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

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaDeclCXX.cpp
Warning:	line 8481, column 7 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 SemaDeclCXX.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/SemaDeclCXX.cpp
1//===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===//
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 implements semantic analysis for C++ declarations.
10//
11//===----------------------------------------------------------------------===//

13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/ASTMutationListener.h"
17#include "clang/AST/CXXInheritance.h"
18#include "clang/AST/CharUnits.h"
19#include "clang/AST/ComparisonCategories.h"
20#include "clang/AST/EvaluatedExprVisitor.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/RecordLayout.h"
23#include "clang/AST/RecursiveASTVisitor.h"
24#include "clang/AST/StmtVisitor.h"
25#include "clang/AST/TypeLoc.h"
26#include "clang/AST/TypeOrdering.h"
27#include "clang/Basic/AttributeCommonInfo.h"
28#include "clang/Basic/PartialDiagnostic.h"
29#include "clang/Basic/TargetInfo.h"
30#include "clang/Lex/LiteralSupport.h"
31#include "clang/Lex/Preprocessor.h"
32#include "clang/Sema/CXXFieldCollector.h"
33#include "clang/Sema/DeclSpec.h"
34#include "clang/Sema/Initialization.h"
35#include "clang/Sema/Lookup.h"
36#include "clang/Sema/ParsedTemplate.h"
37#include "clang/Sema/Scope.h"
38#include "clang/Sema/ScopeInfo.h"
39#include "clang/Sema/SemaInternal.h"
40#include "clang/Sema/Template.h"
41#include "llvm/ADT/ScopeExit.h"
42#include "llvm/ADT/SmallString.h"
43#include "llvm/ADT/STLExtras.h"
44#include "llvm/ADT/StringExtras.h"
45#include <map>
46#include <set>

48using namespace clang;

50//===----------------------------------------------------------------------===//
51// CheckDefaultArgumentVisitor
52//===----------------------------------------------------------------------===//

54namespace {
55/// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses
56/// the default argument of a parameter to determine whether it
57/// contains any ill-formed subexpressions. For example, this will
58/// diagnose the use of local variables or parameters within the
59/// default argument expression.
60class CheckDefaultArgumentVisitor
  : public ConstStmtVisitor<CheckDefaultArgumentVisitor, bool> {
Sema &S;
const Expr *DefaultArg;

65public:
CheckDefaultArgumentVisitor(Sema &S, const Expr *DefaultArg)
    : S(S), DefaultArg(DefaultArg) {}

bool VisitExpr(const Expr *Node);
bool VisitDeclRefExpr(const DeclRefExpr *DRE);
bool VisitCXXThisExpr(const CXXThisExpr *ThisE);
bool VisitLambdaExpr(const LambdaExpr *Lambda);
bool VisitPseudoObjectExpr(const PseudoObjectExpr *POE);
74};

76/// VisitExpr - Visit all of the children of this expression.
77bool CheckDefaultArgumentVisitor::VisitExpr(const Expr *Node) {
bool IsInvalid = false;
for (const Stmt *SubStmt : Node->children())
  IsInvalid |= Visit(SubStmt);
return IsInvalid;
82}

84/// VisitDeclRefExpr - Visit a reference to a declaration, to
85/// determine whether this declaration can be used in the default
86/// argument expression.
87bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(const DeclRefExpr *DRE) {
const NamedDecl *Decl = DRE->getDecl();
if (const auto *Param = dyn_cast<ParmVarDecl>(Decl)) {
  // C++ [dcl.fct.default]p9:
  //   [...] parameters of a function shall not be used in default
  //   argument expressions, even if they are not evaluated. [...]
  //
  // C++17 [dcl.fct.default]p9 (by CWG 2082):
  //   [...] A parameter shall not appear as a potentially-evaluated
  //   expression in a default argument. [...]
  //
  if (DRE->isNonOdrUse() != NOUR_Unevaluated)
    return S.Diag(DRE->getBeginLoc(),
                  diag::err_param_default_argument_references_param)
           << Param->getDeclName() << DefaultArg->getSourceRange();
} else if (const auto *VDecl = dyn_cast<VarDecl>(Decl)) {
  // C++ [dcl.fct.default]p7:
  //   Local variables shall not be used in default argument
  //   expressions.
  //
  // C++17 [dcl.fct.default]p7 (by CWG 2082):
  //   A local variable shall not appear as a potentially-evaluated
  //   expression in a default argument.
  //
  // C++20 [dcl.fct.default]p7 (DR as part of P0588R1, see also CWG 2346):
  //   Note: A local variable cannot be odr-used (6.3) in a default argument.
  //
  if (VDecl->isLocalVarDecl() && !DRE->isNonOdrUse())
    return S.Diag(DRE->getBeginLoc(),
                  diag::err_param_default_argument_references_local)
           << VDecl->getDeclName() << DefaultArg->getSourceRange();
}

return false;
121}

123/// VisitCXXThisExpr - Visit a C++ "this" expression.
124bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(const CXXThisExpr *ThisE) {
// C++ [dcl.fct.default]p8:
//   The keyword this shall not be used in a default argument of a
//   member function.
return S.Diag(ThisE->getBeginLoc(),
              diag::err_param_default_argument_references_this)
       << ThisE->getSourceRange();
131}

133bool CheckDefaultArgumentVisitor::VisitPseudoObjectExpr(
  const PseudoObjectExpr *POE) {
bool Invalid = false;
for (const Expr *E : POE->semantics()) {
  // Look through bindings.
  if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E)) {
    E = OVE->getSourceExpr();
    assert(E && "pseudo-object binding without source expression?")((void)0);
  }

  Invalid |= Visit(E);
}
return Invalid;
146}

148bool CheckDefaultArgumentVisitor::VisitLambdaExpr(const LambdaExpr *Lambda) {
// C++11 [expr.lambda.prim]p13:
//   A lambda-expression appearing in a default argument shall not
//   implicitly or explicitly capture any entity.
if (Lambda->capture_begin() == Lambda->capture_end())
  return false;

return S.Diag(Lambda->getBeginLoc(), diag::err_lambda_capture_default_arg);
156}
157} // namespace

159void
160Sema::ImplicitExceptionSpecification::CalledDecl(SourceLocation CallLoc,
                                               const CXXMethodDecl *Method) {
// If we have an MSAny spec already, don't bother.
if (!Method || ComputedEST == EST_MSAny)
  return;

const FunctionProtoType *Proto
  = Method->getType()->getAs<FunctionProtoType>();
Proto = Self->ResolveExceptionSpec(CallLoc, Proto);
if (!Proto)
  return;

ExceptionSpecificationType EST = Proto->getExceptionSpecType();

// If we have a throw-all spec at this point, ignore the function.
if (ComputedEST == EST_None)
  return;

if (EST == EST_None && Method->hasAttr<NoThrowAttr>())
  EST = EST_BasicNoexcept;

switch (EST) {
case EST_Unparsed:
case EST_Uninstantiated:
case EST_Unevaluated:
  llvm_unreachable("should not see unresolved exception specs here")__builtin_unreachable();

// If this function can throw any exceptions, make a note of that.
case EST_MSAny:
case EST_None:
  // FIXME: Whichever we see last of MSAny and None determines our result.
  // We should make a consistent, order-independent choice here.
  ClearExceptions();
  ComputedEST = EST;
  return;
case EST_NoexceptFalse:
  ClearExceptions();
  ComputedEST = EST_None;
  return;
// FIXME: If the call to this decl is using any of its default arguments, we
// need to search them for potentially-throwing calls.
// If this function has a basic noexcept, it doesn't affect the outcome.
case EST_BasicNoexcept:
case EST_NoexceptTrue:
case EST_NoThrow:
  return;
// If we're still at noexcept(true) and there's a throw() callee,
// change to that specification.
case EST_DynamicNone:
  if (ComputedEST == EST_BasicNoexcept)
    ComputedEST = EST_DynamicNone;
  return;
case EST_DependentNoexcept:
  llvm_unreachable(__builtin_unreachable()
      "should not generate implicit declarations for dependent cases")__builtin_unreachable();
case EST_Dynamic:
  break;
}
assert(EST == EST_Dynamic && "EST case not considered earlier.")((void)0);
assert(ComputedEST != EST_None &&((void)0)
       "Shouldn't collect exceptions when throw-all is guaranteed.")((void)0);
ComputedEST = EST_Dynamic;
// Record the exceptions in this function's exception specification.
for (const auto &E : Proto->exceptions())
  if (ExceptionsSeen.insert(Self->Context.getCanonicalType(E)).second)
    Exceptions.push_back(E);
226}

228void Sema::ImplicitExceptionSpecification::CalledStmt(Stmt *S) {
if (!S || ComputedEST == EST_MSAny)
  return;

// FIXME:
//
// C++0x [except.spec]p14:
//   [An] implicit exception-specification specifies the type-id T if and
// only if T is allowed by the exception-specification of a function directly
// invoked by f's implicit definition; f shall allow all exceptions if any
// function it directly invokes allows all exceptions, and f shall allow no
// exceptions if every function it directly invokes allows no exceptions.
//
// Note in particular that if an implicit exception-specification is generated
// for a function containing a throw-expression, that specification can still
// be noexcept(true).
//
// Note also that 'directly invoked' is not defined in the standard, and there
// is no indication that we should only consider potentially-evaluated calls.
//
// Ultimately we should implement the intent of the standard: the exception
// specification should be the set of exceptions which can be thrown by the
// implicit definition. For now, we assume that any non-nothrow expression can
// throw any exception.

if (Self->canThrow(S))
  ComputedEST = EST_None;
255}

257ExprResult Sema::ConvertParamDefaultArgument(ParmVarDecl *Param, Expr *Arg,
                                           SourceLocation EqualLoc) {
if (RequireCompleteType(Param->getLocation(), Param->getType(),
                        diag::err_typecheck_decl_incomplete_type))
  return true;

// C++ [dcl.fct.default]p5
//   A default argument expression is implicitly converted (clause
//   4) to the parameter type. The default argument expression has
//   the same semantic constraints as the initializer expression in
//   a declaration of a variable of the parameter type, using the
//   copy-initialization semantics (8.5).
InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
                                                                  Param);
InitializationKind Kind = InitializationKind::CreateCopy(Param->getLocation(),
                                                         EqualLoc);
InitializationSequence InitSeq(*this, Entity, Kind, Arg);
ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Arg);
if (Result.isInvalid())
  return true;
Arg = Result.getAs<Expr>();

CheckCompletedExpr(Arg, EqualLoc);
Arg = MaybeCreateExprWithCleanups(Arg);

return Arg;
283}

285void Sema::SetParamDefaultArgument(ParmVarDecl *Param, Expr *Arg,
                                 SourceLocation EqualLoc) {
// Add the default argument to the parameter
Param->setDefaultArg(Arg);

// We have already instantiated this parameter; provide each of the
// instantiations with the uninstantiated default argument.
UnparsedDefaultArgInstantiationsMap::iterator InstPos
  = UnparsedDefaultArgInstantiations.find(Param);
if (InstPos != UnparsedDefaultArgInstantiations.end()) {
  for (unsigned I = 0, N = InstPos->second.size(); I != N; ++I)
    InstPos->second[I]->setUninstantiatedDefaultArg(Arg);

  // We're done tracking this parameter's instantiations.
  UnparsedDefaultArgInstantiations.erase(InstPos);
}
301}

303/// ActOnParamDefaultArgument - Check whether the default argument
304/// provided for a function parameter is well-formed. If so, attach it
305/// to the parameter declaration.
306void
307Sema::ActOnParamDefaultArgument(Decl *param, SourceLocation EqualLoc,
                              Expr *DefaultArg) {
if (!param || !DefaultArg)
  return;

ParmVarDecl *Param = cast<ParmVarDecl>(param);
UnparsedDefaultArgLocs.erase(Param);

auto Fail = [&] {
  Param->setInvalidDecl();
  Param->setDefaultArg(new (Context) OpaqueValueExpr(
      EqualLoc, Param->getType().getNonReferenceType(), VK_PRValue));
};

// Default arguments are only permitted in C++
if (!getLangOpts().CPlusPlus) {
  Diag(EqualLoc, diag::err_param_default_argument)
    << DefaultArg->getSourceRange();
  return Fail();
}

// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(DefaultArg, UPPC_DefaultArgument)) {
  return Fail();
}

// C++11 [dcl.fct.default]p3
//   A default argument expression [...] shall not be specified for a
//   parameter pack.
if (Param->isParameterPack()) {
  Diag(EqualLoc, diag::err_param_default_argument_on_parameter_pack)
      << DefaultArg->getSourceRange();
  // Recover by discarding the default argument.
  Param->setDefaultArg(nullptr);
  return;
}

ExprResult Result = ConvertParamDefaultArgument(Param, DefaultArg, EqualLoc);
if (Result.isInvalid())
  return Fail();

DefaultArg = Result.getAs<Expr>();

// Check that the default argument is well-formed
CheckDefaultArgumentVisitor DefaultArgChecker(*this, DefaultArg);
if (DefaultArgChecker.Visit(DefaultArg))
  return Fail();

SetParamDefaultArgument(Param, DefaultArg, EqualLoc);
356}

358/// ActOnParamUnparsedDefaultArgument - We've seen a default
359/// argument for a function parameter, but we can't parse it yet
360/// because we're inside a class definition. Note that this default
361/// argument will be parsed later.
362void Sema::ActOnParamUnparsedDefaultArgument(Decl *param,
                                           SourceLocation EqualLoc,
                                           SourceLocation ArgLoc) {
if (!param)
  return;

ParmVarDecl *Param = cast<ParmVarDecl>(param);
Param->setUnparsedDefaultArg();
UnparsedDefaultArgLocs[Param] = ArgLoc;
371}

373/// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
374/// the default argument for the parameter param failed.
375void Sema::ActOnParamDefaultArgumentError(Decl *param,
                                        SourceLocation EqualLoc) {
if (!param)
  return;

ParmVarDecl *Param = cast<ParmVarDecl>(param);
Param->setInvalidDecl();
UnparsedDefaultArgLocs.erase(Param);
Param->setDefaultArg(new (Context) OpaqueValueExpr(
    EqualLoc, Param->getType().getNonReferenceType(), VK_PRValue));
385}

387/// CheckExtraCXXDefaultArguments - Check for any extra default
388/// arguments in the declarator, which is not a function declaration
389/// or definition and therefore is not permitted to have default
390/// arguments. This routine should be invoked for every declarator
391/// that is not a function declaration or definition.
392void Sema::CheckExtraCXXDefaultArguments(Declarator &D) {
// C++ [dcl.fct.default]p3
//   A default argument expression shall be specified only in the
//   parameter-declaration-clause of a function declaration or in a
//   template-parameter (14.1). It shall not be specified for a
//   parameter pack. If it is specified in a
//   parameter-declaration-clause, it shall not occur within a
//   declarator or abstract-declarator of a parameter-declaration.
bool MightBeFunction = D.isFunctionDeclarationContext();
for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
  DeclaratorChunk &chunk = D.getTypeObject(i);
  if (chunk.Kind == DeclaratorChunk::Function) {
    if (MightBeFunction) {
      // This is a function declaration. It can have default arguments, but
      // keep looking in case its return type is a function type with default
      // arguments.
      MightBeFunction = false;
      continue;
    }
    for (unsigned argIdx = 0, e = chunk.Fun.NumParams; argIdx != e;
         ++argIdx) {
      ParmVarDecl *Param = cast<ParmVarDecl>(chunk.Fun.Params[argIdx].Param);
      if (Param->hasUnparsedDefaultArg()) {
        std::unique_ptr<CachedTokens> Toks =
            std::move(chunk.Fun.Params[argIdx].DefaultArgTokens);
        SourceRange SR;
        if (Toks->size() > 1)
          SR = SourceRange((*Toks)[1].getLocation(),
                           Toks->back().getLocation());
        else
          SR = UnparsedDefaultArgLocs[Param];
        Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
          << SR;
      } else if (Param->getDefaultArg()) {
        Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
          << Param->getDefaultArg()->getSourceRange();
        Param->setDefaultArg(nullptr);
      }
    }
  } else if (chunk.Kind != DeclaratorChunk::Paren) {
    MightBeFunction = false;
  }
}
435}

437static bool functionDeclHasDefaultArgument(const FunctionDecl *FD) {
return std::any_of(FD->param_begin(), FD->param_end(), [](ParmVarDecl *P) {
  return P->hasDefaultArg() && !P->hasInheritedDefaultArg();
});
441}

443/// MergeCXXFunctionDecl - Merge two declarations of the same C++
444/// function, once we already know that they have the same
445/// type. Subroutine of MergeFunctionDecl. Returns true if there was an
446/// error, false otherwise.
447bool Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old,
                              Scope *S) {
bool Invalid = false;

// The declaration context corresponding to the scope is the semantic
// parent, unless this is a local function declaration, in which case
// it is that surrounding function.
DeclContext *ScopeDC = New->isLocalExternDecl()
                           ? New->getLexicalDeclContext()
                           : New->getDeclContext();

// Find the previous declaration for the purpose of default arguments.
FunctionDecl *PrevForDefaultArgs = Old;
for (/**/; PrevForDefaultArgs;
     // Don't bother looking back past the latest decl if this is a local
     // extern declaration; nothing else could work.
     PrevForDefaultArgs = New->isLocalExternDecl()
                              ? nullptr
                              : PrevForDefaultArgs->getPreviousDecl()) {
  // Ignore hidden declarations.
  if (!LookupResult::isVisible(*this, PrevForDefaultArgs))
    continue;

  if (S && !isDeclInScope(PrevForDefaultArgs, ScopeDC, S) &&
      !New->isCXXClassMember()) {
    // Ignore default arguments of old decl if they are not in
    // the same scope and this is not an out-of-line definition of
    // a member function.
    continue;
  }

  if (PrevForDefaultArgs->isLocalExternDecl() != New->isLocalExternDecl()) {
    // If only one of these is a local function declaration, then they are
    // declared in different scopes, even though isDeclInScope may think
    // they're in the same scope. (If both are local, the scope check is
    // sufficient, and if neither is local, then they are in the same scope.)
    continue;
  }

  // We found the right previous declaration.
  break;
}

// C++ [dcl.fct.default]p4:
//   For non-template functions, default arguments can be added in
//   later declarations of a function in the same
//   scope. Declarations in different scopes have completely
//   distinct sets of default arguments. That is, declarations in
//   inner scopes do not acquire default arguments from
//   declarations in outer scopes, and vice versa. In a given
//   function declaration, all parameters subsequent to a
//   parameter with a default argument shall have default
//   arguments supplied in this or previous declarations. A
//   default argument shall not be redefined by a later
//   declaration (not even to the same value).
//
// C++ [dcl.fct.default]p6:
//   Except for member functions of class templates, the default arguments
//   in a member function definition that appears outside of the class
//   definition are added to the set of default arguments provided by the
//   member function declaration in the class definition.
for (unsigned p = 0, NumParams = PrevForDefaultArgs
                                     ? PrevForDefaultArgs->getNumParams()
                                     : 0;
     p < NumParams; ++p) {
  ParmVarDecl *OldParam = PrevForDefaultArgs->getParamDecl(p);
  ParmVarDecl *NewParam = New->getParamDecl(p);

  bool OldParamHasDfl = OldParam ? OldParam->hasDefaultArg() : false;
  bool NewParamHasDfl = NewParam->hasDefaultArg();

  if (OldParamHasDfl && NewParamHasDfl) {
    unsigned DiagDefaultParamID =
      diag::err_param_default_argument_redefinition;

    // MSVC accepts that default parameters be redefined for member functions
    // of template class. The new default parameter's value is ignored.
    Invalid = true;
    if (getLangOpts().MicrosoftExt) {
      CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(New);
      if (MD && MD->getParent()->getDescribedClassTemplate()) {
        // Merge the old default argument into the new parameter.
        NewParam->setHasInheritedDefaultArg();
        if (OldParam->hasUninstantiatedDefaultArg())
          NewParam->setUninstantiatedDefaultArg(
                                    OldParam->getUninstantiatedDefaultArg());
        else
          NewParam->setDefaultArg(OldParam->getInit());
        DiagDefaultParamID = diag::ext_param_default_argument_redefinition;
        Invalid = false;
      }
    }

    // FIXME: If we knew where the '=' was, we could easily provide a fix-it
    // hint here. Alternatively, we could walk the type-source information
    // for NewParam to find the last source location in the type... but it
    // isn't worth the effort right now. This is the kind of test case that
    // is hard to get right:
    //   int f(int);
    //   void g(int (*fp)(int) = f);
    //   void g(int (*fp)(int) = &f);
    Diag(NewParam->getLocation(), DiagDefaultParamID)
      << NewParam->getDefaultArgRange();

    // Look for the function declaration where the default argument was
    // actually written, which may be a declaration prior to Old.
    for (auto Older = PrevForDefaultArgs;
         OldParam->hasInheritedDefaultArg(); /**/) {
      Older = Older->getPreviousDecl();
      OldParam = Older->getParamDecl(p);
    }

    Diag(OldParam->getLocation(), diag::note_previous_definition)
      << OldParam->getDefaultArgRange();
  } else if (OldParamHasDfl) {
    // Merge the old default argument into the new parameter unless the new
    // function is a friend declaration in a template class. In the latter
    // case the default arguments will be inherited when the friend
    // declaration will be instantiated.
    if (New->getFriendObjectKind() == Decl::FOK_None ||
        !New->getLexicalDeclContext()->isDependentContext()) {
      // It's important to use getInit() here;  getDefaultArg()
      // strips off any top-level ExprWithCleanups.
      NewParam->setHasInheritedDefaultArg();
      if (OldParam->hasUnparsedDefaultArg())
        NewParam->setUnparsedDefaultArg();
      else if (OldParam->hasUninstantiatedDefaultArg())
        NewParam->setUninstantiatedDefaultArg(
                                     OldParam->getUninstantiatedDefaultArg());
      else
        NewParam->setDefaultArg(OldParam->getInit());
    }
  } else if (NewParamHasDfl) {
    if (New->getDescribedFunctionTemplate()) {
      // Paragraph 4, quoted above, only applies to non-template functions.
      Diag(NewParam->getLocation(),
           diag::err_param_default_argument_template_redecl)
        << NewParam->getDefaultArgRange();
      Diag(PrevForDefaultArgs->getLocation(),
           diag::note_template_prev_declaration)
          << false;
    } else if (New->getTemplateSpecializationKind()
                 != TSK_ImplicitInstantiation &&
               New->getTemplateSpecializationKind() != TSK_Undeclared) {
      // C++ [temp.expr.spec]p21:
      //   Default function arguments shall not be specified in a declaration
      //   or a definition for one of the following explicit specializations:
      //     - the explicit specialization of a function template;
      //     - the explicit specialization of a member function template;
      //     - the explicit specialization of a member function of a class
      //       template where the class template specialization to which the
      //       member function specialization belongs is implicitly
      //       instantiated.
      Diag(NewParam->getLocation(), diag::err_template_spec_default_arg)
        << (New->getTemplateSpecializationKind() ==TSK_ExplicitSpecialization)
        << New->getDeclName()
        << NewParam->getDefaultArgRange();
    } else if (New->getDeclContext()->isDependentContext()) {
      // C++ [dcl.fct.default]p6 (DR217):
      //   Default arguments for a member function of a class template shall
      //   be specified on the initial declaration of the member function
      //   within the class template.
      //
      // Reading the tea leaves a bit in DR217 and its reference to DR205
      // leads me to the conclusion that one cannot add default function
      // arguments for an out-of-line definition of a member function of a
      // dependent type.
      int WhichKind = 2;
      if (CXXRecordDecl *Record
            = dyn_cast<CXXRecordDecl>(New->getDeclContext())) {
        if (Record->getDescribedClassTemplate())
          WhichKind = 0;
        else if (isa<ClassTemplatePartialSpecializationDecl>(Record))
          WhichKind = 1;
        else
          WhichKind = 2;
      }

      Diag(NewParam->getLocation(),
           diag::err_param_default_argument_member_template_redecl)
        << WhichKind
        << NewParam->getDefaultArgRange();
    }
  }
}

// DR1344: If a default argument is added outside a class definition and that
// default argument makes the function a special member function, the program
// is ill-formed. This can only happen for constructors.
if (isa<CXXConstructorDecl>(New) &&
    New->getMinRequiredArguments() < Old->getMinRequiredArguments()) {
  CXXSpecialMember NewSM = getSpecialMember(cast<CXXMethodDecl>(New)),
                   OldSM = getSpecialMember(cast<CXXMethodDecl>(Old));
  if (NewSM != OldSM) {
    ParmVarDecl *NewParam = New->getParamDecl(New->getMinRequiredArguments());
    assert(NewParam->hasDefaultArg())((void)0);
    Diag(NewParam->getLocation(), diag::err_default_arg_makes_ctor_special)
      << NewParam->getDefaultArgRange() << NewSM;
    Diag(Old->getLocation(), diag::note_previous_declaration);
  }
}

const FunctionDecl *Def;
// C++11 [dcl.constexpr]p1: If any declaration of a function or function
// template has a constexpr specifier then all its declarations shall
// contain the constexpr specifier.
if (New->getConstexprKind() != Old->getConstexprKind()) {
  Diag(New->getLocation(), diag::err_constexpr_redecl_mismatch)
      << New << static_cast<int>(New->getConstexprKind())
      << static_cast<int>(Old->getConstexprKind());
  Diag(Old->getLocation(), diag::note_previous_declaration);
  Invalid = true;
} else if (!Old->getMostRecentDecl()->isInlined() && New->isInlined() &&
           Old->isDefined(Def) &&
           // If a friend function is inlined but does not have 'inline'
           // specifier, it is a definition. Do not report attribute conflict
           // in this case, redefinition will be diagnosed later.
           (New->isInlineSpecified() ||
            New->getFriendObjectKind() == Decl::FOK_None)) {
  // C++11 [dcl.fcn.spec]p4:
  //   If the definition of a function appears in a translation unit before its
  //   first declaration as inline, the program is ill-formed.
  Diag(New->getLocation(), diag::err_inline_decl_follows_def) << New;
  Diag(Def->getLocation(), diag::note_previous_definition);
  Invalid = true;
}

// C++17 [temp.deduct.guide]p3:
//   Two deduction guide declarations in the same translation unit
//   for the same class template shall not have equivalent
//   parameter-declaration-clauses.
if (isa<CXXDeductionGuideDecl>(New) &&
    !New->isFunctionTemplateSpecialization() && isVisible(Old)) {
  Diag(New->getLocation(), diag::err_deduction_guide_redeclared);
  Diag(Old->getLocation(), diag::note_previous_declaration);
}

// C++11 [dcl.fct.default]p4: If a friend declaration specifies a default
// argument expression, that declaration shall be a definition and shall be
// the only declaration of the function or function template in the
// translation unit.
if (Old->getFriendObjectKind() == Decl::FOK_Undeclared &&
    functionDeclHasDefaultArgument(Old)) {
  Diag(New->getLocation(), diag::err_friend_decl_with_def_arg_redeclared);
  Diag(Old->getLocation(), diag::note_previous_declaration);
  Invalid = true;
}

// C++11 [temp.friend]p4 (DR329):
//   When a function is defined in a friend function declaration in a class
//   template, the function is instantiated when the function is odr-used.
//   The same restrictions on multiple declarations and definitions that
//   apply to non-template function declarations and definitions also apply
//   to these implicit definitions.
const FunctionDecl *OldDefinition = nullptr;
if (New->isThisDeclarationInstantiatedFromAFriendDefinition() &&
    Old->isDefined(OldDefinition, true))
  CheckForFunctionRedefinition(New, OldDefinition);

return Invalid;
707}

709NamedDecl *
710Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,
                                 MultiTemplateParamsArg TemplateParamLists) {
assert(D.isDecompositionDeclarator())((void)0);
const DecompositionDeclarator &Decomp = D.getDecompositionDeclarator();

// The syntax only allows a decomposition declarator as a simple-declaration,
// a for-range-declaration, or a condition in Clang, but we parse it in more
// cases than that.
if (!D.mayHaveDecompositionDeclarator()) {
  Diag(Decomp.getLSquareLoc(), diag::err_decomp_decl_context)
    << Decomp.getSourceRange();
  return nullptr;
}

if (!TemplateParamLists.empty()) {
  // FIXME: There's no rule against this, but there are also no rules that
  // would actually make it usable, so we reject it for now.
  Diag(TemplateParamLists.front()->getTemplateLoc(),
       diag::err_decomp_decl_template);
  return nullptr;
}

Diag(Decomp.getLSquareLoc(),
     !getLangOpts().CPlusPlus17
         ? diag::ext_decomp_decl
         : D.getContext() == DeclaratorContext::Condition
               ? diag::ext_decomp_decl_cond
               : diag::warn_cxx14_compat_decomp_decl)
    << Decomp.getSourceRange();

// The semantic context is always just the current context.
DeclContext *const DC = CurContext;

// C++17 [dcl.dcl]/8:
//   The decl-specifier-seq shall contain only the type-specifier auto
//   and cv-qualifiers.
// C++2a [dcl.dcl]/8:
//   If decl-specifier-seq contains any decl-specifier other than static,
//   thread_local, auto, or cv-qualifiers, the program is ill-formed.
auto &DS = D.getDeclSpec();
{
  SmallVector<StringRef, 8> BadSpecifiers;
  SmallVector<SourceLocation, 8> BadSpecifierLocs;
  SmallVector<StringRef, 8> CPlusPlus20Specifiers;
  SmallVector<SourceLocation, 8> CPlusPlus20SpecifierLocs;
  if (auto SCS = DS.getStorageClassSpec()) {
    if (SCS == DeclSpec::SCS_static) {
      CPlusPlus20Specifiers.push_back(DeclSpec::getSpecifierName(SCS));
      CPlusPlus20SpecifierLocs.push_back(DS.getStorageClassSpecLoc());
    } else {
      BadSpecifiers.push_back(DeclSpec::getSpecifierName(SCS));
      BadSpecifierLocs.push_back(DS.getStorageClassSpecLoc());
    }
  }
  if (auto TSCS = DS.getThreadStorageClassSpec()) {
    CPlusPlus20Specifiers.push_back(DeclSpec::getSpecifierName(TSCS));
    CPlusPlus20SpecifierLocs.push_back(DS.getThreadStorageClassSpecLoc());
  }
  if (DS.hasConstexprSpecifier()) {
    BadSpecifiers.push_back(
        DeclSpec::getSpecifierName(DS.getConstexprSpecifier()));
    BadSpecifierLocs.push_back(DS.getConstexprSpecLoc());
  }
  if (DS.isInlineSpecified()) {
    BadSpecifiers.push_back("inline");
    BadSpecifierLocs.push_back(DS.getInlineSpecLoc());
  }
  if (!BadSpecifiers.empty()) {
    auto &&Err = Diag(BadSpecifierLocs.front(), diag::err_decomp_decl_spec);
    Err << (int)BadSpecifiers.size()
        << llvm::join(BadSpecifiers.begin(), BadSpecifiers.end(), " ");
    // Don't add FixItHints to remove the specifiers; we do still respect
    // them when building the underlying variable.
    for (auto Loc : BadSpecifierLocs)
      Err << SourceRange(Loc, Loc);
  } else if (!CPlusPlus20Specifiers.empty()) {
    auto &&Warn = Diag(CPlusPlus20SpecifierLocs.front(),
                       getLangOpts().CPlusPlus20
                           ? diag::warn_cxx17_compat_decomp_decl_spec
                           : diag::ext_decomp_decl_spec);
    Warn << (int)CPlusPlus20Specifiers.size()
         << llvm::join(CPlusPlus20Specifiers.begin(),
                       CPlusPlus20Specifiers.end(), " ");
    for (auto Loc : CPlusPlus20SpecifierLocs)
      Warn << SourceRange(Loc, Loc);
  }
  // We can't recover from it being declared as a typedef.
  if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef)
    return nullptr;
}

// C++2a [dcl.struct.bind]p1:
//   A cv that includes volatile is deprecated
if ((DS.getTypeQualifiers() & DeclSpec::TQ_volatile) &&
    getLangOpts().CPlusPlus20)
  Diag(DS.getVolatileSpecLoc(),
       diag::warn_deprecated_volatile_structured_binding);

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType R = TInfo->getType();

if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
                                    UPPC_DeclarationType))
  D.setInvalidType();

// The syntax only allows a single ref-qualifier prior to the decomposition
// declarator. No other declarator chunks are permitted. Also check the type
// specifier here.
if (DS.getTypeSpecType() != DeclSpec::TST_auto ||
    D.hasGroupingParens() || D.getNumTypeObjects() > 1 ||
    (D.getNumTypeObjects() == 1 &&
     D.getTypeObject(0).Kind != DeclaratorChunk::Reference)) {
  Diag(Decomp.getLSquareLoc(),
       (D.hasGroupingParens() ||
        (D.getNumTypeObjects() &&
         D.getTypeObject(0).Kind == DeclaratorChunk::Paren))
           ? diag::err_decomp_decl_parens
           : diag::err_decomp_decl_type)
      << R;

  // In most cases, there's no actual problem with an explicitly-specified
  // type, but a function type won't work here, and ActOnVariableDeclarator
  // shouldn't be called for such a type.
  if (R->isFunctionType())
    D.setInvalidType();
}

// Build the BindingDecls.
SmallVector<BindingDecl*, 8> Bindings;

// Build the BindingDecls.
for (auto &B : D.getDecompositionDeclarator().bindings()) {
  // Check for name conflicts.
  DeclarationNameInfo NameInfo(B.Name, B.NameLoc);
  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
                        ForVisibleRedeclaration);
  LookupName(Previous, S,
             /*CreateBuiltins*/DC->getRedeclContext()->isTranslationUnit());

  // It's not permitted to shadow a template parameter name.
  if (Previous.isSingleResult() &&
      Previous.getFoundDecl()->isTemplateParameter()) {
    DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
                                    Previous.getFoundDecl());
    Previous.clear();
  }

  auto *BD = BindingDecl::Create(Context, DC, B.NameLoc, B.Name);

  // Find the shadowed declaration before filtering for scope.
  NamedDecl *ShadowedDecl = D.getCXXScopeSpec().isEmpty()
                                ? getShadowedDeclaration(BD, Previous)
                                : nullptr;

  bool ConsiderLinkage = DC->isFunctionOrMethod() &&
                         DS.getStorageClassSpec() == DeclSpec::SCS_extern;
  FilterLookupForScope(Previous, DC, S, ConsiderLinkage,
                       /*AllowInlineNamespace*/false);

  if (!Previous.empty()) {
    auto *Old = Previous.getRepresentativeDecl();
    Diag(B.NameLoc, diag::err_redefinition) << B.Name;
    Diag(Old->getLocation(), diag::note_previous_definition);
  } else if (ShadowedDecl && !D.isRedeclaration()) {
    CheckShadow(BD, ShadowedDecl, Previous);
  }
  PushOnScopeChains(BD, S, true);
  Bindings.push_back(BD);
  ParsingInitForAutoVars.insert(BD);
}

// There are no prior lookup results for the variable itself, because it
// is unnamed.
DeclarationNameInfo NameInfo((IdentifierInfo *)nullptr,
                             Decomp.getLSquareLoc());
LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
                      ForVisibleRedeclaration);

// Build the variable that holds the non-decomposed object.
bool AddToScope = true;
NamedDecl *New =
    ActOnVariableDeclarator(S, D, DC, TInfo, Previous,
                            MultiTemplateParamsArg(), AddToScope, Bindings);
if (AddToScope) {
  S->AddDecl(New);
  CurContext->addHiddenDecl(New);
}

if (isInOpenMPDeclareTargetContext())
  checkDeclIsAllowedInOpenMPTarget(nullptr, New);

return New;
902}

904static bool checkSimpleDecomposition(
  Sema &S, ArrayRef<BindingDecl *> Bindings, ValueDecl *Src,
  QualType DecompType, const llvm::APSInt &NumElems, QualType ElemType,
  llvm::function_ref<ExprResult(SourceLocation, Expr *, unsigned)> GetInit) {
if ((int64_t)Bindings.size() != NumElems) {
  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
      << DecompType << (unsigned)Bindings.size()
      << (unsigned)NumElems.getLimitedValue(UINT_MAX(2147483647 *2U +1U))
      << toString(NumElems, 10) << (NumElems < Bindings.size());
  return true;
}

unsigned I = 0;
for (auto *B : Bindings) {
  SourceLocation Loc = B->getLocation();
  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
  if (E.isInvalid())
    return true;
  E = GetInit(Loc, E.get(), I++);
  if (E.isInvalid())
    return true;
  B->setBinding(ElemType, E.get());
}

return false;
929}

931static bool checkArrayLikeDecomposition(Sema &S,
                                      ArrayRef<BindingDecl *> Bindings,
                                      ValueDecl *Src, QualType DecompType,
                                      const llvm::APSInt &NumElems,
                                      QualType ElemType) {
return checkSimpleDecomposition(
    S, Bindings, Src, DecompType, NumElems, ElemType,
    [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
      ExprResult E = S.ActOnIntegerConstant(Loc, I);
      if (E.isInvalid())
        return ExprError();
      return S.CreateBuiltinArraySubscriptExpr(Base, Loc, E.get(), Loc);
    });
944}

946static bool checkArrayDecomposition(Sema &S, ArrayRef<BindingDecl*> Bindings,
                                  ValueDecl *Src, QualType DecompType,
                                  const ConstantArrayType *CAT) {
return checkArrayLikeDecomposition(S, Bindings, Src, DecompType,
                                   llvm::APSInt(CAT->getSize()),
                                   CAT->getElementType());
952}

954static bool checkVectorDecomposition(Sema &S, ArrayRef<BindingDecl*> Bindings,
                                   ValueDecl *Src, QualType DecompType,
                                   const VectorType *VT) {
return checkArrayLikeDecomposition(
    S, Bindings, Src, DecompType, llvm::APSInt::get(VT->getNumElements()),
    S.Context.getQualifiedType(VT->getElementType(),
                               DecompType.getQualifiers()));
961}

963static bool checkComplexDecomposition(Sema &S,
                                    ArrayRef<BindingDecl *> Bindings,
                                    ValueDecl *Src, QualType DecompType,
                                    const ComplexType *CT) {
return checkSimpleDecomposition(
    S, Bindings, Src, DecompType, llvm::APSInt::get(2),
    S.Context.getQualifiedType(CT->getElementType(),
                               DecompType.getQualifiers()),
    [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
      return S.CreateBuiltinUnaryOp(Loc, I ? UO_Imag : UO_Real, Base);
    });
974}

976static std::string printTemplateArgs(const PrintingPolicy &PrintingPolicy,
                                   TemplateArgumentListInfo &Args,
                                   const TemplateParameterList *Params) {
SmallString<128> SS;
llvm::raw_svector_ostream OS(SS);
bool First = true;
unsigned I = 0;
for (auto &Arg : Args.arguments()) {
  if (!First)
    OS << ", ";
  Arg.getArgument().print(
      PrintingPolicy, OS,
      TemplateParameterList::shouldIncludeTypeForArgument(Params, I));
  First = false;
  I++;
}
return std::string(OS.str());
993}

995static bool lookupStdTypeTraitMember(Sema &S, LookupResult &TraitMemberLookup,
                                   SourceLocation Loc, StringRef Trait,
                                   TemplateArgumentListInfo &Args,
                                   unsigned DiagID) {
auto DiagnoseMissing = [&] {
  if (DiagID)
    S.Diag(Loc, DiagID) << printTemplateArgs(S.Context.getPrintingPolicy(),
                                             Args, /*Params*/ nullptr);
  return true;
};

// FIXME: Factor out duplication with lookupPromiseType in SemaCoroutine.
NamespaceDecl *Std = S.getStdNamespace();
if (!Std)
  return DiagnoseMissing();

// Look up the trait itself, within namespace std. We can diagnose various
// problems with this lookup even if we've been asked to not diagnose a
// missing specialization, because this can only fail if the user has been
// declaring their own names in namespace std or we don't support the
// standard library implementation in use.
LookupResult Result(S, &S.PP.getIdentifierTable().get(Trait),
                    Loc, Sema::LookupOrdinaryName);
if (!S.LookupQualifiedName(Result, Std))
  return DiagnoseMissing();
if (Result.isAmbiguous())
  return true;

ClassTemplateDecl *TraitTD = Result.getAsSingle<ClassTemplateDecl>();
if (!TraitTD) {
  Result.suppressDiagnostics();
  NamedDecl *Found = *Result.begin();
  S.Diag(Loc, diag::err_std_type_trait_not_class_template) << Trait;
  S.Diag(Found->getLocation(), diag::note_declared_at);
  return true;
}

// Build the template-id.
QualType TraitTy = S.CheckTemplateIdType(TemplateName(TraitTD), Loc, Args);
if (TraitTy.isNull())
  return true;
if (!S.isCompleteType(Loc, TraitTy)) {
  if (DiagID)
    S.RequireCompleteType(
        Loc, TraitTy, DiagID,
        printTemplateArgs(S.Context.getPrintingPolicy(), Args,
                          TraitTD->getTemplateParameters()));
  return true;
}

CXXRecordDecl *RD = TraitTy->getAsCXXRecordDecl();
assert(RD && "specialization of class template is not a class?")((void)0);

// Look up the member of the trait type.
S.LookupQualifiedName(TraitMemberLookup, RD);
return TraitMemberLookup.isAmbiguous();
1051}

1053static TemplateArgumentLoc
1054getTrivialIntegralTemplateArgument(Sema &S, SourceLocation Loc, QualType T,
                                 uint64_t I) {
TemplateArgument Arg(S.Context, S.Context.MakeIntValue(I, T), T);
return S.getTrivialTemplateArgumentLoc(Arg, T, Loc);
1058}

1060static TemplateArgumentLoc
1061getTrivialTypeTemplateArgument(Sema &S, SourceLocation Loc, QualType T) {
return S.getTrivialTemplateArgumentLoc(TemplateArgument(T), QualType(), Loc);
1063}

1065namespace { enum class IsTupleLike { TupleLike, NotTupleLike, Error }; }

1067static IsTupleLike isTupleLike(Sema &S, SourceLocation Loc, QualType T,
                             llvm::APSInt &Size) {
EnterExpressionEvaluationContext ContextRAII(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

DeclarationName Value = S.PP.getIdentifierInfo("value");
LookupResult R(S, Value, Loc, Sema::LookupOrdinaryName);

// Form template argument list for tuple_size<T>.
TemplateArgumentListInfo Args(Loc, Loc);
Args.addArgument(getTrivialTypeTemplateArgument(S, Loc, T));

// If there's no tuple_size specialization or the lookup of 'value' is empty,
// it's not tuple-like.
if (lookupStdTypeTraitMember(S, R, Loc, "tuple_size", Args, /*DiagID*/ 0) ||
    R.empty())
  return IsTupleLike::NotTupleLike;

// If we get this far, we've committed to the tuple interpretation, but
// we can still fail if there actually isn't a usable ::value.

struct ICEDiagnoser : Sema::VerifyICEDiagnoser {
  LookupResult &R;
  TemplateArgumentListInfo &Args;
  ICEDiagnoser(LookupResult &R, TemplateArgumentListInfo &Args)
      : R(R), Args(Args) {}
  Sema::SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
                                             SourceLocation Loc) override {
    return S.Diag(Loc, diag::err_decomp_decl_std_tuple_size_not_constant)
           << printTemplateArgs(S.Context.getPrintingPolicy(), Args,
                                /*Params*/ nullptr);
  }
} Diagnoser(R, Args);

ExprResult E =
    S.BuildDeclarationNameExpr(CXXScopeSpec(), R, /*NeedsADL*/false);
if (E.isInvalid())
  return IsTupleLike::Error;

E = S.VerifyIntegerConstantExpression(E.get(), &Size, Diagnoser);
if (E.isInvalid())
  return IsTupleLike::Error;

return IsTupleLike::TupleLike;
1111}

1113/// \return std::tuple_element<I, T>::type.
1114static QualType getTupleLikeElementType(Sema &S, SourceLocation Loc,
                                      unsigned I, QualType T) {
// Form template argument list for tuple_element<I, T>.
TemplateArgumentListInfo Args(Loc, Loc);
Args.addArgument(
    getTrivialIntegralTemplateArgument(S, Loc, S.Context.getSizeType(), I));
Args.addArgument(getTrivialTypeTemplateArgument(S, Loc, T));

DeclarationName TypeDN = S.PP.getIdentifierInfo("type");
LookupResult R(S, TypeDN, Loc, Sema::LookupOrdinaryName);
if (lookupStdTypeTraitMember(
        S, R, Loc, "tuple_element", Args,
        diag::err_decomp_decl_std_tuple_element_not_specialized))
  return QualType();

auto *TD = R.getAsSingle<TypeDecl>();
if (!TD) {
  R.suppressDiagnostics();
  S.Diag(Loc, diag::err_decomp_decl_std_tuple_element_not_specialized)
      << printTemplateArgs(S.Context.getPrintingPolicy(), Args,
                           /*Params*/ nullptr);
  if (!R.empty())
    S.Diag(R.getRepresentativeDecl()->getLocation(), diag::note_declared_at);
  return QualType();
}

return S.Context.getTypeDeclType(TD);
1141}

1143namespace {
1144struct InitializingBinding {
Sema &S;
InitializingBinding(Sema &S, BindingDecl *BD) : S(S) {
  Sema::CodeSynthesisContext Ctx;
  Ctx.Kind = Sema::CodeSynthesisContext::InitializingStructuredBinding;
  Ctx.PointOfInstantiation = BD->getLocation();
  Ctx.Entity = BD;
  S.pushCodeSynthesisContext(Ctx);
}
~InitializingBinding() {
  S.popCodeSynthesisContext();
}
1156};
1157}

1159static bool checkTupleLikeDecomposition(Sema &S,
                                      ArrayRef<BindingDecl *> Bindings,
                                      VarDecl *Src, QualType DecompType,
                                      const llvm::APSInt &TupleSize) {
if ((int64_t)Bindings.size() != TupleSize) {
  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
      << DecompType << (unsigned)Bindings.size()
      << (unsigned)TupleSize.getLimitedValue(UINT_MAX(2147483647 *2U +1U))
      << toString(TupleSize, 10) << (TupleSize < Bindings.size());
  return true;
}

if (Bindings.empty())
  return false;

DeclarationName GetDN = S.PP.getIdentifierInfo("get");

// [dcl.decomp]p3:
//   The unqualified-id get is looked up in the scope of E by class member
//   access lookup ...
LookupResult MemberGet(S, GetDN, Src->getLocation(), Sema::LookupMemberName);
bool UseMemberGet = false;
if (S.isCompleteType(Src->getLocation(), DecompType)) {
  if (auto *RD = DecompType->getAsCXXRecordDecl())
    S.LookupQualifiedName(MemberGet, RD);
  if (MemberGet.isAmbiguous())
    return true;
  //   ... and if that finds at least one declaration that is a function
  //   template whose first template parameter is a non-type parameter ...
  for (NamedDecl *D : MemberGet) {
    if (FunctionTemplateDecl *FTD =
            dyn_cast<FunctionTemplateDecl>(D->getUnderlyingDecl())) {
      TemplateParameterList *TPL = FTD->getTemplateParameters();
      if (TPL->size() != 0 &&
          isa<NonTypeTemplateParmDecl>(TPL->getParam(0))) {
        //   ... the initializer is e.get<i>().
        UseMemberGet = true;
        break;
      }
    }
  }
}

unsigned I = 0;
for (auto *B : Bindings) {
  InitializingBinding InitContext(S, B);
  SourceLocation Loc = B->getLocation();

  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
  if (E.isInvalid())
    return true;

  //   e is an lvalue if the type of the entity is an lvalue reference and
  //   an xvalue otherwise
  if (!Src->getType()->isLValueReferenceType())
    E = ImplicitCastExpr::Create(S.Context, E.get()->getType(), CK_NoOp,
                                 E.get(), nullptr, VK_XValue,
                                 FPOptionsOverride());

  TemplateArgumentListInfo Args(Loc, Loc);
  Args.addArgument(
      getTrivialIntegralTemplateArgument(S, Loc, S.Context.getSizeType(), I));

  if (UseMemberGet) {
    //   if [lookup of member get] finds at least one declaration, the
    //   initializer is e.get<i-1>().
    E = S.BuildMemberReferenceExpr(E.get(), DecompType, Loc, false,
                                   CXXScopeSpec(), SourceLocation(), nullptr,
                                   MemberGet, &Args, nullptr);
    if (E.isInvalid())
      return true;

    E = S.BuildCallExpr(nullptr, E.get(), Loc, None, Loc);
  } else {
    //   Otherwise, the initializer is get<i-1>(e), where get is looked up
    //   in the associated namespaces.
    Expr *Get = UnresolvedLookupExpr::Create(
        S.Context, nullptr, NestedNameSpecifierLoc(), SourceLocation(),
        DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/true, &Args,
        UnresolvedSetIterator(), UnresolvedSetIterator());

    Expr *Arg = E.get();
    E = S.BuildCallExpr(nullptr, Get, Loc, Arg, Loc);
  }
  if (E.isInvalid())
    return true;
  Expr *Init = E.get();

  //   Given the type T designated by std::tuple_element<i - 1, E>::type,
  QualType T = getTupleLikeElementType(S, Loc, I, DecompType);
  if (T.isNull())
    return true;

  //   each vi is a variable of type "reference to T" initialized with the
  //   initializer, where the reference is an lvalue reference if the
  //   initializer is an lvalue and an rvalue reference otherwise
  QualType RefType =
      S.BuildReferenceType(T, E.get()->isLValue(), Loc, B->getDeclName());
  if (RefType.isNull())
    return true;
  auto *RefVD = VarDecl::Create(
      S.Context, Src->getDeclContext(), Loc, Loc,
      B->getDeclName().getAsIdentifierInfo(), RefType,
      S.Context.getTrivialTypeSourceInfo(T, Loc), Src->getStorageClass());
  RefVD->setLexicalDeclContext(Src->getLexicalDeclContext());
  RefVD->setTSCSpec(Src->getTSCSpec());
  RefVD->setImplicit();
  if (Src->isInlineSpecified())
    RefVD->setInlineSpecified();
  RefVD->getLexicalDeclContext()->addHiddenDecl(RefVD);

  InitializedEntity Entity = InitializedEntity::InitializeBinding(RefVD);
  InitializationKind Kind = InitializationKind::CreateCopy(Loc, Loc);
  InitializationSequence Seq(S, Entity, Kind, Init);
  E = Seq.Perform(S, Entity, Kind, Init);
  if (E.isInvalid())
    return true;
  E = S.ActOnFinishFullExpr(E.get(), Loc, /*DiscardedValue*/ false);
  if (E.isInvalid())
    return true;
  RefVD->setInit(E.get());
  S.CheckCompleteVariableDeclaration(RefVD);

  E = S.BuildDeclarationNameExpr(CXXScopeSpec(),
                                 DeclarationNameInfo(B->getDeclName(), Loc),
                                 RefVD);
  if (E.isInvalid())
    return true;

  B->setBinding(T, E.get());
  I++;
}

return false;
1293}

1295/// Find the base class to decompose in a built-in decomposition of a class type.
1296/// This base class search is, unfortunately, not quite like any other that we
1297/// perform anywhere else in C++.
1298static DeclAccessPair findDecomposableBaseClass(Sema &S, SourceLocation Loc,
                                              const CXXRecordDecl *RD,
                                              CXXCastPath &BasePath) {
auto BaseHasFields = [](const CXXBaseSpecifier *Specifier,
                        CXXBasePath &Path) {
  return Specifier->getType()->getAsCXXRecordDecl()->hasDirectFields();
};

const CXXRecordDecl *ClassWithFields = nullptr;
AccessSpecifier AS = AS_public;
if (RD->hasDirectFields())
  // [dcl.decomp]p4:
  //   Otherwise, all of E's non-static data members shall be public direct
  //   members of E ...
  ClassWithFields = RD;
else {
  //   ... or of ...
  CXXBasePaths Paths;
  Paths.setOrigin(const_cast<CXXRecordDecl*>(RD));
  if (!RD->lookupInBases(BaseHasFields, Paths)) {
    // If no classes have fields, just decompose RD itself. (This will work
    // if and only if zero bindings were provided.)
    return DeclAccessPair::make(const_cast<CXXRecordDecl*>(RD), AS_public);
  }

  CXXBasePath *BestPath = nullptr;
  for (auto &P : Paths) {
    if (!BestPath)
      BestPath = &P;
    else if (!S.Context.hasSameType(P.back().Base->getType(),
                                    BestPath->back().Base->getType())) {
      //   ... the same ...
      S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
        << false << RD << BestPath->back().Base->getType()
        << P.back().Base->getType();
      return DeclAccessPair();
    } else if (P.Access < BestPath->Access) {
      BestPath = &P;
    }
  }

  //   ... unambiguous ...
  QualType BaseType = BestPath->back().Base->getType();
  if (Paths.isAmbiguous(S.Context.getCanonicalType(BaseType))) {
    S.Diag(Loc, diag::err_decomp_decl_ambiguous_base)
      << RD << BaseType << S.getAmbiguousPathsDisplayString(Paths);
    return DeclAccessPair();
  }

  //   ... [accessible, implied by other rules] base class of E.
  S.CheckBaseClassAccess(Loc, BaseType, S.Context.getRecordType(RD),
                         *BestPath, diag::err_decomp_decl_inaccessible_base);
  AS = BestPath->Access;

  ClassWithFields = BaseType->getAsCXXRecordDecl();
  S.BuildBasePathArray(Paths, BasePath);
}

// The above search did not check whether the selected class itself has base
// classes with fields, so check that now.
CXXBasePaths Paths;
if (ClassWithFields->lookupInBases(BaseHasFields, Paths)) {
  S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
    << (ClassWithFields == RD) << RD << ClassWithFields
    << Paths.front().back().Base->getType();
  return DeclAccessPair();
}

return DeclAccessPair::make(const_cast<CXXRecordDecl*>(ClassWithFields), AS);
1367}

1369static bool checkMemberDecomposition(Sema &S, ArrayRef<BindingDecl*> Bindings,
                                   ValueDecl *Src, QualType DecompType,
                                   const CXXRecordDecl *OrigRD) {
if (S.RequireCompleteType(Src->getLocation(), DecompType,
                          diag::err_incomplete_type))
  return true;

CXXCastPath BasePath;
DeclAccessPair BasePair =
    findDecomposableBaseClass(S, Src->getLocation(), OrigRD, BasePath);
const CXXRecordDecl *RD = cast_or_null<CXXRecordDecl>(BasePair.getDecl());
if (!RD)
  return true;
QualType BaseType = S.Context.getQualifiedType(S.Context.getRecordType(RD),
                                               DecompType.getQualifiers());

auto DiagnoseBadNumberOfBindings = [&]() -> bool {
  unsigned NumFields =
      std::count_if(RD->field_begin(), RD->field_end(),
                    [](FieldDecl *FD) { return !FD->isUnnamedBitfield(); });
  assert(Bindings.size() != NumFields)((void)0);
  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
      << DecompType << (unsigned)Bindings.size() << NumFields << NumFields
      << (NumFields < Bindings.size());
  return true;
};

//   all of E's non-static data members shall be [...] well-formed
//   when named as e.name in the context of the structured binding,
//   E shall not have an anonymous union member, ...
unsigned I = 0;
for (auto *FD : RD->fields()) {
  if (FD->isUnnamedBitfield())
    continue;

  // All the non-static data members are required to be nameable, so they
  // must all have names.
  if (!FD->getDeclName()) {
    if (RD->isLambda()) {
      S.Diag(Src->getLocation(), diag::err_decomp_decl_lambda);
      S.Diag(RD->getLocation(), diag::note_lambda_decl);
      return true;
    }

    if (FD->isAnonymousStructOrUnion()) {
      S.Diag(Src->getLocation(), diag::err_decomp_decl_anon_union_member)
        << DecompType << FD->getType()->isUnionType();
      S.Diag(FD->getLocation(), diag::note_declared_at);
      return true;
    }

    // FIXME: Are there any other ways we could have an anonymous member?
  }

  // We have a real field to bind.
  if (I >= Bindings.size())
    return DiagnoseBadNumberOfBindings();
  auto *B = Bindings[I++];
  SourceLocation Loc = B->getLocation();

  // The field must be accessible in the context of the structured binding.
  // We already checked that the base class is accessible.
  // FIXME: Add 'const' to AccessedEntity's classes so we can remove the
  // const_cast here.
  S.CheckStructuredBindingMemberAccess(
      Loc, const_cast<CXXRecordDecl *>(OrigRD),
      DeclAccessPair::make(FD, CXXRecordDecl::MergeAccess(
                                   BasePair.getAccess(), FD->getAccess())));

  // Initialize the binding to Src.FD.
  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
  if (E.isInvalid())
    return true;
  E = S.ImpCastExprToType(E.get(), BaseType, CK_UncheckedDerivedToBase,
                          VK_LValue, &BasePath);
  if (E.isInvalid())
    return true;
  E = S.BuildFieldReferenceExpr(E.get(), /*IsArrow*/ false, Loc,
                                CXXScopeSpec(), FD,
                                DeclAccessPair::make(FD, FD->getAccess()),
                                DeclarationNameInfo(FD->getDeclName(), Loc));
  if (E.isInvalid())
    return true;

  // If the type of the member is T, the referenced type is cv T, where cv is
  // the cv-qualification of the decomposition expression.
  //
  // FIXME: We resolve a defect here: if the field is mutable, we do not add
  // 'const' to the type of the field.
  Qualifiers Q = DecompType.getQualifiers();
  if (FD->isMutable())
    Q.removeConst();
  B->setBinding(S.BuildQualifiedType(FD->getType(), Loc, Q), E.get());
}

if (I != Bindings.size())
  return DiagnoseBadNumberOfBindings();

return false;
1468}

1470void Sema::CheckCompleteDecompositionDeclaration(DecompositionDecl *DD) {
QualType DecompType = DD->getType();

// If the type of the decomposition is dependent, then so is the type of
// each binding.
if (DecompType->isDependentType()) {
  for (auto *B : DD->bindings())
    B->setType(Context.DependentTy);
  return;
}

DecompType = DecompType.getNonReferenceType();
ArrayRef<BindingDecl*> Bindings = DD->bindings();

// C++1z [dcl.decomp]/2:
//   If E is an array type [...]
// As an extension, we also support decomposition of built-in complex and
// vector types.
if (auto *CAT = Context.getAsConstantArrayType(DecompType)) {
  if (checkArrayDecomposition(*this, Bindings, DD, DecompType, CAT))
    DD->setInvalidDecl();
  return;
}
if (auto *VT = DecompType->getAs<VectorType>()) {
  if (checkVectorDecomposition(*this, Bindings, DD, DecompType, VT))
    DD->setInvalidDecl();
  return;
}
if (auto *CT = DecompType->getAs<ComplexType>()) {
  if (checkComplexDecomposition(*this, Bindings, DD, DecompType, CT))
    DD->setInvalidDecl();
  return;
}

// C++1z [dcl.decomp]/3:
//   if the expression std::tuple_size<E>::value is a well-formed integral
//   constant expression, [...]
llvm::APSInt TupleSize(32);
switch (isTupleLike(*this, DD->getLocation(), DecompType, TupleSize)) {
case IsTupleLike::Error:
  DD->setInvalidDecl();
  return;

case IsTupleLike::TupleLike:
  if (checkTupleLikeDecomposition(*this, Bindings, DD, DecompType, TupleSize))
    DD->setInvalidDecl();
  return;

case IsTupleLike::NotTupleLike:
  break;
}

// C++1z [dcl.dcl]/8:
//   [E shall be of array or non-union class type]
CXXRecordDecl *RD = DecompType->getAsCXXRecordDecl();
if (!RD || RD->isUnion()) {
  Diag(DD->getLocation(), diag::err_decomp_decl_unbindable_type)
      << DD << !RD << DecompType;
  DD->setInvalidDecl();
  return;
}

// C++1z [dcl.decomp]/4:
//   all of E's non-static data members shall be [...] direct members of
//   E or of the same unambiguous public base class of E, ...
if (checkMemberDecomposition(*this, Bindings, DD, DecompType, RD))
  DD->setInvalidDecl();
1537}

1539/// Merge the exception specifications of two variable declarations.
1540///
1541/// This is called when there's a redeclaration of a VarDecl. The function
1542/// checks if the redeclaration might have an exception specification and
1543/// validates compatibility and merges the specs if necessary.
1544void Sema::MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old) {
// Shortcut if exceptions are disabled.
if (!getLangOpts().CXXExceptions)
  return;

assert(Context.hasSameType(New->getType(), Old->getType()) &&((void)0)
       "Should only be called if types are otherwise the same.")((void)0);

QualType NewType = New->getType();
QualType OldType = Old->getType();

// We're only interested in pointers and references to functions, as well
// as pointers to member functions.
if (const ReferenceType *R = NewType->getAs<ReferenceType>()) {
  NewType = R->getPointeeType();
  OldType = OldType->castAs<ReferenceType>()->getPointeeType();
} else if (const PointerType *P = NewType->getAs<PointerType>()) {
  NewType = P->getPointeeType();
  OldType = OldType->castAs<PointerType>()->getPointeeType();
} else if (const MemberPointerType *M = NewType->getAs<MemberPointerType>()) {
  NewType = M->getPointeeType();
  OldType = OldType->castAs<MemberPointerType>()->getPointeeType();
}

if (!NewType->isFunctionProtoType())
  return;

// There's lots of special cases for functions. For function pointers, system
// libraries are hopefully not as broken so that we don't need these
// workarounds.
if (CheckEquivalentExceptionSpec(
      OldType->getAs<FunctionProtoType>(), Old->getLocation(),
      NewType->getAs<FunctionProtoType>(), New->getLocation())) {
  New->setInvalidDecl();
}
1579}

1581/// CheckCXXDefaultArguments - Verify that the default arguments for a
1582/// function declaration are well-formed according to C++
1583/// [dcl.fct.default].
1584void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) {
unsigned NumParams = FD->getNumParams();
unsigned ParamIdx = 0;

// This checking doesn't make sense for explicit specializations; their
// default arguments are determined by the declaration we're specializing,
// not by FD.
if (FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
  return;
if (auto *FTD = FD->getDescribedFunctionTemplate())
  if (FTD->isMemberSpecialization())
    return;

// Find first parameter with a default argument
for (; ParamIdx < NumParams; ++ParamIdx) {
  ParmVarDecl *Param = FD->getParamDecl(ParamIdx);
  if (Param->hasDefaultArg())
    break;
}

// C++20 [dcl.fct.default]p4:
//   In a given function declaration, each parameter subsequent to a parameter
//   with a default argument shall have a default argument supplied in this or
//   a previous declaration, unless the parameter was expanded from a
//   parameter pack, or shall be a function parameter pack.
for (; ParamIdx < NumParams; ++ParamIdx) {
  ParmVarDecl *Param = FD->getParamDecl(ParamIdx);
  if (!Param->hasDefaultArg() && !Param->isParameterPack() &&
      !(CurrentInstantiationScope &&
        CurrentInstantiationScope->isLocalPackExpansion(Param))) {
    if (Param->isInvalidDecl())
      /* We already complained about this parameter. */;
    else if (Param->getIdentifier())
      Diag(Param->getLocation(),
           diag::err_param_default_argument_missing_name)
        << Param->getIdentifier();
    else
      Diag(Param->getLocation(),
           diag::err_param_default_argument_missing);
  }
}
1625}

1627/// Check that the given type is a literal type. Issue a diagnostic if not,
1628/// if Kind is Diagnose.
1629/// \return \c true if a problem has been found (and optionally diagnosed).
1630template <typename... Ts>
1631static bool CheckLiteralType(Sema &SemaRef, Sema::CheckConstexprKind Kind,
                           SourceLocation Loc, QualType T, unsigned DiagID,
                           Ts &&...DiagArgs) {
if (T->isDependentType())
  return false;

switch (Kind) {
case Sema::CheckConstexprKind::Diagnose:
  return SemaRef.RequireLiteralType(Loc, T, DiagID,
                                    std::forward<Ts>(DiagArgs)...);

case Sema::CheckConstexprKind::CheckValid:
  return !T->isLiteralType(SemaRef.Context);
}

llvm_unreachable("unknown CheckConstexprKind")__builtin_unreachable();
1647}

1649/// Determine whether a destructor cannot be constexpr due to
1650static bool CheckConstexprDestructorSubobjects(Sema &SemaRef,
                                             const CXXDestructorDecl *DD,
                                             Sema::CheckConstexprKind Kind) {
auto Check = [&](SourceLocation Loc, QualType T, const FieldDecl *FD) {
  const CXXRecordDecl *RD =
      T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
  if (!RD || RD->hasConstexprDestructor())
    return true;

  if (Kind == Sema::CheckConstexprKind::Diagnose) {
    SemaRef.Diag(DD->getLocation(), diag::err_constexpr_dtor_subobject)
        << static_cast<int>(DD->getConstexprKind()) << !FD
        << (FD ? FD->getDeclName() : DeclarationName()) << T;
    SemaRef.Diag(Loc, diag::note_constexpr_dtor_subobject)
        << !FD << (FD ? FD->getDeclName() : DeclarationName()) << T;
  }
  return false;
};

const CXXRecordDecl *RD = DD->getParent();
for (const CXXBaseSpecifier &B : RD->bases())
  if (!Check(B.getBaseTypeLoc(), B.getType(), nullptr))
    return false;
for (const FieldDecl *FD : RD->fields())
  if (!Check(FD->getLocation(), FD->getType(), FD))
    return false;
return true;
1677}

1679/// Check whether a function's parameter types are all literal types. If so,
1680/// return true. If not, produce a suitable diagnostic and return false.
1681static bool CheckConstexprParameterTypes(Sema &SemaRef,
                                       const FunctionDecl *FD,
                                       Sema::CheckConstexprKind Kind) {
unsigned ArgIndex = 0;
const auto *FT = FD->getType()->castAs<FunctionProtoType>();
for (FunctionProtoType::param_type_iterator i = FT->param_type_begin(),
                                            e = FT->param_type_end();
     i != e; ++i, ++ArgIndex) {
  const ParmVarDecl *PD = FD->getParamDecl(ArgIndex);
  SourceLocation ParamLoc = PD->getLocation();
  if (CheckLiteralType(SemaRef, Kind, ParamLoc, *i,
                       diag::err_constexpr_non_literal_param, ArgIndex + 1,
                       PD->getSourceRange(), isa<CXXConstructorDecl>(FD),
                       FD->isConsteval()))
    return false;
}
return true;
1698}

1700/// Check whether a function's return type is a literal type. If so, return
1701/// true. If not, produce a suitable diagnostic and return false.
1702static bool CheckConstexprReturnType(Sema &SemaRef, const FunctionDecl *FD,
                                   Sema::CheckConstexprKind Kind) {
if (CheckLiteralType(SemaRef, Kind, FD->getLocation(), FD->getReturnType(),
                     diag::err_constexpr_non_literal_return,
                     FD->isConsteval()))
  return false;
return true;
1709}

1711/// Get diagnostic %select index for tag kind for
1712/// record diagnostic message.
1713/// WARNING: Indexes apply to particular diagnostics only!
1714///
1715/// \returns diagnostic %select index.
1716static unsigned getRecordDiagFromTagKind(TagTypeKind Tag) {
switch (Tag) {
case TTK_Struct: return 0;
case TTK_Interface: return 1;
case TTK_Class:  return 2;
default: llvm_unreachable("Invalid tag kind for record diagnostic!")__builtin_unreachable();
}
1723}

1725static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
                                     Stmt *Body,
                                     Sema::CheckConstexprKind Kind);

1729// Check whether a function declaration satisfies the requirements of a
1730// constexpr function definition or a constexpr constructor definition. If so,
1731// return true. If not, produce appropriate diagnostics (unless asked not to by
1732// Kind) and return false.
1733//
1734// This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
1735bool Sema::CheckConstexprFunctionDefinition(const FunctionDecl *NewFD,
                                          CheckConstexprKind Kind) {
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
if (MD && MD->isInstance()) {
  // C++11 [dcl.constexpr]p4:
  //  The definition of a constexpr constructor shall satisfy the following
  //  constraints:
  //  - the class shall not have any virtual base classes;
  //
  // FIXME: This only applies to constructors and destructors, not arbitrary
  // member functions.
  const CXXRecordDecl *RD = MD->getParent();
  if (RD->getNumVBases()) {
    if (Kind == CheckConstexprKind::CheckValid)
      return false;

    Diag(NewFD->getLocation(), diag::err_constexpr_virtual_base)
      << isa<CXXConstructorDecl>(NewFD)
      << getRecordDiagFromTagKind(RD->getTagKind()) << RD->getNumVBases();
    for (const auto &I : RD->vbases())
      Diag(I.getBeginLoc(), diag::note_constexpr_virtual_base_here)
          << I.getSourceRange();
    return false;
  }
}

if (!isa<CXXConstructorDecl>(NewFD)) {
  // C++11 [dcl.constexpr]p3:
  //  The definition of a constexpr function shall satisfy the following
  //  constraints:
  // - it shall not be virtual; (removed in C++20)
  const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD);
  if (Method && Method->isVirtual()) {
    if (getLangOpts().CPlusPlus20) {
      if (Kind == CheckConstexprKind::Diagnose)
        Diag(Method->getLocation(), diag::warn_cxx17_compat_constexpr_virtual);
    } else {
      if (Kind == CheckConstexprKind::CheckValid)
        return false;

      Method = Method->getCanonicalDecl();
      Diag(Method->getLocation(), diag::err_constexpr_virtual);

      // If it's not obvious why this function is virtual, find an overridden
      // function which uses the 'virtual' keyword.
      const CXXMethodDecl *WrittenVirtual = Method;
      while (!WrittenVirtual->isVirtualAsWritten())
        WrittenVirtual = *WrittenVirtual->begin_overridden_methods();
      if (WrittenVirtual != Method)
        Diag(WrittenVirtual->getLocation(),
             diag::note_overridden_virtual_function);
      return false;
    }
  }

  // - its return type shall be a literal type;
  if (!CheckConstexprReturnType(*this, NewFD, Kind))
    return false;
}

if (auto *Dtor = dyn_cast<CXXDestructorDecl>(NewFD)) {
  // A destructor can be constexpr only if the defaulted destructor could be;
  // we don't need to check the members and bases if we already know they all
  // have constexpr destructors.
  if (!Dtor->getParent()->defaultedDestructorIsConstexpr()) {
    if (Kind == CheckConstexprKind::CheckValid)
      return false;
    if (!CheckConstexprDestructorSubobjects(*this, Dtor, Kind))
      return false;
  }
}

// - each of its parameter types shall be a literal type;
if (!CheckConstexprParameterTypes(*this, NewFD, Kind))
  return false;

Stmt *Body = NewFD->getBody();
assert(Body &&((void)0)
       "CheckConstexprFunctionDefinition called on function with no body")((void)0);
return CheckConstexprFunctionBody(*this, NewFD, Body, Kind);
1815}

1817/// Check the given declaration statement is legal within a constexpr function
1818/// body. C++11 [dcl.constexpr]p3,p4, and C++1y [dcl.constexpr]p3.
1819///
1820/// \return true if the body is OK (maybe only as an extension), false if we
1821///         have diagnosed a problem.
1822static bool CheckConstexprDeclStmt(Sema &SemaRef, const FunctionDecl *Dcl,
                                 DeclStmt *DS, SourceLocation &Cxx1yLoc,
                                 Sema::CheckConstexprKind Kind) {
// C++11 [dcl.constexpr]p3 and p4:
//  The definition of a constexpr function(p3) or constructor(p4) [...] shall
//  contain only
for (const auto *DclIt : DS->decls()) {
  switch (DclIt->getKind()) {
  case Decl::StaticAssert:
  case Decl::Using:
  case Decl::UsingShadow:
  case Decl::UsingDirective:
  case Decl::UnresolvedUsingTypename:
  case Decl::UnresolvedUsingValue:
  case Decl::UsingEnum:
    //   - static_assert-declarations
    //   - using-declarations,
    //   - using-directives,
    //   - using-enum-declaration
    continue;

  case Decl::Typedef:
  case Decl::TypeAlias: {
    //   - typedef declarations and alias-declarations that do not define
    //     classes or enumerations,
    const auto *TN = cast<TypedefNameDecl>(DclIt);
    if (TN->getUnderlyingType()->isVariablyModifiedType()) {
      // Don't allow variably-modified types in constexpr functions.
      if (Kind == Sema::CheckConstexprKind::Diagnose) {
        TypeLoc TL = TN->getTypeSourceInfo()->getTypeLoc();
        SemaRef.Diag(TL.getBeginLoc(), diag::err_constexpr_vla)
          << TL.getSourceRange() << TL.getType()
          << isa<CXXConstructorDecl>(Dcl);
      }
      return false;
    }
    continue;
  }

  case Decl::Enum:
  case Decl::CXXRecord:
    // C++1y allows types to be defined, not just declared.
    if (cast<TagDecl>(DclIt)->isThisDeclarationADefinition()) {
      if (Kind == Sema::CheckConstexprKind::Diagnose) {
        SemaRef.Diag(DS->getBeginLoc(),
                     SemaRef.getLangOpts().CPlusPlus14
                         ? diag::warn_cxx11_compat_constexpr_type_definition
                         : diag::ext_constexpr_type_definition)
            << isa<CXXConstructorDecl>(Dcl);
      } else if (!SemaRef.getLangOpts().CPlusPlus14) {
        return false;
      }
    }
    continue;

  case Decl::EnumConstant:
  case Decl::IndirectField:
  case Decl::ParmVar:
    // These can only appear with other declarations which are banned in
    // C++11 and permitted in C++1y, so ignore them.
    continue;

  case Decl::Var:
  case Decl::Decomposition: {
    // C++1y [dcl.constexpr]p3 allows anything except:
    //   a definition of a variable of non-literal type or of static or
    //   thread storage duration or [before C++2a] for which no
    //   initialization is performed.
    const auto *VD = cast<VarDecl>(DclIt);
    if (VD->isThisDeclarationADefinition()) {
      if (VD->isStaticLocal()) {
        if (Kind == Sema::CheckConstexprKind::Diagnose) {
          SemaRef.Diag(VD->getLocation(),
                       diag::err_constexpr_local_var_static)
            << isa<CXXConstructorDecl>(Dcl)
            << (VD->getTLSKind() == VarDecl::TLS_Dynamic);
        }
        return false;
      }
      if (CheckLiteralType(SemaRef, Kind, VD->getLocation(), VD->getType(),
                           diag::err_constexpr_local_var_non_literal_type,
                           isa<CXXConstructorDecl>(Dcl)))
        return false;
      if (!VD->getType()->isDependentType() &&
          !VD->hasInit() && !VD->isCXXForRangeDecl()) {
        if (Kind == Sema::CheckConstexprKind::Diagnose) {
          SemaRef.Diag(
              VD->getLocation(),
              SemaRef.getLangOpts().CPlusPlus20
                  ? diag::warn_cxx17_compat_constexpr_local_var_no_init
                  : diag::ext_constexpr_local_var_no_init)
              << isa<CXXConstructorDecl>(Dcl);
        } else if (!SemaRef.getLangOpts().CPlusPlus20) {
          return false;
        }
        continue;
      }
    }
    if (Kind == Sema::CheckConstexprKind::Diagnose) {
      SemaRef.Diag(VD->getLocation(),
                   SemaRef.getLangOpts().CPlusPlus14
                    ? diag::warn_cxx11_compat_constexpr_local_var
                    : diag::ext_constexpr_local_var)
        << isa<CXXConstructorDecl>(Dcl);
    } else if (!SemaRef.getLangOpts().CPlusPlus14) {
      return false;
    }
    continue;
  }

  case Decl::NamespaceAlias:
  case Decl::Function:
    // These are disallowed in C++11 and permitted in C++1y. Allow them
    // everywhere as an extension.
    if (!Cxx1yLoc.isValid())
      Cxx1yLoc = DS->getBeginLoc();
    continue;

  default:
    if (Kind == Sema::CheckConstexprKind::Diagnose) {
      SemaRef.Diag(DS->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
          << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
    }
    return false;
  }
}

return true;
1950}

1952/// Check that the given field is initialized within a constexpr constructor.
1953///
1954/// \param Dcl The constexpr constructor being checked.
1955/// \param Field The field being checked. This may be a member of an anonymous
1956///        struct or union nested within the class being checked.
1957/// \param Inits All declarations, including anonymous struct/union members and
1958///        indirect members, for which any initialization was provided.
1959/// \param Diagnosed Whether we've emitted the error message yet. Used to attach
1960///        multiple notes for different members to the same error.
1961/// \param Kind Whether we're diagnosing a constructor as written or determining
1962///        whether the formal requirements are satisfied.
1963/// \return \c false if we're checking for validity and the constructor does
1964///         not satisfy the requirements on a constexpr constructor.
1965static bool CheckConstexprCtorInitializer(Sema &SemaRef,
                                        const FunctionDecl *Dcl,
                                        FieldDecl *Field,
                                        llvm::SmallSet<Decl*, 16> &Inits,
                                        bool &Diagnosed,
                                        Sema::CheckConstexprKind Kind) {
// In C++20 onwards, there's nothing to check for validity.
if (Kind == Sema::CheckConstexprKind::CheckValid &&
    SemaRef.getLangOpts().CPlusPlus20)
  return true;

if (Field->isInvalidDecl())
  return true;

if (Field->isUnnamedBitfield())
  return true;

// Anonymous unions with no variant members and empty anonymous structs do not
// need to be explicitly initialized. FIXME: Anonymous structs that contain no
// indirect fields don't need initializing.
if (Field->isAnonymousStructOrUnion() &&
    (Field->getType()->isUnionType()
         ? !Field->getType()->getAsCXXRecordDecl()->hasVariantMembers()
         : Field->getType()->getAsCXXRecordDecl()->isEmpty()))
  return true;

if (!Inits.count(Field)) {
  if (Kind == Sema::CheckConstexprKind::Diagnose) {
    if (!Diagnosed) {
      SemaRef.Diag(Dcl->getLocation(),
                   SemaRef.getLangOpts().CPlusPlus20
                       ? diag::warn_cxx17_compat_constexpr_ctor_missing_init
                       : diag::ext_constexpr_ctor_missing_init);
      Diagnosed = true;
    }
    SemaRef.Diag(Field->getLocation(),
                 diag::note_constexpr_ctor_missing_init);
  } else if (!SemaRef.getLangOpts().CPlusPlus20) {
    return false;
  }
} else if (Field->isAnonymousStructOrUnion()) {
  const RecordDecl *RD = Field->getType()->castAs<RecordType>()->getDecl();
  for (auto *I : RD->fields())
    // If an anonymous union contains an anonymous struct of which any member
    // is initialized, all members must be initialized.
    if (!RD->isUnion() || Inits.count(I))
      if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
                                         Kind))
        return false;
}
return true;
2016}

2018/// Check the provided statement is allowed in a constexpr function
2019/// definition.
2020static bool
2021CheckConstexprFunctionStmt(Sema &SemaRef, const FunctionDecl *Dcl, Stmt *S,
                         SmallVectorImpl<SourceLocation> &ReturnStmts,
                         SourceLocation &Cxx1yLoc, SourceLocation &Cxx2aLoc,
                         Sema::CheckConstexprKind Kind) {
// - its function-body shall be [...] a compound-statement that contains only
switch (S->getStmtClass()) {
case Stmt::NullStmtClass:
  //   - null statements,
  return true;

case Stmt::DeclStmtClass:
  //   - static_assert-declarations
  //   - using-declarations,
  //   - using-directives,
  //   - typedef declarations and alias-declarations that do not define
  //     classes or enumerations,
  if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc, Kind))
    return false;
  return true;

case Stmt::ReturnStmtClass:
  //   - and exactly one return statement;
  if (isa<CXXConstructorDecl>(Dcl)) {
    // C++1y allows return statements in constexpr constructors.
    if (!Cxx1yLoc.isValid())
      Cxx1yLoc = S->getBeginLoc();
    return true;
  }

  ReturnStmts.push_back(S->getBeginLoc());
  return true;

case Stmt::CompoundStmtClass: {
  // C++1y allows compound-statements.
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();

  CompoundStmt *CompStmt = cast<CompoundStmt>(S);
  for (auto *BodyIt : CompStmt->body()) {
    if (!CheckConstexprFunctionStmt(SemaRef, Dcl, BodyIt, ReturnStmts,
                                    Cxx1yLoc, Cxx2aLoc, Kind))
      return false;
  }
  return true;
}

case Stmt::AttributedStmtClass:
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();
  return true;

case Stmt::IfStmtClass: {
  // C++1y allows if-statements.
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();

  IfStmt *If = cast<IfStmt>(S);
  if (!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getThen(), ReturnStmts,
                                  Cxx1yLoc, Cxx2aLoc, Kind))
    return false;
  if (If->getElse() &&
      !CheckConstexprFunctionStmt(SemaRef, Dcl, If->getElse(), ReturnStmts,
                                  Cxx1yLoc, Cxx2aLoc, Kind))
    return false;
  return true;
}

case Stmt::WhileStmtClass:
case Stmt::DoStmtClass:
case Stmt::ForStmtClass:
case Stmt::CXXForRangeStmtClass:
case Stmt::ContinueStmtClass:
  // C++1y allows all of these. We don't allow them as extensions in C++11,
  // because they don't make sense without variable mutation.
  if (!SemaRef.getLangOpts().CPlusPlus14)
    break;
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();
  for (Stmt *SubStmt : S->children())
    if (SubStmt &&
        !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
                                    Cxx1yLoc, Cxx2aLoc, Kind))
      return false;
  return true;

case Stmt::SwitchStmtClass:
case Stmt::CaseStmtClass:
case Stmt::DefaultStmtClass:
case Stmt::BreakStmtClass:
  // C++1y allows switch-statements, and since they don't need variable
  // mutation, we can reasonably allow them in C++11 as an extension.
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();
  for (Stmt *SubStmt : S->children())
    if (SubStmt &&
        !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
                                    Cxx1yLoc, Cxx2aLoc, Kind))
      return false;
  return true;

case Stmt::GCCAsmStmtClass:
case Stmt::MSAsmStmtClass:
  // C++2a allows inline assembly statements.
case Stmt::CXXTryStmtClass:
  if (Cxx2aLoc.isInvalid())
    Cxx2aLoc = S->getBeginLoc();
  for (Stmt *SubStmt : S->children()) {
    if (SubStmt &&
        !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
                                    Cxx1yLoc, Cxx2aLoc, Kind))
      return false;
  }
  return true;

case Stmt::CXXCatchStmtClass:
  // Do not bother checking the language mode (already covered by the
  // try block check).
  if (!CheckConstexprFunctionStmt(SemaRef, Dcl,
                                  cast<CXXCatchStmt>(S)->getHandlerBlock(),
                                  ReturnStmts, Cxx1yLoc, Cxx2aLoc, Kind))
    return false;
  return true;

default:
  if (!isa<Expr>(S))
    break;

  // C++1y allows expression-statements.
  if (!Cxx1yLoc.isValid())
    Cxx1yLoc = S->getBeginLoc();
  return true;
}

if (Kind == Sema::CheckConstexprKind::Diagnose) {
  SemaRef.Diag(S->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
      << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
}
return false;
2159}

2161/// Check the body for the given constexpr function declaration only contains
2162/// the permitted types of statement. C++11 [dcl.constexpr]p3,p4.
2163///
2164/// \return true if the body is OK, false if we have found or diagnosed a
2165/// problem.
2166static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
                                     Stmt *Body,
                                     Sema::CheckConstexprKind Kind) {
SmallVector<SourceLocation, 4> ReturnStmts;

if (isa<CXXTryStmt>(Body)) {
  // C++11 [dcl.constexpr]p3:
  //  The definition of a constexpr function shall satisfy the following
  //  constraints: [...]
  // - its function-body shall be = delete, = default, or a
  //   compound-statement
  //
  // C++11 [dcl.constexpr]p4:
  //  In the definition of a constexpr constructor, [...]
  // - its function-body shall not be a function-try-block;
  //
  // This restriction is lifted in C++2a, as long as inner statements also
  // apply the general constexpr rules.
  switch (Kind) {
  case Sema::CheckConstexprKind::CheckValid:
    if (!SemaRef.getLangOpts().CPlusPlus20)
      return false;
    break;

  case Sema::CheckConstexprKind::Diagnose:
    SemaRef.Diag(Body->getBeginLoc(),
         !SemaRef.getLangOpts().CPlusPlus20
             ? diag::ext_constexpr_function_try_block_cxx20
             : diag::warn_cxx17_compat_constexpr_function_try_block)
        << isa<CXXConstructorDecl>(Dcl);
    break;
  }
}

// - its function-body shall be [...] a compound-statement that contains only
//   [... list of cases ...]
//
// Note that walking the children here is enough to properly check for
// CompoundStmt and CXXTryStmt body.
SourceLocation Cxx1yLoc, Cxx2aLoc;
for (Stmt *SubStmt : Body->children()) {
  if (SubStmt &&
      !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
                                  Cxx1yLoc, Cxx2aLoc, Kind))
    return false;
}

if (Kind == Sema::CheckConstexprKind::CheckValid) {
  // If this is only valid as an extension, report that we don't satisfy the
  // constraints of the current language.
  if ((Cxx2aLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus20) ||
      (Cxx1yLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus17))
    return false;
} else if (Cxx2aLoc.isValid()) {
  SemaRef.Diag(Cxx2aLoc,
       SemaRef.getLangOpts().CPlusPlus20
         ? diag::warn_cxx17_compat_constexpr_body_invalid_stmt
         : diag::ext_constexpr_body_invalid_stmt_cxx20)
    << isa<CXXConstructorDecl>(Dcl);
} else if (Cxx1yLoc.isValid()) {
  SemaRef.Diag(Cxx1yLoc,
       SemaRef.getLangOpts().CPlusPlus14
         ? diag::warn_cxx11_compat_constexpr_body_invalid_stmt
         : diag::ext_constexpr_body_invalid_stmt)
    << isa<CXXConstructorDecl>(Dcl);
}

if (const CXXConstructorDecl *Constructor
      = dyn_cast<CXXConstructorDecl>(Dcl)) {
  const CXXRecordDecl *RD = Constructor->getParent();
  // DR1359:
  // - every non-variant non-static data member and base class sub-object
  //   shall be initialized;
  // DR1460:
  // - if the class is a union having variant members, exactly one of them
  //   shall be initialized;
  if (RD->isUnion()) {
    if (Constructor->getNumCtorInitializers() == 0 &&
        RD->hasVariantMembers()) {
      if (Kind == Sema::CheckConstexprKind::Diagnose) {
        SemaRef.Diag(
            Dcl->getLocation(),
            SemaRef.getLangOpts().CPlusPlus20
                ? diag::warn_cxx17_compat_constexpr_union_ctor_no_init
                : diag::ext_constexpr_union_ctor_no_init);
      } else if (!SemaRef.getLangOpts().CPlusPlus20) {
        return false;
      }
    }
  } else if (!Constructor->isDependentContext() &&
             !Constructor->isDelegatingConstructor()) {
    assert(RD->getNumVBases() == 0 && "constexpr ctor with virtual bases")((void)0);

    // Skip detailed checking if we have enough initializers, and we would
    // allow at most one initializer per member.
    bool AnyAnonStructUnionMembers = false;
    unsigned Fields = 0;
    for (CXXRecordDecl::field_iterator I = RD->field_begin(),
         E = RD->field_end(); I != E; ++I, ++Fields) {
      if (I->isAnonymousStructOrUnion()) {
        AnyAnonStructUnionMembers = true;
        break;
      }
    }
    // DR1460:
    // - if the class is a union-like class, but is not a union, for each of
    //   its anonymous union members having variant members, exactly one of
    //   them shall be initialized;
    if (AnyAnonStructUnionMembers ||
        Constructor->getNumCtorInitializers() != RD->getNumBases() + Fields) {
      // Check initialization of non-static data members. Base classes are
      // always initialized so do not need to be checked. Dependent bases
      // might not have initializers in the member initializer list.
      llvm::SmallSet<Decl*, 16> Inits;
      for (const auto *I: Constructor->inits()) {
        if (FieldDecl *FD = I->getMember())
          Inits.insert(FD);
        else if (IndirectFieldDecl *ID = I->getIndirectMember())
          Inits.insert(ID->chain_begin(), ID->chain_end());
      }

      bool Diagnosed = false;
      for (auto *I : RD->fields())
        if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
                                           Kind))
          return false;
    }
  }
} else {
  if (ReturnStmts.empty()) {
    // C++1y doesn't require constexpr functions to contain a 'return'
    // statement. We still do, unless the return type might be void, because
    // otherwise if there's no return statement, the function cannot
    // be used in a core constant expression.
    bool OK = SemaRef.getLangOpts().CPlusPlus14 &&
              (Dcl->getReturnType()->isVoidType() ||
               Dcl->getReturnType()->isDependentType());
    switch (Kind) {
    case Sema::CheckConstexprKind::Diagnose:
      SemaRef.Diag(Dcl->getLocation(),
                   OK ? diag::warn_cxx11_compat_constexpr_body_no_return
                      : diag::err_constexpr_body_no_return)
          << Dcl->isConsteval();
      if (!OK)
        return false;
      break;

    case Sema::CheckConstexprKind::CheckValid:
      // The formal requirements don't include this rule in C++14, even
      // though the "must be able to produce a constant expression" rules
      // still imply it in some cases.
      if (!SemaRef.getLangOpts().CPlusPlus14)
        return false;
      break;
    }
  } else if (ReturnStmts.size() > 1) {
    switch (Kind) {
    case Sema::CheckConstexprKind::Diagnose:
      SemaRef.Diag(
          ReturnStmts.back(),
          SemaRef.getLangOpts().CPlusPlus14
              ? diag::warn_cxx11_compat_constexpr_body_multiple_return
              : diag::ext_constexpr_body_multiple_return);
      for (unsigned I = 0; I < ReturnStmts.size() - 1; ++I)
        SemaRef.Diag(ReturnStmts[I],
                     diag::note_constexpr_body_previous_return);
      break;

    case Sema::CheckConstexprKind::CheckValid:
      if (!SemaRef.getLangOpts().CPlusPlus14)
        return false;
      break;
    }
  }
}

// C++11 [dcl.constexpr]p5:
//   if no function argument values exist such that the function invocation
//   substitution would produce a constant expression, the program is
//   ill-formed; no diagnostic required.
// C++11 [dcl.constexpr]p3:
//   - every constructor call and implicit conversion used in initializing the
//     return value shall be one of those allowed in a constant expression.
// C++11 [dcl.constexpr]p4:
//   - every constructor involved in initializing non-static data members and
//     base class sub-objects shall be a constexpr constructor.
//
// Note that this rule is distinct from the "requirements for a constexpr
// function", so is not checked in CheckValid mode.
SmallVector<PartialDiagnosticAt, 8> Diags;
if (Kind == Sema::CheckConstexprKind::Diagnose &&
    !Expr::isPotentialConstantExpr(Dcl, Diags)) {
  SemaRef.Diag(Dcl->getLocation(),
               diag::ext_constexpr_function_never_constant_expr)
      << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
  for (size_t I = 0, N = Diags.size(); I != N; ++I)
    SemaRef.Diag(Diags[I].first, Diags[I].second);
  // Don't return false here: we allow this for compatibility in
  // system headers.
}

return true;
2368}

2370/// Get the class that is directly named by the current context. This is the
2371/// class for which an unqualified-id in this scope could name a constructor
2372/// or destructor.
2373///
2374/// If the scope specifier denotes a class, this will be that class.
2375/// If the scope specifier is empty, this will be the class whose
2376/// member-specification we are currently within. Otherwise, there
2377/// is no such class.
2378CXXRecordDecl *Sema::getCurrentClass(Scope *, const CXXScopeSpec *SS) {
assert(getLangOpts().CPlusPlus && "No class names in C!")((void)0);

if (SS && SS->isInvalid())
  return nullptr;

if (SS && SS->isNotEmpty()) {
  DeclContext *DC = computeDeclContext(*SS, true);
  return dyn_cast_or_null<CXXRecordDecl>(DC);
}

return dyn_cast_or_null<CXXRecordDecl>(CurContext);
2390}

2392/// isCurrentClassName - Determine whether the identifier II is the
2393/// name of the class type currently being defined. In the case of
2394/// nested classes, this will only return true if II is the name of
2395/// the innermost class.
2396bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *S,
                            const CXXScopeSpec *SS) {
CXXRecordDecl *CurDecl = getCurrentClass(S, SS);
return CurDecl && &II == CurDecl->getIdentifier();
2400}

2402/// Determine whether the identifier II is a typo for the name of
2403/// the class type currently being defined. If so, update it to the identifier
2404/// that should have been used.
2405bool Sema::isCurrentClassNameTypo(IdentifierInfo *&II, const CXXScopeSpec *SS) {
assert(getLangOpts().CPlusPlus && "No class names in C!")((void)0);

if (!getLangOpts().SpellChecking)
  return false;

CXXRecordDecl *CurDecl;
if (SS && SS->isSet() && !SS->isInvalid()) {
  DeclContext *DC = computeDeclContext(*SS, true);
  CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
} else
  CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);

if (CurDecl && CurDecl->getIdentifier() && II != CurDecl->getIdentifier() &&
    3 * II->getName().edit_distance(CurDecl->getIdentifier()->getName())
        < II->getLength()) {
  II = CurDecl->getIdentifier();
  return true;
}

return false;
2426}

2428/// Determine whether the given class is a base class of the given
2429/// class, including looking at dependent bases.
2430static bool findCircularInheritance(const CXXRecordDecl *Class,
                                  const CXXRecordDecl *Current) {
SmallVector<const CXXRecordDecl*, 8> Queue;

Class = Class->getCanonicalDecl();
while (true) {
  for (const auto &I : Current->bases()) {
    CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
    if (!Base)
      continue;

    Base = Base->getDefinition();
    if (!Base)
      continue;

    if (Base->getCanonicalDecl() == Class)
      return true;

    Queue.push_back(Base);
  }

  if (Queue.empty())
    return false;

  Current = Queue.pop_back_val();
}

return false;
2458}

2460/// Check the validity of a C++ base class specifier.
2461///
2462/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
2463/// and returns NULL otherwise.
2464CXXBaseSpecifier *
2465Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
                       SourceRange SpecifierRange,
                       bool Virtual, AccessSpecifier Access,
                       TypeSourceInfo *TInfo,
                       SourceLocation EllipsisLoc) {
QualType BaseType = TInfo->getType();
if (BaseType->containsErrors()) {
  // Already emitted a diagnostic when parsing the error type.
  return nullptr;
}
// C++ [class.union]p1:
//   A union shall not have base classes.
if (Class->isUnion()) {
  Diag(Class->getLocation(), diag::err_base_clause_on_union)
    << SpecifierRange;
  return nullptr;
}

if (EllipsisLoc.isValid() &&
    !TInfo->getType()->containsUnexpandedParameterPack()) {
  Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
    << TInfo->getTypeLoc().getSourceRange();
  EllipsisLoc = SourceLocation();
}

SourceLocation BaseLoc = TInfo->getTypeLoc().getBeginLoc();

if (BaseType->isDependentType()) {
  // Make sure that we don't have circular inheritance among our dependent
  // bases. For non-dependent bases, the check for completeness below handles
  // this.
  if (CXXRecordDecl *BaseDecl = BaseType->getAsCXXRecordDecl()) {
    if (BaseDecl->getCanonicalDecl() == Class->getCanonicalDecl() ||
        ((BaseDecl = BaseDecl->getDefinition()) &&
         findCircularInheritance(Class, BaseDecl))) {
      Diag(BaseLoc, diag::err_circular_inheritance)
        << BaseType << Context.getTypeDeclType(Class);

      if (BaseDecl->getCanonicalDecl() != Class->getCanonicalDecl())
        Diag(BaseDecl->getLocation(), diag::note_previous_decl)
          << BaseType;

      return nullptr;
    }
  }

  // Make sure that we don't make an ill-formed AST where the type of the
  // Class is non-dependent and its attached base class specifier is an
  // dependent type, which violates invariants in many clang code paths (e.g.
  // constexpr evaluator). If this case happens (in errory-recovery mode), we
  // explicitly mark the Class decl invalid. The diagnostic was already
  // emitted.
  if (!Class->getTypeForDecl()->isDependentType())
    Class->setInvalidDecl();
  return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
                                        Class->getTagKind() == TTK_Class,
                                        Access, TInfo, EllipsisLoc);
}

// Base specifiers must be record types.
if (!BaseType->isRecordType()) {
  Diag(BaseLoc, diag::err_base_must_be_class) << SpecifierRange;
  return nullptr;
}

// C++ [class.union]p1:
//   A union shall not be used as a base class.
if (BaseType->isUnionType()) {
  Diag(BaseLoc, diag::err_union_as_base_class) << SpecifierRange;
  return nullptr;
}

// For the MS ABI, propagate DLL attributes to base class templates.
if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
  if (Attr *ClassAttr = getDLLAttr(Class)) {
    if (auto *BaseTemplate = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
            BaseType->getAsCXXRecordDecl())) {
      propagateDLLAttrToBaseClassTemplate(Class, ClassAttr, BaseTemplate,
                                          BaseLoc);
    }
  }
}

// C++ [class.derived]p2:
//   The class-name in a base-specifier shall not be an incompletely
//   defined class.
if (RequireCompleteType(BaseLoc, BaseType,
                        diag::err_incomplete_base_class, SpecifierRange)) {
  Class->setInvalidDecl();
  return nullptr;
}

// If the base class is polymorphic or isn't empty, the new one is/isn't, too.
RecordDecl *BaseDecl = BaseType->castAs<RecordType>()->getDecl();
assert(BaseDecl && "Record type has no declaration")((void)0);
BaseDecl = BaseDecl->getDefinition();
assert(BaseDecl && "Base type is not incomplete, but has no definition")((void)0);
CXXRecordDecl *CXXBaseDecl = cast<CXXRecordDecl>(BaseDecl);
assert(CXXBaseDecl && "Base type is not a C++ type")((void)0);

// Microsoft docs say:
// "If a base-class has a code_seg attribute, derived classes must have the
// same attribute."
const auto *BaseCSA = CXXBaseDecl->getAttr<CodeSegAttr>();
const auto *DerivedCSA = Class->getAttr<CodeSegAttr>();
if ((DerivedCSA || BaseCSA) &&
    (!BaseCSA || !DerivedCSA || BaseCSA->getName() != DerivedCSA->getName())) {
  Diag(Class->getLocation(), diag::err_mismatched_code_seg_base);
  Diag(CXXBaseDecl->getLocation(), diag::note_base_class_specified_here)
    << CXXBaseDecl;
  return nullptr;
}

// A class which contains a flexible array member is not suitable for use as a
// base class:
//   - If the layout determines that a base comes before another base,
//     the flexible array member would index into the subsequent base.
//   - If the layout determines that base comes before the derived class,
//     the flexible array member would index into the derived class.
if (CXXBaseDecl->hasFlexibleArrayMember()) {
  Diag(BaseLoc, diag::err_base_class_has_flexible_array_member)
    << CXXBaseDecl->getDeclName();
  return nullptr;
}

// C++ [class]p3:
//   If a class is marked final and it appears as a base-type-specifier in
//   base-clause, the program is ill-formed.
if (FinalAttr *FA = CXXBaseDecl->getAttr<FinalAttr>()) {
  Diag(BaseLoc, diag::err_class_marked_final_used_as_base)
    << CXXBaseDecl->getDeclName()
    << FA->isSpelledAsSealed();
  Diag(CXXBaseDecl->getLocation(), diag::note_entity_declared_at)
      << CXXBaseDecl->getDeclName() << FA->getRange();
  return nullptr;
}

if (BaseDecl->isInvalidDecl())
  Class->setInvalidDecl();

// Create the base specifier.
return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
                                      Class->getTagKind() == TTK_Class,
                                      Access, TInfo, EllipsisLoc);
2609}

2611/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
2612/// one entry in the base class list of a class specifier, for
2613/// example:
2614///    class foo : public bar, virtual private baz {
2615/// 'public bar' and 'virtual private baz' are each base-specifiers.
2616BaseResult
2617Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
                       ParsedAttributes &Attributes,
                       bool Virtual, AccessSpecifier Access,
                       ParsedType basetype, SourceLocation BaseLoc,
                       SourceLocation EllipsisLoc) {
if (!classdecl)
  return true;

AdjustDeclIfTemplate(classdecl);
CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(classdecl);
if (!Class)
  return true;

// We haven't yet attached the base specifiers.
Class->setIsParsingBaseSpecifiers();

// We do not support any C++11 attributes on base-specifiers yet.
// Diagnose any attributes we see.
for (const ParsedAttr &AL : Attributes) {
  if (AL.isInvalid() || AL.getKind() == ParsedAttr::IgnoredAttribute)
    continue;
  Diag(AL.getLoc(), AL.getKind() == ParsedAttr::UnknownAttribute
                        ? (unsigned)diag::warn_unknown_attribute_ignored
                        : (unsigned)diag::err_base_specifier_attribute)
      << AL << AL.getRange();
}

TypeSourceInfo *TInfo = nullptr;
GetTypeFromParser(basetype, &TInfo);

if (EllipsisLoc.isInvalid() &&
    DiagnoseUnexpandedParameterPack(SpecifierRange.getBegin(), TInfo,
                                    UPPC_BaseType))
  return true;

if (CXXBaseSpecifier *BaseSpec = CheckBaseSpecifier(Class, SpecifierRange,
                                                    Virtual, Access, TInfo,
                                                    EllipsisLoc))
  return BaseSpec;
else
  Class->setInvalidDecl();

return true;
2660}

2662/// Use small set to collect indirect bases.  As this is only used
2663/// locally, there's no need to abstract the small size parameter.
2664typedef llvm::SmallPtrSet<QualType, 4> IndirectBaseSet;

2666/// Recursively add the bases of Type.  Don't add Type itself.
2667static void
2668NoteIndirectBases(ASTContext &Context, IndirectBaseSet &Set,
                const QualType &Type)
2670{
// Even though the incoming type is a base, it might not be
// a class -- it could be a template parm, for instance.
if (auto Rec = Type->getAs<RecordType>()) {
  auto Decl = Rec->getAsCXXRecordDecl();

  // Iterate over its bases.
  for (const auto &BaseSpec : Decl->bases()) {
    QualType Base = Context.getCanonicalType(BaseSpec.getType())
      .getUnqualifiedType();
    if (Set.insert(Base).second)
      // If we've not already seen it, recurse.
      NoteIndirectBases(Context, Set, Base);
  }
}
2685}

2687/// Performs the actual work of attaching the given base class
2688/// specifiers to a C++ class.
2689bool Sema::AttachBaseSpecifiers(CXXRecordDecl *Class,
                              MutableArrayRef<CXXBaseSpecifier *> Bases) {
if (Bases.empty())
  return false;

// Used to keep track of which base types we have already seen, so
// that we can properly diagnose redundant direct base types. Note
// that the key is always the unqualified canonical type of the base
// class.
std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes;

// Used to track indirect bases so we can see if a direct base is
// ambiguous.
IndirectBaseSet IndirectBaseTypes;

// Copy non-redundant base specifiers into permanent storage.
unsigned NumGoodBases = 0;
bool Invalid = false;
for (unsigned idx = 0; idx < Bases.size(); ++idx) {
  QualType NewBaseType
    = Context.getCanonicalType(Bases[idx]->getType());
  NewBaseType = NewBaseType.getLocalUnqualifiedType();

  CXXBaseSpecifier *&KnownBase = KnownBaseTypes[NewBaseType];
  if (KnownBase) {
    // C++ [class.mi]p3:
    //   A class shall not be specified as a direct base class of a
    //   derived class more than once.
    Diag(Bases[idx]->getBeginLoc(), diag::err_duplicate_base_class)
        << KnownBase->getType() << Bases[idx]->getSourceRange();

    // Delete the duplicate base class specifier; we're going to
    // overwrite its pointer later.
    Context.Deallocate(Bases[idx]);

    Invalid = true;
  } else {
    // Okay, add this new base class.
    KnownBase = Bases[idx];
    Bases[NumGoodBases++] = Bases[idx];

    // Note this base's direct & indirect bases, if there could be ambiguity.
    if (Bases.size() > 1)
      NoteIndirectBases(Context, IndirectBaseTypes, NewBaseType);

    if (const RecordType *Record = NewBaseType->getAs<RecordType>()) {
      const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
      if (Class->isInterface() &&
            (!RD->isInterfaceLike() ||
             KnownBase->getAccessSpecifier() != AS_public)) {
        // The Microsoft extension __interface does not permit bases that
        // are not themselves public interfaces.
        Diag(KnownBase->getBeginLoc(), diag::err_invalid_base_in_interface)
            << getRecordDiagFromTagKind(RD->getTagKind()) << RD
            << RD->getSourceRange();
        Invalid = true;
      }
      if (RD->hasAttr<WeakAttr>())
        Class->addAttr(WeakAttr::CreateImplicit(Context));
    }
  }
}

// Attach the remaining base class specifiers to the derived class.
Class->setBases(Bases.data(), NumGoodBases);

// Check that the only base classes that are duplicate are virtual.
for (unsigned idx = 0; idx < NumGoodBases; ++idx) {
  // Check whether this direct base is inaccessible due to ambiguity.
  QualType BaseType = Bases[idx]->getType();

  // Skip all dependent types in templates being used as base specifiers.
  // Checks below assume that the base specifier is a CXXRecord.
  if (BaseType->isDependentType())
    continue;

  CanQualType CanonicalBase = Context.getCanonicalType(BaseType)
    .getUnqualifiedType();

  if (IndirectBaseTypes.count(CanonicalBase)) {
    CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                       /*DetectVirtual=*/true);
    bool found
      = Class->isDerivedFrom(CanonicalBase->getAsCXXRecordDecl(), Paths);
    assert(found)((void)0);
    (void)found;

    if (Paths.isAmbiguous(CanonicalBase))
      Diag(Bases[idx]->getBeginLoc(), diag::warn_inaccessible_base_class)
          << BaseType << getAmbiguousPathsDisplayString(Paths)
          << Bases[idx]->getSourceRange();
    else
      assert(Bases[idx]->isVirtual())((void)0);
  }

  // Delete the base class specifier, since its data has been copied
  // into the CXXRecordDecl.
  Context.Deallocate(Bases[idx]);
}

return Invalid;
2790}

2792/// ActOnBaseSpecifiers - Attach the given base specifiers to the
2793/// class, after checking whether there are any duplicate base
2794/// classes.
2795void Sema::ActOnBaseSpecifiers(Decl *ClassDecl,
                             MutableArrayRef<CXXBaseSpecifier *> Bases) {
if (!ClassDecl || Bases.empty())
  return;

AdjustDeclIfTemplate(ClassDecl);
AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), Bases);
2802}

2804/// Determine whether the type \p Derived is a C++ class that is
2805/// derived from the type \p Base.
2806bool Sema::IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base) {
if (!getLangOpts().CPlusPlus)
  return false;

CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
if (!DerivedRD)
  return false;

CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
if (!BaseRD)
  return false;

// If either the base or the derived type is invalid, don't try to
// check whether one is derived from the other.
if (BaseRD->isInvalidDecl() || DerivedRD->isInvalidDecl())
  return false;

// FIXME: In a modules build, do we need the entire path to be visible for us
// to be able to use the inheritance relationship?
if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
  return false;

return DerivedRD->isDerivedFrom(BaseRD);
2829}

2831/// Determine whether the type \p Derived is a C++ class that is
2832/// derived from the type \p Base.
2833bool Sema::IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
                       CXXBasePaths &Paths) {
if (!getLangOpts().CPlusPlus)
  return false;

CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
if (!DerivedRD)
  return false;

CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
if (!BaseRD)
  return false;

if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
  return false;

return DerivedRD->isDerivedFrom(BaseRD, Paths);
2850}

2852static void BuildBasePathArray(const CXXBasePath &Path,
                             CXXCastPath &BasePathArray) {
// We first go backward and check if we have a virtual base.
// FIXME: It would be better if CXXBasePath had the base specifier for
// the nearest virtual base.
unsigned Start = 0;
for (unsigned I = Path.size(); I != 0; --I) {
  if (Path[I - 1].Base->isVirtual()) {
    Start = I - 1;
    break;
  }
}

// Now add all bases.
for (unsigned I = Start, E = Path.size(); I != E; ++I)
  BasePathArray.push_back(const_cast<CXXBaseSpecifier*>(Path[I].Base));
2868}


2871void Sema::BuildBasePathArray(const CXXBasePaths &Paths,
                            CXXCastPath &BasePathArray) {
assert(BasePathArray.empty() && "Base path array must be empty!")((void)0);
assert(Paths.isRecordingPaths() && "Must record paths!")((void)0);
return ::BuildBasePathArray(Paths.front(), BasePathArray);
2876}
2877/// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
2878/// conversion (where Derived and Base are class types) is
2879/// well-formed, meaning that the conversion is unambiguous (and
2880/// that all of the base classes are accessible). Returns true
2881/// and emits a diagnostic if the code is ill-formed, returns false
2882/// otherwise. Loc is the location where this routine should point to
2883/// if there is an error, and Range is the source range to highlight
2884/// if there is an error.
2885///
2886/// If either InaccessibleBaseID or AmbiguousBaseConvID are 0, then the
2887/// diagnostic for the respective type of error will be suppressed, but the
2888/// check for ill-formed code will still be performed.
2889bool
2890Sema::CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                 unsigned InaccessibleBaseID,
                                 unsigned AmbiguousBaseConvID,
                                 SourceLocation Loc, SourceRange Range,
                                 DeclarationName Name,
                                 CXXCastPath *BasePath,
                                 bool IgnoreAccess) {
// First, determine whether the path from Derived to Base is
// ambiguous. This is slightly more expensive than checking whether
// the Derived to Base conversion exists, because here we need to
// explore multiple paths to determine if there is an ambiguity.
CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                   /*DetectVirtual=*/false);
bool DerivationOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
if (!DerivationOkay)
  return true;

const CXXBasePath *Path = nullptr;
if (!Paths.isAmbiguous(Context.getCanonicalType(Base).getUnqualifiedType()))
  Path = &Paths.front();

// For MSVC compatibility, check if Derived directly inherits from Base. Clang
// warns about this hierarchy under -Winaccessible-base, but MSVC allows the
// user to access such bases.
if (!Path && getLangOpts().MSVCCompat) {
  for (const CXXBasePath &PossiblePath : Paths) {
    if (PossiblePath.size() == 1) {
      Path = &PossiblePath;
      if (AmbiguousBaseConvID)
        Diag(Loc, diag::ext_ms_ambiguous_direct_base)
            << Base << Derived << Range;
      break;
    }
  }
}

if (Path) {
  if (!IgnoreAccess) {
    // Check that the base class can be accessed.
    switch (
        CheckBaseClassAccess(Loc, Base, Derived, *Path, InaccessibleBaseID)) {
    case AR_inaccessible:
      return true;
    case AR_accessible:
    case AR_dependent:
    case AR_delayed:
      break;
    }
  }

  // Build a base path if necessary.
  if (BasePath)
    ::BuildBasePathArray(*Path, *BasePath);
  return false;
}

if (AmbiguousBaseConvID) {
  // We know that the derived-to-base conversion is ambiguous, and
  // we're going to produce a diagnostic. Perform the derived-to-base
  // search just one more time to compute all of the possible paths so
  // that we can print them out. This is more expensive than any of
  // the previous derived-to-base checks we've done, but at this point
  // performance isn't as much of an issue.
  Paths.clear();
  Paths.setRecordingPaths(true);
  bool StillOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
  assert(StillOkay && "Can only be used with a derived-to-base conversion")((void)0);
  (void)StillOkay;

  // Build up a textual representation of the ambiguous paths, e.g.,
  // D -> B -> A, that will be used to illustrate the ambiguous
  // conversions in the diagnostic. We only print one of the paths
  // to each base class subobject.
  std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);

  Diag(Loc, AmbiguousBaseConvID)
  << Derived << Base << PathDisplayStr << Range << Name;
}
return true;
2969}

2971bool
2972Sema::CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                 SourceLocation Loc, SourceRange Range,
                                 CXXCastPath *BasePath,
                                 bool IgnoreAccess) {
return CheckDerivedToBaseConversion(
    Derived, Base, diag::err_upcast_to_inaccessible_base,
    diag::err_ambiguous_derived_to_base_conv, Loc, Range, DeclarationName(),
    BasePath, IgnoreAccess);
2980}


2983/// Builds a string representing ambiguous paths from a
2984/// specific derived class to different subobjects of the same base
2985/// class.
2986///
2987/// This function builds a string that can be used in error messages
2988/// to show the different paths that one can take through the
2989/// inheritance hierarchy to go from the derived class to different
2990/// subobjects of a base class. The result looks something like this:
2991/// @code
2992/// struct D -> struct B -> struct A
2993/// struct D -> struct C -> struct A
2994/// @endcode
2995std::string Sema::getAmbiguousPathsDisplayString(CXXBasePaths &Paths) {
std::string PathDisplayStr;
std::set<unsigned> DisplayedPaths;
for (CXXBasePaths::paths_iterator Path = Paths.begin();
     Path != Paths.end(); ++Path) {
  if (DisplayedPaths.insert(Path->back().SubobjectNumber).second) {
    // We haven't displayed a path to this particular base
    // class subobject yet.
    PathDisplayStr += "\n    ";
    PathDisplayStr += Context.getTypeDeclType(Paths.getOrigin()).getAsString();
    for (CXXBasePath::const_iterator Element = Path->begin();
         Element != Path->end(); ++Element)
      PathDisplayStr += " -> " + Element->Base->getType().getAsString();
  }
}

return PathDisplayStr;
3012}

3014//===----------------------------------------------------------------------===//
3015// C++ class member Handling
3016//===----------------------------------------------------------------------===//

3018/// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
3019bool Sema::ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
                              SourceLocation ColonLoc,
                              const ParsedAttributesView &Attrs) {
assert(Access != AS_none && "Invalid kind for syntactic access specifier!")((void)0);
AccessSpecDecl *ASDecl = AccessSpecDecl::Create(Context, Access, CurContext,
                                                ASLoc, ColonLoc);
CurContext->addHiddenDecl(ASDecl);
return ProcessAccessDeclAttributeList(ASDecl, Attrs);
3027}

3029/// CheckOverrideControl - Check C++11 override control semantics.
3030void Sema::CheckOverrideControl(NamedDecl *D) {
if (D->isInvalidDecl())
  return;

// We only care about "override" and "final" declarations.
if (!D->hasAttr<OverrideAttr>() && !D->hasAttr<FinalAttr>())
  return;

CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);

// We can't check dependent instance methods.
if (MD && MD->isInstance() &&
    (MD->getParent()->hasAnyDependentBases() ||
     MD->getType()->isDependentType()))
  return;

if (MD && !MD->isVirtual()) {
  // If we have a non-virtual method, check if if hides a virtual method.
  // (In that case, it's most likely the method has the wrong type.)
  SmallVector<CXXMethodDecl *, 8> OverloadedMethods;
  FindHiddenVirtualMethods(MD, OverloadedMethods);

  if (!OverloadedMethods.empty()) {
    if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
      Diag(OA->getLocation(),
           diag::override_keyword_hides_virtual_member_function)
        << "override" << (OverloadedMethods.size() > 1);
    } else if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
      Diag(FA->getLocation(),
           diag::override_keyword_hides_virtual_member_function)
        << (FA->isSpelledAsSealed() ? "sealed" : "final")
        << (OverloadedMethods.size() > 1);
    }
    NoteHiddenVirtualMethods(MD, OverloadedMethods);
    MD->setInvalidDecl();
    return;
  }
  // Fall through into the general case diagnostic.
  // FIXME: We might want to attempt typo correction here.
}

if (!MD || !MD->isVirtual()) {
  if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
    Diag(OA->getLocation(),
         diag::override_keyword_only_allowed_on_virtual_member_functions)
      << "override" << FixItHint::CreateRemoval(OA->getLocation());
    D->dropAttr<OverrideAttr>();
  }
  if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
    Diag(FA->getLocation(),
         diag::override_keyword_only_allowed_on_virtual_member_functions)
      << (FA->isSpelledAsSealed() ? "sealed" : "final")
      << FixItHint::CreateRemoval(FA->getLocation());
    D->dropAttr<FinalAttr>();
  }
  return;
}

// C++11 [class.virtual]p5:
//   If a function is marked with the virt-specifier override and
//   does not override a member function of a base class, the program is
//   ill-formed.
bool HasOverriddenMethods = MD->size_overridden_methods() != 0;
if (MD->hasAttr<OverrideAttr>() && !HasOverriddenMethods)
  Diag(MD->getLocation(), diag::err_function_marked_override_not_overriding)
    << MD->getDeclName();
3096}

3098void Sema::DiagnoseAbsenceOfOverrideControl(NamedDecl *D, bool Inconsistent) {
if (D->isInvalidDecl() || D->hasAttr<OverrideAttr>())
  return;
CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);
if (!MD || MD->isImplicit() || MD->hasAttr<FinalAttr>())
  return;

SourceLocation Loc = MD->getLocation();
SourceLocation SpellingLoc = Loc;
if (getSourceManager().isMacroArgExpansion(Loc))
  SpellingLoc = getSourceManager().getImmediateExpansionRange(Loc).getBegin();
SpellingLoc = getSourceManager().getSpellingLoc(SpellingLoc);
if (SpellingLoc.isValid() && getSourceManager().isInSystemHeader(SpellingLoc))
    return;

if (MD->size_overridden_methods() > 0) {
  auto EmitDiag = [&](unsigned DiagInconsistent, unsigned DiagSuggest) {
    unsigned DiagID =
        Inconsistent && !Diags.isIgnored(DiagInconsistent, MD->getLocation())
            ? DiagInconsistent
            : DiagSuggest;
    Diag(MD->getLocation(), DiagID) << MD->getDeclName();
    const CXXMethodDecl *OMD = *MD->begin_overridden_methods();
    Diag(OMD->getLocation(), diag::note_overridden_virtual_function);
  };
  if (isa<CXXDestructorDecl>(MD))
    EmitDiag(
        diag::warn_inconsistent_destructor_marked_not_override_overriding,
        diag::warn_suggest_destructor_marked_not_override_overriding);
  else
    EmitDiag(diag::warn_inconsistent_function_marked_not_override_overriding,
             diag::warn_suggest_function_marked_not_override_overriding);
}
3131}

3133/// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
3134/// function overrides a virtual member function marked 'final', according to
3135/// C++11 [class.virtual]p4.
3136bool Sema::CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
                                                const CXXMethodDecl *Old) {
FinalAttr *FA = Old->getAttr<FinalAttr>();
if (!FA)
  return false;

Diag(New->getLocation(), diag::err_final_function_overridden)
  << New->getDeclName()
  << FA->isSpelledAsSealed();
Diag(Old->getLocation(), diag::note_overridden_virtual_function);
return true;
3147}

3149static bool InitializationHasSideEffects(const FieldDecl &FD) {
const Type *T = FD.getType()->getBaseElementTypeUnsafe();
// FIXME: Destruction of ObjC lifetime types has side-effects.
if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
  return !RD->isCompleteDefinition() ||
         !RD->hasTrivialDefaultConstructor() ||
         !RD->hasTrivialDestructor();
return false;
3157}

3159static const ParsedAttr *getMSPropertyAttr(const ParsedAttributesView &list) {
ParsedAttributesView::const_iterator Itr =
    llvm::find_if(list, [](const ParsedAttr &AL) {
      return AL.isDeclspecPropertyAttribute();
    });
if (Itr != list.end())
  return &*Itr;
return nullptr;
3167}

3169// Check if there is a field shadowing.
3170void Sema::CheckShadowInheritedFields(const SourceLocation &Loc,
                                    DeclarationName FieldName,
                                    const CXXRecordDecl *RD,
                                    bool DeclIsField) {
if (Diags.isIgnored(diag::warn_shadow_field, Loc))
  return;

// To record a shadowed field in a base
std::map<CXXRecordDecl*, NamedDecl*> Bases;
auto FieldShadowed = [&](const CXXBaseSpecifier *Specifier,
                         CXXBasePath &Path) {
  const auto Base = Specifier->getType()->getAsCXXRecordDecl();
  // Record an ambiguous path directly
  if (Bases.find(Base) != Bases.end())
    return true;
  for (const auto Field : Base->lookup(FieldName)) {
    if ((isa<FieldDecl>(Field) || isa<IndirectFieldDecl>(Field)) &&
        Field->getAccess() != AS_private) {
      assert(Field->getAccess() != AS_none)((void)0);
      assert(Bases.find(Base) == Bases.end())((void)0);
      Bases[Base] = Field;
      return true;
    }
  }
  return false;
};

CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                   /*DetectVirtual=*/true);
if (!RD->lookupInBases(FieldShadowed, Paths))
  return;

for (const auto &P : Paths) {
  auto Base = P.back().Base->getType()->getAsCXXRecordDecl();
  auto It = Bases.find(Base);
  // Skip duplicated bases
  if (It == Bases.end())
    continue;
  auto BaseField = It->second;
  assert(BaseField->getAccess() != AS_private)((void)0);
  if (AS_none !=
      CXXRecordDecl::MergeAccess(P.Access, BaseField->getAccess())) {
    Diag(Loc, diag::warn_shadow_field)
      << FieldName << RD << Base << DeclIsField;
    Diag(BaseField->getLocation(), diag::note_shadow_field);
    Bases.erase(It);
  }
}
3218}

3220/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
3221/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
3222/// bitfield width if there is one, 'InitExpr' specifies the initializer if
3223/// one has been parsed, and 'InitStyle' is set if an in-class initializer is
3224/// present (but parsing it has been deferred).
3225NamedDecl *
3226Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
                             MultiTemplateParamsArg TemplateParameterLists,
                             Expr *BW, const VirtSpecifiers &VS,
                             InClassInitStyle InitStyle) {
const DeclSpec &DS = D.getDeclSpec();
DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
DeclarationName Name = NameInfo.getName();
SourceLocation Loc = NameInfo.getLoc();

// For anonymous bitfields, the location should point to the type.
if (Loc.isInvalid())
  Loc = D.getBeginLoc();

Expr *BitWidth = static_cast<Expr*>(BW);

assert(isa<CXXRecordDecl>(CurContext))((void)0);
assert(!DS.isFriendSpecified())((void)0);

bool isFunc = D.isDeclarationOfFunction();
const ParsedAttr *MSPropertyAttr =
    getMSPropertyAttr(D.getDeclSpec().getAttributes());

if (cast<CXXRecordDecl>(CurContext)->isInterface()) {
  // The Microsoft extension __interface only permits public member functions
  // and prohibits constructors, destructors, operators, non-public member
  // functions, static methods and data members.
  unsigned InvalidDecl;
  bool ShowDeclName = true;
  if (!isFunc &&
      (DS.getStorageClassSpec() == DeclSpec::SCS_typedef || MSPropertyAttr))
    InvalidDecl = 0;
  else if (!isFunc)
    InvalidDecl = 1;
  else if (AS != AS_public)
    InvalidDecl = 2;
  else if (DS.getStorageClassSpec() == DeclSpec::SCS_static)
    InvalidDecl = 3;
  else switch (Name.getNameKind()) {
    case DeclarationName::CXXConstructorName:
      InvalidDecl = 4;
      ShowDeclName = false;
      break;

    case DeclarationName::CXXDestructorName:
      InvalidDecl = 5;
      ShowDeclName = false;
      break;

    case DeclarationName::CXXOperatorName:
    case DeclarationName::CXXConversionFunctionName:
      InvalidDecl = 6;
      break;

    default:
      InvalidDecl = 0;
      break;
  }

  if (InvalidDecl) {
    if (ShowDeclName)
      Diag(Loc, diag::err_invalid_member_in_interface)
        << (InvalidDecl-1) << Name;
    else
      Diag(Loc, diag::err_invalid_member_in_interface)
        << (InvalidDecl-1) << "";
    return nullptr;
  }
}

// C++ 9.2p6: A member shall not be declared to have automatic storage
// duration (auto, register) or with the extern storage-class-specifier.
// C++ 7.1.1p8: The mutable specifier can be applied only to names of class
// data members and cannot be applied to names declared const or static,
// and cannot be applied to reference members.
switch (DS.getStorageClassSpec()) {
case DeclSpec::SCS_unspecified:
case DeclSpec::SCS_typedef:
case DeclSpec::SCS_static:
  break;
case DeclSpec::SCS_mutable:
  if (isFunc) {
    Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_function);

    // FIXME: It would be nicer if the keyword was ignored only for this
    // declarator. Otherwise we could get follow-up errors.
    D.getMutableDeclSpec().ClearStorageClassSpecs();
  }
  break;
default:
  Diag(DS.getStorageClassSpecLoc(),
       diag::err_storageclass_invalid_for_member);
  D.getMutableDeclSpec().ClearStorageClassSpecs();
  break;
}

bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
                     DS.getStorageClassSpec() == DeclSpec::SCS_mutable) &&
                    !isFunc);

if (DS.hasConstexprSpecifier() && isInstField) {
  SemaDiagnosticBuilder B =
      Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr_member);
  SourceLocation ConstexprLoc = DS.getConstexprSpecLoc();
  if (InitStyle == ICIS_NoInit) {
    B << 0 << 0;
    if (D.getDeclSpec().getTypeQualifiers() & DeclSpec::TQ_const)
      B << FixItHint::CreateRemoval(ConstexprLoc);
    else {
      B << FixItHint::CreateReplacement(ConstexprLoc, "const");
      D.getMutableDeclSpec().ClearConstexprSpec();
      const char *PrevSpec;
      unsigned DiagID;
      bool Failed = D.getMutableDeclSpec().SetTypeQual(
          DeclSpec::TQ_const, ConstexprLoc, PrevSpec, DiagID, getLangOpts());
      (void)Failed;
      assert(!Failed && "Making a constexpr member const shouldn't fail")((void)0);
    }
  } else {
    B << 1;
    const char *PrevSpec;
    unsigned DiagID;
    if (D.getMutableDeclSpec().SetStorageClassSpec(
        *this, DeclSpec::SCS_static, ConstexprLoc, PrevSpec, DiagID,
        Context.getPrintingPolicy())) {
      assert(DS.getStorageClassSpec() == DeclSpec::SCS_mutable &&((void)0)
             "This is the only DeclSpec that should fail to be applied")((void)0);
      B << 1;
    } else {
      B << 0 << FixItHint::CreateInsertion(ConstexprLoc, "static ");
      isInstField = false;
    }
  }
}

NamedDecl *Member;
if (isInstField) {
  CXXScopeSpec &SS = D.getCXXScopeSpec();

  // Data members must have identifiers for names.
  if (!Name.isIdentifier()) {
    Diag(Loc, diag::err_bad_variable_name)
      << Name;
    return nullptr;
  }

  IdentifierInfo *II = Name.getAsIdentifierInfo();

  // Member field could not be with "template" keyword.
  // So TemplateParameterLists should be empty in this case.
  if (TemplateParameterLists.size()) {
    TemplateParameterList* TemplateParams = TemplateParameterLists[0];
    if (TemplateParams->size()) {
      // There is no such thing as a member field template.
      Diag(D.getIdentifierLoc(), diag::err_template_member)
          << II
          << SourceRange(TemplateParams->getTemplateLoc(),
              TemplateParams->getRAngleLoc());
    } else {
      // There is an extraneous 'template<>' for this member.
      Diag(TemplateParams->getTemplateLoc(),
          diag::err_template_member_noparams)
          << II
          << SourceRange(TemplateParams->getTemplateLoc(),
              TemplateParams->getRAngleLoc());
    }
    return nullptr;
  }

  if (SS.isSet() && !SS.isInvalid()) {
    // The user provided a superfluous scope specifier inside a class
    // definition:
    //
    // class X {
    //   int X::member;
    // };
    if (DeclContext *DC = computeDeclContext(SS, false))
      diagnoseQualifiedDeclaration(SS, DC, Name, D.getIdentifierLoc(),
                                   D.getName().getKind() ==
                                       UnqualifiedIdKind::IK_TemplateId);
    else
      Diag(D.getIdentifierLoc(), diag::err_member_qualification)
        << Name << SS.getRange();

    SS.clear();
  }

  if (MSPropertyAttr) {
    Member = HandleMSProperty(S, cast<CXXRecordDecl>(CurContext), Loc, D,
                              BitWidth, InitStyle, AS, *MSPropertyAttr);
    if (!Member)
      return nullptr;
    isInstField = false;
  } else {
    Member = HandleField(S, cast<CXXRecordDecl>(CurContext), Loc, D,
                              BitWidth, InitStyle, AS);
    if (!Member)
      return nullptr;
  }

  CheckShadowInheritedFields(Loc, Name, cast<CXXRecordDecl>(CurContext));
} else {
  Member = HandleDeclarator(S, D, TemplateParameterLists);
  if (!Member)
    return nullptr;

  // Non-instance-fields can't have a bitfield.
  if (BitWidth) {
    if (Member->isInvalidDecl()) {
      // don't emit another diagnostic.
    } else if (isa<VarDecl>(Member) || isa<VarTemplateDecl>(Member)) {
      // C++ 9.6p3: A bit-field shall not be a static member.
      // "static member 'A' cannot be a bit-field"
      Diag(Loc, diag::err_static_not_bitfield)
        << Name << BitWidth->getSourceRange();
    } else if (isa<TypedefDecl>(Member)) {
      // "typedef member 'x' cannot be a bit-field"
      Diag(Loc, diag::err_typedef_not_bitfield)
        << Name << BitWidth->getSourceRange();
    } else {
      // A function typedef ("typedef int f(); f a;").
      // C++ 9.6p3: A bit-field shall have integral or enumeration type.
      Diag(Loc, diag::err_not_integral_type_bitfield)
        << Name << cast<ValueDecl>(Member)->getType()
        << BitWidth->getSourceRange();
    }

    BitWidth = nullptr;
    Member->setInvalidDecl();
  }

  NamedDecl *NonTemplateMember = Member;
  if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Member))
    NonTemplateMember = FunTmpl->getTemplatedDecl();
  else if (VarTemplateDecl *VarTmpl = dyn_cast<VarTemplateDecl>(Member))
    NonTemplateMember = VarTmpl->getTemplatedDecl();

  Member->setAccess(AS);

  // If we have declared a member function template or static data member
  // template, set the access of the templated declaration as well.
  if (NonTemplateMember != Member)
    NonTemplateMember->setAccess(AS);

  // C++ [temp.deduct.guide]p3:
  //   A deduction guide [...] for a member class template [shall be
  //   declared] with the same access [as the template].
  if (auto *DG = dyn_cast<CXXDeductionGuideDecl>(NonTemplateMember)) {
    auto *TD = DG->getDeducedTemplate();
    // Access specifiers are only meaningful if both the template and the
    // deduction guide are from the same scope.
    if (AS != TD->getAccess() &&
        TD->getDeclContext()->getRedeclContext()->Equals(
            DG->getDeclContext()->getRedeclContext())) {
      Diag(DG->getBeginLoc(), diag::err_deduction_guide_wrong_access);
      Diag(TD->getBeginLoc(), diag::note_deduction_guide_template_access)
          << TD->getAccess();
      const AccessSpecDecl *LastAccessSpec = nullptr;
      for (const auto *D : cast<CXXRecordDecl>(CurContext)->decls()) {
        if (const auto *AccessSpec = dyn_cast<AccessSpecDecl>(D))
          LastAccessSpec = AccessSpec;
      }
      assert(LastAccessSpec && "differing access with no access specifier")((void)0);
      Diag(LastAccessSpec->getBeginLoc(), diag::note_deduction_guide_access)
          << AS;
    }
  }
}

if (VS.isOverrideSpecified())
  Member->addAttr(OverrideAttr::Create(Context, VS.getOverrideLoc(),
                                       AttributeCommonInfo::AS_Keyword));
if (VS.isFinalSpecified())
  Member->addAttr(FinalAttr::Create(
      Context, VS.getFinalLoc(), AttributeCommonInfo::AS_Keyword,
      static_cast<FinalAttr::Spelling>(VS.isFinalSpelledSealed())));

if (VS.getLastLocation().isValid()) {
  // Update the end location of a method that has a virt-specifiers.
  if (CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Member))
    MD->setRangeEnd(VS.getLastLocation());
}

CheckOverrideControl(Member);

assert((Name || isInstField) && "No identifier for non-field ?")((void)0);

if (isInstField) {
  FieldDecl *FD = cast<FieldDecl>(Member);
  FieldCollector->Add(FD);

  if (!Diags.isIgnored(diag::warn_unused_private_field, FD->getLocation())) {
    // Remember all explicit private FieldDecls that have a name, no side
    // effects and are not part of a dependent type declaration.
    if (!FD->isImplicit() && FD->getDeclName() &&
        FD->getAccess() == AS_private &&
        !FD->hasAttr<UnusedAttr>() &&
        !FD->getParent()->isDependentContext() &&
        !InitializationHasSideEffects(*FD))
      UnusedPrivateFields.insert(FD);
  }
}

return Member;
3529}

3531namespace {
class UninitializedFieldVisitor
    : public EvaluatedExprVisitor<UninitializedFieldVisitor> {
  Sema &S;
  // List of Decls to generate a warning on.  Also remove Decls that become
  // initialized.
  llvm::SmallPtrSetImpl<ValueDecl*> &Decls;
  // List of base classes of the record.  Classes are removed after their
  // initializers.
  llvm::SmallPtrSetImpl<QualType> &BaseClasses;
  // Vector of decls to be removed from the Decl set prior to visiting the
  // nodes.  These Decls may have been initialized in the prior initializer.
  llvm::SmallVector<ValueDecl*, 4> DeclsToRemove;
  // If non-null, add a note to the warning pointing back to the constructor.
  const CXXConstructorDecl *Constructor;
  // Variables to hold state when processing an initializer list.  When
  // InitList is true, special case initialization of FieldDecls matching
  // InitListFieldDecl.
  bool InitList;
  FieldDecl *InitListFieldDecl;
  llvm::SmallVector<unsigned, 4> InitFieldIndex;

public:
  typedef EvaluatedExprVisitor<UninitializedFieldVisitor> Inherited;
  UninitializedFieldVisitor(Sema &S,
                            llvm::SmallPtrSetImpl<ValueDecl*> &Decls,
                            llvm::SmallPtrSetImpl<QualType> &BaseClasses)
    : Inherited(S.Context), S(S), Decls(Decls), BaseClasses(BaseClasses),
      Constructor(nullptr), InitList(false), InitListFieldDecl(nullptr) {}

  // Returns true if the use of ME is not an uninitialized use.
  bool IsInitListMemberExprInitialized(MemberExpr *ME,
                                       bool CheckReferenceOnly) {
    llvm::SmallVector<FieldDecl*, 4> Fields;
    bool ReferenceField = false;
    while (ME) {
      FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
      if (!FD)
        return false;
      Fields.push_back(FD);
      if (FD->getType()->isReferenceType())
        ReferenceField = true;
      ME = dyn_cast<MemberExpr>(ME->getBase()->IgnoreParenImpCasts());
    }

    // Binding a reference to an uninitialized field is not an
    // uninitialized use.
    if (CheckReferenceOnly && !ReferenceField)
      return true;

    llvm::SmallVector<unsigned, 4> UsedFieldIndex;
    // Discard the first field since it is the field decl that is being
    // initialized.
    for (auto I = Fields.rbegin() + 1, E = Fields.rend(); I != E; ++I) {
      UsedFieldIndex.push_back((*I)->getFieldIndex());
    }

    for (auto UsedIter = UsedFieldIndex.begin(),
              UsedEnd = UsedFieldIndex.end(),
              OrigIter = InitFieldIndex.begin(),
              OrigEnd = InitFieldIndex.end();
         UsedIter != UsedEnd && OrigIter != OrigEnd; ++UsedIter, ++OrigIter) {
      if (*UsedIter < *OrigIter)
        return true;
      if (*UsedIter > *OrigIter)
        break;
    }

    return false;
  }

  void HandleMemberExpr(MemberExpr *ME, bool CheckReferenceOnly,
                        bool AddressOf) {
    if (isa<EnumConstantDecl>(ME->getMemberDecl()))
      return;

    // FieldME is the inner-most MemberExpr that is not an anonymous struct
    // or union.
    MemberExpr *FieldME = ME;

    bool AllPODFields = FieldME->getType().isPODType(S.Context);

    Expr *Base = ME;
    while (MemberExpr *SubME =
               dyn_cast<MemberExpr>(Base->IgnoreParenImpCasts())) {

      if (isa<VarDecl>(SubME->getMemberDecl()))
        return;

      if (FieldDecl *FD = dyn_cast<FieldDecl>(SubME->getMemberDecl()))
        if (!FD->isAnonymousStructOrUnion())
          FieldME = SubME;

      if (!FieldME->getType().isPODType(S.Context))
        AllPODFields = false;

      Base = SubME->getBase();
    }

    if (!isa<CXXThisExpr>(Base->IgnoreParenImpCasts())) {
      Visit(Base);
      return;
    }

    if (AddressOf && AllPODFields)
      return;

    ValueDecl* FoundVD = FieldME->getMemberDecl();

    if (ImplicitCastExpr *BaseCast = dyn_cast<ImplicitCastExpr>(Base)) {
      while (isa<ImplicitCastExpr>(BaseCast->getSubExpr())) {
        BaseCast = cast<ImplicitCastExpr>(BaseCast->getSubExpr());
      }

      if (BaseCast->getCastKind() == CK_UncheckedDerivedToBase) {
        QualType T = BaseCast->getType();
        if (T->isPointerType() &&
            BaseClasses.count(T->getPointeeType())) {
          S.Diag(FieldME->getExprLoc(), diag::warn_base_class_is_uninit)
              << T->getPointeeType() << FoundVD;
        }
      }
    }

    if (!Decls.count(FoundVD))
      return;

    const bool IsReference = FoundVD->getType()->isReferenceType();

    if (InitList && !AddressOf && FoundVD == InitListFieldDecl) {
      // Special checking for initializer lists.
      if (IsInitListMemberExprInitialized(ME, CheckReferenceOnly)) {
        return;
      }
    } else {
      // Prevent double warnings on use of unbounded references.
      if (CheckReferenceOnly && !IsReference)
        return;
    }

    unsigned diag = IsReference
        ? diag::warn_reference_field_is_uninit
        : diag::warn_field_is_uninit;
    S.Diag(FieldME->getExprLoc(), diag) << FoundVD;
    if (Constructor)
      S.Diag(Constructor->getLocation(),
             diag::note_uninit_in_this_constructor)
        << (Constructor->isDefaultConstructor() && Constructor->isImplicit());

  }

  void HandleValue(Expr *E, bool AddressOf) {
    E = E->IgnoreParens();

    if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
      HandleMemberExpr(ME, false /*CheckReferenceOnly*/,
                       AddressOf /*AddressOf*/);
      return;
    }

    if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
      Visit(CO->getCond());
      HandleValue(CO->getTrueExpr(), AddressOf);
      HandleValue(CO->getFalseExpr(), AddressOf);
      return;
    }

    if (BinaryConditionalOperator *BCO =
            dyn_cast<BinaryConditionalOperator>(E)) {
      Visit(BCO->getCond());
      HandleValue(BCO->getFalseExpr(), AddressOf);
      return;
    }

    if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
      HandleValue(OVE->getSourceExpr(), AddressOf);
      return;
    }

    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
      switch (BO->getOpcode()) {
      default:
        break;
      case(BO_PtrMemD):
      case(BO_PtrMemI):
        HandleValue(BO->getLHS(), AddressOf);
        Visit(BO->getRHS());
        return;
      case(BO_Comma):
        Visit(BO->getLHS());
        HandleValue(BO->getRHS(), AddressOf);
        return;
      }
    }

    Visit(E);
  }

  void CheckInitListExpr(InitListExpr *ILE) {
    InitFieldIndex.push_back(0);
    for (auto Child : ILE->children()) {
      if (InitListExpr *SubList = dyn_cast<InitListExpr>(Child)) {
        CheckInitListExpr(SubList);
      } else {
        Visit(Child);
      }
      ++InitFieldIndex.back();
    }
    InitFieldIndex.pop_back();
  }

  void CheckInitializer(Expr *E, const CXXConstructorDecl *FieldConstructor,
                        FieldDecl *Field, const Type *BaseClass) {
    // Remove Decls that may have been initialized in the previous
    // initializer.
    for (ValueDecl* VD : DeclsToRemove)
      Decls.erase(VD);
    DeclsToRemove.clear();

    Constructor = FieldConstructor;
    InitListExpr *ILE = dyn_cast<InitListExpr>(E);

    if (ILE && Field) {
      InitList = true;
      InitListFieldDecl = Field;
      InitFieldIndex.clear();
      CheckInitListExpr(ILE);
    } else {
      InitList = false;
      Visit(E);
    }

    if (Field)
      Decls.erase(Field);
    if (BaseClass)
      BaseClasses.erase(BaseClass->getCanonicalTypeInternal());
  }

  void VisitMemberExpr(MemberExpr *ME) {
    // All uses of unbounded reference fields will warn.
    HandleMemberExpr(ME, true /*CheckReferenceOnly*/, false /*AddressOf*/);
  }

  void VisitImplicitCastExpr(ImplicitCastExpr *E) {
    if (E->getCastKind() == CK_LValueToRValue) {
      HandleValue(E->getSubExpr(), false /*AddressOf*/);
      return;
    }

    Inherited::VisitImplicitCastExpr(E);
  }

  void VisitCXXConstructExpr(CXXConstructExpr *E) {
    if (E->getConstructor()->isCopyConstructor()) {
      Expr *ArgExpr = E->getArg(0);
      if (InitListExpr *ILE = dyn_cast<InitListExpr>(ArgExpr))
        if (ILE->getNumInits() == 1)
          ArgExpr = ILE->getInit(0);
      if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
        if (ICE->getCastKind() == CK_NoOp)
          ArgExpr = ICE->getSubExpr();
      HandleValue(ArgExpr, false /*AddressOf*/);
      return;
    }
    Inherited::VisitCXXConstructExpr(E);
  }

  void VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
    Expr *Callee = E->getCallee();
    if (isa<MemberExpr>(Callee)) {
      HandleValue(Callee, false /*AddressOf*/);
      for (auto Arg : E->arguments())
        Visit(Arg);
      return;
    }

    Inherited::VisitCXXMemberCallExpr(E);
  }

  void VisitCallExpr(CallExpr *E) {
    // Treat std::move as a use.
    if (E->isCallToStdMove()) {
      HandleValue(E->getArg(0), /*AddressOf=*/false);
      return;
    }

    Inherited::VisitCallExpr(E);
  }

  void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
    Expr *Callee = E->getCallee();

    if (isa<UnresolvedLookupExpr>(Callee))
      return Inherited::VisitCXXOperatorCallExpr(E);

    Visit(Callee);
    for (auto Arg : E->arguments())
      HandleValue(Arg->IgnoreParenImpCasts(), false /*AddressOf*/);
  }

  void VisitBinaryOperator(BinaryOperator *E) {
    // If a field assignment is detected, remove the field from the
    // uninitiailized field set.
    if (E->getOpcode() == BO_Assign)
      if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getLHS()))
        if (FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
          if (!FD->getType()->isReferenceType())
            DeclsToRemove.push_back(FD);

    if (E->isCompoundAssignmentOp()) {
      HandleValue(E->getLHS(), false /*AddressOf*/);
      Visit(E->getRHS());
      return;
    }

    Inherited::VisitBinaryOperator(E);
  }

  void VisitUnaryOperator(UnaryOperator *E) {
    if (E->isIncrementDecrementOp()) {
      HandleValue(E->getSubExpr(), false /*AddressOf*/);
      return;
    }
    if (E->getOpcode() == UO_AddrOf) {
      if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getSubExpr())) {
        HandleValue(ME->getBase(), true /*AddressOf*/);
        return;
      }
    }

    Inherited::VisitUnaryOperator(E);
  }
};

// Diagnose value-uses of fields to initialize themselves, e.g.
//   foo(foo)
// where foo is not also a parameter to the constructor.
// Also diagnose across field uninitialized use such as
//   x(y), y(x)
// TODO: implement -Wuninitialized and fold this into that framework.
static void DiagnoseUninitializedFields(
    Sema &SemaRef, const CXXConstructorDecl *Constructor) {

  if (SemaRef.getDiagnostics().isIgnored(diag::warn_field_is_uninit,
                                         Constructor->getLocation())) {
    return;
  }

  if (Constructor->isInvalidDecl())
    return;

  const CXXRecordDecl *RD = Constructor->getParent();

  if (RD->isDependentContext())
    return;

  // Holds fields that are uninitialized.
  llvm::SmallPtrSet<ValueDecl*, 4> UninitializedFields;

  // At the beginning, all fields are uninitialized.
  for (auto *I : RD->decls()) {
    if (auto *FD = dyn_cast<FieldDecl>(I)) {
      UninitializedFields.insert(FD);
    } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(I)) {
      UninitializedFields.insert(IFD->getAnonField());
    }
  }

  llvm::SmallPtrSet<QualType, 4> UninitializedBaseClasses;
  for (auto I : RD->bases())
    UninitializedBaseClasses.insert(I.getType().getCanonicalType());

  if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
    return;

  UninitializedFieldVisitor UninitializedChecker(SemaRef,
                                                 UninitializedFields,
                                                 UninitializedBaseClasses);

  for (const auto *FieldInit : Constructor->inits()) {
    if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
      break;

    Expr *InitExpr = FieldInit->getInit();
    if (!InitExpr)
      continue;

    if (CXXDefaultInitExpr *Default =
            dyn_cast<CXXDefaultInitExpr>(InitExpr)) {
      InitExpr = Default->getExpr();
      if (!InitExpr)
        continue;
      // In class initializers will point to the constructor.
      UninitializedChecker.CheckInitializer(InitExpr, Constructor,
                                            FieldInit->getAnyMember(),
                                            FieldInit->getBaseClass());
    } else {
      UninitializedChecker.CheckInitializer(InitExpr, nullptr,
                                            FieldInit->getAnyMember(),
                                            FieldInit->getBaseClass());
    }
  }
}
3934} // namespace

3936/// Enter a new C++ default initializer scope. After calling this, the
3937/// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
3938/// parsing or instantiating the initializer failed.
3939void Sema::ActOnStartCXXInClassMemberInitializer() {
// Create a synthetic function scope to represent the call to the constructor
// that notionally surrounds a use of this initializer.
PushFunctionScope();
3943}

3945void Sema::ActOnStartTrailingRequiresClause(Scope *S, Declarator &D) {
if (!D.isFunctionDeclarator())
  return;
auto &FTI = D.getFunctionTypeInfo();
if (!FTI.Params)
  return;
for (auto &Param : ArrayRef<DeclaratorChunk::ParamInfo>(FTI.Params,
                                                        FTI.NumParams)) {
  auto *ParamDecl = cast<NamedDecl>(Param.Param);
  if (ParamDecl->getDeclName())
    PushOnScopeChains(ParamDecl, S, /*AddToContext=*/false);
}
3957}

3959ExprResult Sema::ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr) {
return ActOnRequiresClause(ConstraintExpr);
3961}

3963ExprResult Sema::ActOnRequiresClause(ExprResult ConstraintExpr) {
if (ConstraintExpr.isInvalid())
  return ExprError();

ConstraintExpr = CorrectDelayedTyposInExpr(ConstraintExpr);
if (ConstraintExpr.isInvalid())
  return ExprError();

if (DiagnoseUnexpandedParameterPack(ConstraintExpr.get(),
                                    UPPC_RequiresClause))
  return ExprError();

return ConstraintExpr;
3976}

3978/// This is invoked after parsing an in-class initializer for a
3979/// non-static C++ class member, and after instantiating an in-class initializer
3980/// in a class template. Such actions are deferred until the class is complete.
3981void Sema::ActOnFinishCXXInClassMemberInitializer(Decl *D,
                                                SourceLocation InitLoc,
                                                Expr *InitExpr) {
// Pop the notional constructor scope we created earlier.
PopFunctionScopeInfo(nullptr, D);

FieldDecl *FD = dyn_cast<FieldDecl>(D);
assert((isa<MSPropertyDecl>(D) || FD->getInClassInitStyle() != ICIS_NoInit) &&((void)0)
       "must set init style when field is created")((void)0);

if (!InitExpr) {
  D->setInvalidDecl();
  if (FD)
    FD->removeInClassInitializer();
  return;
}

if (DiagnoseUnexpandedParameterPack(InitExpr, UPPC_Initializer)) {
  FD->setInvalidDecl();
  FD->removeInClassInitializer();
  return;
}

ExprResult Init = InitExpr;
if (!FD->getType()->isDependentType() && !InitExpr->isTypeDependent()) {
  InitializedEntity Entity =
      InitializedEntity::InitializeMemberFromDefaultMemberInitializer(FD);
  InitializationKind Kind =
      FD->getInClassInitStyle() == ICIS_ListInit
          ? InitializationKind::CreateDirectList(InitExpr->getBeginLoc(),
                                                 InitExpr->getBeginLoc(),
                                                 InitExpr->getEndLoc())
          : InitializationKind::CreateCopy(InitExpr->getBeginLoc(), InitLoc);
  InitializationSequence Seq(*this, Entity, Kind, InitExpr);
  Init = Seq.Perform(*this, Entity, Kind, InitExpr);
  if (Init.isInvalid()) {
    FD->setInvalidDecl();
    return;
  }
}

// C++11 [class.base.init]p7:
//   The initialization of each base and member constitutes a
//   full-expression.
Init = ActOnFinishFullExpr(Init.get(), InitLoc, /*DiscardedValue*/ false);
if (Init.isInvalid()) {
  FD->setInvalidDecl();
  return;
}

InitExpr = Init.get();

FD->setInClassInitializer(InitExpr);
4034}

4036/// Find the direct and/or virtual base specifiers that
4037/// correspond to the given base type, for use in base initialization
4038/// within a constructor.
4039static bool FindBaseInitializer(Sema &SemaRef,
                              CXXRecordDecl *ClassDecl,
                              QualType BaseType,
                              const CXXBaseSpecifier *&DirectBaseSpec,
                              const CXXBaseSpecifier *&VirtualBaseSpec) {
// First, check for a direct base class.
DirectBaseSpec = nullptr;
for (const auto &Base : ClassDecl->bases()) {
  if (SemaRef.Context.hasSameUnqualifiedType(BaseType, Base.getType())) {
    // We found a direct base of this type. That's what we're
    // initializing.
    DirectBaseSpec = &Base;
    break;
  }
}

// Check for a virtual base class.
// FIXME: We might be able to short-circuit this if we know in advance that
// there are no virtual bases.
VirtualBaseSpec = nullptr;
if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) {
  // We haven't found a base yet; search the class hierarchy for a
  // virtual base class.
  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                     /*DetectVirtual=*/false);
  if (SemaRef.IsDerivedFrom(ClassDecl->getLocation(),
                            SemaRef.Context.getTypeDeclType(ClassDecl),
                            BaseType, Paths)) {
    for (CXXBasePaths::paths_iterator Path = Paths.begin();
         Path != Paths.end(); ++Path) {
      if (Path->back().Base->isVirtual()) {
        VirtualBaseSpec = Path->back().Base;
        break;
      }
    }
  }
}

return DirectBaseSpec || VirtualBaseSpec;
4078}

4080/// Handle a C++ member initializer using braced-init-list syntax.
4081MemInitResult
4082Sema::ActOnMemInitializer(Decl *ConstructorD,
                        Scope *S,
                        CXXScopeSpec &SS,
                        IdentifierInfo *MemberOrBase,
                        ParsedType TemplateTypeTy,
                        const DeclSpec &DS,
                        SourceLocation IdLoc,
                        Expr *InitList,
                        SourceLocation EllipsisLoc) {
return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
                           DS, IdLoc, InitList,
                           EllipsisLoc);
4094}

4096/// Handle a C++ member initializer using parentheses syntax.
4097MemInitResult
4098Sema::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) {
Expr *List = ParenListExpr::Create(Context, LParenLoc, Args, RParenLoc);
return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
                           DS, IdLoc, List, EllipsisLoc);
4112}

4114namespace {

4116// Callback to only accept typo corrections that can be a valid C++ member
4117// intializer: either a non-static field member or a base class.
4118class MemInitializerValidatorCCC final : public CorrectionCandidateCallback {
4119public:
explicit MemInitializerValidatorCCC(CXXRecordDecl *ClassDecl)
    : ClassDecl(ClassDecl) {}

bool ValidateCandidate(const TypoCorrection &candidate) override {
  if (NamedDecl *ND = candidate.getCorrectionDecl()) {
    if (FieldDecl *Member = dyn_cast<FieldDecl>(ND))
      return Member->getDeclContext()->getRedeclContext()->Equals(ClassDecl);
    return isa<TypeDecl>(ND);
  }
  return false;
}

std::unique_ptr<CorrectionCandidateCallback> clone() override {
  return std::make_unique<MemInitializerValidatorCCC>(*this);
}

4136private:
CXXRecordDecl *ClassDecl;
4138};

4140}

4142ValueDecl *Sema::tryLookupCtorInitMemberDecl(CXXRecordDecl *ClassDecl,
                                           CXXScopeSpec &SS,
                                           ParsedType TemplateTypeTy,
                                           IdentifierInfo *MemberOrBase) {
if (SS.getScopeRep() || TemplateTypeTy)
  return nullptr;
for (auto *D : ClassDecl->lookup(MemberOrBase))
  if (isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D))
    return cast<ValueDecl>(D);
return nullptr;
4152}

4154/// Handle a C++ member initializer.
4155MemInitResult
4156Sema::BuildMemInitializer(Decl *ConstructorD,
                        Scope *S,
                        CXXScopeSpec &SS,
                        IdentifierInfo *MemberOrBase,
                        ParsedType TemplateTypeTy,
                        const DeclSpec &DS,
                        SourceLocation IdLoc,
                        Expr *Init,
                        SourceLocation EllipsisLoc) {
ExprResult Res = CorrectDelayedTyposInExpr(Init);
if (!Res.isUsable())
  return true;
Init = Res.get();

if (!ConstructorD)
  return true;

AdjustDeclIfTemplate(ConstructorD);

CXXConstructorDecl *Constructor
  = dyn_cast<CXXConstructorDecl>(ConstructorD);
if (!Constructor) {
  // The user wrote a constructor initializer on a function that is
  // not a C++ constructor. Ignore the error for now, because we may
  // have more member initializers coming; we'll diagnose it just
  // once in ActOnMemInitializers.
  return true;
}

CXXRecordDecl *ClassDecl = Constructor->getParent();

// C++ [class.base.init]p2:
//   Names in a mem-initializer-id are looked up in the scope of the
//   constructor's class and, if not found in that scope, are looked
//   up in the scope containing the constructor's definition.
//   [Note: if the constructor's class contains a member with the
//   same name as a direct or virtual base class of the class, a
//   mem-initializer-id naming the member or base class and composed
//   of a single identifier refers to the class member. A
//   mem-initializer-id for the hidden base class may be specified
//   using a qualified name. ]

// Look for a member, first.
if (ValueDecl *Member = tryLookupCtorInitMemberDecl(
        ClassDecl, SS, TemplateTypeTy, MemberOrBase)) {
  if (EllipsisLoc.isValid())
    Diag(EllipsisLoc, diag::err_pack_expansion_member_init)
        << MemberOrBase
        << SourceRange(IdLoc, Init->getSourceRange().getEnd());

  return BuildMemberInitializer(Member, Init, IdLoc);
}
// It didn't name a member, so see if it names a class.
QualType BaseType;
TypeSourceInfo *TInfo = nullptr;

if (TemplateTypeTy) {
  BaseType = GetTypeFromParser(TemplateTypeTy, &TInfo);
  if (BaseType.isNull())
    return true;
} else if (DS.getTypeSpecType() == TST_decltype) {
  BaseType = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
} else if (DS.getTypeSpecType() == TST_decltype_auto) {
  Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
  return true;
} else {
  LookupResult R(*this, MemberOrBase, IdLoc, LookupOrdinaryName);
  LookupParsedName(R, S, &SS);

  TypeDecl *TyD = R.getAsSingle<TypeDecl>();
  if (!TyD) {
    if (R.isAmbiguous()) return true;

    // We don't want access-control diagnostics here.
    R.suppressDiagnostics();

    if (SS.isSet() && isDependentScopeSpecifier(SS)) {
      bool NotUnknownSpecialization = false;
      DeclContext *DC = computeDeclContext(SS, false);
      if (CXXRecordDecl *Record = dyn_cast_or_null<CXXRecordDecl>(DC))
        NotUnknownSpecialization = !Record->hasAnyDependentBases();

      if (!NotUnknownSpecialization) {
        // When the scope specifier can refer to a member of an unknown
        // specialization, we take it as a type name.
        BaseType = CheckTypenameType(ETK_None, SourceLocation(),
                                     SS.getWithLocInContext(Context),
                                     *MemberOrBase, IdLoc);
        if (BaseType.isNull())
          return true;

        TInfo = Context.CreateTypeSourceInfo(BaseType);
        DependentNameTypeLoc TL =
            TInfo->getTypeLoc().castAs<DependentNameTypeLoc>();
        if (!TL.isNull()) {
          TL.setNameLoc(IdLoc);
          TL.setElaboratedKeywordLoc(SourceLocation());
          TL.setQualifierLoc(SS.getWithLocInContext(Context));
        }

        R.clear();
        R.setLookupName(MemberOrBase);
      }
    }

    // If no results were found, try to correct typos.
    TypoCorrection Corr;
    MemInitializerValidatorCCC CCC(ClassDecl);
    if (R.empty() && BaseType.isNull() &&
        (Corr = CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, &SS,
                            CCC, CTK_ErrorRecovery, ClassDecl))) {
      if (FieldDecl *Member = Corr.getCorrectionDeclAs<FieldDecl>()) {
        // We have found a non-static data member with a similar
        // name to what was typed; complain and initialize that
        // member.
        diagnoseTypo(Corr,
                     PDiag(diag::err_mem_init_not_member_or_class_suggest)
                       << MemberOrBase << true);
        return BuildMemberInitializer(Member, Init, IdLoc);
      } else if (TypeDecl *Type = Corr.getCorrectionDeclAs<TypeDecl>()) {
        const CXXBaseSpecifier *DirectBaseSpec;
        const CXXBaseSpecifier *VirtualBaseSpec;
        if (FindBaseInitializer(*this, ClassDecl,
                                Context.getTypeDeclType(Type),
                                DirectBaseSpec, VirtualBaseSpec)) {
          // We have found a direct or virtual base class with a
          // similar name to what was typed; complain and initialize
          // that base class.
          diagnoseTypo(Corr,
                       PDiag(diag::err_mem_init_not_member_or_class_suggest)
                         << MemberOrBase << false,
                       PDiag() /*Suppress note, we provide our own.*/);

          const CXXBaseSpecifier *BaseSpec = DirectBaseSpec ? DirectBaseSpec
                                                            : VirtualBaseSpec;
          Diag(BaseSpec->getBeginLoc(), diag::note_base_class_specified_here)
              << BaseSpec->getType() << BaseSpec->getSourceRange();

          TyD = Type;
        }
      }
    }

    if (!TyD && BaseType.isNull()) {
      Diag(IdLoc, diag::err_mem_init_not_member_or_class)
        << MemberOrBase << SourceRange(IdLoc,Init->getSourceRange().getEnd());
      return true;
    }
  }

  if (BaseType.isNull()) {
    BaseType = Context.getTypeDeclType(TyD);
    MarkAnyDeclReferenced(TyD->getLocation(), TyD, /*OdrUse=*/false);
    if (SS.isSet()) {
      BaseType = Context.getElaboratedType(ETK_None, SS.getScopeRep(),
                                           BaseType);
      TInfo = Context.CreateTypeSourceInfo(BaseType);
      ElaboratedTypeLoc TL = TInfo->getTypeLoc().castAs<ElaboratedTypeLoc>();
      TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
      TL.setElaboratedKeywordLoc(SourceLocation());
      TL.setQualifierLoc(SS.getWithLocInContext(Context));
    }
  }
}

if (!TInfo)
  TInfo = Context.getTrivialTypeSourceInfo(BaseType, IdLoc);

return BuildBaseInitializer(BaseType, TInfo, Init, ClassDecl, EllipsisLoc);
4325}

4327MemInitResult
4328Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
                           SourceLocation IdLoc) {
FieldDecl *DirectMember = dyn_cast<FieldDecl>(Member);
IndirectFieldDecl *IndirectMember = dyn_cast<IndirectFieldDecl>(Member);
assert((DirectMember || IndirectMember) &&((void)0)
       "Member must be a FieldDecl or IndirectFieldDecl")((void)0);

if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
  return true;

if (Member->isInvalidDecl())
  return true;

MultiExprArg Args;
if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
} else if (InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
  Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
} else {
  // Template instantiation doesn't reconstruct ParenListExprs for us.
  Args = Init;
}

SourceRange InitRange = Init->getSourceRange();

if (Member->getType()->isDependentType() || Init->isTypeDependent()) {
  // Can't check initialization for a member of dependent type or when
  // any of the arguments are type-dependent expressions.
  DiscardCleanupsInEvaluationContext();
} else {
  bool InitList = false;
  if (isa<InitListExpr>(Init)) {
    InitList = true;
    Args = Init;
  }

  // Initialize the member.
  InitializedEntity MemberEntity =
    DirectMember ? InitializedEntity::InitializeMember(DirectMember, nullptr)
                 : InitializedEntity::InitializeMember(IndirectMember,
                                                       nullptr);
  InitializationKind Kind =
      InitList ? InitializationKind::CreateDirectList(
                     IdLoc, Init->getBeginLoc(), Init->getEndLoc())
               : InitializationKind::CreateDirect(IdLoc, InitRange.getBegin(),
                                                  InitRange.getEnd());

  InitializationSequence InitSeq(*this, MemberEntity, Kind, Args);
  ExprResult MemberInit = InitSeq.Perform(*this, MemberEntity, Kind, Args,
                                          nullptr);
  if (MemberInit.isInvalid())
    return true;

  // C++11 [class.base.init]p7:
  //   The initialization of each base and member constitutes a
  //   full-expression.
  MemberInit = ActOnFinishFullExpr(MemberInit.get(), InitRange.getBegin(),
                                   /*DiscardedValue*/ false);
  if (MemberInit.isInvalid())
    return true;

  Init = MemberInit.get();
}

if (DirectMember) {
  return new (Context) CXXCtorInitializer(Context, DirectMember, IdLoc,
                                          InitRange.getBegin(), Init,
                                          InitRange.getEnd());
} else {
  return new (Context) CXXCtorInitializer(Context, IndirectMember, IdLoc,
                                          InitRange.getBegin(), Init,
                                          InitRange.getEnd());
}
4401}

4403MemInitResult
4404Sema::BuildDelegatingInitializer(TypeSourceInfo *TInfo, Expr *Init,
                               CXXRecordDecl *ClassDecl) {
SourceLocation NameLoc = TInfo->getTypeLoc().getLocalSourceRange().getBegin();
if (!LangOpts.CPlusPlus11)
  return Diag(NameLoc, diag::err_delegating_ctor)
    << TInfo->getTypeLoc().getLocalSourceRange();
Diag(NameLoc, diag::warn_cxx98_compat_delegating_ctor);

bool InitList = true;
MultiExprArg Args = Init;
if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
  InitList = false;
  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
}

SourceRange InitRange = Init->getSourceRange();
// Initialize the object.
InitializedEntity DelegationEntity = InitializedEntity::InitializeDelegation(
                                   QualType(ClassDecl->getTypeForDecl(), 0));
InitializationKind Kind =
    InitList ? InitializationKind::CreateDirectList(
                   NameLoc, Init->getBeginLoc(), Init->getEndLoc())
             : InitializationKind::CreateDirect(NameLoc, InitRange.getBegin(),
                                                InitRange.getEnd());
InitializationSequence InitSeq(*this, DelegationEntity, Kind, Args);
ExprResult DelegationInit = InitSeq.Perform(*this, DelegationEntity, Kind,
                                            Args, nullptr);
if (DelegationInit.isInvalid())
  return true;

assert(cast<CXXConstructExpr>(DelegationInit.get())->getConstructor() &&((void)0)
       "Delegating constructor with no target?")((void)0);

// C++11 [class.base.init]p7:
//   The initialization of each base and member constitutes a
//   full-expression.
DelegationInit = ActOnFinishFullExpr(
    DelegationInit.get(), InitRange.getBegin(), /*DiscardedValue*/ false);
if (DelegationInit.isInvalid())
  return true;

// If we are in a dependent context, template instantiation will
// perform this type-checking again. Just save the arguments that we
// received in a ParenListExpr.
// FIXME: This isn't quite ideal, since our ASTs don't capture all
// of the information that we have about the base
// initializer. However, deconstructing the ASTs is a dicey process,
// and this approach is far more likely to get the corner cases right.
if (CurContext->isDependentContext())
  DelegationInit = Init;

return new (Context) CXXCtorInitializer(Context, TInfo, InitRange.getBegin(),
                                        DelegationInit.getAs<Expr>(),
                                        InitRange.getEnd());
4458}

4460MemInitResult
4461Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
                         Expr *Init, CXXRecordDecl *ClassDecl,
                         SourceLocation EllipsisLoc) {
SourceLocation BaseLoc
  = BaseTInfo->getTypeLoc().getLocalSourceRange().getBegin();

if (!BaseType->isDependentType() && !BaseType->isRecordType())
  return Diag(BaseLoc, diag::err_base_init_does_not_name_class)
           << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();

// C++ [class.base.init]p2:
//   [...] Unless the mem-initializer-id names a nonstatic data
//   member of the constructor's class or a direct or virtual base
//   of that class, the mem-initializer is ill-formed. A
//   mem-initializer-list can initialize a base class using any
//   name that denotes that base class type.
bool Dependent = BaseType->isDependentType() || Init->isTypeDependent();

SourceRange InitRange = Init->getSourceRange();
if (EllipsisLoc.isValid()) {
  // This is a pack expansion.
  if (!BaseType->containsUnexpandedParameterPack())  {
    Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
      << SourceRange(BaseLoc, InitRange.getEnd());

    EllipsisLoc = SourceLocation();
  }
} else {
  // Check for any unexpanded parameter packs.
  if (DiagnoseUnexpandedParameterPack(BaseLoc, BaseTInfo, UPPC_Initializer))
    return true;

  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
    return true;
}

// Check for direct and virtual base classes.
const CXXBaseSpecifier *DirectBaseSpec = nullptr;
const CXXBaseSpecifier *VirtualBaseSpec = nullptr;
if (!Dependent) {
  if (Context.hasSameUnqualifiedType(QualType(ClassDecl->getTypeForDecl(),0),
                                     BaseType))
    return BuildDelegatingInitializer(BaseTInfo, Init, ClassDecl);

  FindBaseInitializer(*this, ClassDecl, BaseType, DirectBaseSpec,
                      VirtualBaseSpec);

  // C++ [base.class.init]p2:
  // Unless the mem-initializer-id names a nonstatic data member of the
  // constructor's class or a direct or virtual base of that class, the
  // mem-initializer is ill-formed.
  if (!DirectBaseSpec && !VirtualBaseSpec) {
    // If the class has any dependent bases, then it's possible that
    // one of those types will resolve to the same type as
    // BaseType. Therefore, just treat this as a dependent base
    // class initialization.  FIXME: Should we try to check the
    // initialization anyway? It seems odd.
    if (ClassDecl->hasAnyDependentBases())
      Dependent = true;
    else
      return Diag(BaseLoc, diag::err_not_direct_base_or_virtual)
        << BaseType << Context.getTypeDeclType(ClassDecl)
        << BaseTInfo->getTypeLoc().getLocalSourceRange();
  }
}

if (Dependent) {
  DiscardCleanupsInEvaluationContext();

  return new (Context) CXXCtorInitializer(Context, BaseTInfo,
                                          /*IsVirtual=*/false,
                                          InitRange.getBegin(), Init,
                                          InitRange.getEnd(), EllipsisLoc);
}

// C++ [base.class.init]p2:
//   If a mem-initializer-id is ambiguous because it designates both
//   a direct non-virtual base class and an inherited virtual base
//   class, the mem-initializer is ill-formed.
if (DirectBaseSpec && VirtualBaseSpec)
  return Diag(BaseLoc, diag::err_base_init_direct_and_virtual)
    << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();

const CXXBaseSpecifier *BaseSpec = DirectBaseSpec;
if (!BaseSpec)
  BaseSpec = VirtualBaseSpec;

// Initialize the base.
bool InitList = true;
MultiExprArg Args = Init;
if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
  InitList = false;
  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
}

InitializedEntity BaseEntity =
  InitializedEntity::InitializeBase(Context, BaseSpec, VirtualBaseSpec);
InitializationKind Kind =
    InitList ? InitializationKind::CreateDirectList(BaseLoc)
             : InitializationKind::CreateDirect(BaseLoc, InitRange.getBegin(),
                                                InitRange.getEnd());
InitializationSequence InitSeq(*this, BaseEntity, Kind, Args);
ExprResult BaseInit = InitSeq.Perform(*this, BaseEntity, Kind, Args, nullptr);
if (BaseInit.isInvalid())
  return true;

// C++11 [class.base.init]p7:
//   The initialization of each base and member constitutes a
//   full-expression.
BaseInit = ActOnFinishFullExpr(BaseInit.get(), InitRange.getBegin(),
                               /*DiscardedValue*/ false);
if (BaseInit.isInvalid())
  return true;

// If we are in a dependent context, template instantiation will
// perform this type-checking again. Just save the arguments that we
// received in a ParenListExpr.
// FIXME: This isn't quite ideal, since our ASTs don't capture all
// of the information that we have about the base
// initializer. However, deconstructing the ASTs is a dicey process,
// and this approach is far more likely to get the corner cases right.
if (CurContext->isDependentContext())
  BaseInit = Init;

return new (Context) CXXCtorInitializer(Context, BaseTInfo,
                                        BaseSpec->isVirtual(),
                                        InitRange.getBegin(),
                                        BaseInit.getAs<Expr>(),
                                        InitRange.getEnd(), EllipsisLoc);
4590}

4592// Create a static_cast\<T&&>(expr).
4593static Expr *CastForMoving(Sema &SemaRef, Expr *E, QualType T = QualType()) {
if (T.isNull()) T = E->getType();
QualType TargetType = SemaRef.BuildReferenceType(
    T, /*SpelledAsLValue*/false, SourceLocation(), DeclarationName());
SourceLocation ExprLoc = E->getBeginLoc();
TypeSourceInfo *TargetLoc = SemaRef.Context.getTrivialTypeSourceInfo(
    TargetType, ExprLoc);

return SemaRef.BuildCXXNamedCast(ExprLoc, tok::kw_static_cast, TargetLoc, E,
                                 SourceRange(ExprLoc, ExprLoc),
                                 E->getSourceRange()).get();
4604}

4606/// ImplicitInitializerKind - How an implicit base or member initializer should
4607/// initialize its base or member.
4608enum ImplicitInitializerKind {
IIK_Default,
IIK_Copy,
IIK_Move,
IIK_Inherit
4613};

4615static bool
4616BuildImplicitBaseInitializer(Sema &SemaRef, CXXConstructorDecl *Constructor,
                           ImplicitInitializerKind ImplicitInitKind,
                           CXXBaseSpecifier *BaseSpec,
                           bool IsInheritedVirtualBase,
                           CXXCtorInitializer *&CXXBaseInit) {
InitializedEntity InitEntity
  = InitializedEntity::InitializeBase(SemaRef.Context, BaseSpec,
                                      IsInheritedVirtualBase);

ExprResult BaseInit;

switch (ImplicitInitKind) {
case IIK_Inherit:
case IIK_Default: {
  InitializationKind InitKind
    = InitializationKind::CreateDefault(Constructor->getLocation());
  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, None);
  break;
}

case IIK_Move:
case IIK_Copy: {
  bool Moving = ImplicitInitKind == IIK_Move;
  ParmVarDecl *Param = Constructor->getParamDecl(0);
  QualType ParamType = Param->getType().getNonReferenceType();

  Expr *CopyCtorArg =
    DeclRefExpr::Create(SemaRef.Context, NestedNameSpecifierLoc(),
                        SourceLocation(), Param, false,
                        Constructor->getLocation(), ParamType,
                        VK_LValue, nullptr);

  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(CopyCtorArg));

  // Cast to the base class to avoid ambiguities.
  QualType ArgTy =
    SemaRef.Context.getQualifiedType(BaseSpec->getType().getUnqualifiedType(),
                                     ParamType.getQualifiers());

  if (Moving) {
    CopyCtorArg = CastForMoving(SemaRef, CopyCtorArg);
  }

  CXXCastPath BasePath;
  BasePath.push_back(BaseSpec);
  CopyCtorArg = SemaRef.ImpCastExprToType(CopyCtorArg, ArgTy,
                                          CK_UncheckedDerivedToBase,
                                          Moving ? VK_XValue : VK_LValue,
                                          &BasePath).get();

  InitializationKind InitKind
    = InitializationKind::CreateDirect(Constructor->getLocation(),
                                       SourceLocation(), SourceLocation());
  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, CopyCtorArg);
  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, CopyCtorArg);
  break;
}
}

BaseInit = SemaRef.MaybeCreateExprWithCleanups(BaseInit);
if (BaseInit.isInvalid())
  return true;

CXXBaseInit =
  new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
             SemaRef.Context.getTrivialTypeSourceInfo(BaseSpec->getType(),
                                                      SourceLocation()),
                                           BaseSpec->isVirtual(),
                                           SourceLocation(),
                                           BaseInit.getAs<Expr>(),
                                           SourceLocation(),
                                           SourceLocation());

return false;
4691}

4693static bool RefersToRValueRef(Expr *MemRef) {
ValueDecl *Referenced = cast<MemberExpr>(MemRef)->getMemberDecl();
return Referenced->getType()->isRValueReferenceType();
4696}

4698static bool
4699BuildImplicitMemberInitializer(Sema &SemaRef, CXXConstructorDecl *Constructor,
                             ImplicitInitializerKind ImplicitInitKind,
                             FieldDecl *Field, IndirectFieldDecl *Indirect,
                             CXXCtorInitializer *&CXXMemberInit) {
if (Field->isInvalidDecl())
  return true;

SourceLocation Loc = Constructor->getLocation();

if (ImplicitInitKind == IIK_Copy || ImplicitInitKind == IIK_Move) {
  bool Moving = ImplicitInitKind == IIK_Move;
  ParmVarDecl *Param = Constructor->getParamDecl(0);
  QualType ParamType = Param->getType().getNonReferenceType();

  // Suppress copying zero-width bitfields.
  if (Field->isZeroLengthBitField(SemaRef.Context))
    return false;

  Expr *MemberExprBase =
    DeclRefExpr::Create(SemaRef.Context, NestedNameSpecifierLoc(),
                        SourceLocation(), Param, false,
                        Loc, ParamType, VK_LValue, nullptr);

  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(MemberExprBase));

  if (Moving) {
    MemberExprBase = CastForMoving(SemaRef, MemberExprBase);
  }

  // Build a reference to this field within the parameter.
  CXXScopeSpec SS;
  LookupResult MemberLookup(SemaRef, Field->getDeclName(), Loc,
                            Sema::LookupMemberName);
  MemberLookup.addDecl(Indirect ? cast<ValueDecl>(Indirect)
                                : cast<ValueDecl>(Field), AS_public);
  MemberLookup.resolveKind();
  ExprResult CtorArg
    = SemaRef.BuildMemberReferenceExpr(MemberExprBase,
                                       ParamType, Loc,
                                       /*IsArrow=*/false,
                                       SS,
                                       /*TemplateKWLoc=*/SourceLocation(),
                                       /*FirstQualifierInScope=*/nullptr,
                                       MemberLookup,
                                       /*TemplateArgs=*/nullptr,
                                       /*S*/nullptr);
  if (CtorArg.isInvalid())
    return true;

  // C++11 [class.copy]p15:
  //   - if a member m has rvalue reference type T&&, it is direct-initialized
  //     with static_cast<T&&>(x.m);
  if (RefersToRValueRef(CtorArg.get())) {
    CtorArg = CastForMoving(SemaRef, CtorArg.get());
  }

  InitializedEntity Entity =
      Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
                                                     /*Implicit*/ true)
               : InitializedEntity::InitializeMember(Field, nullptr,
                                                     /*Implicit*/ true);

  // Direct-initialize to use the copy constructor.
  InitializationKind InitKind =
    InitializationKind::CreateDirect(Loc, SourceLocation(), SourceLocation());

  Expr *CtorArgE = CtorArg.getAs<Expr>();
  InitializationSequence InitSeq(SemaRef, Entity, InitKind, CtorArgE);
  ExprResult MemberInit =
      InitSeq.Perform(SemaRef, Entity, InitKind, MultiExprArg(&CtorArgE, 1));
  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
  if (MemberInit.isInvalid())
    return true;

  if (Indirect)
    CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
        SemaRef.Context, Indirect, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
  else
    CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
        SemaRef.Context, Field, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
  return false;
}

assert((ImplicitInitKind == IIK_Default || ImplicitInitKind == IIK_Inherit) &&((void)0)
       "Unhandled implicit init kind!")((void)0);

QualType FieldBaseElementType =
  SemaRef.Context.getBaseElementType(Field->getType());

if (FieldBaseElementType->isRecordType()) {
  InitializedEntity InitEntity =
      Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
                                                     /*Implicit*/ true)
               : InitializedEntity::InitializeMember(Field, nullptr,
                                                     /*Implicit*/ true);
  InitializationKind InitKind =
    InitializationKind::CreateDefault(Loc);

  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
  ExprResult MemberInit =
    InitSeq.Perform(SemaRef, InitEntity, InitKind, None);

  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
  if (MemberInit.isInvalid())
    return true;

  if (Indirect)
    CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
                                                             Indirect, Loc,
                                                             Loc,
                                                             MemberInit.get(),
                                                             Loc);
  else
    CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
                                                             Field, Loc, Loc,
                                                             MemberInit.get(),
                                                             Loc);
  return false;
}

if (!Field->getParent()->isUnion()) {
  if (FieldBaseElementType->isReferenceType()) {
    SemaRef.Diag(Constructor->getLocation(),
                 diag::err_uninitialized_member_in_ctor)
    << (int)Constructor->isImplicit()
    << SemaRef.Context.getTagDeclType(Constructor->getParent())
    << 0 << Field->getDeclName();
    SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
    return true;
  }

  if (FieldBaseElementType.isConstQualified()) {
    SemaRef.Diag(Constructor->getLocation(),
                 diag::err_uninitialized_member_in_ctor)
    << (int)Constructor->isImplicit()
    << SemaRef.Context.getTagDeclType(Constructor->getParent())
    << 1 << Field->getDeclName();
    SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
    return true;
  }
}

if (FieldBaseElementType.hasNonTrivialObjCLifetime()) {
  // ARC and Weak:
  //   Default-initialize Objective-C pointers to NULL.
  CXXMemberInit
    = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context, Field,
                                               Loc, Loc,
               new (SemaRef.Context) ImplicitValueInitExpr(Field->getType()),
                                               Loc);
  return false;
}

// Nothing to initialize.
CXXMemberInit = nullptr;
return false;
4855}

4857namespace {
4858struct BaseAndFieldInfo {
Sema &S;
CXXConstructorDecl *Ctor;
bool AnyErrorsInInits;
ImplicitInitializerKind IIK;
llvm::DenseMap<const void *, CXXCtorInitializer*> AllBaseFields;
SmallVector<CXXCtorInitializer*, 8> AllToInit;
llvm::DenseMap<TagDecl*, FieldDecl*> ActiveUnionMember;

BaseAndFieldInfo(Sema &S, CXXConstructorDecl *Ctor, bool ErrorsInInits)
  : S(S), Ctor(Ctor), AnyErrorsInInits(ErrorsInInits) {
  bool Generated = Ctor->isImplicit() || Ctor->isDefaulted();
  if (Ctor->getInheritedConstructor())
    IIK = IIK_Inherit;
  else if (Generated && Ctor->isCopyConstructor())
    IIK = IIK_Copy;
  else if (Generated && Ctor->isMoveConstructor())
    IIK = IIK_Move;
  else
    IIK = IIK_Default;
}

bool isImplicitCopyOrMove() const {
  switch (IIK) {
  case IIK_Copy:
  case IIK_Move:
    return true;

  case IIK_Default:
  case IIK_Inherit:
    return false;
  }

  llvm_unreachable("Invalid ImplicitInitializerKind!")__builtin_unreachable();
}

bool addFieldInitializer(CXXCtorInitializer *Init) {
  AllToInit.push_back(Init);

  // Check whether this initializer makes the field "used".
  if (Init->getInit()->HasSideEffects(S.Context))
    S.UnusedPrivateFields.remove(Init->getAnyMember());

  return false;
}

bool isInactiveUnionMember(FieldDecl *Field) {
  RecordDecl *Record = Field->getParent();
  if (!Record->isUnion())
    return false;

  if (FieldDecl *Active =
          ActiveUnionMember.lookup(Record->getCanonicalDecl()))
    return Active != Field->getCanonicalDecl();

  // In an implicit copy or move constructor, ignore any in-class initializer.
  if (isImplicitCopyOrMove())
    return true;

  // If there's no explicit initialization, the field is active only if it
  // has an in-class initializer...
  if (Field->hasInClassInitializer())
    return false;
  // ... or it's an anonymous struct or union whose class has an in-class
  // initializer.
  if (!Field->isAnonymousStructOrUnion())
    return true;
  CXXRecordDecl *FieldRD = Field->getType()->getAsCXXRecordDecl();
  return !FieldRD->hasInClassInitializer();
}

/// Determine whether the given field is, or is within, a union member
/// that is inactive (because there was an initializer given for a different
/// member of the union, or because the union was not initialized at all).
bool isWithinInactiveUnionMember(FieldDecl *Field,
                                 IndirectFieldDecl *Indirect) {
  if (!Indirect)
    return isInactiveUnionMember(Field);

  for (auto *C : Indirect->chain()) {
    FieldDecl *Field = dyn_cast<FieldDecl>(C);
    if (Field && isInactiveUnionMember(Field))
      return true;
  }
  return false;
}
4944};
4945}

4947/// Determine whether the given type is an incomplete or zero-lenfgth
4948/// array type.
4949static bool isIncompleteOrZeroLengthArrayType(ASTContext &Context, QualType T) {
if (T->isIncompleteArrayType())
  return true;

while (const ConstantArrayType *ArrayT = Context.getAsConstantArrayType(T)) {
  if (!ArrayT->getSize())
    return true;

  T = ArrayT->getElementType();
}

return false;
4961}

4963static bool CollectFieldInitializer(Sema &SemaRef, BaseAndFieldInfo &Info,
                                  FieldDecl *Field,
                                  IndirectFieldDecl *Indirect = nullptr) {
if (Field->isInvalidDecl())
  return false;

// Overwhelmingly common case: we have a direct initializer for this field.
if (CXXCtorInitializer *Init =
        Info.AllBaseFields.lookup(Field->getCanonicalDecl()))
  return Info.addFieldInitializer(Init);

// C++11 [class.base.init]p8:
//   if the entity is a non-static data member that has a
//   brace-or-equal-initializer and either
//   -- the constructor's class is a union and no other variant member of that
//      union is designated by a mem-initializer-id or
//   -- the constructor's class is not a union, and, if the entity is a member
//      of an anonymous union, no other member of that union is designated by
//      a mem-initializer-id,
//   the entity is initialized as specified in [dcl.init].
//
// We also apply the same rules to handle anonymous structs within anonymous
// unions.
if (Info.isWithinInactiveUnionMember(Field, Indirect))
  return false;

if (Field->hasInClassInitializer() && !Info.isImplicitCopyOrMove()) {
  ExprResult DIE =
      SemaRef.BuildCXXDefaultInitExpr(Info.Ctor->getLocation(), Field);
  if (DIE.isInvalid())
    return true;

  auto Entity = InitializedEntity::InitializeMember(Field, nullptr, true);
  SemaRef.checkInitializerLifetime(Entity, DIE.get());

  CXXCtorInitializer *Init;
  if (Indirect)
    Init = new (SemaRef.Context)
        CXXCtorInitializer(SemaRef.Context, Indirect, SourceLocation(),
                           SourceLocation(), DIE.get(), SourceLocation());
  else
    Init = new (SemaRef.Context)
        CXXCtorInitializer(SemaRef.Context, Field, SourceLocation(),
                           SourceLocation(), DIE.get(), SourceLocation());
  return Info.addFieldInitializer(Init);
}

// Don't initialize incomplete or zero-length arrays.
if (isIncompleteOrZeroLengthArrayType(SemaRef.Context, Field->getType()))
  return false;

// Don't try to build an implicit initializer if there were semantic
// errors in any of the initializers (and therefore we might be
// missing some that the user actually wrote).
if (Info.AnyErrorsInInits)
  return false;

CXXCtorInitializer *Init = nullptr;
if (BuildImplicitMemberInitializer(Info.S, Info.Ctor, Info.IIK, Field,
                                   Indirect, Init))
  return true;

if (!Init)
  return false;

return Info.addFieldInitializer(Init);
5029}

5031bool
5032Sema::SetDelegatingInitializer(CXXConstructorDecl *Constructor,
                             CXXCtorInitializer *Initializer) {
assert(Initializer->isDelegatingInitializer())((void)0);
Constructor->setNumCtorInitializers(1);
CXXCtorInitializer **initializer =
  new (Context) CXXCtorInitializer*[1];
memcpy(initializer, &Initializer, sizeof (CXXCtorInitializer*));
Constructor->setCtorInitializers(initializer);

if (CXXDestructorDecl *Dtor = LookupDestructor(Constructor->getParent())) {
  MarkFunctionReferenced(Initializer->getSourceLocation(), Dtor);
  DiagnoseUseOfDecl(Dtor, Initializer->getSourceLocation());
}

DelegatingCtorDecls.push_back(Constructor);

DiagnoseUninitializedFields(*this, Constructor);

return false;
5051}

5053bool Sema::SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
                             ArrayRef<CXXCtorInitializer *> Initializers) {
if (Constructor->isDependentContext()) {
  // Just store the initializers as written, they will be checked during
  // instantiation.
  if (!Initializers.empty()) {
    Constructor->setNumCtorInitializers(Initializers.size());
    CXXCtorInitializer **baseOrMemberInitializers =
      new (Context) CXXCtorInitializer*[Initializers.size()];
    memcpy(baseOrMemberInitializers, Initializers.data(),
           Initializers.size() * sizeof(CXXCtorInitializer*));
    Constructor->setCtorInitializers(baseOrMemberInitializers);
  }

  // Let template instantiation know whether we had errors.
  if (AnyErrors)
    Constructor->setInvalidDecl();

  return false;
}

BaseAndFieldInfo Info(*this, Constructor, AnyErrors);

// We need to build the initializer AST according to order of construction
// and not what user specified in the Initializers list.
CXXRecordDecl *ClassDecl = Constructor->getParent()->getDefinition();
if (!ClassDecl)
  return true;

bool HadError = false;

for (unsigned i = 0; i < Initializers.size(); i++) {
  CXXCtorInitializer *Member = Initializers[i];

  if (Member->isBaseInitializer())
    Info.AllBaseFields[Member->getBaseClass()->getAs<RecordType>()] = Member;
  else {
    Info.AllBaseFields[Member->getAnyMember()->getCanonicalDecl()] = Member;

    if (IndirectFieldDecl *F = Member->getIndirectMember()) {
      for (auto *C : F->chain()) {
        FieldDecl *FD = dyn_cast<FieldDecl>(C);
        if (FD && FD->getParent()->isUnion())
          Info.ActiveUnionMember.insert(std::make_pair(
              FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
      }
    } else if (FieldDecl *FD = Member->getMember()) {
      if (FD->getParent()->isUnion())
        Info.ActiveUnionMember.insert(std::make_pair(
            FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
    }
  }
}

// Keep track of the direct virtual bases.
llvm::SmallPtrSet<CXXBaseSpecifier *, 16> DirectVBases;
for (auto &I : ClassDecl->bases()) {
  if (I.isVirtual())
    DirectVBases.insert(&I);
}

// Push virtual bases before others.
for (auto &VBase : ClassDecl->vbases()) {
  if (CXXCtorInitializer *Value
      = Info.AllBaseFields.lookup(VBase.getType()->getAs<RecordType>())) {
    // [class.base.init]p7, per DR257:
    //   A mem-initializer where the mem-initializer-id names a virtual base
    //   class is ignored during execution of a constructor of any class that
    //   is not the most derived class.
    if (ClassDecl->isAbstract()) {
      // FIXME: Provide a fixit to remove the base specifier. This requires
      // tracking the location of the associated comma for a base specifier.
      Diag(Value->getSourceLocation(), diag::warn_abstract_vbase_init_ignored)
        << VBase.getType() << ClassDecl;
      DiagnoseAbstractType(ClassDecl);
    }

    Info.AllToInit.push_back(Value);
  } else if (!AnyErrors && !ClassDecl->isAbstract()) {
    // [class.base.init]p8, per DR257:
    //   If a given [...] base class is not named by a mem-initializer-id
    //   [...] and the entity is not a virtual base class of an abstract
    //   class, then [...] the entity is default-initialized.
    bool IsInheritedVirtualBase = !DirectVBases.count(&VBase);
    CXXCtorInitializer *CXXBaseInit;
    if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
                                     &VBase, IsInheritedVirtualBase,
                                     CXXBaseInit)) {
      HadError = true;
      continue;
    }

    Info.AllToInit.push_back(CXXBaseInit);
  }
}

// Non-virtual bases.
for (auto &Base : ClassDecl->bases()) {
  // Virtuals are in the virtual base list and already constructed.
  if (Base.isVirtual())
    continue;

  if (CXXCtorInitializer *Value
        = Info.AllBaseFields.lookup(Base.getType()->getAs<RecordType>())) {
    Info.AllToInit.push_back(Value);
  } else if (!AnyErrors) {
    CXXCtorInitializer *CXXBaseInit;
    if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
                                     &Base, /*IsInheritedVirtualBase=*/false,
                                     CXXBaseInit)) {
      HadError = true;
      continue;
    }

    Info.AllToInit.push_back(CXXBaseInit);
  }
}

// Fields.
for (auto *Mem : ClassDecl->decls()) {
  if (auto *F = dyn_cast<FieldDecl>(Mem)) {
    // C++ [class.bit]p2:
    //   A declaration for a bit-field that omits the identifier declares an
    //   unnamed bit-field. Unnamed bit-fields are not members and cannot be
    //   initialized.
    if (F->isUnnamedBitfield())
      continue;

    // If we're not generating the implicit copy/move constructor, then we'll
    // handle anonymous struct/union fields based on their individual
    // indirect fields.
    if (F->isAnonymousStructOrUnion() && !Info.isImplicitCopyOrMove())
      continue;

    if (CollectFieldInitializer(*this, Info, F))
      HadError = true;
    continue;
  }

  // Beyond this point, we only consider default initialization.
  if (Info.isImplicitCopyOrMove())
    continue;

  if (auto *F = dyn_cast<IndirectFieldDecl>(Mem)) {
    if (F->getType()->isIncompleteArrayType()) {
      assert(ClassDecl->hasFlexibleArrayMember() &&((void)0)
             "Incomplete array type is not valid")((void)0);
      continue;
    }

    // Initialize each field of an anonymous struct individually.
    if (CollectFieldInitializer(*this, Info, F->getAnonField(), F))
      HadError = true;

    continue;
  }
}

unsigned NumInitializers = Info.AllToInit.size();
if (NumInitializers > 0) {
  Constructor->setNumCtorInitializers(NumInitializers);
  CXXCtorInitializer **baseOrMemberInitializers =
    new (Context) CXXCtorInitializer*[NumInitializers];
  memcpy(baseOrMemberInitializers, Info.AllToInit.data(),
         NumInitializers * sizeof(CXXCtorInitializer*));
  Constructor->setCtorInitializers(baseOrMemberInitializers);

  // Constructors implicitly reference the base and member
  // destructors.
  MarkBaseAndMemberDestructorsReferenced(Constructor->getLocation(),
                                         Constructor->getParent());
}

return HadError;
5227}

5229static void PopulateKeysForFields(FieldDecl *Field, SmallVectorImpl<const void*> &IdealInits) {
if (const RecordType *RT = Field->getType()->getAs<RecordType>()) {
  const RecordDecl *RD = RT->getDecl();
  if (RD->isAnonymousStructOrUnion()) {
    for (auto *Field : RD->fields())
      PopulateKeysForFields(Field, IdealInits);
    return;
  }
}
IdealInits.push_back(Field->getCanonicalDecl());
5239}

5241static const void *GetKeyForBase(ASTContext &Context, QualType BaseType) {
return Context.getCanonicalType(BaseType).getTypePtr();
5243}

5245static const void *GetKeyForMember(ASTContext &Context,
                                 CXXCtorInitializer *Member) {
if (!Member->isAnyMemberInitializer())
  return GetKeyForBase(Context, QualType(Member->getBaseClass(), 0));

return Member->getAnyMember()->getCanonicalDecl();
5251}

5253static void AddInitializerToDiag(const Sema::SemaDiagnosticBuilder &Diag,
                               const CXXCtorInitializer *Previous,
                               const CXXCtorInitializer *Current) {
if (Previous->isAnyMemberInitializer())
  Diag << 0 << Previous->getAnyMember();
else
  Diag << 1 << Previous->getTypeSourceInfo()->getType();

if (Current->isAnyMemberInitializer())
  Diag << 0 << Current->getAnyMember();
else
  Diag << 1 << Current->getTypeSourceInfo()->getType();
5265}

5267static void DiagnoseBaseOrMemInitializerOrder(
  Sema &SemaRef, const CXXConstructorDecl *Constructor,
  ArrayRef<CXXCtorInitializer *> Inits) {
if (Constructor->getDeclContext()->isDependentContext())
  return;

// Don't check initializers order unless the warning is enabled at the
// location of at least one initializer.
bool ShouldCheckOrder = false;
for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
  CXXCtorInitializer *Init = Inits[InitIndex];
  if (!SemaRef.Diags.isIgnored(diag::warn_initializer_out_of_order,
                               Init->getSourceLocation())) {
    ShouldCheckOrder = true;
    break;
  }
}
if (!ShouldCheckOrder)
  return;

// Build the list of bases and members in the order that they'll
// actually be initialized.  The explicit initializers should be in
// this same order but may be missing things.
SmallVector<const void*, 32> IdealInitKeys;

const CXXRecordDecl *ClassDecl = Constructor->getParent();

// 1. Virtual bases.
for (const auto &VBase : ClassDecl->vbases())
  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, VBase.getType()));

// 2. Non-virtual bases.
for (const auto &Base : ClassDecl->bases()) {
  if (Base.isVirtual())
    continue;
  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, Base.getType()));
}

// 3. Direct fields.
for (auto *Field : ClassDecl->fields()) {
  if (Field->isUnnamedBitfield())
    continue;

  PopulateKeysForFields(Field, IdealInitKeys);
}

unsigned NumIdealInits = IdealInitKeys.size();
unsigned IdealIndex = 0;

// Track initializers that are in an incorrect order for either a warning or
// note if multiple ones occur.
SmallVector<unsigned> WarnIndexes;
// Correlates the index of an initializer in the init-list to the index of
// the field/base in the class.
SmallVector<std::pair<unsigned, unsigned>, 32> CorrelatedInitOrder;

for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
  const void *InitKey = GetKeyForMember(SemaRef.Context, Inits[InitIndex]);

  // Scan forward to try to find this initializer in the idealized
  // initializers list.
  for (; IdealIndex != NumIdealInits; ++IdealIndex)
    if (InitKey == IdealInitKeys[IdealIndex])
      break;

  // If we didn't find this initializer, it must be because we
  // scanned past it on a previous iteration.  That can only
  // happen if we're out of order;  emit a warning.
  if (IdealIndex == NumIdealInits && InitIndex) {
    WarnIndexes.push_back(InitIndex);

    // Move back to the initializer's location in the ideal list.
    for (IdealIndex = 0; IdealIndex != NumIdealInits; ++IdealIndex)
      if (InitKey == IdealInitKeys[IdealIndex])
        break;

    assert(IdealIndex < NumIdealInits &&((void)0)
           "initializer not found in initializer list")((void)0);
  }
  CorrelatedInitOrder.emplace_back(IdealIndex, InitIndex);
}

if (WarnIndexes.empty())
  return;

// Sort based on the ideal order, first in the pair.
llvm::sort(CorrelatedInitOrder,
           [](auto &LHS, auto &RHS) { return LHS.first < RHS.first; });

// Introduce a new scope as SemaDiagnosticBuilder needs to be destroyed to
// emit the diagnostic before we can try adding notes.
{
  Sema::SemaDiagnosticBuilder D = SemaRef.Diag(
      Inits[WarnIndexes.front() - 1]->getSourceLocation(),
      WarnIndexes.size() == 1 ? diag::warn_initializer_out_of_order
                              : diag::warn_some_initializers_out_of_order);

  for (unsigned I = 0; I < CorrelatedInitOrder.size(); ++I) {
    if (CorrelatedInitOrder[I].second == I)
      continue;
    // Ideally we would be using InsertFromRange here, but clang doesn't
    // appear to handle InsertFromRange correctly when the source range is
    // modified by another fix-it.
    D << FixItHint::CreateReplacement(
        Inits[I]->getSourceRange(),
        Lexer::getSourceText(
            CharSourceRange::getTokenRange(
                Inits[CorrelatedInitOrder[I].second]->getSourceRange()),
            SemaRef.getSourceManager(), SemaRef.getLangOpts()));
  }

  // If there is only 1 item out of order, the warning expects the name and
  // type of each being added to it.
  if (WarnIndexes.size() == 1) {
    AddInitializerToDiag(D, Inits[WarnIndexes.front() - 1],
                         Inits[WarnIndexes.front()]);
    return;
  }
}
// More than 1 item to warn, create notes letting the user know which ones
// are bad.
for (unsigned WarnIndex : WarnIndexes) {
  const clang::CXXCtorInitializer *PrevInit = Inits[WarnIndex - 1];
  auto D = SemaRef.Diag(PrevInit->getSourceLocation(),
                        diag::note_initializer_out_of_order);
  AddInitializerToDiag(D, PrevInit, Inits[WarnIndex]);
  D << PrevInit->getSourceRange();
}
5395}

5397namespace {
5398bool CheckRedundantInit(Sema &S,
                      CXXCtorInitializer *Init,
                      CXXCtorInitializer *&PrevInit) {
if (!PrevInit) {
  PrevInit = Init;
  return false;
}

if (FieldDecl *Field = Init->getAnyMember())
  S.Diag(Init->getSourceLocation(),
         diag::err_multiple_mem_initialization)
    << Field->getDeclName()
    << Init->getSourceRange();
else {
  const Type *BaseClass = Init->getBaseClass();
  assert(BaseClass && "neither field nor base")((void)0);
  S.Diag(Init->getSourceLocation(),
         diag::err_multiple_base_initialization)
    << QualType(BaseClass, 0)
    << Init->getSourceRange();
}
S.Diag(PrevInit->getSourceLocation(), diag::note_previous_initializer)
  << 0 << PrevInit->getSourceRange();

return true;
5423}

5425typedef std::pair<NamedDecl *, CXXCtorInitializer *> UnionEntry;
5426typedef llvm::DenseMap<RecordDecl*, UnionEntry> RedundantUnionMap;

5428bool CheckRedundantUnionInit(Sema &S,
                           CXXCtorInitializer *Init,
                           RedundantUnionMap &Unions) {
FieldDecl *Field = Init->getAnyMember();
RecordDecl *Parent = Field->getParent();
NamedDecl *Child = Field;

while (Parent->isAnonymousStructOrUnion() || Parent->isUnion()) {
  if (Parent->isUnion()) {
    UnionEntry &En = Unions[Parent];
    if (En.first && En.first != Child) {
      S.Diag(Init->getSourceLocation(),
             diag::err_multiple_mem_union_initialization)
        << Field->getDeclName()
        << Init->getSourceRange();
      S.Diag(En.second->getSourceLocation(), diag::note_previous_initializer)
        << 0 << En.second->getSourceRange();
      return true;
    }
    if (!En.first) {
      En.first = Child;
      En.second = Init;
    }
    if (!Parent->isAnonymousStructOrUnion())
      return false;
  }

  Child = Parent;
  Parent = cast<RecordDecl>(Parent->getDeclContext());
}

return false;
5460}
5461} // namespace

5463/// ActOnMemInitializers - Handle the member initializers for a constructor.
5464void Sema::ActOnMemInitializers(Decl *ConstructorDecl,
                              SourceLocation ColonLoc,
                              ArrayRef<CXXCtorInitializer*> MemInits,
                              bool AnyErrors) {
if (!ConstructorDecl)
  return;

AdjustDeclIfTemplate(ConstructorDecl);

CXXConstructorDecl *Constructor
  = dyn_cast<CXXConstructorDecl>(ConstructorDecl);

if (!Constructor) {
  Diag(ColonLoc, diag::err_only_constructors_take_base_inits);
  return;
}

// Mapping for the duplicate initializers check.
// For member initializers, this is keyed with a FieldDecl*.
// For base initializers, this is keyed with a Type*.
llvm::DenseMap<const void *, CXXCtorInitializer *> Members;

// Mapping for the inconsistent anonymous-union initializers check.
RedundantUnionMap MemberUnions;

bool HadError = false;
for (unsigned i = 0; i < MemInits.size(); i++) {
  CXXCtorInitializer *Init = MemInits[i];

  // Set the source order index.
  Init->setSourceOrder(i);

  if (Init->isAnyMemberInitializer()) {
    const void *Key = GetKeyForMember(Context, Init);
    if (CheckRedundantInit(*this, Init, Members[Key]) ||
        CheckRedundantUnionInit(*this, Init, MemberUnions))
      HadError = true;
  } else if (Init->isBaseInitializer()) {
    const void *Key = GetKeyForMember(Context, Init);
    if (CheckRedundantInit(*this, Init, Members[Key]))
      HadError = true;
  } else {
    assert(Init->isDelegatingInitializer())((void)0);
    // This must be the only initializer
    if (MemInits.size() != 1) {
      Diag(Init->getSourceLocation(),
           diag::err_delegating_initializer_alone)
        << Init->getSourceRange() << MemInits[i ? 0 : 1]->getSourceRange();
      // We will treat this as being the only initializer.
    }
    SetDelegatingInitializer(Constructor, MemInits[i]);
    // Return immediately as the initializer is set.
    return;
  }
}

if (HadError)
  return;

DiagnoseBaseOrMemInitializerOrder(*this, Constructor, MemInits);

SetCtorInitializers(Constructor, AnyErrors, MemInits);

DiagnoseUninitializedFields(*this, Constructor);
5528}

5530void
5531Sema::MarkBaseAndMemberDestructorsReferenced(SourceLocation Location,
                                           CXXRecordDecl *ClassDecl) {
// Ignore dependent contexts. Also ignore unions, since their members never
// have destructors implicitly called.
if (ClassDecl->isDependentContext() || ClassDecl->isUnion())
  return;

// FIXME: all the access-control diagnostics are positioned on the
// field/base declaration.  That's probably good; that said, the
// user might reasonably want to know why the destructor is being
// emitted, and we currently don't say.

// Non-static data members.
for (auto *Field : ClassDecl->fields()) {
  if (Field->isInvalidDecl())
    continue;

  // Don't destroy incomplete or zero-length arrays.
  if (isIncompleteOrZeroLengthArrayType(Context, Field->getType()))
    continue;

  QualType FieldType = Context.getBaseElementType(Field->getType());

  const RecordType* RT = FieldType->getAs<RecordType>();
  if (!RT)
    continue;

  CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
  if (FieldClassDecl->isInvalidDecl())
    continue;
  if (FieldClassDecl->hasIrrelevantDestructor())
    continue;
  // The destructor for an implicit anonymous union member is never invoked.
  if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
    continue;

  CXXDestructorDecl *Dtor = LookupDestructor(FieldClassDecl);
  assert(Dtor && "No dtor found for FieldClassDecl!")((void)0);
  CheckDestructorAccess(Field->getLocation(), Dtor,
                        PDiag(diag::err_access_dtor_field)
                          << Field->getDeclName()
                          << FieldType);

  MarkFunctionReferenced(Location, Dtor);
  DiagnoseUseOfDecl(Dtor, Location);
}

// We only potentially invoke the destructors of potentially constructed
// subobjects.
bool VisitVirtualBases = !ClassDecl->isAbstract();

// If the destructor exists and has already been marked used in the MS ABI,
// then virtual base destructors have already been checked and marked used.
// Skip checking them again to avoid duplicate diagnostics.
if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
  CXXDestructorDecl *Dtor = ClassDecl->getDestructor();
  if (Dtor && Dtor->isUsed())
    VisitVirtualBases = false;
}

llvm::SmallPtrSet<const RecordType *, 8> DirectVirtualBases;

// Bases.
for (const auto &Base : ClassDecl->bases()) {
  const RecordType *RT = Base.getType()->getAs<RecordType>();
  if (!RT)
    continue;

  // Remember direct virtual bases.
  if (Base.isVirtual()) {
    if (!VisitVirtualBases)
      continue;
    DirectVirtualBases.insert(RT);
  }

  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
  // If our base class is invalid, we probably can't get its dtor anyway.
  if (BaseClassDecl->isInvalidDecl())
    continue;
  if (BaseClassDecl->hasIrrelevantDestructor())
    continue;

  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
  assert(Dtor && "No dtor found for BaseClassDecl!")((void)0);

  // FIXME: caret should be on the start of the class name
  CheckDestructorAccess(Base.getBeginLoc(), Dtor,
                        PDiag(diag::err_access_dtor_base)
                            << Base.getType() << Base.getSourceRange(),
                        Context.getTypeDeclType(ClassDecl));

  MarkFunctionReferenced(Location, Dtor);
  DiagnoseUseOfDecl(Dtor, Location);
}

if (VisitVirtualBases)
  MarkVirtualBaseDestructorsReferenced(Location, ClassDecl,
                                       &DirectVirtualBases);
5629}

5631void Sema::MarkVirtualBaseDestructorsReferenced(
  SourceLocation Location, CXXRecordDecl *ClassDecl,
  llvm::SmallPtrSetImpl<const RecordType *> *DirectVirtualBases) {
// Virtual bases.
for (const auto &VBase : ClassDecl->vbases()) {
  // Bases are always records in a well-formed non-dependent class.
  const RecordType *RT = VBase.getType()->castAs<RecordType>();

  // Ignore already visited direct virtual bases.
  if (DirectVirtualBases && DirectVirtualBases->count(RT))
    continue;

  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
  // If our base class is invalid, we probably can't get its dtor anyway.
  if (BaseClassDecl->isInvalidDecl())
    continue;
  if (BaseClassDecl->hasIrrelevantDestructor())
    continue;

  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
  assert(Dtor && "No dtor found for BaseClassDecl!")((void)0);
  if (CheckDestructorAccess(
          ClassDecl->getLocation(), Dtor,
          PDiag(diag::err_access_dtor_vbase)
              << Context.getTypeDeclType(ClassDecl) << VBase.getType(),
          Context.getTypeDeclType(ClassDecl)) ==
      AR_accessible) {
    CheckDerivedToBaseConversion(
        Context.getTypeDeclType(ClassDecl), VBase.getType(),
        diag::err_access_dtor_vbase, 0, ClassDecl->getLocation(),
        SourceRange(), DeclarationName(), nullptr);
  }

  MarkFunctionReferenced(Location, Dtor);
  DiagnoseUseOfDecl(Dtor, Location);
}
5667}

5669void Sema::ActOnDefaultCtorInitializers(Decl *CDtorDecl) {
if (!CDtorDecl)
  return;

if (CXXConstructorDecl *Constructor
    = dyn_cast<CXXConstructorDecl>(CDtorDecl)) {
  SetCtorInitializers(Constructor, /*AnyErrors=*/false);
  DiagnoseUninitializedFields(*this, Constructor);
}
5678}

5680bool Sema::isAbstractType(SourceLocation Loc, QualType T) {
if (!getLangOpts().CPlusPlus)
  return false;

const auto *RD = Context.getBaseElementType(T)->getAsCXXRecordDecl();
if (!RD)
  return false;

// FIXME: Per [temp.inst]p1, we are supposed to trigger instantiation of a
// class template specialization here, but doing so breaks a lot of code.

// We can't answer whether something is abstract until it has a
// definition. If it's currently being defined, we'll walk back
// over all the declarations when we have a full definition.
const CXXRecordDecl *Def = RD->getDefinition();
if (!Def || Def->isBeingDefined())
  return false;

return RD->isAbstract();
5699}

5701bool Sema::RequireNonAbstractType(SourceLocation Loc, QualType T,
                                TypeDiagnoser &Diagnoser) {
if (!isAbstractType(Loc, T))
  return false;

T = Context.getBaseElementType(T);
Diagnoser.diagnose(*this, Loc, T);
DiagnoseAbstractType(T->getAsCXXRecordDecl());
return true;
5710}

5712void Sema::DiagnoseAbstractType(const CXXRecordDecl *RD) {
// Check if we've already emitted the list of pure virtual functions
// for this class.
if (PureVirtualClassDiagSet && PureVirtualClassDiagSet->count(RD))
  return;

// If the diagnostic is suppressed, don't emit the notes. We're only
// going to emit them once, so try to attach them to a diagnostic we're
// actually going to show.
if (Diags.isLastDiagnosticIgnored())
  return;

CXXFinalOverriderMap FinalOverriders;
RD->getFinalOverriders(FinalOverriders);

// Keep a set of seen pure methods so we won't diagnose the same method
// more than once.
llvm::SmallPtrSet<const CXXMethodDecl *, 8> SeenPureMethods;

for (CXXFinalOverriderMap::iterator M = FinalOverriders.begin(),
                                 MEnd = FinalOverriders.end();
     M != MEnd;
     ++M) {
  for (OverridingMethods::iterator SO = M->second.begin(),
                                SOEnd = M->second.end();
       SO != SOEnd; ++SO) {
    // C++ [class.abstract]p4:
    //   A class is abstract if it contains or inherits at least one
    //   pure virtual function for which the final overrider is pure
    //   virtual.

    //
    if (SO->second.size() != 1)
      continue;

    if (!SO->second.front().Method->isPure())
      continue;

    if (!SeenPureMethods.insert(SO->second.front().Method).second)
      continue;

    Diag(SO->second.front().Method->getLocation(),
         diag::note_pure_virtual_function)
      << SO->second.front().Method->getDeclName() << RD->getDeclName();
  }
}

if (!PureVirtualClassDiagSet)
  PureVirtualClassDiagSet.reset(new RecordDeclSetTy);
PureVirtualClassDiagSet->insert(RD);
5762}

5764namespace {
5765struct AbstractUsageInfo {
Sema &S;
CXXRecordDecl *Record;
CanQualType AbstractType;
bool Invalid;

AbstractUsageInfo(Sema &S, CXXRecordDecl *Record)
  : S(S), Record(Record),
    AbstractType(S.Context.getCanonicalType(
                 S.Context.getTypeDeclType(Record))),
    Invalid(false) {}

void DiagnoseAbstractType() {
  if (Invalid) return;
  S.DiagnoseAbstractType(Record);
  Invalid = true;
}

void CheckType(const NamedDecl *D, TypeLoc TL, Sema::AbstractDiagSelID Sel);
5784};

5786struct CheckAbstractUsage {
AbstractUsageInfo &Info;
const NamedDecl *Ctx;

CheckAbstractUsage(AbstractUsageInfo &Info, const NamedDecl *Ctx)
  : Info(Info), Ctx(Ctx) {}

void Visit(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
  switch (TL.getTypeLocClass()) {
5795#define ABSTRACT_TYPELOC(CLASS, PARENT)
5796#define TYPELOC(CLASS, PARENT) \
  case TypeLoc::CLASS: Check(TL.castAs<CLASS##TypeLoc>(), Sel); break;
5798#include "clang/AST/TypeLocNodes.def"
  }
}

void Check(FunctionProtoTypeLoc TL, Sema::AbstractDiagSelID Sel) {
  Visit(TL.getReturnLoc(), Sema::AbstractReturnType);
  for (unsigned I = 0, E = TL.getNumParams(); I != E; ++I) {
    if (!TL.getParam(I))
      continue;

    TypeSourceInfo *TSI = TL.getParam(I)->getTypeSourceInfo();
    if (TSI) Visit(TSI->getTypeLoc(), Sema::AbstractParamType);
  }
}

void Check(ArrayTypeLoc TL, Sema::AbstractDiagSelID Sel) {
  Visit(TL.getElementLoc(), Sema::AbstractArrayType);
}

void Check(TemplateSpecializationTypeLoc TL, Sema::AbstractDiagSelID Sel) {
  // Visit the type parameters from a permissive context.
  for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I) {
    TemplateArgumentLoc TAL = TL.getArgLoc(I);
    if (TAL.getArgument().getKind() == TemplateArgument::Type)
      if (TypeSourceInfo *TSI = TAL.getTypeSourceInfo())
        Visit(TSI->getTypeLoc(), Sema::AbstractNone);
    // TODO: other template argument types?
  }
}

// Visit pointee types from a permissive context.
5829#define CheckPolymorphic(Type)void Check(Type TL, Sema::AbstractDiagSelID Sel) { Visit(TL.getNextTypeLoc
(), Sema::AbstractNone); } \
void Check(Type TL, Sema::AbstractDiagSelID Sel) { \
  Visit(TL.getNextTypeLoc(), Sema::AbstractNone); \
}
CheckPolymorphic(PointerTypeLoc)void Check(PointerTypeLoc TL, Sema::AbstractDiagSelID Sel) { Visit
(TL.getNextTypeLoc(), Sema::AbstractNone); }
CheckPolymorphic(ReferenceTypeLoc)void Check(ReferenceTypeLoc TL, Sema::AbstractDiagSelID Sel) {
 Visit(TL.getNextTypeLoc(), Sema::AbstractNone); }
CheckPolymorphic(MemberPointerTypeLoc)void Check(MemberPointerTypeLoc TL, Sema::AbstractDiagSelID Sel
) { Visit(TL.getNextTypeLoc(), Sema::AbstractNone); }
CheckPolymorphic(BlockPointerTypeLoc)void Check(BlockPointerTypeLoc TL, Sema::AbstractDiagSelID Sel
) { Visit(TL.getNextTypeLoc(), Sema::AbstractNone); }
CheckPolymorphic(AtomicTypeLoc)void Check(AtomicTypeLoc TL, Sema::AbstractDiagSelID Sel) { Visit
(TL.getNextTypeLoc(), Sema::AbstractNone); }

/// Handle all the types we haven't given a more specific
/// implementation for above.
void Check(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
  // Every other kind of type that we haven't called out already
  // that has an inner type is either (1) sugar or (2) contains that
  // inner type in some way as a subobject.
  if (TypeLoc Next = TL.getNextTypeLoc())
    return Visit(Next, Sel);

  // If there's no inner type and we're in a permissive context,
  // don't diagnose.
  if (Sel == Sema::AbstractNone) return;

  // Check whether the type matches the abstract type.
  QualType T = TL.getType();
  if (T->isArrayType()) {
    Sel = Sema::AbstractArrayType;
    T = Info.S.Context.getBaseElementType(T);
  }
  CanQualType CT = T->getCanonicalTypeUnqualified().getUnqualifiedType();
  if (CT != Info.AbstractType) return;

  // It matched; do some magic.
  if (Sel == Sema::AbstractArrayType) {
    Info.S.Diag(Ctx->getLocation(), diag::err_array_of_abstract_type)
      << T << TL.getSourceRange();
  } else {
    Info.S.Diag(Ctx->getLocation(), diag::err_abstract_type_in_decl)
      << Sel << T << TL.getSourceRange();
  }
  Info.DiagnoseAbstractType();
}
5871};

5873void AbstractUsageInfo::CheckType(const NamedDecl *D, TypeLoc TL,
                                Sema::AbstractDiagSelID Sel) {
CheckAbstractUsage(*this, D).Visit(TL, Sel);
5876}

5878}

5880/// Check for invalid uses of an abstract type in a method declaration.
5881static void CheckAbstractClassUsage(AbstractUsageInfo &Info,
                                  CXXMethodDecl *MD) {
// No need to do the check on definitions, which require that
// the return/param types be complete.
if (MD->doesThisDeclarationHaveABody())
  return;

// For safety's sake, just ignore it if we don't have type source
// information.  This should never happen for non-implicit methods,
// but...
if (TypeSourceInfo *TSI = MD->getTypeSourceInfo())
  Info.CheckType(MD, TSI->getTypeLoc(), Sema::AbstractNone);
5893}

5895/// Check for invalid uses of an abstract type within a class definition.
5896static void CheckAbstractClassUsage(AbstractUsageInfo &Info,
                                  CXXRecordDecl *RD) {
for (auto *D : RD->decls()) {
  if (D->isImplicit()) continue;

  // Methods and method templates.
  if (isa<CXXMethodDecl>(D)) {
    CheckAbstractClassUsage(Info, cast<CXXMethodDecl>(D));
  } else if (isa<FunctionTemplateDecl>(D)) {
    FunctionDecl *FD = cast<FunctionTemplateDecl>(D)->getTemplatedDecl();
    CheckAbstractClassUsage(Info, cast<CXXMethodDecl>(FD));

  // Fields and static variables.
  } else if (isa<FieldDecl>(D)) {
    FieldDecl *FD = cast<FieldDecl>(D);
    if (TypeSourceInfo *TSI = FD->getTypeSourceInfo())
      Info.CheckType(FD, TSI->getTypeLoc(), Sema::AbstractFieldType);
  } else if (isa<VarDecl>(D)) {
    VarDecl *VD = cast<VarDecl>(D);
    if (TypeSourceInfo *TSI = VD->getTypeSourceInfo())
      Info.CheckType(VD, TSI->getTypeLoc(), Sema::AbstractVariableType);

  // Nested classes and class templates.
  } else if (isa<CXXRecordDecl>(D)) {
    CheckAbstractClassUsage(Info, cast<CXXRecordDecl>(D));
  } else if (isa<ClassTemplateDecl>(D)) {
    CheckAbstractClassUsage(Info,
                           cast<ClassTemplateDecl>(D)->getTemplatedDecl());
  }
}
5926}

5928static void ReferenceDllExportedMembers(Sema &S, CXXRecordDecl *Class) {
Attr *ClassAttr = getDLLAttr(Class);
if (!ClassAttr)
  return;

assert(ClassAttr->getKind() == attr::DLLExport)((void)0);

TemplateSpecializationKind TSK = Class->getTemplateSpecializationKind();

if (TSK == TSK_ExplicitInstantiationDeclaration)
  // Don't go any further if this is just an explicit instantiation
  // declaration.
  return;

// Add a context note to explain how we got to any diagnostics produced below.
struct MarkingClassDllexported {
  Sema &S;
  MarkingClassDllexported(Sema &S, CXXRecordDecl *Class,
                          SourceLocation AttrLoc)
      : S(S) {
    Sema::CodeSynthesisContext Ctx;
    Ctx.Kind = Sema::CodeSynthesisContext::MarkingClassDllexported;
    Ctx.PointOfInstantiation = AttrLoc;
    Ctx.Entity = Class;
    S.pushCodeSynthesisContext(Ctx);
  }
  ~MarkingClassDllexported() {
    S.popCodeSynthesisContext();
  }
} MarkingDllexportedContext(S, Class, ClassAttr->getLocation());

if (S.Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
  S.MarkVTableUsed(Class->getLocation(), Class, true);

for (Decl *Member : Class->decls()) {
  // Defined static variables that are members of an exported base
  // class must be marked export too.
  auto *VD = dyn_cast<VarDecl>(Member);
  if (VD && Member->getAttr<DLLExportAttr>() &&
      VD->getStorageClass() == SC_Static &&
      TSK == TSK_ImplicitInstantiation)
    S.MarkVariableReferenced(VD->getLocation(), VD);

  auto *MD = dyn_cast<CXXMethodDecl>(Member);
  if (!MD)
    continue;

  if (Member->getAttr<DLLExportAttr>()) {
    if (MD->isUserProvided()) {
      // Instantiate non-default class member functions ...

      // .. except for certain kinds of template specializations.
      if (TSK == TSK_ImplicitInstantiation && !ClassAttr->isInherited())
        continue;

      S.MarkFunctionReferenced(Class->getLocation(), MD);

      // The function will be passed to the consumer when its definition is
      // encountered.
    } else if (MD->isExplicitlyDefaulted()) {
      // Synthesize and instantiate explicitly defaulted methods.
      S.MarkFunctionReferenced(Class->getLocation(), MD);

      if (TSK != TSK_ExplicitInstantiationDefinition) {
        // Except for explicit instantiation defs, we will not see the
        // definition again later, so pass it to the consumer now.
        S.Consumer.HandleTopLevelDecl(DeclGroupRef(MD));
      }
    } else if (!MD->isTrivial() ||
               MD->isCopyAssignmentOperator() ||
               MD->isMoveAssignmentOperator()) {
      // Synthesize and instantiate non-trivial implicit methods, and the copy
      // and move assignment operators. The latter are exported even if they
      // are trivial, because the address of an operator can be taken and
      // should compare equal across libraries.
      S.MarkFunctionReferenced(Class->getLocation(), MD);

      // There is no later point when we will see the definition of this
      // function, so pass it to the consumer now.
      S.Consumer.HandleTopLevelDecl(DeclGroupRef(MD));
    }
  }
}
6011}

6013static void checkForMultipleExportedDefaultConstructors(Sema &S,
                                                      CXXRecordDecl *Class) {
// Only the MS ABI has default constructor closures, so we don't need to do
// this semantic checking anywhere else.
if (!S.Context.getTargetInfo().getCXXABI().isMicrosoft())
  return;

CXXConstructorDecl *LastExportedDefaultCtor = nullptr;
for (Decl *Member : Class->decls()) {
  // Look for exported default constructors.
  auto *CD = dyn_cast<CXXConstructorDecl>(Member);
  if (!CD || !CD->isDefaultConstructor())
    continue;
  auto *Attr = CD->getAttr<DLLExportAttr>();
  if (!Attr)
    continue;

  // If the class is non-dependent, mark the default arguments as ODR-used so
  // that we can properly codegen the constructor closure.
  if (!Class->isDependentContext()) {
    for (ParmVarDecl *PD : CD->parameters()) {
      (void)S.CheckCXXDefaultArgExpr(Attr->getLocation(), CD, PD);
      S.DiscardCleanupsInEvaluationContext();
    }
  }

  if (LastExportedDefaultCtor) {
    S.Diag(LastExportedDefaultCtor->getLocation(),
           diag::err_attribute_dll_ambiguous_default_ctor)
        << Class;
    S.Diag(CD->getLocation(), diag::note_entity_declared_at)
        << CD->getDeclName();
    return;
  }
  LastExportedDefaultCtor = CD;
}
6049}

6051static void checkCUDADeviceBuiltinSurfaceClassTemplate(Sema &S,
                                                     CXXRecordDecl *Class) {
bool ErrorReported = false;
auto reportIllegalClassTemplate = [&ErrorReported](Sema &S,
                                                   ClassTemplateDecl *TD) {
  if (ErrorReported)
    return;
  S.Diag(TD->getLocation(),
         diag::err_cuda_device_builtin_surftex_cls_template)
      << /*surface*/ 0 << TD;
  ErrorReported = true;
};

ClassTemplateDecl *TD = Class->getDescribedClassTemplate();
if (!TD) {
  auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(Class);
  if (!SD) {
    S.Diag(Class->getLocation(),
           diag::err_cuda_device_builtin_surftex_ref_decl)
        << /*surface*/ 0 << Class;
    S.Diag(Class->getLocation(),
           diag::note_cuda_device_builtin_surftex_should_be_template_class)
        << Class;
    return;
  }
  TD = SD->getSpecializedTemplate();
}

TemplateParameterList *Params = TD->getTemplateParameters();
unsigned N = Params->size();

if (N != 2) {
  reportIllegalClassTemplate(S, TD);
  S.Diag(TD->getLocation(),
         diag::note_cuda_device_builtin_surftex_cls_should_have_n_args)
      << TD << 2;
}
if (N > 0 && !isa<TemplateTypeParmDecl>(Params->getParam(0))) {
  reportIllegalClassTemplate(S, TD);
  S.Diag(TD->getLocation(),
         diag::note_cuda_device_builtin_surftex_cls_should_have_match_arg)
      << TD << /*1st*/ 0 << /*type*/ 0;
}
if (N > 1) {
  auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Params->getParam(1));
  if (!NTTP || !NTTP->getType()->isIntegralOrEnumerationType()) {
    reportIllegalClassTemplate(S, TD);
    S.Diag(TD->getLocation(),
           diag::note_cuda_device_builtin_surftex_cls_should_have_match_arg)
        << TD << /*2nd*/ 1 << /*integer*/ 1;
  }
}
6103}

6105static void checkCUDADeviceBuiltinTextureClassTemplate(Sema &S,
                                                     CXXRecordDecl *Class) {
bool ErrorReported = false;
auto reportIllegalClassTemplate = [&ErrorReported](Sema &S,
                                                   ClassTemplateDecl *TD) {
  if (ErrorReported)
    return;
  S.Diag(TD->getLocation(),
         diag::err_cuda_device_builtin_surftex_cls_template)
      << /*texture*/ 1 << TD;
  ErrorReported = true;
};

ClassTemplateDecl *TD = Class->getDescribedClassTemplate();
if (!TD) {
  auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(Class);
  if (!SD) {
    S.Diag(Class->getLocation(),
           diag::err_cuda_device_builtin_surftex_ref_decl)
        << /*texture*/ 1 << Class;
    S.Diag(Class->getLocation(),
           diag::note_cuda_device_builtin_surftex_should_be_template_class)
        << Class;
    return;
  }
  TD = SD->getSpecializedTemplate();
}

TemplateParameterList *Params = TD->getTemplateParameters();
unsigned N = Params->size();

if (N != 3) {
  reportIllegalClassTemplate(S, TD);
  S.Diag(TD->getLocation(),
         diag::note_cuda_device_builtin_surftex_cls_should_have_n_args)
      << TD << 3;
}
if (N > 0 && !isa<TemplateTypeParmDecl>(Params->getParam(0))) {
  reportIllegalClassTemplate(S, TD);
  S.Diag(TD->getLocation(),
         diag::note_cuda_device_builtin_surftex_cls_should_have_match_arg)
      << TD << /*1st*/ 0 << /*type*/ 0;
}
if (N > 1) {
  auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Params->getParam(1));
  if (!NTTP || !NTTP->getType()->isIntegralOrEnumerationType()) {
    reportIllegalClassTemplate(S, TD);
    S.Diag(TD->getLocation(),
           diag::note_cuda_device_builtin_surftex_cls_should_have_match_arg)
        << TD << /*2nd*/ 1 << /*integer*/ 1;
  }
}
if (N > 2) {
  auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Params->getParam(2));
  if (!NTTP || !NTTP->getType()->isIntegralOrEnumerationType()) {
    reportIllegalClassTemplate(S, TD);
    S.Diag(TD->getLocation(),
           diag::note_cuda_device_builtin_surftex_cls_should_have_match_arg)
        << TD << /*3rd*/ 2 << /*integer*/ 1;
  }
}
6166}

6168void Sema::checkClassLevelCodeSegAttribute(CXXRecordDecl *Class) {
// Mark any compiler-generated routines with the implicit code_seg attribute.
for (auto *Method : Class->methods()) {
  if (Method->isUserProvided())
    continue;
  if (Attr *A = getImplicitCodeSegOrSectionAttrForFunction(Method, /*IsDefinition=*/true))
    Method->addAttr(A);
}
6176}

6178/// Check class-level dllimport/dllexport attribute.
6179void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
Attr *ClassAttr = getDLLAttr(Class);

// MSVC inherits DLL attributes to partial class template specializations.
if (Context.getTargetInfo().shouldDLLImportComdatSymbols() && !ClassAttr) {
  if (auto *Spec = dyn_cast<ClassTemplatePartialSpecializationDecl>(Class)) {
    if (Attr *TemplateAttr =
            getDLLAttr(Spec->getSpecializedTemplate()->getTemplatedDecl())) {
      auto *A = cast<InheritableAttr>(TemplateAttr->clone(getASTContext()));
      A->setInherited(true);
      ClassAttr = A;
    }
  }
}

if (!ClassAttr)
  return;

if (!Class->isExternallyVisible()) {
  Diag(Class->getLocation(), diag::err_attribute_dll_not_extern)
      << Class << ClassAttr;
  return;
}

if (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
    !ClassAttr->isInherited()) {
  // Diagnose dll attributes on members of class with dll attribute.
  for (Decl *Member : Class->decls()) {
    if (!isa<VarDecl>(Member) && !isa<CXXMethodDecl>(Member))
      continue;
    InheritableAttr *MemberAttr = getDLLAttr(Member);
    if (!MemberAttr || MemberAttr->isInherited() || Member->isInvalidDecl())
      continue;

    Diag(MemberAttr->getLocation(),
           diag::err_attribute_dll_member_of_dll_class)
        << MemberAttr << ClassAttr;
    Diag(ClassAttr->getLocation(), diag::note_previous_attribute);
    Member->setInvalidDecl();
  }
}

if (Class->getDescribedClassTemplate())
  // Don't inherit dll attribute until the template is instantiated.
  return;

// The class is either imported or exported.
const bool ClassExported = ClassAttr->getKind() == attr::DLLExport;

// Check if this was a dllimport attribute propagated from a derived class to
// a base class template specialization. We don't apply these attributes to
// static data members.
const bool PropagatedImport =
    !ClassExported &&
    cast<DLLImportAttr>(ClassAttr)->wasPropagatedToBaseTemplate();

TemplateSpecializationKind TSK = Class->getTemplateSpecializationKind();

// Ignore explicit dllexport on explicit class template instantiation
// declarations, except in MinGW mode.
if (ClassExported && !ClassAttr->isInherited() &&
    TSK == TSK_ExplicitInstantiationDeclaration &&
    !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
  Class->dropAttr<DLLExportAttr>();
  return;
}

// Force declaration of implicit members so they can inherit the attribute.
ForceDeclarationOfImplicitMembers(Class);

// FIXME: MSVC's docs say all bases must be exportable, but this doesn't
// seem to be true in practice?

for (Decl *Member : Class->decls()) {
  VarDecl *VD = dyn_cast<VarDecl>(Member);
  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Member);

  // Only methods and static fields inherit the attributes.
  if (!VD && !MD)
    continue;

  if (MD) {
    // Don't process deleted methods.
    if (MD->isDeleted())
      continue;

    if (MD->isInlined()) {
      // MinGW does not import or export inline methods. But do it for
      // template instantiations.
      if (!Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
          TSK != TSK_ExplicitInstantiationDeclaration &&
          TSK != TSK_ExplicitInstantiationDefinition)
        continue;

      // MSVC versions before 2015 don't export the move assignment operators
      // and move constructor, so don't attempt to import/export them if
      // we have a definition.
      auto *Ctor = dyn_cast<CXXConstructorDecl>(MD);
      if ((MD->isMoveAssignmentOperator() ||
           (Ctor && Ctor->isMoveConstructor())) &&
          !getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
        continue;

      // MSVC2015 doesn't export trivial defaulted x-tor but copy assign
      // operator is exported anyway.
      if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015) &&
          (Ctor || isa<CXXDestructorDecl>(MD)) && MD->isTrivial())
        continue;
    }
  }

  // Don't apply dllimport attributes to static data members of class template
  // instantiations when the attribute is propagated from a derived class.
  if (VD && PropagatedImport)
    continue;

  if (!cast<NamedDecl>(Member)->isExternallyVisible())
    continue;

  if (!getDLLAttr(Member)) {
    InheritableAttr *NewAttr = nullptr;

    // Do not export/import inline function when -fno-dllexport-inlines is
    // passed. But add attribute for later local static var check.
    if (!getLangOpts().DllExportInlines && MD && MD->isInlined() &&
        TSK != TSK_ExplicitInstantiationDeclaration &&
        TSK != TSK_ExplicitInstantiationDefinition) {
      if (ClassExported) {
        NewAttr = ::new (getASTContext())
            DLLExportStaticLocalAttr(getASTContext(), *ClassAttr);
      } else {
        NewAttr = ::new (getASTContext())
            DLLImportStaticLocalAttr(getASTContext(), *ClassAttr);
      }
    } else {
      NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
    }

    NewAttr->setInherited(true);
    Member->addAttr(NewAttr);

    if (MD) {
      // Propagate DLLAttr to friend re-declarations of MD that have already
      // been constructed.
      for (FunctionDecl *FD = MD->getMostRecentDecl(); FD;
           FD = FD->getPreviousDecl()) {
        if (FD->getFriendObjectKind() == Decl::FOK_None)
          continue;
        assert(!getDLLAttr(FD) &&((void)0)
               "friend re-decl should not already have a DLLAttr")((void)0);
        NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
        NewAttr->setInherited(true);
        FD->addAttr(NewAttr);
      }
    }
  }
}

if (ClassExported)
  DelayedDllExportClasses.push_back(Class);
6339}

6341/// Perform propagation of DLL attributes from a derived class to a
6342/// templated base class for MS compatibility.
6343void Sema::propagateDLLAttrToBaseClassTemplate(
  CXXRecordDecl *Class, Attr *ClassAttr,
  ClassTemplateSpecializationDecl *BaseTemplateSpec, SourceLocation BaseLoc) {
if (getDLLAttr(
        BaseTemplateSpec->getSpecializedTemplate()->getTemplatedDecl())) {
  // If the base class template has a DLL attribute, don't try to change it.
  return;
}

auto TSK = BaseTemplateSpec->getSpecializationKind();
if (!getDLLAttr(BaseTemplateSpec) &&
    (TSK == TSK_Undeclared || TSK == TSK_ExplicitInstantiationDeclaration ||
     TSK == TSK_ImplicitInstantiation)) {
  // The template hasn't been instantiated yet (or it has, but only as an
  // explicit instantiation declaration or implicit instantiation, which means
  // we haven't codegenned any members yet), so propagate the attribute.
  auto *NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
  NewAttr->setInherited(true);
  BaseTemplateSpec->addAttr(NewAttr);

  // If this was an import, mark that we propagated it from a derived class to
  // a base class template specialization.
  if (auto *ImportAttr = dyn_cast<DLLImportAttr>(NewAttr))
    ImportAttr->setPropagatedToBaseTemplate();

  // If the template is already instantiated, checkDLLAttributeRedeclaration()
  // needs to be run again to work see the new attribute. Otherwise this will
  // get run whenever the template is instantiated.
  if (TSK != TSK_Undeclared)
    checkClassLevelDLLAttribute(BaseTemplateSpec);

  return;
}

if (getDLLAttr(BaseTemplateSpec)) {
  // The template has already been specialized or instantiated with an
  // attribute, explicitly or through propagation. We should not try to change
  // it.
  return;
}

// The template was previously instantiated or explicitly specialized without
// a dll attribute, It's too late for us to add an attribute, so warn that
// this is unsupported.
Diag(BaseLoc, diag::warn_attribute_dll_instantiated_base_class)
    << BaseTemplateSpec->isExplicitSpecialization();
Diag(ClassAttr->getLocation(), diag::note_attribute);
if (BaseTemplateSpec->isExplicitSpecialization()) {
  Diag(BaseTemplateSpec->getLocation(),
         diag::note_template_class_explicit_specialization_was_here)
      << BaseTemplateSpec;
} else {
  Diag(BaseTemplateSpec->getPointOfInstantiation(),
         diag::note_template_class_instantiation_was_here)
      << BaseTemplateSpec;
}
6399}

6401/// Determine the kind of defaulting that would be done for a given function.
6402///
6403/// If the function is both a default constructor and a copy / move constructor
6404/// (due to having a default argument for the first parameter), this picks
6405/// CXXDefaultConstructor.
6406///
6407/// FIXME: Check that case is properly handled by all callers.
6408Sema::DefaultedFunctionKind
6409Sema::getDefaultedFunctionKind(const FunctionDecl *FD) {
if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
  if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(FD)) {
    if (Ctor->isDefaultConstructor())
      return Sema::CXXDefaultConstructor;

    if (Ctor->isCopyConstructor())
      return Sema::CXXCopyConstructor;

    if (Ctor->isMoveConstructor())
      return Sema::CXXMoveConstructor;
  }

  if (MD->isCopyAssignmentOperator())
    return Sema::CXXCopyAssignment;

  if (MD->isMoveAssignmentOperator())
    return Sema::CXXMoveAssignment;

  if (isa<CXXDestructorDecl>(FD))
    return Sema::CXXDestructor;
}

switch (FD->getDeclName().getCXXOverloadedOperator()) {
case OO_EqualEqual:
  return DefaultedComparisonKind::Equal;

case OO_ExclaimEqual:
  return DefaultedComparisonKind::NotEqual;

case OO_Spaceship:
  // No point allowing this if <=> doesn't exist in the current language mode.
  if (!getLangOpts().CPlusPlus20)
    break;
  return DefaultedComparisonKind::ThreeWay;

case OO_Less:
case OO_LessEqual:
case OO_Greater:
case OO_GreaterEqual:
  // No point allowing this if <=> doesn't exist in the current language mode.
  if (!getLangOpts().CPlusPlus20)
    break;
  return DefaultedComparisonKind::Relational;

default:
  break;
}

// Not defaultable.
return DefaultedFunctionKind();
6460}

6462static void DefineDefaultedFunction(Sema &S, FunctionDecl *FD,
                                  SourceLocation DefaultLoc) {
Sema::DefaultedFunctionKind DFK = S.getDefaultedFunctionKind(FD);
if (DFK.isComparison())
  return S.DefineDefaultedComparison(DefaultLoc, FD, DFK.asComparison());

switch (DFK.asSpecialMember()) {
case Sema::CXXDefaultConstructor:
  S.DefineImplicitDefaultConstructor(DefaultLoc,
                                     cast<CXXConstructorDecl>(FD));
  break;
case Sema::CXXCopyConstructor:
  S.DefineImplicitCopyConstructor(DefaultLoc, cast<CXXConstructorDecl>(FD));
  break;
case Sema::CXXCopyAssignment:
  S.DefineImplicitCopyAssignment(DefaultLoc, cast<CXXMethodDecl>(FD));
  break;
case Sema::CXXDestructor:
  S.DefineImplicitDestructor(DefaultLoc, cast<CXXDestructorDecl>(FD));
  break;
case Sema::CXXMoveConstructor:
  S.DefineImplicitMoveConstructor(DefaultLoc, cast<CXXConstructorDecl>(FD));
  break;
case Sema::CXXMoveAssignment:
  S.DefineImplicitMoveAssignment(DefaultLoc, cast<CXXMethodDecl>(FD));
  break;
case Sema::CXXInvalid:
  llvm_unreachable("Invalid special member.")__builtin_unreachable();
}
6491}

6493/// Determine whether a type is permitted to be passed or returned in
6494/// registers, per C++ [class.temporary]p3.
6495static bool canPassInRegisters(Sema &S, CXXRecordDecl *D,
                             TargetInfo::CallingConvKind CCK) {
if (D->isDependentType() || D->isInvalidDecl())
  return false;

// Clang <= 4 used the pre-C++11 rule, which ignores move operations.
// The PS4 platform ABI follows the behavior of Clang 3.2.
if (CCK == TargetInfo::CCK_ClangABI4OrPS4)
  return !D->hasNonTrivialDestructorForCall() &&
         !D->hasNonTrivialCopyConstructorForCall();

if (CCK == TargetInfo::CCK_MicrosoftWin64) {
  bool CopyCtorIsTrivial = false, CopyCtorIsTrivialForCall = false;
  bool DtorIsTrivialForCall = false;

  // If a class has at least one non-deleted, trivial copy constructor, it
  // is passed according to the C ABI. Otherwise, it is passed indirectly.
  //
  // Note: This permits classes with non-trivial copy or move ctors to be
  // passed in registers, so long as they *also* have a trivial copy ctor,
  // which is non-conforming.
  if (D->needsImplicitCopyConstructor()) {
    if (!D->defaultedCopyConstructorIsDeleted()) {
      if (D->hasTrivialCopyConstructor())
        CopyCtorIsTrivial = true;
      if (D->hasTrivialCopyConstructorForCall())
        CopyCtorIsTrivialForCall = true;
    }
  } else {
    for (const CXXConstructorDecl *CD : D->ctors()) {
      if (CD->isCopyConstructor() && !CD->isDeleted()) {
        if (CD->isTrivial())
          CopyCtorIsTrivial = true;
        if (CD->isTrivialForCall())
          CopyCtorIsTrivialForCall = true;
      }
    }
  }

  if (D->needsImplicitDestructor()) {
    if (!D->defaultedDestructorIsDeleted() &&
        D->hasTrivialDestructorForCall())
      DtorIsTrivialForCall = true;
  } else if (const auto *DD = D->getDestructor()) {
    if (!DD->isDeleted() && DD->isTrivialForCall())
      DtorIsTrivialForCall = true;
  }

  // If the copy ctor and dtor are both trivial-for-calls, pass direct.
  if (CopyCtorIsTrivialForCall && DtorIsTrivialForCall)
    return true;

  // If a class has a destructor, we'd really like to pass it indirectly
  // because it allows us to elide copies.  Unfortunately, MSVC makes that
  // impossible for small types, which it will pass in a single register or
  // stack slot. Most objects with dtors are large-ish, so handle that early.
  // We can't call out all large objects as being indirect because there are
  // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
  // how we pass large POD types.

  // Note: This permits small classes with nontrivial destructors to be
  // passed in registers, which is non-conforming.
  bool isAArch64 = S.Context.getTargetInfo().getTriple().isAArch64();
  uint64_t TypeSize = isAArch64 ? 128 : 64;

  if (CopyCtorIsTrivial &&
      S.getASTContext().getTypeSize(D->getTypeForDecl()) <= TypeSize)
    return true;
  return false;
}

// Per C++ [class.temporary]p3, the relevant condition is:
//   each copy constructor, move constructor, and destructor of X is
//   either trivial or deleted, and X has at least one non-deleted copy
//   or move constructor
bool HasNonDeletedCopyOrMove = false;

if (D->needsImplicitCopyConstructor() &&
    !D->defaultedCopyConstructorIsDeleted()) {
  if (!D->hasTrivialCopyConstructorForCall())
    return false;
  HasNonDeletedCopyOrMove = true;
}

if (S.getLangOpts().CPlusPlus11 && D->needsImplicitMoveConstructor() &&
    !D->defaultedMoveConstructorIsDeleted()) {
  if (!D->hasTrivialMoveConstructorForCall())
    return false;
  HasNonDeletedCopyOrMove = true;
}

if (D->needsImplicitDestructor() && !D->defaultedDestructorIsDeleted() &&
    !D->hasTrivialDestructorForCall())
  return false;

for (const CXXMethodDecl *MD : D->methods()) {
  if (MD->isDeleted())
    continue;

  auto *CD = dyn_cast<CXXConstructorDecl>(MD);
  if (CD && CD->isCopyOrMoveConstructor())
    HasNonDeletedCopyOrMove = true;
  else if (!isa<CXXDestructorDecl>(MD))
    continue;

  if (!MD->isTrivialForCall())
    return false;
}

return HasNonDeletedCopyOrMove;
6605}

6607/// Report an error regarding overriding, along with any relevant
6608/// overridden methods.
6609///
6610/// \param DiagID the primary error to report.
6611/// \param MD the overriding method.
6612static bool
6613ReportOverrides(Sema &S, unsigned DiagID, const CXXMethodDecl *MD,
              llvm::function_ref<bool(const CXXMethodDecl *)> Report) {
bool IssuedDiagnostic = false;
for (const CXXMethodDecl *O : MD->overridden_methods()) {
  if (Report(O)) {
    if (!IssuedDiagnostic) {
      S.Diag(MD->getLocation(), DiagID) << MD->getDeclName();
      IssuedDiagnostic = true;
    }
    S.Diag(O->getLocation(), diag::note_overridden_virtual_function);
  }
}
return IssuedDiagnostic;
6626}

6628/// Perform semantic checks on a class definition that has been
6629/// completing, introducing implicitly-declared members, checking for
6630/// abstract types, etc.
6631///
6632/// \param S The scope in which the class was parsed. Null if we didn't just
6633///        parse a class definition.
6634/// \param Record The completed class.
6635void Sema::CheckCompletedCXXClass(Scope *S, CXXRecordDecl *Record) {
if (!Record)
  return;

if (Record->isAbstract() && !Record->isInvalidDecl()) {
  AbstractUsageInfo Info(*this, Record);
  CheckAbstractClassUsage(Info, Record);
}

// If this is not an aggregate type and has no user-declared constructor,
// complain about any non-static data members of reference or const scalar
// type, since they will never get initializers.
if (!Record->isInvalidDecl() && !Record->isDependentType() &&
    !Record->isAggregate() && !Record->hasUserDeclaredConstructor() &&
    !Record->isLambda()) {
  bool Complained = false;
  for (const auto *F : Record->fields()) {
    if (F->hasInClassInitializer() || F->isUnnamedBitfield())
      continue;

    if (F->getType()->isReferenceType() ||
        (F->getType().isConstQualified() && F->getType()->isScalarType())) {
      if (!Complained) {
        Diag(Record->getLocation(), diag::warn_no_constructor_for_refconst)
          << Record->getTagKind() << Record;
        Complained = true;
      }

      Diag(F->getLocation(), diag::note_refconst_member_not_initialized)
        << F->getType()->isReferenceType()
        << F->getDeclName();
    }
  }
}

if (Record->getIdentifier()) {
  // C++ [class.mem]p13:
  //   If T is the name of a class, then each of the following shall have a
  //   name different from T:
  //     - every member of every anonymous union that is a member of class T.
  //
  // C++ [class.mem]p14:
  //   In addition, if class T has a user-declared constructor (12.1), every
  //   non-static data member of class T shall have a name different from T.
  DeclContext::lookup_result R = Record->lookup(Record->getDeclName());
  for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E;
       ++I) {
    NamedDecl *D = (*I)->getUnderlyingDecl();
    if (((isa<FieldDecl>(D) || isa<UnresolvedUsingValueDecl>(D)) &&
         Record->hasUserDeclaredConstructor()) ||
        isa<IndirectFieldDecl>(D)) {
      Diag((*I)->getLocation(), diag::err_member_name_of_class)
        << D->getDeclName();
      break;
    }
  }
}

// Warn if the class has virtual methods but non-virtual public destructor.
if (Record->isPolymorphic() && !Record->isDependentType()) {
  CXXDestructorDecl *dtor = Record->getDestructor();
  if ((!dtor || (!dtor->isVirtual() && dtor->getAccess() == AS_public)) &&
      !Record->hasAttr<FinalAttr>())
    Diag(dtor ? dtor->getLocation() : Record->getLocation(),
         diag::warn_non_virtual_dtor) << Context.getRecordType(Record);
}

if (Record->isAbstract()) {
  if (FinalAttr *FA = Record->getAttr<FinalAttr>()) {
    Diag(Record->getLocation(), diag::warn_abstract_final_class)
      << FA->isSpelledAsSealed();
    DiagnoseAbstractType(Record);
  }
}

// Warn if the class has a final destructor but is not itself marked final.
if (!Record->hasAttr<FinalAttr>()) {
  if (const CXXDestructorDecl *dtor = Record->getDestructor()) {
    if (const FinalAttr *FA = dtor->getAttr<FinalAttr>()) {
      Diag(FA->getLocation(), diag::warn_final_dtor_non_final_class)
          << FA->isSpelledAsSealed()
          << FixItHint::CreateInsertion(
                 getLocForEndOfToken(Record->getLocation()),
                 (FA->isSpelledAsSealed() ? " sealed" : " final"));
      Diag(Record->getLocation(),
           diag::note_final_dtor_non_final_class_silence)
          << Context.getRecordType(Record) << FA->isSpelledAsSealed();
    }
  }
}

// See if trivial_abi has to be dropped.
if (Record->hasAttr<TrivialABIAttr>())
  checkIllFormedTrivialABIStruct(*Record);

// Set HasTrivialSpecialMemberForCall if the record has attribute
// "trivial_abi".
bool HasTrivialABI = Record->hasAttr<TrivialABIAttr>();

if (HasTrivialABI)
  Record->setHasTrivialSpecialMemberForCall();

// Explicitly-defaulted secondary comparison functions (!=, <, <=, >, >=).
// We check these last because they can depend on the properties of the
// primary comparison functions (==, <=>).
llvm::SmallVector<FunctionDecl*, 5> DefaultedSecondaryComparisons;

// Perform checks that can't be done until we know all the properties of a
// member function (whether it's defaulted, deleted, virtual, overriding,
// ...).
auto CheckCompletedMemberFunction = [&](CXXMethodDecl *MD) {
  // A static function cannot override anything.
  if (MD->getStorageClass() == SC_Static) {
    if (ReportOverrides(*this, diag::err_static_overrides_virtual, MD,
                        [](const CXXMethodDecl *) { return true; }))
      return;
  }

  // A deleted function cannot override a non-deleted function and vice
  // versa.
  if (ReportOverrides(*this,
                      MD->isDeleted() ? diag::err_deleted_override
                                      : diag::err_non_deleted_override,
                      MD, [&](const CXXMethodDecl *V) {
                        return MD->isDeleted() != V->isDeleted();
                      })) {
    if (MD->isDefaulted() && MD->isDeleted())
      // Explain why this defaulted function was deleted.
      DiagnoseDeletedDefaultedFunction(MD);
    return;
  }

  // A consteval function cannot override a non-consteval function and vice
  // versa.
  if (ReportOverrides(*this,
                      MD->isConsteval() ? diag::err_consteval_override
                                        : diag::err_non_consteval_override,
                      MD, [&](const CXXMethodDecl *V) {
                        return MD->isConsteval() != V->isConsteval();
                      })) {
    if (MD->isDefaulted() && MD->isDeleted())
      // Explain why this defaulted function was deleted.
      DiagnoseDeletedDefaultedFunction(MD);
    return;
  }
};

auto CheckForDefaultedFunction = [&](FunctionDecl *FD) -> bool {
  if (!FD || FD->isInvalidDecl() || !FD->isExplicitlyDefaulted())
    return false;

  DefaultedFunctionKind DFK = getDefaultedFunctionKind(FD);
  if (DFK.asComparison() == DefaultedComparisonKind::NotEqual ||
      DFK.asComparison() == DefaultedComparisonKind::Relational) {
    DefaultedSecondaryComparisons.push_back(FD);
    return true;
  }

  CheckExplicitlyDefaultedFunction(S, FD);
  return false;
};

auto CompleteMemberFunction = [&](CXXMethodDecl *M) {
  // Check whether the explicitly-defaulted members are valid.
  bool Incomplete = CheckForDefaultedFunction(M);

  // Skip the rest of the checks for a member of a dependent class.
  if (Record->isDependentType())
    return;

  // For an explicitly defaulted or deleted special member, we defer
  // determining triviality until the class is complete. That time is now!
  CXXSpecialMember CSM = getSpecialMember(M);
  if (!M->isImplicit() && !M->isUserProvided()) {
    if (CSM != CXXInvalid) {
      M->setTrivial(SpecialMemberIsTrivial(M, CSM));
      // Inform the class that we've finished declaring this member.
      Record->finishedDefaultedOrDeletedMember(M);
      M->setTrivialForCall(
          HasTrivialABI ||
          SpecialMemberIsTrivial(M, CSM, TAH_ConsiderTrivialABI));
      Record->setTrivialForCallFlags(M);
    }
  }

  // Set triviality for the purpose of calls if this is a user-provided
  // copy/move constructor or destructor.
  if ((CSM == CXXCopyConstructor || CSM == CXXMoveConstructor ||
       CSM == CXXDestructor) && M->isUserProvided()) {
    M->setTrivialForCall(HasTrivialABI);
    Record->setTrivialForCallFlags(M);
  }

  if (!M->isInvalidDecl() && M->isExplicitlyDefaulted() &&
      M->hasAttr<DLLExportAttr>()) {
    if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015) &&
        M->isTrivial() &&
        (CSM == CXXDefaultConstructor || CSM == CXXCopyConstructor ||
         CSM == CXXDestructor))
      M->dropAttr<DLLExportAttr>();

    if (M->hasAttr<DLLExportAttr>()) {
      // Define after any fields with in-class initializers have been parsed.
      DelayedDllExportMemberFunctions.push_back(M);
    }
  }

  // Define defaulted constexpr virtual functions that override a base class
  // function right away.
  // FIXME: We can defer doing this until the vtable is marked as used.
  if (M->isDefaulted() && M->isConstexpr() && M->size_overridden_methods())
    DefineDefaultedFunction(*this, M, M->getLocation());

  if (!Incomplete)
    CheckCompletedMemberFunction(M);
};

// Check the destructor before any other member function. We need to
// determine whether it's trivial in order to determine whether the claas
// type is a literal type, which is a prerequisite for determining whether
// other special member functions are valid and whether they're implicitly
// 'constexpr'.
if (CXXDestructorDecl *Dtor = Record->getDestructor())
  CompleteMemberFunction(Dtor);

bool HasMethodWithOverrideControl = false,
     HasOverridingMethodWithoutOverrideControl = false;
for (auto *D : Record->decls()) {
  if (auto *M = dyn_cast<CXXMethodDecl>(D)) {
    // FIXME: We could do this check for dependent types with non-dependent
    // bases.
    if (!Record->isDependentType()) {
      // See if a method overloads virtual methods in a base
      // class without overriding any.
      if (!M->isStatic())
        DiagnoseHiddenVirtualMethods(M);
      if (M->hasAttr<OverrideAttr>())
        HasMethodWithOverrideControl = true;
      else if (M->size_overridden_methods() > 0)
        HasOverridingMethodWithoutOverrideControl = true;
    }

    if (!isa<CXXDestructorDecl>(M))
      CompleteMemberFunction(M);
  } else if (auto *F = dyn_cast<FriendDecl>(D)) {
    CheckForDefaultedFunction(
        dyn_cast_or_null<FunctionDecl>(F->getFriendDecl()));
  }
}

if (HasOverridingMethodWithoutOverrideControl) {
  bool HasInconsistentOverrideControl = HasMethodWithOverrideControl;
  for (auto *M : Record->methods())
    DiagnoseAbsenceOfOverrideControl(M, HasInconsistentOverrideControl);
}

// Check the defaulted secondary comparisons after any other member functions.
for (FunctionDecl *FD : DefaultedSecondaryComparisons) {
  CheckExplicitlyDefaultedFunction(S, FD);

  // If this is a member function, we deferred checking it until now.
  if (auto *MD = dyn_cast<CXXMethodDecl>(FD))
    CheckCompletedMemberFunction(MD);
}

// ms_struct is a request to use the same ABI rules as MSVC.  Check
// whether this class uses any C++ features that are implemented
// completely differently in MSVC, and if so, emit a diagnostic.
// That diagnostic defaults to an error, but we allow projects to
// map it down to a warning (or ignore it).  It's a fairly common
// practice among users of the ms_struct pragma to mass-annotate
// headers, sweeping up a bunch of types that the project doesn't
// really rely on MSVC-compatible layout for.  We must therefore
// support "ms_struct except for C++ stuff" as a secondary ABI.
// Don't emit this diagnostic if the feature was enabled as a
// language option (as opposed to via a pragma or attribute), as
// the option -mms-bitfields otherwise essentially makes it impossible
// to build C++ code, unless this diagnostic is turned off.
if (Record->isMsStruct(Context) && !Context.getLangOpts().MSBitfields &&
    (Record->isPolymorphic() || Record->getNumBases())) {
  Diag(Record->getLocation(), diag::warn_cxx_ms_struct);
}

checkClassLevelDLLAttribute(Record);
checkClassLevelCodeSegAttribute(Record);

bool ClangABICompat4 =
    Context.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver4;
TargetInfo::CallingConvKind CCK =
    Context.getTargetInfo().getCallingConvKind(ClangABICompat4);
bool CanPass = canPassInRegisters(*this, Record, CCK);

// Do not change ArgPassingRestrictions if it has already been set to
// APK_CanNeverPassInRegs.
if (Record->getArgPassingRestrictions() != RecordDecl::APK_CanNeverPassInRegs)
  Record->setArgPassingRestrictions(CanPass
                                        ? RecordDecl::APK_CanPassInRegs
                                        : RecordDecl::APK_CannotPassInRegs);

// If canPassInRegisters returns true despite the record having a non-trivial
// destructor, the record is destructed in the callee. This happens only when
// the record or one of its subobjects has a field annotated with trivial_abi
// or a field qualified with ObjC __strong/__weak.
if (Context.getTargetInfo().getCXXABI().areArgsDestroyedLeftToRightInCallee())
  Record->setParamDestroyedInCallee(true);
else if (Record->hasNonTrivialDestructor())
  Record->setParamDestroyedInCallee(CanPass);

if (getLangOpts().ForceEmitVTables) {
  // If we want to emit all the vtables, we need to mark it as used.  This
  // is especially required for cases like vtable assumption loads.
  MarkVTableUsed(Record->getInnerLocStart(), Record);
}

if (getLangOpts().CUDA) {
  if (Record->hasAttr<CUDADeviceBuiltinSurfaceTypeAttr>())
    checkCUDADeviceBuiltinSurfaceClassTemplate(*this, Record);
  else if (Record->hasAttr<CUDADeviceBuiltinTextureTypeAttr>())
    checkCUDADeviceBuiltinTextureClassTemplate(*this, Record);
}
6955}

6957/// Look up the special member function that would be called by a special
6958/// member function for a subobject of class type.
6959///
6960/// \param Class The class type of the subobject.
6961/// \param CSM The kind of special member function.
6962/// \param FieldQuals If the subobject is a field, its cv-qualifiers.
6963/// \param ConstRHS True if this is a copy operation with a const object
6964///        on its RHS, that is, if the argument to the outer special member
6965///        function is 'const' and this is not a field marked 'mutable'.
6966static Sema::SpecialMemberOverloadResult lookupCallFromSpecialMember(
  Sema &S, CXXRecordDecl *Class, Sema::CXXSpecialMember CSM,
  unsigned FieldQuals, bool ConstRHS) {
unsigned LHSQuals = 0;
if (CSM == Sema::CXXCopyAssignment || CSM == Sema::CXXMoveAssignment)
  LHSQuals = FieldQuals;

unsigned RHSQuals = FieldQuals;
if (CSM == Sema::CXXDefaultConstructor || CSM == Sema::CXXDestructor)
  RHSQuals = 0;
else if (ConstRHS)
  RHSQuals |= Qualifiers::Const;

return S.LookupSpecialMember(Class, CSM,
                             RHSQuals & Qualifiers::Const,
                             RHSQuals & Qualifiers::Volatile,
                             false,
                             LHSQuals & Qualifiers::Const,
                             LHSQuals & Qualifiers::Volatile);
6985}

6987class Sema::InheritedConstructorInfo {
Sema &S;
SourceLocation UseLoc;

/// A mapping from the base classes through which the constructor was
/// inherited to the using shadow declaration in that base class (or a null
/// pointer if the constructor was declared in that base class).
llvm::DenseMap<CXXRecordDecl *, ConstructorUsingShadowDecl *>
    InheritedFromBases;

6997public:
InheritedConstructorInfo(Sema &S, SourceLocation UseLoc,
                         ConstructorUsingShadowDecl *Shadow)
    : S(S), UseLoc(UseLoc) {
  bool DiagnosedMultipleConstructedBases = false;
  CXXRecordDecl *ConstructedBase = nullptr;
  BaseUsingDecl *ConstructedBaseIntroducer = nullptr;

  // Find the set of such base class subobjects and check that there's a
  // unique constructed subobject.
  for (auto *D : Shadow->redecls()) {
    auto *DShadow = cast<ConstructorUsingShadowDecl>(D);
    auto *DNominatedBase = DShadow->getNominatedBaseClass();
    auto *DConstructedBase = DShadow->getConstructedBaseClass();

    InheritedFromBases.insert(
        std::make_pair(DNominatedBase->getCanonicalDecl(),
                       DShadow->getNominatedBaseClassShadowDecl()));
    if (DShadow->constructsVirtualBase())
      InheritedFromBases.insert(
          std::make_pair(DConstructedBase->getCanonicalDecl(),
                         DShadow->getConstructedBaseClassShadowDecl()));
    else
      assert(DNominatedBase == DConstructedBase)((void)0);

    // [class.inhctor.init]p2:
    //   If the constructor was inherited from multiple base class subobjects
    //   of type B, the program is ill-formed.
    if (!ConstructedBase) {
      ConstructedBase = DConstructedBase;
      ConstructedBaseIntroducer = D->getIntroducer();
    } else if (ConstructedBase != DConstructedBase &&
               !Shadow->isInvalidDecl()) {
      if (!DiagnosedMultipleConstructedBases) {
        S.Diag(UseLoc, diag::err_ambiguous_inherited_constructor)
            << Shadow->getTargetDecl();
        S.Diag(ConstructedBaseIntroducer->getLocation(),
               diag::note_ambiguous_inherited_constructor_using)
            << ConstructedBase;
        DiagnosedMultipleConstructedBases = true;
      }
      S.Diag(D->getIntroducer()->getLocation(),
             diag::note_ambiguous_inherited_constructor_using)
          << DConstructedBase;
    }
  }

  if (DiagnosedMultipleConstructedBases)
    Shadow->setInvalidDecl();
}

/// Find the constructor to use for inherited construction of a base class,
/// and whether that base class constructor inherits the constructor from a
/// virtual base class (in which case it won't actually invoke it).
std::pair<CXXConstructorDecl *, bool>
findConstructorForBase(CXXRecordDecl *Base, CXXConstructorDecl *Ctor) const {
  auto It = InheritedFromBases.find(Base->getCanonicalDecl());
  if (It == InheritedFromBases.end())
    return std::make_pair(nullptr, false);

  // This is an intermediary class.
  if (It->second)
    return std::make_pair(
        S.findInheritingConstructor(UseLoc, Ctor, It->second),
        It->second->constructsVirtualBase());

  // This is the base class from which the constructor was inherited.
  return std::make_pair(Ctor, false);
}
7066};

7068/// Is the special member function which would be selected to perform the
7069/// specified operation on the specified class type a constexpr constructor?
7070static bool
7071specialMemberIsConstexpr(Sema &S, CXXRecordDecl *ClassDecl,
                       Sema::CXXSpecialMember CSM, unsigned Quals,
                       bool ConstRHS,
                       CXXConstructorDecl *InheritedCtor = nullptr,
                       Sema::InheritedConstructorInfo *Inherited = nullptr) {
// If we're inheriting a constructor, see if we need to call it for this base
// class.
if (InheritedCtor) {
  assert(CSM == Sema::CXXDefaultConstructor)((void)0);
  auto BaseCtor =
      Inherited->findConstructorForBase(ClassDecl, InheritedCtor).first;
  if (BaseCtor)
    return BaseCtor->isConstexpr();
}

if (CSM == Sema::CXXDefaultConstructor)
  return ClassDecl->hasConstexprDefaultConstructor();
if (CSM == Sema::CXXDestructor)
  return ClassDecl->hasConstexprDestructor();

Sema::SpecialMemberOverloadResult SMOR =
    lookupCallFromSpecialMember(S, ClassDecl, CSM, Quals, ConstRHS);
if (!SMOR.getMethod())
  // A constructor we wouldn't select can't be "involved in initializing"
  // anything.
  return true;
return SMOR.getMethod()->isConstexpr();
7098}

7100/// Determine whether the specified special member function would be constexpr
7101/// if it were implicitly defined.
7102static bool defaultedSpecialMemberIsConstexpr(
  Sema &S, CXXRecordDecl *ClassDecl, Sema::CXXSpecialMember CSM,
  bool ConstArg, CXXConstructorDecl *InheritedCtor = nullptr,
  Sema::InheritedConstructorInfo *Inherited = nullptr) {
if (!S.getLangOpts().CPlusPlus11)
  return false;

// C++11 [dcl.constexpr]p4:
// In the definition of a constexpr constructor [...]
bool Ctor = true;
switch (CSM) {
case Sema::CXXDefaultConstructor:
  if (Inherited)
    break;
  // Since default constructor lookup is essentially trivial (and cannot
  // involve, for instance, template instantiation), we compute whether a
  // defaulted default constructor is constexpr directly within CXXRecordDecl.
  //
  // This is important for performance; we need to know whether the default
  // constructor is constexpr to determine whether the type is a literal type.
  return ClassDecl->defaultedDefaultConstructorIsConstexpr();

case Sema::CXXCopyConstructor:
case Sema::CXXMoveConstructor:
  // For copy or move constructors, we need to perform overload resolution.
  break;

case Sema::CXXCopyAssignment:
case Sema::CXXMoveAssignment:
  if (!S.getLangOpts().CPlusPlus14)
    return false;
  // In C++1y, we need to perform overload resolution.
  Ctor = false;
  break;

case Sema::CXXDestructor:
  return ClassDecl->defaultedDestructorIsConstexpr();

case Sema::CXXInvalid:
  return false;
}

//   -- if the class is a non-empty union, or for each non-empty anonymous
//      union member of a non-union class, exactly one non-static data member
//      shall be initialized; [DR1359]
//
// If we squint, this is guaranteed, since exactly one non-static data member
// will be initialized (if the constructor isn't deleted), we just don't know
// which one.
if (Ctor && ClassDecl->isUnion())
  return CSM == Sema::CXXDefaultConstructor
             ? ClassDecl->hasInClassInitializer() ||
                   !ClassDecl->hasVariantMembers()
             : true;

//   -- the class shall not have any virtual base classes;
if (Ctor && ClassDecl->getNumVBases())
  return false;

// C++1y [class.copy]p26:
//   -- [the class] is a literal type, and
if (!Ctor && !ClassDecl->isLiteral())
  return false;

//   -- every constructor involved in initializing [...] base class
//      sub-objects shall be a constexpr constructor;
//   -- the assignment operator selected to copy/move each direct base
//      class is a constexpr function, and
for (const auto &B : ClassDecl->bases()) {
  const RecordType *BaseType = B.getType()->getAs<RecordType>();
  if (!BaseType) continue;

  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseType->getDecl());
  if (!specialMemberIsConstexpr(S, BaseClassDecl, CSM, 0, ConstArg,
                                InheritedCtor, Inherited))
    return false;
}

//   -- every constructor involved in initializing non-static data members
//      [...] shall be a constexpr constructor;
//   -- every non-static data member and base class sub-object shall be
//      initialized
//   -- for each non-static data member of X that is of class type (or array
//      thereof), the assignment operator selected to copy/move that member is
//      a constexpr function
for (const auto *F : ClassDecl->fields()) {
  if (F->isInvalidDecl())
    continue;
  if (CSM == Sema::CXXDefaultConstructor && F->hasInClassInitializer())
    continue;
  QualType BaseType = S.Context.getBaseElementType(F->getType());
  if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
    CXXRecordDecl *FieldRecDecl = cast<CXXRecordDecl>(RecordTy->getDecl());
    if (!specialMemberIsConstexpr(S, FieldRecDecl, CSM,
                                  BaseType.getCVRQualifiers(),
                                  ConstArg && !F->isMutable()))
      return false;
  } else if (CSM == Sema::CXXDefaultConstructor) {
    return false;
  }
}

// All OK, it's constexpr!
return true;
7206}

7208namespace {
7209/// RAII object to register a defaulted function as having its exception
7210/// specification computed.
7211struct ComputingExceptionSpec {
Sema &S;

ComputingExceptionSpec(Sema &S, FunctionDecl *FD, SourceLocation Loc)
    : S(S) {
  Sema::CodeSynthesisContext Ctx;
  Ctx.Kind = Sema::CodeSynthesisContext::ExceptionSpecEvaluation;
  Ctx.PointOfInstantiation = Loc;
  Ctx.Entity = FD;
  S.pushCodeSynthesisContext(Ctx);
}
~ComputingExceptionSpec() {
  S.popCodeSynthesisContext();
}
7225};
7226}

7228static Sema::ImplicitExceptionSpecification
7229ComputeDefaultedSpecialMemberExceptionSpec(
  Sema &S, SourceLocation Loc, CXXMethodDecl *MD, Sema::CXXSpecialMember CSM,
  Sema::InheritedConstructorInfo *ICI);

7233static Sema::ImplicitExceptionSpecification
7234ComputeDefaultedComparisonExceptionSpec(Sema &S, SourceLocation Loc,
                                      FunctionDecl *FD,
                                      Sema::DefaultedComparisonKind DCK);

7238static Sema::ImplicitExceptionSpecification
7239computeImplicitExceptionSpec(Sema &S, SourceLocation Loc, FunctionDecl *FD) {
auto DFK = S.getDefaultedFunctionKind(FD);
if (DFK.isSpecialMember())
  return ComputeDefaultedSpecialMemberExceptionSpec(
      S, Loc, cast<CXXMethodDecl>(FD), DFK.asSpecialMember(), nullptr);
if (DFK.isComparison())
  return ComputeDefaultedComparisonExceptionSpec(S, Loc, FD,
                                                 DFK.asComparison());

auto *CD = cast<CXXConstructorDecl>(FD);
assert(CD->getInheritedConstructor() &&((void)0)
       "only defaulted functions and inherited constructors have implicit "((void)0)
       "exception specs")((void)0);
Sema::InheritedConstructorInfo ICI(
    S, Loc, CD->getInheritedConstructor().getShadowDecl());
return ComputeDefaultedSpecialMemberExceptionSpec(
    S, Loc, CD, Sema::CXXDefaultConstructor, &ICI);
7256}

7258static FunctionProtoType::ExtProtoInfo getImplicitMethodEPI(Sema &S,
                                                          CXXMethodDecl *MD) {
FunctionProtoType::ExtProtoInfo EPI;

// Build an exception specification pointing back at this member.
EPI.ExceptionSpec.Type = EST_Unevaluated;
EPI.ExceptionSpec.SourceDecl = MD;

// Set the calling convention to the default for C++ instance methods.
EPI.ExtInfo = EPI.ExtInfo.withCallingConv(
    S.Context.getDefaultCallingConvention(/*IsVariadic=*/false,
                                          /*IsCXXMethod=*/true));
return EPI;
7271}

7273void Sema::EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD) {
const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
if (FPT->getExceptionSpecType() != EST_Unevaluated)
  return;

// Evaluate the exception specification.
auto IES = computeImplicitExceptionSpec(*this, Loc, FD);
auto ESI = IES.getExceptionSpec();

// Update the type of the special member to use it.
UpdateExceptionSpec(FD, ESI);
7284}

7286void Sema::CheckExplicitlyDefaultedFunction(Scope *S, FunctionDecl *FD) {
assert(FD->isExplicitlyDefaulted() && "not explicitly-defaulted")((void)0);

DefaultedFunctionKind DefKind = getDefaultedFunctionKind(FD);
if (!DefKind) {
  assert(FD->getDeclContext()->isDependentContext())((void)0);
  return;
}

if (DefKind.isComparison())
  UnusedPrivateFields.clear();

if (DefKind.isSpecialMember()
        ? CheckExplicitlyDefaultedSpecialMember(cast<CXXMethodDecl>(FD),
                                                DefKind.asSpecialMember())
        : CheckExplicitlyDefaultedComparison(S, FD, DefKind.asComparison()))
  FD->setInvalidDecl();
7303}

7305bool Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
                                               CXXSpecialMember CSM) {
CXXRecordDecl *RD = MD->getParent();

assert(MD->isExplicitlyDefaulted() && CSM != CXXInvalid &&((void)0)
       "not an explicitly-defaulted special member")((void)0);

// Defer all checking for special members of a dependent type.
if (RD->isDependentType())
  return false;

// Whether this was the first-declared instance of the constructor.
// This affects whether we implicitly add an exception spec and constexpr.
bool First = MD == MD->getCanonicalDecl();

bool HadError = false;

// C++11 [dcl.fct.def.default]p1:
//   A function that is explicitly defaulted shall
//     -- be a special member function [...] (checked elsewhere),
//     -- have the same type (except for ref-qualifiers, and except that a
//        copy operation can take a non-const reference) as an implicit
//        declaration, and
//     -- not have default arguments.
// C++2a changes the second bullet to instead delete the function if it's
// defaulted on its first declaration, unless it's "an assignment operator,
// and its return type differs or its parameter type is not a reference".
bool DeleteOnTypeMismatch = getLangOpts().CPlusPlus20 && First;
bool ShouldDeleteForTypeMismatch = false;
unsigned ExpectedParams = 1;
if (CSM == CXXDefaultConstructor || CSM == CXXDestructor)
  ExpectedParams = 0;
if (MD->getNumParams() != ExpectedParams) {
  // This checks for default arguments: a copy or move constructor with a
  // default argument is classified as a default constructor, and assignment
  // operations and destructors can't have default arguments.
  Diag(MD->getLocation(), diag::err_defaulted_special_member_params)
    << CSM << MD->getSourceRange();
  HadError = true;
} else if (MD->isVariadic()) {
  if (DeleteOnTypeMismatch)
    ShouldDeleteForTypeMismatch = true;
  else {
    Diag(MD->getLocation(), diag::err_defaulted_special_member_variadic)
      << CSM << MD->getSourceRange();
    HadError = true;
  }
}

const FunctionProtoType *Type = MD->getType()->getAs<FunctionProtoType>();

bool CanHaveConstParam = false;
if (CSM == CXXCopyConstructor)
  CanHaveConstParam = RD->implicitCopyConstructorHasConstParam();
else if (CSM == CXXCopyAssignment)
  CanHaveConstParam = RD->implicitCopyAssignmentHasConstParam();

QualType ReturnType = Context.VoidTy;
if (CSM == CXXCopyAssignment || CSM == CXXMoveAssignment) {
  // Check for return type matching.
  ReturnType = Type->getReturnType();

  QualType DeclType = Context.getTypeDeclType(RD);
  DeclType = Context.getAddrSpaceQualType(DeclType, MD->getMethodQualifiers().getAddressSpace());
  QualType ExpectedReturnType = Context.getLValueReferenceType(DeclType);

  if (!Context.hasSameType(ReturnType, ExpectedReturnType)) {
    Diag(MD->getLocation(), diag::err_defaulted_special_member_return_type)
      << (CSM == CXXMoveAssignment) << ExpectedReturnType;
    HadError = true;
  }

  // A defaulted special member cannot have cv-qualifiers.
  if (Type->getMethodQuals().hasConst() || Type->getMethodQuals().hasVolatile()) {
    if (DeleteOnTypeMismatch)
      ShouldDeleteForTypeMismatch = true;
    else {
      Diag(MD->getLocation(), diag::err_defaulted_special_member_quals)
        << (CSM == CXXMoveAssignment) << getLangOpts().CPlusPlus14;
      HadError = true;
    }
  }
}

// Check for parameter type matching.
QualType ArgType = ExpectedParams ? Type->getParamType(0) : QualType();
bool HasConstParam = false;
if (ExpectedParams && ArgType->isReferenceType()) {
  // Argument must be reference to possibly-const T.
  QualType ReferentType = ArgType->getPointeeType();
  HasConstParam = ReferentType.isConstQualified();

  if (ReferentType.isVolatileQualified()) {
    if (DeleteOnTypeMismatch)
      ShouldDeleteForTypeMismatch = true;
    else {
      Diag(MD->getLocation(),
           diag::err_defaulted_special_member_volatile_param) << CSM;
      HadError = true;
    }
  }

  if (HasConstParam && !CanHaveConstParam) {
    if (DeleteOnTypeMismatch)
      ShouldDeleteForTypeMismatch = true;
    else if (CSM == CXXCopyConstructor || CSM == CXXCopyAssignment) {
      Diag(MD->getLocation(),
           diag::err_defaulted_special_member_copy_const_param)
        << (CSM == CXXCopyAssignment);
      // FIXME: Explain why this special member can't be const.
      HadError = true;
    } else {
      Diag(MD->getLocation(),
           diag::err_defaulted_special_member_move_const_param)
        << (CSM == CXXMoveAssignment);
      HadError = true;
    }
  }
} else if (ExpectedParams) {
  // A copy assignment operator can take its argument by value, but a
  // defaulted one cannot.
  assert(CSM == CXXCopyAssignment && "unexpected non-ref argument")((void)0);
  Diag(MD->getLocation(), diag::err_defaulted_copy_assign_not_ref);
  HadError = true;
}

// C++11 [dcl.fct.def.default]p2:
//   An explicitly-defaulted function may be declared constexpr only if it
//   would have been implicitly declared as constexpr,
// Do not apply this rule to members of class templates, since core issue 1358
// makes such functions always instantiate to constexpr functions. For
// functions which cannot be constexpr (for non-constructors in C++11 and for
// destructors in C++14 and C++17), this is checked elsewhere.
//
// FIXME: This should not apply if the member is deleted.
bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, RD, CSM,
                                                   HasConstParam);
if ((getLangOpts().CPlusPlus20 ||
     (getLangOpts().CPlusPlus14 ? !isa<CXXDestructorDecl>(MD)
                                : isa<CXXConstructorDecl>(MD))) &&
    MD->isConstexpr() && !Constexpr &&
    MD->getTemplatedKind() == FunctionDecl::TK_NonTemplate) {
  Diag(MD->getBeginLoc(), MD->isConsteval()
                              ? diag::err_incorrect_defaulted_consteval
                              : diag::err_incorrect_defaulted_constexpr)
      << CSM;
  // FIXME: Explain why the special member can't be constexpr.
  HadError = true;
}

if (First) {
  // C++2a [dcl.fct.def.default]p3:
  //   If a function is explicitly defaulted on its first declaration, it is
  //   implicitly considered to be constexpr if the implicit declaration
  //   would be.
  MD->setConstexprKind(Constexpr ? (MD->isConsteval()
                                        ? ConstexprSpecKind::Consteval
                                        : ConstexprSpecKind::Constexpr)
                                 : ConstexprSpecKind::Unspecified);

  if (!Type->hasExceptionSpec()) {
    // C++2a [except.spec]p3:
    //   If a declaration of a function does not have a noexcept-specifier
    //   [and] is defaulted on its first declaration, [...] the exception
    //   specification is as specified below
    FunctionProtoType::ExtProtoInfo EPI = Type->getExtProtoInfo();
    EPI.ExceptionSpec.Type = EST_Unevaluated;
    EPI.ExceptionSpec.SourceDecl = MD;
    MD->setType(Context.getFunctionType(ReturnType,
                                        llvm::makeArrayRef(&ArgType,
                                                           ExpectedParams),
                                        EPI));
  }
}

if (ShouldDeleteForTypeMismatch || ShouldDeleteSpecialMember(MD, CSM)) {
  if (First) {
    SetDeclDeleted(MD, MD->getLocation());
    if (!inTemplateInstantiation() && !HadError) {
      Diag(MD->getLocation(), diag::warn_defaulted_method_deleted) << CSM;
      if (ShouldDeleteForTypeMismatch) {
        Diag(MD->getLocation(), diag::note_deleted_type_mismatch) << CSM;
      } else {
        ShouldDeleteSpecialMember(MD, CSM, nullptr, /*Diagnose*/true);
      }
    }
    if (ShouldDeleteForTypeMismatch && !HadError) {
      Diag(MD->getLocation(),
           diag::warn_cxx17_compat_defaulted_method_type_mismatch) << CSM;
    }
  } else {
    // C++11 [dcl.fct.def.default]p4:
    //   [For a] user-provided explicitly-defaulted function [...] if such a
    //   function is implicitly defined as deleted, the program is ill-formed.
    Diag(MD->getLocation(), diag::err_out_of_line_default_deletes) << CSM;
    assert(!ShouldDeleteForTypeMismatch && "deleted non-first decl")((void)0);
    ShouldDeleteSpecialMember(MD, CSM, nullptr, /*Diagnose*/true);
    HadError = true;
  }
}

return HadError;
7507}

7509namespace {
7510/// Helper class for building and checking a defaulted comparison.
7511///
7512/// Defaulted functions are built in two phases:
7513///
7514///  * First, the set of operations that the function will perform are
7515///    identified, and some of them are checked. If any of the checked
7516///    operations is invalid in certain ways, the comparison function is
7517///    defined as deleted and no body is built.
7518///  * Then, if the function is not defined as deleted, the body is built.
7519///
7520/// This is accomplished by performing two visitation steps over the eventual
7521/// body of the function.
7522template<typename Derived, typename ResultList, typename Result,
       typename Subobject>
7524class DefaultedComparisonVisitor {
7525public:
using DefaultedComparisonKind = Sema::DefaultedComparisonKind;

DefaultedComparisonVisitor(Sema &S, CXXRecordDecl *RD, FunctionDecl *FD,
                           DefaultedComparisonKind DCK)
    : S(S), RD(RD), FD(FD), DCK(DCK) {
  if (auto *Info = FD->getDefaultedFunctionInfo()) {
    // FIXME: Change CreateOverloadedBinOp to take an ArrayRef instead of an
    // UnresolvedSet to avoid this copy.
    Fns.assign(Info->getUnqualifiedLookups().begin(),
               Info->getUnqualifiedLookups().end());
  }
}

ResultList visit() {
  // The type of an lvalue naming a parameter of this function.
  QualType ParamLvalType =
      FD->getParamDecl(0)->getType().getNonReferenceType();

  ResultList Results;

  switch (DCK) {
  case DefaultedComparisonKind::None:
    llvm_unreachable("not a defaulted comparison")__builtin_unreachable();

  case DefaultedComparisonKind::Equal:
  case DefaultedComparisonKind::ThreeWay:
    getDerived().visitSubobjects(Results, RD, ParamLvalType.getQualifiers());
    return Results;

  case DefaultedComparisonKind::NotEqual:
  case DefaultedComparisonKind::Relational:
    Results.add(getDerived().visitExpandedSubobject(
        ParamLvalType, getDerived().getCompleteObject()));
    return Results;
  }
  llvm_unreachable("")__builtin_unreachable();
}

7564protected:
Derived &getDerived() { return static_cast<Derived&>(*this); }

/// Visit the expanded list of subobjects of the given type, as specified in
/// C++2a [class.compare.default].
///
/// \return \c true if the ResultList object said we're done, \c false if not.
bool visitSubobjects(ResultList &Results, CXXRecordDecl *Record,
                     Qualifiers Quals) {
  // C++2a [class.compare.default]p4:
  //   The direct base class subobjects of C
  for (CXXBaseSpecifier &Base : Record->bases())
    if (Results.add(getDerived().visitSubobject(
            S.Context.getQualifiedType(Base.getType(), Quals),
            getDerived().getBase(&Base))))
      return true;

  //   followed by the non-static data members of C
  for (FieldDecl *Field : Record->fields()) {
    // Recursively expand anonymous structs.
    if (Field->isAnonymousStructOrUnion()) {
      if (visitSubobjects(Results, Field->getType()->getAsCXXRecordDecl(),
                          Quals))
        return true;
      continue;
    }

    // Figure out the type of an lvalue denoting this field.
    Qualifiers FieldQuals = Quals;
    if (Field->isMutable())
      FieldQuals.removeConst();
    QualType FieldType =
        S.Context.getQualifiedType(Field->getType(), FieldQuals);

    if (Results.add(getDerived().visitSubobject(
            FieldType, getDerived().getField(Field))))
      return true;
  }

  //   form a list of subobjects.
  return false;
}

Result visitSubobject(QualType Type, Subobject Subobj) {
  //   In that list, any subobject of array type is recursively expanded
  const ArrayType *AT = S.Context.getAsArrayType(Type);
  if (auto *CAT = dyn_cast_or_null<ConstantArrayType>(AT))
    return getDerived().visitSubobjectArray(CAT->getElementType(),
                                            CAT->getSize(), Subobj);
  return getDerived().visitExpandedSubobject(Type, Subobj);
}

Result visitSubobjectArray(QualType Type, const llvm::APInt &Size,
                           Subobject Subobj) {
  return getDerived().visitSubobject(Type, Subobj);
}

7621protected:
Sema &S;
CXXRecordDecl *RD;
FunctionDecl *FD;
DefaultedComparisonKind DCK;
UnresolvedSet<16> Fns;
7627};

7629/// Information about a defaulted comparison, as determined by
7630/// DefaultedComparisonAnalyzer.
7631struct DefaultedComparisonInfo {
bool Deleted = false;
bool Constexpr = true;
ComparisonCategoryType Category = ComparisonCategoryType::StrongOrdering;

static DefaultedComparisonInfo deleted() {
  DefaultedComparisonInfo Deleted;
  Deleted.Deleted = true;
  return Deleted;
}

bool add(const DefaultedComparisonInfo &R) {
  Deleted |= R.Deleted;
  Constexpr &= R.Constexpr;
  Category = commonComparisonType(Category, R.Category);
  return Deleted;
}
7648};

7650/// An element in the expanded list of subobjects of a defaulted comparison, as
7651/// specified in C++2a [class.compare.default]p4.
7652struct DefaultedComparisonSubobject {
enum { CompleteObject, Member, Base } Kind;
NamedDecl *Decl;
SourceLocation Loc;
7656};

7658/// A visitor over the notional body of a defaulted comparison that determines
7659/// whether that body would be deleted or constexpr.
7660class DefaultedComparisonAnalyzer
  : public DefaultedComparisonVisitor<DefaultedComparisonAnalyzer,
                                      DefaultedComparisonInfo,
                                      DefaultedComparisonInfo,
                                      DefaultedComparisonSubobject> {
7665public:
enum DiagnosticKind { NoDiagnostics, ExplainDeleted, ExplainConstexpr };

7668private:
DiagnosticKind Diagnose;

7671public:
using Base = DefaultedComparisonVisitor;
using Result = DefaultedComparisonInfo;
using Subobject = DefaultedComparisonSubobject;

friend Base;

DefaultedComparisonAnalyzer(Sema &S, CXXRecordDecl *RD, FunctionDecl *FD,
                            DefaultedComparisonKind DCK,
                            DiagnosticKind Diagnose = NoDiagnostics)
    : Base(S, RD, FD, DCK), Diagnose(Diagnose) {}

Result visit() {
  if ((DCK == DefaultedComparisonKind::Equal ||
       DCK == DefaultedComparisonKind::ThreeWay) &&
      RD->hasVariantMembers()) {
    // C++2a [class.compare.default]p2 [P2002R0]:
    //   A defaulted comparison operator function for class C is defined as
    //   deleted if [...] C has variant members.
    if (Diagnose == ExplainDeleted) {
      S.Diag(FD->getLocation(), diag::note_defaulted_comparison_union)
        << FD << RD->isUnion() << RD;
    }
    return Result::deleted();
  }

  return Base::visit();
}

7700private:
Subobject getCompleteObject() {
  return Subobject{Subobject::CompleteObject, RD, FD->getLocation()};
}

Subobject getBase(CXXBaseSpecifier *Base) {
  return Subobject{Subobject::Base, Base->getType()->getAsCXXRecordDecl(),
                   Base->getBaseTypeLoc()};
}

Subobject getField(FieldDecl *Field) {
  return Subobject{Subobject::Member, Field, Field->getLocation()};
}

Result visitExpandedSubobject(QualType Type, Subobject Subobj) {
  // C++2a [class.compare.default]p2 [P2002R0]:
  //   A defaulted <=> or == operator function for class C is defined as
  //   deleted if any non-static data member of C is of reference type
  if (Type->isReferenceType()) {
    if (Diagnose == ExplainDeleted) {
      S.Diag(Subobj.Loc, diag::note_defaulted_comparison_reference_member)
          << FD << RD;
    }
    return Result::deleted();
  }

  // [...] Let xi be an lvalue denoting the ith element [...]
  OpaqueValueExpr Xi(FD->getLocation(), Type, VK_LValue);
  Expr *Args[] = {&Xi, &Xi};

  // All operators start by trying to apply that same operator recursively.
  OverloadedOperatorKind OO = FD->getOverloadedOperator();
  assert(OO != OO_None && "not an overloaded operator!")((void)0);
  return visitBinaryOperator(OO, Args, Subobj);
}

Result
visitBinaryOperator(OverloadedOperatorKind OO, ArrayRef<Expr *> Args,
                    Subobject Subobj,
                    OverloadCandidateSet *SpaceshipCandidates = nullptr) {
  // Note that there is no need to consider rewritten candidates here if
  // we've already found there is no viable 'operator<=>' candidate (and are
  // considering synthesizing a '<=>' from '==' and '<').
  OverloadCandidateSet CandidateSet(
      FD->getLocation(), OverloadCandidateSet::CSK_Operator,
      OverloadCandidateSet::OperatorRewriteInfo(
          OO, /*AllowRewrittenCandidates=*/!SpaceshipCandidates));

  /// C++2a [class.compare.default]p1 [P2002R0]:
  ///   [...] the defaulted function itself is never a candidate for overload
  ///   resolution [...]
  CandidateSet.exclude(FD);

  if (Args[0]->getType()->isOverloadableType())
    S.LookupOverloadedBinOp(CandidateSet, OO, Fns, Args);
  else
    // FIXME: We determine whether this is a valid expression by checking to
    // see if there's a viable builtin operator candidate for it. That isn't
    // really what the rules ask us to do, but should give the right results.
    S.AddBuiltinOperatorCandidates(OO, FD->getLocation(), Args, CandidateSet);

  Result R;

  OverloadCandidateSet::iterator Best;
  switch (CandidateSet.BestViableFunction(S, FD->getLocation(), Best)) {
  case OR_Success: {
    // C++2a [class.compare.secondary]p2 [P2002R0]:
    //   The operator function [...] is defined as deleted if [...] the
    //   candidate selected by overload resolution is not a rewritten
    //   candidate.
    if ((DCK == DefaultedComparisonKind::NotEqual ||
         DCK == DefaultedComparisonKind::Relational) &&
        !Best->RewriteKind) {
      if (Diagnose == ExplainDeleted) {
        S.Diag(Best->Function->getLocation(),
               diag::note_defaulted_comparison_not_rewritten_callee)
            << FD;
      }
      return Result::deleted();
    }

    // Throughout C++2a [class.compare]: if overload resolution does not
    // result in a usable function, the candidate function is defined as
    // deleted. This requires that we selected an accessible function.
    //
    // Note that this only considers the access of the function when named
    // within the type of the subobject, and not the access path for any
    // derived-to-base conversion.
    CXXRecordDecl *ArgClass = Args[0]->getType()->getAsCXXRecordDecl();
    if (ArgClass && Best->FoundDecl.getDecl() &&
        Best->FoundDecl.getDecl()->isCXXClassMember()) {
      QualType ObjectType = Subobj.Kind == Subobject::Member
                                ? Args[0]->getType()
                                : S.Context.getRecordType(RD);
      if (!S.isMemberAccessibleForDeletion(
              ArgClass, Best->FoundDecl, ObjectType, Subobj.Loc,
              Diagnose == ExplainDeleted
                  ? S.PDiag(diag::note_defaulted_comparison_inaccessible)
                        << FD << Subobj.Kind << Subobj.Decl
                  : S.PDiag()))
        return Result::deleted();
    }

    bool NeedsDeducing =
        OO == OO_Spaceship && FD->getReturnType()->isUndeducedAutoType();

    if (FunctionDecl *BestFD = Best->Function) {
      // C++2a [class.compare.default]p3 [P2002R0]:
      //   A defaulted comparison function is constexpr-compatible if
      //   [...] no overlod resolution performed [...] results in a
      //   non-constexpr function.
      assert(!BestFD->isDeleted() && "wrong overload resolution result")((void)0);
      // If it's not constexpr, explain why not.
      if (Diagnose == ExplainConstexpr && !BestFD->isConstexpr()) {
        if (Subobj.Kind != Subobject::CompleteObject)
          S.Diag(Subobj.Loc, diag::note_defaulted_comparison_not_constexpr)
            << Subobj.Kind << Subobj.Decl;
        S.Diag(BestFD->getLocation(),
               diag::note_defaulted_comparison_not_constexpr_here);
        // Bail out after explaining; we don't want any more notes.
        return Result::deleted();
      }
      R.Constexpr &= BestFD->isConstexpr();

      if (NeedsDeducing) {
        // If any callee has an undeduced return type, deduce it now.
        // FIXME: It's not clear how a failure here should be handled. For
        // now, we produce an eager diagnostic, because that is forward
        // compatible with most (all?) other reasonable options.
        if (BestFD->getReturnType()->isUndeducedType() &&
            S.DeduceReturnType(BestFD, FD->getLocation(),
                               /*Diagnose=*/false)) {
          // Don't produce a duplicate error when asked to explain why the
          // comparison is deleted: we diagnosed that when initially checking
          // the defaulted operator.
          if (Diagnose == NoDiagnostics) {
            S.Diag(
                FD->getLocation(),
                diag::err_defaulted_comparison_cannot_deduce_undeduced_auto)
                << Subobj.Kind << Subobj.Decl;
            S.Diag(
                Subobj.Loc,
                diag::note_defaulted_comparison_cannot_deduce_undeduced_auto)
                << Subobj.Kind << Subobj.Decl;
            S.Diag(BestFD->getLocation(),
                   diag::note_defaulted_comparison_cannot_deduce_callee)
                << Subobj.Kind << Subobj.Decl;
          }
          return Result::deleted();
        }
        auto *Info = S.Context.CompCategories.lookupInfoForType(
            BestFD->getCallResultType());
        if (!Info) {
          if (Diagnose == ExplainDeleted) {
            S.Diag(Subobj.Loc, diag::note_defaulted_comparison_cannot_deduce)
                << Subobj.Kind << Subobj.Decl
                << BestFD->getCallResultType().withoutLocalFastQualifiers();
            S.Diag(BestFD->getLocation(),
                   diag::note_defaulted_comparison_cannot_deduce_callee)
                << Subobj.Kind << Subobj.Decl;
          }
          return Result::deleted();
        }
        R.Category = Info->Kind;
      }
    } else {
      QualType T = Best->BuiltinParamTypes[0];
      assert(T == Best->BuiltinParamTypes[1] &&((void)0)
             "builtin comparison for different types?")((void)0);
      assert(Best->BuiltinParamTypes[2].isNull() &&((void)0)
             "invalid builtin comparison")((void)0);

      if (NeedsDeducing) {
        Optional<ComparisonCategoryType> Cat =
            getComparisonCategoryForBuiltinCmp(T);
        assert(Cat && "no category for builtin comparison?")((void)0);
        R.Category = *Cat;
      }
    }

    // Note that we might be rewriting to a different operator. That call is
    // not considered until we come to actually build the comparison function.
    break;
  }

  case OR_Ambiguous:
    if (Diagnose == ExplainDeleted) {
      unsigned Kind = 0;
      if (FD->getOverloadedOperator() == OO_Spaceship && OO != OO_Spaceship)
        Kind = OO == OO_EqualEqual ? 1 : 2;
      CandidateSet.NoteCandidates(
          PartialDiagnosticAt(
              Subobj.Loc, S.PDiag(diag::note_defaulted_comparison_ambiguous)
                              << FD << Kind << Subobj.Kind << Subobj.Decl),
          S, OCD_AmbiguousCandidates, Args);
    }
    R = Result::deleted();
    break;

  case OR_Deleted:
    if (Diagnose == ExplainDeleted) {
      if ((DCK == DefaultedComparisonKind::NotEqual ||
           DCK == DefaultedComparisonKind::Relational) &&
          !Best->RewriteKind) {
        S.Diag(Best->Function->getLocation(),
               diag::note_defaulted_comparison_not_rewritten_callee)
            << FD;
      } else {
        S.Diag(Subobj.Loc,
               diag::note_defaulted_comparison_calls_deleted)
            << FD << Subobj.Kind << Subobj.Decl;
        S.NoteDeletedFunction(Best->Function);
      }
    }
    R = Result::deleted();
    break;

  case OR_No_Viable_Function:
    // If there's no usable candidate, we're done unless we can rewrite a
    // '<=>' in terms of '==' and '<'.
    if (OO == OO_Spaceship &&
        S.Context.CompCategories.lookupInfoForType(FD->getReturnType())) {
      // For any kind of comparison category return type, we need a usable
      // '==' and a usable '<'.
      if (!R.add(visitBinaryOperator(OO_EqualEqual, Args, Subobj,
                                     &CandidateSet)))
        R.add(visitBinaryOperator(OO_Less, Args, Subobj, &CandidateSet));
      break;
    }

    if (Diagnose == ExplainDeleted) {
      S.Diag(Subobj.Loc, diag::note_defaulted_comparison_no_viable_function)
          << FD << Subobj.Kind << Subobj.Decl;

      // For a three-way comparison, list both the candidates for the
      // original operator and the candidates for the synthesized operator.
      if (SpaceshipCandidates) {
        SpaceshipCandidates->NoteCandidates(
            S, Args,
            SpaceshipCandidates->CompleteCandidates(S, OCD_AllCandidates,
                                                    Args, FD->getLocation()));
        S.Diag(Subobj.Loc,
               diag::note_defaulted_comparison_no_viable_function_synthesized)
            << (OO == OO_EqualEqual ? 0 : 1);
      }

      CandidateSet.NoteCandidates(
          S, Args,
          CandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args,
                                          FD->getLocation()));
    }
    R = Result::deleted();
    break;
  }

  return R;
}
7957};

7959/// A list of statements.
7960struct StmtListResult {
bool IsInvalid = false;
llvm::SmallVector<Stmt*, 16> Stmts;

bool add(const StmtResult &S) {
  IsInvalid |= S.isInvalid();
  if (IsInvalid)
    return true;
  Stmts.push_back(S.get());
  return false;
}
7971};

7973/// A visitor over the notional body of a defaulted comparison that synthesizes
7974/// the actual body.
7975class DefaultedComparisonSynthesizer
  : public DefaultedComparisonVisitor<DefaultedComparisonSynthesizer,
                                      StmtListResult, StmtResult,
                                      std::pair<ExprResult, ExprResult>> {
SourceLocation Loc;
unsigned ArrayDepth = 0;

7982public:
using Base = DefaultedComparisonVisitor;
using ExprPair = std::pair<ExprResult, ExprResult>;

friend Base;

DefaultedComparisonSynthesizer(Sema &S, CXXRecordDecl *RD, FunctionDecl *FD,
                               DefaultedComparisonKind DCK,
                               SourceLocation BodyLoc)
    : Base(S, RD, FD, DCK), Loc(BodyLoc) {}

/// Build a suitable function body for this defaulted comparison operator.
StmtResult build() {
  Sema::CompoundScopeRAII CompoundScope(S);

  StmtListResult Stmts = visit();
  if (Stmts.IsInvalid)
    return StmtError();

  ExprResult RetVal;
  switch (DCK) {
  case DefaultedComparisonKind::None:
    llvm_unreachable("not a defaulted comparison")__builtin_unreachable();

  case DefaultedComparisonKind::Equal: {
    // C++2a [class.eq]p3:
    //   [...] compar[e] the corresponding elements [...] until the first
    //   index i where xi == yi yields [...] false. If no such index exists,
    //   V is true. Otherwise, V is false.
    //
    // Join the comparisons with '&&'s and return the result. Use a right
    // fold (traversing the conditions right-to-left), because that
    // short-circuits more naturally.
    auto OldStmts = std::move(Stmts.Stmts);
    Stmts.Stmts.clear();
    ExprResult CmpSoFar;
    // Finish a particular comparison chain.
    auto FinishCmp = [&] {
      if (Expr *Prior = CmpSoFar.get()) {
        // Convert the last expression to 'return ...;'
        if (RetVal.isUnset() && Stmts.Stmts.empty())
          RetVal = CmpSoFar;
        // Convert any prior comparison to 'if (!(...)) return false;'
        else if (Stmts.add(buildIfNotCondReturnFalse(Prior)))
          return true;
        CmpSoFar = ExprResult();
      }
      return false;
    };
    for (Stmt *EAsStmt : llvm::reverse(OldStmts)) {
      Expr *E = dyn_cast<Expr>(EAsStmt);
      if (!E) {
        // Found an array comparison.
        if (FinishCmp() || Stmts.add(EAsStmt))
          return StmtError();
        continue;
      }

      if (CmpSoFar.isUnset()) {
        CmpSoFar = E;
        continue;
      }
      CmpSoFar = S.CreateBuiltinBinOp(Loc, BO_LAnd, E, CmpSoFar.get());
      if (CmpSoFar.isInvalid())
        return StmtError();
    }
    if (FinishCmp())
      return StmtError();
    std::reverse(Stmts.Stmts.begin(), Stmts.Stmts.end());
    //   If no such index exists, V is true.
    if (RetVal.isUnset())
      RetVal = S.ActOnCXXBoolLiteral(Loc, tok::kw_true);
    break;
  }

  case DefaultedComparisonKind::ThreeWay: {
    // Per C++2a [class.spaceship]p3, as a fallback add:
    // return static_cast<R>(std::strong_ordering::equal);
    QualType StrongOrdering = S.CheckComparisonCategoryType(
        ComparisonCategoryType::StrongOrdering, Loc,
        Sema::ComparisonCategoryUsage::DefaultedOperator);
    if (StrongOrdering.isNull())
      return StmtError();
    VarDecl *EqualVD = S.Context.CompCategories.getInfoForType(StrongOrdering)
                           .getValueInfo(ComparisonCategoryResult::Equal)
                           ->VD;
    RetVal = getDecl(EqualVD);
    if (RetVal.isInvalid())
      return StmtError();
    RetVal = buildStaticCastToR(RetVal.get());
    break;
  }

  case DefaultedComparisonKind::NotEqual:
  case DefaultedComparisonKind::Relational:
    RetVal = cast<Expr>(Stmts.Stmts.pop_back_val());
    break;
  }

  // Build the final return statement.
  if (RetVal.isInvalid())
    return StmtError();
  StmtResult ReturnStmt = S.BuildReturnStmt(Loc, RetVal.get());
  if (ReturnStmt.isInvalid())
    return StmtError();
  Stmts.Stmts.push_back(ReturnStmt.get());

  return S.ActOnCompoundStmt(Loc, Loc, Stmts.Stmts, /*IsStmtExpr=*/false);
}

8092private:
ExprResult getDecl(ValueDecl *VD) {
  return S.BuildDeclarationNameExpr(
      CXXScopeSpec(), DeclarationNameInfo(VD->getDeclName(), Loc), VD);
}

ExprResult getParam(unsigned I) {
  ParmVarDecl *PD = FD->getParamDecl(I);
  return getDecl(PD);
}

ExprPair getCompleteObject() {
  unsigned Param = 0;
  ExprResult LHS;
  if (isa<CXXMethodDecl>(FD)) {
    // LHS is '*this'.
    LHS = S.ActOnCXXThis(Loc);
    if (!LHS.isInvalid())
      LHS = S.CreateBuiltinUnaryOp(Loc, UO_Deref, LHS.get());
  } else {
    LHS = getParam(Param++);
  }
  ExprResult RHS = getParam(Param++);
  assert(Param == FD->getNumParams())((void)0);
  return {LHS, RHS};
}

ExprPair getBase(CXXBaseSpecifier *Base) {
  ExprPair Obj = getCompleteObject();
  if (Obj.first.isInvalid() || Obj.second.isInvalid())
    return {ExprError(), ExprError()};
  CXXCastPath Path = {Base};
  return {S.ImpCastExprToType(Obj.first.get(), Base->getType(),
                              CK_DerivedToBase, VK_LValue, &Path),
          S.ImpCastExprToType(Obj.second.get(), Base->getType(),
                              CK_DerivedToBase, VK_LValue, &Path)};
}

ExprPair getField(FieldDecl *Field) {
  ExprPair Obj = getCompleteObject();
  if (Obj.first.isInvalid() || Obj.second.isInvalid())
    return {ExprError(), ExprError()};

  DeclAccessPair Found = DeclAccessPair::make(Field, Field->getAccess());
  DeclarationNameInfo NameInfo(Field->getDeclName(), Loc);
  return {S.BuildFieldReferenceExpr(Obj.first.get(), /*IsArrow=*/false, Loc,
                                    CXXScopeSpec(), Field, Found, NameInfo),
          S.BuildFieldReferenceExpr(Obj.second.get(), /*IsArrow=*/false, Loc,
                                    CXXScopeSpec(), Field, Found, NameInfo)};
}

// FIXME: When expanding a subobject, register a note in the code synthesis
// stack to say which subobject we're comparing.

StmtResult buildIfNotCondReturnFalse(ExprResult Cond) {
  if (Cond.isInvalid())
    return StmtError();

  ExprResult NotCond = S.CreateBuiltinUnaryOp(Loc, UO_LNot, Cond.get());
  if (NotCond.isInvalid())
    return StmtError();

  ExprResult False = S.ActOnCXXBoolLiteral(Loc, tok::kw_false);
  assert(!False.isInvalid() && "should never fail")((void)0);
  StmtResult ReturnFalse = S.BuildReturnStmt(Loc, False.get());
  if (ReturnFalse.isInvalid())
    return StmtError();

  return S.ActOnIfStmt(Loc, false, Loc, nullptr,
                       S.ActOnCondition(nullptr, Loc, NotCond.get(),
                                        Sema::ConditionKind::Boolean),
                       Loc, ReturnFalse.get(), SourceLocation(), nullptr);
}

StmtResult visitSubobjectArray(QualType Type, llvm::APInt Size,
                               ExprPair Subobj) {
  QualType SizeType = S.Context.getSizeType();
  Size = Size.zextOrTrunc(S.Context.getTypeSize(SizeType));

  // Build 'size_t i$n = 0'.
  IdentifierInfo *IterationVarName = nullptr;
  {
    SmallString<8> Str;
    llvm::raw_svector_ostream OS(Str);
    OS << "i" << ArrayDepth;
    IterationVarName = &S.Context.Idents.get(OS.str());
  }
  VarDecl *IterationVar = VarDecl::Create(
      S.Context, S.CurContext, Loc, Loc, IterationVarName, SizeType,
      S.Context.getTrivialTypeSourceInfo(SizeType, Loc), SC_None);
  llvm::APInt Zero(S.Context.getTypeSize(SizeType), 0);
  IterationVar->setInit(
      IntegerLiteral::Create(S.Context, Zero, SizeType, Loc));
  Stmt *Init = new (S.Context) DeclStmt(DeclGroupRef(IterationVar), Loc, Loc);

  auto IterRef = [&] {
    ExprResult Ref = S.BuildDeclarationNameExpr(
        CXXScopeSpec(), DeclarationNameInfo(IterationVarName, Loc),
        IterationVar);
    assert(!Ref.isInvalid() && "can't reference our own variable?")((void)0);
    return Ref.get();
  };

  // Build 'i$n != Size'.
  ExprResult Cond = S.CreateBuiltinBinOp(
      Loc, BO_NE, IterRef(),
      IntegerLiteral::Create(S.Context, Size, SizeType, Loc));
  assert(!Cond.isInvalid() && "should never fail")((void)0);

  // Build '++i$n'.
  ExprResult Inc = S.CreateBuiltinUnaryOp(Loc, UO_PreInc, IterRef());
  assert(!Inc.isInvalid() && "should never fail")((void)0);

  // Build 'a[i$n]' and 'b[i$n]'.
  auto Index = [&](ExprResult E) {
    if (E.isInvalid())
      return ExprError();
    return S.CreateBuiltinArraySubscriptExpr(E.get(), Loc, IterRef(), Loc);
  };
  Subobj.first = Index(Subobj.first);
  Subobj.second = Index(Subobj.second);

  // Compare the array elements.
  ++ArrayDepth;
  StmtResult Substmt = visitSubobject(Type, Subobj);
  --ArrayDepth;

  if (Substmt.isInvalid())
    return StmtError();

  // For the inner level of an 'operator==', build 'if (!cmp) return false;'.
  // For outer levels or for an 'operator<=>' we already have a suitable
  // statement that returns as necessary.
  if (Expr *ElemCmp = dyn_cast<Expr>(Substmt.get())) {
    assert(DCK == DefaultedComparisonKind::Equal &&((void)0)
           "should have non-expression statement")((void)0);
    Substmt = buildIfNotCondReturnFalse(ElemCmp);
    if (Substmt.isInvalid())
      return StmtError();
  }

  // Build 'for (...) ...'
  return S.ActOnForStmt(Loc, Loc, Init,
                        S.ActOnCondition(nullptr, Loc, Cond.get(),
                                         Sema::ConditionKind::Boolean),
                        S.MakeFullDiscardedValueExpr(Inc.get()), Loc,
                        Substmt.get());
}

StmtResult visitExpandedSubobject(QualType Type, ExprPair Obj) {
  if (Obj.first.isInvalid() || Obj.second.isInvalid())
    return StmtError();

  OverloadedOperatorKind OO = FD->getOverloadedOperator();
  BinaryOperatorKind Opc = BinaryOperator::getOverloadedOpcode(OO);
  ExprResult Op;
  if (Type->isOverloadableType())
    Op = S.CreateOverloadedBinOp(Loc, Opc, Fns, Obj.first.get(),
                                 Obj.second.get(), /*PerformADL=*/true,
                                 /*AllowRewrittenCandidates=*/true, FD);
  else
    Op = S.CreateBuiltinBinOp(Loc, Opc, Obj.first.get(), Obj.second.get());
  if (Op.isInvalid())
    return StmtError();

  switch (DCK) {
  case DefaultedComparisonKind::None:
    llvm_unreachable("not a defaulted comparison")__builtin_unreachable();

  case DefaultedComparisonKind::Equal:
    // Per C++2a [class.eq]p2, each comparison is individually contextually
    // converted to bool.
    Op = S.PerformContextuallyConvertToBool(Op.get());
    if (Op.isInvalid())
      return StmtError();
    return Op.get();

  case DefaultedComparisonKind::ThreeWay: {
    // Per C++2a [class.spaceship]p3, form:
    //   if (R cmp = static_cast<R>(op); cmp != 0)
    //     return cmp;
    QualType R = FD->getReturnType();
    Op = buildStaticCastToR(Op.get());
    if (Op.isInvalid())
      return StmtError();

    // R cmp = ...;
    IdentifierInfo *Name = &S.Context.Idents.get("cmp");
    VarDecl *VD =
        VarDecl::Create(S.Context, S.CurContext, Loc, Loc, Name, R,
                        S.Context.getTrivialTypeSourceInfo(R, Loc), SC_None);
    S.AddInitializerToDecl(VD, Op.get(), /*DirectInit=*/false);
    Stmt *InitStmt = new (S.Context) DeclStmt(DeclGroupRef(VD), Loc, Loc);

    // cmp != 0
    ExprResult VDRef = getDecl(VD);
    if (VDRef.isInvalid())
      return StmtError();
    llvm::APInt ZeroVal(S.Context.getIntWidth(S.Context.IntTy), 0);
    Expr *Zero =
        IntegerLiteral::Create(S.Context, ZeroVal, S.Context.IntTy, Loc);
    ExprResult Comp;
    if (VDRef.get()->getType()->isOverloadableType())
      Comp = S.CreateOverloadedBinOp(Loc, BO_NE, Fns, VDRef.get(), Zero, true,
                                     true, FD);
    else
      Comp = S.CreateBuiltinBinOp(Loc, BO_NE, VDRef.get(), Zero);
    if (Comp.isInvalid())
      return StmtError();
    Sema::ConditionResult Cond = S.ActOnCondition(
        nullptr, Loc, Comp.get(), Sema::ConditionKind::Boolean);
    if (Cond.isInvalid())
      return StmtError();

    // return cmp;
    VDRef = getDecl(VD);
    if (VDRef.isInvalid())
      return StmtError();
    StmtResult ReturnStmt = S.BuildReturnStmt(Loc, VDRef.get());
    if (ReturnStmt.isInvalid())
      return StmtError();

    // if (...)
    return S.ActOnIfStmt(Loc, /*IsConstexpr=*/false, Loc, InitStmt, Cond, Loc,
                         ReturnStmt.get(),
                         /*ElseLoc=*/SourceLocation(), /*Else=*/nullptr);
  }

  case DefaultedComparisonKind::NotEqual:
  case DefaultedComparisonKind::Relational:
    // C++2a [class.compare.secondary]p2:
    //   Otherwise, the operator function yields x @ y.
    return Op.get();
  }
  llvm_unreachable("")__builtin_unreachable();
}

/// Build "static_cast<R>(E)".
ExprResult buildStaticCastToR(Expr *E) {
  QualType R = FD->getReturnType();
  assert(!R->isUndeducedType() && "type should have been deduced already")((void)0);

  // Don't bother forming a no-op cast in the common case.
  if (E->isPRValue() && S.Context.hasSameType(E->getType(), R))
    return E;
  return S.BuildCXXNamedCast(Loc, tok::kw_static_cast,
                             S.Context.getTrivialTypeSourceInfo(R, Loc), E,
                             SourceRange(Loc, Loc), SourceRange(Loc, Loc));
}
8341};
8342}

8344/// Perform the unqualified lookups that might be needed to form a defaulted
8345/// comparison function for the given operator.
8346static void lookupOperatorsForDefaultedComparison(Sema &Self, Scope *S,
                                                UnresolvedSetImpl &Operators,
                                                OverloadedOperatorKind Op) {
auto Lookup = [&](OverloadedOperatorKind OO) {
  Self.LookupOverloadedOperatorName(OO, S, Operators);
};

// Every defaulted operator looks up itself.
Lookup(Op);
// ... and the rewritten form of itself, if any.
if (OverloadedOperatorKind ExtraOp = getRewrittenOverloadedOperator(Op))
  Lookup(ExtraOp);

// For 'operator<=>', we also form a 'cmp != 0' expression, and might
// synthesize a three-way comparison from '<' and '=='. In a dependent
// context, we also need to look up '==' in case we implicitly declare a
// defaulted 'operator=='.
if (Op == OO_Spaceship) {
  Lookup(OO_ExclaimEqual);
  Lookup(OO_Less);
  Lookup(OO_EqualEqual);
}
8368}

8370bool Sema::CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *FD,
                                            DefaultedComparisonKind DCK) {
assert(DCK != DefaultedComparisonKind::None && "not a defaulted comparison")((void)0);

CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(FD->getLexicalDeclContext());
1
Assuming the object is not a 'CXXRecordDecl'→
2
←
'RD' initialized to a null pointer value→
assert(RD && "defaulted comparison is not defaulted in a class")((void)0);

// Perform any unqualified lookups we're going to need to default this
// function.
if (S) {
3
←
Assuming 'S' is null→
4
←
Taking false branch→
  UnresolvedSet<32> Operators;
  lookupOperatorsForDefaultedComparison(*this, S, Operators,
                                        FD->getOverloadedOperator());
  FD->setDefaultedFunctionInfo(FunctionDecl::DefaultedFunctionInfo::Create(
      Context, Operators.pairs()));
}

// C++2a [class.compare.default]p1:
//   A defaulted comparison operator function for some class C shall be a
//   non-template function declared in the member-specification of C that is
//    -- a non-static const member of C having one parameter of type
//       const C&, or
//    -- a friend of C having two parameters of type const C& or two
//       parameters of type C.
QualType ExpectedParmType1 = Context.getRecordType(RD);
QualType ExpectedParmType2 =
    Context.getLValueReferenceType(ExpectedParmType1.withConst());
if (isa<CXXMethodDecl>(FD))
5
←
Assuming 'FD' is not a 'CXXMethodDecl'→
6
←
Taking false branch→
  ExpectedParmType1 = ExpectedParmType2;
for (const ParmVarDecl *Param : FD->parameters()) {
7
←
Assuming '__begin1' is equal to '__end1'→
  if (!Param->getType()->isDependentType() &&
      !Context.hasSameType(Param->getType(), ExpectedParmType1) &&
      !Context.hasSameType(Param->getType(), ExpectedParmType2)) {
    // Don't diagnose an implicit 'operator=='; we will have diagnosed the
    // corresponding defaulted 'operator<=>' already.
    if (!FD->isImplicit()) {
      Diag(FD->getLocation(), diag::err_defaulted_comparison_param)
          << (int)DCK << Param->getType() << ExpectedParmType1
          << !isa<CXXMethodDecl>(FD)
          << ExpectedParmType2 << Param->getSourceRange();
    }
    return true;
  }
}
if (FD->getNumParams() == 2 &&
8
←
Assuming the condition is false→
9
←
Taking false branch→
    !Context.hasSameType(FD->getParamDecl(0)->getType(),
                         FD->getParamDecl(1)->getType())) {
  if (!FD->isImplicit()) {
    Diag(FD->getLocation(), diag::err_defaulted_comparison_param_mismatch)
        << (int)DCK
        << FD->getParamDecl(0)->getType()
        << FD->getParamDecl(0)->getSourceRange()
        << FD->getParamDecl(1)->getType()
        << FD->getParamDecl(1)->getSourceRange();
  }
  return true;
}

// ... non-static const member ...
if (auto *MD10.1
'MD' is null
 = dyn_cast<CXXMethodDecl>(FD)) {
10
←
Assuming 'FD' is not a 'CXXMethodDecl'→
11
←
Taking false branch→
  assert(!MD->isStatic() && "comparison function cannot be a static member")((void)0);
  if (!MD->isConst()) {
    SourceLocation InsertLoc;
    if (FunctionTypeLoc Loc = MD->getFunctionTypeLoc())
      InsertLoc = getLocForEndOfToken(Loc.getRParenLoc());
    // Don't diagnose an implicit 'operator=='; we will have diagnosed the
    // corresponding defaulted 'operator<=>' already.
    if (!MD->isImplicit()) {
      Diag(MD->getLocation(), diag::err_defaulted_comparison_non_const)
        << (int)DCK << FixItHint::CreateInsertion(InsertLoc, " const");
    }

    // Add the 'const' to the type to recover.
    const auto *FPT = MD->getType()->castAs<FunctionProtoType>();
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    EPI.TypeQuals.addConst();
    MD->setType(Context.getFunctionType(FPT->getReturnType(),
                                        FPT->getParamTypes(), EPI));
  }
} else {
  // A non-member function declared in a class must be a friend.
  assert(FD->getFriendObjectKind() && "expected a friend declaration")((void)0);
}

// C++2a [class.eq]p1, [class.rel]p1:
//   A [defaulted comparison other than <=>] shall have a declared return
//   type bool.
if (DCK != DefaultedComparisonKind::ThreeWay &&
12
←
Assuming 'DCK' is equal to ThreeWay→
13
←
Taking false branch→
    !FD->getDeclaredReturnType()->isDependentType() &&
    !Context.hasSameType(FD->getDeclaredReturnType(), Context.BoolTy)) {
  Diag(FD->getLocation(), diag::err_defaulted_comparison_return_type_not_bool)
      << (int)DCK << FD->getDeclaredReturnType() << Context.BoolTy
      << FD->getReturnTypeSourceRange();
  return true;
}
// C++2a [class.spaceship]p2 [P2002R0]:
//   Let R be the declared return type [...]. If R is auto, [...]. Otherwise,
//   R shall not contain a placeholder type.
if (DCK13.1
'DCK' is equal to ThreeWay
 == DefaultedComparisonKind::ThreeWay &&
15
←
Taking false branch→
    FD->getDeclaredReturnType()->getContainedDeducedType() &&
14
←
Assuming the condition is false→
    !Context.hasSameType(FD->getDeclaredReturnType(),
                         Context.getAutoDeductType())) {
  Diag(FD->getLocation(),
       diag::err_defaulted_comparison_deduced_return_type_not_auto)
      << (int)DCK << FD->getDeclaredReturnType() << Context.AutoDeductTy
      << FD->getReturnTypeSourceRange();
  return true;
}

// For a defaulted function in a dependent class, defer all remaining checks
// until instantiation.
if (RD->isDependentType())
16
←
Called C++ object pointer is null
  return false;

// Determine whether the function should be defined as deleted.
DefaultedComparisonInfo Info =
    DefaultedComparisonAnalyzer(*this, RD, FD, DCK).visit();

bool First = FD == FD->getCanonicalDecl();

// If we want to delete the function, then do so; there's nothing else to
// check in that case.
if (Info.Deleted) {
  if (!First) {
    // C++11 [dcl.fct.def.default]p4:
    //   [For a] user-provided explicitly-defaulted function [...] if such a
    //   function is implicitly defined as deleted, the program is ill-formed.
    //
    // This is really just a consequence of the general rule that you can
    // only delete a function on its first declaration.
    Diag(FD->getLocation(), diag::err_non_first_default_compare_deletes)
        << FD->isImplicit() << (int)DCK;
    DefaultedComparisonAnalyzer(*this, RD, FD, DCK,
                                DefaultedComparisonAnalyzer::ExplainDeleted)
        .visit();
    return true;
  }

  SetDeclDeleted(FD, FD->getLocation());
  if (!inTemplateInstantiation() && !FD->isImplicit()) {
    Diag(FD->getLocation(), diag::warn_defaulted_comparison_deleted)
        << (int)DCK;
    DefaultedComparisonAnalyzer(*this, RD, FD, DCK,
                                DefaultedComparisonAnalyzer::ExplainDeleted)
        .visit();
  }
  return false;
}

// C++2a [class.spaceship]p2:
//   The return type is deduced as the common comparison type of R0, R1, ...
if (DCK == DefaultedComparisonKind::ThreeWay &&
    FD->getDeclaredReturnType()->isUndeducedAutoType()) {
  SourceLocation RetLoc = FD->getReturnTypeSourceRange().getBegin();
  if (RetLoc.isInvalid())
    RetLoc = FD->getBeginLoc();
  // FIXME: Should we really care whether we have the complete type and the
  // 'enumerator' constants here? A forward declaration seems sufficient.
  QualType Cat = CheckComparisonCategoryType(
      Info.Category, RetLoc, ComparisonCategoryUsage::DefaultedOperator);
  if (Cat.isNull())
    return true;
  Context.adjustDeducedFunctionResultType(
      FD, SubstAutoType(FD->getDeclaredReturnType(), Cat));
}

// C++2a [dcl.fct.def.default]p3 [P2002R0]:
//   An explicitly-defaulted function that is not defined as deleted may be
//   declared constexpr or consteval only if it is constexpr-compatible.
// C++2a [class.compare.default]p3 [P2002R0]:
//   A defaulted comparison function is constexpr-compatible if it satisfies
//   the requirements for a constexpr function [...]
// The only relevant requirements are that the parameter and return types are
// literal types. The remaining conditions are checked by the analyzer.
if (FD->isConstexpr()) {
  if (CheckConstexprReturnType(*this, FD, CheckConstexprKind::Diagnose) &&
      CheckConstexprParameterTypes(*this, FD, CheckConstexprKind::Diagnose) &&
      !Info.Constexpr) {
    Diag(FD->getBeginLoc(),
         diag::err_incorrect_defaulted_comparison_constexpr)
        << FD->isImplicit() << (int)DCK << FD->isConsteval();
    DefaultedComparisonAnalyzer(*this, RD, FD, DCK,
                                DefaultedComparisonAnalyzer::ExplainConstexpr)
        .visit();
  }
}

// C++2a [dcl.fct.def.default]p3 [P2002R0]:
//   If a constexpr-compatible function is explicitly defaulted on its first
//   declaration, it is implicitly considered to be constexpr.
// FIXME: Only applying this to the first declaration seems problematic, as
// simple reorderings can affect the meaning of the program.
if (First && !FD->isConstexpr() && Info.Constexpr)
  FD->setConstexprKind(ConstexprSpecKind::Constexpr);

// C++2a [except.spec]p3:
//   If a declaration of a function does not have a noexcept-specifier
//   [and] is defaulted on its first declaration, [...] the exception
//   specification is as specified below
if (FD->getExceptionSpecType() == EST_None) {
  auto *FPT = FD->getType()->castAs<FunctionProtoType>();
  FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
  EPI.ExceptionSpec.Type = EST_Unevaluated;
  EPI.ExceptionSpec.SourceDecl = FD;
  FD->setType(Context.getFunctionType(FPT->getReturnType(),
                                      FPT->getParamTypes(), EPI));
}

return false;
8579}

8581void Sema::DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
                                           FunctionDecl *Spaceship) {
Sema::CodeSynthesisContext Ctx;
Ctx.Kind = Sema::CodeSynthesisContext::DeclaringImplicitEqualityComparison;
Ctx.PointOfInstantiation = Spaceship->getEndLoc();
Ctx.Entity = Spaceship;
pushCodeSynthesisContext(Ctx);

if (FunctionDecl *EqualEqual = SubstSpaceshipAsEqualEqual(RD, Spaceship))
  EqualEqual->setImplicit();

popCodeSynthesisContext();
8593}

8595void Sema::DefineDefaultedComparison(SourceLocation UseLoc, FunctionDecl *FD,
                                   DefaultedComparisonKind DCK) {
assert(FD->isDefaulted() && !FD->isDeleted() &&((void)0)
       !FD->doesThisDeclarationHaveABody())((void)0);
if (FD->willHaveBody() || FD->isInvalidDecl())
  return;

SynthesizedFunctionScope Scope(*this, FD);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(UseLoc);

{
  // Build and set up the function body.
  CXXRecordDecl *RD = cast<CXXRecordDecl>(FD->getLexicalParent());
  SourceLocation BodyLoc =
      FD->getEndLoc().isValid() ? FD->getEndLoc() : FD->getLocation();
  StmtResult Body =
      DefaultedComparisonSynthesizer(*this, RD, FD, DCK, BodyLoc).build();
  if (Body.isInvalid()) {
    FD->setInvalidDecl();
    return;
  }
  FD->setBody(Body.get());
  FD->markUsed(Context);
}

// The exception specification is needed because we are defining the
// function. Note that this will reuse the body we just built.
ResolveExceptionSpec(UseLoc, FD->getType()->castAs<FunctionProtoType>());

if (ASTMutationListener *L = getASTMutationListener())
  L->CompletedImplicitDefinition(FD);
8628}

8630static Sema::ImplicitExceptionSpecification
8631ComputeDefaultedComparisonExceptionSpec(Sema &S, SourceLocation Loc,
                                      FunctionDecl *FD,
                                      Sema::DefaultedComparisonKind DCK) {
ComputingExceptionSpec CES(S, FD, Loc);
Sema::ImplicitExceptionSpecification ExceptSpec(S);

if (FD->isInvalidDecl())
  return ExceptSpec;

// The common case is that we just defined the comparison function. In that
// case, just look at whether the body can throw.
if (FD->hasBody()) {
  ExceptSpec.CalledStmt(FD->getBody());
} else {
  // Otherwise, build a body so we can check it. This should ideally only
  // happen when we're not actually marking the function referenced. (This is
  // only really important for efficiency: we don't want to build and throw
  // away bodies for comparison functions more than we strictly need to.)

  // Pretend to synthesize the function body in an unevaluated context.
  // Note that we can't actually just go ahead and define the function here:
  // we are not permitted to mark its callees as referenced.
  Sema::SynthesizedFunctionScope Scope(S, FD);
  EnterExpressionEvaluationContext Context(
      S, Sema::ExpressionEvaluationContext::Unevaluated);

  CXXRecordDecl *RD = cast<CXXRecordDecl>(FD->getLexicalParent());
  SourceLocation BodyLoc =
      FD->getEndLoc().isValid() ? FD->getEndLoc() : FD->getLocation();
  StmtResult Body =
      DefaultedComparisonSynthesizer(S, RD, FD, DCK, BodyLoc).build();
  if (!Body.isInvalid())
    ExceptSpec.CalledStmt(Body.get());

  // FIXME: Can we hold onto this body and just transform it to potentially
  // evaluated when we're asked to define the function rather than rebuilding
  // it? Either that, or we should only build the bits of the body that we
  // need (the expressions, not the statements).
}

return ExceptSpec;
8672}

8674void Sema::CheckDelayedMemberExceptionSpecs() {
decltype(DelayedOverridingExceptionSpecChecks) Overriding;
decltype(DelayedEquivalentExceptionSpecChecks) Equivalent;

std::swap(Overriding, DelayedOverridingExceptionSpecChecks);
std::swap(Equivalent, DelayedEquivalentExceptionSpecChecks);

// Perform any deferred checking of exception specifications for virtual
// destructors.
for (auto &Check : Overriding)
  CheckOverridingFunctionExceptionSpec(Check.first, Check.second);

// Perform any deferred checking of exception specifications for befriended
// special members.
for (auto &Check : Equivalent)
  CheckEquivalentExceptionSpec(Check.second, Check.first);
8690}

8692namespace {
8693/// CRTP base class for visiting operations performed by a special member
8694/// function (or inherited constructor).
8695template<typename Derived>
8696struct SpecialMemberVisitor {
Sema &S;
CXXMethodDecl *MD;
Sema::CXXSpecialMember CSM;
Sema::InheritedConstructorInfo *ICI;

// Properties of the special member, computed for convenience.
bool IsConstructor = false, IsAssignment = false, ConstArg = false;

SpecialMemberVisitor(Sema &S, CXXMethodDecl *MD, Sema::CXXSpecialMember CSM,
                     Sema::InheritedConstructorInfo *ICI)
    : S(S), MD(MD), CSM(CSM), ICI(ICI) {
  switch (CSM) {
  case Sema::CXXDefaultConstructor:
  case Sema::CXXCopyConstructor:
  case Sema::CXXMoveConstructor:
    IsConstructor = true;
    break;
  case Sema::CXXCopyAssignment:
  case Sema::CXXMoveAssignment:
    IsAssignment = true;
    break;
  case Sema::CXXDestructor:
    break;
  case Sema::CXXInvalid:
    llvm_unreachable("invalid special member kind")__builtin_unreachable();
  }

  if (MD->getNumParams()) {
    if (const ReferenceType *RT =
            MD->getParamDecl(0)->getType()->getAs<ReferenceType>())
      ConstArg = RT->getPointeeType().isConstQualified();
  }
}

Derived &getDerived() { return static_cast<Derived&>(*this); }

/// Is this a "move" special member?
bool isMove() const {
  return CSM == Sema::CXXMoveConstructor || CSM == Sema::CXXMoveAssignment;
}

/// Look up the corresponding special member in the given class.
Sema::SpecialMemberOverloadResult lookupIn(CXXRecordDecl *Class,
                                           unsigned Quals, bool IsMutable) {
  return lookupCallFromSpecialMember(S, Class, CSM, Quals,
                                     ConstArg && !IsMutable);
}

/// Look up the constructor for the specified base class to see if it's
/// overridden due to this being an inherited constructor.
Sema::SpecialMemberOverloadResult lookupInheritedCtor(CXXRecordDecl *Class) {
  if (!ICI)
    return {};
  assert(CSM == Sema::CXXDefaultConstructor)((void)0);
  auto *BaseCtor =
    cast<CXXConstructorDecl>(MD)->getInheritedConstructor().getConstructor();
  if (auto *MD = ICI->findConstructorForBase(Class, BaseCtor).first)
    return MD;
  return {};
}

/// A base or member subobject.
typedef llvm::PointerUnion<CXXBaseSpecifier*, FieldDecl*> Subobject;

/// Get the location to use for a subobject in diagnostics.
static SourceLocation getSubobjectLoc(Subobject Subobj) {
  // FIXME: For an indirect virtual base, the direct base leading to
  // the indirect virtual base would be a more useful choice.
  if (auto *B = Subobj.dyn_cast<CXXBaseSpecifier*>())
    return B->getBaseTypeLoc();
  else
    return Subobj.get<FieldDecl*>()->getLocation();
}

enum BasesToVisit {
  /// Visit all non-virtual (direct) bases.
  VisitNonVirtualBases,
  /// Visit all direct bases, virtual or not.
  VisitDirectBases,
  /// Visit all non-virtual bases, and all virtual bases if the class
  /// is not abstract.
  VisitPotentiallyConstructedBases,
  /// Visit all direct or virtual bases.
  VisitAllBases
};

// Visit the bases and members of the class.
bool visit(BasesToVisit Bases) {
  CXXRecordDecl *RD = MD->getParent();

  if (Bases == VisitPotentiallyConstructedBases)
    Bases = RD->isAbstract() ? VisitNonVirtualBases : VisitAllBases;

  for (auto &B : RD->bases())
    if ((Bases == VisitDirectBases || !B.isVirtual()) &&
        getDerived().visitBase(&B))
      return true;

  if (Bases == VisitAllBases)
    for (auto &B : RD->vbases())
      if (getDerived().visitBase(&B))
        return true;

  for (auto *F : RD->fields())
    if (!F->isInvalidDecl() && !F->isUnnamedBitfield() &&
        getDerived().visitField(F))
      return true;

  return false;
}
8807};
8808}

8810namespace {
8811struct SpecialMemberDeletionInfo
  : SpecialMemberVisitor<SpecialMemberDeletionInfo> {
bool Diagnose;

SourceLocation Loc;

bool AllFieldsAreConst;

SpecialMemberDeletionInfo(Sema &S, CXXMethodDecl *MD,
                          Sema::CXXSpecialMember CSM,
                          Sema::InheritedConstructorInfo *ICI, bool Diagnose)
    : SpecialMemberVisitor(S, MD, CSM, ICI), Diagnose(Diagnose),
      Loc(MD->getLocation()), AllFieldsAreConst(true) {}

bool inUnion() const { return MD->getParent()->isUnion(); }

Sema::CXXSpecialMember getEffectiveCSM() {
  return ICI ? Sema::CXXInvalid : CSM;
}

bool shouldDeleteForVariantObjCPtrMember(FieldDecl *FD, QualType FieldType);

bool visitBase(CXXBaseSpecifier *Base) { return shouldDeleteForBase(Base); }
bool visitField(FieldDecl *Field) { return shouldDeleteForField(Field); }

bool shouldDeleteForBase(CXXBaseSpecifier *Base);
bool shouldDeleteForField(FieldDecl *FD);
bool shouldDeleteForAllConstMembers();

bool shouldDeleteForClassSubobject(CXXRecordDecl *Class, Subobject Subobj,
                                   unsigned Quals);
bool shouldDeleteForSubobjectCall(Subobject Subobj,
                                  Sema::SpecialMemberOverloadResult SMOR,
                                  bool IsDtorCallInCtor);

bool isAccessible(Subobject Subobj, CXXMethodDecl *D);
8847};
8848}

8850/// Is the given special member inaccessible when used on the given
8851/// sub-object.
8852bool SpecialMemberDeletionInfo::isAccessible(Subobject Subobj,
                                           CXXMethodDecl *target) {
/// If we're operating on a base class, the object type is the
/// type of this special member.
QualType objectTy;
AccessSpecifier access = target->getAccess();
if (CXXBaseSpecifier *base = Subobj.dyn_cast<CXXBaseSpecifier*>()) {
  objectTy = S.Context.getTypeDeclType(MD->getParent());
  access = CXXRecordDecl::MergeAccess(base->getAccessSpecifier(), access);

// If we're operating on a field, the object type is the type of the field.
} else {
  objectTy = S.Context.getTypeDeclType(target->getParent());
}

return S.isMemberAccessibleForDeletion(
    target->getParent(), DeclAccessPair::make(target, access), objectTy);
8869}

8871/// Check whether we should delete a special member due to the implicit
8872/// definition containing a call to a special member of a subobject.
8873bool SpecialMemberDeletionInfo::shouldDeleteForSubobjectCall(
  Subobject Subobj, Sema::SpecialMemberOverloadResult SMOR,
  bool IsDtorCallInCtor) {
CXXMethodDecl *Decl = SMOR.getMethod();
FieldDecl *Field = Subobj.dyn_cast<FieldDecl*>();

int DiagKind = -1;

if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::NoMemberOrDeleted)
  DiagKind = !Decl ? 0 : 1;
else if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::Ambiguous)
  DiagKind = 2;
else if (!isAccessible(Subobj, Decl))
  DiagKind = 3;
else if (!IsDtorCallInCtor && Field && Field->getParent()->isUnion() &&
         !Decl->isTrivial()) {
  // A member of a union must have a trivial corresponding special member.
  // As a weird special case, a destructor call from a union's constructor
  // must be accessible and non-deleted, but need not be trivial. Such a
  // destructor is never actually called, but is semantically checked as
  // if it were.
  DiagKind = 4;
}

if (DiagKind == -1)
  return false;

if (Diagnose) {
  if (Field) {
    S.Diag(Field->getLocation(),
           diag::note_deleted_special_member_class_subobject)
      << getEffectiveCSM() << MD->getParent() << /*IsField*/true
      << Field << DiagKind << IsDtorCallInCtor << /*IsObjCPtr*/false;
  } else {
    CXXBaseSpecifier *Base = Subobj.get<CXXBaseSpecifier*>();
    S.Diag(Base->getBeginLoc(),
           diag::note_deleted_special_member_class_subobject)
        << getEffectiveCSM() << MD->getParent() << /*IsField*/ false
        << Base->getType() << DiagKind << IsDtorCallInCtor
        << /*IsObjCPtr*/false;
  }

  if (DiagKind == 1)
    S.NoteDeletedFunction(Decl);
  // FIXME: Explain inaccessibility if DiagKind == 3.
}

return true;
8921}

8923/// Check whether we should delete a special member function due to having a
8924/// direct or virtual base class or non-static data member of class type M.
8925bool SpecialMemberDeletionInfo::shouldDeleteForClassSubobject(
  CXXRecordDecl *Class, Subobject Subobj, unsigned Quals) {
FieldDecl *Field = Subobj.dyn_cast<FieldDecl*>();
bool IsMutable = Field && Field->isMutable();

// C++11 [class.ctor]p5:
// -- any direct or virtual base class, or non-static data member with no
//    brace-or-equal-initializer, has class type M (or array thereof) and
//    either M has no default constructor or overload resolution as applied
//    to M's default constructor results in an ambiguity or in a function
//    that is deleted or inaccessible
// C++11 [class.copy]p11, C++11 [class.copy]p23:
// -- a direct or virtual base class B that cannot be copied/moved because
//    overload resolution, as applied to B's corresponding special member,
//    results in an ambiguity or a function that is deleted or inaccessible
//    from the defaulted special member
// C++11 [class.dtor]p5:
// -- any direct or virtual base class [...] has a type with a destructor
//    that is deleted or inaccessible
if (!(CSM == Sema::CXXDefaultConstructor &&
      Field && Field->hasInClassInitializer()) &&
    shouldDeleteForSubobjectCall(Subobj, lookupIn(Class, Quals, IsMutable),
                                 false))
  return true;

// C++11 [class.ctor]p5, C++11 [class.copy]p11:
// -- any direct or virtual base class or non-static data member has a
//    type with a destructor that is deleted or inaccessible
if (IsConstructor) {
  Sema::SpecialMemberOverloadResult SMOR =
      S.LookupSpecialMember(Class, Sema::CXXDestructor,
                            false, false, false, false, false);
  if (shouldDeleteForSubobjectCall(Subobj, SMOR, true))
    return true;
}

return false;
8962}

8964bool SpecialMemberDeletionInfo::shouldDeleteForVariantObjCPtrMember(
  FieldDecl *FD, QualType FieldType) {
// The defaulted special functions are defined as deleted if this is a variant
// member with a non-trivial ownership type, e.g., ObjC __strong or __weak
// type under ARC.
if (!FieldType.hasNonTrivialObjCLifetime())
  return false;

// Don't make the defaulted default constructor defined as deleted if the
// member has an in-class initializer.
if (CSM == Sema::CXXDefaultConstructor && FD->hasInClassInitializer())
  return false;

if (Diagnose) {
  auto *ParentClass = cast<CXXRecordDecl>(FD->getParent());
  S.Diag(FD->getLocation(),
         diag::note_deleted_special_member_class_subobject)
      << getEffectiveCSM() << ParentClass << /*IsField*/true
      << FD << 4 << /*IsDtorCallInCtor*/false << /*IsObjCPtr*/true;
}

return true;
8986}

8988/// Check whether we should delete a special member function due to the class
8989/// having a particular direct or virtual base class.
8990bool SpecialMemberDeletionInfo::shouldDeleteForBase(CXXBaseSpecifier *Base) {
CXXRecordDecl *BaseClass = Base->getType()->getAsCXXRecordDecl();
// If program is correct, BaseClass cannot be null, but if it is, the error
// must be reported elsewhere.
if (!BaseClass)
  return false;
// If we have an inheriting constructor, check whether we're calling an
// inherited constructor instead of a default constructor.
Sema::SpecialMemberOverloadResult SMOR = lookupInheritedCtor(BaseClass);
if (auto *BaseCtor = SMOR.getMethod()) {
  // Note that we do not check access along this path; other than that,
  // this is the same as shouldDeleteForSubobjectCall(Base, BaseCtor, false);
  // FIXME: Check that the base has a usable destructor! Sink this into
  // shouldDeleteForClassSubobject.
  if (BaseCtor->isDeleted() && Diagnose) {
    S.Diag(Base->getBeginLoc(),
           diag::note_deleted_special_member_class_subobject)
        << getEffectiveCSM() << MD->getParent() << /*IsField*/ false
        << Base->getType() << /*Deleted*/ 1 << /*IsDtorCallInCtor*/ false
        << /*IsObjCPtr*/false;
    S.NoteDeletedFunction(BaseCtor);
  }
  return BaseCtor->isDeleted();
}
return shouldDeleteForClassSubobject(BaseClass, Base, 0);
9015}

9017/// Check whether we should delete a special member function due to the class
9018/// having a particular non-static data member.
9019bool SpecialMemberDeletionInfo::shouldDeleteForField(FieldDecl *FD) {
QualType FieldType = S.Context.getBaseElementType(FD->getType());
CXXRecordDecl *FieldRecord = FieldType->getAsCXXRecordDecl();

if (inUnion() && shouldDeleteForVariantObjCPtrMember(FD, FieldType))
  return true;

if (CSM == Sema::CXXDefaultConstructor) {
  // For a default constructor, all references must be initialized in-class
  // and, if a union, it must have a non-const member.
  if (FieldType->isReferenceType() && !FD->hasInClassInitializer()) {
    if (Diagnose)
      S.Diag(FD->getLocation(), diag::note_deleted_default_ctor_uninit_field)
        << !!ICI << MD->getParent() << FD << FieldType << /*Reference*/0;
    return true;
  }
  // C++11 [class.ctor]p5: any non-variant non-static data member of
  // const-qualified type (or array thereof) with no
  // brace-or-equal-initializer does not have a user-provided default
  // constructor.
  if (!inUnion() && FieldType.isConstQualified() &&
      !FD->hasInClassInitializer() &&
      (!FieldRecord || !FieldRecord->hasUserProvidedDefaultConstructor())) {
    if (Diagnose)
      S.Diag(FD->getLocation(), diag::note_deleted_default_ctor_uninit_field)
        << !!ICI << MD->getParent() << FD << FD->getType() << /*Const*/1;
    return true;
  }

  if (inUnion() && !FieldType.isConstQualified())
    AllFieldsAreConst = false;
} else if (CSM == Sema::CXXCopyConstructor) {
  // For a copy constructor, data members must not be of rvalue reference
  // type.
  if (FieldType->isRValueReferenceType()) {
    if (Diagnose)
      S.Diag(FD->getLocation(), diag::note_deleted_copy_ctor_rvalue_reference)
        << MD->getParent() << FD << FieldType;
    return true;
  }
} else if (IsAssignment) {
  // For an assignment operator, data members must not be of reference type.
  if (FieldType->isReferenceType()) {
    if (Diagnose)
      S.Diag(FD->getLocation(), diag::note_deleted_assign_field)
        << isMove() << MD->getParent() << FD << FieldType << /*Reference*/0;
    return true;
  }
  if (!FieldRecord && FieldType.isConstQualified()) {
    // C++11 [class.copy]p23:
    // -- a non-static data member of const non-class type (or array thereof)
    if (Diagnose)
      S.Diag(FD->getLocation(), diag::note_deleted_assign_field)
        << isMove() << MD->getParent() << FD << FD->getType() << /*Const*/1;
    return true;
  }
}

if (FieldRecord) {
  // Some additional restrictions exist on the variant members.
  if (!inUnion() && FieldRecord->isUnion() &&
      FieldRecord->isAnonymousStructOrUnion()) {
    bool AllVariantFieldsAreConst = true;

    // FIXME: Handle anonymous unions declared within anonymous unions.
    for (auto *UI : FieldRecord->fields()) {
      QualType UnionFieldType = S.Context.getBaseElementType(UI->getType());

      if (shouldDeleteForVariantObjCPtrMember(&*UI, UnionFieldType))
        return true;

      if (!UnionFieldType.isConstQualified())
        AllVariantFieldsAreConst = false;

      CXXRecordDecl *UnionFieldRecord = UnionFieldType->getAsCXXRecordDecl();
      if (UnionFieldRecord &&
          shouldDeleteForClassSubobject(UnionFieldRecord, UI,
                                        UnionFieldType.getCVRQualifiers()))
        return true;
    }

    // At least one member in each anonymous union must be non-const
    if (CSM == Sema::CXXDefaultConstructor && AllVariantFieldsAreConst &&
        !FieldRecord->field_empty()) {
      if (Diagnose)
        S.Diag(FieldRecord->getLocation(),
               diag::note_deleted_default_ctor_all_const)
          << !!ICI << MD->getParent() << /*anonymous union*/1;
      return true;
    }

    // Don't check the implicit member of the anonymous union type.
    // This is technically non-conformant, but sanity demands it.
    return false;
  }

  if (shouldDeleteForClassSubobject(FieldRecord, FD,
                                    FieldType.getCVRQualifiers()))
    return true;
}

return false;
9121}

9123/// C++11 [class.ctor] p5:
9124///   A defaulted default constructor for a class X is defined as deleted if
9125/// X is a union and all of its variant members are of const-qualified type.
9126bool SpecialMemberDeletionInfo::shouldDeleteForAllConstMembers() {
// This is a silly definition, because it gives an empty union a deleted
// default constructor. Don't do that.
if (CSM == Sema::CXXDefaultConstructor && inUnion() && AllFieldsAreConst) {
  bool AnyFields = false;
  for (auto *F : MD->getParent()->fields())
    if ((AnyFields = !F->isUnnamedBitfield()))
      break;
  if (!AnyFields)
    return false;
  if (Diagnose)
    S.Diag(MD->getParent()->getLocation(),
           diag::note_deleted_default_ctor_all_const)
      << !!ICI << MD->getParent() << /*not anonymous union*/0;
  return true;
}
return false;
9143}

9145/// Determine whether a defaulted special member function should be defined as
9146/// deleted, as specified in C++11 [class.ctor]p5, C++11 [class.copy]p11,
9147/// C++11 [class.copy]p23, and C++11 [class.dtor]p5.
9148bool Sema::ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMember CSM,
                                   InheritedConstructorInfo *ICI,
                                   bool Diagnose) {
if (MD->isInvalidDecl())
  return false;
CXXRecordDecl *RD = MD->getParent();
assert(!RD->isDependentType() && "do deletion after instantiation")((void)0);
if (!LangOpts.CPlusPlus11 || RD->isInvalidDecl())
  return false;

// C++11 [expr.lambda.prim]p19:
//   The closure type associated with a lambda-expression has a
//   deleted (8.4.3) default constructor and a deleted copy
//   assignment operator.
// C++2a adds back these operators if the lambda has no lambda-capture.
if (RD->isLambda() && !RD->lambdaIsDefaultConstructibleAndAssignable() &&
    (CSM == CXXDefaultConstructor || CSM == CXXCopyAssignment)) {
  if (Diagnose)
    Diag(RD->getLocation(), diag::note_lambda_decl);
  return true;
}

// For an anonymous struct or union, the copy and assignment special members
// will never be used, so skip the check. For an anonymous union declared at
// namespace scope, the constructor and destructor are used.
if (CSM != CXXDefaultConstructor && CSM != CXXDestructor &&
    RD->isAnonymousStructOrUnion())
  return false;

// C++11 [class.copy]p7, p18:
//   If the class definition declares a move constructor or move assignment
//   operator, an implicitly declared copy constructor or copy assignment
//   operator is defined as deleted.
if (MD->isImplicit() &&
    (CSM == CXXCopyConstructor || CSM == CXXCopyAssignment)) {
  CXXMethodDecl *UserDeclaredMove = nullptr;

  // In Microsoft mode up to MSVC 2013, a user-declared move only causes the
  // deletion of the corresponding copy operation, not both copy operations.
  // MSVC 2015 has adopted the standards conforming behavior.
  bool DeletesOnlyMatchingCopy =
      getLangOpts().MSVCCompat &&
      !getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015);

  if (RD->hasUserDeclaredMoveConstructor() &&
      (!DeletesOnlyMatchingCopy || CSM == CXXCopyConstructor)) {
    if (!Diagnose) return true;

    // Find any user-declared move constructor.
    for (auto *I : RD->ctors()) {
      if (I->isMoveConstructor()) {
        UserDeclaredMove = I;
        break;
      }
    }
    assert(UserDeclaredMove)((void)0);
  } else if (RD->hasUserDeclaredMoveAssignment() &&
             (!DeletesOnlyMatchingCopy || CSM == CXXCopyAssignment)) {
    if (!Diagnose) return true;

    // Find any user-declared move assignment operator.
    for (auto *I : RD->methods()) {
      if (I->isMoveAssignmentOperator()) {
        UserDeclaredMove = I;
        break;
      }
    }
    assert(UserDeclaredMove)((void)0);
  }

  if (UserDeclaredMove) {
    Diag(UserDeclaredMove->getLocation(),
         diag::note_deleted_copy_user_declared_move)
      << (CSM == CXXCopyAssignment) << RD
      << UserDeclaredMove->isMoveAssignmentOperator();
    return true;
  }
}

// Do access control from the special member function
ContextRAII MethodContext(*this, MD);

// C++11 [class.dtor]p5:
// -- for a virtual destructor, lookup of the non-array deallocation function
//    results in an ambiguity or in a function that is deleted or inaccessible
if (CSM == CXXDestructor && MD->isVirtual()) {
  FunctionDecl *OperatorDelete = nullptr;
  DeclarationName Name =
    Context.DeclarationNames.getCXXOperatorName(OO_Delete);
  if (FindDeallocationFunction(MD->getLocation(), MD->getParent(), Name,
                               OperatorDelete, /*Diagnose*/false)) {
    if (Diagnose)
      Diag(RD->getLocation(), diag::note_deleted_dtor_no_operator_delete);
    return true;
  }
}

SpecialMemberDeletionInfo SMI(*this, MD, CSM, ICI, Diagnose);

// Per DR1611, do not consider virtual bases of constructors of abstract
// classes, since we are not going to construct them.
// Per DR1658, do not consider virtual bases of destructors of abstract
// classes either.
// Per DR2180, for assignment operators we only assign (and thus only
// consider) direct bases.
if (SMI.visit(SMI.IsAssignment ? SMI.VisitDirectBases
                               : SMI.VisitPotentiallyConstructedBases))
  return true;

if (SMI.shouldDeleteForAllConstMembers())
  return true;

if (getLangOpts().CUDA) {
  // We should delete the special member in CUDA mode if target inference
  // failed.
  // For inherited constructors (non-null ICI), CSM may be passed so that MD
  // is treated as certain special member, which may not reflect what special
  // member MD really is. However inferCUDATargetForImplicitSpecialMember
  // expects CSM to match MD, therefore recalculate CSM.
  assert(ICI || CSM == getSpecialMember(MD))((void)0);
  auto RealCSM = CSM;
  if (ICI)
    RealCSM = getSpecialMember(MD);

  return inferCUDATargetForImplicitSpecialMember(RD, RealCSM, MD,
                                                 SMI.ConstArg, Diagnose);
}

return false;
9277}

9279void Sema::DiagnoseDeletedDefaultedFunction(FunctionDecl *FD) {
DefaultedFunctionKind DFK = getDefaultedFunctionKind(FD);
assert(DFK && "not a defaultable function")((void)0);
assert(FD->isDefaulted() && FD->isDeleted() && "not defaulted and deleted")((void)0);

if (DFK.isSpecialMember()) {
  ShouldDeleteSpecialMember(cast<CXXMethodDecl>(FD), DFK.asSpecialMember(),
                            nullptr, /*Diagnose=*/true);
} else {
  DefaultedComparisonAnalyzer(
      *this, cast<CXXRecordDecl>(FD->getLexicalDeclContext()), FD,
      DFK.asComparison(), DefaultedComparisonAnalyzer::ExplainDeleted)
      .visit();
}
9293}

9295/// Perform lookup for a special member of the specified kind, and determine
9296/// whether it is trivial. If the triviality can be determined without the
9297/// lookup, skip it. This is intended for use when determining whether a
9298/// special member of a containing object is trivial, and thus does not ever
9299/// perform overload resolution for default constructors.
9300///
9301/// If \p Selected is not \c NULL, \c *Selected will be filled in with the
9302/// member that was most likely to be intended to be trivial, if any.
9303///
9304/// If \p ForCall is true, look at CXXRecord::HasTrivialSpecialMembersForCall to
9305/// determine whether the special member is trivial.
9306static bool findTrivialSpecialMember(Sema &S, CXXRecordDecl *RD,
                                   Sema::CXXSpecialMember CSM, unsigned Quals,
                                   bool ConstRHS,
                                   Sema::TrivialABIHandling TAH,
                                   CXXMethodDecl **Selected) {
if (Selected)
  *Selected = nullptr;

switch (CSM) {
case Sema::CXXInvalid:
  llvm_unreachable("not a special member")__builtin_unreachable();

case Sema::CXXDefaultConstructor:
  // C++11 [class.ctor]p5:
  //   A default constructor is trivial if:
  //    - all the [direct subobjects] have trivial default constructors
  //
  // Note, no overload resolution is performed in this case.
  if (RD->hasTrivialDefaultConstructor())
    return true;

  if (Selected) {
    // If there's a default constructor which could have been trivial, dig it
    // out. Otherwise, if there's any user-provided default constructor, point
    // to that as an example of why there's not a trivial one.
    CXXConstructorDecl *DefCtor = nullptr;
    if (RD->needsImplicitDefaultConstructor())
      S.DeclareImplicitDefaultConstructor(RD);
    for (auto *CI : RD->ctors()) {
      if (!CI->isDefaultConstructor())
        continue;
      DefCtor = CI;
      if (!DefCtor->isUserProvided())
        break;
    }

    *Selected = DefCtor;
  }

  return false;

case Sema::CXXDestructor:
  // C++11 [class.dtor]p5:
  //   A destructor is trivial if:
  //    - all the direct [subobjects] have trivial destructors
  if (RD->hasTrivialDestructor() ||
      (TAH == Sema::TAH_ConsiderTrivialABI &&
       RD->hasTrivialDestructorForCall()))
    return true;

  if (Selected) {
    if (RD->needsImplicitDestructor())
      S.DeclareImplicitDestructor(RD);
    *Selected = RD->getDestructor();
  }

  return false;

case Sema::CXXCopyConstructor:
  // C++11 [class.copy]p12:
  //   A copy constructor is trivial if:
  //    - the constructor selected to copy each direct [subobject] is trivial
  if (RD->hasTrivialCopyConstructor() ||
      (TAH == Sema::TAH_ConsiderTrivialABI &&
       RD->hasTrivialCopyConstructorForCall())) {
    if (Quals == Qualifiers::Const)
      // We must either select the trivial copy constructor or reach an
      // ambiguity; no need to actually perform overload resolution.
      return true;
  } else if (!Selected) {
    return false;
  }
  // In C++98, we are not supposed to perform overload resolution here, but we
  // treat that as a language defect, as suggested on cxx-abi-dev, to treat
  // cases like B as having a non-trivial copy constructor:
  //   struct A { template<typename T> A(T&); };
  //   struct B { mutable A a; };
  goto NeedOverloadResolution;

case Sema::CXXCopyAssignment:
  // C++11 [class.copy]p25:
  //   A copy assignment operator is trivial if:
  //    - the assignment operator selected to copy each direct [subobject] is
  //      trivial
  if (RD->hasTrivialCopyAssignment()) {
    if (Quals == Qualifiers::Const)
      return true;
  } else if (!Selected) {
    return false;
  }
  // In C++98, we are not supposed to perform overload resolution here, but we
  // treat that as a language defect.
  goto NeedOverloadResolution;

case Sema::CXXMoveConstructor:
case Sema::CXXMoveAssignment:
NeedOverloadResolution:
  Sema::SpecialMemberOverloadResult SMOR =
      lookupCallFromSpecialMember(S, RD, CSM, Quals, ConstRHS);

  // The standard doesn't describe how to behave if the lookup is ambiguous.
  // We treat it as not making the member non-trivial, just like the standard
  // mandates for the default constructor. This should rarely matter, because
  // the member will also be deleted.
  if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::Ambiguous)
    return true;

  if (!SMOR.getMethod()) {
    assert(SMOR.getKind() ==((void)0)
           Sema::SpecialMemberOverloadResult::NoMemberOrDeleted)((void)0);
    return false;
  }

  // We deliberately don't check if we found a deleted special member. We're
  // not supposed to!
  if (Selected)
    *Selected = SMOR.getMethod();

  if (TAH == Sema::TAH_ConsiderTrivialABI &&
      (CSM == Sema::CXXCopyConstructor || CSM == Sema::CXXMoveConstructor))
    return SMOR.getMethod()->isTrivialForCall();
  return SMOR.getMethod()->isTrivial();
}

llvm_unreachable("unknown special method kind")__builtin_unreachable();
9431}

9433static CXXConstructorDecl *findUserDeclaredCtor(CXXRecordDecl *RD) {
for (auto *CI : RD->ctors())
  if (!CI->isImplicit())
    return CI;

// Look for constructor templates.
typedef CXXRecordDecl::specific_decl_iterator<FunctionTemplateDecl> tmpl_iter;
for (tmpl_iter TI(RD->decls_begin()), TE(RD->decls_end()); TI != TE; ++TI) {
  if (CXXConstructorDecl *CD =
        dyn_cast<CXXConstructorDecl>(TI->getTemplatedDecl()))
    return CD;
}

return nullptr;
9447}

9449/// The kind of subobject we are checking for triviality. The values of this
9450/// enumeration are used in diagnostics.
9451enum TrivialSubobjectKind {
/// The subobject is a base class.
TSK_BaseClass,
/// The subobject is a non-static data member.
TSK_Field,
/// The object is actually the complete object.
TSK_CompleteObject
9458};

9460/// Check whether the special member selected for a given type would be trivial.
9461static bool checkTrivialSubobjectCall(Sema &S, SourceLocation SubobjLoc,
                                    QualType SubType, bool ConstRHS,
                                    Sema::CXXSpecialMember CSM,
                                    TrivialSubobjectKind Kind,
                                    Sema::TrivialABIHandling TAH, bool Diagnose) {
CXXRecordDecl *SubRD = SubType->getAsCXXRecordDecl();
if (!SubRD)
  return true;

CXXMethodDecl *Selected;
if (findTrivialSpecialMember(S, SubRD, CSM, SubType.getCVRQualifiers(),
                             ConstRHS, TAH, Diagnose ? &Selected : nullptr))
  return true;

if (Diagnose) {
  if (ConstRHS)
    SubType.addConst();

  if (!Selected && CSM == Sema::CXXDefaultConstructor) {
    S.Diag(SubobjLoc, diag::note_nontrivial_no_def_ctor)
      << Kind << SubType.getUnqualifiedType();
    if (CXXConstructorDecl *CD = findUserDeclaredCtor(SubRD))
      S.Diag(CD->getLocation(), diag::note_user_declared_ctor);
  } else if (!Selected)
    S.Diag(SubobjLoc, diag::note_nontrivial_no_copy)
      << Kind << SubType.getUnqualifiedType() << CSM << SubType;
  else if (Selected->isUserProvided()) {
    if (Kind == TSK_CompleteObject)
      S.Diag(Selected->getLocation(), diag::note_nontrivial_user_provided)
        << Kind << SubType.getUnqualifiedType() << CSM;
    else {
      S.Diag(SubobjLoc, diag::note_nontrivial_user_provided)
        << Kind << SubType.getUnqualifiedType() << CSM;
      S.Diag(Selected->getLocation(), diag::note_declared_at);
    }
  } else {
    if (Kind != TSK_CompleteObject)
      S.Diag(SubobjLoc, diag::note_nontrivial_subobject)
        << Kind << SubType.getUnqualifiedType() << CSM;

    // Explain why the defaulted or deleted special member isn't trivial.
    S.SpecialMemberIsTrivial(Selected, CSM, Sema::TAH_IgnoreTrivialABI,
                             Diagnose);
  }
}

return false;
9508}

9510/// Check whether the members of a class type allow a special member to be
9511/// trivial.
9512static bool checkTrivialClassMembers(Sema &S, CXXRecordDecl *RD,
                                   Sema::CXXSpecialMember CSM,
                                   bool ConstArg,
                                   Sema::TrivialABIHandling TAH,
                                   bool Diagnose) {
for (const auto *FI : RD->fields()) {
  if (FI->isInvalidDecl() || FI->isUnnamedBitfield())
    continue;

  QualType FieldType = S.Context.getBaseElementType(FI->getType());

  // Pretend anonymous struct or union members are members of this class.
  if (FI->isAnonymousStructOrUnion()) {
    if (!checkTrivialClassMembers(S, FieldType->getAsCXXRecordDecl(),
                                  CSM, ConstArg, TAH, Diagnose))
      return false;
    continue;
  }

  // C++11 [class.ctor]p5:
  //   A default constructor is trivial if [...]
  //    -- no non-static data member of its class has a
  //       brace-or-equal-initializer
  if (CSM == Sema::CXXDefaultConstructor && FI->hasInClassInitializer()) {
    if (Diagnose)
      S.Diag(FI->getLocation(), diag::note_nontrivial_default_member_init)
          << FI;
    return false;
  }

  // Objective C ARC 4.3.5:
  //   [...] nontrivally ownership-qualified types are [...] not trivially
  //   default constructible, copy constructible, move constructible, copy
  //   assignable, move assignable, or destructible [...]
  if (FieldType.hasNonTrivialObjCLifetime()) {
    if (Diagnose)
      S.Diag(FI->getLocation(), diag::note_nontrivial_objc_ownership)
        << RD << FieldType.getObjCLifetime();
    return false;
  }

  bool ConstRHS = ConstArg && !FI->isMutable();
  if (!checkTrivialSubobjectCall(S, FI->getLocation(), FieldType, ConstRHS,
                                 CSM, TSK_Field, TAH, Diagnose))
    return false;
}

return true;
9560}

9562/// Diagnose why the specified class does not have a trivial special member of
9563/// the given kind.
9564void Sema::DiagnoseNontrivial(const CXXRecordDecl *RD, CXXSpecialMember CSM) {
QualType Ty = Context.getRecordType(RD);

bool ConstArg = (CSM == CXXCopyConstructor || CSM == CXXCopyAssignment);
checkTrivialSubobjectCall(*this, RD->getLocation(), Ty, ConstArg, CSM,
                          TSK_CompleteObject, TAH_IgnoreTrivialABI,
                          /*Diagnose*/true);
9571}

9573/// Determine whether a defaulted or deleted special member function is trivial,
9574/// as specified in C++11 [class.ctor]p5, C++11 [class.copy]p12,
9575/// C++11 [class.copy]p25, and C++11 [class.dtor]p5.
9576bool Sema::SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
                                TrivialABIHandling TAH, bool Diagnose) {
assert(!MD->isUserProvided() && CSM != CXXInvalid && "not special enough")((void)0);

CXXRecordDecl *RD = MD->getParent();

bool ConstArg = false;

// C++11 [class.copy]p12, p25: [DR1593]
//   A [special member] is trivial if [...] its parameter-type-list is
//   equivalent to the parameter-type-list of an implicit declaration [...]
switch (CSM) {
case CXXDefaultConstructor:
case CXXDestructor:
  // Trivial default constructors and destructors cannot have parameters.
  break;

case CXXCopyConstructor:
case CXXCopyAssignment: {
  // Trivial copy operations always have const, non-volatile parameter types.
  ConstArg = true;
  const ParmVarDecl *Param0 = MD->getParamDecl(0);
  const ReferenceType *RT = Param0->getType()->getAs<ReferenceType>();
  if (!RT || RT->getPointeeType().getCVRQualifiers() != Qualifiers::Const) {
    if (Diagnose)
      Diag(Param0->getLocation(), diag::note_nontrivial_param_type)
        << Param0->getSourceRange() << Param0->getType()
        << Context.getLValueReferenceType(
             Context.getRecordType(RD).withConst());
    return false;
  }
  break;
}

case CXXMoveConstructor:
case CXXMoveAssignment: {
  // Trivial move operations always have non-cv-qualified parameters.
  const ParmVarDecl *Param0 = MD->getParamDecl(0);
  const RValueReferenceType *RT =
    Param0->getType()->getAs<RValueReferenceType>();
  if (!RT || RT->getPointeeType().getCVRQualifiers()) {
    if (Diagnose)
      Diag(Param0->getLocation(), diag::note_nontrivial_param_type)
        << Param0->getSourceRange() << Param0->getType()
        << Context.getRValueReferenceType(Context.getRecordType(RD));
    return false;
  }
  break;
}

case CXXInvalid:
  llvm_unreachable("not a special member")__builtin_unreachable();
}

if (MD->getMinRequiredArguments() < MD->getNumParams()) {
  if (Diagnose)
    Diag(MD->getParamDecl(MD->getMinRequiredArguments())->getLocation(),
         diag::note_nontrivial_default_arg)
      << MD->getParamDecl(MD->getMinRequiredArguments())->getSourceRange();
  return false;
}
if (MD->isVariadic()) {
  if (Diagnose)
    Diag(MD->getLocation(), diag::note_nontrivial_variadic);
  return false;
}

// C++11 [class.ctor]p5, C++11 [class.dtor]p5:
//   A copy/move [constructor or assignment operator] is trivial if
//    -- the [member] selected to copy/move each direct base class subobject
//       is trivial
//
// C++11 [class.copy]p12, C++11 [class.copy]p25:
//   A [default constructor or destructor] is trivial if
//    -- all the direct base classes have trivial [default constructors or
//       destructors]
for (const auto &BI : RD->bases())
  if (!checkTrivialSubobjectCall(*this, BI.getBeginLoc(), BI.getType(),
                                 ConstArg, CSM, TSK_BaseClass, TAH, Diagnose))
    return false;

// C++11 [class.ctor]p5, C++11 [class.dtor]p5:
//   A copy/move [constructor or assignment operator] for a class X is
//   trivial if
//    -- for each non-static data member of X that is of class type (or array
//       thereof), the constructor selected to copy/move that member is
//       trivial
//
// C++11 [class.copy]p12, C++11 [class.copy]p25:
//   A [default constructor or destructor] is trivial if
//    -- for all of the non-static data members of its class that are of class
//       type (or array thereof), each such class has a trivial [default
//       constructor or destructor]
if (!checkTrivialClassMembers(*this, RD, CSM, ConstArg, TAH, Diagnose))
  return false;

// C++11 [class.dtor]p5:
//   A destructor is trivial if [...]
//    -- the destructor is not virtual
if (CSM == CXXDestructor && MD->isVirtual()) {
  if (Diagnose)
    Diag(MD->getLocation(), diag::note_nontrivial_virtual_dtor) << RD;
  return false;
}

// C++11 [class.ctor]p5, C++11 [class.copy]p12, C++11 [class.copy]p25:
//   A [special member] for class X is trivial if [...]
//    -- class X has no virtual functions and no virtual base classes
if (CSM != CXXDestructor && MD->getParent()->isDynamicClass()) {
  if (!Diagnose)
    return false;

  if (RD->getNumVBases()) {
    // Check for virtual bases. We already know that the corresponding
    // member in all bases is trivial, so vbases must all be direct.
    CXXBaseSpecifier &BS = *RD->vbases_begin();
    assert(BS.isVirtual())((void)0);
    Diag(BS.getBeginLoc(), diag::note_nontrivial_has_virtual) << RD << 1;
    return false;
  }

  // Must have a virtual method.
  for (const auto *MI : RD->methods()) {
    if (MI->isVirtual()) {
      SourceLocation MLoc = MI->getBeginLoc();
      Diag(MLoc, diag::note_nontrivial_has_virtual) << RD << 0;
      return false;
    }
  }

  llvm_unreachable("dynamic class with no vbases and no virtual functions")__builtin_unreachable();
}

// Looks like it's trivial!
return true;
9711}

9713namespace {
9714struct FindHiddenVirtualMethod {
Sema *S;
CXXMethodDecl *Method;
llvm::SmallPtrSet<const CXXMethodDecl *, 8> OverridenAndUsingBaseMethods;
SmallVector<CXXMethodDecl *, 8> OverloadedMethods;

9720private:
/// Check whether any most overridden method from MD in Methods
static bool CheckMostOverridenMethods(
    const CXXMethodDecl *MD,
    const llvm::SmallPtrSetImpl<const CXXMethodDecl *> &Methods) {
  if (MD->size_overridden_methods() == 0)
    return Methods.count(MD->getCanonicalDecl());
  for (const CXXMethodDecl *O : MD->overridden_methods())
    if (CheckMostOverridenMethods(O, Methods))
      return true;
  return false;
}

9733public:
/// Member lookup function that determines whether a given C++
/// method overloads virtual methods in a base class without overriding any,
/// to be used with CXXRecordDecl::lookupInBases().
bool operator()(const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
  RecordDecl *BaseRecord =
      Specifier->getType()->castAs<RecordType>()->getDecl();

  DeclarationName Name = Method->getDeclName();
  assert(Name.getNameKind() == DeclarationName::Identifier)((void)0);

  bool foundSameNameMethod = false;
  SmallVector<CXXMethodDecl *, 8> overloadedMethods;
  for (Path.Decls = BaseRecord->lookup(Name).begin();
       Path.Decls != DeclContext::lookup_iterator(); ++Path.Decls) {
    NamedDecl *D = *Path.Decls;
    if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
      MD = MD->getCanonicalDecl();
      foundSameNameMethod = true;
      // Interested only in hidden virtual methods.
      if (!MD->isVirtual())
        continue;
      // If the method we are checking overrides a method from its base
      // don't warn about the other overloaded methods. Clang deviates from
      // GCC by only diagnosing overloads of inherited virtual functions that
      // do not override any other virtual functions in the base. GCC's
      // -Woverloaded-virtual diagnoses any derived function hiding a virtual
      // function from a base class. These cases may be better served by a
      // warning (not specific to virtual functions) on call sites when the
      // call would select a different function from the base class, were it
      // visible.
      // See FIXME in test/SemaCXX/warn-overload-virtual.cpp for an example.
      if (!S->IsOverload(Method, MD, false))
        return true;
      // Collect the overload only if its hidden.
      if (!CheckMostOverridenMethods(MD, OverridenAndUsingBaseMethods))
        overloadedMethods.push_back(MD);
    }
  }

  if (foundSameNameMethod)
    OverloadedMethods.append(overloadedMethods.begin(),
                             overloadedMethods.end());
  return foundSameNameMethod;
}
9778};
9779} // end anonymous namespace

9781/// Add the most overriden methods from MD to Methods
9782static void AddMostOverridenMethods(const CXXMethodDecl *MD,
                      llvm::SmallPtrSetImpl<const CXXMethodDecl *>& Methods) {
if (MD->size_overridden_methods() == 0)
  Methods.insert(MD->getCanonicalDecl());
else
  for (const CXXMethodDecl *O : MD->overridden_methods())
    AddMostOverridenMethods(O, Methods);
9789}

9791/// Check if a method overloads virtual methods in a base class without
9792/// overriding any.
9793void Sema::FindHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods) {
if (!MD->getDeclName().isIdentifier())
  return;

CXXBasePaths Paths(/*FindAmbiguities=*/true, // true to look in all bases.
                   /*bool RecordPaths=*/false,
                   /*bool DetectVirtual=*/false);
FindHiddenVirtualMethod FHVM;
FHVM.Method = MD;
FHVM.S = this;

// Keep the base methods that were overridden or introduced in the subclass
// by 'using' in a set. A base method not in this set is hidden.
CXXRecordDecl *DC = MD->getParent();
DeclContext::lookup_result R = DC->lookup(MD->getDeclName());
for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E; ++I) {
  NamedDecl *ND = *I;
  if (UsingShadowDecl *shad = dyn_cast<UsingShadowDecl>(*I))
    ND = shad->getTargetDecl();
  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
    AddMostOverridenMethods(MD, FHVM.OverridenAndUsingBaseMethods);
}

if (DC->lookupInBases(FHVM, Paths))
  OverloadedMethods = FHVM.OverloadedMethods;
9819}

9821void Sema::NoteHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods) {
for (unsigned i = 0, e = OverloadedMethods.size(); i != e; ++i) {
  CXXMethodDecl *overloadedMD = OverloadedMethods[i];
  PartialDiagnostic PD = PDiag(
       diag::note_hidden_overloaded_virtual_declared_here) << overloadedMD;
  HandleFunctionTypeMismatch(PD, MD->getType(), overloadedMD->getType());
  Diag(overloadedMD->getLocation(), PD);
}
9830}

9832/// Diagnose methods which overload virtual methods in a base class
9833/// without overriding any.
9834void Sema::DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD) {
if (MD->isInvalidDecl())
  return;

if (Diags.isIgnored(diag::warn_overloaded_virtual, MD->getLocation()))
  return;

SmallVector<CXXMethodDecl *, 8> OverloadedMethods;
FindHiddenVirtualMethods(MD, OverloadedMethods);
if (!OverloadedMethods.empty()) {
  Diag(MD->getLocation(), diag::warn_overloaded_virtual)
    << MD << (OverloadedMethods.size() > 1);

  NoteHiddenVirtualMethods(MD, OverloadedMethods);
}
9849}

9851void Sema::checkIllFormedTrivialABIStruct(CXXRecordDecl &RD) {
auto PrintDiagAndRemoveAttr = [&](unsigned N) {
  // No diagnostics if this is a template instantiation.
  if (!isTemplateInstantiation(RD.getTemplateSpecializationKind())) {
    Diag(RD.getAttr<TrivialABIAttr>()->getLocation(),
         diag::ext_cannot_use_trivial_abi) << &RD;
    Diag(RD.getAttr<TrivialABIAttr>()->getLocation(),
         diag::note_cannot_use_trivial_abi_reason) << &RD << N;
  }
  RD.dropAttr<TrivialABIAttr>();
};

// Ill-formed if the copy and move constructors are deleted.
auto HasNonDeletedCopyOrMoveConstructor = [&]() {
  // If the type is dependent, then assume it might have
  // implicit copy or move ctor because we won't know yet at this point.
  if (RD.isDependentType())
    return true;
  if (RD.needsImplicitCopyConstructor() &&
      !RD.defaultedCopyConstructorIsDeleted())
    return true;
  if (RD.needsImplicitMoveConstructor() &&
      !RD.defaultedMoveConstructorIsDeleted())
    return true;
  for (const CXXConstructorDecl *CD : RD.ctors())
    if (CD->isCopyOrMoveConstructor() && !CD->isDeleted())
      return true;
  return false;
};

if (!HasNonDeletedCopyOrMoveConstructor()) {
  PrintDiagAndRemoveAttr(0);
  return;
}

// Ill-formed if the struct has virtual functions.
if (RD.isPolymorphic()) {
  PrintDiagAndRemoveAttr(1);
  return;
}

for (const auto &B : RD.bases()) {
  // Ill-formed if the base class is non-trivial for the purpose of calls or a
  // virtual base.
  if (!B.getType()->isDependentType() &&
      !B.getType()->getAsCXXRecordDecl()->canPassInRegisters()) {
    PrintDiagAndRemoveAttr(2);
    return;
  }

  if (B.isVirtual()) {
    PrintDiagAndRemoveAttr(3);
    return;
  }
}

for (const auto *FD : RD.fields()) {
  // Ill-formed if the field is an ObjectiveC pointer or of a type that is
  // non-trivial for the purpose of calls.
  QualType FT = FD->getType();
  if (FT.getObjCLifetime() == Qualifiers::OCL_Weak) {
    PrintDiagAndRemoveAttr(4);
    return;
  }

  if (const auto *RT = FT->getBaseElementTypeUnsafe()->getAs<RecordType>())
    if (!RT->isDependentType() &&
        !cast<CXXRecordDecl>(RT->getDecl())->canPassInRegisters()) {
      PrintDiagAndRemoveAttr(5);
      return;
    }
}
9923}

9925void Sema::ActOnFinishCXXMemberSpecification(
  Scope *S, SourceLocation RLoc, Decl *TagDecl, SourceLocation LBrac,
  SourceLocation RBrac, const ParsedAttributesView &AttrList) {
if (!TagDecl)
  return;

AdjustDeclIfTemplate(TagDecl);

for (const ParsedAttr &AL : AttrList) {
  if (AL.getKind() != ParsedAttr::AT_Visibility)
    continue;
  AL.setInvalid();
  Diag(AL.getLoc(), diag::warn_attribute_after_definition_ignored) << AL;
}

ActOnFields(S, RLoc, TagDecl, llvm::makeArrayRef(
            // strict aliasing violation!
            reinterpret_cast<Decl**>(FieldCollector->getCurFields()),
            FieldCollector->getCurNumFields()), LBrac, RBrac, AttrList);

CheckCompletedCXXClass(S, cast<CXXRecordDecl>(TagDecl));
9946}

9948/// Find the equality comparison functions that should be implicitly declared
9949/// in a given class definition, per C++2a [class.compare.default]p3.
9950static void findImplicitlyDeclaredEqualityComparisons(
  ASTContext &Ctx, CXXRecordDecl *RD,
  llvm::SmallVectorImpl<FunctionDecl *> &Spaceships) {
DeclarationName EqEq = Ctx.DeclarationNames.getCXXOperatorName(OO_EqualEqual);
if (!RD->lookup(EqEq).empty())
  // Member operator== explicitly declared: no implicit operator==s.
  return;

// Traverse friends looking for an '==' or a '<=>'.
for (FriendDecl *Friend : RD->friends()) {
  FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Friend->getFriendDecl());
  if (!FD) continue;

  if (FD->getOverloadedOperator() == OO_EqualEqual) {
    // Friend operator== explicitly declared: no implicit operator==s.
    Spaceships.clear();
    return;
  }

  if (FD->getOverloadedOperator() == OO_Spaceship &&
      FD->isExplicitlyDefaulted())
    Spaceships.push_back(FD);
}

// Look for members named 'operator<=>'.
DeclarationName Cmp = Ctx.DeclarationNames.getCXXOperatorName(OO_Spaceship);
for (NamedDecl *ND : RD->lookup(Cmp)) {
  // Note that we could find a non-function here (either a function template
  // or a using-declaration). Neither case results in an implicit
  // 'operator=='.
  if (auto *FD = dyn_cast<FunctionDecl>(ND))
    if (FD->isExplicitlyDefaulted())
      Spaceships.push_back(FD);
}
9984}

9986/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
9987/// special functions, such as the default constructor, copy
9988/// constructor, or destructor, to the given C++ class (C++
9989/// [special]p1).  This routine can only be executed just before the
9990/// definition of the class is complete.
9991void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
// Don't add implicit special members to templated classes.
// FIXME: This means unqualified lookups for 'operator=' within a class
// template don't work properly.
if (!ClassDecl->isDependentType()) {
  if (ClassDecl->needsImplicitDefaultConstructor()) {
    ++getASTContext().NumImplicitDefaultConstructors;

    if (ClassDecl->hasInheritedConstructor())
      DeclareImplicitDefaultConstructor(ClassDecl);
  }

  if (ClassDecl->needsImplicitCopyConstructor()) {
    ++getASTContext().NumImplicitCopyConstructors;

    // If the properties or semantics of the copy constructor couldn't be
    // determined while the class was being declared, force a declaration
    // of it now.
    if (ClassDecl->needsOverloadResolutionForCopyConstructor() ||
        ClassDecl->hasInheritedConstructor())
      DeclareImplicitCopyConstructor(ClassDecl);
    // For the MS ABI we need to know whether the copy ctor is deleted. A
    // prerequisite for deleting the implicit copy ctor is that the class has
    // a move ctor or move assignment that is either user-declared or whose
    // semantics are inherited from a subobject. FIXME: We should provide a
    // more direct way for CodeGen to ask whether the constructor was deleted.
    else if (Context.getTargetInfo().getCXXABI().isMicrosoft() &&
             (ClassDecl->hasUserDeclaredMoveConstructor() ||
              ClassDecl->needsOverloadResolutionForMoveConstructor() ||
              ClassDecl->hasUserDeclaredMoveAssignment() ||
              ClassDecl->needsOverloadResolutionForMoveAssignment()))
      DeclareImplicitCopyConstructor(ClassDecl);
  }

  if (getLangOpts().CPlusPlus11 &&
      ClassDecl->needsImplicitMoveConstructor()) {
    ++getASTContext().NumImplicitMoveConstructors;

    if (ClassDecl->needsOverloadResolutionForMoveConstructor() ||
        ClassDecl->hasInheritedConstructor())
      DeclareImplicitMoveConstructor(ClassDecl);
  }

  if (ClassDecl->needsImplicitCopyAssignment()) {
    ++getASTContext().NumImplicitCopyAssignmentOperators;

    // If we have a dynamic class, then the copy assignment operator may be
    // virtual, so we have to declare it immediately. This ensures that, e.g.,
    // it shows up in the right place in the vtable and that we diagnose
    // problems with the implicit exception specification.
    if (ClassDecl->isDynamicClass() ||
        ClassDecl->needsOverloadResolutionForCopyAssignment() ||
        ClassDecl->hasInheritedAssignment())
      DeclareImplicitCopyAssignment(ClassDecl);
  }

  if (getLangOpts().CPlusPlus11 && ClassDecl->needsImplicitMoveAssignment()) {
    ++getASTContext().NumImplicitMoveAssignmentOperators;

    // Likewise for the move assignment operator.
    if (ClassDecl->isDynamicClass() ||
        ClassDecl->needsOverloadResolutionForMoveAssignment() ||
        ClassDecl->hasInheritedAssignment())
      DeclareImplicitMoveAssignment(ClassDecl);
  }

  if (ClassDecl->needsImplicitDestructor()) {
    ++getASTContext().NumImplicitDestructors;

    // If we have a dynamic class, then the destructor may be virtual, so we
    // have to declare the destructor immediately. This ensures that, e.g., it
    // shows up in the right place in the vtable and that we diagnose problems
    // with the implicit exception specification.
    if (ClassDecl->isDynamicClass() ||
        ClassDecl->needsOverloadResolutionForDestructor())
      DeclareImplicitDestructor(ClassDecl);
  }
}

// C++2a [class.compare.default]p3:
//   If the member-specification does not explicitly declare any member or
//   friend named operator==, an == operator function is declared implicitly
//   for each defaulted three-way comparison operator function defined in
//   the member-specification
// FIXME: Consider doing this lazily.
// We do this during the initial parse for a class template, not during
// instantiation, so that we can handle unqualified lookups for 'operator=='
// when parsing the template.
if (getLangOpts().CPlusPlus20 && !inTemplateInstantiation()) {
  llvm::SmallVector<FunctionDecl *, 4> DefaultedSpaceships;
  findImplicitlyDeclaredEqualityComparisons(Context, ClassDecl,
                                            DefaultedSpaceships);
  for (auto *FD : DefaultedSpaceships)
    DeclareImplicitEqualityComparison(ClassDecl, FD);
}
10086}

10088unsigned
10089Sema::ActOnReenterTemplateScope(Decl *D,
                              llvm::function_ref<Scope *()> EnterScope) {
if (!D)
  return 0;
AdjustDeclIfTemplate(D);

// In order to get name lookup right, reenter template scopes in order from
// outermost to innermost.
SmallVector<TemplateParameterList *, 4> ParameterLists;
DeclContext *LookupDC = dyn_cast<DeclContext>(D);

if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
  for (unsigned i = 0; i < DD->getNumTemplateParameterLists(); ++i)
    ParameterLists.push_back(DD->getTemplateParameterList(i));

  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    if (FunctionTemplateDecl *FTD = FD->getDescribedFunctionTemplate())
      ParameterLists.push_back(FTD->getTemplateParameters());
  } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
    LookupDC = VD->getDeclContext();

    if (VarTemplateDecl *VTD = VD->getDescribedVarTemplate())
      ParameterLists.push_back(VTD->getTemplateParameters());
    else if (auto *PSD = dyn_cast<VarTemplatePartialSpecializationDecl>(D))
      ParameterLists.push_back(PSD->getTemplateParameters());
  }
} else if (TagDecl *TD = dyn_cast<TagDecl>(D)) {
  for (unsigned i = 0; i < TD->getNumTemplateParameterLists(); ++i)
    ParameterLists.push_back(TD->getTemplateParameterList(i));

  if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(TD)) {
    if (ClassTemplateDecl *CTD = RD->getDescribedClassTemplate())
      ParameterLists.push_back(CTD->getTemplateParameters());
    else if (auto *PSD = dyn_cast<ClassTemplatePartialSpecializationDecl>(D))
      ParameterLists.push_back(PSD->getTemplateParameters());
  }
}
// FIXME: Alias declarations and concepts.

unsigned Count = 0;
Scope *InnermostTemplateScope = nullptr;
for (TemplateParameterList *Params : ParameterLists) {
  // Ignore explicit specializations; they don't contribute to the template
  // depth.
  if (Params->size() == 0)
    continue;

  InnermostTemplateScope = EnterScope();
  for (NamedDecl *Param : *Params) {
    if (Param->getDeclName()) {
      InnermostTemplateScope->AddDecl(Param);
      IdResolver.AddDecl(Param);
    }
  }
  ++Count;
}

// Associate the new template scopes with the corresponding entities.
if (InnermostTemplateScope) {
  assert(LookupDC && "no enclosing DeclContext for template lookup")((void)0);
  EnterTemplatedContext(InnermostTemplateScope, LookupDC);
}

return Count;
10153}

10155void Sema::ActOnStartDelayedMemberDeclarations(Scope *S, Decl *RecordD) {
if (!RecordD) return;
AdjustDeclIfTemplate(RecordD);
CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordD);
PushDeclContext(S, Record);
10160}

10162void Sema::ActOnFinishDelayedMemberDeclarations(Scope *S, Decl *RecordD) {
if (!RecordD) return;
PopDeclContext();
10165}

10167/// This is used to implement the constant expression evaluation part of the
10168/// attribute enable_if extension. There is nothing in standard C++ which would
10169/// require reentering parameters.
10170void Sema::ActOnReenterCXXMethodParameter(Scope *S, ParmVarDecl *Param) {
if (!Param)
  return;

S->AddDecl(Param);
if (Param->getDeclName())
  IdResolver.AddDecl(Param);
10177}

10179/// ActOnStartDelayedCXXMethodDeclaration - We have completed
10180/// parsing a top-level (non-nested) C++ class, and we are now
10181/// parsing those parts of the given Method declaration that could
10182/// not be parsed earlier (C++ [class.mem]p2), such as default
10183/// arguments. This action should enter the scope of the given
10184/// Method declaration as if we had just parsed the qualified method
10185/// name. However, it should not bring the parameters into scope;
10186/// that will be performed by ActOnDelayedCXXMethodParameter.
10187void Sema::ActOnStartDelayedCXXMethodDeclaration(Scope *S, Decl *MethodD) {
10188}

10190/// ActOnDelayedCXXMethodParameter - We've already started a delayed
10191/// C++ method declaration. We're (re-)introducing the given
10192/// function parameter into scope for use in parsing later parts of
10193/// the method declaration. For example, we could see an
10194/// ActOnParamDefaultArgument event for this parameter.
10195void Sema::ActOnDelayedCXXMethodParameter(Scope *S, Decl *ParamD) {
if (!ParamD)
  return;

ParmVarDecl *Param = cast<ParmVarDecl>(ParamD);

S->AddDecl(Param);
if (Param->getDeclName())
  IdResolver.AddDecl(Param);
10204}

10206/// ActOnFinishDelayedCXXMethodDeclaration - We have finished
10207/// processing the delayed method declaration for Method. The method
10208/// declaration is now considered finished. There may be a separate
10209/// ActOnStartOfFunctionDef action later (not necessarily
10210/// immediately!) for this method, if it was also defined inside the
10211/// class body.
10212void Sema::ActOnFinishDelayedCXXMethodDeclaration(Scope *S, Decl *MethodD) {
if (!MethodD)
  return;

AdjustDeclIfTemplate(MethodD);

FunctionDecl *Method = cast<FunctionDecl>(MethodD);

// Now that we have our default arguments, check the constructor
// again. It could produce additional diagnostics or affect whether
// the class has implicitly-declared destructors, among other
// things.
if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Method))
  CheckConstructor(Constructor);

// Check the default arguments, which we may have added.
if (!Method->isInvalidDecl())
  CheckCXXDefaultArguments(Method);
10230}

10232// Emit the given diagnostic for each non-address-space qualifier.
10233// Common part of CheckConstructorDeclarator and CheckDestructorDeclarator.
10234static void checkMethodTypeQualifiers(Sema &S, Declarator &D, unsigned DiagID) {
const DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
if (FTI.hasMethodTypeQualifiers() && !D.isInvalidType()) {
  bool DiagOccured = false;
  FTI.MethodQualifiers->forEachQualifier(
      [DiagID, &S, &DiagOccured](DeclSpec::TQ, StringRef QualName,
                                 SourceLocation SL) {
        // This diagnostic should be emitted on any qualifier except an addr
        // space qualifier. However, forEachQualifier currently doesn't visit
        // addr space qualifiers, so there's no way to write this condition
        // right now; we just diagnose on everything.
        S.Diag(SL, DiagID) << QualName << SourceRange(SL);
        DiagOccured = true;
      });
  if (DiagOccured)
    D.setInvalidType();
}
10251}

10253/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
10254/// the well-formedness of the constructor declarator @p D with type @p
10255/// R. If there are any errors in the declarator, this routine will
10256/// emit diagnostics and set the invalid bit to true.  In any case, the type
10257/// will be updated to reflect a well-formed type for the constructor and
10258/// returned.
10259QualType Sema::CheckConstructorDeclarator(Declarator &D, QualType R,
                                        StorageClass &SC) {
bool isVirtual = D.getDeclSpec().isVirtualSpecified();

// C++ [class.ctor]p3:
//   A constructor shall not be virtual (10.3) or static (9.4). A
//   constructor can be invoked for a const, volatile or const
//   volatile object. A constructor shall not be declared const,
//   volatile, or const volatile (9.3.2).
if (isVirtual) {
  if (!D.isInvalidType())
    Diag(D.getIdentifierLoc(), diag::err_constructor_cannot_be)
      << "virtual" << SourceRange(D.getDeclSpec().getVirtualSpecLoc())
      << SourceRange(D.getIdentifierLoc());
  D.setInvalidType();
}
if (SC == SC_Static) {
  if (!D.isInvalidType())
    Diag(D.getIdentifierLoc(), diag::err_constructor_cannot_be)
      << "static" << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
      << SourceRange(D.getIdentifierLoc());
  D.setInvalidType();
  SC = SC_None;
}

if (unsigned TypeQuals = D.getDeclSpec().getTypeQualifiers()) {
  diagnoseIgnoredQualifiers(
      diag::err_constructor_return_type, TypeQuals, SourceLocation(),
      D.getDeclSpec().getConstSpecLoc(), D.getDeclSpec().getVolatileSpecLoc(),
      D.getDeclSpec().getRestrictSpecLoc(),
      D.getDeclSpec().getAtomicSpecLoc());
  D.setInvalidType();
}

checkMethodTypeQualifiers(*this, D, diag::err_invalid_qualified_constructor);

// C++0x [class.ctor]p4:
//   A constructor shall not be declared with a ref-qualifier.
DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
if (FTI.hasRefQualifier()) {
  Diag(FTI.getRefQualifierLoc(), diag::err_ref_qualifier_constructor)
    << FTI.RefQualifierIsLValueRef
    << FixItHint::CreateRemoval(FTI.getRefQualifierLoc());
  D.setInvalidType();
}

// Rebuild the function type "R" without any type qualifiers (in
// case any of the errors above fired) and with "void" as the
// return type, since constructors don't have return types.
const FunctionProtoType *Proto = R->castAs<FunctionProtoType>();
if (Proto->getReturnType() == Context.VoidTy && !D.isInvalidType())
  return R;

FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
EPI.TypeQuals = Qualifiers();
EPI.RefQualifier = RQ_None;

return Context.getFunctionType(Context.VoidTy, Proto->getParamTypes(), EPI);
10317}

10319/// CheckConstructor - Checks a fully-formed constructor for
10320/// well-formedness, issuing any diagnostics required. Returns true if
10321/// the constructor declarator is invalid.
10322void Sema::CheckConstructor(CXXConstructorDecl *Constructor) {
CXXRecordDecl *ClassDecl
  = dyn_cast<CXXRecordDecl>(Constructor->getDeclContext());
if (!ClassDecl)
  return Constructor->setInvalidDecl();

// C++ [class.copy]p3:
//   A declaration of a constructor for a class X is ill-formed if
//   its first parameter is of type (optionally cv-qualified) X and
//   either there are no other parameters or else all other
//   parameters have default arguments.
if (!Constructor->isInvalidDecl() &&
    Constructor->hasOneParamOrDefaultArgs() &&
    Constructor->getTemplateSpecializationKind() !=
        TSK_ImplicitInstantiation) {
  QualType ParamType = Constructor->getParamDecl(0)->getType();
  QualType ClassTy = Context.getTagDeclType(ClassDecl);
  if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) {
    SourceLocation ParamLoc = Constructor->getParamDecl(0)->getLocation();
    const char *ConstRef
      = Constructor->getParamDecl(0)->getIdentifier() ? "const &"
                                                      : " const &";
    Diag(ParamLoc, diag::err_constructor_byvalue_arg)
      << FixItHint::CreateInsertion(ParamLoc, ConstRef);

    // FIXME: Rather that making the constructor invalid, we should endeavor
    // to fix the type.
    Constructor->setInvalidDecl();
  }
}
10352}

10354/// CheckDestructor - Checks a fully-formed destructor definition for
10355/// well-formedness, issuing any diagnostics required.  Returns true
10356/// on error.
10357bool Sema::CheckDestructor(CXXDestructorDecl *Destructor) {
CXXRecordDecl *RD = Destructor->getParent();

if (!Destructor->getOperatorDelete() && Destructor->isVirtual()) {
  SourceLocation Loc;

  if (!Destructor->isImplicit())
    Loc = Destructor->getLocation();
  else
    Loc = RD->getLocation();

  // If we have a virtual destructor, look up the deallocation function
  if (FunctionDecl *OperatorDelete =
          FindDeallocationFunctionForDestructor(Loc, RD)) {
    Expr *ThisArg = nullptr;

    // If the notional 'delete this' expression requires a non-trivial
    // conversion from 'this' to the type of a destroying operator delete's
    // first parameter, perform that conversion now.
    if (OperatorDelete->isDestroyingOperatorDelete()) {
      QualType ParamType = OperatorDelete->getParamDecl(0)->getType();
      if (!declaresSameEntity(ParamType->getAsCXXRecordDecl(), RD)) {
        // C++ [class.dtor]p13:
        //   ... as if for the expression 'delete this' appearing in a
        //   non-virtual destructor of the destructor's class.
        ContextRAII SwitchContext(*this, Destructor);
        ExprResult This =
            ActOnCXXThis(OperatorDelete->getParamDecl(0)->getLocation());
        assert(!This.isInvalid() && "couldn't form 'this' expr in dtor?")((void)0);
        This = PerformImplicitConversion(This.get(), ParamType, AA_Passing);
        if (This.isInvalid()) {
          // FIXME: Register this as a context note so that it comes out
          // in the right order.
          Diag(Loc, diag::note_implicit_delete_this_in_destructor_here);
          return true;
        }
        ThisArg = This.get();
      }
    }

    DiagnoseUseOfDecl(OperatorDelete, Loc);
    MarkFunctionReferenced(Loc, OperatorDelete);
    Destructor->setOperatorDelete(OperatorDelete, ThisArg);
  }
}

return false;
10404}

10406/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
10407/// the well-formednes of the destructor declarator @p D with type @p
10408/// R. If there are any errors in the declarator, this routine will
10409/// emit diagnostics and set the declarator to invalid.  Even if this happens,
10410/// will be updated to reflect a well-formed type for the destructor and
10411/// returned.
10412QualType Sema::CheckDestructorDeclarator(Declarator &D, QualType R,
                                       StorageClass& SC) {
// C++ [class.dtor]p1:
//   [...] A typedef-name that names a class is a class-name
//   (7.1.3); however, a typedef-name that names a class shall not
//   be used as the identifier in the declarator for a destructor
//   declaration.
QualType DeclaratorType = GetTypeFromParser(D.getName().DestructorName);
if (const TypedefType *TT = DeclaratorType->getAs<TypedefType>())
  Diag(D.getIdentifierLoc(), diag::ext_destructor_typedef_name)
    << DeclaratorType << isa<TypeAliasDecl>(TT->getDecl());
else if (const TemplateSpecializationType *TST =
           DeclaratorType->getAs<TemplateSpecializationType>())
  if (TST->isTypeAlias())
    Diag(D.getIdentifierLoc(), diag::ext_destructor_typedef_name)
      << DeclaratorType << 1;

// C++ [class.dtor]p2:
//   A destructor is used to destroy objects of its class type. A
//   destructor takes no parameters, and no return type can be
//   specified for it (not even void). The address of a destructor
//   shall not be taken. A destructor shall not be static. A
//   destructor can be invoked for a const, volatile or const
//   volatile object. A destructor shall not be declared const,
//   volatile or const volatile (9.3.2).
if (SC == SC_Static) {
  if (!D.isInvalidType())
    Diag(D.getIdentifierLoc(), diag::err_destructor_cannot_be)
      << "static" << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
      << SourceRange(D.getIdentifierLoc())
      << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());

  SC = SC_None;
}
if (!D.isInvalidType()) {
  // Destructors don't have return types, but the parser will
  // happily parse something like:
  //
  //   class X {
  //     float ~X();
  //   };
  //
  // The return type will be eliminated later.
  if (D.getDeclSpec().hasTypeSpecifier())
    Diag(D.getIdentifierLoc(), diag::err_destructor_return_type)
      << SourceRange(D.getDeclSpec().getTypeSpecTypeLoc())
      << SourceRange(D.getIdentifierLoc());
  else if (unsigned TypeQuals = D.getDeclSpec().getTypeQualifiers()) {
    diagnoseIgnoredQualifiers(diag::err_destructor_return_type, TypeQuals,
                              SourceLocation(),
                              D.getDeclSpec().getConstSpecLoc(),
                              D.getDeclSpec().getVolatileSpecLoc(),
                              D.getDeclSpec().getRestrictSpecLoc(),
                              D.getDeclSpec().getAtomicSpecLoc());
    D.setInvalidType();
  }
}

checkMethodTypeQualifiers(*this, D, diag::err_invalid_qualified_destructor);

// C++0x [class.dtor]p2:
//   A destructor shall not be declared with a ref-qualifier.
DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
if (FTI.hasRefQualifier()) {
  Diag(FTI.getRefQualifierLoc(), diag::err_ref_qualifier_destructor)
    << FTI.RefQualifierIsLValueRef
    << FixItHint::CreateRemoval(FTI.getRefQualifierLoc());
  D.setInvalidType();
}

// Make sure we don't have any parameters.
if (FTIHasNonVoidParameters(FTI)) {
  Diag(D.getIdentifierLoc(), diag::err_destructor_with_params);

  // Delete the parameters.
  FTI.freeParams();
  D.setInvalidType();
}

// Make sure the destructor isn't variadic.
if (FTI.isVariadic) {
  Diag(D.getIdentifierLoc(), diag::err_destructor_variadic);
  D.setInvalidType();
}

// Rebuild the function type "R" without any type qualifiers or
// parameters (in case any of the errors above fired) and with
// "void" as the return type, since destructors don't have return
// types.
if (!D.isInvalidType())
  return R;

const FunctionProtoType *Proto = R->castAs<FunctionProtoType>();
FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
EPI.Variadic = false;
EPI.TypeQuals = Qualifiers();
EPI.RefQualifier = RQ_None;
return Context.getFunctionType(Context.VoidTy, None, EPI);
10510}

10512static void extendLeft(SourceRange &R, SourceRange Before) {
if (Before.isInvalid())
  return;
R.setBegin(Before.getBegin());
if (R.getEnd().isInvalid())
  R.setEnd(Before.getEnd());
10518}

10520static void extendRight(SourceRange &R, SourceRange After) {
if (After.isInvalid())
  return;
if (R.getBegin().isInvalid())
  R.setBegin(After.getBegin());
R.setEnd(After.getEnd());
10526}

10528/// CheckConversionDeclarator - Called by ActOnDeclarator to check the
10529/// well-formednes of the conversion function declarator @p D with
10530/// type @p R. If there are any errors in the declarator, this routine
10531/// will emit diagnostics and return true. Otherwise, it will return
10532/// false. Either way, the type @p R will be updated to reflect a
10533/// well-formed type for the conversion operator.
10534void Sema::CheckConversionDeclarator(Declarator &D, QualType &R,
                                   StorageClass& SC) {
// C++ [class.conv.fct]p1:
//   Neither parameter types nor return type can be specified. The
//   type of a conversion function (8.3.5) is "function taking no
//   parameter returning conversion-type-id."
if (SC == SC_Static) {
  if (!D.isInvalidType())
    Diag(D.getIdentifierLoc(), diag::err_conv_function_not_member)
      << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
      << D.getName().getSourceRange();
  D.setInvalidType();
  SC = SC_None;
}

TypeSourceInfo *ConvTSI = nullptr;
QualType ConvType =
    GetTypeFromParser(D.getName().ConversionFunctionId, &ConvTSI);

const DeclSpec &DS = D.getDeclSpec();
if (DS.hasTypeSpecifier() && !D.isInvalidType()) {
  // Conversion functions don't have return types, but the parser will
  // happily parse something like:
  //
  //   class X {
  //     float operator bool();
  //   };
  //
  // The return type will be changed later anyway.
  Diag(D.getIdentifierLoc(), diag::err_conv_function_return_type)
    << SourceRange(DS.getTypeSpecTypeLoc())
    << SourceRange(D.getIdentifierLoc());
  D.setInvalidType();
} else if (DS.getTypeQualifiers() && !D.isInvalidType()) {
  // It's also plausible that the user writes type qualifiers in the wrong
  // place, such as:
  //   struct S { const operator int(); };
  // FIXME: we could provide a fixit to move the qualifiers onto the
  // conversion type.
  Diag(D.getIdentifierLoc(), diag::err_conv_function_with_complex_decl)
      << SourceRange(D.getIdentifierLoc()) << 0;
  D.setInvalidType();
}

const auto *Proto = R->castAs<FunctionProtoType>();

// Make sure we don't have any parameters.
if (Proto->getNumParams() > 0) {
  Diag(D.getIdentifierLoc(), diag::err_conv_function_with_params);

  // Delete the parameters.
  D.getFunctionTypeInfo().freeParams();
  D.setInvalidType();
} else if (Proto->isVariadic()) {
  Diag(D.getIdentifierLoc(), diag::err_conv_function_variadic);
  D.setInvalidType();
}

// Diagnose "&operator bool()" and other such nonsense.  This
// is actually a gcc extension which we don't support.
if (Proto->getReturnType() != ConvType) {
  bool NeedsTypedef = false;
  SourceRange Before, After;

  // Walk the chunks and extract information on them for our diagnostic.
  bool PastFunctionChunk = false;
  for (auto &Chunk : D.type_objects()) {
    switch (Chunk.Kind) {
    case DeclaratorChunk::Function:
      if (!PastFunctionChunk) {
        if (Chunk.Fun.HasTrailingReturnType) {
          TypeSourceInfo *TRT = nullptr;
          GetTypeFromParser(Chunk.Fun.getTrailingReturnType(), &TRT);
          if (TRT) extendRight(After, TRT->getTypeLoc().getSourceRange());
        }
        PastFunctionChunk = true;
        break;
      }
      LLVM_FALLTHROUGH[[gnu::fallthrough]];
    case DeclaratorChunk::Array:
      NeedsTypedef = true;
      extendRight(After, Chunk.getSourceRange());
      break;

    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      extendLeft(Before, Chunk.getSourceRange());
      break;

    case DeclaratorChunk::Paren:
      extendLeft(Before, Chunk.Loc);
      extendRight(After, Chunk.EndLoc);
      break;
    }
  }

  SourceLocation Loc = Before.isValid() ? Before.getBegin() :
                       After.isValid()  ? After.getBegin() :
                                          D.getIdentifierLoc();
  auto &&DB = Diag(Loc, diag::err_conv_function_with_complex_decl);
  DB << Before << After;

  if (!NeedsTypedef) {
    DB << /*don't need a typedef*/0;

    // If we can provide a correct fix-it hint, do so.
    if (After.isInvalid() && ConvTSI) {
      SourceLocation InsertLoc =
          getLocForEndOfToken(ConvTSI->getTypeLoc().getEndLoc());
      DB << FixItHint::CreateInsertion(InsertLoc, " ")
         << FixItHint::CreateInsertionFromRange(
                InsertLoc, CharSourceRange::getTokenRange(Before))
         << FixItHint::CreateRemoval(Before);
    }
  } else if (!Proto->getReturnType()->isDependentType()) {
    DB << /*typedef*/1 << Proto->getReturnType();
  } else if (getLangOpts().CPlusPlus11) {
    DB << /*alias template*/2 << Proto->getReturnType();
  } else {
    DB << /*might not be fixable*/3;
  }

  // Recover by incorporating the other type chunks into the result type.
  // Note, this does *not* change the name of the function. This is compatible
  // with the GCC extension:
  //   struct S { &operator int(); } s;
  //   int &r = s.operator int(); // ok in GCC
  //   S::operator int&() {} // error in GCC, function name is 'operator int'.
  ConvType = Proto->getReturnType();
}

// C++ [class.conv.fct]p4:
//   The conversion-type-id shall not represent a function type nor
//   an array type.
if (ConvType->isArrayType()) {
  Diag(D.getIdentifierLoc(), diag::err_conv_function_to_array);
  ConvType = Context.getPointerType(ConvType);
  D.setInvalidType();
} else if (ConvType->isFunctionType()) {
  Diag(D.getIdentifierLoc(), diag::err_conv_function_to_function);
  ConvType = Context.getPointerType(ConvType);
  D.setInvalidType();
}

// Rebuild the function type "R" without any parameters (in case any
// of the errors above fired) and with the conversion type as the
// return type.
if (D.isInvalidType())
  R = Context.getFunctionType(ConvType, None, Proto->getExtProtoInfo());

// C++0x explicit conversion operators.
if (DS.hasExplicitSpecifier() && !getLangOpts().CPlusPlus20)
  Diag(DS.getExplicitSpecLoc(),
       getLangOpts().CPlusPlus11
           ? diag::warn_cxx98_compat_explicit_conversion_functions
           : diag::ext_explicit_conversion_functions)
      << SourceRange(DS.getExplicitSpecRange());
10694}

10696/// ActOnConversionDeclarator - Called by ActOnDeclarator to complete
10697/// the declaration of the given C++ conversion function. This routine
10698/// is responsible for recording the conversion function in the C++
10699/// class, if possible.
10700Decl *Sema::ActOnConversionDeclarator(CXXConversionDecl *Conversion) {
assert(Conversion && "Expected to receive a conversion function declaration")((void)0);

CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Conversion->getDeclContext());

// Make sure we aren't redeclaring the conversion function.
QualType ConvType = Context.getCanonicalType(Conversion->getConversionType());
// C++ [class.conv.fct]p1:
//   [...] A conversion function is never used to convert a
//   (possibly cv-qualified) object to the (possibly cv-qualified)
//   same object type (or a reference to it), to a (possibly
//   cv-qualified) base class of that type (or a reference to it),
//   or to (possibly cv-qualified) void.
QualType ClassType
  = Context.getCanonicalType(Context.getTypeDeclType(ClassDecl));
if (const ReferenceType *ConvTypeRef = ConvType->getAs<ReferenceType>())
  ConvType = ConvTypeRef->getPointeeType();
if (Conversion->getTemplateSpecializationKind() != TSK_Undeclared &&
    Conversion->getTemplateSpecializationKind() != TSK_ExplicitSpecialization)
  /* Suppress diagnostics for instantiations. */;
else if (Conversion->size_overridden_methods() != 0)
  /* Suppress diagnostics for overriding virtual function in a base class. */;
else if (ConvType->isRecordType()) {
  ConvType = Context.getCanonicalType(ConvType).getUnqualifiedType();
  if (ConvType == ClassType)
    Diag(Conversion->getLocation(), diag::warn_conv_to_self_not_used)
      << ClassType;
  else if (IsDerivedFrom(Conversion->getLocation(), ClassType, ConvType))
    Diag(Conversion->getLocation(), diag::warn_conv_to_base_not_used)
      <<  ClassType << ConvType;
} else if (ConvType->isVoidType()) {
  Diag(Conversion->getLocation(), diag::warn_conv_to_void_not_used)
    << ClassType << ConvType;
}

if (FunctionTemplateDecl *ConversionTemplate
                              = Conversion->getDescribedFunctionTemplate())
  return ConversionTemplate;

return Conversion;
10740}

10742namespace {
10743/// Utility class to accumulate and print a diagnostic listing the invalid
10744/// specifier(s) on a declaration.
10745struct BadSpecifierDiagnoser {
BadSpecifierDiagnoser(Sema &S, SourceLocation Loc, unsigned DiagID)
    : S(S), Diagnostic(S.Diag(Loc, DiagID)) {}
~BadSpecifierDiagnoser() {
  Diagnostic << Specifiers;
}

template<typename T> void check(SourceLocation SpecLoc, T Spec) {
  return check(SpecLoc, DeclSpec::getSpecifierName(Spec));
}
void check(SourceLocation SpecLoc, DeclSpec::TST Spec) {
  return check(SpecLoc,
               DeclSpec::getSpecifierName(Spec, S.getPrintingPolicy()));
}
void check(SourceLocation SpecLoc, const char *Spec) {
  if (SpecLoc.isInvalid()) return;
  Diagnostic << SourceRange(SpecLoc, SpecLoc);
  if (!Specifiers.empty()) Specifiers += " ";
  Specifiers += Spec;
}

Sema &S;
Sema::SemaDiagnosticBuilder Diagnostic;
std::string Specifiers;
10769};
10770}

10772/// Check the validity of a declarator that we parsed for a deduction-guide.
10773/// These aren't actually declarators in the grammar, so we need to check that
10774/// the user didn't specify any pieces that are not part of the deduction-guide
10775/// grammar.
10776void Sema::CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
                                       StorageClass &SC) {
TemplateName GuidedTemplate = D.getName().TemplateName.get().get();
TemplateDecl *GuidedTemplateDecl = GuidedTemplate.getAsTemplateDecl();
assert(GuidedTemplateDecl && "missing template decl for deduction guide")((void)0);

// C++ [temp.deduct.guide]p3:
//   A deduction-gide shall be declared in the same scope as the
//   corresponding class template.
if (!CurContext->getRedeclContext()->Equals(
        GuidedTemplateDecl->getDeclContext()->getRedeclContext())) {
  Diag(D.getIdentifierLoc(), diag::err_deduction_guide_wrong_scope)
    << GuidedTemplateDecl;
  Diag(GuidedTemplateDecl->getLocation(), diag::note_template_decl_here);
}

auto &DS = D.getMutableDeclSpec();
// We leave 'friend' and 'virtual' to be rejected in the normal way.
if (DS.hasTypeSpecifier() || DS.getTypeQualifiers() ||
    DS.getStorageClassSpecLoc().isValid() || DS.isInlineSpecified() ||
    DS.isNoreturnSpecified() || DS.hasConstexprSpecifier()) {
  BadSpecifierDiagnoser Diagnoser(
      *this, D.getIdentifierLoc(),
      diag::err_deduction_guide_invalid_specifier);

  Diagnoser.check(DS.getStorageClassSpecLoc(), DS.getStorageClassSpec());
  DS.ClearStorageClassSpecs();
  SC = SC_None;

  // 'explicit' is permitted.
  Diagnoser.check(DS.getInlineSpecLoc(), "inline");
  Diagnoser.check(DS.getNoreturnSpecLoc(), "_Noreturn");
  Diagnoser.check(DS.getConstexprSpecLoc(), "constexpr");
  DS.ClearConstexprSpec();

  Diagnoser.check(DS.getConstSpecLoc(), "const");
  Diagnoser.check(DS.getRestrictSpecLoc(), "__restrict");
  Diagnoser.check(DS.getVolatileSpecLoc(), "volatile");
  Diagnoser.check(DS.getAtomicSpecLoc(), "_Atomic");
  Diagnoser.check(DS.getUnalignedSpecLoc(), "__unaligned");
  DS.ClearTypeQualifiers();

  Diagnoser.check(DS.getTypeSpecComplexLoc(), DS.getTypeSpecComplex());
  Diagnoser.check(DS.getTypeSpecSignLoc(), DS.getTypeSpecSign());
  Diagnoser.check(DS.getTypeSpecWidthLoc(), DS.getTypeSpecWidth());
  Diagnoser.check(DS.getTypeSpecTypeLoc(), DS.getTypeSpecType());
  DS.ClearTypeSpecType();
}

if (D.isInvalidType())
  return;

// Check the declarator is simple enough.
bool FoundFunction = false;
for (const DeclaratorChunk &Chunk : llvm::reverse(D.type_objects())) {
  if (Chunk.Kind == DeclaratorChunk::Paren)
    continue;
  if (Chunk.Kind != DeclaratorChunk::Function || FoundFunction) {
    Diag(D.getDeclSpec().getBeginLoc(),
         diag::err_deduction_guide_with_complex_decl)
        << D.getSourceRange();
    break;
  }
  if (!Chunk.Fun.hasTrailingReturnType()) {
    Diag(D.getName().getBeginLoc(),
         diag::err_deduction_guide_no_trailing_return_type);
    break;
  }

  // Check that the return type is written as a specialization of
  // the template specified as the deduction-guide's name.
  ParsedType TrailingReturnType = Chunk.Fun.getTrailingReturnType();
  TypeSourceInfo *TSI = nullptr;
  QualType RetTy = GetTypeFromParser(TrailingReturnType, &TSI);
  assert(TSI && "deduction guide has valid type but invalid return type?")((void)0);
  bool AcceptableReturnType = false;
  bool MightInstantiateToSpecialization = false;
  if (auto RetTST =
          TSI->getTypeLoc().getAs<TemplateSpecializationTypeLoc>()) {
    TemplateName SpecifiedName = RetTST.getTypePtr()->getTemplateName();
    bool TemplateMatches =
        Context.hasSameTemplateName(SpecifiedName, GuidedTemplate);
    if (SpecifiedName.getKind() == TemplateName::Template && TemplateMatches)
      AcceptableReturnType = true;
    else {
      // This could still instantiate to the right type, unless we know it
      // names the wrong class template.
      auto *TD = SpecifiedName.getAsTemplateDecl();
      MightInstantiateToSpecialization = !(TD && isa<ClassTemplateDecl>(TD) &&
                                           !TemplateMatches);
    }
  } else if (!RetTy.hasQualifiers() && RetTy->isDependentType()) {
    MightInstantiateToSpecialization = true;
  }

  if (!AcceptableReturnType) {
    Diag(TSI->getTypeLoc().getBeginLoc(),
         diag::err_deduction_guide_bad_trailing_return_type)
        << GuidedTemplate << TSI->getType()
        << MightInstantiateToSpecialization
        << TSI->getTypeLoc().getSourceRange();
  }

  // Keep going to check that we don't have any inner declarator pieces (we
  // could still have a function returning a pointer to a function).
  FoundFunction = true;
}

if (D.isFunctionDefinition())
  Diag(D.getIdentifierLoc(), diag::err_deduction_guide_defines_function);
10886}

10888//===----------------------------------------------------------------------===//
10889// Namespace Handling
10890//===----------------------------------------------------------------------===//

10892/// Diagnose a mismatch in 'inline' qualifiers when a namespace is
10893/// reopened.
10894static void DiagnoseNamespaceInlineMismatch(Sema &S, SourceLocation KeywordLoc,
                                          SourceLocation Loc,
                                          IdentifierInfo *II, bool *IsInline,
                                          NamespaceDecl *PrevNS) {
assert(*IsInline != PrevNS->isInline())((void)0);

if (PrevNS->isInline())
  // The user probably just forgot the 'inline', so suggest that it
  // be added back.
  S.Diag(Loc, diag::warn_inline_namespace_reopened_noninline)
    << FixItHint::CreateInsertion(KeywordLoc, "inline ");
else
  S.Diag(Loc, diag::err_inline_namespace_mismatch);

S.Diag(PrevNS->getLocation(), diag::note_previous_definition);
*IsInline = PrevNS->isInline();
10910}

10912/// ActOnStartNamespaceDef - This is called at the start of a namespace
10913/// definition.
10914Decl *Sema::ActOnStartNamespaceDef(
  Scope *NamespcScope, SourceLocation InlineLoc, SourceLocation NamespaceLoc,
  SourceLocation IdentLoc, IdentifierInfo *II, SourceLocation LBrace,
  const ParsedAttributesView &AttrList, UsingDirectiveDecl *&UD) {
SourceLocation StartLoc = InlineLoc.isValid() ? InlineLoc : NamespaceLoc;
// For anonymous namespace, take the location of the left brace.
SourceLocation Loc = II ? IdentLoc : LBrace;
bool IsInline = InlineLoc.isValid();
bool IsInvalid = false;
bool IsStd = false;
bool AddToKnown = false;
Scope *DeclRegionScope = NamespcScope->getParent();

NamespaceDecl *PrevNS = nullptr;
if (II) {
  // C++ [namespace.def]p2:
  //   The identifier in an original-namespace-definition shall not
  //   have been previously defined in the declarative region in
  //   which the original-namespace-definition appears. The
  //   identifier in an original-namespace-definition is the name of
  //   the namespace. Subsequently in that declarative region, it is
  //   treated as an original-namespace-name.
  //
  // Since namespace names are unique in their scope, and we don't
  // look through using directives, just look for any ordinary names
  // as if by qualified name lookup.
  LookupResult R(*this, II, IdentLoc, LookupOrdinaryName,
                 ForExternalRedeclaration);
  LookupQualifiedName(R, CurContext->getRedeclContext());
  NamedDecl *PrevDecl =
      R.isSingleResult() ? R.getRepresentativeDecl() : nullptr;
  PrevNS = dyn_cast_or_null<NamespaceDecl>(PrevDecl);

  if (PrevNS) {
    // This is an extended namespace definition.
    if (IsInline != PrevNS->isInline())
      DiagnoseNamespaceInlineMismatch(*this, NamespaceLoc, Loc, II,
                                      &IsInline, PrevNS);
  } else if (PrevDecl) {
    // This is an invalid name redefinition.
    Diag(Loc, diag::err_redefinition_different_kind)
      << II;
    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
    IsInvalid = true;
    // Continue on to push Namespc as current DeclContext and return it.
  } else if (II->isStr("std") &&
             CurContext->getRedeclContext()->isTranslationUnit()) {
    // This is the first "real" definition of the namespace "std", so update
    // our cache of the "std" namespace to point at this definition.
    PrevNS = getStdNamespace();
    IsStd = true;
    AddToKnown = !IsInline;
  } else {
    // We've seen this namespace for the first time.
    AddToKnown = !IsInline;
  }
} else {
  // Anonymous namespaces.

  // Determine whether the parent already has an anonymous namespace.
  DeclContext *Parent = CurContext->getRedeclContext();
  if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(Parent)) {
    PrevNS = TU->getAnonymousNamespace();
  } else {
    NamespaceDecl *ND = cast<NamespaceDecl>(Parent);
    PrevNS = ND->getAnonymousNamespace();
  }

  if (PrevNS && IsInline != PrevNS->isInline())
    DiagnoseNamespaceInlineMismatch(*this, NamespaceLoc, NamespaceLoc, II,
                                    &IsInline, PrevNS);
}

NamespaceDecl *Namespc = NamespaceDecl::Create(Context, CurContext, IsInline,
                                               StartLoc, Loc, II, PrevNS);
if (IsInvalid)
  Namespc->setInvalidDecl();

ProcessDeclAttributeList(DeclRegionScope, Namespc, AttrList);
AddPragmaAttributes(DeclRegionScope, Namespc);

// FIXME: Should we be merging attributes?
if (const VisibilityAttr *Attr = Namespc->getAttr<VisibilityAttr>())
  PushNamespaceVisibilityAttr(Attr, Loc);

if (IsStd)
  StdNamespace = Namespc;
if (AddToKnown)
  KnownNamespaces[Namespc] = false;

if (II) {
  PushOnScopeChains(Namespc, DeclRegionScope);
} else {
  // Link the anonymous namespace into its parent.
  DeclContext *Parent = CurContext->getRedeclContext();
  if (TranslationUnitDecl *TU = dyn_cast<TranslationUnitDecl>(Parent)) {
    TU->setAnonymousNamespace(Namespc);
  } else {
    cast<NamespaceDecl>(Parent)->setAnonymousNamespace(Namespc);
  }

  CurContext->addDecl(Namespc);

  // C++ [namespace.unnamed]p1.  An unnamed-namespace-definition
  //   behaves as if it were replaced by
  //     namespace unique { /* empty body */ }
  //     using namespace unique;
  //     namespace unique { namespace-body }
  //   where all occurrences of 'unique' in a translation unit are
  //   replaced by the same identifier and this identifier differs
  //   from all other identifiers in the entire program.

  // We just create the namespace with an empty name and then add an
  // implicit using declaration, just like the standard suggests.
  //
  // CodeGen enforces the "universally unique" aspect by giving all
  // declarations semantically contained within an anonymous
  // namespace internal linkage.

  if (!PrevNS) {
    UD = UsingDirectiveDecl::Create(Context, Parent,
                                    /* 'using' */ LBrace,
                                    /* 'namespace' */ SourceLocation(),
                                    /* qualifier */ NestedNameSpecifierLoc(),
                                    /* identifier */ SourceLocation(),
                                    Namespc,
                                    /* Ancestor */ Parent);
    UD->setImplicit();
    Parent->addDecl(UD);
  }
}

ActOnDocumentableDecl(Namespc);

// Although we could have an invalid decl (i.e. the namespace name is a
// redefinition), push it as current DeclContext and try to continue parsing.
// FIXME: We should be able to push Namespc here, so that the each DeclContext
// for the namespace has the declarations that showed up in that particular
// namespace definition.
PushDeclContext(NamespcScope, Namespc);
return Namespc;
11055}

11057/// getNamespaceDecl - Returns the namespace a decl represents. If the decl
11058/// is a namespace alias, returns the namespace it points to.
11059static inline NamespaceDecl *getNamespaceDecl(NamedDecl *D) {
if (NamespaceAliasDecl *AD = dyn_cast_or_null<NamespaceAliasDecl>(D))
  return AD->getNamespace();
return dyn_cast_or_null<NamespaceDecl>(D);
11063}

11065/// ActOnFinishNamespaceDef - This callback is called after a namespace is
11066/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef.
11067void Sema::ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace) {
NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl);
assert(Namespc && "Invalid parameter, expected NamespaceDecl")((void)0);
Namespc->setRBraceLoc(RBrace);
PopDeclContext();
if (Namespc->hasAttr<VisibilityAttr>())
  PopPragmaVisibility(true, RBrace);
// If this namespace contains an export-declaration, export it now.
if (DeferredExportedNamespaces.erase(Namespc))
  Dcl->setModuleOwnershipKind(Decl::ModuleOwnershipKind::VisibleWhenImported);
11077}

11079CXXRecordDecl *Sema::getStdBadAlloc() const {
return cast_or_null<CXXRecordDecl>(
                                StdBadAlloc.get(Context.getExternalSource()));
11082}

11084EnumDecl *Sema::getStdAlignValT() const {
return cast_or_null<EnumDecl>(StdAlignValT.get(Context.getExternalSource()));
11086}

11088NamespaceDecl *Sema::getStdNamespace() const {
return cast_or_null<NamespaceDecl>(
                               StdNamespace.get(Context.getExternalSource()));
11091}

11093NamespaceDecl *Sema::lookupStdExperimentalNamespace() {
if (!StdExperimentalNamespaceCache) {
  if (auto Std = getStdNamespace()) {
    LookupResult Result(*this, &PP.getIdentifierTable().get("experimental"),
                        SourceLocation(), LookupNamespaceName);
    if (!LookupQualifiedName(Result, Std) ||
        !(StdExperimentalNamespaceCache =
              Result.getAsSingle<NamespaceDecl>()))
      Result.suppressDiagnostics();
  }
}
return StdExperimentalNamespaceCache;
11105}

11107namespace {

11109enum UnsupportedSTLSelect {
USS_InvalidMember,
USS_MissingMember,
USS_NonTrivial,
USS_Other
11114};

11116struct InvalidSTLDiagnoser {
Sema &S;
SourceLocation Loc;
QualType TyForDiags;

QualType operator()(UnsupportedSTLSelect Sel = USS_Other, StringRef Name = "",
                    const VarDecl *VD = nullptr) {
  {
    auto D = S.Diag(Loc, diag::err_std_compare_type_not_supported)
             << TyForDiags << ((int)Sel);
    if (Sel == USS_InvalidMember || Sel == USS_MissingMember) {
      assert(!Name.empty())((void)0);
      D << Name;
    }
  }
  if (Sel == USS_InvalidMember) {
    S.Diag(VD->getLocation(), diag::note_var_declared_here)
        << VD << VD->getSourceRange();
  }
  return QualType();
}
11137};
11138} // namespace

11140QualType Sema::CheckComparisonCategoryType(ComparisonCategoryType Kind,
                                         SourceLocation Loc,
                                         ComparisonCategoryUsage Usage) {
assert(getLangOpts().CPlusPlus &&((void)0)
       "Looking for comparison category type outside of C++.")((void)0);

// Use an elaborated type for diagnostics which has a name containing the
// prepended 'std' namespace but not any inline namespace names.
auto TyForDiags = [&](ComparisonCategoryInfo *Info) {
  auto *NNS =
      NestedNameSpecifier::Create(Context, nullptr, getStdNamespace());
  return Context.getElaboratedType(ETK_None, NNS, Info->getType());
};

// Check if we've already successfully checked the comparison category type
// before. If so, skip checking it again.
ComparisonCategoryInfo *Info = Context.CompCategories.lookupInfo(Kind);
if (Info && FullyCheckedComparisonCategories[static_cast<unsigned>(Kind)]) {
  // The only thing we need to check is that the type has a reachable
  // definition in the current context.
  if (RequireCompleteType(Loc, TyForDiags(Info), diag::err_incomplete_type))
    return QualType();

  return Info->getType();
}

// If lookup failed
if (!Info) {
  std::string NameForDiags = "std::";
  NameForDiags += ComparisonCategories::getCategoryString(Kind);
  Diag(Loc, diag::err_implied_comparison_category_type_not_found)
      << NameForDiags << (int)Usage;
  return QualType();
}

assert(Info->Kind == Kind)((void)0);
assert(Info->Record)((void)0);

// Update the Record decl in case we encountered a forward declaration on our
// first pass. FIXME: This is a bit of a hack.
if (Info->Record->hasDefinition())
  Info->Record = Info->Record->getDefinition();

if (RequireCompleteType(Loc, TyForDiags(Info), diag::err_incomplete_type))
  return QualType();

InvalidSTLDiagnoser UnsupportedSTLError{*this, Loc, TyForDiags(Info)};

if (!Info->Record->isTriviallyCopyable())
  return UnsupportedSTLError(USS_NonTrivial);

for (const CXXBaseSpecifier &BaseSpec : Info->Record->bases()) {
  CXXRecordDecl *Base = BaseSpec.getType()->getAsCXXRecordDecl();
  // Tolerate empty base classes.
  if (Base->isEmpty())
    continue;
  // Reject STL implementations which have at least one non-empty base.
  return UnsupportedSTLError();
}

// Check that the STL has implemented the types using a single integer field.
// This expectation allows better codegen for builtin operators. We require:
//   (1) The class has exactly one field.
//   (2) The field is an integral or enumeration type.
auto FIt = Info->Record->field_begin(), FEnd = Info->Record->field_end();
if (std::distance(FIt, FEnd) != 1 ||
    !FIt->getType()->isIntegralOrEnumerationType()) {
  return UnsupportedSTLError();
}

// Build each of the require values and store them in Info.
for (ComparisonCategoryResult CCR :
     ComparisonCategories::getPossibleResultsForType(Kind)) {
  StringRef MemName = ComparisonCategories::getResultString(CCR);
  ComparisonCategoryInfo::ValueInfo *ValInfo = Info->lookupValueInfo(CCR);

  if (!ValInfo)
    return UnsupportedSTLError(USS_MissingMember, MemName);

  VarDecl *VD = ValInfo->VD;
  assert(VD && "should not be null!")((void)0);

  // Attempt to diagnose reasons why the STL definition of this type
  // might be foobar, including it failing to be a constant expression.
  // TODO Handle more ways the lookup or result can be invalid.
  if (!VD->isStaticDataMember() ||
      !VD->isUsableInConstantExpressions(Context))
    return UnsupportedSTLError(USS_InvalidMember, MemName, VD);

  // Attempt to evaluate the var decl as a constant expression and extract
  // the value of its first field as a ICE. If this fails, the STL
  // implementation is not supported.
  if (!ValInfo->hasValidIntValue())
    return UnsupportedSTLError();

  MarkVariableReferenced(Loc, VD);
}

// We've successfully built the required types and expressions. Update
// the cache and return the newly cached value.
FullyCheckedComparisonCategories[static_cast<unsigned>(Kind)] = true;
return Info->getType();
11242}

11244/// Retrieve the special "std" namespace, which may require us to
11245/// implicitly define the namespace.
11246NamespaceDecl *Sema::getOrCreateStdNamespace() {
if (!StdNamespace) {
  // The "std" namespace has not yet been defined, so build one implicitly.
  StdNamespace = NamespaceDecl::Create(Context,
                                       Context.getTranslationUnitDecl(),
                                       /*Inline=*/false,
                                       SourceLocation(), SourceLocation(),
                                       &PP.getIdentifierTable().get("std"),
                                       /*PrevDecl=*/nullptr);
  getStdNamespace()->setImplicit(true);
}

return getStdNamespace();
11259}

11261bool Sema::isStdInitializerList(QualType Ty, QualType *Element) {
assert(getLangOpts().CPlusPlus &&((void)0)
       "Looking for std::initializer_list outside of C++.")((void)0);

// We're looking for implicit instantiations of
// template <typename E> class std::initializer_list.

if (!StdNamespace) // If we haven't seen namespace std yet, this can't be it.
  return false;

ClassTemplateDecl *Template = nullptr;
const TemplateArgument *Arguments = nullptr;

if (const RecordType *RT = Ty->getAs<RecordType>()) {

  ClassTemplateSpecializationDecl *Specialization =
      dyn_cast<ClassTemplateSpecializationDecl>(RT->getDecl());
  if (!Specialization)
    return false;

  Template = Specialization->getSpecializedTemplate();
  Arguments = Specialization->getTemplateArgs().data();
} else if (const TemplateSpecializationType *TST =
               Ty->getAs<TemplateSpecializationType>()) {
  Template = dyn_cast_or_null<ClassTemplateDecl>(
      TST->getTemplateName().getAsTemplateDecl());
  Arguments = TST->getArgs();
}
if (!Template)
  return false;

if (!StdInitializerList) {
  // Haven't recognized std::initializer_list yet, maybe this is it.
  CXXRecordDecl *TemplateClass = Template->getTemplatedDecl();
  if (TemplateClass->getIdentifier() !=
          &PP.getIdentifierTable().get("initializer_list") ||
      !getStdNamespace()->InEnclosingNamespaceSetOf(
          TemplateClass->getDeclContext()))
    return false;
  // This is a template called std::initializer_list, but is it the right
  // template?
  TemplateParameterList *Params = Template->getTemplateParameters();
  if (Params->getMinRequiredArguments() != 1)
    return false;
  if (!isa<TemplateTypeParmDecl>(Params->getParam(0)))
    return false;

  // It's the right template.
  StdInitializerList = Template;
}

if (Template->getCanonicalDecl() != StdInitializerList->getCanonicalDecl())
  return false;

// This is an instance of std::initializer_list. Find the argument type.
if (Element)
  *Element = Arguments[0].getAsType();
return true;
11319}

11321static ClassTemplateDecl *LookupStdInitializerList(Sema &S, SourceLocation Loc){
NamespaceDecl *Std = S.getStdNamespace();
if (!Std) {
  S.Diag(Loc, diag::err_implied_std_initializer_list_not_found);
  return nullptr;
}

LookupResult Result(S, &S.PP.getIdentifierTable().get("initializer_list"),
                    Loc, Sema::LookupOrdinaryName);
if (!S.LookupQualifiedName(Result, Std)) {
  S.Diag(Loc, diag::err_implied_std_initializer_list_not_found);
  return nullptr;
}
ClassTemplateDecl *Template = Result.getAsSingle<ClassTemplateDecl>();
if (!Template) {
  Result.suppressDiagnostics();
  // We found something weird. Complain about the first thing we found.
  NamedDecl *Found = *Result.begin();
  S.Diag(Found->getLocation(), diag::err_malformed_std_initializer_list);
  return nullptr;
}

// We found some template called std::initializer_list. Now verify that it's
// correct.
TemplateParameterList *Params = Template->getTemplateParameters();
if (Params->getMinRequiredArguments() != 1 ||
    !isa<TemplateTypeParmDecl>(Params->getParam(0))) {
  S.Diag(Template->getLocation(), diag::err_malformed_std_initializer_list);
  return nullptr;
}

return Template;
11353}

11355QualType Sema::BuildStdInitializerList(QualType Element, SourceLocation Loc) {
if (!StdInitializerList) {
  StdInitializerList = LookupStdInitializerList(*this, Loc);
  if (!StdInitializerList)
    return QualType();
}

TemplateArgumentListInfo Args(Loc, Loc);
Args.addArgument(TemplateArgumentLoc(TemplateArgument(Element),
                                     Context.getTrivialTypeSourceInfo(Element,
                                                                      Loc)));
return Context.getCanonicalType(
    CheckTemplateIdType(TemplateName(StdInitializerList), Loc, Args));
11368}

11370bool Sema::isInitListConstructor(const FunctionDecl *Ctor) {
// C++ [dcl.init.list]p2:
//   A constructor is an initializer-list constructor if its first parameter
//   is of type std::initializer_list<E> or reference to possibly cv-qualified
//   std::initializer_list<E> for some type E, and either there are no other
//   parameters or else all other parameters have default arguments.
if (!Ctor->hasOneParamOrDefaultArgs())
  return false;

QualType ArgType = Ctor->getParamDecl(0)->getType();
if (const ReferenceType *RT = ArgType->getAs<ReferenceType>())
  ArgType = RT->getPointeeType().getUnqualifiedType();

return isStdInitializerList(ArgType, nullptr);
11384}

11386/// Determine whether a using statement is in a context where it will be
11387/// apply in all contexts.
11388static bool IsUsingDirectiveInToplevelContext(DeclContext *CurContext) {
switch (CurContext->getDeclKind()) {
  case Decl::TranslationUnit:
    return true;
  case Decl::LinkageSpec:
    return IsUsingDirectiveInToplevelContext(CurContext->getParent());
  default:
    return false;
}
11397}

11399namespace {

11401// Callback to only accept typo corrections that are namespaces.
11402class NamespaceValidatorCCC final : public CorrectionCandidateCallback {
11403public:
bool ValidateCandidate(const TypoCorrection &candidate) override {
  if (NamedDecl *ND = candidate.getCorrectionDecl())
    return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
  return false;
}

std::unique_ptr<CorrectionCandidateCallback> clone() override {
  return std::make_unique<NamespaceValidatorCCC>(*this);
}
11413};

11415}

11417static bool TryNamespaceTypoCorrection(Sema &S, LookupResult &R, Scope *Sc,
                                     CXXScopeSpec &SS,
                                     SourceLocation IdentLoc,
                                     IdentifierInfo *Ident) {
R.clear();
NamespaceValidatorCCC CCC{};
if (TypoCorrection Corrected =
        S.CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), Sc, &SS, CCC,
                      Sema::CTK_ErrorRecovery)) {
  if (DeclContext *DC = S.computeDeclContext(SS, false)) {
    std::string CorrectedStr(Corrected.getAsString(S.getLangOpts()));
    bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
                            Ident->getName().equals(CorrectedStr);
    S.diagnoseTypo(Corrected,
                   S.PDiag(diag::err_using_directive_member_suggest)
                     << Ident << DC << DroppedSpecifier << SS.getRange(),
                   S.PDiag(diag::note_namespace_defined_here));
  } else {
    S.diagnoseTypo(Corrected,
                   S.PDiag(diag::err_using_directive_suggest) << Ident,
                   S.PDiag(diag::note_namespace_defined_here));
  }
  R.addDecl(Corrected.getFoundDecl());
  return true;
}
return false;
11443}

11445Decl *Sema::ActOnUsingDirective(Scope *S, SourceLocation UsingLoc,
                              SourceLocation NamespcLoc, CXXScopeSpec &SS,
                              SourceLocation IdentLoc,
                              IdentifierInfo *NamespcName,
                              const ParsedAttributesView &AttrList) {
assert(!SS.isInvalid() && "Invalid CXXScopeSpec.")((void)0);
assert(NamespcName && "Invalid NamespcName.")((void)0);
assert(IdentLoc.isValid() && "Invalid NamespceName location.")((void)0);

// This can only happen along a recovery path.
while (S->isTemplateParamScope())
  S = S->getParent();
assert(S->getFlags() & Scope::DeclScope && "Invalid Scope.")((void)0);

UsingDirectiveDecl *UDir = nullptr;
NestedNameSpecifier *Qualifier = nullptr;
if (SS.isSet())
  Qualifier = SS.getScopeRep();

// Lookup namespace name.
LookupResult R(*this, NamespcName, IdentLoc, LookupNamespaceName);
LookupParsedName(R, S, &SS);
if (R.isAmbiguous())
  return nullptr;

if (R.empty()) {
  R.clear();
  // Allow "using namespace std;" or "using namespace ::std;" even if
  // "std" hasn't been defined yet, for GCC compatibility.
  if ((!Qualifier || Qualifier->getKind() == NestedNameSpecifier::Global) &&
      NamespcName->isStr("std")) {
    Diag(IdentLoc, diag::ext_using_undefined_std);
    R.addDecl(getOrCreateStdNamespace());
    R.resolveKind();
  }
  // Otherwise, attempt typo correction.
  else TryNamespaceTypoCorrection(*this, R, S, SS, IdentLoc, NamespcName);
}

if (!R.empty()) {
  NamedDecl *Named = R.getRepresentativeDecl();
  NamespaceDecl *NS = R.getAsSingle<NamespaceDecl>();
  assert(NS && "expected namespace decl")((void)0);

  // The use of a nested name specifier may trigger deprecation warnings.
  DiagnoseUseOfDecl(Named, IdentLoc);

  // C++ [namespace.udir]p1:
  //   A using-directive specifies that the names in the nominated
  //   namespace can be used in the scope in which the
  //   using-directive appears after the using-directive. During
  //   unqualified name lookup (3.4.1), the names appear as if they
  //   were declared in the nearest enclosing namespace which
  //   contains both the using-directive and the nominated
  //   namespace. [Note: in this context, "contains" means "contains
  //   directly or indirectly". ]

  // Find enclosing context containing both using-directive and
  // nominated namespace.
  DeclContext *CommonAncestor = NS;
  while (CommonAncestor && !CommonAncestor->Encloses(CurContext))
    CommonAncestor = CommonAncestor->getParent();

  UDir = UsingDirectiveDecl::Create(Context, CurContext, UsingLoc, NamespcLoc,
                                    SS.getWithLocInContext(Context),
                                    IdentLoc, Named, CommonAncestor);

  if (IsUsingDirectiveInToplevelContext(CurContext) &&
      !SourceMgr.isInMainFile(SourceMgr.getExpansionLoc(IdentLoc))) {
    Diag(IdentLoc, diag::warn_using_directive_in_header);
  }

  PushUsingDirective(S, UDir);
} else {
  Diag(IdentLoc, diag::err_expected_namespace_name) << SS.getRange();
}

if (UDir)
  ProcessDeclAttributeList(S, UDir, AttrList);

return UDir;
11526}

11528void Sema::PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir) {
// If the scope has an associated entity and the using directive is at
// namespace or translation unit scope, add the UsingDirectiveDecl into
// its lookup structure so qualified name lookup can find it.
DeclContext *Ctx = S->getEntity();
if (Ctx && !Ctx->isFunctionOrMethod())
  Ctx->addDecl(UDir);
else
  // Otherwise, it is at block scope. The using-directives will affect lookup
  // only to the end of the scope.
  S->PushUsingDirective(UDir);
11539}

11541Decl *Sema::ActOnUsingDeclaration(Scope *S, AccessSpecifier AS,
                                SourceLocation UsingLoc,
                                SourceLocation TypenameLoc, CXXScopeSpec &SS,
                                UnqualifiedId &Name,
                                SourceLocation EllipsisLoc,
                                const ParsedAttributesView &AttrList) {
assert(S->getFlags() & Scope::DeclScope && "Invalid Scope.")((void)0);

if (SS.isEmpty()) {
  Diag(Name.getBeginLoc(), diag::err_using_requires_qualname);
  return nullptr;
}

switch (Name.getKind()) {
case UnqualifiedIdKind::IK_ImplicitSelfParam:
case UnqualifiedIdKind::IK_Identifier:
case UnqualifiedIdKind::IK_OperatorFunctionId:
case UnqualifiedIdKind::IK_LiteralOperatorId:
case UnqualifiedIdKind::IK_ConversionFunctionId:
  break;

case UnqualifiedIdKind::IK_ConstructorName:
case UnqualifiedIdKind::IK_ConstructorTemplateId:
  // C++11 inheriting constructors.
  Diag(Name.getBeginLoc(),
       getLangOpts().CPlusPlus11
           ? diag::warn_cxx98_compat_using_decl_constructor
           : diag::err_using_decl_constructor)
      << SS.getRange();

  if (getLangOpts().CPlusPlus11) break;

  return nullptr;

case UnqualifiedIdKind::IK_DestructorName:
  Diag(Name.getBeginLoc(), diag::err_using_decl_destructor) << SS.getRange();
  return nullptr;

case UnqualifiedIdKind::IK_TemplateId:
  Diag(Name.getBeginLoc(), diag::err_using_decl_template_id)
      << SourceRange(Name.TemplateId->LAngleLoc, Name.TemplateId->RAngleLoc);
  return nullptr;

case UnqualifiedIdKind::IK_DeductionGuideName:
  llvm_unreachable("cannot parse qualified deduction guide name")__builtin_unreachable();
}

DeclarationNameInfo TargetNameInfo = GetNameFromUnqualifiedId(Name);
DeclarationName TargetName = TargetNameInfo.getName();
if (!TargetName)
  return nullptr;

// Warn about access declarations.
if (UsingLoc.isInvalid()) {
  Diag(Name.getBeginLoc(), getLangOpts().CPlusPlus11
                               ? diag::err_access_decl
                               : diag::warn_access_decl_deprecated)
      << FixItHint::CreateInsertion(SS.getRange().getBegin(), "using ");
}

if (EllipsisLoc.isInvalid()) {
  if (DiagnoseUnexpandedParameterPack(SS, UPPC_UsingDeclaration) ||
      DiagnoseUnexpandedParameterPack(TargetNameInfo, UPPC_UsingDeclaration))
    return nullptr;
} else {
  if (!SS.getScopeRep()->containsUnexpandedParameterPack() &&
      !TargetNameInfo.containsUnexpandedParameterPack()) {
    Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
      << SourceRange(SS.getBeginLoc(), TargetNameInfo.getEndLoc());
    EllipsisLoc = SourceLocation();
  }
}

NamedDecl *UD =
    BuildUsingDeclaration(S, AS, UsingLoc, TypenameLoc.isValid(), TypenameLoc,
                          SS, TargetNameInfo, EllipsisLoc, AttrList,
                          /*IsInstantiation*/ false,
                          AttrList.hasAttribute(ParsedAttr::AT_UsingIfExists));
if (UD)
  PushOnScopeChains(UD, S, /*AddToContext*/ false);

return UD;
11623}

11625Decl *Sema::ActOnUsingEnumDeclaration(Scope *S, AccessSpecifier AS,
                                    SourceLocation UsingLoc,
                                    SourceLocation EnumLoc,
                                    const DeclSpec &DS) {
switch (DS.getTypeSpecType()) {
case DeclSpec::TST_error:
  // This will already have been diagnosed
  return nullptr;

case DeclSpec::TST_enum:
  break;

case DeclSpec::TST_typename:
  Diag(DS.getTypeSpecTypeLoc(), diag::err_using_enum_is_dependent);
  return nullptr;

default:
  llvm_unreachable("unexpected DeclSpec type")__builtin_unreachable();
}

// As with enum-decls, we ignore attributes for now.
auto *Enum = cast<EnumDecl>(DS.getRepAsDecl());
if (auto *Def = Enum->getDefinition())
  Enum = Def;

auto *UD = BuildUsingEnumDeclaration(S, AS, UsingLoc, EnumLoc,
                                     DS.getTypeSpecTypeNameLoc(), Enum);
if (UD)
  PushOnScopeChains(UD, S, /*AddToContext*/ false);

return UD;
11656}

11658/// Determine whether a using declaration considers the given
11659/// declarations as "equivalent", e.g., if they are redeclarations of
11660/// the same entity or are both typedefs of the same type.
11661static bool
11662IsEquivalentForUsingDecl(ASTContext &Context, NamedDecl *D1, NamedDecl *D2) {
if (D1->getCanonicalDecl() == D2->getCanonicalDecl())
  return true;

if (TypedefNameDecl *TD1 = dyn_cast<TypedefNameDecl>(D1))
  if (TypedefNameDecl *TD2 = dyn_cast<TypedefNameDecl>(D2))
    return Context.hasSameType(TD1->getUnderlyingType(),
                               TD2->getUnderlyingType());

// Two using_if_exists using-declarations are equivalent if both are
// unresolved.
if (isa<UnresolvedUsingIfExistsDecl>(D1) &&
    isa<UnresolvedUsingIfExistsDecl>(D2))
  return true;

return false;
11678}


11681/// Determines whether to create a using shadow decl for a particular
11682/// decl, given the set of decls existing prior to this using lookup.
11683bool Sema::CheckUsingShadowDecl(BaseUsingDecl *BUD, NamedDecl *Orig,
                              const LookupResult &Previous,
                              UsingShadowDecl *&PrevShadow) {
// Diagnose finding a decl which is not from a base class of the
// current class.  We do this now because there are cases where this
// function will silently decide not to build a shadow decl, which
// will pre-empt further diagnostics.
//
// We don't need to do this in C++11 because we do the check once on
// the qualifier.
//
// FIXME: diagnose the following if we care enough:
//   struct A { int foo; };
//   struct B : A { using A::foo; };
//   template <class T> struct C : A {};
//   template <class T> struct D : C<T> { using B::foo; } // <---
// This is invalid (during instantiation) in C++03 because B::foo
// resolves to the using decl in B, which is not a base class of D<T>.
// We can't diagnose it immediately because C<T> is an unknown
// specialization. The UsingShadowDecl in D<T> then points directly
// to A::foo, which will look well-formed when we instantiate.
// The right solution is to not collapse the shadow-decl chain.
if (!getLangOpts().CPlusPlus11 && CurContext->isRecord())
  if (auto *Using = dyn_cast<UsingDecl>(BUD)) {
    DeclContext *OrigDC = Orig->getDeclContext();

    // Handle enums and anonymous structs.
    if (isa<EnumDecl>(OrigDC))
      OrigDC = OrigDC->getParent();
    CXXRecordDecl *OrigRec = cast<CXXRecordDecl>(OrigDC);
    while (OrigRec->isAnonymousStructOrUnion())
      OrigRec = cast<CXXRecordDecl>(OrigRec->getDeclContext());

    if (cast<CXXRecordDecl>(CurContext)->isProvablyNotDerivedFrom(OrigRec)) {
      if (OrigDC == CurContext) {
        Diag(Using->getLocation(),
             diag::err_using_decl_nested_name_specifier_is_current_class)
            << Using->getQualifierLoc().getSourceRange();
        Diag(Orig->getLocation(), diag::note_using_decl_target);
        Using->setInvalidDecl();
        return true;
      }

      Diag(Using->getQualifierLoc().getBeginLoc(),
           diag::err_using_decl_nested_name_specifier_is_not_base_class)
          << Using->getQualifier() << cast<CXXRecordDecl>(CurContext)
          << Using->getQualifierLoc().getSourceRange();
      Diag(Orig->getLocation(), diag::note_using_decl_target);
      Using->setInvalidDecl();
      return true;
    }
  }

if (Previous.empty()) return false;

NamedDecl *Target = Orig;
if (isa<UsingShadowDecl>(Target))
  Target = cast<UsingShadowDecl>(Target)->getTargetDecl();

// If the target happens to be one of the previous declarations, we
// don't have a conflict.
//
// FIXME: but we might be increasing its access, in which case we
// should redeclare it.
NamedDecl *NonTag = nullptr, *Tag = nullptr;
bool FoundEquivalentDecl = false;
for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
       I != E; ++I) {
  NamedDecl *D = (*I)->getUnderlyingDecl();
  // We can have UsingDecls in our Previous results because we use the same
  // LookupResult for checking whether the UsingDecl itself is a valid
  // redeclaration.
  if (isa<UsingDecl>(D) || isa<UsingPackDecl>(D) || isa<UsingEnumDecl>(D))
    continue;

  if (auto *RD = dyn_cast<CXXRecordDecl>(D)) {
    // C++ [class.mem]p19:
    //   If T is the name of a class, then [every named member other than
    //   a non-static data member] shall have a name different from T
    if (RD->isInjectedClassName() && !isa<FieldDecl>(Target) &&
        !isa<IndirectFieldDecl>(Target) &&
        !isa<UnresolvedUsingValueDecl>(Target) &&
        DiagnoseClassNameShadow(
            CurContext,
            DeclarationNameInfo(BUD->getDeclName(), BUD->getLocation())))
      return true;
  }

  if (IsEquivalentForUsingDecl(Context, D, Target)) {
    if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(*I))
      PrevShadow = Shadow;
    FoundEquivalentDecl = true;
  } else if (isEquivalentInternalLinkageDeclaration(D, Target)) {
    // We don't conflict with an existing using shadow decl of an equivalent
    // declaration, but we're not a redeclaration of it.
    FoundEquivalentDecl = true;
  }

  if (isVisible(D))
    (isa<TagDecl>(D) ? Tag : NonTag) = D;
}

if (FoundEquivalentDecl)
  return false;

// Always emit a diagnostic for a mismatch between an unresolved
// using_if_exists and a resolved using declaration in either direction.
if (isa<UnresolvedUsingIfExistsDecl>(Target) !=
    (isa_and_nonnull<UnresolvedUsingIfExistsDecl>(NonTag))) {
  if (!NonTag && !Tag)
    return false;
  Diag(BUD->getLocation(), diag::err_using_decl_conflict);
  Diag(Target->getLocation(), diag::note_using_decl_target);
  Diag((NonTag ? NonTag : Tag)->getLocation(),
       diag::note_using_decl_conflict);
  BUD->setInvalidDecl();
  return true;
}

if (FunctionDecl *FD = Target->getAsFunction()) {
  NamedDecl *OldDecl = nullptr;
  switch (CheckOverload(nullptr, FD, Previous, OldDecl,
                        /*IsForUsingDecl*/ true)) {
  case Ovl_Overload:
    return false;

  case Ovl_NonFunction:
    Diag(BUD->getLocation(), diag::err_using_decl_conflict);
    break;

  // We found a decl with the exact signature.
  case Ovl_Match:
    // If we're in a record, we want to hide the target, so we
    // return true (without a diagnostic) to tell the caller not to
    // build a shadow decl.
    if (CurContext->isRecord())
      return true;

    // If we're not in a record, this is an error.
    Diag(BUD->getLocation(), diag::err_using_decl_conflict);
    break;
  }

  Diag(Target->getLocation(), diag::note_using_decl_target);
  Diag(OldDecl->getLocation(), diag::note_using_decl_conflict);
  BUD->setInvalidDecl();
  return true;
}

// Target is not a function.

if (isa<TagDecl>(Target)) {
  // No conflict between a tag and a non-tag.
  if (!Tag) return false;

  Diag(BUD->getLocation(), diag::err_using_decl_conflict);
  Diag(Target->getLocation(), diag::note_using_decl_target);
  Diag(Tag->getLocation(), diag::note_using_decl_conflict);
  BUD->setInvalidDecl();
  return true;
}

// No conflict between a tag and a non-tag.
if (!NonTag) return false;

Diag(BUD->getLocation(), diag::err_using_decl_conflict);
Diag(Target->getLocation(), diag::note_using_decl_target);
Diag(NonTag->getLocation(), diag::note_using_decl_conflict);
BUD->setInvalidDecl();
return true;
11853}

11855/// Determine whether a direct base class is a virtual base class.
11856static bool isVirtualDirectBase(CXXRecordDecl *Derived, CXXRecordDecl *Base) {
if (!Derived->getNumVBases())
  return false;
for (auto &B : Derived->bases())
  if (B.getType()->getAsCXXRecordDecl() == Base)
    return B.isVirtual();
llvm_unreachable("not a direct base class")__builtin_unreachable();
11863}

11865/// Builds a shadow declaration corresponding to a 'using' declaration.
11866UsingShadowDecl *Sema::BuildUsingShadowDecl(Scope *S, BaseUsingDecl *BUD,
                                          NamedDecl *Orig,
                                          UsingShadowDecl *PrevDecl) {
// If we resolved to another shadow declaration, just coalesce them.
NamedDecl *Target = Orig;
if (isa<UsingShadowDecl>(Target)) {
  Target = cast<UsingShadowDecl>(Target)->getTargetDecl();
  assert(!isa<UsingShadowDecl>(Target) && "nested shadow declaration")((void)0);
}

NamedDecl *NonTemplateTarget = Target;
if (auto *TargetTD = dyn_cast<TemplateDecl>(Target))
  NonTemplateTarget = TargetTD->getTemplatedDecl();

UsingShadowDecl *Shadow;
if (NonTemplateTarget && isa<CXXConstructorDecl>(NonTemplateTarget)) {
  UsingDecl *Using = cast<UsingDecl>(BUD);
  bool IsVirtualBase =
      isVirtualDirectBase(cast<CXXRecordDecl>(CurContext),
                          Using->getQualifier()->getAsRecordDecl());
  Shadow = ConstructorUsingShadowDecl::Create(
      Context, CurContext, Using->getLocation(), Using, Orig, IsVirtualBase);
} else {
  Shadow = UsingShadowDecl::Create(Context, CurContext, BUD->getLocation(),
                                   Target->getDeclName(), BUD, Target);
}
BUD->addShadowDecl(Shadow);

Shadow->setAccess(BUD->getAccess());
if (Orig->isInvalidDecl() || BUD->isInvalidDecl())
  Shadow->setInvalidDecl();

Shadow->setPreviousDecl(PrevDecl);

if (S)
  PushOnScopeChains(Shadow, S);
else
  CurContext->addDecl(Shadow);


return Shadow;
11907}

11909/// Hides a using shadow declaration.  This is required by the current
11910/// using-decl implementation when a resolvable using declaration in a
11911/// class is followed by a declaration which would hide or override
11912/// one or more of the using decl's targets; for example:
11913///
11914///   struct Base { void foo(int); };
11915///   struct Derived : Base {
11916///     using Base::foo;
11917///     void foo(int);
11918///   };
11919///
11920/// The governing language is C++03 [namespace.udecl]p12:
11921///
11922///   When a using-declaration brings names from a base class into a
11923///   derived class scope, member functions in the derived class
11924///   override and/or hide member functions with the same name and
11925///   parameter types in a base class (rather than conflicting).
11926///
11927/// There are two ways to implement this:
11928///   (1) optimistically create shadow decls when they're not hidden
11929///       by existing declarations, or
11930///   (2) don't create any shadow decls (or at least don't make them
11931///       visible) until we've fully parsed/instantiated the class.
11932/// The problem with (1) is that we might have to retroactively remove
11933/// a shadow decl, which requires several O(n) operations because the
11934/// decl structures are (very reasonably) not designed for removal.
11935/// (2) avoids this but is very fiddly and phase-dependent.
11936void Sema::HideUsingShadowDecl(Scope *S, UsingShadowDecl *Shadow) {
if (Shadow->getDeclName().getNameKind() ==
      DeclarationName::CXXConversionFunctionName)
  cast<CXXRecordDecl>(Shadow->getDeclContext())->removeConversion(Shadow);

// Remove it from the DeclContext...
Shadow->getDeclContext()->removeDecl(Shadow);

// ...and the scope, if applicable...
if (S) {
  S->RemoveDecl(Shadow);
  IdResolver.RemoveDecl(Shadow);
}

// ...and the using decl.
Shadow->getIntroducer()->removeShadowDecl(Shadow);

// TODO: complain somehow if Shadow was used.  It shouldn't
// be possible for this to happen, because...?
11955}

11957/// Find the base specifier for a base class with the given type.
11958static CXXBaseSpecifier *findDirectBaseWithType(CXXRecordDecl *Derived,
                                              QualType DesiredBase,
                                              bool &AnyDependentBases) {
// Check whether the named type is a direct base class.
CanQualType CanonicalDesiredBase = DesiredBase->getCanonicalTypeUnqualified()
  .getUnqualifiedType();
for (auto &Base : Derived->bases()) {
  CanQualType BaseType = Base.getType()->getCanonicalTypeUnqualified();
  if (CanonicalDesiredBase == BaseType)
    return &Base;
  if (BaseType->isDependentType())
    AnyDependentBases = true;
}
return nullptr;
11972}

11974namespace {
11975class UsingValidatorCCC final : public CorrectionCandidateCallback {
11976public:
UsingValidatorCCC(bool HasTypenameKeyword, bool IsInstantiation,
                  NestedNameSpecifier *NNS, CXXRecordDecl *RequireMemberOf)
    : HasTypenameKeyword(HasTypenameKeyword),
      IsInstantiation(IsInstantiation), OldNNS(NNS),
      RequireMemberOf(RequireMemberOf) {}

bool ValidateCandidate(const TypoCorrection &Candidate) override {
  NamedDecl *ND = Candidate.getCorrectionDecl();

  // Keywords are not valid here.
  if (!ND || isa<NamespaceDecl>(ND))
    return false;

  // Completely unqualified names are invalid for a 'using' declaration.
  if (Candidate.WillReplaceSpecifier() && !Candidate.getCorrectionSpecifier())
    return false;

  // FIXME: Don't correct to a name that CheckUsingDeclRedeclaration would
  // reject.

  if (RequireMemberOf) {
    auto *FoundRecord = dyn_cast<CXXRecordDecl>(ND);
    if (FoundRecord && FoundRecord->isInjectedClassName()) {
      // No-one ever wants a using-declaration to name an injected-class-name
      // of a base class, unless they're declaring an inheriting constructor.
      ASTContext &Ctx = ND->getASTContext();
      if (!Ctx.getLangOpts().CPlusPlus11)
        return false;
      QualType FoundType = Ctx.getRecordType(FoundRecord);

      // Check that the injected-class-name is named as a member of its own
      // type; we don't want to suggest 'using Derived::Base;', since that
      // means something else.
      NestedNameSpecifier *Specifier =
          Candidate.WillReplaceSpecifier()
              ? Candidate.getCorrectionSpecifier()
              : OldNNS;
      if (!Specifier->getAsType() ||
          !Ctx.hasSameType(QualType(Specifier->getAsType(), 0), FoundType))
        return false;

      // Check that this inheriting constructor declaration actually names a
      // direct base class of the current class.
      bool AnyDependentBases = false;
      if (!findDirectBaseWithType(RequireMemberOf,
                                  Ctx.getRecordType(FoundRecord),
                                  AnyDependentBases) &&
          !AnyDependentBases)
        return false;
    } else {
      auto *RD = dyn_cast<CXXRecordDecl>(ND->getDeclContext());
      if (!RD || RequireMemberOf->isProvablyNotDerivedFrom(RD))
        return false;

      // FIXME: Check that the base class member is accessible?
    }
  } else {
    auto *FoundRecord = dyn_cast<CXXRecordDecl>(ND);
    if (FoundRecord && FoundRecord->isInjectedClassName())
      return false;
  }

  if (isa<TypeDecl>(ND))
    return HasTypenameKeyword || !IsInstantiation;

  return !HasTypenameKeyword;
}

std::unique_ptr<CorrectionCandidateCallback> clone() override {
  return std::make_unique<UsingValidatorCCC>(*this);
}

12049private:
bool HasTypenameKeyword;
bool IsInstantiation;
NestedNameSpecifier *OldNNS;
CXXRecordDecl *RequireMemberOf;
12054};
12055} // end anonymous namespace

12057/// Remove decls we can't actually see from a lookup being used to declare
12058/// shadow using decls.
12059///
12060/// \param S - The scope of the potential shadow decl
12061/// \param Previous - The lookup of a potential shadow decl's name.
12062void Sema::FilterUsingLookup(Scope *S, LookupResult &Previous) {
// It is really dumb that we have to do this.
LookupResult::Filter F = Previous.makeFilter();
while (F.hasNext()) {
  NamedDecl *D = F.next();
  if (!isDeclInScope(D, CurContext, S))
    F.erase();
  // If we found a local extern declaration that's not ordinarily visible,
  // and this declaration is being added to a non-block scope, ignore it.
  // We're only checking for scope conflicts here, not also for violations
  // of the linkage rules.
  else if (!CurContext->isFunctionOrMethod() && D->isLocalExternDecl() &&
           !(D->getIdentifierNamespace() & Decl::IDNS_Ordinary))
    F.erase();
}
F.done();
12078}

12080/// Builds a using declaration.
12081///
12082/// \param IsInstantiation - Whether this call arises from an
12083///   instantiation of an unresolved using declaration.  We treat
12084///   the lookup differently for these declarations.
12085NamedDecl *Sema::BuildUsingDeclaration(
  Scope *S, AccessSpecifier AS, SourceLocation UsingLoc,
  bool HasTypenameKeyword, SourceLocation TypenameLoc, CXXScopeSpec &SS,
  DeclarationNameInfo NameInfo, SourceLocation EllipsisLoc,
  const ParsedAttributesView &AttrList, bool IsInstantiation,
  bool IsUsingIfExists) {
assert(!SS.isInvalid() && "Invalid CXXScopeSpec.")((void)0);
SourceLocation IdentLoc = NameInfo.getLoc();
assert(IdentLoc.isValid() && "Invalid TargetName location.")((void)0);

// FIXME: We ignore attributes for now.

// For an inheriting constructor declaration, the name of the using
// declaration is the name of a constructor in this class, not in the
// base class.
DeclarationNameInfo UsingName = NameInfo;
if (UsingName.getName().getNameKind() == DeclarationName::CXXConstructorName)
  if (auto *RD = dyn_cast<CXXRecordDecl>(CurContext))
    UsingName.setName(Context.DeclarationNames.getCXXConstructorName(
        Context.getCanonicalType(Context.getRecordType(RD))));

// Do the redeclaration lookup in the current scope.
LookupResult Previous(*this, UsingName, LookupUsingDeclName,
                      ForVisibleRedeclaration);
Previous.setHideTags(false);
if (S) {
  LookupName(Previous, S);

  FilterUsingLookup(S, Previous);
} else {
  assert(IsInstantiation && "no scope in non-instantiation")((void)0);
  if (CurContext->isRecord())
    LookupQualifiedName(Previous, CurContext);
  else {
    // No redeclaration check is needed here; in non-member contexts we
    // diagnosed all possible conflicts with other using-declarations when
    // building the template:
    //
    // For a dependent non-type using declaration, the only valid case is
    // if we instantiate to a single enumerator. We check for conflicts
    // between shadow declarations we introduce, and we check in the template
    // definition for conflicts between a non-type using declaration and any
    // other declaration, which together covers all cases.
    //
    // A dependent typename using declaration will never successfully
    // instantiate, since it will always name a class member, so we reject
    // that in the template definition.
  }
}

// Check for invalid redeclarations.
if (CheckUsingDeclRedeclaration(UsingLoc, HasTypenameKeyword,
                                SS, IdentLoc, Previous))
  return nullptr;

// 'using_if_exists' doesn't make sense on an inherited constructor.
if (IsUsingIfExists && UsingName.getName().getNameKind() ==
                           DeclarationName::CXXConstructorName) {
  Diag(UsingLoc, diag::err_using_if_exists_on_ctor);
  return nullptr;
}

DeclContext *LookupContext = computeDeclContext(SS);
NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
if (!LookupContext || EllipsisLoc.isValid()) {
  NamedDecl *D;
  // Dependent scope, or an unexpanded pack
  if (!LookupContext && CheckUsingDeclQualifier(UsingLoc, HasTypenameKeyword,
                                                SS, NameInfo, IdentLoc))
    return nullptr;

  if (HasTypenameKeyword) {
    // FIXME: not all declaration name kinds are legal here
    D = UnresolvedUsingTypenameDecl::Create(Context, CurContext,
                                            UsingLoc, TypenameLoc,
                                            QualifierLoc,
                                            IdentLoc, NameInfo.getName(),
                                            EllipsisLoc);
  } else {
    D = UnresolvedUsingValueDecl::Create(Context, CurContext, UsingLoc,
                                         QualifierLoc, NameInfo, EllipsisLoc);
  }
  D->setAccess(AS);
  CurContext->addDecl(D);
  ProcessDeclAttributeList(S, D, AttrList);
  return D;
}

auto Build = [&](bool Invalid) {
  UsingDecl *UD =
      UsingDecl::Create(Context, CurContext, UsingLoc, QualifierLoc,
                        UsingName, HasTypenameKeyword);
  UD->setAccess(AS);
  CurContext->addDecl(UD);
  ProcessDeclAttributeList(S, UD, AttrList);
  UD->setInvalidDecl(Invalid);
  return UD;
};
auto BuildInvalid = [&]{ return Build(true); };
auto BuildValid = [&]{ return Build(false); };

if (RequireCompleteDeclContext(SS, LookupContext))
  return BuildInvalid();

// Look up the target name.
LookupResult R(*this, NameInfo, LookupOrdinaryName);

// Unlike most lookups, we don't always want to hide tag
// declarations: tag names are visible through the using declaration
// even if hidden by ordinary names, *except* in a dependent context
// where it's important for the sanity of two-phase lookup.
if (!IsInstantiation)
  R.setHideTags(false);

// For the purposes of this lookup, we have a base object type
// equal to that of the current context.
if (CurContext->isRecord()) {
  R.setBaseObjectType(
                 Context.getTypeDeclType(cast<CXXRecordDecl>(CurContext)));
}

LookupQualifiedName(R, LookupContext);

// Validate the context, now we have a lookup
if (CheckUsingDeclQualifier(UsingLoc, HasTypenameKeyword, SS, NameInfo,
                            IdentLoc, &R))
  return nullptr;

if (R.empty() && IsUsingIfExists)
  R.addDecl(UnresolvedUsingIfExistsDecl::Create(Context, CurContext, UsingLoc,
                                                UsingName.getName()),
            AS_public);

// Try to correct typos if possible. If constructor name lookup finds no
// results, that means the named class has no explicit constructors, and we
// suppressed declaring implicit ones (probably because it's dependent or
// invalid).
if (R.empty() &&
    NameInfo.getName().getNameKind() != DeclarationName::CXXConstructorName) {
  // HACK 2017-01-08: Work around an issue with libstdc++'s detection of
  // ::gets. Sometimes it believes that glibc provides a ::gets in cases where
  // it does not. The issue was fixed in libstdc++ 6.3 (2016-12-21) and later.
  auto *II = NameInfo.getName().getAsIdentifierInfo();
  if (getLangOpts().CPlusPlus14 && II && II->isStr("gets") &&
      CurContext->isStdNamespace() &&
      isa<TranslationUnitDecl>(LookupContext) &&
      getSourceManager().isInSystemHeader(UsingLoc))
    return nullptr;
  UsingValidatorCCC CCC(HasTypenameKeyword, IsInstantiation, SS.getScopeRep(),
                        dyn_cast<CXXRecordDecl>(CurContext));
  if (TypoCorrection Corrected =
          CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, &SS, CCC,
                      CTK_ErrorRecovery)) {
    // We reject candidates where DroppedSpecifier == true, hence the
    // literal '0' below.
    diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
                              << NameInfo.getName() << LookupContext << 0
                              << SS.getRange());

    // If we picked a correction with no attached Decl we can't do anything
    // useful with it, bail out.
    NamedDecl *ND = Corrected.getCorrectionDecl();
    if (!ND)
      return BuildInvalid();

    // If we corrected to an inheriting constructor, handle it as one.
    auto *RD = dyn_cast<CXXRecordDecl>(ND);
    if (RD && RD->isInjectedClassName()) {
      // The parent of the injected class name is the class itself.
      RD = cast<CXXRecordDecl>(RD->getParent());

      // Fix up the information we'll use to build the using declaration.
      if (Corrected.WillReplaceSpecifier()) {
        NestedNameSpecifierLocBuilder Builder;
        Builder.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
                            QualifierLoc.getSourceRange());
        QualifierLoc = Builder.getWithLocInContext(Context);
      }

      // In this case, the name we introduce is the name of a derived class
      // constructor.
      auto *CurClass = cast<CXXRecordDecl>(CurContext);
      UsingName.setName(Context.DeclarationNames.getCXXConstructorName(
          Context.getCanonicalType(Context.getRecordType(CurClass))));
      UsingName.setNamedTypeInfo(nullptr);
      for (auto *Ctor : LookupConstructors(RD))
        R.addDecl(Ctor);
      R.resolveKind();
    } else {
      // FIXME: Pick up all the declarations if we found an overloaded
      // function.
      UsingName.setName(ND->getDeclName());
      R.addDecl(ND);
    }
  } else {
    Diag(IdentLoc, diag::err_no_member)
      << NameInfo.getName() << LookupContext << SS.getRange();
    return BuildInvalid();
  }
}

if (R.isAmbiguous())
  return BuildInvalid();

if (HasTypenameKeyword) {
  // If we asked for a typename and got a non-type decl, error out.
  if (!R.getAsSingle<TypeDecl>() &&
      !R.getAsSingle<UnresolvedUsingIfExistsDecl>()) {
    Diag(IdentLoc, diag::err_using_typename_non_type);
    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
      Diag((*I)->getUnderlyingDecl()->getLocation(),
           diag::note_using_decl_target);
    return BuildInvalid();
  }
} else {
  // If we asked for a non-typename and we got a type, error out,
  // but only if this is an instantiation of an unresolved using
  // decl.  Otherwise just silently find the type name.
  if (IsInstantiation && R.getAsSingle<TypeDecl>()) {
    Diag(IdentLoc, diag::err_using_dependent_value_is_type);
    Diag(R.getFoundDecl()->getLocation(), diag::note_using_decl_target);
    return BuildInvalid();
  }
}

// C++14 [namespace.udecl]p6:
// A using-declaration shall not name a namespace.
if (R.getAsSingle<NamespaceDecl>()) {
  Diag(IdentLoc, diag::err_using_decl_can_not_refer_to_namespace)
    << SS.getRange();
  return BuildInvalid();
}

UsingDecl *UD = BuildValid();

// Some additional rules apply to inheriting constructors.
if (UsingName.getName().getNameKind() ==
      DeclarationName::CXXConstructorName) {
  // Suppress access diagnostics; the access check is instead performed at the
  // point of use for an inheriting constructor.
  R.suppressDiagnostics();
  if (CheckInheritingConstructorUsingDecl(UD))
    return UD;
}

for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
  UsingShadowDecl *PrevDecl = nullptr;
  if (!CheckUsingShadowDecl(UD, *I, Previous, PrevDecl))
    BuildUsingShadowDecl(S, UD, *I, PrevDecl);
}

return UD;
12337}

12339NamedDecl *Sema::BuildUsingEnumDeclaration(Scope *S, AccessSpecifier AS,
                                         SourceLocation UsingLoc,
                                         SourceLocation EnumLoc,
                                         SourceLocation NameLoc,
                                         EnumDecl *ED) {
bool Invalid = false;

if (CurContext->getRedeclContext()->isRecord()) {
  /// In class scope, check if this is a duplicate, for better a diagnostic.
  DeclarationNameInfo UsingEnumName(ED->getDeclName(), NameLoc);
  LookupResult Previous(*this, UsingEnumName, LookupUsingDeclName,
                        ForVisibleRedeclaration);

  LookupName(Previous, S);

  for (NamedDecl *D : Previous)
    if (UsingEnumDecl *UED = dyn_cast<UsingEnumDecl>(D))
      if (UED->getEnumDecl() == ED) {
        Diag(UsingLoc, diag::err_using_enum_decl_redeclaration)
            << SourceRange(EnumLoc, NameLoc);
        Diag(D->getLocation(), diag::note_using_enum_decl) << 1;
        Invalid = true;
        break;
      }
}

if (RequireCompleteEnumDecl(ED, NameLoc))
  Invalid = true;

UsingEnumDecl *UD = UsingEnumDecl::Create(Context, CurContext, UsingLoc,
                                          EnumLoc, NameLoc, ED);
UD->setAccess(AS);
CurContext->addDecl(UD);

if (Invalid) {
  UD->setInvalidDecl();
  return UD;
}

// Create the shadow decls for each enumerator
for (EnumConstantDecl *EC : ED->enumerators()) {
  UsingShadowDecl *PrevDecl = nullptr;
  DeclarationNameInfo DNI(EC->getDeclName(), EC->getLocation());
  LookupResult Previous(*this, DNI, LookupOrdinaryName,
                        ForVisibleRedeclaration);
  LookupName(Previous, S);
  FilterUsingLookup(S, Previous);

  if (!CheckUsingShadowDecl(UD, EC, Previous, PrevDecl))
    BuildUsingShadowDecl(S, UD, EC, PrevDecl);
}

return UD;
12392}

12394NamedDecl *Sema::BuildUsingPackDecl(NamedDecl *InstantiatedFrom,
                                  ArrayRef<NamedDecl *> Expansions) {
assert(isa<UnresolvedUsingValueDecl>(InstantiatedFrom) ||((void)0)
       isa<UnresolvedUsingTypenameDecl>(InstantiatedFrom) ||((void)0)
       isa<UsingPackDecl>(InstantiatedFrom))((void)0);

auto *UPD =
    UsingPackDecl::Create(Context, CurContext, InstantiatedFrom, Expansions);
UPD->setAccess(InstantiatedFrom->getAccess());
CurContext->addDecl(UPD);
return UPD;
12405}

12407/// Additional checks for a using declaration referring to a constructor name.
12408bool Sema::CheckInheritingConstructorUsingDecl(UsingDecl *UD) {
assert(!UD->hasTypename() && "expecting a constructor name")((void)0);

const Type *SourceType = UD->getQualifier()->getAsType();
assert(SourceType &&((void)0)
       "Using decl naming constructor doesn't have type in scope spec.")((void)0);
CXXRecordDecl *TargetClass = cast<CXXRecordDecl>(CurContext);

// Check whether the named type is a direct base class.
bool AnyDependentBases = false;
auto *Base = findDirectBaseWithType(TargetClass, QualType(SourceType, 0),
                                    AnyDependentBases);
if (!Base && !AnyDependentBases) {
  Diag(UD->getUsingLoc(),
       diag::err_using_decl_constructor_not_in_direct_base)
    << UD->getNameInfo().getSourceRange()
    << QualType(SourceType, 0) << TargetClass;
  UD->setInvalidDecl();
  return true;
}

if (Base)
  Base->setInheritConstructors();

return false;
12433}

12435/// Checks that the given using declaration is not an invalid
12436/// redeclaration.  Note that this is checking only for the using decl
12437/// itself, not for any ill-formedness among the UsingShadowDecls.
12438bool Sema::CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
                                     bool HasTypenameKeyword,
                                     const CXXScopeSpec &SS,
                                     SourceLocation NameLoc,
                                     const LookupResult &Prev) {
NestedNameSpecifier *Qual = SS.getScopeRep();

// C++03 [namespace.udecl]p8:
// C++0x [namespace.udecl]p10:
//   A using-declaration is a declaration and can therefore be used
//   repeatedly where (and only where) multiple declarations are
//   allowed.
//
// That's in non-member contexts.
if (!CurContext->getRedeclContext()->isRecord()) {
  // A dependent qualifier outside a class can only ever resolve to an
  // enumeration type. Therefore it conflicts with any other non-type
  // declaration in the same scope.
  // FIXME: How should we check for dependent type-type conflicts at block
  // scope?
  if (Qual->isDependent() && !HasTypenameKeyword) {
    for (auto *D : Prev) {
      if (!isa<TypeDecl>(D) && !isa<UsingDecl>(D) && !isa<UsingPackDecl>(D)) {
        bool OldCouldBeEnumerator =
            isa<UnresolvedUsingValueDecl>(D) || isa<EnumConstantDecl>(D);
        Diag(NameLoc,
             OldCouldBeEnumerator ? diag::err_redefinition
                                  : diag::err_redefinition_different_kind)
            << Prev.getLookupName();
        Diag(D->getLocation(), diag::note_previous_definition);
        return true;
      }
    }
  }
  return false;
}

const NestedNameSpecifier *CNNS =
    Context.getCanonicalNestedNameSpecifier(Qual);
for (LookupResult::iterator I = Prev.begin(), E = Prev.end(); I != E; ++I) {
  NamedDecl *D = *I;

  bool DTypename;
  NestedNameSpecifier *DQual;
  if (UsingDecl *UD = dyn_cast<UsingDecl>(D)) {
    DTypename = UD->hasTypename();
    DQual = UD->getQualifier();
  } else if (UnresolvedUsingValueDecl *UD
               = dyn_cast<UnresolvedUsingValueDecl>(D)) {
    DTypename = false;
    DQual = UD->getQualifier();
  } else if (UnresolvedUsingTypenameDecl *UD
               = dyn_cast<UnresolvedUsingTypenameDecl>(D)) {
    DTypename = true;
    DQual = UD->getQualifier();
  } else continue;

  // using decls differ if one says 'typename' and the other doesn't.
  // FIXME: non-dependent using decls?
  if (HasTypenameKeyword != DTypename) continue;

  // using decls differ if they name different scopes (but note that
  // template instantiation can cause this check to trigger when it
  // didn't before instantiation).
  if (CNNS != Context.getCanonicalNestedNameSpecifier(DQual))
    continue;

  Diag(NameLoc, diag::err_using_decl_redeclaration) << SS.getRange();
  Diag(D->getLocation(), diag::note_using_decl) << 1;
  return true;
}

return false;
12511}

12513/// Checks that the given nested-name qualifier used in a using decl
12514/// in the current context is appropriately related to the current
12515/// scope.  If an error is found, diagnoses it and returns true.
12516/// R is nullptr, if the caller has not (yet) done a lookup, otherwise it's the
12517/// result of that lookup. UD is likewise nullptr, except when we have an
12518/// already-populated UsingDecl whose shadow decls contain the same information
12519/// (i.e. we're instantiating a UsingDecl with non-dependent scope).
12520bool Sema::CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
                                 const CXXScopeSpec &SS,
                                 const DeclarationNameInfo &NameInfo,
                                 SourceLocation NameLoc,
                                 const LookupResult *R, const UsingDecl *UD) {
DeclContext *NamedContext = computeDeclContext(SS);
assert(bool(NamedContext) == (R || UD) && !(R && UD) &&((void)0)
       "resolvable context must have exactly one set of decls")((void)0);

// C++ 20 permits using an enumerator that does not have a class-hierarchy
// relationship.
bool Cxx20Enumerator = false;
if (NamedContext) {
  EnumConstantDecl *EC = nullptr;
  if (R)
    EC = R->getAsSingle<EnumConstantDecl>();
  else if (UD && UD->shadow_size() == 1)
    EC = dyn_cast<EnumConstantDecl>(UD->shadow_begin()->getTargetDecl());
  if (EC)
    Cxx20Enumerator = getLangOpts().CPlusPlus20;

  if (auto *ED = dyn_cast<EnumDecl>(NamedContext)) {
    // C++14 [namespace.udecl]p7:
    // A using-declaration shall not name a scoped enumerator.
    // C++20 p1099 permits enumerators.
    if (EC && R && ED->isScoped())
      Diag(SS.getBeginLoc(),
           getLangOpts().CPlusPlus20
               ? diag::warn_cxx17_compat_using_decl_scoped_enumerator
               : diag::ext_using_decl_scoped_enumerator)
          << SS.getRange();

    // We want to consider the scope of the enumerator
    NamedContext = ED->getDeclContext();
  }
}

if (!CurContext->isRecord()) {
  // C++03 [namespace.udecl]p3:
  // C++0x [namespace.udecl]p8:
  //   A using-declaration for a class member shall be a member-declaration.
  // C++20 [namespace.udecl]p7
  //   ... other than an enumerator ...

  // If we weren't able to compute a valid scope, it might validly be a
  // dependent class or enumeration scope. If we have a 'typename' keyword,
  // the scope must resolve to a class type.
  if (NamedContext ? !NamedContext->getRedeclContext()->isRecord()
                   : !HasTypename)
    return false; // OK

  Diag(NameLoc,
       Cxx20Enumerator
           ? diag::warn_cxx17_compat_using_decl_class_member_enumerator
           : diag::err_using_decl_can_not_refer_to_class_member)
      << SS.getRange();

  if (Cxx20Enumerator)
    return false; // OK

  auto *RD = NamedContext
                 ? cast<CXXRecordDecl>(NamedContext->getRedeclContext())
                 : nullptr;
  if (RD && !RequireCompleteDeclContext(const_cast<CXXScopeSpec &>(SS), RD)) {
    // See if there's a helpful fixit

    if (!R) {
      // We will have already diagnosed the problem on the template
      // definition,  Maybe we should do so again?
    } else if (R->getAsSingle<TypeDecl>()) {
      if (getLangOpts().CPlusPlus11) {
        // Convert 'using X::Y;' to 'using Y = X::Y;'.
        Diag(SS.getBeginLoc(), diag::note_using_decl_class_member_workaround)
          << 0 // alias declaration
          << FixItHint::CreateInsertion(SS.getBeginLoc(),
                                        NameInfo.getName().getAsString() +
                                            " = ");
      } else {
        // Convert 'using X::Y;' to 'typedef X::Y Y;'.
        SourceLocation InsertLoc = getLocForEndOfToken(NameInfo.getEndLoc());
        Diag(InsertLoc, diag::note_using_decl_class_member_workaround)
          << 1 // typedef declaration
          << FixItHint::CreateReplacement(UsingLoc, "typedef")
          << FixItHint::CreateInsertion(
                 InsertLoc, " " + NameInfo.getName().getAsString());
      }
    } else if (R->getAsSingle<VarDecl>()) {
      // Don't provide a fixit outside C++11 mode; we don't want to suggest
      // repeating the type of the static data member here.
      FixItHint FixIt;
      if (getLangOpts().CPlusPlus11) {
        // Convert 'using X::Y;' to 'auto &Y = X::Y;'.
        FixIt = FixItHint::CreateReplacement(
            UsingLoc, "auto &" + NameInfo.getName().getAsString() + " = ");
      }

      Diag(UsingLoc, diag::note_using_decl_class_member_workaround)
        << 2 // reference declaration
        << FixIt;
    } else if (R->getAsSingle<EnumConstantDecl>()) {
      // Don't provide a fixit outside C++11 mode; we don't want to suggest
      // repeating the type of the enumeration here, and we can't do so if
      // the type is anonymous.
      FixItHint FixIt;
      if (getLangOpts().CPlusPlus11) {
        // Convert 'using X::Y;' to 'auto &Y = X::Y;'.
        FixIt = FixItHint::CreateReplacement(
            UsingLoc,
            "constexpr auto " + NameInfo.getName().getAsString() + " = ");
      }

      Diag(UsingLoc, diag::note_using_decl_class_member_workaround)
        << (getLangOpts().CPlusPlus11 ? 4 : 3) // const[expr] variable
        << FixIt;
    }
  }

  return true; // Fail
}

// If the named context is dependent, we can't decide much.
if (!NamedContext) {
  // FIXME: in C++0x, we can diagnose if we can prove that the
  // nested-name-specifier does not refer to a base class, which is
  // still possible in some cases.

  // Otherwise we have to conservatively report that things might be
  // okay.
  return false;
}

// The current scope is a record.
if (!NamedContext->isRecord()) {
  // Ideally this would point at the last name in the specifier,
  // but we don't have that level of source info.
  Diag(SS.getBeginLoc(),
       Cxx20Enumerator
           ? diag::warn_cxx17_compat_using_decl_non_member_enumerator
           : diag::err_using_decl_nested_name_specifier_is_not_class)
      << SS.getScopeRep() << SS.getRange();

  if (Cxx20Enumerator)
    return false; // OK

  return true;
}

if (!NamedContext->isDependentContext() &&
    RequireCompleteDeclContext(const_cast<CXXScopeSpec&>(SS), NamedContext))
  return true;

if (getLangOpts().CPlusPlus11) {
  // C++11 [namespace.udecl]p3:
  //   In a using-declaration used as a member-declaration, the
  //   nested-name-specifier shall name a base class of the class
  //   being defined.

  if (cast<CXXRecordDecl>(CurContext)->isProvablyNotDerivedFrom(
                               cast<CXXRecordDecl>(NamedContext))) {

    if (Cxx20Enumerator) {
      Diag(NameLoc, diag::warn_cxx17_compat_using_decl_non_member_enumerator)
          << SS.getRange();
      return false;
    }

    if (CurContext == NamedContext) {
      Diag(SS.getBeginLoc(),
           diag::err_using_decl_nested_name_specifier_is_current_class)
          << SS.getRange();
      return !getLangOpts().CPlusPlus20;
    }

    if (!cast<CXXRecordDecl>(NamedContext)->isInvalidDecl()) {
      Diag(SS.getBeginLoc(),
           diag::err_using_decl_nested_name_specifier_is_not_base_class)
          << SS.getScopeRep() << cast<CXXRecordDecl>(CurContext)
          << SS.getRange();
    }
    return true;
  }

  return false;
}

// C++03 [namespace.udecl]p4:
//   A using-declaration used as a member-declaration shall refer
//   to a member of a base class of the class being defined [etc.].

// Salient point: SS doesn't have to name a base class as long as
// lookup only finds members from base classes.  Therefore we can
// diagnose here only if we can prove that that can't happen,
// i.e. if the class hierarchies provably don't intersect.

// TODO: it would be nice if "definitely valid" results were cached
// in the UsingDecl and UsingShadowDecl so that these checks didn't
// need to be repeated.

llvm::SmallPtrSet<const CXXRecordDecl *, 4> Bases;
auto Collect = [&Bases](const CXXRecordDecl *Base) {
  Bases.insert(Base);
  return true;
};

// Collect all bases. Return false if we find a dependent base.
if (!cast<CXXRecordDecl>(CurContext)->forallBases(Collect))
  return false;

// Returns true if the base is dependent or is one of the accumulated base
// classes.
auto IsNotBase = [&Bases](const CXXRecordDecl *Base) {
  return !Bases.count(Base);
};

// Return false if the class has a dependent base or if it or one
// of its bases is present in the base set of the current context.
if (Bases.count(cast<CXXRecordDecl>(NamedContext)) ||
    !cast<CXXRecordDecl>(NamedContext)->forallBases(IsNotBase))
  return false;

Diag(SS.getRange().getBegin(),
     diag::err_using_decl_nested_name_specifier_is_not_base_class)
  << SS.getScopeRep()
  << cast<CXXRecordDecl>(CurContext)
  << SS.getRange();

return true;
12747}

12749Decl *Sema::ActOnAliasDeclaration(Scope *S, AccessSpecifier AS,
                                MultiTemplateParamsArg TemplateParamLists,
                                SourceLocation UsingLoc, UnqualifiedId &Name,
                                const ParsedAttributesView &AttrList,
                                TypeResult Type, Decl *DeclFromDeclSpec) {
// Skip up to the relevant declaration scope.
while (S->isTemplateParamScope())
  S = S->getParent();
assert((S->getFlags() & Scope::DeclScope) &&((void)0)
       "got alias-declaration outside of declaration scope")((void)0);

if (Type.isInvalid())
  return nullptr;

bool Invalid = false;
DeclarationNameInfo NameInfo = GetNameFromUnqualifiedId(Name);
TypeSourceInfo *TInfo = nullptr;
GetTypeFromParser(Type.get(), &TInfo);

if (DiagnoseClassNameShadow(CurContext, NameInfo))
  return nullptr;

if (DiagnoseUnexpandedParameterPack(Name.StartLocation, TInfo,
                                    UPPC_DeclarationType)) {
  Invalid = true;
  TInfo = Context.getTrivialTypeSourceInfo(Context.IntTy,
                                           TInfo->getTypeLoc().getBeginLoc());
}

LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
                      TemplateParamLists.size()
                          ? forRedeclarationInCurContext()
                          : ForVisibleRedeclaration);
LookupName(Previous, S);

// Warn about shadowing the name of a template parameter.
if (Previous.isSingleResult() &&
    Previous.getFoundDecl()->isTemplateParameter()) {
  DiagnoseTemplateParameterShadow(Name.StartLocation,Previous.getFoundDecl());
  Previous.clear();
}

assert(Name.Kind == UnqualifiedIdKind::IK_Identifier &&((void)0)
       "name in alias declaration must be an identifier")((void)0);
TypeAliasDecl *NewTD = TypeAliasDecl::Create(Context, CurContext, UsingLoc,
                                             Name.StartLocation,
                                             Name.Identifier, TInfo);

NewTD->setAccess(AS);

if (Invalid)
  NewTD->setInvalidDecl();

ProcessDeclAttributeList(S, NewTD, AttrList);
AddPragmaAttributes(S, NewTD);

CheckTypedefForVariablyModifiedType(S, NewTD);
Invalid |= NewTD->isInvalidDecl();

bool Redeclaration = false;

NamedDecl *NewND;
if (TemplateParamLists.size()) {
  TypeAliasTemplateDecl *OldDecl = nullptr;
  TemplateParameterList *OldTemplateParams = nullptr;

  if (TemplateParamLists.size() != 1) {
    Diag(UsingLoc, diag::err_alias_template_extra_headers)
      << SourceRange(TemplateParamLists[1]->getTemplateLoc(),
       TemplateParamLists[TemplateParamLists.size()-1]->getRAngleLoc());
  }
  TemplateParameterList *TemplateParams = TemplateParamLists[0];

  // Check that we can declare a template here.
  if (CheckTemplateDeclScope(S, TemplateParams))
    return nullptr;

  // Only consider previous declarations in the same scope.
  FilterLookupForScope(Previous, CurContext, S, /*ConsiderLinkage*/false,
                       /*ExplicitInstantiationOrSpecialization*/false);
  if (!Previous.empty()) {
    Redeclaration = true;

    OldDecl = Previous.getAsSingle<TypeAliasTemplateDecl>();
    if (!OldDecl && !Invalid) {
      Diag(UsingLoc, diag::err_redefinition_different_kind)
        << Name.Identifier;

      NamedDecl *OldD = Previous.getRepresentativeDecl();
      if (OldD->getLocation().isValid())
        Diag(OldD->getLocation(), diag::note_previous_definition);

      Invalid = true;
    }

    if (!Invalid && OldDecl && !OldDecl->isInvalidDecl()) {
      if (TemplateParameterListsAreEqual(TemplateParams,
                                         OldDecl->getTemplateParameters(),
                                         /*Complain=*/true,
                                         TPL_TemplateMatch))
        OldTemplateParams =
            OldDecl->getMostRecentDecl()->getTemplateParameters();
      else
        Invalid = true;

      TypeAliasDecl *OldTD = OldDecl->getTemplatedDecl();
      if (!Invalid &&
          !Context.hasSameType(OldTD->getUnderlyingType(),
                               NewTD->getUnderlyingType())) {
        // FIXME: The C++0x standard does not clearly say this is ill-formed,
        // but we can't reasonably accept it.
        Diag(NewTD->getLocation(), diag::err_redefinition_different_typedef)
          << 2 << NewTD->getUnderlyingType() << OldTD->getUnderlyingType();
        if (OldTD->getLocation().isValid())
          Diag(OldTD->getLocation(), diag::note_previous_definition);
        Invalid = true;
      }
    }
  }

  // Merge any previous default template arguments into our parameters,
  // and check the parameter list.
  if (CheckTemplateParameterList(TemplateParams, OldTemplateParams,
                                 TPC_TypeAliasTemplate))
    return nullptr;

  TypeAliasTemplateDecl *NewDecl =
    TypeAliasTemplateDecl::Create(Context, CurContext, UsingLoc,
                                  Name.Identifier, TemplateParams,
                                  NewTD);
  NewTD->setDescribedAliasTemplate(NewDecl);

  NewDecl->setAccess(AS);

  if (Invalid)
    NewDecl->setInvalidDecl();
  else if (OldDecl) {
    NewDecl->setPreviousDecl(OldDecl);
    CheckRedeclarationModuleOwnership(NewDecl, OldDecl);
  }

  NewND = NewDecl;
} else {
  if (auto *TD = dyn_cast_or_null<TagDecl>(DeclFromDeclSpec)) {
    setTagNameForLinkagePurposes(TD, NewTD);
    handleTagNumbering(TD, S);
  }
  ActOnTypedefNameDecl(S, CurContext, NewTD, Previous, Redeclaration);
  NewND = NewTD;
}

PushOnScopeChains(NewND, S);
ActOnDocumentableDecl(NewND);
return NewND;
12903}

12905Decl *Sema::ActOnNamespaceAliasDef(Scope *S, SourceLocation NamespaceLoc,
                                 SourceLocation AliasLoc,
                                 IdentifierInfo *Alias, CXXScopeSpec &SS,
                                 SourceLocation IdentLoc,
                                 IdentifierInfo *Ident) {

// Lookup the namespace name.
LookupResult R(*this, Ident, IdentLoc, LookupNamespaceName);
LookupParsedName(R, S, &SS);

if (R.isAmbiguous())
  return nullptr;

if (R.empty()) {
  if (!TryNamespaceTypoCorrection(*this, R, S, SS, IdentLoc, Ident)) {
    Diag(IdentLoc, diag::err_expected_namespace_name) << SS.getRange();
    return nullptr;
  }
}
assert(!R.isAmbiguous() && !R.empty())((void)0);
NamedDecl *ND = R.getRepresentativeDecl();

// Check if we have a previous declaration with the same name.
LookupResult PrevR(*this, Alias, AliasLoc, LookupOrdinaryName,
                   ForVisibleRedeclaration);
LookupName(PrevR, S);

// Check we're not shadowing a template parameter.
if (PrevR.isSingleResult() && PrevR.getFoundDecl()->isTemplateParameter()) {
  DiagnoseTemplateParameterShadow(AliasLoc, PrevR.getFoundDecl());
  PrevR.clear();
}

// Filter out any other lookup result from an enclosing scope.
FilterLookupForScope(PrevR, CurContext, S, /*ConsiderLinkage*/false,
                     /*AllowInlineNamespace*/false);

// Find the previous declaration and check that we can redeclare it.
NamespaceAliasDecl *Prev = nullptr;
if (PrevR.isSingleResult()) {
  NamedDecl *PrevDecl = PrevR.getRepresentativeDecl();
  if (NamespaceAliasDecl *AD = dyn_cast<NamespaceAliasDecl>(PrevDecl)) {
    // We already have an alias with the same name that points to the same
    // namespace; check that it matches.
    if (AD->getNamespace()->Equals(getNamespaceDecl(ND))) {
      Prev = AD;
    } else if (isVisible(PrevDecl)) {
      Diag(AliasLoc, diag::err_redefinition_different_namespace_alias)
        << Alias;
      Diag(AD->getLocation(), diag::note_previous_namespace_alias)
        << AD->getNamespace();
      return nullptr;
    }
  } else if (isVisible(PrevDecl)) {
    unsigned DiagID = isa<NamespaceDecl>(PrevDecl->getUnderlyingDecl())
                          ? diag::err_redefinition
                          : diag::err_redefinition_different_kind;
    Diag(AliasLoc, DiagID) << Alias;
    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
    return nullptr;
  }
}

// The use of a nested name specifier may trigger deprecation warnings.
DiagnoseUseOfDecl(ND, IdentLoc);

NamespaceAliasDecl *AliasDecl =
  NamespaceAliasDecl::Create(Context, CurContext, NamespaceLoc, AliasLoc,
                             Alias, SS.getWithLocInContext(Context),
                             IdentLoc, ND);
if (Prev)
  AliasDecl->setPreviousDecl(Prev);

PushOnScopeChains(AliasDecl, S);
return AliasDecl;
12980}

12982namespace {
12983struct SpecialMemberExceptionSpecInfo
  : SpecialMemberVisitor<SpecialMemberExceptionSpecInfo> {
SourceLocation Loc;
Sema::ImplicitExceptionSpecification ExceptSpec;

SpecialMemberExceptionSpecInfo(Sema &S, CXXMethodDecl *MD,
                               Sema::CXXSpecialMember CSM,
                               Sema::InheritedConstructorInfo *ICI,
                               SourceLocation Loc)
    : SpecialMemberVisitor(S, MD, CSM, ICI), Loc(Loc), ExceptSpec(S) {}

bool visitBase(CXXBaseSpecifier *Base);
bool visitField(FieldDecl *FD);

void visitClassSubobject(CXXRecordDecl *Class, Subobject Subobj,
                         unsigned Quals);

void visitSubobjectCall(Subobject Subobj,
                        Sema::SpecialMemberOverloadResult SMOR);
13002};
13003}

13005bool SpecialMemberExceptionSpecInfo::visitBase(CXXBaseSpecifier *Base) {
auto *RT = Base->getType()->getAs<RecordType>();
if (!RT)
  return false;

auto *BaseClass = cast<CXXRecordDecl>(RT->getDecl());
Sema::SpecialMemberOverloadResult SMOR = lookupInheritedCtor(BaseClass);
if (auto *BaseCtor = SMOR.getMethod()) {
  visitSubobjectCall(Base, BaseCtor);
  return false;
}

visitClassSubobject(BaseClass, Base, 0);
return false;
13019}

13021bool SpecialMemberExceptionSpecInfo::visitField(FieldDecl *FD) {
if (CSM == Sema::CXXDefaultConstructor && FD->hasInClassInitializer()) {
  Expr *E = FD->getInClassInitializer();
  if (!E)
    // FIXME: It's a little wasteful to build and throw away a
    // CXXDefaultInitExpr here.
    // FIXME: We should have a single context note pointing at Loc, and
    // this location should be MD->getLocation() instead, since that's
    // the location where we actually use the default init expression.
    E = S.BuildCXXDefaultInitExpr(Loc, FD).get();
  if (E)
    ExceptSpec.CalledExpr(E);
} else if (auto *RT = S.Context.getBaseElementType(FD->getType())
                          ->getAs<RecordType>()) {
  visitClassSubobject(cast<CXXRecordDecl>(RT->getDecl()), FD,
                      FD->getType().getCVRQualifiers());
}
return false;
13039}

13041void SpecialMemberExceptionSpecInfo::visitClassSubobject(CXXRecordDecl *Class,
                                                       Subobject Subobj,
                                                       unsigned Quals) {
FieldDecl *Field = Subobj.dyn_cast<FieldDecl*>();
bool IsMutable = Field && Field->isMutable();
visitSubobjectCall(Subobj, lookupIn(Class, Quals, IsMutable));
13047}

13049void SpecialMemberExceptionSpecInfo::visitSubobjectCall(
  Subobject Subobj, Sema::SpecialMemberOverloadResult SMOR) {
// Note, if lookup fails, it doesn't matter what exception specification we
// choose because the special member will be deleted.
if (CXXMethodDecl *MD = SMOR.getMethod())
  ExceptSpec.CalledDecl(getSubobjectLoc(Subobj), MD);
13055}

13057bool Sema::tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec) {
llvm::APSInt Result;
ExprResult Converted = CheckConvertedConstantExpression(
    ExplicitSpec.getExpr(), Context.BoolTy, Result, CCEK_ExplicitBool);
ExplicitSpec.setExpr(Converted.get());
if (Converted.isUsable() && !Converted.get()->isValueDependent()) {
  ExplicitSpec.setKind(Result.getBoolValue()
                           ? ExplicitSpecKind::ResolvedTrue
                           : ExplicitSpecKind::ResolvedFalse);
  return true;
}
ExplicitSpec.setKind(ExplicitSpecKind::Unresolved);
return false;
13070}

13072ExplicitSpecifier Sema::ActOnExplicitBoolSpecifier(Expr *ExplicitExpr) {
ExplicitSpecifier ES(ExplicitExpr, ExplicitSpecKind::Unresolved);
if (!ExplicitExpr->isTypeDependent())
  tryResolveExplicitSpecifier(ES);
return ES;
13077}

13079static Sema::ImplicitExceptionSpecification
13080ComputeDefaultedSpecialMemberExceptionSpec(
  Sema &S, SourceLocation Loc, CXXMethodDecl *MD, Sema::CXXSpecialMember CSM,
  Sema::InheritedConstructorInfo *ICI) {
ComputingExceptionSpec CES(S, MD, Loc);

CXXRecordDecl *ClassDecl = MD->getParent();

// C++ [except.spec]p14:
//   An implicitly declared special member function (Clause 12) shall have an
//   exception-specification. [...]
SpecialMemberExceptionSpecInfo Info(S, MD, CSM, ICI, MD->getLocation());
if (ClassDecl->isInvalidDecl())
  return Info.ExceptSpec;

// FIXME: If this diagnostic fires, we're probably missing a check for
// attempting to resolve an exception specification before it's known
// at a higher level.
if (S.RequireCompleteType(MD->getLocation(),
                          S.Context.getRecordType(ClassDecl),
                          diag::err_exception_spec_incomplete_type))
  return Info.ExceptSpec;

// C++1z [except.spec]p7:
//   [Look for exceptions thrown by] a constructor selected [...] to
//   initialize a potentially constructed subobject,
// C++1z [except.spec]p8:
//   The exception specification for an implicitly-declared destructor, or a
//   destructor without a noexcept-specifier, is potentially-throwing if and
//   only if any of the destructors for any of its potentially constructed
//   subojects is potentially throwing.
// FIXME: We respect the first rule but ignore the "potentially constructed"
// in the second rule to resolve a core issue (no number yet) that would have
// us reject:
//   struct A { virtual void f() = 0; virtual ~A() noexcept(false) = 0; };
//   struct B : A {};
//   struct C : B { void f(); };
// ... due to giving B::~B() a non-throwing exception specification.
Info.visit(Info.IsConstructor ? Info.VisitPotentiallyConstructedBases
                              : Info.VisitAllBases);

return Info.ExceptSpec;
13121}

13123namespace {
13124/// RAII object to register a special member as being currently declared.
13125struct DeclaringSpecialMember {
Sema &S;
Sema::SpecialMemberDecl D;
Sema::ContextRAII SavedContext;
bool WasAlreadyBeingDeclared;

DeclaringSpecialMember(Sema &S, CXXRecordDecl *RD, Sema::CXXSpecialMember CSM)
    : S(S), D(RD, CSM), SavedContext(S, RD) {
  WasAlreadyBeingDeclared = !S.SpecialMembersBeingDeclared.insert(D).second;
  if (WasAlreadyBeingDeclared)
    // This almost never happens, but if it does, ensure that our cache
    // doesn't contain a stale result.
    S.SpecialMemberCache.clear();
  else {
    // Register a note to be produced if we encounter an error while
    // declaring the special member.
    Sema::CodeSynthesisContext Ctx;
    Ctx.Kind = Sema::CodeSynthesisContext::DeclaringSpecialMember;
    // FIXME: We don't have a location to use here. Using the class's
    // location maintains the fiction that we declare all special members
    // with the class, but (1) it's not clear that lying about that helps our
    // users understand what's going on, and (2) there may be outer contexts
    // on the stack (some of which are relevant) and printing them exposes
    // our lies.
    Ctx.PointOfInstantiation = RD->getLocation();
    Ctx.Entity = RD;
    Ctx.SpecialMember = CSM;
    S.pushCodeSynthesisContext(Ctx);
  }
}
~DeclaringSpecialMember() {
  if (!WasAlreadyBeingDeclared) {
    S.SpecialMembersBeingDeclared.erase(D);
    S.popCodeSynthesisContext();
  }
}

/// Are we already trying to declare this special member?
bool isAlreadyBeingDeclared() const {
  return WasAlreadyBeingDeclared;
}
13166};
13167}

13169void Sema::CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD) {
// Look up any existing declarations, but don't trigger declaration of all
// implicit special members with this name.
DeclarationName Name = FD->getDeclName();
LookupResult R(*this, Name, SourceLocation(), LookupOrdinaryName,
               ForExternalRedeclaration);
for (auto *D : FD->getParent()->lookup(Name))
  if (auto *Acceptable = R.getAcceptableDecl(D))
    R.addDecl(Acceptable);
R.resolveKind();
R.suppressDiagnostics();

CheckFunctionDeclaration(S, FD, R, /*IsMemberSpecialization*/false);
13182}

13184void Sema::setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
                                        QualType ResultTy,
                                        ArrayRef<QualType> Args) {
// Build an exception specification pointing back at this constructor.
FunctionProtoType::ExtProtoInfo EPI = getImplicitMethodEPI(*this, SpecialMem);

LangAS AS = getDefaultCXXMethodAddrSpace();
if (AS != LangAS::Default) {
  EPI.TypeQuals.addAddressSpace(AS);
}

auto QT = Context.getFunctionType(ResultTy, Args, EPI);
SpecialMem->setType(QT);

// During template instantiation of implicit special member functions we need
// a reliable TypeSourceInfo for the function prototype in order to allow
// functions to be substituted.
if (inTemplateInstantiation() &&
    cast<CXXRecordDecl>(SpecialMem->getParent())->isLambda()) {
  TypeSourceInfo *TSI =
      Context.getTrivialTypeSourceInfo(SpecialMem->getType());
  SpecialMem->setTypeSourceInfo(TSI);
}
13207}

13209CXXConstructorDecl *Sema::DeclareImplicitDefaultConstructor(
                                                   CXXRecordDecl *ClassDecl) {
// C++ [class.ctor]p5:
//   A default constructor for a class X is a constructor of class X
//   that can be called without an argument. If there is no
//   user-declared constructor for class X, a default constructor is
//   implicitly declared. An implicitly-declared default constructor
//   is an inline public member of its class.
assert(ClassDecl->needsImplicitDefaultConstructor() &&((void)0)
       "Should not build implicit default constructor!")((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXDefaultConstructor);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXDefaultConstructor,
                                                   false);

// Create the actual constructor declaration.
CanQualType ClassType
  = Context.getCanonicalType(Context.getTypeDeclType(ClassDecl));
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationName Name
  = Context.DeclarationNames.getCXXConstructorName(ClassType);
DeclarationNameInfo NameInfo(Name, ClassLoc);
CXXConstructorDecl *DefaultCon = CXXConstructorDecl::Create(
    Context, ClassDecl, ClassLoc, NameInfo, /*Type*/ QualType(),
    /*TInfo=*/nullptr, ExplicitSpecifier(),
    /*isInline=*/true, /*isImplicitlyDeclared=*/true,
    Constexpr ? ConstexprSpecKind::Constexpr
              : ConstexprSpecKind::Unspecified);
DefaultCon->setAccess(AS_public);
DefaultCon->setDefaulted();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXDefaultConstructor,
                                          DefaultCon,
                                          /* ConstRHS */ false,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(DefaultCon, Context.VoidTy, None);

// We don't need to use SpecialMemberIsTrivial here; triviality for default
// constructors is easy to compute.
DefaultCon->setTrivial(ClassDecl->hasTrivialDefaultConstructor());

// Note that we have declared this constructor.
++getASTContext().NumImplicitDefaultConstructorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, DefaultCon);

if (ShouldDeleteSpecialMember(DefaultCon, CXXDefaultConstructor))
  SetDeclDeleted(DefaultCon, ClassLoc);

if (S)
  PushOnScopeChains(DefaultCon, S, false);
ClassDecl->addDecl(DefaultCon);

return DefaultCon;
13271}

13273void Sema::DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
                                          CXXConstructorDecl *Constructor) {
assert((Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&((void)0)
        !Constructor->doesThisDeclarationHaveABody() &&((void)0)
        !Constructor->isDeleted()) &&((void)0)
  "DefineImplicitDefaultConstructor - call it for implicit default ctor")((void)0);
if (Constructor->willHaveBody() || Constructor->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = Constructor->getParent();
assert(ClassDecl && "DefineImplicitDefaultConstructor - invalid constructor")((void)0);

SynthesizedFunctionScope Scope(*this, Constructor);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     Constructor->getType()->castAs<FunctionProtoType>());
MarkVTableUsed(CurrentLocation, ClassDecl);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

if (SetCtorInitializers(Constructor, /*AnyErrors=*/false)) {
  Constructor->setInvalidDecl();
  return;
}

SourceLocation Loc = Constructor->getEndLoc().isValid()
                         ? Constructor->getEndLoc()
                         : Constructor->getLocation();
Constructor->setBody(new (Context) CompoundStmt(Loc));
Constructor->markUsed(Context);

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(Constructor);
}

DiagnoseUninitializedFields(*this, Constructor);
13312}

13314void Sema::ActOnFinishDelayedMemberInitializers(Decl *D) {
// Perform any delayed checks on exception specifications.
CheckDelayedMemberExceptionSpecs();
13317}

13319/// Find or create the fake constructor we synthesize to model constructing an
13320/// object of a derived class via a constructor of a base class.
13321CXXConstructorDecl *
13322Sema::findInheritingConstructor(SourceLocation Loc,
                              CXXConstructorDecl *BaseCtor,
                              ConstructorUsingShadowDecl *Shadow) {
CXXRecordDecl *Derived = Shadow->getParent();
SourceLocation UsingLoc = Shadow->getLocation();

// FIXME: Add a new kind of DeclarationName for an inherited constructor.
// For now we use the name of the base class constructor as a member of the
// derived class to indicate a (fake) inherited constructor name.
DeclarationName Name = BaseCtor->getDeclName();

// Check to see if we already have a fake constructor for this inherited
// constructor call.
for (NamedDecl *Ctor : Derived->lookup(Name))
  if (declaresSameEntity(cast<CXXConstructorDecl>(Ctor)
                             ->getInheritedConstructor()
                             .getConstructor(),
                         BaseCtor))
    return cast<CXXConstructorDecl>(Ctor);

DeclarationNameInfo NameInfo(Name, UsingLoc);
TypeSourceInfo *TInfo =
    Context.getTrivialTypeSourceInfo(BaseCtor->getType(), UsingLoc);
FunctionProtoTypeLoc ProtoLoc =
    TInfo->getTypeLoc().IgnoreParens().castAs<FunctionProtoTypeLoc>();

// Check the inherited constructor is valid and find the list of base classes
// from which it was inherited.
InheritedConstructorInfo ICI(*this, Loc, Shadow);

bool Constexpr =
    BaseCtor->isConstexpr() &&
    defaultedSpecialMemberIsConstexpr(*this, Derived, CXXDefaultConstructor,
                                      false, BaseCtor, &ICI);

CXXConstructorDecl *DerivedCtor = CXXConstructorDecl::Create(
    Context, Derived, UsingLoc, NameInfo, TInfo->getType(), TInfo,
    BaseCtor->getExplicitSpecifier(), /*isInline=*/true,
    /*isImplicitlyDeclared=*/true,
    Constexpr ? BaseCtor->getConstexprKind() : ConstexprSpecKind::Unspecified,
    InheritedConstructor(Shadow, BaseCtor),
    BaseCtor->getTrailingRequiresClause());
if (Shadow->isInvalidDecl())
  DerivedCtor->setInvalidDecl();

// Build an unevaluated exception specification for this fake constructor.
const FunctionProtoType *FPT = TInfo->getType()->castAs<FunctionProtoType>();
FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
EPI.ExceptionSpec.Type = EST_Unevaluated;
EPI.ExceptionSpec.SourceDecl = DerivedCtor;
DerivedCtor->setType(Context.getFunctionType(FPT->getReturnType(),
                                             FPT->getParamTypes(), EPI));

// Build the parameter declarations.
SmallVector<ParmVarDecl *, 16> ParamDecls;
for (unsigned I = 0, N = FPT->getNumParams(); I != N; ++I) {
  TypeSourceInfo *TInfo =
      Context.getTrivialTypeSourceInfo(FPT->getParamType(I), UsingLoc);
  ParmVarDecl *PD = ParmVarDecl::Create(
      Context, DerivedCtor, UsingLoc, UsingLoc, /*IdentifierInfo=*/nullptr,
      FPT->getParamType(I), TInfo, SC_None, /*DefArg=*/nullptr);
  PD->setScopeInfo(0, I);
  PD->setImplicit();
  // Ensure attributes are propagated onto parameters (this matters for
  // format, pass_object_size, ...).
  mergeDeclAttributes(PD, BaseCtor->getParamDecl(I));
  ParamDecls.push_back(PD);
  ProtoLoc.setParam(I, PD);
}

// Set up the new constructor.
assert(!BaseCtor->isDeleted() && "should not use deleted constructor")((void)0);
DerivedCtor->setAccess(BaseCtor->getAccess());
DerivedCtor->setParams(ParamDecls);
Derived->addDecl(DerivedCtor);

if (ShouldDeleteSpecialMember(DerivedCtor, CXXDefaultConstructor, &ICI))
  SetDeclDeleted(DerivedCtor, UsingLoc);

return DerivedCtor;
13402}

13404void Sema::NoteDeletedInheritingConstructor(CXXConstructorDecl *Ctor) {
InheritedConstructorInfo ICI(*this, Ctor->getLocation(),
                             Ctor->getInheritedConstructor().getShadowDecl());
ShouldDeleteSpecialMember(Ctor, CXXDefaultConstructor, &ICI,
                          /*Diagnose*/true);
13409}

13411void Sema::DefineInheritingConstructor(SourceLocation CurrentLocation,
                                     CXXConstructorDecl *Constructor) {
CXXRecordDecl *ClassDecl = Constructor->getParent();
assert(Constructor->getInheritedConstructor() &&((void)0)
       !Constructor->doesThisDeclarationHaveABody() &&((void)0)
       !Constructor->isDeleted())((void)0);
if (Constructor->willHaveBody() || Constructor->isInvalidDecl())
  return;

// Initializations are performed "as if by a defaulted default constructor",
// so enter the appropriate scope.
SynthesizedFunctionScope Scope(*this, Constructor);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     Constructor->getType()->castAs<FunctionProtoType>());
MarkVTableUsed(CurrentLocation, ClassDecl);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

ConstructorUsingShadowDecl *Shadow =
    Constructor->getInheritedConstructor().getShadowDecl();
CXXConstructorDecl *InheritedCtor =
    Constructor->getInheritedConstructor().getConstructor();

// [class.inhctor.init]p1:
//   initialization proceeds as if a defaulted default constructor is used to
//   initialize the D object and each base class subobject from which the
//   constructor was inherited

InheritedConstructorInfo ICI(*this, CurrentLocation, Shadow);
CXXRecordDecl *RD = Shadow->getParent();
SourceLocation InitLoc = Shadow->getLocation();

// Build explicit initializers for all base classes from which the
// constructor was inherited.
SmallVector<CXXCtorInitializer*, 8> Inits;
for (bool VBase : {false, true}) {
  for (CXXBaseSpecifier &B : VBase ? RD->vbases() : RD->bases()) {
    if (B.isVirtual() != VBase)
      continue;

    auto *BaseRD = B.getType()->getAsCXXRecordDecl();
    if (!BaseRD)
      continue;

    auto BaseCtor = ICI.findConstructorForBase(BaseRD, InheritedCtor);
    if (!BaseCtor.first)
      continue;

    MarkFunctionReferenced(CurrentLocation, BaseCtor.first);
    ExprResult Init = new (Context) CXXInheritedCtorInitExpr(
        InitLoc, B.getType(), BaseCtor.first, VBase, BaseCtor.second);

    auto *TInfo = Context.getTrivialTypeSourceInfo(B.getType(), InitLoc);
    Inits.push_back(new (Context) CXXCtorInitializer(
        Context, TInfo, VBase, InitLoc, Init.get(), InitLoc,
        SourceLocation()));
  }
}

// We now proceed as if for a defaulted default constructor, with the relevant
// initializers replaced.

if (SetCtorInitializers(Constructor, /*AnyErrors*/false, Inits)) {
  Constructor->setInvalidDecl();
  return;
}

Constructor->setBody(new (Context) CompoundStmt(InitLoc));
Constructor->markUsed(Context);

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(Constructor);
}

DiagnoseUninitializedFields(*this, Constructor);
13490}

13492CXXDestructorDecl *Sema::DeclareImplicitDestructor(CXXRecordDecl *ClassDecl) {
// C++ [class.dtor]p2:
//   If a class has no user-declared destructor, a destructor is
//   declared implicitly. An implicitly-declared destructor is an
//   inline public member of its class.
assert(ClassDecl->needsImplicitDestructor())((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXDestructor);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXDestructor,
                                                   false);

// Create the actual destructor declaration.
CanQualType ClassType
  = Context.getCanonicalType(Context.getTypeDeclType(ClassDecl));
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationName Name
  = Context.DeclarationNames.getCXXDestructorName(ClassType);
DeclarationNameInfo NameInfo(Name, ClassLoc);
CXXDestructorDecl *Destructor =
    CXXDestructorDecl::Create(Context, ClassDecl, ClassLoc, NameInfo,
                              QualType(), nullptr, /*isInline=*/true,
                              /*isImplicitlyDeclared=*/true,
                              Constexpr ? ConstexprSpecKind::Constexpr
                                        : ConstexprSpecKind::Unspecified);
Destructor->setAccess(AS_public);
Destructor->setDefaulted();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXDestructor,
                                          Destructor,
                                          /* ConstRHS */ false,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(Destructor, Context.VoidTy, None);

// We don't need to use SpecialMemberIsTrivial here; triviality for
// destructors is easy to compute.
Destructor->setTrivial(ClassDecl->hasTrivialDestructor());
Destructor->setTrivialForCall(ClassDecl->hasAttr<TrivialABIAttr>() ||
                              ClassDecl->hasTrivialDestructorForCall());

// Note that we have declared this destructor.
++getASTContext().NumImplicitDestructorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, Destructor);

// We can't check whether an implicit destructor is deleted before we complete
// the definition of the class, because its validity depends on the alignment
// of the class. We'll check this from ActOnFields once the class is complete.
if (ClassDecl->isCompleteDefinition() &&
    ShouldDeleteSpecialMember(Destructor, CXXDestructor))
  SetDeclDeleted(Destructor, ClassLoc);

// Introduce this destructor into its scope.
if (S)
  PushOnScopeChains(Destructor, S, false);
ClassDecl->addDecl(Destructor);

return Destructor;
13557}

13559void Sema::DefineImplicitDestructor(SourceLocation CurrentLocation,
                                  CXXDestructorDecl *Destructor) {
assert((Destructor->isDefaulted() &&((void)0)
        !Destructor->doesThisDeclarationHaveABody() &&((void)0)
        !Destructor->isDeleted()) &&((void)0)
       "DefineImplicitDestructor - call it for implicit default dtor")((void)0);
if (Destructor->willHaveBody() || Destructor->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = Destructor->getParent();
assert(ClassDecl && "DefineImplicitDestructor - invalid destructor")((void)0);

SynthesizedFunctionScope Scope(*this, Destructor);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     Destructor->getType()->castAs<FunctionProtoType>());
MarkVTableUsed(CurrentLocation, ClassDecl);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

MarkBaseAndMemberDestructorsReferenced(Destructor->getLocation(),
                                       Destructor->getParent());

if (CheckDestructor(Destructor)) {
  Destructor->setInvalidDecl();
  return;
}

SourceLocation Loc = Destructor->getEndLoc().isValid()
                         ? Destructor->getEndLoc()
                         : Destructor->getLocation();
Destructor->setBody(new (Context) CompoundStmt(Loc));
Destructor->markUsed(Context);

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(Destructor);
}
13599}

13601void Sema::CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
                                        CXXDestructorDecl *Destructor) {
if (Destructor->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = Destructor->getParent();
assert(Context.getTargetInfo().getCXXABI().isMicrosoft() &&((void)0)
       "implicit complete dtors unneeded outside MS ABI")((void)0);
assert(ClassDecl->getNumVBases() > 0 &&((void)0)
       "complete dtor only exists for classes with vbases")((void)0);

SynthesizedFunctionScope Scope(*this, Destructor);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

MarkVirtualBaseDestructorsReferenced(Destructor->getLocation(), ClassDecl);
13618}

13620/// Perform any semantic analysis which needs to be delayed until all
13621/// pending class member declarations have been parsed.
13622void Sema::ActOnFinishCXXMemberDecls() {
// If the context is an invalid C++ class, just suppress these checks.
if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(CurContext)) {
  if (Record->isInvalidDecl()) {
    DelayedOverridingExceptionSpecChecks.clear();
    DelayedEquivalentExceptionSpecChecks.clear();
    return;
  }
  checkForMultipleExportedDefaultConstructors(*this, Record);
}
13632}

13634void Sema::ActOnFinishCXXNonNestedClass() {
referenceDLLExportedClassMethods();

if (!DelayedDllExportMemberFunctions.empty()) {
  SmallVector<CXXMethodDecl*, 4> WorkList;
  std::swap(DelayedDllExportMemberFunctions, WorkList);
  for (CXXMethodDecl *M : WorkList) {
    DefineDefaultedFunction(*this, M, M->getLocation());

    // Pass the method to the consumer to get emitted. This is not necessary
    // for explicit instantiation definitions, as they will get emitted
    // anyway.
    if (M->getParent()->getTemplateSpecializationKind() !=
        TSK_ExplicitInstantiationDefinition)
      ActOnFinishInlineFunctionDef(M);
  }
}
13651}

13653void Sema::referenceDLLExportedClassMethods() {
if (!DelayedDllExportClasses.empty()) {
  // Calling ReferenceDllExportedMembers might cause the current function to
  // be called again, so use a local copy of DelayedDllExportClasses.
  SmallVector<CXXRecordDecl *, 4> WorkList;
  std::swap(DelayedDllExportClasses, WorkList);
  for (CXXRecordDecl *Class : WorkList)
    ReferenceDllExportedMembers(*this, Class);
}
13662}

13664void Sema::AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor) {
assert(getLangOpts().CPlusPlus11 &&((void)0)
       "adjusting dtor exception specs was introduced in c++11")((void)0);

if (Destructor->isDependentContext())
  return;

// C++11 [class.dtor]p3:
//   A declaration of a destructor that does not have an exception-
//   specification is implicitly considered to have the same exception-
//   specification as an implicit declaration.
const auto *DtorType = Destructor->getType()->castAs<FunctionProtoType>();
if (DtorType->hasExceptionSpec())
  return;

// Replace the destructor's type, building off the existing one. Fortunately,
// the only thing of interest in the destructor type is its extended info.
// The return and arguments are fixed.
FunctionProtoType::ExtProtoInfo EPI = DtorType->getExtProtoInfo();
EPI.ExceptionSpec.Type = EST_Unevaluated;
EPI.ExceptionSpec.SourceDecl = Destructor;
Destructor->setType(Context.getFunctionType(Context.VoidTy, None, EPI));

// FIXME: If the destructor has a body that could throw, and the newly created
// spec doesn't allow exceptions, we should emit a warning, because this
// change in behavior can break conforming C++03 programs at runtime.
// However, we don't have a body or an exception specification yet, so it
// needs to be done somewhere else.
13692}

13694namespace {
13695/// An abstract base class for all helper classes used in building the
13696//  copy/move operators. These classes serve as factory functions and help us
13697//  avoid using the same Expr* in the AST twice.
13698class ExprBuilder {
ExprBuilder(const ExprBuilder&) = delete;
ExprBuilder &operator=(const ExprBuilder&) = delete;

13702protected:
static Expr *assertNotNull(Expr *E) {
  assert(E && "Expression construction must not fail.")((void)0);
  return E;
}

13708public:
ExprBuilder() {}
virtual ~ExprBuilder() {}

virtual Expr *build(Sema &S, SourceLocation Loc) const = 0;
13713};

13715class RefBuilder: public ExprBuilder {
VarDecl *Var;
QualType VarType;

13719public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(S.BuildDeclRefExpr(Var, VarType, VK_LValue, Loc));
}

RefBuilder(VarDecl *Var, QualType VarType)
    : Var(Var), VarType(VarType) {}
13726};

13728class ThisBuilder: public ExprBuilder {
13729public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(S.ActOnCXXThis(Loc).getAs<Expr>());
}
13733};

13735class CastBuilder: public ExprBuilder {
const ExprBuilder &Builder;
QualType Type;
ExprValueKind Kind;
const CXXCastPath &Path;

13741public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(S.ImpCastExprToType(Builder.build(S, Loc), Type,
                                           CK_UncheckedDerivedToBase, Kind,
                                           &Path).get());
}

CastBuilder(const ExprBuilder &Builder, QualType Type, ExprValueKind Kind,
            const CXXCastPath &Path)
    : Builder(Builder), Type(Type), Kind(Kind), Path(Path) {}
13751};

13753class DerefBuilder: public ExprBuilder {
const ExprBuilder &Builder;

13756public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(
      S.CreateBuiltinUnaryOp(Loc, UO_Deref, Builder.build(S, Loc)).get());
}

DerefBuilder(const ExprBuilder &Builder) : Builder(Builder) {}
13763};

13765class MemberBuilder: public ExprBuilder {
const ExprBuilder &Builder;
QualType Type;
CXXScopeSpec SS;
bool IsArrow;
LookupResult &MemberLookup;

13772public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(S.BuildMemberReferenceExpr(
      Builder.build(S, Loc), Type, Loc, IsArrow, SS, SourceLocation(),
      nullptr, MemberLookup, nullptr, nullptr).get());
}

MemberBuilder(const ExprBuilder &Builder, QualType Type, bool IsArrow,
              LookupResult &MemberLookup)
    : Builder(Builder), Type(Type), IsArrow(IsArrow),
      MemberLookup(MemberLookup) {}
13783};

13785class MoveCastBuilder: public ExprBuilder {
const ExprBuilder &Builder;

13788public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(CastForMoving(S, Builder.build(S, Loc)));
}

MoveCastBuilder(const ExprBuilder &Builder) : Builder(Builder) {}
13794};

13796class LvalueConvBuilder: public ExprBuilder {
const ExprBuilder &Builder;

13799public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(
      S.DefaultLvalueConversion(Builder.build(S, Loc)).get());
}

LvalueConvBuilder(const ExprBuilder &Builder) : Builder(Builder) {}
13806};

13808class SubscriptBuilder: public ExprBuilder {
const ExprBuilder &Base;
const ExprBuilder &Index;

13812public:
Expr *build(Sema &S, SourceLocation Loc) const override {
  return assertNotNull(S.CreateBuiltinArraySubscriptExpr(
      Base.build(S, Loc), Loc, Index.build(S, Loc), Loc).get());
}

SubscriptBuilder(const ExprBuilder &Base, const ExprBuilder &Index)
    : Base(Base), Index(Index) {}
13820};

13822} // end anonymous namespace

13824/// When generating a defaulted copy or move assignment operator, if a field
13825/// should be copied with __builtin_memcpy rather than via explicit assignments,
13826/// do so. This optimization only applies for arrays of scalars, and for arrays
13827/// of class type where the selected copy/move-assignment operator is trivial.
13828static StmtResult
13829buildMemcpyForAssignmentOp(Sema &S, SourceLocation Loc, QualType T,
                         const ExprBuilder &ToB, const ExprBuilder &FromB) {
// Compute the size of the memory buffer to be copied.
QualType SizeType = S.Context.getSizeType();
llvm::APInt Size(S.Context.getTypeSize(SizeType),
                 S.Context.getTypeSizeInChars(T).getQuantity());

// Take the address of the field references for "from" and "to". We
// directly construct UnaryOperators here because semantic analysis
// does not permit us to take the address of an xvalue.
Expr *From = FromB.build(S, Loc);
From = UnaryOperator::Create(
    S.Context, From, UO_AddrOf, S.Context.getPointerType(From->getType()),
    VK_PRValue, OK_Ordinary, Loc, false, S.CurFPFeatureOverrides());
Expr *To = ToB.build(S, Loc);
To = UnaryOperator::Create(
    S.Context, To, UO_AddrOf, S.Context.getPointerType(To->getType()),
    VK_PRValue, OK_Ordinary, Loc, false, S.CurFPFeatureOverrides());

const Type *E = T->getBaseElementTypeUnsafe();
bool NeedsCollectableMemCpy =
    E->isRecordType() &&
    E->castAs<RecordType>()->getDecl()->hasObjectMember();

// Create a reference to the __builtin_objc_memmove_collectable function
StringRef MemCpyName = NeedsCollectableMemCpy ?
  "__builtin_objc_memmove_collectable" :
  "__builtin_memcpy";
LookupResult R(S, &S.Context.Idents.get(MemCpyName), Loc,
               Sema::LookupOrdinaryName);
S.LookupName(R, S.TUScope, true);

FunctionDecl *MemCpy = R.getAsSingle<FunctionDecl>();
if (!MemCpy)
  // Something went horribly wrong earlier, and we will have complained
  // about it.
  return StmtError();

ExprResult MemCpyRef = S.BuildDeclRefExpr(MemCpy, S.Context.BuiltinFnTy,
                                          VK_PRValue, Loc, nullptr);
assert(MemCpyRef.isUsable() && "Builtin reference cannot fail")((void)0);

Expr *CallArgs[] = {
  To, From, IntegerLiteral::Create(S.Context, Size, SizeType, Loc)
};
ExprResult Call = S.BuildCallExpr(/*Scope=*/nullptr, MemCpyRef.get(),
                                  Loc, CallArgs, Loc);

assert(!Call.isInvalid() && "Call to __builtin_memcpy cannot fail!")((void)0);
return Call.getAs<Stmt>();
13879}

13881/// Builds a statement that copies/moves the given entity from \p From to
13882/// \c To.
13883///
13884/// This routine is used to copy/move the members of a class with an
13885/// implicitly-declared copy/move assignment operator. When the entities being
13886/// copied are arrays, this routine builds for loops to copy them.
13887///
13888/// \param S The Sema object used for type-checking.
13889///
13890/// \param Loc The location where the implicit copy/move is being generated.
13891///
13892/// \param T The type of the expressions being copied/moved. Both expressions
13893/// must have this type.
13894///
13895/// \param To The expression we are copying/moving to.
13896///
13897/// \param From The expression we are copying/moving from.
13898///
13899/// \param CopyingBaseSubobject Whether we're copying/moving a base subobject.
13900/// Otherwise, it's a non-static member subobject.
13901///
13902/// \param Copying Whether we're copying or moving.
13903///
13904/// \param Depth Internal parameter recording the depth of the recursion.
13905///
13906/// \returns A statement or a loop that copies the expressions, or StmtResult(0)
13907/// if a memcpy should be used instead.
13908static StmtResult
13909buildSingleCopyAssignRecursively(Sema &S, SourceLocation Loc, QualType T,
                               const ExprBuilder &To, const ExprBuilder &From,
                               bool CopyingBaseSubobject, bool Copying,
                               unsigned Depth = 0) {
// C++11 [class.copy]p28:
//   Each subobject is assigned in the manner appropriate to its type:
//
//     - if the subobject is of class type, as if by a call to operator= with
//       the subobject as the object expression and the corresponding
//       subobject of x as a single function argument (as if by explicit
//       qualification; that is, ignoring any possible virtual overriding
//       functions in more derived classes);
//
// C++03 [class.copy]p13:
//     - if the subobject is of class type, the copy assignment operator for
//       the class is used (as if by explicit qualification; that is,
//       ignoring any possible virtual overriding functions in more derived
//       classes);
if (const RecordType *RecordTy = T->getAs<RecordType>()) {
  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RecordTy->getDecl());

  // Look for operator=.
  DeclarationName Name
    = S.Context.DeclarationNames.getCXXOperatorName(OO_Equal);
  LookupResult OpLookup(S, Name, Loc, Sema::LookupOrdinaryName);
  S.LookupQualifiedName(OpLookup, ClassDecl, false);

  // Prior to C++11, filter out any result that isn't a copy/move-assignment
  // operator.
  if (!S.getLangOpts().CPlusPlus11) {
    LookupResult::Filter F = OpLookup.makeFilter();
    while (F.hasNext()) {
      NamedDecl *D = F.next();
      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
        if (Method->isCopyAssignmentOperator() ||
            (!Copying && Method->isMoveAssignmentOperator()))
          continue;

      F.erase();
    }
    F.done();
  }

  // Suppress the protected check (C++ [class.protected]) for each of the
  // assignment operators we found. This strange dance is required when
  // we're assigning via a base classes's copy-assignment operator. To
  // ensure that we're getting the right base class subobject (without
  // ambiguities), we need to cast "this" to that subobject type; to
  // ensure that we don't go through the virtual call mechanism, we need
  // to qualify the operator= name with the base class (see below). However,
  // this means that if the base class has a protected copy assignment
  // operator, the protected member access check will fail. So, we
  // rewrite "protected" access to "public" access in this case, since we
  // know by construction that we're calling from a derived class.
  if (CopyingBaseSubobject) {
    for (LookupResult::iterator L = OpLookup.begin(), LEnd = OpLookup.end();
         L != LEnd; ++L) {
      if (L.getAccess() == AS_protected)
        L.setAccess(AS_public);
    }
  }

  // Create the nested-name-specifier that will be used to qualify the
  // reference to operator=; this is required to suppress the virtual
  // call mechanism.
  CXXScopeSpec SS;
  const Type *CanonicalT = S.Context.getCanonicalType(T.getTypePtr());
  SS.MakeTrivial(S.Context,
                 NestedNameSpecifier::Create(S.Context, nullptr, false,
                                             CanonicalT),
                 Loc);

  // Create the reference to operator=.
  ExprResult OpEqualRef
    = S.BuildMemberReferenceExpr(To.build(S, Loc), T, Loc, /*IsArrow=*/false,
                                 SS, /*TemplateKWLoc=*/SourceLocation(),
                                 /*FirstQualifierInScope=*/nullptr,
                                 OpLookup,
                                 /*TemplateArgs=*/nullptr, /*S*/nullptr,
                                 /*SuppressQualifierCheck=*/true);
  if (OpEqualRef.isInvalid())
    return StmtError();

  // Build the call to the assignment operator.

  Expr *FromInst = From.build(S, Loc);
  ExprResult Call = S.BuildCallToMemberFunction(/*Scope=*/nullptr,
                                                OpEqualRef.getAs<Expr>(),
                                                Loc, FromInst, Loc);
  if (Call.isInvalid())
    return StmtError();

  // If we built a call to a trivial 'operator=' while copying an array,
  // bail out. We'll replace the whole shebang with a memcpy.
  CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(Call.get());
  if (CE && CE->getMethodDecl()->isTrivial() && Depth)
    return StmtResult((Stmt*)nullptr);

  // Convert to an expression-statement, and clean up any produced
  // temporaries.
  return S.ActOnExprStmt(Call);
}

//     - if the subobject is of scalar type, the built-in assignment
//       operator is used.
const ConstantArrayType *ArrayTy = S.Context.getAsConstantArrayType(T);
if (!ArrayTy) {
  ExprResult Assignment = S.CreateBuiltinBinOp(
      Loc, BO_Assign, To.build(S, Loc), From.build(S, Loc));
  if (Assignment.isInvalid())
    return StmtError();
  return S.ActOnExprStmt(Assignment);
}

//     - if the subobject is an array, each element is assigned, in the
//       manner appropriate to the element type;

// Construct a loop over the array bounds, e.g.,
//
//   for (__SIZE_TYPE__ i0 = 0; i0 != array-size; ++i0)
//
// that will copy each of the array elements.
QualType SizeType = S.Context.getSizeType();

// Create the iteration variable.
IdentifierInfo *IterationVarName = nullptr;
{
  SmallString<8> Str;
  llvm::raw_svector_ostream OS(Str);
  OS << "__i" << Depth;
  IterationVarName = &S.Context.Idents.get(OS.str());
}
VarDecl *IterationVar = VarDecl::Create(S.Context, S.CurContext, Loc, Loc,
                                        IterationVarName, SizeType,
                          S.Context.getTrivialTypeSourceInfo(SizeType, Loc),
                                        SC_None);

// Initialize the iteration variable to zero.
llvm::APInt Zero(S.Context.getTypeSize(SizeType), 0);
IterationVar->setInit(IntegerLiteral::Create(S.Context, Zero, SizeType, Loc));

// Creates a reference to the iteration variable.
RefBuilder IterationVarRef(IterationVar, SizeType);
LvalueConvBuilder IterationVarRefRVal(IterationVarRef);

// Create the DeclStmt that holds the iteration variable.
Stmt *InitStmt = new (S.Context) DeclStmt(DeclGroupRef(IterationVar),Loc,Loc);

// Subscript the "from" and "to" expressions with the iteration variable.
SubscriptBuilder FromIndexCopy(From, IterationVarRefRVal);
MoveCastBuilder FromIndexMove(FromIndexCopy);
const ExprBuilder *FromIndex;
if (Copying)
  FromIndex = &FromIndexCopy;
else
  FromIndex = &FromIndexMove;

SubscriptBuilder ToIndex(To, IterationVarRefRVal);

// Build the copy/move for an individual element of the array.
StmtResult Copy =
  buildSingleCopyAssignRecursively(S, Loc, ArrayTy->getElementType(),
                                   ToIndex, *FromIndex, CopyingBaseSubobject,
                                   Copying, Depth + 1);
// Bail out if copying fails or if we determined that we should use memcpy.
if (Copy.isInvalid() || !Copy.get())
  return Copy;

// Create the comparison against the array bound.
llvm::APInt Upper
  = ArrayTy->getSize().zextOrTrunc(S.Context.getTypeSize(SizeType));
Expr *Comparison = BinaryOperator::Create(
    S.Context, IterationVarRefRVal.build(S, Loc),
    IntegerLiteral::Create(S.Context, Upper, SizeType, Loc), BO_NE,
    S.Context.BoolTy, VK_PRValue, OK_Ordinary, Loc,
    S.CurFPFeatureOverrides());

// Create the pre-increment of the iteration variable. We can determine
// whether the increment will overflow based on the value of the array
// bound.
Expr *Increment = UnaryOperator::Create(
    S.Context, IterationVarRef.build(S, Loc), UO_PreInc, SizeType, VK_LValue,
    OK_Ordinary, Loc, Upper.isMaxValue(), S.CurFPFeatureOverrides());

// Construct the loop that copies all elements of this array.
return S.ActOnForStmt(
    Loc, Loc, InitStmt,
    S.ActOnCondition(nullptr, Loc, Comparison, Sema::ConditionKind::Boolean),
    S.MakeFullDiscardedValueExpr(Increment), Loc, Copy.get());
14098}

14100static StmtResult
14101buildSingleCopyAssign(Sema &S, SourceLocation Loc, QualType T,
                    const ExprBuilder &To, const ExprBuilder &From,
                    bool CopyingBaseSubobject, bool Copying) {
// Maybe we should use a memcpy?
if (T->isArrayType() && !T.isConstQualified() && !T.isVolatileQualified() &&
    T.isTriviallyCopyableType(S.Context))
  return buildMemcpyForAssignmentOp(S, Loc, T, To, From);

StmtResult Result(buildSingleCopyAssignRecursively(S, Loc, T, To, From,
                                                   CopyingBaseSubobject,
                                                   Copying, 0));

// If we ended up picking a trivial assignment operator for an array of a
// non-trivially-copyable class type, just emit a memcpy.
if (!Result.isInvalid() && !Result.get())
  return buildMemcpyForAssignmentOp(S, Loc, T, To, From);

return Result;
14119}

14121CXXMethodDecl *Sema::DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl) {
// Note: The following rules are largely analoguous to the copy
// constructor rules. Note that virtual bases are not taken into account
// for determining the argument type of the operator. Note also that
// operators taking an object instead of a reference are allowed.
assert(ClassDecl->needsImplicitCopyAssignment())((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXCopyAssignment);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

QualType ArgType = Context.getTypeDeclType(ClassDecl);
LangAS AS = getDefaultCXXMethodAddrSpace();
if (AS != LangAS::Default)
  ArgType = Context.getAddrSpaceQualType(ArgType, AS);
QualType RetType = Context.getLValueReferenceType(ArgType);
bool Const = ClassDecl->implicitCopyAssignmentHasConstParam();
if (Const)
  ArgType = ArgType.withConst();

ArgType = Context.getLValueReferenceType(ArgType);

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXCopyAssignment,
                                                   Const);

//   An implicitly-declared copy assignment operator is an inline public
//   member of its class.
DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(OO_Equal);
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationNameInfo NameInfo(Name, ClassLoc);
CXXMethodDecl *CopyAssignment = CXXMethodDecl::Create(
    Context, ClassDecl, ClassLoc, NameInfo, QualType(),
    /*TInfo=*/nullptr, /*StorageClass=*/SC_None,
    /*isInline=*/true,
    Constexpr ? ConstexprSpecKind::Constexpr : ConstexprSpecKind::Unspecified,
    SourceLocation());
CopyAssignment->setAccess(AS_public);
CopyAssignment->setDefaulted();
CopyAssignment->setImplicit();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXCopyAssignment,
                                          CopyAssignment,
                                          /* ConstRHS */ Const,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(CopyAssignment, RetType, ArgType);

// Add the parameter to the operator.
ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyAssignment,
                                             ClassLoc, ClassLoc,
                                             /*Id=*/nullptr, ArgType,
                                             /*TInfo=*/nullptr, SC_None,
                                             nullptr);
CopyAssignment->setParams(FromParam);

CopyAssignment->setTrivial(
  ClassDecl->needsOverloadResolutionForCopyAssignment()
    ? SpecialMemberIsTrivial(CopyAssignment, CXXCopyAssignment)
    : ClassDecl->hasTrivialCopyAssignment());

// Note that we have added this copy-assignment operator.
++getASTContext().NumImplicitCopyAssignmentOperatorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, CopyAssignment);

if (ShouldDeleteSpecialMember(CopyAssignment, CXXCopyAssignment)) {
  ClassDecl->setImplicitCopyAssignmentIsDeleted();
  SetDeclDeleted(CopyAssignment, ClassLoc);
}

if (S)
  PushOnScopeChains(CopyAssignment, S, false);
ClassDecl->addDecl(CopyAssignment);

return CopyAssignment;
14200}

14202/// Diagnose an implicit copy operation for a class which is odr-used, but
14203/// which is deprecated because the class has a user-declared copy constructor,
14204/// copy assignment operator, or destructor.
14205static void diagnoseDeprecatedCopyOperation(Sema &S, CXXMethodDecl *CopyOp) {
assert(CopyOp->isImplicit())((void)0);

CXXRecordDecl *RD = CopyOp->getParent();
CXXMethodDecl *UserDeclaredOperation = nullptr;

// In Microsoft mode, assignment operations don't affect constructors and
// vice versa.
if (RD->hasUserDeclaredDestructor()) {
  UserDeclaredOperation = RD->getDestructor();
} else if (!isa<CXXConstructorDecl>(CopyOp) &&
           RD->hasUserDeclaredCopyConstructor() &&
           !S.getLangOpts().MSVCCompat) {
  // Find any user-declared copy constructor.
  for (auto *I : RD->ctors()) {
    if (I->isCopyConstructor()) {
      UserDeclaredOperation = I;
      break;
    }
  }
  assert(UserDeclaredOperation)((void)0);
} else if (isa<CXXConstructorDecl>(CopyOp) &&
           RD->hasUserDeclaredCopyAssignment() &&
           !S.getLangOpts().MSVCCompat) {
  // Find any user-declared move assignment operator.
  for (auto *I : RD->methods()) {
    if (I->isCopyAssignmentOperator()) {
      UserDeclaredOperation = I;
      break;
    }
  }
  assert(UserDeclaredOperation)((void)0);
}

if (UserDeclaredOperation) {
  bool UDOIsUserProvided = UserDeclaredOperation->isUserProvided();
  bool UDOIsDestructor = isa<CXXDestructorDecl>(UserDeclaredOperation);
  bool IsCopyAssignment = !isa<CXXConstructorDecl>(CopyOp);
  unsigned DiagID =
      (UDOIsUserProvided && UDOIsDestructor)
          ? diag::warn_deprecated_copy_with_user_provided_dtor
      : (UDOIsUserProvided && !UDOIsDestructor)
          ? diag::warn_deprecated_copy_with_user_provided_copy
      : (!UDOIsUserProvided && UDOIsDestructor)
          ? diag::warn_deprecated_copy_with_dtor
          : diag::warn_deprecated_copy;
  S.Diag(UserDeclaredOperation->getLocation(), DiagID)
      << RD << IsCopyAssignment;
}
14254}

14256void Sema::DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                      CXXMethodDecl *CopyAssignOperator) {
assert((CopyAssignOperator->isDefaulted() &&((void)0)
        CopyAssignOperator->isOverloadedOperator() &&((void)0)
        CopyAssignOperator->getOverloadedOperator() == OO_Equal &&((void)0)
        !CopyAssignOperator->doesThisDeclarationHaveABody() &&((void)0)
        !CopyAssignOperator->isDeleted()) &&((void)0)
       "DefineImplicitCopyAssignment called for wrong function")((void)0);
if (CopyAssignOperator->willHaveBody() || CopyAssignOperator->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = CopyAssignOperator->getParent();
if (ClassDecl->isInvalidDecl()) {
  CopyAssignOperator->setInvalidDecl();
  return;
}

SynthesizedFunctionScope Scope(*this, CopyAssignOperator);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     CopyAssignOperator->getType()->castAs<FunctionProtoType>());

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

// C++11 [class.copy]p18:
//   The [definition of an implicitly declared copy assignment operator] is
//   deprecated if the class has a user-declared copy constructor or a
//   user-declared destructor.
if (getLangOpts().CPlusPlus11 && CopyAssignOperator->isImplicit())
  diagnoseDeprecatedCopyOperation(*this, CopyAssignOperator);

// C++0x [class.copy]p30:
//   The implicitly-defined or explicitly-defaulted copy assignment operator
//   for a non-union class X performs memberwise copy assignment of its
//   subobjects. The direct base classes of X are assigned first, in the
//   order of their declaration in the base-specifier-list, and then the
//   immediate non-static data members of X are assigned, in the order in
//   which they were declared in the class definition.

// The statements that form the synthesized function body.
SmallVector<Stmt*, 8> Statements;

// The parameter for the "other" object, which we are copying from.
ParmVarDecl *Other = CopyAssignOperator->getParamDecl(0);
Qualifiers OtherQuals = Other->getType().getQualifiers();
QualType OtherRefType = Other->getType();
if (const LValueReferenceType *OtherRef
                              = OtherRefType->getAs<LValueReferenceType>()) {
  OtherRefType = OtherRef->getPointeeType();
  OtherQuals = OtherRefType.getQualifiers();
}

// Our location for everything implicitly-generated.
SourceLocation Loc = CopyAssignOperator->getEndLoc().isValid()
                         ? CopyAssignOperator->getEndLoc()
                         : CopyAssignOperator->getLocation();

// Builds a DeclRefExpr for the "other" object.
RefBuilder OtherRef(Other, OtherRefType);

// Builds the "this" pointer.
ThisBuilder This;

// Assign base classes.
bool Invalid = false;
for (auto &Base : ClassDecl->bases()) {
  // Form the assignment:
  //   static_cast<Base*>(this)->Base::operator=(static_cast<Base&>(other));
  QualType BaseType = Base.getType().getUnqualifiedType();
  if (!BaseType->isRecordType()) {
    Invalid = true;
    continue;
  }

  CXXCastPath BasePath;
  BasePath.push_back(&Base);

  // Construct the "from" expression, which is an implicit cast to the
  // appropriately-qualified base type.
  CastBuilder From(OtherRef, Context.getQualifiedType(BaseType, OtherQuals),
                   VK_LValue, BasePath);

  // Dereference "this".
  DerefBuilder DerefThis(This);
  CastBuilder To(DerefThis,
                 Context.getQualifiedType(
                     BaseType, CopyAssignOperator->getMethodQualifiers()),
                 VK_LValue, BasePath);

  // Build the copy.
  StmtResult Copy = buildSingleCopyAssign(*this, Loc, BaseType,
                                          To, From,
                                          /*CopyingBaseSubobject=*/true,
                                          /*Copying=*/true);
  if (Copy.isInvalid()) {
    CopyAssignOperator->setInvalidDecl();
    return;
  }

  // Success! Record the copy.
  Statements.push_back(Copy.getAs<Expr>());
}

// Assign non-static members.
for (auto *Field : ClassDecl->fields()) {
  // FIXME: We should form some kind of AST representation for the implied
  // memcpy in a union copy operation.
  if (Field->isUnnamedBitfield() || Field->getParent()->isUnion())
    continue;

  if (Field->isInvalidDecl()) {
    Invalid = true;
    continue;
  }

  // Check for members of reference type; we can't copy those.
  if (Field->getType()->isReferenceType()) {
    Diag(ClassDecl->getLocation(), diag::err_uninitialized_member_for_assign)
      << Context.getTagDeclType(ClassDecl) << 0 << Field->getDeclName();
    Diag(Field->getLocation(), diag::note_declared_at);
    Invalid = true;
    continue;
  }

  // Check for members of const-qualified, non-class type.
  QualType BaseType = Context.getBaseElementType(Field->getType());
  if (!BaseType->getAs<RecordType>() && BaseType.isConstQualified()) {
    Diag(ClassDecl->getLocation(), diag::err_uninitialized_member_for_assign)
      << Context.getTagDeclType(ClassDecl) << 1 << Field->getDeclName();
    Diag(Field->getLocation(), diag::note_declared_at);
    Invalid = true;
    continue;
  }

  // Suppress assigning zero-width bitfields.
  if (Field->isZeroLengthBitField(Context))
    continue;

  QualType FieldType = Field->getType().getNonReferenceType();
  if (FieldType->isIncompleteArrayType()) {
    assert(ClassDecl->hasFlexibleArrayMember() &&((void)0)
           "Incomplete array type is not valid")((void)0);
    continue;
  }

  // Build references to the field in the object we're copying from and to.
  CXXScopeSpec SS; // Intentionally empty
  LookupResult MemberLookup(*this, Field->getDeclName(), Loc,
                            LookupMemberName);
  MemberLookup.addDecl(Field);
  MemberLookup.resolveKind();

  MemberBuilder From(OtherRef, OtherRefType, /*IsArrow=*/false, MemberLookup);

  MemberBuilder To(This, getCurrentThisType(), /*IsArrow=*/true, MemberLookup);

  // Build the copy of this field.
  StmtResult Copy = buildSingleCopyAssign(*this, Loc, FieldType,
                                          To, From,
                                          /*CopyingBaseSubobject=*/false,
                                          /*Copying=*/true);
  if (Copy.isInvalid()) {
    CopyAssignOperator->setInvalidDecl();
    return;
  }

  // Success! Record the copy.
  Statements.push_back(Copy.getAs<Stmt>());
}

if (!Invalid) {
  // Add a "return *this;"
  ExprResult ThisObj = CreateBuiltinUnaryOp(Loc, UO_Deref, This.build(*this, Loc));

  StmtResult Return = BuildReturnStmt(Loc, ThisObj.get());
  if (Return.isInvalid())
    Invalid = true;
  else
    Statements.push_back(Return.getAs<Stmt>());
}

if (Invalid) {
  CopyAssignOperator->setInvalidDecl();
  return;
}

StmtResult Body;
{
  CompoundScopeRAII CompoundScope(*this);
  Body = ActOnCompoundStmt(Loc, Loc, Statements,
                           /*isStmtExpr=*/false);
  assert(!Body.isInvalid() && "Compound statement creation cannot fail")((void)0);
}
CopyAssignOperator->setBody(Body.getAs<Stmt>());
CopyAssignOperator->markUsed(Context);

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(CopyAssignOperator);
}
14458}

14460CXXMethodDecl *Sema::DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl) {
assert(ClassDecl->needsImplicitMoveAssignment())((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXMoveAssignment);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

// Note: The following rules are largely analoguous to the move
// constructor rules.

QualType ArgType = Context.getTypeDeclType(ClassDecl);
LangAS AS = getDefaultCXXMethodAddrSpace();
if (AS != LangAS::Default)
  ArgType = Context.getAddrSpaceQualType(ArgType, AS);
QualType RetType = Context.getLValueReferenceType(ArgType);
ArgType = Context.getRValueReferenceType(ArgType);

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXMoveAssignment,
                                                   false);

//   An implicitly-declared move assignment operator is an inline public
//   member of its class.
DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(OO_Equal);
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationNameInfo NameInfo(Name, ClassLoc);
CXXMethodDecl *MoveAssignment = CXXMethodDecl::Create(
    Context, ClassDecl, ClassLoc, NameInfo, QualType(),
    /*TInfo=*/nullptr, /*StorageClass=*/SC_None,
    /*isInline=*/true,
    Constexpr ? ConstexprSpecKind::Constexpr : ConstexprSpecKind::Unspecified,
    SourceLocation());
MoveAssignment->setAccess(AS_public);
MoveAssignment->setDefaulted();
MoveAssignment->setImplicit();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXMoveAssignment,
                                          MoveAssignment,
                                          /* ConstRHS */ false,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(MoveAssignment, RetType, ArgType);

// Add the parameter to the operator.
ParmVarDecl *FromParam = ParmVarDecl::Create(Context, MoveAssignment,
                                             ClassLoc, ClassLoc,
                                             /*Id=*/nullptr, ArgType,
                                             /*TInfo=*/nullptr, SC_None,
                                             nullptr);
MoveAssignment->setParams(FromParam);

MoveAssignment->setTrivial(
  ClassDecl->needsOverloadResolutionForMoveAssignment()
    ? SpecialMemberIsTrivial(MoveAssignment, CXXMoveAssignment)
    : ClassDecl->hasTrivialMoveAssignment());

// Note that we have added this copy-assignment operator.
++getASTContext().NumImplicitMoveAssignmentOperatorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, MoveAssignment);

if (ShouldDeleteSpecialMember(MoveAssignment, CXXMoveAssignment)) {
  ClassDecl->setImplicitMoveAssignmentIsDeleted();
  SetDeclDeleted(MoveAssignment, ClassLoc);
}

if (S)
  PushOnScopeChains(MoveAssignment, S, false);
ClassDecl->addDecl(MoveAssignment);

return MoveAssignment;
14534}

14536/// Check if we're implicitly defining a move assignment operator for a class
14537/// with virtual bases. Such a move assignment might move-assign the virtual
14538/// base multiple times.
14539static void checkMoveAssignmentForRepeatedMove(Sema &S, CXXRecordDecl *Class,
                                             SourceLocation CurrentLocation) {
assert(!Class->isDependentContext() && "should not define dependent move")((void)0);

// Only a virtual base could get implicitly move-assigned multiple times.
// Only a non-trivial move assignment can observe this. We only want to
// diagnose if we implicitly define an assignment operator that assigns
// two base classes, both of which move-assign the same virtual base.
if (Class->getNumVBases() == 0 || Class->hasTrivialMoveAssignment() ||
    Class->getNumBases() < 2)
  return;

llvm::SmallVector<CXXBaseSpecifier *, 16> Worklist;
typedef llvm::DenseMap<CXXRecordDecl*, CXXBaseSpecifier*> VBaseMap;
VBaseMap VBases;

for (auto &BI : Class->bases()) {
  Worklist.push_back(&BI);
  while (!Worklist.empty()) {
    CXXBaseSpecifier *BaseSpec = Worklist.pop_back_val();
    CXXRecordDecl *Base = BaseSpec->getType()->getAsCXXRecordDecl();

    // If the base has no non-trivial move assignment operators,
    // we don't care about moves from it.
    if (!Base->hasNonTrivialMoveAssignment())
      continue;

    // If there's nothing virtual here, skip it.
    if (!BaseSpec->isVirtual() && !Base->getNumVBases())
      continue;

    // If we're not actually going to call a move assignment for this base,
    // or the selected move assignment is trivial, skip it.
    Sema::SpecialMemberOverloadResult SMOR =
      S.LookupSpecialMember(Base, Sema::CXXMoveAssignment,
                            /*ConstArg*/false, /*VolatileArg*/false,
                            /*RValueThis*/true, /*ConstThis*/false,
                            /*VolatileThis*/false);
    if (!SMOR.getMethod() || SMOR.getMethod()->isTrivial() ||
        !SMOR.getMethod()->isMoveAssignmentOperator())
      continue;

    if (BaseSpec->isVirtual()) {
      // We're going to move-assign this virtual base, and its move
      // assignment operator is not trivial. If this can happen for
      // multiple distinct direct bases of Class, diagnose it. (If it
      // only happens in one base, we'll diagnose it when synthesizing
      // that base class's move assignment operator.)
      CXXBaseSpecifier *&Existing =
          VBases.insert(std::make_pair(Base->getCanonicalDecl(), &BI))
              .first->second;
      if (Existing && Existing != &BI) {
        S.Diag(CurrentLocation, diag::warn_vbase_moved_multiple_times)
          << Class << Base;
        S.Diag(Existing->getBeginLoc(), diag::note_vbase_moved_here)
            << (Base->getCanonicalDecl() ==
                Existing->getType()->getAsCXXRecordDecl()->getCanonicalDecl())
            << Base << Existing->getType() << Existing->getSourceRange();
        S.Diag(BI.getBeginLoc(), diag::note_vbase_moved_here)
            << (Base->getCanonicalDecl() ==
                BI.getType()->getAsCXXRecordDecl()->getCanonicalDecl())
            << Base << BI.getType() << BaseSpec->getSourceRange();

        // Only diagnose each vbase once.
        Existing = nullptr;
      }
    } else {
      // Only walk over bases that have defaulted move assignment operators.
      // We assume that any user-provided move assignment operator handles
      // the multiple-moves-of-vbase case itself somehow.
      if (!SMOR.getMethod()->isDefaulted())
        continue;

      // We're going to move the base classes of Base. Add them to the list.
      for (auto &BI : Base->bases())
        Worklist.push_back(&BI);
    }
  }
}
14618}

14620void Sema::DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
                                      CXXMethodDecl *MoveAssignOperator) {
assert((MoveAssignOperator->isDefaulted() &&((void)0)
        MoveAssignOperator->isOverloadedOperator() &&((void)0)
        MoveAssignOperator->getOverloadedOperator() == OO_Equal &&((void)0)
        !MoveAssignOperator->doesThisDeclarationHaveABody() &&((void)0)
        !MoveAssignOperator->isDeleted()) &&((void)0)
       "DefineImplicitMoveAssignment called for wrong function")((void)0);
if (MoveAssignOperator->willHaveBody() || MoveAssignOperator->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = MoveAssignOperator->getParent();
if (ClassDecl->isInvalidDecl()) {
  MoveAssignOperator->setInvalidDecl();
  return;
}

// C++0x [class.copy]p28:
//   The implicitly-defined or move assignment operator for a non-union class
//   X performs memberwise move assignment of its subobjects. The direct base
//   classes of X are assigned first, in the order of their declaration in the
//   base-specifier-list, and then the immediate non-static data members of X
//   are assigned, in the order in which they were declared in the class
//   definition.

// Issue a warning if our implicit move assignment operator will move
// from a virtual base more than once.
checkMoveAssignmentForRepeatedMove(*this, ClassDecl, CurrentLocation);

SynthesizedFunctionScope Scope(*this, MoveAssignOperator);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     MoveAssignOperator->getType()->castAs<FunctionProtoType>());

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

// The statements that form the synthesized function body.
SmallVector<Stmt*, 8> Statements;

// The parameter for the "other" object, which we are move from.
ParmVarDecl *Other = MoveAssignOperator->getParamDecl(0);
QualType OtherRefType =
    Other->getType()->castAs<RValueReferenceType>()->getPointeeType();

// Our location for everything implicitly-generated.
SourceLocation Loc = MoveAssignOperator->getEndLoc().isValid()
                         ? MoveAssignOperator->getEndLoc()
                         : MoveAssignOperator->getLocation();

// Builds a reference to the "other" object.
RefBuilder OtherRef(Other, OtherRefType);
// Cast to rvalue.
MoveCastBuilder MoveOther(OtherRef);

// Builds the "this" pointer.
ThisBuilder This;

// Assign base classes.
bool Invalid = false;
for (auto &Base : ClassDecl->bases()) {
  // C++11 [class.copy]p28:
  //   It is unspecified whether subobjects representing virtual base classes
  //   are assigned more than once by the implicitly-defined copy assignment
  //   operator.
  // FIXME: Do not assign to a vbase that will be assigned by some other base
  // class. For a move-assignment, this can result in the vbase being moved
  // multiple times.

  // Form the assignment:
  //   static_cast<Base*>(this)->Base::operator=(static_cast<Base&&>(other));
  QualType BaseType = Base.getType().getUnqualifiedType();
  if (!BaseType->isRecordType()) {
    Invalid = true;
    continue;
  }

  CXXCastPath BasePath;
  BasePath.push_back(&Base);

  // Construct the "from" expression, which is an implicit cast to the
  // appropriately-qualified base type.
  CastBuilder From(OtherRef, BaseType, VK_XValue, BasePath);

  // Dereference "this".
  DerefBuilder DerefThis(This);

  // Implicitly cast "this" to the appropriately-qualified base type.
  CastBuilder To(DerefThis,
                 Context.getQualifiedType(
                     BaseType, MoveAssignOperator->getMethodQualifiers()),
                 VK_LValue, BasePath);

  // Build the move.
  StmtResult Move = buildSingleCopyAssign(*this, Loc, BaseType,
                                          To, From,
                                          /*CopyingBaseSubobject=*/true,
                                          /*Copying=*/false);
  if (Move.isInvalid()) {
    MoveAssignOperator->setInvalidDecl();
    return;
  }

  // Success! Record the move.
  Statements.push_back(Move.getAs<Expr>());
}

// Assign non-static members.
for (auto *Field : ClassDecl->fields()) {
  // FIXME: We should form some kind of AST representation for the implied
  // memcpy in a union copy operation.
  if (Field->isUnnamedBitfield() || Field->getParent()->isUnion())
    continue;

  if (Field->isInvalidDecl()) {
    Invalid = true;
    continue;
  }

  // Check for members of reference type; we can't move those.
  if (Field->getType()->isReferenceType()) {
    Diag(ClassDecl->getLocation(), diag::err_uninitialized_member_for_assign)
      << Context.getTagDeclType(ClassDecl) << 0 << Field->getDeclName();
    Diag(Field->getLocation(), diag::note_declared_at);
    Invalid = true;
    continue;
  }

  // Check for members of const-qualified, non-class type.
  QualType BaseType = Context.getBaseElementType(Field->getType());
  if (!BaseType->getAs<RecordType>() && BaseType.isConstQualified()) {
    Diag(ClassDecl->getLocation(), diag::err_uninitialized_member_for_assign)
      << Context.getTagDeclType(ClassDecl) << 1 << Field->getDeclName();
    Diag(Field->getLocation(), diag::note_declared_at);
    Invalid = true;
    continue;
  }

  // Suppress assigning zero-width bitfields.
  if (Field->isZeroLengthBitField(Context))
    continue;

  QualType FieldType = Field->getType().getNonReferenceType();
  if (FieldType->isIncompleteArrayType()) {
    assert(ClassDecl->hasFlexibleArrayMember() &&((void)0)
           "Incomplete array type is not valid")((void)0);
    continue;
  }

  // Build references to the field in the object we're copying from and to.
  LookupResult MemberLookup(*this, Field->getDeclName(), Loc,
                            LookupMemberName);
  MemberLookup.addDecl(Field);
  MemberLookup.resolveKind();
  MemberBuilder From(MoveOther, OtherRefType,
                     /*IsArrow=*/false, MemberLookup);
  MemberBuilder To(This, getCurrentThisType(),
                   /*IsArrow=*/true, MemberLookup);

  assert(!From.build(*this, Loc)->isLValue() && // could be xvalue or prvalue((void)0)
      "Member reference with rvalue base must be rvalue except for reference "((void)0)
      "members, which aren't allowed for move assignment.")((void)0);

  // Build the move of this field.
  StmtResult Move = buildSingleCopyAssign(*this, Loc, FieldType,
                                          To, From,
                                          /*CopyingBaseSubobject=*/false,
                                          /*Copying=*/false);
  if (Move.isInvalid()) {
    MoveAssignOperator->setInvalidDecl();
    return;
  }

  // Success! Record the copy.
  Statements.push_back(Move.getAs<Stmt>());
}

if (!Invalid) {
  // Add a "return *this;"
  ExprResult ThisObj =
      CreateBuiltinUnaryOp(Loc, UO_Deref, This.build(*this, Loc));

  StmtResult Return = BuildReturnStmt(Loc, ThisObj.get());
  if (Return.isInvalid())
    Invalid = true;
  else
    Statements.push_back(Return.getAs<Stmt>());
}

if (Invalid) {
  MoveAssignOperator->setInvalidDecl();
  return;
}

StmtResult Body;
{
  CompoundScopeRAII CompoundScope(*this);
  Body = ActOnCompoundStmt(Loc, Loc, Statements,
                           /*isStmtExpr=*/false);
  assert(!Body.isInvalid() && "Compound statement creation cannot fail")((void)0);
}
MoveAssignOperator->setBody(Body.getAs<Stmt>());
MoveAssignOperator->markUsed(Context);

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(MoveAssignOperator);
}
14829}

14831CXXConstructorDecl *Sema::DeclareImplicitCopyConstructor(
                                                  CXXRecordDecl *ClassDecl) {
// C++ [class.copy]p4:
//   If the class definition does not explicitly declare a copy
//   constructor, one is declared implicitly.
assert(ClassDecl->needsImplicitCopyConstructor())((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXCopyConstructor);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

QualType ClassType = Context.getTypeDeclType(ClassDecl);
QualType ArgType = ClassType;
bool Const = ClassDecl->implicitCopyConstructorHasConstParam();
if (Const)
  ArgType = ArgType.withConst();

LangAS AS = getDefaultCXXMethodAddrSpace();
if (AS != LangAS::Default)
  ArgType = Context.getAddrSpaceQualType(ArgType, AS);

ArgType = Context.getLValueReferenceType(ArgType);

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXCopyConstructor,
                                                   Const);

DeclarationName Name
  = Context.DeclarationNames.getCXXConstructorName(
                                         Context.getCanonicalType(ClassType));
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationNameInfo NameInfo(Name, ClassLoc);

//   An implicitly-declared copy constructor is an inline public
//   member of its class.
CXXConstructorDecl *CopyConstructor = CXXConstructorDecl::Create(
    Context, ClassDecl, ClassLoc, NameInfo, QualType(), /*TInfo=*/nullptr,
    ExplicitSpecifier(),
    /*isInline=*/true,
    /*isImplicitlyDeclared=*/true,
    Constexpr ? ConstexprSpecKind::Constexpr
              : ConstexprSpecKind::Unspecified);
CopyConstructor->setAccess(AS_public);
CopyConstructor->setDefaulted();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXCopyConstructor,
                                          CopyConstructor,
                                          /* ConstRHS */ Const,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(CopyConstructor, Context.VoidTy, ArgType);

// During template instantiation of special member functions we need a
// reliable TypeSourceInfo for the parameter types in order to allow functions
// to be substituted.
TypeSourceInfo *TSI = nullptr;
if (inTemplateInstantiation() && ClassDecl->isLambda())
  TSI = Context.getTrivialTypeSourceInfo(ArgType);

// Add the parameter to the constructor.
ParmVarDecl *FromParam =
    ParmVarDecl::Create(Context, CopyConstructor, ClassLoc, ClassLoc,
                        /*IdentifierInfo=*/nullptr, ArgType,
                        /*TInfo=*/TSI, SC_None, nullptr);
CopyConstructor->setParams(FromParam);

CopyConstructor->setTrivial(
    ClassDecl->needsOverloadResolutionForCopyConstructor()
        ? SpecialMemberIsTrivial(CopyConstructor, CXXCopyConstructor)
        : ClassDecl->hasTrivialCopyConstructor());

CopyConstructor->setTrivialForCall(
    ClassDecl->hasAttr<TrivialABIAttr>() ||
    (ClassDecl->needsOverloadResolutionForCopyConstructor()
         ? SpecialMemberIsTrivial(CopyConstructor, CXXCopyConstructor,
           TAH_ConsiderTrivialABI)
         : ClassDecl->hasTrivialCopyConstructorForCall()));

// Note that we have declared this constructor.
++getASTContext().NumImplicitCopyConstructorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, CopyConstructor);

if (ShouldDeleteSpecialMember(CopyConstructor, CXXCopyConstructor)) {
  ClassDecl->setImplicitCopyConstructorIsDeleted();
  SetDeclDeleted(CopyConstructor, ClassLoc);
}

if (S)
  PushOnScopeChains(CopyConstructor, S, false);
ClassDecl->addDecl(CopyConstructor);

return CopyConstructor;
14927}

14929void Sema::DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                       CXXConstructorDecl *CopyConstructor) {
assert((CopyConstructor->isDefaulted() &&((void)0)
        CopyConstructor->isCopyConstructor() &&((void)0)
        !CopyConstructor->doesThisDeclarationHaveABody() &&((void)0)
        !CopyConstructor->isDeleted()) &&((void)0)
       "DefineImplicitCopyConstructor - call it for implicit copy ctor")((void)0);
if (CopyConstructor->willHaveBody() || CopyConstructor->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = CopyConstructor->getParent();
assert(ClassDecl && "DefineImplicitCopyConstructor - invalid constructor")((void)0);

SynthesizedFunctionScope Scope(*this, CopyConstructor);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     CopyConstructor->getType()->castAs<FunctionProtoType>());
MarkVTableUsed(CurrentLocation, ClassDecl);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

// C++11 [class.copy]p7:
//   The [definition of an implicitly declared copy constructor] is
//   deprecated if the class has a user-declared copy assignment operator
//   or a user-declared destructor.
if (getLangOpts().CPlusPlus11 && CopyConstructor->isImplicit())
  diagnoseDeprecatedCopyOperation(*this, CopyConstructor);

if (SetCtorInitializers(CopyConstructor, /*AnyErrors=*/false)) {
  CopyConstructor->setInvalidDecl();
}  else {
  SourceLocation Loc = CopyConstructor->getEndLoc().isValid()
                           ? CopyConstructor->getEndLoc()
                           : CopyConstructor->getLocation();
  Sema::CompoundScopeRAII CompoundScope(*this);
  CopyConstructor->setBody(
      ActOnCompoundStmt(Loc, Loc, None, /*isStmtExpr=*/false).getAs<Stmt>());
  CopyConstructor->markUsed(Context);
}

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(CopyConstructor);
}
14975}

14977CXXConstructorDecl *Sema::DeclareImplicitMoveConstructor(
                                                  CXXRecordDecl *ClassDecl) {
assert(ClassDecl->needsImplicitMoveConstructor())((void)0);

DeclaringSpecialMember DSM(*this, ClassDecl, CXXMoveConstructor);
if (DSM.isAlreadyBeingDeclared())
  return nullptr;

QualType ClassType = Context.getTypeDeclType(ClassDecl);

QualType ArgType = ClassType;
LangAS AS = getDefaultCXXMethodAddrSpace();
if (AS != LangAS::Default)
  ArgType = Context.getAddrSpaceQualType(ClassType, AS);
ArgType = Context.getRValueReferenceType(ArgType);

bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, ClassDecl,
                                                   CXXMoveConstructor,
                                                   false);

DeclarationName Name
  = Context.DeclarationNames.getCXXConstructorName(
                                         Context.getCanonicalType(ClassType));
SourceLocation ClassLoc = ClassDecl->getLocation();
DeclarationNameInfo NameInfo(Name, ClassLoc);

// C++11 [class.copy]p11:
//   An implicitly-declared copy/move constructor is an inline public
//   member of its class.
CXXConstructorDecl *MoveConstructor = CXXConstructorDecl::Create(
    Context, ClassDecl, ClassLoc, NameInfo, QualType(), /*TInfo=*/nullptr,
    ExplicitSpecifier(),
    /*isInline=*/true,
    /*isImplicitlyDeclared=*/true,
    Constexpr ? ConstexprSpecKind::Constexpr
              : ConstexprSpecKind::Unspecified);
MoveConstructor->setAccess(AS_public);
MoveConstructor->setDefaulted();

if (getLangOpts().CUDA) {
  inferCUDATargetForImplicitSpecialMember(ClassDecl, CXXMoveConstructor,
                                          MoveConstructor,
                                          /* ConstRHS */ false,
                                          /* Diagnose */ false);
}

setupImplicitSpecialMemberType(MoveConstructor, Context.VoidTy, ArgType);

// Add the parameter to the constructor.
ParmVarDecl *FromParam = ParmVarDecl::Create(Context, MoveConstructor,
                                             ClassLoc, ClassLoc,
                                             /*IdentifierInfo=*/nullptr,
                                             ArgType, /*TInfo=*/nullptr,
                                             SC_None, nullptr);
MoveConstructor->setParams(FromParam);

MoveConstructor->setTrivial(
    ClassDecl->needsOverloadResolutionForMoveConstructor()
        ? SpecialMemberIsTrivial(MoveConstructor, CXXMoveConstructor)
        : ClassDecl->hasTrivialMoveConstructor());

MoveConstructor->setTrivialForCall(
    ClassDecl->hasAttr<TrivialABIAttr>() ||
    (ClassDecl->needsOverloadResolutionForMoveConstructor()
         ? SpecialMemberIsTrivial(MoveConstructor, CXXMoveConstructor,
                                  TAH_ConsiderTrivialABI)
         : ClassDecl->hasTrivialMoveConstructorForCall()));

// Note that we have declared this constructor.
++getASTContext().NumImplicitMoveConstructorsDeclared;

Scope *S = getScopeForContext(ClassDecl);
CheckImplicitSpecialMemberDeclaration(S, MoveConstructor);

if (ShouldDeleteSpecialMember(MoveConstructor, CXXMoveConstructor)) {
  ClassDecl->setImplicitMoveConstructorIsDeleted();
  SetDeclDeleted(MoveConstructor, ClassLoc);
}

if (S)
  PushOnScopeChains(MoveConstructor, S, false);
ClassDecl->addDecl(MoveConstructor);

return MoveConstructor;
15061}

15063void Sema::DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
                                       CXXConstructorDecl *MoveConstructor) {
assert((MoveConstructor->isDefaulted() &&((void)0)
        MoveConstructor->isMoveConstructor() &&((void)0)
        !MoveConstructor->doesThisDeclarationHaveABody() &&((void)0)
        !MoveConstructor->isDeleted()) &&((void)0)
       "DefineImplicitMoveConstructor - call it for implicit move ctor")((void)0);
if (MoveConstructor->willHaveBody() || MoveConstructor->isInvalidDecl())
  return;

CXXRecordDecl *ClassDecl = MoveConstructor->getParent();
assert(ClassDecl && "DefineImplicitMoveConstructor - invalid constructor")((void)0);

SynthesizedFunctionScope Scope(*this, MoveConstructor);

// The exception specification is needed because we are defining the
// function.
ResolveExceptionSpec(CurrentLocation,
                     MoveConstructor->getType()->castAs<FunctionProtoType>());
MarkVTableUsed(CurrentLocation, ClassDecl);

// Add a context note for diagnostics produced after this point.
Scope.addContextNote(CurrentLocation);

if (SetCtorInitializers(MoveConstructor, /*AnyErrors=*/false)) {
  MoveConstructor->setInvalidDecl();
} else {
  SourceLocation Loc = MoveConstructor->getEndLoc().isValid()
                           ? MoveConstructor->getEndLoc()
                           : MoveConstructor->getLocation();
  Sema::CompoundScopeRAII CompoundScope(*this);
  MoveConstructor->setBody(ActOnCompoundStmt(
      Loc, Loc, None, /*isStmtExpr=*/ false).getAs<Stmt>());
  MoveConstructor->markUsed(Context);
}

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(MoveConstructor);
}
15102}

15104bool Sema::isImplicitlyDeleted(FunctionDecl *FD) {
return FD->isDeleted() && FD->isDefaulted() && isa<CXXMethodDecl>(FD);
15106}

15108void Sema::DefineImplicitLambdaToFunctionPointerConversion(
                          SourceLocation CurrentLocation,
                          CXXConversionDecl *Conv) {
SynthesizedFunctionScope Scope(*this, Conv);
assert(!Conv->getReturnType()->isUndeducedType())((void)0);

QualType ConvRT = Conv->getType()->castAs<FunctionType>()->getReturnType();
CallingConv CC =
    ConvRT->getPointeeType()->castAs<FunctionType>()->getCallConv();

CXXRecordDecl *Lambda = Conv->getParent();
FunctionDecl *CallOp = Lambda->getLambdaCallOperator();
FunctionDecl *Invoker = Lambda->getLambdaStaticInvoker(CC);

if (auto *TemplateArgs = Conv->getTemplateSpecializationArgs()) {
  CallOp = InstantiateFunctionDeclaration(
      CallOp->getDescribedFunctionTemplate(), TemplateArgs, CurrentLocation);
  if (!CallOp)
    return;

  Invoker = InstantiateFunctionDeclaration(
      Invoker->getDescribedFunctionTemplate(), TemplateArgs, CurrentLocation);
  if (!Invoker)
    return;
}

if (CallOp->isInvalidDecl())
  return;

// Mark the call operator referenced (and add to pending instantiations
// if necessary).
// For both the conversion and static-invoker template specializations
// we construct their body's in this function, so no need to add them
// to the PendingInstantiations.
MarkFunctionReferenced(CurrentLocation, CallOp);

// Fill in the __invoke function with a dummy implementation. IR generation
// will fill in the actual details. Update its type in case it contained
// an 'auto'.
Invoker->markUsed(Context);
Invoker->setReferenced();
Invoker->setType(Conv->getReturnType()->getPointeeType());
Invoker->setBody(new (Context) CompoundStmt(Conv->getLocation()));

// Construct the body of the conversion function { return __invoke; }.
Expr *FunctionRef = BuildDeclRefExpr(Invoker, Invoker->getType(),
                                     VK_LValue, Conv->getLocation());
assert(FunctionRef && "Can't refer to __invoke function?")((void)0);
Stmt *Return = BuildReturnStmt(Conv->getLocation(), FunctionRef).get();
Conv->setBody(CompoundStmt::Create(Context, Return, Conv->getLocation(),
                                   Conv->getLocation()));
Conv->markUsed(Context);
Conv->setReferenced();

if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(Conv);
  L->CompletedImplicitDefinition(Invoker);
}
15166}



15170void Sema::DefineImplicitLambdaToBlockPointerConversion(
     SourceLocation CurrentLocation,
     CXXConversionDecl *Conv)
15173{
assert(!Conv->getParent()->isGenericLambda())((void)0);

SynthesizedFunctionScope Scope(*this, Conv);

// Copy-initialize the lambda object as needed to capture it.
Expr *This = ActOnCXXThis(CurrentLocation).get();
Expr *DerefThis =CreateBuiltinUnaryOp(CurrentLocation, UO_Deref, This).get();

ExprResult BuildBlock = BuildBlockForLambdaConversion(CurrentLocation,
                                                      Conv->getLocation(),
                                                      Conv, DerefThis);

// If we're not under ARC, make sure we still get the _Block_copy/autorelease
// behavior.  Note that only the general conversion function does this
// (since it's unusable otherwise); in the case where we inline the
// block literal, it has block literal lifetime semantics.
if (!BuildBlock.isInvalid() && !getLangOpts().ObjCAutoRefCount)
  BuildBlock = ImplicitCastExpr::Create(
      Context, BuildBlock.get()->getType(), CK_CopyAndAutoreleaseBlockObject,
      BuildBlock.get(), nullptr, VK_PRValue, FPOptionsOverride());

if (BuildBlock.isInvalid()) {
  Diag(CurrentLocation, diag::note_lambda_to_block_conv);
  Conv->setInvalidDecl();
  return;
}

// Create the return statement that returns the block from the conversion
// function.
StmtResult Return = BuildReturnStmt(Conv->getLocation(), BuildBlock.get());
if (Return.isInvalid()) {
  Diag(CurrentLocation, diag::note_lambda_to_block_conv);
  Conv->setInvalidDecl();
  return;
}

// Set the body of the conversion function.
Stmt *ReturnS = Return.get();
Conv->setBody(CompoundStmt::Create(Context, ReturnS, Conv->getLocation(),
                                   Conv->getLocation()));
Conv->markUsed(Context);

// We're done; notify the mutation listener, if any.
if (ASTMutationListener *L = getASTMutationListener()) {
  L->CompletedImplicitDefinition(Conv);
}
15220}

15222/// Determine whether the given list arguments contains exactly one
15223/// "real" (non-default) argument.
15224static bool hasOneRealArgument(MultiExprArg Args) {
switch (Args.size()) {
case 0:
  return false;

default:
  if (!Args[1]->isDefaultArgument())
    return false;

  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case 1:
  return !Args[0]->isDefaultArgument();
}

return false;
15239}

15241ExprResult
15242Sema::BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                          NamedDecl *FoundDecl,
                          CXXConstructorDecl *Constructor,
                          MultiExprArg ExprArgs,
                          bool HadMultipleCandidates,
                          bool IsListInitialization,
                          bool IsStdInitListInitialization,
                          bool RequiresZeroInit,
                          unsigned ConstructKind,
                          SourceRange ParenRange) {
bool Elidable = false;

// C++0x [class.copy]p34:
//   When certain criteria are met, an implementation is allowed to
//   omit the copy/move construction of a class object, even if the
//   copy/move constructor and/or destructor for the object have
//   side effects. [...]
//     - when a temporary class object that has not been bound to a
//       reference (12.2) would be copied/moved to a class object
//       with the same cv-unqualified type, the copy/move operation
//       can be omitted by constructing the temporary object
//       directly into the target of the omitted copy/move
if (ConstructKind == CXXConstructExpr::CK_Complete && Constructor &&
    // FIXME: Converting constructors should also be accepted.
    // But to fix this, the logic that digs down into a CXXConstructExpr
    // to find the source object needs to handle it.
    // Right now it assumes the source object is passed directly as the
    // first argument.
    Constructor->isCopyOrMoveConstructor() && hasOneRealArgument(ExprArgs)) {
  Expr *SubExpr = ExprArgs[0];
  // FIXME: Per above, this is also incorrect if we want to accept
  //        converting constructors, as isTemporaryObject will
  //        reject temporaries with different type from the
  //        CXXRecord itself.
  Elidable = SubExpr->isTemporaryObject(
      Context, cast<CXXRecordDecl>(FoundDecl->getDeclContext()));
}

return BuildCXXConstructExpr(ConstructLoc, DeclInitType,
                             FoundDecl, Constructor,
                             Elidable, ExprArgs, HadMultipleCandidates,
                             IsListInitialization,
                             IsStdInitListInitialization, RequiresZeroInit,
                             ConstructKind, ParenRange);
15286}

15288ExprResult
15289Sema::BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                          NamedDecl *FoundDecl,
                          CXXConstructorDecl *Constructor,
                          bool Elidable,
                          MultiExprArg ExprArgs,
                          bool HadMultipleCandidates,
                          bool IsListInitialization,
                          bool IsStdInitListInitialization,
                          bool RequiresZeroInit,
                          unsigned ConstructKind,
                          SourceRange ParenRange) {
if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl)) {
  Constructor = findInheritingConstructor(ConstructLoc, Constructor, Shadow);
  if (DiagnoseUseOfDecl(Constructor, ConstructLoc))
    return ExprError();
}

return BuildCXXConstructExpr(
    ConstructLoc, DeclInitType, Constructor, Elidable, ExprArgs,
    HadMultipleCandidates, IsListInitialization, IsStdInitListInitialization,
    RequiresZeroInit, ConstructKind, ParenRange);
15310}

15312/// BuildCXXConstructExpr - Creates a complete call to a constructor,
15313/// including handling of its default argument expressions.
15314ExprResult
15315Sema::BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                          CXXConstructorDecl *Constructor,
                          bool Elidable,
                          MultiExprArg ExprArgs,
                          bool HadMultipleCandidates,
                          bool IsListInitialization,
                          bool IsStdInitListInitialization,
                          bool RequiresZeroInit,
                          unsigned ConstructKind,
                          SourceRange ParenRange) {
assert(declaresSameEntity(((void)0)
           Constructor->getParent(),((void)0)
           DeclInitType->getBaseElementTypeUnsafe()->getAsCXXRecordDecl()) &&((void)0)
       "given constructor for wrong type")((void)0);
MarkFunctionReferenced(ConstructLoc, Constructor);
if (getLangOpts().CUDA && !CheckCUDACall(ConstructLoc, Constructor))
  return ExprError();
if (getLangOpts().SYCLIsDevice &&
    !checkSYCLDeviceFunction(ConstructLoc, Constructor))
  return ExprError();

return CheckForImmediateInvocation(
    CXXConstructExpr::Create(
        Context, DeclInitType, ConstructLoc, Constructor, Elidable, ExprArgs,
        HadMultipleCandidates, IsListInitialization,
        IsStdInitListInitialization, RequiresZeroInit,
        static_cast<CXXConstructExpr::ConstructionKind>(ConstructKind),
        ParenRange),
    Constructor);
15344}

15346ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) {
assert(Field->hasInClassInitializer())((void)0);

// If we already have the in-class initializer nothing needs to be done.
if (Field->getInClassInitializer())
  return CXXDefaultInitExpr::Create(Context, Loc, Field, CurContext);

// If we might have already tried and failed to instantiate, don't try again.
if (Field->isInvalidDecl())
  return ExprError();

// Maybe we haven't instantiated the in-class initializer. Go check the
// pattern FieldDecl to see if it has one.
CXXRecordDecl *ParentRD = cast<CXXRecordDecl>(Field->getParent());

if (isTemplateInstantiation(ParentRD->getTemplateSpecializationKind())) {
  CXXRecordDecl *ClassPattern = ParentRD->getTemplateInstantiationPattern();
  DeclContext::lookup_result Lookup =
      ClassPattern->lookup(Field->getDeclName());

  FieldDecl *Pattern = nullptr;
  for (auto L : Lookup) {
    if (isa<FieldDecl>(L)) {
      Pattern = cast<FieldDecl>(L);
      break;
    }
  }
  assert(Pattern && "We must have set the Pattern!")((void)0);

  if (!Pattern->hasInClassInitializer() ||
      InstantiateInClassInitializer(Loc, Field, Pattern,
                                    getTemplateInstantiationArgs(Field))) {
    // Don't diagnose this again.
    Field->setInvalidDecl();
    return ExprError();
  }
  return CXXDefaultInitExpr::Create(Context, Loc, Field, CurContext);
}

// DR1351:
//   If the brace-or-equal-initializer of a non-static data member
//   invokes a defaulted default constructor of its class or of an
//   enclosing class in a potentially evaluated subexpression, the
//   program is ill-formed.
//
// This resolution is unworkable: the exception specification of the
// default constructor can be needed in an unevaluated context, in
// particular, in the operand of a noexcept-expression, and we can be
// unable to compute an exception specification for an enclosed class.
//
// Any attempt to resolve the exception specification of a defaulted default
// constructor before the initializer is lexically complete will ultimately
// come here at which point we can diagnose it.
RecordDecl *OutermostClass = ParentRD->getOuterLexicalRecordContext();
Diag(Loc, diag::err_default_member_initializer_not_yet_parsed)
    << OutermostClass << Field;
Diag(Field->getEndLoc(),
     diag::note_default_member_initializer_not_yet_parsed);
// Recover by marking the field invalid, unless we're in a SFINAE context.
if (!isSFINAEContext())
  Field->setInvalidDecl();
return ExprError();
15408}

15410void Sema::FinalizeVarWithDestructor(VarDecl *VD, const RecordType *Record) {
if (VD->isInvalidDecl()) return;
// If initializing the variable failed, don't also diagnose problems with
// the desctructor, they're likely related.
if (VD->getInit() && VD->getInit()->containsErrors())
  return;

CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Record->getDecl());
if (ClassDecl->isInvalidDecl()) return;
if (ClassDecl->hasIrrelevantDestructor()) return;
if (ClassDecl->isDependentContext()) return;

if (VD->isNoDestroy(getASTContext()))
  return;

CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl);

// If this is an array, we'll require the destructor during initialization, so
// we can skip over this. We still want to emit exit-time destructor warnings
// though.
if (!VD->getType()->isArrayType()) {
  MarkFunctionReferenced(VD->getLocation(), Destructor);
  CheckDestructorAccess(VD->getLocation(), Destructor,
                        PDiag(diag::err_access_dtor_var)
                            << VD->getDeclName() << VD->getType());
  DiagnoseUseOfDecl(Destructor, VD->getLocation());
}

if (Destructor->isTrivial()) return;

// If the destructor is constexpr, check whether the variable has constant
// destruction now.
if (Destructor->isConstexpr()) {
  bool HasConstantInit = false;
  if (VD->getInit() && !VD->getInit()->isValueDependent())
    HasConstantInit = VD->evaluateValue();
  SmallVector<PartialDiagnosticAt, 8> Notes;
  if (!VD->evaluateDestruction(Notes) && VD->isConstexpr() &&
      HasConstantInit) {
    Diag(VD->getLocation(),
         diag::err_constexpr_var_requires_const_destruction) << VD;
    for (unsigned I = 0, N = Notes.size(); I != N; ++I)
      Diag(Notes[I].first, Notes[I].second);
  }
}

if (!VD->hasGlobalStorage()) return;

// Emit warning for non-trivial dtor in global scope (a real global,
// class-static, function-static).
Diag(VD->getLocation(), diag::warn_exit_time_destructor);

// TODO: this should be re-enabled for static locals by !CXAAtExit
if (!VD->isStaticLocal())
  Diag(VD->getLocation(), diag::warn_global_destructor);
15465}

15467/// Given a constructor and the set of arguments provided for the
15468/// constructor, convert the arguments and add any required default arguments
15469/// to form a proper call to this constructor.
15470///
15471/// \returns true if an error occurred, false otherwise.
15472bool Sema::CompleteConstructorCall(CXXConstructorDecl *Constructor,
                                 QualType DeclInitType, MultiExprArg ArgsPtr,
                                 SourceLocation Loc,
                                 SmallVectorImpl<Expr *> &ConvertedArgs,
                                 bool AllowExplicit,
                                 bool IsListInitialization) {
// FIXME: This duplicates a lot of code from Sema::ConvertArgumentsForCall.
unsigned NumArgs = ArgsPtr.size();
Expr **Args = ArgsPtr.data();

const auto *Proto = Constructor->getType()->castAs<FunctionProtoType>();
unsigned NumParams = Proto->getNumParams();

// If too few arguments are available, we'll fill in the rest with defaults.
if (NumArgs < NumParams)
  ConvertedArgs.reserve(NumParams);
else
  ConvertedArgs.reserve(NumArgs);

VariadicCallType CallType =
  Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
SmallVector<Expr *, 8> AllArgs;
bool Invalid = GatherArgumentsForCall(Loc, Constructor,
                                      Proto, 0,
                                      llvm::makeArrayRef(Args, NumArgs),
                                      AllArgs,
                                      CallType, AllowExplicit,
                                      IsListInitialization);
ConvertedArgs.append(AllArgs.begin(), AllArgs.end());

DiagnoseSentinelCalls(Constructor, Loc, AllArgs);

CheckConstructorCall(Constructor, DeclInitType,
                     llvm::makeArrayRef(AllArgs.data(), AllArgs.size()),
                     Proto, Loc);

return Invalid;
15509}

15511static inline bool
15512CheckOperatorNewDeleteDeclarationScope(Sema &SemaRef,
                                     const FunctionDecl *FnDecl) {
const DeclContext *DC = FnDecl->getDeclContext()->getRedeclContext();
if (isa<NamespaceDecl>(DC)) {
  return SemaRef.Diag(FnDecl->getLocation(),
                      diag::err_operator_new_delete_declared_in_namespace)
    << FnDecl->getDeclName();
}

if (isa<TranslationUnitDecl>(DC) &&
    FnDecl->getStorageClass() == SC_Static) {
  return SemaRef.Diag(FnDecl->getLocation(),
                      diag::err_operator_new_delete_declared_static)
    << FnDecl->getDeclName();
}

return false;
15529}

15531static CanQualType RemoveAddressSpaceFromPtr(Sema &SemaRef,
                                           const PointerType *PtrTy) {
auto &Ctx = SemaRef.Context;
Qualifiers PtrQuals = PtrTy->getPointeeType().getQualifiers();
PtrQuals.removeAddressSpace();
return Ctx.getPointerType(Ctx.getCanonicalType(Ctx.getQualifiedType(
    PtrTy->getPointeeType().getUnqualifiedType(), PtrQuals)));
15538}

15540static inline bool
15541CheckOperatorNewDeleteTypes(Sema &SemaRef, const FunctionDecl *FnDecl,
                          CanQualType ExpectedResultType,
                          CanQualType ExpectedFirstParamType,
                          unsigned DependentParamTypeDiag,
                          unsigned InvalidParamTypeDiag) {
QualType ResultType =
    FnDecl->getType()->castAs<FunctionType>()->getReturnType();

if (SemaRef.getLangOpts().OpenCLCPlusPlus) {
  // The operator is valid on any address space for OpenCL.
  // Drop address space from actual and expected result types.
  if (const auto *PtrTy = ResultType->getAs<PointerType>())
    ResultType = RemoveAddressSpaceFromPtr(SemaRef, PtrTy);

  if (auto ExpectedPtrTy = ExpectedResultType->getAs<PointerType>())
    ExpectedResultType = RemoveAddressSpaceFromPtr(SemaRef, ExpectedPtrTy);
}

// Check that the result type is what we expect.
if (SemaRef.Context.getCanonicalType(ResultType) != ExpectedResultType) {
  // Reject even if the type is dependent; an operator delete function is
  // required to have a non-dependent result type.
  return SemaRef.Diag(
             FnDecl->getLocation(),
             ResultType->isDependentType()
                 ? diag::err_operator_new_delete_dependent_result_type
                 : diag::err_operator_new_delete_invalid_result_type)
         << FnDecl->getDeclName() << ExpectedResultType;
}

// A function template must have at least 2 parameters.
if (FnDecl->getDescribedFunctionTemplate() && FnDecl->getNumParams() < 2)
  return SemaRef.Diag(FnDecl->getLocation(),
                    diag::err_operator_new_delete_template_too_few_parameters)
      << FnDecl->getDeclName();

// The function decl must have at least 1 parameter.
if (FnDecl->getNumParams() == 0)
  return SemaRef.Diag(FnDecl->getLocation(),
                      diag::err_operator_new_delete_too_few_parameters)
    << FnDecl->getDeclName();

QualType FirstParamType = FnDecl->getParamDecl(0)->getType();
if (SemaRef.getLangOpts().OpenCLCPlusPlus) {
  // The operator is valid on any address space for OpenCL.
  // Drop address space from actual and expected first parameter types.
  if (const auto *PtrTy =
          FnDecl->getParamDecl(0)->getType()->getAs<PointerType>())
    FirstParamType = RemoveAddressSpaceFromPtr(SemaRef, PtrTy);

  if (auto ExpectedPtrTy = ExpectedFirstParamType->getAs<PointerType>())
    ExpectedFirstParamType =
        RemoveAddressSpaceFromPtr(SemaRef, ExpectedPtrTy);
}

// Check that the first parameter type is what we expect.
if (SemaRef.Context.getCanonicalType(FirstParamType).getUnqualifiedType() !=
    ExpectedFirstParamType) {
  // The first parameter type is not allowed to be dependent. As a tentative
  // DR resolution, we allow a dependent parameter type if it is the right
  // type anyway, to allow destroying operator delete in class templates.
  return SemaRef.Diag(FnDecl->getLocation(), FirstParamType->isDependentType()
                                                 ? DependentParamTypeDiag
                                                 : InvalidParamTypeDiag)
         << FnDecl->getDeclName() << ExpectedFirstParamType;
}

return false;
15609}

15611static bool
15612CheckOperatorNewDeclaration(Sema &SemaRef, const FunctionDecl *FnDecl) {
// C++ [basic.stc.dynamic.allocation]p1:
//   A program is ill-formed if an allocation function is declared in a
//   namespace scope other than global scope or declared static in global
//   scope.
if (CheckOperatorNewDeleteDeclarationScope(SemaRef, FnDecl))
  return true;

CanQualType SizeTy =
  SemaRef.Context.getCanonicalType(SemaRef.Context.getSizeType());

// C++ [basic.stc.dynamic.allocation]p1:
//  The return type shall be void*. The first parameter shall have type
//  std::size_t.
if (CheckOperatorNewDeleteTypes(SemaRef, FnDecl, SemaRef.Context.VoidPtrTy,
                                SizeTy,
                                diag::err_operator_new_dependent_param_type,
                                diag::err_operator_new_param_type))
  return true;

// C++ [basic.stc.dynamic.allocation]p1:
//  The first parameter shall not have an associated default argument.
if (FnDecl->getParamDecl(0)->hasDefaultArg())
  return SemaRef.Diag(FnDecl->getLocation(),
                      diag::err_operator_new_default_arg)
    << FnDecl->getDeclName() << FnDecl->getParamDecl(0)->getDefaultArgRange();

return false;
15640}

15642static bool
15643CheckOperatorDeleteDeclaration(Sema &SemaRef, FunctionDecl *FnDecl) {
// C++ [basic.stc.dynamic.deallocation]p1:
//   A program is ill-formed if deallocation functions are declared in a
//   namespace scope other than global scope or declared static in global
//   scope.
if (CheckOperatorNewDeleteDeclarationScope(SemaRef, FnDecl))
  return true;

auto *MD = dyn_cast<CXXMethodDecl>(FnDecl);

// C++ P0722:
//   Within a class C, the first parameter of a destroying operator delete
//   shall be of type C *. The first parameter of any other deallocation
//   function shall be of type void *.
CanQualType ExpectedFirstParamType =
    MD && MD->isDestroyingOperatorDelete()
        ? SemaRef.Context.getCanonicalType(SemaRef.Context.getPointerType(
              SemaRef.Context.getRecordType(MD->getParent())))
        : SemaRef.Context.VoidPtrTy;

// C++ [basic.stc.dynamic.deallocation]p2:
//   Each deallocation function shall return void
if (CheckOperatorNewDeleteTypes(
        SemaRef, FnDecl, SemaRef.Context.VoidTy, ExpectedFirstParamType,
        diag::err_operator_delete_dependent_param_type,
        diag::err_operator_delete_param_type))
  return true;

// C++ P0722:
//   A destroying operator delete shall be a usual deallocation function.
if (MD && !MD->getParent()->isDependentContext() &&
    MD->isDestroyingOperatorDelete() &&
    !SemaRef.isUsualDeallocationFunction(MD)) {
  SemaRef.Diag(MD->getLocation(),
               diag::err_destroying_operator_delete_not_usual);
  return true;
}

return false;
15682}

15684/// CheckOverloadedOperatorDeclaration - Check whether the declaration
15685/// of this overloaded operator is well-formed. If so, returns false;
15686/// otherwise, emits appropriate diagnostics and returns true.
15687bool Sema::CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl) {
assert(FnDecl && FnDecl->isOverloadedOperator() &&((void)0)
       "Expected an overloaded operator declaration")((void)0);

OverloadedOperatorKind Op = FnDecl->getOverloadedOperator();

// C++ [over.oper]p5:
//   The allocation and deallocation functions, operator new,
//   operator new[], operator delete and operator delete[], are
//   described completely in 3.7.3. The attributes and restrictions
//   found in the rest of this subclause do not apply to them unless
//   explicitly stated in 3.7.3.
if (Op == OO_Delete || Op == OO_Array_Delete)
  return CheckOperatorDeleteDeclaration(*this, FnDecl);

if (Op == OO_New || Op == OO_Array_New)
  return CheckOperatorNewDeclaration(*this, FnDecl);

// C++ [over.oper]p6:
//   An operator function shall either be a non-static member
//   function or be a non-member function and have at least one
//   parameter whose type is a class, a reference to a class, an
//   enumeration, or a reference to an enumeration.
if (CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(FnDecl)) {
  if (MethodDecl->isStatic())
    return Diag(FnDecl->getLocation(),
                diag::err_operator_overload_static) << FnDecl->getDeclName();
} else {
  bool ClassOrEnumParam = false;
  for (auto Param : FnDecl->parameters()) {
    QualType ParamType = Param->getType().getNonReferenceType();
    if (ParamType->isDependentType() || ParamType->isRecordType() ||
        ParamType->isEnumeralType()) {
      ClassOrEnumParam = true;
      break;
    }
  }

  if (!ClassOrEnumParam)
    return Diag(FnDecl->getLocation(),
                diag::err_operator_overload_needs_class_or_enum)
      << FnDecl->getDeclName();
}

// C++ [over.oper]p8:
//   An operator function cannot have default arguments (8.3.6),
//   except where explicitly stated below.
//
// Only the function-call operator allows default arguments
// (C++ [over.call]p1).
if (Op != OO_Call) {
  for (auto Param : FnDecl->parameters()) {
    if (Param->hasDefaultArg())
      return Diag(Param->getLocation(),
                  diag::err_operator_overload_default_arg)
        << FnDecl->getDeclName() << Param->getDefaultArgRange();
  }
}

static const bool OperatorUses[NUM_OVERLOADED_OPERATORS][3] = {
  { false, false, false }
15748#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
  , { Unary, Binary, MemberOnly }
15750#include "clang/Basic/OperatorKinds.def"
};

bool CanBeUnaryOperator = OperatorUses[Op][0];
bool CanBeBinaryOperator = OperatorUses[Op][1];
bool MustBeMemberOperator = OperatorUses[Op][2];

// C++ [over.oper]p8:
//   [...] Operator functions cannot have more or fewer parameters
//   than the number required for the corresponding operator, as
//   described in the rest of this subclause.
unsigned NumParams = FnDecl->getNumParams()
                   + (isa<CXXMethodDecl>(FnDecl)? 1 : 0);
if (Op != OO_Call &&
    ((NumParams == 1 && !CanBeUnaryOperator) ||
     (NumParams == 2 && !CanBeBinaryOperator) ||
     (NumParams < 1) || (NumParams > 2))) {
  // We have the wrong number of parameters.
  unsigned ErrorKind;
  if (CanBeUnaryOperator && CanBeBinaryOperator) {
    ErrorKind = 2;  // 2 -> unary or binary.
  } else if (CanBeUnaryOperator) {
    ErrorKind = 0;  // 0 -> unary
  } else {
    assert(CanBeBinaryOperator &&((void)0)
           "All non-call overloaded operators are unary or binary!")((void)0);
    ErrorKind = 1;  // 1 -> binary
  }

  return Diag(FnDecl->getLocation(), diag::err_operator_overload_must_be)
    << FnDecl->getDeclName() << NumParams << ErrorKind;
}

// Overloaded operators other than operator() cannot be variadic.
if (Op != OO_Call &&
    FnDecl->getType()->castAs<FunctionProtoType>()->isVariadic()) {
  return Diag(FnDecl->getLocation(), diag::err_operator_overload_variadic)
    << FnDecl->getDeclName();
}

// Some operators must be non-static member functions.
if (MustBeMemberOperator && !isa<CXXMethodDecl>(FnDecl)) {
  return Diag(FnDecl->getLocation(),
              diag::err_operator_overload_must_be_member)
    << FnDecl->getDeclName();
}

// C++ [over.inc]p1:
//   The user-defined function called operator++ implements the
//   prefix and postfix ++ operator. If this function is a member
//   function with no parameters, or a non-member function with one
//   parameter of class or enumeration type, it defines the prefix
//   increment operator ++ for objects of that type. If the function
//   is a member function with one parameter (which shall be of type
//   int) or a non-member function with two parameters (the second
//   of which shall be of type int), it defines the postfix
//   increment operator ++ for objects of that type.
if ((Op == OO_PlusPlus || Op == OO_MinusMinus) && NumParams == 2) {
  ParmVarDecl *LastParam = FnDecl->getParamDecl(FnDecl->getNumParams() - 1);
  QualType ParamType = LastParam->getType();

  if (!ParamType->isSpecificBuiltinType(BuiltinType::Int) &&
      !ParamType->isDependentType())
    return Diag(LastParam->getLocation(),
                diag::err_operator_overload_post_incdec_must_be_int)
      << LastParam->getType() << (Op == OO_MinusMinus);
}

return false;
15819}

15821static bool
15822checkLiteralOperatorTemplateParameterList(Sema &SemaRef,
                                        FunctionTemplateDecl *TpDecl) {
TemplateParameterList *TemplateParams = TpDecl->getTemplateParameters();

// Must have one or two template parameters.
if (TemplateParams->size() == 1) {
  NonTypeTemplateParmDecl *PmDecl =
      dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(0));

  // The template parameter must be a char parameter pack.
  if (PmDecl && PmDecl->isTemplateParameterPack() &&
      SemaRef.Context.hasSameType(PmDecl->getType(), SemaRef.Context.CharTy))
    return false;

  // C++20 [over.literal]p5:
  //   A string literal operator template is a literal operator template
  //   whose template-parameter-list comprises a single non-type
  //   template-parameter of class type.
  //
  // As a DR resolution, we also allow placeholders for deduced class
  // template specializations.
  if (SemaRef.getLangOpts().CPlusPlus20 &&
      !PmDecl->isTemplateParameterPack() &&
      (PmDecl->getType()->isRecordType() ||
       PmDecl->getType()->getAs<DeducedTemplateSpecializationType>()))
    return false;
} else if (TemplateParams->size() == 2) {
  TemplateTypeParmDecl *PmType =
      dyn_cast<TemplateTypeParmDecl>(TemplateParams->getParam(0));
  NonTypeTemplateParmDecl *PmArgs =
      dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(1));

  // The second template parameter must be a parameter pack with the
  // first template parameter as its type.
  if (PmType && PmArgs && !PmType->isTemplateParameterPack() &&
      PmArgs->isTemplateParameterPack()) {
    const TemplateTypeParmType *TArgs =
        PmArgs->getType()->getAs<TemplateTypeParmType>();
    if (TArgs && TArgs->getDepth() == PmType->getDepth() &&
        TArgs->getIndex() == PmType->getIndex()) {
      if (!SemaRef.inTemplateInstantiation())
        SemaRef.Diag(TpDecl->getLocation(),
                     diag::ext_string_literal_operator_template);
      return false;
    }
  }
}

SemaRef.Diag(TpDecl->getTemplateParameters()->getSourceRange().getBegin(),
             diag::err_literal_operator_template)
    << TpDecl->getTemplateParameters()->getSourceRange();
return true;
15874}

15876/// CheckLiteralOperatorDeclaration - Check whether the declaration
15877/// of this literal operator function is well-formed. If so, returns
15878/// false; otherwise, emits appropriate diagnostics and returns true.
15879bool Sema::CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl) {
if (isa<CXXMethodDecl>(FnDecl)) {
  Diag(FnDecl->getLocation(), diag::err_literal_operator_outside_namespace)
    << FnDecl->getDeclName();
  return true;
}

if (FnDecl->isExternC()) {
  Diag(FnDecl->getLocation(), diag::err_literal_operator_extern_c);
  if (const LinkageSpecDecl *LSD =
          FnDecl->getDeclContext()->getExternCContext())
    Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
  return true;
}

// This might be the definition of a literal operator template.
FunctionTemplateDecl *TpDecl = FnDecl->getDescribedFunctionTemplate();

// This might be a specialization of a literal operator template.
if (!TpDecl)
  TpDecl = FnDecl->getPrimaryTemplate();

// template <char...> type operator "" name() and
// template <class T, T...> type operator "" name() are the only valid
// template signatures, and the only valid signatures with no parameters.
//
// C++20 also allows template <SomeClass T> type operator "" name().
if (TpDecl) {
  if (FnDecl->param_size() != 0) {
    Diag(FnDecl->getLocation(),
         diag::err_literal_operator_template_with_params);
    return true;
  }

  if (checkLiteralOperatorTemplateParameterList(*this, TpDecl))
    return true;

} else if (FnDecl->param_size() == 1) {
  const ParmVarDecl *Param = FnDecl->getParamDecl(0);

  QualType ParamType = Param->getType().getUnqualifiedType();

  // Only unsigned long long int, long double, any character type, and const
  // char * are allowed as the only parameters.
  if (ParamType->isSpecificBuiltinType(BuiltinType::ULongLong) ||
      ParamType->isSpecificBuiltinType(BuiltinType::LongDouble) ||
      Context.hasSameType(ParamType, Context.CharTy) ||
      Context.hasSameType(ParamType, Context.WideCharTy) ||
      Context.hasSameType(ParamType, Context.Char8Ty) ||
      Context.hasSameType(ParamType, Context.Char16Ty) ||
      Context.hasSameType(ParamType, Context.Char32Ty)) {
  } else if (const PointerType *Ptr = ParamType->getAs<PointerType>()) {
    QualType InnerType = Ptr->getPointeeType();

    // Pointer parameter must be a const char *.
    if (!(Context.hasSameType(InnerType.getUnqualifiedType(),
                              Context.CharTy) &&
          InnerType.isConstQualified() && !InnerType.isVolatileQualified())) {
      Diag(Param->getSourceRange().getBegin(),
           diag::err_literal_operator_param)
          << ParamType << "'const char *'" << Param->getSourceRange();
      return true;
    }

  } else if (ParamType->isRealFloatingType()) {
    Diag(Param->getSourceRange().getBegin(), diag::err_literal_operator_param)
        << ParamType << Context.LongDoubleTy << Param->getSourceRange();
    return true;

  } else if (ParamType->isIntegerType()) {
    Diag(Param->getSourceRange().getBegin(), diag::err_literal_operator_param)
        << ParamType << Context.UnsignedLongLongTy << Param->getSourceRange();
    return true;

  } else {
    Diag(Param->getSourceRange().getBegin(),
         diag::err_literal_operator_invalid_param)
        << ParamType << Param->getSourceRange();
    return true;
  }

} else if (FnDecl->param_size() == 2) {
  FunctionDecl::param_iterator Param = FnDecl->param_begin();

  // First, verify that the first parameter is correct.

  QualType FirstParamType = (*Param)->getType().getUnqualifiedType();

  // Two parameter function must have a pointer to const as a
  // first parameter; let's strip those qualifiers.
  const PointerType *PT = FirstParamType->getAs<PointerType>();

  if (!PT) {
    Diag((*Param)->getSourceRange().getBegin(),
         diag::err_literal_operator_param)
        << FirstParamType << "'const char *'" << (*Param)->getSourceRange();
    return true;
  }

  QualType PointeeType = PT->getPointeeType();
  // First parameter must be const
  if (!PointeeType.isConstQualified() || PointeeType.isVolatileQualified()) {
    Diag((*Param)->getSourceRange().getBegin(),
         diag::err_literal_operator_param)
        << FirstParamType << "'const char *'" << (*Param)->getSourceRange();
    return true;
  }

  QualType InnerType = PointeeType.getUnqualifiedType();
  // Only const char *, const wchar_t*, const char8_t*, const char16_t*, and
  // const char32_t* are allowed as the first parameter to a two-parameter
  // function
  if (!(Context.hasSameType(InnerType, Context.CharTy) ||
        Context.hasSameType(InnerType, Context.WideCharTy) ||
        Context.hasSameType(InnerType, Context.Char8Ty) ||
        Context.hasSameType(InnerType, Context.Char16Ty) ||
        Context.hasSameType(InnerType, Context.Char32Ty))) {
    Diag((*Param)->getSourceRange().getBegin(),
         diag::err_literal_operator_param)
        << FirstParamType << "'const char *'" << (*Param)->getSourceRange();
    return true;
  }

  // Move on to the second and final parameter.
  ++Param;

  // The second parameter must be a std::size_t.
  QualType SecondParamType = (*Param)->getType().getUnqualifiedType();
  if (!Context.hasSameType(SecondParamType, Context.getSizeType())) {
    Diag((*Param)->getSourceRange().getBegin(),
         diag::err_literal_operator_param)
        << SecondParamType << Context.getSizeType()
        << (*Param)->getSourceRange();
    return true;
  }
} else {
  Diag(FnDecl->getLocation(), diag::err_literal_operator_bad_param_count);
  return true;
}

// Parameters are good.

// A parameter-declaration-clause containing a default argument is not
// equivalent to any of the permitted forms.
for (auto Param : FnDecl->parameters()) {
  if (Param->hasDefaultArg()) {
    Diag(Param->getDefaultArgRange().getBegin(),
         diag::err_literal_operator_default_argument)
      << Param->getDefaultArgRange();
    break;
  }
}

StringRef LiteralName
  = FnDecl->getDeclName().getCXXLiteralIdentifier()->getName();
if (LiteralName[0] != '_' &&
    !getSourceManager().isInSystemHeader(FnDecl->getLocation())) {
  // C++11 [usrlit.suffix]p1:
  //   Literal suffix identifiers that do not start with an underscore
  //   are reserved for future standardization.
  Diag(FnDecl->getLocation(), diag::warn_user_literal_reserved)
    << StringLiteralParser::isValidUDSuffix(getLangOpts(), LiteralName);
}

return false;
16044}

16046/// ActOnStartLinkageSpecification - Parsed the beginning of a C++
16047/// linkage specification, including the language and (if present)
16048/// the '{'. ExternLoc is the location of the 'extern', Lang is the
16049/// language string literal. LBraceLoc, if valid, provides the location of
16050/// the '{' brace. Otherwise, this linkage specification does not
16051/// have any braces.
16052Decl *Sema::ActOnStartLinkageSpecification(Scope *S, SourceLocation ExternLoc,
                                         Expr *LangStr,
                                         SourceLocation LBraceLoc) {
StringLiteral *Lit = cast<StringLiteral>(LangStr);
if (!Lit->isAscii()) {
  Diag(LangStr->getExprLoc(), diag::err_language_linkage_spec_not_ascii)
    << LangStr->getSourceRange();
  return nullptr;
}

StringRef Lang = Lit->getString();
LinkageSpecDecl::LanguageIDs Language;
if (Lang == "C")
  Language = LinkageSpecDecl::lang_c;
else if (Lang == "C++")
  Language = LinkageSpecDecl::lang_cxx;
else {
  Diag(LangStr->getExprLoc(), diag::err_language_linkage_spec_unknown)
    << LangStr->getSourceRange();
  return nullptr;
}

// FIXME: Add all the various semantics of linkage specifications

LinkageSpecDecl *D = LinkageSpecDecl::Create(Context, CurContext, ExternLoc,
                                             LangStr->getExprLoc(), Language,
                                             LBraceLoc.isValid());
CurContext->addDecl(D);
PushDeclContext(S, D);
return D;
16082}

16084/// ActOnFinishLinkageSpecification - Complete the definition of
16085/// the C++ linkage specification LinkageSpec. If RBraceLoc is
16086/// valid, it's the position of the closing '}' brace in a linkage
16087/// specification that uses braces.
16088Decl *Sema::ActOnFinishLinkageSpecification(Scope *S,
                                          Decl *LinkageSpec,
                                          SourceLocation RBraceLoc) {
if (RBraceLoc.isValid()) {
  LinkageSpecDecl* LSDecl = cast<LinkageSpecDecl>(LinkageSpec);
  LSDecl->setRBraceLoc(RBraceLoc);
}
PopDeclContext();
return LinkageSpec;
16097}

16099Decl *Sema::ActOnEmptyDeclaration(Scope *S,
                                const ParsedAttributesView &AttrList,
                                SourceLocation SemiLoc) {
Decl *ED = EmptyDecl::Create(Context, CurContext, SemiLoc);
// Attribute declarations appertain to empty declaration so we handle
// them here.
ProcessDeclAttributeList(S, ED, AttrList);

CurContext->addDecl(ED);
return ED;
16109}

16111/// Perform semantic analysis for the variable declaration that
16112/// occurs within a C++ catch clause, returning the newly-created
16113/// variable.
16114VarDecl *Sema::BuildExceptionDeclaration(Scope *S,
                                       TypeSourceInfo *TInfo,
                                       SourceLocation StartLoc,
                                       SourceLocation Loc,
                                       IdentifierInfo *Name) {
bool Invalid = false;
QualType ExDeclType = TInfo->getType();

// Arrays and functions decay.
if (ExDeclType->isArrayType())
  ExDeclType = Context.getArrayDecayedType(ExDeclType);
else if (ExDeclType->isFunctionType())
  ExDeclType = Context.getPointerType(ExDeclType);

// C++ 15.3p1: The exception-declaration shall not denote an incomplete type.
// The exception-declaration shall not denote a pointer or reference to an
// incomplete type, other than [cv] void*.
// N2844 forbids rvalue references.
if (!ExDeclType->isDependentType() && ExDeclType->isRValueReferenceType()) {
  Diag(Loc, diag::err_catch_rvalue_ref);
  Invalid = true;
}

if (ExDeclType->isVariablyModifiedType()) {
  Diag(Loc, diag::err_catch_variably_modified) << ExDeclType;
  Invalid = true;
}

QualType BaseType = ExDeclType;
int Mode = 0; // 0 for direct type, 1 for pointer, 2 for reference
unsigned DK = diag::err_catch_incomplete;
if (const PointerType *Ptr = BaseType->getAs<PointerType>()) {
  BaseType = Ptr->getPointeeType();
  Mode = 1;
  DK = diag::err_catch_incomplete_ptr;
} else if (const ReferenceType *Ref = BaseType->getAs<ReferenceType>()) {
  // For the purpose of error recovery, we treat rvalue refs like lvalue refs.
  BaseType = Ref->getPointeeType();
  Mode = 2;
  DK = diag::err_catch_incomplete_ref;
}
if (!Invalid && (Mode == 0 || !BaseType->isVoidType()) &&
    !BaseType->isDependentType() && RequireCompleteType(Loc, BaseType, DK))
  Invalid = true;

if (!Invalid && Mode != 1 && BaseType->isSizelessType()) {
  Diag(Loc, diag::err_catch_sizeless) << (Mode == 2 ? 1 : 0) << BaseType;
  Invalid = true;
}

if (!Invalid && !ExDeclType->isDependentType() &&
    RequireNonAbstractType(Loc, ExDeclType,
                           diag::err_abstract_type_in_decl,
                           AbstractVariableType))
  Invalid = true;

// Only the non-fragile NeXT runtime currently supports C++ catches
// of ObjC types, and no runtime supports catching ObjC types by value.
if (!Invalid && getLangOpts().ObjC) {
  QualType T = ExDeclType;
  if (const ReferenceType *RT = T->getAs<ReferenceType>())
    T = RT->getPointeeType();

  if (T->isObjCObjectType()) {
    Diag(Loc, diag::err_objc_object_catch);
    Invalid = true;
  } else if (T->isObjCObjectPointerType()) {
    // FIXME: should this be a test for macosx-fragile specifically?
    if (getLangOpts().ObjCRuntime.isFragile())
      Diag(Loc, diag::warn_objc_pointer_cxx_catch_fragile);
  }
}

VarDecl *ExDecl = VarDecl::Create(Context, CurContext, StartLoc, Loc, Name,
                                  ExDeclType, TInfo, SC_None);
ExDecl->setExceptionVariable(true);

// In ARC, infer 'retaining' for variables of retainable type.
if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(ExDecl))
  Invalid = true;

if (!Invalid && !ExDeclType->isDependentType()) {
  if (const RecordType *recordType = ExDeclType->getAs<RecordType>()) {
    // Insulate this from anything else we might currently be parsing.
    EnterExpressionEvaluationContext scope(
        *this, ExpressionEvaluationContext::PotentiallyEvaluated);

    // C++ [except.handle]p16:
    //   The object declared in an exception-declaration or, if the
    //   exception-declaration does not specify a name, a temporary (12.2) is
    //   copy-initialized (8.5) from the exception object. [...]
    //   The object is destroyed when the handler exits, after the destruction
    //   of any automatic objects initialized within the handler.
    //
    // We just pretend to initialize the object with itself, then make sure
    // it can be destroyed later.
    QualType initType = Context.getExceptionObjectType(ExDeclType);

    InitializedEntity entity =
      InitializedEntity::InitializeVariable(ExDecl);
    InitializationKind initKind =
      InitializationKind::CreateCopy(Loc, SourceLocation());

    Expr *opaqueValue =
      new (Context) OpaqueValueExpr(Loc, initType, VK_LValue, OK_Ordinary);
    InitializationSequence sequence(*this, entity, initKind, opaqueValue);
    ExprResult result = sequence.Perform(*this, entity, initKind, opaqueValue);
    if (result.isInvalid())
      Invalid = true;
    else {
      // If the constructor used was non-trivial, set this as the
      // "initializer".
      CXXConstructExpr *construct = result.getAs<CXXConstructExpr>();
      if (!construct->getConstructor()->isTrivial()) {
        Expr *init = MaybeCreateExprWithCleanups(construct);
        ExDecl->setInit(init);
      }

      // And make sure it's destructable.
      FinalizeVarWithDestructor(ExDecl, recordType);
    }
  }
}

if (Invalid)
  ExDecl->setInvalidDecl();

return ExDecl;
16242}

16244/// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
16245/// handler.
16246Decl *Sema::ActOnExceptionDeclarator(Scope *S, Declarator &D) {
TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
bool Invalid = D.isInvalidType();

// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
                                    UPPC_ExceptionType)) {
  TInfo = Context.getTrivialTypeSourceInfo(Context.IntTy,
                                           D.getIdentifierLoc());
  Invalid = true;
}

IdentifierInfo *II = D.getIdentifier();
if (NamedDecl *PrevDecl = LookupSingleName(S, II, D.getIdentifierLoc(),
                                           LookupOrdinaryName,
                                           ForVisibleRedeclaration)) {
  // The scope should be freshly made just for us. There is just no way
  // it contains any previous declaration, except for function parameters in
  // a function-try-block's catch statement.
  assert(!S->isDeclScope(PrevDecl))((void)0);
  if (isDeclInScope(PrevDecl, CurContext, S)) {
    Diag(D.getIdentifierLoc(), diag::err_redefinition)
      << D.getIdentifier();
    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
    Invalid = true;
  } else if (PrevDecl->isTemplateParameter())
    // Maybe we will complain about the shadowed template parameter.
    DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
}

if (D.getCXXScopeSpec().isSet() && !Invalid) {
  Diag(D.getIdentifierLoc(), diag::err_qualified_catch_declarator)
    << D.getCXXScopeSpec().getRange();
  Invalid = true;
}

VarDecl *ExDecl = BuildExceptionDeclaration(
    S, TInfo, D.getBeginLoc(), D.getIdentifierLoc(), D.getIdentifier());
if (Invalid)
  ExDecl->setInvalidDecl();

// Add the exception declaration into this scope.
if (II)
  PushOnScopeChains(ExDecl, S);
else
  CurContext->addDecl(ExDecl);

ProcessDeclAttributes(S, ExDecl, D);
return ExDecl;
16295}

16297Decl *Sema::ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                       Expr *AssertExpr,
                                       Expr *AssertMessageExpr,
                                       SourceLocation RParenLoc) {
StringLiteral *AssertMessage =
    AssertMessageExpr ? cast<StringLiteral>(AssertMessageExpr) : nullptr;

if (DiagnoseUnexpandedParameterPack(AssertExpr, UPPC_StaticAssertExpression))
  return nullptr;

return BuildStaticAssertDeclaration(StaticAssertLoc, AssertExpr,
                                    AssertMessage, RParenLoc, false);
16309}

16311Decl *Sema::BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                       Expr *AssertExpr,
                                       StringLiteral *AssertMessage,
                                       SourceLocation RParenLoc,
                                       bool Failed) {
assert(AssertExpr != nullptr && "Expected non-null condition")((void)0);
if (!AssertExpr->isTypeDependent() && !AssertExpr->isValueDependent() &&
    !Failed) {
  // In a static_assert-declaration, the constant-expression shall be a
  // constant expression that can be contextually converted to bool.
  ExprResult Converted = PerformContextuallyConvertToBool(AssertExpr);
  if (Converted.isInvalid())
    Failed = true;

  ExprResult FullAssertExpr =
      ActOnFinishFullExpr(Converted.get(), StaticAssertLoc,
                          /*DiscardedValue*/ false,
                          /*IsConstexpr*/ true);
  if (FullAssertExpr.isInvalid())
    Failed = true;
  else
    AssertExpr = FullAssertExpr.get();

  llvm::APSInt Cond;
  if (!Failed && VerifyIntegerConstantExpression(
                     AssertExpr, &Cond,
                     diag::err_static_assert_expression_is_not_constant)
                     .isInvalid())
    Failed = true;

  if (!Failed && !Cond) {
    SmallString<256> MsgBuffer;
    llvm::raw_svector_ostream Msg(MsgBuffer);
    if (AssertMessage)
      AssertMessage->printPretty(Msg, nullptr, getPrintingPolicy());

    Expr *InnerCond = nullptr;
    std::string InnerCondDescription;
    std::tie(InnerCond, InnerCondDescription) =
      findFailedBooleanCondition(Converted.get());
    if (InnerCond && isa<ConceptSpecializationExpr>(InnerCond)) {
      // Drill down into concept specialization expressions to see why they
      // weren't satisfied.
      Diag(StaticAssertLoc, diag::err_static_assert_failed)
        << !AssertMessage << Msg.str() << AssertExpr->getSourceRange();
      ConstraintSatisfaction Satisfaction;
      if (!CheckConstraintSatisfaction(InnerCond, Satisfaction))
        DiagnoseUnsatisfiedConstraint(Satisfaction);
    } else if (InnerCond && !isa<CXXBoolLiteralExpr>(InnerCond)
                         && !isa<IntegerLiteral>(InnerCond)) {
      Diag(StaticAssertLoc, diag::err_static_assert_requirement_failed)
        << InnerCondDescription << !AssertMessage
        << Msg.str() << InnerCond->getSourceRange();
    } else {
      Diag(StaticAssertLoc, diag::err_static_assert_failed)
        << !AssertMessage << Msg.str() << AssertExpr->getSourceRange();
    }
    Failed = true;
  }
} else {
  ExprResult FullAssertExpr = ActOnFinishFullExpr(AssertExpr, StaticAssertLoc,
                                                  /*DiscardedValue*/false,
                                                  /*IsConstexpr*/true);
  if (FullAssertExpr.isInvalid())
    Failed = true;
  else
    AssertExpr = FullAssertExpr.get();
}

Decl *Decl = StaticAssertDecl::Create(Context, CurContext, StaticAssertLoc,
                                      AssertExpr, AssertMessage, RParenLoc,
                                      Failed);

CurContext->addDecl(Decl);
return Decl;
16386}

16388/// Perform semantic analysis of the given friend type declaration.
16389///
16390/// \returns A friend declaration that.
16391FriendDecl *Sema::CheckFriendTypeDecl(SourceLocation LocStart,
                                    SourceLocation FriendLoc,
                                    TypeSourceInfo *TSInfo) {
assert(TSInfo && "NULL TypeSourceInfo for friend type declaration")((void)0);

QualType T = TSInfo->getType();
SourceRange TypeRange = TSInfo->getTypeLoc().getLocalSourceRange();

// C++03 [class.friend]p2:
//   An elaborated-type-specifier shall be used in a friend declaration
//   for a class.*
//
//   * The class-key of the elaborated-type-specifier is required.
if (!CodeSynthesisContexts.empty()) {
  // Do not complain about the form of friend template types during any kind
  // of code synthesis. For template instantiation, we will have complained
  // when the template was defined.
} else {
  if (!T->isElaboratedTypeSpecifier()) {
    // If we evaluated the type to a record type, suggest putting
    // a tag in front.
    if (const RecordType *RT = T->getAs<RecordType>()) {
      RecordDecl *RD = RT->getDecl();

      SmallString<16> InsertionText(" ");
      InsertionText += RD->getKindName();

      Diag(TypeRange.getBegin(),
           getLangOpts().CPlusPlus11 ?
             diag::warn_cxx98_compat_unelaborated_friend_type :
             diag::ext_unelaborated_friend_type)
        << (unsigned) RD->getTagKind()
        << T
        << FixItHint::CreateInsertion(getLocForEndOfToken(FriendLoc),
                                      InsertionText);
    } else {
      Diag(FriendLoc,
           getLangOpts().CPlusPlus11 ?
             diag::warn_cxx98_compat_nonclass_type_friend :
             diag::ext_nonclass_type_friend)
        << T
        << TypeRange;
    }
  } else if (T->getAs<EnumType>()) {
    Diag(FriendLoc,
         getLangOpts().CPlusPlus11 ?
           diag::warn_cxx98_compat_enum_friend :
           diag::ext_enum_friend)
      << T
      << TypeRange;
  }

  // C++11 [class.friend]p3:
  //   A friend declaration that does not declare a function shall have one
  //   of the following forms:
  //     friend elaborated-type-specifier ;
  //     friend simple-type-specifier ;
  //     friend typename-specifier ;
  if (getLangOpts().CPlusPlus11 && LocStart != FriendLoc)
    Diag(FriendLoc, diag::err_friend_not_first_in_declaration) << T;
}

//   If the type specifier in a friend declaration designates a (possibly
//   cv-qualified) class type, that class is declared as a friend; otherwise,
//   the friend declaration is ignored.
return FriendDecl::Create(Context, CurContext,
                          TSInfo->getTypeLoc().getBeginLoc(), TSInfo,
                          FriendLoc);
16459}

16461/// Handle a friend tag declaration where the scope specifier was
16462/// templated.
16463Decl *Sema::ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                                  unsigned TagSpec, SourceLocation TagLoc,
                                  CXXScopeSpec &SS, IdentifierInfo *Name,
                                  SourceLocation NameLoc,
                                  const ParsedAttributesView &Attr,
                                  MultiTemplateParamsArg TempParamLists) {
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);

bool IsMemberSpecialization = false;
bool Invalid = false;

if (TemplateParameterList *TemplateParams =
        MatchTemplateParametersToScopeSpecifier(
            TagLoc, NameLoc, SS, nullptr, TempParamLists, /*friend*/ true,
            IsMemberSpecialization, Invalid)) {
  if (TemplateParams->size() > 0) {
    // This is a declaration of a class template.
    if (Invalid)
      return nullptr;

    return CheckClassTemplate(S, TagSpec, TUK_Friend, TagLoc, SS, Name,
                              NameLoc, Attr, TemplateParams, AS_public,
                              /*ModulePrivateLoc=*/SourceLocation(),
                              FriendLoc, TempParamLists.size() - 1,
                              TempParamLists.data()).get();
  } else {
    // The "template<>" header is extraneous.
    Diag(TemplateParams->getTemplateLoc(), diag::err_template_tag_noparams)
      << TypeWithKeyword::getTagTypeKindName(Kind) << Name;
    IsMemberSpecialization = true;
  }
}

if (Invalid) return nullptr;

bool isAllExplicitSpecializations = true;
for (unsigned I = TempParamLists.size(); I-- > 0; ) {
  if (TempParamLists[I]->size()) {
    isAllExplicitSpecializations = false;
    break;
  }
}

// FIXME: don't ignore attributes.

// If it's explicit specializations all the way down, just forget
// about the template header and build an appropriate non-templated
// friend.  TODO: for source fidelity, remember the headers.
if (isAllExplicitSpecializations) {
  if (SS.isEmpty()) {
    bool Owned = false;
    bool IsDependent = false;
    return ActOnTag(S, TagSpec, TUK_Friend, TagLoc, SS, Name, NameLoc,
                    Attr, AS_public,
                    /*ModulePrivateLoc=*/SourceLocation(),
                    MultiTemplateParamsArg(), Owned, IsDependent,
                    /*ScopedEnumKWLoc=*/SourceLocation(),
                    /*ScopedEnumUsesClassTag=*/false,
                    /*UnderlyingType=*/TypeResult(),
                    /*IsTypeSpecifier=*/false,
                    /*IsTemplateParamOrArg=*/false);
  }

  NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
  ElaboratedTypeKeyword Keyword
    = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
  QualType T = CheckTypenameType(Keyword, TagLoc, QualifierLoc,
                                 *Name, NameLoc);
  if (T.isNull())
    return nullptr;

  TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
  if (isa<DependentNameType>(T)) {
    DependentNameTypeLoc TL =
        TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
    TL.setElaboratedKeywordLoc(TagLoc);
    TL.setQualifierLoc(QualifierLoc);
    TL.setNameLoc(NameLoc);
  } else {
    ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
    TL.setElaboratedKeywordLoc(TagLoc);
    TL.setQualifierLoc(QualifierLoc);
    TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(NameLoc);
  }

  FriendDecl *Friend = FriendDecl::Create(Context, CurContext, NameLoc,
                                          TSI, FriendLoc, TempParamLists);
  Friend->setAccess(AS_public);
  CurContext->addDecl(Friend);
  return Friend;
}

assert(SS.isNotEmpty() && "valid templated tag with no SS and no direct?")((void)0);



// Handle the case of a templated-scope friend class.  e.g.
//   template <class T> class A<T>::B;
// FIXME: we don't support these right now.
Diag(NameLoc, diag::warn_template_qualified_friend_unsupported)
  << SS.getScopeRep() << SS.getRange() << cast<CXXRecordDecl>(CurContext);
ElaboratedTypeKeyword ETK = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
QualType T = Context.getDependentNameType(ETK, SS.getScopeRep(), Name);
TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
TL.setElaboratedKeywordLoc(TagLoc);
TL.setQualifierLoc(SS.getWithLocInContext(Context));
TL.setNameLoc(NameLoc);

FriendDecl *Friend = FriendDecl::Create(Context, CurContext, NameLoc,
                                        TSI, FriendLoc, TempParamLists);
Friend->setAccess(AS_public);
Friend->setUnsupportedFriend(true);
CurContext->addDecl(Friend);
return Friend;
16578}

16580/// Handle a friend type declaration.  This works in tandem with
16581/// ActOnTag.
16582///
16583/// Notes on friend class templates:
16584///
16585/// We generally treat friend class declarations as if they were
16586/// declaring a class.  So, for example, the elaborated type specifier
16587/// in a friend declaration is required to obey the restrictions of a
16588/// class-head (i.e. no typedefs in the scope chain), template
16589/// parameters are required to match up with simple template-ids, &c.
16590/// However, unlike when declaring a template specialization, it's
16591/// okay to refer to a template specialization without an empty
16592/// template parameter declaration, e.g.
16593///   friend class A<T>::B<unsigned>;
16594/// We permit this as a special case; if there are any template
16595/// parameters present at all, require proper matching, i.e.
16596///   template <> template \<class T> friend class A<int>::B;
16597Decl *Sema::ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
                              MultiTemplateParamsArg TempParams) {
SourceLocation Loc = DS.getBeginLoc();

assert(DS.isFriendSpecified())((void)0);
assert(DS.getStorageClassSpec() == DeclSpec::SCS_unspecified)((void)0);

// C++ [class.friend]p3:
// A friend declaration that does not declare a function shall have one of
// the following forms:
//     friend elaborated-type-specifier ;
//     friend simple-type-specifier ;
//     friend typename-specifier ;
//
// Any declaration with a type qualifier does not have that form. (It's
// legal to specify a qualified type as a friend, you just can't write the
// keywords.)
if (DS.getTypeQualifiers()) {
  if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
    Diag(DS.getConstSpecLoc(), diag::err_friend_decl_spec) << "const";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
    Diag(DS.getVolatileSpecLoc(), diag::err_friend_decl_spec) << "volatile";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
    Diag(DS.getRestrictSpecLoc(), diag::err_friend_decl_spec) << "restrict";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
    Diag(DS.getAtomicSpecLoc(), diag::err_friend_decl_spec) << "_Atomic";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_unaligned)
    Diag(DS.getUnalignedSpecLoc(), diag::err_friend_decl_spec) << "__unaligned";
}

// Try to convert the decl specifier to a type.  This works for
// friend templates because ActOnTag never produces a ClassTemplateDecl
// for a TUK_Friend.
Declarator TheDeclarator(DS, DeclaratorContext::Member);
TypeSourceInfo *TSI = GetTypeForDeclarator(TheDeclarator, S);
QualType T = TSI->getType();
if (TheDeclarator.isInvalidType())
  return nullptr;

if (DiagnoseUnexpandedParameterPack(Loc, TSI, UPPC_FriendDeclaration))
  return nullptr;

// This is definitely an error in C++98.  It's probably meant to
// be forbidden in C++0x, too, but the specification is just
// poorly written.
//
// The problem is with declarations like the following:
//   template <T> friend A<T>::foo;
// where deciding whether a class C is a friend or not now hinges
// on whether there exists an instantiation of A that causes
// 'foo' to equal C.  There are restrictions on class-heads
// (which we declare (by fiat) elaborated friend declarations to
// be) that makes this tractable.
//
// FIXME: handle "template <> friend class A<T>;", which
// is possibly well-formed?  Who even knows?
if (TempParams.size() && !T->isElaboratedTypeSpecifier()) {
  Diag(Loc, diag::err_tagless_friend_type_template)
    << DS.getSourceRange();
  return nullptr;
}

// C++98 [class.friend]p1: A friend of a class is a function
//   or class that is not a member of the class . . .
// This is fixed in DR77, which just barely didn't make the C++03
// deadline.  It's also a very silly restriction that seriously
// affects inner classes and which nobody else seems to implement;
// thus we never diagnose it, not even in -pedantic.
//
// But note that we could warn about it: it's always useless to
// friend one of your own members (it's not, however, worthless to
// friend a member of an arbitrary specialization of your template).

Decl *D;
if (!TempParams.empty())
  D = FriendTemplateDecl::Create(Context, CurContext, Loc,
                                 TempParams,
                                 TSI,
                                 DS.getFriendSpecLoc());
else
  D = CheckFriendTypeDecl(Loc, DS.getFriendSpecLoc(), TSI);

if (!D)
  return nullptr;

D->setAccess(AS_public);
CurContext->addDecl(D);

return D;
16686}

16688NamedDecl *Sema::ActOnFriendFunctionDecl(Scope *S, Declarator &D,
                                      MultiTemplateParamsArg TemplateParams) {
const DeclSpec &DS = D.getDeclSpec();

assert(DS.isFriendSpecified())((void)0);
assert(DS.getStorageClassSpec() == DeclSpec::SCS_unspecified)((void)0);

SourceLocation Loc = D.getIdentifierLoc();
TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);

// C++ [class.friend]p1
//   A friend of a class is a function or class....
// Note that this sees through typedefs, which is intended.
// It *doesn't* see through dependent types, which is correct
// according to [temp.arg.type]p3:
//   If a declaration acquires a function type through a
//   type dependent on a template-parameter and this causes
//   a declaration that does not use the syntactic form of a
//   function declarator to have a function type, the program
//   is ill-formed.
if (!TInfo->getType()->isFunctionType()) {
  Diag(Loc, diag::err_unexpected_friend);

  // It might be worthwhile to try to recover by creating an
  // appropriate declaration.
  return nullptr;
}

// C++ [namespace.memdef]p3
//  - If a friend declaration in a non-local class first declares a
//    class or function, the friend class or function is a member
//    of the innermost enclosing namespace.
//  - The name of the friend is not found by simple name lookup
//    until a matching declaration is provided in that namespace
//    scope (either before or after the class declaration granting
//    friendship).
//  - If a friend function is called, its name may be found by the
//    name lookup that considers functions from namespaces and
//    classes associated with the types of the function arguments.
//  - When looking for a prior declaration of a class or a function
//    declared as a friend, scopes outside the innermost enclosing
//    namespace scope are not considered.

CXXScopeSpec &SS = D.getCXXScopeSpec();
DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
assert(NameInfo.getName())((void)0);

// Check for unexpanded parameter packs.
if (DiagnoseUnexpandedParameterPack(Loc, TInfo, UPPC_FriendDeclaration) ||
    DiagnoseUnexpandedParameterPack(NameInfo, UPPC_FriendDeclaration) ||
    DiagnoseUnexpandedParameterPack(SS, UPPC_FriendDeclaration))
  return nullptr;

// The context we found the declaration in, or in which we should
// create the declaration.
DeclContext *DC;
Scope *DCScope = S;
LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
                      ForExternalRedeclaration);

// There are five cases here.
//   - There's no scope specifier and we're in a local class. Only look
//     for functions declared in the immediately-enclosing block scope.
// We recover from invalid scope qualifiers as if they just weren't there.
FunctionDecl *FunctionContainingLocalClass = nullptr;
if ((SS.isInvalid() || !SS.isSet()) &&
    (FunctionContainingLocalClass =
         cast<CXXRecordDecl>(CurContext)->isLocalClass())) {
  // C++11 [class.friend]p11:
  //   If a friend declaration appears in a local class and the name
  //   specified is an unqualified name, a prior declaration is
  //   looked up without considering scopes that are outside the
  //   innermost enclosing non-class scope. For a friend function
  //   declaration, if there is no prior declaration, the program is
  //   ill-formed.

  // Find the innermost enclosing non-class scope. This is the block
  // scope containing the local class definition (or for a nested class,
  // the outer local class).
  DCScope = S->getFnParent();

  // Look up the function name in the scope.
  Previous.clear(LookupLocalFriendName);
  LookupName(Previous, S, /*AllowBuiltinCreation*/false);

  if (!Previous.empty()) {
    // All possible previous declarations must have the same context:
    // either they were declared at block scope or they are members of
    // one of the enclosing local classes.
    DC = Previous.getRepresentativeDecl()->getDeclContext();
  } else {
    // This is ill-formed, but provide the context that we would have
    // declared the function in, if we were permitted to, for error recovery.
    DC = FunctionContainingLocalClass;
  }
  adjustContextForLocalExternDecl(DC);

  // C++ [class.friend]p6:
  //   A function can be defined in a friend declaration of a class if and
  //   only if the class is a non-local class (9.8), the function name is
  //   unqualified, and the function has namespace scope.
  if (D.isFunctionDefinition()) {
    Diag(NameInfo.getBeginLoc(), diag::err_friend_def_in_local_class);
  }

//   - There's no scope specifier, in which case we just go to the
//     appropriate scope and look for a function or function template
//     there as appropriate.
} else if (SS.isInvalid() || !SS.isSet()) {
  // C++11 [namespace.memdef]p3:
  //   If the name in a friend declaration is neither qualified nor
  //   a template-id and the declaration is a function or an
  //   elaborated-type-specifier, the lookup to determine whether
  //   the entity has been previously declared shall not consider
  //   any scopes outside the innermost enclosing namespace.
  bool isTemplateId =
      D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId;

  // Find the appropriate context according to the above.
  DC = CurContext;

  // Skip class contexts.  If someone can cite chapter and verse
  // for this behavior, that would be nice --- it's what GCC and
  // EDG do, and it seems like a reasonable intent, but the spec
  // really only says that checks for unqualified existing
  // declarations should stop at the nearest enclosing namespace,
  // not that they should only consider the nearest enclosing
  // namespace.
  while (DC->isRecord())
    DC = DC->getParent();

  DeclContext *LookupDC = DC;
  while (LookupDC->isTransparentContext())
    LookupDC = LookupDC->getParent();

  while (true) {
    LookupQualifiedName(Previous, LookupDC);

    if (!Previous.empty()) {
      DC = LookupDC;
      break;
    }

    if (isTemplateId) {
      if (isa<TranslationUnitDecl>(LookupDC)) break;
    } else {
      if (LookupDC->isFileContext()) break;
    }
    LookupDC = LookupDC->getParent();
  }

  DCScope = getScopeForDeclContext(S, DC);

//   - There's a non-dependent scope specifier, in which case we
//     compute it and do a previous lookup there for a function
//     or function template.
} else if (!SS.getScopeRep()->isDependent()) {
  DC = computeDeclContext(SS);
  if (!DC) return nullptr;

  if (RequireCompleteDeclContext(SS, DC)) return nullptr;

  LookupQualifiedName(Previous, DC);

  // C++ [class.friend]p1: A friend of a class is a function or
  //   class that is not a member of the class . . .
  if (DC->Equals(CurContext))
    Diag(DS.getFriendSpecLoc(),
         getLangOpts().CPlusPlus11 ?
           diag::warn_cxx98_compat_friend_is_member :
           diag::err_friend_is_member);

  if (D.isFunctionDefinition()) {
    // C++ [class.friend]p6:
    //   A function can be defined in a friend declaration of a class if and
    //   only if the class is a non-local class (9.8), the function name is
    //   unqualified, and the function has namespace scope.
    //
    // FIXME: We should only do this if the scope specifier names the
    // innermost enclosing namespace; otherwise the fixit changes the
    // meaning of the code.
    SemaDiagnosticBuilder DB
      = Diag(SS.getRange().getBegin(), diag::err_qualified_friend_def);

    DB << SS.getScopeRep();
    if (DC->isFileContext())
      DB << FixItHint::CreateRemoval(SS.getRange());
    SS.clear();
  }

//   - There's a scope specifier that does not match any template
//     parameter lists, in which case we use some arbitrary context,
//     create a method or method template, and wait for instantiation.
//   - There's a scope specifier that does match some template
//     parameter lists, which we don't handle right now.
} else {
  if (D.isFunctionDefinition()) {
    // C++ [class.friend]p6:
    //   A function can be defined in a friend declaration of a class if and
    //   only if the class is a non-local class (9.8), the function name is
    //   unqualified, and the function has namespace scope.
    Diag(SS.getRange().getBegin(), diag::err_qualified_friend_def)
      << SS.getScopeRep();
  }

  DC = CurContext;
  assert(isa<CXXRecordDecl>(DC) && "friend declaration not in class?")((void)0);
}

if (!DC->isRecord()) {
  int DiagArg = -1;
  switch (D.getName().getKind()) {
  case UnqualifiedIdKind::IK_ConstructorTemplateId:
  case UnqualifiedIdKind::IK_ConstructorName:
    DiagArg = 0;
    break;
  case UnqualifiedIdKind::IK_DestructorName:
    DiagArg = 1;
    break;
  case UnqualifiedIdKind::IK_ConversionFunctionId:
    DiagArg = 2;
    break;
  case UnqualifiedIdKind::IK_DeductionGuideName:
    DiagArg = 3;
    break;
  case UnqualifiedIdKind::IK_Identifier:
  case UnqualifiedIdKind::IK_ImplicitSelfParam:
  case UnqualifiedIdKind::IK_LiteralOperatorId:
  case UnqualifiedIdKind::IK_OperatorFunctionId:
  case UnqualifiedIdKind::IK_TemplateId:
    break;
  }
  // This implies that it has to be an operator or function.
  if (DiagArg >= 0) {
    Diag(Loc, diag::err_introducing_special_friend) << DiagArg;
    return nullptr;
  }
}

// FIXME: This is an egregious hack to cope with cases where the scope stack
// does not contain the declaration context, i.e., in an out-of-line
// definition of a class.
Scope FakeDCScope(S, Scope::DeclScope, Diags);
if (!DCScope) {
  FakeDCScope.setEntity(DC);
  DCScope = &FakeDCScope;
}

bool AddToScope = true;
NamedDecl *ND = ActOnFunctionDeclarator(DCScope, D, DC, TInfo, Previous,
                                        TemplateParams, AddToScope);
if (!ND) return nullptr;

assert(ND->getLexicalDeclContext() == CurContext)((void)0);

// If we performed typo correction, we might have added a scope specifier
// and changed the decl context.
DC = ND->getDeclContext();

// Add the function declaration to the appropriate lookup tables,
// adjusting the redeclarations list as necessary.  We don't
// want to do this yet if the friending class is dependent.
//
// Also update the scope-based lookup if the target context's
// lookup context is in lexical scope.
if (!CurContext->isDependentContext()) {
  DC = DC->getRedeclContext();
  DC->makeDeclVisibleInContext(ND);
  if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
    PushOnScopeChains(ND, EnclosingScope, /*AddToContext=*/ false);
}

FriendDecl *FrD = FriendDecl::Create(Context, CurContext,
                                     D.getIdentifierLoc(), ND,
                                     DS.getFriendSpecLoc());
FrD->setAccess(AS_public);
CurContext->addDecl(FrD);

if (ND->isInvalidDecl()) {
  FrD->setInvalidDecl();
} else {
  if (DC->isRecord()) CheckFriendAccess(ND);

  FunctionDecl *FD;
  if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
    FD = FTD->getTemplatedDecl();
  else
    FD = cast<FunctionDecl>(ND);

  // C++11 [dcl.fct.default]p4: If a friend declaration specifies a
  // default argument expression, that declaration shall be a definition
  // and shall be the only declaration of the function or function
  // template in the translation unit.
  if (functionDeclHasDefaultArgument(FD)) {
    // We can't look at FD->getPreviousDecl() because it may not have been set
    // if we're in a dependent context. If the function is known to be a
    // redeclaration, we will have narrowed Previous down to the right decl.
    if (D.isRedeclaration()) {
      Diag(FD->getLocation(), diag::err_friend_decl_with_def_arg_redeclared);
      Diag(Previous.getRepresentativeDecl()->getLocation(),
           diag::note_previous_declaration);
    } else if (!D.isFunctionDefinition())
      Diag(FD->getLocation(), diag::err_friend_decl_with_def_arg_must_be_def);
  }

  // Mark templated-scope function declarations as unsupported.
  if (FD->getNumTemplateParameterLists() && SS.isValid()) {
    Diag(FD->getLocation(), diag::warn_template_qualified_friend_unsupported)
      << SS.getScopeRep() << SS.getRange()
      << cast<CXXRecordDecl>(CurContext);
    FrD->setUnsupportedFriend(true);
  }
}

warnOnReservedIdentifier(ND);

return ND;
17005}

17007void Sema::SetDeclDeleted(Decl *Dcl, SourceLocation DelLoc) {
AdjustDeclIfTemplate(Dcl);

FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(Dcl);
if (!Fn) {
  Diag(DelLoc, diag::err_deleted_non_function);
  return;
}

// Deleted function does not have a body.
Fn->setWillHaveBody(false);

if (const FunctionDecl *Prev = Fn->getPreviousDecl()) {
  // Don't consider the implicit declaration we generate for explicit
  // specializations. FIXME: Do not generate these implicit declarations.
  if ((Prev->getTemplateSpecializationKind() != TSK_ExplicitSpecialization ||
       Prev->getPreviousDecl()) &&
      !Prev->isDefined()) {
    Diag(DelLoc, diag::err_deleted_decl_not_first);
    Diag(Prev->getLocation().isInvalid() ? DelLoc : Prev->getLocation(),
         Prev->isImplicit() ? diag::note_previous_implicit_declaration
                            : diag::note_previous_declaration);
    // We can't recover from this; the declaration might have already
    // been used.
    Fn->setInvalidDecl();
    return;
  }

  // To maintain the invariant that functions are only deleted on their first
  // declaration, mark the implicitly-instantiated declaration of the
  // explicitly-specialized function as deleted instead of marking the
  // instantiated redeclaration.
  Fn = Fn->getCanonicalDecl();
}

// dllimport/dllexport cannot be deleted.
if (const InheritableAttr *DLLAttr = getDLLAttr(Fn)) {
  Diag(Fn->getLocation(), diag::err_attribute_dll_deleted) << DLLAttr;
  Fn->setInvalidDecl();
}

// C++11 [basic.start.main]p3:
//   A program that defines main as deleted [...] is ill-formed.
if (Fn->isMain())
  Diag(DelLoc, diag::err_deleted_main);

// C++11 [dcl.fct.def.delete]p4:
//  A deleted function is implicitly inline.
Fn->setImplicitlyInline();
Fn->setDeletedAsWritten();
17057}

17059void Sema::SetDeclDefaulted(Decl *Dcl, SourceLocation DefaultLoc) {
if (!Dcl || Dcl->isInvalidDecl())
  return;

auto *FD = dyn_cast<FunctionDecl>(Dcl);
if (!FD) {
  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(Dcl)) {
    if (getDefaultedFunctionKind(FTD->getTemplatedDecl()).isComparison()) {
      Diag(DefaultLoc, diag::err_defaulted_comparison_template);
      return;
    }
  }

  Diag(DefaultLoc, diag::err_default_special_members)
      << getLangOpts().CPlusPlus20;
  return;
}

// Reject if this can't possibly be a defaultable function.
DefaultedFunctionKind DefKind = getDefaultedFunctionKind(FD);
if (!DefKind &&
    // A dependent function that doesn't locally look defaultable can
    // still instantiate to a defaultable function if it's a constructor
    // or assignment operator.
    (!FD->isDependentContext() ||
     (!isa<CXXConstructorDecl>(FD) &&
      FD->getDeclName().getCXXOverloadedOperator() != OO_Equal))) {
  Diag(DefaultLoc, diag::err_default_special_members)
      << getLangOpts().CPlusPlus20;
  return;
}

if (DefKind.isComparison() &&
    !isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
  Diag(FD->getLocation(), diag::err_defaulted_comparison_out_of_class)
      << (int)DefKind.asComparison();
  return;
}

// Issue compatibility warning. We already warned if the operator is
// 'operator<=>' when parsing the '<=>' token.
if (DefKind.isComparison() &&
    DefKind.asComparison() != DefaultedComparisonKind::ThreeWay) {
  Diag(DefaultLoc, getLangOpts().CPlusPlus20
                       ? diag::warn_cxx17_compat_defaulted_comparison
                       : diag::ext_defaulted_comparison);
}

FD->setDefaulted();
FD->setExplicitlyDefaulted();

// Defer checking functions that are defaulted in a dependent context.
if (FD->isDependentContext())
  return;

// Unset that we will have a body for this function. We might not,
// if it turns out to be trivial, and we don't need this marking now
// that we've marked it as defaulted.
FD->setWillHaveBody(false);

// If this definition appears within the record, do the checking when
// the record is complete. This is always the case for a defaulted
// comparison.
if (DefKind.isComparison())
  return;
auto *MD = cast<CXXMethodDecl>(FD);

const FunctionDecl *Primary = FD;
if (const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern())
  // Ask the template instantiation pattern that actually had the
  // '= default' on it.
  Primary = Pattern;

// If the method was defaulted on its first declaration, we will have
// already performed the checking in CheckCompletedCXXClass. Such a
// declaration doesn't trigger an implicit definition.
if (Primary->getCanonicalDecl()->isDefaulted())
  return;

// FIXME: Once we support defining comparisons out of class, check for a
// defaulted comparison here.
if (CheckExplicitlyDefaultedSpecialMember(MD, DefKind.asSpecialMember()))
  MD->setInvalidDecl();
else
  DefineDefaultedFunction(*this, MD, DefaultLoc);
17144}

17146static void SearchForReturnInStmt(Sema &Self, Stmt *S) {
for (Stmt *SubStmt : S->children()) {
  if (!SubStmt)
    continue;
  if (isa<ReturnStmt>(SubStmt))
    Self.Diag(SubStmt->getBeginLoc(),
              diag::err_return_in_constructor_handler);
  if (!isa<Expr>(SubStmt))
    SearchForReturnInStmt(Self, SubStmt);
}
17156}

17158void Sema::DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock) {
for (unsigned I = 0, E = TryBlock->getNumHandlers(); I != E; ++I) {
  CXXCatchStmt *Handler = TryBlock->getHandler(I);
  SearchForReturnInStmt(*this, Handler);
}
17163}

17165bool Sema::CheckOverridingFunctionAttributes(const CXXMethodDecl *New,
                                           const CXXMethodDecl *Old) {
const auto *NewFT = New->getType()->castAs<FunctionProtoType>();
const auto *OldFT = Old->getType()->castAs<FunctionProtoType>();

if (OldFT->hasExtParameterInfos()) {
  for (unsigned I = 0, E = OldFT->getNumParams(); I != E; ++I)
    // A parameter of the overriding method should be annotated with noescape
    // if the corresponding parameter of the overridden method is annotated.
    if (OldFT->getExtParameterInfo(I).isNoEscape() &&
        !NewFT->getExtParameterInfo(I).isNoEscape()) {
      Diag(New->getParamDecl(I)->getLocation(),
           diag::warn_overriding_method_missing_noescape);
      Diag(Old->getParamDecl(I)->getLocation(),
           diag::note_overridden_marked_noescape);
    }
}

// Virtual overrides must have the same code_seg.
const auto *OldCSA = Old->getAttr<CodeSegAttr>();
const auto *NewCSA = New->getAttr<CodeSegAttr>();
if ((NewCSA || OldCSA) &&
    (!OldCSA || !NewCSA || NewCSA->getName() != OldCSA->getName())) {
  Diag(New->getLocation(), diag::err_mismatched_code_seg_override);
  Diag(Old->getLocation(), diag::note_previous_declaration);
  return true;
}

CallingConv NewCC = NewFT->getCallConv(), OldCC = OldFT->getCallConv();

// If the calling conventions match, everything is fine
if (NewCC == OldCC)
  return false;

// If the calling conventions mismatch because the new function is static,
// suppress the calling convention mismatch error; the error about static
// function override (err_static_overrides_virtual from
// Sema::CheckFunctionDeclaration) is more clear.
if (New->getStorageClass() == SC_Static)
  return false;

Diag(New->getLocation(),
     diag::err_conflicting_overriding_cc_attributes)
  << New->getDeclName() << New->getType() << Old->getType();
Diag(Old->getLocation(), diag::note_overridden_virtual_function);
return true;
17211}

17213bool Sema::CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
                                           const CXXMethodDecl *Old) {
QualType NewTy = New->getType()->castAs<FunctionType>()->getReturnType();
QualType OldTy = Old->getType()->castAs<FunctionType>()->getReturnType();

if (Context.hasSameType(NewTy, OldTy) ||
    NewTy->isDependentType() || OldTy->isDependentType())
  return false;

// Check if the return types are covariant
QualType NewClassTy, OldClassTy;

/// Both types must be pointers or references to classes.
if (const PointerType *NewPT = NewTy->getAs<PointerType>()) {
  if (const PointerType *OldPT = OldTy->getAs<PointerType>()) {
    NewClassTy = NewPT->getPointeeType();
    OldClassTy = OldPT->getPointeeType();
  }
} else if (const ReferenceType *NewRT = NewTy->getAs<ReferenceType>()) {
  if (const ReferenceType *OldRT = OldTy->getAs<ReferenceType>()) {
    if (NewRT->getTypeClass() == OldRT->getTypeClass()) {
      NewClassTy = NewRT->getPointeeType();
      OldClassTy = OldRT->getPointeeType();
    }
  }
}

// The return types aren't either both pointers or references to a class type.
if (NewClassTy.isNull()) {
  Diag(New->getLocation(),
       diag::err_different_return_type_for_overriding_virtual_function)
      << New->getDeclName() << NewTy << OldTy
      << New->getReturnTypeSourceRange();
  Diag(Old->getLocation(), diag::note_overridden_virtual_function)
      << Old->getReturnTypeSourceRange();

  return true;
}

if (!Context.hasSameUnqualifiedType(NewClassTy, OldClassTy)) {
  // C++14 [class.virtual]p8:
  //   If the class type in the covariant return type of D::f differs from
  //   that of B::f, the class type in the return type of D::f shall be
  //   complete at the point of declaration of D::f or shall be the class
  //   type D.
  if (const RecordType *RT = NewClassTy->getAs<RecordType>()) {
    if (!RT->isBeingDefined() &&
        RequireCompleteType(New->getLocation(), NewClassTy,
                            diag::err_covariant_return_incomplete,
                            New->getDeclName()))
      return true;
  }

  // Check if the new class derives from the old class.
  if (!IsDerivedFrom(New->getLocation(), NewClassTy, OldClassTy)) {
    Diag(New->getLocation(), diag::err_covariant_return_not_derived)
        << New->getDeclName() << NewTy << OldTy
        << New->getReturnTypeSourceRange();
    Diag(Old->getLocation(), diag::note_overridden_virtual_function)
        << Old->getReturnTypeSourceRange();
    return true;
  }

  // Check if we the conversion from derived to base is valid.
  if (CheckDerivedToBaseConversion(
          NewClassTy, OldClassTy,
          diag::err_covariant_return_inaccessible_base,
          diag::err_covariant_return_ambiguous_derived_to_base_conv,
          New->getLocation(), New->getReturnTypeSourceRange(),
          New->getDeclName(), nullptr)) {
    // FIXME: this note won't trigger for delayed access control
    // diagnostics, and it's impossible to get an undelayed error
    // here from access control during the original parse because
    // the ParsingDeclSpec/ParsingDeclarator are still in scope.
    Diag(Old->getLocation(), diag::note_overridden_virtual_function)
        << Old->getReturnTypeSourceRange();
    return true;
  }
}

// The qualifiers of the return types must be the same.
if (NewTy.getLocalCVRQualifiers() != OldTy.getLocalCVRQualifiers()) {
  Diag(New->getLocation(),
       diag::err_covariant_return_type_different_qualifications)
      << New->getDeclName() << NewTy << OldTy
      << New->getReturnTypeSourceRange();
  Diag(Old->getLocation(), diag::note_overridden_virtual_function)
      << Old->getReturnTypeSourceRange();
  return true;
}


// The new class type must have the same or less qualifiers as the old type.
if (NewClassTy.isMoreQualifiedThan(OldClassTy)) {
  Diag(New->getLocation(),
       diag::err_covariant_return_type_class_type_more_qualified)
      << New->getDeclName() << NewTy << OldTy
      << New->getReturnTypeSourceRange();
  Diag(Old->getLocation(), diag::note_overridden_virtual_function)
      << Old->getReturnTypeSourceRange();
  return true;
}

return false;
17317}

17319/// Mark the given method pure.
17320///
17321/// \param Method the method to be marked pure.
17322///
17323/// \param InitRange the source range that covers the "0" initializer.
17324bool Sema::CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange) {
SourceLocation EndLoc = InitRange.getEnd();
if (EndLoc.isValid())
  Method->setRangeEnd(EndLoc);

if (Method->isVirtual() || Method->getParent()->isDependentContext()) {
  Method->setPure();
  return false;
}

if (!Method->isInvalidDecl())
  Diag(Method->getLocation(), diag::err_non_virtual_pure)
    << Method->getDeclName() << InitRange;
return true;
17338}

17340void Sema::ActOnPureSpecifier(Decl *D, SourceLocation ZeroLoc) {
if (D->getFriendObjectKind())
  Diag(D->getLocation(), diag::err_pure_friend);
else if (auto *M = dyn_cast<CXXMethodDecl>(D))
  CheckPureMethod(M, ZeroLoc);
else
  Diag(D->getLocation(), diag::err_illegal_initializer);
17347}

17349/// Determine whether the given declaration is a global variable or
17350/// static data member.
17351static bool isNonlocalVariable(const Decl *D) {
if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(D))
  return Var->hasGlobalStorage();

return false;
17356}

17358/// Invoked when we are about to parse an initializer for the declaration
17359/// 'Dcl'.
17360///
17361/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
17362/// static data member of class X, names should be looked up in the scope of
17363/// class X. If the declaration had a scope specifier, a scope will have
17364/// been created and passed in for this purpose. Otherwise, S will be null.
17365void Sema::ActOnCXXEnterDeclInitializer(Scope *S, Decl *D) {
// If there is no declaration, there was an error parsing it.
if (!D || D->isInvalidDecl())
  return;

// We will always have a nested name specifier here, but this declaration
// might not be out of line if the specifier names the current namespace:
//   extern int n;
//   int ::n = 0;
if (S && D->isOutOfLine())
  EnterDeclaratorContext(S, D->getDeclContext());

// If we are parsing the initializer for a static data member, push a
// new expression evaluation context that is associated with this static
// data member.
if (isNonlocalVariable(D))
  PushExpressionEvaluationContext(
      ExpressionEvaluationContext::PotentiallyEvaluated, D);
17383}

17385/// Invoked after we are finished parsing an initializer for the declaration D.
17386void Sema::ActOnCXXExitDeclInitializer(Scope *S, Decl *D) {
// If there is no declaration, there was an error parsing it.
if (!D || D->isInvalidDecl())
  return;

if (isNonlocalVariable(D))
  PopExpressionEvaluationContext();

if (S && D->isOutOfLine())
  ExitDeclaratorContext(S);
17396}

17398/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
17399/// C++ if/switch/while/for statement.
17400/// e.g: "if (int x = f()) {...}"
17401DeclResult Sema::ActOnCXXConditionDeclaration(Scope *S, Declarator &D) {
// C++ 6.4p2:
// The declarator shall not specify a function or an array.
// The type-specifier-seq shall not contain typedef and shall not declare a
// new class or enumeration.
assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&((void)0)
       "Parser allowed 'typedef' as storage class of condition decl.")((void)0);

Decl *Dcl = ActOnDeclarator(S, D);
if (!Dcl)
  return true;

if (isa<FunctionDecl>(Dcl)) { // The declarator shall not specify a function.
  Diag(Dcl->getLocation(), diag::err_invalid_use_of_function_type)
    << D.getSourceRange();
  return true;
}

return Dcl;
17420}

17422void Sema::LoadExternalVTableUses() {
if (!ExternalSource)
  return;

SmallVector<ExternalVTableUse, 4> VTables;
ExternalSource->ReadUsedVTables(VTables);
SmallVector<VTableUse, 4> NewUses;
for (unsigned I = 0, N = VTables.size(); I != N; ++I) {
  llvm::DenseMap<CXXRecordDecl *, bool>::iterator Pos
    = VTablesUsed.find(VTables[I].Record);
  // Even if a definition wasn't required before, it may be required now.
  if (Pos != VTablesUsed.end()) {
    if (!Pos->second && VTables[I].DefinitionRequired)
      Pos->second = true;
    continue;
  }

  VTablesUsed[VTables[I].Record] = VTables[I].DefinitionRequired;
  NewUses.push_back(VTableUse(VTables[I].Record, VTables[I].Location));
}

VTableUses.insert(VTableUses.begin(), NewUses.begin(), NewUses.end());
17444}

17446void Sema::MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
                        bool DefinitionRequired) {
// Ignore any vtable uses in unevaluated operands or for classes that do
// not have a vtable.
if (!Class->isDynamicClass() || Class->isDependentContext() ||
    CurContext->isDependentContext() || isUnevaluatedContext())
  return;
// Do not mark as used if compiling for the device outside of the target
// region.
if (TUKind != TU_Prefix && LangOpts.OpenMP && LangOpts.OpenMPIsDevice &&
    !isInOpenMPDeclareTargetContext() &&
    !isInOpenMPTargetExecutionDirective()) {
  if (!DefinitionRequired)
    MarkVirtualMembersReferenced(Loc, Class);
  return;
}

// Try to insert this class into the map.
LoadExternalVTableUses();
Class = Class->getCanonicalDecl();
std::pair<llvm::DenseMap<CXXRecordDecl *, bool>::iterator, bool>
  Pos = VTablesUsed.insert(std::make_pair(Class, DefinitionRequired));
if (!Pos.second) {
  // If we already had an entry, check to see if we are promoting this vtable
  // to require a definition. If so, we need to reappend to the VTableUses
  // list, since we may have already processed the first entry.
  if (DefinitionRequired && !Pos.first->second) {
    Pos.first->second = true;
  } else {
    // Otherwise, we can early exit.
    return;
  }
} else {
  // The Microsoft ABI requires that we perform the destructor body
  // checks (i.e. operator delete() lookup) when the vtable is marked used, as
  // the deleting destructor is emitted with the vtable, not with the
  // destructor definition as in the Itanium ABI.
  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
    CXXDestructorDecl *DD = Class->getDestructor();
    if (DD && DD->isVirtual() && !DD->isDeleted()) {
      if (Class->hasUserDeclaredDestructor() && !DD->isDefined()) {
        // If this is an out-of-line declaration, marking it referenced will
        // not do anything. Manually call CheckDestructor to look up operator
        // delete().
        ContextRAII SavedContext(*this, DD);
        CheckDestructor(DD);
      } else {
        MarkFunctionReferenced(Loc, Class->getDestructor());
      }
    }
  }
}

// Local classes need to have their virtual members marked
// immediately. For all other classes, we mark their virtual members
// at the end of the translation unit.
if (Class->isLocalClass())
  MarkVirtualMembersReferenced(Loc, Class);
else
  VTableUses.push_back(std::make_pair(Class, Loc));
17506}

17508bool Sema::DefineUsedVTables() {
LoadExternalVTableUses();
if (VTableUses.empty())
  return false;

// Note: The VTableUses vector could grow as a result of marking
// the members of a class as "used", so we check the size each
// time through the loop and prefer indices (which are stable) to
// iterators (which are not).
bool DefinedAnything = false;
for (unsigned I = 0; I != VTableUses.size(); ++I) {
  CXXRecordDecl *Class = VTableUses[I].first->getDefinition();
  if (!Class)
    continue;
  TemplateSpecializationKind ClassTSK =
      Class->getTemplateSpecializationKind();

  SourceLocation Loc = VTableUses[I].second;

  bool DefineVTable = true;

  // If this class has a key function, but that key function is
  // defined in another translation unit, we don't need to emit the
  // vtable even though we're using it.
  const CXXMethodDecl *KeyFunction = Context.getCurrentKeyFunction(Class);
  if (KeyFunction && !KeyFunction->hasBody()) {
    // The key function is in another translation unit.
    DefineVTable = false;
    TemplateSpecializationKind TSK =
        KeyFunction->getTemplateSpecializationKind();
    assert(TSK != TSK_ExplicitInstantiationDefinition &&((void)0)
           TSK != TSK_ImplicitInstantiation &&((void)0)
           "Instantiations don't have key functions")((void)0);
    (void)TSK;
  } else if (!KeyFunction) {
    // If we have a class with no key function that is the subject
    // of an explicit instantiation declaration, suppress the
    // vtable; it will live with the explicit instantiation
    // definition.
    bool IsExplicitInstantiationDeclaration =
        ClassTSK == TSK_ExplicitInstantiationDeclaration;
    for (auto R : Class->redecls()) {
      TemplateSpecializationKind TSK
        = cast<CXXRecordDecl>(R)->getTemplateSpecializationKind();
      if (TSK == TSK_ExplicitInstantiationDeclaration)
        IsExplicitInstantiationDeclaration = true;
      else if (TSK == TSK_ExplicitInstantiationDefinition) {
        IsExplicitInstantiationDeclaration = false;
        break;
      }
    }

    if (IsExplicitInstantiationDeclaration)
      DefineVTable = false;
  }

  // The exception specifications for all virtual members may be needed even
  // if we are not providing an authoritative form of the vtable in this TU.
  // We may choose to emit it available_externally anyway.
  if (!DefineVTable) {
    MarkVirtualMemberExceptionSpecsNeeded(Loc, Class);
    continue;
  }

  // Mark all of the virtual members of this class as referenced, so
  // that we can build a vtable. Then, tell the AST consumer that a
  // vtable for this class is required.
  DefinedAnything = true;
  MarkVirtualMembersReferenced(Loc, Class);
  CXXRecordDecl *Canonical = Class->getCanonicalDecl();
  if (VTablesUsed[Canonical])
    Consumer.HandleVTable(Class);

  // Warn if we're emitting a weak vtable. The vtable will be weak if there is
  // no key function or the key function is inlined. Don't warn in C++ ABIs
  // that lack key functions, since the user won't be able to make one.
  if (Context.getTargetInfo().getCXXABI().hasKeyFunctions() &&
      Class->isExternallyVisible() && ClassTSK != TSK_ImplicitInstantiation) {
    const FunctionDecl *KeyFunctionDef = nullptr;
    if (!KeyFunction || (KeyFunction->hasBody(KeyFunctionDef) &&
                         KeyFunctionDef->isInlined())) {
      Diag(Class->getLocation(),
           ClassTSK == TSK_ExplicitInstantiationDefinition
               ? diag::warn_weak_template_vtable
               : diag::warn_weak_vtable)
          << Class;
    }
  }
}
VTableUses.clear();

return DefinedAnything;
17600}

17602void Sema::MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
                                               const CXXRecordDecl *RD) {
for (const auto *I : RD->methods())
  if (I->isVirtual() && !I->isPure())
    ResolveExceptionSpec(Loc, I->getType()->castAs<FunctionProtoType>());
17607}

17609void Sema::MarkVirtualMembersReferenced(SourceLocation Loc,
                                      const CXXRecordDecl *RD,
                                      bool ConstexprOnly) {
// Mark all functions which will appear in RD's vtable as used.
CXXFinalOverriderMap FinalOverriders;
RD->getFinalOverriders(FinalOverriders);
for (CXXFinalOverriderMap::const_iterator I = FinalOverriders.begin(),
                                          E = FinalOverriders.end();
     I != E; ++I) {
  for (OverridingMethods::const_iterator OI = I->second.begin(),
                                         OE = I->second.end();
       OI != OE; ++OI) {
    assert(OI->second.size() > 0 && "no final overrider")((void)0);
    CXXMethodDecl *Overrider = OI->second.front().Method;

    // C++ [basic.def.odr]p2:
    //   [...] A virtual member function is used if it is not pure. [...]
    if (!Overrider->isPure() && (!ConstexprOnly || Overrider->isConstexpr()))
      MarkFunctionReferenced(Loc, Overrider);
  }
}

// Only classes that have virtual bases need a VTT.
if (RD->getNumVBases() == 0)
  return;

for (const auto &I : RD->bases()) {
  const auto *Base =
      cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
  if (Base->getNumVBases() == 0)
    continue;
  MarkVirtualMembersReferenced(Loc, Base);
}
17642}

17644/// SetIvarInitializers - This routine builds initialization ASTs for the
17645/// Objective-C implementation whose ivars need be initialized.
17646void Sema::SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation) {
if (!getLangOpts().CPlusPlus)
  return;
if (ObjCInterfaceDecl *OID = ObjCImplementation->getClassInterface()) {
  SmallVector<ObjCIvarDecl*, 8> ivars;
  CollectIvarsToConstructOrDestruct(OID, ivars);
  if (ivars.empty())
    return;
  SmallVector<CXXCtorInitializer*, 32> AllToInit;
  for (unsigned i = 0; i < ivars.size(); i++) {
    FieldDecl *Field = ivars[i];
    if (Field->isInvalidDecl())
      continue;

    CXXCtorInitializer *Member;
    InitializedEntity InitEntity = InitializedEntity::InitializeMember(Field);
    InitializationKind InitKind =
      InitializationKind::CreateDefault(ObjCImplementation->getLocation());

    InitializationSequence InitSeq(*this, InitEntity, InitKind, None);
    ExprResult MemberInit =
      InitSeq.Perform(*this, InitEntity, InitKind, None);
    MemberInit = MaybeCreateExprWithCleanups(MemberInit);
    // Note, MemberInit could actually come back empty if no initialization
    // is required (e.g., because it would call a trivial default constructor)
    if (!MemberInit.get() || MemberInit.isInvalid())
      continue;

    Member =
      new (Context) CXXCtorInitializer(Context, Field, SourceLocation(),
                                       SourceLocation(),
                                       MemberInit.getAs<Expr>(),
                                       SourceLocation());
    AllToInit.push_back(Member);

    // Be sure that the destructor is accessible and is marked as referenced.
    if (const RecordType *RecordTy =
            Context.getBaseElementType(Field->getType())
                ->getAs<RecordType>()) {
      CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl());
      if (CXXDestructorDecl *Destructor = LookupDestructor(RD)) {
        MarkFunctionReferenced(Field->getLocation(), Destructor);
        CheckDestructorAccess(Field->getLocation(), Destructor,
                          PDiag(diag::err_access_dtor_ivar)
                            << Context.getBaseElementType(Field->getType()));
      }
    }
  }
  ObjCImplementation->setIvarInitializers(Context,
                                          AllToInit.data(), AllToInit.size());
}
17697}

17699static
17700void DelegatingCycleHelper(CXXConstructorDecl* Ctor,
                         llvm::SmallPtrSet<CXXConstructorDecl*, 4> &Valid,
                         llvm::SmallPtrSet<CXXConstructorDecl*, 4> &Invalid,
                         llvm::SmallPtrSet<CXXConstructorDecl*, 4> &Current,
                         Sema &S) {
if (Ctor->isInvalidDecl())
  return;

CXXConstructorDecl *Target = Ctor->getTargetConstructor();

// Target may not be determinable yet, for instance if this is a dependent
// call in an uninstantiated template.
if (Target) {
  const FunctionDecl *FNTarget = nullptr;
  (void)Target->hasBody(FNTarget);
  Target = const_cast<CXXConstructorDecl*>(
    cast_or_null<CXXConstructorDecl>(FNTarget));
}

CXXConstructorDecl *Canonical = Ctor->getCanonicalDecl(),
                   // Avoid dereferencing a null pointer here.
                   *TCanonical = Target? Target->getCanonicalDecl() : nullptr;

if (!Current.insert(Canonical).second)
  return;

// We know that beyond here, we aren't chaining into a cycle.
if (!Target || !Target->isDelegatingConstructor() ||
    Target->isInvalidDecl() || Valid.count(TCanonical)) {
  Valid.insert(Current.begin(), Current.end());
  Current.clear();
// We've hit a cycle.
} else if (TCanonical == Canonical || Invalid.count(TCanonical) ||
           Current.count(TCanonical)) {
  // If we haven't diagnosed this cycle yet, do so now.
  if (!Invalid.count(TCanonical)) {
    S.Diag((*Ctor->init_begin())->getSourceLocation(),
           diag::warn_delegating_ctor_cycle)
      << Ctor;

    // Don't add a note for a function delegating directly to itself.
    if (TCanonical != Canonical)
      S.Diag(Target->getLocation(), diag::note_it_delegates_to);

    CXXConstructorDecl *C = Target;
    while (C->getCanonicalDecl() != Canonical) {
      const FunctionDecl *FNTarget = nullptr;
      (void)C->getTargetConstructor()->hasBody(FNTarget);
      assert(FNTarget && "Ctor cycle through bodiless function")((void)0);

      C = const_cast<CXXConstructorDecl*>(
        cast<CXXConstructorDecl>(FNTarget));
      S.Diag(C->getLocation(), diag::note_which_delegates_to);
    }
  }

  Invalid.insert(Current.begin(), Current.end());
  Current.clear();
} else {
  DelegatingCycleHelper(Target, Valid, Invalid, Current, S);
}
17761}


17764void Sema::CheckDelegatingCtorCycles() {
llvm::SmallPtrSet<CXXConstructorDecl*, 4> Valid, Invalid, Current;

for (DelegatingCtorDeclsType::iterator
       I = DelegatingCtorDecls.begin(ExternalSource),
       E = DelegatingCtorDecls.end();
     I != E; ++I)
  DelegatingCycleHelper(*I, Valid, Invalid, Current, *this);

for (auto CI = Invalid.begin(), CE = Invalid.end(); CI != CE; ++CI)
  (*CI)->setInvalidDecl();
17775}

17777namespace {
/// AST visitor that finds references to the 'this' expression.
class FindCXXThisExpr : public RecursiveASTVisitor<FindCXXThisExpr> {
  Sema &S;

public:
  explicit FindCXXThisExpr(Sema &S) : S(S) { }

  bool VisitCXXThisExpr(CXXThisExpr *E) {
    S.Diag(E->getLocation(), diag::err_this_static_member_func)
      << E->isImplicit();
    return false;
  }
};
17791}

17793bool Sema::checkThisInStaticMemberFunctionType(CXXMethodDecl *Method) {
TypeSourceInfo *TSInfo = Method->getTypeSourceInfo();
if (!TSInfo)
  return false;

TypeLoc TL = TSInfo->getTypeLoc();
FunctionProtoTypeLoc ProtoTL = TL.getAs<FunctionProtoTypeLoc>();
if (!ProtoTL)
  return false;

// C++11 [expr.prim.general]p3:
//   [The expression this] shall not appear before the optional
//   cv-qualifier-seq and it shall not appear within the declaration of a
//   static member function (although its type and value category are defined
//   within a static member function as they are within a non-static member
//   function). [ Note: this is because declaration matching does not occur
//  until the complete declarator is known. - end note ]
const FunctionProtoType *Proto = ProtoTL.getTypePtr();
FindCXXThisExpr Finder(*this);

// If the return type came after the cv-qualifier-seq, check it now.
if (Proto->hasTrailingReturn() &&
    !Finder.TraverseTypeLoc(ProtoTL.getReturnLoc()))
  return true;

// Check the exception specification.
if (checkThisInStaticMemberFunctionExceptionSpec(Method))
  return true;

// Check the trailing requires clause
if (Expr *E = Method->getTrailingRequiresClause())
  if (!Finder.TraverseStmt(E))
    return true;

return checkThisInStaticMemberFunctionAttributes(Method);
17828}

17830bool Sema::checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method) {
TypeSourceInfo *TSInfo = Method->getTypeSourceInfo();
if (!TSInfo)
  return false;

TypeLoc TL = TSInfo->getTypeLoc();
FunctionProtoTypeLoc ProtoTL = TL.getAs<FunctionProtoTypeLoc>();
if (!ProtoTL)
  return false;

const FunctionProtoType *Proto = ProtoTL.getTypePtr();
FindCXXThisExpr Finder(*this);

switch (Proto->getExceptionSpecType()) {
case EST_Unparsed:
case EST_Uninstantiated:
case EST_Unevaluated:
case EST_BasicNoexcept:
case EST_NoThrow:
case EST_DynamicNone:
case EST_MSAny:
case EST_None:
  break;

case EST_DependentNoexcept:
case EST_NoexceptFalse:
case EST_NoexceptTrue:
  if (!Finder.TraverseStmt(Proto->getNoexceptExpr()))
    return true;
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case EST_Dynamic:
  for (const auto &E : Proto->exceptions()) {
    if (!Finder.TraverseType(E))
      return true;
  }
  break;
}

return false;
17870}

17872bool Sema::checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method) {
FindCXXThisExpr Finder(*this);

// Check attributes.
for (const auto *A : Method->attrs()) {
  // FIXME: This should be emitted by tblgen.
  Expr *Arg = nullptr;
  ArrayRef<Expr *> Args;
  if (const auto *G = dyn_cast<GuardedByAttr>(A))
    Arg = G->getArg();
  else if (const auto *G = dyn_cast<PtGuardedByAttr>(A))
    Arg = G->getArg();
  else if (const auto *AA = dyn_cast<AcquiredAfterAttr>(A))
    Args = llvm::makeArrayRef(AA->args_begin(), AA->args_size());
  else if (const auto *AB = dyn_cast<AcquiredBeforeAttr>(A))
    Args = llvm::makeArrayRef(AB->args_begin(), AB->args_size());
  else if (const auto *ETLF = dyn_cast<ExclusiveTrylockFunctionAttr>(A)) {
    Arg = ETLF->getSuccessValue();
    Args = llvm::makeArrayRef(ETLF->args_begin(), ETLF->args_size());
  } else if (const auto *STLF = dyn_cast<SharedTrylockFunctionAttr>(A)) {
    Arg = STLF->getSuccessValue();
    Args = llvm::makeArrayRef(STLF->args_begin(), STLF->args_size());
  } else if (const auto *LR = dyn_cast<LockReturnedAttr>(A))
    Arg = LR->getArg();
  else if (const auto *LE = dyn_cast<LocksExcludedAttr>(A))
    Args = llvm::makeArrayRef(LE->args_begin(), LE->args_size());
  else if (const auto *RC = dyn_cast<RequiresCapabilityAttr>(A))
    Args = llvm::makeArrayRef(RC->args_begin(), RC->args_size());
  else if (const auto *AC = dyn_cast<AcquireCapabilityAttr>(A))
    Args = llvm::makeArrayRef(AC->args_begin(), AC->args_size());
  else if (const auto *AC = dyn_cast<TryAcquireCapabilityAttr>(A))
    Args = llvm::makeArrayRef(AC->args_begin(), AC->args_size());
  else if (const auto *RC = dyn_cast<ReleaseCapabilityAttr>(A))
    Args = llvm::makeArrayRef(RC->args_begin(), RC->args_size());

  if (Arg && !Finder.TraverseStmt(Arg))
    return true;

  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
    if (!Finder.TraverseStmt(Args[I]))
      return true;
  }
}

return false;
17917}

17919void Sema::checkExceptionSpecification(
  bool IsTopLevel, ExceptionSpecificationType EST,
  ArrayRef<ParsedType> DynamicExceptions,
  ArrayRef<SourceRange> DynamicExceptionRanges, Expr *NoexceptExpr,
  SmallVectorImpl<QualType> &Exceptions,
  FunctionProtoType::ExceptionSpecInfo &ESI) {
Exceptions.clear();
ESI.Type = EST;
if (EST == EST_Dynamic) {
  Exceptions.reserve(DynamicExceptions.size());
  for (unsigned ei = 0, ee = DynamicExceptions.size(); ei != ee; ++ei) {
    // FIXME: Preserve type source info.
    QualType ET = GetTypeFromParser(DynamicExceptions[ei]);

    if (IsTopLevel) {
      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
      collectUnexpandedParameterPacks(ET, Unexpanded);
      if (!Unexpanded.empty()) {
        DiagnoseUnexpandedParameterPacks(
            DynamicExceptionRanges[ei].getBegin(), UPPC_ExceptionType,
            Unexpanded);
        continue;
      }
    }

    // Check that the type is valid for an exception spec, and
    // drop it if not.
    if (!CheckSpecifiedExceptionType(ET, DynamicExceptionRanges[ei]))
      Exceptions.push_back(ET);
  }
  ESI.Exceptions = Exceptions;
  return;
}

if (isComputedNoexcept(EST)) {
  assert((NoexceptExpr->isTypeDependent() ||((void)0)
          NoexceptExpr->getType()->getCanonicalTypeUnqualified() ==((void)0)
          Context.BoolTy) &&((void)0)
         "Parser should have made sure that the expression is boolean")((void)0);
  if (IsTopLevel && DiagnoseUnexpandedParameterPack(NoexceptExpr)) {
    ESI.Type = EST_BasicNoexcept;
    return;
  }

  ESI.NoexceptExpr = NoexceptExpr;
  return;
}
17966}

17968void Sema::actOnDelayedExceptionSpecification(Decl *MethodD,
           ExceptionSpecificationType EST,
           SourceRange SpecificationRange,
           ArrayRef<ParsedType> DynamicExceptions,
           ArrayRef<SourceRange> DynamicExceptionRanges,
           Expr *NoexceptExpr) {
if (!MethodD)
  return;

// Dig out the method we're referring to.
if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(MethodD))
  MethodD = FunTmpl->getTemplatedDecl();

CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(MethodD);
if (!Method)
  return;

// Check the exception specification.
llvm::SmallVector<QualType, 4> Exceptions;
FunctionProtoType::ExceptionSpecInfo ESI;
checkExceptionSpecification(/*IsTopLevel*/true, EST, DynamicExceptions,
                            DynamicExceptionRanges, NoexceptExpr, Exceptions,
                            ESI);

// Update the exception specification on the function type.
Context.adjustExceptionSpec(Method, ESI, /*AsWritten*/true);

if (Method->isStatic())
  checkThisInStaticMemberFunctionExceptionSpec(Method);

if (Method->isVirtual()) {
  // Check overrides, which we previously had to delay.
  for (const CXXMethodDecl *O : Method->overridden_methods())
    CheckOverridingFunctionExceptionSpec(Method, O);
}
18003}

18005/// HandleMSProperty - Analyze a __delcspec(property) field of a C++ class.
18006///
18007MSPropertyDecl *Sema::HandleMSProperty(Scope *S, RecordDecl *Record,
                                     SourceLocation DeclStart, Declarator &D,
                                     Expr *BitWidth,
                                     InClassInitStyle InitStyle,
                                     AccessSpecifier AS,
                                     const ParsedAttr &MSPropertyAttr) {
IdentifierInfo *II = D.getIdentifier();
if (!II) {
  Diag(DeclStart, diag::err_anonymous_property);
  return nullptr;
}
SourceLocation Loc = D.getIdentifierLoc();

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType T = TInfo->getType();
if (getLangOpts().CPlusPlus) {
  CheckExtraCXXDefaultArguments(D);

  if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
                                      UPPC_DataMemberType)) {
    D.setInvalidType();
    T = Context.IntTy;
    TInfo = Context.getTrivialTypeSourceInfo(T, Loc);
  }
}

DiagnoseFunctionSpecifiers(D.getDeclSpec());

if (D.getDeclSpec().isInlineSpecified())
  Diag(D.getDeclSpec().getInlineSpecLoc(), diag::err_inline_non_function)
      << getLangOpts().CPlusPlus17;
if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
  Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
       diag::err_invalid_thread)
    << DeclSpec::getSpecifierName(TSCS);

// Check to see if this name was declared as a member previously
NamedDecl *PrevDecl = nullptr;
LookupResult Previous(*this, II, Loc, LookupMemberName,
                      ForVisibleRedeclaration);
LookupName(Previous, S);
switch (Previous.getResultKind()) {
case LookupResult::Found:
case LookupResult::FoundUnresolvedValue:
  PrevDecl = Previous.getAsSingle<NamedDecl>();
  break;

case LookupResult::FoundOverloaded:
  PrevDecl = Previous.getRepresentativeDecl();
  break;

case LookupResult::NotFound:
case LookupResult::NotFoundInCurrentInstantiation:
case LookupResult::Ambiguous:
  break;
}

if (PrevDecl && PrevDecl->isTemplateParameter()) {
  // Maybe we will complain about the shadowed template parameter.
  DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
  // Just pretend that we didn't see the previous declaration.
  PrevDecl = nullptr;
}

if (PrevDecl && !isDeclInScope(PrevDecl, Record, S))
  PrevDecl = nullptr;

SourceLocation TSSL = D.getBeginLoc();
MSPropertyDecl *NewPD =
    MSPropertyDecl::Create(Context, Record, Loc, II, T, TInfo, TSSL,
                           MSPropertyAttr.getPropertyDataGetter(),
                           MSPropertyAttr.getPropertyDataSetter());
ProcessDeclAttributes(TUScope, NewPD, D);
NewPD->setAccess(AS);

if (NewPD->isInvalidDecl())
  Record->setInvalidDecl();

if (D.getDeclSpec().isModulePrivateSpecified())
  NewPD->setModulePrivate();

if (NewPD->isInvalidDecl() && PrevDecl) {
  // Don't introduce NewFD into scope; there's already something
  // with the same name in the same scope.
} else if (II) {
  PushOnScopeChains(NewPD, S);
} else
  Record->addDecl(NewPD);

return NewPD;
18097}

18099void Sema::ActOnStartFunctionDeclarationDeclarator(
  Declarator &Declarator, unsigned TemplateParameterDepth) {
auto &Info = InventedParameterInfos.emplace_back();
TemplateParameterList *ExplicitParams = nullptr;
ArrayRef<TemplateParameterList *> ExplicitLists =
    Declarator.getTemplateParameterLists();
if (!ExplicitLists.empty()) {
  bool IsMemberSpecialization, IsInvalid;
  ExplicitParams = MatchTemplateParametersToScopeSpecifier(
      Declarator.getBeginLoc(), Declarator.getIdentifierLoc(),
      Declarator.getCXXScopeSpec(), /*TemplateId=*/nullptr,
      ExplicitLists, /*IsFriend=*/false, IsMemberSpecialization, IsInvalid,
      /*SuppressDiagnostic=*/true);
}
if (ExplicitParams) {
  Info.AutoTemplateParameterDepth = ExplicitParams->getDepth();
  for (NamedDecl *Param : *ExplicitParams)
    Info.TemplateParams.push_back(Param);
  Info.NumExplicitTemplateParams = ExplicitParams->size();
} else {
  Info.AutoTemplateParameterDepth = TemplateParameterDepth;
  Info.NumExplicitTemplateParams = 0;
}
18122}

18124void Sema::ActOnFinishFunctionDeclarationDeclarator(Declarator &Declarator) {
auto &FSI = InventedParameterInfos.back();
if (FSI.TemplateParams.size() > FSI.NumExplicitTemplateParams) {
  if (FSI.NumExplicitTemplateParams != 0) {
    TemplateParameterList *ExplicitParams =
        Declarator.getTemplateParameterLists().back();
    Declarator.setInventedTemplateParameterList(
        TemplateParameterList::Create(
            Context, ExplicitParams->getTemplateLoc(),
            ExplicitParams->getLAngleLoc(), FSI.TemplateParams,
            ExplicitParams->getRAngleLoc(),
            ExplicitParams->getRequiresClause()));
  } else {
    Declarator.setInventedTemplateParameterList(
        TemplateParameterList::Create(
            Context, SourceLocation(), SourceLocation(), FSI.TemplateParams,
            SourceLocation(), /*RequiresClause=*/nullptr));
  }
}
InventedParameterInfos.pop_back();
18144}