl *OwnedTagDecl = nullptr);

QualType getDecltypeForParenthesizedExpr(Expr *E);
QualType BuildTypeofExprType(Expr *E, SourceLocation Loc);
/// If AsUnevaluated is false, E is treated as though it were an evaluated
/// context, such as when building a type for decltype(auto).
QualType BuildDecltypeType(Expr *E, SourceLocation Loc,
                           bool AsUnevaluated = true);
QualType BuildUnaryTransformType(QualType BaseType,
                                 UnaryTransformType::UTTKind UKind,
                                 SourceLocation Loc);

//===--------------------------------------------------------------------===//
// Symbol table / Decl tracking callbacks: SemaDecl.cpp.
//

struct SkipBodyInfo {
  SkipBodyInfo()
      : ShouldSkip(false), CheckSameAsPrevious(false), Previous(nullptr),
        New(nullptr) {}
  bool ShouldSkip;
  bool CheckSameAsPrevious;
  NamedDecl *Previous;
  NamedDecl *New;
};

DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = nullptr);

void DiagnoseUseOfUnimplementedSelectors();

bool isSimpleTypeSpecifier(tok::TokenKind Kind) const;

ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                       Scope *S, CXXScopeSpec *SS = nullptr,
                       bool isClassName = false, bool HasTrailingDot = false,
                       ParsedType ObjectType = nullptr,
                       bool IsCtorOrDtorName = false,
                       bool WantNontrivialTypeSourceInfo = false,
                       bool IsClassTemplateDeductionContext = true,
                       IdentifierInfo **CorrectedII = nullptr);
TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
bool isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S);
void DiagnoseUnknownTypeName(IdentifierInfo *&II,
                             SourceLocation IILoc,
                             Scope *S,
                             CXXScopeSpec *SS,
                             ParsedType &SuggestedType,
                             bool IsTemplateName = false);

/// Attempt to behave like MSVC in situations where lookup of an unqualified
/// type name has failed in a dependent context. In these situations, we
/// automatically form a DependentTypeName that will retry lookup in a related
/// scope during instantiation.
ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
                                    SourceLocation NameLoc,
                                    bool IsTemplateTypeArg);

/// Describes the result of the name lookup and resolution performed
/// by \c ClassifyName().
enum NameClassificationKind {
  /// This name is not a type or template in this context, but might be
  /// something else.
  NC_Unknown,
  /// Classification failed; an error has been produced.
  NC_Error,
  /// The name has been typo-corrected to a keyword.
  NC_Keyword,
  /// The name was classified as a type.
  NC_Type,
  /// The name was classified as a specific non-type, non-template
  /// declaration. ActOnNameClassifiedAsNonType should be called to
  /// convert the declaration to an expression.
  NC_NonType,
  /// The name was classified as an ADL-only function name.
  /// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
  /// result to an expression.
  NC_UndeclaredNonType,
  /// The name denotes a member of a dependent type that could not be
  /// resolved. ActOnNameClassifiedAsDependentNonType should be called to
  /// convert the result to an expression.
  NC_DependentNonType,
  /// The name was classified as an overload set, and an expression
  /// representing that overload set has been formed.
  /// ActOnNameClassifiedAsOverloadSet should be called to form a suitable
  /// expression referencing the overload set.
  NC_OverloadSet,
  /// The name was classified as a template whose specializations are types.
  NC_TypeTemplate,
  /// The name was classified as a variable template name.
  NC_VarTemplate,
  /// The name was classified as a function template name.
  NC_FunctionTemplate,
  /// The name was classified as an ADL-only function template name.
  NC_UndeclaredTemplate,
  /// The name was classified as a concept name.
  NC_Concept,
};

class NameClassification {
  NameClassificationKind Kind;
  union {
    ExprResult Expr;
    NamedDecl *NonTypeDecl;
    TemplateName Template;
    ParsedType Type;
  };

  explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}

public:
  NameClassification(ParsedType Type) : Kind(NC_Type), Type(Type) {}

  NameClassification(const IdentifierInfo *Keyword) : Kind(NC_Keyword) {}

  static NameClassification Error() {
    return NameClassification(NC_Error);
  }

  static NameClassification Unknown() {
    return NameClassification(NC_Unknown);
  }

  static NameClassification OverloadSet(ExprResult E) {
    NameClassification Result(NC_OverloadSet);
    Result.Expr = E;
    return Result;
  }

  static NameClassification NonType(NamedDecl *D) {
    NameClassification Result(NC_NonType);
    Result.NonTypeDecl = D;
    return Result;
  }

  static NameClassification UndeclaredNonType() {
    return NameClassification(NC_UndeclaredNonType);
  }

  static NameClassification DependentNonType() {
    return NameClassification(NC_DependentNonType);
  }

  static NameClassification TypeTemplate(TemplateName Name) {
    NameClassification Result(NC_TypeTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification VarTemplate(TemplateName Name) {
    NameClassification Result(NC_VarTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification FunctionTemplate(TemplateName Name) {
    NameClassification Result(NC_FunctionTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification Concept(TemplateName Name) {
    NameClassification Result(NC_Concept);
    Result.Template = Name;
    return Result;
  }

  static NameClassification UndeclaredTemplate(TemplateName Name) {
    NameClassification Result(NC_UndeclaredTemplate);
    Result.Template = Name;
    return Result;
  }

  NameClassificationKind getKind() const { return Kind; }

  ExprResult getExpression() const {
    assert(Kind == NC_OverloadSet)((void)0);
    return Expr;
  }

  ParsedType getType() const {
    assert(Kind == NC_Type)((void)0);
    return Type;
  }

  NamedDecl *getNonTypeDecl() const {
    assert(Kind == NC_NonType)((void)0);
    return NonTypeDecl;
  }

  TemplateName getTemplateName() const {
    assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate ||((void)0)
           Kind == NC_VarTemplate || Kind == NC_Concept ||((void)0)
           Kind == NC_UndeclaredTemplate)((void)0);
    return Template;
  }

  TemplateNameKind getTemplateNameKind() const {
    switch (Kind) {
    case NC_TypeTemplate:
      return TNK_Type_template;
    case NC_FunctionTemplate:
      return TNK_Function_template;
    case NC_VarTemplate:
      return TNK_Var_template;
    case NC_Concept:
      return TNK_Concept_template;
    case NC_UndeclaredTemplate:
      return TNK_Undeclared_template;
    default:
      llvm_unreachable("unsupported name classification.")__builtin_unreachable();
    }
  }
};

/// Perform name lookup on the given name, classifying it based on
/// the results of name lookup and the following token.
///
/// This routine is used by the parser to resolve identifiers and help direct
/// parsing. When the identifier cannot be found, this routine will attempt
/// to correct the typo and classify based on the resulting name.
///
/// \param S The scope in which we're performing name lookup.
///
/// \param SS The nested-name-specifier that precedes the name.
///
/// \param Name The identifier. If typo correction finds an alternative name,
/// this pointer parameter will be updated accordingly.
///
/// \param NameLoc The location of the identifier.
///
/// \param NextToken The token following the identifier. Used to help
/// disambiguate the name.
///
/// \param CCC The correction callback, if typo correction is desired.
NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
                                IdentifierInfo *&Name, SourceLocation NameLoc,
                                const Token &NextToken,
                                CorrectionCandidateCallback *CCC = nullptr);

/// Act on the result of classifying a name as an undeclared (ADL-only)
/// non-type declaration.
ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
                                                  SourceLocation NameLoc);
/// Act on the result of classifying a name as an undeclared member of a
/// dependent base class.
ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
                                                 IdentifierInfo *Name,
                                                 SourceLocation NameLoc,
                                                 bool IsAddressOfOperand);
/// Act on the result of classifying a name as a specific non-type
/// declaration.
ExprResult ActOnNameClassifiedAsNonType(Scope *S, const CXXScopeSpec &SS,
                                        NamedDecl *Found,
                                        SourceLocation NameLoc,
                                        const Token &NextToken);
/// Act on the result of classifying a name as an overload set.
ExprResult ActOnNameClassifiedAsOverloadSet(Scope *S, Expr *OverloadSet);

/// Describes the detailed kind of a template name. Used in diagnostics.
enum class TemplateNameKindForDiagnostics {
  ClassTemplate,
  FunctionTemplate,
  VarTemplate,
  AliasTemplate,
  TemplateTemplateParam,
  Concept,
  DependentTemplate
};
TemplateNameKindForDiagnostics
getTemplateNameKindForDiagnostics(TemplateName Name);

/// Determine whether it's plausible that E was intended to be a
/// template-name.
bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
  if (!getLangOpts().CPlusPlus || E.isInvalid())
    return false;
  Dependent = false;
  if (auto *DRE = dyn_cast<DeclRefExpr>(E.get()))
    return !DRE->hasExplicitTemplateArgs();
  if (auto *ME = dyn_cast<MemberExpr>(E.get()))
    return !ME->hasExplicitTemplateArgs();
  Dependent = true;
  if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(E.get()))
    return !DSDRE->hasExplicitTemplateArgs();
  if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(E.get()))
    return !DSME->hasExplicitTemplateArgs();
  // Any additional cases recognized here should also be handled by
  // diagnoseExprIntendedAsTemplateName.
  return false;
}
void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
                                        SourceLocation Less,
                                        SourceLocation Greater);

void warnOnReservedIdentifier(const NamedDecl *D);

Decl *ActOnDeclarator(Scope *S, Declarator &D);

NamedDecl *HandleDeclarator(Scope *S, Declarator &D,
                            MultiTemplateParamsArg TemplateParameterLists);
bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo,
                                     QualType &T, SourceLocation Loc,
                                     unsigned FailedFoldDiagID);
void RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S);
bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                  DeclarationName Name, SourceLocation Loc,
                                  bool IsTemplateId);
void
diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                          SourceLocation FallbackLoc,
                          SourceLocation ConstQualLoc = SourceLocation(),
                          SourceLocation VolatileQualLoc = SourceLocation(),
                          SourceLocation RestrictQualLoc = SourceLocation(),
                          SourceLocation AtomicQualLoc = SourceLocation(),
                          SourceLocation UnalignedQualLoc = SourceLocation());

static bool adjustContextForLocalExternDecl(DeclContext *&DC);
void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
NamedDecl *getShadowedDeclaration(const TypedefNameDecl *D,
                                  const LookupResult &R);
NamedDecl *getShadowedDeclaration(const VarDecl *D, const LookupResult &R);
NamedDecl *getShadowedDeclaration(const BindingDecl *D,
                                  const LookupResult &R);
void CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
                 const LookupResult &R);
void CheckShadow(Scope *S, VarDecl *D);

/// Warn if 'E', which is an expression that is about to be modified, refers
/// to a shadowing declaration.
void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);

void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);

2669private:
/// Map of current shadowing declarations to shadowed declarations. Warn if
/// it looks like the user is trying to modify the shadowing declaration.
llvm::DenseMap<const NamedDecl *, const NamedDecl *> ShadowingDecls;

2674public:
void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
void handleTagNumbering(const TagDecl *Tag, Scope *TagScope);
void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
                                  TypedefNameDecl *NewTD);
void CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *D);
NamedDecl* ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                  TypeSourceInfo *TInfo,
                                  LookupResult &Previous);
NamedDecl* ActOnTypedefNameDecl(Scope* S, DeclContext* DC, TypedefNameDecl *D,
                                LookupResult &Previous, bool &Redeclaration);
NamedDecl *ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope,
                                   ArrayRef<BindingDecl *> Bindings = None);
NamedDecl *
ActOnDecompositionDeclarator(Scope *S, Declarator &D,
                             MultiTemplateParamsArg TemplateParamLists);
// Returns true if the variable declaration is a redeclaration
bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
void CheckVariableDeclarationType(VarDecl *NewVD);
bool DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                   Expr *Init);
void CheckCompleteVariableDeclaration(VarDecl *VD);
void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);

NamedDecl* ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope);
bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);

enum class CheckConstexprKind {
  /// Diagnose issues that are non-constant or that are extensions.
  Diagnose,
  /// Identify whether this function satisfies the formal rules for constexpr
  /// functions in the current lanugage mode (with no extensions).
  CheckValid
};

bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
                                      CheckConstexprKind Kind);

void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
void FindHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
void NoteHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
// Returns true if the function declaration is a redeclaration
bool CheckFunctionDeclaration(Scope *S,
                              FunctionDecl *NewFD, LookupResult &Previous,
                              bool IsMemberSpecialization);
bool shouldLinkDependentDeclWithPrevious(Decl *D, Decl *OldDecl);
bool canFullyTypeCheckRedeclaration(ValueDecl *NewD, ValueDecl *OldD,
                                    QualType NewT, QualType OldT);
void CheckMain(FunctionDecl *FD, const DeclSpec &D);
void CheckMSVCRTEntryPoint(FunctionDecl *FD);
Attr *getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD,
                                                 bool IsDefinition);
void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                        SourceLocation Loc,
                                        QualType T);
ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                            SourceLocation NameLoc, IdentifierInfo *Name,
                            QualType T, TypeSourceInfo *TSInfo,
                            StorageClass SC);
void ActOnParamDefaultArgument(Decl *param,
                               SourceLocation EqualLoc,
                               Expr *defarg);
void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
                                       SourceLocation ArgLoc);
void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc);
ExprResult ConvertParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                                       SourceLocation EqualLoc);
void SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                             SourceLocation EqualLoc);

// Contexts where using non-trivial C union types can be disallowed. This is
// passed to err_non_trivial_c_union_in_invalid_context.
enum NonTrivialCUnionContext {
  // Function parameter.
  NTCUC_FunctionParam,
  // Function return.
  NTCUC_FunctionReturn,
  // Default-initialized object.
  NTCUC_DefaultInitializedObject,
  // Variable with automatic storage duration.
  NTCUC_AutoVar,
  // Initializer expression that might copy from another object.
  NTCUC_CopyInit,
  // Assignment.
  NTCUC_Assignment,
  // Compound literal.
  NTCUC_CompoundLiteral,
  // Block capture.
  NTCUC_BlockCapture,
  // lvalue-to-rvalue conversion of volatile type.
  NTCUC_LValueToRValueVolatile,
};

/// Emit diagnostics if the initializer or any of its explicit or
/// implicitly-generated subexpressions require copying or
/// default-initializing a type that is or contains a C union type that is
/// non-trivial to copy or default-initialize.
void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);

// These flags are passed to checkNonTrivialCUnion.
enum NonTrivialCUnionKind {
  NTCUK_Init = 0x1,
  NTCUK_Destruct = 0x2,
  NTCUK_Copy = 0x4,
};

/// Emit diagnostics if a non-trivial C union type or a struct that contains
/// a non-trivial C union is used in an invalid context.
void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
                           NonTrivialCUnionContext UseContext,
                           unsigned NonTrivialKind);

void AddInitializerToDecl(Decl *dcl, Expr *init, bool DirectInit);
void ActOnUninitializedDecl(Decl *dcl);
void ActOnInitializerError(Decl *Dcl);

void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
void ActOnCXXForRangeDecl(Decl *D);
StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
                                      IdentifierInfo *Ident,
                                      ParsedAttributes &Attrs,
                                      SourceLocation AttrEnd);
void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc);
void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
void CheckStaticLocalForDllExport(VarDecl *VD);
void FinalizeDeclaration(Decl *D);
DeclGroupPtrTy FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                       ArrayRef<Decl *> Group);
DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);

/// Should be called on all declarations that might have attached
/// documentation comments.
void ActOnDocumentableDecl(Decl *D);
void ActOnDocumentableDecls(ArrayRef<Decl *> Group);

void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                     SourceLocation LocAfterDecls);
void CheckForFunctionRedefinition(
    FunctionDecl *FD, const FunctionDecl *EffectiveDefinition = nullptr,
    SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D,
                              MultiTemplateParamsArg TemplateParamLists,
                              SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D,
                              SkipBodyInfo *SkipBody = nullptr);
void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);
bool isObjCMethodDecl(Decl *D) {
  return D && isa<ObjCMethodDecl>(D);
}

/// Determine whether we can delay parsing the body of a function or
/// function template until it is used, assuming we don't care about emitting
/// code for that function.
///
/// This will be \c false if we may need the body of the function in the
/// middle of parsing an expression (where it's impractical to switch to
/// parsing a different function), for instance, if it's constexpr in C++11
/// or has an 'auto' return type in C++14. These cases are essentially bugs.
bool canDelayFunctionBody(const Declarator &D);

/// Determine whether we can skip parsing the body of a function
/// definition, assuming we don't care about analyzing its body or emitting
/// code for that function.
///
/// This will be \c false only if we may need the body of the function in
/// order to parse the rest of the program (for instance, if it is
/// \c constexpr in C++11 or has an 'auto' return type in C++14).
bool canSkipFunctionBody(Decl *D);

void computeNRVO(Stmt *Body, sema::FunctionScopeInfo *Scope);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body, bool IsInstantiation);
Decl *ActOnSkippedFunctionBody(Decl *Decl);
void ActOnFinishInlineFunctionDef(FunctionDecl *D);

/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
/// attribute for which parsing is delayed.
void ActOnFinishDelayedAttribute(Scope *S, Decl *D, ParsedAttributes &Attrs);

/// Diagnose any unused parameters in the given sequence of
/// ParmVarDecl pointers.
void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);

/// Diagnose whether the size of parameters or return value of a
/// function or obj-c method definition is pass-by-value and larger than a
/// specified threshold.
void
DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
                                       QualType ReturnTy, NamedDecl *D);

void DiagnoseInvalidJumps(Stmt *Body);
Decl *ActOnFileScopeAsmDecl(Expr *expr,
                            SourceLocation AsmLoc,
                            SourceLocation RParenLoc);

/// Handle a C++11 empty-declaration and attribute-declaration.
Decl *ActOnEmptyDeclaration(Scope *S, const ParsedAttributesView &AttrList,
                            SourceLocation SemiLoc);

enum class ModuleDeclKind {
  Interface,      ///< 'export module X;'
  Implementation, ///< 'module X;'
};

/// The parser has processed a module-declaration that begins the definition
/// of a module interface or implementation.
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
                               SourceLocation ModuleLoc, ModuleDeclKind MDK,
                               ModuleIdPath Path, bool IsFirstDecl);

/// The parser has processed a global-module-fragment declaration that begins
/// the definition of the global module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);

/// The parser has processed a private-module-fragment declaration that begins
/// the definition of the private module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
/// \param PrivateLoc The location of the 'private' keyword.
DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
                                              SourceLocation PrivateLoc);

/// The parser has processed a module import declaration.
///
/// \param StartLoc The location of the first token in the declaration. This
///        could be the location of an '@', 'export', or 'import'.
/// \param ExportLoc The location of the 'export' keyword, if any.
/// \param ImportLoc The location of the 'import' keyword.
/// \param Path The module access path.
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, ModuleIdPath Path);
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, Module *M,
                             ModuleIdPath Path = {});

/// The parser has processed a module import translated from a
/// #include or similar preprocessing directive.
void ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);

/// The parsed has entered a submodule.
void ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
/// The parser has left a submodule.
void ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod);

/// Create an implicit import of the given module at the given
/// source location, for error recovery, if possible.
///
/// This routine is typically used when an entity found by name lookup
/// is actually hidden within a module that we know about but the user
/// has forgotten to import.
void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
                                                Module *Mod);

/// Kinds of missing import. Note, the values of these enumerators correspond
/// to %select values in diagnostics.
enum class MissingImportKind {
  Declaration,
  Definition,
  DefaultArgument,
  ExplicitSpecialization,
  PartialSpecialization
};

/// Diagnose that the specified declaration needs to be visible but
/// isn't, and suggest a module import that would resolve the problem.
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           MissingImportKind MIK, bool Recover = true);
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           SourceLocation DeclLoc, ArrayRef<Module *> Modules,
                           MissingImportKind MIK, bool Recover);

Decl *ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
                           SourceLocation LBraceLoc);
Decl *ActOnFinishExportDecl(Scope *S, Decl *ExportDecl,
                            SourceLocation RBraceLoc);

/// We've found a use of a templated declaration that would trigger an
/// implicit instantiation. Check that any relevant explicit specializations
/// and partial specializations are visible, and diagnose if not.
void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);

/// Retrieve a suitable printing policy for diagnostics.
PrintingPolicy getPrintingPolicy() const {
  return getPrintingPolicy(Context, PP);
}

/// Retrieve a suitable printing policy for diagnostics.
static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
                                        const Preprocessor &PP);

/// Scope actions.
void ActOnPopScope(SourceLocation Loc, Scope *S);
void ActOnTranslationUnitScope(Scope *S);

Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 RecordDecl *&AnonRecord);
Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 MultiTemplateParamsArg TemplateParams,
                                 bool IsExplicitInstantiation,
                                 RecordDecl *&AnonRecord);

Decl *BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                  AccessSpecifier AS,
                                  RecordDecl *Record,
                                  const PrintingPolicy &Policy);

Decl *BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                     RecordDecl *Record);

/// Common ways to introduce type names without a tag for use in diagnostics.
/// Keep in sync with err_tag_reference_non_tag.
enum NonTagKind {
  NTK_NonStruct,
  NTK_NonClass,
  NTK_NonUnion,
  NTK_NonEnum,
  NTK_Typedef,
  NTK_TypeAlias,
  NTK_Template,
  NTK_TypeAliasTemplate,
  NTK_TemplateTemplateArgument,
};

/// Given a non-tag type declaration, returns an enum useful for indicating
/// what kind of non-tag type this is.
NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);

bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                  TagTypeKind NewTag, bool isDefinition,
                                  SourceLocation NewTagLoc,
                                  const IdentifierInfo *Name);

enum TagUseKind {
  TUK_Reference,   // Reference to a tag:  'struct foo *X;'
  TUK_Declaration, // Fwd decl of a tag:   'struct foo;'
  TUK_Definition,  // Definition of a tag: 'struct foo { int X; } Y;'
  TUK_Friend       // Friend declaration:  'friend struct foo;'
};

Decl *ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
               SourceLocation KWLoc, CXXScopeSpec &SS, IdentifierInfo *Name,
               SourceLocation NameLoc, const ParsedAttributesView &Attr,
               AccessSpecifier AS, SourceLocation ModulePrivateLoc,
               MultiTemplateParamsArg TemplateParameterLists, bool &OwnedDecl,
               bool &IsDependent, SourceLocation ScopedEnumKWLoc,
               bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
               bool IsTypeSpecifier, bool IsTemplateParamOrArg,
               SkipBodyInfo *SkipBody = nullptr);

Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                              unsigned TagSpec, SourceLocation TagLoc,
                              CXXScopeSpec &SS, IdentifierInfo *Name,
                              SourceLocation NameLoc,
                              const ParsedAttributesView &Attr,
                              MultiTemplateParamsArg TempParamLists);

TypeResult ActOnDependentTag(Scope *S,
                             unsigned TagSpec,
                             TagUseKind TUK,
                             const CXXScopeSpec &SS,
                             IdentifierInfo *Name,
                             SourceLocation TagLoc,
                             SourceLocation NameLoc);

void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
               IdentifierInfo *ClassName,
               SmallVectorImpl<Decl *> &Decls);
Decl *ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                 Declarator &D, Expr *BitfieldWidth);

FieldDecl *HandleField(Scope *S, RecordDecl *TagD, SourceLocation DeclStart,
                       Declarator &D, Expr *BitfieldWidth,
                       InClassInitStyle InitStyle,
                       AccessSpecifier AS);
MSPropertyDecl *HandleMSProperty(Scope *S, RecordDecl *TagD,
                                 SourceLocation DeclStart, Declarator &D,
                                 Expr *BitfieldWidth,
                                 InClassInitStyle InitStyle,
                                 AccessSpecifier AS,
                                 const ParsedAttr &MSPropertyAttr);

FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
                          TypeSourceInfo *TInfo,
                          RecordDecl *Record, SourceLocation Loc,
                          bool Mutable, Expr *BitfieldWidth,
                          InClassInitStyle InitStyle,
                          SourceLocation TSSL,
                          AccessSpecifier AS, NamedDecl *PrevDecl,
                          Declarator *D = nullptr);

bool CheckNontrivialField(FieldDecl *FD);
void DiagnoseNontrivial(const CXXRecordDecl *Record, CXXSpecialMember CSM);

enum TrivialABIHandling {
  /// The triviality of a method unaffected by "trivial_abi".
  TAH_IgnoreTrivialABI,

  /// The triviality of a method affected by "trivial_abi".
  TAH_ConsiderTrivialABI
};

bool SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
                            TrivialABIHandling TAH = TAH_IgnoreTrivialABI,
                            bool Diagnose = false);

/// For a defaulted function, the kind of defaulted function that it is.
class DefaultedFunctionKind {
  CXXSpecialMember SpecialMember : 8;
  DefaultedComparisonKind Comparison : 8;

public:
  DefaultedFunctionKind()
      : SpecialMember(CXXInvalid), Comparison(DefaultedComparisonKind::None) {
  }
  DefaultedFunctionKind(CXXSpecialMember CSM)
      : SpecialMember(CSM), Comparison(DefaultedComparisonKind::None) {}
  DefaultedFunctionKind(DefaultedComparisonKind Comp)
      : SpecialMember(CXXInvalid), Comparison(Comp) {}

  bool isSpecialMember() const { return SpecialMember != CXXInvalid; }
  bool isComparison() const {
    return Comparison != DefaultedComparisonKind::None;
  }

  explicit operator bool() const {
    return isSpecialMember() || isComparison();
  }

  CXXSpecialMember asSpecialMember() const { return SpecialMember; }
  DefaultedComparisonKind asComparison() const { return Comparison; }

  /// Get the index of this function kind for use in diagnostics.
  unsigned getDiagnosticIndex() const {
    static_assert(CXXInvalid > CXXDestructor,
                  "invalid should have highest index");
    static_assert((unsigned)DefaultedComparisonKind::None == 0,
                  "none should be equal to zero");
    return SpecialMember + (unsigned)Comparison;
  }
};

DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);

CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD) {
  return getDefaultedFunctionKind(MD).asSpecialMember();
}
DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl *FD) {
  return getDefaultedFunctionKind(FD).asComparison();
}

void ActOnLastBitfield(SourceLocation DeclStart,
                       SmallVectorImpl<Decl *> &AllIvarDecls);
Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
                Declarator &D, Expr *BitfieldWidth,
                tok::ObjCKeywordKind visibility);

// This is used for both record definitions and ObjC interface declarations.
void ActOnFields(Scope *S, SourceLocation RecLoc, Decl *TagDecl,
                 ArrayRef<Decl *> Fields, SourceLocation LBrac,
                 SourceLocation RBrac, const ParsedAttributesView &AttrList);

/// ActOnTagStartDefinition - Invoked when we have entered the
/// scope of a tag's definition (e.g., for an enumeration, class,
/// struct, or union).
void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);

/// Perform ODR-like check for C/ObjC when merging tag types from modules.
/// Differently from C++, actually parse the body and reject / error out
/// in case of a structural mismatch.
bool ActOnDuplicateDefinition(DeclSpec &DS, Decl *Prev,
                              SkipBodyInfo &SkipBody);

typedef void *SkippedDefinitionContext;

/// Invoked when we enter a tag definition that we're skipping.
SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope *S, Decl *TD);

Decl *ActOnObjCContainerStartDefinition(Decl *IDecl);

/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
/// C++ record definition's base-specifiers clause and are starting its
/// member declarations.
void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                     SourceLocation FinalLoc,
                                     bool IsFinalSpelledSealed,
                                     bool IsAbstract,
                                     SourceLocation LBraceLoc);

/// ActOnTagFinishDefinition - Invoked once we have finished parsing
/// the definition of a tag (enumeration, class, struct, or union).
void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
                              SourceRange BraceRange);

void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);

void ActOnObjCContainerFinishDefinition();

/// Invoked when we must temporarily exit the objective-c container
/// scope for parsing/looking-up C constructs.
///
/// Must be followed by a call to \see ActOnObjCReenterContainerContext
void ActOnObjCTemporaryExitContainerContext(DeclContext *DC);
void ActOnObjCReenterContainerContext(DeclContext *DC);

/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
/// error parsing the definition of a tag.
void ActOnTagDefinitionError(Scope *S, Decl *TagDecl);

EnumConstantDecl *CheckEnumConstant(EnumDecl *Enum,
                                    EnumConstantDecl *LastEnumConst,
                                    SourceLocation IdLoc,
                                    IdentifierInfo *Id,
                                    Expr *val);
bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                            QualType EnumUnderlyingTy, bool IsFixed,
                            const EnumDecl *Prev);

/// Determine whether the body of an anonymous enumeration should be skipped.
/// \param II The name of the first enumerator.
SkipBodyInfo shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                    SourceLocation IILoc);

Decl *ActOnEnumConstant(Scope *S, Decl *EnumDecl, Decl *LastEnumConstant,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        const ParsedAttributesView &Attrs,
                        SourceLocation EqualLoc, Expr *Val);
void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
                   Decl *EnumDecl, ArrayRef<Decl *> Elements, Scope *S,
                   const ParsedAttributesView &Attr);

/// Set the current declaration context until it gets popped.
void PushDeclContext(Scope *S, DeclContext *DC);
void PopDeclContext();

/// EnterDeclaratorContext - Used when we must lookup names in the context
/// of a declarator's nested name specifier.
void EnterDeclaratorContext(Scope *S, DeclContext *DC);
void ExitDeclaratorContext(Scope *S);

/// Enter a template parameter scope, after it's been associated with a particular
/// DeclContext. Causes lookup within the scope to chain through enclosing contexts
/// in the correct order.
void EnterTemplatedContext(Scope *S, DeclContext *DC);

/// Push the parameters of D, which must be a function, into scope.
void ActOnReenterFunctionContext(Scope* S, Decl* D);
void ActOnExitFunctionContext();

DeclContext *getFunctionLevelDeclContext();

/// getCurFunctionDecl - If inside of a function body, this returns a pointer
/// to the function decl for the function being parsed.  If we're currently
/// in a 'block', this returns the containing context.
FunctionDecl *getCurFunctionDecl();

/// getCurMethodDecl - If inside of a method body, this returns a pointer to
/// the method decl for the method being parsed.  If we're currently
/// in a 'block', this returns the containing context.
ObjCMethodDecl *getCurMethodDecl();

/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
/// or C function we're in, otherwise return null.  If we're currently
/// in a 'block', this returns the containing context.
NamedDecl *getCurFunctionOrMethodDecl();

/// Add this decl to the scope shadowed decl chains.
void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);

/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
/// true if 'D' belongs to the given declaration context.
///
/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
///        enclosing namespace set of the context, rather than contained
///        directly within it.
bool isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S = nullptr,
                   bool AllowInlineNamespace = false);

/// Finds the scope corresponding to the given decl context, if it
/// happens to be an enclosing scope.  Otherwise return NULL.
static Scope *getScopeForDeclContext(Scope *S, DeclContext *DC);

/// Subroutines of ActOnDeclarator().
TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                              TypeSourceInfo *TInfo);
bool isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New);

/// Describes the kind of merge to perform for availability
/// attributes (including "deprecated", "unavailable", and "availability").
enum AvailabilityMergeKind {
  /// Don't merge availability attributes at all.
  AMK_None,
  /// Merge availability attributes for a redeclaration, which requires
  /// an exact match.
  AMK_Redeclaration,
  /// Merge availability attributes for an override, which requires
  /// an exact match or a weakening of constraints.
  AMK_Override,
  /// Merge availability attributes for an implementation of
  /// a protocol requirement.
  AMK_ProtocolImplementation,
  /// Merge availability attributes for an implementation of
  /// an optional protocol requirement.
  AMK_OptionalProtocolImplementation
};

/// Describes the kind of priority given to an availability attribute.
///
/// The sum of priorities deteremines the final priority of the attribute.
/// The final priority determines how the attribute will be merged.
/// An attribute with a lower priority will always remove higher priority
/// attributes for the specified platform when it is being applied. An
/// attribute with a higher priority will not be applied if the declaration
/// already has an availability attribute with a lower priority for the
/// specified platform. The final prirority values are not expected to match
/// the values in this enumeration, but instead should be treated as a plain
/// integer value. This enumeration just names the priority weights that are
/// used to calculate that final vaue.
enum AvailabilityPriority : int {
  /// The availability attribute was specified explicitly next to the
  /// declaration.
  AP_Explicit = 0,

  /// The availability attribute was applied using '#pragma clang attribute'.
  AP_PragmaClangAttribute = 1,

  /// The availability attribute for a specific platform was inferred from
  /// an availability attribute for another platform.
  AP_InferredFromOtherPlatform = 2
};

/// Attribute merging methods. Return true if a new attribute was added.
AvailabilityAttr *
mergeAvailabilityAttr(NamedDecl *D, const AttributeCommonInfo &CI,
                      IdentifierInfo *Platform, bool Implicit,
                      VersionTuple Introduced, VersionTuple Deprecated,
                      VersionTuple Obsoleted, bool IsUnavailable,
                      StringRef Message, bool IsStrict, StringRef Replacement,
                      AvailabilityMergeKind AMK, int Priority);
TypeVisibilityAttr *
mergeTypeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                        TypeVisibilityAttr::VisibilityType Vis);
VisibilityAttr *mergeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                                    VisibilityAttr::VisibilityType Vis);
UuidAttr *mergeUuidAttr(Decl *D, const AttributeCommonInfo &CI,
                        StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
DLLImportAttr *mergeDLLImportAttr(Decl *D, const AttributeCommonInfo &CI);
DLLExportAttr *mergeDLLExportAttr(Decl *D, const AttributeCommonInfo &CI);
MSInheritanceAttr *mergeMSInheritanceAttr(Decl *D,
                                          const AttributeCommonInfo &CI,
                                          bool BestCase,
                                          MSInheritanceModel Model);
FormatAttr *mergeFormatAttr(Decl *D, const AttributeCommonInfo &CI,
                            IdentifierInfo *Format, int FormatIdx,
                            int FirstArg);
SectionAttr *mergeSectionAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
CodeSegAttr *mergeCodeSegAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
AlwaysInlineAttr *mergeAlwaysInlineAttr(Decl *D,
                                        const AttributeCommonInfo &CI,
                                        const IdentifierInfo *Ident);
MinSizeAttr *mergeMinSizeAttr(Decl *D, const AttributeCommonInfo &CI);
SwiftNameAttr *mergeSwiftNameAttr(Decl *D, const SwiftNameAttr &SNA,
                                  StringRef Name);
OptimizeNoneAttr *mergeOptimizeNoneAttr(Decl *D,
                                        const AttributeCommonInfo &CI);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D, const ParsedAttr &AL);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D,
                                              const InternalLinkageAttr &AL);
WebAssemblyImportNameAttr *mergeImportNameAttr(
    Decl *D, const WebAssemblyImportNameAttr &AL);
WebAssemblyImportModuleAttr *mergeImportModuleAttr(
    Decl *D, const WebAssemblyImportModuleAttr &AL);
EnforceTCBAttr *mergeEnforceTCBAttr(Decl *D, const EnforceTCBAttr &AL);
EnforceTCBLeafAttr *mergeEnforceTCBLeafAttr(Decl *D,
                                            const EnforceTCBLeafAttr &AL);

void mergeDeclAttributes(NamedDecl *New, Decl *Old,
                         AvailabilityMergeKind AMK = AMK_Redeclaration);
void MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
                          LookupResult &OldDecls);
bool MergeFunctionDecl(FunctionDecl *New, NamedDecl *&Old, Scope *S,
                       bool MergeTypeWithOld);
bool MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                  Scope *S, bool MergeTypeWithOld);
void mergeObjCMethodDecls(ObjCMethodDecl *New, ObjCMethodDecl *Old);
void MergeVarDecl(VarDecl *New, LookupResult &Previous);
void MergeVarDeclTypes(VarDecl *New, VarDecl *Old, bool MergeTypeWithOld);
void MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old);
bool checkVarDeclRedefinition(VarDecl *OldDefn, VarDecl *NewDefn);
void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
bool MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old, Scope *S);

// AssignmentAction - This is used by all the assignment diagnostic functions
// to represent what is actually causing the operation
enum AssignmentAction {
  AA_Assigning,
  AA_Passing,
  AA_Returning,
  AA_Converting,
  AA_Initializing,
  AA_Sending,
  AA_Casting,
  AA_Passing_CFAudited
};

/// C++ Overloading.
enum OverloadKind {
  /// This is a legitimate overload: the existing declarations are
  /// functions or function templates with different signatures.
  Ovl_Overload,

  /// This is not an overload because the signature exactly matches
  /// an existing declaration.
  Ovl_Match,

  /// This is not an overload because the lookup results contain a
  /// non-function.
  Ovl_NonFunction
};
OverloadKind CheckOverload(Scope *S,
                           FunctionDecl *New,
                           const LookupResult &OldDecls,
                           NamedDecl *&OldDecl,
                           bool IsForUsingDecl);
bool IsOverload(FunctionDecl *New, FunctionDecl *Old, bool IsForUsingDecl,
                bool ConsiderCudaAttrs = true,
                bool ConsiderRequiresClauses = true);

enum class AllowedExplicit {
  /// Allow no explicit functions to be used.
  None,
  /// Allow explicit conversion functions but not explicit constructors.
  Conversions,
  /// Allow both explicit conversion functions and explicit constructors.
  All
};

ImplicitConversionSequence
TryImplicitConversion(Expr *From, QualType ToType,
                      bool SuppressUserConversions,
                      AllowedExplicit AllowExplicit,
                      bool InOverloadResolution,
                      bool CStyle,
                      bool AllowObjCWritebackConversion);

bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
bool IsComplexPromotion(QualType FromType, QualType ToType);
bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                         bool InOverloadResolution,
                         QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCPointerConversion(QualType FromType, QualType ToType,
                             QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCWritebackConversion(QualType FromType, QualType ToType,
                               QualType &ConvertedType);
bool IsBlockPointerConversion(QualType FromType, QualType ToType,
                              QualType& ConvertedType);
bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
                                const FunctionProtoType *NewType,
                                unsigned *ArgPos = nullptr);
void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                QualType FromType, QualType ToType);

void maybeExtendBlockObject(ExprResult &E);
CastKind PrepareCastToObjCObjectPointer(ExprResult &E);
bool CheckPointerConversion(Expr *From, QualType ToType,
                            CastKind &Kind,
                            CXXCastPath& BasePath,
                            bool IgnoreBaseAccess,
                            bool Diagnose = true);
bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
                               bool InOverloadResolution,
                               QualType &ConvertedType);
bool CheckMemberPointerConversion(Expr *From, QualType ToType,
                                  CastKind &Kind,
                                  CXXCastPath &BasePath,
                                  bool IgnoreBaseAccess);
bool IsQualificationConversion(QualType FromType, QualType ToType,
                               bool CStyle, bool &ObjCLifetimeConversion);
bool IsFunctionConversion(QualType FromType, QualType ToType,
                          QualType &ResultTy);
bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
bool isSameOrCompatibleFunctionType(CanQualType Param, CanQualType Arg);

bool CanPerformAggregateInitializationForOverloadResolution(
    const InitializedEntity &Entity, InitListExpr *From);

bool IsStringInit(Expr *Init, const ArrayType *AT);

bool CanPerformCopyInitialization(const InitializedEntity &Entity,
                                  ExprResult Init);
ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
                                     SourceLocation EqualLoc,
                                     ExprResult Init,
                                     bool TopLevelOfInitList = false,
                                     bool AllowExplicit = false);
ExprResult PerformObjectArgumentInitialization(Expr *From,
                                               NestedNameSpecifier *Qualifier,
                                               NamedDecl *FoundDecl,
                                               CXXMethodDecl *Method);

/// Check that the lifetime of the initializer (and its subobjects) is
/// sufficient for initializing the entity, and perform lifetime extension
/// (when permitted) if not.
void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);

ExprResult PerformContextuallyConvertToBool(Expr *From);
ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);

/// Contexts in which a converted constant expression is required.
enum CCEKind {
  CCEK_CaseValue,   ///< Expression in a case label.
  CCEK_Enumerator,  ///< Enumerator value with fixed underlying type.
  CCEK_TemplateArg, ///< Value of a non-type template parameter.
  CCEK_ArrayBound,  ///< Array bound in array declarator or new-expression.
  CCEK_ExplicitBool ///< Condition in an explicit(bool) specifier.
};
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            llvm::APSInt &Value, CCEKind CCE);
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            APValue &Value, CCEKind CCE,
                                            NamedDecl *Dest = nullptr);

/// Abstract base class used to perform a contextual implicit
/// conversion from an expression to any type passing a filter.
class ContextualImplicitConverter {
public:
  bool Suppress;
  bool SuppressConversion;

  ContextualImplicitConverter(bool Suppress = false,
                              bool SuppressConversion = false)
      : Suppress(Suppress), SuppressConversion(SuppressConversion) {}

  /// Determine whether the specified type is a valid destination type
  /// for this conversion.
  virtual bool match(QualType T) = 0;

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the expression has incomplete class type.
  virtual SemaDiagnosticBuilder
  diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the only matching conversion function
  /// is explicit.
  virtual SemaDiagnosticBuilder diagnoseExplicitConv(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  /// Emits a note for the explicit conversion function.
  virtual SemaDiagnosticBuilder
  noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when there are multiple possible conversion
  /// functions.
  virtual SemaDiagnosticBuilder
  diagnoseAmbiguous(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a note for one of the candidate conversions.
  virtual SemaDiagnosticBuilder
  noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when we picked a conversion function
  /// (for cases when we are not allowed to pick a conversion function).
  virtual SemaDiagnosticBuilder diagnoseConversion(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  virtual ~ContextualImplicitConverter() {}
};

class ICEConvertDiagnoser : public ContextualImplicitConverter {
  bool AllowScopedEnumerations;

public:
  ICEConvertDiagnoser(bool AllowScopedEnumerations,
                      bool Suppress, bool SuppressConversion)
      : ContextualImplicitConverter(Suppress, SuppressConversion),
        AllowScopedEnumerations(AllowScopedEnumerations) {}

  /// Match an integral or (possibly scoped) enumeration type.
  bool match(QualType T) override;

  SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) override {
    return diagnoseNotInt(S, Loc, T);
  }

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNotInt(Sema &S, SourceLocation Loc, QualType T) = 0;
};

/// Perform a contextual implicit conversion.
ExprResult PerformContextualImplicitConversion(
    SourceLocation Loc, Expr *FromE, ContextualImplicitConverter &Converter);


enum ObjCSubscriptKind {
  OS_Array,
  OS_Dictionary,
  OS_Error
};
ObjCSubscriptKind CheckSubscriptingKind(Expr *FromE);

// Note that LK_String is intentionally after the other literals, as
// this is used for diagnostics logic.
enum ObjCLiteralKind {
  LK_Array,
  LK_Dictionary,
  LK_Numeric,
  LK_Boxed,
  LK_String,
  LK_Block,
  LK_None
};
ObjCLiteralKind CheckLiteralKind(Expr *FromE);

ExprResult PerformObjectMemberConversion(Expr *From,
                                         NestedNameSpecifier *Qualifier,
                                         NamedDecl *FoundDecl,
                                         NamedDecl *Member);

// Members have to be NamespaceDecl* or TranslationUnitDecl*.
// TODO: make this is a typesafe union.
typedef llvm::SmallSetVector<DeclContext   *, 16> AssociatedNamespaceSet;
typedef llvm::SmallSetVector<CXXRecordDecl *, 16> AssociatedClassSet;

using ADLCallKind = CallExpr::ADLCallKind;

void AddOverloadCandidate(FunctionDecl *Function, DeclAccessPair FoundDecl,
                          ArrayRef<Expr *> Args,
                          OverloadCandidateSet &CandidateSet,
                          bool SuppressUserConversions = false,
                          bool PartialOverloading = false,
                          bool AllowExplicit = true,
                          bool AllowExplicitConversion = false,
                          ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
                          ConversionSequenceList EarlyConversions = None,
                          OverloadCandidateParamOrder PO = {});
void AddFunctionCandidates(const UnresolvedSetImpl &Functions,
                    ArrayRef<Expr *> Args,
                    OverloadCandidateSet &CandidateSet,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    bool SuppressUserConversions = false,
                    bool PartialOverloading = false,
                    bool FirstArgumentIsBase = false);
void AddMethodCandidate(DeclAccessPair FoundDecl,
                        QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversion = false,
                        OverloadCandidateParamOrder PO = {});
void AddMethodCandidate(CXXMethodDecl *Method,
                        DeclAccessPair FoundDecl,
                        CXXRecordDecl *ActingContext, QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversions = false,
                        bool PartialOverloading = false,
                        ConversionSequenceList EarlyConversions = None,
                        OverloadCandidateParamOrder PO = {});
void AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                DeclAccessPair FoundDecl,
                                CXXRecordDecl *ActingContext,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                                QualType ObjectType,
                                Expr::Classification ObjectClassification,
                                ArrayRef<Expr *> Args,
                                OverloadCandidateSet& CandidateSet,
                                bool SuppressUserConversions = false,
                                bool PartialOverloading = false,
                                OverloadCandidateParamOrder PO = {});
void AddTemplateOverloadCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
    bool PartialOverloading = false, bool AllowExplicit = true,
    ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
    OverloadCandidateParamOrder PO = {});
bool CheckNonDependentConversions(
    FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
    ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
    ConversionSequenceList &Conversions, bool SuppressUserConversions,
    CXXRecordDecl *ActingContext = nullptr, QualType ObjectType = QualType(),
    Expr::Classification ObjectClassification = {},
    OverloadCandidateParamOrder PO = {});
void AddConversionCandidate(
    CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddTemplateConversionCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddSurrogateCandidate(CXXConversionDecl *Conversion,
                           DeclAccessPair FoundDecl,
                           CXXRecordDecl *ActingContext,
                           const FunctionProtoType *Proto,
                           Expr *Object, ArrayRef<Expr *> Args,
                           OverloadCandidateSet& CandidateSet);
void AddNonMemberOperatorCandidates(
    const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
    OverloadCandidateSet &CandidateSet,
    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr);
void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
                                 SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                 OverloadCandidateSet &CandidateSet,
                                 OverloadCandidateParamOrder PO = {});
void AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
                         OverloadCandidateSet& CandidateSet,
                         bool IsAssignmentOperator = false,
                         unsigned NumContextualBoolArguments = 0);
void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
                                  SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                  OverloadCandidateSet& CandidateSet);
void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                          SourceLocation Loc,
                                          ArrayRef<Expr *> Args,
                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                                          OverloadCandidateSet& CandidateSet,
                                          bool PartialOverloading = false);

// Emit as a 'note' the specific overload candidate
void NoteOverloadCandidate(
    NamedDecl *Found, FunctionDecl *Fn,
    OverloadCandidateRewriteKind RewriteKind = OverloadCandidateRewriteKind(),
    QualType DestType = QualType(), bool TakingAddress = false);

// Emit as a series of 'note's all template and non-templates identified by
// the expression Expr
void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType(),
                               bool TakingAddress = false);

/// Check the enable_if expressions on the given function. Returns the first
/// failing attribute, or NULL if they were all successful.
EnableIfAttr *CheckEnableIf(FunctionDecl *Function, SourceLocation CallLoc,
                            ArrayRef<Expr *> Args,
                            bool MissingImplicitThis = false);

/// Find the failed Boolean condition within a given Boolean
/// constant expression, and describe it with a string.
std::pair<Expr *, std::string> findFailedBooleanCondition(Expr *Cond);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// non-ArgDependent DiagnoseIfAttrs.
///
/// Argument-dependent diagnose_if attributes should be checked each time a
/// function is used as a direct callee of a function call.
///
/// Returns true if any errors were emitted.
bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
                                         const Expr *ThisArg,
                                         ArrayRef<const Expr *> Args,
                                         SourceLocation Loc);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// ArgDependent DiagnoseIfAttrs.
///
/// Argument-independent diagnose_if attributes should be checked on every use
/// of a function.
///
/// Returns true if any errors were emitted.
bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
                                           SourceLocation Loc);

/// Returns whether the given function's address can be taken or not,
/// optionally emitting a diagnostic if the address can't be taken.
///
/// Returns false if taking the address of the function is illegal.
bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
                                       bool Complain = false,
                                       SourceLocation Loc = SourceLocation());

// [PossiblyAFunctionType]  -->   [Return]
// NonFunctionType --> NonFunctionType
// R (A) --> R(A)
// R (*)(A) --> R (A)
// R (&)(A) --> R (A)
// R (S::*)(A) --> R (A)
QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);

FunctionDecl *
ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                   QualType TargetType,
                                   bool Complain,
                                   DeclAccessPair &Found,
                                   bool *pHadMultipleCandidates = nullptr);

FunctionDecl *
resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &FoundResult);

bool resolveAndFixAddressOfSingleOverloadCandidate(
    ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);

FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
                                            bool Complain = false,
                                            DeclAccessPair *Found = nullptr);

bool ResolveAndFixSingleFunctionTemplateSpecialization(
                    ExprResult &SrcExpr,
                    bool DoFunctionPointerConverion = false,
                    bool Complain = false,
                    SourceRange OpRangeForComplaining = SourceRange(),
                    QualType DestTypeForComplaining = QualType(),
                    unsigned DiagIDForComplaining = 0);


Expr *FixOverloadedFunctionReference(Expr *E,
                                     DeclAccessPair FoundDecl,
                                     FunctionDecl *Fn);
ExprResult FixOverloadedFunctionReference(ExprResult,
                                          DeclAccessPair FoundDecl,
                                          FunctionDecl *Fn);

void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
                                 ArrayRef<Expr *> Args,
                                 OverloadCandidateSet &CandidateSet,
                                 bool PartialOverloading = false);
void AddOverloadedCallCandidates(
    LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
    ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet);

// An enum used to represent the different possible results of building a
// range-based for loop.
enum ForRangeStatus {
  FRS_Success,
  FRS_NoViableFunction,
  FRS_DiagnosticIssued
};

ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
                                         SourceLocation RangeLoc,
                                         const DeclarationNameInfo &NameInfo,
                                         LookupResult &MemberLookup,
                                         OverloadCandidateSet *CandidateSet,
                                         Expr *Range, ExprResult *CallExpr);

ExprResult BuildOverloadedCallExpr(Scope *S, Expr *Fn,
                                   UnresolvedLookupExpr *ULE,
                                   SourceLocation LParenLoc,
                                   MultiExprArg Args,
                                   SourceLocation RParenLoc,
                                   Expr *ExecConfig,
                                   bool AllowTypoCorrection=true,
                                   bool CalleesAddressIsTaken=false);

bool buildOverloadedCallSet(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE,
                            MultiExprArg Args, SourceLocation RParenLoc,
                            OverloadCandidateSet *CandidateSet,
                            ExprResult *Result);

ExprResult CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
                                      NestedNameSpecifierLoc NNSLoc,
                                      DeclarationNameInfo DNI,
                                      const UnresolvedSetImpl &Fns,
                                      bool PerformADL = true);

ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
                                   UnaryOperatorKind Opc,
                                   const UnresolvedSetImpl &Fns,
                                   Expr *input, bool RequiresADL = true);

void LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
                           OverloadedOperatorKind Op,
                           const UnresolvedSetImpl &Fns,
                           ArrayRef<Expr *> Args, bool RequiresADL = true);
ExprResult CreateOverloadedBinOp(SourceLocation OpLoc,
                                 BinaryOperatorKind Opc,
                                 const UnresolvedSetImpl &Fns,
                                 Expr *LHS, Expr *RHS,
                                 bool RequiresADL = true,
                                 bool AllowRewrittenCandidates = true,
                                 FunctionDecl *DefaultedFn = nullptr);
ExprResult BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,
                                              const UnresolvedSetImpl &Fns,
                                              Expr *LHS, Expr *RHS,
                                              FunctionDecl *DefaultedFn);

ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
                                              SourceLocation RLoc,
                                              Expr *Base,Expr *Idx);

ExprResult BuildCallToMemberFunction(Scope *S, Expr *MemExpr,
                                     SourceLocation LParenLoc,
                                     MultiExprArg Args,
                                     SourceLocation RParenLoc,
                                     bool AllowRecovery = false);
ExprResult
BuildCallToObjectOfClassType(Scope *S, Expr *Object, SourceLocation LParenLoc,
                             MultiExprArg Args,
                             SourceLocation RParenLoc);

ExprResult BuildOverloadedArrowExpr(Scope *S, Expr *Base,
                                    SourceLocation OpLoc,
                                    bool *NoArrowOperatorFound = nullptr);

/// CheckCallReturnType - Checks that a call expression's return type is
/// complete. Returns true on failure. The location passed in is the location
/// that best represents the call.
bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
                         CallExpr *CE, FunctionDecl *FD);

/// Helpers for dealing with blocks and functions.
bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
                              bool CheckParameterNames);
void CheckCXXDefaultArguments(FunctionDecl *FD);
void CheckExtraCXXDefaultArguments(Declarator &D);
Scope *getNonFieldDeclScope(Scope *S);

/// \name Name lookup
///
/// These routines provide name lookup that is used during semantic
/// analysis to resolve the various kinds of names (identifiers,
/// overloaded operator names, constructor names, etc.) into zero or
/// more declarations within a particular scope. The major entry
/// points are LookupName, which performs unqualified name lookup,
/// and LookupQualifiedName, which performs qualified name lookup.
///
/// All name lookup is performed based on some specific criteria,
/// which specify what names will be visible to name lookup and how
/// far name lookup should work. These criteria are important both
/// for capturing language semantics (certain lookups will ignore
/// certain names, for example) and for performance, since name
/// lookup is often a bottleneck in the compilation of C++. Name
/// lookup criteria is specified via the LookupCriteria enumeration.
///
/// The results of name lookup can vary based on the kind of name
/// lookup performed, the current language, and the translation
/// unit. In C, for example, name lookup will either return nothing
/// (no entity found) or a single declaration. In C++, name lookup
/// can additionally refer to a set of overloaded functions or
/// result in an ambiguity. All of the possible results of name
/// lookup are captured by the LookupResult class, which provides
/// the ability to distinguish among them.
//@{

/// Describes the kind of name lookup to perform.
enum LookupNameKind {
  /// Ordinary name lookup, which finds ordinary names (functions,
  /// variables, typedefs, etc.) in C and most kinds of names
  /// (functions, variables, members, types, etc.) in C++.
  LookupOrdinaryName = 0,
  /// Tag name lookup, which finds the names of enums, classes,
  /// structs, and unions.
  LookupTagName,
  /// Label name lookup.
  LookupLabel,
  /// Member name lookup, which finds the names of
  /// class/struct/union members.
  LookupMemberName,
  /// Look up of an operator name (e.g., operator+) for use with
  /// operator overloading. This lookup is similar to ordinary name
  /// lookup, but will ignore any declarations that are class members.
  LookupOperatorName,
  /// Look up a name following ~ in a destructor name. This is an ordinary
  /// lookup, but prefers tags to typedefs.
  LookupDestructorName,
  /// Look up of a name that precedes the '::' scope resolution
  /// operator in C++. This lookup completely ignores operator, object,
  /// function, and enumerator names (C++ [basic.lookup.qual]p1).
  LookupNestedNameSpecifierName,
  /// Look up a namespace name within a C++ using directive or
  /// namespace alias definition, ignoring non-namespace names (C++
  /// [basic.lookup.udir]p1).
  LookupNamespaceName,
  /// Look up all declarations in a scope with the given name,
  /// including resolved using declarations.  This is appropriate
  /// for checking redeclarations for a using declaration.
  LookupUsingDeclName,
  /// Look up an ordinary name that is going to be redeclared as a
  /// name with linkage. This lookup ignores any declarations that
  /// are outside of the current scope unless they have linkage. See
  /// C99 6.2.2p4-5 and C++ [basic.link]p6.
  LookupRedeclarationWithLinkage,
  /// Look up a friend of a local class. This lookup does not look
  /// outside the innermost non-class scope. See C++11 [class.friend]p11.
  LookupLocalFriendName,
  /// Look up the name of an Objective-C protocol.
  LookupObjCProtocolName,
  /// Look up implicit 'self' parameter of an objective-c method.
  LookupObjCImplicitSelfParam,
  /// Look up the name of an OpenMP user-defined reduction operation.
  LookupOMPReductionName,
  /// Look up the name of an OpenMP user-defined mapper.
  LookupOMPMapperName,
  /// Look up any declaration with any name.
  LookupAnyName
};

/// Specifies whether (or how) name lookup is being performed for a
/// redeclaration (vs. a reference).
enum RedeclarationKind {
  /// The lookup is a reference to this name that is not for the
  /// purpose of redeclaring the name.
  NotForRedeclaration = 0,
  /// The lookup results will be used for redeclaration of a name,
  /// if an entity by that name already exists and is visible.
  ForVisibleRedeclaration,
  /// The lookup results will be used for redeclaration of a name
  /// with external linkage; non-visible lookup results with external linkage
  /// may also be found.
  ForExternalRedeclaration
};

RedeclarationKind forRedeclarationInCurContext() {
  // A declaration with an owning module for linkage can never link against
  // anything that is not visible. We don't need to check linkage here; if
  // the context has internal linkage, redeclaration lookup won't find things
  // from other TUs, and we can't safely compute linkage yet in general.
  if (cast<Decl>(CurContext)
          ->getOwningModuleForLinkage(/*IgnoreLinkage*/true))
    return ForVisibleRedeclaration;
  return ForExternalRedeclaration;
}

/// The possible outcomes of name lookup for a literal operator.
enum LiteralOperatorLookupResult {
  /// The lookup resulted in an error.
  LOLR_Error,
  /// The lookup found no match but no diagnostic was issued.
  LOLR_ErrorNoDiagnostic,
  /// The lookup found a single 'cooked' literal operator, which
  /// expects a normal literal to be built and passed to it.
  LOLR_Cooked,
  /// The lookup found a single 'raw' literal operator, which expects
  /// a string literal containing the spelling of the literal token.
  LOLR_Raw,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the characters of the spelling of the literal token to be
  /// passed as a non-type template argument pack.
  LOLR_Template,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the character type and characters of the spelling of the
  /// string literal token to be passed as template arguments.
  LOLR_StringTemplatePack,
};

SpecialMemberOverloadResult LookupSpecialMember(CXXRecordDecl *D,
                                                CXXSpecialMember SM,
                                                bool ConstArg,
                                                bool VolatileArg,
                                                bool RValueThis,
                                                bool ConstThis,
                                                bool VolatileThis);

typedef std::function<void(const TypoCorrection &)> TypoDiagnosticGenerator;
typedef std::function<ExprResult(Sema &, TypoExpr *, TypoCorrection)>
    TypoRecoveryCallback;

4054private:
bool CppLookupName(LookupResult &R, Scope *S);

struct TypoExprState {
  std::unique_ptr<TypoCorrectionConsumer> Consumer;
  TypoDiagnosticGenerator DiagHandler;
  TypoRecoveryCallback RecoveryHandler;
  TypoExprState();
  TypoExprState(TypoExprState &&other) noexcept;
  TypoExprState &operator=(TypoExprState &&other) noexcept;
};

/// The set of unhandled TypoExprs and their associated state.
llvm::MapVector<TypoExpr *, TypoExprState> DelayedTypos;

/// Creates a new TypoExpr AST node.
TypoExpr *createDelayedTypo(std::unique_ptr<TypoCorrectionConsumer> TCC,
                            TypoDiagnosticGenerator TDG,
                            TypoRecoveryCallback TRC, SourceLocation TypoLoc);

// The set of known/encountered (unique, canonicalized) NamespaceDecls.
//
// The boolean value will be true to indicate that the namespace was loaded
// from an AST/PCH file, or false otherwise.
llvm::MapVector<NamespaceDecl*, bool> KnownNamespaces;

/// Whether we have already loaded known namespaces from an extenal
/// source.
bool LoadedExternalKnownNamespaces;

/// Helper for CorrectTypo and CorrectTypoDelayed used to create and
/// populate a new TypoCorrectionConsumer. Returns nullptr if typo correction
/// should be skipped entirely.
std::unique_ptr<TypoCorrectionConsumer>
makeTypoCorrectionConsumer(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind, Scope *S,
                           CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           DeclContext *MemberContext, bool EnteringContext,
                           const ObjCObjectPointerType *OPT,
                           bool ErrorRecovery);

4096public:
const TypoExprState &getTypoExprState(TypoExpr *TE) const;

/// Clears the state of the given TypoExpr.
void clearDelayedTypo(TypoExpr *TE);

/// Look up a name, looking for a single declaration.  Return
/// null if the results were absent, ambiguous, or overloaded.
///
/// It is preferable to use the elaborated form and explicitly handle
/// ambiguity and overloaded.
NamedDecl *LookupSingleName(Scope *S, DeclarationName Name,
                            SourceLocation Loc,
                            LookupNameKind NameKind,
                            RedeclarationKind Redecl
                              = NotForRedeclaration);
bool LookupBuiltin(LookupResult &R);
void LookupNecessaryTypesForBuiltin(Scope *S, unsigned ID);
bool LookupName(LookupResult &R, Scope *S,
                bool AllowBuiltinCreation = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         bool InUnqualifiedLookup = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         CXXScopeSpec &SS);
bool LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
                      bool AllowBuiltinCreation = false,
                      bool EnteringContext = false);
ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II, SourceLocation IdLoc,
                                 RedeclarationKind Redecl
                                   = NotForRedeclaration);
bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);

void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
                                  UnresolvedSetImpl &Functions);

LabelDecl *LookupOrCreateLabel(IdentifierInfo *II, SourceLocation IdentLoc,
                               SourceLocation GnuLabelLoc = SourceLocation());

DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
CXXConstructorDecl *LookupDefaultConstructor(CXXRecordDecl *Class);
CXXConstructorDecl *LookupCopyingConstructor(CXXRecordDecl *Class,
                                             unsigned Quals);
CXXMethodDecl *LookupCopyingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                       bool RValueThis, unsigned ThisQuals);
CXXConstructorDecl *LookupMovingConstructor(CXXRecordDecl *Class,
                                            unsigned Quals);
CXXMethodDecl *LookupMovingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                      bool RValueThis, unsigned ThisQuals);
CXXDestructorDecl *LookupDestructor(CXXRecordDecl *Class);

bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id,
                            bool IsUDSuffix);
LiteralOperatorLookupResult
LookupLiteralOperator(Scope *S, LookupResult &R, ArrayRef<QualType> ArgTys,
                      bool AllowRaw, bool AllowTemplate,
                      bool AllowStringTemplate, bool DiagnoseMissing,
                      StringLiteral *StringLit = nullptr);
bool isKnownName(StringRef name);

/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
enum class FunctionEmissionStatus {
  Emitted,
  CUDADiscarded,     // Discarded due to CUDA/HIP hostness
  OMPDiscarded,      // Discarded due to OpenMP hostness
  TemplateDiscarded, // Discarded due to uninstantiated templates
  Unknown,
};
FunctionEmissionStatus getEmissionStatus(FunctionDecl *Decl,
                                         bool Final = false);

// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);

void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
                             ArrayRef<Expr *> Args, ADLResult &Functions);

void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool LoadExternal = true);
void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool IncludeDependentBases = false,
                        bool LoadExternal = true);

enum CorrectTypoKind {
  CTK_NonError,     // CorrectTypo used in a non error recovery situation.
  CTK_ErrorRecovery // CorrectTypo used in normal error recovery.
};

TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind,
                           Scope *S, CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           CorrectTypoKind Mode,
                           DeclContext *MemberContext = nullptr,
                           bool EnteringContext = false,
                           const ObjCObjectPointerType *OPT = nullptr,
                           bool RecordFailure = true);

TypoExpr *CorrectTypoDelayed(const DeclarationNameInfo &Typo,
                             Sema::LookupNameKind LookupKind, Scope *S,
                             CXXScopeSpec *SS,
                             CorrectionCandidateCallback &CCC,
                             TypoDiagnosticGenerator TDG,
                             TypoRecoveryCallback TRC, CorrectTypoKind Mode,
                             DeclContext *MemberContext = nullptr,
                             bool EnteringContext = false,
                             const ObjCObjectPointerType *OPT = nullptr);

/// Process any TypoExprs in the given Expr and its children,
/// generating diagnostics as appropriate and returning a new Expr if there
/// were typos that were all successfully corrected and ExprError if one or
/// more typos could not be corrected.
///
/// \param E The Expr to check for TypoExprs.
///
/// \param InitDecl A VarDecl to avoid because the Expr being corrected is its
/// initializer.
///
/// \param RecoverUncorrectedTypos If true, when typo correction fails, it
/// will rebuild the given Expr with all TypoExprs degraded to RecoveryExprs.
///
/// \param Filter A function applied to a newly rebuilt Expr to determine if
/// it is an acceptable/usable result from a single combination of typo
/// corrections. As long as the filter returns ExprError, different
/// combinations of corrections will be tried until all are exhausted.
ExprResult CorrectDelayedTyposInExpr(
    Expr *E, VarDecl *InitDecl = nullptr,
    bool RecoverUncorrectedTypos = false,
    llvm::function_ref<ExprResult(Expr *)> Filter =
        [](Expr *E) -> ExprResult { return E; });

ExprResult CorrectDelayedTyposInExpr(
    ExprResult ER, VarDecl *InitDecl = nullptr,
    bool RecoverUncorrectedTypos = false,
    llvm::function_ref<ExprResult(Expr *)> Filter =
        [](Expr *E) -> ExprResult { return E; }) {
  return ER.isInvalid()
             ? ER
             : CorrectDelayedTyposInExpr(ER.get(), InitDecl,
                                         RecoverUncorrectedTypos, Filter);
}

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  bool ErrorRecovery = true);

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  const PartialDiagnostic &PrevNote,
                  bool ErrorRecovery = true);

void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);

void FindAssociatedClassesAndNamespaces(SourceLocation InstantiationLoc,
                                        ArrayRef<Expr *> Args,
                                 AssociatedNamespaceSet &AssociatedNamespaces,
                                 AssociatedClassSet &AssociatedClasses);

void FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                          bool ConsiderLinkage, bool AllowInlineNamespace);

bool CheckRedeclarationModuleOwnership(NamedDecl *New, NamedDecl *Old);

void DiagnoseAmbiguousLookup(LookupResult &Result);
//@}

/// Attempts to produce a RecoveryExpr after some AST node cannot be created.
ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
                              ArrayRef<Expr *> SubExprs,
                              QualType T = QualType());

ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
                                        SourceLocation IdLoc,
                                        bool TypoCorrection = false);
FunctionDecl *CreateBuiltin(IdentifierInfo *II, QualType Type, unsigned ID,
                            SourceLocation Loc);
NamedDecl *LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
                               Scope *S, bool ForRedeclaration,
                               SourceLocation Loc);
NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
                                    Scope *S);
void AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
    FunctionDecl *FD);
void AddKnownFunctionAttributes(FunctionDecl *FD);

// More parsing and symbol table subroutines.

void ProcessPragmaWeak(Scope *S, Decl *D);
// Decl attributes - this routine is the top level dispatcher.
void ProcessDeclAttributes(Scope *S, Decl *D, const Declarator &PD);
// Helper for delayed processing of attributes.
void ProcessDeclAttributeDelayed(Decl *D,
                                 const ParsedAttributesView &AttrList);
void ProcessDeclAttributeList(Scope *S, Decl *D, const ParsedAttributesView &AL,
                           bool IncludeCXX11Attributes = true);
bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
                                 const ParsedAttributesView &AttrList);

void checkUnusedDeclAttributes(Declarator &D);

/// Handles semantic checking for features that are common to all attributes,
/// such as checking whether a parameter was properly specified, or the
/// correct number of arguments were passed, etc. Returns true if the
/// attribute has been diagnosed.
bool checkCommonAttributeFeatures(const Decl *D, const ParsedAttr &A);
bool checkCommonAttributeFeatures(const Stmt *S, const ParsedAttr &A);

/// Determine if type T is a valid subject for a nonnull and similar
/// attributes. By default, we look through references (the behavior used by
/// nonnull), but if the second parameter is true, then we treat a reference
/// type as valid.
bool isValidPointerAttrType(QualType T, bool RefOkay = false);

bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
bool CheckCallingConvAttr(const ParsedAttr &attr, CallingConv &CC,
                          const FunctionDecl *FD = nullptr);
bool CheckAttrTarget(const ParsedAttr &CurrAttr);
bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
                                    StringRef &Str,
                                    SourceLocation *ArgLocation = nullptr);
llvm::Error isValidSectionSpecifier(StringRef Str);
bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
bool checkMSInheritanceAttrOnDefinition(
    CXXRecordDecl *RD, SourceRange Range, bool BestCase,
    MSInheritanceModel SemanticSpelling);

void CheckAlignasUnderalignment(Decl *D);

/// Adjust the calling convention of a method to be the ABI default if it
/// wasn't specified explicitly.  This handles method types formed from
/// function type typedefs and typename template arguments.
void adjustMemberFunctionCC(QualType &T, bool IsStatic, bool IsCtorOrDtor,
                            SourceLocation Loc);

// Check if there is an explicit attribute, but only look through parens.
// The intent is to look for an attribute on the current declarator, but not
// one that came from a typedef.
bool hasExplicitCallingConv(QualType T);

/// Get the outermost AttributedType node that sets a calling convention.
/// Valid types should not have multiple attributes with different CCs.
const AttributedType *getCallingConvAttributedType(QualType T) const;

/// Process the attributes before creating an attributed statement. Returns
/// the semantic attributes that have been processed.
void ProcessStmtAttributes(Stmt *Stmt,
                           const ParsedAttributesWithRange &InAttrs,
                           SmallVectorImpl<const Attr *> &OutAttrs);

void WarnConflictingTypedMethods(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *MethodDecl,
                                 bool IsProtocolMethodDecl);

void CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *Overridden,
                                 bool IsProtocolMethodDecl);

/// WarnExactTypedMethods - This routine issues a warning if method
/// implementation declaration matches exactly that of its declaration.
void WarnExactTypedMethods(ObjCMethodDecl *Method,
                           ObjCMethodDecl *MethodDecl,
                           bool IsProtocolMethodDecl);

typedef llvm::SmallPtrSet<Selector, 8> SelectorSet;

/// CheckImplementationIvars - This routine checks if the instance variables
/// listed in the implelementation match those listed in the interface.
void CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
                              ObjCIvarDecl **Fields, unsigned nIvars,
                              SourceLocation Loc);

/// ImplMethodsVsClassMethods - This is main routine to warn if any method
/// remains unimplemented in the class or category \@implementation.
void ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
                               ObjCContainerDecl* IDecl,
                               bool IncompleteImpl = false);

/// DiagnoseUnimplementedProperties - This routine warns on those properties
/// which must be implemented by this implementation.
void DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                     ObjCContainerDecl *CDecl,
                                     bool SynthesizeProperties);

/// Diagnose any null-resettable synthesized setters.
void diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl);

/// DefaultSynthesizeProperties - This routine default synthesizes all
/// properties which must be synthesized in the class's \@implementation.
void DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
                                 ObjCInterfaceDecl *IDecl,
                                 SourceLocation AtEnd);
void DefaultSynthesizeProperties(Scope *S, Decl *D, SourceLocation AtEnd);

/// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
/// an ivar synthesized for 'Method' and 'Method' is a property accessor
/// declared in class 'IFace'.
bool IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
                                    ObjCMethodDecl *Method, ObjCIvarDecl *IV);

/// DiagnoseUnusedBackingIvarInAccessor - Issue an 'unused' warning if ivar which
/// backs the property is not used in the property's accessor.
void DiagnoseUnusedBackingIvarInAccessor(Scope *S,
                                         const ObjCImplementationDecl *ImplD);

/// GetIvarBackingPropertyAccessor - If method is a property setter/getter and
/// it property has a backing ivar, returns this ivar; otherwise, returns NULL.
/// It also returns ivar's property on success.
ObjCIvarDecl *GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
                                             const ObjCPropertyDecl *&PDecl) const;

/// Called by ActOnProperty to handle \@property declarations in
/// class extensions.
ObjCPropertyDecl *HandlePropertyInClassExtension(Scope *S,
                    SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD,
                    Selector GetterSel,
                    SourceLocation GetterNameLoc,
                    Selector SetterSel,
                    SourceLocation SetterNameLoc,
                    const bool isReadWrite,
                    unsigned &Attributes,
                    const unsigned AttributesAsWritten,
                    QualType T,
                    TypeSourceInfo *TSI,
                    tok::ObjCKeywordKind MethodImplKind);

/// Called by ActOnProperty and HandlePropertyInClassExtension to
/// handle creating the ObjcPropertyDecl for a category or \@interface.
ObjCPropertyDecl *CreatePropertyDecl(Scope *S,
                                     ObjCContainerDecl *CDecl,
                                     SourceLocation AtLoc,
                                     SourceLocation LParenLoc,
                                     FieldDeclarator &FD,
                                     Selector GetterSel,
                                     SourceLocation GetterNameLoc,
                                     Selector SetterSel,
                                     SourceLocation SetterNameLoc,
                                     const bool isReadWrite,
                                     const unsigned Attributes,
                                     const unsigned AttributesAsWritten,
                                     QualType T,
                                     TypeSourceInfo *TSI,
                                     tok::ObjCKeywordKind MethodImplKind,
                                     DeclContext *lexicalDC = nullptr);

/// AtomicPropertySetterGetterRules - This routine enforces the rule (via
/// warning) when atomic property has one but not the other user-declared
/// setter or getter.
void AtomicPropertySetterGetterRules(ObjCImplDecl* IMPDecl,
                                     ObjCInterfaceDecl* IDecl);

void DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D);

void DiagnoseMissingDesignatedInitOverrides(
                                        const ObjCImplementationDecl *ImplD,
                                        const ObjCInterfaceDecl *IFD);

void DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID, ObjCInterfaceDecl *SID);

enum MethodMatchStrategy {
  MMS_loose,
  MMS_strict
};

/// MatchTwoMethodDeclarations - Checks if two methods' type match and returns
/// true, or false, accordingly.
bool MatchTwoMethodDeclarations(const ObjCMethodDecl *Method,
                                const ObjCMethodDecl *PrevMethod,
                                MethodMatchStrategy strategy = MMS_strict);

/// MatchAllMethodDeclarations - Check methods declaraed in interface or
/// or protocol against those declared in their implementations.
void MatchAllMethodDeclarations(const SelectorSet &InsMap,
                                const SelectorSet &ClsMap,
                                SelectorSet &InsMapSeen,
                                SelectorSet &ClsMapSeen,
                                ObjCImplDecl* IMPDecl,
                                ObjCContainerDecl* IDecl,
                                bool &IncompleteImpl,
                                bool ImmediateClass,
                                bool WarnCategoryMethodImpl=false);

/// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
/// category matches with those implemented in its primary class and
/// warns each time an exact match is found.
void CheckCategoryVsClassMethodMatches(ObjCCategoryImplDecl *CatIMP);

/// Add the given method to the list of globally-known methods.
void addMethodToGlobalList(ObjCMethodList *List, ObjCMethodDecl *Method);

/// Returns default addr space for method qualifiers.
LangAS getDefaultCXXMethodAddrSpace() const;

4495private:
/// AddMethodToGlobalPool - Add an instance or factory method to the global
/// pool. See descriptoin of AddInstanceMethodToGlobalPool.
void AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl, bool instance);

/// LookupMethodInGlobalPool - Returns the instance or factory method and
/// optionally warns if there are multiple signatures.
ObjCMethodDecl *LookupMethodInGlobalPool(Selector Sel, SourceRange R,
                                         bool receiverIdOrClass,
                                         bool instance);

4506public:
/// - Returns instance or factory methods in global method pool for
/// given selector. It checks the desired kind first, if none is found, and
/// parameter checkTheOther is set, it then checks the other kind. If no such
/// method or only one method is found, function returns false; otherwise, it
/// returns true.
bool
CollectMultipleMethodsInGlobalPool(Selector Sel,
                                   SmallVectorImpl<ObjCMethodDecl*>& Methods,
                                   bool InstanceFirst, bool CheckTheOther,
                                   const ObjCObjectType *TypeBound = nullptr);

bool
AreMultipleMethodsInGlobalPool(Selector Sel, ObjCMethodDecl *BestMethod,
                               SourceRange R, bool receiverIdOrClass,
                               SmallVectorImpl<ObjCMethodDecl*>& Methods);

void
DiagnoseMultipleMethodInGlobalPool(SmallVectorImpl<ObjCMethodDecl*> &Methods,
                                   Selector Sel, SourceRange R,
                                   bool receiverIdOrClass);

4528private:
/// - Returns a selector which best matches given argument list or
/// nullptr if none could be found
ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
                                 bool IsInstance,
                                 SmallVectorImpl<ObjCMethodDecl*>& Methods);


/// Record the typo correction failure and return an empty correction.
TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
                                bool RecordFailure = true) {
  if (RecordFailure)
    TypoCorrectionFailures[Typo].insert(TypoLoc);
  return TypoCorrection();
}

4544public:
/// AddInstanceMethodToGlobalPool - All instance methods in a translation
/// unit are added to a global pool. This allows us to efficiently associate
/// a selector with a method declaraation for purposes of typechecking
/// messages sent to "id" (where the class of the object is unknown).
void AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/true);
}

/// AddFactoryMethodToGlobalPool - Same as above, but for factory methods.
void AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/false);
}

/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
/// pool.
void AddAnyMethodToGlobalPool(Decl *D);

/// LookupInstanceMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupInstanceMethodInGlobalPool(Selector Sel, SourceRange R,
                                                 bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/true);
}

/// LookupFactoryMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupFactoryMethodInGlobalPool(Selector Sel, SourceRange R,
                                                bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/false);
}

const ObjCMethodDecl *SelectorsForTypoCorrection(Selector Sel,
                            QualType ObjectType=QualType());
/// LookupImplementedMethodInGlobalPool - Returns the method which has an
/// implementation.
ObjCMethodDecl *LookupImplementedMethodInGlobalPool(Selector Sel);

/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
/// initialization.
void CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
                                SmallVectorImpl<ObjCIvarDecl*> &Ivars);

//===--------------------------------------------------------------------===//
// Statement Parsing Callbacks: SemaStmt.cpp.
4591public:
class FullExprArg {
public:
  FullExprArg() : E(nullptr) { }
  FullExprArg(Sema &actions) : E(nullptr) { }

  ExprResult release() {
    return E;
  }

  Expr *get() const { return E; }

  Expr *operator->() {
    return E;
  }

private:
  // FIXME: No need to make the entire Sema class a friend when it's just
  // Sema::MakeFullExpr that needs access to the constructor below.
  friend class Sema;

  explicit FullExprArg(Expr *expr) : E(expr) {}

  Expr *E;
};

FullExprArg MakeFullExpr(Expr *Arg) {
  return MakeFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation());
}
FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
  return FullExprArg(
      ActOnFinishFullExpr(Arg, CC, /*DiscardedValue*/ false).get());
}
FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
  ExprResult FE =
      ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
                          /*DiscardedValue*/ true);
  return FullExprArg(FE.get());
}

StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
StmtResult ActOnExprStmtError();

StmtResult ActOnNullStmt(SourceLocation SemiLoc,
                         bool HasLeadingEmptyMacro = false);

void ActOnStartOfCompoundStmt(bool IsStmtExpr);
void ActOnAfterCompoundStatementLeadingPragmas();
void ActOnFinishOfCompoundStmt();
StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                             ArrayRef<Stmt *> Elts, bool isStmtExpr);

/// A RAII object to enter scope of a compound statement.
class CompoundScopeRAII {
public:
  CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
    S.ActOnStartOfCompoundStmt(IsStmtExpr);
  }

  ~CompoundScopeRAII() {
    S.ActOnFinishOfCompoundStmt();
  }

private:
  Sema &S;
};

/// An RAII helper that pops function a function scope on exit.
struct FunctionScopeRAII {
  Sema &S;
  bool Active;
  FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
  ~FunctionScopeRAII() {
    if (Active)
      S.PopFunctionScopeInfo();
  }
  void disable() { Active = false; }
};

StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl,
                                 SourceLocation StartLoc,
                                 SourceLocation EndLoc);
void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
StmtResult ActOnForEachLValueExpr(Expr *E);
ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
                         SourceLocation DotDotDotLoc, ExprResult RHS,
                         SourceLocation ColonLoc);
void ActOnCaseStmtBody(Stmt *CaseStmt, Stmt *SubStmt);

StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
                                    SourceLocation ColonLoc,
                                    Stmt *SubStmt, Scope *CurScope);
StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
                          SourceLocation ColonLoc, Stmt *SubStmt);

StmtResult BuildAttributedStmt(SourceLocation AttrsLoc,
                               ArrayRef<const Attr *> Attrs, Stmt *SubStmt);
StmtResult ActOnAttributedStmt(const ParsedAttributesWithRange &AttrList,
                               Stmt *SubStmt);

class ConditionResult;
StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       SourceLocation LParenLoc, Stmt *InitStmt,
                       ConditionResult Cond, SourceLocation RParenLoc,
                       Stmt *ThenVal, SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       SourceLocation LParenLoc, Stmt *InitStmt,
                       ConditionResult Cond, SourceLocation RParenLoc,
                       Stmt *ThenVal, SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
                                  SourceLocation LParenLoc, Stmt *InitStmt,
                                  ConditionResult Cond,
                                  SourceLocation RParenLoc);
StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                         Stmt *Switch, Stmt *Body);
StmtResult ActOnWhileStmt(SourceLocation WhileLoc, SourceLocation LParenLoc,
                          ConditionResult Cond, SourceLocation RParenLoc,
                          Stmt *Body);
StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
                       SourceLocation WhileLoc, SourceLocation CondLParen,
                       Expr *Cond, SourceLocation CondRParen);

StmtResult ActOnForStmt(SourceLocation ForLoc,
                        SourceLocation LParenLoc,
                        Stmt *First,
                        ConditionResult Second,
                        FullExprArg Third,
                        SourceLocation RParenLoc,
                        Stmt *Body);
ExprResult CheckObjCForCollectionOperand(SourceLocation forLoc,
                                         Expr *collection);
StmtResult ActOnObjCForCollectionStmt(SourceLocation ForColLoc,
                                      Stmt *First, Expr *collection,
                                      SourceLocation RParenLoc);
StmtResult FinishObjCForCollectionStmt(Stmt *ForCollection, Stmt *Body);

enum BuildForRangeKind {
  /// Initial building of a for-range statement.
  BFRK_Build,
  /// Instantiation or recovery rebuild of a for-range statement. Don't
  /// attempt any typo-correction.
  BFRK_Rebuild,
  /// Determining whether a for-range statement could be built. Avoid any
  /// unnecessary or irreversible actions.
  BFRK_Check
};

StmtResult ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                Stmt *LoopVar,
                                SourceLocation ColonLoc, Expr *Collection,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult BuildCXXForRangeStmt(SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                SourceLocation ColonLoc,
                                Stmt *RangeDecl, Stmt *Begin, Stmt *End,
                                Expr *Cond, Expr *Inc,
                                Stmt *LoopVarDecl,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult FinishCXXForRangeStmt(Stmt *ForRange, Stmt *Body);

StmtResult ActOnGotoStmt(SourceLocation GotoLoc,
                         SourceLocation LabelLoc,
                         LabelDecl *TheDecl);
StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
                                 SourceLocation StarLoc,
                                 Expr *DestExp);
StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope);
StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope);

void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind, unsigned NumParams);
typedef std::pair<StringRef, QualType> CapturedParamNameType;
void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind,
                              ArrayRef<CapturedParamNameType> Params,
                              unsigned OpenMPCaptureLevel = 0);
StmtResult ActOnCapturedRegionEnd(Stmt *S);
void ActOnCapturedRegionError();
RecordDecl *CreateCapturedStmtRecordDecl(CapturedDecl *&CD,
                                         SourceLocation Loc,
                                         unsigned NumParams);

struct NamedReturnInfo {
  const VarDecl *Candidate;

  enum Status : uint8_t { None, MoveEligible, MoveEligibleAndCopyElidable };
  Status S;

  bool isMoveEligible() const { return S != None; };
  bool isCopyElidable() const { return S == MoveEligibleAndCopyElidable; }
};
enum class SimplerImplicitMoveMode { ForceOff, Normal, ForceOn };
NamedReturnInfo getNamedReturnInfo(
    Expr *&E, SimplerImplicitMoveMode Mode = SimplerImplicitMoveMode::Normal);
NamedReturnInfo getNamedReturnInfo(const VarDecl *VD);
const VarDecl *getCopyElisionCandidate(NamedReturnInfo &Info,
                                       QualType ReturnType);

ExprResult
PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
                                const NamedReturnInfo &NRInfo, Expr *Value,
                                bool SupressSimplerImplicitMoves = false);

StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                           Scope *CurScope);
StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);
StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                                   NamedReturnInfo &NRInfo,
                                   bool SupressSimplerImplicitMoves);

StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                           bool IsVolatile, unsigned NumOutputs,
                           unsigned NumInputs, IdentifierInfo **Names,
                           MultiExprArg Constraints, MultiExprArg Exprs,
                           Expr *AsmString, MultiExprArg Clobbers,
                           unsigned NumLabels,
                           SourceLocation RParenLoc);

void FillInlineAsmIdentifierInfo(Expr *Res,
                                 llvm::InlineAsmIdentifierInfo &Info);
ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                                     UnqualifiedId &Id,
                                     bool IsUnevaluatedContext);
bool LookupInlineAsmField(StringRef Base, StringRef Member,
                          unsigned &Offset, SourceLocation AsmLoc);
ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
                                       SourceLocation AsmLoc);
StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                          ArrayRef<Token> AsmToks,
                          StringRef AsmString,
                          unsigned NumOutputs, unsigned NumInputs,
                          ArrayRef<StringRef> Constraints,
                          ArrayRef<StringRef> Clobbers,
                          ArrayRef<Expr*> Exprs,
                          SourceLocation EndLoc);
LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
                                 SourceLocation Location,
                                 bool AlwaysCreate);

VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                SourceLocation StartLoc,
                                SourceLocation IdLoc, IdentifierInfo *Id,
                                bool Invalid = false);

Decl *ActOnObjCExceptionDecl(Scope *S, Declarator &D);

StmtResult ActOnObjCAtCatchStmt(SourceLocation AtLoc, SourceLocation RParen,
                                Decl *Parm, Stmt *Body);

StmtResult ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body);

StmtResult ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
                              MultiStmtArg Catch, Stmt *Finally);

StmtResult BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw);
StmtResult ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
                                Scope *CurScope);
ExprResult ActOnObjCAtSynchronizedOperand(SourceLocation atLoc,
                                          Expr *operand);
StmtResult ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc,
                                       Expr *SynchExpr,
                                       Stmt *SynchBody);

StmtResult ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body);

VarDecl *BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                   SourceLocation StartLoc,
                                   SourceLocation IdLoc,
                                   IdentifierInfo *Id);

Decl *ActOnExceptionDeclarator(Scope *S, Declarator &D);

StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc,
                              Decl *ExDecl, Stmt *HandlerBlock);
StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
                            ArrayRef<Stmt *> Handlers);

StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
                            SourceLocation TryLoc, Stmt *TryBlock,
                            Stmt *Handler);
StmtResult ActOnSEHExceptBlock(SourceLocation Loc,
                               Expr *FilterExpr,
                               Stmt *Block);
void ActOnStartSEHFinallyBlock();
void ActOnAbortSEHFinallyBlock();
StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);

void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);

bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const;

/// If it's a file scoped decl that must warn if not used, keep track
/// of it.
void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);

/// DiagnoseUnusedExprResult - If the statement passed in is an expression
/// whose result is unused, warn.
void DiagnoseUnusedExprResult(const Stmt *S);
void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
void DiagnoseUnusedDecl(const NamedDecl *ND);

/// If VD is set but not otherwise used, diagnose, for a parameter or a
/// variable.
void DiagnoseUnusedButSetDecl(const VarDecl *VD);

/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
/// statement as a \p Body, and it is located on the same line.
///
/// This helps prevent bugs due to typos, such as:
///     if (condition);
///       do_stuff();
void DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
                           const Stmt *Body,
                           unsigned DiagID);

/// Warn if a for/while loop statement \p S, which is followed by
/// \p PossibleBody, has a suspicious null statement as a body.
void DiagnoseEmptyLoopBody(const Stmt *S,
                           const Stmt *PossibleBody);

/// Warn if a value is moved to itself.
void DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
                      SourceLocation OpLoc);

/// Warn if we're implicitly casting from a _Nullable pointer type to a
/// _Nonnull one.
void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
                                         SourceLocation Loc);

/// Warn when implicitly casting 0 to nullptr.
void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);

ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
  return DelayedDiagnostics.push(pool);
}
void PopParsingDeclaration(ParsingDeclState state, Decl *decl);

typedef ProcessingContextState ParsingClassState;
ParsingClassState PushParsingClass() {
  ParsingClassDepth++;
  return DelayedDiagnostics.pushUndelayed();
}
void PopParsingClass(ParsingClassState state) {
  ParsingClassDepth--;
  DelayedDiagnostics.popUndelayed(state);
}

void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);

void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                                const ObjCInterfaceDecl *UnknownObjCClass,
                                bool ObjCPropertyAccess,
                                bool AvoidPartialAvailabilityChecks = false,
                                ObjCInterfaceDecl *ClassReceiver = nullptr);

bool makeUnavailableInSystemHeader(SourceLocation loc,
                                   UnavailableAttr::ImplicitReason reason);

/// Issue any -Wunguarded-availability warnings in \c FD
void DiagnoseUnguardedAvailabilityViolations(Decl *FD);

void handleDelayedAvailabilityCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

//===--------------------------------------------------------------------===//
// Expression Parsing Callbacks: SemaExpr.cpp.

bool CanUseDecl(NamedDecl *D, bool TreatUnavailableAsInvalid);
bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                       const ObjCInterfaceDecl *UnknownObjCClass = nullptr,
                       bool ObjCPropertyAccess = false,
                       bool AvoidPartialAvailabilityChecks = false,
                       ObjCInterfaceDecl *ClassReciever = nullptr);
void NoteDeletedFunction(FunctionDecl *FD);
void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
bool DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *PD,
                                      ObjCMethodDecl *Getter,
                                      SourceLocation Loc);
void DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
                           ArrayRef<Expr *> Args);

void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, Decl *LambdaContextDecl = nullptr,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
void PopExpressionEvaluationContext();

void DiscardCleanupsInEvaluationContext();

ExprResult TransformToPotentiallyEvaluated(Expr *E);
ExprResult HandleExprEvaluationContextForTypeof(Expr *E);

ExprResult CheckUnevaluatedOperand(Expr *E);
void CheckUnusedVolatileAssignment(Expr *E);

ExprResult ActOnConstantExpression(ExprResult Res);

// Functions for marking a declaration referenced.  These functions also
// contain the relevant logic for marking if a reference to a function or
// variable is an odr-use (in the C++11 sense).  There are separate variants
// for expressions referring to a decl; these exist because odr-use marking
// needs to be delayed for some constant variables when we build one of the
// named expressions.
//
// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
// should usually be true. This only needs to be set to false if the lack of
// odr-use cannot be determined from the current context (for instance,
// because the name denotes a virtual function and was written without an
// explicit nested-name-specifier).
void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool MightBeOdrUse);
void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
                            bool MightBeOdrUse = true);
void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
void MarkDeclRefReferenced(DeclRefExpr *E, const Expr *Base = nullptr);
void MarkMemberReferenced(MemberExpr *E);
void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
void MarkCaptureUsedInEnclosingContext(VarDecl *Capture, SourceLocation Loc,
                                       unsigned CapturingScopeIndex);

ExprResult CheckLValueToRValueConversionOperand(Expr *E);
void CleanupVarDeclMarking();

enum TryCaptureKind {
  TryCapture_Implicit, TryCapture_ExplicitByVal, TryCapture_ExplicitByRef
};

/// Try to capture the given variable.
///
/// \param Var The variable to capture.
///
/// \param Loc The location at which the capture occurs.
///
/// \param Kind The kind of capture, which may be implicit (for either a
/// block or a lambda), or explicit by-value or by-reference (for a lambda).
///
/// \param EllipsisLoc The location of the ellipsis, if one is provided in
/// an explicit lambda capture.
///
/// \param BuildAndDiagnose Whether we are actually supposed to add the
/// captures or diagnose errors. If false, this routine merely check whether
/// the capture can occur without performing the capture itself or complaining
/// if the variable cannot be captured.
///
/// \param CaptureType Will be set to the type of the field used to capture
/// this variable in the innermost block or lambda. Only valid when the
/// variable can be captured.
///
/// \param DeclRefType Will be set to the type of a reference to the capture
/// from within the current scope. Only valid when the variable can be
/// captured.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// variables that may or may not be used in certain specializations of
/// a nested generic lambda.
///
/// \returns true if an error occurred (i.e., the variable cannot be
/// captured) and false if the capture succeeded.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc, TryCaptureKind Kind,
                        SourceLocation EllipsisLoc, bool BuildAndDiagnose,
                        QualType &CaptureType,
                        QualType &DeclRefType,
                        const unsigned *const FunctionScopeIndexToStopAt);

/// Try to capture the given variable.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc,
                        TryCaptureKind Kind = TryCapture_Implicit,
                        SourceLocation EllipsisLoc = SourceLocation());

/// Checks if the variable must be captured.
bool NeedToCaptureVariable(VarDecl *Var, SourceLocation Loc);

/// Given a variable, determine the type that a reference to that
/// variable will have in the given scope.
QualType getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc);

/// Mark all of the declarations referenced within a particular AST node as
/// referenced. Used when template instantiation instantiates a non-dependent
/// type -- entities referenced by the type are now referenced.
void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
void MarkDeclarationsReferencedInExpr(Expr *E,
                                      bool SkipLocalVariables = false);

/// Try to recover by turning the given expression into a
/// call.  Returns true if recovery was attempted or an error was
/// emitted; this may also leave the ExprResult invalid.
bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
                          bool ForceComplain = false,
                          bool (*IsPlausibleResult)(QualType) = nullptr);

/// Figure out if an expression could be turned into a call.
bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
                   UnresolvedSetImpl &NonTemplateOverloads);

/// Try to convert an expression \p E to type \p Ty. Returns the result of the
/// conversion.
ExprResult tryConvertExprToType(Expr *E, QualType Ty);

/// Conditionally issue a diagnostic based on the current
/// evaluation context.
///
/// \param Statement If Statement is non-null, delay reporting the
/// diagnostic until the function body is parsed, and then do a basic
/// reachability analysis to determine if the statement is reachable.
/// If it is unreachable, the diagnostic will not be emitted.
bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
                         const PartialDiagnostic &PD);
/// Similar, but diagnostic is only produced if all the specified statements
/// are reachable.
bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt*> Stmts,
                         const PartialDiagnostic &PD);

// Primary Expressions.
SourceRange getExprRange(Expr *E) const;

ExprResult ActOnIdExpression(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    UnqualifiedId &Id, bool HasTrailingLParen, bool IsAddressOfOperand,
    CorrectionCandidateCallback *CCC = nullptr,
    bool IsInlineAsmIdentifier = false, Token *KeywordReplacement = nullptr);

void DecomposeUnqualifiedId(const UnqualifiedId &Id,
                            TemplateArgumentListInfo &Buffer,
                            DeclarationNameInfo &NameInfo,
                            const TemplateArgumentListInfo *&TemplateArgs);

bool DiagnoseDependentMemberLookup(LookupResult &R);

bool
DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
                    CorrectionCandidateCallback &CCC,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    ArrayRef<Expr *> Args = None, TypoExpr **Out = nullptr);

DeclResult LookupIvarInObjCMethod(LookupResult &Lookup, Scope *S,
                                  IdentifierInfo *II);
ExprResult BuildIvarRefExpr(Scope *S, SourceLocation Loc, ObjCIvarDecl *IV);

ExprResult LookupInObjCMethod(LookupResult &LookUp, Scope *S,
                              IdentifierInfo *II,
                              bool AllowBuiltinCreation=false);

ExprResult ActOnDependentIdExpression(const CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      const DeclarationNameInfo &NameInfo,
                                      bool isAddressOfOperand,
                              const TemplateArgumentListInfo *TemplateArgs);

/// If \p D cannot be odr-used in the current expression evaluation context,
/// return a reason explaining why. Otherwise, return NOUR_None.
NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);

DeclRefExpr *BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                              SourceLocation Loc,
                              const CXXScopeSpec *SS = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 const CXXScopeSpec *SS = nullptr,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 NestedNameSpecifierLoc NNS,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);

ExprResult
BuildAnonymousStructUnionMemberReference(
    const CXXScopeSpec &SS,
    SourceLocation nameLoc,
    IndirectFieldDecl *indirectField,
    DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_none),
    Expr *baseObjectExpr = nullptr,
    SourceLocation opLoc = SourceLocation());

ExprResult BuildPossibleImplicitMemberExpr(
    const CXXScopeSpec &SS, SourceLocation TemplateKWLoc, LookupResult &R,
    const TemplateArgumentListInfo *TemplateArgs, const Scope *S,
    UnresolvedLookupExpr *AsULE = nullptr);
ExprResult BuildImplicitMemberExpr(const CXXScopeSpec &SS,
                                   SourceLocation TemplateKWLoc,
                                   LookupResult &R,
                              const TemplateArgumentListInfo *TemplateArgs,
                                   bool IsDefiniteInstance,
                                   const Scope *S);
bool UseArgumentDependentLookup(const CXXScopeSpec &SS,
                                const LookupResult &R,
                                bool HasTrailingLParen);

ExprResult
BuildQualifiedDeclarationNameExpr(CXXScopeSpec &SS,
                                  const DeclarationNameInfo &NameInfo,
                                  bool IsAddressOfOperand, const Scope *S,
                                  TypeSourceInfo **RecoveryTSI = nullptr);

ExprResult BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                              const DeclarationNameInfo &NameInfo,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS,
                                    LookupResult &R,
                                    bool NeedsADL,
                                    bool AcceptInvalidDecl = false);
ExprResult BuildDeclarationNameExpr(
    const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
    NamedDecl *FoundD = nullptr,
    const TemplateArgumentListInfo *TemplateArgs = nullptr,
    bool AcceptInvalidDecl = false);

ExprResult BuildLiteralOperatorCall(LookupResult &R,
                    DeclarationNameInfo &SuffixInfo,
                    ArrayRef<Expr *> Args,
                    SourceLocation LitEndLoc,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr);

ExprResult BuildPredefinedExpr(SourceLocation Loc,
                               PredefinedExpr::IdentKind IK);
ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
ExprResult ActOnIntegerConstant(SourceLocation Loc, uint64_t Val);

ExprResult BuildSYCLUniqueStableNameExpr(SourceLocation OpLoc,
                                         SourceLocation LParen,
                                         SourceLocation RParen,
                                         TypeSourceInfo *TSI);
ExprResult ActOnSYCLUniqueStableNameExpr(SourceLocation OpLoc,
                                         SourceLocation LParen,
                                         SourceLocation RParen,
                                         ParsedType ParsedTy);

bool CheckLoopHintExpr(Expr *E, SourceLocation Loc);

ExprResult ActOnNumericConstant(const Token &Tok, Scope *UDLScope = nullptr);
ExprResult ActOnCharacterConstant(const Token &Tok,
                                  Scope *UDLScope = nullptr);
ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
ExprResult ActOnParenListExpr(SourceLocation L,
                              SourceLocation R,
                              MultiExprArg Val);

/// ActOnStringLiteral - The specified tokens were lexed as pasted string
/// fragments (e.g. "foo" "bar" L"baz").
ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
                              Scope *UDLScope = nullptr);

ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
                                     SourceLocation DefaultLoc,
                                     SourceLocation RParenLoc,
                                     Expr *ControllingExpr,
                                     ArrayRef<ParsedType> ArgTypes,
                                     ArrayRef<Expr *> ArgExprs);
ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
                                      SourceLocation DefaultLoc,
                                      SourceLocation RParenLoc,
                                      Expr *ControllingExpr,
                                      ArrayRef<TypeSourceInfo *> Types,
                                      ArrayRef<Expr *> Exprs);

// Binary/Unary Operators.  'Tok' is the token for the operator.
ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
                                Expr *InputExpr);
ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc,
                        UnaryOperatorKind Opc, Expr *Input);
ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc,
                        tok::TokenKind Op, Expr *Input);

bool isQualifiedMemberAccess(Expr *E);
QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);

ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
                                          SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind,
                                          SourceRange R);
ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind);
ExprResult
  ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
                                UnaryExprOrTypeTrait ExprKind,
                                bool IsType, void *TyOrEx,
                                SourceRange ArgRange);

ExprResult CheckPlaceholderExpr(Expr *E);
bool CheckVecStepExpr(Expr *E);

bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
                                      SourceRange ExprRange,
                                      UnaryExprOrTypeTrait ExprKind);
ExprResult ActOnSizeofParameterPackExpr(Scope *S,
                                        SourceLocation OpLoc,
                                        IdentifierInfo &Name,
                                        SourceLocation NameLoc,
                                        SourceLocation RParenLoc);
ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                               tok::TokenKind Kind, Expr *Input);

ExprResult ActOnArraySubscriptExpr(Scope *S, Expr *Base, SourceLocation LLoc,
                                   Expr *Idx, SourceLocation RLoc);
ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
                                           Expr *Idx, SourceLocation RLoc);

ExprResult CreateBuiltinMatrixSubscriptExpr(Expr *Base, Expr *RowIdx,
                                            Expr *ColumnIdx,
                                            SourceLocation RBLoc);

ExprResult ActOnOMPArraySectionExpr(Expr *Base, SourceLocation LBLoc,
                                    Expr *LowerBound,
                                    SourceLocation ColonLocFirst,
                                    SourceLocation ColonLocSecond,
                                    Expr *Length, Expr *Stride,
                                    SourceLocation RBLoc);
ExprResult ActOnOMPArrayShapingExpr(Expr *Base, SourceLocation LParenLoc,
                                    SourceLocation RParenLoc,
                                    ArrayRef<Expr *> Dims,
                                    ArrayRef<SourceRange> Brackets);

/// Data structure for iterator expression.
struct OMPIteratorData {
  IdentifierInfo *DeclIdent = nullptr;
  SourceLocation DeclIdentLoc;
  ParsedType Type;
  OMPIteratorExpr::IteratorRange Range;
  SourceLocation AssignLoc;
  SourceLocation ColonLoc;
  SourceLocation SecColonLoc;
};

ExprResult ActOnOMPIteratorExpr(Scope *S, SourceLocation IteratorKwLoc,
                                SourceLocation LLoc, SourceLocation RLoc,
                                ArrayRef<OMPIteratorData> Data);

// This struct is for use by ActOnMemberAccess to allow
// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
// changing the access operator from a '.' to a '->' (to see if that is the
// change needed to fix an error about an unknown member, e.g. when the class
// defines a custom operator->).
struct ActOnMemberAccessExtraArgs {
  Scope *S;
  UnqualifiedId &Id;
  Decl *ObjCImpDecl;
};

ExprResult BuildMemberReferenceExpr(
    Expr *Base, QualType BaseType, SourceLocation OpLoc, bool IsArrow,
    CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
    const TemplateArgumentListInfo *TemplateArgs,
    const Scope *S,
    ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult
BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
                         bool IsArrow, const CXXScopeSpec &SS,
                         SourceLocation TemplateKWLoc,
                         NamedDecl *FirstQualifierInScope, LookupResult &R,
                         const TemplateArgumentListInfo *TemplateArgs,
                         const Scope *S,
                         bool SuppressQualifierCheck = false,
                         ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult BuildFieldReferenceExpr(Expr *BaseExpr, bool IsArrow,
                                   SourceLocation OpLoc,
                                   const CXXScopeSpec &SS, FieldDecl *Field,
                                   DeclAccessPair FoundDecl,
                                   const DeclarationNameInfo &MemberNameInfo);

ExprResult PerformMemberExprBaseConversion(Expr *Base, bool IsArrow);

bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
                                   const CXXScopeSpec &SS,
                                   const LookupResult &R);

ExprResult ActOnDependentMemberExpr(Expr *Base, QualType BaseType,
                                    bool IsArrow, SourceLocation OpLoc,
                                    const CXXScopeSpec &SS,
                                    SourceLocation TemplateKWLoc,
                                    NamedDecl *FirstQualifierInScope,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult ActOnMemberAccessExpr(Scope *S, Expr *Base,
                                 SourceLocation OpLoc,
                                 tok::TokenKind OpKind,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 UnqualifiedId &Member,
                                 Decl *ObjCImpDecl);

MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                const CXXScopeSpec *SS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);
MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);

void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
bool ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
                             FunctionDecl *FDecl,
                             const FunctionProtoType *Proto,
                             ArrayRef<Expr *> Args,
                             SourceLocation RParenLoc,
                             bool ExecConfig = false);
void CheckStaticArrayArgument(SourceLocation CallLoc,
                              ParmVarDecl *Param,
                              const Expr *ArgExpr);

/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
ExprResult ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr);
ExprResult BuildCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr,
                         bool IsExecConfig = false,
                         bool AllowRecovery = false);
Expr *BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
                           MultiExprArg CallArgs);
enum class AtomicArgumentOrder { API, AST };
ExprResult
BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
                SourceLocation RParenLoc, MultiExprArg Args,
                AtomicExpr::AtomicOp Op,
                AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
ExprResult
BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl, SourceLocation LParenLoc,
                      ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
                      Expr *Config = nullptr, bool IsExecConfig = false,
                      ADLCallKind UsesADL = ADLCallKind::NotADL);

ExprResult ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc,
                                   MultiExprArg ExecConfig,
                                   SourceLocation GGGLoc);

ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
                         Declarator &D, ParsedType &Ty,
                         SourceLocation RParenLoc, Expr *CastExpr);
ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc,
                               TypeSourceInfo *Ty,
                               SourceLocation RParenLoc,
                               Expr *Op);
CastKind PrepareScalarCast(ExprResult &src, QualType destType);

/// Build an altivec or OpenCL literal.
ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
                              SourceLocation RParenLoc, Expr *E,
                              TypeSourceInfo *TInfo);

ExprResult MaybeConvertParenListExprToParenExpr(Scope *S, Expr *ME);

ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc,
                                ParsedType Ty,
                                SourceLocation RParenLoc,
                                Expr *InitExpr);

ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
                                    TypeSourceInfo *TInfo,
                                    SourceLocation RParenLoc,
                                    Expr *LiteralExpr);

ExprResult ActOnInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult BuildInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult ActOnDesignatedInitializer(Designation &Desig,
                                      SourceLocation EqualOrColonLoc,
                                      bool GNUSyntax,
                                      ExprResult Init);

5492private:
static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);

5495public:
ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc,
                      tok::TokenKind Kind, Expr *LHSExpr, Expr *RHSExpr);
ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc,
                      BinaryOperatorKind Opc, Expr *LHSExpr, Expr *RHSExpr);
ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
                              Expr *LHSExpr, Expr *RHSExpr);
void LookupBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
                 UnresolvedSetImpl &Functions);

void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);

/// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
/// in the case of a the GNU conditional expr extension.
ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
                              SourceLocation ColonLoc,
                              Expr *CondExpr, Expr *LHSExpr, Expr *RHSExpr);

/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                          LabelDecl *TheDecl);

void ActOnStartStmtExpr();
ExprResult ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,
                         SourceLocation RPLoc);
ExprResult BuildStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                         SourceLocation RPLoc, unsigned TemplateDepth);
// Handle the final expression in a statement expression.
ExprResult ActOnStmtExprResult(ExprResult E);
void ActOnStmtExprError();

// __builtin_offsetof(type, identifier(.identifier|[expr])*)
struct OffsetOfComponent {
  SourceLocation LocStart, LocEnd;
  bool isBrackets;  // true if [expr], false if .ident
  union {
    IdentifierInfo *IdentInfo;
    Expr *E;
  } U;
};

/// __builtin_offsetof(type, a.b[123][456].c)
ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
                                TypeSourceInfo *TInfo,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);
ExprResult ActOnBuiltinOffsetOf(Scope *S,
                                SourceLocation BuiltinLoc,
                                SourceLocation TypeLoc,
                                ParsedType ParsedArgTy,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);

// __builtin_choose_expr(constExpr, expr1, expr2)
ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc,
                           Expr *CondExpr, Expr *LHSExpr,
                           Expr *RHSExpr, SourceLocation RPLoc);

// __builtin_va_arg(expr, type)
ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
                      SourceLocation RPLoc);
ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
                          TypeSourceInfo *TInfo, SourceLocation RPLoc);

// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FILE(),
// __builtin_COLUMN()
ExprResult ActOnSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc,
                              SourceLocation RPLoc);

// Build a potentially resolved SourceLocExpr.
ExprResult BuildSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc, SourceLocation RPLoc,
                              DeclContext *ParentContext);

// __null
ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);

bool CheckCaseExpression(Expr *E);

/// Describes the result of an "if-exists" condition check.
enum IfExistsResult {
  /// The symbol exists.
  IER_Exists,

  /// The symbol does not exist.
  IER_DoesNotExist,

  /// The name is a dependent name, so the results will differ
  /// from one instantiation to the next.
  IER_Dependent,

  /// An error occurred.
  IER_Error
};

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
                             const DeclarationNameInfo &TargetNameInfo);

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, SourceLocation KeywordLoc,
                             bool IsIfExists, CXXScopeSpec &SS,
                             UnqualifiedId &Name);

StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      NestedNameSpecifierLoc QualifierLoc,
                                      DeclarationNameInfo NameInfo,
                                      Stmt *Nested);
StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      CXXScopeSpec &SS, UnqualifiedId &Name,
                                      Stmt *Nested);

//===------------------------- "Block" Extension ------------------------===//

/// ActOnBlockStart - This callback is invoked when a block literal is
/// started.
void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockArguments - This callback allows processing of block arguments.
/// If there are no arguments, this is still invoked.
void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
                         Scope *CurScope);

/// ActOnBlockError - If there is an error parsing a block, this callback
/// is invoked to pop the information about the block from the action impl.
void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockStmtExpr - This is called when the body of a block statement
/// literal was successfully completed.  ^(int x){...}
ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
                              Scope *CurScope);

//===---------------------------- Clang Extensions ----------------------===//

/// __builtin_convertvector(...)
ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
                                  SourceLocation BuiltinLoc,
                                  SourceLocation RParenLoc);

//===---------------------------- OpenCL Features -----------------------===//

/// __builtin_astype(...)
ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
                           SourceLocation BuiltinLoc,
                           SourceLocation RParenLoc);
ExprResult BuildAsTypeExpr(Expr *E, QualType DestTy,
                           SourceLocation BuiltinLoc,
                           SourceLocation RParenLoc);

//===---------------------------- C++ Features --------------------------===//

// Act on C++ namespaces
Decl *ActOnStartNamespaceDef(Scope *S, SourceLocation InlineLoc,
                             SourceLocation NamespaceLoc,
                             SourceLocation IdentLoc, IdentifierInfo *Ident,
                             SourceLocation LBrace,
                             const ParsedAttributesView &AttrList,
                             UsingDirectiveDecl *&UsingDecl);
void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);

NamespaceDecl *getStdNamespace() const;
NamespaceDecl *getOrCreateStdNamespace();

NamespaceDecl *lookupStdExperimentalNamespace();

CXXRecordDecl *getStdBadAlloc() const;
EnumDecl *getStdAlignValT() const;

5666private:
// A cache representing if we've fully checked the various comparison category
// types stored in ASTContext. The bit-index corresponds to the integer value
// of a ComparisonCategoryType enumerator.
llvm::SmallBitVector FullyCheckedComparisonCategories;

ValueDecl *tryLookupCtorInitMemberDecl(CXXRecordDecl *ClassDecl,
                                       CXXScopeSpec &SS,
                                       ParsedType TemplateTypeTy,
                                       IdentifierInfo *MemberOrBase);

5677public:
enum class ComparisonCategoryUsage {
  /// The '<=>' operator was used in an expression and a builtin operator
  /// was selected.
  OperatorInExpression,
  /// A defaulted 'operator<=>' needed the comparison category. This
  /// typically only applies to 'std::strong_ordering', due to the implicit
  /// fallback return value.
  DefaultedOperator,
};

/// Lookup the specified comparison category types in the standard
///   library, an check the VarDecls possibly returned by the operator<=>
///   builtins for that type.
///
/// \return The type of the comparison category type corresponding to the
///   specified Kind, or a null type if an error occurs
QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
                                     SourceLocation Loc,
                                     ComparisonCategoryUsage Usage);

/// Tests whether Ty is an instance of std::initializer_list and, if
/// it is and Element is not NULL, assigns the element type to Element.
bool isStdInitializerList(QualType Ty, QualType *Element);

/// Looks for the std::initializer_list template and instantiates it
/// with Element, or emits an error if it's not found.
///
/// \returns The instantiated template, or null on error.
QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);

/// Determine whether Ctor is an initializer-list constructor, as
/// defined in [dcl.init.list]p2.
bool isInitListConstructor(const FunctionDecl *Ctor);

Decl *ActOnUsingDirective(Scope *CurScope, SourceLocation UsingLoc,
                          SourceLocation NamespcLoc, CXXScopeSpec &SS,
                          SourceLocation IdentLoc,
                          IdentifierInfo *NamespcName,
                          const ParsedAttributesView &AttrList);

void PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir);

Decl *ActOnNamespaceAliasDef(Scope *CurScope,
                             SourceLocation NamespaceLoc,
                             SourceLocation AliasLoc,
                             IdentifierInfo *Alias,
                             CXXScopeSpec &SS,
                             SourceLocation IdentLoc,
                             IdentifierInfo *Ident);

void FilterUsingLookup(Scope *S, LookupResult &lookup);
void HideUsingShadowDecl(Scope *S, UsingShadowDecl *Shadow);
bool CheckUsingShadowDecl(BaseUsingDecl *BUD, NamedDecl *Target,
                          const LookupResult &PreviousDecls,
                          UsingShadowDecl *&PrevShadow);
UsingShadowDecl *BuildUsingShadowDecl(Scope *S, BaseUsingDecl *BUD,
                                      NamedDecl *Target,
                                      UsingShadowDecl *PrevDecl);

bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
                                 bool HasTypenameKeyword,
                                 const CXXScopeSpec &SS,
                                 SourceLocation NameLoc,
                                 const LookupResult &Previous);
bool CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
                             const CXXScopeSpec &SS,
                             const DeclarationNameInfo &NameInfo,
                             SourceLocation NameLoc,
                             const LookupResult *R = nullptr,
                             const UsingDecl *UD = nullptr);

NamedDecl *BuildUsingDeclaration(
    Scope *S, AccessSpecifier AS, SourceLocation UsingLoc,
    bool HasTypenameKeyword, SourceLocation TypenameLoc, CXXScopeSpec &SS,
    DeclarationNameInfo NameInfo, SourceLocation EllipsisLoc,
    const ParsedAttributesView &AttrList, bool IsInstantiation,
    bool IsUsingIfExists);
NamedDecl *BuildUsingEnumDeclaration(Scope *S, AccessSpecifier AS,
                                     SourceLocation UsingLoc,
                                     SourceLocation EnumLoc,
                                     SourceLocation NameLoc, EnumDecl *ED);
NamedDecl *BuildUsingPackDecl(NamedDecl *InstantiatedFrom,
                              ArrayRef<NamedDecl *> Expansions);

bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);

/// Given a derived-class using shadow declaration for a constructor and the
/// correspnding base class constructor, find or create the implicit
/// synthesized derived class constructor to use for this initialization.
CXXConstructorDecl *
findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
                          ConstructorUsingShadowDecl *DerivedShadow);

Decl *ActOnUsingDeclaration(Scope *CurScope, AccessSpecifier AS,
                            SourceLocation UsingLoc,
                            SourceLocation TypenameLoc, CXXScopeSpec &SS,
                            UnqualifiedId &Name, SourceLocation EllipsisLoc,
                            const ParsedAttributesView &AttrList);
Decl *ActOnUsingEnumDeclaration(Scope *CurScope, AccessSpecifier AS,
                                SourceLocation UsingLoc,
                                SourceLocation EnumLoc, const DeclSpec &);
Decl *ActOnAliasDeclaration(Scope *CurScope, AccessSpecifier AS,
                            MultiTemplateParamsArg TemplateParams,
                            SourceLocation UsingLoc, UnqualifiedId &Name,
                            const ParsedAttributesView &AttrList,
                            TypeResult Type, Decl *DeclFromDeclSpec);

/// BuildCXXConstructExpr - Creates a complete call to a constructor,
/// including handling of its default argument expressions.
///
/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

/// Build a CXXConstructExpr whose constructor has already been resolved if
/// it denotes an inherited constructor.
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
// the constructor can be elidable?
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs, bool HadMultipleCandidates,
                      bool IsListInitialization,
                      bool IsStdInitListInitialization, bool RequiresZeroInit,
                      unsigned ConstructKind, SourceRange ParenRange);

ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);


/// Instantiate or parse a C++ default argument expression as necessary.
/// Return true on error.
bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
                            ParmVarDecl *Param);

/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
/// the default expr if needed.
ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc,
                                  FunctionDecl *FD,
                                  ParmVarDecl *Param);

/// FinalizeVarWithDestructor - Prepare for calling destructor on the
/// constructed variable.
void FinalizeVarWithDestructor(VarDecl *VD, const RecordType *DeclInitType);

/// Helper class that collects exception specifications for
/// implicitly-declared special member functions.
class ImplicitExceptionSpecification {
  // Pointer to allow copying
  Sema *Self;
  // We order exception specifications thus:
  // noexcept is the most restrictive, but is only used in C++11.
  // throw() comes next.
  // Then a throw(collected exceptions)
  // Finally no specification, which is expressed as noexcept(false).
  // throw(...) is used instead if any called function uses it.
  ExceptionSpecificationType ComputedEST;
  llvm::SmallPtrSet<CanQualType, 4> ExceptionsSeen;
  SmallVector<QualType, 4> Exceptions;

  void ClearExceptions() {
    ExceptionsSeen.clear();
    Exceptions.clear();
  }

public:
  explicit ImplicitExceptionSpecification(Sema &Self)
    : Self(&Self), ComputedEST(EST_BasicNoexcept) {
    if (!Self.getLangOpts().CPlusPlus11)
      ComputedEST = EST_DynamicNone;
  }

  /// Get the computed exception specification type.
  ExceptionSpecificationType getExceptionSpecType() const {
    assert(!isComputedNoexcept(ComputedEST) &&((void)0)
           "noexcept(expr) should not be a possible result")((void)0);
    return ComputedEST;
  }

  /// The number of exceptions in the exception specification.
  unsigned size() const { return Exceptions.size(); }

  /// The set of exceptions in the exception specification.
  const QualType *data() const { return Exceptions.data(); }

  /// Integrate another called method into the collected data.
  void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);

  /// Integrate an invoked expression into the collected data.
  void CalledExpr(Expr *E) { CalledStmt(E); }

  /// Integrate an invoked statement into the collected data.
  void CalledStmt(Stmt *S);

  /// Overwrite an EPI's exception specification with this
  /// computed exception specification.
  FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
    FunctionProtoType::ExceptionSpecInfo ESI;
    ESI.Type = getExceptionSpecType();
    if (ESI.Type == EST_Dynamic) {
      ESI.Exceptions = Exceptions;
    } else if (ESI.Type == EST_None) {
      /// C++11 [except.spec]p14:
      ///   The exception-specification is noexcept(false) if the set of
      ///   potential exceptions of the special member function contains "any"
      ESI.Type = EST_NoexceptFalse;
      ESI.NoexceptExpr = Self->ActOnCXXBoolLiteral(SourceLocation(),
                                                   tok::kw_false).get();
    }
    return ESI;
  }
};

/// Evaluate the implicit exception specification for a defaulted
/// special member function.
void EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD);

/// Check the given noexcept-specifier, convert its expression, and compute
/// the appropriate ExceptionSpecificationType.
ExprResult ActOnNoexceptSpec(SourceLocation NoexceptLoc, Expr *NoexceptExpr,
                             ExceptionSpecificationType &EST);

/// Check the given exception-specification and update the
/// exception specification information with the results.
void checkExceptionSpecification(bool IsTopLevel,
                                 ExceptionSpecificationType EST,
                                 ArrayRef<ParsedType> DynamicExceptions,
                                 ArrayRef<SourceRange> DynamicExceptionRanges,
                                 Expr *NoexceptExpr,
                                 SmallVectorImpl<QualType> &Exceptions,
                                 FunctionProtoType::ExceptionSpecInfo &ESI);

/// Determine if we're in a case where we need to (incorrectly) eagerly
/// parse an exception specification to work around a libstdc++ bug.
bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);

/// Add an exception-specification to the given member function
/// (or member function template). The exception-specification was parsed
/// after the method itself was declared.
void actOnDelayedExceptionSpecification(Decl *Method,
       ExceptionSpecificationType EST,
       SourceRange SpecificationRange,
       ArrayRef<ParsedType> DynamicExceptions,
       ArrayRef<SourceRange> DynamicExceptionRanges,
       Expr *NoexceptExpr);

class InheritedConstructorInfo;

/// Determine if a special member function should have a deleted
/// definition when it is defaulted.
bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMember CSM,
                               InheritedConstructorInfo *ICI = nullptr,
                               bool Diagnose = false);

/// Produce notes explaining why a defaulted function was defined as deleted.
void DiagnoseDeletedDefaultedFunction(FunctionDecl *FD);

/// Declare the implicit default constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// default constructor will be added.
///
/// \returns The implicitly-declared default constructor.
CXXConstructorDecl *DeclareImplicitDefaultConstructor(
                                                   CXXRecordDecl *ClassDecl);

/// DefineImplicitDefaultConstructor - Checks for feasibility of
/// defining this constructor as the default constructor.
void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
                                      CXXConstructorDecl *Constructor);

/// Declare the implicit destructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// destructor will be added.
///
/// \returns The implicitly-declared destructor.
CXXDestructorDecl *DeclareImplicitDestructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitDestructor - Checks for feasibility of
/// defining this destructor as the default destructor.
void DefineImplicitDestructor(SourceLocation CurrentLocation,
                              CXXDestructorDecl *Destructor);

/// Build an exception spec for destructors that don't have one.
///
/// C++11 says that user-defined destructors with no exception spec get one
/// that looks as if the destructor was implicitly declared.
void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);

/// Define the specified inheriting constructor.
void DefineInheritingConstructor(SourceLocation UseLoc,
                                 CXXConstructorDecl *Constructor);

/// Declare the implicit copy constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy constructor will be added.
///
/// \returns The implicitly-declared copy constructor.
CXXConstructorDecl *DeclareImplicitCopyConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitCopyConstructor - Checks for feasibility of
/// defining this constructor as the copy constructor.
void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit move constructor for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move constructor will be added.
///
/// \returns The implicitly-declared move constructor, or NULL if it wasn't
/// declared.
CXXConstructorDecl *DeclareImplicitMoveConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitMoveConstructor - Checks for feasibility of
/// defining this constructor as the move constructor.
void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit copy assignment operator for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy assignment operator will be added.
///
/// \returns The implicitly-declared copy assignment operator.
CXXMethodDecl *DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared copy assignment operator.
void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Declare the implicit move assignment operator for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move assignment operator will be added.
///
/// \returns The implicitly-declared move assignment operator, or NULL if it
/// wasn't declared.
CXXMethodDecl *DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared move assignment operator.
void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Force the declaration of any implicitly-declared members of this
/// class.
void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);

/// Check a completed declaration of an implicit special member.
void CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD);

/// Determine whether the given function is an implicitly-deleted
/// special member function.
bool isImplicitlyDeleted(FunctionDecl *FD);

/// Check whether 'this' shows up in the type of a static member
/// function after the (naturally empty) cv-qualifier-seq would be.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);

/// Whether this' shows up in the exception specification of a static
/// member function.
bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);

/// Check whether 'this' shows up in the attributes of the given
/// static member function.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);

/// MaybeBindToTemporary - If the passed in expression has a record type with
/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
/// it simply returns the passed in expression.
ExprResult MaybeBindToTemporary(Expr *E);

/// Wrap the expression in a ConstantExpr if it is a potential immediate
/// invocation.
ExprResult CheckForImmediateInvocation(ExprResult E, FunctionDecl *Decl);

bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
                             QualType DeclInitType, MultiExprArg ArgsPtr,
                             SourceLocation Loc,
                             SmallVectorImpl<Expr *> &ConvertedArgs,
                             bool AllowExplicit = false,
                             bool IsListInitialization = false);

ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
                                        SourceLocation NameLoc,
                                        IdentifierInfo &Name);

ParsedType getConstructorName(IdentifierInfo &II, SourceLocation NameLoc,
                              Scope *S, CXXScopeSpec &SS,
                              bool EnteringContext);
ParsedType getDestructorName(SourceLocation TildeLoc,
                             IdentifierInfo &II, SourceLocation NameLoc,
                             Scope *S, CXXScopeSpec &SS,
                             ParsedType ObjectType,
                             bool EnteringContext);

ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
                                        ParsedType ObjectType);

// Checks that reinterpret casts don't have undefined behavior.
void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
                                    bool IsDereference, SourceRange Range);

// Checks that the vector type should be initialized from a scalar
// by splatting the value rather than populating a single element.
// This is the case for AltiVecVector types as well as with
// AltiVecPixel and AltiVecBool when -faltivec-src-compat=xl is specified.
bool ShouldSplatAltivecScalarInCast(const VectorType *VecTy);

/// ActOnCXXNamedCast - Parse
/// {dynamic,static,reinterpret,const,addrspace}_cast's.
ExprResult ActOnCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             SourceLocation LAngleBracketLoc,
                             Declarator &D,
                             SourceLocation RAngleBracketLoc,
                             SourceLocation LParenLoc,
                             Expr *E,
                             SourceLocation RParenLoc);

ExprResult BuildCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             TypeSourceInfo *Ty,
                             Expr *E,
                             SourceRange AngleBrackets,
                             SourceRange Parens);

ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
                                   ExprResult Operand,
                                   SourceLocation RParenLoc);

ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
                                   Expr *Operand, SourceLocation RParenLoc);

ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXTypeid - Parse typeid( something ).
ExprResult ActOnCXXTypeid(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXUuidof - Parse __uuidof( something ).
ExprResult ActOnCXXUuidof(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

/// Handle a C++1z fold-expression: ( expr op ... op expr ).
ExprResult ActOnCXXFoldExpr(Scope *S, SourceLocation LParenLoc, Expr *LHS,
                            tok::TokenKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc);
ExprResult BuildCXXFoldExpr(UnresolvedLookupExpr *Callee,
                            SourceLocation LParenLoc, Expr *LHS,
                            BinaryOperatorKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc,
                            Optional<unsigned> NumExpansions);
ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
                                 BinaryOperatorKind Operator);

//// ActOnCXXThis -  Parse 'this' pointer.
ExprResult ActOnCXXThis(SourceLocation loc);

/// Build a CXXThisExpr and mark it referenced in the current context.
Expr *BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool IsImplicit);
void MarkThisReferenced(CXXThisExpr *This);

/// Try to retrieve the type of the 'this' pointer.
///
/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
QualType getCurrentThisType();

/// When non-NULL, the C++ 'this' expression is allowed despite the
/// current context not being a non-static member function. In such cases,
/// this provides the type used for 'this'.
QualType CXXThisTypeOverride;

/// RAII object used to temporarily allow the C++ 'this' expression
/// to be used, with the given qualifiers on the current class type.
class CXXThisScopeRAII {
  Sema &S;
  QualType OldCXXThisTypeOverride;
  bool Enabled;

public:
  /// Introduce a new scope where 'this' may be allowed (when enabled),
  /// using the given declaration (which is either a class template or a
  /// class) along with the given qualifiers.
  /// along with the qualifiers placed on '*this'.
  CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
                   bool Enabled = true);

  ~CXXThisScopeRAII();
};

/// Make sure the value of 'this' is actually available in the current
/// context, if it is a potentially evaluated context.
///
/// \param Loc The location at which the capture of 'this' occurs.
///
/// \param Explicit Whether 'this' is explicitly captured in a lambda
/// capture list.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// 'this' that may or may not be used in certain specializations of
/// a nested generic lambda (depending on whether the name resolves to
/// a non-static member function or a static function).
/// \return returns 'true' if failed, 'false' if success.
bool CheckCXXThisCapture(SourceLocation Loc, bool Explicit = false,
    bool BuildAndDiagnose = true,
    const unsigned *const FunctionScopeIndexToStopAt = nullptr,
    bool ByCopy = false);

/// Determine whether the given type is the type of *this that is used
/// outside of the body of a member function for a type that is currently
/// being defined.
bool isThisOutsideMemberFunctionBody(QualType BaseType);

/// ActOnCXXBoolLiteral - Parse {true,false} literals.
ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);


/// ActOnObjCBoolLiteral - Parse {__objc_yes,__objc_no} literals.
ExprResult ActOnObjCBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);

ExprResult
ActOnObjCAvailabilityCheckExpr(llvm::ArrayRef<AvailabilitySpec> AvailSpecs,
                               SourceLocation AtLoc, SourceLocation RParen);

/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);

//// ActOnCXXThrow -  Parse throw expressions.
ExprResult ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *expr);
ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
                         bool IsThrownVarInScope);
bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);

/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
                                     SourceLocation LParenOrBraceLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenOrBraceLoc,
                                     bool ListInitialization);

ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
                                     SourceLocation LParenLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenLoc,
                                     bool ListInitialization);

/// ActOnCXXNew - Parsed a C++ 'new' expression.
ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens, Declarator &D,
                       Expr *Initializer);
ExprResult BuildCXXNew(SourceRange Range, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens,
                       QualType AllocType,
                       TypeSourceInfo *AllocTypeInfo,
                       Optional<Expr *> ArraySize,
                       SourceRange DirectInitRange,
                       Expr *Initializer);

/// Determine whether \p FD is an aligned allocation or deallocation
/// function that is unavailable.
bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;

/// Produce diagnostics if \p FD is an aligned allocation or deallocation
/// function that is unavailable.
void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
                                          SourceLocation Loc);

bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                        SourceRange R);

/// The scope in which to find allocation functions.
enum AllocationFunctionScope {
  /// Only look for allocation functions in the global scope.
  AFS_Global,
  /// Only look for allocation functions in the scope of the
  /// allocated class.
  AFS_Class,
  /// Look for allocation functions in both the global scope
  /// and in the scope of the allocated class.
  AFS_Both
};

/// Finds the overloads of operator new and delete that are appropriate
/// for the allocation.
bool FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
                             AllocationFunctionScope NewScope,
                             AllocationFunctionScope DeleteScope,
                             QualType AllocType, bool IsArray,
                             bool &PassAlignment, MultiExprArg PlaceArgs,
                             FunctionDecl *&OperatorNew,
                             FunctionDecl *&OperatorDelete,
                             bool Diagnose = true);
void DeclareGlobalNewDelete();
void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
                                     ArrayRef<QualType> Params);

bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
                              DeclarationName Name, FunctionDecl* &Operator,
                              bool Diagnose = true);
FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
                                            bool CanProvideSize,
                                            bool Overaligned,
                                            DeclarationName Name);
FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
                                                    CXXRecordDecl *RD);

/// ActOnCXXDelete - Parsed a C++ 'delete' expression
ExprResult ActOnCXXDelete(SourceLocation StartLoc,
                          bool UseGlobal, bool ArrayForm,
                          Expr *Operand);
void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
                          bool IsDelete, bool CallCanBeVirtual,
                          bool WarnOnNonAbstractTypes,
                          SourceLocation DtorLoc);

ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
                             Expr *Operand, SourceLocation RParen);
ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
                                SourceLocation RParen);

/// Parsed one of the type trait support pseudo-functions.
ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<ParsedType> Args,
                          SourceLocation RParenLoc);
ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<TypeSourceInfo *> Args,
                          SourceLocation RParenLoc);

/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
/// pseudo-functions.
ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               ParsedType LhsTy,
                               Expr *DimExpr,
                               SourceLocation RParen);

ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               TypeSourceInfo *TSInfo,
                               Expr *DimExpr,
                               SourceLocation RParen);

/// ActOnExpressionTrait - Parsed one of the unary type trait support
/// pseudo-functions.
ExprResult ActOnExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult BuildExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult ActOnStartCXXMemberReference(Scope *S,
                                        Expr *Base,
                                        SourceLocation OpLoc,
                                        tok::TokenKind OpKind,
                                        ParsedType &ObjectType,
                                        bool &MayBePseudoDestructor);

ExprResult BuildPseudoDestructorExpr(Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     const CXXScopeSpec &SS,
                                     TypeSourceInfo *ScopeType,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                   PseudoDestructorTypeStorage DestroyedType);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     CXXScopeSpec &SS,
                                     UnqualifiedId &FirstTypeName,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                     UnqualifiedId &SecondTypeName);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     SourceLocation TildeLoc,
                                     const DeclSpec& DS);

/// MaybeCreateExprWithCleanups - If the current full-expression
/// requires any cleanups, surround it with a ExprWithCleanups node.
/// Otherwise, just returns the passed-in expression.
Expr *MaybeCreateExprWithCleanups(Expr *SubExpr);
Stmt *MaybeCreateStmtWithCleanups(Stmt *SubStmt);
ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);

MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
                               bool BoundToLvalueReference);

ExprResult ActOnFinishFullExpr(Expr *Expr, bool DiscardedValue) {
  return ActOnFinishFullExpr(
      Expr, Expr ? Expr->getExprLoc() : SourceLocation(), DiscardedValue);
}
ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
                               bool DiscardedValue, bool IsConstexpr = false);
StmtResult ActOnFinishFullStmt(Stmt *Stmt);

// Marks SS invalid if it represents an incomplete type.
bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);
// Complete an enum decl, maybe without a scope spec.
bool RequireCompleteEnumDecl(EnumDecl *D, SourceLocation L,
                             CXXScopeSpec *SS = nullptr);

DeclContext *computeDeclContext(QualType T);
DeclContext *computeDeclContext(const CXXScopeSpec &SS,
                                bool EnteringContext = false);
bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier *NNS);

/// The parser has parsed a global nested-name-specifier '::'.
///
/// \param CCLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);

/// The parser has parsed a '__super' nested-name-specifier.
///
/// \param SuperLoc The location of the '__super' keyword.
///
/// \param ColonColonLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
                              SourceLocation ColonColonLoc, CXXScopeSpec &SS);

bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
                                     bool *CanCorrect = nullptr);
NamedDecl *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);

/// Keeps information about an identifier in a nested-name-spec.
///
struct NestedNameSpecInfo {
  /// The type of the object, if we're parsing nested-name-specifier in
  /// a member access expression.
  ParsedType ObjectType;

  /// The identifier preceding the '::'.
  IdentifierInfo *Identifier;

  /// The location of the identifier.
  SourceLocation IdentifierLoc;

  /// The location of the '::'.
  SourceLocation CCLoc;

  /// Creates info object for the most typical case.
  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
           SourceLocation ColonColonLoc, ParsedType ObjectType = ParsedType())
    : ObjectType(ObjectType), Identifier(II), IdentifierLoc(IdLoc),
      CCLoc(ColonColonLoc) {
  }

  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
                     SourceLocation ColonColonLoc, QualType ObjectType)
    : ObjectType(ParsedType::make(ObjectType)), Identifier(II),
      IdentifierLoc(IdLoc), CCLoc(ColonColonLoc) {
  }
};

bool isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
                                  NestedNameSpecInfo &IdInfo);

bool BuildCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 NamedDecl *ScopeLookupResult,
                                 bool ErrorRecoveryLookup,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

/// The parser has parsed a nested-name-specifier 'identifier::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param IdInfo Parser information about an identifier in the
/// nested-name-spec.
///
/// \param EnteringContext Whether we're entering the context nominated by
/// this nested-name-specifier.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param ErrorRecoveryLookup If true, then this method is called to improve
/// error recovery. In this case do not emit error message.
///
/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
/// are allowed.  The bool value pointed by this parameter is set to 'true'
/// if the identifier is treated as if it was followed by ':', not '::'.
///
/// \param OnlyNamespace If true, only considers namespaces in lookup.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 bool ErrorRecoveryLookup = false,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

ExprResult ActOnDecltypeExpression(Expr *E);

bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
                                         const DeclSpec &DS,
                                         SourceLocation ColonColonLoc);

bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
                               NestedNameSpecInfo &IdInfo,
                               bool EnteringContext);

/// The parser has parsed a nested-name-specifier
/// 'template[opt] template-name < template-args >::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param TemplateKWLoc the location of the 'template' keyword, if any.
/// \param TemplateName the template name.
/// \param TemplateNameLoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
/// \param CCLoc The location of the '::'.
///
/// \param EnteringContext Whether we're entering the context of the
/// nested-name-specifier.
///
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 TemplateTy TemplateName,
                                 SourceLocation TemplateNameLoc,
                                 SourceLocation LAngleLoc,
                                 ASTTemplateArgsPtr TemplateArgs,
                                 SourceLocation RAngleLoc,
                                 SourceLocation CCLoc,
                                 bool EnteringContext);

/// Given a C++ nested-name-specifier, produce an annotation value
/// that the parser can use later to reconstruct the given
/// nested-name-specifier.
///
/// \param SS A nested-name-specifier.
///
/// \returns A pointer containing all of the information in the
/// nested-name-specifier \p SS.
void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);

/// Given an annotation pointer for a nested-name-specifier, restore
/// the nested-name-specifier structure.
///
/// \param Annotation The annotation pointer, produced by
/// \c SaveNestedNameSpecifierAnnotation().
///
/// \param AnnotationRange The source range corresponding to the annotation.
///
/// \param SS The nested-name-specifier that will be updated with the contents
/// of the annotation pointer.
void RestoreNestedNameSpecifierAnnotation(void *Annotation,
                                          SourceRange AnnotationRange,
                                          CXXScopeSpec &SS);

bool ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
/// scope or nested-name-specifier) is parsed, part of a declarator-id.
/// After this method is called, according to [C++ 3.4.3p3], names should be
/// looked up in the declarator-id's scope, until the declarator is parsed and
/// ActOnCXXExitDeclaratorScope is called.
/// The 'SS' should be a non-empty valid CXXScopeSpec.
bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);

/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
/// Used to indicate that names should revert to being looked up in the
/// defining scope.
void ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
/// initializer for the declaration 'Dcl'.
/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
/// static data member of class X, names should be looked up in the scope of
/// class X.
void ActOnCXXEnterDeclInitializer(Scope *S, Decl *Dcl);

/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
/// initializer for the declaration 'Dcl'.
void ActOnCXXExitDeclInitializer(Scope *S, Decl *Dcl);

/// Create a new lambda closure type.
CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
                                       TypeSourceInfo *Info,
                                       bool KnownDependent,
                                       LambdaCaptureDefault CaptureDefault);

/// Start the definition of a lambda expression.
CXXMethodDecl *startLambdaDefinition(CXXRecordDecl *Class,
                                     SourceRange IntroducerRange,
                                     TypeSourceInfo *MethodType,
                                     SourceLocation EndLoc,
                                     ArrayRef<ParmVarDecl *> Params,
                                     ConstexprSpecKind ConstexprKind,
                                     Expr *TrailingRequiresClause);

/// Number lambda for linkage purposes if necessary.
void handleLambdaNumbering(
    CXXRecordDecl *Class, CXXMethodDecl *Method,
    Optional<std::tuple<bool, unsigned, unsigned, Decl *>> Mangling = None);

/// Endow the lambda scope info with the relevant properties.
void buildLambdaScope(sema::LambdaScopeInfo *LSI,
                      CXXMethodDecl *CallOperator,
                      SourceRange IntroducerRange,
                      LambdaCaptureDefault CaptureDefault,
                      SourceLocation CaptureDefaultLoc,
                      bool ExplicitParams,
                      bool ExplicitResultType,
                      bool Mutable);

/// Perform initialization analysis of the init-capture and perform
/// any implicit conversions such as an lvalue-to-rvalue conversion if
/// not being used to initialize a reference.
ParsedType actOnLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    IdentifierInfo *Id, LambdaCaptureInitKind InitKind, Expr *&Init) {
  return ParsedType::make(buildLambdaInitCaptureInitialization(
      Loc, ByRef, EllipsisLoc, None, Id,
      InitKind != LambdaCaptureInitKind::CopyInit, Init));
}
QualType buildLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    Optional<unsigned> NumExpansions, IdentifierInfo *Id, bool DirectInit,
    Expr *&Init);

/// Create a dummy variable within the declcontext of the lambda's
///  call operator, for name lookup purposes for a lambda init capture.
///
///  CodeGen handles emission of lambda captures, ignoring these dummy
///  variables appropriately.
VarDecl *createLambdaInitCaptureVarDecl(SourceLocation Loc,
                                        QualType InitCaptureType,
                                        SourceLocation EllipsisLoc,
                                        IdentifierInfo *Id,
                                        unsigned InitStyle, Expr *Init);

/// Add an init-capture to a lambda scope.
void addInitCapture(sema::LambdaScopeInfo *LSI, VarDecl *Var);

/// Note that we have finished the explicit captures for the
/// given lambda.
void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);

/// \brief This is called after parsing the explicit template parameter list
/// on a lambda (if it exists) in C++2a.
void ActOnLambdaExplicitTemplateParameterList(SourceLocation LAngleLoc,
                                              ArrayRef<NamedDecl *> TParams,
                                              SourceLocation RAngleLoc,
                                              ExprResult RequiresClause);

/// Introduce the lambda parameters into scope.
void addLambdaParameters(
    ArrayRef<LambdaIntroducer::LambdaCapture> Captures,
    CXXMethodDecl *CallOperator, Scope *CurScope);

/// Deduce a block or lambda's return type based on the return
/// statements present in the body.
void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);

/// ActOnStartOfLambdaDefinition - This is called just before we start
/// parsing the body of a lambda; it analyzes the explicit captures and
/// arguments, and sets up various data-structures for the body of the
/// lambda.
void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
                                  Declarator &ParamInfo, Scope *CurScope);

/// ActOnLambdaError - If there is an error parsing a lambda, this callback
/// is invoked to pop the information about the lambda.
void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
                      bool IsInstantiation = false);

/// ActOnLambdaExpr - This is called when the body of a lambda expression
/// was successfully completed.
ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body,
                           Scope *CurScope);

/// Does copying/destroying the captured variable have side effects?
bool CaptureHasSideEffects(const sema::Capture &From);

/// Diagnose if an explicit lambda capture is unused. Returns true if a
/// diagnostic is emitted.
bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
                                 const sema::Capture &From);

/// Build a FieldDecl suitable to hold the given capture.
FieldDecl *BuildCaptureField(RecordDecl *RD, const sema::Capture &Capture);

/// Initialize the given capture with a suitable expression.
ExprResult BuildCaptureInit(const sema::Capture &Capture,
                            SourceLocation ImplicitCaptureLoc,
                            bool IsOpenMPMapping = false);

/// Complete a lambda-expression having processed and attached the
/// lambda body.
ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                           sema::LambdaScopeInfo *LSI);

/// Get the return type to use for a lambda's conversion function(s) to
/// function pointer type, given the type of the call operator.
QualType
getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType,
                                      CallingConv CC);

/// Define the "body" of the conversion from a lambda object to a
/// function pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToFunctionPointerConversion(
       SourceLocation CurrentLoc, CXXConversionDecl *Conv);

/// Define the "body" of the conversion from a lambda object to a
/// block pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
                                                  CXXConversionDecl *Conv);

ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
                                         SourceLocation ConvLocation,
                                         CXXConversionDecl *Conv,
                                         Expr *Src);

/// Check whether the given expression is a valid constraint expression.
/// A diagnostic is emitted if it is not, false is returned, and
/// PossibleNonPrimary will be set to true if the failure might be due to a
/// non-primary expression being used as an atomic constraint.
bool CheckConstraintExpression(const Expr *CE, Token NextToken = Token(),
                               bool *PossibleNonPrimary = nullptr,
                               bool IsTrailingRequiresClause = false);

6803private:
/// Caches pairs of template-like decls whose associated constraints were
/// checked for subsumption and whether or not the first's constraints did in
/// fact subsume the second's.
llvm::DenseMap<std::pair<NamedDecl *, NamedDecl *>, bool> SubsumptionCache;
/// Caches the normalized associated constraints of declarations (concepts or
/// constrained declarations). If an error occurred while normalizing the
/// associated constraints of the template or concept, nullptr will be cached
/// here.
llvm::DenseMap<NamedDecl *, NormalizedConstraint *>
    NormalizationCache;

llvm::ContextualFoldingSet<ConstraintSatisfaction, const ASTContext &>
    SatisfactionCache;

6818public:
const NormalizedConstraint *
getNormalizedAssociatedConstraints(
    NamedDecl *ConstrainedDecl, ArrayRef<const Expr *> AssociatedConstraints);

/// \brief Check whether the given declaration's associated constraints are
/// at least as constrained than another declaration's according to the
/// partial ordering of constraints.
///
/// \param Result If no error occurred, receives the result of true if D1 is
/// at least constrained than D2, and false otherwise.
///
/// \returns true if an error occurred, false otherwise.
bool IsAtLeastAsConstrained(NamedDecl *D1, ArrayRef<const Expr *> AC1,
                            NamedDecl *D2, ArrayRef<const Expr *> AC2,
                            bool &Result);

/// If D1 was not at least as constrained as D2, but would've been if a pair
/// of atomic constraints involved had been declared in a concept and not
/// repeated in two separate places in code.
/// \returns true if such a diagnostic was emitted, false otherwise.
bool MaybeEmitAmbiguousAtomicConstraintsDiagnostic(NamedDecl *D1,
    ArrayRef<const Expr *> AC1, NamedDecl *D2, ArrayRef<const Expr *> AC2);

/// \brief Check whether the given list of constraint expressions are
/// satisfied (as if in a 'conjunction') given template arguments.
/// \param Template the template-like entity that triggered the constraints
/// check (either a concept or a constrained entity).
/// \param ConstraintExprs a list of constraint expressions, treated as if
/// they were 'AND'ed together.
/// \param TemplateArgs the list of template arguments to substitute into the
/// constraint expression.
/// \param TemplateIDRange The source range of the template id that
/// caused the constraints check.
/// \param Satisfaction if true is returned, will contain details of the
/// satisfaction, with enough information to diagnose an unsatisfied
/// expression.
/// \returns true if an error occurred and satisfaction could not be checked,
/// false otherwise.
bool CheckConstraintSatisfaction(
    const NamedDecl *Template, ArrayRef<const Expr *> ConstraintExprs,
    ArrayRef<TemplateArgument> TemplateArgs,
    SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction);

/// \brief Check whether the given non-dependent constraint expression is
/// satisfied. Returns false and updates Satisfaction with the satisfaction
/// verdict if successful, emits a diagnostic and returns true if an error
/// occured and satisfaction could not be determined.
///
/// \returns true if an error occurred, false otherwise.
bool CheckConstraintSatisfaction(const Expr *ConstraintExpr,
                                 ConstraintSatisfaction &Satisfaction);

/// Check whether the given function decl's trailing requires clause is
/// satisfied, if any. Returns false and updates Satisfaction with the
/// satisfaction verdict if successful, emits a diagnostic and returns true if
/// an error occured and satisfaction could not be determined.
///
/// \returns true if an error occurred, false otherwise.
bool CheckFunctionConstraints(const FunctionDecl *FD,
                              ConstraintSatisfaction &Satisfaction,
                              SourceLocation UsageLoc = SourceLocation());


/// \brief Ensure that the given template arguments satisfy the constraints
/// associated with the given template, emitting a diagnostic if they do not.
///
/// \param Template The template to which the template arguments are being
/// provided.
///
/// \param TemplateArgs The converted, canonicalized template arguments.
///
/// \param TemplateIDRange The source range of the template id that
/// caused the constraints check.
///
/// \returns true if the constrains are not satisfied or could not be checked
/// for satisfaction, false if the constraints are satisfied.
bool EnsureTemplateArgumentListConstraints(TemplateDecl *Template,
                                     ArrayRef<TemplateArgument> TemplateArgs,
                                           SourceRange TemplateIDRange);

/// \brief Emit diagnostics explaining why a constraint expression was deemed
/// unsatisfied.
/// \param First whether this is the first time an unsatisfied constraint is
/// diagnosed for this error.
void
DiagnoseUnsatisfiedConstraint(const ConstraintSatisfaction &Satisfaction,
                              bool First = true);

/// \brief Emit diagnostics explaining why a constraint expression was deemed
/// unsatisfied.
void
DiagnoseUnsatisfiedConstraint(const ASTConstraintSatisfaction &Satisfaction,
                              bool First = true);

// ParseObjCStringLiteral - Parse Objective-C string literals.
ExprResult ParseObjCStringLiteral(SourceLocation *AtLocs,
                                  ArrayRef<Expr *> Strings);

ExprResult BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S);

/// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
/// numeric literal expression. Type of the expression will be "NSNumber *"
/// or "id" if NSNumber is unavailable.
ExprResult BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number);
ExprResult ActOnObjCBoolLiteral(SourceLocation AtLoc, SourceLocation ValueLoc,
                                bool Value);
ExprResult BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements);

/// BuildObjCBoxedExpr - builds an ObjCBoxedExpr AST node for the
/// '@' prefixed parenthesized expression. The type of the expression will
/// either be "NSNumber *", "NSString *" or "NSValue *" depending on the type
/// of ValueType, which is allowed to be a built-in numeric type, "char *",
/// "const char *" or C structure with attribute 'objc_boxable'.
ExprResult BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr);

ExprResult BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
                                        Expr *IndexExpr,
                                        ObjCMethodDecl *getterMethod,
                                        ObjCMethodDecl *setterMethod);

ExprResult BuildObjCDictionaryLiteral(SourceRange SR,
                             MutableArrayRef<ObjCDictionaryElement> Elements);

ExprResult BuildObjCEncodeExpression(SourceLocation AtLoc,
                                TypeSourceInfo *EncodedTypeInfo,
                                SourceLocation RParenLoc);
ExprResult BuildCXXMemberCallExpr(Expr *Exp, NamedDecl *FoundDecl,
                                  CXXConversionDecl *Method,
                                  bool HadMultipleCandidates);

ExprResult ParseObjCEncodeExpression(SourceLocation AtLoc,
                                     SourceLocation EncodeLoc,
                                     SourceLocation LParenLoc,
                                     ParsedType Ty,
                                     SourceLocation RParenLoc);

/// ParseObjCSelectorExpression - Build selector expression for \@selector
ExprResult ParseObjCSelectorExpression(Selector Sel,
                                       SourceLocation AtLoc,
                                       SourceLocation SelLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation RParenLoc,
                                       bool WarnMultipleSelectors);

/// ParseObjCProtocolExpression - Build protocol expression for \@protocol
ExprResult ParseObjCProtocolExpression(IdentifierInfo * ProtocolName,
                                       SourceLocation AtLoc,
                                       SourceLocation ProtoLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation ProtoIdLoc,
                                       SourceLocation RParenLoc);

//===--------------------------------------------------------------------===//
// C++ Declarations
//
Decl *ActOnStartLinkageSpecification(Scope *S,
                                     SourceLocation ExternLoc,
                                     Expr *LangStr,
                                     SourceLocation LBraceLoc);
Decl *ActOnFinishLinkageSpecification(Scope *S,
                                      Decl *LinkageSpec,
                                      SourceLocation RBraceLoc);


//===--------------------------------------------------------------------===//
// C++ Classes
//
CXXRecordDecl *getCurrentClass(Scope *S, const CXXScopeSpec *SS);
bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
                        const CXXScopeSpec *SS = nullptr);
bool isCurrentClassNameTypo(IdentifierInfo *&II, const CXXScopeSpec *SS);

bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
                          SourceLocation ColonLoc,
                          const ParsedAttributesView &Attrs);

NamedDecl *ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS,
                               Declarator &D,
                               MultiTemplateParamsArg TemplateParameterLists,
                               Expr *BitfieldWidth, const VirtSpecifiers &VS,
                               InClassInitStyle InitStyle);

void ActOnStartCXXInClassMemberInitializer();
void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
                                            SourceLocation EqualLoc,
                                            Expr *Init);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  SourceLocation LParenLoc,
                                  ArrayRef<Expr *> Args,
                                  SourceLocation RParenLoc,
                                  SourceLocation EllipsisLoc);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *InitList,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *Init,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemberInitializer(ValueDecl *Member,
                                     Expr *Init,
                                     SourceLocation IdLoc);

MemInitResult BuildBaseInitializer(QualType BaseType,
                                   TypeSourceInfo *BaseTInfo,
                                   Expr *Init,
                                   CXXRecordDecl *ClassDecl,
                                   SourceLocation EllipsisLoc);

MemInitResult BuildDelegatingInitializer(TypeSourceInfo *TInfo,
                                         Expr *Init,
                                         CXXRecordDecl *ClassDecl);

bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
                              CXXCtorInitializer *Initializer);

bool SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
                         ArrayRef<CXXCtorInitializer *> Initializers = None);

void SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation);


/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
/// mark all the non-trivial destructors of its members and bases as
/// referenced.
void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
                                            CXXRecordDecl *Record);

/// Mark destructors of virtual bases of this class referenced. In the Itanium
/// C++ ABI, this is done when emitting a destructor for any non-abstract
/// class. In the Microsoft C++ ABI, this is done any time a class's
/// destructor is referenced.
void MarkVirtualBaseDestructorsReferenced(
    SourceLocation Location, CXXRecordDecl *ClassDecl,
    llvm::SmallPtrSetImpl<const RecordType *> *DirectVirtualBases = nullptr);

/// Do semantic checks to allow the complete destructor variant to be emitted
/// when the destructor is defined in another translation unit. In the Itanium
/// C++ ABI, destructor variants are emitted together. In the MS C++ ABI, they
/// can be emitted in separate TUs. To emit the complete variant, run a subset
/// of the checks performed when emitting a regular destructor.
void CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
                                    CXXDestructorDecl *Dtor);

/// The list of classes whose vtables have been used within
/// this translation unit, and the source locations at which the
/// first use occurred.
typedef std::pair<CXXRecordDecl*, SourceLocation> VTableUse;

/// The list of vtables that are required but have not yet been
/// materialized.
SmallVector<VTableUse, 16> VTableUses;

/// The set of classes whose vtables have been used within
/// this translation unit, and a bit that will be true if the vtable is
/// required to be emitted (otherwise, it should be emitted only if needed
/// by code generation).
llvm::DenseMap<CXXRecordDecl *, bool> VTablesUsed;

/// Load any externally-stored vtable uses.
void LoadExternalVTableUses();

/// Note that the vtable for the given class was used at the
/// given location.
void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
                    bool DefinitionRequired = false);

/// Mark the exception specifications of all virtual member functions
/// in the given class as needed.
void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
                                           const CXXRecordDecl *RD);

/// MarkVirtualMembersReferenced - Will mark all members of the given
/// CXXRecordDecl referenced.
void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
                                  bool ConstexprOnly = false);

/// Define all of the vtables that have been used in this
/// translation unit and reference any virtual members used by those
/// vtables.
///
/// \returns true if any work was done, false otherwise.
bool DefineUsedVTables();

void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);

void ActOnMemInitializers(Decl *ConstructorDecl,
                          SourceLocation ColonLoc,
                          ArrayRef<CXXCtorInitializer*> MemInits,
                          bool AnyErrors);

/// Check class-level dllimport/dllexport attribute. The caller must
/// ensure that referenceDLLExportedClassMethods is called some point later
/// when all outer classes of Class are complete.
void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);

void referenceDLLExportedClassMethods();

void propagateDLLAttrToBaseClassTemplate(
    CXXRecordDecl *Class, Attr *ClassAttr,
    ClassTemplateSpecializationDecl *BaseTemplateSpec,
    SourceLocation BaseLoc);

/// Add gsl::Pointer attribute to std::container::iterator
/// \param ND The declaration that introduces the name
/// std::container::iterator. \param UnderlyingRecord The record named by ND.
void inferGslPointerAttribute(NamedDecl *ND, CXXRecordDecl *UnderlyingRecord);

/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);

/// Add [[gsl::Pointer]] attributes for std:: types.
void inferGslPointerAttribute(TypedefNameDecl *TD);

void CheckCompletedCXXClass(Scope *S, CXXRecordDecl *Record);

/// Check that the C++ class annoated with "trivial_abi" satisfies all the
/// conditions that are needed for the attribute to have an effect.
void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);

void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
                                       Decl *TagDecl, SourceLocation LBrac,
                                       SourceLocation RBrac,
                                       const ParsedAttributesView &AttrList);
void ActOnFinishCXXMemberDecls();
void ActOnFinishCXXNonNestedClass();

void ActOnReenterCXXMethodParameter(Scope *S, ParmVarDecl *Param);
unsigned ActOnReenterTemplateScope(Decl *Template,
                                   llvm::function_ref<Scope *()> EnterScope);
void ActOnStartDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnStartDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnDelayedCXXMethodParameter(Scope *S, Decl *Param);
void ActOnFinishDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnFinishDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnFinishDelayedMemberInitializers(Decl *Record);
void MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
                              CachedTokens &Toks);
void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
bool IsInsideALocalClassWithinATemplateFunction();

Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   Expr *AssertMessageExpr,
                                   SourceLocation RParenLoc);
Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   StringLiteral *AssertMessageExpr,
                                   SourceLocation RParenLoc,
                                   bool Failed);

FriendDecl *CheckFriendTypeDecl(SourceLocation LocStart,
                                SourceLocation FriendLoc,
                                TypeSourceInfo *TSInfo);
Decl *ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
                          MultiTemplateParamsArg TemplateParams);
NamedDecl *ActOnFriendFunctionDecl(Scope *S, Declarator &D,
                                   MultiTemplateParamsArg TemplateParams);

QualType CheckConstructorDeclarator(Declarator &D, QualType R,
                                    StorageClass& SC);
void CheckConstructor(CXXConstructorDecl *Constructor);
QualType CheckDestructorDeclarator(Declarator &D, QualType R,
                                   StorageClass& SC);
bool CheckDestructor(CXXDestructorDecl *Destructor);
void CheckConversionDeclarator(Declarator &D, QualType &R,
                               StorageClass& SC);
Decl *ActOnConversionDeclarator(CXXConversionDecl *Conversion);
void CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
                                   StorageClass &SC);
void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);

void CheckExplicitlyDefaultedFunction(Scope *S, FunctionDecl *MD);

bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
                                           CXXSpecialMember CSM);
void CheckDelayedMemberExceptionSpecs();

bool CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *MD,
                                        DefaultedComparisonKind DCK);
void DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
                                       FunctionDecl *Spaceship);
void DefineDefaultedComparison(SourceLocation Loc, FunctionDecl *FD,
                               DefaultedComparisonKind DCK);

//===--------------------------------------------------------------------===//
// C++ Derived Classes
//

/// ActOnBaseSpecifier - Parsed a base specifier
CXXBaseSpecifier *CheckBaseSpecifier(CXXRecordDecl *Class,
                                     SourceRange SpecifierRange,
                                     bool Virtual, AccessSpecifier Access,
                                     TypeSourceInfo *TInfo,
                                     SourceLocation EllipsisLoc);

BaseResult ActOnBaseSpecifier(Decl *classdecl,
                              SourceRange SpecifierRange,
                              ParsedAttributes &Attrs,
                              bool Virtual, AccessSpecifier Access,
                              ParsedType basetype,
                              SourceLocation BaseLoc,
                              SourceLocation EllipsisLoc);

bool AttachBaseSpecifiers(CXXRecordDecl *Class,
                          MutableArrayRef<CXXBaseSpecifier *> Bases);
void ActOnBaseSpecifiers(Decl *ClassDecl,
                         MutableArrayRef<CXXBaseSpecifier *> Bases);

bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
                   CXXBasePaths &Paths);

// FIXME: I don't like this name.
void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);

bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  SourceLocation Loc, SourceRange Range,
                                  CXXCastPath *BasePath = nullptr,
                                  bool IgnoreAccess = false);
bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  unsigned InaccessibleBaseID,
                                  unsigned AmbiguousBaseConvID,
                                  SourceLocation Loc, SourceRange Range,
                                  DeclarationName Name,
                                  CXXCastPath *BasePath,
                                  bool IgnoreAccess = false);

std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);

bool CheckOverridingFunctionAttributes(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionReturnType - Checks whether the return types are
/// covariant, according to C++ [class.virtual]p5.
bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
/// spec is a subset of base spec.
bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
                                          const CXXMethodDecl *Old);

bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);

/// CheckOverrideControl - Check C++11 override control semantics.
void CheckOverrideControl(NamedDecl *D);

/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
/// not used in the declaration of an overriding method.
void DiagnoseAbsenceOfOverrideControl(NamedDecl *D, bool Inconsistent);

/// CheckForFunctionMarkedFinal - Checks whether a virtual member function
/// overrides a virtual member function marked 'final', according to
/// C++11 [class.virtual]p4.
bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
                                            const CXXMethodDecl *Old);


//===--------------------------------------------------------------------===//
// C++ Access Control
//

enum AccessResult {
  AR_accessible,
  AR_inaccessible,
  AR_dependent,
  AR_delayed
};

bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
                              NamedDecl *PrevMemberDecl,
                              AccessSpecifier LexicalAS);

AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
                                   SourceRange PlacementRange,
                                   CXXRecordDecl *NamingClass,
                                   DeclAccessPair FoundDecl,
                                   bool Diagnose = true);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    bool IsCopyBindingRefToTemp = false);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    const PartialDiagnostic &PDiag);
AccessResult CheckDestructorAccess(SourceLocation Loc,
                                   CXXDestructorDecl *Dtor,
                                   const PartialDiagnostic &PDiag,
                                   QualType objectType = QualType());
AccessResult CheckFriendAccess(NamedDecl *D);
AccessResult CheckMemberAccess(SourceLocation UseLoc,
                               CXXRecordDecl *NamingClass,
                               DeclAccessPair Found);
AccessResult
CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
                                   CXXRecordDecl *DecomposedClass,
                                   DeclAccessPair Field);
AccessResult CheckMemberOperatorAccess(SourceLocation Loc,
                                       Expr *ObjectExpr,
                                       Expr *ArgExpr,
                                       DeclAccessPair FoundDecl);
AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
                                        DeclAccessPair FoundDecl);
AccessResult CheckBaseClassAccess(SourceLocation AccessLoc,
                                  QualType Base, QualType Derived,
                                  const CXXBasePath &Path,
                                  unsigned DiagID,
                                  bool ForceCheck = false,
                                  bool ForceUnprivileged = false);
void CheckLookupAccess(const LookupResult &R);
bool IsSimplyAccessible(NamedDecl *Decl, CXXRecordDecl *NamingClass,
                        QualType BaseType);
bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
                                   DeclAccessPair Found, QualType ObjectType,
                                   SourceLocation Loc,
                                   const PartialDiagnostic &Diag);
bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
                                   DeclAccessPair Found,
                                   QualType ObjectType) {
  return isMemberAccessibleForDeletion(NamingClass, Found, ObjectType,
                                       SourceLocation(), PDiag());
}

void HandleDependentAccessCheck(const DependentDiagnostic &DD,
                       const MultiLevelTemplateArgumentList &TemplateArgs);
void PerformDependentDiagnostics(const DeclContext *Pattern,
                      const MultiLevelTemplateArgumentList &TemplateArgs);

void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

/// When true, access checking violations are treated as SFINAE
/// failures rather than hard errors.
bool AccessCheckingSFINAE;

enum AbstractDiagSelID {
  AbstractNone = -1,
  AbstractReturnType,
  AbstractParamType,
  AbstractVariableType,
  AbstractFieldType,
  AbstractIvarType,
  AbstractSynthesizedIvarType,
  AbstractArrayType
};

bool isAbstractType(SourceLocation Loc, QualType T);
bool RequireNonAbstractType(SourceLocation Loc, QualType T,
                            TypeDiagnoser &Diagnoser);
template <typename... Ts>
bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
                            const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireNonAbstractType(Loc, T, Diagnoser);
}

void DiagnoseAbstractType(const CXXRecordDecl *RD);

//===--------------------------------------------------------------------===//
// C++ Overloaded Operators [C++ 13.5]
//

bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);

bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);

//===--------------------------------------------------------------------===//
// C++ Templates [C++ 14]
//
void FilterAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true);
bool hasAnyAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true,
                                   bool AllowNonTemplateFunctions = false);
/// Try to interpret the lookup result D as a template-name.
///
/// \param D A declaration found by name lookup.
/// \param AllowFunctionTemplates Whether function templates should be
///        considered valid results.
/// \param AllowDependent Whether unresolved using declarations (that might
///        name templates) should be considered valid results.
static NamedDecl *getAsTemplateNameDecl(NamedDecl *D,
                                        bool AllowFunctionTemplates = true,
                                        bool AllowDependent = true);

enum TemplateNameIsRequiredTag { TemplateNameIsRequired };
/// Whether and why a template name is required in this lookup.
class RequiredTemplateKind {
public:
  /// Template name is required if TemplateKWLoc is valid.
  RequiredTemplateKind(SourceLocation TemplateKWLoc = SourceLocation())
      : TemplateKW(TemplateKWLoc) {}
  /// Template name is unconditionally required.
  RequiredTemplateKind(TemplateNameIsRequiredTag) : TemplateKW() {}

  SourceLocation getTemplateKeywordLoc() const {
    return TemplateKW.getValueOr(SourceLocation());
  }
  bool hasTemplateKeyword() const { return getTemplateKeywordLoc().isValid(); }
  bool isRequired() const { return TemplateKW != SourceLocation(); }
  explicit operator bool() const { return isRequired(); }

private:
  llvm::Optional<SourceLocation> TemplateKW;
};

enum class AssumedTemplateKind {
  /// This is not assumed to be a template name.
  None,
  /// This is assumed to be a template name because lookup found nothing.
  FoundNothing,
  /// This is assumed to be a template name because lookup found one or more
  /// functions (but no function templates).
  FoundFunctions,
};
bool LookupTemplateName(
    LookupResult &R, Scope *S, CXXScopeSpec &SS, QualType ObjectType,
    bool EnteringContext, bool &MemberOfUnknownSpecialization,
    RequiredTemplateKind RequiredTemplate = SourceLocation(),
    AssumedTemplateKind *ATK = nullptr, bool AllowTypoCorrection = true);

TemplateNameKind isTemplateName(Scope *S,
                                CXXScopeSpec &SS,
                                bool hasTemplateKeyword,
                                const UnqualifiedId &Name,
                                ParsedType ObjectType,
                                bool EnteringContext,
                                TemplateTy &Template,
                                bool &MemberOfUnknownSpecialization,
                                bool Disambiguation = false);

/// Try to resolve an undeclared template name as a type template.
///
/// Sets II to the identifier corresponding to the template name, and updates
/// Name to a corresponding (typo-corrected) type template name and TNK to
/// the corresponding kind, if possible.
void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
                                     TemplateNameKind &TNK,
                                     SourceLocation NameLoc,
                                     IdentifierInfo *&II);

bool resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
                                      SourceLocation NameLoc,
                                      bool Diagnose = true);

/// Determine whether a particular identifier might be the name in a C++1z
/// deduction-guide declaration.
bool isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
                          SourceLocation NameLoc,
                          ParsedTemplateTy *Template = nullptr);

bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
                                 SourceLocation IILoc,
                                 Scope *S,
                                 const CXXScopeSpec *SS,
                                 TemplateTy &SuggestedTemplate,
                                 TemplateNameKind &SuggestedKind);

bool DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
                                    NamedDecl *Instantiation,
                                    bool InstantiatedFromMember,
                                    const NamedDecl *Pattern,
                                    const NamedDecl *PatternDef,
                                    TemplateSpecializationKind TSK,
                                    bool Complain = true);

void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl);
TemplateDecl *AdjustDeclIfTemplate(Decl *&Decl);

NamedDecl *ActOnTypeParameter(Scope *S, bool Typename,
                              SourceLocation EllipsisLoc,
                              SourceLocation KeyLoc,
                              IdentifierInfo *ParamName,
                              SourceLocation ParamNameLoc,
                              unsigned Depth, unsigned Position,
                              SourceLocation EqualLoc,
                              ParsedType DefaultArg, bool HasTypeConstraint);

bool ActOnTypeConstraint(const CXXScopeSpec &SS,
                         TemplateIdAnnotation *TypeConstraint,
                         TemplateTypeParmDecl *ConstrainedParameter,
                         SourceLocation EllipsisLoc);
bool BuildTypeConstraint(const CXXScopeSpec &SS,
                         TemplateIdAnnotation *TypeConstraint,
                         TemplateTypeParmDecl *ConstrainedParameter,
                         SourceLocation EllipsisLoc,
                         bool AllowUnexpandedPack);

bool AttachTypeConstraint(NestedNameSpecifierLoc NS,
                          DeclarationNameInfo NameInfo,
                          ConceptDecl *NamedConcept,
                          const TemplateArgumentListInfo *TemplateArgs,
                          TemplateTypeParmDecl *ConstrainedParameter,
                          SourceLocation EllipsisLoc);

bool AttachTypeConstraint(AutoTypeLoc TL,
                          NonTypeTemplateParmDecl *ConstrainedParameter,
                          SourceLocation EllipsisLoc);

bool RequireStructuralType(QualType T, SourceLocation Loc);

QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
                                           SourceLocation Loc);
QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);

NamedDecl *ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
                                    unsigned Depth,
                                    unsigned Position,
                                    SourceLocation EqualLoc,
                                    Expr *DefaultArg);
NamedDecl *ActOnTemplateTemplateParameter(Scope *S,
                                     SourceLocation TmpLoc,
                                     TemplateParameterList *Params,
                                     SourceLocation EllipsisLoc,
                                     IdentifierInfo *ParamName,
                                     SourceLocation ParamNameLoc,
                                     unsigned Depth,
                                     unsigned Position,
                                     SourceLocation EqualLoc,
                                     ParsedTemplateArgument DefaultArg);

TemplateParameterList *
ActOnTemplateParameterList(unsigned Depth,
                           SourceLocation ExportLoc,
                           SourceLocation TemplateLoc,
                           SourceLocation LAngleLoc,
                           ArrayRef<NamedDecl *> Params,
                           SourceLocation RAngleLoc,
                           Expr *RequiresClause);

/// The context in which we are checking a template parameter list.
enum TemplateParamListContext {
  TPC_ClassTemplate,
  TPC_VarTemplate,
  TPC_FunctionTemplate,
  TPC_ClassTemplateMember,
  TPC_FriendClassTemplate,
  TPC_FriendFunctionTemplate,
  TPC_FriendFunctionTemplateDefinition,
  TPC_TypeAliasTemplate
};

bool CheckTemplateParameterList(TemplateParameterList *NewParams,
                                TemplateParameterList *OldParams,
                                TemplateParamListContext TPC,
                                SkipBodyInfo *SkipBody = nullptr);
TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
    SourceLocation DeclStartLoc, SourceLocation DeclLoc,
    const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
    ArrayRef<TemplateParameterList *> ParamLists,
    bool IsFriend, bool &IsMemberSpecialization, bool &Invalid,
    bool SuppressDiagnostic = false);

DeclResult CheckClassTemplate(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
    const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
    AccessSpecifier AS, SourceLocation ModulePrivateLoc,
    SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
    TemplateParameterList **OuterTemplateParamLists,
    SkipBodyInfo *SkipBody = nullptr);

TemplateArgumentLoc getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
                                                  QualType NTTPType,
                                                  SourceLocation Loc);

/// Get a template argument mapping the given template parameter to itself,
/// e.g. for X in \c template<int X>, this would return an expression template
/// argument referencing X.
TemplateArgumentLoc getIdentityTemplateArgumentLoc(NamedDecl *Param,
                                                   SourceLocation Location);

void translateTemplateArguments(const ASTTemplateArgsPtr &In,
                                TemplateArgumentListInfo &Out);

ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);

void NoteAllFoundTemplates(TemplateName Name);

QualType CheckTemplateIdType(TemplateName Template,
                             SourceLocation TemplateLoc,
                            TemplateArgumentListInfo &TemplateArgs);

TypeResult
ActOnTemplateIdType(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
                    TemplateTy Template, IdentifierInfo *TemplateII,
                    SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                    ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
                    bool IsCtorOrDtorName = false, bool IsClassName = false);

/// Parsed an elaborated-type-specifier that refers to a template-id,
/// such as \c class T::template apply<U>.
TypeResult ActOnTagTemplateIdType(TagUseKind TUK,
                                  TypeSpecifierType TagSpec,
                                  SourceLocation TagLoc,
                                  CXXScopeSpec &SS,
                                  SourceLocation TemplateKWLoc,
                                  TemplateTy TemplateD,
                                  SourceLocation TemplateLoc,
                                  SourceLocation LAngleLoc,
                                  ASTTemplateArgsPtr TemplateArgsIn,
                                  SourceLocation RAngleLoc);

DeclResult ActOnVarTemplateSpecialization(
    Scope *S, Declarator &D, TypeSourceInfo *DI,
    SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
    StorageClass SC, bool IsPartialSpecialization);

/// Get the specialization of the given variable template corresponding to
/// the specified argument list, or a null-but-valid result if the arguments
/// are dependent.
DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              SourceLocation TemplateNameLoc,
                              const TemplateArgumentListInfo &TemplateArgs);

/// Form a reference to the specialization of the given variable template
/// corresponding to the specified argument list, or a null-but-valid result
/// if the arguments are dependent.
ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
                              const DeclarationNameInfo &NameInfo,
                              VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult
CheckConceptTemplateId(const CXXScopeSpec &SS,
                       SourceLocation TemplateKWLoc,
                       const DeclarationNameInfo &ConceptNameInfo,
                       NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
                       const TemplateArgumentListInfo *TemplateArgs);

void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);

ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
                               SourceLocation TemplateKWLoc,
                               LookupResult &R,
                               bool RequiresADL,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
                                        SourceLocation TemplateKWLoc,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

TemplateNameKind ActOnTemplateName(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    const UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext,
    TemplateTy &Template, bool AllowInjectedClassName = false);

DeclResult ActOnClassTemplateSpecialization(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
    TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
    MultiTemplateParamsArg TemplateParameterLists,
    SkipBodyInfo *SkipBody = nullptr);

bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
                                            TemplateDecl *PrimaryTemplate,
                                            unsigned NumExplicitArgs,
                                            ArrayRef<TemplateArgument> Args);
void CheckTemplatePartialSpecialization(
    ClassTemplatePartialSpecializationDecl *Partial);
void CheckTemplatePartialSpecialization(
    VarTemplatePartialSpecializationDecl *Partial);

Decl *ActOnTemplateDeclarator(Scope *S,
                              MultiTemplateParamsArg TemplateParameterLists,
                              Declarator &D);

bool
CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
                                       TemplateSpecializationKind NewTSK,
                                       NamedDecl *PrevDecl,
                                       TemplateSpecializationKind PrevTSK,
                                       SourceLocation PrevPtOfInstantiation,
                                       bool &SuppressNew);

bool CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
                  const TemplateArgumentListInfo &ExplicitTemplateArgs,
                                                  LookupResult &Previous);

bool CheckFunctionTemplateSpecialization(
    FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
    LookupResult &Previous, bool QualifiedFriend = false);
bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);

DeclResult ActOnExplicitInstantiation(
    Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
    unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
    TemplateTy Template, SourceLocation TemplateNameLoc,
    SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
    SourceLocation RAngleLoc, const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      unsigned TagSpec, SourceLocation KWLoc,
                                      CXXScopeSpec &SS, IdentifierInfo *Name,
                                      SourceLocation NameLoc,
                                      const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S,
                                      SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      Declarator &D);

TemplateArgumentLoc
SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
                                        SourceLocation TemplateLoc,
                                        SourceLocation RAngleLoc,
                                        Decl *Param,
                                        SmallVectorImpl<TemplateArgument>
                                          &Converted,
                                        bool &HasDefaultArg);

/// Specifies the context in which a particular template
/// argument is being checked.
enum CheckTemplateArgumentKind {
  /// The template argument was specified in the code or was
  /// instantiated with some deduced template arguments.
  CTAK_Specified,

  /// The template argument was deduced via template argument
  /// deduction.
  CTAK_Deduced,

  /// The template argument was deduced from an array bound
  /// via template argument deduction.
  CTAK_DeducedFromArrayBound
};

bool CheckTemplateArgument(NamedDecl *Param,
                           TemplateArgumentLoc &Arg,
                           NamedDecl *Template,
                           SourceLocation TemplateLoc,
                           SourceLocation RAngleLoc,
                           unsigned ArgumentPackIndex,
                         SmallVectorImpl<TemplateArgument> &Converted,
                           CheckTemplateArgumentKind CTAK = CTAK_Specified);

/// Check that the given template arguments can be be provided to
/// the given template, converting the arguments along the way.
///
/// \param Template The template to which the template arguments are being
/// provided.
///
/// \param TemplateLoc The location of the template name in the source.
///
/// \param TemplateArgs The list of template arguments. If the template is
/// a template template parameter, this function may extend the set of
/// template arguments to also include substituted, defaulted template
/// arguments.
///
/// \param PartialTemplateArgs True if the list of template arguments is
/// intentionally partial, e.g., because we're checking just the initial
/// set of template arguments.
///
/// \param Converted Will receive the converted, canonicalized template
/// arguments.
///
/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
/// contain the converted forms of the template arguments as written.
/// Otherwise, \p TemplateArgs will not be modified.
///
/// \param ConstraintsNotSatisfied If provided, and an error occured, will
/// receive true if the cause for the error is the associated constraints of
/// the template not being satisfied by the template arguments.
///
/// \returns true if an error occurred, false otherwise.
bool CheckTemplateArgumentList(TemplateDecl *Template,
                               SourceLocation TemplateLoc,
                               TemplateArgumentListInfo &TemplateArgs,
                               bool PartialTemplateArgs,
                               SmallVectorImpl<TemplateArgument> &Converted,
                               bool UpdateArgsWithConversions = true,
                               bool *ConstraintsNotSatisfied = nullptr);

bool CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
                               TemplateArgumentLoc &Arg,
                         SmallVectorImpl<TemplateArgument> &Converted);

bool CheckTemplateArgument(TypeSourceInfo *Arg);
ExprResult CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
                                 QualType InstantiatedParamType, Expr *Arg,
                                 TemplateArgument &Converted,
                             CheckTemplateArgumentKind CTAK = CTAK_Specified);
bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
                                   TemplateParameterList *Params,
                                   TemplateArgumentLoc &Arg);

ExprResult
BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
                                        QualType ParamType,
                                        SourceLocation Loc);
ExprResult
BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
                                            SourceLocation Loc);

/// Enumeration describing how template parameter lists are compared
/// for equality.
enum TemplateParameterListEqualKind {
  /// We are matching the template parameter lists of two templates
  /// that might be redeclarations.
  ///
  /// \code
  /// template<typename T> struct X;
  /// template<typename T> struct X;
  /// \endcode
  TPL_TemplateMatch,

  /// We are matching the template parameter lists of two template
  /// template parameters as part of matching the template parameter lists
  /// of two templates that might be redeclarations.
  ///
  /// \code
  /// template<template<int I> class TT> struct X;
  /// template<template<int Value> class Other> struct X;
  /// \endcode
  TPL_TemplateTemplateParmMatch,

  /// We are matching the template parameter lists of a template
  /// template argument against the template parameter lists of a template
  /// template parameter.
  ///
  /// \code
  /// template<template<int Value> class Metafun> struct X;
  /// template<int Value> struct integer_c;
  /// X<integer_c> xic;
  /// \endcode
  TPL_TemplateTemplateArgumentMatch
};

bool TemplateParameterListsAreEqual(TemplateParameterList *New,
                                    TemplateParameterList *Old,
                                    bool Complain,
                                    TemplateParameterListEqualKind Kind,
                                    SourceLocation TemplateArgLoc
                                      = SourceLocation());

bool CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams);

/// Called when the parser has parsed a C++ typename
/// specifier, e.g., "typename T::type".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param II the identifier we're retrieving (e.g., 'type' in the example).
/// \param IdLoc the location of the identifier.
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS, const IdentifierInfo &II,
                  SourceLocation IdLoc);

/// Called when the parser has parsed a C++ typename
/// specifier that ends in a template-id, e.g.,
/// "typename MetaFun::template apply<T1, T2>".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param TemplateLoc the location of the 'template' keyword, if any.
/// \param TemplateName The template name.
/// \param TemplateII The identifier used to name the template.
/// \param TemplateIILoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS,
                  SourceLocation TemplateLoc,
                  TemplateTy TemplateName,
                  IdentifierInfo *TemplateII,
                  SourceLocation TemplateIILoc,
                  SourceLocation LAngleLoc,
                  ASTTemplateArgsPtr TemplateArgs,
                  SourceLocation RAngleLoc);

QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
                           SourceLocation KeywordLoc,
                           NestedNameSpecifierLoc QualifierLoc,
                           const IdentifierInfo &II,
                           SourceLocation IILoc,
                           TypeSourceInfo **TSI,
                           bool DeducedTSTContext);

QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
                           SourceLocation KeywordLoc,
                           NestedNameSpecifierLoc QualifierLoc,
                           const IdentifierInfo &II,
                           SourceLocation IILoc,
                           bool DeducedTSTContext = true);


TypeSourceInfo *RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
                                                  SourceLocation Loc,
                                                  DeclarationName Name);
bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);

ExprResult RebuildExprInCurrentInstantiation(Expr *E);
bool RebuildTemplateParamsInCurrentInstantiation(
                                              TemplateParameterList *Params);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgumentList &Args);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgument *Args,
                                unsigned NumArgs);

//===--------------------------------------------------------------------===//
// C++ Concepts
//===--------------------------------------------------------------------===//
Decl *ActOnConceptDefinition(
    Scope *S, MultiTemplateParamsArg TemplateParameterLists,
    IdentifierInfo *Name, SourceLocation NameLoc, Expr *ConstraintExpr);

RequiresExprBodyDecl *
ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
                       ArrayRef<ParmVarDecl *> LocalParameters,
                       Scope *BodyScope);
void ActOnFinishRequiresExpr();
concepts::Requirement *ActOnSimpleRequirement(Expr *E);
concepts::Requirement *ActOnTypeRequirement(
    SourceLocation TypenameKWLoc, CXXScopeSpec &SS, SourceLocation NameLoc,
    IdentifierInfo *TypeName, TemplateIdAnnotation *TemplateId);
concepts::Requirement *ActOnCompoundRequirement(Expr *E,
                                                SourceLocation NoexceptLoc);
concepts::Requirement *
ActOnCompoundRequirement(
    Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
    TemplateIdAnnotation *TypeConstraint, unsigned Depth);
concepts::Requirement *ActOnNestedRequirement(Expr *Constraint);
concepts::ExprRequirement *
BuildExprRequirement(
    Expr *E, bool IsSatisfied, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
concepts::ExprRequirement *
BuildExprRequirement(
    concepts::Requirement::SubstitutionDiagnostic *ExprSubstDiag,
    bool IsSatisfied, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
concepts::TypeRequirement *BuildTypeRequirement(TypeSourceInfo *Type);
concepts::TypeRequirement *
BuildTypeRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
concepts::NestedRequirement *BuildNestedRequirement(Expr *E);
concepts::NestedRequirement *
BuildNestedRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
                             RequiresExprBodyDecl *Body,
                             ArrayRef<ParmVarDecl *> LocalParameters,
                             ArrayRef<concepts::Requirement *> Requirements,
                             SourceLocation ClosingBraceLoc);

//===--------------------------------------------------------------------===//
// C++ Variadic Templates (C++0x [temp.variadic])
//===--------------------------------------------------------------------===//

/// Determine whether an unexpanded parameter pack might be permitted in this
/// location. Useful for error recovery.
bool isUnexpandedParameterPackPermitted();

/// The context in which an unexpanded parameter pack is
/// being diagnosed.
///
/// Note that the values of this enumeration line up with the first
/// argument to the \c err_unexpanded_parameter_pack diagnostic.
enum UnexpandedParameterPackContext {
  /// An arbitrary expression.
  UPPC_Expression = 0,

  /// The base type of a class type.
  UPPC_BaseType,

  /// The type of an arbitrary declaration.
  UPPC_DeclarationType,

  /// The type of a data member.
  UPPC_DataMemberType,

  /// The size of a bit-field.
  UPPC_BitFieldWidth,

  /// The expression in a static assertion.
  UPPC_StaticAssertExpression,

  /// The fixed underlying type of an enumeration.
  UPPC_FixedUnderlyingType,

  /// The enumerator value.
  UPPC_EnumeratorValue,

  /// A using declaration.
  UPPC_UsingDeclaration,

  /// A friend declaration.
  UPPC_FriendDeclaration,

  /// A declaration qualifier.
  UPPC_DeclarationQualifier,

  /// An initializer.
  UPPC_Initializer,

  /// A default argument.
  UPPC_DefaultArgument,

  /// The type of a non-type template parameter.
  UPPC_NonTypeTemplateParameterType,

  /// The type of an exception.
  UPPC_ExceptionType,

  /// Partial specialization.
  UPPC_PartialSpecialization,

  /// Microsoft __if_exists.
  UPPC_IfExists,

  /// Microsoft __if_not_exists.
  UPPC_IfNotExists,

  /// Lambda expression.
  UPPC_Lambda,

  /// Block expression.
  UPPC_Block,

  /// A type constraint.
  UPPC_TypeConstraint,

  // A requirement in a requires-expression.
  UPPC_Requirement,

  // A requires-clause.
  UPPC_RequiresClause,
};

/// Diagnose unexpanded parameter packs.
///
/// \param Loc The location at which we should emit the diagnostic.
///
/// \param UPPC The context in which we are diagnosing unexpanded
/// parameter packs.
///
/// \param Unexpanded the set of unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
                                      UnexpandedParameterPackContext UPPC,
                                ArrayRef<UnexpandedParameterPack> Unexpanded);

/// If the given type contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The source location where a diagnostc should be emitted.
///
/// \param T The type that is being checked for unexpanded parameter
/// packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
                                     UnexpandedParameterPackContext UPPC);

/// If the given expression contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param E The expression that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(Expr *E,
                     UnexpandedParameterPackContext UPPC = UPPC_Expression);

/// If the given requirees-expression contains an unexpanded reference to one
/// of its own parameter packs, diagnose the error.
///
/// \param RE The requiress-expression that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPackInRequiresExpr(RequiresExpr *RE);

/// If the given nested-name-specifier contains an unexpanded
/// parameter pack, diagnose the error.
///
/// \param SS The nested-name-specifier that is being checked for
/// unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
                                     UnexpandedParameterPackContext UPPC);

/// If the given name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param NameInfo The name (with source location information) that
/// is being checked for unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The location of the template name.
///
/// \param Template The template name that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
                                     TemplateName Template,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template argument contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param Arg The template argument that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
                                     UnexpandedParameterPackContext UPPC);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgument Arg,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgumentLoc Arg,
                  SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param T The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(QualType T,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param TL The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TypeLoc TL,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// nested-name-specifier.
///
/// \param NNS The nested-name-specifier that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(NestedNameSpecifierLoc NNS,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// name.
///
/// \param NameInfo The name that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(const DeclarationNameInfo &NameInfo,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Invoked when parsing a template argument followed by an
/// ellipsis, which creates a pack expansion.
///
/// \param Arg The template argument preceding the ellipsis, which
/// may already be invalid.
///
/// \param EllipsisLoc The location of the ellipsis.
ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
                                          SourceLocation EllipsisLoc);

/// Invoked when parsing a type followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Type The type preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
TypeSourceInfo *CheckPackExpansion(TypeSourceInfo *Pattern,
                                   SourceLocation EllipsisLoc,
                                   Optional<unsigned> NumExpansions);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
QualType CheckPackExpansion(QualType Pattern,
                            SourceRange PatternRange,
                            SourceLocation EllipsisLoc,
                            Optional<unsigned> NumExpansions);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
                              Optional<unsigned> NumExpansions);

/// Determine whether we could expand a pack expansion with the
/// given set of parameter packs into separate arguments by repeatedly
/// transforming the pattern.
///
/// \param EllipsisLoc The location of the ellipsis that identifies the
/// pack expansion.
///
/// \param PatternRange The source range that covers the entire pattern of
/// the pack expansion.
///
/// \param Unexpanded The set of unexpanded parameter packs within the
/// pattern.
///
/// \param ShouldExpand Will be set to \c true if the transformer should
/// expand the corresponding pack expansions into separate arguments. When
/// set, \c NumExpansions must also be set.
///
/// \param RetainExpansion Whether the caller should add an unexpanded
/// pack expansion after all of the expanded arguments. This is used
/// when extending explicitly-specified template argument packs per
/// C++0x [temp.arg.explicit]p9.
///
/// \param NumExpansions The number of separate arguments that will be in
/// the expanded form of the corresponding pack expansion. This is both an
/// input and an output parameter, which can be set by the caller if the
/// number of expansions is known a priori (e.g., due to a prior substitution)
/// and will be set by the callee when the number of expansions is known.
/// The callee must set this value when \c ShouldExpand is \c true; it may
/// set this value in other cases.
///
/// \returns true if an error occurred (e.g., because the parameter packs
/// are to be instantiated with arguments of different lengths), false
/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
/// must be set.
bool CheckParameterPacksForExpansion(SourceLocation EllipsisLoc,
                                     SourceRange PatternRange,
                           ArrayRef<UnexpandedParameterPack> Unexpanded,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                                     bool &ShouldExpand,
                                     bool &RetainExpansion,
                                     Optional<unsigned> &NumExpansions);

/// Determine the number of arguments in the given pack expansion
/// type.
///
/// This routine assumes that the number of arguments in the expansion is
/// consistent across all of the unexpanded parameter packs in its pattern.
///
/// Returns an empty Optional if the type can't be expanded.
Optional<unsigned> getNumArgumentsInExpansion(QualType T,
    const MultiLevelTemplateArgumentList &TemplateArgs);

/// Determine whether the given declarator contains any unexpanded
/// parameter packs.
///
/// This routine is used by the parser to disambiguate function declarators
/// with an ellipsis prior to the ')', e.g.,
///
/// \code
///   void f(T...);
/// \endcode
///
/// To determine whether we have an (unnamed) function parameter pack or
/// a variadic function.
///
/// \returns true if the declarator contains any unexpanded parameter packs,
/// false otherwise.
bool containsUnexpandedParameterPacks(Declarator &D);

/// Returns the pattern of the pack expansion for a template argument.
///
/// \param OrigLoc The template argument to expand.
///
/// \param Ellipsis Will be set to the location of the ellipsis.
///
/// \param NumExpansions Will be set to the number of expansions that will
/// be generated from this pack expansion, if known a priori.
TemplateArgumentLoc getTemplateArgumentPackExpansionPattern(
    TemplateArgumentLoc OrigLoc,
    SourceLocation &Ellipsis,
    Optional<unsigned> &NumExpansions) const;

/// Given a template argument that contains an unexpanded parameter pack, but
/// which has already been substituted, attempt to determine the number of
/// elements that will be produced once this argument is fully-expanded.
///
/// This is intended for use when transforming 'sizeof...(Arg)' in order to
/// avoid actually expanding the pack where possible.
Optional<unsigned> getFullyPackExpandedSize(TemplateArgument Arg);

//===--------------------------------------------------------------------===//
// C++ Template Argument Deduction (C++ [temp.deduct])
//===--------------------------------------------------------------------===//

/// Adjust the type \p ArgFunctionType to match the calling convention,
/// noreturn, and optionally the exception specification of \p FunctionType.
/// Deduction often wants to ignore these properties when matching function
/// types.
QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
                             bool AdjustExceptionSpec = false);

/// Describes the result of template argument deduction.
///
/// The TemplateDeductionResult enumeration describes the result of
/// template argument deduction, as returned from
/// DeduceTemplateArguments(). The separate TemplateDeductionInfo
/// structure provides additional information about the results of
/// template argument deduction, e.g., the deduced template argument
/// list (if successful) or the specific template parameters or
/// deduced arguments that were involved in the failure.
enum TemplateDeductionResult {
  /// Template argument deduction was successful.
  TDK_Success = 0,
  /// The declaration was invalid; do nothing.
  TDK_Invalid,
  /// Template argument deduction exceeded the maximum template
  /// instantiation depth (which has already been diagnosed).
  TDK_InstantiationDepth,
  /// Template argument deduction did not deduce a value
  /// for every template parameter.
  TDK_Incomplete,
  /// Template argument deduction did not deduce a value for every
  /// expansion of an expanded template parameter pack.
  TDK_IncompletePack,
  /// Template argument deduction produced inconsistent
  /// deduced values for the given template parameter.
  TDK_Inconsistent,
  /// Template argument deduction failed due to inconsistent
  /// cv-qualifiers on a template parameter type that would
  /// otherwise be deduced, e.g., we tried to deduce T in "const T"
  /// but were given a non-const "X".
  TDK_Underqualified,
  /// Substitution of the deduced template argument values
  /// resulted in an error.
  TDK_SubstitutionFailure,
  /// After substituting deduced template arguments, a dependent
  /// parameter type did not match the corresponding argument.
  TDK_DeducedMismatch,
  /// After substituting deduced template arguments, an element of
  /// a dependent parameter type did not match the corresponding element
  /// of the corresponding argument (when deducing from an initializer list).
  TDK_DeducedMismatchNested,
  /// A non-depnedent component of the parameter did not match the
  /// corresponding component of the argument.
  TDK_NonDeducedMismatch,
  /// When performing template argument deduction for a function
  /// template, there were too many call arguments.
  TDK_TooManyArguments,
  /// When performing template argument deduction for a function
  /// template, there were too few call arguments.
  TDK_TooFewArguments,
  /// The explicitly-specified template arguments were not valid
  /// template arguments for the given template.
  TDK_InvalidExplicitArguments,
  /// Checking non-dependent argument conversions failed.
  TDK_NonDependentConversionFailure,
  /// The deduced arguments did not satisfy the constraints associated
  /// with the template.
  TDK_ConstraintsNotSatisfied,
  /// Deduction failed; that's all we know.
  TDK_MiscellaneousDeductionFailure,
  /// CUDA Target attributes do not match.
  TDK_CUDATargetMismatch
};

TemplateDeductionResult
DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult SubstituteExplicitTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo &ExplicitTemplateArgs,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
    sema::TemplateDeductionInfo &Info);

/// brief A function argument from which we performed template argument
// deduction for a call.
struct OriginalCallArg {
  OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
                  unsigned ArgIdx, QualType OriginalArgType)
      : OriginalParamType(OriginalParamType),
        DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
        OriginalArgType(OriginalArgType) {}

  QualType OriginalParamType;
  bool DecomposedParam;
  unsigned ArgIdx;
  QualType OriginalArgType;
};

TemplateDeductionResult FinishTemplateArgumentDeduction(
    FunctionTemplateDecl *FunctionTemplate,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
    sema::TemplateDeductionInfo &Info,
    SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs = nullptr,
    bool PartialOverloading = false,
    llvm::function_ref<bool()> CheckNonDependent = []{ return false; });

TemplateDeductionResult DeduceTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
    bool PartialOverloading,
    llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        QualType ArgFunctionType,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        QualType ToType,
                        CXXConversionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

/// Substitute Replacement for \p auto in \p TypeWithAuto
QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
/// Substitute Replacement for auto in TypeWithAuto
TypeSourceInfo* SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                        QualType Replacement);
/// Completely replace the \c auto in \p TypeWithAuto by
/// \p Replacement. This does not retain any \c auto type sugar.
QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);
TypeSourceInfo *ReplaceAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                          QualType Replacement);

/// Result type of DeduceAutoType.
enum DeduceAutoResult {
  DAR_Succeeded,
  DAR_Failed,
  DAR_FailedAlreadyDiagnosed
};

DeduceAutoResult
DeduceAutoType(TypeSourceInfo *AutoType, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None,
               bool IgnoreConstraints = false);
DeduceAutoResult
DeduceAutoType(TypeLoc AutoTypeLoc, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None,
               bool IgnoreConstraints = false);
void DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init);
bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
                      bool Diagnose = true);

/// Declare implicit deduction guides for a class template if we've
/// not already done so.
void DeclareImplicitDeductionGuides(TemplateDecl *Template,
                                    SourceLocation Loc);

QualType DeduceTemplateSpecializationFromInitializer(
    TypeSourceInfo *TInfo, const InitializedEntity &Entity,
    const InitializationKind &Kind, MultiExprArg Init);

QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
                                      QualType Type, TypeSourceInfo *TSI,
                                      SourceRange Range, bool DirectInit,
                                      Expr *Init);

TypeLoc getReturnTypeLoc(FunctionDecl *FD) const;

bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
                                      SourceLocation ReturnLoc,
                                      Expr *&RetExpr, AutoType *AT);

FunctionTemplateDecl *getMoreSpecializedTemplate(
    FunctionTemplateDecl *FT1, FunctionTemplateDecl *FT2, SourceLocation Loc,
    TemplatePartialOrderingContext TPOC, unsigned NumCallArguments1,
    unsigned NumCallArguments2, bool Reversed = false);
UnresolvedSetIterator
getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
                   TemplateSpecCandidateSet &FailedCandidates,
                   SourceLocation Loc,
                   const PartialDiagnostic &NoneDiag,
                   const PartialDiagnostic &AmbigDiag,
                   const PartialDiagnostic &CandidateDiag,
                   bool Complain = true, QualType TargetType = QualType());

ClassTemplatePartialSpecializationDecl *
getMoreSpecializedPartialSpecialization(
                                ClassTemplatePartialSpecializationDecl *PS1,
                                ClassTemplatePartialSpecializationDecl *PS2,
                                SourceLocation Loc);

bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
    VarTemplatePartialSpecializationDecl *PS1,
    VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);

bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
    TemplateParameterList *PParam, TemplateDecl *AArg, SourceLocation Loc);

void MarkUsedTemplateParameters(const Expr *E, bool OnlyDeduced,
                                unsigned Depth, llvm::SmallBitVector &Used);

void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
                                bool OnlyDeduced,
                                unsigned Depth,
                                llvm::SmallBitVector &Used);
void MarkDeducedTemplateParameters(
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced) {
  return MarkDeducedTemplateParameters(Context, FunctionTemplate, Deduced);
}
static void MarkDeducedTemplateParameters(ASTContext &Ctx,
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced);

//===--------------------------------------------------------------------===//
// C++ Template Instantiation
//

MultiLevelTemplateArgumentList
getTemplateInstantiationArgs(NamedDecl *D,
                             const TemplateArgumentList *Innermost = nullptr,
                             bool RelativeToPrimary = false,
                             const FunctionDecl *Pattern = nullptr);

/// A context in which code is being synthesized (where a source location
/// alone is not sufficient to identify the context). This covers template
/// instantiation and various forms of implicitly-generated functions.
struct CodeSynthesisContext {
  /// The kind of template instantiation we are performing
  enum SynthesisKind {
    /// We are instantiating a template declaration. The entity is
    /// the declaration we're instantiating (e.g., a CXXRecordDecl).
    TemplateInstantiation,

    /// We are instantiating a default argument for a template
    /// parameter. The Entity is the template parameter whose argument is
    /// being instantiated, the Template is the template, and the
    /// TemplateArgs/NumTemplateArguments provide the template arguments as
    /// specified.
    DefaultTemplateArgumentInstantiation,

    /// We are instantiating a default argument for a function.
    /// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
    /// provides the template arguments as specified.
    DefaultFunctionArgumentInstantiation,

    /// We are substituting explicit template arguments provided for
    /// a function template. The entity is a FunctionTemplateDecl.
    ExplicitTemplateArgumentSubstitution,

    /// We are substituting template argument determined as part of
    /// template argument deduction for either a class template
    /// partial specialization or a function template. The
    /// Entity is either a {Class|Var}TemplatePartialSpecializationDecl or
    /// a TemplateDecl.
    DeducedTemplateArgumentSubstitution,

    /// We are substituting prior template arguments into a new
    /// template parameter. The template parameter itself is either a
    /// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
    PriorTemplateArgumentSubstitution,

    /// We are checking the validity of a default template argument that
    /// has been used when naming a template-id.
    DefaultTemplateArgumentChecking,

    /// We are computing the exception specification for a defaulted special
    /// member function.
    ExceptionSpecEvaluation,

    /// We are instantiating the exception specification for a function
    /// template which was deferred until it was needed.
    ExceptionSpecInstantiation,

    /// We are instantiating a requirement of a requires expression.
    RequirementInstantiation,

    /// We are checking the satisfaction of a nested requirement of a requires
    /// expression.
    NestedRequirementConstraintsCheck,

    /// We are declaring an implicit special member function.
    DeclaringSpecialMember,

    /// We are declaring an implicit 'operator==' for a defaulted
    /// 'operator<=>'.
    DeclaringImplicitEqualityComparison,

    /// We are defining a synthesized function (such as a defaulted special
    /// member).
    DefiningSynthesizedFunction,

    // We are checking the constraints associated with a constrained entity or
    // the constraint expression of a concept. This includes the checks that
    // atomic constraints have the type 'bool' and that they can be constant
    // evaluated.
    ConstraintsCheck,

    // We are substituting template arguments into a constraint expression.
    ConstraintSubstitution,

    // We are normalizing a constraint expression.
    ConstraintNormalization,

    // We are substituting into the parameter mapping of an atomic constraint
    // during normalization.
    ParameterMappingSubstitution,

    /// We are rewriting a comparison operator in terms of an operator<=>.
    RewritingOperatorAsSpaceship,

    /// We are initializing a structured binding.
    InitializingStructuredBinding,

    /// We are marking a class as __dllexport.
    MarkingClassDllexported,

    /// Added for Template instantiation observation.
    /// Memoization means we are _not_ instantiating a template because
    /// it is already instantiated (but we entered a context where we
    /// would have had to if it was not already instantiated).
    Memoization
  } Kind;

  /// Was the enclosing context a non-instantiation SFINAE context?
  bool SavedInNonInstantiationSFINAEContext;

  /// The point of instantiation or synthesis within the source code.
  SourceLocation PointOfInstantiation;

  /// The entity that is being synthesized.
  Decl *Entity;

  /// The template (or partial specialization) in which we are
  /// performing the instantiation, for substitutions of prior template
  /// arguments.
  NamedDecl *Template;

  /// The list of template arguments we are substituting, if they
  /// are not part of the entity.
  const TemplateArgument *TemplateArgs;

  // FIXME: Wrap this union around more members, or perhaps store the
  // kind-specific members in the RAII object owning the context.
  union {
    /// The number of template arguments in TemplateArgs.
    unsigned NumTemplateArgs;

    /// The special member being declared or defined.
    CXXSpecialMember SpecialMember;
  };

  ArrayRef<TemplateArgument> template_arguments() const {
    assert(Kind != DeclaringSpecialMember)((void)0);
    return {TemplateArgs, NumTemplateArgs};
  }

  /// The template deduction info object associated with the
  /// substitution or checking of explicit or deduced template arguments.
  sema::TemplateDeductionInfo *DeductionInfo;

  /// The source range that covers the construct that cause
  /// the instantiation, e.g., the template-id that causes a class
  /// template instantiation.
  SourceRange InstantiationRange;

  CodeSynthesisContext()
      : Kind(TemplateInstantiation),
        SavedInNonInstantiationSFINAEContext(false), Entity(nullptr),
        Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(0),
        DeductionInfo(nullptr) {}

  /// Determines whether this template is an actual instantiation
  /// that should be counted toward the maximum instantiation depth.
  bool isInstantiationRecord() const;
};

/// List of active code synthesis contexts.
///
/// This vector is treated as a stack. As synthesis of one entity requires
/// synthesis of another, additional contexts are pushed onto the stack.
SmallVector<CodeSynthesisContext, 16> CodeSynthesisContexts;

/// Specializations whose definitions are currently being instantiated.
llvm::DenseSet<std::pair<Decl *, unsigned>> InstantiatingSpecializations;

/// Non-dependent types used in templates that have already been instantiated
/// by some template instantiation.
llvm::DenseSet<QualType> InstantiatedNonDependentTypes;

/// Extra modules inspected when performing a lookup during a template
/// instantiation. Computed lazily.
SmallVector<Module*, 16> CodeSynthesisContextLookupModules;

/// Cache of additional modules that should be used for name lookup
/// within the current template instantiation. Computed lazily; use
/// getLookupModules() to get a complete set.
llvm::DenseSet<Module*> LookupModulesCache;

/// Get the set of additional modules that should be checked during
/// name lookup. A module and its imports become visible when instanting a
/// template defined within it.
llvm::DenseSet<Module*> &getLookupModules();

/// Map from the most recent declaration of a namespace to the most
/// recent visible declaration of that namespace.
llvm::DenseMap<NamedDecl*, NamedDecl*> VisibleNamespaceCache;

/// Whether we are in a SFINAE context that is not associated with
/// template instantiation.
///
/// This is used when setting up a SFINAE trap (\c see SFINAETrap) outside
/// of a template instantiation or template argument deduction.
bool InNonInstantiationSFINAEContext;

/// The number of \p CodeSynthesisContexts that are not template
/// instantiations and, therefore, should not be counted as part of the
/// instantiation depth.
///
/// When the instantiation depth reaches the user-configurable limit
/// \p LangOptions::InstantiationDepth we will abort instantiation.
// FIXME: Should we have a similar limit for other forms of synthesis?
unsigned NonInstantiationEntries;

/// The depth of the context stack at the point when the most recent
/// error or warning was produced.
///
/// This value is used to suppress printing of redundant context stacks
/// when there are multiple errors or warnings in the same instantiation.
// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
unsigned LastEmittedCodeSynthesisContextDepth = 0;

/// The template instantiation callbacks to trace or track
/// instantiations (objects can be chained).
///
/// This callbacks is used to print, trace or track template
/// instantiations as they are being constructed.
std::vector<std::unique_ptr<TemplateInstantiationCallback>>
    TemplateInstCallbacks;

/// The current index into pack expansion arguments that will be
/// used for substitution of parameter packs.
///
/// The pack expansion index will be -1 to indicate that parameter packs
/// should be instantiated as themselves. Otherwise, the index specifies
/// which argument within the parameter pack will be used for substitution.
int ArgumentPackSubstitutionIndex;

/// RAII object used to change the argument pack substitution index
/// within a \c Sema object.
///
/// See \c ArgumentPackSubstitutionIndex for more information.
class ArgumentPackSubstitutionIndexRAII {
  Sema &Self;
  int OldSubstitutionIndex;

public:
  ArgumentPackSubstitutionIndexRAII(Sema &Self, int NewSubstitutionIndex)
    : Self(Self), OldSubstitutionIndex(Self.ArgumentPackSubstitutionIndex) {
    Self.ArgumentPackSubstitutionIndex = NewSubstitutionIndex;
  }

  ~ArgumentPackSubstitutionIndexRAII() {
    Self.ArgumentPackSubstitutionIndex = OldSubstitutionIndex;
  }
};

friend class ArgumentPackSubstitutionRAII;

/// For each declaration that involved template argument deduction, the
/// set of diagnostics that were suppressed during that template argument
/// deduction.
///
/// FIXME: Serialize this structure to the AST file.
typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, 1> >
  SuppressedDiagnosticsMap;
SuppressedDiagnosticsMap SuppressedDiagnostics;

/// A stack object to be created when performing template
/// instantiation.
///
/// Construction of an object of type \c InstantiatingTemplate
/// pushes the current instantiation onto the stack of active
/// instantiations. If the size of this stack exceeds the maximum
/// number of recursive template instantiations, construction
/// produces an error and evaluates true.
///
/// Destruction of this object will pop the named instantiation off
/// the stack.
struct InstantiatingTemplate {
  /// Note that we are instantiating a class template,
  /// function template, variable template, alias template,
  /// or a member thereof.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        Decl *Entity,
                        SourceRange InstantiationRange = SourceRange());

  struct ExceptionSpecification {};
  /// Note that we are instantiating an exception specification
  /// of a function template.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionDecl *Entity, ExceptionSpecification,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument in a
  /// template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateParameter Param, TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting either explicitly-specified or
  /// deduced template arguments during function template argument deduction.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionTemplateDecl *FunctionTemplate,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        CodeSynthesisContext::SynthesisKind Kind,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template declaration.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ClassTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a variable template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        VarTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument for a function
  /// parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ParmVarDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting prior template arguments into a
  /// non-type parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        NonTypeTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are substituting prior template arguments into a
  /// template template parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        TemplateTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are checking the default template argument
  /// against the template parameter for a given template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        NamedDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  struct ConstraintsCheck {};
  /// \brief Note that we are checking the constraints associated with some
  /// constrained entity (a concept declaration or a template with associated
  /// constraints).
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintsCheck, NamedDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  struct ConstraintSubstitution {};
  /// \brief Note that we are checking a constraint expression associated
  /// with a template declaration or as part of the satisfaction check of a
  /// concept.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintSubstitution, NamedDecl *Template,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange);

  struct ConstraintNormalization {};
  /// \brief Note that we are normalizing a constraint expression.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintNormalization, NamedDecl *Template,
                        SourceRange InstantiationRange);

  struct ParameterMappingSubstitution {};
  /// \brief Note that we are subtituting into the parameter mapping of an
  /// atomic constraint during constraint normalization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ParameterMappingSubstitution, NamedDecl *Template,
                        SourceRange InstantiationRange);

  /// \brief Note that we are substituting template arguments into a part of
  /// a requirement of a requires expression.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        concepts::Requirement *Req,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// \brief Note that we are checking the satisfaction of the constraint
  /// expression inside of a nested requirement.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        concepts::NestedRequirement *Req, ConstraintsCheck,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we have finished instantiating this template.
  void Clear();

  ~InstantiatingTemplate() { Clear(); }

  /// Determines whether we have exceeded the maximum
  /// recursive template instantiations.
  bool isInvalid() const { return Invalid; }

  /// Determine whether we are already instantiating this
  /// specialization in some surrounding active instantiation.
  bool isAlreadyInstantiating() const { return AlreadyInstantiating; }

private:
  Sema &SemaRef;
  bool Invalid;
  bool AlreadyInstantiating;
  bool CheckInstantiationDepth(SourceLocation PointOfInstantiation,
                               SourceRange InstantiationRange);

  InstantiatingTemplate(
      Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
      SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
      Decl *Entity, NamedDecl *Template = nullptr,
      ArrayRef<TemplateArgument> TemplateArgs = None,
      sema::TemplateDeductionInfo *DeductionInfo = nullptr);

  InstantiatingTemplate(const InstantiatingTemplate&) = delete;

  InstantiatingTemplate&
  operator=(const InstantiatingTemplate&) = delete;
};

void pushCodeSynthesisContext(CodeSynthesisContext Ctx);
void popCodeSynthesisContext();

/// Determine whether we are currently performing template instantiation.
bool inTemplateInstantiation() const {
  return CodeSynthesisContexts.size() > NonInstantiationEntries;
}

void PrintContextStack() {
  if (!CodeSynthesisContexts.empty() &&
      CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
    PrintInstantiationStack();
    LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
  }
  if (PragmaAttributeCurrentTargetDecl)
    PrintPragmaAttributeInstantiationPoint();
}
void PrintInstantiationStack();

void PrintPragmaAttributeInstantiationPoint();

/// Determines whether we are currently in a context where
/// template argument substitution failures are not considered
/// errors.
///
/// \returns An empty \c Optional if we're not in a SFINAE context.
/// Otherwise, contains a pointer that, if non-NULL, contains the nearest
/// template-deduction context object, which can be used to capture
/// diagnostics that will be suppressed.
Optional<sema::TemplateDeductionInfo *> isSFINAEContext() const;

/// Determines whether we are currently in a context that
/// is not evaluated as per C++ [expr] p5.
bool isUnevaluatedContext() const {
  assert(!ExprEvalContexts.empty() &&((void)0)
         "Must be in an expression evaluation context")((void)0);
  return ExprEvalContexts.back().isUnevaluated();
}

/// RAII class used to determine whether SFINAE has
/// trapped any errors that occur during template argument
/// deduction.
class SFINAETrap {
  Sema &SemaRef;
  unsigned PrevSFINAEErrors;
  bool PrevInNonInstantiationSFINAEContext;
  bool PrevAccessCheckingSFINAE;
  bool PrevLastDiagnosticIgnored;

public:
  explicit SFINAETrap(Sema &SemaRef, bool AccessCheckingSFINAE = false)
    : SemaRef(SemaRef), PrevSFINAEErrors(SemaRef.NumSFINAEErrors),
      PrevInNonInstantiationSFINAEContext(
                                    SemaRef.InNonInstantiationSFINAEContext),
      PrevAccessCheckingSFINAE(SemaRef.AccessCheckingSFINAE),
      PrevLastDiagnosticIgnored(
          SemaRef.getDiagnostics().isLastDiagnosticIgnored())
  {
    if (!SemaRef.isSFINAEContext())
      SemaRef.InNonInstantiationSFINAEContext = true;
    SemaRef.AccessCheckingSFINAE = AccessCheckingSFINAE;
  }

  ~SFINAETrap() {
    SemaRef.NumSFINAEErrors = PrevSFINAEErrors;
    SemaRef.InNonInstantiationSFINAEContext
      = PrevInNonInstantiationSFINAEContext;
    SemaRef.AccessCheckingSFINAE = PrevAccessCheckingSFINAE;
    SemaRef.getDiagnostics().setLastDiagnosticIgnored(
        PrevLastDiagnosticIgnored);
  }

  /// Determine whether any SFINAE errors have been trapped.
  bool hasErrorOccurred() const {
    return SemaRef.NumSFINAEErrors > PrevSFINAEErrors;
  }
};

/// RAII class used to indicate that we are performing provisional
/// semantic analysis to determine the validity of a construct, so
/// typo-correction and diagnostics in the immediate context (not within
/// implicitly-instantiated templates) should be suppressed.
class TentativeAnalysisScope {
  Sema &SemaRef;
  // FIXME: Using a SFINAETrap for this is a hack.
  SFINAETrap Trap;
  bool PrevDisableTypoCorrection;
public:
  explicit TentativeAnalysisScope(Sema &SemaRef)
      : SemaRef(SemaRef), Trap(SemaRef, true),
        PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
    SemaRef.DisableTypoCorrection = true;
  }
  ~TentativeAnalysisScope() {
    SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
  }
};

/// The current instantiation scope used to store local
/// variables.
LocalInstantiationScope *CurrentInstantiationScope;

/// Tracks whether we are in a context where typo correction is
/// disabled.
bool DisableTypoCorrection;

/// The number of typos corrected by CorrectTypo.
unsigned TyposCorrected;

typedef llvm::SmallSet<SourceLocation, 2> SrcLocSet;
typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;

/// A cache containing identifiers for which typo correction failed and
/// their locations, so that repeated attempts to correct an identifier in a
/// given location are ignored if typo correction already failed for it.
IdentifierSourceLocations TypoCorrectionFailures;

/// Worker object for performing CFG-based warnings.
sema::AnalysisBasedWarnings AnalysisWarnings;
threadSafety::BeforeSet *ThreadSafetyDeclCache;

/// An entity for which implicit template instantiation is required.
///
/// The source location associated with the declaration is the first place in
/// the source code where the declaration was "used". It is not necessarily
/// the point of instantiation (which will be either before or after the
/// namespace-scope declaration that triggered this implicit instantiation),
/// However, it is the location that diagnostics should generally refer to,
/// because users will need to know what code triggered the instantiation.
typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;

/// The queue of implicit template instantiations that are required
/// but have not yet been performed.
std::deque<PendingImplicitInstantiation> PendingInstantiations;

/// Queue of implicit template instantiations that cannot be performed
/// eagerly.
SmallVector<PendingImplicitInstantiation, 1> LateParsedInstantiations;

class GlobalEagerInstantiationScope {
public:
  GlobalEagerInstantiationScope(Sema &S, bool Enabled)
      : S(S), Enabled(Enabled) {
    if (!Enabled) return;

    SavedPendingInstantiations.swap(S.PendingInstantiations);
    SavedVTableUses.swap(S.VTableUses);
  }

  void perform() {
    if (Enabled) {
      S.DefineUsedVTables();
      S.PerformPendingInstantiations();
    }
  }

  ~GlobalEagerInstantiationScope() {
    if (!Enabled) return;

    // Restore the set of pending vtables.
    assert(S.VTableUses.empty() &&((void)0)
           "VTableUses should be empty before it is discarded.")((void)0);
    S.VTableUses.swap(SavedVTableUses);

    // Restore the set of pending implicit instantiations.
    if (S.TUKind != TU_Prefix || !S.LangOpts.PCHInstantiateTemplates) {
      assert(S.PendingInstantiations.empty() &&((void)0)
             "PendingInstantiations should be empty before it is discarded.")((void)0);
      S.PendingInstantiations.swap(SavedPendingInstantiations);
    } else {
      // Template instantiations in the PCH may be delayed until the TU.
      S.PendingInstantiations.swap(SavedPendingInstantiations);
      S.PendingInstantiations.insert(S.PendingInstantiations.end(),
                                     SavedPendingInstantiations.begin(),
                                     SavedPendingInstantiations.end());
    }
  }

private:
  Sema &S;
  SmallVector<VTableUse, 16> SavedVTableUses;
  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
  bool Enabled;
};

/// The queue of implicit template instantiations that are required
/// and must be performed within the current local scope.
///
/// This queue is only used for member functions of local classes in
/// templates, which must be instantiated in the same scope as their
/// enclosing function, so that they can reference function-local
/// types, static variables, enumerators, etc.
std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;

class LocalEagerInstantiationScope {
public:
  LocalEagerInstantiationScope(Sema &S) : S(S) {
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

  void perform() { S.PerformPendingInstantiations(/*LocalOnly=*/true); }

  ~LocalEagerInstantiationScope() {
    assert(S.PendingLocalImplicitInstantiations.empty() &&((void)0)
           "there shouldn't be any pending local implicit instantiations")((void)0);
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

private:
  Sema &S;
  std::deque<PendingImplicitInstantiation>
      SavedPendingLocalImplicitInstantiations;
};

/// A helper class for building up ExtParameterInfos.
class ExtParameterInfoBuilder {
  SmallVector<FunctionProtoType::ExtParameterInfo, 16> Infos;
  bool HasInteresting = false;

public:
  /// Set the ExtParameterInfo for the parameter at the given index,
  ///
  void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
    assert(Infos.size() <= index)((void)0);
    Infos.resize(index);
    Infos.push_back(info);

    if (!HasInteresting)
      HasInteresting = (info != FunctionProtoType::ExtParameterInfo());
  }

  /// Return a pointer (suitable for setting in an ExtProtoInfo) to the
  /// ExtParameterInfo array we've built up.
  const FunctionProtoType::ExtParameterInfo *
  getPointerOrNull(unsigned numParams) {
    if (!HasInteresting) return nullptr;
    Infos.resize(numParams);
    return Infos.data();
  }
};

void PerformPendingInstantiations(bool LocalOnly = false);

TypeSourceInfo *SubstType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity,
                          bool AllowDeducedTST = false);

QualType SubstType(QualType T,
                   const MultiLevelTemplateArgumentList &TemplateArgs,
                   SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstType(TypeLoc TL,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstFunctionDeclType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                      SourceLocation Loc,
                                      DeclarationName Entity,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals);
void SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                        const MultiLevelTemplateArgumentList &Args);
bool SubstExceptionSpec(SourceLocation Loc,
                        FunctionProtoType::ExceptionSpecInfo &ESI,
                        SmallVectorImpl<QualType> &ExceptionStorage,
                        const MultiLevelTemplateArgumentList &Args);
ParmVarDecl *SubstParmVarDecl(ParmVarDecl *D,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                              int indexAdjustment,
                              Optional<unsigned> NumExpansions,
                              bool ExpectParameterPack);
bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
                    const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
                    const MultiLevelTemplateArgumentList &TemplateArgs,
                    SmallVectorImpl<QualType> &ParamTypes,
                    SmallVectorImpl<ParmVarDecl *> *OutParams,
                    ExtParameterInfoBuilder &ParamInfos);
ExprResult SubstExpr(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

/// Substitute the given template arguments into a list of
/// expressions, expanding pack expansions if required.
///
/// \param Exprs The list of expressions to substitute into.
///
/// \param IsCall Whether this is some form of call, in which case
/// default arguments will be dropped.
///
/// \param TemplateArgs The set of template arguments to substitute.
///
/// \param Outputs Will receive all of the substituted arguments.
///
/// \returns true if an error occurred, false otherwise.
bool SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall,
                const MultiLevelTemplateArgumentList &TemplateArgs,
                SmallVectorImpl<Expr *> &Outputs);

StmtResult SubstStmt(Stmt *S,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

TemplateParameterList *
SubstTemplateParams(TemplateParameterList *Params, DeclContext *Owner,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

bool
SubstTemplateArguments(ArrayRef<TemplateArgumentLoc> Args,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       TemplateArgumentListInfo &Outputs);


Decl *SubstDecl(Decl *D, DeclContext *Owner,
                const MultiLevelTemplateArgumentList &TemplateArgs);

/// Substitute the name and return type of a defaulted 'operator<=>' to form
/// an implicit 'operator=='.
FunctionDecl *SubstSpaceshipAsEqualEqual(CXXRecordDecl *RD,
                                         FunctionDecl *Spaceship);

ExprResult SubstInitializer(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     bool CXXDirectInit);

bool
SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                    CXXRecordDecl *Pattern,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

bool
InstantiateClass(SourceLocation PointOfInstantiation,
                 CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                 const MultiLevelTemplateArgumentList &TemplateArgs,
                 TemplateSpecializationKind TSK,
                 bool Complain = true);

bool InstantiateEnum(SourceLocation PointOfInstantiation,
                     EnumDecl *Instantiation, EnumDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK);

bool InstantiateInClassInitializer(
    SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
    FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs);

struct LateInstantiatedAttribute {
  const Attr *TmplAttr;
  LocalInstantiationScope *Scope;
  Decl *NewDecl;

  LateInstantiatedAttribute(const Attr *A, LocalInstantiationScope *S,
                            Decl *D)
    : TmplAttr(A), Scope(S), NewDecl(D)
  { }
};
typedef SmallVector<LateInstantiatedAttribute, 16> LateInstantiatedAttrVec;

void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                      const Decl *Pattern, Decl *Inst,
                      LateInstantiatedAttrVec *LateAttrs = nullptr,
                      LocalInstantiationScope *OuterMostScope = nullptr);

void
InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
                        const Decl *Pattern, Decl *Inst,
                        LateInstantiatedAttrVec *LateAttrs = nullptr,
                        LocalInstantiationScope *OuterMostScope = nullptr);

void InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor);

bool usesPartialOrExplicitSpecialization(
    SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);

bool
InstantiateClassTemplateSpecialization(SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                         TemplateSpecializationKind TSK,
                         bool Complain = true);

void InstantiateClassMembers(SourceLocation PointOfInstantiation,
                             CXXRecordDecl *Instantiation,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                             TemplateSpecializationKind TSK);

void InstantiateClassTemplateSpecializationMembers(
                                        SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                                              TemplateSpecializationKind TSK);

NestedNameSpecifierLoc
SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
                         const MultiLevelTemplateArgumentList &TemplateArgs);

DeclarationNameInfo
SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
                         const MultiLevelTemplateArgumentList &TemplateArgs);
TemplateName
SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, TemplateName Name,
                  SourceLocation Loc,
                  const MultiLevelTemplateArgumentList &TemplateArgs);
bool Subst(const TemplateArgumentLoc *Args, unsigned NumArgs,
           TemplateArgumentListInfo &Result,
           const MultiLevelTemplateArgumentList &TemplateArgs);

bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
                                ParmVarDecl *Param);
void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
                              FunctionDecl *Function);
bool CheckInstantiatedFunctionTemplateConstraints(
    SourceLocation PointOfInstantiation, FunctionDecl *Decl,
    ArrayRef<TemplateArgument> TemplateArgs,
    ConstraintSatisfaction &Satisfaction);
FunctionDecl *InstantiateFunctionDeclaration(FunctionTemplateDecl *FTD,
                                             const TemplateArgumentList *Args,
                                             SourceLocation Loc);
void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
                                   FunctionDecl *Function,
                                   bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);
VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
    VarTemplateDecl *VarTemplate, VarDecl *FromVar,
    const TemplateArgumentList &TemplateArgList,
    const TemplateArgumentListInfo &TemplateArgsInfo,
    SmallVectorImpl<TemplateArgument> &Converted,
    SourceLocation PointOfInstantiation,
    LateInstantiatedAttrVec *LateAttrs = nullptr,
    LocalInstantiationScope *StartingScope = nullptr);
VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
    VarTemplateSpecializationDecl *VarSpec, VarDecl *PatternDecl,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void
BuildVariableInstantiation(VarDecl *NewVar, VarDecl *OldVar,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                           LateInstantiatedAttrVec *LateAttrs,
                           DeclContext *Owner,
                           LocalInstantiationScope *StartingScope,
                           bool InstantiatingVarTemplate = false,
                           VarTemplateSpecializationDecl *PrevVTSD = nullptr);

void InstantiateVariableInitializer(
    VarDecl *Var, VarDecl *OldVar,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
                                   VarDecl *Var, bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);

void InstantiateMemInitializers(CXXConstructorDecl *New,
                                const CXXConstructorDecl *Tmpl,
                          const MultiLevelTemplateArgumentList &TemplateArgs);

NamedDecl *FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
                        const MultiLevelTemplateArgumentList &TemplateArgs,
                        bool FindingInstantiatedContext = false);
DeclContext *FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
                        const MultiLevelTemplateArgumentList &TemplateArgs);

// Objective-C declarations.
enum ObjCContainerKind {
  OCK_None = -1,
  OCK_Interface = 0,
  OCK_Protocol,
  OCK_Category,
  OCK_ClassExtension,
  OCK_Implementation,
  OCK_CategoryImplementation
};
ObjCContainerKind getObjCContainerKind() const;

DeclResult actOnObjCTypeParam(Scope *S,
                              ObjCTypeParamVariance variance,
                              SourceLocation varianceLoc,
                              unsigned index,
                              IdentifierInfo *paramName,
                              SourceLocation paramLoc,
                              SourceLocation colonLoc,
                              ParsedType typeBound);

ObjCTypeParamList *actOnObjCTypeParamList(Scope *S, SourceLocation lAngleLoc,
                                          ArrayRef<Decl *> typeParams,
                                          SourceLocation rAngleLoc);
void popObjCTypeParamList(Scope *S, ObjCTypeParamList *typeParamList);

Decl *ActOnStartClassInterface(
    Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *SuperName, SourceLocation SuperLoc,
    ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

void ActOnSuperClassOfClassInterface(Scope *S,
                                     SourceLocation AtInterfaceLoc,
                                     ObjCInterfaceDecl *IDecl,
                                     IdentifierInfo *ClassName,
                                     SourceLocation ClassLoc,
                                     IdentifierInfo *SuperName,
                                     SourceLocation SuperLoc,
                                     ArrayRef<ParsedType> SuperTypeArgs,
                                     SourceRange SuperTypeArgsRange);

void ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
                             SmallVectorImpl<SourceLocation> &ProtocolLocs,
                             IdentifierInfo *SuperName,
                             SourceLocation SuperLoc);

Decl *ActOnCompatibilityAlias(
                  SourceLocation AtCompatibilityAliasLoc,
                  IdentifierInfo *AliasName,  SourceLocation AliasLocation,
                  IdentifierInfo *ClassName, SourceLocation ClassLocation);

bool CheckForwardProtocolDeclarationForCircularDependency(
  IdentifierInfo *PName,
  SourceLocation &PLoc, SourceLocation PrevLoc,
  const ObjCList<ObjCProtocolDecl> &PList);

Decl *ActOnStartProtocolInterface(
    SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
    SourceLocation ProtocolLoc, Decl *const *ProtoRefNames,
    unsigned NumProtoRefs, const SourceLocation *ProtoLocs,
    SourceLocation EndProtoLoc, const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryInterface(
    SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

Decl *ActOnStartClassImplementation(SourceLocation AtClassImplLoc,
                                    IdentifierInfo *ClassName,
                                    SourceLocation ClassLoc,
                                    IdentifierInfo *SuperClassname,
                                    SourceLocation SuperClassLoc,
                                    const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryImplementation(SourceLocation AtCatImplLoc,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassLoc,
                                       IdentifierInfo *CatName,
                                       SourceLocation CatLoc,
                                       const ParsedAttributesView &AttrList);

DeclGroupPtrTy ActOnFinishObjCImplementation(Decl *ObjCImpDecl,
                                             ArrayRef<Decl *> Decls);

DeclGroupPtrTy ActOnForwardClassDeclaration(SourceLocation Loc,
                 IdentifierInfo **IdentList,
                 SourceLocation *IdentLocs,
                 ArrayRef<ObjCTypeParamList *> TypeParamLists,
                 unsigned NumElts);

DeclGroupPtrTy
ActOnForwardProtocolDeclaration(SourceLocation AtProtoclLoc,
                                ArrayRef<IdentifierLocPair> IdentList,
                                const ParsedAttributesView &attrList);

void FindProtocolDeclaration(bool WarnOnDeclarations, bool ForObjCContainer,
                             ArrayRef<IdentifierLocPair> ProtocolId,
                             SmallVectorImpl<Decl *> &Protocols);

void DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
                                  SourceLocation ProtocolLoc,
                                  IdentifierInfo *TypeArgId,
                                  SourceLocation TypeArgLoc,
                                  bool SelectProtocolFirst = false);

/// Given a list of identifiers (and their locations), resolve the
/// names to either Objective-C protocol qualifiers or type
/// arguments, as appropriate.
void actOnObjCTypeArgsOrProtocolQualifiers(
       Scope *S,
       ParsedType baseType,
       SourceLocation lAngleLoc,
       ArrayRef<IdentifierInfo *> identifiers,
       ArrayRef<SourceLocation> identifierLocs,
       SourceLocation rAngleLoc,
       SourceLocation &typeArgsLAngleLoc,
       SmallVectorImpl<ParsedType> &typeArgs,
       SourceLocation &typeArgsRAngleLoc,
       SourceLocation &protocolLAngleLoc,
       SmallVectorImpl<Decl *> &protocols,
       SourceLocation &protocolRAngleLoc,
       bool warnOnIncompleteProtocols);

/// Build a an Objective-C protocol-qualified 'id' type where no
/// base type was specified.
TypeResult actOnObjCProtocolQualifierType(
             SourceLocation lAngleLoc,
             ArrayRef<Decl *> protocols,
             ArrayRef<SourceLocation> protocolLocs,
             SourceLocation rAngleLoc);

/// Build a specialized and/or protocol-qualified Objective-C type.
TypeResult actOnObjCTypeArgsAndProtocolQualifiers(
             Scope *S,
             SourceLocation Loc,
             ParsedType BaseType,
             SourceLocation TypeArgsLAngleLoc,
             ArrayRef<ParsedType> TypeArgs,
             SourceLocation TypeArgsRAngleLoc,
             SourceLocation ProtocolLAngleLoc,
             ArrayRef<Decl *> Protocols,
             ArrayRef<SourceLocation> ProtocolLocs,
             SourceLocation ProtocolRAngleLoc);

/// Build an Objective-C type parameter type.
QualType BuildObjCTypeParamType(const ObjCTypeParamDecl *Decl,
                                SourceLocation ProtocolLAngleLoc,
                                ArrayRef<ObjCProtocolDecl *> Protocols,
                                ArrayRef<SourceLocation> ProtocolLocs,
                                SourceLocation ProtocolRAngleLoc,
                                bool FailOnError = false);

/// Build an Objective-C object pointer type.
QualType BuildObjCObjectType(QualType BaseType,
                             SourceLocation Loc,
                             SourceLocation TypeArgsLAngleLoc,
                             ArrayRef<TypeSourceInfo *> TypeArgs,
                             SourceLocation TypeArgsRAngleLoc,
                             SourceLocation ProtocolLAngleLoc,
                             ArrayRef<ObjCProtocolDecl *> Protocols,
                             ArrayRef<SourceLocation> ProtocolLocs,
                             SourceLocation ProtocolRAngleLoc,
                             bool FailOnError = false);

/// Ensure attributes are consistent with type.
/// \param [in, out] Attributes The attributes to check; they will
/// be modified to be consistent with \p PropertyTy.
void CheckObjCPropertyAttributes(Decl *PropertyPtrTy,
                                 SourceLocation Loc,
                                 unsigned &Attributes,
                                 bool propertyInPrimaryClass);

/// Process the specified property declaration and create decls for the
/// setters and getters as needed.
/// \param property The property declaration being processed
void ProcessPropertyDecl(ObjCPropertyDecl *property);


void DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
                              ObjCPropertyDecl *SuperProperty,
                              const IdentifierInfo *Name,
                              bool OverridingProtocolProperty);

void DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
                                      ObjCInterfaceDecl *ID);

Decl *ActOnAtEnd(Scope *S, SourceRange AtEnd,
                 ArrayRef<Decl *> allMethods = None,
                 ArrayRef<DeclGroupPtrTy> allTUVars = None);

Decl *ActOnProperty(Scope *S, SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD, ObjCDeclSpec &ODS,
                    Selector GetterSel, Selector SetterSel,
                    tok::ObjCKeywordKind MethodImplKind,
                    DeclContext *lexicalDC = nullptr);

Decl *ActOnPropertyImplDecl(Scope *S,
                            SourceLocation AtLoc,
                            SourceLocation PropertyLoc,
                            bool ImplKind,
                            IdentifierInfo *PropertyId,
                            IdentifierInfo *PropertyIvar,
                            SourceLocation PropertyIvarLoc,
                            ObjCPropertyQueryKind QueryKind);

enum ObjCSpecialMethodKind {
  OSMK_None,
  OSMK_Alloc,
  OSMK_New,
  OSMK_Copy,
  OSMK_RetainingInit,
  OSMK_NonRetainingInit
};

struct ObjCArgInfo {
  IdentifierInfo *Name;
  SourceLocation NameLoc;
  // The Type is null if no type was specified, and the DeclSpec is invalid
  // in this case.
  ParsedType Type;
  ObjCDeclSpec DeclSpec;

  /// ArgAttrs - Attribute list for this argument.
  ParsedAttributesView ArgAttrs;
};

Decl *ActOnMethodDeclaration(
    Scope *S,
    SourceLocation BeginLoc, // location of the + or -.
    SourceLocation EndLoc,   // location of the ; or {.
    tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
    ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
    // optional arguments. The number of types/arguments is obtained
    // from the Sel.getNumArgs().
    ObjCArgInfo *ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
    unsigned CNumArgs, // c-style args
    const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodImplKind,
    bool isVariadic, bool MethodDefinition);

ObjCMethodDecl *LookupMethodInQualifiedType(Selector Sel,
                                            const ObjCObjectPointerType *OPT,
                                            bool IsInstance);
ObjCMethodDecl *LookupMethodInObjectType(Selector Sel, QualType Ty,
                                         bool IsInstance);

bool CheckARCMethodDecl(ObjCMethodDecl *method);
bool inferObjCARCLifetime(ValueDecl *decl);

void deduceOpenCLAddressSpace(ValueDecl *decl);

ExprResult
HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
                          Expr *BaseExpr,
                          SourceLocation OpLoc,
                          DeclarationName MemberName,
                          SourceLocation MemberLoc,
                          SourceLocation SuperLoc, QualType SuperType,
                          bool Super);

ExprResult
ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
                          IdentifierInfo &propertyName,
                          SourceLocation receiverNameLoc,
                          SourceLocation propertyNameLoc);

ObjCMethodDecl *tryCaptureObjCSelf(SourceLocation Loc);

/// Describes the kind of message expression indicated by a message
/// send that starts with an identifier.
enum ObjCMessageKind {
  /// The message is sent to 'super'.
  ObjCSuperMessage,
  /// The message is an instance message.
  ObjCInstanceMessage,
  /// The message is a class message, and the identifier is a type
  /// name.
  ObjCClassMessage
};

ObjCMessageKind getObjCMessageKind(Scope *S,
                                   IdentifierInfo *Name,
                                   SourceLocation NameLoc,
                                   bool IsSuper,
                                   bool HasTrailingDot,
                                   ParsedType &ReceiverType);

ExprResult ActOnSuperMessage(Scope *S, SourceLocation SuperLoc,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
                             QualType ReceiverType,
                             SourceLocation SuperLoc,
                             Selector Sel,
                             ObjCMethodDecl *Method,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args,
                             bool isImplicit = false);

ExprResult BuildClassMessageImplicit(QualType ReceiverType,
                                     bool isSuperReceiver,
                                     SourceLocation Loc,
                                     Selector Sel,
                                     ObjCMethodDecl *Method,
                                     MultiExprArg Args);

ExprResult ActOnClassMessage(Scope *S,
                             ParsedType Receiver,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildInstanceMessage(Expr *Receiver,
                                QualType ReceiverType,
                                SourceLocation SuperLoc,
                                Selector Sel,
                                ObjCMethodDecl *Method,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args,
                                bool isImplicit = false);

ExprResult BuildInstanceMessageImplicit(Expr *Receiver,
                                        QualType ReceiverType,
                                        SourceLocation Loc,
                                        Selector Sel,
                                        ObjCMethodDecl *Method,
                                        MultiExprArg Args);

ExprResult ActOnInstanceMessage(Scope *S,
                                Expr *Receiver,
                                Selector Sel,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args);

ExprResult BuildObjCBridgedCast(SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                TypeSourceInfo *TSInfo,
                                Expr *SubExpr);

ExprResult ActOnObjCBridgedCast(Scope *S,
                                SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                ParsedType Type,
                                SourceLocation RParenLoc,
                                Expr *SubExpr);

void CheckTollFreeBridgeCast(QualType castType, Expr *castExpr);

void CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr);

bool CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
                                   CastKind &Kind);

bool checkObjCBridgeRelatedComponents(SourceLocation Loc,
                                      QualType DestType, QualType SrcType,
                                      ObjCInterfaceDecl *&RelatedClass,
                                      ObjCMethodDecl *&ClassMethod,
                                      ObjCMethodDecl *&InstanceMethod,
                                      TypedefNameDecl *&TDNDecl,
                                      bool CfToNs, bool Diagnose = true);

bool CheckObjCBridgeRelatedConversions(SourceLocation Loc,
                                       QualType DestType, QualType SrcType,
                                       Expr *&SrcExpr, bool Diagnose = true);

bool CheckConversionToObjCLiteral(QualType DstType, Expr *&SrcExpr,
                                  bool Diagnose = true);

bool checkInitMethod(ObjCMethodDecl *method, QualType receiverTypeIfCall);

/// Check whether the given new method is a valid override of the
/// given overridden method, and set any properties that should be inherited.
void CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
                             const ObjCMethodDecl *Overridden);

/// Describes the compatibility of a result type with its method.
enum ResultTypeCompatibilityKind {
  RTC_Compatible,
  RTC_Incompatible,
  RTC_Unknown
};

void CheckObjCMethodDirectOverrides(ObjCMethodDecl *method,
                                    ObjCMethodDecl *overridden);

void CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
                              ObjCInterfaceDecl *CurrentClass,
                              ResultTypeCompatibilityKind RTC);

enum PragmaOptionsAlignKind {
  POAK_Native,  // #pragma options align=native
  POAK_Natural, // #pragma options align=natural
  POAK_Packed,  // #pragma options align=packed
  POAK_Power,   // #pragma options align=power
  POAK_Mac68k,  // #pragma options align=mac68k
  POAK_Reset    // #pragma options align=reset
};

/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
void ActOnPragmaClangSection(SourceLocation PragmaLoc,
                             PragmaClangSectionAction Action,
                             PragmaClangSectionKind SecKind, StringRef SecName);

/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
                             SourceLocation PragmaLoc);

/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
                     StringRef SlotLabel, Expr *Alignment);

enum class PragmaAlignPackDiagnoseKind {
  NonDefaultStateAtInclude,
  ChangedStateAtExit
};

void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
                                       SourceLocation IncludeLoc);
void DiagnoseUnterminatedPragmaAlignPack();

/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on|off].
void ActOnPragmaMSStruct(PragmaMSStructKind Kind);

/// ActOnPragmaMSComment - Called on well formed
/// \#pragma comment(kind, "arg").
void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
                          StringRef Arg);

/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
/// pointers_to_members(representation method[, general purpose
/// representation]).
void ActOnPragmaMSPointersToMembers(
    LangOptions::PragmaMSPointersToMembersKind Kind,
    SourceLocation PragmaLoc);

/// Called on well formed \#pragma vtordisp().
void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
                           SourceLocation PragmaLoc,
                           MSVtorDispMode Value);

enum PragmaSectionKind {
  PSK_DataSeg,
  PSK_BSSSeg,
  PSK_ConstSeg,
  PSK_CodeSeg,
};

bool UnifySection(StringRef SectionName, int SectionFlags,
                  NamedDecl *TheDecl);
bool UnifySection(StringRef SectionName,
                  int SectionFlags,
                  SourceLocation PragmaSectionLocation);

/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
                      PragmaMsStackAction Action,
                      llvm::StringRef StackSlotLabel,
                      StringLiteral *SegmentName,
                      llvm::StringRef PragmaName);

/// Called on well formed \#pragma section().
void ActOnPragmaMSSection(SourceLocation PragmaLocation,
                          int SectionFlags, StringLiteral *SegmentName);

/// Called on well-formed \#pragma init_seg().
void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
                          StringLiteral *SegmentName);

/// Called on #pragma clang __debug dump II
void ActOnPragmaDump(Scope *S, SourceLocation Loc, IdentifierInfo *II);

/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
                               StringRef Value);

/// Are precise floating point semantics currently enabled?
bool isPreciseFPEnabled() {
  return !CurFPFeatures.getAllowFPReassociate() &&
         !CurFPFeatures.getNoSignedZero() &&
         !CurFPFeatures.getAllowReciprocal() &&
         !CurFPFeatures.getAllowApproxFunc();
}

/// ActOnPragmaFloatControl - Call on well-formed \#pragma float_control
void ActOnPragmaFloatControl(SourceLocation Loc, PragmaMsStackAction Action,
                             PragmaFloatControlKind Value);

/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
void ActOnPragmaUnused(const Token &Identifier,
                       Scope *curScope,
                       SourceLocation PragmaLoc);

/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
void ActOnPragmaVisibility(const IdentifierInfo* VisType,
                           SourceLocation PragmaLoc);

NamedDecl *DeclClonePragmaWeak(NamedDecl *ND, IdentifierInfo *II,
                               SourceLocation Loc);
void DeclApplyPragmaWeak(Scope *S, NamedDecl *ND, WeakInfo &W);

/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
void ActOnPragmaWeakID(IdentifierInfo* WeakName,
                       SourceLocation PragmaLoc,
                       SourceLocation WeakNameLoc);

/// ActOnPragmaRedefineExtname - Called on well formed
/// \#pragma redefine_extname oldname newname.
void ActOnPragmaRedefineExtname(IdentifierInfo* WeakName,
                                IdentifierInfo* AliasName,
                                SourceLocation PragmaLoc,
                                SourceLocation WeakNameLoc,
                                SourceLocation AliasNameLoc);

/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
void ActOnPragmaWeakAlias(IdentifierInfo* WeakName,
                          IdentifierInfo* AliasName,
                          SourceLocation PragmaLoc,
                          SourceLocation WeakNameLoc,
                          SourceLocation AliasNameLoc);

/// ActOnPragmaFPContract - Called on well formed
/// \#pragma {STDC,OPENCL} FP_CONTRACT and
/// \#pragma clang fp contract
void ActOnPragmaFPContract(SourceLocation Loc, LangOptions::FPModeKind FPC);

/// Called on well formed
/// \#pragma clang fp reassociate
void ActOnPragmaFPReassociate(SourceLocation Loc, bool IsEnabled);

/// ActOnPragmaFenvAccess - Called on well formed
/// \#pragma STDC FENV_ACCESS
void ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled);

/// Called on well formed '\#pragma clang fp' that has option 'exceptions'.
void ActOnPragmaFPExceptions(SourceLocation Loc,
                             LangOptions::FPExceptionModeKind);

/// Called to set constant rounding mode for floating point operations.
void setRoundingMode(SourceLocation Loc, llvm::RoundingMode);

/// Called to set exception behavior for floating point operations.
void setExceptionMode(SourceLocation Loc, LangOptions::FPExceptionModeKind);

/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
void AddAlignmentAttributesForRecord(RecordDecl *RD);

/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
void AddMsStructLayoutForRecord(RecordDecl *RD);

/// PushNamespaceVisibilityAttr - Note that we've entered a
/// namespace with a visibility attribute.
void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
                                 SourceLocation Loc);

/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
/// add an appropriate visibility attribute.
void AddPushedVisibilityAttribute(Decl *RD);

/// PopPragmaVisibility - Pop the top element of the visibility stack; used
/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);

/// FreeVisContext - Deallocate and null out VisContext.
void FreeVisContext();

/// AddCFAuditedAttribute - Check whether we're currently within
/// '\#pragma clang arc_cf_code_audited' and, if so, consider adding
/// the appropriate attribute.
void AddCFAuditedAttribute(Decl *D);

void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
                                   SourceLocation PragmaLoc,
                                   attr::ParsedSubjectMatchRuleSet Rules);
void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
                                   const IdentifierInfo *Namespace);

/// Called on well-formed '\#pragma clang attribute pop'.
void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
                             const IdentifierInfo *Namespace);

/// Adds the attributes that have been specified using the
/// '\#pragma clang attribute push' directives to the given declaration.
void AddPragmaAttributes(Scope *S, Decl *D);

void DiagnoseUnterminatedPragmaAttribute();

/// Called on well formed \#pragma clang optimize.
void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);

/// Get the location for the currently active "\#pragma clang optimize
/// off". If this location is invalid, then the state of the pragma is "on".
SourceLocation getOptimizeOffPragmaLocation() const {
  return OptimizeOffPragmaLocation;
}

/// Only called on function definitions; if there is a pragma in scope
/// with the effect of a range-based optnone, consider marking the function
/// with attribute optnone.
void AddRangeBasedOptnone(FunctionDecl *FD);

/// Adds the 'optnone' attribute to the function declaration if there
/// are no conflicts; Loc represents the location causing the 'optnone'
/// attribute to be added (usually because of a pragma).
void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);

/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                    bool IsPackExpansion);
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, TypeSourceInfo *T,
                    bool IsPackExpansion);

/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
/// declaration.
void AddAssumeAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                          Expr *OE);

/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
/// declaration.
void AddAllocAlignAttr(Decl *D, const AttributeCommonInfo &CI,
                       Expr *ParamExpr);

/// AddAlignValueAttr - Adds an align_value attribute to a particular
/// declaration.
void AddAlignValueAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E);

/// AddAnnotationAttr - Adds an annotation Annot with Args arguments to D.
void AddAnnotationAttr(Decl *D, const AttributeCommonInfo &CI,
                       StringRef Annot, MutableArrayRef<Expr *> Args);

/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
/// declaration.
void AddLaunchBoundsAttr(Decl *D, const AttributeCommonInfo &CI,
                         Expr *MaxThreads, Expr *MinBlocks);

/// AddModeAttr - Adds a mode attribute to a particular declaration.
void AddModeAttr(Decl *D, const AttributeCommonInfo &CI, IdentifierInfo *Name,
                 bool InInstantiation = false);

void AddParameterABIAttr(Decl *D, const AttributeCommonInfo &CI,
                         ParameterABI ABI);

enum class RetainOwnershipKind {NS, CF, OS};
void AddXConsumedAttr(Decl *D, const AttributeCommonInfo &CI,
                      RetainOwnershipKind K, bool IsTemplateInstantiation);

/// addAMDGPUFlatWorkGroupSizeAttr - Adds an amdgpu_flat_work_group_size
/// attribute to a particular declaration.
void addAMDGPUFlatWorkGroupSizeAttr(Decl *D, const AttributeCommonInfo &CI,
                                    Expr *Min, Expr *Max);

/// addAMDGPUWavePersEUAttr - Adds an amdgpu_waves_per_eu attribute to a
/// particular declaration.
void addAMDGPUWavesPerEUAttr(Decl *D, const AttributeCommonInfo &CI,
                             Expr *Min, Expr *Max);

bool checkNSReturnsRetainedReturnType(SourceLocation loc, QualType type);

//===--------------------------------------------------------------------===//
// C++ Coroutines TS
//
bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
                             StringRef Keyword);
ExprResult ActOnCoawaitExpr(Scope *S, SourceLocation KwLoc, Expr *E);
ExprResult ActOnCoyieldExpr(Scope *S, SourceLocation KwLoc, Expr *E);
StmtResult ActOnCoreturnStmt(Scope *S, SourceLocation KwLoc, Expr *E);

ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                    bool IsImplicit = false);
ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                      UnresolvedLookupExpr* Lookup);
ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
                             bool IsImplicit = false);
StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
bool buildCoroutineParameterMoves(SourceLocation Loc);
VarDecl *buildCoroutinePromise(SourceLocation Loc);
void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
                                         SourceLocation FuncLoc);
/// Check that the expression co_await promise.final_suspend() shall not be
/// potentially-throwing.
bool checkFinalSuspendNoThrow(const Stmt *FinalSuspend);

//===--------------------------------------------------------------------===//
// OpenMP directives and clauses.
//
10220private:
void *VarDataSharingAttributesStack;

struct DeclareTargetContextInfo {
  struct MapInfo {
    OMPDeclareTargetDeclAttr::MapTypeTy MT;
    SourceLocation Loc;
  };
  /// Explicitly listed variables and functions in a 'to' or 'link' clause.
  llvm::DenseMap<NamedDecl *, MapInfo> ExplicitlyMapped;

  /// The 'device_type' as parsed from the clause.
  OMPDeclareTargetDeclAttr::DevTypeTy DT = OMPDeclareTargetDeclAttr::DT_Any;

  /// The directive kind, `begin declare target` or `declare target`.
  OpenMPDirectiveKind Kind;

  /// The directive location.
  SourceLocation Loc;

  DeclareTargetContextInfo(OpenMPDirectiveKind Kind, SourceLocation Loc)
      : Kind(Kind), Loc(Loc) {}
};

/// Number of nested '#pragma omp declare target' directives.
SmallVector<DeclareTargetContextInfo, 4> DeclareTargetNesting;

/// Initialization of data-sharing attributes stack.
void InitDataSharingAttributesStack();
void DestroyDataSharingAttributesStack();
ExprResult
VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
                                      bool StrictlyPositive = true,
                                      bool SuppressExprDiags = false);
/// Returns OpenMP nesting level for current directive.
unsigned getOpenMPNestingLevel() const;

/// Adjusts the function scopes index for the target-based regions.
void adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
                                  unsigned Level) const;

/// Returns the number of scopes associated with the construct on the given
/// OpenMP level.
int getNumberOfConstructScopes(unsigned Level) const;

/// Push new OpenMP function region for non-capturing function.
void pushOpenMPFunctionRegion();

/// Pop OpenMP function region for non-capturing function.
void popOpenMPFunctionRegion(const sema::FunctionScopeInfo *OldFSI);

/// Analyzes and checks a loop nest for use by a loop transformation.
///
/// \param Kind          The loop transformation directive kind.
/// \param NumLoops      How many nested loops the directive is expecting.
/// \param AStmt         Associated statement of the transformation directive.
/// \param LoopHelpers   [out] The loop analysis result.
/// \param Body          [out] The body code nested in \p NumLoops loop.
/// \param OriginalInits [out] Collection of statements and declarations that
///                      must have been executed/declared before entering the
///                      loop.
///
/// \return Whether there was any error.
bool checkTransformableLoopNest(
    OpenMPDirectiveKind Kind, Stmt *AStmt, int NumLoops,
    SmallVectorImpl<OMPLoopBasedDirective::HelperExprs> &LoopHelpers,
    Stmt *&Body,
    SmallVectorImpl<SmallVector<llvm::PointerUnion<Stmt *, Decl *>, 0>>
        &OriginalInits);

/// Helper to keep information about the current `omp begin/end declare
/// variant` nesting.
struct OMPDeclareVariantScope {
  /// The associated OpenMP context selector.
  OMPTraitInfo *TI;

  /// The associated OpenMP context selector mangling.
  std::string NameSuffix;

  OMPDeclareVariantScope(OMPTraitInfo &TI);
};

/// Return the OMPTraitInfo for the surrounding scope, if any.
OMPTraitInfo *getOMPTraitInfoForSurroundingScope() {
  return OMPDeclareVariantScopes.empty() ? nullptr
                                         : OMPDeclareVariantScopes.back().TI;
}

/// The current `omp begin/end declare variant` scopes.
SmallVector<OMPDeclareVariantScope, 4> OMPDeclareVariantScopes;

/// The current `omp begin/end assumes` scopes.
SmallVector<AssumptionAttr *, 4> OMPAssumeScoped;

/// All `omp assumes` we encountered so far.
SmallVector<AssumptionAttr *, 4> OMPAssumeGlobal;

10317public:
/// The declarator \p D defines a function in the scope \p S which is nested
/// in an `omp begin/end declare variant` scope. In this method we create a
/// declaration for \p D and rename \p D according to the OpenMP context
/// selector of the surrounding scope. Return all base functions in \p Bases.
void ActOnStartOfFunctionDefinitionInOpenMPDeclareVariantScope(
    Scope *S, Declarator &D, MultiTemplateParamsArg TemplateParameterLists,
    SmallVectorImpl<FunctionDecl *> &Bases);

/// Register \p D as specialization of all base functions in \p Bases in the
/// current `omp begin/end declare variant` scope.
void ActOnFinishedFunctionDefinitionInOpenMPDeclareVariantScope(
    Decl *D, SmallVectorImpl<FunctionDecl *> &Bases);

/// Act on \p D, a function definition inside of an `omp [begin/end] assumes`.
void ActOnFinishedFunctionDefinitionInOpenMPAssumeScope(Decl *D);

/// Can we exit an OpenMP declare variant scope at the moment.
bool isInOpenMPDeclareVariantScope() const {
  return !OMPDeclareVariantScopes.empty();
}

/// Given the potential call expression \p Call, determine if there is a
/// specialization via the OpenMP declare variant mechanism available. If
/// there is, return the specialized call expression, otherwise return the
/// original \p Call.
ExprResult ActOnOpenMPCall(ExprResult Call, Scope *Scope,
                           SourceLocation LParenLoc, MultiExprArg ArgExprs,
                           SourceLocation RParenLoc, Expr *ExecConfig);

/// Handle a `omp begin declare variant`.
void ActOnOpenMPBeginDeclareVariant(SourceLocation Loc, OMPTraitInfo &TI);

/// Handle a `omp end declare variant`.
void ActOnOpenMPEndDeclareVariant();

/// Checks if the variant/multiversion functions are compatible.
bool areMultiversionVariantFunctionsCompatible(
    const FunctionDecl *OldFD, const FunctionDecl *NewFD,
    const PartialDiagnostic &NoProtoDiagID,
    const PartialDiagnosticAt &NoteCausedDiagIDAt,
    const PartialDiagnosticAt &NoSupportDiagIDAt,
    const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
    bool ConstexprSupported, bool CLinkageMayDiffer);

/// Function tries to capture lambda's captured variables in the OpenMP region
/// before the original lambda is captured.
void tryCaptureOpenMPLambdas(ValueDecl *V);

/// Return true if the provided declaration \a VD should be captured by
/// reference.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
/// \param OpenMPCaptureLevel Capture level within an OpenMP construct.
bool isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level,
                           unsigned OpenMPCaptureLevel) const;

/// Check if the specified variable is used in one of the private
/// clauses (private, firstprivate, lastprivate, reduction etc.) in OpenMP
/// constructs.
VarDecl *isOpenMPCapturedDecl(ValueDecl *D, bool CheckScopeInfo = false,
                              unsigned StopAt = 0);
ExprResult getOpenMPCapturedExpr(VarDecl *Capture, ExprValueKind VK,
                                 ExprObjectKind OK, SourceLocation Loc);

/// If the current region is a loop-based region, mark the start of the loop
/// construct.
void startOpenMPLoop();

/// If the current region is a range loop-based region, mark the start of the
/// loop construct.
void startOpenMPCXXRangeFor();

/// Check if the specified variable is used in 'private' clause.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
OpenMPClauseKind isOpenMPPrivateDecl(ValueDecl *D, unsigned Level,
                                     unsigned CapLevel) const;

/// Sets OpenMP capture kind (OMPC_private, OMPC_firstprivate, OMPC_map etc.)
/// for \p FD based on DSA for the provided corresponding captured declaration
/// \p D.
void setOpenMPCaptureKind(FieldDecl *FD, const ValueDecl *D, unsigned Level);

/// Check if the specified variable is captured  by 'target' directive.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
bool isOpenMPTargetCapturedDecl(const ValueDecl *D, unsigned Level,
                                unsigned CaptureLevel) const;

/// Check if the specified global variable must be captured  by outer capture
/// regions.
/// \param Level Relative level of nested OpenMP construct for that
/// the check is performed.
bool isOpenMPGlobalCapturedDecl(ValueDecl *D, unsigned Level,
                                unsigned CaptureLevel) const;

ExprResult PerformOpenMPImplicitIntegerConversion(SourceLocation OpLoc,
                                                  Expr *Op);
/// Called on start of new data sharing attribute block.
void StartOpenMPDSABlock(OpenMPDirectiveKind K,
                         const DeclarationNameInfo &DirName, Scope *CurScope,
                         SourceLocation Loc);
/// Start analysis of clauses.
void StartOpenMPClause(OpenMPClauseKind K);
/// End analysis of clauses.
void EndOpenMPClause();
/// Called on end of data sharing attribute block.
void EndOpenMPDSABlock(Stmt *CurDirective);

/// Check if the current region is an OpenMP loop region and if it is,
/// mark loop control variable, used in \p Init for loop initialization, as
/// private by default.
/// \param Init First part of the for loop.
void ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init);

// OpenMP directives and clauses.
/// Called on correct id-expression from the '#pragma omp
/// threadprivate'.
ExprResult ActOnOpenMPIdExpression(Scope *CurScope, CXXScopeSpec &ScopeSpec,
                                   const DeclarationNameInfo &Id,
                                   OpenMPDirectiveKind Kind);
/// Called on well-formed '#pragma omp threadprivate'.
DeclGroupPtrTy ActOnOpenMPThreadprivateDirective(
                                   SourceLocation Loc,
                                   ArrayRef<Expr *> VarList);
/// Builds a new OpenMPThreadPrivateDecl and checks its correctness.
OMPThreadPrivateDecl *CheckOMPThreadPrivateDecl(SourceLocation Loc,
                                                ArrayRef<Expr *> VarList);
/// Called on well-formed '#pragma omp allocate'.
DeclGroupPtrTy ActOnOpenMPAllocateDirective(SourceLocation Loc,
                                            ArrayRef<Expr *> VarList,
                                            ArrayRef<OMPClause *> Clauses,
                                            DeclContext *Owner = nullptr);

/// Called on well-formed '#pragma omp [begin] assume[s]'.
void ActOnOpenMPAssumesDirective(SourceLocation Loc,
                                 OpenMPDirectiveKind DKind,
                                 ArrayRef<StringRef> Assumptions,
                                 bool SkippedClauses);

/// Check if there is an active global `omp begin assumes` directive.
bool isInOpenMPAssumeScope() const { return !OMPAssumeScoped.empty(); }

/// Check if there is an active global `omp assumes` directive.
bool hasGlobalOpenMPAssumes() const { return !OMPAssumeGlobal.empty(); }

/// Called on well-formed '#pragma omp end assumes'.
void ActOnOpenMPEndAssumesDirective();

/// Called on well-formed '#pragma omp requires'.
DeclGroupPtrTy ActOnOpenMPRequiresDirective(SourceLocation Loc,
                                            ArrayRef<OMPClause *> ClauseList);
/// Check restrictions on Requires directive
OMPRequiresDecl *CheckOMPRequiresDecl(SourceLocation Loc,
                                      ArrayRef<OMPClause *> Clauses);
/// Check if the specified type is allowed to be used in 'omp declare
/// reduction' construct.
QualType ActOnOpenMPDeclareReductionType(SourceLocation TyLoc,
                                         TypeResult ParsedType);
/// Called on start of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveStart(
    Scope *S, DeclContext *DC, DeclarationName Name,
    ArrayRef<std::pair<QualType, SourceLocation>> ReductionTypes,
    AccessSpecifier AS, Decl *PrevDeclInScope = nullptr);
/// Initialize declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerEnd(Decl *D, Expr *Combiner);
/// Initialize declare reduction construct initializer.
/// \return omp_priv variable.
VarDecl *ActOnOpenMPDeclareReductionInitializerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionInitializerEnd(Decl *D, Expr *Initializer,
                                               VarDecl *OmpPrivParm);
/// Called at the end of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveEnd(
    Scope *S, DeclGroupPtrTy DeclReductions, bool IsValid);

/// Check variable declaration in 'omp declare mapper' construct.
TypeResult ActOnOpenMPDeclareMapperVarDecl(Scope *S, Declarator &D);
/// Check if the specified type is allowed to be used in 'omp declare
/// mapper' construct.
QualType ActOnOpenMPDeclareMapperType(SourceLocation TyLoc,
                                      TypeResult ParsedType);
/// Called on start of '#pragma omp declare mapper'.
DeclGroupPtrTy ActOnOpenMPDeclareMapperDirective(
    Scope *S, DeclContext *DC, DeclarationName Name, QualType MapperType,
    SourceLocation StartLoc, DeclarationName VN, AccessSpecifier AS,
    Expr *MapperVarRef, ArrayRef<OMPClause *> Clauses,
    Decl *PrevDeclInScope = nullptr);
/// Build the mapper variable of '#pragma omp declare mapper'.
ExprResult ActOnOpenMPDeclareMapperDirectiveVarDecl(Scope *S,
                                                    QualType MapperType,
                                                    SourceLocation StartLoc,
                                                    DeclarationName VN);
bool isOpenMPDeclareMapperVarDeclAllowed(const VarDecl *VD) const;
const ValueDecl *getOpenMPDeclareMapperVarName() const;

/// Called on the start of target region i.e. '#pragma omp declare target'.
bool ActOnStartOpenMPDeclareTargetContext(DeclareTargetContextInfo &DTCI);

/// Called at the end of target region i.e. '#pragma omp end declare target'.
const DeclareTargetContextInfo ActOnOpenMPEndDeclareTargetDirective();

/// Called once a target context is completed, that can be when a
/// '#pragma omp end declare target' was encountered or when a
/// '#pragma omp declare target' without declaration-definition-seq was
/// encountered.
void ActOnFinishedOpenMPDeclareTargetContext(DeclareTargetContextInfo &DTCI);

/// Searches for the provided declaration name for OpenMP declare target
/// directive.
NamedDecl *lookupOpenMPDeclareTargetName(Scope *CurScope,
                                         CXXScopeSpec &ScopeSpec,
                                         const DeclarationNameInfo &Id);

/// Called on correct id-expression from the '#pragma omp declare target'.
void ActOnOpenMPDeclareTargetName(NamedDecl *ND, SourceLocation Loc,
                                  OMPDeclareTargetDeclAttr::MapTypeTy MT,
                                  OMPDeclareTargetDeclAttr::DevTypeTy DT);

/// Check declaration inside target region.
void
checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D,
                                 SourceLocation IdLoc = SourceLocation());
/// Finishes analysis of the deferred functions calls that may be declared as
/// host/nohost during device/host compilation.
void finalizeOpenMPDelayedAnalysis(const FunctionDecl *Caller,
                                   const FunctionDecl *Callee,
                                   SourceLocation Loc);
/// Return true inside OpenMP declare target region.
bool isInOpenMPDeclareTargetContext() const {
  return !DeclareTargetNesting.empty();
}
/// Return true inside OpenMP target region.
bool isInOpenMPTargetExecutionDirective() const;

/// Return the number of captured regions created for an OpenMP directive.
static int getOpenMPCaptureLevels(OpenMPDirectiveKind Kind);

/// Initialization of captured region for OpenMP region.
void ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope);

/// Called for syntactical loops (ForStmt or CXXForRangeStmt) associated to
/// an OpenMP loop directive.
StmtResult ActOnOpenMPCanonicalLoop(Stmt *AStmt);

/// End of OpenMP region.
///
/// \param S Statement associated with the current OpenMP region.
/// \param Clauses List of clauses for the current OpenMP region.
///
/// \returns Statement for finished OpenMP region.
StmtResult ActOnOpenMPRegionEnd(StmtResult S, ArrayRef<OMPClause *> Clauses);
StmtResult ActOnOpenMPExecutableDirective(
    OpenMPDirectiveKind Kind, const DeclarationNameInfo &DirName,
    OpenMPDirectiveKind CancelRegion, ArrayRef<OMPClause *> Clauses,
    Stmt *AStmt, SourceLocation StartLoc, SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt,
                                        SourceLocation StartLoc,
                                        SourceLocation EndLoc);
using VarsWithInheritedDSAType =
    llvm::SmallDenseMap<const ValueDecl *, const Expr *, 4>;
/// Called on well-formed '\#pragma omp simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                         SourceLocation StartLoc, SourceLocation EndLoc,
                         VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '#pragma omp tile' after parsing of its clauses and
/// the associated statement.
StmtResult ActOnOpenMPTileDirective(ArrayRef<OMPClause *> Clauses,
                                    Stmt *AStmt, SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '#pragma omp unroll' after parsing of its clauses
/// and the associated statement.
StmtResult ActOnOpenMPUnrollDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp for' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                        SourceLocation StartLoc, SourceLocation EndLoc,
                        VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp for simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                            SourceLocation StartLoc, SourceLocation EndLoc,
                            VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp sections' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp section' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSectionDirective(Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp single' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSingleDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp master' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterDirective(Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp critical' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPCriticalDirective(const DeclarationNameInfo &DirName,
                                        ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel for' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel for simd' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelMasterDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel sections' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                                Stmt *AStmt,
                                                SourceLocation StartLoc,
                                                SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp task' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTaskDirective(ArrayRef<OMPClause *> Clauses,
                                    Stmt *AStmt, SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskyield'.
StmtResult ActOnOpenMPTaskyieldDirective(SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp barrier'.
StmtResult ActOnOpenMPBarrierDirective(SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskwait'.
StmtResult ActOnOpenMPTaskwaitDirective(SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskgroup'.
StmtResult ActOnOpenMPTaskgroupDirective(ArrayRef<OMPClause *> Clauses,
                                         Stmt *AStmt, SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp flush'.
StmtResult ActOnOpenMPFlushDirective(ArrayRef<OMPClause *> Clauses,
                                     SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp depobj'.
StmtResult ActOnOpenMPDepobjDirective(ArrayRef<OMPClause *> Clauses,
                                      SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp scan'.
StmtResult ActOnOpenMPScanDirective(ArrayRef<OMPClause *> Clauses,
                                    SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp ordered' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
                                       Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp atomic' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target data' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTargetDataDirective(ArrayRef<OMPClause *> Clauses,
                                          Stmt *AStmt, SourceLocation StartLoc,
                                          SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target enter data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetEnterDataDirective(ArrayRef<OMPClause *> Clauses,
                                               SourceLocation StartLoc,
                                               SourceLocation EndLoc,
                                               Stmt *AStmt);
/// Called on well-formed '\#pragma omp target exit data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetExitDataDirective(ArrayRef<OMPClause *> Clauses,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc,
                                              Stmt *AStmt);
/// Called on well-formed '\#pragma omp target parallel' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target parallel for' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPTargetParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                     Stmt *AStmt, SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp cancellation point'.
StmtResult
ActOnOpenMPCancellationPointDirective(SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp cancel'.
StmtResult ActOnOpenMPCancelDirective(ArrayRef<OMPClause *> Clauses,
                                      SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp taskloop' after parsing of the
/// associated statement.
StmtResult
ActOnOpenMPTaskLoopDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                             SourceLocation StartLoc, SourceLocation EndLoc,
                             VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp taskloop simd' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp master taskloop' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp master taskloop simd' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPMasterTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master taskloop' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPParallelMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master taskloop simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPParallelMasterTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPDistributeDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target update'.
StmtResult ActOnOpenMPTargetUpdateDirective(ArrayRef<OMPClause *> Clauses,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc,
                                            Stmt *AStmt);
/// Called on well-formed '\#pragma omp distribute parallel for' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target parallel for simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target simd' after parsing of
/// the associated statement.
StmtResult
ActOnOpenMPTargetSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute simd' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                           Stmt *AStmt,
                                           SourceLocation StartLoc,
                                           SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target teams distribute' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for
/// simd' after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp interop'.
StmtResult ActOnOpenMPInteropDirective(ArrayRef<OMPClause *> Clauses,
                                       SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp dispatch' after parsing of the
// /associated statement.
StmtResult ActOnOpenMPDispatchDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp masked' after parsing of the
// /associated statement.
StmtResult ActOnOpenMPMaskedDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);

/// Checks correctness of linear modifiers.
bool CheckOpenMPLinearModifier(OpenMPLinearClauseKind LinKind,
                               SourceLocation LinLoc);
/// Checks that the specified declaration matches requirements for the linear
/// decls.
bool CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
                           OpenMPLinearClauseKind LinKind, QualType Type,
                           bool IsDeclareSimd = false);

/// Called on well-formed '\#pragma omp declare simd' after parsing of
/// the associated method/function.
DeclGroupPtrTy ActOnOpenMPDeclareSimdDirective(
    DeclGroupPtrTy DG, OMPDeclareSimdDeclAttr::BranchStateTy BS,
    Expr *Simdlen, ArrayRef<Expr *> Uniforms, ArrayRef<Expr *> Aligneds,
    ArrayRef<Expr *> Alignments, ArrayRef<Expr *> Linears,
    ArrayRef<unsigned> LinModifiers, ArrayRef<Expr *> Steps, SourceRange SR);

/// Checks '\#pragma omp declare variant' variant function and original
/// functions after parsing of the associated method/function.
/// \param DG Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \param TI The trait info object representing the match clause.
/// \returns None, if the function/variant function are not compatible with
/// the pragma, pair of original function/variant ref expression otherwise.
Optional<std::pair<FunctionDecl *, Expr *>>
checkOpenMPDeclareVariantFunction(DeclGroupPtrTy DG, Expr *VariantRef,
                                  OMPTraitInfo &TI, SourceRange SR);

/// Called on well-formed '\#pragma omp declare variant' after parsing of
/// the associated method/function.
/// \param FD Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \param TI The context traits associated with the function variant.
void ActOnOpenMPDeclareVariantDirective(FunctionDecl *FD, Expr *VariantRef,
                                        OMPTraitInfo &TI, SourceRange SR);

OMPClause *ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind,
                                       Expr *Expr,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'allocator' clause.
OMPClause *ActOnOpenMPAllocatorClause(Expr *Allocator,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'if' clause.
OMPClause *ActOnOpenMPIfClause(OpenMPDirectiveKind NameModifier,
                               Expr *Condition, SourceLocation StartLoc,
                               SourceLocation LParenLoc,
                               SourceLocation NameModifierLoc,
                               SourceLocation ColonLoc,
                               SourceLocation EndLoc);
/// Called on well-formed 'final' clause.
OMPClause *ActOnOpenMPFinalClause(Expr *Condition, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'num_threads' clause.
OMPClause *ActOnOpenMPNumThreadsClause(Expr *NumThreads,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'safelen' clause.
OMPClause *ActOnOpenMPSafelenClause(Expr *Length,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simdlen' clause.
OMPClause *ActOnOpenMPSimdlenClause(Expr *Length, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-form 'sizes' clause.
OMPClause *ActOnOpenMPSizesClause(ArrayRef<Expr *> SizeExprs,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-form 'full' clauses.
OMPClause *ActOnOpenMPFullClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-form 'partial' clauses.
OMPClause *ActOnOpenMPPartialClause(Expr *FactorExpr, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'collapse' clause.
OMPClause *ActOnOpenMPCollapseClause(Expr *NumForLoops,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'ordered' clause.
OMPClause *
ActOnOpenMPOrderedClause(SourceLocation StartLoc, SourceLocation EndLoc,
                         SourceLocation LParenLoc = SourceLocation(),
                         Expr *NumForLoops = nullptr);
/// Called on well-formed 'grainsize' clause.
OMPClause *ActOnOpenMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'num_tasks' clause.
OMPClause *ActOnOpenMPNumTasksClause(Expr *NumTasks, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'hint' clause.
OMPClause *ActOnOpenMPHintClause(Expr *Hint, SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'detach' clause.
OMPClause *ActOnOpenMPDetachClause(Expr *Evt, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);

OMPClause *ActOnOpenMPSimpleClause(OpenMPClauseKind Kind,
                                   unsigned Argument,
                                   SourceLocation ArgumentLoc,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'default' clause.
OMPClause *ActOnOpenMPDefaultClause(llvm::omp::DefaultKind Kind,
                                    SourceLocation KindLoc,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'proc_bind' clause.
OMPClause *ActOnOpenMPProcBindClause(llvm::omp::ProcBindKind Kind,
                                     SourceLocation KindLoc,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'order' clause.
OMPClause *ActOnOpenMPOrderClause(OpenMPOrderClauseKind Kind,
                                  SourceLocation KindLoc,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'update' clause.
OMPClause *ActOnOpenMPUpdateClause(OpenMPDependClauseKind Kind,
                                   SourceLocation KindLoc,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);

OMPClause *ActOnOpenMPSingleExprWithArgClause(
    OpenMPClauseKind Kind, ArrayRef<unsigned> Arguments, Expr *Expr,
    SourceLocation StartLoc, SourceLocation LParenLoc,
    ArrayRef<SourceLocation> ArgumentsLoc, SourceLocation DelimLoc,
    SourceLocation EndLoc);
/// Called on well-formed 'schedule' clause.
OMPClause *ActOnOpenMPScheduleClause(
    OpenMPScheduleClauseModifier M1, OpenMPScheduleClauseModifier M2,
    OpenMPScheduleClauseKind Kind, Expr *ChunkSize, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation M1Loc, SourceLocation M2Loc,
    SourceLocation KindLoc, SourceLocation CommaLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPClause(OpenMPClauseKind Kind, SourceLocation StartLoc,
                             SourceLocation EndLoc);
/// Called on well-formed 'nowait' clause.
OMPClause *ActOnOpenMPNowaitClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'untied' clause.
OMPClause *ActOnOpenMPUntiedClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'mergeable' clause.
OMPClause *ActOnOpenMPMergeableClause(SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'read' clause.
OMPClause *ActOnOpenMPReadClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'write' clause.
OMPClause *ActOnOpenMPWriteClause(SourceLocation StartLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'update' clause.
OMPClause *ActOnOpenMPUpdateClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'capture' clause.
OMPClause *ActOnOpenMPCaptureClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'seq_cst' clause.
OMPClause *ActOnOpenMPSeqCstClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'acq_rel' clause.
OMPClause *ActOnOpenMPAcqRelClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'acquire' clause.
OMPClause *ActOnOpenMPAcquireClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'release' clause.
OMPClause *ActOnOpenMPReleaseClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'relaxed' clause.
OMPClause *ActOnOpenMPRelaxedClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);

/// Called on well-formed 'init' clause.
OMPClause *ActOnOpenMPInitClause(Expr *InteropVar, ArrayRef<Expr *> PrefExprs,
                                 bool IsTarget, bool IsTargetSync,
                                 SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation VarLoc,
                                 SourceLocation EndLoc);

/// Called on well-formed 'use' clause.
OMPClause *ActOnOpenMPUseClause(Expr *InteropVar, SourceLocation StartLoc,
                                SourceLocation LParenLoc,
                                SourceLocation VarLoc, SourceLocation EndLoc);

/// Called on well-formed 'destroy' clause.
OMPClause *ActOnOpenMPDestroyClause(Expr *InteropVar, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation VarLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'novariants' clause.
OMPClause *ActOnOpenMPNovariantsClause(Expr *Condition,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'nocontext' clause.
OMPClause *ActOnOpenMPNocontextClause(Expr *Condition,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'filter' clause.
OMPClause *ActOnOpenMPFilterClause(Expr *ThreadID, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'threads' clause.
OMPClause *ActOnOpenMPThreadsClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simd' clause.
OMPClause *ActOnOpenMPSIMDClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'nogroup' clause.
OMPClause *ActOnOpenMPNogroupClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
                                                SourceLocation EndLoc);

/// Called on well-formed 'reverse_offload' clause.
OMPClause *ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'dynamic_allocators' clause.
OMPClause *ActOnOpenMPDynamicAllocatorsClause(SourceLocation StartLoc,
                                              SourceLocation EndLoc);

/// Called on well-formed 'atomic_default_mem_order' clause.
OMPClause *ActOnOpenMPAtomicDefaultMemOrderClause(
    OpenMPAtomicDefaultMemOrderClauseKind Kind, SourceLocation KindLoc,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPVarListClause(
    OpenMPClauseKind Kind, ArrayRef<Expr *> Vars, Expr *DepModOrTailExpr,
    const OMPVarListLocTy &Locs, SourceLocation ColonLoc,
    CXXScopeSpec &ReductionOrMapperIdScopeSpec,
    DeclarationNameInfo &ReductionOrMapperId, int ExtraModifier,
    ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
    ArrayRef<SourceLocation> MapTypeModifiersLoc, bool IsMapTypeImplicit,
    SourceLocation ExtraModifierLoc,
    ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
    ArrayRef<SourceLocation> MotionModifiersLoc);
/// Called on well-formed 'inclusive' clause.
OMPClause *ActOnOpenMPInclusiveClause(ArrayRef<Expr *> VarList,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'exclusive' clause.
OMPClause *ActOnOpenMPExclusiveClause(ArrayRef<Expr *> VarList,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'allocate' clause.
OMPClause *
ActOnOpenMPAllocateClause(Expr *Allocator, ArrayRef<Expr *> VarList,
                          SourceLocation StartLoc, SourceLocation ColonLoc,
                          SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'private' clause.
OMPClause *ActOnOpenMPPrivateClause(ArrayRef<Expr *> VarList,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'firstprivate' clause.
OMPClause *ActOnOpenMPFirstprivateClause(ArrayRef<Expr *> VarList,
                                         SourceLocation StartLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed 'lastprivate' clause.
OMPClause *ActOnOpenMPLastprivateClause(
    ArrayRef<Expr *> VarList, OpenMPLastprivateModifier LPKind,
    SourceLocation LPKindLoc, SourceLocation ColonLoc,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'shared' clause.
OMPClause *ActOnOpenMPSharedClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'reduction' clause.
OMPClause *ActOnOpenMPReductionClause(
    ArrayRef<Expr *> VarList, OpenMPReductionClauseModifier Modifier,
    SourceLocation StartLoc, SourceLocation LParenLoc,
    SourceLocation ModifierLoc, SourceLocation ColonLoc,
    SourceLocation EndLoc, CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'task_reduction' clause.
OMPClause *ActOnOpenMPTaskReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'in_reduction' clause.
OMPClause *ActOnOpenMPInReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'linear' clause.
OMPClause *
ActOnOpenMPLinearClause(ArrayRef<Expr *> VarList, Expr *Step,
                        SourceLocation StartLoc, SourceLocation LParenLoc,
                        OpenMPLinearClauseKind LinKind, SourceLocation LinLoc,
                        SourceLocation ColonLoc, SourceLocation EndLoc);
/// Called on well-formed 'aligned' clause.
OMPClause *ActOnOpenMPAlignedClause(ArrayRef<Expr *> VarList,
                                    Expr *Alignment,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation ColonLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'copyin' clause.
OMPClause *ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'copyprivate' clause.
OMPClause *ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'flush' pseudo clause.
OMPClause *ActOnOpenMPFlushClause(ArrayRef<Expr *> VarList,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'depobj' pseudo clause.
OMPClause *ActOnOpenMPDepobjClause(Expr *Depobj, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'depend' clause.
OMPClause *
ActOnOpenMPDependClause(Expr *DepModifier, OpenMPDependClauseKind DepKind,
                        SourceLocation DepLoc, SourceLocation ColonLoc,
                        ArrayRef<Expr *> VarList, SourceLocation StartLoc,
                        SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'device' clause.
OMPClause *ActOnOpenMPDeviceClause(OpenMPDeviceClauseModifier Modifier,
                                   Expr *Device, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation ModifierLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'map' clause.
OMPClause *
ActOnOpenMPMapClause(ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
                     ArrayRef<SourceLocation> MapTypeModifiersLoc,
                     CXXScopeSpec &MapperIdScopeSpec,
                     DeclarationNameInfo &MapperId,
                     OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
                     SourceLocation MapLoc, SourceLocation ColonLoc,
                     ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                     ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'num_teams' clause.
OMPClause *ActOnOpenMPNumTeamsClause(Expr *NumTeams, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'thread_limit' clause.
OMPClause *ActOnOpenMPThreadLimitClause(Expr *ThreadLimit,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'priority' clause.
OMPClause *ActOnOpenMPPriorityClause(Expr *Priority, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'dist_schedule' clause.
OMPClause *ActOnOpenMPDistScheduleClause(
    OpenMPDistScheduleClauseKind Kind, Expr *ChunkSize,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation KindLoc,
    SourceLocation CommaLoc, SourceLocation EndLoc);
/// Called on well-formed 'defaultmap' clause.
OMPClause *ActOnOpenMPDefaultmapClause(
    OpenMPDefaultmapClauseModifier M, OpenMPDefaultmapClauseKind Kind,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation MLoc,
    SourceLocation KindLoc, SourceLocation EndLoc);
/// Called on well-formed 'to' clause.
OMPClause *
ActOnOpenMPToClause(ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
                    ArrayRef<SourceLocation> MotionModifiersLoc,
                    CXXScopeSpec &MapperIdScopeSpec,
                    DeclarationNameInfo &MapperId, SourceLocation ColonLoc,
                    ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                    ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'from' clause.
OMPClause *
ActOnOpenMPFromClause(ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
                      ArrayRef<SourceLocation> MotionModifiersLoc,
                      CXXScopeSpec &MapperIdScopeSpec,
                      DeclarationNameInfo &MapperId, SourceLocation ColonLoc,
                      ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                      ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'use_device_ptr' clause.
OMPClause *ActOnOpenMPUseDevicePtrClause(ArrayRef<Expr *> VarList,
                                         const OMPVarListLocTy &Locs);
/// Called on well-formed 'use_device_addr' clause.
OMPClause *ActOnOpenMPUseDeviceAddrClause(ArrayRef<Expr *> VarList,
                                          const OMPVarListLocTy &Locs);
/// Called on well-formed 'is_device_ptr' clause.
OMPClause *ActOnOpenMPIsDevicePtrClause(ArrayRef<Expr *> VarList,
                                        const OMPVarListLocTy &Locs);
/// Called on well-formed 'nontemporal' clause.
OMPClause *ActOnOpenMPNontemporalClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);

/// Data for list of allocators.
struct UsesAllocatorsData {
  /// Allocator.
  Expr *Allocator = nullptr;
  /// Allocator traits.
  Expr *AllocatorTraits = nullptr;
  /// Locations of '(' and ')' symbols.
  SourceLocation LParenLoc, RParenLoc;
};
/// Called on well-formed 'uses_allocators' clause.
OMPClause *ActOnOpenMPUsesAllocatorClause(SourceLocation StartLoc,
                                          SourceLocation LParenLoc,
                                          SourceLocation EndLoc,
                                          ArrayRef<UsesAllocatorsData> Data);
/// Called on well-formed 'affinity' clause.
OMPClause *ActOnOpenMPAffinityClause(SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation ColonLoc,
                                     SourceLocation EndLoc, Expr *Modifier,
                                     ArrayRef<Expr *> Locators);

/// The kind of conversion being performed.
enum CheckedConversionKind {
  /// An implicit conversion.
  CCK_ImplicitConversion,
  /// A C-style cast.
  CCK_CStyleCast,
  /// A functional-style cast.
  CCK_FunctionalCast,
  /// A cast other than a C-style cast.
  CCK_OtherCast,
  /// A conversion for an operand of a builtin overloaded operator.
  CCK_ForBuiltinOverloadedOp
};

static bool isCast(CheckedConversionKind CCK) {
  return CCK == CCK_CStyleCast || CCK == CCK_FunctionalCast ||
         CCK == CCK_OtherCast;
}

/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
/// cast.  If there is already an implicit cast, merge into the existing one.
/// If isLvalue, the result of the cast is an lvalue.
ExprResult
ImpCastExprToType(Expr *E, QualType Type, CastKind CK,
                  ExprValueKind VK = VK_PRValue,
                  const CXXCastPath *BasePath = nullptr,
                  CheckedConversionKind CCK = CCK_ImplicitConversion);

/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
/// to the conversion from scalar type ScalarTy to the Boolean type.
static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);

/// IgnoredValueConversions - Given that an expression's result is
/// syntactically ignored, perform any conversions that are
/// required.
ExprResult IgnoredValueConversions(Expr *E);

// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2) and converts
// functions and arrays to their respective pointers (C99 6.3.2.1).
ExprResult UsualUnaryConversions(Expr *E);

/// CallExprUnaryConversions - a special case of an unary conversion
/// performed on a function designator of a call expression.
ExprResult CallExprUnaryConversions(Expr *E);

// DefaultFunctionArrayConversion - converts functions and arrays
// to their respective pointers (C99 6.3.2.1).
ExprResult DefaultFunctionArrayConversion(Expr *E, bool Diagnose = true);

// DefaultFunctionArrayLvalueConversion - converts functions and
// arrays to their respective pointers and performs the
// lvalue-to-rvalue conversion.
ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
                                                bool Diagnose = true);

// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
// the operand. This function is a no-op if the operand has a function type
// or an array type.
ExprResult DefaultLvalueConversion(Expr *E);

// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
// do not have a prototype. Integer promotions are performed on each
// argument, and arguments that have type float are promoted to double.
ExprResult DefaultArgumentPromotion(Expr *E);

/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
/// it as an xvalue. In C++98, the result will still be a prvalue, because
/// we don't have xvalues there.
ExprResult TemporaryMaterializationConversion(Expr *E);

// Used for emitting the right warning by DefaultVariadicArgumentPromotion
enum VariadicCallType {
  VariadicFunction,
  VariadicBlock,
  VariadicMethod,
  VariadicConstructor,
  VariadicDoesNotApply
};

VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
                                     const FunctionProtoType *Proto,
                                     Expr *Fn);

// Used for determining in which context a type is allowed to be passed to a
// vararg function.
enum VarArgKind {
  VAK_Valid,
  VAK_ValidInCXX11,
  VAK_Undefined,
  VAK_MSVCUndefined,
  VAK_Invalid
};

// Determines which VarArgKind fits an expression.
VarArgKind isValidVarArgType(const QualType &Ty);

/// Check to see if the given expression is a valid argument to a variadic
/// function, issuing a diagnostic if not.
void checkVariadicArgument(const Expr *E, VariadicCallType CT);

/// Check whether the given statement can have musttail applied to it,
/// issuing a diagnostic and returning false if not. In the success case,
/// the statement is rewritten to remove implicit nodes from the return
/// value.
bool checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA);

11435private:
/// Check whether the given statement can have musttail applied to it,
/// issuing a diagnostic and returning false if not.
bool checkMustTailAttr(const Stmt *St, const Attr &MTA);

11440public:
/// Check to see if a given expression could have '.c_str()' called on it.
bool hasCStrMethod(const Expr *E);

/// GatherArgumentsForCall - Collector argument expressions for various
/// form of call prototypes.
bool GatherArgumentsForCall(SourceLocation CallLoc, FunctionDecl *FDecl,
                            const FunctionProtoType *Proto,
                            unsigned FirstParam, ArrayRef<Expr *> Args,
                            SmallVectorImpl<Expr *> &AllArgs,
                            VariadicCallType CallType = VariadicDoesNotApply,
                            bool AllowExplicit = false,
                            bool IsListInitialization = false);

// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
// will create a runtime trap if the resulting type is not a POD type.
ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
                                            FunctionDecl *FDecl);

/// Context in which we're performing a usual arithmetic conversion.
enum ArithConvKind {
  /// An arithmetic operation.
  ACK_Arithmetic,
  /// A bitwise operation.
  ACK_BitwiseOp,
  /// A comparison.
  ACK_Comparison,
  /// A conditional (?:) operator.
  ACK_Conditional,
  /// A compound assignment expression.
  ACK_CompAssign,
};

// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
// operands and then handles various conversions that are common to binary
// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
// routine returns the first non-arithmetic type found. The client is
// responsible for emitting appropriate error diagnostics.
QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc, ArithConvKind ACK);

/// AssignConvertType - All of the 'assignment' semantic checks return this
/// enum to indicate whether the assignment was allowed.  These checks are
/// done for simple assignments, as well as initialization, return from
/// function, argument passing, etc.  The query is phrased in terms of a
/// source and destination type.
enum AssignConvertType {
  /// Compatible - the types are compatible according to the standard.
  Compatible,

  /// PointerToInt - The assignment converts a pointer to an int, which we
  /// accept as an extension.
  PointerToInt,

  /// IntToPointer - The assignment converts an int to a pointer, which we
  /// accept as an extension.
  IntToPointer,

  /// FunctionVoidPointer - The assignment is between a function pointer and
  /// void*, which the standard doesn't allow, but we accept as an extension.
  FunctionVoidPointer,

  /// IncompatiblePointer - The assignment is between two pointers types that
  /// are not compatible, but we accept them as an extension.
  IncompatiblePointer,

  /// IncompatibleFunctionPointer - The assignment is between two function
  /// pointers types that are not compatible, but we accept them as an
  /// extension.
  IncompatibleFunctionPointer,

  /// IncompatiblePointerSign - The assignment is between two pointers types
  /// which point to integers which have a different sign, but are otherwise
  /// identical. This is a subset of the above, but broken out because it's by
  /// far the most common case of incompatible pointers.
  IncompatiblePointerSign,

  /// CompatiblePointerDiscardsQualifiers - The assignment discards
  /// c/v/r qualifiers, which we accept as an extension.
  CompatiblePointerDiscardsQualifiers,

  /// IncompatiblePointerDiscardsQualifiers - The assignment
  /// discards qualifiers that we don't permit to be discarded,
  /// like address spaces.
  IncompatiblePointerDiscardsQualifiers,

  /// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
  /// changes address spaces in nested pointer types which is not allowed.
  /// For instance, converting __private int ** to __generic int ** is
  /// illegal even though __private could be converted to __generic.
  IncompatibleNestedPointerAddressSpaceMismatch,

  /// IncompatibleNestedPointerQualifiers - The assignment is between two
  /// nested pointer types, and the qualifiers other than the first two
  /// levels differ e.g. char ** -> const char **, but we accept them as an
  /// extension.
  IncompatibleNestedPointerQualifiers,

  /// IncompatibleVectors - The assignment is between two vector types that
  /// have the same size, which we accept as an extension.
  IncompatibleVectors,

  /// IntToBlockPointer - The assignment converts an int to a block
  /// pointer. We disallow this.
  IntToBlockPointer,

  /// IncompatibleBlockPointer - The assignment is between two block
  /// pointers types that are not compatible.
  IncompatibleBlockPointer,

  /// IncompatibleObjCQualifiedId - The assignment is between a qualified
  /// id type and something else (that is incompatible with it). For example,
  /// "id <XXX>" = "Foo *", where "Foo *" doesn't implement the XXX protocol.
  IncompatibleObjCQualifiedId,

  /// IncompatibleObjCWeakRef - Assigning a weak-unavailable object to an
  /// object with __weak qualifier.
  IncompatibleObjCWeakRef,

  /// Incompatible - We reject this conversion outright, it is invalid to
  /// represent it in the AST.
  Incompatible
};

/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
/// assignment conversion type specified by ConvTy.  This returns true if the
/// conversion was invalid or false if the conversion was accepted.
bool DiagnoseAssignmentResult(AssignConvertType ConvTy,
                              SourceLocation Loc,
                              QualType DstType, QualType SrcType,
                              Expr *SrcExpr, AssignmentAction Action,
                              bool *Complained = nullptr);

/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
/// enum. If AllowMask is true, then we also allow the complement of a valid
/// value, to be used as a mask.
bool IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
                       bool AllowMask) const;

/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
/// integer not in the range of enum values.
void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
                            Expr *SrcExpr);

/// CheckAssignmentConstraints - Perform type checking for assignment,
/// argument passing, variable initialization, and function return values.
/// C99 6.5.16.
AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
                                             QualType LHSType,
                                             QualType RHSType);

/// Check assignment constraints and optionally prepare for a conversion of
/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
/// is true.
AssignConvertType CheckAssignmentConstraints(QualType LHSType,
                                             ExprResult &RHS,
                                             CastKind &Kind,
                                             bool ConvertRHS = true);

/// Check assignment constraints for an assignment of RHS to LHSType.
///
/// \param LHSType The destination type for the assignment.
/// \param RHS The source expression for the assignment.
/// \param Diagnose If \c true, diagnostics may be produced when checking
///        for assignability. If a diagnostic is produced, \p RHS will be
///        set to ExprError(). Note that this function may still return
///        without producing a diagnostic, even for an invalid assignment.
/// \param DiagnoseCFAudited If \c true, the target is a function parameter
///        in an audited Core Foundation API and does not need to be checked
///        for ARC retain issues.
/// \param ConvertRHS If \c true, \p RHS will be updated to model the
///        conversions necessary to perform the assignment. If \c false,
///        \p Diagnose must also be \c false.
AssignConvertType CheckSingleAssignmentConstraints(
    QualType LHSType, ExprResult &RHS, bool Diagnose = true,
    bool DiagnoseCFAudited = false, bool ConvertRHS = true);

// If the lhs type is a transparent union, check whether we
// can initialize the transparent union with the given expression.
AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
                                                           ExprResult &RHS);

bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);

bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);

ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     AssignmentAction Action,
                                     bool AllowExplicit = false);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const ImplicitConversionSequence& ICS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK
                                        = CCK_ImplicitConversion);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const StandardConversionSequence& SCS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK);

ExprResult PerformQualificationConversion(
    Expr *E, QualType Ty, ExprValueKind VK = VK_PRValue,
    CheckedConversionKind CCK = CCK_ImplicitConversion);

/// the following "Check" methods will return a valid/converted QualType
/// or a null QualType (indicating an error diagnostic was issued).

/// type checking binary operators (subroutines of CreateBuiltinBinOp).
QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
                         ExprResult &RHS);
QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
                               ExprResult &RHS);
QualType CheckPointerToMemberOperands( // C++ 5.5
  ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
  SourceLocation OpLoc, bool isIndirect);
QualType CheckMultiplyDivideOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, bool IsCompAssign,
  bool IsDivide);
QualType CheckRemainderOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  bool IsCompAssign = false);
QualType CheckAdditionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, QualType* CompLHSTy = nullptr);
QualType CheckSubtractionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  QualType* CompLHSTy = nullptr);
QualType CheckShiftOperands( // C99 6.5.7
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, bool IsCompAssign = false);
void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
QualType CheckCompareOperands( // C99 6.5.8/9
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckBitwiseOperands( // C99 6.5.[10...12]
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckLogicalOperands( // C99 6.5.[13,14]
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc);
// CheckAssignmentOperands is used for both simple and compound assignment.
// For simple assignment, pass both expressions and a null converted type.
// For compound assignment, pass both expressions and the converted type.
QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
  Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType);

ExprResult checkPseudoObjectIncDec(Scope *S, SourceLocation OpLoc,
                                   UnaryOperatorKind Opcode, Expr *Op);
ExprResult checkPseudoObjectAssignment(Scope *S, SourceLocation OpLoc,
                                       BinaryOperatorKind Opcode,
                                       Expr *LHS, Expr *RHS);
ExprResult checkPseudoObjectRValue(Expr *E);
Expr *recreateSyntacticForm(PseudoObjectExpr *E);

QualType CheckConditionalOperands( // C99 6.5.15
  ExprResult &Cond, ExprResult &LHS, ExprResult &RHS,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation QuestionLoc);
QualType CXXCheckConditionalOperands( // C++ 5.16
  ExprResult &cond, ExprResult &lhs, ExprResult &rhs,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation questionLoc);
QualType CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
                                     ExprResult &RHS,
                                     SourceLocation QuestionLoc);
QualType FindCompositePointerType(SourceLocation Loc, Expr *&E1, Expr *&E2,
                                  bool ConvertArgs = true);
QualType FindCompositePointerType(SourceLocation Loc,
                                  ExprResult &E1, ExprResult &E2,
                                  bool ConvertArgs = true) {
  Expr *E1Tmp = E1.get(), *E2Tmp = E2.get();
  QualType Composite =
      FindCompositePointerType(Loc, E1Tmp, E2Tmp, ConvertArgs);
  E1 = E1Tmp;
  E2 = E2Tmp;
  return Composite;
}

QualType FindCompositeObjCPointerType(ExprResult &LHS, ExprResult &RHS,
                                      SourceLocation QuestionLoc);

bool DiagnoseConditionalForNull(Expr *LHSExpr, Expr *RHSExpr,
                                SourceLocation QuestionLoc);

void DiagnoseAlwaysNonNullPointer(Expr *E,
                                  Expr::NullPointerConstantKind NullType,
                                  bool IsEqual, SourceRange Range);

/// type checking for vector binary operators.
QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
                             SourceLocation Loc, bool IsCompAssign,
                             bool AllowBothBool, bool AllowBoolConversion);
QualType GetSignedVectorType(QualType V);
QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc,
                                    BinaryOperatorKind Opc);
QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc);

/// Type checking for matrix binary operators.
QualType CheckMatrixElementwiseOperands(ExprResult &LHS, ExprResult &RHS,
                                        SourceLocation Loc,
                                        bool IsCompAssign);
QualType CheckMatrixMultiplyOperands(ExprResult &LHS, ExprResult &RHS,
                                     SourceLocation Loc, bool IsCompAssign);

bool isValidSveBitcast(QualType srcType, QualType destType);

bool areMatrixTypesOfTheSameDimension(QualType srcTy, QualType destTy);

bool areVectorTypesSameSize(QualType srcType, QualType destType);
bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
bool isLaxVectorConversion(QualType srcType, QualType destType);

/// type checking declaration initializers (C99 6.7.8)
bool CheckForConstantInitializer(Expr *e, QualType t);

// type checking C++ declaration initializers (C++ [dcl.init]).

/// ReferenceCompareResult - Expresses the result of comparing two
/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
enum ReferenceCompareResult {
  /// Ref_Incompatible - The two types are incompatible, so direct
  /// reference binding is not possible.
  Ref_Incompatible = 0,
  /// Ref_Related - The two types are reference-related, which means
  /// that their unqualified forms (T1 and T2) are either the same
  /// or T1 is a base class of T2.
  Ref_Related,
  /// Ref_Compatible - The two types are reference-compatible.
  Ref_Compatible
};

// Fake up a scoped enumeration that still contextually converts to bool.
struct ReferenceConversionsScope {
  /// The conversions that would be performed on an lvalue of type T2 when
  /// binding a reference of type T1 to it, as determined when evaluating
  /// whether T1 is reference-compatible with T2.
  enum ReferenceConversions {
    Qualification = 0x1,
    NestedQualification = 0x2,
    Function = 0x4,
    DerivedToBase = 0x8,
    ObjC = 0x10,
    ObjCLifetime = 0x20,

    LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/ObjCLifetime)LLVM_BITMASK_LARGEST_ENUMERATOR = ObjCLifetime
  };
};
using ReferenceConversions = ReferenceConversionsScope::ReferenceConversions;

ReferenceCompareResult
CompareReferenceRelationship(SourceLocation Loc, QualType T1, QualType T2,
                             ReferenceConversions *Conv = nullptr);

ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
                               Expr *CastExpr, CastKind &CastKind,
                               ExprValueKind &VK, CXXCastPath &Path);

/// Force an expression with unknown-type to an expression of the
/// given type.
ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);

/// Type-check an expression that's being passed to an
/// __unknown_anytype parameter.
ExprResult checkUnknownAnyArg(SourceLocation callLoc,
                              Expr *result, QualType &paramType);

// CheckMatrixCast - Check type constraints for matrix casts.
// We allow casting between matrixes of the same dimensions i.e. when they
// have the same number of rows and column. Returns true if the cast is
// invalid.
bool CheckMatrixCast(SourceRange R, QualType DestTy, QualType SrcTy,
                     CastKind &Kind);

// CheckVectorCast - check type constraints for vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size.
// returns true if the cast is invalid
bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
                     CastKind &Kind);

/// Prepare `SplattedExpr` for a vector splat operation, adding
/// implicit casts if necessary.
ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);

// CheckExtVectorCast - check type constraints for extended vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size,
// or vectors and the element type of that vector.
// returns the cast expr
ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
                              CastKind &Kind);

ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
                                      SourceLocation LParenLoc,
                                      Expr *CastExpr,
                                      SourceLocation RParenLoc);

enum ARCConversionResult { ACR_okay, ACR_unbridged, ACR_error };

/// Checks for invalid conversions and casts between
/// retainable pointers and other pointer kinds for ARC and Weak.
ARCConversionResult CheckObjCConversion(SourceRange castRange,
                                        QualType castType, Expr *&op,
                                        CheckedConversionKind CCK,
                                        bool Diagnose = true,
                                        bool DiagnoseCFAudited = false,
                                        BinaryOperatorKind Opc = BO_PtrMemD
                                        );

Expr *stripARCUnbridgedCast(Expr *e);
void diagnoseARCUnbridgedCast(Expr *e);

bool CheckObjCARCUnavailableWeakConversion(QualType castType,
                                           QualType ExprType);

/// checkRetainCycles - Check whether an Objective-C message send
/// might create an obvious retain cycle.
void checkRetainCycles(ObjCMessageExpr *msg);
void checkRetainCycles(Expr *receiver, Expr *argument);
void checkRetainCycles(VarDecl *Var, Expr *Init);

/// checkUnsafeAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained type.
bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);

/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained expression.
void checkUnsafeExprAssigns(SourceLocation Loc, Expr *LHS, Expr *RHS);

/// CheckMessageArgumentTypes - Check types in an Obj-C message send.
/// \param Method - May be null.
/// \param [out] ReturnType - The return type of the send.
/// \return true iff there were any incompatible types.
bool CheckMessageArgumentTypes(const Expr *Receiver, QualType ReceiverType,
                               MultiExprArg Args, Selector Sel,
                               ArrayRef<SourceLocation> SelectorLocs,
                               ObjCMethodDecl *Method, bool isClassMessage,
                               bool isSuperMessage, SourceLocation lbrac,
                               SourceLocation rbrac, SourceRange RecRange,
                               QualType &ReturnType, ExprValueKind &VK);

/// Determine the result of a message send expression based on
/// the type of the receiver, the method expected to receive the message,
/// and the form of the message send.
QualType getMessageSendResultType(const Expr *Receiver, QualType ReceiverType,
                                  ObjCMethodDecl *Method, bool isClassMessage,
                                  bool isSuperMessage);

/// If the given expression involves a message send to a method
/// with a related result type, emit a note describing what happened.
void EmitRelatedResultTypeNote(const Expr *E);

/// Given that we had incompatible pointer types in a return
/// statement, check whether we're in a method with a related result
/// type, and if so, emit a note describing what happened.
void EmitRelatedResultTypeNoteForReturn(QualType destType);

class ConditionResult {
  Decl *ConditionVar;
  FullExprArg Condition;
  bool Invalid;
  bool HasKnownValue;
  bool KnownValue;

  friend class Sema;
  ConditionResult(Sema &S, Decl *ConditionVar, FullExprArg Condition,
                  bool IsConstexpr)
      : ConditionVar(ConditionVar), Condition(Condition), Invalid(false),
        HasKnownValue(IsConstexpr && Condition.get() &&
                      !Condition.get()->isValueDependent()),
        KnownValue(HasKnownValue &&
                   !!Condition.get()->EvaluateKnownConstInt(S.Context)) {}
  explicit ConditionResult(bool Invalid)
      : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid),
        HasKnownValue(false), KnownValue(false) {}

public:
  ConditionResult() : ConditionResult(false) {}
  bool isInvalid() const { return Invalid; }
  std::pair<VarDecl *, Expr *> get() const {
    return std::make_pair(cast_or_null<VarDecl>(ConditionVar),
                          Condition.get());
  }
  llvm::Optional<bool> getKnownValue() const {
    if (!HasKnownValue)
      return None;
    return KnownValue;
  }
};
static ConditionResult ConditionError() { return ConditionResult(true); }

enum class ConditionKind {
  Boolean,     ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
  ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
  Switch       ///< An integral condition for a 'switch' statement.
};

ConditionResult ActOnCondition(Scope *S, SourceLocation Loc,
                               Expr *SubExpr, ConditionKind CK);

ConditionResult ActOnConditionVariable(Decl *ConditionVar,
                                       SourceLocation StmtLoc,
                                       ConditionKind CK);

DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);

ExprResult CheckConditionVariable(VarDecl *ConditionVar,
                                  SourceLocation StmtLoc,
                                  ConditionKind CK);
ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);

/// CheckBooleanCondition - Diagnose problems involving the use of
/// the given expression as a boolean condition (e.g. in an if
/// statement).  Also performs the standard function and array
/// decays, possibly changing the input variable.
///
/// \param Loc - A location associated with the condition, e.g. the
/// 'if' keyword.
/// \return true iff there were any errors
ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
                                 bool IsConstexpr = false);

/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
/// found in an explicit(bool) specifier.
ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);

/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
/// Returns true if the explicit specifier is now resolved.
bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);

/// DiagnoseAssignmentAsCondition - Given that an expression is
/// being used as a boolean condition, warn if it's an assignment.
void DiagnoseAssignmentAsCondition(Expr *E);

/// Redundant parentheses over an equality comparison can indicate
/// that the user intended an assignment used as condition.
void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);

/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
ExprResult CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr = false);

/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
/// the specified width and sign.  If an overflow occurs, detect it and emit
/// the specified diagnostic.
void ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &OldVal,
                                        unsigned NewWidth, bool NewSign,
                                        SourceLocation Loc, unsigned DiagID);

/// Checks that the Objective-C declaration is declared in the global scope.
/// Emits an error and marks the declaration as invalid if it's not declared
/// in the global scope.
bool CheckObjCDeclScope(Decl *D);

/// Abstract base class used for diagnosing integer constant
/// expression violations.
class VerifyICEDiagnoser {
public:
  bool Suppress;

  VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) { }

  virtual SemaDiagnosticBuilder
  diagnoseNotICEType(Sema &S, SourceLocation Loc, QualType T);
  virtual SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
                                               SourceLocation Loc) = 0;
  virtual SemaDiagnosticBuilder diagnoseFold(Sema &S, SourceLocation Loc);
  virtual ~VerifyICEDiagnoser() {}
};

enum AllowFoldKind {
  NoFold,
  AllowFold,
};

/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
/// and reports the appropriate diagnostics. Returns false on success.
/// Can optionally return the value of the expression.
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           VerifyICEDiagnoser &Diagnoser,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           unsigned DiagID,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E,
                                           llvm::APSInt *Result = nullptr,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E,
                                           AllowFoldKind CanFold = NoFold) {
  return VerifyIntegerConstantExpression(E, nullptr, CanFold);
}

/// VerifyBitField - verifies that a bit field expression is an ICE and has
/// the correct width, and that the field type is valid.
/// Returns false on success.
/// Can optionally return whether the bit-field is of width 0
ExprResult VerifyBitField(SourceLocation FieldLoc, IdentifierInfo *FieldName,
                          QualType FieldTy, bool IsMsStruct,
                          Expr *BitWidth, bool *ZeroWidth = nullptr);

12039private:
unsigned ForceCUDAHostDeviceDepth = 0;

12042public:
/// Increments our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  So long as this count is greater
/// than zero, all functions encountered will be __host__ __device__.
void PushForceCUDAHostDevice();

/// Decrements our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  Returns false if the count is 0
/// before incrementing, so you can emit an error.
bool PopForceCUDAHostDevice();

/// Diagnostics that are emitted only if we discover that the given function
/// must be codegen'ed.  Because handling these correctly adds overhead to
/// compilation, this is currently only enabled for CUDA compilations.
llvm::DenseMap<CanonicalDeclPtr<FunctionDecl>,
               std::vector<PartialDiagnosticAt>>
    DeviceDeferredDiags;

/// A pair of a canonical FunctionDecl and a SourceLocation.  When used as the
/// key in a hashtable, both the FD and location are hashed.
struct FunctionDeclAndLoc {
  CanonicalDeclPtr<FunctionDecl> FD;
  SourceLocation Loc;
};

/// FunctionDecls and SourceLocations for which CheckCUDACall has emitted a
/// (maybe deferred) "bad call" diagnostic.  We use this to avoid emitting the
/// same deferred diag twice.
llvm::DenseSet<FunctionDeclAndLoc> LocsWithCUDACallDiags;

/// An inverse call graph, mapping known-emitted functions to one of their
/// known-emitted callers (plus the location of the call).
///
/// Functions that we can tell a priori must be emitted aren't added to this
/// map.
llvm::DenseMap</* Callee = */ CanonicalDeclPtr<FunctionDecl>,
               /* Caller = */ FunctionDeclAndLoc>
    DeviceKnownEmittedFns;

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurContext is a __host__ function, does not emit any diagnostics
///   unless \p EmitOnBothSides is true.
/// - If CurContext is a __device__ or __global__ function, emits the
///   diagnostics immediately.
/// - If CurContext is a __host__ __device__ function and we are compiling for
///   the device, creates a diagnostic which is emitted if and when we realize
///   that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in CUDA device code.
///  if (CUDADiagIfDeviceCode(Loc, diag::err_cuda_vla) << CurrentCUDATarget())
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder CUDADiagIfDeviceCode(SourceLocation Loc,
                                           unsigned DiagID);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as host code".
///
/// Same as CUDADiagIfDeviceCode, with "host" and "device" switched.
SemaDiagnosticBuilder CUDADiagIfHostCode(SourceLocation Loc, unsigned DiagID);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the device, emits the diagnostics immediately.
/// - If CurContext is a non-`declare target` function and we are compiling
///   for the device, creates a diagnostic which is emitted if and when we
///   realize that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPDeviceCode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder
diagIfOpenMPDeviceCode(SourceLocation Loc, unsigned DiagID, FunctionDecl *FD);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as host code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the host, emits the diagnostics immediately.
/// - If CurContext is a non-host function, just ignore it.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPHostode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder diagIfOpenMPHostCode(SourceLocation Loc,
                                           unsigned DiagID, FunctionDecl *FD);

SemaDiagnosticBuilder targetDiag(SourceLocation Loc, unsigned DiagID,
                                 FunctionDecl *FD = nullptr);
SemaDiagnosticBuilder targetDiag(SourceLocation Loc,
                                 const PartialDiagnostic &PD,
                                 FunctionDecl *FD = nullptr) {
  return targetDiag(Loc, PD.getDiagID(), FD) << PD;
}

/// Check if the expression is allowed to be used in expressions for the
/// offloading devices.
void checkDeviceDecl(ValueDecl *D, SourceLocation Loc);

enum CUDAFunctionTarget {
  CFT_Device,
  CFT_Global,
  CFT_Host,
  CFT_HostDevice,
  CFT_InvalidTarget
};

/// Determines whether the given function is a CUDA device/host/kernel/etc.
/// function.
///
/// Use this rather than examining the function's attributes yourself -- you
/// will get it wrong.  Returns CFT_Host if D is null.
CUDAFunctionTarget IdentifyCUDATarget(const FunctionDecl *D,
                                      bool IgnoreImplicitHDAttr = false);
CUDAFunctionTarget IdentifyCUDATarget(const ParsedAttributesView &Attrs);

enum CUDAVariableTarget {
  CVT_Device,  /// Emitted on device side with a shadow variable on host side
  CVT_Host,    /// Emitted on host side only
  CVT_Both,    /// Emitted on both sides with different addresses
  CVT_Unified, /// Emitted as a unified address, e.g. managed variables
};
/// Determines whether the given variable is emitted on host or device side.
CUDAVariableTarget IdentifyCUDATarget(const VarDecl *D);

/// Gets the CUDA target for the current context.
CUDAFunctionTarget CurrentCUDATarget() {
  return IdentifyCUDATarget(dyn_cast<FunctionDecl>(CurContext));
}

static bool isCUDAImplicitHostDeviceFunction(const FunctionDecl *D);

// CUDA function call preference. Must be ordered numerically from
// worst to best.
enum CUDAFunctionPreference {
  CFP_Never,      // Invalid caller/callee combination.
  CFP_WrongSide,  // Calls from host-device to host or device
                  // function that do not match current compilation
                  // mode.
  CFP_HostDevice, // Any calls to host/device functions.
  CFP_SameSide,   // Calls from host-device to host or device
                  // function matching current compilation mode.
  CFP_Native,     // host-to-host or device-to-device calls.
};

/// Identifies relative preference of a given Caller/Callee
/// combination, based on their host/device attributes.
/// \param Caller function which needs address of \p Callee.
///               nullptr in case of global context.
/// \param Callee target function
///
/// \returns preference value for particular Caller/Callee combination.
CUDAFunctionPreference IdentifyCUDAPreference(const FunctionDecl *Caller,
                                              const FunctionDecl *Callee);

/// Determines whether Caller may invoke Callee, based on their CUDA
/// host/device attributes.  Returns false if the call is not allowed.
///
/// Note: Will return true for CFP_WrongSide calls.  These may appear in
/// semantically correct CUDA programs, but only if they're never codegen'ed.
bool IsAllowedCUDACall(const FunctionDecl *Caller,
                       const FunctionDecl *Callee) {
  return IdentifyCUDAPreference(Caller, Callee) != CFP_Never;
}

/// May add implicit CUDAHostAttr and CUDADeviceAttr attributes to FD,
/// depending on FD and the current compilation settings.
void maybeAddCUDAHostDeviceAttrs(FunctionDecl *FD,
                                 const LookupResult &Previous);

/// May add implicit CUDAConstantAttr attribute to VD, depending on VD
/// and current compilation settings.
void MaybeAddCUDAConstantAttr(VarDecl *VD);

12228public:
/// Check whether we're allowed to call Callee from the current context.
///
/// - If the call is never allowed in a semantically-correct program
///   (CFP_Never), emits an error and returns false.
///
/// - If the call is allowed in semantically-correct programs, but only if
///   it's never codegen'ed (CFP_WrongSide), creates a deferred diagnostic to
///   be emitted if and when the caller is codegen'ed, and returns true.
///
///   Will only create deferred diagnostics for a given SourceLocation once,
///   so you can safely call this multiple times without generating duplicate
///   deferred errors.
///
/// - Otherwise, returns true without emitting any diagnostics.
bool CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee);

void CUDACheckLambdaCapture(CXXMethodDecl *D, const sema::Capture &Capture);

/// Set __device__ or __host__ __device__ attributes on the given lambda
/// operator() method.
///
/// CUDA lambdas by default is host device function unless it has explicit
/// host or device attribute.
void CUDASetLambdaAttrs(CXXMethodDecl *Method);

/// Finds a function in \p Matches with highest calling priority
/// from \p Caller context and erases all functions with lower
/// calling priority.
void EraseUnwantedCUDAMatches(
    const FunctionDecl *Caller,
    SmallVectorImpl<std::pair<DeclAccessPair, FunctionDecl *>> &Matches);

/// Given a implicit special member, infer its CUDA target from the
/// calls it needs to make to underlying base/field special members.
/// \param ClassDecl the class for which the member is being created.
/// \param CSM the kind of special member.
/// \param MemberDecl the special member itself.
/// \param ConstRHS true if this is a copy operation with a const object on
///        its RHS.
/// \param Diagnose true if this call should emit diagnostics.
/// \return true if there was an error inferring.
/// The result of this call is implicit CUDA target attribute(s) attached to
/// the member declaration.
bool inferCUDATargetForImplicitSpecialMember(CXXRecordDecl *ClassDecl,
                                             CXXSpecialMember CSM,
                                             CXXMethodDecl *MemberDecl,
                                             bool ConstRHS,
                                             bool Diagnose);

/// \return true if \p CD can be considered empty according to CUDA
/// (E.2.3.1 in CUDA 7.5 Programming guide).
bool isEmptyCudaConstructor(SourceLocation Loc, CXXConstructorDecl *CD);
bool isEmptyCudaDestructor(SourceLocation Loc, CXXDestructorDecl *CD);

// \brief Checks that initializers of \p Var satisfy CUDA restrictions. In
// case of error emits appropriate diagnostic and invalidates \p Var.
//
// \details CUDA allows only empty constructors as initializers for global
// variables (see E.2.3.1, CUDA 7.5). The same restriction also applies to all
// __shared__ variables whether they are local or not (they all are implicitly
// static in CUDA). One exception is that CUDA allows constant initializers
// for __constant__ and __device__ variables.
void checkAllowedCUDAInitializer(VarDecl *VD);

/// Check whether NewFD is a valid overload for CUDA. Emits
/// diagnostics and invalidates NewFD if not.
void checkCUDATargetOverload(FunctionDecl *NewFD,
                             const LookupResult &Previous);
/// Copies target attributes from the template TD to the function FD.
void inheritCUDATargetAttrs(FunctionDecl *FD, const FunctionTemplateDecl &TD);

/// Returns the name of the launch configuration function.  This is the name
/// of the function that will be called to configure kernel call, with the
/// parameters specified via <<<>>>.
std::string getCudaConfigureFuncName() const;

/// \name Code completion
//@{
/// Describes the context in which code completion occurs.
enum ParserCompletionContext {
  /// Code completion occurs at top-level or namespace context.
  PCC_Namespace,
  /// Code completion occurs within a class, struct, or union.
  PCC_Class,
  /// Code completion occurs within an Objective-C interface, protocol,
  /// or category.
  PCC_ObjCInterface,
  /// Code completion occurs within an Objective-C implementation or
  /// category implementation
  PCC_ObjCImplementation,
  /// Code completion occurs within the list of instance variables
  /// in an Objective-C interface, protocol, category, or implementation.
  PCC_ObjCInstanceVariableList,
  /// Code completion occurs following one or more template
  /// headers.
  PCC_Template,
  /// Code completion occurs following one or more template
  /// headers within a class.
  PCC_MemberTemplate,
  /// Code completion occurs within an expression.
  PCC_Expression,
  /// Code completion occurs within a statement, which may
  /// also be an expression or a declaration.
  PCC_Statement,
  /// Code completion occurs at the beginning of the
  /// initialization statement (or expression) in a for loop.
  PCC_ForInit,
  /// Code completion occurs within the condition of an if,
  /// while, switch, or for statement.
  PCC_Condition,
  /// Code completion occurs within the body of a function on a
  /// recovery path, where we do not have a specific handle on our position
  /// in the grammar.
  PCC_RecoveryInFunction,
  /// Code completion occurs where only a type is permitted.
  PCC_Type,
  /// Code completion occurs in a parenthesized expression, which
  /// might also be a type cast.
  PCC_ParenthesizedExpression,
  /// Code completion occurs within a sequence of declaration
  /// specifiers within a function, method, or block.
  PCC_LocalDeclarationSpecifiers
};

void CodeCompleteModuleImport(SourceLocation ImportLoc, ModuleIdPath Path);
void CodeCompleteOrdinaryName(Scope *S,
                              ParserCompletionContext CompletionContext);
void CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
                          bool AllowNonIdentifiers,
                          bool AllowNestedNameSpecifiers);

struct CodeCompleteExpressionData;
void CodeCompleteExpression(Scope *S,
                            const CodeCompleteExpressionData &Data);
void CodeCompleteExpression(Scope *S, QualType PreferredType,
                            bool IsParenthesized = false);
void CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base, Expr *OtherOpBase,
                                     SourceLocation OpLoc, bool IsArrow,
                                     bool IsBaseExprStatement,
                                     QualType PreferredType);
void CodeCompletePostfixExpression(Scope *S, ExprResult LHS,
                                   QualType PreferredType);
void CodeCompleteTag(Scope *S, unsigned TagSpec);
void CodeCompleteTypeQualifiers(DeclSpec &DS);
void CodeCompleteFunctionQualifiers(DeclSpec &DS, Declarator &D,
                                    const VirtSpecifiers *VS = nullptr);
void CodeCompleteBracketDeclarator(Scope *S);
void CodeCompleteCase(Scope *S);
/// Determines the preferred type of the current function argument, by
/// examining the signatures of all possible overloads.
/// Returns null if unknown or ambiguous, or if code completion is off.
///
/// If the code completion point has been reached, also reports the function
/// signatures that were considered.
///
/// FIXME: rename to GuessCallArgumentType to reduce confusion.
QualType ProduceCallSignatureHelp(Scope *S, Expr *Fn, ArrayRef<Expr *> Args,
                                  SourceLocation OpenParLoc);
QualType ProduceConstructorSignatureHelp(Scope *S, QualType Type,
                                         SourceLocation Loc,
                                         ArrayRef<Expr *> Args,
                                         SourceLocation OpenParLoc);
QualType ProduceCtorInitMemberSignatureHelp(Scope *S, Decl *ConstructorDecl,
                                            CXXScopeSpec SS,
                                            ParsedType TemplateTypeTy,
                                            ArrayRef<Expr *> ArgExprs,
                                            IdentifierInfo *II,
                                            SourceLocation OpenParLoc);
void CodeCompleteInitializer(Scope *S, Decl *D);
/// Trigger code completion for a record of \p BaseType. \p InitExprs are
/// expressions in the initializer list seen so far and \p D is the current
/// Designation being parsed.
void CodeCompleteDesignator(const QualType BaseType,
                            llvm::ArrayRef<Expr *> InitExprs,
                            const Designation &D);
void CodeCompleteAfterIf(Scope *S, bool IsBracedThen);

void CodeCompleteQualifiedId(Scope *S, CXXScopeSpec &SS, bool EnteringContext,
                             bool IsUsingDeclaration, QualType BaseType,
                             QualType PreferredType);
void CodeCompleteUsing(Scope *S);
void CodeCompleteUsingDirective(Scope *S);
void CodeCompleteNamespaceDecl(Scope *S);
void CodeCompleteNamespaceAliasDecl(Scope *S);
void CodeCompleteOperatorName(Scope *S);
void CodeCompleteConstructorInitializer(
                              Decl *Constructor,
                              ArrayRef<CXXCtorInitializer *> Initializers);

void CodeCompleteLambdaIntroducer(Scope *S, LambdaIntroducer &Intro,
                                  bool AfterAmpersand);
void CodeCompleteAfterFunctionEquals(Declarator &D);

void CodeCompleteObjCAtDirective(Scope *S);
void CodeCompleteObjCAtVisibility(Scope *S);
void CodeCompleteObjCAtStatement(Scope *S);
void CodeCompleteObjCAtExpression(Scope *S);
void CodeCompleteObjCPropertyFlags(Scope *S, ObjCDeclSpec &ODS);
void CodeCompleteObjCPropertyGetter(Scope *S);
void CodeCompleteObjCPropertySetter(Scope *S);
void CodeCompleteObjCPassingType(Scope *S, ObjCDeclSpec &DS,
                                 bool IsParameter);
void CodeCompleteObjCMessageReceiver(Scope *S);
void CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression);
void CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression,
                                  bool IsSuper = false);
void CodeCompleteObjCInstanceMessage(Scope *S, Expr *Receiver,
                                     ArrayRef<IdentifierInfo *> SelIdents,
                                     bool AtArgumentExpression,
                                     ObjCInterfaceDecl *Super = nullptr);
void CodeCompleteObjCForCollection(Scope *S,
                                   DeclGroupPtrTy IterationVar);
void CodeCompleteObjCSelector(Scope *S,
                              ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCProtocolReferences(
                                       ArrayRef<IdentifierLocPair> Protocols);
void CodeCompleteObjCProtocolDecl(Scope *S);
void CodeCompleteObjCInterfaceDecl(Scope *S);
void CodeCompleteObjCSuperclass(Scope *S,
                                IdentifierInfo *ClassName,
                                SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationDecl(Scope *S);
void CodeCompleteObjCInterfaceCategory(Scope *S,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationCategory(Scope *S,
                                            IdentifierInfo *ClassName,
                                            SourceLocation ClassNameLoc);
void CodeCompleteObjCPropertyDefinition(Scope *S);
void CodeCompleteObjCPropertySynthesizeIvar(Scope *S,
                                            IdentifierInfo *PropertyName);
void CodeCompleteObjCMethodDecl(Scope *S, Optional<bool> IsInstanceMethod,
                                ParsedType ReturnType);
void CodeCompleteObjCMethodDeclSelector(Scope *S,
                                        bool IsInstanceMethod,
                                        bool AtParameterName,
                                        ParsedType ReturnType,
                                        ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCClassPropertyRefExpr(Scope *S, IdentifierInfo &ClassName,
                                          SourceLocation ClassNameLoc,
                                          bool IsBaseExprStatement);
void CodeCompletePreprocessorDirective(bool InConditional);
void CodeCompleteInPreprocessorConditionalExclusion(Scope *S);
void CodeCompletePreprocessorMacroName(bool IsDefinition);
void CodeCompletePreprocessorExpression();
void CodeCompletePreprocessorMacroArgument(Scope *S,
                                           IdentifierInfo *Macro,
                                           MacroInfo *MacroInfo,
                                           unsigned Argument);
void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled);
void CodeCompleteNaturalLanguage();
void CodeCompleteAvailabilityPlatformName();
void GatherGlobalCodeCompletions(CodeCompletionAllocator &Allocator,
                                 CodeCompletionTUInfo &CCTUInfo,
                SmallVectorImpl<CodeCompletionResult> &Results);
//@}

//===--------------------------------------------------------------------===//
// Extra semantic analysis beyond the C type system

12493public:
SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
                                              unsigned ByteNo) const;

12497private:
void CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                      const ArraySubscriptExpr *ASE=nullptr,
                      bool AllowOnePastEnd=true, bool IndexNegated=false);
void CheckArrayAccess(const Expr *E);
// Used to grab the relevant information from a FormatAttr and a
// FunctionDeclaration.
struct FormatStringInfo {
  unsigned FormatIdx;
  unsigned FirstDataArg;
  bool HasVAListArg;
};

static bool getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
                                FormatStringInfo *FSI);
bool CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
                       const FunctionProtoType *Proto);
bool CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation loc,
                         ArrayRef<const Expr *> Args);
bool CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
                      const FunctionProtoType *Proto);
bool CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto);
void CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
                          ArrayRef<const Expr *> Args,
                          const FunctionProtoType *Proto, SourceLocation Loc);

void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
                       StringRef ParamName, QualType ArgTy, QualType ParamTy);

void checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
               const Expr *ThisArg, ArrayRef<const Expr *> Args,
               bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
               VariadicCallType CallType);

bool CheckObjCString(Expr *Arg);
ExprResult CheckOSLogFormatStringArg(Expr *Arg);

ExprResult CheckBuiltinFunctionCall(FunctionDecl *FDecl,
                                    unsigned BuiltinID, CallExpr *TheCall);

bool CheckTSBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                CallExpr *TheCall);

void checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD, CallExpr *TheCall);

bool CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
                                  unsigned MaxWidth);
bool CheckNeonBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                  CallExpr *TheCall);
bool CheckMVEBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckSVEBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckCDEBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckARMCoprocessorImmediate(const TargetInfo &TI, const Expr *CoprocArg,
                                  bool WantCDE);
bool CheckARMBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);

bool CheckAArch64BuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                     CallExpr *TheCall);
bool CheckBPFBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinArgument(unsigned BuiltinID, CallExpr *TheCall);
bool CheckMipsBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                  CallExpr *TheCall);
bool CheckMipsBuiltinCpu(const TargetInfo &TI, unsigned BuiltinID,
                         CallExpr *TheCall);
bool CheckMipsBuiltinArgument(unsigned BuiltinID, CallExpr *TheCall);
bool CheckSystemZBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinRoundingOrSAE(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinGatherScatterScale(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinTileArguments(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinTileArgumentsRange(CallExpr *TheCall,
                                       ArrayRef<int> ArgNums);
bool CheckX86BuiltinTileDuplicate(CallExpr *TheCall, ArrayRef<int> ArgNums);
bool CheckX86BuiltinTileRangeAndDuplicate(CallExpr *TheCall,
                                          ArrayRef<int> ArgNums);
bool CheckX86BuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckPPCBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckAMDGCNBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckRISCVLMUL(CallExpr *TheCall, unsigned ArgNum);
bool CheckRISCVBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                   CallExpr *TheCall);

bool SemaBuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
bool SemaBuiltinVAStartARMMicrosoft(CallExpr *Call);
bool SemaBuiltinUnorderedCompare(CallExpr *TheCall);
bool SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs);
bool SemaBuiltinComplex(CallExpr *TheCall);
bool SemaBuiltinVSX(CallExpr *TheCall);
bool SemaBuiltinOSLogFormat(CallExpr *TheCall);
bool SemaValueIsRunOfOnes(CallExpr *TheCall, unsigned ArgNum);

12592public:
// Used by C++ template instantiation.
ExprResult SemaBuiltinShuffleVector(CallExpr *TheCall);
ExprResult SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
                                 SourceLocation BuiltinLoc,
                                 SourceLocation RParenLoc);

12599private:
bool SemaBuiltinPrefetch(CallExpr *TheCall);
bool SemaBuiltinAllocaWithAlign(CallExpr *TheCall);
bool SemaBuiltinArithmeticFence(CallExpr *TheCall);
bool SemaBuiltinAssume(CallExpr *TheCall);
bool SemaBuiltinAssumeAligned(CallExpr *TheCall);
bool SemaBuiltinLongjmp(CallExpr *TheCall);
bool SemaBuiltinSetjmp(CallExpr *TheCall);
ExprResult SemaBuiltinAtomicOverloaded(ExprResult TheCallResult);
ExprResult SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult);
ExprResult SemaAtomicOpsOverloaded(ExprResult TheCallResult,
                                   AtomicExpr::AtomicOp Op);
ExprResult SemaBuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
                                                  bool IsDelete);
bool SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
                            llvm::APSInt &Result);
bool SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, int Low,
                                 int High, bool RangeIsError = true);
bool SemaBuiltinConstantArgMultiple(CallExpr *TheCall, int ArgNum,
                                    unsigned Multiple);
bool SemaBuiltinConstantArgPower2(CallExpr *TheCall, int ArgNum);
bool SemaBuiltinConstantArgShiftedByte(CallExpr *TheCall, int ArgNum,
                                       unsigned ArgBits);
bool SemaBuiltinConstantArgShiftedByteOrXXFF(CallExpr *TheCall, int ArgNum,
                                             unsigned ArgBits);
bool SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
                              int ArgNum, unsigned ExpectedFieldNum,
                              bool AllowName);
bool SemaBuiltinARMMemoryTaggingCall(unsigned BuiltinID, CallExpr *TheCall);
bool SemaBuiltinPPCMMACall(CallExpr *TheCall, const char *TypeDesc);

bool CheckPPCMMAType(QualType Type, SourceLocation TypeLoc);

// Matrix builtin handling.
ExprResult SemaBuiltinMatrixTranspose(CallExpr *TheCall,
                                      ExprResult CallResult);
ExprResult SemaBuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
                                            ExprResult CallResult);
ExprResult SemaBuiltinMatrixColumnMajorStore(CallExpr *TheCall,
                                             ExprResult CallResult);

12640public:
enum FormatStringType {
  FST_Scanf,
  FST_Printf,
  FST_NSString,
  FST_Strftime,
  FST_Strfmon,
  FST_Kprintf,
  FST_FreeBSDKPrintf,
  FST_OSTrace,
  FST_OSLog,
  FST_Syslog,
  FST_Unknown
};
static FormatStringType GetFormatStringType(const FormatAttr *Format);

bool FormatStringHasSArg(const StringLiteral *FExpr);

static bool GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx);

12660private:
bool CheckFormatArguments(const FormatAttr *Format,
                          ArrayRef<const Expr *> Args,
                          bool IsCXXMember,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange Range,
                          llvm::SmallBitVector &CheckedVarArgs);
bool CheckFormatArguments(ArrayRef<const Expr *> Args,
                          bool HasVAListArg, unsigned format_idx,
                          unsigned firstDataArg, FormatStringType Type,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange range,
                          llvm::SmallBitVector &CheckedVarArgs);

void CheckAbsoluteValueFunction(const CallExpr *Call,
                                const FunctionDecl *FDecl);

void CheckMaxUnsignedZero(const CallExpr *Call, const FunctionDecl *FDecl);

void CheckMemaccessArguments(const CallExpr *Call,
                             unsigned BId,
                             IdentifierInfo *FnName);

void CheckStrlcpycatArguments(const CallExpr *Call,
                              IdentifierInfo *FnName);

void CheckStrncatArguments(const CallExpr *Call,
                           IdentifierInfo *FnName);

void CheckFreeArguments(const CallExpr *E);

void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
                        SourceLocation ReturnLoc,
                        bool isObjCMethod = false,
                        const AttrVec *Attrs = nullptr,
                        const FunctionDecl *FD = nullptr);

12697public:
void CheckFloatComparison(SourceLocation Loc, Expr *LHS, Expr *RHS);

12700private:
void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation());
void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
void CheckForIntOverflow(Expr *E);
void CheckUnsequencedOperations(const Expr *E);

/// Perform semantic checks on a completed expression. This will either
/// be a full-expression or a default argument expression.
void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation(),
                        bool IsConstexpr = false);

void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
                                 Expr *Init);

/// Check if there is a field shadowing.
void CheckShadowInheritedFields(const SourceLocation &Loc,
                                DeclarationName FieldName,
                                const CXXRecordDecl *RD,
                                bool DeclIsField = true);

/// Check if the given expression contains 'break' or 'continue'
/// statement that produces control flow different from GCC.
void CheckBreakContinueBinding(Expr *E);

/// Check whether receiver is mutable ObjC container which
/// attempts to add itself into the container
void CheckObjCCircularContainer(ObjCMessageExpr *Message);

void CheckTCBEnforcement(const CallExpr *TheCall, const FunctionDecl *Callee);

void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
                               bool DeleteWasArrayForm);
12733public:
/// Register a magic integral constant to be used as a type tag.
void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
                                uint64_t MagicValue, QualType Type,
                                bool LayoutCompatible, bool MustBeNull);

struct TypeTagData {
  TypeTagData() {}

  TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull) :
      Type(Type), LayoutCompatible(LayoutCompatible),
      MustBeNull(MustBeNull)
  {}

  QualType Type;

  /// If true, \c Type should be compared with other expression's types for
  /// layout-compatibility.
  unsigned LayoutCompatible : 1;
  unsigned MustBeNull : 1;
};

/// A pair of ArgumentKind identifier and magic value.  This uniquely
/// identifies the magic value.
typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;

12759private:
/// A map from magic value to type information.
std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
    TypeTagForDatatypeMagicValues;

/// Peform checks on a call of a function with argument_with_type_tag
/// or pointer_with_type_tag attributes.
void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
                              const ArrayRef<const Expr *> ExprArgs,
                              SourceLocation CallSiteLoc);

/// Check if we are taking the address of a packed field
/// as this may be a problem if the pointer value is dereferenced.
void CheckAddressOfPackedMember(Expr *rhs);

/// The parser's current scope.
///
/// The parser maintains this state here.
Scope *CurScope;

mutable IdentifierInfo *Ident_super;
mutable IdentifierInfo *Ident___float128;

/// Nullability type specifiers.
IdentifierInfo *Ident__Nonnull = nullptr;
IdentifierInfo *Ident__Nullable = nullptr;
IdentifierInfo *Ident__Nullable_result = nullptr;
IdentifierInfo *Ident__Null_unspecified = nullptr;

IdentifierInfo *Ident_NSError = nullptr;

/// The handler for the FileChanged preprocessor events.
///
/// Used for diagnostics that implement custom semantic analysis for #include
/// directives, like -Wpragma-pack.
sema::SemaPPCallbacks *SemaPPCallbackHandler;

12796protected:
friend class Parser;
friend class InitializationSequence;
friend class ASTReader;
friend class ASTDeclReader;
friend class ASTWriter;

12803public:
/// Retrieve the keyword associated
IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);

/// The struct behind the CFErrorRef pointer.
RecordDecl *CFError = nullptr;
bool isCFError(RecordDecl *D);

/// Retrieve the identifier "NSError".
IdentifierInfo *getNSErrorIdent();

/// Retrieve the parser's current scope.
///
/// This routine must only be used when it is certain that semantic analysis
/// and the parser are in precisely the same context, which is not the case
/// when, e.g., we are performing any kind of template instantiation.
/// Therefore, the only safe places to use this scope are in the parser
/// itself and in routines directly invoked from the parser and *never* from
/// template substitution or instantiation.
Scope *getCurScope() const { return CurScope; }

void incrementMSManglingNumber() const {
  return CurScope->incrementMSManglingNumber();
}

IdentifierInfo *getSuperIdentifier() const;
IdentifierInfo *getFloat128Identifier() const;

Decl *getObjCDeclContext() const;

DeclContext *getCurLexicalContext() const {
  return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
}

const DeclContext *getCurObjCLexicalContext() const {
  const DeclContext *DC = getCurLexicalContext();
  // A category implicitly has the attribute of the interface.
  if (const ObjCCategoryDecl *CatD = dyn_cast<ObjCCategoryDecl>(DC))
    DC = CatD->getClassInterface();
  return DC;
}

/// Determine the number of levels of enclosing template parameters. This is
/// only usable while parsing. Note that this does not include dependent
/// contexts in which no template parameters have yet been declared, such as
/// in a terse function template or generic lambda before the first 'auto' is
/// encountered.
unsigned getTemplateDepth(Scope *S) const;

/// To be used for checking whether the arguments being passed to
/// function exceeds the number of parameters expected for it.
static bool TooManyArguments(size_t NumParams, size_t NumArgs,
                             bool PartialOverloading = false) {
  // We check whether we're just after a comma in code-completion.
  if (NumArgs > 0 && PartialOverloading)
    return NumArgs + 1 > NumParams; // If so, we view as an extra argument.
  return NumArgs > NumParams;
}

// Emitting members of dllexported classes is delayed until the class
// (including field initializers) is fully parsed.
SmallVector<CXXRecordDecl*, 4> DelayedDllExportClasses;
SmallVector<CXXMethodDecl*, 4> DelayedDllExportMemberFunctions;

12867private:
int ParsingClassDepth = 0;

class SavePendingParsedClassStateRAII {
public:
  SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }

  ~SavePendingParsedClassStateRAII() {
    assert(S.DelayedOverridingExceptionSpecChecks.empty() &&((void)0)
           "there shouldn't be any pending delayed exception spec checks")((void)0);
    assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&((void)0)
           "there shouldn't be any pending delayed exception spec checks")((void)0);
    swapSavedState();
  }

private:
  Sema &S;
  decltype(DelayedOverridingExceptionSpecChecks)
      SavedOverridingExceptionSpecChecks;
  decltype(DelayedEquivalentExceptionSpecChecks)
      SavedEquivalentExceptionSpecChecks;

  void swapSavedState() {
    SavedOverridingExceptionSpecChecks.swap(
        S.DelayedOverridingExceptionSpecChecks);
    SavedEquivalentExceptionSpecChecks.swap(
        S.DelayedEquivalentExceptionSpecChecks);
  }
};

/// Helper class that collects misaligned member designations and
/// their location info for delayed diagnostics.
struct MisalignedMember {
  Expr *E;
  RecordDecl *RD;
  ValueDecl *MD;
  CharUnits Alignment;

  MisalignedMember() : E(), RD(), MD(), Alignment() {}
  MisalignedMember(Expr *E, RecordDecl *RD, ValueDecl *MD,
                   CharUnits Alignment)
      : E(E), RD(RD), MD(MD), Alignment(Alignment) {}
  explicit MisalignedMember(Expr *E)
      : MisalignedMember(E, nullptr, nullptr, CharUnits()) {}

  bool operator==(const MisalignedMember &m) { return this->E == m.E; }
};
/// Small set of gathered accesses to potentially misaligned members
/// due to the packed attribute.
SmallVector<MisalignedMember, 4> MisalignedMembers;

/// Adds an expression to the set of gathered misaligned members.
void AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD, ValueDecl *MD,
                                   CharUnits Alignment);

12922public:
/// Diagnoses the current set of gathered accesses. This typically
/// happens at full expression level. The set is cleared after emitting the
/// diagnostics.
void DiagnoseMisalignedMembers();

/// This function checks if the expression is in the sef of potentially
/// misaligned members and it is converted to some pointer type T with lower
/// or equal alignment requirements. If so it removes it. This is used when
/// we do not want to diagnose such misaligned access (e.g. in conversions to
/// void*).
void DiscardMisalignedMemberAddress(const Type *T, Expr *E);

/// This function calls Action when it determines that E designates a
/// misaligned member due to the packed attribute. This is used to emit
/// local diagnostics like in reference binding.
void RefersToMemberWithReducedAlignment(
    Expr *E,
    llvm::function_ref<void(Expr *, RecordDecl *, FieldDecl *, CharUnits)>
        Action);

/// Describes the reason a calling convention specification was ignored, used
/// for diagnostics.
enum class CallingConventionIgnoredReason {
  ForThisTarget = 0,
  VariadicFunction,
  ConstructorDestructor,
  BuiltinFunction
};
/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurLexicalContext is a kernel function or it is known that the
///   function will be emitted for the device, emits the diagnostics
///   immediately.
/// - If CurLexicalContext is a function and we are compiling
///   for the device, but we don't know that this function will be codegen'ed
///   for devive yet, creates a diagnostic which is emitted if and when we
///   realize that the function will be codegen'ed.
///
/// Example usage:
///
/// Diagnose __float128 type usage only from SYCL device code if the current
/// target doesn't support it
/// if (!S.Context.getTargetInfo().hasFloat128Type() &&
///     S.getLangOpts().SYCLIsDevice)
///   SYCLDiagIfDeviceCode(Loc, diag::err_type_unsupported) << "__float128";
SemaDiagnosticBuilder SYCLDiagIfDeviceCode(SourceLocation Loc,
                                           unsigned DiagID);

/// Check whether we're allowed to call Callee from the current context.
///
/// - If the call is never allowed in a semantically-correct program
///   emits an error and returns false.
///
/// - If the call is allowed in semantically-correct programs, but only if
///   it's never codegen'ed, creates a deferred diagnostic to be emitted if
///   and when the caller is codegen'ed, and returns true.
///
/// - Otherwise, returns true without emitting any diagnostics.
///
/// Adds Callee to DeviceCallGraph if we don't know if its caller will be
/// codegen'ed yet.
bool checkSYCLDeviceFunction(SourceLocation Loc, FunctionDecl *Callee);
12986};

12988/// RAII object that enters a new expression evaluation context.
12989class EnterExpressionEvaluationContext {
Sema &Actions;
bool Entered = true;

12993public:
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Decl *LambdaContextDecl = nullptr,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other,
    bool ShouldEnter = true)
    : Actions(Actions), Entered(ShouldEnter) {
  if (Entered)
    Actions.PushExpressionEvaluationContext(NewContext, LambdaContextDecl,
                                            ExprContext);
}
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Sema::ReuseLambdaContextDecl_t,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other)
    : Actions(Actions) {
  Actions.PushExpressionEvaluationContext(
      NewContext, Sema::ReuseLambdaContextDecl, ExprContext);
}

enum InitListTag { InitList };
EnterExpressionEvaluationContext(Sema &Actions, InitListTag,
                                 bool ShouldEnter = true)
    : Actions(Actions), Entered(false) {
  // In C++11 onwards, narrowing checks are performed on the contents of
  // braced-init-lists, even when they occur within unevaluated operands.
  // Therefore we still need to instantiate constexpr functions used in such
  // a context.
  if (ShouldEnter && Actions.isUnevaluatedContext() &&
      Actions.getLangOpts().CPlusPlus11) {
    Actions.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::UnevaluatedList);
    Entered = true;
  }
}

~EnterExpressionEvaluationContext() {
  if (Entered)
    Actions.PopExpressionEvaluationContext();
}
13035};

13037DeductionFailureInfo
13038MakeDeductionFailureInfo(ASTContext &Context, Sema::TemplateDeductionResult TDK,
                       sema::TemplateDeductionInfo &Info);

13041/// Contains a late templated function.
13042/// Will be parsed at the end of the translation unit, used by Sema & Parser.
13043struct LateParsedTemplate {
CachedTokens Toks;
/// The template function declaration to be late parsed.
Decl *D;
13047};

13049template <>
13050void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
                                               PragmaMsStackAction Action,
                                               llvm::StringRef StackSlotLabel,
                                               AlignPackInfo Value);

13055} // end namespace clang

13057namespace llvm {
13058// Hash a FunctionDeclAndLoc by looking at both its FunctionDecl and its
13059// SourceLocation.
13060template <> struct DenseMapInfo<clang::Sema::FunctionDeclAndLoc> {
using FunctionDeclAndLoc = clang::Sema::FunctionDeclAndLoc;
using FDBaseInfo = DenseMapInfo<clang::CanonicalDeclPtr<clang::FunctionDecl>>;

static FunctionDeclAndLoc getEmptyKey() {
  return {FDBaseInfo::getEmptyKey(), clang::SourceLocation()};
}

static FunctionDeclAndLoc getTombstoneKey() {
  return {FDBaseInfo::getTombstoneKey(), clang::SourceLocation()};
}

static unsigned getHashValue(const FunctionDeclAndLoc &FDL) {
  return hash_combine(FDBaseInfo::getHashValue(FDL.FD),
                      FDL.Loc.getHashValue());
}

static bool isEqual(const FunctionDeclAndLoc &LHS,
                    const FunctionDeclAndLoc &RHS) {
  return LHS.FD == RHS.FD && LHS.Loc == RHS.Loc;
}
13081};
13082} // namespace llvm

13084#endif