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

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiate.cpp
Warning:	line 2694, column 29 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 SemaTemplateInstantiate.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/SemaTemplateInstantiate.cpp

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

→

1//===------- SemaTemplateInstantiate.cpp - C++ Template Instantiation ------===/
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//  This file implements C++ template instantiation.
9//
10//===----------------------------------------------------------------------===/

12#include "TreeTransform.h"
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/DeclTemplate.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/PrettyDeclStackTrace.h"
20#include "clang/AST/TypeVisitor.h"
21#include "clang/Basic/LangOptions.h"
22#include "clang/Basic/Stack.h"
23#include "clang/Basic/TargetInfo.h"
24#include "clang/Sema/DeclSpec.h"
25#include "clang/Sema/Initialization.h"
26#include "clang/Sema/Lookup.h"
27#include "clang/Sema/SemaConcept.h"
28#include "clang/Sema/SemaInternal.h"
29#include "clang/Sema/Template.h"
30#include "clang/Sema/TemplateDeduction.h"
31#include "clang/Sema/TemplateInstCallback.h"
32#include "llvm/Support/TimeProfiler.h"

34using namespace clang;
35using namespace sema;

37//===----------------------------------------------------------------------===/
38// Template Instantiation Support
39//===----------------------------------------------------------------------===/

41/// Retrieve the template argument list(s) that should be used to
42/// instantiate the definition of the given declaration.
43///
44/// \param D the declaration for which we are computing template instantiation
45/// arguments.
46///
47/// \param Innermost if non-NULL, the innermost template argument list.
48///
49/// \param RelativeToPrimary true if we should get the template
50/// arguments relative to the primary template, even when we're
51/// dealing with a specialization. This is only relevant for function
52/// template specializations.
53///
54/// \param Pattern If non-NULL, indicates the pattern from which we will be
55/// instantiating the definition of the given declaration, \p D. This is
56/// used to determine the proper set of template instantiation arguments for
57/// friend function template specializations.
58MultiLevelTemplateArgumentList
59Sema::getTemplateInstantiationArgs(NamedDecl *D,
                                 const TemplateArgumentList *Innermost,
                                 bool RelativeToPrimary,
                                 const FunctionDecl *Pattern) {
// Accumulate the set of template argument lists in this structure.
MultiLevelTemplateArgumentList Result;

if (Innermost)
  Result.addOuterTemplateArguments(Innermost);

DeclContext *Ctx = dyn_cast<DeclContext>(D);
if (!Ctx) {
  Ctx = D->getDeclContext();

  // Add template arguments from a variable template instantiation. For a
  // class-scope explicit specialization, there are no template arguments
  // at this level, but there may be enclosing template arguments.
  VarTemplateSpecializationDecl *Spec =
      dyn_cast<VarTemplateSpecializationDecl>(D);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<VarTemplatePartialSpecializationDecl>(Spec))
      return Result;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this variable template specialization was instantiated from a
    // specialized member that is a variable template, we're done.
    assert(Spec->getSpecializedTemplate() && "No variable template?")((void)0);
    llvm::PointerUnion<VarTemplateDecl*,
                       VarTemplatePartialSpecializationDecl*> Specialized
                           = Spec->getSpecializedTemplateOrPartial();
    if (VarTemplatePartialSpecializationDecl *Partial =
            Specialized.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
      if (Partial->isMemberSpecialization())
        return Result;
    } else {
      VarTemplateDecl *Tmpl = Specialized.get<VarTemplateDecl *>();
      if (Tmpl->isMemberSpecialization())
        return Result;
    }
  }

  // If we have a template template parameter with translation unit context,
  // then we're performing substitution into a default template argument of
  // this template template parameter before we've constructed the template
  // that will own this template template parameter. In this case, we
  // use empty template parameter lists for all of the outer templates
  // to avoid performing any substitutions.
  if (Ctx->isTranslationUnit()) {
    if (TemplateTemplateParmDecl *TTP
                                    = dyn_cast<TemplateTemplateParmDecl>(D)) {
      for (unsigned I = 0, N = TTP->getDepth() + 1; I != N; ++I)
        Result.addOuterTemplateArguments(None);
      return Result;
    }
  }
}

while (!Ctx->isFileContext()) {
  // Add template arguments from a class template instantiation.
  ClassTemplateSpecializationDecl *Spec
        = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<ClassTemplatePartialSpecializationDecl>(Spec))
      break;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this class template specialization was instantiated from a
    // specialized member that is a class template, we're done.
    assert(Spec->getSpecializedTemplate() && "No class template?")((void)0);
    if (Spec->getSpecializedTemplate()->isMemberSpecialization())
      break;
  }
  // Add template arguments from a function template specialization.
  else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Ctx)) {
    if (!RelativeToPrimary &&
        Function->getTemplateSpecializationKindForInstantiation() ==
            TSK_ExplicitSpecialization)
      break;

    if (!RelativeToPrimary && Function->getTemplateSpecializationKind() ==
                                  TSK_ExplicitSpecialization) {
      // This is an implicit instantiation of an explicit specialization. We
      // don't get any template arguments from this function but might get
      // some from an enclosing template.
    } else if (const TemplateArgumentList *TemplateArgs
          = Function->getTemplateSpecializationArgs()) {
      // Add the template arguments for this specialization.
      Result.addOuterTemplateArguments(TemplateArgs);

      // If this function was instantiated from a specialized member that is
      // a function template, we're done.
      assert(Function->getPrimaryTemplate() && "No function template?")((void)0);
      if (Function->getPrimaryTemplate()->isMemberSpecialization())
        break;

      // If this function is a generic lambda specialization, we are done.
      if (isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function))
        break;

    } else if (FunctionTemplateDecl *FunTmpl
                                 = Function->getDescribedFunctionTemplate()) {
      // Add the "injected" template arguments.
      Result.addOuterTemplateArguments(FunTmpl->getInjectedTemplateArgs());
    }

    // If this is a friend declaration and it declares an entity at
    // namespace scope, take arguments from its lexical parent
    // instead of its semantic parent, unless of course the pattern we're
    // instantiating actually comes from the file's context!
    if (Function->getFriendObjectKind() &&
        Function->getDeclContext()->isFileContext() &&
        (!Pattern || !Pattern->getLexicalDeclContext()->isFileContext())) {
      Ctx = Function->getLexicalDeclContext();
      RelativeToPrimary = false;
      continue;
    }
  } else if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Ctx)) {
    if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) {
      QualType T = ClassTemplate->getInjectedClassNameSpecialization();
      const TemplateSpecializationType *TST =
          cast<TemplateSpecializationType>(Context.getCanonicalType(T));
      Result.addOuterTemplateArguments(
          llvm::makeArrayRef(TST->getArgs(), TST->getNumArgs()));
      if (ClassTemplate->isMemberSpecialization())
        break;
    }
  }

  Ctx = Ctx->getParent();
  RelativeToPrimary = false;
}

return Result;
198}

200bool Sema::CodeSynthesisContext::isInstantiationRecord() const {
switch (Kind) {
case TemplateInstantiation:
case ExceptionSpecInstantiation:
case DefaultTemplateArgumentInstantiation:
case DefaultFunctionArgumentInstantiation:
case ExplicitTemplateArgumentSubstitution:
case DeducedTemplateArgumentSubstitution:
case PriorTemplateArgumentSubstitution:
case ConstraintsCheck:
case NestedRequirementConstraintsCheck:
  return true;

case RequirementInstantiation:
case DefaultTemplateArgumentChecking:
case DeclaringSpecialMember:
case DeclaringImplicitEqualityComparison:
case DefiningSynthesizedFunction:
case ExceptionSpecEvaluation:
case ConstraintSubstitution:
case ParameterMappingSubstitution:
case ConstraintNormalization:
case RewritingOperatorAsSpaceship:
case InitializingStructuredBinding:
case MarkingClassDllexported:
  return false;

// This function should never be called when Kind's value is Memoization.
case Memoization:
  break;
}

llvm_unreachable("Invalid SynthesisKind!")__builtin_unreachable();
233}

235Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
  SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
  Decl *Entity, NamedDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo *DeductionInfo)
  : SemaRef(SemaRef) {
// Don't allow further instantiation if a fatal error and an uncompilable
// error have occurred. Any diagnostics we might have raised will not be
// visible, and we do not need to construct a correct AST.
if (SemaRef.Diags.hasFatalErrorOccurred() &&
18
←
Assuming the condition is false→
    SemaRef.hasUncompilableErrorOccurred()) {
  Invalid = true;
  return;
}
Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
19
←
Calling 'InstantiatingTemplate::CheckInstantiationDepth'→
23
←
Returning from 'InstantiatingTemplate::CheckInstantiationDepth'→
if (!Invalid23.1
Field 'Invalid' is false
1
Field 'Invalid' is false
) {
24
←
Taking true branch→
  CodeSynthesisContext Inst;
  Inst.Kind = Kind;
  Inst.PointOfInstantiation = PointOfInstantiation;
  Inst.Entity = Entity;
  Inst.Template = Template;
  Inst.TemplateArgs = TemplateArgs.data();
  Inst.NumTemplateArgs = TemplateArgs.size();
  Inst.DeductionInfo = DeductionInfo;
  Inst.InstantiationRange = InstantiationRange;
  SemaRef.pushCodeSynthesisContext(Inst);

  AlreadyInstantiating = !Inst.Entity24.1
Field 'Entity' is non-null
1
Field 'Entity' is non-null
 ? false :
25
←
'?' condition is false→
      !SemaRef.InstantiatingSpecializations
26
←
Assuming field 'second' is true→
           .insert({Inst.Entity->getCanonicalDecl(), Inst.Kind})
           .second;
  atTemplateBegin(SemaRef.TemplateInstCallbacks, SemaRef, Inst);
}
268}

270Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, Decl *Entity,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef,
17
←
Calling constructor for 'InstantiatingTemplate'→
27
←
Returning from constructor for 'InstantiatingTemplate'→
                          CodeSynthesisContext::TemplateInstantiation,
                          PointOfInstantiation, InstantiationRange, Entity) {}

277Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, FunctionDecl *Entity,
  ExceptionSpecification, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ExceptionSpecInstantiation,
        PointOfInstantiation, InstantiationRange, Entity) {}

284Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateParameter Param,
  TemplateDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultTemplateArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, getAsNamedDecl(Param),
        Template, TemplateArgs) {}

294Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  FunctionTemplateDecl *FunctionTemplate,
  ArrayRef<TemplateArgument> TemplateArgs,
  CodeSynthesisContext::SynthesisKind Kind,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef, Kind, PointOfInstantiation,
                          InstantiationRange, FunctionTemplate, nullptr,
                          TemplateArgs, &DeductionInfo) {
assert(((void)0)
  Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution ||((void)0)
  Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution)((void)0);
306}

308Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  TemplateDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs, &DeductionInfo) {}

319Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ClassTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

330Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  VarTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

341Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, ParmVarDecl *Param,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultFunctionArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, Param, nullptr,
        TemplateArgs) {}

350Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  NonTypeTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

360Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  TemplateTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

370Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateDecl *Template,
  NamedDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::DefaultTemplateArgumentChecking,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

379Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::Requirement *Req, sema::TemplateDeductionInfo &DeductionInfo,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::RequirementInstantiation,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None, &DeductionInfo) {}


389Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::NestedRequirement *Req, ConstraintsCheck,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::NestedRequirementConstraintsCheck,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None) {}


399Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintsCheck, NamedDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintsCheck,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs) {}

408Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintSubstitution, NamedDecl *Template,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        {}, &DeductionInfo) {}

417Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintNormalization, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintNormalization,
        PointOfInstantiation, InstantiationRange, Template) {}

425Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ParameterMappingSubstitution, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ParameterMappingSubstitution,
        PointOfInstantiation, InstantiationRange, Template) {}

433void Sema::pushCodeSynthesisContext(CodeSynthesisContext Ctx) {
Ctx.SavedInNonInstantiationSFINAEContext = InNonInstantiationSFINAEContext;
InNonInstantiationSFINAEContext = false;

CodeSynthesisContexts.push_back(Ctx);

if (!Ctx.isInstantiationRecord())
  ++NonInstantiationEntries;

// Check to see if we're low on stack space. We can't do anything about this
// from here, but we can at least warn the user.
if (isStackNearlyExhausted())
  warnStackExhausted(Ctx.PointOfInstantiation);
446}

448void Sema::popCodeSynthesisContext() {
auto &Active = CodeSynthesisContexts.back();
if (!Active.isInstantiationRecord()) {
  assert(NonInstantiationEntries > 0)((void)0);
  --NonInstantiationEntries;
}

InNonInstantiationSFINAEContext = Active.SavedInNonInstantiationSFINAEContext;

// Name lookup no longer looks in this template's defining module.
assert(CodeSynthesisContexts.size() >=((void)0)
           CodeSynthesisContextLookupModules.size() &&((void)0)
       "forgot to remove a lookup module for a template instantiation")((void)0);
if (CodeSynthesisContexts.size() ==
    CodeSynthesisContextLookupModules.size()) {
  if (Module *M = CodeSynthesisContextLookupModules.back())
    LookupModulesCache.erase(M);
  CodeSynthesisContextLookupModules.pop_back();
}

// If we've left the code synthesis context for the current context stack,
// stop remembering that we've emitted that stack.
if (CodeSynthesisContexts.size() ==
    LastEmittedCodeSynthesisContextDepth)
  LastEmittedCodeSynthesisContextDepth = 0;

CodeSynthesisContexts.pop_back();
475}

477void Sema::InstantiatingTemplate::Clear() {
if (!Invalid) {
  if (!AlreadyInstantiating) {
    auto &Active = SemaRef.CodeSynthesisContexts.back();
    if (Active.Entity)
      SemaRef.InstantiatingSpecializations.erase(
          {Active.Entity->getCanonicalDecl(), Active.Kind});
  }

  atTemplateEnd(SemaRef.TemplateInstCallbacks, SemaRef,
                SemaRef.CodeSynthesisContexts.back());

  SemaRef.popCodeSynthesisContext();
  Invalid = true;
}
492}

494bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
                                      SourceLocation PointOfInstantiation,
                                         SourceRange InstantiationRange) {
assert(SemaRef.NonInstantiationEntries <=((void)0)
       SemaRef.CodeSynthesisContexts.size())((void)0);
if ((SemaRef.CodeSynthesisContexts.size() -
20
←
Assuming the condition is true→
21
←
Taking true branch→
        SemaRef.NonInstantiationEntries)
      <= SemaRef.getLangOpts().InstantiationDepth)
  return false;
22
←
Returning zero, which participates in a condition later→

SemaRef.Diag(PointOfInstantiation,
             diag::err_template_recursion_depth_exceeded)
  << SemaRef.getLangOpts().InstantiationDepth
  << InstantiationRange;
SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth)
  << SemaRef.getLangOpts().InstantiationDepth;
return true;
511}

513/// Prints the current instantiation stack through a series of
514/// notes.
515void Sema::PrintInstantiationStack() {
// Determine which template instantiations to skip, if any.
unsigned SkipStart = CodeSynthesisContexts.size(), SkipEnd = SkipStart;
unsigned Limit = Diags.getTemplateBacktraceLimit();
if (Limit && Limit < CodeSynthesisContexts.size()) {
  SkipStart = Limit / 2 + Limit % 2;
  SkipEnd = CodeSynthesisContexts.size() - Limit / 2;
}

// FIXME: In all of these cases, we need to show the template arguments
unsigned InstantiationIdx = 0;
for (SmallVectorImpl<CodeSynthesisContext>::reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active, ++InstantiationIdx) {
  // Skip this instantiation?
  if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) {
    if (InstantiationIdx == SkipStart) {
      // Note that we're skipping instantiations.
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_instantiation_contexts_suppressed)
        << unsigned(CodeSynthesisContexts.size() - Limit);
    }
    continue;
  }

  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation: {
    Decl *D = Active->Entity;
    if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
      unsigned DiagID = diag::note_template_member_class_here;
      if (isa<ClassTemplateSpecializationDecl>(Record))
        DiagID = diag::note_template_class_instantiation_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Record << Active->InstantiationRange;
    } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
      unsigned DiagID;
      if (Function->getPrimaryTemplate())
        DiagID = diag::note_function_template_spec_here;
      else
        DiagID = diag::note_template_member_function_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Function
        << Active->InstantiationRange;
    } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   VD->isStaticDataMember()?
                     diag::note_template_static_data_member_def_here
                   : diag::note_template_variable_def_here)
        << VD
        << Active->InstantiationRange;
    } else if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_enum_def_here)
        << ED
        << Active->InstantiationRange;
    } else if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_nsdmi_here)
          << FD << Active->InstantiationRange;
    } else {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_type_alias_instantiation_here)
        << cast<TypeAliasTemplateDecl>(D)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation: {
    TemplateDecl *Template = cast<TemplateDecl>(Active->Template);
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    Template->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution: {
    FunctionTemplateDecl *FnTmpl = cast<FunctionTemplateDecl>(Active->Entity);
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_explicit_template_arg_substitution_here)
      << FnTmpl
      << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution: {
    if (FunctionTemplateDecl *FnTmpl =
            dyn_cast<FunctionTemplateDecl>(Active->Entity)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_function_template_deduction_instantiation_here)
        << FnTmpl
        << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                           Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    } else {
      bool IsVar = isa<VarTemplateDecl>(Active->Entity) ||
                   isa<VarTemplateSpecializationDecl>(Active->Entity);
      bool IsTemplate = false;
      TemplateParameterList *Params;
      if (auto *D = dyn_cast<TemplateDecl>(Active->Entity)) {
        IsTemplate = true;
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<ClassTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<VarTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else {
        llvm_unreachable("unexpected template kind")__builtin_unreachable();
      }

      Diags.Report(Active->PointOfInstantiation,
                   diag::note_deduced_template_arg_substitution_here)
        << IsVar << IsTemplate << cast<NamedDecl>(Active->Entity)
        << getTemplateArgumentBindingsText(Params, Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation: {
    ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
    FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());

    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    FD->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_function_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::PriorTemplateArgumentSubstitution: {
    NamedDecl *Parm = cast<NamedDecl>(Active->Entity);
    std::string Name;
    if (!Parm->getName().empty())
      Name = std::string(" '") + Parm->getName().str() + "'";

    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_prior_template_arg_substitution)
      << isa<TemplateTemplateParmDecl>(Parm)
      << Name
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentChecking: {
    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();

    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_default_arg_checking)
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_evaluating_exception_spec_here)
        << cast<FunctionDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::ExceptionSpecInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_exception_spec_instantiation_here)
      << cast<FunctionDecl>(Active->Entity)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::RequirementInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_requirement_instantiation_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_nested_requirement_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::DeclaringSpecialMember:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_declaration_of_implicit_special_member)
      << cast<CXXRecordDecl>(Active->Entity) << Active->SpecialMember;
    break;

  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_in_declaration_of_implicit_equality_comparison);
    break;

  case CodeSynthesisContext::DefiningSynthesizedFunction: {
    // FIXME: For synthesized functions that are not defaulted,
    // produce a note.
    auto *FD = dyn_cast<FunctionDecl>(Active->Entity);
    DefaultedFunctionKind DFK =
        FD ? getDefaultedFunctionKind(FD) : DefaultedFunctionKind();
    if (DFK.isSpecialMember()) {
      auto *MD = cast<CXXMethodDecl>(FD);
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_member_synthesized_at)
          << MD->isExplicitlyDefaulted() << DFK.asSpecialMember()
          << Context.getTagDeclType(MD->getParent());
    } else if (DFK.isComparison()) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_comparison_synthesized_at)
          << (int)DFK.asComparison()
          << Context.getTagDeclType(
                 cast<CXXRecordDecl>(FD->getLexicalDeclContext()));
    }
    break;
  }

  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_rewriting_operator_as_spaceship);
    break;

  case CodeSynthesisContext::InitializingStructuredBinding:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_binding_decl_init)
        << cast<BindingDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::MarkingClassDllexported:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_due_to_dllexported_class)
        << cast<CXXRecordDecl>(Active->Entity) << !getLangOpts().CPlusPlus11;
    break;

  case CodeSynthesisContext::Memoization:
    break;

  case CodeSynthesisContext::ConstraintsCheck: {
    unsigned DiagID = 0;
    if (!Active->Entity) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_nested_requirement_here)
        << Active->InstantiationRange;
      break;
    }
    if (isa<ConceptDecl>(Active->Entity))
      DiagID = diag::note_concept_specialization_here;
    else if (isa<TemplateDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_template_id_here;
    else if (isa<VarTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_var_spec_id_here;
    else if (isa<ClassTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_class_spec_id_here;
    else {
      assert(isa<FunctionDecl>(Active->Entity))((void)0);
      DiagID = diag::note_checking_constraints_for_function_here;
    }
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    cast<NamedDecl>(Active->Entity)->printName(OS);
    if (!isa<FunctionDecl>(Active->Entity)) {
      printTemplateArgumentList(OS, Active->template_arguments(),
                                getPrintingPolicy());
    }
    Diags.Report(Active->PointOfInstantiation, DiagID) << OS.str()
      << Active->InstantiationRange;
    break;
  }
  case CodeSynthesisContext::ConstraintSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_substitution_here)
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ConstraintNormalization:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_normalization_here)
        << cast<NamedDecl>(Active->Entity)->getName()
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ParameterMappingSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_parameter_mapping_substitution_here)
        << Active->InstantiationRange;
    break;
  }
}
834}

836Optional<TemplateDeductionInfo *> Sema::isSFINAEContext() const {
if (InNonInstantiationSFINAEContext)
  return Optional<TemplateDeductionInfo *>(nullptr);

for (SmallVectorImpl<CodeSynthesisContext>::const_reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active)
{
  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation:
    // An instantiation of an alias template may or may not be a SFINAE
    // context, depending on what else is on the stack.
    if (isa<TypeAliasTemplateDecl>(Active->Entity))
      break;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation:
  case CodeSynthesisContext::ExceptionSpecInstantiation:
  case CodeSynthesisContext::ConstraintsCheck:
  case CodeSynthesisContext::ParameterMappingSubstitution:
  case CodeSynthesisContext::ConstraintNormalization:
  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    // This is a template instantiation, so there is no SFINAE.
    return None;

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation:
  case CodeSynthesisContext::PriorTemplateArgumentSubstitution:
  case CodeSynthesisContext::DefaultTemplateArgumentChecking:
  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    // A default template argument instantiation and substitution into
    // template parameters with arguments for prior parameters may or may
    // not be a SFINAE context; look further up the stack.
    break;

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution:
  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution:
  case CodeSynthesisContext::ConstraintSubstitution:
  case CodeSynthesisContext::RequirementInstantiation:
    // We're either substituting explicitly-specified template arguments,
    // deduced template arguments, a constraint expression or a requirement
    // in a requires expression, so SFINAE applies.
    assert(Active->DeductionInfo && "Missing deduction info pointer")((void)0);
    return Active->DeductionInfo;

  case CodeSynthesisContext::DeclaringSpecialMember:
  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
  case CodeSynthesisContext::DefiningSynthesizedFunction:
  case CodeSynthesisContext::InitializingStructuredBinding:
  case CodeSynthesisContext::MarkingClassDllexported:
    // This happens in a context unrelated to template instantiation, so
    // there is no SFINAE.
    return None;

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    // FIXME: This should not be treated as a SFINAE context, because
    // we will cache an incorrect exception specification. However, clang
    // bootstrap relies this! See PR31692.
    break;

  case CodeSynthesisContext::Memoization:
    break;
  }

  // The inner context was transparent for SFINAE. If it occurred within a
  // non-instantiation SFINAE context, then SFINAE applies.
  if (Active->SavedInNonInstantiationSFINAEContext)
    return Optional<TemplateDeductionInfo *>(nullptr);
}

return None;
907}

909//===----------------------------------------------------------------------===/
910// Template Instantiation for Types
911//===----------------------------------------------------------------------===/
912namespace {
class TemplateInstantiator : public TreeTransform<TemplateInstantiator> {
  const MultiLevelTemplateArgumentList &TemplateArgs;
  SourceLocation Loc;
  DeclarationName Entity;

public:
  typedef TreeTransform<TemplateInstantiator> inherited;

  TemplateInstantiator(Sema &SemaRef,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc,
                       DeclarationName Entity)
    : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc),
      Entity(Entity) { }

  /// Determine whether the given type \p T has already been
  /// transformed.
  ///
  /// For the purposes of template instantiation, a type has already been
  /// transformed if it is NULL or if it is not dependent.
  bool AlreadyTransformed(QualType T);

  /// Returns the location of the entity being instantiated, if known.
  SourceLocation getBaseLocation() { return Loc; }

  /// Returns the name of the entity being instantiated, if any.
  DeclarationName getBaseEntity() { return Entity; }

  /// Sets the "base" location and entity when that
  /// information is known based on another transformation.
  void setBase(SourceLocation Loc, DeclarationName Entity) {
    this->Loc = Loc;
    this->Entity = Entity;
  }

  unsigned TransformTemplateDepth(unsigned Depth) {
    return TemplateArgs.getNewDepth(Depth);
  }

  bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
                               SourceRange PatternRange,
                               ArrayRef<UnexpandedParameterPack> Unexpanded,
                               bool &ShouldExpand, bool &RetainExpansion,
                               Optional<unsigned> &NumExpansions) {
    return getSema().CheckParameterPacksForExpansion(EllipsisLoc,
                                                     PatternRange, Unexpanded,
                                                     TemplateArgs,
                                                     ShouldExpand,
                                                     RetainExpansion,
                                                     NumExpansions);
  }

  void ExpandingFunctionParameterPack(ParmVarDecl *Pack) {
    SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Pack);
  }

  TemplateArgument ForgetPartiallySubstitutedPack() {
    TemplateArgument Result;
    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
        = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      if (TemplateArgs.hasTemplateArgument(Depth, Index)) {
        Result = TemplateArgs(Depth, Index);
        TemplateArgs.setArgument(Depth, Index, TemplateArgument());
      }
    }

    return Result;
  }

  void RememberPartiallySubstitutedPack(TemplateArgument Arg) {
    if (Arg.isNull())
      return;

    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
      = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      TemplateArgs.setArgument(Depth, Index, Arg);
    }
  }

  /// Transform the given declaration by instantiating a reference to
  /// this declaration.
  Decl *TransformDecl(SourceLocation Loc, Decl *D);

  void transformAttrs(Decl *Old, Decl *New) {
    SemaRef.InstantiateAttrs(TemplateArgs, Old, New);
  }

  void transformedLocalDecl(Decl *Old, ArrayRef<Decl *> NewDecls) {
    if (Old->isParameterPack()) {
      SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Old);
      for (auto *New : NewDecls)
        SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(
            Old, cast<VarDecl>(New));
      return;
    }

    assert(NewDecls.size() == 1 &&((void)0)
           "should only have multiple expansions for a pack")((void)0);
    Decl *New = NewDecls.front();

    // If we've instantiated the call operator of a lambda or the call
    // operator template of a generic lambda, update the "instantiation of"
    // information.
    auto *NewMD = dyn_cast<CXXMethodDecl>(New);
    if (NewMD && isLambdaCallOperator(NewMD)) {
      auto *OldMD = dyn_cast<CXXMethodDecl>(Old);
      if (auto *NewTD = NewMD->getDescribedFunctionTemplate())
        NewTD->setInstantiatedFromMemberTemplate(
            OldMD->getDescribedFunctionTemplate());
      else
        NewMD->setInstantiationOfMemberFunction(OldMD,
                                                TSK_ImplicitInstantiation);
    }

    SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New);

    // We recreated a local declaration, but not by instantiating it. There
    // may be pending dependent diagnostics to produce.
    if (auto *DC = dyn_cast<DeclContext>(Old))
      SemaRef.PerformDependentDiagnostics(DC, TemplateArgs);
  }

  /// Transform the definition of the given declaration by
  /// instantiating it.
  Decl *TransformDefinition(SourceLocation Loc, Decl *D);

  /// Transform the first qualifier within a scope by instantiating the
  /// declaration.
  NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc);

  /// Rebuild the exception declaration and register the declaration
  /// as an instantiated local.
  VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                TypeSourceInfo *Declarator,
                                SourceLocation StartLoc,
                                SourceLocation NameLoc,
                                IdentifierInfo *Name);

  /// Rebuild the Objective-C exception declaration and register the
  /// declaration as an instantiated local.
  VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                    TypeSourceInfo *TSInfo, QualType T);

  /// Check for tag mismatches when instantiating an
  /// elaborated type.
  QualType RebuildElaboratedType(SourceLocation KeywordLoc,
                                 ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifierLoc QualifierLoc,
                                 QualType T);

  TemplateName
  TransformTemplateName(CXXScopeSpec &SS, TemplateName Name,
                        SourceLocation NameLoc,
                        QualType ObjectType = QualType(),
                        NamedDecl *FirstQualifierInScope = nullptr,
                        bool AllowInjectedClassName = false);

  const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH);

  ExprResult TransformPredefinedExpr(PredefinedExpr *E);
  ExprResult TransformDeclRefExpr(DeclRefExpr *E);
  ExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E);

  ExprResult TransformTemplateParmRefExpr(DeclRefExpr *E,
                                          NonTypeTemplateParmDecl *D);
  ExprResult TransformSubstNonTypeTemplateParmPackExpr(
                                         SubstNonTypeTemplateParmPackExpr *E);
  ExprResult TransformSubstNonTypeTemplateParmExpr(
                                         SubstNonTypeTemplateParmExpr *E);

  /// Rebuild a DeclRefExpr for a VarDecl reference.
  ExprResult RebuildVarDeclRefExpr(VarDecl *PD, SourceLocation Loc);

  /// Transform a reference to a function or init-capture parameter pack.
  ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E, VarDecl *PD);

  /// Transform a FunctionParmPackExpr which was built when we couldn't
  /// expand a function parameter pack reference which refers to an expanded
  /// pack.
  ExprResult TransformFunctionParmPackExpr(FunctionParmPackExpr *E);

  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL) {
    // Call the base version; it will forward to our overridden version below.
    return inherited::TransformFunctionProtoType(TLB, TL);
  }

  template<typename Fn>
  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals,
                                      Fn TransformExceptionSpec);

  ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                          int indexAdjustment,
                                          Optional<unsigned> NumExpansions,
                                          bool ExpectParameterPack);

  /// Transforms a template type parameter type by performing
  /// substitution of the corresponding template type argument.
  QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                         TemplateTypeParmTypeLoc TL);

  /// Transforms an already-substituted template type parameter pack
  /// into either itself (if we aren't substituting into its pack expansion)
  /// or the appropriate substituted argument.
  QualType TransformSubstTemplateTypeParmPackType(TypeLocBuilder &TLB,
                                         SubstTemplateTypeParmPackTypeLoc TL);

  ExprResult TransformLambdaExpr(LambdaExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return TreeTransform<TemplateInstantiator>::TransformLambdaExpr(E);
  }

  ExprResult TransformRequiresExpr(RequiresExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return TreeTransform<TemplateInstantiator>::TransformRequiresExpr(E);
  }

  bool TransformRequiresExprRequirements(
      ArrayRef<concepts::Requirement *> Reqs,
      SmallVectorImpl<concepts::Requirement *> &Transformed) {
    bool SatisfactionDetermined = false;
    for (concepts::Requirement *Req : Reqs) {
      concepts::Requirement *TransReq = nullptr;
      if (!SatisfactionDetermined) {
        if (auto *TypeReq = dyn_cast<concepts::TypeRequirement>(Req))
          TransReq = TransformTypeRequirement(TypeReq);
        else if (auto *ExprReq = dyn_cast<concepts::ExprRequirement>(Req))
          TransReq = TransformExprRequirement(ExprReq);
        else
          TransReq = TransformNestedRequirement(
              cast<concepts::NestedRequirement>(Req));
        if (!TransReq)
          return true;
        if (!TransReq->isDependent() && !TransReq->isSatisfied())
          // [expr.prim.req]p6
          //   [...]  The substitution and semantic constraint checking
          //   proceeds in lexical order and stops when a condition that
          //   determines the result of the requires-expression is
          //   encountered. [..]
          SatisfactionDetermined = true;
      } else
        TransReq = Req;
      Transformed.push_back(TransReq);
    }
    return false;
  }

  TemplateParameterList *TransformTemplateParameterList(
                            TemplateParameterList *OrigTPL)  {
    if (!OrigTPL || !OrigTPL->size()) return OrigTPL;

    DeclContext *Owner = OrigTPL->getParam(0)->getDeclContext();
    TemplateDeclInstantiator  DeclInstantiator(getSema(),
                      /* DeclContext *Owner */ Owner, TemplateArgs);
    return DeclInstantiator.SubstTemplateParams(OrigTPL);
  }

  concepts::TypeRequirement *
  TransformTypeRequirement(concepts::TypeRequirement *Req);
  concepts::ExprRequirement *
  TransformExprRequirement(concepts::ExprRequirement *Req);
  concepts::NestedRequirement *
  TransformNestedRequirement(concepts::NestedRequirement *Req);

private:
  ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm,
                                             SourceLocation loc,
                                             TemplateArgument arg);
};
1193}

1195bool TemplateInstantiator::AlreadyTransformed(QualType T) {
if (T.isNull())
  return true;

if (T->isInstantiationDependentType() || T->isVariablyModifiedType())
  return false;

getSema().MarkDeclarationsReferencedInType(Loc, T);
return true;
1204}

1206static TemplateArgument
1207getPackSubstitutedTemplateArgument(Sema &S, TemplateArgument Arg) {
assert(S.ArgumentPackSubstitutionIndex >= 0)((void)0);
assert(S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size())((void)0);
Arg = Arg.pack_begin()[S.ArgumentPackSubstitutionIndex];
if (Arg.isPackExpansion())
  Arg = Arg.getPackExpansionPattern();
return Arg;
1214}

1216Decl *TemplateInstantiator::TransformDecl(SourceLocation Loc, Decl *D) {
if (!D)
  return nullptr;

if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return D;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);
      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && Template.getAsTemplateDecl() &&((void)0)
           "Wrong kind of template template argument")((void)0);
    return Template.getAsTemplateDecl();
  }

  // Fall through to find the instantiated declaration for this template
  // template parameter.
}

return SemaRef.FindInstantiatedDecl(Loc, cast<NamedDecl>(D), TemplateArgs);
1249}

1251Decl *TemplateInstantiator::TransformDefinition(SourceLocation Loc, Decl *D) {
Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
if (!Inst)
  return nullptr;

getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
return Inst;
1258}

1260NamedDecl *
1261TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
                                                   SourceLocation Loc) {
// If the first part of the nested-name-specifier was a template type
// parameter, instantiate that type parameter down to a tag type.
if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
  const TemplateTypeParmType *TTP
    = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));

  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // FIXME: This needs testing w/ member access expressions.
    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getIndex());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);

      if (getSema().ArgumentPackSubstitutionIndex == -1)
        return nullptr;

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    QualType T = Arg.getAsType();
    if (T.isNull())
      return cast_or_null<NamedDecl>(TransformDecl(Loc, D));

    if (const TagType *Tag = T->getAs<TagType>())
      return Tag->getDecl();

    // The resulting type is not a tag; complain.
    getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
    return nullptr;
  }
}

return cast_or_null<NamedDecl>(TransformDecl(Loc, D));
1297}

1299VarDecl *
1300TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                         TypeSourceInfo *Declarator,
                                         SourceLocation StartLoc,
                                         SourceLocation NameLoc,
                                         IdentifierInfo *Name) {
VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, Declarator,
                                               StartLoc, NameLoc, Name);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1310}

1312VarDecl *TemplateInstantiator::RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                                      TypeSourceInfo *TSInfo,
                                                      QualType T) {
VarDecl *Var = inherited::RebuildObjCExceptionDecl(ExceptionDecl, TSInfo, T);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1319}

1321QualType
1322TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc,
                                          ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifierLoc QualifierLoc,
                                          QualType T) {
if (const TagType *TT = T->getAs<TagType>()) {
  TagDecl* TD = TT->getDecl();

  SourceLocation TagLocation = KeywordLoc;

  IdentifierInfo *Id = TD->getIdentifier();

  // TODO: should we even warn on struct/class mismatches for this?  Seems
  // like it's likely to produce a lot of spurious errors.
  if (Id && Keyword != ETK_None && Keyword != ETK_Typename) {
    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
    if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false,
                                              TagLocation, Id)) {
      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
        << Id
        << FixItHint::CreateReplacement(SourceRange(TagLocation),
                                        TD->getKindName());
      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
    }
  }
}

return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(KeywordLoc,
                                                                  Keyword,
                                                                QualifierLoc,
                                                                  T);
1352}

1354TemplateName TemplateInstantiator::TransformTemplateName(
  CXXScopeSpec &SS, TemplateName Name, SourceLocation NameLoc,
  QualType ObjectType, NamedDecl *FirstQualifierInScope,
  bool AllowInjectedClassName) {
if (TemplateTemplateParmDecl *TTP
     = dyn_cast_or_null<TemplateTemplateParmDecl>(Name.getAsTemplateDecl())) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return Name;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TemplateArgs.isRewrite()) {
      // We're rewriting the template parameter as a reference to another
      // template parameter.
      if (Arg.getKind() == TemplateArgument::Pack) {
        assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
               "unexpected pack arguments in template rewrite")((void)0);
        Arg = Arg.pack_begin()->getPackExpansionPattern();
      }
      assert(Arg.getKind() == TemplateArgument::Template &&((void)0)
             "unexpected nontype template argument kind in template rewrite")((void)0);
      return Arg.getAsTemplate();
    }

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);

      if (getSema().ArgumentPackSubstitutionIndex == -1) {
        // We have the template argument pack to substitute, but we're not
        // actually expanding the enclosing pack expansion yet. So, just
        // keep the entire argument pack.
        return getSema().Context.getSubstTemplateTemplateParmPack(TTP, Arg);
      }

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && "Null template template argument")((void)0);
    assert(!Template.getAsQualifiedTemplateName() &&((void)0)
           "template decl to substitute is qualified?")((void)0);

    Template = getSema().Context.getSubstTemplateTemplateParm(TTP, Template);
    return Template;
  }
}

if (SubstTemplateTemplateParmPackStorage *SubstPack
    = Name.getAsSubstTemplateTemplateParmPack()) {
  if (getSema().ArgumentPackSubstitutionIndex == -1)
    return Name;

  TemplateArgument Arg = SubstPack->getArgumentPack();
  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  return Arg.getAsTemplate().getNameToSubstitute();
}

return inherited::TransformTemplateName(SS, Name, NameLoc, ObjectType,
                                        FirstQualifierInScope,
                                        AllowInjectedClassName);
1421}

1423ExprResult
1424TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
if (!E->isTypeDependent())
  return E;

return getSema().BuildPredefinedExpr(E->getLocation(), E->getIdentKind());
1429}

1431ExprResult
1432TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
                                             NonTypeTemplateParmDecl *NTTP) {
// If the corresponding template argument is NULL or non-existent, it's
// because we are performing instantiation from explicitly-specified
// template arguments in a function template, but there were some
// arguments left unspecified.
if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
                                      NTTP->getPosition()))
  return E;

TemplateArgument Arg = TemplateArgs(NTTP->getDepth(), NTTP->getPosition());

if (TemplateArgs.isRewrite()) {
  // We're rewriting the template parameter as a reference to another
  // template parameter.
  if (Arg.getKind() == TemplateArgument::Pack) {
    assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
           "unexpected pack arguments in template rewrite")((void)0);
    Arg = Arg.pack_begin()->getPackExpansionPattern();
  }
  assert(Arg.getKind() == TemplateArgument::Expression &&((void)0)
         "unexpected nontype template argument kind in template rewrite")((void)0);
  // FIXME: This can lead to the same subexpression appearing multiple times
  // in a complete expression.
  return Arg.getAsExpr();
}

if (NTTP->isParameterPack()) {
  assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
         "Missing argument pack")((void)0);

  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    // We have an argument pack, but we can't select a particular argument
    // out of it yet. Therefore, we'll build an expression to hold on to that
    // argument pack.
    QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
                                            E->getLocation(),
                                            NTTP->getDeclName());
    if (TargetType.isNull())
      return ExprError();

    QualType ExprType = TargetType.getNonLValueExprType(SemaRef.Context);
    if (TargetType->isRecordType())
      ExprType.addConst();

    return new (SemaRef.Context) SubstNonTypeTemplateParmPackExpr(
        ExprType, TargetType->isReferenceType() ? VK_LValue : VK_PRValue,
        NTTP, E->getLocation(), Arg);
  }

  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
}

return transformNonTypeTemplateParmRef(NTTP, E->getLocation(), Arg);
1486}

1488const LoopHintAttr *
1489TemplateInstantiator::TransformLoopHintAttr(const LoopHintAttr *LH) {
Expr *TransformedExpr = getDerived().TransformExpr(LH->getValue()).get();

if (TransformedExpr == LH->getValue())
  return LH;

// Generate error if there is a problem with the value.
if (getSema().CheckLoopHintExpr(TransformedExpr, LH->getLocation()))
  return LH;

// Create new LoopHintValueAttr with integral expression in place of the
// non-type template parameter.
return LoopHintAttr::CreateImplicit(getSema().Context, LH->getOption(),
                                    LH->getState(), TransformedExpr, *LH);
1503}

1505ExprResult TemplateInstantiator::transformNonTypeTemplateParmRef(
                                               NonTypeTemplateParmDecl *parm,
                                               SourceLocation loc,
                                               TemplateArgument arg) {
ExprResult result;

// Determine the substituted parameter type. We can usually infer this from
// the template argument, but not always.
auto SubstParamType = [&] {
  QualType T;
  if (parm->isExpandedParameterPack())
    T = parm->getExpansionType(SemaRef.ArgumentPackSubstitutionIndex);
  else
    T = parm->getType();
  if (parm->isParameterPack() && isa<PackExpansionType>(T))
    T = cast<PackExpansionType>(T)->getPattern();
  return SemaRef.SubstType(T, TemplateArgs, loc, parm->getDeclName());
};

bool refParam = false;

// The template argument itself might be an expression, in which case we just
// return that expression. This happens when substituting into an alias
// template.
if (arg.getKind() == TemplateArgument::Expression) {
  Expr *argExpr = arg.getAsExpr();
  result = argExpr;
  if (argExpr->isLValue()) {
    if (argExpr->getType()->isRecordType()) {
      // Check whether the parameter was actually a reference.
      QualType paramType = SubstParamType();
      if (paramType.isNull())
        return ExprError();
      refParam = paramType->isReferenceType();
    } else {
      refParam = true;
    }
  }
} else if (arg.getKind() == TemplateArgument::Declaration ||
           arg.getKind() == TemplateArgument::NullPtr) {
  ValueDecl *VD;
  if (arg.getKind() == TemplateArgument::Declaration) {
    VD = arg.getAsDecl();

    // Find the instantiation of the template argument.  This is
    // required for nested templates.
    VD = cast_or_null<ValueDecl>(
           getSema().FindInstantiatedDecl(loc, VD, TemplateArgs));
    if (!VD)
      return ExprError();
  } else {
    // Propagate NULL template argument.
    VD = nullptr;
  }

  QualType paramType = VD ? arg.getParamTypeForDecl() : arg.getNullPtrType();
  assert(!paramType.isNull() && "type substitution failed for param type")((void)0);
  assert(!paramType->isDependentType() && "param type still dependent")((void)0);
  result = SemaRef.BuildExpressionFromDeclTemplateArgument(arg, paramType, loc);
  refParam = paramType->isReferenceType();
} else {
  result = SemaRef.BuildExpressionFromIntegralTemplateArgument(arg, loc);
  assert(result.isInvalid() ||((void)0)
         SemaRef.Context.hasSameType(result.get()->getType(),((void)0)
                                     arg.getIntegralType()))((void)0);
}

if (result.isInvalid())
  return ExprError();

Expr *resultExpr = result.get();
return new (SemaRef.Context) SubstNonTypeTemplateParmExpr(
    resultExpr->getType(), resultExpr->getValueKind(), loc, parm, refParam,
    resultExpr);
1579}

1581ExprResult
1582TemplateInstantiator::TransformSubstNonTypeTemplateParmPackExpr(
                                        SubstNonTypeTemplateParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  return E;
}

TemplateArgument Arg = E->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
return transformNonTypeTemplateParmRef(E->getParameterPack(),
                                       E->getParameterPackLocation(),
                                       Arg);
1594}

1596ExprResult
1597TemplateInstantiator::TransformSubstNonTypeTemplateParmExpr(
                                        SubstNonTypeTemplateParmExpr *E) {
ExprResult SubstReplacement = E->getReplacement();
if (!isa<ConstantExpr>(SubstReplacement.get()))
  SubstReplacement = TransformExpr(E->getReplacement());
if (SubstReplacement.isInvalid())
  return true;
QualType SubstType = TransformType(E->getParameterType(getSema().Context));
if (SubstType.isNull())
  return true;
// The type may have been previously dependent and not now, which means we
// might have to implicit cast the argument to the new type, for example:
// template<auto T, decltype(T) U>
// concept C = sizeof(U) == 4;
// void foo() requires C<2, 'a'> { }
// When normalizing foo(), we first form the normalized constraints of C:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=DeclRef(U),
//                                           Type=decltype(T)))
// Then we substitute T = 2, U = 'a' into the parameter mapping, and need to
// produce:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=ImpCast(
//                                               decltype(2),
//                                               SubstNTTPE(Param=U, Expr='a',
//                                                          Type=char)),
//                                           Type=decltype(2)))
// The call to CheckTemplateArgument here produces the ImpCast.
TemplateArgument Converted;
if (SemaRef.CheckTemplateArgument(E->getParameter(), SubstType,
                                  SubstReplacement.get(),
                                  Converted).isInvalid())
  return true;
return transformNonTypeTemplateParmRef(E->getParameter(),
                                       E->getExprLoc(), Converted);
1634}

1636ExprResult TemplateInstantiator::RebuildVarDeclRefExpr(VarDecl *PD,
                                                     SourceLocation Loc) {
DeclarationNameInfo NameInfo(PD->getDeclName(), Loc);
return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD);
1640}

1642ExprResult
1643TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex != -1) {
  // We can expand this parameter pack now.
  VarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
  VarDecl *VD = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), D));
  if (!VD)
    return ExprError();
  return RebuildVarDeclRefExpr(VD, E->getExprLoc());
}

QualType T = TransformType(E->getType());
if (T.isNull())
  return ExprError();

// Transform each of the parameter expansions into the corresponding
// parameters in the instantiation of the function decl.
SmallVector<VarDecl *, 8> Vars;
Vars.reserve(E->getNumExpansions());
for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end();
     I != End; ++I) {
  VarDecl *D = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), *I));
  if (!D)
    return ExprError();
  Vars.push_back(D);
}

auto *PackExpr =
    FunctionParmPackExpr::Create(getSema().Context, T, E->getParameterPack(),
                                 E->getParameterPackLocation(), Vars);
getSema().MarkFunctionParmPackReferenced(PackExpr);
return PackExpr;
1674}

1676ExprResult
1677TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E,
                                                     VarDecl *PD) {
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
  = getSema().CurrentInstantiationScope->findInstantiationOf(PD);
assert(Found && "no instantiation for parameter pack")((void)0);

Decl *TransformedDecl;
if (DeclArgumentPack *Pack = Found->dyn_cast<DeclArgumentPack *>()) {
  // If this is a reference to a function parameter pack which we can
  // substitute but can't yet expand, build a FunctionParmPackExpr for it.
  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    QualType T = TransformType(E->getType());
    if (T.isNull())
      return ExprError();
    auto *PackExpr = FunctionParmPackExpr::Create(getSema().Context, T, PD,
                                                  E->getExprLoc(), *Pack);
    getSema().MarkFunctionParmPackReferenced(PackExpr);
    return PackExpr;
  }

  TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];
} else {
  TransformedDecl = Found->get<Decl*>();
}

// We have either an unexpanded pack or a specific expansion.
return RebuildVarDeclRefExpr(cast<VarDecl>(TransformedDecl), E->getExprLoc());
1705}

1707ExprResult
1708TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
NamedDecl *D = E->getDecl();

// Handle references to non-type template parameters and non-type template
// parameter packs.
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
  if (NTTP->getDepth() < TemplateArgs.getNumLevels())
    return TransformTemplateParmRefExpr(E, NTTP);

  // We have a non-type template parameter that isn't fully substituted;
  // FindInstantiatedDecl will find it in the local instantiation scope.
}

// Handle references to function parameter packs.
if (VarDecl *PD = dyn_cast<VarDecl>(D))
  if (PD->isParameterPack())
    return TransformFunctionParmPackRefExpr(E, PD);

return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
1727}

1729ExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
  CXXDefaultArgExpr *E) {
assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->((void)0)
           getDescribedFunctionTemplate() &&((void)0)
       "Default arg expressions are never formed in dependent cases.")((void)0);
return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
                         cast<FunctionDecl>(E->getParam()->getDeclContext()),
                                      E->getParam());
1737}

1739template<typename Fn>
1740QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB,
                               FunctionProtoTypeLoc TL,
                               CXXRecordDecl *ThisContext,
                               Qualifiers ThisTypeQuals,
                               Fn TransformExceptionSpec) {
// We need a local instantiation scope for this function prototype.
LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
return inherited::TransformFunctionProtoType(
    TLB, TL, ThisContext, ThisTypeQuals, TransformExceptionSpec);
1749}

1751ParmVarDecl *
1752TemplateInstantiator::TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                               int indexAdjustment,
                                             Optional<unsigned> NumExpansions,
                                               bool ExpectParameterPack) {
auto NewParm =
    SemaRef.SubstParmVarDecl(OldParm, TemplateArgs, indexAdjustment,
                             NumExpansions, ExpectParameterPack);
if (NewParm && SemaRef.getLangOpts().OpenCL)
  SemaRef.deduceOpenCLAddressSpace(NewParm);
return NewParm;
1762}

1764QualType
1765TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                              TemplateTypeParmTypeLoc TL) {
const TemplateTypeParmType *T = TL.getTypePtr();
if (T->getDepth() < TemplateArgs.getNumLevels()) {
  // Replace the template type parameter with its corresponding
  // template argument.

  // If the corresponding template argument is NULL or doesn't exist, it's
  // because we are performing instantiation from explicitly-specified
  // template arguments in a function template class, but there were some
  // arguments left unspecified.
  if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
    TemplateTypeParmTypeLoc NewTL
      = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
    NewTL.setNameLoc(TL.getNameLoc());
    return TL.getType();
  }

  TemplateArgument Arg = TemplateArgs(T->getDepth(), T->getIndex());

  if (TemplateArgs.isRewrite()) {
    // We're rewriting the template parameter as a reference to another
    // template parameter.
    if (Arg.getKind() == TemplateArgument::Pack) {
      assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
             "unexpected pack arguments in template rewrite")((void)0);
      Arg = Arg.pack_begin()->getPackExpansionPattern();
    }
    assert(Arg.getKind() == TemplateArgument::Type &&((void)0)
           "unexpected nontype template argument kind in template rewrite")((void)0);
    QualType NewT = Arg.getAsType();
    assert(isa<TemplateTypeParmType>(NewT) &&((void)0)
           "type parm not rewritten to type parm")((void)0);
    auto NewTL = TLB.push<TemplateTypeParmTypeLoc>(NewT);
    NewTL.setNameLoc(TL.getNameLoc());
    return NewT;
  }

  if (T->isParameterPack()) {
    assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
           "Missing argument pack")((void)0);

    if (getSema().ArgumentPackSubstitutionIndex == -1) {
      // We have the template argument pack, but we're not expanding the
      // enclosing pack expansion yet. Just save the template argument
      // pack for later substitution.
      QualType Result
        = getSema().Context.getSubstTemplateTypeParmPackType(T, Arg);
      SubstTemplateTypeParmPackTypeLoc NewTL
        = TLB.push<SubstTemplateTypeParmPackTypeLoc>(Result);
      NewTL.setNameLoc(TL.getNameLoc());
      return Result;
    }

    Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  }

  assert(Arg.getKind() == TemplateArgument::Type &&((void)0)
         "Template argument kind mismatch")((void)0);

  QualType Replacement = Arg.getAsType();

  // TODO: only do this uniquing once, at the start of instantiation.
  QualType Result
    = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
  SubstTemplateTypeParmTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
  NewTL.setNameLoc(TL.getNameLoc());
  return Result;
}

// The template type parameter comes from an inner template (e.g.,
// the template parameter list of a member template inside the
// template we are instantiating). Create a new template type
// parameter with the template "level" reduced by one.
TemplateTypeParmDecl *NewTTPDecl = nullptr;
if (TemplateTypeParmDecl *OldTTPDecl = T->getDecl())
  NewTTPDecl = cast_or_null<TemplateTypeParmDecl>(
                                TransformDecl(TL.getNameLoc(), OldTTPDecl));

QualType Result = getSema().Context.getTemplateTypeParmType(
    T->getDepth() - TemplateArgs.getNumSubstitutedLevels(), T->getIndex(),
    T->isParameterPack(), NewTTPDecl);
TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1851}

1853QualType
1854TemplateInstantiator::TransformSubstTemplateTypeParmPackType(
                                                          TypeLocBuilder &TLB,
                                       SubstTemplateTypeParmPackTypeLoc TL) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  SubstTemplateTypeParmPackTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmPackTypeLoc>(TL.getType());
  NewTL.setNameLoc(TL.getNameLoc());
  return TL.getType();
}

TemplateArgument Arg = TL.getTypePtr()->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
QualType Result = Arg.getAsType();

Result = getSema().Context.getSubstTemplateTypeParmType(
                                    TL.getTypePtr()->getReplacedParameter(),
                                                        Result);
SubstTemplateTypeParmTypeLoc NewTL
  = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1876}

1878template<typename EntityPrinter>
1879static concepts::Requirement::SubstitutionDiagnostic *
1880createSubstDiag(Sema &S, TemplateDeductionInfo &Info, EntityPrinter Printer) {
SmallString<128> Message;
SourceLocation ErrorLoc;
if (Info.hasSFINAEDiagnostic()) {
  PartialDiagnosticAt PDA(SourceLocation(),
                          PartialDiagnostic::NullDiagnostic{});
  Info.takeSFINAEDiagnostic(PDA);
  PDA.second.EmitToString(S.getDiagnostics(), Message);
  ErrorLoc = PDA.first;
} else {
  ErrorLoc = Info.getLocation();
}
char *MessageBuf = new (S.Context) char[Message.size()];
std::copy(Message.begin(), Message.end(), MessageBuf);
SmallString<128> Entity;
llvm::raw_svector_ostream OS(Entity);
Printer(OS);
char *EntityBuf = new (S.Context) char[Entity.size()];
std::copy(Entity.begin(), Entity.end(), EntityBuf);
return new (S.Context) concepts::Requirement::SubstitutionDiagnostic{
    StringRef(EntityBuf, Entity.size()), ErrorLoc,
    StringRef(MessageBuf, Message.size())};
1902}

1904concepts::TypeRequirement *
1905TemplateInstantiator::TransformTypeRequirement(concepts::TypeRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildTypeRequirement(
            Req->getSubstitutionDiagnostic());
  return Req;
}

Sema::SFINAETrap Trap(SemaRef);
TemplateDeductionInfo Info(Req->getType()->getTypeLoc().getBeginLoc());
Sema::InstantiatingTemplate TypeInst(SemaRef,
    Req->getType()->getTypeLoc().getBeginLoc(), Req, Info,
    Req->getType()->getTypeLoc().getSourceRange());
if (TypeInst.isInvalid())
  return nullptr;
TypeSourceInfo *TransType = TransformType(Req->getType());
if (!TransType || Trap.hasErrorOccurred())
  return RebuildTypeRequirement(createSubstDiag(SemaRef, Info,
      [&] (llvm::raw_ostream& OS) {
          Req->getType()->getType().print(OS, SemaRef.getPrintingPolicy());
      }));
return RebuildTypeRequirement(TransType);
1929}

1931concepts::ExprRequirement *
1932TemplateInstantiator::TransformExprRequirement(concepts::ExprRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;

Sema::SFINAETrap Trap(SemaRef);

llvm::PointerUnion<Expr *, concepts::Requirement::SubstitutionDiagnostic *>
    TransExpr;
if (Req->isExprSubstitutionFailure())
  TransExpr = Req->getExprSubstitutionDiagnostic();
else {
  Expr *E = Req->getExpr();
  TemplateDeductionInfo Info(E->getBeginLoc());
  Sema::InstantiatingTemplate ExprInst(SemaRef, E->getBeginLoc(), Req, Info,
                                       E->getSourceRange());
  if (ExprInst.isInvalid())
    return nullptr;
  ExprResult TransExprRes = TransformExpr(E);
  if (TransExprRes.isInvalid() || Trap.hasErrorOccurred())
    TransExpr = createSubstDiag(SemaRef, Info, [&](llvm::raw_ostream &OS) {
      E->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
    });
  else
    TransExpr = TransExprRes.get();
}

llvm::Optional<concepts::ExprRequirement::ReturnTypeRequirement> TransRetReq;
const auto &RetReq = Req->getReturnTypeRequirement();
if (RetReq.isEmpty())
  TransRetReq.emplace();
else if (RetReq.isSubstitutionFailure())
  TransRetReq.emplace(RetReq.getSubstitutionDiagnostic());
else if (RetReq.isTypeConstraint()) {
  TemplateParameterList *OrigTPL =
      RetReq.getTypeConstraintTemplateParameterList();
  TemplateDeductionInfo Info(OrigTPL->getTemplateLoc());
  Sema::InstantiatingTemplate TPLInst(SemaRef, OrigTPL->getTemplateLoc(),
                                      Req, Info, OrigTPL->getSourceRange());
  if (TPLInst.isInvalid())
    return nullptr;
  TemplateParameterList *TPL =
      TransformTemplateParameterList(OrigTPL);
  if (!TPL)
    TransRetReq.emplace(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            RetReq.getTypeConstraint()->getImmediatelyDeclaredConstraint()
                ->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
        }));
  else {
    TPLInst.Clear();
    TransRetReq.emplace(TPL);
  }
}
assert(TransRetReq.hasValue() &&((void)0)
       "All code paths leading here must set TransRetReq")((void)0);
if (Expr *E = TransExpr.dyn_cast<Expr *>())
  return RebuildExprRequirement(E, Req->isSimple(), Req->getNoexceptLoc(),
                                std::move(*TransRetReq));
return RebuildExprRequirement(
    TransExpr.get<concepts::Requirement::SubstitutionDiagnostic *>(),
    Req->isSimple(), Req->getNoexceptLoc(), std::move(*TransRetReq));
1993}

1995concepts::NestedRequirement *
1996TemplateInstantiator::TransformNestedRequirement(
  concepts::NestedRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildNestedRequirement(
        Req->getSubstitutionDiagnostic());
  return Req;
}
Sema::InstantiatingTemplate ReqInst(SemaRef,
    Req->getConstraintExpr()->getBeginLoc(), Req,
    Sema::InstantiatingTemplate::ConstraintsCheck{},
    Req->getConstraintExpr()->getSourceRange());

ExprResult TransConstraint;
TemplateDeductionInfo Info(Req->getConstraintExpr()->getBeginLoc());
{
  EnterExpressionEvaluationContext ContextRAII(
      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  Sema::SFINAETrap Trap(SemaRef);
  Sema::InstantiatingTemplate ConstrInst(SemaRef,
      Req->getConstraintExpr()->getBeginLoc(), Req, Info,
      Req->getConstraintExpr()->getSourceRange());
  if (ConstrInst.isInvalid())
    return nullptr;
  TransConstraint = TransformExpr(Req->getConstraintExpr());
  if (TransConstraint.isInvalid() || Trap.hasErrorOccurred())
    return RebuildNestedRequirement(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            Req->getConstraintExpr()->printPretty(OS, nullptr,
                                                  SemaRef.getPrintingPolicy());
        }));
}
return RebuildNestedRequirement(TransConstraint.get());
2031}


2034/// Perform substitution on the type T with a given set of template
2035/// arguments.
2036///
2037/// This routine substitutes the given template arguments into the
2038/// type T and produces the instantiated type.
2039///
2040/// \param T the type into which the template arguments will be
2041/// substituted. If this type is not dependent, it will be returned
2042/// immediately.
2043///
2044/// \param Args the template arguments that will be
2045/// substituted for the top-level template parameters within T.
2046///
2047/// \param Loc the location in the source code where this substitution
2048/// is being performed. It will typically be the location of the
2049/// declarator (if we're instantiating the type of some declaration)
2050/// or the location of the type in the source code (if, e.g., we're
2051/// instantiating the type of a cast expression).
2052///
2053/// \param Entity the name of the entity associated with a declaration
2054/// being instantiated (if any). May be empty to indicate that there
2055/// is no such entity (if, e.g., this is a type that occurs as part of
2056/// a cast expression) or that the entity has no name (e.g., an
2057/// unnamed function parameter).
2058///
2059/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
2060/// acceptable as the top level type of the result.
2061///
2062/// \returns If the instantiation succeeds, the instantiated
2063/// type. Otherwise, produces diagnostics and returns a NULL type.
2064TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              bool AllowDeducedTST) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (!T->getType()->isInstantiationDependentType() &&
    !T->getType()->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
return AllowDeducedTST ? Instantiator.TransformTypeWithDeducedTST(T)
                       : Instantiator.TransformType(T);
2080}

2082TypeSourceInfo *Sema::SubstType(TypeLoc TL,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (TL.getType().isNull())
  return nullptr;

if (!TL.getType()->isInstantiationDependentType() &&
    !TL.getType()->isVariablyModifiedType()) {
  // FIXME: Make a copy of the TypeLoc data here, so that we can
  // return a new TypeSourceInfo. Inefficient!
  TypeLocBuilder TLB;
  TLB.pushFullCopy(TL);
  return TLB.getTypeSourceInfo(Context, TL.getType());
}

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
TypeLocBuilder TLB;
TLB.reserve(TL.getFullDataSize());
QualType Result = Instantiator.TransformType(TLB, TL);
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2110}

2112/// Deprecated form of the above.
2113QualType Sema::SubstType(QualType T,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc, DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

// If T is not a dependent type or a variably-modified type, there
// is nothing to do.
if (!T->isInstantiationDependentType() && !T->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
return Instantiator.TransformType(T);
2127}

2129static bool NeedsInstantiationAsFunctionType(TypeSourceInfo *T) {
if (T->getType()->isInstantiationDependentType() ||
    T->getType()->isVariablyModifiedType())
  return true;

TypeLoc TL = T->getTypeLoc().IgnoreParens();
if (!TL.getAs<FunctionProtoTypeLoc>())
  return false;

FunctionProtoTypeLoc FP = TL.castAs<FunctionProtoTypeLoc>();
for (ParmVarDecl *P : FP.getParams()) {
  // This must be synthesized from a typedef.
  if (!P) continue;

  // If there are any parameters, a new TypeSourceInfo that refers to the
  // instantiated parameters must be built.
  return true;
}

return false;
2149}

2151/// A form of SubstType intended specifically for instantiating the
2152/// type of a FunctionDecl.  Its purpose is solely to force the
2153/// instantiation of default-argument expressions and to avoid
2154/// instantiating an exception-specification.
2155TypeSourceInfo *Sema::SubstFunctionDeclType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              CXXRecordDecl *ThisContext,
                              Qualifiers ThisTypeQuals) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (!NeedsInstantiationAsFunctionType(T))
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);

TypeLocBuilder TLB;

TypeLoc TL = T->getTypeLoc();
TLB.reserve(TL.getFullDataSize());

QualType Result;

if (FunctionProtoTypeLoc Proto =
        TL.IgnoreParens().getAs<FunctionProtoTypeLoc>()) {
  // Instantiate the type, other than its exception specification. The
  // exception specification is instantiated in InitFunctionInstantiation
  // once we've built the FunctionDecl.
  // FIXME: Set the exception specification to EST_Uninstantiated here,
  // instead of rebuilding the function type again later.
  Result = Instantiator.TransformFunctionProtoType(
      TLB, Proto, ThisContext, ThisTypeQuals,
      [](FunctionProtoType::ExceptionSpecInfo &ESI,
         bool &Changed) { return false; });
} else {
  Result = Instantiator.TransformType(TLB, TL);
}
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2195}

2197bool Sema::SubstExceptionSpec(SourceLocation Loc,
                            FunctionProtoType::ExceptionSpecInfo &ESI,
                            SmallVectorImpl<QualType> &ExceptionStorage,
                            const MultiLevelTemplateArgumentList &Args) {
assert(ESI.Type != EST_Uninstantiated)((void)0);

bool Changed = false;
TemplateInstantiator Instantiator(*this, Args, Loc, DeclarationName());
return Instantiator.TransformExceptionSpec(Loc, ESI, ExceptionStorage,
                                           Changed);
2207}

2209void Sema::SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                            const MultiLevelTemplateArgumentList &Args) {
FunctionProtoType::ExceptionSpecInfo ESI =
    Proto->getExtProtoInfo().ExceptionSpec;

SmallVector<QualType, 4> ExceptionStorage;
if (SubstExceptionSpec(New->getTypeSourceInfo()->getTypeLoc().getEndLoc(),
                       ESI, ExceptionStorage, Args))
  // On error, recover by dropping the exception specification.
  ESI.Type = EST_None;

UpdateExceptionSpec(New, ESI);
2221}

2223namespace {

struct GetContainedInventedTypeParmVisitor :
  public TypeVisitor<GetContainedInventedTypeParmVisitor,
                     TemplateTypeParmDecl *> {
  using TypeVisitor<GetContainedInventedTypeParmVisitor,
                    TemplateTypeParmDecl *>::Visit;

  TemplateTypeParmDecl *Visit(QualType T) {
    if (T.isNull())
      return nullptr;
    return Visit(T.getTypePtr());
  }
  // The deduced type itself.
  TemplateTypeParmDecl *VisitTemplateTypeParmType(
      const TemplateTypeParmType *T) {
    if (!T->getDecl() || !T->getDecl()->isImplicit())
      return nullptr;
    return T->getDecl();
  }

  // Only these types can contain 'auto' types, and subsequently be replaced
  // by references to invented parameters.

  TemplateTypeParmDecl *VisitElaboratedType(const ElaboratedType *T) {
    return Visit(T->getNamedType());
  }

  TemplateTypeParmDecl *VisitPointerType(const PointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitBlockPointerType(const BlockPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitReferenceType(const ReferenceType *T) {
    return Visit(T->getPointeeTypeAsWritten());
  }

  TemplateTypeParmDecl *VisitMemberPointerType(const MemberPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitArrayType(const ArrayType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitDependentSizedExtVectorType(
    const DependentSizedExtVectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitVectorType(const VectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitFunctionProtoType(const FunctionProtoType *T) {
    return VisitFunctionType(T);
  }

  TemplateTypeParmDecl *VisitFunctionType(const FunctionType *T) {
    return Visit(T->getReturnType());
  }

  TemplateTypeParmDecl *VisitParenType(const ParenType *T) {
    return Visit(T->getInnerType());
  }

  TemplateTypeParmDecl *VisitAttributedType(const AttributedType *T) {
    return Visit(T->getModifiedType());
  }

  TemplateTypeParmDecl *VisitMacroQualifiedType(const MacroQualifiedType *T) {
    return Visit(T->getUnderlyingType());
  }

  TemplateTypeParmDecl *VisitAdjustedType(const AdjustedType *T) {
    return Visit(T->getOriginalType());
  }

  TemplateTypeParmDecl *VisitPackExpansionType(const PackExpansionType *T) {
    return Visit(T->getPattern());
  }
};

2309} // namespace

2311ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                  int indexAdjustment,
                                  Optional<unsigned> NumExpansions,
                                  bool ExpectParameterPack) {
TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo();
TypeSourceInfo *NewDI = nullptr;

TypeLoc OldTL = OldDI->getTypeLoc();
if (PackExpansionTypeLoc ExpansionTL = OldTL.getAs<PackExpansionTypeLoc>()) {

  // We have a function parameter pack. Substitute into the pattern of the
  // expansion.
  NewDI = SubstType(ExpansionTL.getPatternLoc(), TemplateArgs,
                    OldParm->getLocation(), OldParm->getDeclName());
  if (!NewDI)
    return nullptr;

  if (NewDI->getType()->containsUnexpandedParameterPack()) {
    // We still have unexpanded parameter packs, which means that
    // our function parameter is still a function parameter pack.
    // Therefore, make its type a pack expansion type.
    NewDI = CheckPackExpansion(NewDI, ExpansionTL.getEllipsisLoc(),
                               NumExpansions);
  } else if (ExpectParameterPack) {
    // We expected to get a parameter pack but didn't (because the type
    // itself is not a pack expansion type), so complain. This can occur when
    // the substitution goes through an alias template that "loses" the
    // pack expansion.
    Diag(OldParm->getLocation(),
         diag::err_function_parameter_pack_without_parameter_packs)
      << NewDI->getType();
    return nullptr;
  }
} else {
  NewDI = SubstType(OldDI, TemplateArgs, OldParm->getLocation(),
                    OldParm->getDeclName());
}

if (!NewDI)
  return nullptr;

if (NewDI->getType()->isVoidType()) {
  Diag(OldParm->getLocation(), diag::err_param_with_void_type);
  return nullptr;
}

// In abbreviated templates, TemplateTypeParmDecls with possible
// TypeConstraints are created when the parameter list is originally parsed.
// The TypeConstraints can therefore reference other functions parameters in
// the abbreviated function template, which is why we must instantiate them
// here, when the instantiated versions of those referenced parameters are in
// scope.
if (TemplateTypeParmDecl *TTP =
        GetContainedInventedTypeParmVisitor().Visit(OldDI->getType())) {
  if (const TypeConstraint *TC = TTP->getTypeConstraint()) {
    auto *Inst = cast_or_null<TemplateTypeParmDecl>(
        FindInstantiatedDecl(TTP->getLocation(), TTP, TemplateArgs));
    // We will first get here when instantiating the abbreviated function
    // template's described function, but we might also get here later.
    // Make sure we do not instantiate the TypeConstraint more than once.
    if (Inst && !Inst->getTypeConstraint()) {
      // TODO: Concepts: do not instantiate the constraint (delayed constraint
      // substitution)
      const ASTTemplateArgumentListInfo *TemplArgInfo
        = TC->getTemplateArgsAsWritten();
      TemplateArgumentListInfo InstArgs;

      if (TemplArgInfo) {
        InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
        InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
        if (Subst(TemplArgInfo->getTemplateArgs(),
                  TemplArgInfo->NumTemplateArgs, InstArgs, TemplateArgs))
          return nullptr;
      }
      if (AttachTypeConstraint(
              TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
              TC->getNamedConcept(), TemplArgInfo ? &InstArgs : nullptr, Inst,
              TTP->isParameterPack()
                  ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
                        ->getEllipsisLoc()
                  : SourceLocation()))
        return nullptr;
    }
  }
}

ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(),
                                      OldParm->getInnerLocStart(),
                                      OldParm->getLocation(),
                                      OldParm->getIdentifier(),
                                      NewDI->getType(), NewDI,
                                      OldParm->getStorageClass());
if (!NewParm)
  return nullptr;

// Mark the (new) default argument as uninstantiated (if any).
if (OldParm->hasUninstantiatedDefaultArg()) {
  Expr *Arg = OldParm->getUninstantiatedDefaultArg();
  NewParm->setUninstantiatedDefaultArg(Arg);
} else if (OldParm->hasUnparsedDefaultArg()) {
  NewParm->setUnparsedDefaultArg();
  UnparsedDefaultArgInstantiations[OldParm].push_back(NewParm);
} else if (Expr *Arg = OldParm->getDefaultArg()) {
  FunctionDecl *OwningFunc = cast<FunctionDecl>(OldParm->getDeclContext());
  if (OwningFunc->isInLocalScopeForInstantiation()) {
    // Instantiate default arguments for methods of local classes (DR1484)
    // and non-defining declarations.
    Sema::ContextRAII SavedContext(*this, OwningFunc);
    LocalInstantiationScope Local(*this, true);
    ExprResult NewArg = SubstExpr(Arg, TemplateArgs);
    if (NewArg.isUsable()) {
      // It would be nice if we still had this.
      SourceLocation EqualLoc = NewArg.get()->getBeginLoc();
      ExprResult Result =
          ConvertParamDefaultArgument(NewParm, NewArg.get(), EqualLoc);
      if (Result.isInvalid())
        return nullptr;

      SetParamDefaultArgument(NewParm, Result.getAs<Expr>(), EqualLoc);
    }
  } else {
    // FIXME: if we non-lazily instantiated non-dependent default args for
    // non-dependent parameter types we could remove a bunch of duplicate
    // conversion warnings for such arguments.
    NewParm->setUninstantiatedDefaultArg(Arg);
  }
}

NewParm->setHasInheritedDefaultArg(OldParm->hasInheritedDefaultArg());

if (OldParm->isParameterPack() && !NewParm->isParameterPack()) {
  // Add the new parameter to the instantiated parameter pack.
  CurrentInstantiationScope->InstantiatedLocalPackArg(OldParm, NewParm);
} else {
  // Introduce an Old -> New mapping
  CurrentInstantiationScope->InstantiatedLocal(OldParm, NewParm);
}

// FIXME: OldParm may come from a FunctionProtoType, in which case CurContext
// can be anything, is this right ?
NewParm->setDeclContext(CurContext);

NewParm->setScopeInfo(OldParm->getFunctionScopeDepth(),
                      OldParm->getFunctionScopeIndex() + indexAdjustment);

InstantiateAttrs(TemplateArgs, OldParm, NewParm);

return NewParm;
2460}

2462/// Substitute the given template arguments into the given set of
2463/// parameters, producing the set of parameter types that would be generated
2464/// from such a substitution.
2465bool Sema::SubstParmTypes(
  SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
  const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
  const MultiLevelTemplateArgumentList &TemplateArgs,
  SmallVectorImpl<QualType> &ParamTypes,
  SmallVectorImpl<ParmVarDecl *> *OutParams,
  ExtParameterInfoBuilder &ParamInfos) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
                                  DeclarationName());
return Instantiator.TransformFunctionTypeParams(
    Loc, Params, nullptr, ExtParamInfos, ParamTypes, OutParams, ParamInfos);
2480}

2482/// Perform substitution on the base class specifiers of the
2483/// given class template specialization.
2484///
2485/// Produces a diagnostic and returns true on error, returns false and
2486/// attaches the instantiated base classes to the class template
2487/// specialization if successful.
2488bool
2489Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                        CXXRecordDecl *Pattern,
                        const MultiLevelTemplateArgumentList &TemplateArgs) {
bool Invalid = false;
SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
for (const auto &Base : Pattern->bases()) {
  if (!Base.getType()->isDependentType()) {
    if (const CXXRecordDecl *RD = Base.getType()->getAsCXXRecordDecl()) {
      if (RD->isInvalidDecl())
        Instantiation->setInvalidDecl();
    }
    InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(Base));
    continue;
  }

  SourceLocation EllipsisLoc;
  TypeSourceInfo *BaseTypeLoc;
  if (Base.isPackExpansion()) {
    // This is a pack expansion. See whether we should expand it now, or
    // wait until later.
    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
    collectUnexpandedParameterPacks(Base.getTypeSourceInfo()->getTypeLoc(),
                                    Unexpanded);
    bool ShouldExpand = false;
    bool RetainExpansion = false;
    Optional<unsigned> NumExpansions;
    if (CheckParameterPacksForExpansion(Base.getEllipsisLoc(),
                                        Base.getSourceRange(),
                                        Unexpanded,
                                        TemplateArgs, ShouldExpand,
                                        RetainExpansion,
                                        NumExpansions)) {
      Invalid = true;
      continue;
    }

    // If we should expand this pack expansion now, do so.
    if (ShouldExpand) {
      for (unsigned I = 0; I != *NumExpansions; ++I) {
          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);

        TypeSourceInfo *BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                                                TemplateArgs,
                                            Base.getSourceRange().getBegin(),
                                                DeclarationName());
        if (!BaseTypeLoc) {
          Invalid = true;
          continue;
        }

        if (CXXBaseSpecifier *InstantiatedBase
              = CheckBaseSpecifier(Instantiation,
                                   Base.getSourceRange(),
                                   Base.isVirtual(),
                                   Base.getAccessSpecifierAsWritten(),
                                   BaseTypeLoc,
                                   SourceLocation()))
          InstantiatedBases.push_back(InstantiatedBase);
        else
          Invalid = true;
      }

      continue;
    }

    // The resulting base specifier will (still) be a pack expansion.
    EllipsisLoc = Base.getEllipsisLoc();
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  } else {
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  }

  if (!BaseTypeLoc) {
    Invalid = true;
    continue;
  }

  if (CXXBaseSpecifier *InstantiatedBase
        = CheckBaseSpecifier(Instantiation,
                             Base.getSourceRange(),
                             Base.isVirtual(),
                             Base.getAccessSpecifierAsWritten(),
                             BaseTypeLoc,
                             EllipsisLoc))
    InstantiatedBases.push_back(InstantiatedBase);
  else
    Invalid = true;
}

if (!Invalid && AttachBaseSpecifiers(Instantiation, InstantiatedBases))
  Invalid = true;

return Invalid;
2589}

2591// Defined via #include from SemaTemplateInstantiateDecl.cpp
2592namespace clang {
namespace sema {
  Attr *instantiateTemplateAttribute(const Attr *At, ASTContext &C, Sema &S,
                          const MultiLevelTemplateArgumentList &TemplateArgs);
  Attr *instantiateTemplateAttributeForDecl(
      const Attr *At, ASTContext &C, Sema &S,
      const MultiLevelTemplateArgumentList &TemplateArgs);
}
2600}

2602/// Instantiate the definition of a class from a given pattern.
2603///
2604/// \param PointOfInstantiation The point of instantiation within the
2605/// source code.
2606///
2607/// \param Instantiation is the declaration whose definition is being
2608/// instantiated. This will be either a class template specialization
2609/// or a member class of a class template specialization.
2610///
2611/// \param Pattern is the pattern from which the instantiation
2612/// occurs. This will be either the declaration of a class template or
2613/// the declaration of a member class of a class template.
2614///
2615/// \param TemplateArgs The template arguments to be substituted into
2616/// the pattern.
2617///
2618/// \param TSK the kind of implicit or explicit instantiation to perform.
2619///
2620/// \param Complain whether to complain if the class cannot be instantiated due
2621/// to the lack of a definition.
2622///
2623/// \returns true if an error occurred, false otherwise.
2624bool
2625Sema::InstantiateClass(SourceLocation PointOfInstantiation,
                     CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK,
                     bool Complain) {
CXXRecordDecl *PatternDef
8
←
'PatternDef' initialized to a null pointer value→
  = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
7
←
Assuming null pointer is passed into cast→
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation,
9
←
Assuming the condition is false→
10
←
Taking false branch→
                              Instantiation->getInstantiatedFromMemberClass(),
                                   Pattern, PatternDef, TSK, Complain))
  return true;

llvm::TimeTraceScope TimeScope("InstantiateClass", [&]() {
  std::string Name;
  llvm::raw_string_ostream OS(Name);
  Instantiation->getNameForDiagnostic(OS, getPrintingPolicy(),
                                      /*Qualified=*/true);
  return Name;
});

Pattern = PatternDef;
11
←
Null pointer value stored to 'Pattern'→

// Record the point of instantiation.
if (MemberSpecializationInfo *MSInfo
12
←
Assuming 'MSInfo' is null→
13
←
Taking false branch→
      = Instantiation->getMemberSpecializationInfo()) {
  MSInfo->setTemplateSpecializationKind(TSK);
  MSInfo->setPointOfInstantiation(PointOfInstantiation);
} else if (ClassTemplateSpecializationDecl *Spec14.1
'Spec' is null

14.1	'Spec' is null

←

Taking false branch

→

2653 = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {

←

Assuming 'Instantiation' is not a 'ClassTemplateSpecializationDecl'

→

2654 Spec->setTemplateSpecializationKind(TSK); 2655 Spec->setPointOfInstantiation(PointOfInstantiation); 2656 } 2657 2658 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);

←

Calling constructor for 'InstantiatingTemplate'

→

←

Returning from constructor for 'InstantiatingTemplate'

→

2659 if (Inst.isInvalid())

←

Calling 'InstantiatingTemplate::isInvalid'

→

←

Returning from 'InstantiatingTemplate::isInvalid'

→

←

Taking false branch

→

2660 return true; 2661 assert(!Inst.isAlreadyInstantiating() && "should have been caught by caller")((void)0); 2662 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2663 "instantiating class definition"); 2664 2665 // Enter the scope of this instantiation. We don't use 2666 // PushDeclContext because we don't have a scope. 2667 ContextRAII SavedContext(*this, Instantiation); 2668 EnterExpressionEvaluationContext EvalContext( 2669 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2670 2671 // If this is an instantiation of a local class, merge this local 2672 // instantiation scope with the enclosing scope. Otherwise, every 2673 // instantiation of a class has its own local instantiation scope. 2674 bool MergeWithParentScope = !Instantiation->isDefinedOutsideFunctionOrMethod(); 2675 LocalInstantiationScope Scope(*this, MergeWithParentScope); 2676 2677 // Some class state isn't processed immediately but delayed till class 2678 // instantiation completes. We may not be ready to handle any delayed state 2679 // already on the stack as it might correspond to a different class, so save 2680 // it now and put it back later. 2681 SavePendingParsedClassStateRAII SavedPendingParsedClassState(*this); 2682 2683 // Pull attributes from the pattern onto the instantiation. 2684 InstantiateAttrs(TemplateArgs, Pattern, Instantiation); 2685 2686 // Start the definition of this instantiation. 2687 Instantiation->startDefinition(); 2688 2689 // The instantiation is visible here, even if it was first declared in an 2690 // unimported module. 2691 Instantiation->setVisibleDespiteOwningModule(); 2692 2693 // FIXME: This loses the as-written tag kind for an explicit instantiation. 2694 Instantiation->setTagKind(Pattern->getTagKind());

←

Called C++ object pointer is null

2695 2696 // Do substitution on the base class specifiers. 2697 if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs)) 2698 Instantiation->setInvalidDecl(); 2699 2700 TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); 2701 SmallVector<Decl*, 4> Fields; 2702 // Delay instantiation of late parsed attributes. 2703 LateInstantiatedAttrVec LateAttrs; 2704 Instantiator.enableLateAttributeInstantiation(&LateAttrs); 2705 2706 bool MightHaveConstexprVirtualFunctions = false; 2707 for (auto *Member : Pattern->decls()) { 2708 // Don't instantiate members not belonging in this semantic context. 2709 // e.g. for: 2710 // @code 2711 // template <int i> class A { 2712 // class B *g; 2713 // }; 2714 // @endcode 2715 // 'class B' has the template as lexical context but semantically it is 2716 // introduced in namespace scope. 2717 if (Member->getDeclContext() != Pattern) 2718 continue; 2719 2720 // BlockDecls can appear in a default-member-initializer. They must be the 2721 // child of a BlockExpr, so we only know how to instantiate them from there. 2722 // Similarly, lambda closure types are recreated when instantiating the 2723 // corresponding LambdaExpr. 2724 if (isa<BlockDecl>(Member) || 2725 (isa<CXXRecordDecl>(Member) && cast<CXXRecordDecl>(Member)->isLambda())) 2726 continue; 2727 2728 if (Member->isInvalidDecl()) { 2729 Instantiation->setInvalidDecl(); 2730 continue; 2731 } 2732 2733 Decl *NewMember = Instantiator.Visit(Member); 2734 if (NewMember) { 2735 if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember)) { 2736 Fields.push_back(Field); 2737 } else if (EnumDecl *Enum = dyn_cast<EnumDecl>(NewMember)) { 2738 // C++11 [temp.inst]p1: The implicit instantiation of a class template 2739 // specialization causes the implicit instantiation of the definitions 2740 // of unscoped member enumerations. 2741 // Record a point of instantiation for this implicit instantiation. 2742 if (TSK == TSK_ImplicitInstantiation && !Enum->isScoped() && 2743 Enum->isCompleteDefinition()) { 2744 MemberSpecializationInfo *MSInfo =Enum->getMemberSpecializationInfo(); 2745 assert(MSInfo && "no spec info for member enum specialization")((void)0); 2746 MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation); 2747 MSInfo->setPointOfInstantiation(PointOfInstantiation); 2748 } 2749 } else if (StaticAssertDecl *SA = dyn_cast<StaticAssertDecl>(NewMember)) { 2750 if (SA->isFailed()) { 2751 // A static_assert failed. Bail out; instantiating this 2752 // class is probably not meaningful. 2753 Instantiation->setInvalidDecl(); 2754 break; 2755 } 2756 } else if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewMember)) { 2757 if (MD->isConstexpr() && !MD->getFriendObjectKind() && 2758 (MD->isVirtualAsWritten() || Instantiation->getNumBases())) 2759 MightHaveConstexprVirtualFunctions = true; 2760 } 2761 2762 if (NewMember->isInvalidDecl()) 2763 Instantiation->setInvalidDecl(); 2764 } else { 2765 // FIXME: Eventually, a NULL return will mean that one of the 2766 // instantiations was a semantic disaster, and we'll want to mark the 2767 // declaration invalid. 2768 // For now, we expect to skip some members that we can't yet handle. 2769 } 2770 } 2771 2772 // Finish checking fields. 2773 ActOnFields(nullptr, Instantiation->getLocation(), Instantiation, Fields, 2774 SourceLocation(), SourceLocation(), ParsedAttributesView()); 2775 CheckCompletedCXXClass(nullptr, Instantiation); 2776 2777 // Default arguments are parsed, if not instantiated. We can go instantiate 2778 // default arg exprs for default constructors if necessary now. Unless we're 2779 // parsing a class, in which case wait until that's finished. 2780 if (ParsingClassDepth == 0) 2781 ActOnFinishCXXNonNestedClass(); 2782 2783 // Instantiate late parsed attributes, and attach them to their decls. 2784 // See Sema::InstantiateAttrs 2785 for (LateInstantiatedAttrVec::iterator I = LateAttrs.begin(), 2786 E = LateAttrs.end(); I != E; ++I) { 2787 assert(CurrentInstantiationScope == Instantiator.getStartingScope())((void)0); 2788 CurrentInstantiationScope = I->Scope; 2789 2790 // Allow 'this' within late-parsed attributes. 2791 NamedDecl *ND = dyn_cast<NamedDecl>(I->NewDecl); 2792 CXXRecordDecl *ThisContext = 2793 dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext()); 2794 CXXThisScopeRAII ThisScope(*this, ThisContext, Qualifiers(), 2795 ND && ND->isCXXInstanceMember()); 2796 2797 Attr *NewAttr = 2798 instantiateTemplateAttribute(I->TmplAttr, Context, *this, TemplateArgs); 2799 if (NewAttr) 2800 I->NewDecl->addAttr(NewAttr); 2801 LocalInstantiationScope::deleteScopes(I->Scope, 2802 Instantiator.getStartingScope()); 2803 } 2804 Instantiator.disableLateAttributeInstantiation(); 2805 LateAttrs.clear(); 2806 2807 ActOnFinishDelayedMemberInitializers(Instantiation); 2808 2809 // FIXME: We should do something similar for explicit instantiations so they 2810 // end up in the right module. 2811 if (TSK == TSK_ImplicitInstantiation) { 2812 Instantiation->setLocation(Pattern->getLocation()); 2813 Instantiation->setLocStart(Pattern->getInnerLocStart()); 2814 Instantiation->setBraceRange(Pattern->getBraceRange()); 2815 } 2816 2817 if (!Instantiation->isInvalidDecl()) { 2818 // Perform any dependent diagnostics from the pattern. 2819 if (Pattern->isDependentContext()) 2820 PerformDependentDiagnostics(Pattern, TemplateArgs); 2821 2822 // Instantiate any out-of-line class template partial 2823 // specializations now. 2824 for (TemplateDeclInstantiator::delayed_partial_spec_iterator 2825 P = Instantiator.delayed_partial_spec_begin(), 2826 PEnd = Instantiator.delayed_partial_spec_end(); 2827 P != PEnd; ++P) { 2828 if (!Instantiator.InstantiateClassTemplatePartialSpecialization( 2829 P->first, P->second)) { 2830 Instantiation->setInvalidDecl(); 2831 break; 2832 } 2833 } 2834 2835 // Instantiate any out-of-line variable template partial 2836 // specializations now. 2837 for (TemplateDeclInstantiator::delayed_var_partial_spec_iterator 2838 P = Instantiator.delayed_var_partial_spec_begin(), 2839 PEnd = Instantiator.delayed_var_partial_spec_end(); 2840 P != PEnd; ++P) { 2841 if (!Instantiator.InstantiateVarTemplatePartialSpecialization( 2842 P->first, P->second)) { 2843 Instantiation->setInvalidDecl(); 2844 break; 2845 } 2846 } 2847 } 2848 2849 // Exit the scope of this instantiation. 2850 SavedContext.pop(); 2851 2852 if (!Instantiation->isInvalidDecl()) { 2853 // Always emit the vtable for an explicit instantiation definition 2854 // of a polymorphic class template specialization. Otherwise, eagerly 2855 // instantiate only constexpr virtual functions in preparation for their use 2856 // in constant evaluation. 2857 if (TSK == TSK_ExplicitInstantiationDefinition) 2858 MarkVTableUsed(PointOfInstantiation, Instantiation, true); 2859 else if (MightHaveConstexprVirtualFunctions) 2860 MarkVirtualMembersReferenced(PointOfInstantiation, Instantiation, 2861 /*ConstexprOnly*/ true); 2862 } 2863 2864 Consumer.HandleTagDeclDefinition(Instantiation); 2865 2866 return Instantiation->isInvalidDecl(); 2867} 2868 2869/// Instantiate the definition of an enum from a given pattern. 2870/// 2871/// \param PointOfInstantiation The point of instantiation within the 2872/// source code. 2873/// \param Instantiation is the declaration whose definition is being 2874/// instantiated. This will be a member enumeration of a class 2875/// temploid specialization, or a local enumeration within a 2876/// function temploid specialization. 2877/// \param Pattern The templated declaration from which the instantiation 2878/// occurs. 2879/// \param TemplateArgs The template arguments to be substituted into 2880/// the pattern. 2881/// \param TSK The kind of implicit or explicit instantiation to perform. 2882/// 2883/// \return \c true if an error occurred, \c false otherwise. 2884bool Sema::InstantiateEnum(SourceLocation PointOfInstantiation, 2885 EnumDecl *Instantiation, EnumDecl *Pattern, 2886 const MultiLevelTemplateArgumentList &TemplateArgs, 2887 TemplateSpecializationKind TSK) { 2888 EnumDecl *PatternDef = Pattern->getDefinition(); 2889 if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation, 2890 Instantiation->getInstantiatedFromMemberEnum(), 2891 Pattern, PatternDef, TSK,/*Complain*/true)) 2892 return true; 2893 Pattern = PatternDef; 2894 2895 // Record the point of instantiation. 2896 if (MemberSpecializationInfo *MSInfo 2897 = Instantiation->getMemberSpecializationInfo()) { 2898 MSInfo->setTemplateSpecializationKind(TSK); 2899 MSInfo->setPointOfInstantiation(PointOfInstantiation); 2900 } 2901 2902 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); 2903 if (Inst.isInvalid()) 2904 return true; 2905 if (Inst.isAlreadyInstantiating()) 2906 return false; 2907 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2908 "instantiating enum definition"); 2909 2910 // The instantiation is visible here, even if it was first declared in an 2911 // unimported module. 2912 Instantiation->setVisibleDespiteOwningModule(); 2913 2914 // Enter the scope of this instantiation. We don't use 2915 // PushDeclContext because we don't have a scope. 2916 ContextRAII SavedContext(*this, Instantiation); 2917 EnterExpressionEvaluationContext EvalContext( 2918 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2919 2920 LocalInstantiationScope Scope(*this, /*MergeWithParentScope*/true); 2921 2922 // Pull attributes from the pattern onto the instantiation. 2923 InstantiateAttrs(TemplateArgs, Pattern, Instantiation); 2924 2925 TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); 2926 Instantiator.InstantiateEnumDefinition(Instantiation, Pattern); 2927 2928 // Exit the scope of this instantiation. 2929 SavedContext.pop(); 2930 2931 return Instantiation->isInvalidDecl(); 2932} 2933 2934 2935/// Instantiate the definition of a field from the given pattern. 2936/// 2937/// \param PointOfInstantiation The point of instantiation within the 2938/// source code. 2939/// \param Instantiation is the declaration whose definition is being 2940/// instantiated. This will be a class of a class temploid 2941/// specialization, or a local enumeration within a function temploid 2942/// specialization. 2943/// \param Pattern The templated declaration from which the instantiation 2944/// occurs. 2945/// \param TemplateArgs The template arguments to be substituted into 2946/// the pattern. 2947/// 2948/// \return \c true if an error occurred, \c false otherwise. 2949bool Sema::InstantiateInClassInitializer( 2950 SourceLocation PointOfInstantiation, FieldDecl *Instantiation, 2951 FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs) { 2952 // If there is no initializer, we don't need to do anything. 2953 if (!Pattern->hasInClassInitializer()) 2954 return false; 2955 2956 assert(Instantiation->getInClassInitStyle() ==((void)0) 2957 Pattern->getInClassInitStyle() &&((void)0) 2958 "pattern and instantiation disagree about init style")((void)0); 2959 2960 // Error out if we haven't parsed the initializer of the pattern yet because 2961 // we are waiting for the closing brace of the outer class. 2962 Expr *OldInit = Pattern->getInClassInitializer(); 2963 if (!OldInit) { 2964 RecordDecl *PatternRD = Pattern->getParent(); 2965 RecordDecl *OutermostClass = PatternRD->getOuterLexicalRecordContext(); 2966 Diag(PointOfInstantiation, 2967 diag::err_default_member_initializer_not_yet_parsed) 2968 << OutermostClass << Pattern; 2969 Diag(Pattern->getEndLoc(), 2970 diag::note_default_member_initializer_not_yet_parsed); 2971 Instantiation->setInvalidDecl(); 2972 return true; 2973 } 2974 2975 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); 2976 if (Inst.isInvalid()) 2977 return true; 2978 if (Inst.isAlreadyInstantiating()) { 2979 // Error out if we hit an instantiation cycle for this initializer. 2980 Diag(PointOfInstantiation, diag::err_default_member_initializer_cycle) 2981 << Instantiation; 2982 return true; 2983 } 2984 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2985 "instantiating default member init"); 2986 2987 // Enter the scope of this instantiation. We don't use PushDeclContext because 2988 // we don't have a scope. 2989 ContextRAII SavedContext(*this, Instantiation->getParent()); 2990 EnterExpressionEvaluationContext EvalContext( 2991 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2992 2993 LocalInstantiationScope Scope(*this, true); 2994 2995 // Instantiate the initializer. 2996 ActOnStartCXXInClassMemberInitializer(); 2997 CXXThisScopeRAII ThisScope(*this, Instantiation->getParent(), Qualifiers()); 2998 2999 ExprResult NewInit = SubstInitializer(OldInit, TemplateArgs, 3000 /*CXXDirectInit=*/false); 3001 Expr *Init = NewInit.get(); 3002 assert((!Init || !isa<ParenListExpr>(Init)) && "call-style init in class")((void)0); 3003 ActOnFinishCXXInClassMemberInitializer( 3004 Instantiation, Init ? Init->getBeginLoc() : SourceLocation(), Init); 3005 3006 if (auto *L = getASTMutationListener()) 3007 L->DefaultMemberInitializerInstantiated(Instantiation); 3008 3009 // Return true if the in-class initializer is still missing. 3010 return !Instantiation->getInClassInitializer(); 3011} 3012 3013namespace { 3014 /// A partial specialization whose template arguments have matched 3015 /// a given template-id. 3016 struct PartialSpecMatchResult { 3017 ClassTemplatePartialSpecializationDecl *Partial; 3018 TemplateArgumentList *Args; 3019 }; 3020} 3021 3022bool Sema::usesPartialOrExplicitSpecialization( 3023 SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec) { 3024 if (ClassTemplateSpec->getTemplateSpecializationKind() == 3025 TSK_ExplicitSpecialization) 3026 return true; 3027 3028 SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs; 3029 ClassTemplateSpec->getSpecializedTemplate() 3030 ->getPartialSpecializations(PartialSpecs); 3031 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) { 3032 TemplateDeductionInfo Info(Loc); 3033 if (!DeduceTemplateArguments(PartialSpecs[I], 3034 ClassTemplateSpec->getTemplateArgs(), Info)) 3035 return true; 3036 } 3037 3038 return false; 3039} 3040 3041/// Get the instantiation pattern to use to instantiate the definition of a 3042/// given ClassTemplateSpecializationDecl (either the pattern of the primary 3043/// template or of a partial specialization). 3044static ActionResult<CXXRecordDecl *> 3045getPatternForClassTemplateSpecialization( 3046 Sema &S, SourceLocation PointOfInstantiation, 3047 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3048 TemplateSpecializationKind TSK) { 3049 Sema::InstantiatingTemplate Inst(S, PointOfInstantiation, ClassTemplateSpec); 3050 if (Inst.isInvalid()) 3051 return {/*Invalid=*/true}; 3052 if (Inst.isAlreadyInstantiating()) 3053 return {/*Invalid=*/false}; 3054 3055 llvm::PointerUnion<ClassTemplateDecl *, 3056 ClassTemplatePartialSpecializationDecl *> 3057 Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial(); 3058 if (!Specialized.is<ClassTemplatePartialSpecializationDecl *>()) { 3059 // Find best matching specialization. 3060 ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate(); 3061 3062 // C++ [temp.class.spec.match]p1: 3063 // When a class template is used in a context that requires an 3064 // instantiation of the class, it is necessary to determine 3065 // whether the instantiation is to be generated using the primary 3066 // template or one of the partial specializations. This is done by 3067 // matching the template arguments of the class template 3068 // specialization with the template argument lists of the partial 3069 // specializations. 3070 typedef PartialSpecMatchResult MatchResult; 3071 SmallVector<MatchResult, 4> Matched; 3072 SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs; 3073 Template->getPartialSpecializations(PartialSpecs); 3074 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation); 3075 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) { 3076 ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I]; 3077 TemplateDeductionInfo Info(FailedCandidates.getLocation()); 3078 if (Sema::TemplateDeductionResult Result = S.DeduceTemplateArguments( 3079 Partial, ClassTemplateSpec->getTemplateArgs(), Info)) { 3080 // Store the failed-deduction information for use in diagnostics, later. 3081 // TODO: Actually use the failed-deduction info? 3082 FailedCandidates.addCandidate().set( 3083 DeclAccessPair::make(Template, AS_public), Partial, 3084 MakeDeductionFailureInfo(S.Context, Result, Info)); 3085 (void)Result; 3086 } else { 3087 Matched.push_back(PartialSpecMatchResult()); 3088 Matched.back().Partial = Partial; 3089 Matched.back().Args = Info.take(); 3090 } 3091 } 3092 3093 // If we're dealing with a member template where the template parameters 3094 // have been instantiated, this provides the original template parameters 3095 // from which the member template's parameters were instantiated. 3096 3097 if (Matched.size() >= 1) { 3098 SmallVectorImpl<MatchResult>::iterator Best = Matched.begin(); 3099 if (Matched.size() == 1) { 3100 // -- If exactly one matching specialization is found, the 3101 // instantiation is generated from that specialization. 3102 // We don't need to do anything for this. 3103 } else { 3104 // -- If more than one matching specialization is found, the 3105 // partial order rules (14.5.4.2) are used to determine 3106 // whether one of the specializations is more specialized 3107 // than the others. If none of the specializations is more 3108 // specialized than all of the other matching 3109 // specializations, then the use of the class template is 3110 // ambiguous and the program is ill-formed. 3111 for (SmallVectorImpl<MatchResult>::iterator P = Best + 1, 3112 PEnd = Matched.end(); 3113 P != PEnd; ++P) { 3114 if (S.getMoreSpecializedPartialSpecialization( 3115 P->Partial, Best->Partial, PointOfInstantiation) == 3116 P->Partial) 3117 Best = P; 3118 } 3119 3120 // Determine if the best partial specialization is more specialized than 3121 // the others. 3122 bool Ambiguous = false; 3123 for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(), 3124 PEnd = Matched.end(); 3125 P != PEnd; ++P) { 3126 if (P != Best && S.getMoreSpecializedPartialSpecialization( 3127 P->Partial, Best->Partial, 3128 PointOfInstantiation) != Best->Partial) { 3129 Ambiguous = true; 3130 break; 3131 } 3132 } 3133 3134 if (Ambiguous) { 3135 // Partial ordering did not produce a clear winner. Complain. 3136 Inst.Clear(); 3137 ClassTemplateSpec->setInvalidDecl(); 3138 S.Diag(PointOfInstantiation, 3139 diag::err_partial_spec_ordering_ambiguous) 3140 << ClassTemplateSpec; 3141 3142 // Print the matching partial specializations. 3143 for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(), 3144 PEnd = Matched.end(); 3145 P != PEnd; ++P) 3146 S.Diag(P->Partial->getLocation(), diag::note_partial_spec_match) 3147 << S.getTemplateArgumentBindingsText( 3148 P->Partial->getTemplateParameters(), *P->Args); 3149 3150 return {/*Invalid=*/true}; 3151 } 3152 } 3153 3154 ClassTemplateSpec->setInstantiationOf(Best->Partial, Best->Args); 3155 } else { 3156 // -- If no matches are found, the instantiation is generated 3157 // from the primary template. 3158 } 3159 } 3160 3161 CXXRecordDecl *Pattern = nullptr; 3162 Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial(); 3163 if (auto *PartialSpec = 3164 Specialized.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) { 3165 // Instantiate using the best class template partial specialization. 3166 while (PartialSpec->getInstantiatedFromMember()) { 3167 // If we've found an explicit specialization of this class template, 3168 // stop here and use that as the pattern. 3169 if (PartialSpec->isMemberSpecialization()) 3170 break; 3171 3172 PartialSpec = PartialSpec->getInstantiatedFromMember(); 3173 } 3174 Pattern = PartialSpec; 3175 } else { 3176 ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate(); 3177 while (Template->getInstantiatedFromMemberTemplate()) { 3178 // If we've found an explicit specialization of this class template, 3179 // stop here and use that as the pattern. 3180 if (Template->isMemberSpecialization()) 3181 break; 3182 3183 Template = Template->getInstantiatedFromMemberTemplate(); 3184 } 3185 Pattern = Template->getTemplatedDecl(); 3186 } 3187 3188 return Pattern; 3189} 3190 3191bool Sema::InstantiateClassTemplateSpecialization( 3192 SourceLocation PointOfInstantiation, 3193 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3194 TemplateSpecializationKind TSK, bool Complain) { 3195 // Perform the actual instantiation on the canonical declaration. 3196 ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(

The object is a 'ClassTemplateSpecializationDecl'

→

3197 ClassTemplateSpec->getCanonicalDecl()); 3198 if (ClassTemplateSpec->isInvalidDecl())

←

Assuming the condition is false

→

←

Taking false branch

→

3199 return true; 3200 3201 ActionResult<CXXRecordDecl *> Pattern = 3202 getPatternForClassTemplateSpecialization(*this, PointOfInstantiation, 3203 ClassTemplateSpec, TSK); 3204 if (!Pattern.isUsable())

←

Assuming the condition is false

→

←

Taking false branch

→

3205 return Pattern.isInvalid(); 3206 3207 return InstantiateClass(

←

Calling 'Sema::InstantiateClass'

→

3208 PointOfInstantiation, ClassTemplateSpec, Pattern.get(), 3209 getTemplateInstantiationArgs(ClassTemplateSpec), TSK, Complain); 3210} 3211 3212/// Instantiates the definitions of all of the member 3213/// of the given class, which is an instantiation of a class template 3214/// or a member class of a template. 3215void 3216Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation, 3217 CXXRecordDecl *Instantiation, 3218 const MultiLevelTemplateArgumentList &TemplateArgs, 3219 TemplateSpecializationKind TSK) { 3220 // FIXME: We need to notify the ASTMutationListener that we did all of these 3221 // things, in case we have an explicit instantiation definition in a PCM, a 3222 // module, or preamble, and the declaration is in an imported AST. 3223 assert(((void)0) 3224 (TSK == TSK_ExplicitInstantiationDefinition ||((void)0) 3225 TSK == TSK_ExplicitInstantiationDeclaration ||((void)0) 3226 (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) &&((void)0) 3227 "Unexpected template specialization kind!")((void)0); 3228 for (auto *D : Instantiation->decls()) { 3229 bool SuppressNew = false; 3230 if (auto *Function = dyn_cast<FunctionDecl>(D)) { 3231 if (FunctionDecl *Pattern = 3232 Function->getInstantiatedFromMemberFunction()) { 3233 3234 if (Function->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3235 continue; 3236 3237 MemberSpecializationInfo *MSInfo = 3238 Function->getMemberSpecializationInfo(); 3239 assert(MSInfo && "No member specialization information?")((void)0); 3240 if (MSInfo->getTemplateSpecializationKind() 3241 == TSK_ExplicitSpecialization) 3242 continue; 3243 3244 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3245 Function, 3246 MSInfo->getTemplateSpecializationKind(), 3247 MSInfo->getPointOfInstantiation(), 3248 SuppressNew) || 3249 SuppressNew) 3250 continue; 3251 3252 // C++11 [temp.explicit]p8: 3253 // An explicit instantiation definition that names a class template 3254 // specialization explicitly instantiates the class template 3255 // specialization and is only an explicit instantiation definition 3256 // of members whose definition is visible at the point of 3257 // instantiation. 3258 if (TSK == TSK_ExplicitInstantiationDefinition && !Pattern->isDefined()) 3259 continue; 3260 3261 Function->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3262 3263 if (Function->isDefined()) { 3264 // Let the ASTConsumer know that this function has been explicitly 3265 // instantiated now, and its linkage might have changed. 3266 Consumer.HandleTopLevelDecl(DeclGroupRef(Function)); 3267 } else if (TSK == TSK_ExplicitInstantiationDefinition) { 3268 InstantiateFunctionDefinition(PointOfInstantiation, Function); 3269 } else if (TSK == TSK_ImplicitInstantiation) { 3270 PendingLocalImplicitInstantiations.push_back( 3271 std::make_pair(Function, PointOfInstantiation)); 3272 } 3273 } 3274 } else if (auto *Var = dyn_cast<VarDecl>(D)) { 3275 if (isa<VarTemplateSpecializationDecl>(Var)) 3276 continue; 3277 3278 if (Var->isStaticDataMember()) { 3279 if (Var->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3280 continue; 3281 3282 MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo(); 3283 assert(MSInfo && "No member specialization information?")((void)0); 3284 if (MSInfo->getTemplateSpecializationKind() 3285 == TSK_ExplicitSpecialization) 3286 continue; 3287 3288 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3289 Var, 3290 MSInfo->getTemplateSpecializationKind(), 3291 MSInfo->getPointOfInstantiation(), 3292 SuppressNew) || 3293 SuppressNew) 3294 continue; 3295 3296 if (TSK == TSK_ExplicitInstantiationDefinition) { 3297 // C++0x [temp.explicit]p8: 3298 // An explicit instantiation definition that names a class template 3299 // specialization explicitly instantiates the class template 3300 // specialization and is only an explicit instantiation definition 3301 // of members whose definition is visible at the point of 3302 // instantiation. 3303 if (!Var->getInstantiatedFromStaticDataMember()->getDefinition()) 3304 continue; 3305 3306 Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3307 InstantiateVariableDefinition(PointOfInstantiation, Var); 3308 } else { 3309 Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3310 } 3311 } 3312 } else if (auto *Record = dyn_cast<CXXRecordDecl>(D)) { 3313 if (Record->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3314 continue; 3315 3316 // Always skip the injected-class-name, along with any 3317 // redeclarations of nested classes, since both would cause us 3318 // to try to instantiate the members of a class twice. 3319 // Skip closure types; they'll get instantiated when we instantiate 3320 // the corresponding lambda-expression. 3321 if (Record->isInjectedClassName() || Record->getPreviousDecl() || 3322 Record->isLambda()) 3323 continue; 3324 3325 MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo(); 3326 assert(MSInfo && "No member specialization information?")((void)0); 3327 3328 if (MSInfo->getTemplateSpecializationKind() 3329 == TSK_ExplicitSpecialization) 3330 continue; 3331 3332 if (Context.getTargetInfo().getTriple().isOSWindows() && 3333 TSK == TSK_ExplicitInstantiationDeclaration) { 3334 // On Windows, explicit instantiation decl of the outer class doesn't 3335 // affect the inner class. Typically extern template declarations are 3336 // used in combination with dll import/export annotations, but those 3337 // are not propagated from the outer class templates to inner classes. 3338 // Therefore, do not instantiate inner classes on this platform, so 3339 // that users don't end up with undefined symbols during linking. 3340 continue; 3341 } 3342 3343 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3344 Record, 3345 MSInfo->getTemplateSpecializationKind(), 3346 MSInfo->getPointOfInstantiation(), 3347 SuppressNew) || 3348 SuppressNew) 3349 continue; 3350 3351 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass(); 3352 assert(Pattern && "Missing instantiated-from-template information")((void)0); 3353 3354 if (!Record->getDefinition()) { 3355 if (!Pattern->getDefinition()) { 3356 // C++0x [temp.explicit]p8: 3357 // An explicit instantiation definition that names a class template 3358 // specialization explicitly instantiates the class template 3359 // specialization and is only an explicit instantiation definition 3360 // of members whose definition is visible at the point of 3361 // instantiation. 3362 if (TSK == TSK_ExplicitInstantiationDeclaration) { 3363 MSInfo->setTemplateSpecializationKind(TSK); 3364 MSInfo->setPointOfInstantiation(PointOfInstantiation); 3365 } 3366 3367 continue; 3368 } 3369 3370 InstantiateClass(PointOfInstantiation, Record, Pattern, 3371 TemplateArgs, 3372 TSK); 3373 } else { 3374 if (TSK == TSK_ExplicitInstantiationDefinition && 3375 Record->getTemplateSpecializationKind() == 3376 TSK_ExplicitInstantiationDeclaration) { 3377 Record->setTemplateSpecializationKind(TSK); 3378 MarkVTableUsed(PointOfInstantiation, Record, true); 3379 } 3380 } 3381 3382 Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition()); 3383 if (Pattern) 3384 InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs, 3385 TSK); 3386 } else if (auto *Enum = dyn_cast<EnumDecl>(D)) { 3387 MemberSpecializationInfo *MSInfo = Enum->getMemberSpecializationInfo(); 3388 assert(MSInfo && "No member specialization information?")((void)0); 3389 3390 if (MSInfo->getTemplateSpecializationKind() 3391 == TSK_ExplicitSpecialization) 3392 continue; 3393 3394 if (CheckSpecializationInstantiationRedecl( 3395 PointOfInstantiation, TSK, Enum, 3396 MSInfo->getTemplateSpecializationKind(), 3397 MSInfo->getPointOfInstantiation(), SuppressNew) || 3398 SuppressNew) 3399 continue; 3400 3401 if (Enum->getDefinition()) 3402 continue; 3403 3404 EnumDecl *Pattern = Enum->getTemplateInstantiationPattern(); 3405 assert(Pattern && "Missing instantiated-from-template information")((void)0); 3406 3407 if (TSK == TSK_ExplicitInstantiationDefinition) { 3408 if (!Pattern->getDefinition()) 3409 continue; 3410 3411 InstantiateEnum(PointOfInstantiation, Enum, Pattern, TemplateArgs, TSK); 3412 } else { 3413 MSInfo->setTemplateSpecializationKind(TSK); 3414 MSInfo->setPointOfInstantiation(PointOfInstantiation); 3415 } 3416 } else if (auto *Field = dyn_cast<FieldDecl>(D)) { 3417 // No need to instantiate in-class initializers during explicit 3418 // instantiation. 3419 if (Field->hasInClassInitializer() && TSK == TSK_ImplicitInstantiation) { 3420 CXXRecordDecl *ClassPattern = 3421 Instantiation->getTemplateInstantiationPattern(); 3422 DeclContext::lookup_result Lookup = 3423 ClassPattern->lookup(Field->getDeclName()); 3424 FieldDecl *Pattern = Lookup.find_first<FieldDecl>(); 3425 assert(Pattern)((void)0); 3426 InstantiateInClassInitializer(PointOfInstantiation, Field, Pattern, 3427 TemplateArgs); 3428 } 3429 } 3430 } 3431} 3432 3433/// Instantiate the definitions of all of the members of the 3434/// given class template specialization, which was named as part of an 3435/// explicit instantiation. 3436void 3437Sema::InstantiateClassTemplateSpecializationMembers( 3438 SourceLocation PointOfInstantiation, 3439 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3440 TemplateSpecializationKind TSK) { 3441 // C++0x [temp.explicit]p7: 3442 // An explicit instantiation that names a class template 3443 // specialization is an explicit instantion of the same kind 3444 // (declaration or definition) of each of its members (not 3445 // including members inherited from base classes) that has not 3446 // been previously explicitly specialized in the translation unit 3447 // containing the explicit instantiation, except as described 3448 // below. 3449 InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec, 3450 getTemplateInstantiationArgs(ClassTemplateSpec), 3451 TSK); 3452} 3453 3454StmtResult 3455Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) { 3456 if (!S) 3457 return S; 3458 3459 TemplateInstantiator Instantiator(*this, TemplateArgs, 3460 SourceLocation(), 3461 DeclarationName()); 3462 return Instantiator.TransformStmt(S); 3463} 3464 3465bool Sema::SubstTemplateArguments( 3466 ArrayRef<TemplateArgumentLoc> Args, 3467 const MultiLevelTemplateArgumentList &TemplateArgs, 3468 TemplateArgumentListInfo &Out) { 3469 TemplateInstantiator Instantiator(*this, TemplateArgs, 3470 SourceLocation(), 3471 DeclarationName()); 3472 return Instantiator.TransformTemplateArguments(Args.begin(), Args.end(), 3473 Out); 3474} 3475 3476ExprResult 3477Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) { 3478 if (!E) 3479 return E; 3480 3481 TemplateInstantiator Instantiator(*this, TemplateArgs, 3482 SourceLocation(), 3483 DeclarationName()); 3484 return Instantiator.TransformExpr(E); 3485} 3486 3487ExprResult Sema::SubstInitializer(Expr *Init, 3488 const MultiLevelTemplateArgumentList &TemplateArgs, 3489 bool CXXDirectInit) { 3490 TemplateInstantiator Instantiator(*this, TemplateArgs, 3491 SourceLocation(), 3492 DeclarationName()); 3493 return Instantiator.TransformInitializer(Init, CXXDirectInit); 3494} 3495 3496bool Sema::SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall, 3497 const MultiLevelTemplateArgumentList &TemplateArgs, 3498 SmallVectorImpl<Expr *> &Outputs) { 3499 if (Exprs.empty()) 3500 return false; 3501 3502 TemplateInstantiator Instantiator(*this, TemplateArgs, 3503 SourceLocation(), 3504 DeclarationName()); 3505 return Instantiator.TransformExprs(Exprs.data(), Exprs.size(), 3506 IsCall, Outputs); 3507} 3508 3509NestedNameSpecifierLoc 3510Sema::SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS, 3511 const MultiLevelTemplateArgumentList &TemplateArgs) { 3512 if (!NNS) 3513 return NestedNameSpecifierLoc(); 3514 3515 TemplateInstantiator Instantiator(*this, TemplateArgs, NNS.getBeginLoc(), 3516 DeclarationName()); 3517 return Instantiator.TransformNestedNameSpecifierLoc(NNS); 3518} 3519 3520/// Do template substitution on declaration name info. 3521DeclarationNameInfo 3522Sema::SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo, 3523 const MultiLevelTemplateArgumentList &TemplateArgs) { 3524 TemplateInstantiator Instantiator(*this, TemplateArgs, NameInfo.getLoc(), 3525 NameInfo.getName()); 3526 return Instantiator.TransformDeclarationNameInfo(NameInfo); 3527} 3528 3529TemplateName 3530Sema::SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, 3531 TemplateName Name, SourceLocation Loc, 3532 const MultiLevelTemplateArgumentList &TemplateArgs) { 3533 TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, 3534 DeclarationName()); 3535 CXXScopeSpec SS; 3536 SS.Adopt(QualifierLoc); 3537 return Instantiator.TransformTemplateName(SS, Name, Loc); 3538} 3539 3540bool Sema::Subst(const TemplateArgumentLoc *Args, unsigned NumArgs, 3541 TemplateArgumentListInfo &Result, 3542 const MultiLevelTemplateArgumentList &TemplateArgs) { 3543 TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), 3544 DeclarationName()); 3545 3546 return Instantiator.TransformTemplateArguments(Args, NumArgs, Result); 3547} 3548 3549static const Decl *getCanonicalParmVarDecl(const Decl *D) { 3550 // When storing ParmVarDecls in the local instantiation scope, we always 3551 // want to use the ParmVarDecl from the canonical function declaration, 3552 // since the map is then valid for any redeclaration or definition of that 3553 // function. 3554 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(D)) { 3555 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 3556 unsigned i = PV->getFunctionScopeIndex(); 3557 // This parameter might be from a freestanding function type within the 3558 // function and isn't necessarily referring to one of FD's parameters. 3559 if (i < FD->getNumParams() && FD->getParamDecl(i) == PV) 3560 return FD->getCanonicalDecl()->getParamDecl(i); 3561 } 3562 } 3563 return D; 3564} 3565 3566 3567llvm::PointerUnion<Decl *, LocalInstantiationScope::DeclArgumentPack *> * 3568LocalInstantiationScope::findInstantiationOf(const Decl *D) { 3569 D = getCanonicalParmVarDecl(D); 3570 for (LocalInstantiationScope *Current = this; Current; 3571 Current = Current->Outer) { 3572 3573 // Check if we found something within this scope. 3574 const Decl *CheckD = D; 3575 do { 3576 LocalDeclsMap::iterator Found = Current->LocalDecls.find(CheckD); 3577 if (Found != Current->LocalDecls.end()) 3578 return &Found->second; 3579 3580 // If this is a tag declaration, it's possible that we need to look for 3581 // a previous declaration. 3582 if (const TagDecl *Tag = dyn_cast<TagDecl>(CheckD)) 3583 CheckD = Tag->getPreviousDecl(); 3584 else 3585 CheckD = nullptr; 3586 } while (CheckD); 3587 3588 // If we aren't combined with our outer scope, we're done. 3589 if (!Current->CombineWithOuterScope) 3590 break; 3591 } 3592 3593 // If we're performing a partial substitution during template argument 3594 // deduction, we may not have values for template parameters yet. 3595 if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) || 3596 isa<TemplateTemplateParmDecl>(D)) 3597 return nullptr; 3598 3599 // Local types referenced prior to definition may require instantiation. 3600 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) 3601 if (RD->isLocalClass()) 3602 return nullptr; 3603 3604 // Enumeration types referenced prior to definition may appear as a result of 3605 // error recovery. 3606 if (isa<EnumDecl>(D)) 3607 return nullptr; 3608 3609 // Materialized typedefs/type alias for implicit deduction guides may require 3610 // instantiation. 3611 if (isa<TypedefNameDecl>(D) && 3612 isa<CXXDeductionGuideDecl>(D->getDeclContext())) 3613 return nullptr; 3614 3615 // If we didn't find the decl, then we either have a sema bug, or we have a 3616 // forward reference to a label declaration. Return null to indicate that 3617 // we have an uninstantiated label. 3618 assert(isa<LabelDecl>(D) && "declaration not instantiated in this scope")((void)0); 3619 return nullptr; 3620} 3621 3622void LocalInstantiationScope::InstantiatedLocal(const Decl *D, Decl *Inst) { 3623 D = getCanonicalParmVarDecl(D); 3624 llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D]; 3625 if (Stored.isNull()) { 3626#ifndef NDEBUG1 3627 // It should not be present in any surrounding scope either. 3628 LocalInstantiationScope *Current = this; 3629 while (Current->CombineWithOuterScope && Current->Outer) { 3630 Current = Current->Outer; 3631 assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&((void)0) 3632 "Instantiated local in inner and outer scopes")((void)0); 3633 } 3634#endif 3635 Stored = Inst; 3636 } else if (DeclArgumentPack *Pack = Stored.dyn_cast<DeclArgumentPack *>()) { 3637 Pack->push_back(cast<VarDecl>(Inst)); 3638 } else { 3639 assert(Stored.get<Decl *>() == Inst && "Already instantiated this local")((void)0); 3640 } 3641} 3642 3643void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D, 3644 VarDecl *Inst) { 3645 D = getCanonicalParmVarDecl(D); 3646 DeclArgumentPack *Pack = LocalDecls[D].get<DeclArgumentPack *>(); 3647 Pack->push_back(Inst); 3648} 3649 3650void LocalInstantiationScope::MakeInstantiatedLocalArgPack(const Decl *D) { 3651#ifndef NDEBUG1 3652 // This should be the first time we've been told about this decl. 3653 for (LocalInstantiationScope *Current = this; 3654 Current && Current->CombineWithOuterScope; Current = Current->Outer) 3655 assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&((void)0) 3656 "Creating local pack after instantiation of local")((void)0); 3657#endif 3658 3659 D = getCanonicalParmVarDecl(D); 3660 llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D]; 3661 DeclArgumentPack *Pack = new DeclArgumentPack; 3662 Stored = Pack; 3663 ArgumentPacks.push_back(Pack); 3664} 3665 3666bool LocalInstantiationScope::isLocalPackExpansion(const Decl *D) { 3667 for (DeclArgumentPack *Pack : ArgumentPacks) 3668 if (std::find(Pack->begin(), Pack->end(), D) != Pack->end()) 3669 return true; 3670 return false; 3671} 3672 3673void LocalInstantiationScope::SetPartiallySubstitutedPack(NamedDecl *Pack, 3674 const TemplateArgument *ExplicitArgs, 3675 unsigned NumExplicitArgs) { 3676 assert((!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) &&((void)0) 3677 "Already have a partially-substituted pack")((void)0); 3678 assert((!PartiallySubstitutedPack((void)0) 3679 || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) &&((void)0) 3680 "Wrong number of arguments in partially-substituted pack")((void)0); 3681 PartiallySubstitutedPack = Pack; 3682 ArgsInPartiallySubstitutedPack = ExplicitArgs; 3683 NumArgsInPartiallySubstitutedPack = NumExplicitArgs; 3684} 3685 3686NamedDecl *LocalInstantiationScope::getPartiallySubstitutedPack( 3687 const TemplateArgument **ExplicitArgs, 3688 unsigned *NumExplicitArgs) const { 3689 if (ExplicitArgs) 3690 *ExplicitArgs = nullptr; 3691 if (NumExplicitArgs) 3692 *NumExplicitArgs = 0; 3693 3694 for (const LocalInstantiationScope *Current = this; Current; 3695 Current = Current->Outer) { 3696 if (Current->PartiallySubstitutedPack) { 3697 if (ExplicitArgs) 3698 *ExplicitArgs = Current->ArgsInPartiallySubstitutedPack; 3699 if (NumExplicitArgs) 3700 *NumExplicitArgs = Current->NumArgsInPartiallySubstitutedPack; 3701 3702 return Current->PartiallySubstitutedPack; 3703 } 3704 3705 if (!Current->CombineWithOuterScope) 3706 break; 3707 } 3708 3709 return nullptr; 3710}

←

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

1//===--- Sema.h - Semantic Analysis & AST Building --------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the Sema class, which performs semantic analysis and
10// builds ASTs.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_CLANG_SEMA_SEMA_H
15#define LLVM_CLANG_SEMA_SEMA_H

17#include "clang/AST/ASTConcept.h"
18#include "clang/AST/ASTFwd.h"
19#include "clang/AST/Attr.h"
20#include "clang/AST/Availability.h"
21#include "clang/AST/ComparisonCategories.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/ExprConcepts.h"
27#include "clang/AST/ExprObjC.h"
28#include "clang/AST/ExprOpenMP.h"
29#include "clang/AST/ExternalASTSource.h"
30#include "clang/AST/LocInfoType.h"
31#include "clang/AST/MangleNumberingContext.h"
32#include "clang/AST/NSAPI.h"
33#include "clang/AST/PrettyPrinter.h"
34#include "clang/AST/StmtCXX.h"
35#include "clang/AST/StmtOpenMP.h"
36#include "clang/AST/TypeLoc.h"
37#include "clang/AST/TypeOrdering.h"
38#include "clang/Basic/BitmaskEnum.h"
39#include "clang/Basic/Builtins.h"
40#include "clang/Basic/DarwinSDKInfo.h"
41#include "clang/Basic/ExpressionTraits.h"
42#include "clang/Basic/Module.h"
43#include "clang/Basic/OpenCLOptions.h"
44#include "clang/Basic/OpenMPKinds.h"
45#include "clang/Basic/PragmaKinds.h"
46#include "clang/Basic/Specifiers.h"
47#include "clang/Basic/TemplateKinds.h"
48#include "clang/Basic/TypeTraits.h"
49#include "clang/Sema/AnalysisBasedWarnings.h"
50#include "clang/Sema/CleanupInfo.h"
51#include "clang/Sema/DeclSpec.h"
52#include "clang/Sema/ExternalSemaSource.h"
53#include "clang/Sema/IdentifierResolver.h"
54#include "clang/Sema/ObjCMethodList.h"
55#include "clang/Sema/Ownership.h"
56#include "clang/Sema/Scope.h"
57#include "clang/Sema/SemaConcept.h"
58#include "clang/Sema/TypoCorrection.h"
59#include "clang/Sema/Weak.h"
60#include "llvm/ADT/ArrayRef.h"
61#include "llvm/ADT/Optional.h"
62#include "llvm/ADT/SetVector.h"
63#include "llvm/ADT/SmallBitVector.h"
64#include "llvm/ADT/SmallPtrSet.h"
65#include "llvm/ADT/SmallSet.h"
66#include "llvm/ADT/SmallVector.h"
67#include "llvm/ADT/TinyPtrVector.h"
68#include "llvm/Frontend/OpenMP/OMPConstants.h"
69#include <deque>
70#include <memory>
71#include <string>
72#include <tuple>
73#include <vector>

75namespace llvm {
class APSInt;
template <typename ValueT> struct DenseMapInfo;
template <typename ValueT, typename ValueInfoT> class DenseSet;
class SmallBitVector;
struct InlineAsmIdentifierInfo;
81}

83namespace clang {
class ADLResult;
class ASTConsumer;
class ASTContext;
class ASTMutationListener;
class ASTReader;
class ASTWriter;
class ArrayType;
class ParsedAttr;
class BindingDecl;
class BlockDecl;
class CapturedDecl;
class CXXBasePath;
class CXXBasePaths;
class CXXBindTemporaryExpr;
typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
class CXXConstructorDecl;
class CXXConversionDecl;
class CXXDeleteExpr;
class CXXDestructorDecl;
class CXXFieldCollector;
class CXXMemberCallExpr;
class CXXMethodDecl;
class CXXScopeSpec;
class CXXTemporary;
class CXXTryStmt;
class CallExpr;
class ClassTemplateDecl;
class ClassTemplatePartialSpecializationDecl;
class ClassTemplateSpecializationDecl;
class VarTemplatePartialSpecializationDecl;
class CodeCompleteConsumer;
class CodeCompletionAllocator;
class CodeCompletionTUInfo;
class CodeCompletionResult;
class CoroutineBodyStmt;
class Decl;
class DeclAccessPair;
class DeclContext;
class DeclRefExpr;
class DeclaratorDecl;
class DeducedTemplateArgument;
class DependentDiagnostic;
class DesignatedInitExpr;
class Designation;
class EnableIfAttr;
class EnumConstantDecl;
class Expr;
class ExtVectorType;
class FormatAttr;
class FriendDecl;
class FunctionDecl;
class FunctionProtoType;
class FunctionTemplateDecl;
class ImplicitConversionSequence;
typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
class InitListExpr;
class InitializationKind;
class InitializationSequence;
class InitializedEntity;
class IntegerLiteral;
class LabelStmt;
class LambdaExpr;
class LangOptions;
class LocalInstantiationScope;
class LookupResult;
class MacroInfo;
typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation>> ModuleIdPath;
class ModuleLoader;
class MultiLevelTemplateArgumentList;
class NamedDecl;
class ObjCCategoryDecl;
class ObjCCategoryImplDecl;
class ObjCCompatibleAliasDecl;
class ObjCContainerDecl;
class ObjCImplDecl;
class ObjCImplementationDecl;
class ObjCInterfaceDecl;
class ObjCIvarDecl;
template <class T> class ObjCList;
class ObjCMessageExpr;
class ObjCMethodDecl;
class ObjCPropertyDecl;
class ObjCProtocolDecl;
class OMPThreadPrivateDecl;
class OMPRequiresDecl;
class OMPDeclareReductionDecl;
class OMPDeclareSimdDecl;
class OMPClause;
struct OMPVarListLocTy;
struct OverloadCandidate;
enum class OverloadCandidateParamOrder : char;
enum OverloadCandidateRewriteKind : unsigned;
class OverloadCandidateSet;
class OverloadExpr;
class ParenListExpr;
class ParmVarDecl;
class Preprocessor;
class PseudoDestructorTypeStorage;
class PseudoObjectExpr;
class QualType;
class StandardConversionSequence;
class Stmt;
class StringLiteral;
class SwitchStmt;
class TemplateArgument;
class TemplateArgumentList;
class TemplateArgumentLoc;
class TemplateDecl;
class TemplateInstantiationCallback;
class TemplateParameterList;
class TemplatePartialOrderingContext;
class TemplateTemplateParmDecl;
class Token;
class TypeAliasDecl;
class TypedefDecl;
class TypedefNameDecl;
class TypeLoc;
class TypoCorrectionConsumer;
class UnqualifiedId;
class UnresolvedLookupExpr;
class UnresolvedMemberExpr;
class UnresolvedSetImpl;
class UnresolvedSetIterator;
class UsingDecl;
class UsingShadowDecl;
class ValueDecl;
class VarDecl;
class VarTemplateSpecializationDecl;
class VisibilityAttr;
class VisibleDeclConsumer;
class IndirectFieldDecl;
struct DeductionFailureInfo;
class TemplateSpecCandidateSet;

218namespace sema {
class AccessedEntity;
class BlockScopeInfo;
class Capture;
class CapturedRegionScopeInfo;
class CapturingScopeInfo;
class CompoundScopeInfo;
class DelayedDiagnostic;
class DelayedDiagnosticPool;
class FunctionScopeInfo;
class LambdaScopeInfo;
class PossiblyUnreachableDiag;
class SemaPPCallbacks;
class TemplateDeductionInfo;
232}

234namespace threadSafety {
class BeforeSet;
void threadSafetyCleanup(BeforeSet* Cache);
237}

239// FIXME: No way to easily map from TemplateTypeParmTypes to
240// TemplateTypeParmDecls, so we have this horrible PointerUnion.
241typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType*, NamedDecl*>,
                SourceLocation> UnexpandedParameterPack;

244/// Describes whether we've seen any nullability information for the given
245/// file.
246struct FileNullability {
/// The first pointer declarator (of any pointer kind) in the file that does
/// not have a corresponding nullability annotation.
SourceLocation PointerLoc;

/// The end location for the first pointer declarator in the file. Used for
/// placing fix-its.
SourceLocation PointerEndLoc;

/// Which kind of pointer declarator we saw.
uint8_t PointerKind;

/// Whether we saw any type nullability annotations in the given file.
bool SawTypeNullability = false;
260};

262/// A mapping from file IDs to a record of whether we've seen nullability
263/// information in that file.
264class FileNullabilityMap {
/// A mapping from file IDs to the nullability information for each file ID.
llvm::DenseMap<FileID, FileNullability> Map;

/// A single-element cache based on the file ID.
struct {
  FileID File;
  FileNullability Nullability;
} Cache;

274public:
FileNullability &operator[](FileID file) {
  // Check the single-element cache.
  if (file == Cache.File)
    return Cache.Nullability;

  // It's not in the single-element cache; flush the cache if we have one.
  if (!Cache.File.isInvalid()) {
    Map[Cache.File] = Cache.Nullability;
  }

  // Pull this entry into the cache.
  Cache.File = file;
  Cache.Nullability = Map[file];
  return Cache.Nullability;
}
290};

292/// Tracks expected type during expression parsing, for use in code completion.
293/// The type is tied to a particular token, all functions that update or consume
294/// the type take a start location of the token they are looking at as a
295/// parameter. This avoids updating the type on hot paths in the parser.
296class PreferredTypeBuilder {
297public:
PreferredTypeBuilder(bool Enabled) : Enabled(Enabled) {}

void enterCondition(Sema &S, SourceLocation Tok);
void enterReturn(Sema &S, SourceLocation Tok);
void enterVariableInit(SourceLocation Tok, Decl *D);
/// Handles e.g. BaseType{ .D = Tok...
void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
                                const Designation &D);
/// Computing a type for the function argument may require running
/// overloading, so we postpone its computation until it is actually needed.
///
/// Clients should be very careful when using this funciton, as it stores a
/// function_ref, clients should make sure all calls to get() with the same
/// location happen while function_ref is alive.
///
/// The callback should also emit signature help as a side-effect, but only
/// if the completion point has been reached.
void enterFunctionArgument(SourceLocation Tok,
                           llvm::function_ref<QualType()> ComputeType);

void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
                SourceLocation OpLoc);
void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
/// Handles all type casts, including C-style cast, C++ casts, etc.
void enterTypeCast(SourceLocation Tok, QualType CastType);

/// Get the expected type associated with this location, if any.
///
/// If the location is a function argument, determining the expected type
/// involves considering all function overloads and the arguments so far.
/// In this case, signature help for these function overloads will be reported
/// as a side-effect (only if the completion point has been reached).
QualType get(SourceLocation Tok) const {
  if (!Enabled || Tok != ExpectedLoc)
    return QualType();
  if (!Type.isNull())
    return Type;
  if (ComputeType)
    return ComputeType();
  return QualType();
}

343private:
bool Enabled;
/// Start position of a token for which we store expected type.
SourceLocation ExpectedLoc;
/// Expected type for a token starting at ExpectedLoc.
QualType Type;
/// A function to compute expected type at ExpectedLoc. It is only considered
/// if Type is null.
llvm::function_ref<QualType()> ComputeType;
352};

354/// Sema - This implements semantic analysis and AST building for C.
355class Sema final {
Sema(const Sema &) = delete;
void operator=(const Sema &) = delete;

///Source of additional semantic information.
ExternalSemaSource *ExternalSource;

///Whether Sema has generated a multiplexer and has to delete it.
bool isMultiplexExternalSource;

static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);

bool isVisibleSlow(const NamedDecl *D);

/// Determine whether two declarations should be linked together, given that
/// the old declaration might not be visible and the new declaration might
/// not have external linkage.
bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
                                  const NamedDecl *New) {
  if (isVisible(Old))
   return true;
  // See comment in below overload for why it's safe to compute the linkage
  // of the new declaration here.
  if (New->isExternallyDeclarable()) {
    assert(Old->isExternallyDeclarable() &&((void)0)
           "should not have found a non-externally-declarable previous decl")((void)0);
    return true;
  }
  return false;
}
bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);

void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
                                    QualType ResultTy,
                                    ArrayRef<QualType> Args);

391public:
/// The maximum alignment, same as in llvm::Value. We duplicate them here
/// because that allows us not to duplicate the constants in clang code,
/// which we must to since we can't directly use the llvm constants.
/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
///
/// This is the greatest alignment value supported by load, store, and alloca
/// instructions, and global values.
static const unsigned MaxAlignmentExponent = 29;
static const unsigned MaximumAlignment = 1u << MaxAlignmentExponent;

typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
typedef OpaquePtr<TemplateName> TemplateTy;
typedef OpaquePtr<QualType> TypeTy;

OpenCLOptions OpenCLFeatures;
FPOptions CurFPFeatures;

const LangOptions &LangOpts;
Preprocessor &PP;
ASTContext &Context;
ASTConsumer &Consumer;
DiagnosticsEngine &Diags;
SourceManager &SourceMgr;

/// Flag indicating whether or not to collect detailed statistics.
bool CollectStats;

/// Code-completion consumer.
CodeCompleteConsumer *CodeCompleter;

/// CurContext - This is the current declaration context of parsing.
DeclContext *CurContext;

/// Generally null except when we temporarily switch decl contexts,
/// like in \see ActOnObjCTemporaryExitContainerContext.
DeclContext *OriginalLexicalContext;

/// VAListTagName - The declaration name corresponding to __va_list_tag.
/// This is used as part of a hack to omit that class from ADL results.
DeclarationName VAListTagName;

bool MSStructPragmaOn; // True when \#pragma ms_struct on

/// Controls member pointer representation format under the MS ABI.
LangOptions::PragmaMSPointersToMembersKind
    MSPointerToMemberRepresentationMethod;

/// Stack of active SEH __finally scopes.  Can be empty.
SmallVector<Scope*, 2> CurrentSEHFinally;

/// Source location for newly created implicit MSInheritanceAttrs
SourceLocation ImplicitMSInheritanceAttrLoc;

/// Holds TypoExprs that are created from `createDelayedTypo`. This is used by
/// `TransformTypos` in order to keep track of any TypoExprs that are created
/// recursively during typo correction and wipe them away if the correction
/// fails.
llvm::SmallVector<TypoExpr *, 2> TypoExprs;

/// pragma clang section kind
enum PragmaClangSectionKind {
  PCSK_Invalid      = 0,
  PCSK_BSS          = 1,
  PCSK_Data         = 2,
  PCSK_Rodata       = 3,
  PCSK_Text         = 4,
  PCSK_Relro        = 5
 };

enum PragmaClangSectionAction {
  PCSA_Set     = 0,
  PCSA_Clear   = 1
};

struct PragmaClangSection {
  std::string SectionName;
  bool Valid = false;
  SourceLocation PragmaLocation;
};

 PragmaClangSection PragmaClangBSSSection;
 PragmaClangSection PragmaClangDataSection;
 PragmaClangSection PragmaClangRodataSection;
 PragmaClangSection PragmaClangRelroSection;
 PragmaClangSection PragmaClangTextSection;

enum PragmaMsStackAction {
  PSK_Reset     = 0x0,                // #pragma ()
  PSK_Set       = 0x1,                // #pragma (value)
  PSK_Push      = 0x2,                // #pragma (push[, id])
  PSK_Pop       = 0x4,                // #pragma (pop[, id])
  PSK_Show      = 0x8,                // #pragma (show) -- only for "pack"!
  PSK_Push_Set  = PSK_Push | PSK_Set, // #pragma (push[, id], value)
  PSK_Pop_Set   = PSK_Pop | PSK_Set,  // #pragma (pop[, id], value)
};

// #pragma pack and align.
class AlignPackInfo {
public:
  // `Native` represents default align mode, which may vary based on the
  // platform.
  enum Mode : unsigned char { Native, Natural, Packed, Mac68k };

  // #pragma pack info constructor
  AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
      : PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
    assert(Num == PackNumber && "The pack number has been truncated.")((void)0);
  }

  // #pragma align info constructor
  AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
      : PackAttr(false), AlignMode(M),
        PackNumber(M == Packed ? 1 : UninitPackVal), XLStack(IsXL) {}

  explicit AlignPackInfo(bool IsXL) : AlignPackInfo(Native, IsXL) {}

  AlignPackInfo() : AlignPackInfo(Native, false) {}

  // When a AlignPackInfo itself cannot be used, this returns an 32-bit
  // integer encoding for it. This should only be passed to
  // AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
  static uint32_t getRawEncoding(const AlignPackInfo &Info) {
    std::uint32_t Encoding{};
    if (Info.IsXLStack())
      Encoding |= IsXLMask;

    Encoding |= static_cast<uint32_t>(Info.getAlignMode()) << 1;

    if (Info.IsPackAttr())
      Encoding |= PackAttrMask;

    Encoding |= static_cast<uint32_t>(Info.getPackNumber()) << 4;

    return Encoding;
  }

  static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
    bool IsXL = static_cast<bool>(Encoding & IsXLMask);
    AlignPackInfo::Mode M =
        static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> 1);
    int PackNumber = (Encoding & PackNumMask) >> 4;

    if (Encoding & PackAttrMask)
      return AlignPackInfo(M, PackNumber, IsXL);

    return AlignPackInfo(M, IsXL);
  }

  bool IsPackAttr() const { return PackAttr; }

  bool IsAlignAttr() const { return !PackAttr; }

  Mode getAlignMode() const { return AlignMode; }

  unsigned getPackNumber() const { return PackNumber; }

  bool IsPackSet() const {
    // #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
    // attriute on a decl.
    return PackNumber != UninitPackVal && PackNumber != 0;
  }

  bool IsXLStack() const { return XLStack; }

  bool operator==(const AlignPackInfo &Info) const {
    return std::tie(AlignMode, PackNumber, PackAttr, XLStack) ==
           std::tie(Info.AlignMode, Info.PackNumber, Info.PackAttr,
                    Info.XLStack);
  }

  bool operator!=(const AlignPackInfo &Info) const {
    return !(*this == Info);
  }

private:
  /// \brief True if this is a pragma pack attribute,
  ///         not a pragma align attribute.
  bool PackAttr;

  /// \brief The alignment mode that is in effect.
  Mode AlignMode;

  /// \brief The pack number of the stack.
  unsigned char PackNumber;

  /// \brief True if it is a XL #pragma align/pack stack.
  bool XLStack;

  /// \brief Uninitialized pack value.
  static constexpr unsigned char UninitPackVal = -1;

  // Masks to encode and decode an AlignPackInfo.
  static constexpr uint32_t IsXLMask{0x0000'0001};
  static constexpr uint32_t AlignModeMask{0x0000'0006};
  static constexpr uint32_t PackAttrMask{0x00000'0008};
  static constexpr uint32_t PackNumMask{0x0000'01F0};
};

template<typename ValueType>
struct PragmaStack {
  struct Slot {
    llvm::StringRef StackSlotLabel;
    ValueType Value;
    SourceLocation PragmaLocation;
    SourceLocation PragmaPushLocation;
    Slot(llvm::StringRef StackSlotLabel, ValueType Value,
         SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
        : StackSlotLabel(StackSlotLabel), Value(Value),
          PragmaLocation(PragmaLocation),
          PragmaPushLocation(PragmaPushLocation) {}
  };

  void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
           llvm::StringRef StackSlotLabel, ValueType Value) {
    if (Action == PSK_Reset) {
      CurrentValue = DefaultValue;
      CurrentPragmaLocation = PragmaLocation;
      return;
    }
    if (Action & PSK_Push)
      Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
                         PragmaLocation);
    else if (Action & PSK_Pop) {
      if (!StackSlotLabel.empty()) {
        // If we've got a label, try to find it and jump there.
        auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
          return x.StackSlotLabel == StackSlotLabel;
        });
        // If we found the label so pop from there.
        if (I != Stack.rend()) {
          CurrentValue = I->Value;
          CurrentPragmaLocation = I->PragmaLocation;
          Stack.erase(std::prev(I.base()), Stack.end());
        }
      } else if (!Stack.empty()) {
        // We do not have a label, just pop the last entry.
        CurrentValue = Stack.back().Value;
        CurrentPragmaLocation = Stack.back().PragmaLocation;
        Stack.pop_back();
      }
    }
    if (Action & PSK_Set) {
      CurrentValue = Value;
      CurrentPragmaLocation = PragmaLocation;
    }
  }

  // MSVC seems to add artificial slots to #pragma stacks on entering a C++
  // method body to restore the stacks on exit, so it works like this:
  //
  //   struct S {
  //     #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
  //     void Method {}
  //     #pragma <name>(pop, InternalPragmaSlot)
  //   };
  //
  // It works even with #pragma vtordisp, although MSVC doesn't support
  //   #pragma vtordisp(push [, id], n)
  // syntax.
  //
  // Push / pop a named sentinel slot.
  void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
    assert((Action == PSK_Push || Action == PSK_Pop) &&((void)0)
           "Can only push / pop #pragma stack sentinels!")((void)0);
    Act(CurrentPragmaLocation, Action, Label, CurrentValue);
  }

  // Constructors.
  explicit PragmaStack(const ValueType &Default)
      : DefaultValue(Default), CurrentValue(Default) {}

  bool hasValue() const { return CurrentValue != DefaultValue; }

  SmallVector<Slot, 2> Stack;
  ValueType DefaultValue; // Value used for PSK_Reset action.
  ValueType CurrentValue;
  SourceLocation CurrentPragmaLocation;
};
// FIXME: We should serialize / deserialize these if they occur in a PCH (but
// we shouldn't do so if they're in a module).

/// Whether to insert vtordisps prior to virtual bases in the Microsoft
/// C++ ABI.  Possible values are 0, 1, and 2, which mean:
///
/// 0: Suppress all vtordisps
/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
///    structors
/// 2: Always insert vtordisps to support RTTI on partially constructed
///    objects
PragmaStack<MSVtorDispMode> VtorDispStack;
PragmaStack<AlignPackInfo> AlignPackStack;
// The current #pragma align/pack values and locations at each #include.
struct AlignPackIncludeState {
  AlignPackInfo CurrentValue;
  SourceLocation CurrentPragmaLocation;
  bool HasNonDefaultValue, ShouldWarnOnInclude;
};
SmallVector<AlignPackIncludeState, 8> AlignPackIncludeStack;
// Segment #pragmas.
PragmaStack<StringLiteral *> DataSegStack;
PragmaStack<StringLiteral *> BSSSegStack;
PragmaStack<StringLiteral *> ConstSegStack;
PragmaStack<StringLiteral *> CodeSegStack;

// This stack tracks the current state of Sema.CurFPFeatures.
PragmaStack<FPOptionsOverride> FpPragmaStack;
FPOptionsOverride CurFPFeatureOverrides() {
  FPOptionsOverride result;
  if (!FpPragmaStack.hasValue()) {
    result = FPOptionsOverride();
  } else {
    result = FpPragmaStack.CurrentValue;
  }
  return result;
}

// RAII object to push / pop sentinel slots for all MS #pragma stacks.
// Actions should be performed only if we enter / exit a C++ method body.
class PragmaStackSentinelRAII {
public:
  PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
  ~PragmaStackSentinelRAII();

private:
  Sema &S;
  StringRef SlotLabel;
  bool ShouldAct;
};

/// A mapping that describes the nullability we've seen in each header file.
FileNullabilityMap NullabilityMap;

/// Last section used with #pragma init_seg.
StringLiteral *CurInitSeg;
SourceLocation CurInitSegLoc;

/// VisContext - Manages the stack for \#pragma GCC visibility.
void *VisContext; // Really a "PragmaVisStack*"

/// This an attribute introduced by \#pragma clang attribute.
struct PragmaAttributeEntry {
  SourceLocation Loc;
  ParsedAttr *Attribute;
  SmallVector<attr::SubjectMatchRule, 4> MatchRules;
  bool IsUsed;
};

/// A push'd group of PragmaAttributeEntries.
struct PragmaAttributeGroup {
  /// The location of the push attribute.
  SourceLocation Loc;
  /// The namespace of this push group.
  const IdentifierInfo *Namespace;
  SmallVector<PragmaAttributeEntry, 2> Entries;
};

SmallVector<PragmaAttributeGroup, 2> PragmaAttributeStack;

/// The declaration that is currently receiving an attribute from the
/// #pragma attribute stack.
const Decl *PragmaAttributeCurrentTargetDecl;

/// This represents the last location of a "#pragma clang optimize off"
/// directive if such a directive has not been closed by an "on" yet. If
/// optimizations are currently "on", this is set to an invalid location.
SourceLocation OptimizeOffPragmaLocation;

/// Flag indicating if Sema is building a recovery call expression.
///
/// This flag is used to avoid building recovery call expressions
/// if Sema is already doing so, which would cause infinite recursions.
bool IsBuildingRecoveryCallExpr;

/// Used to control the generation of ExprWithCleanups.
CleanupInfo Cleanup;

/// ExprCleanupObjects - This is the stack of objects requiring
/// cleanup that are created by the current full expression.
SmallVector<ExprWithCleanups::CleanupObject, 8> ExprCleanupObjects;

/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
/// to a variable (constant) that may or may not be odr-used in this Expr, and
/// we won't know until all lvalue-to-rvalue and discarded value conversions
/// have been applied to all subexpressions of the enclosing full expression.
/// This is cleared at the end of each full expression.
using MaybeODRUseExprSet = llvm::SetVector<Expr *, SmallVector<Expr *, 4>,
                                           llvm::SmallPtrSet<Expr *, 4>>;
MaybeODRUseExprSet MaybeODRUseExprs;

std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;

/// Stack containing information about each of the nested
/// function, block, and method scopes that are currently active.
SmallVector<sema::FunctionScopeInfo *, 4> FunctionScopes;

/// The index of the first FunctionScope that corresponds to the current
/// context.
unsigned FunctionScopesStart = 0;

ArrayRef<sema::FunctionScopeInfo*> getFunctionScopes() const {
  return llvm::makeArrayRef(FunctionScopes.begin() + FunctionScopesStart,
                            FunctionScopes.end());
}

/// Stack containing information needed when in C++2a an 'auto' is encountered
/// in a function declaration parameter type specifier in order to invent a
/// corresponding template parameter in the enclosing abbreviated function
/// template. This information is also present in LambdaScopeInfo, stored in
/// the FunctionScopes stack.
SmallVector<InventedTemplateParameterInfo, 4> InventedParameterInfos;

/// The index of the first InventedParameterInfo that refers to the current
/// context.
unsigned InventedParameterInfosStart = 0;

ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
  return llvm::makeArrayRef(InventedParameterInfos.begin() +
                                InventedParameterInfosStart,
                            InventedParameterInfos.end());
}

typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadExtVectorDecls, 2, 2>
  ExtVectorDeclsType;

/// ExtVectorDecls - This is a list all the extended vector types. This allows
/// us to associate a raw vector type with one of the ext_vector type names.
/// This is only necessary for issuing pretty diagnostics.
ExtVectorDeclsType ExtVectorDecls;

/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
std::unique_ptr<CXXFieldCollector> FieldCollector;

typedef llvm::SmallSetVector<NamedDecl *, 16> NamedDeclSetType;

/// Set containing all declared private fields that are not used.
NamedDeclSetType UnusedPrivateFields;

/// Set containing all typedefs that are likely unused.
llvm::SmallSetVector<const TypedefNameDecl *, 4>
    UnusedLocalTypedefNameCandidates;

/// Delete-expressions to be analyzed at the end of translation unit
///
/// This list contains class members, and locations of delete-expressions
/// that could not be proven as to whether they mismatch with new-expression
/// used in initializer of the field.
typedef std::pair<SourceLocation, bool> DeleteExprLoc;
typedef llvm::SmallVector<DeleteExprLoc, 4> DeleteLocs;
llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;

typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;

/// PureVirtualClassDiagSet - a set of class declarations which we have
/// emitted a list of pure virtual functions. Used to prevent emitting the
/// same list more than once.
std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;

/// ParsingInitForAutoVars - a set of declarations with auto types for which
/// we are currently parsing the initializer.
llvm::SmallPtrSet<const Decl*, 4> ParsingInitForAutoVars;

/// Look for a locally scoped extern "C" declaration by the given name.
NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);

typedef LazyVector<VarDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadTentativeDefinitions, 2, 2>
  TentativeDefinitionsType;

/// All the tentative definitions encountered in the TU.
TentativeDefinitionsType TentativeDefinitions;

/// All the external declarations encoutered and used in the TU.
SmallVector<VarDecl *, 4> ExternalDeclarations;

typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadUnusedFileScopedDecls, 2, 2>
  UnusedFileScopedDeclsType;

/// The set of file scoped decls seen so far that have not been used
/// and must warn if not used. Only contains the first declaration.
UnusedFileScopedDeclsType UnusedFileScopedDecls;

typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadDelegatingConstructors, 2, 2>
  DelegatingCtorDeclsType;

/// All the delegating constructors seen so far in the file, used for
/// cycle detection at the end of the TU.
DelegatingCtorDeclsType DelegatingCtorDecls;

/// All the overriding functions seen during a class definition
/// that had their exception spec checks delayed, plus the overridden
/// function.
SmallVector<std::pair<const CXXMethodDecl*, const CXXMethodDecl*>, 2>
  DelayedOverridingExceptionSpecChecks;

/// All the function redeclarations seen during a class definition that had
/// their exception spec checks delayed, plus the prior declaration they
/// should be checked against. Except during error recovery, the new decl
/// should always be a friend declaration, as that's the only valid way to
/// redeclare a special member before its class is complete.
SmallVector<std::pair<FunctionDecl*, FunctionDecl*>, 2>
  DelayedEquivalentExceptionSpecChecks;

typedef llvm::MapVector<const FunctionDecl *,
                        std::unique_ptr<LateParsedTemplate>>
    LateParsedTemplateMapT;
LateParsedTemplateMapT LateParsedTemplateMap;

/// Callback to the parser to parse templated functions when needed.
typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
typedef void LateTemplateParserCleanupCB(void *P);
LateTemplateParserCB *LateTemplateParser;
LateTemplateParserCleanupCB *LateTemplateParserCleanup;
void *OpaqueParser;

void SetLateTemplateParser(LateTemplateParserCB *LTP,
                           LateTemplateParserCleanupCB *LTPCleanup,
                           void *P) {
  LateTemplateParser = LTP;
  LateTemplateParserCleanup = LTPCleanup;
  OpaqueParser = P;
}

// Does the work necessary to deal with a SYCL kernel lambda. At the moment,
// this just marks the list of lambdas required to name the kernel.
void AddSYCLKernelLambda(const FunctionDecl *FD);

class DelayedDiagnostics;

class DelayedDiagnosticsState {
  sema::DelayedDiagnosticPool *SavedPool;
  friend class Sema::DelayedDiagnostics;
};
typedef DelayedDiagnosticsState ParsingDeclState;
typedef DelayedDiagnosticsState ProcessingContextState;

/// A class which encapsulates the logic for delaying diagnostics
/// during parsing and other processing.
class DelayedDiagnostics {
  /// The current pool of diagnostics into which delayed
  /// diagnostics should go.
  sema::DelayedDiagnosticPool *CurPool;

public:
  DelayedDiagnostics() : CurPool(nullptr) {}

  /// Adds a delayed diagnostic.
  void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h

  /// Determines whether diagnostics should be delayed.
  bool shouldDelayDiagnostics() { return CurPool != nullptr; }

  /// Returns the current delayed-diagnostics pool.
  sema::DelayedDiagnosticPool *getCurrentPool() const {
    return CurPool;
  }

  /// Enter a new scope.  Access and deprecation diagnostics will be
  /// collected in this pool.
  DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = &pool;
    return state;
  }

  /// Leave a delayed-diagnostic state that was previously pushed.
  /// Do not emit any of the diagnostics.  This is performed as part
  /// of the bookkeeping of popping a pool "properly".
  void popWithoutEmitting(DelayedDiagnosticsState state) {
    CurPool = state.SavedPool;
  }

  /// Enter a new scope where access and deprecation diagnostics are
  /// not delayed.
  DelayedDiagnosticsState pushUndelayed() {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = nullptr;
    return state;
  }

  /// Undo a previous pushUndelayed().
  void popUndelayed(DelayedDiagnosticsState state) {
    assert(CurPool == nullptr)((void)0);
    CurPool = state.SavedPool;
  }
} DelayedDiagnostics;

/// A RAII object to temporarily push a declaration context.
class ContextRAII {
private:
  Sema &S;
  DeclContext *SavedContext;
  ProcessingContextState SavedContextState;
  QualType SavedCXXThisTypeOverride;
  unsigned SavedFunctionScopesStart;
  unsigned SavedInventedParameterInfosStart;

public:
  ContextRAII(Sema &S, DeclContext *ContextToPush, bool NewThisContext = true)
    : S(S), SavedContext(S.CurContext),
      SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
      SavedCXXThisTypeOverride(S.CXXThisTypeOverride),
      SavedFunctionScopesStart(S.FunctionScopesStart),
      SavedInventedParameterInfosStart(S.InventedParameterInfosStart)
  {
    assert(ContextToPush && "pushing null context")((void)0);
    S.CurContext = ContextToPush;
    if (NewThisContext)
      S.CXXThisTypeOverride = QualType();
    // Any saved FunctionScopes do not refer to this context.
    S.FunctionScopesStart = S.FunctionScopes.size();
    S.InventedParameterInfosStart = S.InventedParameterInfos.size();
  }

  void pop() {
    if (!SavedContext) return;
    S.CurContext = SavedContext;
    S.DelayedDiagnostics.popUndelayed(SavedContextState);
    S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
    S.FunctionScopesStart = SavedFunctionScopesStart;
    S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
    SavedContext = nullptr;
  }

  ~ContextRAII() {
    pop();
  }
};

/// Whether the AST is currently being rebuilt to correct immediate
/// invocations. Immediate invocation candidates and references to consteval
/// functions aren't tracked when this is set.
bool RebuildingImmediateInvocation = false;

/// Used to change context to isConstantEvaluated without pushing a heavy
/// ExpressionEvaluationContextRecord object.
bool isConstantEvaluatedOverride;

bool isConstantEvaluated() {
  return ExprEvalContexts.back().isConstantEvaluated() ||
         isConstantEvaluatedOverride;
}

/// RAII object to handle the state changes required to synthesize
/// a function body.
class SynthesizedFunctionScope {
  Sema &S;
  Sema::ContextRAII SavedContext;
  bool PushedCodeSynthesisContext = false;

public:
  SynthesizedFunctionScope(Sema &S, DeclContext *DC)
      : S(S), SavedContext(S, DC) {
    S.PushFunctionScope();
    S.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
    if (auto *FD = dyn_cast<FunctionDecl>(DC))
      FD->setWillHaveBody(true);
    else
      assert(isa<ObjCMethodDecl>(DC))((void)0);
  }

  void addContextNote(SourceLocation UseLoc) {
    assert(!PushedCodeSynthesisContext)((void)0);

    Sema::CodeSynthesisContext Ctx;
    Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
    Ctx.PointOfInstantiation = UseLoc;
    Ctx.Entity = cast<Decl>(S.CurContext);
    S.pushCodeSynthesisContext(Ctx);

    PushedCodeSynthesisContext = true;
  }

  ~SynthesizedFunctionScope() {
    if (PushedCodeSynthesisContext)
      S.popCodeSynthesisContext();
    if (auto *FD = dyn_cast<FunctionDecl>(S.CurContext))
      FD->setWillHaveBody(false);
    S.PopExpressionEvaluationContext();
    S.PopFunctionScopeInfo();
  }
};

/// WeakUndeclaredIdentifiers - Identifiers contained in
/// \#pragma weak before declared. rare. may alias another
/// identifier, declared or undeclared
llvm::MapVector<IdentifierInfo *, WeakInfo> WeakUndeclaredIdentifiers;

/// ExtnameUndeclaredIdentifiers - Identifiers contained in
/// \#pragma redefine_extname before declared.  Used in Solaris system headers
/// to define functions that occur in multiple standards to call the version
/// in the currently selected standard.
llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*> ExtnameUndeclaredIdentifiers;


/// Load weak undeclared identifiers from the external source.
void LoadExternalWeakUndeclaredIdentifiers();

/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
/// \#pragma weak during processing of other Decls.
/// I couldn't figure out a clean way to generate these in-line, so
/// we store them here and handle separately -- which is a hack.
/// It would be best to refactor this.
SmallVector<Decl*,2> WeakTopLevelDecl;

IdentifierResolver IdResolver;

/// Translation Unit Scope - useful to Objective-C actions that need
/// to lookup file scope declarations in the "ordinary" C decl namespace.
/// For example, user-defined classes, built-in "id" type, etc.
Scope *TUScope;

/// The C++ "std" namespace, where the standard library resides.
LazyDeclPtr StdNamespace;

/// The C++ "std::bad_alloc" class, which is defined by the C++
/// standard library.
LazyDeclPtr StdBadAlloc;

/// The C++ "std::align_val_t" enum class, which is defined by the C++
/// standard library.
LazyDeclPtr StdAlignValT;

/// The C++ "std::experimental" namespace, where the experimental parts
/// of the standard library resides.
NamespaceDecl *StdExperimentalNamespaceCache;

/// The C++ "std::initializer_list" template, which is defined in
/// \<initializer_list>.
ClassTemplateDecl *StdInitializerList;

/// The C++ "std::coroutine_traits" template, which is defined in
/// \<coroutine_traits>
ClassTemplateDecl *StdCoroutineTraitsCache;

/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
RecordDecl *CXXTypeInfoDecl;

/// The MSVC "_GUID" struct, which is defined in MSVC header files.
RecordDecl *MSVCGuidDecl;

/// Caches identifiers/selectors for NSFoundation APIs.
std::unique_ptr<NSAPI> NSAPIObj;

/// The declaration of the Objective-C NSNumber class.
ObjCInterfaceDecl *NSNumberDecl;

/// The declaration of the Objective-C NSValue class.
ObjCInterfaceDecl *NSValueDecl;

/// Pointer to NSNumber type (NSNumber *).
QualType NSNumberPointer;

/// Pointer to NSValue type (NSValue *).
QualType NSValuePointer;

/// The Objective-C NSNumber methods used to create NSNumber literals.
ObjCMethodDecl *NSNumberLiteralMethods[NSAPI::NumNSNumberLiteralMethods];

/// The declaration of the Objective-C NSString class.
ObjCInterfaceDecl *NSStringDecl;

/// Pointer to NSString type (NSString *).
QualType NSStringPointer;

/// The declaration of the stringWithUTF8String: method.
ObjCMethodDecl *StringWithUTF8StringMethod;

/// The declaration of the valueWithBytes:objCType: method.
ObjCMethodDecl *ValueWithBytesObjCTypeMethod;

/// The declaration of the Objective-C NSArray class.
ObjCInterfaceDecl *NSArrayDecl;

/// The declaration of the arrayWithObjects:count: method.
ObjCMethodDecl *ArrayWithObjectsMethod;

/// The declaration of the Objective-C NSDictionary class.
ObjCInterfaceDecl *NSDictionaryDecl;

/// The declaration of the dictionaryWithObjects:forKeys:count: method.
ObjCMethodDecl *DictionaryWithObjectsMethod;

/// id<NSCopying> type.
QualType QIDNSCopying;

/// will hold 'respondsToSelector:'
Selector RespondsToSelectorSel;

/// A flag to remember whether the implicit forms of operator new and delete
/// have been declared.
bool GlobalNewDeleteDeclared;

/// Describes how the expressions currently being parsed are
/// evaluated at run-time, if at all.
enum class ExpressionEvaluationContext {
  /// The current expression and its subexpressions occur within an
  /// unevaluated operand (C++11 [expr]p7), such as the subexpression of
  /// \c sizeof, where the type of the expression may be significant but
  /// no code will be generated to evaluate the value of the expression at
  /// run time.
  Unevaluated,

  /// The current expression occurs within a braced-init-list within
  /// an unevaluated operand. This is mostly like a regular unevaluated
  /// context, except that we still instantiate constexpr functions that are
  /// referenced here so that we can perform narrowing checks correctly.
  UnevaluatedList,

  /// The current expression occurs within a discarded statement.
  /// This behaves largely similarly to an unevaluated operand in preventing
  /// definitions from being required, but not in other ways.
  DiscardedStatement,

  /// The current expression occurs within an unevaluated
  /// operand that unconditionally permits abstract references to
  /// fields, such as a SIZE operator in MS-style inline assembly.
  UnevaluatedAbstract,

  /// The current context is "potentially evaluated" in C++11 terms,
  /// but the expression is evaluated at compile-time (like the values of
  /// cases in a switch statement).
  ConstantEvaluated,

  /// The current expression is potentially evaluated at run time,
  /// which means that code may be generated to evaluate the value of the
  /// expression at run time.
  PotentiallyEvaluated,

  /// The current expression is potentially evaluated, but any
  /// declarations referenced inside that expression are only used if
  /// in fact the current expression is used.
  ///
  /// This value is used when parsing default function arguments, for which
  /// we would like to provide diagnostics (e.g., passing non-POD arguments
  /// through varargs) but do not want to mark declarations as "referenced"
  /// until the default argument is used.
  PotentiallyEvaluatedIfUsed
};

using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, 1>;

/// Data structure used to record current or nested
/// expression evaluation contexts.
struct ExpressionEvaluationContextRecord {
  /// The expression evaluation context.
  ExpressionEvaluationContext Context;

  /// Whether the enclosing context needed a cleanup.
  CleanupInfo ParentCleanup;

  /// The number of active cleanup objects when we entered
  /// this expression evaluation context.
  unsigned NumCleanupObjects;

  /// The number of typos encountered during this expression evaluation
  /// context (i.e. the number of TypoExprs created).
  unsigned NumTypos;

  MaybeODRUseExprSet SavedMaybeODRUseExprs;

  /// The lambdas that are present within this context, if it
  /// is indeed an unevaluated context.
  SmallVector<LambdaExpr *, 2> Lambdas;

  /// The declaration that provides context for lambda expressions
  /// and block literals if the normal declaration context does not
  /// suffice, e.g., in a default function argument.
  Decl *ManglingContextDecl;

  /// If we are processing a decltype type, a set of call expressions
  /// for which we have deferred checking the completeness of the return type.
  SmallVector<CallExpr *, 8> DelayedDecltypeCalls;

  /// If we are processing a decltype type, a set of temporary binding
  /// expressions for which we have deferred checking the destructor.
  SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;

  llvm::SmallPtrSet<const Expr *, 8> PossibleDerefs;

  /// Expressions appearing as the LHS of a volatile assignment in this
  /// context. We produce a warning for these when popping the context if
  /// they are not discarded-value expressions nor unevaluated operands.
  SmallVector<Expr*, 2> VolatileAssignmentLHSs;

  /// Set of candidates for starting an immediate invocation.
  llvm::SmallVector<ImmediateInvocationCandidate, 4> ImmediateInvocationCandidates;

  /// Set of DeclRefExprs referencing a consteval function when used in a
  /// context not already known to be immediately invoked.
  llvm::SmallPtrSet<DeclRefExpr *, 4> ReferenceToConsteval;

  /// \brief Describes whether we are in an expression constext which we have
  /// to handle differently.
  enum ExpressionKind {
    EK_Decltype, EK_TemplateArgument, EK_Other
  } ExprContext;

  ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                    unsigned NumCleanupObjects,
                                    CleanupInfo ParentCleanup,
                                    Decl *ManglingContextDecl,
                                    ExpressionKind ExprContext)
      : Context(Context), ParentCleanup(ParentCleanup),
        NumCleanupObjects(NumCleanupObjects), NumTypos(0),
        ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext) {}

  bool isUnevaluated() const {
    return Context == ExpressionEvaluationContext::Unevaluated ||
           Context == ExpressionEvaluationContext::UnevaluatedAbstract ||
           Context == ExpressionEvaluationContext::UnevaluatedList;
  }
  bool isConstantEvaluated() const {
    return Context == ExpressionEvaluationContext::ConstantEvaluated;
  }
};

/// A stack of expression evaluation contexts.
SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;

/// Emit a warning for all pending noderef expressions that we recorded.
void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);

/// Compute the mangling number context for a lambda expression or
/// block literal. Also return the extra mangling decl if any.
///
/// \param DC - The DeclContext containing the lambda expression or
/// block literal.
std::tuple<MangleNumberingContext *, Decl *>
getCurrentMangleNumberContext(const DeclContext *DC);


/// SpecialMemberOverloadResult - The overloading result for a special member
/// function.
///
/// This is basically a wrapper around PointerIntPair. The lowest bits of the
/// integer are used to determine whether overload resolution succeeded.
class SpecialMemberOverloadResult {
public:
  enum Kind {
    NoMemberOrDeleted,
    Ambiguous,
    Success
  };

private:
  llvm::PointerIntPair<CXXMethodDecl*, 2> Pair;

public:
  SpecialMemberOverloadResult() : Pair() {}
  SpecialMemberOverloadResult(CXXMethodDecl *MD)
      : Pair(MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}

  CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
  void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }

  Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
  void setKind(Kind K) { Pair.setInt(K); }
};

class SpecialMemberOverloadResultEntry
    : public llvm::FastFoldingSetNode,
      public SpecialMemberOverloadResult {
public:
  SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
    : FastFoldingSetNode(ID)
  {}
};

/// A cache of special member function overload resolution results
/// for C++ records.
llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;

/// A cache of the flags available in enumerations with the flag_bits
/// attribute.
mutable llvm::DenseMap<const EnumDecl*, llvm::APInt> FlagBitsCache;

/// The kind of translation unit we are processing.
///
/// When we're processing a complete translation unit, Sema will perform
/// end-of-translation-unit semantic tasks (such as creating
/// initializers for tentative definitions in C) once parsing has
/// completed. Modules and precompiled headers perform different kinds of
/// checks.
const TranslationUnitKind TUKind;

llvm::BumpPtrAllocator BumpAlloc;

/// The number of SFINAE diagnostics that have been trapped.
unsigned NumSFINAEErrors;

typedef llvm::DenseMap<ParmVarDecl *, llvm::TinyPtrVector<ParmVarDecl *>>
  UnparsedDefaultArgInstantiationsMap;

/// A mapping from parameters with unparsed default arguments to the
/// set of instantiations of each parameter.
///
/// This mapping is a temporary data structure used when parsing
/// nested class templates or nested classes of class templates,
/// where we might end up instantiating an inner class before the
/// default arguments of its methods have been parsed.
UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;

// Contains the locations of the beginning of unparsed default
// argument locations.
llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;

/// UndefinedInternals - all the used, undefined objects which require a
/// definition in this translation unit.
llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;

/// Determine if VD, which must be a variable or function, is an external
/// symbol that nonetheless can't be referenced from outside this translation
/// unit because its type has no linkage and it's not extern "C".
bool isExternalWithNoLinkageType(ValueDecl *VD);

/// Obtain a sorted list of functions that are undefined but ODR-used.
void getUndefinedButUsed(
    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);

/// Retrieves list of suspicious delete-expressions that will be checked at
/// the end of translation unit.
const llvm::MapVector<FieldDecl *, DeleteLocs> &
getMismatchingDeleteExpressions() const;

typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
typedef llvm::DenseMap<Selector, GlobalMethods> GlobalMethodPool;

/// Method Pool - allows efficient lookup when typechecking messages to "id".
/// We need to maintain a list, since selectors can have differing signatures
/// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
/// of selectors are "overloaded").
/// At the head of the list it is recorded whether there were 0, 1, or >= 2
/// methods inside categories with a particular selector.
GlobalMethodPool MethodPool;

/// Method selectors used in a \@selector expression. Used for implementation
/// of -Wselector.
llvm::MapVector<Selector, SourceLocation> ReferencedSelectors;

/// List of SourceLocations where 'self' is implicitly retained inside a
/// block.
llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, 1>
    ImplicitlyRetainedSelfLocs;

/// Kinds of C++ special members.
enum CXXSpecialMember {
  CXXDefaultConstructor,
  CXXCopyConstructor,
  CXXMoveConstructor,
  CXXCopyAssignment,
  CXXMoveAssignment,
  CXXDestructor,
  CXXInvalid
};

typedef llvm::PointerIntPair<CXXRecordDecl *, 3, CXXSpecialMember>
    SpecialMemberDecl;

/// The C++ special members which we are currently in the process of
/// declaring. If this process recursively triggers the declaration of the
/// same special member, we should act as if it is not yet declared.
llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;

/// Kinds of defaulted comparison operator functions.
enum class DefaultedComparisonKind : unsigned char {
  /// This is not a defaultable comparison operator.
  None,
  /// This is an operator== that should be implemented as a series of
  /// subobject comparisons.
  Equal,
  /// This is an operator<=> that should be implemented as a series of
  /// subobject comparisons.
  ThreeWay,
  /// This is an operator!= that should be implemented as a rewrite in terms
  /// of a == comparison.
  NotEqual,
  /// This is an <, <=, >, or >= that should be implemented as a rewrite in
  /// terms of a <=> comparison.
  Relational,
};

/// The function definitions which were renamed as part of typo-correction
/// to match their respective declarations. We want to keep track of them
/// to ensure that we don't emit a "redefinition" error if we encounter a
/// correctly named definition after the renamed definition.
llvm::SmallPtrSet<const NamedDecl *, 4> TypoCorrectedFunctionDefinitions;

/// Stack of types that correspond to the parameter entities that are
/// currently being copy-initialized. Can be empty.
llvm::SmallVector<QualType, 4> CurrentParameterCopyTypes;

void ReadMethodPool(Selector Sel);
void updateOutOfDateSelector(Selector Sel);

/// Private Helper predicate to check for 'self'.
bool isSelfExpr(Expr *RExpr);
bool isSelfExpr(Expr *RExpr, const ObjCMethodDecl *Method);

/// Cause the active diagnostic on the DiagosticsEngine to be
/// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
/// should not be used elsewhere.
void EmitCurrentDiagnostic(unsigned DiagID);

/// Records and restores the CurFPFeatures state on entry/exit of compound
/// statements.
class FPFeaturesStateRAII {
public:
  FPFeaturesStateRAII(Sema &S) : S(S), OldFPFeaturesState(S.CurFPFeatures) {
    OldOverrides = S.FpPragmaStack.CurrentValue;
  }
  ~FPFeaturesStateRAII() {
    S.CurFPFeatures = OldFPFeaturesState;
    S.FpPragmaStack.CurrentValue = OldOverrides;
  }
  FPOptionsOverride getOverrides() { return OldOverrides; }

private:
  Sema& S;
  FPOptions OldFPFeaturesState;
  FPOptionsOverride OldOverrides;
};

void addImplicitTypedef(StringRef Name, QualType T);

bool WarnedStackExhausted = false;

/// Increment when we find a reference; decrement when we find an ignored
/// assignment.  Ultimately the value is 0 if every reference is an ignored
/// assignment.
llvm::DenseMap<const VarDecl *, int> RefsMinusAssignments;

Optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;

1531public:
Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     TranslationUnitKind TUKind = TU_Complete,
     CodeCompleteConsumer *CompletionConsumer = nullptr);
~Sema();

/// Perform initialization that occurs after the parser has been
/// initialized but before it parses anything.
void Initialize();

/// This virtual key function only exists to limit the emission of debug info
/// describing the Sema class. GCC and Clang only emit debug info for a class
/// with a vtable when the vtable is emitted. Sema is final and not
/// polymorphic, but the debug info size savings are so significant that it is
/// worth adding a vtable just to take advantage of this optimization.
virtual void anchor();

const LangOptions &getLangOpts() const { return LangOpts; }
OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
FPOptions     &getCurFPFeatures() { return CurFPFeatures; }

DiagnosticsEngine &getDiagnostics() const { return Diags; }
SourceManager &getSourceManager() const { return SourceMgr; }
Preprocessor &getPreprocessor() const { return PP; }
ASTContext &getASTContext() const { return Context; }
ASTConsumer &getASTConsumer() const { return Consumer; }
ASTMutationListener *getASTMutationListener() const;
ExternalSemaSource* getExternalSource() const { return ExternalSource; }
DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
                                                       StringRef Platform);

///Registers an external source. If an external source already exists,
/// creates a multiplex external source and appends to it.
///
///\param[in] E - A non-null external sema source.
///
void addExternalSource(ExternalSemaSource *E);

void PrintStats() const;

/// Warn that the stack is nearly exhausted.
void warnStackExhausted(SourceLocation Loc);

/// Run some code with "sufficient" stack space. (Currently, at least 256K is
/// guaranteed). Produces a warning if we're low on stack space and allocates
/// more in that case. Use this in code that may recurse deeply (for example,
/// in template instantiation) to avoid stack overflow.
void runWithSufficientStackSpace(SourceLocation Loc,
                                 llvm::function_ref<void()> Fn);

/// Helper class that creates diagnostics with optional
/// template instantiation stacks.
///
/// This class provides a wrapper around the basic DiagnosticBuilder
/// class that emits diagnostics. ImmediateDiagBuilder is
/// responsible for emitting the diagnostic (as DiagnosticBuilder
/// does) and, if the diagnostic comes from inside a template
/// instantiation, printing the template instantiation stack as
/// well.
class ImmediateDiagBuilder : public DiagnosticBuilder {
  Sema &SemaRef;
  unsigned DiagID;

public:
  ImmediateDiagBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}
  ImmediateDiagBuilder(DiagnosticBuilder &&DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}

  // This is a cunning lie. DiagnosticBuilder actually performs move
  // construction in its copy constructor (but due to varied uses, it's not
  // possible to conveniently express this as actual move construction). So
  // the default copy ctor here is fine, because the base class disables the
  // source anyway, so the user-defined ~ImmediateDiagBuilder is a safe no-op
  // in that case anwyay.
  ImmediateDiagBuilder(const ImmediateDiagBuilder &) = default;

  ~ImmediateDiagBuilder() {
    // If we aren't active, there is nothing to do.
    if (!isActive()) return;

    // Otherwise, we need to emit the diagnostic. First clear the diagnostic
    // builder itself so it won't emit the diagnostic in its own destructor.
    //
    // This seems wasteful, in that as written the DiagnosticBuilder dtor will
    // do its own needless checks to see if the diagnostic needs to be
    // emitted. However, because we take care to ensure that the builder
    // objects never escape, a sufficiently smart compiler will be able to
    // eliminate that code.
    Clear();

    // Dispatch to Sema to emit the diagnostic.
    SemaRef.EmitCurrentDiagnostic(DiagID);
  }

  /// Teach operator<< to produce an object of the correct type.
  template <typename T>
  friend const ImmediateDiagBuilder &
  operator<<(const ImmediateDiagBuilder &Diag, const T &Value) {
    const DiagnosticBuilder &BaseDiag = Diag;
    BaseDiag << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T, typename = typename std::enable_if<
                            !std::is_lvalue_reference<T>::value>::type>
  const ImmediateDiagBuilder &operator<<(T &&V) const {
    const DiagnosticBuilder &BaseDiag = *this;
    BaseDiag << std::move(V);
    return *this;
  }
};

/// A generic diagnostic builder for errors which may or may not be deferred.
///
/// In CUDA, there exist constructs (e.g. variable-length arrays, try/catch)
/// which are not allowed to appear inside __device__ functions and are
/// allowed to appear in __host__ __device__ functions only if the host+device
/// function is never codegen'ed.
///
/// To handle this, we use the notion of "deferred diagnostics", where we
/// attach a diagnostic to a FunctionDecl that's emitted iff it's codegen'ed.
///
/// This class lets you emit either a regular diagnostic, a deferred
/// diagnostic, or no diagnostic at all, according to an argument you pass to
/// its constructor, thus simplifying the process of creating these "maybe
/// deferred" diagnostics.
class SemaDiagnosticBuilder {
public:
  enum Kind {
    /// Emit no diagnostics.
    K_Nop,
    /// Emit the diagnostic immediately (i.e., behave like Sema::Diag()).
    K_Immediate,
    /// Emit the diagnostic immediately, and, if it's a warning or error, also
    /// emit a call stack showing how this function can be reached by an a
    /// priori known-emitted function.
    K_ImmediateWithCallStack,
    /// Create a deferred diagnostic, which is emitted only if the function
    /// it's attached to is codegen'ed.  Also emit a call stack as with
    /// K_ImmediateWithCallStack.
    K_Deferred
  };

  SemaDiagnosticBuilder(Kind K, SourceLocation Loc, unsigned DiagID,
                        FunctionDecl *Fn, Sema &S);
  SemaDiagnosticBuilder(SemaDiagnosticBuilder &&D);
  SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
  ~SemaDiagnosticBuilder();

  bool isImmediate() const { return ImmediateDiag.hasValue(); }

  /// Convertible to bool: True if we immediately emitted an error, false if
  /// we didn't emit an error or we created a deferred error.
  ///
  /// Example usage:
  ///
  ///   if (SemaDiagnosticBuilder(...) << foo << bar)
  ///     return ExprError();
  ///
  /// But see CUDADiagIfDeviceCode() and CUDADiagIfHostCode() -- you probably
  /// want to use these instead of creating a SemaDiagnosticBuilder yourself.
  operator bool() const { return isImmediate(); }

  template <typename T>
  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const T &Value) {
    if (Diag.ImmediateDiag.hasValue())
      *Diag.ImmediateDiag << Value;
    else if (Diag.PartialDiagId.hasValue())
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second
          << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T, typename = typename std::enable_if<
                            !std::is_lvalue_reference<T>::value>::type>
  const SemaDiagnosticBuilder &operator<<(T &&V) const {
    if (ImmediateDiag.hasValue())
      *ImmediateDiag << std::move(V);
    else if (PartialDiagId.hasValue())
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second << std::move(V);
    return *this;
  }

  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const PartialDiagnostic &PD) {
    if (Diag.ImmediateDiag.hasValue())
      PD.Emit(*Diag.ImmediateDiag);
    else if (Diag.PartialDiagId.hasValue())
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second = PD;
    return Diag;
  }

  void AddFixItHint(const FixItHint &Hint) const {
    if (ImmediateDiag.hasValue())
      ImmediateDiag->AddFixItHint(Hint);
    else if (PartialDiagId.hasValue())
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second.AddFixItHint(Hint);
  }

  friend ExprResult ExprError(const SemaDiagnosticBuilder &) {
    return ExprError();
  }
  friend StmtResult StmtError(const SemaDiagnosticBuilder &) {
    return StmtError();
  }
  operator ExprResult() const { return ExprError(); }
  operator StmtResult() const { return StmtError(); }
  operator TypeResult() const { return TypeError(); }
  operator DeclResult() const { return DeclResult(true); }
  operator MemInitResult() const { return MemInitResult(true); }

private:
  Sema &S;
  SourceLocation Loc;
  unsigned DiagID;
  FunctionDecl *Fn;
  bool ShowCallStack;

  // Invariant: At most one of these Optionals has a value.
  // FIXME: Switch these to a Variant once that exists.
  llvm::Optional<ImmediateDiagBuilder> ImmediateDiag;
  llvm::Optional<unsigned> PartialDiagId;
};

/// Is the last error level diagnostic immediate. This is used to determined
/// whether the next info diagnostic should be immediate.
bool IsLastErrorImmediate = true;

/// Emit a diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID,
                           bool DeferHint = false);

/// Emit a partial diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic &PD,
                           bool DeferHint = false);

/// Build a partial diagnostic.
PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h

/// Whether deferrable diagnostics should be deferred.
bool DeferDiags = false;

/// RAII class to control scope of DeferDiags.
class DeferDiagsRAII {
  Sema &S;
  bool SavedDeferDiags = false;

public:
  DeferDiagsRAII(Sema &S, bool DeferDiags)
      : S(S), SavedDeferDiags(S.DeferDiags) {
    S.DeferDiags = DeferDiags;
  }
  ~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
};

/// Whether uncompilable error has occurred. This includes error happens
/// in deferred diagnostics.
bool hasUncompilableErrorOccurred() const;

bool findMacroSpelling(SourceLocation &loc, StringRef name);

/// Get a string to suggest for zero-initialization of a type.
std::string
getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const;
std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;

/// Calls \c Lexer::getLocForEndOfToken()
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = 0);

/// Retrieve the module loader associated with the preprocessor.
ModuleLoader &getModuleLoader() const;

/// Invent a new identifier for parameters of abbreviated templates.
IdentifierInfo *
InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
                                           unsigned Index);

void emitAndClearUnusedLocalTypedefWarnings();

private:
  /// Function or variable declarations to be checked for whether the deferred
  /// diagnostics should be emitted.
  llvm::SmallSetVector<Decl *, 4> DeclsToCheckForDeferredDiags;

public:
// Emit all deferred diagnostics.
void emitDeferredDiags();

enum TUFragmentKind {
  /// The global module fragment, between 'module;' and a module-declaration.
  Global,
  /// A normal translation unit fragment. For a non-module unit, this is the
  /// entire translation unit. Otherwise, it runs from the module-declaration
  /// to the private-module-fragment (if any) or the end of the TU (if not).
  Normal,
  /// The private module fragment, between 'module :private;' and the end of
  /// the translation unit.
  Private
};

void ActOnStartOfTranslationUnit();
void ActOnEndOfTranslationUnit();
void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);

void CheckDelegatingCtorCycles();

Scope *getScopeForContext(DeclContext *Ctx);

void PushFunctionScope();
void PushBlockScope(Scope *BlockScope, BlockDecl *Block);
sema::LambdaScopeInfo *PushLambdaScope();

/// This is used to inform Sema what the current TemplateParameterDepth
/// is during Parsing.  Currently it is used to pass on the depth
/// when parsing generic lambda 'auto' parameters.
void RecordParsingTemplateParameterDepth(unsigned Depth);

void PushCapturedRegionScope(Scope *RegionScope, CapturedDecl *CD,
                             RecordDecl *RD, CapturedRegionKind K,
                             unsigned OpenMPCaptureLevel = 0);

/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
/// time after they've been popped.
class PoppedFunctionScopeDeleter {
  Sema *Self;

public:
  explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
  void operator()(sema::FunctionScopeInfo *Scope) const;
};

using PoppedFunctionScopePtr =
    std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;

PoppedFunctionScopePtr
PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP = nullptr,
                     const Decl *D = nullptr,
                     QualType BlockType = QualType());

sema::FunctionScopeInfo *getCurFunction() const {
  return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
}

sema::FunctionScopeInfo *getEnclosingFunction() const;

void setFunctionHasBranchIntoScope();
void setFunctionHasBranchProtectedScope();
void setFunctionHasIndirectGoto();
void setFunctionHasMustTail();

void PushCompoundScope(bool IsStmtExpr);
void PopCompoundScope();

sema::CompoundScopeInfo &getCurCompoundScope() const;

bool hasAnyUnrecoverableErrorsInThisFunction() const;

/// Retrieve the current block, if any.
sema::BlockScopeInfo *getCurBlock();

/// Get the innermost lambda enclosing the current location, if any. This
/// looks through intervening non-lambda scopes such as local functions and
/// blocks.
sema::LambdaScopeInfo *getEnclosingLambda() const;

/// Retrieve the current lambda scope info, if any.
/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
/// lambda scope info ignoring all inner capturing scopes that are not
/// lambda scopes.
sema::LambdaScopeInfo *
getCurLambda(bool IgnoreNonLambdaCapturingScope = false);

/// Retrieve the current generic lambda info, if any.
sema::LambdaScopeInfo *getCurGenericLambda();

/// Retrieve the current captured region, if any.
sema::CapturedRegionScopeInfo *getCurCapturedRegion();

/// Retrieve the current function, if any, that should be analyzed for
/// potential availability violations.
sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();

/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
SmallVectorImpl<Decl *> &WeakTopLevelDecls() { return WeakTopLevelDecl; }

/// Called before parsing a function declarator belonging to a function
/// declaration.
void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
                                             unsigned TemplateParameterDepth);

/// Called after parsing a function declarator belonging to a function
/// declaration.
void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);

void ActOnComment(SourceRange Comment);

//===--------------------------------------------------------------------===//
// Type Analysis / Processing: SemaType.cpp.
//

QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
                            const DeclSpec *DS = nullptr);
QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
                            const DeclSpec *DS = nullptr);
QualType BuildPointerType(QualType T,
                          SourceLocation Loc, DeclarationName Entity);
QualType BuildReferenceType(QualType T, bool LValueRef,
                            SourceLocation Loc, DeclarationName Entity);
QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                        Expr *ArraySize, unsigned Quals,
                        SourceRange Brackets, DeclarationName Entity);
QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                            SourceLocation AttrLoc);
QualType BuildMatrixType(QualType T, Expr *NumRows, Expr *NumColumns,
                         SourceLocation AttrLoc);

QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
                               SourceLocation AttrLoc);

/// Same as above, but constructs the AddressSpace index if not provided.
QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
                               SourceLocation AttrLoc);

bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);

bool CheckFunctionReturnType(QualType T, SourceLocation Loc);

/// Build a function type.
///
/// This routine checks the function type according to C++ rules and
/// under the assumption that the result type and parameter types have
/// just been instantiated from a template. It therefore duplicates
/// some of the behavior of GetTypeForDeclarator, but in a much
/// simpler form that is only suitable for this narrow use case.
///
/// \param T The return type of the function.
///
/// \param ParamTypes The parameter types of the function. This array
/// will be modified to account for adjustments to the types of the
/// function parameters.
///
/// \param Loc The location of the entity whose type involves this
/// function type or, if there is no such entity, the location of the
/// type that will have function type.
///
/// \param Entity The name of the entity that involves the function
/// type, if known.
///
/// \param EPI Extra information about the function type. Usually this will
/// be taken from an existing function with the same prototype.
///
/// \returns A suitable function type, if there are no errors. The
/// unqualified type will always be a FunctionProtoType.
/// Otherwise, returns a NULL type.
QualType BuildFunctionType(QualType T,
                           MutableArrayRef<QualType> ParamTypes,
                           SourceLocation Loc, DeclarationName Entity,
                           const FunctionProtoType::ExtProtoInfo &EPI);

QualType BuildMemberPointerType(QualType T, QualType Class,
                                SourceLocation Loc,
                                DeclarationName Entity);
QualType BuildBlockPointerType(QualType T,
                               SourceLocation Loc, DeclarationName Entity);
QualType BuildParenType(QualType T);
QualType BuildAtomicType(QualType T, SourceLocation Loc);
QualType BuildReadPipeType(QualType T,
                       SourceLocation Loc);
QualType BuildWritePipeType(QualType T,
                       SourceLocation Loc);
QualType BuildExtIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);

TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);

/// Package the given type and TSI into a ParsedType.
ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
DeclarationNameInfo GetNameForDeclarator(Declarator &D);
DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
static QualType GetTypeFromParser(ParsedType Ty,
                                  TypeSourceInfo **TInfo = nullptr);
CanThrowResult canThrow(const Stmt *E);
/// Determine whether the callee of a particular function call can throw.
/// E, D and Loc are all optional.
static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D,
                                     SourceLocation Loc = SourceLocation());
const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
                                              const FunctionProtoType *FPT);
void UpdateExceptionSpec(FunctionDecl *FD,
                         const FunctionProtoType::ExceptionSpecInfo &ESI);
bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
bool CheckDistantExceptionSpec(QualType T);
bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New);
bool CheckEquivalentExceptionSpec(
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool CheckEquivalentExceptionSpec(
    const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
                              const PartialDiagnostic &NestedDiagID,
                              const PartialDiagnostic &NoteID,
                              const PartialDiagnostic &NoThrowDiagID,
                              const FunctionProtoType *Superset,
                              SourceLocation SuperLoc,
                              const FunctionProtoType *Subset,
                              SourceLocation SubLoc);
bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID,
                             const PartialDiagnostic &NoteID,
                             const FunctionProtoType *Target,
                             SourceLocation TargetLoc,
                             const FunctionProtoType *Source,
                             SourceLocation SourceLoc);

TypeResult ActOnTypeName(Scope *S, Declarator &D);

/// The parser has parsed the context-sensitive type 'instancetype'
/// in an Objective-C message declaration. Return the appropriate type.
ParsedType ActOnObjCInstanceType(SourceLocation Loc);

/// Abstract class used to diagnose incomplete types.
struct TypeDiagnoser {
  TypeDiagnoser() {}

  virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = 0;
  virtual ~TypeDiagnoser() {}
};

static int getPrintable(int I) { return I; }
static unsigned getPrintable(unsigned I) { return I; }
static bool getPrintable(bool B) { return B; }
static const char * getPrintable(const char *S) { return S; }
static StringRef getPrintable(StringRef S) { return S; }
static const std::string &getPrintable(const std::string &S) { return S; }
static const IdentifierInfo *getPrintable(const IdentifierInfo *II) {
  return II;
}
static DeclarationName getPrintable(DeclarationName N) { return N; }
static QualType getPrintable(QualType T) { return T; }
static SourceRange getPrintable(SourceRange R) { return R; }
static SourceRange getPrintable(SourceLocation L) { return L; }
static SourceRange getPrintable(const Expr *E) { return E->getSourceRange(); }
static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange();}

template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
protected:
  unsigned DiagID;
  std::tuple<const Ts &...> Args;

  template <std::size_t... Is>
  void emit(const SemaDiagnosticBuilder &DB,
            std::index_sequence<Is...>) const {
    // Apply all tuple elements to the builder in order.
    bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
    (void)Dummy;
  }

public:
  BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
      : TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
    assert(DiagID != 0 && "no diagnostic for type diagnoser")((void)0);
  }

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
    emit(DB, std::index_sequence_for<Ts...>());
    DB << T;
  }
};

/// Do a check to make sure \p Name looks like a legal argument for the
/// swift_name attribute applied to decl \p D.  Raise a diagnostic if the name
/// is invalid for the given declaration.
///
/// \p AL is used to provide caret diagnostics in case of a malformed name.
///
/// \returns true if the name is a valid swift name for \p D, false otherwise.
bool DiagnoseSwiftName(Decl *D, StringRef Name, SourceLocation Loc,
                       const ParsedAttr &AL, bool IsAsync);

/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
/// For example, a diagnostic with no other parameters would generally have
/// the form "...%select{incomplete|sizeless}0 type %1...".
template <typename... Ts>
class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
public:
  SizelessTypeDiagnoser(unsigned DiagID, const Ts &... Args)
      : BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
    this->emit(DB, std::index_sequence_for<Ts...>());
    DB << T->isSizelessType() << T;
  }
};

enum class CompleteTypeKind {
  /// Apply the normal rules for complete types.  In particular,
  /// treat all sizeless types as incomplete.
  Normal,

  /// Relax the normal rules for complete types so that they include
  /// sizeless built-in types.
  AcceptSizeless,

  // FIXME: Eventually we should flip the default to Normal and opt in
  // to AcceptSizeless rather than opt out of it.
  Default = AcceptSizeless
};

2153private:
/// Methods for marking which expressions involve dereferencing a pointer
/// marked with the 'noderef' attribute. Expressions are checked bottom up as
/// they are parsed, meaning that a noderef pointer may not be accessed. For
/// example, in `&*p` where `p` is a noderef pointer, we will first parse the
/// `*p`, but need to check that `address of` is called on it. This requires
/// keeping a container of all pending expressions and checking if the address
/// of them are eventually taken.
void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
void CheckAddressOfNoDeref(const Expr *E);
void CheckMemberAccessOfNoDeref(const MemberExpr *E);

bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
                             CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);

struct ModuleScope {
  SourceLocation BeginLoc;
  clang::Module *Module = nullptr;
  bool ModuleInterface = false;
  bool ImplicitGlobalModuleFragment = false;
  VisibleModuleSet OuterVisibleModules;
};
/// The modules we're currently parsing.
llvm::SmallVector<ModuleScope, 16> ModuleScopes;

/// Namespace definitions that we will export when they finish.
llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;

/// Get the module whose scope we are currently within.
Module *getCurrentModule() const {
  return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
}

VisibleModuleSet VisibleModules;

2188public:
/// Get the module owning an entity.
Module *getOwningModule(const Decl *Entity) {
  return Entity->getOwningModule();
}

/// Make a merged definition of an existing hidden definition \p ND
/// visible at the specified location.
void makeMergedDefinitionVisible(NamedDecl *ND);

bool isModuleVisible(const Module *M, bool ModulePrivate = false);

// When loading a non-modular PCH files, this is used to restore module
// visibility.
void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
  VisibleModules.setVisible(Mod, ImportLoc);
}

/// Determine whether a declaration is visible to name lookup.
bool isVisible(const NamedDecl *D) {
  return D->isUnconditionallyVisible() || isVisibleSlow(D);
}

/// Determine whether any declaration of an entity is visible.
bool
hasVisibleDeclaration(const NamedDecl *D,
                      llvm::SmallVectorImpl<Module *> *Modules = nullptr) {
  return isVisible(D) || hasVisibleDeclarationSlow(D, Modules);
}
bool hasVisibleDeclarationSlow(const NamedDecl *D,
                               llvm::SmallVectorImpl<Module *> *Modules);

bool hasVisibleMergedDefinition(NamedDecl *Def);
bool hasMergedDefinitionInCurrentModule(NamedDecl *Def);

/// Determine if \p D and \p Suggested have a structurally compatible
/// layout as described in C11 6.2.7/1.
bool hasStructuralCompatLayout(Decl *D, Decl *Suggested);

/// Determine if \p D has a visible definition. If not, suggest a declaration
/// that should be made visible to expose the definition.
bool hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
                          bool OnlyNeedComplete = false);
bool hasVisibleDefinition(const NamedDecl *D) {
  NamedDecl *Hidden;
  return hasVisibleDefinition(const_cast<NamedDecl*>(D), &Hidden);
}

/// Determine if the template parameter \p D has a visible default argument.
bool
hasVisibleDefaultArgument(const NamedDecl *D,
                          llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is an explicit
/// specialization declaration for a specialization of a template. (For a
/// member specialization, use hasVisibleMemberSpecialization.)
bool hasVisibleExplicitSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is a member
/// specialization declaration (as opposed to an instantiated declaration).
bool hasVisibleMemberSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if \p A and \p B are equivalent internal linkage declarations
/// from different modules, and thus an ambiguity error can be downgraded to
/// an extension warning.
bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
                                            const NamedDecl *B);
void diagnoseEquivalentInternalLinkageDeclarations(
    SourceLocation Loc, const NamedDecl *D,
    ArrayRef<const NamedDecl *> Equiv);

bool isUsualDeallocationFunction(const CXXMethodDecl *FD);

bool isCompleteType(SourceLocation Loc, QualType T,
                    CompleteTypeKind Kind = CompleteTypeKind::Default) {
  return !RequireCompleteTypeImpl(Loc, T, Kind, nullptr);
}
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, unsigned DiagID);

bool RequireCompleteType(SourceLocation Loc, QualType T,
                         TypeDiagnoser &Diagnoser) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, Diagnoser);
}
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, DiagID);
}

template <typename... Ts>
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
                         const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
                              const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
}

/// Get the type of expression E, triggering instantiation to complete the
/// type if necessary -- that is, if the expression refers to a templated
/// static data member of incomplete array type.
///
/// May still return an incomplete type if instantiation was not possible or
/// if the type is incomplete for a different reason. Use
/// RequireCompleteExprType instead if a diagnostic is expected for an
/// incomplete expression type.
QualType getCompletedType(Expr *E);

void completeExprArrayBound(Expr *E);
bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
                             TypeDiagnoser &Diagnoser);
bool RequireCompleteExprType(Expr *E, unsigned DiagID);

template <typename... Ts>
bool RequireCompleteExprType(Expr *E, unsigned DiagID, const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedExprType(Expr *E, unsigned DiagID,
                                  const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
}

bool RequireLiteralType(SourceLocation Loc, QualType T,
                        TypeDiagnoser &Diagnoser);
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);

template <typename... Ts>
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
                        const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireLiteralType(Loc, T, Diagnoser);
}

QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
                           const CXXScopeSpec &SS, QualType T,
                           TagDecl *OwnedTagDecl = nullptr);

QualType getDecltypeForParenthesizedExpr(Expr *E);
QualType BuildTypeofExprType(Expr *E, SourceLocation Loc);
/// If AsUnevaluated is false, E is treated as though it were an evaluated
/// context, such as when building a type for decltype(auto).
QualType BuildDecltypeType(Expr *E, SourceLocation Loc,
                           bool AsUnevaluated = true);
QualType BuildUnaryTransformType(QualType BaseType,
                                 UnaryTransformType::UTTKind UKind,
                                 SourceLocation Loc);

//===--------------------------------------------------------------------===//
// Symbol table / Decl tracking callbacks: SemaDecl.cpp.
//

struct SkipBodyInfo {
  SkipBodyInfo()
      : ShouldSkip(false), CheckSameAsPrevious(false), Previous(nullptr),
        New(nullptr) {}
  bool ShouldSkip;
  bool CheckSameAsPrevious;
  NamedDecl *Previous;
  NamedDecl *New;
};

DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = nullptr);

void DiagnoseUseOfUnimplementedSelectors();

bool isSimpleTypeSpecifier(tok::TokenKind Kind) const;

ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                       Scope *S, CXXScopeSpec *SS = nullptr,
                       bool isClassName = false, bool HasTrailingDot = false,
                       ParsedType ObjectType = nullptr,
                       bool IsCtorOrDtorName = false,
                       bool WantNontrivialTypeSourceInfo = false,
                       bool IsClassTemplateDeductionContext = true,
                       IdentifierInfo **CorrectedII = nullptr);
TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
bool isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S);
void DiagnoseUnknownTypeName(IdentifierInfo *&II,
                             SourceLocation IILoc,
                             Scope *S,
                             CXXScopeSpec *SS,
                             ParsedType &SuggestedType,
                             bool IsTemplateName = false);

/// Attempt to behave like MSVC in situations where lookup of an unqualified
/// type name has failed in a dependent context. In these situations, we
/// automatically form a DependentTypeName that will retry lookup in a related
/// scope during instantiation.
ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
                                    SourceLocation NameLoc,
                                    bool IsTemplateTypeArg);

/// Describes the result of the name lookup and resolution performed
/// by \c ClassifyName().
enum NameClassificationKind {
  /// This name is not a type or template in this context, but might be
  /// something else.
  NC_Unknown,
  /// Classification failed; an error has been produced.
  NC_Error,
  /// The name has been typo-corrected to a keyword.
  NC_Keyword,
  /// The name was classified as a type.
  NC_Type,
  /// The name was classified as a specific non-type, non-template
  /// declaration. ActOnNameClassifiedAsNonType should be called to
  /// convert the declaration to an expression.
  NC_NonType,
  /// The name was classified as an ADL-only function name.
  /// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
  /// result to an expression.
  NC_UndeclaredNonType,
  /// The name denotes a member of a dependent type that could not be
  /// resolved. ActOnNameClassifiedAsDependentNonType should be called to
  /// convert the result to an expression.
  NC_DependentNonType,
  /// The name was classified as an overload set, and an expression
  /// representing that overload set has been formed.
  /// ActOnNameClassifiedAsOverloadSet should be called to form a suitable
  /// expression referencing the overload set.
  NC_OverloadSet,
  /// The name was classified as a template whose specializations are types.
  NC_TypeTemplate,
  /// The name was classified as a variable template name.
  NC_VarTemplate,
  /// The name was classified as a function template name.
  NC_FunctionTemplate,
  /// The name was classified as an ADL-only function template name.
  NC_UndeclaredTemplate,
  /// The name was classified as a concept name.
  NC_Concept,
};

class NameClassification {
  NameClassificationKind Kind;
  union {
    ExprResult Expr;
    NamedDecl *NonTypeDecl;
    TemplateName Template;
    ParsedType Type;
  };

  explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}

public:
  NameClassification(ParsedType Type) : Kind(NC_Type), Type(Type) {}

  NameClassification(const IdentifierInfo *Keyword) : Kind(NC_Keyword) {}

  static NameClassification Error() {
    return NameClassification(NC_Error);
  }

  static NameClassification Unknown() {
    return NameClassification(NC_Unknown);
  }

  static NameClassification OverloadSet(ExprResult E) {
    NameClassification Result(NC_OverloadSet);
    Result.Expr = E;
    return Result;
  }

  static NameClassification NonType(NamedDecl *D) {
    NameClassification Result(NC_NonType);
    Result.NonTypeDecl = D;
    return Result;
  }

  static NameClassification UndeclaredNonType() {
    return NameClassification(NC_UndeclaredNonType);
  }

  static NameClassification DependentNonType() {
    return NameClassification(NC_DependentNonType);
  }

  static NameClassification TypeTemplate(TemplateName Name) {
    NameClassification Result(NC_TypeTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification VarTemplate(TemplateName Name) {
    NameClassification Result(NC_VarTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification FunctionTemplate(TemplateName Name) {
    NameClassification Result(NC_FunctionTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification Concept(TemplateName Name) {
    NameClassification Result(NC_Concept);
    Result.Template = Name;
    return Result;
  }

  static NameClassification UndeclaredTemplate(TemplateName Name) {
    NameClassification Result(NC_UndeclaredTemplate);
    Result.Template = Name;
    return Result;
  }

  NameClassificationKind getKind() const { return Kind; }

  ExprResult getExpression() const {
    assert(Kind == NC_OverloadSet)((void)0);
    return Expr;
  }

  ParsedType getType() const {
    assert(Kind == NC_Type)((void)0);
    return Type;
  }

  NamedDecl *getNonTypeDecl() const {
    assert(Kind == NC_NonType)((void)0);
    return NonTypeDecl;
  }

  TemplateName getTemplateName() const {
    assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate ||((void)0)
           Kind == NC_VarTemplate || Kind == NC_Concept ||((void)0)
           Kind == NC_UndeclaredTemplate)((void)0);
    return Template;
  }

  TemplateNameKind getTemplateNameKind() const {
    switch (Kind) {
    case NC_TypeTemplate:
      return TNK_Type_template;
    case NC_FunctionTemplate:
      return TNK_Function_template;
    case NC_VarTemplate:
      return TNK_Var_template;
    case NC_Concept:
      return TNK_Concept_template;
    case NC_UndeclaredTemplate:
      return TNK_Undeclared_template;
    default:
      llvm_unreachable("unsupported name classification.")__builtin_unreachable();
    }
  }
};

/// Perform name lookup on the given name, classifying it based on
/// the results of name lookup and the following token.
///
/// This routine is used by the parser to resolve identifiers and help direct
/// parsing. When the identifier cannot be found, this routine will attempt
/// to correct the typo and classify based on the resulting name.
///
/// \param S The scope in which we're performing name lookup.
///
/// \param SS The nested-name-specifier that precedes the name.
///
/// \param Name The identifier. If typo correction finds an alternative name,
/// this pointer parameter will be updated accordingly.
///
/// \param NameLoc The location of the identifier.
///
/// \param NextToken The token following the identifier. Used to help
/// disambiguate the name.
///
/// \param CCC The correction callback, if typo correction is desired.
NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
                                IdentifierInfo *&Name, SourceLocation NameLoc,
                                const Token &NextToken,
                                CorrectionCandidateCallback *CCC = nullptr);

/// Act on the result of classifying a name as an undeclared (ADL-only)
/// non-type declaration.
ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
                                                  SourceLocation NameLoc);
/// Act on the result of classifying a name as an undeclared member of a
/// dependent base class.
ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
                                                 IdentifierInfo *Name,
                                                 SourceLocation NameLoc,
                                                 bool IsAddressOfOperand);
/// Act on the result of classifying a name as a specific non-type
/// declaration.
ExprResult ActOnNameClassifiedAsNonType(Scope *S, const CXXScopeSpec &SS,
                                        NamedDecl *Found,
                                        SourceLocation NameLoc,
                                        const Token &NextToken);
/// Act on the result of classifying a name as an overload set.
ExprResult ActOnNameClassifiedAsOverloadSet(Scope *S, Expr *OverloadSet);

/// Describes the detailed kind of a template name. Used in diagnostics.
enum class TemplateNameKindForDiagnostics {
  ClassTemplate,
  FunctionTemplate,
  VarTemplate,
  AliasTemplate,
  TemplateTemplateParam,
  Concept,
  DependentTemplate
};
TemplateNameKindForDiagnostics
getTemplateNameKindForDiagnostics(TemplateName Name);

/// Determine whether it's plausible that E was intended to be a
/// template-name.
bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
  if (!getLangOpts().CPlusPlus || E.isInvalid())
    return false;
  Dependent = false;
  if (auto *DRE = dyn_cast<DeclRefExpr>(E.get()))
    return !DRE->hasExplicitTemplateArgs();
  if (auto *ME = dyn_cast<MemberExpr>(E.get()))
    return !ME->hasExplicitTemplateArgs();
  Dependent = true;
  if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(E.get()))
    return !DSDRE->hasExplicitTemplateArgs();
  if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(E.get()))
    return !DSME->hasExplicitTemplateArgs();
  // Any additional cases recognized here should also be handled by
  // diagnoseExprIntendedAsTemplateName.
  return false;
}
void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
                                        SourceLocation Less,
                                        SourceLocation Greater);

void warnOnReservedIdentifier(const NamedDecl *D);

Decl *ActOnDeclarator(Scope *S, Declarator &D);

NamedDecl *HandleDeclarator(Scope *S, Declarator &D,
                            MultiTemplateParamsArg TemplateParameterLists);
bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo,
                                     QualType &T, SourceLocation Loc,
                                     unsigned FailedFoldDiagID);
void RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S);
bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                  DeclarationName Name, SourceLocation Loc,
                                  bool IsTemplateId);
void
diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                          SourceLocation FallbackLoc,
                          SourceLocation ConstQualLoc = SourceLocation(),
                          SourceLocation VolatileQualLoc = SourceLocation(),
                          SourceLocation RestrictQualLoc = SourceLocation(),
                          SourceLocation AtomicQualLoc = SourceLocation(),
                          SourceLocation UnalignedQualLoc = SourceLocation());

static bool adjustContextForLocalExternDecl(DeclContext *&DC);
void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
NamedDecl *getShadowedDeclaration(const TypedefNameDecl *D,
                                  const LookupResult &R);
NamedDecl *getShadowedDeclaration(const VarDecl *D, const LookupResult &R);
NamedDecl *getShadowedDeclaration(const BindingDecl *D,
                                  const LookupResult &R);
void CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
                 const LookupResult &R);
void CheckShadow(Scope *S, VarDecl *D);

/// Warn if 'E', which is an expression that is about to be modified, refers
/// to a shadowing declaration.
void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);

void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);

2669private:
/// Map of current shadowing declarations to shadowed declarations. Warn if
/// it looks like the user is trying to modify the shadowing declaration.
llvm::DenseMap<const NamedDecl *, const NamedDecl *> ShadowingDecls;

2674public:
void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
void handleTagNumbering(const TagDecl *Tag, Scope *TagScope);
void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
                                  TypedefNameDecl *NewTD);
void CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *D);
NamedDecl* ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                  TypeSourceInfo *TInfo,
                                  LookupResult &Previous);
NamedDecl* ActOnTypedefNameDecl(Scope* S, DeclContext* DC, TypedefNameDecl *D,
                                LookupResult &Previous, bool &Redeclaration);
NamedDecl *ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope,
                                   ArrayRef<BindingDecl *> Bindings = None);
NamedDecl *
ActOnDecompositionDeclarator(Scope *S, Declarator &D,
                             MultiTemplateParamsArg TemplateParamLists);
// Returns true if the variable declaration is a redeclaration
bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
void CheckVariableDeclarationType(VarDecl *NewVD);
bool DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                   Expr *Init);
void CheckCompleteVariableDeclaration(VarDecl *VD);
void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);

NamedDecl* ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope);
bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);

enum class CheckConstexprKind {
  /// Diagnose issues that are non-constant or that are extensions.
  Diagnose,
  /// Identify whether this function satisfies the formal rules for constexpr
  /// functions in the current lanugage mode (with no extensions).
  CheckValid
};

bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
                                      CheckConstexprKind Kind);

void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
void FindHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
void NoteHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
// Returns true if the function declaration is a redeclaration
bool CheckFunctionDeclaration(Scope *S,
                              FunctionDecl *NewFD, LookupResult &Previous,
                              bool IsMemberSpecialization);
bool shouldLinkDependentDeclWithPrevious(Decl *D, Decl *OldDecl);
bool canFullyTypeCheckRedeclaration(ValueDecl *NewD, ValueDecl *OldD,
                                    QualType NewT, QualType OldT);
void CheckMain(FunctionDecl *FD, const DeclSpec &D);
void CheckMSVCRTEntryPoint(FunctionDecl *FD);
Attr *getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD,
                                                 bool IsDefinition);
void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                        SourceLocation Loc,
                                        QualType T);
ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                            SourceLocation NameLoc, IdentifierInfo *Name,
                            QualType T, TypeSourceInfo *TSInfo,
                            StorageClass SC);
void ActOnParamDefaultArgument(Decl *param,
                               SourceLocation EqualLoc,
                               Expr *defarg);
void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
                                       SourceLocation ArgLoc);
void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc);
ExprResult ConvertParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                                       SourceLocation EqualLoc);
void SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                             SourceLocation EqualLoc);

// Contexts where using non-trivial C union types can be disallowed. This is
// passed to err_non_trivial_c_union_in_invalid_context.
enum NonTrivialCUnionContext {
  // Function parameter.
  NTCUC_FunctionParam,
  // Function return.
  NTCUC_FunctionReturn,
  // Default-initialized object.
  NTCUC_DefaultInitializedObject,
  // Variable with automatic storage duration.
  NTCUC_AutoVar,
  // Initializer expression that might copy from another object.
  NTCUC_CopyInit,
  // Assignment.
  NTCUC_Assignment,
  // Compound literal.
  NTCUC_CompoundLiteral,
  // Block capture.
  NTCUC_BlockCapture,
  // lvalue-to-rvalue conversion of volatile type.
  NTCUC_LValueToRValueVolatile,
};

/// Emit diagnostics if the initializer or any of its explicit or
/// implicitly-generated subexpressions require copying or
/// default-initializing a type that is or contains a C union type that is
/// non-trivial to copy or default-initialize.
void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);

// These flags are passed to checkNonTrivialCUnion.
enum NonTrivialCUnionKind {
  NTCUK_Init = 0x1,
  NTCUK_Destruct = 0x2,
  NTCUK_Copy = 0x4,
};

/// Emit diagnostics if a non-trivial C union type or a struct that contains
/// a non-trivial C union is used in an invalid context.
void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
                           NonTrivialCUnionContext UseContext,
                           unsigned NonTrivialKind);

void AddInitializerToDecl(Decl *dcl, Expr *init, bool DirectInit);
void ActOnUninitializedDecl(Decl *dcl);
void ActOnInitializerError(Decl *Dcl);

void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
void ActOnCXXForRangeDecl(Decl *D);
StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
                                      IdentifierInfo *Ident,
                                      ParsedAttributes &Attrs,
                                      SourceLocation AttrEnd);
void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc);
void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
void CheckStaticLocalForDllExport(VarDecl *VD);
void FinalizeDeclaration(Decl *D);
DeclGroupPtrTy FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                       ArrayRef<Decl *> Group);
DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);

/// Should be called on all declarations that might have attached
/// documentation comments.
void ActOnDocumentableDecl(Decl *D);
void ActOnDocumentableDecls(ArrayRef<Decl *> Group);

void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                     SourceLocation LocAfterDecls);
void CheckForFunctionRedefinition(
    FunctionDecl *FD, const FunctionDecl *EffectiveDefinition = nullptr,
    SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D,
                              MultiTemplateParamsArg TemplateParamLists,
                              SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D,
                              SkipBodyInfo *SkipBody = nullptr);
void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);
bool isObjCMethodDecl(Decl *D) {
  return D && isa<ObjCMethodDecl>(D);
}

/// Determine whether we can delay parsing the body of a function or
/// function template until it is used, assuming we don't care about emitting
/// code for that function.
///
/// This will be \c false if we may need the body of the function in the
/// middle of parsing an expression (where it's impractical to switch to
/// parsing a different function), for instance, if it's constexpr in C++11
/// or has an 'auto' return type in C++14. These cases are essentially bugs.
bool canDelayFunctionBody(const Declarator &D);

/// Determine whether we can skip parsing the body of a function
/// definition, assuming we don't care about analyzing its body or emitting
/// code for that function.
///
/// This will be \c false only if we may need the body of the function in
/// order to parse the rest of the program (for instance, if it is
/// \c constexpr in C++11 or has an 'auto' return type in C++14).
bool canSkipFunctionBody(Decl *D);

void computeNRVO(Stmt *Body, sema::FunctionScopeInfo *Scope);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body, bool IsInstantiation);
Decl *ActOnSkippedFunctionBody(Decl *Decl);
void ActOnFinishInlineFunctionDef(FunctionDecl *D);

/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
/// attribute for which parsing is delayed.
void ActOnFinishDelayedAttribute(Scope *S, Decl *D, ParsedAttributes &Attrs);

/// Diagnose any unused parameters in the given sequence of
/// ParmVarDecl pointers.
void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);

/// Diagnose whether the size of parameters or return value of a
/// function or obj-c method definition is pass-by-value and larger than a
/// specified threshold.
void
DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
                                       QualType ReturnTy, NamedDecl *D);

void DiagnoseInvalidJumps(Stmt *Body);
Decl *ActOnFileScopeAsmDecl(Expr *expr,
                            SourceLocation AsmLoc,
                            SourceLocation RParenLoc);

/// Handle a C++11 empty-declaration and attribute-declaration.
Decl *ActOnEmptyDeclaration(Scope *S, const ParsedAttributesView &AttrList,
                            SourceLocation SemiLoc);

enum class ModuleDeclKind {
  Interface,      ///< 'export module X;'
  Implementation, ///< 'module X;'
};

/// The parser has processed a module-declaration that begins the definition
/// of a module interface or implementation.
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
                               SourceLocation ModuleLoc, ModuleDeclKind MDK,
                               ModuleIdPath Path, bool IsFirstDecl);

/// The parser has processed a global-module-fragment declaration that begins
/// the definition of the global module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);

/// The parser has processed a private-module-fragment declaration that begins
/// the definition of the private module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
/// \param PrivateLoc The location of the 'private' keyword.
DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
                                              SourceLocation PrivateLoc);

/// The parser has processed a module import declaration.
///
/// \param StartLoc The location of the first token in the declaration. This
///        could be the location of an '@', 'export', or 'import'.
/// \param ExportLoc The location of the 'export' keyword, if any.
/// \param ImportLoc The location of the 'import' keyword.
/// \param Path The module access path.
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, ModuleIdPath Path);
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, Module *M,
                             ModuleIdPath Path = {});

/// The parser has processed a module import translated from a
/// #include or similar preprocessing directive.
void ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);

/// The parsed has entered a submodule.
void ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
/// The parser has left a submodule.
void ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod);

/// Create an implicit import of the given module at the given
/// source location, for error recovery, if possible.
///
/// This routine is typically used when an entity found by name lookup
/// is actually hidden within a module that we know about but the user
/// has forgotten to import.
void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
                                                Module *Mod);

/// Kinds of missing import. Note, the values of these enumerators correspond
/// to %select values in diagnostics.
enum class MissingImportKind {
  Declaration,
  Definition,
  DefaultArgument,
  ExplicitSpecialization,
  PartialSpecialization
};

/// Diagnose that the specified declaration needs to be visible but
/// isn't, and suggest a module import that would resolve the problem.
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           MissingImportKind MIK, bool Recover = true);
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           SourceLocation DeclLoc, ArrayRef<Module *> Modules,
                           MissingImportKind MIK, bool Recover);

Decl *ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
                           SourceLocation LBraceLoc);
Decl *ActOnFinishExportDecl(Scope *S, Decl *ExportDecl,
                            SourceLocation RBraceLoc);

/// We've found a use of a templated declaration that would trigger an
/// implicit instantiation. Check that any relevant explicit specializations
/// and partial specializations are visible, and diagnose if not.
void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);

/// Retrieve a suitable printing policy for diagnostics.
PrintingPolicy getPrintingPolicy() const {
  return getPrintingPolicy(Context, PP);
}

/// Retrieve a suitable printing policy for diagnostics.
static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
                                        const Preprocessor &PP);

/// Scope actions.
void ActOnPopScope(SourceLocation Loc, Scope *S);
void ActOnTranslationUnitScope(Scope *S);

Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 RecordDecl *&AnonRecord);
Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 MultiTemplateParamsArg TemplateParams,
                                 bool IsExplicitInstantiation,
                                 RecordDecl *&AnonRecord);

Decl *BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                  AccessSpecifier AS,
                                  RecordDecl *Record,
                                  const PrintingPolicy &Policy);

Decl *BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                     RecordDecl *Record);

/// Common ways to introduce type names without a tag for use in diagnostics.
/// Keep in sync with err_tag_reference_non_tag.
enum NonTagKind {
  NTK_NonStruct,
  NTK_NonClass,
  NTK_NonUnion,
  NTK_NonEnum,
  NTK_Typedef,
  NTK_TypeAlias,
  NTK_Template,
  NTK_TypeAliasTemplate,
  NTK_TemplateTemplateArgument,
};

/// Given a non-tag type declaration, returns an enum useful for indicating
/// what kind of non-tag type this is.
NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);

bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                  TagTypeKind NewTag, bool isDefinition,
                                  SourceLocation NewTagLoc,
                                  const IdentifierInfo *Name);

enum TagUseKind {
  TUK_Reference,   // Reference to a tag:  'struct foo *X;'
  TUK_Declaration, // Fwd decl of a tag:   'struct foo;'
  TUK_Definition,  // Definition of a tag: 'struct foo { int X; } Y;'
  TUK_Friend       // Friend declaration:  'friend struct foo;'
};

Decl *ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
               SourceLocation KWLoc, CXXScopeSpec &SS, IdentifierInfo *Name,
               SourceLocation NameLoc, const ParsedAttributesView &Attr,
               AccessSpecifier AS, SourceLocation ModulePrivateLoc,
               MultiTemplateParamsArg TemplateParameterLists, bool &OwnedDecl,
               bool &IsDependent, SourceLocation ScopedEnumKWLoc,
               bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
               bool IsTypeSpecifier, bool IsTemplateParamOrArg,
               SkipBodyInfo *SkipBody = nullptr);

Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                              unsigned TagSpec, SourceLocation TagLoc,
                              CXXScopeSpec &SS, IdentifierInfo *Name,
                              SourceLocation NameLoc,
                              const ParsedAttributesView &Attr,
                              MultiTemplateParamsArg TempParamLists);

TypeResult ActOnDependentTag(Scope *S,
                             unsigned TagSpec,
                             TagUseKind TUK,
                             const CXXScopeSpec &SS,
                             IdentifierInfo *Name,
                             SourceLocation TagLoc,
                             SourceLocation NameLoc);

void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
               IdentifierInfo *ClassName,
               SmallVectorImpl<Decl *> &Decls);
Decl *ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                 Declarator &D, Expr *BitfieldWidth);

FieldDecl *HandleField(Scope *S, RecordDecl *TagD, SourceLocation DeclStart,
                       Declarator &D, Expr *BitfieldWidth,
                       InClassInitStyle InitStyle,
                       AccessSpecifier AS);
MSPropertyDecl *HandleMSProperty(Scope *S, RecordDecl *TagD,
                                 SourceLocation DeclStart, Declarator &D,
                                 Expr *BitfieldWidth,
                                 InClassInitStyle InitStyle,
                                 AccessSpecifier AS,
                                 const ParsedAttr &MSPropertyAttr);

FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
                          TypeSourceInfo *TInfo,
                          RecordDecl *Record, SourceLocation Loc,
                          bool Mutable, Expr *BitfieldWidth,
                          InClassInitStyle InitStyle,
                          SourceLocation TSSL,
                          AccessSpecifier AS, NamedDecl *PrevDecl,
                          Declarator *D = nullptr);

bool CheckNontrivialField(FieldDecl *FD);
void DiagnoseNontrivial(const CXXRecordDecl *Record, CXXSpecialMember CSM);

enum TrivialABIHandling {
  /// The triviality of a method unaffected by "trivial_abi".
  TAH_IgnoreTrivialABI,

  /// The triviality of a method affected by "trivial_abi".
  TAH_ConsiderTrivialABI
};

bool SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
                            TrivialABIHandling TAH = TAH_IgnoreTrivialABI,
                            bool Diagnose = false);

/// For a defaulted function, the kind of defaulted function that it is.
class DefaultedFunctionKind {
  CXXSpecialMember SpecialMember : 8;
  DefaultedComparisonKind Comparison : 8;

public:
  DefaultedFunctionKind()
      : SpecialMember(CXXInvalid), Comparison(DefaultedComparisonKind::None) {
  }
  DefaultedFunctionKind(CXXSpecialMember CSM)
      : SpecialMember(CSM), Comparison(DefaultedComparisonKind::None) {}
  DefaultedFunctionKind(DefaultedComparisonKind Comp)
      : SpecialMember(CXXInvalid), Comparison(Comp) {}

  bool isSpecialMember() const { return SpecialMember != CXXInvalid; }
  bool isComparison() const {
    return Comparison != DefaultedComparisonKind::None;
  }

  explicit operator bool() const {
    return isSpecialMember() || isComparison();
  }

  CXXSpecialMember asSpecialMember() const { return SpecialMember; }
  DefaultedComparisonKind asComparison() const { return Comparison; }

  /// Get the index of this function kind for use in diagnostics.
  unsigned getDiagnosticIndex() const {
    static_assert(CXXInvalid > CXXDestructor,
                  "invalid should have highest index");
    static_assert((unsigned)DefaultedComparisonKind::None == 0,
                  "none should be equal to zero");
    return SpecialMember + (unsigned)Comparison;
  }
};

DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);

CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD) {
  return getDefaultedFunctionKind(MD).asSpecialMember();
}
DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl *FD) {
  return getDefaultedFunctionKind(FD).asComparison();
}

void ActOnLastBitfield(SourceLocation DeclStart,
                       SmallVectorImpl<Decl *> &AllIvarDecls);
Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
                Declarator &D, Expr *BitfieldWidth,
                tok::ObjCKeywordKind visibility);

// This is used for both record definitions and ObjC interface declarations.
void ActOnFields(Scope *S, SourceLocation RecLoc, Decl *TagDecl,
                 ArrayRef<Decl *> Fields, SourceLocation LBrac,
                 SourceLocation RBrac, const ParsedAttributesView &AttrList);

/// ActOnTagStartDefinition - Invoked when we have entered the
/// scope of a tag's definition (e.g., for an enumeration, class,
/// struct, or union).
void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);

/// Perform ODR-like check for C/ObjC when merging tag types from modules.
/// Differently from C++, actually parse the body and reject / error out
/// in case of a structural mismatch.
bool ActOnDuplicateDefinition(DeclSpec &DS, Decl *Prev,
                              SkipBodyInfo &SkipBody);

typedef void *SkippedDefinitionContext;

/// Invoked when we enter a tag definition that we're skipping.
SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope *S, Decl *TD);

Decl *ActOnObjCContainerStartDefinition(Decl *IDecl);

/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
/// C++ record definition's base-specifiers clause and are starting its
/// member declarations.
void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                     SourceLocation FinalLoc,
                                     bool IsFinalSpelledSealed,
                                     bool IsAbstract,
                                     SourceLocation LBraceLoc);

/// ActOnTagFinishDefinition - Invoked once we have finished parsing
/// the definition of a tag (enumeration, class, struct, or union).
void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
                              SourceRange BraceRange);

void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);

void ActOnObjCContainerFinishDefinition();

/// Invoked when we must temporarily exit the objective-c container
/// scope for parsing/looking-up C constructs.
///
/// Must be followed by a call to \see ActOnObjCReenterContainerContext
void ActOnObjCTemporaryExitContainerContext(DeclContext *DC);
void ActOnObjCReenterContainerContext(DeclContext *DC);

/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
/// error parsing the definition of a tag.
void ActOnTagDefinitionError(Scope *S, Decl *TagDecl);

EnumConstantDecl *CheckEnumConstant(EnumDecl *Enum,
                                    EnumConstantDecl *LastEnumConst,
                                    SourceLocation IdLoc,
                                    IdentifierInfo *Id,
                                    Expr *val);
bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                            QualType EnumUnderlyingTy, bool IsFixed,
                            const EnumDecl *Prev);

/// Determine whether the body of an anonymous enumeration should be skipped.
/// \param II The name of the first enumerator.
SkipBodyInfo shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                    SourceLocation IILoc);

Decl *ActOnEnumConstant(Scope *S, Decl *EnumDecl, Decl *LastEnumConstant,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        const ParsedAttributesView &Attrs,
                        SourceLocation EqualLoc, Expr *Val);
void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
                   Decl *EnumDecl, ArrayRef<Decl *> Elements, Scope *S,
                   const ParsedAttributesView &Attr);

/// Set the current declaration context until it gets popped.
void PushDeclContext(Scope *S, DeclContext *DC);
void PopDeclContext();

/// EnterDeclaratorContext - Used when we must lookup names in the context
/// of a declarator's nested name specifier.
void EnterDeclaratorContext(Scope *S, DeclContext *DC);
void ExitDeclaratorContext(Scope *S);

/// Enter a template parameter scope, after it's been associated with a particular
/// DeclContext. Causes lookup within the scope to chain through enclosing contexts
/// in the correct order.
void EnterTemplatedContext(Scope *S, DeclContext *DC);

/// Push the parameters of D, which must be a function, into scope.
void ActOnReenterFunctionContext(Scope* S, Decl* D);
void ActOnExitFunctionContext();

DeclContext *getFunctionLevelDeclContext();

/// getCurFunctionDecl - If inside of a function body, this returns a pointer
/// to the function decl for the function being parsed.  If we're currently
/// in a 'block', this returns the containing context.
FunctionDecl *getCurFunctionDecl();

/// getCurMethodDecl - If inside of a method body, this returns a pointer to
/// the method decl for the method being parsed.  If we're currently
/// in a 'block', this returns the containing context.
ObjCMethodDecl *getCurMethodDecl();

/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
/// or C function we're in, otherwise return null.  If we're currently
/// in a 'block', this returns the containing context.
NamedDecl *getCurFunctionOrMethodDecl();

/// Add this decl to the scope shadowed decl chains.
void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);

/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
/// true if 'D' belongs to the given declaration context.
///
/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
///        enclosing namespace set of the context, rather than contained
///        directly within it.
bool isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S = nullptr,
                   bool AllowInlineNamespace = false);

/// Finds the scope corresponding to the given decl context, if it
/// happens to be an enclosing scope.  Otherwise return NULL.
static Scope *getScopeForDeclContext(Scope *S, DeclContext *DC);

/// Subroutines of ActOnDeclarator().
TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                              TypeSourceInfo *TInfo);
bool isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New);

/// Describes the kind of merge to perform for availability
/// attributes (including "deprecated", "unavailable", and "availability").
enum AvailabilityMergeKind {
  /// Don't merge availability attributes at all.
  AMK_None,
  /// Merge availability attributes for a redeclaration, which requires
  /// an exact match.
  AMK_Redeclaration,
  /// Merge availability attributes for an override, which requires
  /// an exact match or a weakening of constraints.
  AMK_Override,
  /// Merge availability attributes for an implementation of
  /// a protocol requirement.
  AMK_ProtocolImplementation,
  /// Merge availability attributes for an implementation of
  /// an optional protocol requirement.
  AMK_OptionalProtocolImplementation
};

/// Describes the kind of priority given to an availability attribute.
///
/// The sum of priorities deteremines the final priority of the attribute.
/// The final priority determines how the attribute will be merged.
/// An attribute with a lower priority will always remove higher priority
/// attributes for the specified platform when it is being applied. An
/// attribute with a higher priority will not be applied if the declaration
/// already has an availability attribute with a lower priority for the
/// specified platform. The final prirority values are not expected to match
/// the values in this enumeration, but instead should be treated as a plain
/// integer value. This enumeration just names the priority weights that are
/// used to calculate that final vaue.
enum AvailabilityPriority : int {
  /// The availability attribute was specified explicitly next to the
  /// declaration.
  AP_Explicit = 0,

  /// The availability attribute was applied using '#pragma clang attribute'.
  AP_PragmaClangAttribute = 1,

  /// The availability attribute for a specific platform was inferred from
  /// an availability attribute for another platform.
  AP_InferredFromOtherPlatform = 2
};

/// Attribute merging methods. Return true if a new attribute was added.
AvailabilityAttr *
mergeAvailabilityAttr(NamedDecl *D, const AttributeCommonInfo &CI,
                      IdentifierInfo *Platform, bool Implicit,
                      VersionTuple Introduced, VersionTuple Deprecated,
                      VersionTuple Obsoleted, bool IsUnavailable,
                      StringRef Message, bool IsStrict, StringRef Replacement,
                      AvailabilityMergeKind AMK, int Priority);
TypeVisibilityAttr *
mergeTypeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                        TypeVisibilityAttr::VisibilityType Vis);
VisibilityAttr *mergeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                                    VisibilityAttr::VisibilityType Vis);
UuidAttr *mergeUuidAttr(Decl *D, const AttributeCommonInfo &CI,
                        StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
DLLImportAttr *mergeDLLImportAttr(Decl *D, const AttributeCommonInfo &CI);
DLLExportAttr *mergeDLLExportAttr(Decl *D, const AttributeCommonInfo &CI);
MSInheritanceAttr *mergeMSInheritanceAttr(Decl *D,
                                          const AttributeCommonInfo &CI,
                                          bool BestCase,
                                          MSInheritanceModel Model);
FormatAttr *mergeFormatAttr(Decl *D, const AttributeCommonInfo &CI,
                            IdentifierInfo *Format, int FormatIdx,
                            int FirstArg);
SectionAttr *mergeSectionAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
CodeSegAttr *mergeCodeSegAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
AlwaysInlineAttr *mergeAlwaysInlineAttr(Decl *D,
                                        const AttributeCommonInfo &CI,
                                        const IdentifierInfo *Ident);
MinSizeAttr *mergeMinSizeAttr(Decl *D, const AttributeCommonInfo &CI);
SwiftNameAttr *mergeSwiftNameAttr(Decl *D, const SwiftNameAttr &SNA,
                                  StringRef Name);
OptimizeNoneAttr *mergeOptimizeNoneAttr(Decl *D,
                                        const AttributeCommonInfo &CI);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D, const ParsedAttr &AL);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D,
                                              const InternalLinkageAttr &AL);
WebAssemblyImportNameAttr *mergeImportNameAttr(
    Decl *D, const WebAssemblyImportNameAttr &AL);
WebAssemblyImportModuleAttr *mergeImportModuleAttr(
    Decl *D, const WebAssemblyImportModuleAttr &AL);
EnforceTCBAttr *mergeEnforceTCBAttr(Decl *D, const EnforceTCBAttr &AL);
EnforceTCBLeafAttr *mergeEnforceTCBLeafAttr(Decl *D,
                                            const EnforceTCBLeafAttr &AL);

void mergeDeclAttributes(NamedDecl *New, Decl *Old,
                         AvailabilityMergeKind AMK = AMK_Redeclaration);
void MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
                          LookupResult &OldDecls);
bool MergeFunctionDecl(FunctionDecl *New, NamedDecl *&Old, Scope *S,
                       bool MergeTypeWithOld);
bool MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                  Scope *S, bool MergeTypeWithOld);
void mergeObjCMethodDecls(ObjCMethodDecl *New, ObjCMethodDecl *Old);
void MergeVarDecl(VarDecl *New, LookupResult &Previous);
void MergeVarDeclTypes(VarDecl *New, VarDecl *Old, bool MergeTypeWithOld);
void MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old);
bool checkVarDeclRedefinition(VarDecl *OldDefn, VarDecl *NewDefn);
void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
bool MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old, Scope *S);

// AssignmentAction - This is used by all the assignment diagnostic functions
// to represent what is actually causing the operation
enum AssignmentAction {
  AA_Assigning,
  AA_Passing,
  AA_Returning,
  AA_Converting,
  AA_Initializing,
  AA_Sending,
  AA_Casting,
  AA_Passing_CFAudited
};

/// C++ Overloading.
enum OverloadKind {
  /// This is a legitimate overload: the existing declarations are
  /// functions or function templates with different signatures.
  Ovl_Overload,

  /// This is not an overload because the signature exactly matches
  /// an existing declaration.
  Ovl_Match,

  /// This is not an overload because the lookup results contain a
  /// non-function.
  Ovl_NonFunction
};
OverloadKind CheckOverload(Scope *S,
                           FunctionDecl *New,
                           const LookupResult &OldDecls,
                           NamedDecl *&OldDecl,
                           bool IsForUsingDecl);
bool IsOverload(FunctionDecl *New, FunctionDecl *Old, bool IsForUsingDecl,
                bool ConsiderCudaAttrs = true,
                bool ConsiderRequiresClauses = true);

enum class AllowedExplicit {
  /// Allow no explicit functions to be used.
  None,
  /// Allow explicit conversion functions but not explicit constructors.
  Conversions,
  /// Allow both explicit conversion functions and explicit constructors.
  All
};

ImplicitConversionSequence
TryImplicitConversion(Expr *From, QualType ToType,
                      bool SuppressUserConversions,
                      AllowedExplicit AllowExplicit,
                      bool InOverloadResolution,
                      bool CStyle,
                      bool AllowObjCWritebackConversion);

bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
bool IsComplexPromotion(QualType FromType, QualType ToType);
bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                         bool InOverloadResolution,
                         QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCPointerConversion(QualType FromType, QualType ToType,
                             QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCWritebackConversion(QualType FromType, QualType ToType,
                               QualType &ConvertedType);
bool IsBlockPointerConversion(QualType FromType, QualType ToType,
                              QualType& ConvertedType);
bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
                                const FunctionProtoType *NewType,
                                unsigned *ArgPos = nullptr);
void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                QualType FromType, QualType ToType);

void maybeExtendBlockObject(ExprResult &E);
CastKind PrepareCastToObjCObjectPointer(ExprResult &E);
bool CheckPointerConversion(Expr *From, QualType ToType,
                            CastKind &Kind,
                            CXXCastPath& BasePath,
                            bool IgnoreBaseAccess,
                            bool Diagnose = true);
bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
                               bool InOverloadResolution,
                               QualType &ConvertedType);
bool CheckMemberPointerConversion(Expr *From, QualType ToType,
                                  CastKind &Kind,
                                  CXXCastPath &BasePath,
                                  bool IgnoreBaseAccess);
bool IsQualificationConversion(QualType FromType, QualType ToType,
                               bool CStyle, bool &ObjCLifetimeConversion);
bool IsFunctionConversion(QualType FromType, QualType ToType,
                          QualType &ResultTy);
bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
bool isSameOrCompatibleFunctionType(CanQualType Param, CanQualType Arg);

bool CanPerformAggregateInitializationForOverloadResolution(
    const InitializedEntity &Entity, InitListExpr *From);

bool IsStringInit(Expr *Init, const ArrayType *AT);

bool CanPerformCopyInitialization(const InitializedEntity &Entity,
                                  ExprResult Init);
ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
                                     SourceLocation EqualLoc,
                                     ExprResult Init,
                                     bool TopLevelOfInitList = false,
                                     bool AllowExplicit = false);
ExprResult PerformObjectArgumentInitialization(Expr *From,
                                               NestedNameSpecifier *Qualifier,
                                               NamedDecl *FoundDecl,
                                               CXXMethodDecl *Method);

/// Check that the lifetime of the initializer (and its subobjects) is
/// sufficient for initializing the entity, and perform lifetime extension
/// (when permitted) if not.
void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);

ExprResult PerformContextuallyConvertToBool(Expr *From);
ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);

/// Contexts in which a converted constant expression is required.
enum CCEKind {
  CCEK_CaseValue,   ///< Expression in a case label.
  CCEK_Enumerator,  ///< Enumerator value with fixed underlying type.
  CCEK_TemplateArg, ///< Value of a non-type template parameter.
  CCEK_ArrayBound,  ///< Array bound in array declarator or new-expression.
  CCEK_ExplicitBool ///< Condition in an explicit(bool) specifier.
};
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            llvm::APSInt &Value, CCEKind CCE);
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            APValue &Value, CCEKind CCE,
                                            NamedDecl *Dest = nullptr);

/// Abstract base class used to perform a contextual implicit
/// conversion from an expression to any type passing a filter.
class ContextualImplicitConverter {
public:
  bool Suppress;
  bool SuppressConversion;

  ContextualImplicitConverter(bool Suppress = false,
                              bool SuppressConversion = false)
      : Suppress(Suppress), SuppressConversion(SuppressConversion) {}

  /// Determine whether the specified type is a valid destination type
  /// for this conversion.
  virtual bool match(QualType T) = 0;

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the expression has incomplete class type.
  virtual SemaDiagnosticBuilder
  diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the only matching conversion function
  /// is explicit.
  virtual SemaDiagnosticBuilder diagnoseExplicitConv(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  /// Emits a note for the explicit conversion function.
  virtual SemaDiagnosticBuilder
  noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when there are multiple possible conversion
  /// functions.
  virtual SemaDiagnosticBuilder
  diagnoseAmbiguous(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a note for one of the candidate conversions.
  virtual SemaDiagnosticBuilder
  noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when we picked a conversion function
  /// (for cases when we are not allowed to pick a conversion function).
  virtual SemaDiagnosticBuilder diagnoseConversion(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  virtual ~ContextualImplicitConverter() {}
};

class ICEConvertDiagnoser : public ContextualImplicitConverter {
  bool AllowScopedEnumerations;

public:
  ICEConvertDiagnoser(bool AllowScopedEnumerations,
                      bool Suppress, bool SuppressConversion)
      : ContextualImplicitConverter(Suppress, SuppressConversion),
        AllowScopedEnumerations(AllowScopedEnumerations) {}

  /// Match an integral or (possibly scoped) enumeration type.
  bool match(QualType T) override;

  SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) override {
    return diagnoseNotInt(S, Loc, T);
  }

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNotInt(Sema &S, SourceLocation Loc, QualType T) = 0;
};

/// Perform a contextual implicit conversion.
ExprResult PerformContextualImplicitConversion(
    SourceLocation Loc, Expr *FromE, ContextualImplicitConverter &Converter);


enum ObjCSubscriptKind {
  OS_Array,
  OS_Dictionary,
  OS_Error
};
ObjCSubscriptKind CheckSubscriptingKind(Expr *FromE);

// Note that LK_String is intentionally after the other literals, as
// this is used for diagnostics logic.
enum ObjCLiteralKind {
  LK_Array,
  LK_Dictionary,
  LK_Numeric,
  LK_Boxed,
  LK_String,
  LK_Block,
  LK_None
};
ObjCLiteralKind CheckLiteralKind(Expr *FromE);

ExprResult PerformObjectMemberConversion(Expr *From,
                                         NestedNameSpecifier *Qualifier,
                                         NamedDecl *FoundDecl,
                                         NamedDecl *Member);

// Members have to be NamespaceDecl* or TranslationUnitDecl*.
// TODO: make this is a typesafe union.
typedef llvm::SmallSetVector<DeclContext   *, 16> AssociatedNamespaceSet;
typedef llvm::SmallSetVector<CXXRecordDecl *, 16> AssociatedClassSet;

using ADLCallKind = CallExpr::ADLCallKind;

void AddOverloadCandidate(FunctionDecl *Function, DeclAccessPair FoundDecl,
                          ArrayRef<Expr *> Args,
                          OverloadCandidateSet &CandidateSet,
                          bool SuppressUserConversions = false,
                          bool PartialOverloading = false,
                          bool AllowExplicit = true,
                          bool AllowExplicitConversion = false,
                          ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
                          ConversionSequenceList EarlyConversions = None,
                          OverloadCandidateParamOrder PO = {});
void AddFunctionCandidates(const UnresolvedSetImpl &Functions,
                    ArrayRef<Expr *> Args,
                    OverloadCandidateSet &CandidateSet,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    bool SuppressUserConversions = false,
                    bool PartialOverloading = false,
                    bool FirstArgumentIsBase = false);
void AddMethodCandidate(DeclAccessPair FoundDecl,
                        QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversion = false,
                        OverloadCandidateParamOrder PO = {});
void AddMethodCandidate(CXXMethodDecl *Method,
                        DeclAccessPair FoundDecl,
                        CXXRecordDecl *ActingContext, QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversions = false,
                        bool PartialOverloading = false,
                        ConversionSequenceList EarlyConversions = None,
                        OverloadCandidateParamOrder PO = {});
void AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                DeclAccessPair FoundDecl,
                                CXXRecordDecl *ActingContext,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                                QualType ObjectType,
                                Expr::Classification ObjectClassification,
                                ArrayRef<Expr *> Args,
                                OverloadCandidateSet& CandidateSet,
                                bool SuppressUserConversions = false,
                                bool PartialOverloading = false,
                                OverloadCandidateParamOrder PO = {});
void AddTemplateOverloadCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
    bool PartialOverloading = false, bool AllowExplicit = true,
    ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
    OverloadCandidateParamOrder PO = {});
bool CheckNonDependentConversions(
    FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
    ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
    ConversionSequenceList &Conversions, bool SuppressUserConversions,
    CXXRecordDecl *ActingContext = nullptr, QualType ObjectType = QualType(),
    Expr::Classification ObjectClassification = {},
    OverloadCandidateParamOrder PO = {});
void AddConversionCandidate(
    CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddTemplateConversionCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddSurrogateCandidate(CXXConversionDecl *Conversion,
                           DeclAccessPair FoundDecl,
                           CXXRecordDecl *ActingContext,
                           const FunctionProtoType *Proto,
                           Expr *Object, ArrayRef<Expr *> Args,
                           OverloadCandidateSet& CandidateSet);
void AddNonMemberOperatorCandidates(
    const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
    OverloadCandidateSet &CandidateSet,
    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr);
void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
                                 SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                 OverloadCandidateSet &CandidateSet,
                                 OverloadCandidateParamOrder PO = {});
void AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
                         OverloadCandidateSet& CandidateSet,
                         bool IsAssignmentOperator = false,
                         unsigned NumContextualBoolArguments = 0);
void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
                                  SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                  OverloadCandidateSet& CandidateSet);
void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                          SourceLocation Loc,
                                          ArrayRef<Expr *> Args,
                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                                          OverloadCandidateSet& CandidateSet,
                                          bool PartialOverloading = false);

// Emit as a 'note' the specific overload candidate
void NoteOverloadCandidate(
    NamedDecl *Found, FunctionDecl *Fn,
    OverloadCandidateRewriteKind RewriteKind = OverloadCandidateRewriteKind(),
    QualType DestType = QualType(), bool TakingAddress = false);

// Emit as a series of 'note's all template and non-templates identified by
// the expression Expr
void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType(),
                               bool TakingAddress = false);

/// Check the enable_if expressions on the given function. Returns the first
/// failing attribute, or NULL if they were all successful.
EnableIfAttr *CheckEnableIf(FunctionDecl *Function, SourceLocation CallLoc,
                            ArrayRef<Expr *> Args,
                            bool MissingImplicitThis = false);

/// Find the failed Boolean condition within a given Boolean
/// constant expression, and describe it with a string.
std::pair<Expr *, std::string> findFailedBooleanCondition(Expr *Cond);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// non-ArgDependent DiagnoseIfAttrs.
///
/// Argument-dependent diagnose_if attributes should be checked each time a
/// function is used as a direct callee of a function call.
///
/// Returns true if any errors were emitted.
bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
                                         const Expr *ThisArg,
                                         ArrayRef<const Expr *> Args,
                                         SourceLocation Loc);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// ArgDependent DiagnoseIfAttrs.
///
/// Argument-independent diagnose_if attributes should be checked on every use
/// of a function.
///
/// Returns true if any errors were emitted.
bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
                                           SourceLocation Loc);

/// Returns whether the given function's address can be taken or not,
/// optionally emitting a diagnostic if the address can't be taken.
///
/// Returns false if taking the address of the function is illegal.
bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
                                       bool Complain = false,
                                       SourceLocation Loc = SourceLocation());

// [PossiblyAFunctionType]  -->   [Return]
// NonFunctionType --> NonFunctionType
// R (A) --> R(A)
// R (*)(A) --> R (A)
// R (&)(A) --> R (A)
// R (S::*)(A) --> R (A)
QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);

FunctionDecl *
ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                   QualType TargetType,
                                   bool Complain,
                                   DeclAccessPair &Found,
                                   bool *pHadMultipleCandidates = nullptr);

FunctionDecl *
resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &FoundResult);

bool resolveAndFixAddressOfSingleOverloadCandidate(
    ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);

FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
                                            bool Complain = false,
                                            DeclAccessPair *Found = nullptr);

bool ResolveAndFixSingleFunctionTemplateSpecialization(
                    ExprResult &SrcExpr,
                    bool DoFunctionPointerConverion = false,
                    bool Complain = false,
                    SourceRange OpRangeForComplaining = SourceRange(),
                    QualType DestTypeForComplaining = QualType(),
                    unsigned DiagIDForComplaining = 0);


Expr *FixOverloadedFunctionReference(Expr *E,
                                     DeclAccessPair FoundDecl,
                                     FunctionDecl *Fn);
ExprResult FixOverloadedFunctionReference(ExprResult,
                                          DeclAccessPair FoundDecl,
                                          FunctionDecl *Fn);

void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
                                 ArrayRef<Expr *> Args,
                                 OverloadCandidateSet &CandidateSet,
                                 bool PartialOverloading = false);
void AddOverloadedCallCandidates(
    LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
    ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet);

// An enum used to represent the different possible results of building a
// range-based for loop.
enum ForRangeStatus {
  FRS_Success,
  FRS_NoViableFunction,
  FRS_DiagnosticIssued
};

ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
                                         SourceLocation RangeLoc,
                                         const DeclarationNameInfo &NameInfo,
                                         LookupResult &MemberLookup,
                                         OverloadCandidateSet *CandidateSet,
                                         Expr *Range, ExprResult *CallExpr);

ExprResult BuildOverloadedCallExpr(Scope *S, Expr *Fn,
                                   UnresolvedLookupExpr *ULE,
                                   SourceLocation LParenLoc,
                                   MultiExprArg Args,
                                   SourceLocation RParenLoc,
                                   Expr *ExecConfig,
                                   bool AllowTypoCorrection=true,
                                   bool CalleesAddressIsTaken=false);

bool buildOverloadedCallSet(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE,
                            MultiExprArg Args, SourceLocation RParenLoc,
                            OverloadCandidateSet *CandidateSet,
                            ExprResult *Result);

ExprResult CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
                                      NestedNameSpecifierLoc NNSLoc,
                                      DeclarationNameInfo DNI,
                                      const UnresolvedSetImpl &Fns,
                                      bool PerformADL = true);

ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
                                   UnaryOperatorKind Opc,
                                   const UnresolvedSetImpl &Fns,
                                   Expr *input, bool RequiresADL = true);

void LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
                           OverloadedOperatorKind Op,
                           const UnresolvedSetImpl &Fns,
                           ArrayRef<Expr *> Args, bool RequiresADL = true);
ExprResult CreateOverloadedBinOp(SourceLocation OpLoc,
                                 BinaryOperatorKind Opc,
                                 const UnresolvedSetImpl &Fns,
                                 Expr *LHS, Expr *RHS,
                                 bool RequiresADL = true,
                                 bool AllowRewrittenCandidates = true,
                                 FunctionDecl *DefaultedFn = nullptr);
ExprResult BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,
                                              const UnresolvedSetImpl &Fns,
                                              Expr *LHS, Expr *RHS,
                                              FunctionDecl *DefaultedFn);

ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
                                              SourceLocation RLoc,
                                              Expr *Base,Expr *Idx);

ExprResult BuildCallToMemberFunction(Scope *S, Expr *MemExpr,
                                     SourceLocation LParenLoc,
                                     MultiExprArg Args,
                                     SourceLocation RParenLoc,
                                     bool AllowRecovery = false);
ExprResult
BuildCallToObjectOfClassType(Scope *S, Expr *Object, SourceLocation LParenLoc,
                             MultiExprArg Args,
                             SourceLocation RParenLoc);

ExprResult BuildOverloadedArrowExpr(Scope *S, Expr *Base,
                                    SourceLocation OpLoc,
                                    bool *NoArrowOperatorFound = nullptr);

/// CheckCallReturnType - Checks that a call expression's return type is
/// complete. Returns true on failure. The location passed in is the location
/// that best represents the call.
bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
                         CallExpr *CE, FunctionDecl *FD);

/// Helpers for dealing with blocks and functions.
bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
                              bool CheckParameterNames);
void CheckCXXDefaultArguments(FunctionDecl *FD);
void CheckExtraCXXDefaultArguments(Declarator &D);
Scope *getNonFieldDeclScope(Scope *S);

/// \name Name lookup
///
/// These routines provide name lookup that is used during semantic
/// analysis to resolve the various kinds of names (identifiers,
/// overloaded operator names, constructor names, etc.) into zero or
/// more declarations within a particular scope. The major entry
/// points are LookupName, which performs unqualified name lookup,
/// and LookupQualifiedName, which performs qualified name lookup.
///
/// All name lookup is performed based on some specific criteria,
/// which specify what names will be visible to name lookup and how
/// far name lookup should work. These criteria are important both
/// for capturing language semantics (certain lookups will ignore
/// certain names, for example) and for performance, since name
/// lookup is often a bottleneck in the compilation of C++. Name
/// lookup criteria is specified via the LookupCriteria enumeration.
///
/// The results of name lookup can vary based on the kind of name
/// lookup performed, the current language, and the translation
/// unit. In C, for example, name lookup will either return nothing
/// (no entity found) or a single declaration. In C++, name lookup
/// can additionally refer to a set of overloaded functions or
/// result in an ambiguity. All of the possible results of name
/// lookup are captured by the LookupResult class, which provides
/// the ability to distinguish among them.
//@{

/// Describes the kind of name lookup to perform.
enum LookupNameKind {
  /// Ordinary name lookup, which finds ordinary names (functions,
  /// variables, typedefs, etc.) in C and most kinds of names
  /// (functions, variables, members, types, etc.) in C++.
  LookupOrdinaryName = 0,
  /// Tag name lookup, which finds the names of enums, classes,
  /// structs, and unions.
  LookupTagName,
  /// Label name lookup.
  LookupLabel,
  /// Member name lookup, which finds the names of
  /// class/struct/union members.
  LookupMemberName,
  /// Look up of an operator name (e.g., operator+) for use with
  /// operator overloading. This lookup is similar to ordinary name
  /// lookup, but will ignore any declarations that are class members.
  LookupOperatorName,
  /// Look up a name following ~ in a destructor name. This is an ordinary
  /// lookup, but prefers tags to typedefs.
  LookupDestructorName,
  /// Look up of a name that precedes the '::' scope resolution
  /// operator in C++. This lookup completely ignores operator, object,
  /// function, and enumerator names (C++ [basic.lookup.qual]p1).
  LookupNestedNameSpecifierName,
  /// Look up a namespace name within a C++ using directive or
  /// namespace alias definition, ignoring non-namespace names (C++
  /// [basic.lookup.udir]p1).
  LookupNamespaceName,
  /// Look up all declarations in a scope with the given name,
  /// including resolved using declarations.  This is appropriate
  /// for checking redeclarations for a using declaration.
  LookupUsingDeclName,
  /// Look up an ordinary name that is going to be redeclared as a
  /// name with linkage. This lookup ignores any declarations that
  /// are outside of the current scope unless they have linkage. See
  /// C99 6.2.2p4-5 and C++ [basic.link]p6.
  LookupRedeclarationWithLinkage,
  /// Look up a friend of a local class. This lookup does not look
  /// outside the innermost non-class scope. See C++11 [class.friend]p11.
  LookupLocalFriendName,
  /// Look up the name of an Objective-C protocol.
  LookupObjCProtocolName,
  /// Look up implicit 'self' parameter of an objective-c method.
  LookupObjCImplicitSelfParam,
  /// Look up the name of an OpenMP user-defined reduction operation.
  LookupOMPReductionName,
  /// Look up the name of an OpenMP user-defined mapper.
  LookupOMPMapperName,
  /// Look up any declaration with any name.
  LookupAnyName
};

/// Specifies whether (or how) name lookup is being performed for a
/// redeclaration (vs. a reference).
enum RedeclarationKind {
  /// The lookup is a reference to this name that is not for the
  /// purpose of redeclaring the name.
  NotForRedeclaration = 0,
  /// The lookup results will be used for redeclaration of a name,
  /// if an entity by that name already exists and is visible.
  ForVisibleRedeclaration,
  /// The lookup results will be used for redeclaration of a name
  /// with external linkage; non-visible lookup results with external linkage
  /// may also be found.
  ForExternalRedeclaration
};

RedeclarationKind forRedeclarationInCurContext() {
  // A declaration with an owning module for linkage can never link against
  // anything that is not visible. We don't need to check linkage here; if
  // the context has internal linkage, redeclaration lookup won't find things
  // from other TUs, and we can't safely compute linkage yet in general.
  if (cast<Decl>(CurContext)
          ->getOwningModuleForLinkage(/*IgnoreLinkage*/true))
    return ForVisibleRedeclaration;
  return ForExternalRedeclaration;
}

/// The possible outcomes of name lookup for a literal operator.
enum LiteralOperatorLookupResult {
  /// The lookup resulted in an error.
  LOLR_Error,
  /// The lookup found no match but no diagnostic was issued.
  LOLR_ErrorNoDiagnostic,
  /// The lookup found a single 'cooked' literal operator, which
  /// expects a normal literal to be built and passed to it.
  LOLR_Cooked,
  /// The lookup found a single 'raw' literal operator, which expects
  /// a string literal containing the spelling of the literal token.
  LOLR_Raw,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the characters of the spelling of the literal token to be
  /// passed as a non-type template argument pack.
  LOLR_Template,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the character type and characters of the spelling of the
  /// string literal token to be passed as template arguments.
  LOLR_StringTemplatePack,
};

SpecialMemberOverloadResult LookupSpecialMember(CXXRecordDecl *D,
                                                CXXSpecialMember SM,
                                                bool ConstArg,
                                                bool VolatileArg,
                                                bool RValueThis,
                                                bool ConstThis,
                                                bool VolatileThis);

typedef std::function<void(const TypoCorrection &)> TypoDiagnosticGenerator;
typedef std::function<ExprResult(Sema &, TypoExpr *, TypoCorrection)>
    TypoRecoveryCallback;

4054private:
bool CppLookupName(LookupResult &R, Scope *S);

struct TypoExprState {
  std::unique_ptr<TypoCorrectionConsumer> Consumer;
  TypoDiagnosticGenerator DiagHandler;
  TypoRecoveryCallback RecoveryHandler;
  TypoExprState();
  TypoExprState(TypoExprState &&other) noexcept;
  TypoExprState &operator=(TypoExprState &&other) noexcept;
};

/// The set of unhandled TypoExprs and their associated state.
llvm::MapVector<TypoExpr *, TypoExprState> DelayedTypos;

/// Creates a new TypoExpr AST node.
TypoExpr *createDelayedTypo(std::unique_ptr<TypoCorrectionConsumer> TCC,
                            TypoDiagnosticGenerator TDG,
                            TypoRecoveryCallback TRC, SourceLocation TypoLoc);

// The set of known/encountered (unique, canonicalized) NamespaceDecls.
//
// The boolean value will be true to indicate that the namespace was loaded
// from an AST/PCH file, or false otherwise.
llvm::MapVector<NamespaceDecl*, bool> KnownNamespaces;

/// Whether we have already loaded known namespaces from an extenal
/// source.
bool LoadedExternalKnownNamespaces;

/// Helper for CorrectTypo and CorrectTypoDelayed used to create and
/// populate a new TypoCorrectionConsumer. Returns nullptr if typo correction
/// should be skipped entirely.
std::unique_ptr<TypoCorrectionConsumer>
makeTypoCorrectionConsumer(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind, Scope *S,
                           CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           DeclContext *MemberContext, bool EnteringContext,
                           const ObjCObjectPointerType *OPT,
                           bool ErrorRecovery);

4096public:
const TypoExprState &getTypoExprState(TypoExpr *TE) const;

/// Clears the state of the given TypoExpr.
void clearDelayedTypo(TypoExpr *TE);

/// Look up a name, looking for a single declaration.  Return
/// null if the results were absent, ambiguous, or overloaded.
///
/// It is preferable to use the elaborated form and explicitly handle
/// ambiguity and overloaded.
NamedDecl *LookupSingleName(Scope *S, DeclarationName Name,
                            SourceLocation Loc,
                            LookupNameKind NameKind,
                            RedeclarationKind Redecl
                              = NotForRedeclaration);
bool LookupBuiltin(LookupResult &R);
void LookupNecessaryTypesForBuiltin(Scope *S, unsigned ID);
bool LookupName(LookupResult &R, Scope *S,
                bool AllowBuiltinCreation = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         bool InUnqualifiedLookup = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         CXXScopeSpec &SS);
bool LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
                      bool AllowBuiltinCreation = false,
                      bool EnteringContext = false);
ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II, SourceLocation IdLoc,
                                 RedeclarationKind Redecl
                                   = NotForRedeclaration);
bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);

void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
                                  UnresolvedSetImpl &Functions);

LabelDecl *LookupOrCreateLabel(IdentifierInfo *II, SourceLocation IdentLoc,
                               SourceLocation GnuLabelLoc = SourceLocation());

DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
CXXConstructorDecl *LookupDefaultConstructor(CXXRecordDecl *Class);
CXXConstructorDecl *LookupCopyingConstructor(CXXRecordDecl *Class,
                                             unsigned Quals);
CXXMethodDecl *LookupCopyingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                       bool RValueThis, unsigned ThisQuals);
CXXConstructorDecl *LookupMovingConstructor(CXXRecordDecl *Class,
                                            unsigned Quals);
CXXMethodDecl *LookupMovingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                      bool RValueThis, unsigned ThisQuals);
CXXDestructorDecl *LookupDestructor(CXXRecordDecl *Class);

bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id,
                            bool IsUDSuffix);
LiteralOperatorLookupResult
LookupLiteralOperator(Scope *S, LookupResult &R, ArrayRef<QualType> ArgTys,
                      bool AllowRaw, bool AllowTemplate,
                      bool AllowStringTemplate, bool DiagnoseMissing,
                      StringLiteral *StringLit = nullptr);
bool isKnownName(StringRef name);

/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
enum class FunctionEmissionStatus {
  Emitted,
  CUDADiscarded,     // Discarded due to CUDA/HIP hostness
  OMPDiscarded,      // Discarded due to OpenMP hostness
  TemplateDiscarded, // Discarded due to uninstantiated templates
  Unknown,
};
FunctionEmissionStatus getEmissionStatus(FunctionDecl *Decl,
                                         bool Final = false);

// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);

void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
                             ArrayRef<Expr *> Args, ADLResult &Functions);

void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool LoadExternal = true);
void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool IncludeDependentBases = false,
                        bool LoadExternal = true);

enum CorrectTypoKind {
  CTK_NonError,     // CorrectTypo used in a non error recovery situation.
  CTK_ErrorRecovery // CorrectTypo used in normal error recovery.
};

TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind,
                           Scope *S, CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           CorrectTypoKind Mode,
                           DeclContext *MemberContext = nullptr,
                           bool EnteringContext = false,
                           const ObjCObjectPointerType *OPT = nullptr,
                           bool RecordFailure = true);

TypoExpr *CorrectTypoDelayed(const DeclarationNameInfo &Typo,
                             Sema::LookupNameKind LookupKind, Scope *S,
                             CXXScopeSpec *SS,
                             CorrectionCandidateCallback &CCC,
                             TypoDiagnosticGenerator TDG,
                             TypoRecoveryCallback TRC, CorrectTypoKind Mode,
                             DeclContext *MemberContext = nullptr,
                             bool EnteringContext = false,
                             const ObjCObjectPointerType *OPT = nullptr);

/// Process any TypoExprs in the given Expr and its children,
/// generating diagnostics as appropriate and returning a new Expr if there
/// were typos that were all successfully corrected and ExprError if one or
/// more typos could not be corrected.
///
/// \param E The Expr to check for TypoExprs.
///
/// \param InitDecl A VarDecl to avoid because the Expr being corrected is its
/// initializer.
///
/// \param RecoverUncorrectedTypos If true, when typo correction fails, it
/// will rebuild the given Expr with all TypoExprs degraded to RecoveryExprs.
///
/// \param Filter A function applied to a newly rebuilt Expr to determine if
/// it is an acceptable/usable result from a single combination of typo
/// corrections. As long as the filter returns ExprError, different
/// combinations of corrections will be tried until all are exhausted.
ExprResult CorrectDelayedTyposInExpr(
    Expr *E, VarDecl *InitDecl = nullptr,
    bool RecoverUncorrectedTypos = false,
    llvm::function_ref<ExprResult(Expr *)> Filter =
        [](Expr *E) -> ExprResult { return E; });

ExprResult CorrectDelayedTyposInExpr(
    ExprResult ER, VarDecl *InitDecl = nullptr,
    bool RecoverUncorrectedTypos = false,
    llvm::function_ref<ExprResult(Expr *)> Filter =
        [](Expr *E) -> ExprResult { return E; }) {
  return ER.isInvalid()
             ? ER
             : CorrectDelayedTyposInExpr(ER.get(), InitDecl,
                                         RecoverUncorrectedTypos, Filter);
}

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  bool ErrorRecovery = true);

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  const PartialDiagnostic &PrevNote,
                  bool ErrorRecovery = true);

void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);

void FindAssociatedClassesAndNamespaces(SourceLocation InstantiationLoc,
                                        ArrayRef<Expr *> Args,
                                 AssociatedNamespaceSet &AssociatedNamespaces,
                                 AssociatedClassSet &AssociatedClasses);

void FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                          bool ConsiderLinkage, bool AllowInlineNamespace);

bool CheckRedeclarationModuleOwnership(NamedDecl *New, NamedDecl *Old);

void DiagnoseAmbiguousLookup(LookupResult &Result);
//@}

/// Attempts to produce a RecoveryExpr after some AST node cannot be created.
ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
                              ArrayRef<Expr *> SubExprs,
                              QualType T = QualType());

ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
                                        SourceLocation IdLoc,
                                        bool TypoCorrection = false);
FunctionDecl *CreateBuiltin(IdentifierInfo *II, QualType Type, unsigned ID,
                            SourceLocation Loc);
NamedDecl *LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
                               Scope *S, bool ForRedeclaration,
                               SourceLocation Loc);
NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
                                    Scope *S);
void AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
    FunctionDecl *FD);
void AddKnownFunctionAttributes(FunctionDecl *FD);

// More parsing and symbol table subroutines.

void ProcessPragmaWeak(Scope *S, Decl *D);
// Decl attributes - this routine is the top level dispatcher.
void ProcessDeclAttributes(Scope *S, Decl *D, const Declarator &PD);
// Helper for delayed processing of attributes.
void ProcessDeclAttributeDelayed(Decl *D,
                                 const ParsedAttributesView &AttrList);
void ProcessDeclAttributeList(Scope *S, Decl *D, const ParsedAttributesView &AL,
                           bool IncludeCXX11Attributes = true);
bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
                                 const ParsedAttributesView &AttrList);

void checkUnusedDeclAttributes(Declarator &D);

/// Handles semantic checking for features that are common to all attributes,
/// such as checking whether a parameter was properly specified, or the
/// correct number of arguments were passed, etc. Returns true if the
/// attribute has been diagnosed.
bool checkCommonAttributeFeatures(const Decl *D, const ParsedAttr &A);
bool checkCommonAttributeFeatures(const Stmt *S, const ParsedAttr &A);

/// Determine if type T is a valid subject for a nonnull and similar
/// attributes. By default, we look through references (the behavior used by
/// nonnull), but if the second parameter is true, then we treat a reference
/// type as valid.
bool isValidPointerAttrType(QualType T, bool RefOkay = false);

bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
bool CheckCallingConvAttr(const ParsedAttr &attr, CallingConv &CC,
                          const FunctionDecl *FD = nullptr);
bool CheckAttrTarget(const ParsedAttr &CurrAttr);
bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
                                    StringRef &Str,
                                    SourceLocation *ArgLocation = nullptr);
llvm::Error isValidSectionSpecifier(StringRef Str);
bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
bool checkMSInheritanceAttrOnDefinition(
    CXXRecordDecl *RD, SourceRange Range, bool BestCase,
    MSInheritanceModel SemanticSpelling);

void CheckAlignasUnderalignment(Decl *D);

/// Adjust the calling convention of a method to be the ABI default if it
/// wasn't specified explicitly.  This handles method types formed from
/// function type typedefs and typename template arguments.
void adjustMemberFunctionCC(QualType &T, bool IsStatic, bool IsCtorOrDtor,
                            SourceLocation Loc);

// Check if there is an explicit attribute, but only look through parens.
// The intent is to look for an attribute on the current declarator, but not
// one that came from a typedef.
bool hasExplicitCallingConv(QualType T);

/// Get the outermost AttributedType node that sets a calling convention.
/// Valid types should not have multiple attributes with different CCs.
const AttributedType *getCallingConvAttributedType(QualType T) const;

/// Process the attributes before creating an attributed statement. Returns
/// the semantic attributes that have been processed.
void ProcessStmtAttributes(Stmt *Stmt,
                           const ParsedAttributesWithRange &InAttrs,
                           SmallVectorImpl<const Attr *> &OutAttrs);

void WarnConflictingTypedMethods(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *MethodDecl,
                                 bool IsProtocolMethodDecl);

void CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *Overridden,
                                 bool IsProtocolMethodDecl);

/// WarnExactTypedMethods - This routine issues a warning if method
/// implementation declaration matches exactly that of its declaration.
void WarnExactTypedMethods(ObjCMethodDecl *Method,
                           ObjCMethodDecl *MethodDecl,
                           bool IsProtocolMethodDecl);

typedef llvm::SmallPtrSet<Selector, 8> SelectorSet;

/// CheckImplementationIvars - This routine checks if the instance variables
/// listed in the implelementation match those listed in the interface.
void CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
                              ObjCIvarDecl **Fields, unsigned nIvars,
                              SourceLocation Loc);

/// ImplMethodsVsClassMethods - This is main routine to warn if any method
/// remains unimplemented in the class or category \@implementation.
void ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
                               ObjCContainerDecl* IDecl,
                               bool IncompleteImpl = false);

/// DiagnoseUnimplementedProperties - This routine warns on those properties
/// which must be implemented by this implementation.
void DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                     ObjCContainerDecl *CDecl,
                                     bool SynthesizeProperties);

/// Diagnose any null-resettable synthesized setters.
void diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl);

/// DefaultSynthesizeProperties - This routine default synthesizes all
/// properties which must be synthesized in the class's \@implementation.
void DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
                                 ObjCInterfaceDecl *IDecl,
                                 SourceLocation AtEnd);
void DefaultSynthesizeProperties(Scope *S, Decl *D, SourceLocation AtEnd);

/// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
/// an ivar synthesized for 'Method' and 'Method' is a property accessor
/// declared in class 'IFace'.
bool IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
                                    ObjCMethodDecl *Method, ObjCIvarDecl *IV);

/// DiagnoseUnusedBackingIvarInAccessor - Issue an 'unused' warning if ivar which
/// backs the property is not used in the property's accessor.
void DiagnoseUnusedBackingIvarInAccessor(Scope *S,
                                         const ObjCImplementationDecl *ImplD);

/// GetIvarBackingPropertyAccessor - If method is a property setter/getter and
/// it property has a backing ivar, returns this ivar; otherwise, returns NULL.
/// It also returns ivar's property on success.
ObjCIvarDecl *GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
                                             const ObjCPropertyDecl *&PDecl) const;

/// Called by ActOnProperty to handle \@property declarations in
/// class extensions.
ObjCPropertyDecl *HandlePropertyInClassExtension(Scope *S,
                    SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD,
                    Selector GetterSel,
                    SourceLocation GetterNameLoc,
                    Selector SetterSel,
                    SourceLocation SetterNameLoc,
                    const bool isReadWrite,
                    unsigned &Attributes,
                    const unsigned AttributesAsWritten,
                    QualType T,
                    TypeSourceInfo *TSI,
                    tok::ObjCKeywordKind MethodImplKind);

/// Called by ActOnProperty and HandlePropertyInClassExtension to
/// handle creating the ObjcPropertyDecl for a category or \@interface.
ObjCPropertyDecl *CreatePropertyDecl(Scope *S,
                                     ObjCContainerDecl *CDecl,
                                     SourceLocation AtLoc,
                                     SourceLocation LParenLoc,
                                     FieldDeclarator &FD,
                                     Selector GetterSel,
                                     SourceLocation GetterNameLoc,
                                     Selector SetterSel,
                                     SourceLocation SetterNameLoc,
                                     const bool isReadWrite,
                                     const unsigned Attributes,
                                     const unsigned AttributesAsWritten,
                                     QualType T,
                                     TypeSourceInfo *TSI,
                                     tok::ObjCKeywordKind MethodImplKind,
                                     DeclContext *lexicalDC = nullptr);

/// AtomicPropertySetterGetterRules - This routine enforces the rule (via
/// warning) when atomic property has one but not the other user-declared
/// setter or getter.
void AtomicPropertySetterGetterRules(ObjCImplDecl* IMPDecl,
                                     ObjCInterfaceDecl* IDecl);

void DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D);

void DiagnoseMissingDesignatedInitOverrides(
                                        const ObjCImplementationDecl *ImplD,
                                        const ObjCInterfaceDecl *IFD);

void DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID, ObjCInterfaceDecl *SID);

enum MethodMatchStrategy {
  MMS_loose,
  MMS_strict
};

/// MatchTwoMethodDeclarations - Checks if two methods' type match and returns
/// true, or false, accordingly.
bool MatchTwoMethodDeclarations(const ObjCMethodDecl *Method,
                                const ObjCMethodDecl *PrevMethod,
                                MethodMatchStrategy strategy = MMS_strict);

/// MatchAllMethodDeclarations - Check methods declaraed in interface or
/// or protocol against those declared in their implementations.
void MatchAllMethodDeclarations(const SelectorSet &InsMap,
                                const SelectorSet &ClsMap,
                                SelectorSet &InsMapSeen,
                                SelectorSet &ClsMapSeen,
                                ObjCImplDecl* IMPDecl,
                                ObjCContainerDecl* IDecl,
                                bool &IncompleteImpl,
                                bool ImmediateClass,
                                bool WarnCategoryMethodImpl=false);

/// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
/// category matches with those implemented in its primary class and
/// warns each time an exact match is found.
void CheckCategoryVsClassMethodMatches(ObjCCategoryImplDecl *CatIMP);

/// Add the given method to the list of globally-known methods.
void addMethodToGlobalList(ObjCMethodList *List, ObjCMethodDecl *Method);

/// Returns default addr space for method qualifiers.
LangAS getDefaultCXXMethodAddrSpace() const;

4495private:
/// AddMethodToGlobalPool - Add an instance or factory method to the global
/// pool. See descriptoin of AddInstanceMethodToGlobalPool.
void AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl, bool instance);

/// LookupMethodInGlobalPool - Returns the instance or factory method and
/// optionally warns if there are multiple signatures.
ObjCMethodDecl *LookupMethodInGlobalPool(Selector Sel, SourceRange R,
                                         bool receiverIdOrClass,
                                         bool instance);

4506public:
/// - Returns instance or factory methods in global method pool for
/// given selector. It checks the desired kind first, if none is found, and
/// parameter checkTheOther is set, it then checks the other kind. If no such
/// method or only one method is found, function returns false; otherwise, it
/// returns true.
bool
CollectMultipleMethodsInGlobalPool(Selector Sel,
                                   SmallVectorImpl<ObjCMethodDecl*>& Methods,
                                   bool InstanceFirst, bool CheckTheOther,
                                   const ObjCObjectType *TypeBound = nullptr);

bool
AreMultipleMethodsInGlobalPool(Selector Sel, ObjCMethodDecl *BestMethod,
                               SourceRange R, bool receiverIdOrClass,
                               SmallVectorImpl<ObjCMethodDecl*>& Methods);

void
DiagnoseMultipleMethodInGlobalPool(SmallVectorImpl<ObjCMethodDecl*> &Methods,
                                   Selector Sel, SourceRange R,
                                   bool receiverIdOrClass);

4528private:
/// - Returns a selector which best matches given argument list or
/// nullptr if none could be found
ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
                                 bool IsInstance,
                                 SmallVectorImpl<ObjCMethodDecl*>& Methods);


/// Record the typo correction failure and return an empty correction.
TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
                                bool RecordFailure = true) {
  if (RecordFailure)
    TypoCorrectionFailures[Typo].insert(TypoLoc);
  return TypoCorrection();
}

4544public:
/// AddInstanceMethodToGlobalPool - All instance methods in a translation
/// unit are added to a global pool. This allows us to efficiently associate
/// a selector with a method declaraation for purposes of typechecking
/// messages sent to "id" (where the class of the object is unknown).
void AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/true);
}

/// AddFactoryMethodToGlobalPool - Same as above, but for factory methods.
void AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/false);
}

/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
/// pool.
void AddAnyMethodToGlobalPool(Decl *D);

/// LookupInstanceMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupInstanceMethodInGlobalPool(Selector Sel, SourceRange R,
                                                 bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/true);
}

/// LookupFactoryMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupFactoryMethodInGlobalPool(Selector Sel, SourceRange R,
                                                bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/false);
}

const ObjCMethodDecl *SelectorsForTypoCorrection(Selector Sel,
                            QualType ObjectType=QualType());
/// LookupImplementedMethodInGlobalPool - Returns the method which has an
/// implementation.
ObjCMethodDecl *LookupImplementedMethodInGlobalPool(Selector Sel);

/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
/// initialization.
void CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
                                SmallVectorImpl<ObjCIvarDecl*> &Ivars);

//===--------------------------------------------------------------------===//
// Statement Parsing Callbacks: SemaStmt.cpp.
4591public:
class FullExprArg {
public:
  FullExprArg() : E(nullptr) { }
  FullExprArg(Sema &actions) : E(nullptr) { }

  ExprResult release() {
    return E;
  }

  Expr *get() const { return E; }

  Expr *operator->() {
    return E;
  }

private:
  // FIXME: No need to make the entire Sema class a friend when it's just
  // Sema::MakeFullExpr that needs access to the constructor below.
  friend class Sema;

  explicit FullExprArg(Expr *expr) : E(expr) {}

  Expr *E;
};

FullExprArg MakeFullExpr(Expr *Arg) {
  return MakeFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation());
}
FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
  return FullExprArg(
      ActOnFinishFullExpr(Arg, CC, /*DiscardedValue*/ false).get());
}
FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
  ExprResult FE =
      ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
                          /*DiscardedValue*/ true);
  return FullExprArg(FE.get());
}

StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
StmtResult ActOnExprStmtError();

StmtResult ActOnNullStmt(SourceLocation SemiLoc,
                         bool HasLeadingEmptyMacro = false);

void ActOnStartOfCompoundStmt(bool IsStmtExpr);
void ActOnAfterCompoundStatementLeadingPragmas();
void ActOnFinishOfCompoundStmt();
StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                             ArrayRef<Stmt *> Elts, bool isStmtExpr);

/// A RAII object to enter scope of a compound statement.
class CompoundScopeRAII {
public:
  CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
    S.ActOnStartOfCompoundStmt(IsStmtExpr);
  }

  ~CompoundScopeRAII() {
    S.ActOnFinishOfCompoundStmt();
  }

private:
  Sema &S;
};

/// An RAII helper that pops function a function scope on exit.
struct FunctionScopeRAII {
  Sema &S;
  bool Active;
  FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
  ~FunctionScopeRAII() {
    if (Active)
      S.PopFunctionScopeInfo();
  }
  void disable() { Active = false; }
};

StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl,
                                 SourceLocation StartLoc,
                                 SourceLocation EndLoc);
void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
StmtResult ActOnForEachLValueExpr(Expr *E);
ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
                         SourceLocation DotDotDotLoc, ExprResult RHS,
                         SourceLocation ColonLoc);
void ActOnCaseStmtBody(Stmt *CaseStmt, Stmt *SubStmt);

StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
                                    SourceLocation ColonLoc,
                                    Stmt *SubStmt, Scope *CurScope);
StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
                          SourceLocation ColonLoc, Stmt *SubStmt);

StmtResult BuildAttributedStmt(SourceLocation AttrsLoc,
                               ArrayRef<const Attr *> Attrs, Stmt *SubStmt);
StmtResult ActOnAttributedStmt(const ParsedAttributesWithRange &AttrList,
                               Stmt *SubStmt);

class ConditionResult;
StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       SourceLocation LParenLoc, Stmt *InitStmt,
                       ConditionResult Cond, SourceLocation RParenLoc,
                       Stmt *ThenVal, SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       SourceLocation LParenLoc, Stmt *InitStmt,
                       ConditionResult Cond, SourceLocation RParenLoc,
                       Stmt *ThenVal, SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
                                  SourceLocation LParenLoc, Stmt *InitStmt,
                                  ConditionResult Cond,
                                  SourceLocation RParenLoc);
StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                         Stmt *Switch, Stmt *Body);
StmtResult ActOnWhileStmt(SourceLocation WhileLoc, SourceLocation LParenLoc,
                          ConditionResult Cond, SourceLocation RParenLoc,
                          Stmt *Body);
StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
                       SourceLocation WhileLoc, SourceLocation CondLParen,
                       Expr *Cond, SourceLocation CondRParen);

StmtResult ActOnForStmt(SourceLocation ForLoc,
                        SourceLocation LParenLoc,
                        Stmt *First,
                        ConditionResult Second,
                        FullExprArg Third,
                        SourceLocation RParenLoc,
                        Stmt *Body);
ExprResult CheckObjCForCollectionOperand(SourceLocation forLoc,
                                         Expr *collection);
StmtResult ActOnObjCForCollectionStmt(SourceLocation ForColLoc,
                                      Stmt *First, Expr *collection,
                                      SourceLocation RParenLoc);
StmtResult FinishObjCForCollectionStmt(Stmt *ForCollection, Stmt *Body);

enum BuildForRangeKind {
  /// Initial building of a for-range statement.
  BFRK_Build,
  /// Instantiation or recovery rebuild of a for-range statement. Don't
  /// attempt any typo-correction.
  BFRK_Rebuild,
  /// Determining whether a for-range statement could be built. Avoid any
  /// unnecessary or irreversible actions.
  BFRK_Check
};

StmtResult ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                Stmt *LoopVar,
                                SourceLocation ColonLoc, Expr *Collection,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult BuildCXXForRangeStmt(SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                SourceLocation ColonLoc,
                                Stmt *RangeDecl, Stmt *Begin, Stmt *End,
                                Expr *Cond, Expr *Inc,
                                Stmt *LoopVarDecl,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult FinishCXXForRangeStmt(Stmt *ForRange, Stmt *Body);

StmtResult ActOnGotoStmt(SourceLocation GotoLoc,
                         SourceLocation LabelLoc,
                         LabelDecl *TheDecl);
StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
                                 SourceLocation StarLoc,
                                 Expr *DestExp);
StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope);
StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope);

void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind, unsigned NumParams);
typedef std::pair<StringRef, QualType> CapturedParamNameType;
void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind,
                              ArrayRef<CapturedParamNameType> Params,
                              unsigned OpenMPCaptureLevel = 0);
StmtResult ActOnCapturedRegionEnd(Stmt *S);
void ActOnCapturedRegionError();
RecordDecl *CreateCapturedStmtRecordDecl(CapturedDecl *&CD,
                                         SourceLocation Loc,
                                         unsigned NumParams);

struct NamedReturnInfo {
  const VarDecl *Candidate;

  enum Status : uint8_t { None, MoveEligible, MoveEligibleAndCopyElidable };
  Status S;

  bool isMoveEligible() const { return S != None; };
  bool isCopyElidable() const { return S == MoveEligibleAndCopyElidable; }
};
enum class SimplerImplicitMoveMode { ForceOff, Normal, ForceOn };
NamedReturnInfo getNamedReturnInfo(
    Expr *&E, SimplerImplicitMoveMode Mode = SimplerImplicitMoveMode::Normal);
NamedReturnInfo getNamedReturnInfo(const VarDecl *VD);
const VarDecl *getCopyElisionCandidate(NamedReturnInfo &Info,
                                       QualType ReturnType);

ExprResult
PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
                                const NamedReturnInfo &NRInfo, Expr *Value,
                                bool SupressSimplerImplicitMoves = false);

StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                           Scope *CurScope);
StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);
StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                                   NamedReturnInfo &NRInfo,
                                   bool SupressSimplerImplicitMoves);

StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                           bool IsVolatile, unsigned NumOutputs,
                           unsigned NumInputs, IdentifierInfo **Names,
                           MultiExprArg Constraints, MultiExprArg Exprs,
                           Expr *AsmString, MultiExprArg Clobbers,
                           unsigned NumLabels,
                           SourceLocation RParenLoc);

void FillInlineAsmIdentifierInfo(Expr *Res,
                                 llvm::InlineAsmIdentifierInfo &Info);
ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                                     UnqualifiedId &Id,
                                     bool IsUnevaluatedContext);
bool LookupInlineAsmField(StringRef Base, StringRef Member,
                          unsigned &Offset, SourceLocation AsmLoc);
ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
                                       SourceLocation AsmLoc);
StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                          ArrayRef<Token> AsmToks,
                          StringRef AsmString,
                          unsigned NumOutputs, unsigned NumInputs,
                          ArrayRef<StringRef> Constraints,
                          ArrayRef<StringRef> Clobbers,
                          ArrayRef<Expr*> Exprs,
                          SourceLocation EndLoc);
LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
                                 SourceLocation Location,
                                 bool AlwaysCreate);

VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                SourceLocation StartLoc,
                                SourceLocation IdLoc, IdentifierInfo *Id,
                                bool Invalid = false);

Decl *ActOnObjCExceptionDecl(Scope *S, Declarator &D);

StmtResult ActOnObjCAtCatchStmt(SourceLocation AtLoc, SourceLocation RParen,
                                Decl *Parm, Stmt *Body);

StmtResult ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body);

StmtResult ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
                              MultiStmtArg Catch, Stmt *Finally);

StmtResult BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw);
StmtResult ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
                                Scope *CurScope);
ExprResult ActOnObjCAtSynchronizedOperand(SourceLocation atLoc,
                                          Expr *operand);
StmtResult ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc,
                                       Expr *SynchExpr,
                                       Stmt *SynchBody);

StmtResult ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body);

VarDecl *BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                   SourceLocation StartLoc,
                                   SourceLocation IdLoc,
                                   IdentifierInfo *Id);

Decl *ActOnExceptionDeclarator(Scope *S, Declarator &D);

StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc,
                              Decl *ExDecl, Stmt *HandlerBlock);
StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
                            ArrayRef<Stmt *> Handlers);

StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
                            SourceLocation TryLoc, Stmt *TryBlock,
                            Stmt *Handler);
StmtResult ActOnSEHExceptBlock(SourceLocation Loc,
                               Expr *FilterExpr,
                               Stmt *Block);
void ActOnStartSEHFinallyBlock();
void ActOnAbortSEHFinallyBlock();
StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);

void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);

bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const;

/// If it's a file scoped decl that must warn if not used, keep track
/// of it.
void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);

/// DiagnoseUnusedExprResult - If the statement passed in is an expression
/// whose result is unused, warn.
void DiagnoseUnusedExprResult(const Stmt *S);
void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
void DiagnoseUnusedDecl(const NamedDecl *ND);

/// If VD is set but not otherwise used, diagnose, for a parameter or a
/// variable.
void DiagnoseUnusedButSetDecl(const VarDecl *VD);

/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
/// statement as a \p Body, and it is located on the same line.
///
/// This helps prevent bugs due to typos, such as:
///     if (condition);
///       do_stuff();
void DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
                           const Stmt *Body,
                           unsigned DiagID);

/// Warn if a for/while loop statement \p S, which is followed by
/// \p PossibleBody, has a suspicious null statement as a body.
void DiagnoseEmptyLoopBody(const Stmt *S,
                           const Stmt *PossibleBody);

/// Warn if a value is moved to itself.
void DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
                      SourceLocation OpLoc);

/// Warn if we're implicitly casting from a _Nullable pointer type to a
/// _Nonnull one.
void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
                                         SourceLocation Loc);

/// Warn when implicitly casting 0 to nullptr.
void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);

ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
  return DelayedDiagnostics.push(pool);
}
void PopParsingDeclaration(ParsingDeclState state, Decl *decl);

typedef ProcessingContextState ParsingClassState;
ParsingClassState PushParsingClass() {
  ParsingClassDepth++;
  return DelayedDiagnostics.pushUndelayed();
}
void PopParsingClass(ParsingClassState state) {
  ParsingClassDepth--;
  DelayedDiagnostics.popUndelayed(state);
}

void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);

void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                                const ObjCInterfaceDecl *UnknownObjCClass,
                                bool ObjCPropertyAccess,
                                bool AvoidPartialAvailabilityChecks = false,
                                ObjCInterfaceDecl *ClassReceiver = nullptr);

bool makeUnavailableInSystemHeader(SourceLocation loc,
                                   UnavailableAttr::ImplicitReason reason);

/// Issue any -Wunguarded-availability warnings in \c FD
void DiagnoseUnguardedAvailabilityViolations(Decl *FD);

void handleDelayedAvailabilityCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

//===--------------------------------------------------------------------===//
// Expression Parsing Callbacks: SemaExpr.cpp.

bool CanUseDecl(NamedDecl *D, bool TreatUnavailableAsInvalid);
bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                       const ObjCInterfaceDecl *UnknownObjCClass = nullptr,
                       bool ObjCPropertyAccess = false,
                       bool AvoidPartialAvailabilityChecks = false,
                       ObjCInterfaceDecl *ClassReciever = nullptr);
void NoteDeletedFunction(FunctionDecl *FD);
void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
bool DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *PD,
                                      ObjCMethodDecl *Getter,
                                      SourceLocation Loc);
void DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
                           ArrayRef<Expr *> Args);

void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, Decl *LambdaContextDecl = nullptr,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
void PopExpressionEvaluationContext();

void DiscardCleanupsInEvaluationContext();

ExprResult TransformToPotentiallyEvaluated(Expr *E);
ExprResult HandleExprEvaluationContextForTypeof(Expr *E);

ExprResult CheckUnevaluatedOperand(Expr *E);
void CheckUnusedVolatileAssignment(Expr *E);

ExprResult ActOnConstantExpression(ExprResult Res);

// Functions for marking a declaration referenced.  These functions also
// contain the relevant logic for marking if a reference to a function or
// variable is an odr-use (in the C++11 sense).  There are separate variants
// for expressions referring to a decl; these exist because odr-use marking
// needs to be delayed for some constant variables when we build one of the
// named expressions.
//
// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
// should usually be true. This only needs to be set to false if the lack of
// odr-use cannot be determined from the current context (for instance,
// because the name denotes a virtual function and was written without an
// explicit nested-name-specifier).
void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool MightBeOdrUse);
void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
                            bool MightBeOdrUse = true);
void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
void MarkDeclRefReferenced(DeclRefExpr *E, const Expr *Base = nullptr);
void MarkMemberReferenced(MemberExpr *E);
void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
void MarkCaptureUsedInEnclosingContext(VarDecl *Capture, SourceLocation Loc,
                                       unsigned CapturingScopeIndex);

ExprResult CheckLValueToRValueConversionOperand(Expr *E);
void CleanupVarDeclMarking();

enum TryCaptureKind {
  TryCapture_Implicit, TryCapture_ExplicitByVal, TryCapture_ExplicitByRef
};

/// Try to capture the given variable.
///
/// \param Var The variable to capture.
///
/// \param Loc The location at which the capture occurs.
///
/// \param Kind The kind of capture, which may be implicit (for either a
/// block or a lambda), or explicit by-value or by-reference (for a lambda).
///
/// \param EllipsisLoc The location of the ellipsis, if one is provided in
/// an explicit lambda capture.
///
/// \param BuildAndDiagnose Whether we are actually supposed to add the
/// captures or diagnose errors. If false, this routine merely check whether
/// the capture can occur without performing the capture itself or complaining
/// if the variable cannot be captured.
///
/// \param CaptureType Will be set to the type of the field used to capture
/// this variable in the innermost block or lambda. Only valid when the
/// variable can be captured.
///
/// \param DeclRefType Will be set to the type of a reference to the capture
/// from within the current scope. Only valid when the variable can be
/// captured.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// variables that may or may not be used in certain specializations of
/// a nested generic lambda.
///
/// \returns true if an error occurred (i.e., the variable cannot be
/// captured) and false if the capture succeeded.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc, TryCaptureKind Kind,
                        SourceLocation EllipsisLoc, bool BuildAndDiagnose,
                        QualType &CaptureType,
                        QualType &DeclRefType,
                        const unsigned *const FunctionScopeIndexToStopAt);

/// Try to capture the given variable.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc,
                        TryCaptureKind Kind = TryCapture_Implicit,
                        SourceLocation EllipsisLoc = SourceLocation());

/// Checks if the variable must be captured.
bool NeedToCaptureVariable(VarDecl *Var, SourceLocation Loc);

/// Given a variable, determine the type that a reference to that
/// variable will have in the given scope.
QualType getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc);

/// Mark all of the declarations referenced within a particular AST node as
/// referenced. Used when template instantiation instantiates a non-dependent
/// type -- entities referenced by the type are now referenced.
void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
void MarkDeclarationsReferencedInExpr(Expr *E,
                                      bool SkipLocalVariables = false);

/// Try to recover by turning the given expression into a
/// call.  Returns true if recovery was attempted or an error was
/// emitted; this may also leave the ExprResult invalid.
bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
                          bool ForceComplain = false,
                          bool (*IsPlausibleResult)(QualType) = nullptr);

/// Figure out if an expression could be turned into a call.
bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
                   UnresolvedSetImpl &NonTemplateOverloads);

/// Try to convert an expression \p E to type \p Ty. Returns the result of the
/// conversion.
ExprResult tryConvertExprToType(Expr *E, QualType Ty);

/// Conditionally issue a diagnostic based on the current
/// evaluation context.
///
/// \param Statement If Statement is non-null, delay reporting the
/// diagnostic until the function body is parsed, and then do a basic
/// reachability analysis to determine if the statement is reachable.
/// If it is unreachable, the diagnostic will not be emitted.
bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
                         const PartialDiagnostic &PD);
/// Similar, but diagnostic is only produced if all the specified statements
/// are reachable.
bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt*> Stmts,
                         const PartialDiagnostic &PD);

// Primary Expressions.
SourceRange getExprRange(Expr *E) const;

ExprResult ActOnIdExpression(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    UnqualifiedId &Id, bool HasTrailingLParen, bool IsAddressOfOperand,
    CorrectionCandidateCallback *CCC = nullptr,
    bool IsInlineAsmIdentifier = false, Token *KeywordReplacement = nullptr);

void DecomposeUnqualifiedId(const UnqualifiedId &Id,
                            TemplateArgumentListInfo &Buffer,
                            DeclarationNameInfo &NameInfo,
                            const TemplateArgumentListInfo *&TemplateArgs);

bool DiagnoseDependentMemberLookup(LookupResult &R);

bool
DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
                    CorrectionCandidateCallback &CCC,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    ArrayRef<Expr *> Args = None, TypoExpr **Out = nullptr);

DeclResult LookupIvarInObjCMethod(LookupResult &Lookup, Scope *S,
                                  IdentifierInfo *II);
ExprResult BuildIvarRefExpr(Scope *S, SourceLocation Loc, ObjCIvarDecl *IV);

ExprResult LookupInObjCMethod(LookupResult &LookUp, Scope *S,
                              IdentifierInfo *II,
                              bool AllowBuiltinCreation=false);

ExprResult ActOnDependentIdExpression(const CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      const DeclarationNameInfo &NameInfo,
                                      bool isAddressOfOperand,
                              const TemplateArgumentListInfo *TemplateArgs);

/// If \p D cannot be odr-used in the current expression evaluation context,
/// return a reason explaining why. Otherwise, return NOUR_None.
NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);

DeclRefExpr *BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                              SourceLocation Loc,
                              const CXXScopeSpec *SS = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 const CXXScopeSpec *SS = nullptr,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 NestedNameSpecifierLoc NNS,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);

ExprResult
BuildAnonymousStructUnionMemberReference(
    const CXXScopeSpec &SS,
    SourceLocation nameLoc,
    IndirectFieldDecl *indirectField,
    DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_none),
    Expr *baseObjectExpr = nullptr,
    SourceLocation opLoc = SourceLocation());

ExprResult BuildPossibleImplicitMemberExpr(
    const CXXScopeSpec &SS, SourceLocation TemplateKWLoc, LookupResult &R,
    const TemplateArgumentListInfo *TemplateArgs, const Scope *S,
    UnresolvedLookupExpr *AsULE = nullptr);
ExprResult BuildImplicitMemberExpr(const CXXScopeSpec &SS,
                                   SourceLocation TemplateKWLoc,
                                   LookupResult &R,
                              const TemplateArgumentListInfo *TemplateArgs,
                                   bool IsDefiniteInstance,
                                   const Scope *S);
bool UseArgumentDependentLookup(const CXXScopeSpec &SS,
                                const LookupResult &R,
                                bool HasTrailingLParen);

ExprResult
BuildQualifiedDeclarationNameExpr(CXXScopeSpec &SS,
                                  const DeclarationNameInfo &NameInfo,
                                  bool IsAddressOfOperand, const Scope *S,
                                  TypeSourceInfo **RecoveryTSI = nullptr);

ExprResult BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                              const DeclarationNameInfo &NameInfo,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS,
                                    LookupResult &R,
                                    bool NeedsADL,
                                    bool AcceptInvalidDecl = false);
ExprResult BuildDeclarationNameExpr(
    const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
    NamedDecl *FoundD = nullptr,
    const TemplateArgumentListInfo *TemplateArgs = nullptr,
    bool AcceptInvalidDecl = false);

ExprResult BuildLiteralOperatorCall(LookupResult &R,
                    DeclarationNameInfo &SuffixInfo,
                    ArrayRef<Expr *> Args,
                    SourceLocation LitEndLoc,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr);

ExprResult BuildPredefinedExpr(SourceLocation Loc,
                               PredefinedExpr::IdentKind IK);
ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
ExprResult ActOnIntegerConstant(SourceLocation Loc, uint64_t Val);

ExprResult BuildSYCLUniqueStableNameExpr(SourceLocation OpLoc,
                                         SourceLocation LParen,
                                         SourceLocation RParen,
                                         TypeSourceInfo *TSI);
ExprResult ActOnSYCLUniqueStableNameExpr(SourceLocation OpLoc,
                                         SourceLocation LParen,
                                         SourceLocation RParen,
                                         ParsedType ParsedTy);

bool CheckLoopHintExpr(Expr *E, SourceLocation Loc);

ExprResult ActOnNumericConstant(const Token &Tok, Scope *UDLScope = nullptr);
ExprResult ActOnCharacterConstant(const Token &Tok,
                                  Scope *UDLScope = nullptr);
ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
ExprResult ActOnParenListExpr(SourceLocation L,
                              SourceLocation R,
                              MultiExprArg Val);

/// ActOnStringLiteral - The specified tokens were lexed as pasted string
/// fragments (e.g. "foo" "bar" L"baz").
ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
                              Scope *UDLScope = nullptr);

ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
                                     SourceLocation DefaultLoc,
                                     SourceLocation RParenLoc,
                                     Expr *ControllingExpr,
                                     ArrayRef<ParsedType> ArgTypes,
                                     ArrayRef<Expr *> ArgExprs);
ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
                                      SourceLocation DefaultLoc,
                                      SourceLocation RParenLoc,
                                      Expr *ControllingExpr,
                                      ArrayRef<TypeSourceInfo *> Types,
                                      ArrayRef<Expr *> Exprs);

// Binary/Unary Operators.  'Tok' is the token for the operator.
ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
                                Expr *InputExpr);
ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc,
                        UnaryOperatorKind Opc, Expr *Input);
ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc,
                        tok::TokenKind Op, Expr *Input);

bool isQualifiedMemberAccess(Expr *E);
QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);

ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
                                          SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind,
                                          SourceRange R);
ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind);
ExprResult
  ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
                                UnaryExprOrTypeTrait ExprKind,
                                bool IsType, void *TyOrEx,
                                SourceRange ArgRange);

ExprResult CheckPlaceholderExpr(Expr *E);
bool CheckVecStepExpr(Expr *E);

bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
                                      SourceRange ExprRange,
                                      UnaryExprOrTypeTrait ExprKind);
ExprResult ActOnSizeofParameterPackExpr(Scope *S,
                                        SourceLocation OpLoc,
                                        IdentifierInfo &Name,
                                        SourceLocation NameLoc,
                                        SourceLocation RParenLoc);
ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                               tok::TokenKind Kind, Expr *Input);

ExprResult ActOnArraySubscriptExpr(Scope *S, Expr *Base, SourceLocation LLoc,
                                   Expr *Idx, SourceLocation RLoc);
ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
                                           Expr *Idx, SourceLocation RLoc);

ExprResult CreateBuiltinMatrixSubscriptExpr(Expr *Base, Expr *RowIdx,
                                            Expr *ColumnIdx,
                                            SourceLocation RBLoc);

ExprResult ActOnOMPArraySectionExpr(Expr *Base, SourceLocation LBLoc,
                                    Expr *LowerBound,
                                    SourceLocation ColonLocFirst,
                                    SourceLocation ColonLocSecond,
                                    Expr *Length, Expr *Stride,
                                    SourceLocation RBLoc);
ExprResult ActOnOMPArrayShapingExpr(Expr *Base, SourceLocation LParenLoc,
                                    SourceLocation RParenLoc,
                                    ArrayRef<Expr *> Dims,
                                    ArrayRef<SourceRange> Brackets);

/// Data structure for iterator expression.
struct OMPIteratorData {
  IdentifierInfo *DeclIdent = nullptr;
  SourceLocation DeclIdentLoc;
  ParsedType Type;
  OMPIteratorExpr::IteratorRange Range;
  SourceLocation AssignLoc;
  SourceLocation ColonLoc;
  SourceLocation SecColonLoc;
};

ExprResult ActOnOMPIteratorExpr(Scope *S, SourceLocation IteratorKwLoc,
                                SourceLocation LLoc, SourceLocation RLoc,
                                ArrayRef<OMPIteratorData> Data);

// This struct is for use by ActOnMemberAccess to allow
// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
// changing the access operator from a '.' to a '->' (to see if that is the
// change needed to fix an error about an unknown member, e.g. when the class
// defines a custom operator->).
struct ActOnMemberAccessExtraArgs {
  Scope *S;
  UnqualifiedId &Id;
  Decl *ObjCImpDecl;
};

ExprResult BuildMemberReferenceExpr(
    Expr *Base, QualType BaseType, SourceLocation OpLoc, bool IsArrow,
    CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
    const TemplateArgumentListInfo *TemplateArgs,
    const Scope *S,
    ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult
BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
                         bool IsArrow, const CXXScopeSpec &SS,
                         SourceLocation TemplateKWLoc,
                         NamedDecl *FirstQualifierInScope, LookupResult &R,
                         const TemplateArgumentListInfo *TemplateArgs,
                         const Scope *S,
                         bool SuppressQualifierCheck = false,
                         ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult BuildFieldReferenceExpr(Expr *BaseExpr, bool IsArrow,
                                   SourceLocation OpLoc,
                                   const CXXScopeSpec &SS, FieldDecl *Field,
                                   DeclAccessPair FoundDecl,
                                   const DeclarationNameInfo &MemberNameInfo);

ExprResult PerformMemberExprBaseConversion(Expr *Base, bool IsArrow);

bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
                                   const CXXScopeSpec &SS,
                                   const LookupResult &R);

ExprResult ActOnDependentMemberExpr(Expr *Base, QualType BaseType,
                                    bool IsArrow, SourceLocation OpLoc,
                                    const CXXScopeSpec &SS,
                                    SourceLocation TemplateKWLoc,
                                    NamedDecl *FirstQualifierInScope,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult ActOnMemberAccessExpr(Scope *S, Expr *Base,
                                 SourceLocation OpLoc,
                                 tok::TokenKind OpKind,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 UnqualifiedId &Member,
                                 Decl *ObjCImpDecl);

MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                const CXXScopeSpec *SS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);
MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);

void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
bool ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
                             FunctionDecl *FDecl,
                             const FunctionProtoType *Proto,
                             ArrayRef<Expr *> Args,
                             SourceLocation RParenLoc,
                             bool ExecConfig = false);
void CheckStaticArrayArgument(SourceLocation CallLoc,
                              ParmVarDecl *Param,
                              const Expr *ArgExpr);

/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
ExprResult ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr);
ExprResult BuildCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr,
                         bool IsExecConfig = false,
                         bool AllowRecovery = false);
Expr *BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
                           MultiExprArg CallArgs);
enum class AtomicArgumentOrder { API, AST };
ExprResult
BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
                SourceLocation RParenLoc, MultiExprArg Args,
                AtomicExpr::AtomicOp Op,
                AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
ExprResult
BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl, SourceLocation LParenLoc,
                      ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
                      Expr *Config = nullptr, bool IsExecConfig = false,
                      ADLCallKind UsesADL = ADLCallKind::NotADL);

ExprResult ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc,
                                   MultiExprArg ExecConfig,
                                   SourceLocation GGGLoc);

ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
                         Declarator &D, ParsedType &Ty,
                         SourceLocation RParenLoc, Expr *CastExpr);
ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc,
                               TypeSourceInfo *Ty,
                               SourceLocation RParenLoc,
                               Expr *Op);
CastKind PrepareScalarCast(ExprResult &src, QualType destType);

/// Build an altivec or OpenCL literal.
ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
                              SourceLocation RParenLoc, Expr *E,
                              TypeSourceInfo *TInfo);

ExprResult MaybeConvertParenListExprToParenExpr(Scope *S, Expr *ME);

ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc,
                                ParsedType Ty,
                                SourceLocation RParenLoc,
                                Expr *InitExpr);

ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
                                    TypeSourceInfo *TInfo,
                                    SourceLocation RParenLoc,
                                    Expr *LiteralExpr);

ExprResult ActOnInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult BuildInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult ActOnDesignatedInitializer(Designation &Desig,
                                      SourceLocation EqualOrColonLoc,
                                      bool GNUSyntax,
                                      ExprResult Init);

5492private:
static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);

5495public:
ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc,
                      tok::TokenKind Kind, Expr *LHSExpr, Expr *RHSExpr);
ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc,
                      BinaryOperatorKind Opc, Expr *LHSExpr, Expr *RHSExpr);
ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
                              Expr *LHSExpr, Expr *RHSExpr);
void LookupBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
                 UnresolvedSetImpl &Functions);

void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);

/// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
/// in the case of a the GNU conditional expr extension.
ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
                              SourceLocation ColonLoc,
                              Expr *CondExpr, Expr *LHSExpr, Expr *RHSExpr);

/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                          LabelDecl *TheDecl);

void ActOnStartStmtExpr();
ExprResult ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,
                         SourceLocation RPLoc);
ExprResult BuildStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                         SourceLocation RPLoc, unsigned TemplateDepth);
// Handle the final expression in a statement expression.
ExprResult ActOnStmtExprResult(ExprResult E);
void ActOnStmtExprError();

// __builtin_offsetof(type, identifier(.identifier|[expr])*)
struct OffsetOfComponent {
  SourceLocation LocStart, LocEnd;
  bool isBrackets;  // true if [expr], false if .ident
  union {
    IdentifierInfo *IdentInfo;
    Expr *E;
  } U;
};

/// __builtin_offsetof(type, a.b[123][456].c)
ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
                                TypeSourceInfo *TInfo,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);
ExprResult ActOnBuiltinOffsetOf(Scope *S,
                                SourceLocation BuiltinLoc,
                                SourceLocation TypeLoc,
                                ParsedType ParsedArgTy,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);

// __builtin_choose_expr(constExpr, expr1, expr2)
ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc,
                           Expr *CondExpr, Expr *LHSExpr,
                           Expr *RHSExpr, SourceLocation RPLoc);

// __builtin_va_arg(expr, type)
ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
                      SourceLocation RPLoc);
ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
                          TypeSourceInfo *TInfo, SourceLocation RPLoc);

// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FILE(),
// __builtin_COLUMN()
ExprResult ActOnSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc,
                              SourceLocation RPLoc);

// Build a potentially resolved SourceLocExpr.
ExprResult BuildSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc, SourceLocation RPLoc,
                              DeclContext *ParentContext);

// __null
ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);

bool CheckCaseExpression(Expr *E);

/// Describes the result of an "if-exists" condition check.
enum IfExistsResult {
  /// The symbol exists.
  IER_Exists,

  /// The symbol does not exist.
  IER_DoesNotExist,

  /// The name is a dependent name, so the results will differ
  /// from one instantiation to the next.
  IER_Dependent,

  /// An error occurred.
  IER_Error
};

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
                             const DeclarationNameInfo &TargetNameInfo);

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, SourceLocation KeywordLoc,
                             bool IsIfExists, CXXScopeSpec &SS,
                             UnqualifiedId &Name);

StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      NestedNameSpecifierLoc QualifierLoc,
                                      DeclarationNameInfo NameInfo,
                                      Stmt *Nested);
StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      CXXScopeSpec &SS, UnqualifiedId &Name,
                                      Stmt *Nested);

//===------------------------- "Block" Extension ------------------------===//

/// ActOnBlockStart - This callback is invoked when a block literal is
/// started.
void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockArguments - This callback allows processing of block arguments.
/// If there are no arguments, this is still invoked.
void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
                         Scope *CurScope);

/// ActOnBlockError - If there is an error parsing a block, this callback
/// is invoked to pop the information about the block from the action impl.
void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockStmtExpr - This is called when the body of a block statement
/// literal was successfully completed.  ^(int x){...}
ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
                              Scope *CurScope);

//===---------------------------- Clang Extensions ----------------------===//

/// __builtin_convertvector(...)
ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
                                  SourceLocation BuiltinLoc,
                                  SourceLocation RParenLoc);

//===---------------------------- OpenCL Features -----------------------===//

/// __builtin_astype(...)
ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
                           SourceLocation BuiltinLoc,
                           SourceLocation RParenLoc);
ExprResult BuildAsTypeExpr(Expr *E, QualType DestTy,
                           SourceLocation BuiltinLoc,
                           SourceLocation RParenLoc);

//===---------------------------- C++ Features --------------------------===//

// Act on C++ namespaces
Decl *ActOnStartNamespaceDef(Scope *S, SourceLocation InlineLoc,
                             SourceLocation NamespaceLoc,
                             SourceLocation IdentLoc, IdentifierInfo *Ident,
                             SourceLocation LBrace,
                             const ParsedAttributesView &AttrList,
                             UsingDirectiveDecl *&UsingDecl);
void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);

NamespaceDecl *getStdNamespace() const;
NamespaceDecl *getOrCreateStdNamespace();

NamespaceDecl *lookupStdExperimentalNamespace();

CXXRecordDecl *getStdBadAlloc() const;
EnumDecl *getStdAlignValT() const;

5666private:
// A cache representing if we've fully checked the various comparison category
// types stored in ASTContext. The bit-index corresponds to the integer value
// of a ComparisonCategoryType enumerator.
llvm::SmallBitVector FullyCheckedComparisonCategories;

ValueDecl *tryLookupCtorInitMemberDecl(CXXRecordDecl *ClassDecl,
                                       CXXScopeSpec &SS,
                                       ParsedType TemplateTypeTy,
                                       IdentifierInfo *MemberOrBase);

5677public:
enum class ComparisonCategoryUsage {
  /// The '<=>' operator was used in an expression and a builtin operator
  /// was selected.
  OperatorInExpression,
  /// A defaulted 'operator<=>' needed the comparison category. This
  /// typically only applies to 'std::strong_ordering', due to the implicit
  /// fallback return value.
  DefaultedOperator,
};

/// Lookup the specified comparison category types in the standard
///   library, an check the VarDecls possibly returned by the operator<=>
///   builtins for that type.
///
/// \return The type of the comparison category type corresponding to the
///   specified Kind, or a null type if an error occurs
QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
                                     SourceLocation Loc,
                                     ComparisonCategoryUsage Usage);

/// Tests whether Ty is an instance of std::initializer_list and, if
/// it is and Element is not NULL, assigns the element type to Element.
bool isStdInitializerList(QualType Ty, QualType *Element);

/// Looks for the std::initializer_list template and instantiates it
/// with Element, or emits an error if it's not found.
///
/// \returns The instantiated template, or null on error.
QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);

/// Determine whether Ctor is an initializer-list constructor, as
/// defined in [dcl.init.list]p2.
bool isInitListConstructor(const FunctionDecl *Ctor);

Decl *ActOnUsingDirective(Scope *CurScope, SourceLocation UsingLoc,
                          SourceLocation NamespcLoc, CXXScopeSpec &SS,
                          SourceLocation IdentLoc,
                          IdentifierInfo *NamespcName,
                          const ParsedAttributesView &AttrList);

void PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir);

Decl *ActOnNamespaceAliasDef(Scope *CurScope,
                             SourceLocation NamespaceLoc,
                             SourceLocation AliasLoc,
                             IdentifierInfo *Alias,
                             CXXScopeSpec &SS,
                             SourceLocation IdentLoc,
                             IdentifierInfo *Ident);

void FilterUsingLookup(Scope *S, LookupResult &lookup);
void HideUsingShadowDecl(Scope *S, UsingShadowDecl *Shadow);
bool CheckUsingShadowDecl(BaseUsingDecl *BUD, NamedDecl *Target,
                          const LookupResult &PreviousDecls,
                          UsingShadowDecl *&PrevShadow);
UsingShadowDecl *BuildUsingShadowDecl(Scope *S, BaseUsingDecl *BUD,
                                      NamedDecl *Target,
                                      UsingShadowDecl *PrevDecl);

bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
                                 bool HasTypenameKeyword,
                                 const CXXScopeSpec &SS,
                                 SourceLocation NameLoc,
                                 const LookupResult &Previous);
bool CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
                             const CXXScopeSpec &SS,
                             const DeclarationNameInfo &NameInfo,
                             SourceLocation NameLoc,
                             const LookupResult *R = nullptr,
                             const UsingDecl *UD = nullptr);

NamedDecl *BuildUsingDeclaration(
    Scope *S, AccessSpecifier AS, SourceLocation UsingLoc,
    bool HasTypenameKeyword, SourceLocation TypenameLoc, CXXScopeSpec &SS,
    DeclarationNameInfo NameInfo, SourceLocation EllipsisLoc,
    const ParsedAttributesView &AttrList, bool IsInstantiation,
    bool IsUsingIfExists);
NamedDecl *BuildUsingEnumDeclaration(Scope *S, AccessSpecifier AS,
                                     SourceLocation UsingLoc,
                                     SourceLocation EnumLoc,
                                     SourceLocation NameLoc, EnumDecl *ED);
NamedDecl *BuildUsingPackDecl(NamedDecl *InstantiatedFrom,
                              ArrayRef<NamedDecl *> Expansions);

bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);

/// Given a derived-class using shadow declaration for a constructor and the
/// correspnding base class constructor, find or create the implicit
/// synthesized derived class constructor to use for this initialization.
CXXConstructorDecl *
findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
                          ConstructorUsingShadowDecl *DerivedShadow);

Decl *ActOnUsingDeclaration(Scope *CurScope, AccessSpecifier AS,
                            SourceLocation UsingLoc,
                            SourceLocation TypenameLoc, CXXScopeSpec &SS,
                            UnqualifiedId &Name, SourceLocation EllipsisLoc,
                            const ParsedAttributesView &AttrList);
Decl *ActOnUsingEnumDeclaration(Scope *CurScope, AccessSpecifier AS,
                                SourceLocation UsingLoc,
                                SourceLocation EnumLoc, const DeclSpec &);
Decl *ActOnAliasDeclaration(Scope *CurScope, AccessSpecifier AS,
                            MultiTemplateParamsArg TemplateParams,
                            SourceLocation UsingLoc, UnqualifiedId &Name,
                            const ParsedAttributesView &AttrList,
                            TypeResult Type, Decl *DeclFromDeclSpec);

/// BuildCXXConstructExpr - Creates a complete call to a constructor,
/// including handling of its default argument expressions.
///
/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

/// Build a CXXConstructExpr whose constructor has already been resolved if
/// it denotes an inherited constructor.
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
// the constructor can be elidable?
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs, bool HadMultipleCandidates,
                      bool IsListInitialization,
                      bool IsStdInitListInitialization, bool RequiresZeroInit,
                      unsigned ConstructKind, SourceRange ParenRange);

ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);


/// Instantiate or parse a C++ default argument expression as necessary.
/// Return true on error.
bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
                            ParmVarDecl *Param);

/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
/// the default expr if needed.
ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc,
                                  FunctionDecl *FD,
                                  ParmVarDecl *Param);

/// FinalizeVarWithDestructor - Prepare for calling destructor on the
/// constructed variable.
void FinalizeVarWithDestructor(VarDecl *VD, const RecordType *DeclInitType);

/// Helper class that collects exception specifications for
/// implicitly-declared special member functions.
class ImplicitExceptionSpecification {
  // Pointer to allow copying
  Sema *Self;
  // We order exception specifications thus:
  // noexcept is the most restrictive, but is only used in C++11.
  // throw() comes next.
  // Then a throw(collected exceptions)
  // Finally no specification, which is expressed as noexcept(false).
  // throw(...) is used instead if any called function uses it.
  ExceptionSpecificationType ComputedEST;
  llvm::SmallPtrSet<CanQualType, 4> ExceptionsSeen;
  SmallVector<QualType, 4> Exceptions;

  void ClearExceptions() {
    ExceptionsSeen.clear();
    Exceptions.clear();
  }

public:
  explicit ImplicitExceptionSpecification(Sema &Self)
    : Self(&Self), ComputedEST(EST_BasicNoexcept) {
    if (!Self.getLangOpts().CPlusPlus11)
      ComputedEST = EST_DynamicNone;
  }

  /// Get the computed exception specification type.
  ExceptionSpecificationType getExceptionSpecType() const {
    assert(!isComputedNoexcept(ComputedEST) &&((void)0)
           "noexcept(expr) should not be a possible result")((void)0);
    return ComputedEST;
  }

  /// The number of exceptions in the exception specification.
  unsigned size() const { return Exceptions.size(); }

  /// The set of exceptions in the exception specification.
  const QualType *data() const { return Exceptions.data(); }

  /// Integrate another called method into the collected data.
  void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);

  /// Integrate an invoked expression into the collected data.
  void CalledExpr(Expr *E) { CalledStmt(E); }

  /// Integrate an invoked statement into the collected data.
  void CalledStmt(Stmt *S);

  /// Overwrite an EPI's exception specification with this
  /// computed exception specification.
  FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
    FunctionProtoType::ExceptionSpecInfo ESI;
    ESI.Type = getExceptionSpecType();
    if (ESI.Type == EST_Dynamic) {
      ESI.Exceptions = Exceptions;
    } else if (ESI.Type == EST_None) {
      /// C++11 [except.spec]p14:
      ///   The exception-specification is noexcept(false) if the set of
      ///   potential exceptions of the special member function contains "any"
      ESI.Type = EST_NoexceptFalse;
      ESI.NoexceptExpr = Self->ActOnCXXBoolLiteral(SourceLocation(),
                                                   tok::kw_false).get();
    }
    return ESI;
  }
};

/// Evaluate the implicit exception specification for a defaulted
/// special member function.
void EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD);

/// Check the given noexcept-specifier, convert its expression, and compute
/// the appropriate ExceptionSpecificationType.
ExprResult ActOnNoexceptSpec(SourceLocation NoexceptLoc, Expr *NoexceptExpr,
                             ExceptionSpecificationType &EST);

/// Check the given exception-specification and update the
/// exception specification information with the results.
void checkExceptionSpecification(bool IsTopLevel,
                                 ExceptionSpecificationType EST,
                                 ArrayRef<ParsedType> DynamicExceptions,
                                 ArrayRef<SourceRange> DynamicExceptionRanges,
                                 Expr *NoexceptExpr,
                                 SmallVectorImpl<QualType> &Exceptions,
                                 FunctionProtoType::ExceptionSpecInfo &ESI);

/// Determine if we're in a case where we need to (incorrectly) eagerly
/// parse an exception specification to work around a libstdc++ bug.
bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);

/// Add an exception-specification to the given member function
/// (or member function template). The exception-specification was parsed
/// after the method itself was declared.
void actOnDelayedExceptionSpecification(Decl *Method,
       ExceptionSpecificationType EST,
       SourceRange SpecificationRange,
       ArrayRef<ParsedType> DynamicExceptions,
       ArrayRef<SourceRange> DynamicExceptionRanges,
       Expr *NoexceptExpr);

class InheritedConstructorInfo;

/// Determine if a special member function should have a deleted
/// definition when it is defaulted.
bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMember CSM,
                               InheritedConstructorInfo *ICI = nullptr,
                               bool Diagnose = false);

/// Produce notes explaining why a defaulted function was defined as deleted.
void DiagnoseDeletedDefaultedFunction(FunctionDecl *FD);

/// Declare the implicit default constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// default constructor will be added.
///
/// \returns The implicitly-declared default constructor.
CXXConstructorDecl *DeclareImplicitDefaultConstructor(
                                                   CXXRecordDecl *ClassDecl);

/// DefineImplicitDefaultConstructor - Checks for feasibility of
/// defining this constructor as the default constructor.
void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
                                      CXXConstructorDecl *Constructor);

/// Declare the implicit destructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// destructor will be added.
///
/// \returns The implicitly-declared destructor.
CXXDestructorDecl *DeclareImplicitDestructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitDestructor - Checks for feasibility of
/// defining this destructor as the default destructor.
void DefineImplicitDestructor(SourceLocation CurrentLocation,
                              CXXDestructorDecl *Destructor);

/// Build an exception spec for destructors that don't have one.
///
/// C++11 says that user-defined destructors with no exception spec get one
/// that looks as if the destructor was implicitly declared.
void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);

/// Define the specified inheriting constructor.
void DefineInheritingConstructor(SourceLocation UseLoc,
                                 CXXConstructorDecl *Constructor);

/// Declare the implicit copy constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy constructor will be added.
///
/// \returns The implicitly-declared copy constructor.
CXXConstructorDecl *DeclareImplicitCopyConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitCopyConstructor - Checks for feasibility of
/// defining this constructor as the copy constructor.
void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit move constructor for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move constructor will be added.
///
/// \returns The implicitly-declared move constructor, or NULL if it wasn't
/// declared.
CXXConstructorDecl *DeclareImplicitMoveConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitMoveConstructor - Checks for feasibility of
/// defining this constructor as the move constructor.
void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit copy assignment operator for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy assignment operator will be added.
///
/// \returns The implicitly-declared copy assignment operator.
CXXMethodDecl *DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared copy assignment operator.
void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Declare the implicit move assignment operator for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move assignment operator will be added.
///
/// \returns The implicitly-declared move assignment operator, or NULL if it
/// wasn't declared.
CXXMethodDecl *DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared move assignment operator.
void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Force the declaration of any implicitly-declared members of this
/// class.
void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);

/// Check a completed declaration of an implicit special member.
void CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD);

/// Determine whether the given function is an implicitly-deleted
/// special member function.
bool isImplicitlyDeleted(FunctionDecl *FD);

/// Check whether 'this' shows up in the type of a static member
/// function after the (naturally empty) cv-qualifier-seq would be.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);

/// Whether this' shows up in the exception specification of a static
/// member function.
bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);

/// Check whether 'this' shows up in the attributes of the given
/// static member function.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);

/// MaybeBindToTemporary - If the passed in expression has a record type with
/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
/// it simply returns the passed in expression.
ExprResult MaybeBindToTemporary(Expr *E);

/// Wrap the expression in a ConstantExpr if it is a potential immediate
/// invocation.
ExprResult CheckForImmediateInvocation(ExprResult E, FunctionDecl *Decl);

bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
                             QualType DeclInitType, MultiExprArg ArgsPtr,
                             SourceLocation Loc,
                             SmallVectorImpl<Expr *> &ConvertedArgs,
                             bool AllowExplicit = false,
                             bool IsListInitialization = false);

ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
                                        SourceLocation NameLoc,
                                        IdentifierInfo &Name);

ParsedType getConstructorName(IdentifierInfo &II, SourceLocation NameLoc,
                              Scope *S, CXXScopeSpec &SS,
                              bool EnteringContext);
ParsedType getDestructorName(SourceLocation TildeLoc,
                             IdentifierInfo &II, SourceLocation NameLoc,
                             Scope *S, CXXScopeSpec &SS,
                             ParsedType ObjectType,
                             bool EnteringContext);

ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
                                        ParsedType ObjectType);

// Checks that reinterpret casts don't have undefined behavior.
void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
                                    bool IsDereference, SourceRange Range);

// Checks that the vector type should be initialized from a scalar
// by splatting the value rather than populating a single element.
// This is the case for AltiVecVector types as well as with
// AltiVecPixel and AltiVecBool when -faltivec-src-compat=xl is specified.
bool ShouldSplatAltivecScalarInCast(const VectorType *VecTy);

/// ActOnCXXNamedCast - Parse
/// {dynamic,static,reinterpret,const,addrspace}_cast's.
ExprResult ActOnCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             SourceLocation LAngleBracketLoc,
                             Declarator &D,
                             SourceLocation RAngleBracketLoc,
                             SourceLocation LParenLoc,
                             Expr *E,
                             SourceLocation RParenLoc);

ExprResult BuildCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             TypeSourceInfo *Ty,
                             Expr *E,
                             SourceRange AngleBrackets,
                             SourceRange Parens);

ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
                                   ExprResult Operand,
                                   SourceLocation RParenLoc);

ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
                                   Expr *Operand, SourceLocation RParenLoc);

ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXTypeid - Parse typeid( something ).
ExprResult ActOnCXXTypeid(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXUuidof - Parse __uuidof( something ).
ExprResult ActOnCXXUuidof(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

/// Handle a C++1z fold-expression: ( expr op ... op expr ).
ExprResult ActOnCXXFoldExpr(Scope *S, SourceLocation LParenLoc, Expr *LHS,
                            tok::TokenKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc);
ExprResult BuildCXXFoldExpr(UnresolvedLookupExpr *Callee,
                            SourceLocation LParenLoc, Expr *LHS,
                            BinaryOperatorKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc,
                            Optional<unsigned> NumExpansions);
ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
                                 BinaryOperatorKind Operator);

//// ActOnCXXThis -  Parse 'this' pointer.
ExprResult ActOnCXXThis(SourceLocation loc);

/// Build a CXXThisExpr and mark it referenced in the current context.
Expr *BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool IsImplicit);
void MarkThisReferenced(CXXThisExpr *This);

/// Try to retrieve the type of the 'this' pointer.
///
/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
QualType getCurrentThisType();

/// When non-NULL, the C++ 'this' expression is allowed despite the
/// current context not being a non-static member function. In such cases,
/// this provides the type used for 'this'.
QualType CXXThisTypeOverride;

/// RAII object used to temporarily allow the C++ 'this' expression
/// to be used, with the given qualifiers on the current class type.
class CXXThisScopeRAII {
  Sema &S;
  QualType OldCXXThisTypeOverride;
  bool Enabled;

public:
  /// Introduce a new scope where 'this' may be allowed (when enabled),
  /// using the given declaration (which is either a class template or a
  /// class) along with the given qualifiers.
  /// along with the qualifiers placed on '*this'.
  CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
                   bool Enabled = true);

  ~CXXThisScopeRAII();
};

/// Make sure the value of 'this' is actually available in the current
/// context, if it is a potentially evaluated context.
///
/// \param Loc The location at which the capture of 'this' occurs.
///
/// \param Explicit Whether 'this' is explicitly captured in a lambda
/// capture list.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// 'this' that may or may not be used in certain specializations of
/// a nested generic lambda (depending on whether the name resolves to
/// a non-static member function or a static function).
/// \return returns 'true' if failed, 'false' if success.
bool CheckCXXThisCapture(SourceLocation Loc, bool Explicit = false,
    bool BuildAndDiagnose = true,
    const unsigned *const FunctionScopeIndexToStopAt = nullptr,
    bool ByCopy = false);

/// Determine whether the given type is the type of *this that is used
/// outside of the body of a member function for a type that is currently
/// being defined.
bool isThisOutsideMemberFunctionBody(QualType BaseType);

/// ActOnCXXBoolLiteral - Parse {true,false} literals.
ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);


/// ActOnObjCBoolLiteral - Parse {__objc_yes,__objc_no} literals.
ExprResult ActOnObjCBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);

ExprResult
ActOnObjCAvailabilityCheckExpr(llvm::ArrayRef<AvailabilitySpec> AvailSpecs,
                               SourceLocation AtLoc, SourceLocation RParen);

/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);

//// ActOnCXXThrow -  Parse throw expressions.
ExprResult ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *expr);
ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
                         bool IsThrownVarInScope);
bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);

/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
                                     SourceLocation LParenOrBraceLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenOrBraceLoc,
                                     bool ListInitialization);

ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
                                     SourceLocation LParenLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenLoc,
                                     bool ListInitialization);

/// ActOnCXXNew - Parsed a C++ 'new' expression.
ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens, Declarator &D,
                       Expr *Initializer);
ExprResult BuildCXXNew(SourceRange Range, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens,
                       QualType AllocType,
                       TypeSourceInfo *AllocTypeInfo,
                       Optional<Expr *> ArraySize,
                       SourceRange DirectInitRange,
                       Expr *Initializer);

/// Determine whether \p FD is an aligned allocation or deallocation
/// function that is unavailable.
bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;

/// Produce diagnostics if \p FD is an aligned allocation or deallocation
/// function that is unavailable.
void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
                                          SourceLocation Loc);

bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                        SourceRange R);

/// The scope in which to find allocation functions.
enum AllocationFunctionScope {
  /// Only look for allocation functions in the global scope.
  AFS_Global,
  /// Only look for allocation functions in the scope of the
  /// allocated class.
  AFS_Class,
  /// Look for allocation functions in both the global scope
  /// and in the scope of the allocated class.
  AFS_Both
};

/// Finds the overloads of operator new and delete that are appropriate
/// for the allocation.
bool FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
                             AllocationFunctionScope NewScope,
                             AllocationFunctionScope DeleteScope,
                             QualType AllocType, bool IsArray,
                             bool &PassAlignment, MultiExprArg PlaceArgs,
                             FunctionDecl *&OperatorNew,
                             FunctionDecl *&OperatorDelete,
                             bool Diagnose = true);
void DeclareGlobalNewDelete();
void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
                                     ArrayRef<QualType> Params);

bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
                              DeclarationName Name, FunctionDecl* &Operator,
                              bool Diagnose = true);
FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
                                            bool CanProvideSize,
                                            bool Overaligned,
                                            DeclarationName Name);
FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
                                                    CXXRecordDecl *RD);

/// ActOnCXXDelete - Parsed a C++ 'delete' expression
ExprResult ActOnCXXDelete(SourceLocation StartLoc,
                          bool UseGlobal, bool ArrayForm,
                          Expr *Operand);
void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
                          bool IsDelete, bool CallCanBeVirtual,
                          bool WarnOnNonAbstractTypes,
                          SourceLocation DtorLoc);

ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
                             Expr *Operand, SourceLocation RParen);
ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
                                SourceLocation RParen);

/// Parsed one of the type trait support pseudo-functions.
ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<ParsedType> Args,
                          SourceLocation RParenLoc);
ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<TypeSourceInfo *> Args,
                          SourceLocation RParenLoc);

/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
/// pseudo-functions.
ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               ParsedType LhsTy,
                               Expr *DimExpr,
                               SourceLocation RParen);

ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               TypeSourceInfo *TSInfo,
                               Expr *DimExpr,
                               SourceLocation RParen);

/// ActOnExpressionTrait - Parsed one of the unary type trait support
/// pseudo-functions.
ExprResult ActOnExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult BuildExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult ActOnStartCXXMemberReference(Scope *S,
                                        Expr *Base,
                                        SourceLocation OpLoc,
                                        tok::TokenKind OpKind,
                                        ParsedType &ObjectType,
                                        bool &MayBePseudoDestructor);

ExprResult BuildPseudoDestructorExpr(Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     const CXXScopeSpec &SS,
                                     TypeSourceInfo *ScopeType,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                   PseudoDestructorTypeStorage DestroyedType);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     CXXScopeSpec &SS,
                                     UnqualifiedId &FirstTypeName,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                     UnqualifiedId &SecondTypeName);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     SourceLocation TildeLoc,
                                     const DeclSpec& DS);

/// MaybeCreateExprWithCleanups - If the current full-expression
/// requires any cleanups, surround it with a ExprWithCleanups node.
/// Otherwise, just returns the passed-in expression.
Expr *MaybeCreateExprWithCleanups(Expr *SubExpr);
Stmt *MaybeCreateStmtWithCleanups(Stmt *SubStmt);
ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);

MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
                               bool BoundToLvalueReference);

ExprResult ActOnFinishFullExpr(Expr *Expr, bool DiscardedValue) {
  return ActOnFinishFullExpr(
      Expr, Expr ? Expr->getExprLoc() : SourceLocation(), DiscardedValue);
}
ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
                               bool DiscardedValue, bool IsConstexpr = false);
StmtResult ActOnFinishFullStmt(Stmt *Stmt);

// Marks SS invalid if it represents an incomplete type.
bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);
// Complete an enum decl, maybe without a scope spec.
bool RequireCompleteEnumDecl(EnumDecl *D, SourceLocation L,
                             CXXScopeSpec *SS = nullptr);

DeclContext *computeDeclContext(QualType T);
DeclContext *computeDeclContext(const CXXScopeSpec &SS,
                                bool EnteringContext = false);
bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier *NNS);

/// The parser has parsed a global nested-name-specifier '::'.
///
/// \param CCLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);

/// The parser has parsed a '__super' nested-name-specifier.
///
/// \param SuperLoc The location of the '__super' keyword.
///
/// \param ColonColonLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
                              SourceLocation ColonColonLoc, CXXScopeSpec &SS);

bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
                                     bool *CanCorrect = nullptr);
NamedDecl *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);

/// Keeps information about an identifier in a nested-name-spec.
///
struct NestedNameSpecInfo {
  /// The type of the object, if we're parsing nested-name-specifier in
  /// a member access expression.
  ParsedType ObjectType;

  /// The identifier preceding the '::'.
  IdentifierInfo *Identifier;

  /// The location of the identifier.
  SourceLocation IdentifierLoc;

  /// The location of the '::'.
  SourceLocation CCLoc;

  /// Creates info object for the most typical case.
  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
           SourceLocation ColonColonLoc, ParsedType ObjectType = ParsedType())
    : ObjectType(ObjectType), Identifier(II), IdentifierLoc(IdLoc),
      CCLoc(ColonColonLoc) {
  }

  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
                     SourceLocation ColonColonLoc, QualType ObjectType)
    : ObjectType(ParsedType::make(ObjectType)), Identifier(II),
      IdentifierLoc(IdLoc), CCLoc(ColonColonLoc) {
  }
};

bool isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
                                  NestedNameSpecInfo &IdInfo);

bool BuildCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 NamedDecl *ScopeLookupResult,
                                 bool ErrorRecoveryLookup,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

/// The parser has parsed a nested-name-specifier 'identifier::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param IdInfo Parser information about an identifier in the
/// nested-name-spec.
///
/// \param EnteringContext Whether we're entering the context nominated by
/// this nested-name-specifier.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param ErrorRecoveryLookup If true, then this method is called to improve
/// error recovery. In this case do not emit error message.
///
/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
/// are allowed.  The bool value pointed by this parameter is set to 'true'
/// if the identifier is treated as if it was followed by ':', not '::'.
///
/// \param OnlyNamespace If true, only considers namespaces in lookup.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 bool ErrorRecoveryLookup = false,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

ExprResult ActOnDecltypeExpression(Expr *E);

bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
                                         const DeclSpec &DS,
                                         SourceLocation ColonColonLoc);

bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
                               NestedNameSpecInfo &IdInfo,
                               bool EnteringContext);

/// The parser has parsed a nested-name-specifier
/// 'template[opt] template-name < template-args >::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param TemplateKWLoc the location of the 'template' keyword, if any.
/// \param TemplateName the template name.
/// \param TemplateNameLoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
/// \param CCLoc The location of the '::'.
///
/// \param EnteringContext Whether we're entering the context of the
/// nested-name-specifier.
///
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 TemplateTy TemplateName,
                                 SourceLocation TemplateNameLoc,
                                 SourceLocation LAngleLoc,
                                 ASTTemplateArgsPtr TemplateArgs,
                                 SourceLocation RAngleLoc,
                                 SourceLocation CCLoc,
                                 bool EnteringContext);

/// Given a C++ nested-name-specifier, produce an annotation value
/// that the parser can use later to reconstruct the given
/// nested-name-specifier.
///
/// \param SS A nested-name-specifier.
///
/// \returns A pointer containing all of the information in the
/// nested-name-specifier \p SS.
void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);

/// Given an annotation pointer for a nested-name-specifier, restore
/// the nested-name-specifier structure.
///
/// \param Annotation The annotation pointer, produced by
/// \c SaveNestedNameSpecifierAnnotation().
///
/// \param AnnotationRange The source range corresponding to the annotation.
///
/// \param SS The nested-name-specifier that will be updated with the contents
/// of the annotation pointer.
void RestoreNestedNameSpecifierAnnotation(void *Annotation,
                                          SourceRange AnnotationRange,
                                          CXXScopeSpec &SS);

bool ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
/// scope or nested-name-specifier) is parsed, part of a declarator-id.
/// After this method is called, according to [C++ 3.4.3p3], names should be
/// looked up in the declarator-id's scope, until the declarator is parsed and
/// ActOnCXXExitDeclaratorScope is called.
/// The 'SS' should be a non-empty valid CXXScopeSpec.
bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);

/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
/// Used to indicate that names should revert to being looked up in the
/// defining scope.
void ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
/// initializer for the declaration 'Dcl'.
/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
/// static data member of class X, names should be looked up in the scope of
/// class X.
void ActOnCXXEnterDeclInitializer(Scope *S, Decl *Dcl);

/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
/// initializer for the declaration 'Dcl'.
void ActOnCXXExitDeclInitializer(Scope *S, Decl *Dcl);

/// Create a new lambda closure type.
CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
                                       TypeSourceInfo *Info,
                                       bool KnownDependent,
                                       LambdaCaptureDefault CaptureDefault);

/// Start the definition of a lambda expression.
CXXMethodDecl *startLambdaDefinition(CXXRecordDecl *Class,
                                     SourceRange IntroducerRange,
                                     TypeSourceInfo *MethodType,
                                     SourceLocation EndLoc,
                                     ArrayRef<ParmVarDecl *> Params,
                                     ConstexprSpecKind ConstexprKind,
                                     Expr *TrailingRequiresClause);

/// Number lambda for linkage purposes if necessary.
void handleLambdaNumbering(
    CXXRecordDecl *Class, CXXMethodDecl *Method,
    Optional<std::tuple<bool, unsigned, unsigned, Decl *>> Mangling = None);

/// Endow the lambda scope info with the relevant properties.
void buildLambdaScope(sema::LambdaScopeInfo *LSI,
                      CXXMethodDecl *CallOperator,
                      SourceRange IntroducerRange,
                      LambdaCaptureDefault CaptureDefault,
                      SourceLocation CaptureDefaultLoc,
                      bool ExplicitParams,
                      bool ExplicitResultType,
                      bool Mutable);

/// Perform initialization analysis of the init-capture and perform
/// any implicit conversions such as an lvalue-to-rvalue conversion if
/// not being used to initialize a reference.
ParsedType actOnLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    IdentifierInfo *Id, LambdaCaptureInitKind InitKind, Expr *&Init) {
  return ParsedType::make(buildLambdaInitCaptureInitialization(
      Loc, ByRef, EllipsisLoc, None, Id,
      InitKind != LambdaCaptureInitKind::CopyInit, Init));
}
QualType buildLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    Optional<unsigned> NumExpansions, IdentifierInfo *Id, bool DirectInit,
    Expr *&Init);

/// Create a dummy variable within the declcontext of the lambda's
///  call operator, for name lookup purposes for a lambda init capture.
///
///  CodeGen handles emission of lambda captures, ignoring these dummy
///  variables appropriately.
VarDecl *createLambdaInitCaptureVarDecl(SourceLocation Loc,
                                        QualType InitCaptureType,
                                        SourceLocation EllipsisLoc,
                                        IdentifierInfo *Id,
                                        unsigned InitStyle, Expr *Init);

/// Add an init-capture to a lambda scope.
void addInitCapture(sema::LambdaScopeInfo *LSI, VarDecl *Var);

/// Note that we have finished the explicit captures for the
/// given lambda.
void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);

/// \brief This is called after parsing the explicit template parameter list
/// on a lambda (if it exists) in C++2a.
void ActOnLambdaExplicitTemplateParameterList(SourceLocation LAngleLoc,
                                              ArrayRef<NamedDecl *> TParams,
                                              SourceLocation RAngleLoc,
                                              ExprResult RequiresClause);

/// Introduce the lambda parameters into scope.
void addLambdaParameters(
    ArrayRef<LambdaIntroducer::LambdaCapture> Captures,
    CXXMethodDecl *CallOperator, Scope *CurScope);

/// Deduce a block or lambda's return type based on the return
/// statements present in the body.
void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);

/// ActOnStartOfLambdaDefinition - This is called just before we start
/// parsing the body of a lambda; it analyzes the explicit captures and
/// arguments, and sets up various data-structures for the body of the
/// lambda.
void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
                                  Declarator &ParamInfo, Scope *CurScope);

/// ActOnLambdaError - If there is an error parsing a lambda, this callback
/// is invoked to pop the information about the lambda.
void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
                      bool IsInstantiation = false);

/// ActOnLambdaExpr - This is called when the body of a lambda expression
/// was successfully completed.
ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body,
                           Scope *CurScope);

/// Does copying/destroying the captured variable have side effects?
bool CaptureHasSideEffects(const sema::Capture &From);

/// Diagnose if an explicit lambda capture is unused. Returns true if a
/// diagnostic is emitted.
bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
                                 const sema::Capture &From);

/// Build a FieldDecl suitable to hold the given capture.
FieldDecl *BuildCaptureField(RecordDecl *RD, const sema::Capture &Capture);

/// Initialize the given capture with a suitable expression.
ExprResult BuildCaptureInit(const sema::Capture &Capture,
                            SourceLocation ImplicitCaptureLoc,
                            bool IsOpenMPMapping = false);

/// Complete a lambda-expression having processed and attached the
/// lambda body.
ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                           sema::LambdaScopeInfo *LSI);

/// Get the return type to use for a lambda's conversion function(s) to
/// function pointer type, given the type of the call operator.
QualType
getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType,
                                      CallingConv CC);

/// Define the "body" of the conversion from a lambda object to a
/// function pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToFunctionPointerConversion(
       SourceLocation CurrentLoc, CXXConversionDecl *Conv);

/// Define the "body" of the conversion from a lambda object to a
/// block pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
                                                  CXXConversionDecl *Conv);

ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
                                         SourceLocation ConvLocation,
                                         CXXConversionDecl *Conv,
                                         Expr *Src);

/// Check whether the given expression is a valid constraint expression.
/// A diagnostic is emitted if it is not, false is returned, and
/// PossibleNonPrimary will be set to true if the failure might be due to a
/// non-primary expression being used as an atomic constraint.
bool CheckConstraintExpression(const Expr *CE, Token NextToken = Token(),
                               bool *PossibleNonPrimary = nullptr,
                               bool IsTrailingRequiresClause = false);

6803private:
/// Caches pairs of template-like decls whose associated constraints were
/// checked for subsumption and whether or not the first's constraints did in
/// fact subsume the second's.
llvm::DenseMap<std::pair<NamedDecl *, NamedDecl *>, bool> SubsumptionCache;
/// Caches the normalized associated constraints of declarations (concepts or
/// constrained declarations). If an error occurred while normalizing the
/// associated constraints of the template or concept, nullptr will be cached
/// here.
llvm::DenseMap<NamedDecl *, NormalizedConstraint *>
    NormalizationCache;

llvm::ContextualFoldingSet<ConstraintSatisfaction, const ASTContext &>
    SatisfactionCache;

6818public:
const NormalizedConstraint *
getNormalizedAssociatedConstraints(
    NamedDecl *ConstrainedDecl, ArrayRef<const Expr *> AssociatedConstraints);

/// \brief Check whether the given declaration's associated constraints are
/// at least as constrained than another declaration's according to the
/// partial ordering of constraints.
///
/// \param Result If no error occurred, receives the result of true if D1 is
/// at least constrained than D2, and false otherwise.
///
/// \returns true if an error occurred, false otherwise.
bool IsAtLeastAsConstrained(NamedDecl *D1, ArrayRef<const Expr *> AC1,
                            NamedDecl *D2, ArrayRef<const Expr *> AC2,
                            bool &Result);

/// If D1 was not at least as constrained as D2, but would've been if a pair
/// of atomic constraints involved had been declared in a concept and not
/// repeated in two separate places in code.
/// \returns true if such a diagnostic was emitted, false otherwise.
bool MaybeEmitAmbiguousAtomicConstraintsDiagnostic(NamedDecl *D1,
    ArrayRef<const Expr *> AC1, NamedDecl *D2, ArrayRef<const Expr *> AC2);

/// \brief Check whether the given list of constraint expressions are
/// satisfied (as if in a 'conjunction') given template arguments.
/// \param Template the template-like entity that triggered the constraints
/// check (either a concept or a constrained entity).
/// \param ConstraintExprs a list of constraint expressions, treated as if
/// they were 'AND'ed together.
/// \param TemplateArgs the list of template arguments to substitute into the
/// constraint expression.
/// \param TemplateIDRange The source range of the template id that
/// caused the constraints check.
/// \param Satisfaction if true is returned, will contain details of the
/// satisfaction, with enough information to diagnose an unsatisfied
/// expression.
/// \returns true if an error occurred and satisfaction could not be checked,
/// false otherwise.
bool CheckConstraintSatisfaction(
    const NamedDecl *Template, ArrayRef<const Expr *> ConstraintExprs,
    ArrayRef<TemplateArgument> TemplateArgs,
    SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction);

/// \brief Check whether the given non-dependent constraint expression is
/// satisfied. Returns false and updates Satisfaction with the satisfaction
/// verdict if successful, emits a diagnostic and returns true if an error
/// occured and satisfaction could not be determined.
///
/// \returns true if an error occurred, false otherwise.
bool CheckConstraintSatisfaction(const Expr *ConstraintExpr,
                                 ConstraintSatisfaction &Satisfaction);

/// Check whether the given function decl's trailing requires clause is
/// satisfied, if any. Returns false and updates Satisfaction with the
/// satisfaction verdict if successful, emits a diagnostic and returns true if
/// an error occured and satisfaction could not be determined.
///
/// \returns true if an error occurred, false otherwise.
bool CheckFunctionConstraints(const FunctionDecl *FD,
                              ConstraintSatisfaction &Satisfaction,
                              SourceLocation UsageLoc = SourceLocation());


/// \brief Ensure that the given template arguments satisfy the constraints
/// associated with the given template, emitting a diagnostic if they do not.
///
/// \param Template The template to which the template arguments are being
/// provided.
///
/// \param TemplateArgs The converted, canonicalized template arguments.
///
/// \param TemplateIDRange The source range of the template id that
/// caused the constraints check.
///
/// \returns true if the constrains are not satisfied or could not be checked
/// for satisfaction, false if the constraints are satisfied.
bool EnsureTemplateArgumentListConstraints(TemplateDecl *Template,
                                     ArrayRef<TemplateArgument> TemplateArgs,
                                           SourceRange TemplateIDRange);

/// \brief Emit diagnostics explaining why a constraint expression was deemed
/// unsatisfied.
/// \param First whether this is the first time an unsatisfied constraint is
/// diagnosed for this error.
void
DiagnoseUnsatisfiedConstraint(const ConstraintSatisfaction &Satisfaction,
                              bool First = true);

/// \brief Emit diagnostics explaining why a constraint expression was deemed
/// unsatisfied.
void
DiagnoseUnsatisfiedConstraint(const ASTConstraintSatisfaction &Satisfaction,
                              bool First = true);

// ParseObjCStringLiteral - Parse Objective-C string literals.
ExprResult ParseObjCStringLiteral(SourceLocation *AtLocs,
                                  ArrayRef<Expr *> Strings);

ExprResult BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S);

/// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
/// numeric literal expression. Type of the expression will be "NSNumber *"
/// or "id" if NSNumber is unavailable.
ExprResult BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number);
ExprResult ActOnObjCBoolLiteral(SourceLocation AtLoc, SourceLocation ValueLoc,
                                bool Value);
ExprResult BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements);

/// BuildObjCBoxedExpr - builds an ObjCBoxedExpr AST node for the
/// '@' prefixed parenthesized expression. The type of the expression will
/// either be "NSNumber *", "NSString *" or "NSValue *" depending on the type
/// of ValueType, which is allowed to be a built-in numeric type, "char *",
/// "const char *" or C structure with attribute 'objc_boxable'.
ExprResult BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr);

ExprResult BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
                                        Expr *IndexExpr,
                                        ObjCMethodDecl *getterMethod,
                                        ObjCMethodDecl *setterMethod);

ExprResult BuildObjCDictionaryLiteral(SourceRange SR,
                             MutableArrayRef<ObjCDictionaryElement> Elements);

ExprResult BuildObjCEncodeExpression(SourceLocation AtLoc,
                                TypeSourceInfo *EncodedTypeInfo,
                                SourceLocation RParenLoc);
ExprResult BuildCXXMemberCallExpr(Expr *Exp, NamedDecl *FoundDecl,
                                  CXXConversionDecl *Method,
                                  bool HadMultipleCandidates);

ExprResult ParseObjCEncodeExpression(SourceLocation AtLoc,
                                     SourceLocation EncodeLoc,
                                     SourceLocation LParenLoc,
                                     ParsedType Ty,
                                     SourceLocation RParenLoc);

/// ParseObjCSelectorExpression - Build selector expression for \@selector
ExprResult ParseObjCSelectorExpression(Selector Sel,
                                       SourceLocation AtLoc,
                                       SourceLocation SelLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation RParenLoc,
                                       bool WarnMultipleSelectors);

/// ParseObjCProtocolExpression - Build protocol expression for \@protocol
ExprResult ParseObjCProtocolExpression(IdentifierInfo * ProtocolName,
                                       SourceLocation AtLoc,
                                       SourceLocation ProtoLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation ProtoIdLoc,
                                       SourceLocation RParenLoc);

//===--------------------------------------------------------------------===//
// C++ Declarations
//
Decl *ActOnStartLinkageSpecification(Scope *S,
                                     SourceLocation ExternLoc,
                                     Expr *LangStr,
                                     SourceLocation LBraceLoc);
Decl *ActOnFinishLinkageSpecification(Scope *S,
                                      Decl *LinkageSpec,
                                      SourceLocation RBraceLoc);


//===--------------------------------------------------------------------===//
// C++ Classes
//
CXXRecordDecl *getCurrentClass(Scope *S, const CXXScopeSpec *SS);
bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
                        const CXXScopeSpec *SS = nullptr);
bool isCurrentClassNameTypo(IdentifierInfo *&II, const CXXScopeSpec *SS);

bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
                          SourceLocation ColonLoc,
                          const ParsedAttributesView &Attrs);

NamedDecl *ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS,
                               Declarator &D,
                               MultiTemplateParamsArg TemplateParameterLists,
                               Expr *BitfieldWidth, const VirtSpecifiers &VS,
                               InClassInitStyle InitStyle);

void ActOnStartCXXInClassMemberInitializer();
void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
                                            SourceLocation EqualLoc,
                                            Expr *Init);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  SourceLocation LParenLoc,
                                  ArrayRef<Expr *> Args,
                                  SourceLocation RParenLoc,
                                  SourceLocation EllipsisLoc);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *InitList,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *Init,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemberInitializer(ValueDecl *Member,
                                     Expr *Init,
                                     SourceLocation IdLoc);

MemInitResult BuildBaseInitializer(QualType BaseType,
                                   TypeSourceInfo *BaseTInfo,
                                   Expr *Init,
                                   CXXRecordDecl *ClassDecl,
                                   SourceLocation EllipsisLoc);

MemInitResult BuildDelegatingInitializer(TypeSourceInfo *TInfo,
                                         Expr *Init,
                                         CXXRecordDecl *ClassDecl);

bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
                              CXXCtorInitializer *Initializer);

bool SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
                         ArrayRef<CXXCtorInitializer *> Initializers = None);

void SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation);


/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
/// mark all the non-trivial destructors of its members and bases as
/// referenced.
void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
                                            CXXRecordDecl *Record);

/// Mark destructors of virtual bases of this class referenced. In the Itanium
/// C++ ABI, this is done when emitting a destructor for any non-abstract
/// class. In the Microsoft C++ ABI, this is done any time a class's
/// destructor is referenced.
void MarkVirtualBaseDestructorsReferenced(
    SourceLocation Location, CXXRecordDecl *ClassDecl,
    llvm::SmallPtrSetImpl<const RecordType *> *DirectVirtualBases = nullptr);

/// Do semantic checks to allow the complete destructor variant to be emitted
/// when the destructor is defined in another translation unit. In the Itanium
/// C++ ABI, destructor variants are emitted together. In the MS C++ ABI, they
/// can be emitted in separate TUs. To emit the complete variant, run a subset
/// of the checks performed when emitting a regular destructor.
void CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
                                    CXXDestructorDecl *Dtor);

/// The list of classes whose vtables have been used within
/// this translation unit, and the source locations at which the
/// first use occurred.
typedef std::pair<CXXRecordDecl*, SourceLocation> VTableUse;

/// The list of vtables that are required but have not yet been
/// materialized.
SmallVector<VTableUse, 16> VTableUses;

/// The set of classes whose vtables have been used within
/// this translation unit, and a bit that will be true if the vtable is
/// required to be emitted (otherwise, it should be emitted only if needed
/// by code generation).
llvm::DenseMap<CXXRecordDecl *, bool> VTablesUsed;

/// Load any externally-stored vtable uses.
void LoadExternalVTableUses();

/// Note that the vtable for the given class was used at the
/// given location.
void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
                    bool DefinitionRequired = false);

/// Mark the exception specifications of all virtual member functions
/// in the given class as needed.
void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
                                           const CXXRecordDecl *RD);

/// MarkVirtualMembersReferenced - Will mark all members of the given
/// CXXRecordDecl referenced.
void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
                                  bool ConstexprOnly = false);

/// Define all of the vtables that have been used in this
/// translation unit and reference any virtual members used by those
/// vtables.
///
/// \returns true if any work was done, false otherwise.
bool DefineUsedVTables();

void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);

void ActOnMemInitializers(Decl *ConstructorDecl,
                          SourceLocation ColonLoc,
                          ArrayRef<CXXCtorInitializer*> MemInits,
                          bool AnyErrors);

/// Check class-level dllimport/dllexport attribute. The caller must
/// ensure that referenceDLLExportedClassMethods is called some point later
/// when all outer classes of Class are complete.
void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);

void referenceDLLExportedClassMethods();

void propagateDLLAttrToBaseClassTemplate(
    CXXRecordDecl *Class, Attr *ClassAttr,
    ClassTemplateSpecializationDecl *BaseTemplateSpec,
    SourceLocation BaseLoc);

/// Add gsl::Pointer attribute to std::container::iterator
/// \param ND The declaration that introduces the name
/// std::container::iterator. \param UnderlyingRecord The record named by ND.
void inferGslPointerAttribute(NamedDecl *ND, CXXRecordDecl *UnderlyingRecord);

/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);

/// Add [[gsl::Pointer]] attributes for std:: types.
void inferGslPointerAttribute(TypedefNameDecl *TD);

void CheckCompletedCXXClass(Scope *S, CXXRecordDecl *Record);

/// Check that the C++ class annoated with "trivial_abi" satisfies all the
/// conditions that are needed for the attribute to have an effect.
void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);

void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
                                       Decl *TagDecl, SourceLocation LBrac,
                                       SourceLocation RBrac,
                                       const ParsedAttributesView &AttrList);
void ActOnFinishCXXMemberDecls();
void ActOnFinishCXXNonNestedClass();

void ActOnReenterCXXMethodParameter(Scope *S, ParmVarDecl *Param);
unsigned ActOnReenterTemplateScope(Decl *Template,
                                   llvm::function_ref<Scope *()> EnterScope);
void ActOnStartDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnStartDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnDelayedCXXMethodParameter(Scope *S, Decl *Param);
void ActOnFinishDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnFinishDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnFinishDelayedMemberInitializers(Decl *Record);
void MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
                              CachedTokens &Toks);
void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
bool IsInsideALocalClassWithinATemplateFunction();

Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   Expr *AssertMessageExpr,
                                   SourceLocation RParenLoc);
Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   StringLiteral *AssertMessageExpr,
                                   SourceLocation RParenLoc,
                                   bool Failed);

FriendDecl *CheckFriendTypeDecl(SourceLocation LocStart,
                                SourceLocation FriendLoc,
                                TypeSourceInfo *TSInfo);
Decl *ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
                          MultiTemplateParamsArg TemplateParams);
NamedDecl *ActOnFriendFunctionDecl(Scope *S, Declarator &D,
                                   MultiTemplateParamsArg TemplateParams);

QualType CheckConstructorDeclarator(Declarator &D, QualType R,
                                    StorageClass& SC);
void CheckConstructor(CXXConstructorDecl *Constructor);
QualType CheckDestructorDeclarator(Declarator &D, QualType R,
                                   StorageClass& SC);
bool CheckDestructor(CXXDestructorDecl *Destructor);
void CheckConversionDeclarator(Declarator &D, QualType &R,
                               StorageClass& SC);
Decl *ActOnConversionDeclarator(CXXConversionDecl *Conversion);
void CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
                                   StorageClass &SC);
void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);

void CheckExplicitlyDefaultedFunction(Scope *S, FunctionDecl *MD);

bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
                                           CXXSpecialMember CSM);
void CheckDelayedMemberExceptionSpecs();

bool CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *MD,
                                        DefaultedComparisonKind DCK);
void DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
                                       FunctionDecl *Spaceship);
void DefineDefaultedComparison(SourceLocation Loc, FunctionDecl *FD,
                               DefaultedComparisonKind DCK);

//===--------------------------------------------------------------------===//
// C++ Derived Classes
//

/// ActOnBaseSpecifier - Parsed a base specifier
CXXBaseSpecifier *CheckBaseSpecifier(CXXRecordDecl *Class,
                                     SourceRange SpecifierRange,
                                     bool Virtual, AccessSpecifier Access,
                                     TypeSourceInfo *TInfo,
                                     SourceLocation EllipsisLoc);

BaseResult ActOnBaseSpecifier(Decl *classdecl,
                              SourceRange SpecifierRange,
                              ParsedAttributes &Attrs,
                              bool Virtual, AccessSpecifier Access,
                              ParsedType basetype,
                              SourceLocation BaseLoc,
                              SourceLocation EllipsisLoc);

bool AttachBaseSpecifiers(CXXRecordDecl *Class,
                          MutableArrayRef<CXXBaseSpecifier *> Bases);
void ActOnBaseSpecifiers(Decl *ClassDecl,
                         MutableArrayRef<CXXBaseSpecifier *> Bases);

bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
                   CXXBasePaths &Paths);

// FIXME: I don't like this name.
void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);

bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  SourceLocation Loc, SourceRange Range,
                                  CXXCastPath *BasePath = nullptr,
                                  bool IgnoreAccess = false);
bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  unsigned InaccessibleBaseID,
                                  unsigned AmbiguousBaseConvID,
                                  SourceLocation Loc, SourceRange Range,
                                  DeclarationName Name,
                                  CXXCastPath *BasePath,
                                  bool IgnoreAccess = false);

std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);

bool CheckOverridingFunctionAttributes(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionReturnType - Checks whether the return types are
/// covariant, according to C++ [class.virtual]p5.
bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
/// spec is a subset of base spec.
bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
                                          const CXXMethodDecl *Old);

bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);

/// CheckOverrideControl - Check C++11 override control semantics.
void CheckOverrideControl(NamedDecl *D);

/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
/// not used in the declaration of an overriding method.
void DiagnoseAbsenceOfOverrideControl(NamedDecl *D, bool Inconsistent);

/// CheckForFunctionMarkedFinal - Checks whether a virtual member function
/// overrides a virtual member function marked 'final', according to
/// C++11 [class.virtual]p4.
bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
                                            const CXXMethodDecl *Old);


//===--------------------------------------------------------------------===//
// C++ Access Control
//

enum AccessResult {
  AR_accessible,
  AR_inaccessible,
  AR_dependent,
  AR_delayed
};

bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
                              NamedDecl *PrevMemberDecl,
                              AccessSpecifier LexicalAS);

AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
                                   SourceRange PlacementRange,
                                   CXXRecordDecl *NamingClass,
                                   DeclAccessPair FoundDecl,
                                   bool Diagnose = true);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    bool IsCopyBindingRefToTemp = false);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    const PartialDiagnostic &PDiag);
AccessResult CheckDestructorAccess(SourceLocation Loc,
                                   CXXDestructorDecl *Dtor,
                                   const PartialDiagnostic &PDiag,
                                   QualType objectType = QualType());
AccessResult CheckFriendAccess(NamedDecl *D);
AccessResult CheckMemberAccess(SourceLocation UseLoc,
                               CXXRecordDecl *NamingClass,
                               DeclAccessPair Found);
AccessResult
CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
                                   CXXRecordDecl *DecomposedClass,
                                   DeclAccessPair Field);
AccessResult CheckMemberOperatorAccess(SourceLocation Loc,
                                       Expr *ObjectExpr,
                                       Expr *ArgExpr,
                                       DeclAccessPair FoundDecl);
AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
                                        DeclAccessPair FoundDecl);
AccessResult CheckBaseClassAccess(SourceLocation AccessLoc,
                                  QualType Base, QualType Derived,
                                  const CXXBasePath &Path,
                                  unsigned DiagID,
                                  bool ForceCheck = false,
                                  bool ForceUnprivileged = false);
void CheckLookupAccess(const LookupResult &R);
bool IsSimplyAccessible(NamedDecl *Decl, CXXRecordDecl *NamingClass,
                        QualType BaseType);
bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
                                   DeclAccessPair Found, QualType ObjectType,
                                   SourceLocation Loc,
                                   const PartialDiagnostic &Diag);
bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
                                   DeclAccessPair Found,
                                   QualType ObjectType) {
  return isMemberAccessibleForDeletion(NamingClass, Found, ObjectType,
                                       SourceLocation(), PDiag());
}

void HandleDependentAccessCheck(const DependentDiagnostic &DD,
                       const MultiLevelTemplateArgumentList &TemplateArgs);
void PerformDependentDiagnostics(const DeclContext *Pattern,
                      const MultiLevelTemplateArgumentList &TemplateArgs);

void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

/// When true, access checking violations are treated as SFINAE
/// failures rather than hard errors.
bool AccessCheckingSFINAE;

enum AbstractDiagSelID {
  AbstractNone = -1,
  AbstractReturnType,
  AbstractParamType,
  AbstractVariableType,
  AbstractFieldType,
  AbstractIvarType,
  AbstractSynthesizedIvarType,
  AbstractArrayType
};

bool isAbstractType(SourceLocation Loc, QualType T);
bool RequireNonAbstractType(SourceLocation Loc, QualType T,
                            TypeDiagnoser &Diagnoser);
template <typename... Ts>
bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
                            const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireNonAbstractType(Loc, T, Diagnoser);
}

void DiagnoseAbstractType(const CXXRecordDecl *RD);

//===--------------------------------------------------------------------===//
// C++ Overloaded Operators [C++ 13.5]
//

bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);

bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);

//===--------------------------------------------------------------------===//
// C++ Templates [C++ 14]
//
void FilterAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true);
bool hasAnyAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true,
                                   bool AllowNonTemplateFunctions = false);
/// Try to interpret the lookup result D as a template-name.
///
/// \param D A declaration found by name lookup.
/// \param AllowFunctionTemplates Whether function templates should be
///        considered valid results.
/// \param AllowDependent Whether unresolved using declarations (that might
///        name templates) should be considered valid results.
static NamedDecl *getAsTemplateNameDecl(NamedDecl *D,
                                        bool AllowFunctionTemplates = true,
                                        bool AllowDependent = true);

enum TemplateNameIsRequiredTag { TemplateNameIsRequired };
/// Whether and why a template name is required in this lookup.
class RequiredTemplateKind {
public:
  /// Template name is required if TemplateKWLoc is valid.
  RequiredTemplateKind(SourceLocation TemplateKWLoc = SourceLocation())
      : TemplateKW(TemplateKWLoc) {}
  /// Template name is unconditionally required.
  RequiredTemplateKind(TemplateNameIsRequiredTag) : TemplateKW() {}

  SourceLocation getTemplateKeywordLoc() const {
    return TemplateKW.getValueOr(SourceLocation());
  }
  bool hasTemplateKeyword() const { return getTemplateKeywordLoc().isValid(); }
  bool isRequired() const { return TemplateKW != SourceLocation(); }
  explicit operator bool() const { return isRequired(); }

private:
  llvm::Optional<SourceLocation> TemplateKW;
};

enum class AssumedTemplateKind {
  /// This is not assumed to be a template name.
  None,
  /// This is assumed to be a template name because lookup found nothing.
  FoundNothing,
  /// This is assumed to be a template name because lookup found one or more
  /// functions (but no function templates).
  FoundFunctions,
};
bool LookupTemplateName(
    LookupResult &R, Scope *S, CXXScopeSpec &SS, QualType ObjectType,
    bool EnteringContext, bool &MemberOfUnknownSpecialization,
    RequiredTemplateKind RequiredTemplate = SourceLocation(),
    AssumedTemplateKind *ATK = nullptr, bool AllowTypoCorrection = true);

TemplateNameKind isTemplateName(Scope *S,
                                CXXScopeSpec &SS,
                                bool hasTemplateKeyword,
                                const UnqualifiedId &Name,
                                ParsedType ObjectType,
                                bool EnteringContext,
                                TemplateTy &Template,
                                bool &MemberOfUnknownSpecialization,
                                bool Disambiguation = false);

/// Try to resolve an undeclared template name as a type template.
///
/// Sets II to the identifier corresponding to the template name, and updates
/// Name to a corresponding (typo-corrected) type template name and TNK to
/// the corresponding kind, if possible.
void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
                                     TemplateNameKind &TNK,
                                     SourceLocation NameLoc,
                                     IdentifierInfo *&II);

bool resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
                                      SourceLocation NameLoc,
                                      bool Diagnose = true);

/// Determine whether a particular identifier might be the name in a C++1z
/// deduction-guide declaration.
bool isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
                          SourceLocation NameLoc,
                          ParsedTemplateTy *Template = nullptr);

bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
                                 SourceLocation IILoc,
                                 Scope *S,
                                 const CXXScopeSpec *SS,
                                 TemplateTy &SuggestedTemplate,
                                 TemplateNameKind &SuggestedKind);

bool DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
                                    NamedDecl *Instantiation,
                                    bool InstantiatedFromMember,
                                    const NamedDecl *Pattern,
                                    const NamedDecl *PatternDef,
                                    TemplateSpecializationKind TSK,
                                    bool Complain = true);

void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl);
TemplateDecl *AdjustDeclIfTemplate(Decl *&Decl);

NamedDecl *ActOnTypeParameter(Scope *S, bool Typename,
                              SourceLocation EllipsisLoc,
                              SourceLocation KeyLoc,
                              IdentifierInfo *ParamName,
                              SourceLocation ParamNameLoc,
                              unsigned Depth, unsigned Position,
                              SourceLocation EqualLoc,
                              ParsedType DefaultArg, bool HasTypeConstraint);

bool ActOnTypeConstraint(const CXXScopeSpec &SS,
                         TemplateIdAnnotation *TypeConstraint,
                         TemplateTypeParmDecl *ConstrainedParameter,
                         SourceLocation EllipsisLoc);
bool BuildTypeConstraint(const CXXScopeSpec &SS,
                         TemplateIdAnnotation *TypeConstraint,
                         TemplateTypeParmDecl *ConstrainedParameter,
                         SourceLocation EllipsisLoc,
                         bool AllowUnexpandedPack);

bool AttachTypeConstraint(NestedNameSpecifierLoc NS,
                          DeclarationNameInfo NameInfo,
                          ConceptDecl *NamedConcept,
                          const TemplateArgumentListInfo *TemplateArgs,
                          TemplateTypeParmDecl *ConstrainedParameter,
                          SourceLocation EllipsisLoc);

bool AttachTypeConstraint(AutoTypeLoc TL,
                          NonTypeTemplateParmDecl *ConstrainedParameter,
                          SourceLocation EllipsisLoc);

bool RequireStructuralType(QualType T, SourceLocation Loc);

QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
                                           SourceLocation Loc);
QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);

NamedDecl *ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
                                    unsigned Depth,
                                    unsigned Position,
                                    SourceLocation EqualLoc,
                                    Expr *DefaultArg);
NamedDecl *ActOnTemplateTemplateParameter(Scope *S,
                                     SourceLocation TmpLoc,
                                     TemplateParameterList *Params,
                                     SourceLocation EllipsisLoc,
                                     IdentifierInfo *ParamName,
                                     SourceLocation ParamNameLoc,
                                     unsigned Depth,
                                     unsigned Position,
                                     SourceLocation EqualLoc,
                                     ParsedTemplateArgument DefaultArg);

TemplateParameterList *
ActOnTemplateParameterList(unsigned Depth,
                           SourceLocation ExportLoc,
                           SourceLocation TemplateLoc,
                           SourceLocation LAngleLoc,
                           ArrayRef<NamedDecl *> Params,
                           SourceLocation RAngleLoc,
                           Expr *RequiresClause);

/// The context in which we are checking a template parameter list.
enum TemplateParamListContext {
  TPC_ClassTemplate,
  TPC_VarTemplate,
  TPC_FunctionTemplate,
  TPC_ClassTemplateMember,
  TPC_FriendClassTemplate,
  TPC_FriendFunctionTemplate,
  TPC_FriendFunctionTemplateDefinition,
  TPC_TypeAliasTemplate
};

bool CheckTemplateParameterList(TemplateParameterList *NewParams,
                                TemplateParameterList *OldParams,
                                TemplateParamListContext TPC,
                                SkipBodyInfo *SkipBody = nullptr);
TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
    SourceLocation DeclStartLoc, SourceLocation DeclLoc,
    const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
    ArrayRef<TemplateParameterList *> ParamLists,
    bool IsFriend, bool &IsMemberSpecialization, bool &Invalid,
    bool SuppressDiagnostic = false);

DeclResult CheckClassTemplate(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
    const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
    AccessSpecifier AS, SourceLocation ModulePrivateLoc,
    SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
    TemplateParameterList **OuterTemplateParamLists,
    SkipBodyInfo *SkipBody = nullptr);

TemplateArgumentLoc getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
                                                  QualType NTTPType,
                                                  SourceLocation Loc);

/// Get a template argument mapping the given template parameter to itself,
/// e.g. for X in \c template<int X>, this would return an expression template
/// argument referencing X.
TemplateArgumentLoc getIdentityTemplateArgumentLoc(NamedDecl *Param,
                                                   SourceLocation Location);

void translateTemplateArguments(const ASTTemplateArgsPtr &In,
                                TemplateArgumentListInfo &Out);

ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);

void NoteAllFoundTemplates(TemplateName Name);

QualType CheckTemplateIdType(TemplateName Template,
                             SourceLocation TemplateLoc,
                            TemplateArgumentListInfo &TemplateArgs);

TypeResult
ActOnTemplateIdType(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
                    TemplateTy Template, IdentifierInfo *TemplateII,
                    SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                    ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
                    bool IsCtorOrDtorName = false, bool IsClassName = false);

/// Parsed an elaborated-type-specifier that refers to a template-id,
/// such as \c class T::template apply<U>.
TypeResult ActOnTagTemplateIdType(TagUseKind TUK,
                                  TypeSpecifierType TagSpec,
                                  SourceLocation TagLoc,
                                  CXXScopeSpec &SS,
                                  SourceLocation TemplateKWLoc,
                                  TemplateTy TemplateD,
                                  SourceLocation TemplateLoc,
                                  SourceLocation LAngleLoc,
                                  ASTTemplateArgsPtr TemplateArgsIn,
                                  SourceLocation RAngleLoc);

DeclResult ActOnVarTemplateSpecialization(
    Scope *S, Declarator &D, TypeSourceInfo *DI,
    SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
    StorageClass SC, bool IsPartialSpecialization);

/// Get the specialization of the given variable template corresponding to
/// the specified argument list, or a null-but-valid result if the arguments
/// are dependent.
DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              SourceLocation TemplateNameLoc,
                              const TemplateArgumentListInfo &TemplateArgs);

/// Form a reference to the specialization of the given variable template
/// corresponding to the specified argument list, or a null-but-valid result
/// if the arguments are dependent.
ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
                              const DeclarationNameInfo &NameInfo,
                              VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult
CheckConceptTemplateId(const CXXScopeSpec &SS,
                       SourceLocation TemplateKWLoc,
                       const DeclarationNameInfo &ConceptNameInfo,
                       NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
                       const TemplateArgumentListInfo *TemplateArgs);

void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);

ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
                               SourceLocation TemplateKWLoc,
                               LookupResult &R,
                               bool RequiresADL,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
                                        SourceLocation TemplateKWLoc,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

TemplateNameKind ActOnTemplateName(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    const UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext,
    TemplateTy &Template, bool AllowInjectedClassName = false);

DeclResult ActOnClassTemplateSpecialization(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
    TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
    MultiTemplateParamsArg TemplateParameterLists,
    SkipBodyInfo *SkipBody = nullptr);

bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
                                            TemplateDecl *PrimaryTemplate,
                                            unsigned NumExplicitArgs,
                                            ArrayRef<TemplateArgument> Args);
void CheckTemplatePartialSpecialization(
    ClassTemplatePartialSpecializationDecl *Partial);
void CheckTemplatePartialSpecialization(
    VarTemplatePartialSpecializationDecl *Partial);

Decl *ActOnTemplateDeclarator(Scope *S,
                              MultiTemplateParamsArg TemplateParameterLists,
                              Declarator &D);

bool
CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
                                       TemplateSpecializationKind NewTSK,
                                       NamedDecl *PrevDecl,
                                       TemplateSpecializationKind PrevTSK,
                                       SourceLocation PrevPtOfInstantiation,
                                       bool &SuppressNew);

bool CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
                  const TemplateArgumentListInfo &ExplicitTemplateArgs,
                                                  LookupResult &Previous);

bool CheckFunctionTemplateSpecialization(
    FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
    LookupResult &Previous, bool QualifiedFriend = false);
bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);

DeclResult ActOnExplicitInstantiation(
    Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
    unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
    TemplateTy Template, SourceLocation TemplateNameLoc,
    SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
    SourceLocation RAngleLoc, const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      unsigned TagSpec, SourceLocation KWLoc,
                                      CXXScopeSpec &SS, IdentifierInfo *Name,
                                      SourceLocation NameLoc,
                                      const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S,
                                      SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      Declarator &D);

TemplateArgumentLoc
SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
                                        SourceLocation TemplateLoc,
                                        SourceLocation RAngleLoc,
                                        Decl *Param,
                                        SmallVectorImpl<TemplateArgument>
                                          &Converted,
                                        bool &HasDefaultArg);

/// Specifies the context in which a particular template
/// argument is being checked.
enum CheckTemplateArgumentKind {
  /// The template argument was specified in the code or was
  /// instantiated with some deduced template arguments.
  CTAK_Specified,

  /// The template argument was deduced via template argument
  /// deduction.
  CTAK_Deduced,

  /// The template argument was deduced from an array bound
  /// via template argument deduction.
  CTAK_DeducedFromArrayBound
};

bool CheckTemplateArgument(NamedDecl *Param,
                           TemplateArgumentLoc &Arg,
                           NamedDecl *Template,
                           SourceLocation TemplateLoc,
                           SourceLocation RAngleLoc,
                           unsigned ArgumentPackIndex,
                         SmallVectorImpl<TemplateArgument> &Converted,
                           CheckTemplateArgumentKind CTAK = CTAK_Specified);

/// Check that the given template arguments can be be provided to
/// the given template, converting the arguments along the way.
///
/// \param Template The template to which the template arguments are being
/// provided.
///
/// \param TemplateLoc The location of the template name in the source.
///
/// \param TemplateArgs The list of template arguments. If the template is
/// a template template parameter, this function may extend the set of
/// template arguments to also include substituted, defaulted template
/// arguments.
///
/// \param PartialTemplateArgs True if the list of template arguments is
/// intentionally partial, e.g., because we're checking just the initial
/// set of template arguments.
///
/// \param Converted Will receive the converted, canonicalized template
/// arguments.
///
/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
/// contain the converted forms of the template arguments as written.
/// Otherwise, \p TemplateArgs will not be modified.
///
/// \param ConstraintsNotSatisfied If provided, and an error occured, will
/// receive true if the cause for the error is the associated constraints of
/// the template not being satisfied by the template arguments.
///
/// \returns true if an error occurred, false otherwise.
bool CheckTemplateArgumentList(TemplateDecl *Template,
                               SourceLocation TemplateLoc,
                               TemplateArgumentListInfo &TemplateArgs,
                               bool PartialTemplateArgs,
                               SmallVectorImpl<TemplateArgument> &Converted,
                               bool UpdateArgsWithConversions = true,
                               bool *ConstraintsNotSatisfied = nullptr);

bool CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
                               TemplateArgumentLoc &Arg,
                         SmallVectorImpl<TemplateArgument> &Converted);

bool CheckTemplateArgument(TypeSourceInfo *Arg);
ExprResult CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
                                 QualType InstantiatedParamType, Expr *Arg,
                                 TemplateArgument &Converted,
                             CheckTemplateArgumentKind CTAK = CTAK_Specified);
bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
                                   TemplateParameterList *Params,
                                   TemplateArgumentLoc &Arg);

ExprResult
BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
                                        QualType ParamType,
                                        SourceLocation Loc);
ExprResult
BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
                                            SourceLocation Loc);

/// Enumeration describing how template parameter lists are compared
/// for equality.
enum TemplateParameterListEqualKind {
  /// We are matching the template parameter lists of two templates
  /// that might be redeclarations.
  ///
  /// \code
  /// template<typename T> struct X;
  /// template<typename T> struct X;
  /// \endcode
  TPL_TemplateMatch,

  /// We are matching the template parameter lists of two template
  /// template parameters as part of matching the template parameter lists
  /// of two templates that might be redeclarations.
  ///
  /// \code
  /// template<template<int I> class TT> struct X;
  /// template<template<int Value> class Other> struct X;
  /// \endcode
  TPL_TemplateTemplateParmMatch,

  /// We are matching the template parameter lists of a template
  /// template argument against the template parameter lists of a template
  /// template parameter.
  ///
  /// \code
  /// template<template<int Value> class Metafun> struct X;
  /// template<int Value> struct integer_c;
  /// X<integer_c> xic;
  /// \endcode
  TPL_TemplateTemplateArgumentMatch
};

bool TemplateParameterListsAreEqual(TemplateParameterList *New,
                                    TemplateParameterList *Old,
                                    bool Complain,
                                    TemplateParameterListEqualKind Kind,
                                    SourceLocation TemplateArgLoc
                                      = SourceLocation());

bool CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams);

/// Called when the parser has parsed a C++ typename
/// specifier, e.g., "typename T::type".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param II the identifier we're retrieving (e.g., 'type' in the example).
/// \param IdLoc the location of the identifier.
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS, const IdentifierInfo &II,
                  SourceLocation IdLoc);

/// Called when the parser has parsed a C++ typename
/// specifier that ends in a template-id, e.g.,
/// "typename MetaFun::template apply<T1, T2>".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param TemplateLoc the location of the 'template' keyword, if any.
/// \param TemplateName The template name.
/// \param TemplateII The identifier used to name the template.
/// \param TemplateIILoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS,
                  SourceLocation TemplateLoc,
                  TemplateTy TemplateName,
                  IdentifierInfo *TemplateII,
                  SourceLocation TemplateIILoc,
                  SourceLocation LAngleLoc,
                  ASTTemplateArgsPtr TemplateArgs,
                  SourceLocation RAngleLoc);

QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
                           SourceLocation KeywordLoc,
                           NestedNameSpecifierLoc QualifierLoc,
                           const IdentifierInfo &II,
                           SourceLocation IILoc,
                           TypeSourceInfo **TSI,
                           bool DeducedTSTContext);

QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
                           SourceLocation KeywordLoc,
                           NestedNameSpecifierLoc QualifierLoc,
                           const IdentifierInfo &II,
                           SourceLocation IILoc,
                           bool DeducedTSTContext = true);


TypeSourceInfo *RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
                                                  SourceLocation Loc,
                                                  DeclarationName Name);
bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);

ExprResult RebuildExprInCurrentInstantiation(Expr *E);
bool RebuildTemplateParamsInCurrentInstantiation(
                                              TemplateParameterList *Params);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgumentList &Args);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgument *Args,
                                unsigned NumArgs);

//===--------------------------------------------------------------------===//
// C++ Concepts
//===--------------------------------------------------------------------===//
Decl *ActOnConceptDefinition(
    Scope *S, MultiTemplateParamsArg TemplateParameterLists,
    IdentifierInfo *Name, SourceLocation NameLoc, Expr *ConstraintExpr);

RequiresExprBodyDecl *
ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
                       ArrayRef<ParmVarDecl *> LocalParameters,
                       Scope *BodyScope);
void ActOnFinishRequiresExpr();
concepts::Requirement *ActOnSimpleRequirement(Expr *E);
concepts::Requirement *ActOnTypeRequirement(
    SourceLocation TypenameKWLoc, CXXScopeSpec &SS, SourceLocation NameLoc,
    IdentifierInfo *TypeName, TemplateIdAnnotation *TemplateId);
concepts::Requirement *ActOnCompoundRequirement(Expr *E,
                                                SourceLocation NoexceptLoc);
concepts::Requirement *
ActOnCompoundRequirement(
    Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
    TemplateIdAnnotation *TypeConstraint, unsigned Depth);
concepts::Requirement *ActOnNestedRequirement(Expr *Constraint);
concepts::ExprRequirement *
BuildExprRequirement(
    Expr *E, bool IsSatisfied, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
concepts::ExprRequirement *
BuildExprRequirement(
    concepts::Requirement::SubstitutionDiagnostic *ExprSubstDiag,
    bool IsSatisfied, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
concepts::TypeRequirement *BuildTypeRequirement(TypeSourceInfo *Type);
concepts::TypeRequirement *
BuildTypeRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
concepts::NestedRequirement *BuildNestedRequirement(Expr *E);
concepts::NestedRequirement *
BuildNestedRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
                             RequiresExprBodyDecl *Body,
                             ArrayRef<ParmVarDecl *> LocalParameters,
                             ArrayRef<concepts::Requirement *> Requirements,
                             SourceLocation ClosingBraceLoc);

//===--------------------------------------------------------------------===//
// C++ Variadic Templates (C++0x [temp.variadic])
//===--------------------------------------------------------------------===//

/// Determine whether an unexpanded parameter pack might be permitted in this
/// location. Useful for error recovery.
bool isUnexpandedParameterPackPermitted();

/// The context in which an unexpanded parameter pack is
/// being diagnosed.
///
/// Note that the values of this enumeration line up with the first
/// argument to the \c err_unexpanded_parameter_pack diagnostic.
enum UnexpandedParameterPackContext {
  /// An arbitrary expression.
  UPPC_Expression = 0,

  /// The base type of a class type.
  UPPC_BaseType,

  /// The type of an arbitrary declaration.
  UPPC_DeclarationType,

  /// The type of a data member.
  UPPC_DataMemberType,

  /// The size of a bit-field.
  UPPC_BitFieldWidth,

  /// The expression in a static assertion.
  UPPC_StaticAssertExpression,

  /// The fixed underlying type of an enumeration.
  UPPC_FixedUnderlyingType,

  /// The enumerator value.
  UPPC_EnumeratorValue,

  /// A using declaration.
  UPPC_UsingDeclaration,

  /// A friend declaration.
  UPPC_FriendDeclaration,

  /// A declaration qualifier.
  UPPC_DeclarationQualifier,

  /// An initializer.
  UPPC_Initializer,

  /// A default argument.
  UPPC_DefaultArgument,

  /// The type of a non-type template parameter.
  UPPC_NonTypeTemplateParameterType,

  /// The type of an exception.
  UPPC_ExceptionType,

  /// Partial specialization.
  UPPC_PartialSpecialization,

  /// Microsoft __if_exists.
  UPPC_IfExists,

  /// Microsoft __if_not_exists.
  UPPC_IfNotExists,

  /// Lambda expression.
  UPPC_Lambda,

  /// Block expression.
  UPPC_Block,

  /// A type constraint.
  UPPC_TypeConstraint,

  // A requirement in a requires-expression.
  UPPC_Requirement,

  // A requires-clause.
  UPPC_RequiresClause,
};

/// Diagnose unexpanded parameter packs.
///
/// \param Loc The location at which we should emit the diagnostic.
///
/// \param UPPC The context in which we are diagnosing unexpanded
/// parameter packs.
///
/// \param Unexpanded the set of unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
                                      UnexpandedParameterPackContext UPPC,
                                ArrayRef<UnexpandedParameterPack> Unexpanded);

/// If the given type contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The source location where a diagnostc should be emitted.
///
/// \param T The type that is being checked for unexpanded parameter
/// packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
                                     UnexpandedParameterPackContext UPPC);

/// If the given expression contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param E The expression that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(Expr *E,
                     UnexpandedParameterPackContext UPPC = UPPC_Expression);

/// If the given requirees-expression contains an unexpanded reference to one
/// of its own parameter packs, diagnose the error.
///
/// \param RE The requiress-expression that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPackInRequiresExpr(RequiresExpr *RE);

/// If the given nested-name-specifier contains an unexpanded
/// parameter pack, diagnose the error.
///
/// \param SS The nested-name-specifier that is being checked for
/// unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
                                     UnexpandedParameterPackContext UPPC);

/// If the given name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param NameInfo The name (with source location information) that
/// is being checked for unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The location of the template name.
///
/// \param Template The template name that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
                                     TemplateName Template,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template argument contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param Arg The template argument that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
                                     UnexpandedParameterPackContext UPPC);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgument Arg,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgumentLoc Arg,
                  SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param T The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(QualType T,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param TL The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TypeLoc TL,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// nested-name-specifier.
///
/// \param NNS The nested-name-specifier that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(NestedNameSpecifierLoc NNS,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// name.
///
/// \param NameInfo The name that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(const DeclarationNameInfo &NameInfo,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Invoked when parsing a template argument followed by an
/// ellipsis, which creates a pack expansion.
///
/// \param Arg The template argument preceding the ellipsis, which
/// may already be invalid.
///
/// \param EllipsisLoc The location of the ellipsis.
ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
                                          SourceLocation EllipsisLoc);

/// Invoked when parsing a type followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Type The type preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
TypeSourceInfo *CheckPackExpansion(TypeSourceInfo *Pattern,
                                   SourceLocation EllipsisLoc,
                                   Optional<unsigned> NumExpansions);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
QualType CheckPackExpansion(QualType Pattern,
                            SourceRange PatternRange,
                            SourceLocation EllipsisLoc,
                            Optional<unsigned> NumExpansions);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
                              Optional<unsigned> NumExpansions);

/// Determine whether we could expand a pack expansion with the
/// given set of parameter packs into separate arguments by repeatedly
/// transforming the pattern.
///
/// \param EllipsisLoc The location of the ellipsis that identifies the
/// pack expansion.
///
/// \param PatternRange The source range that covers the entire pattern of
/// the pack expansion.
///
/// \param Unexpanded The set of unexpanded parameter packs within the
/// pattern.
///
/// \param ShouldExpand Will be set to \c true if the transformer should
/// expand the corresponding pack expansions into separate arguments. When
/// set, \c NumExpansions must also be set.
///
/// \param RetainExpansion Whether the caller should add an unexpanded
/// pack expansion after all of the expanded arguments. This is used
/// when extending explicitly-specified template argument packs per
/// C++0x [temp.arg.explicit]p9.
///
/// \param NumExpansions The number of separate arguments that will be in
/// the expanded form of the corresponding pack expansion. This is both an
/// input and an output parameter, which can be set by the caller if the
/// number of expansions is known a priori (e.g., due to a prior substitution)
/// and will be set by the callee when the number of expansions is known.
/// The callee must set this value when \c ShouldExpand is \c true; it may
/// set this value in other cases.
///
/// \returns true if an error occurred (e.g., because the parameter packs
/// are to be instantiated with arguments of different lengths), false
/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
/// must be set.
bool CheckParameterPacksForExpansion(SourceLocation EllipsisLoc,
                                     SourceRange PatternRange,
                           ArrayRef<UnexpandedParameterPack> Unexpanded,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                                     bool &ShouldExpand,
                                     bool &RetainExpansion,
                                     Optional<unsigned> &NumExpansions);

/// Determine the number of arguments in the given pack expansion
/// type.
///
/// This routine assumes that the number of arguments in the expansion is
/// consistent across all of the unexpanded parameter packs in its pattern.
///
/// Returns an empty Optional if the type can't be expanded.
Optional<unsigned> getNumArgumentsInExpansion(QualType T,
    const MultiLevelTemplateArgumentList &TemplateArgs);

/// Determine whether the given declarator contains any unexpanded
/// parameter packs.
///
/// This routine is used by the parser to disambiguate function declarators
/// with an ellipsis prior to the ')', e.g.,
///
/// \code
///   void f(T...);
/// \endcode
///
/// To determine whether we have an (unnamed) function parameter pack or
/// a variadic function.
///
/// \returns true if the declarator contains any unexpanded parameter packs,
/// false otherwise.
bool containsUnexpandedParameterPacks(Declarator &D);

/// Returns the pattern of the pack expansion for a template argument.
///
/// \param OrigLoc The template argument to expand.
///
/// \param Ellipsis Will be set to the location of the ellipsis.
///
/// \param NumExpansions Will be set to the number of expansions that will
/// be generated from this pack expansion, if known a priori.
TemplateArgumentLoc getTemplateArgumentPackExpansionPattern(
    TemplateArgumentLoc OrigLoc,
    SourceLocation &Ellipsis,
    Optional<unsigned> &NumExpansions) const;

/// Given a template argument that contains an unexpanded parameter pack, but
/// which has already been substituted, attempt to determine the number of
/// elements that will be produced once this argument is fully-expanded.
///
/// This is intended for use when transforming 'sizeof...(Arg)' in order to
/// avoid actually expanding the pack where possible.
Optional<unsigned> getFullyPackExpandedSize(TemplateArgument Arg);

//===--------------------------------------------------------------------===//
// C++ Template Argument Deduction (C++ [temp.deduct])
//===--------------------------------------------------------------------===//

/// Adjust the type \p ArgFunctionType to match the calling convention,
/// noreturn, and optionally the exception specification of \p FunctionType.
/// Deduction often wants to ignore these properties when matching function
/// types.
QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
                             bool AdjustExceptionSpec = false);

/// Describes the result of template argument deduction.
///
/// The TemplateDeductionResult enumeration describes the result of
/// template argument deduction, as returned from
/// DeduceTemplateArguments(). The separate TemplateDeductionInfo
/// structure provides additional information about the results of
/// template argument deduction, e.g., the deduced template argument
/// list (if successful) or the specific template parameters or
/// deduced arguments that were involved in the failure.
enum TemplateDeductionResult {
  /// Template argument deduction was successful.
  TDK_Success = 0,
  /// The declaration was invalid; do nothing.
  TDK_Invalid,
  /// Template argument deduction exceeded the maximum template
  /// instantiation depth (which has already been diagnosed).
  TDK_InstantiationDepth,
  /// Template argument deduction did not deduce a value
  /// for every template parameter.
  TDK_Incomplete,
  /// Template argument deduction did not deduce a value for every
  /// expansion of an expanded template parameter pack.
  TDK_IncompletePack,
  /// Template argument deduction produced inconsistent
  /// deduced values for the given template parameter.
  TDK_Inconsistent,
  /// Template argument deduction failed due to inconsistent
  /// cv-qualifiers on a template parameter type that would
  /// otherwise be deduced, e.g., we tried to deduce T in "const T"
  /// but were given a non-const "X".
  TDK_Underqualified,
  /// Substitution of the deduced template argument values
  /// resulted in an error.
  TDK_SubstitutionFailure,
  /// After substituting deduced template arguments, a dependent
  /// parameter type did not match the corresponding argument.
  TDK_DeducedMismatch,
  /// After substituting deduced template arguments, an element of
  /// a dependent parameter type did not match the corresponding element
  /// of the corresponding argument (when deducing from an initializer list).
  TDK_DeducedMismatchNested,
  /// A non-depnedent component of the parameter did not match the
  /// corresponding component of the argument.
  TDK_NonDeducedMismatch,
  /// When performing template argument deduction for a function
  /// template, there were too many call arguments.
  TDK_TooManyArguments,
  /// When performing template argument deduction for a function
  /// template, there were too few call arguments.
  TDK_TooFewArguments,
  /// The explicitly-specified template arguments were not valid
  /// template arguments for the given template.
  TDK_InvalidExplicitArguments,
  /// Checking non-dependent argument conversions failed.
  TDK_NonDependentConversionFailure,
  /// The deduced arguments did not satisfy the constraints associated
  /// with the template.
  TDK_ConstraintsNotSatisfied,
  /// Deduction failed; that's all we know.
  TDK_MiscellaneousDeductionFailure,
  /// CUDA Target attributes do not match.
  TDK_CUDATargetMismatch
};

TemplateDeductionResult
DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult SubstituteExplicitTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo &ExplicitTemplateArgs,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
    sema::TemplateDeductionInfo &Info);

/// brief A function argument from which we performed template argument
// deduction for a call.
struct OriginalCallArg {
  OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
                  unsigned ArgIdx, QualType OriginalArgType)
      : OriginalParamType(OriginalParamType),
        DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
        OriginalArgType(OriginalArgType) {}

  QualType OriginalParamType;
  bool DecomposedParam;
  unsigned ArgIdx;
  QualType OriginalArgType;
};

TemplateDeductionResult FinishTemplateArgumentDeduction(
    FunctionTemplateDecl *FunctionTemplate,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
    sema::TemplateDeductionInfo &Info,
    SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs = nullptr,
    bool PartialOverloading = false,
    llvm::function_ref<bool()> CheckNonDependent = []{ return false; });

TemplateDeductionResult DeduceTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
    bool PartialOverloading,
    llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        QualType ArgFunctionType,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        QualType ToType,
                        CXXConversionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

/// Substitute Replacement for \p auto in \p TypeWithAuto
QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
/// Substitute Replacement for auto in TypeWithAuto
TypeSourceInfo* SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                        QualType Replacement);
/// Completely replace the \c auto in \p TypeWithAuto by
/// \p Replacement. This does not retain any \c auto type sugar.
QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);
TypeSourceInfo *ReplaceAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                          QualType Replacement);

/// Result type of DeduceAutoType.
enum DeduceAutoResult {
  DAR_Succeeded,
  DAR_Failed,
  DAR_FailedAlreadyDiagnosed
};

DeduceAutoResult
DeduceAutoType(TypeSourceInfo *AutoType, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None,
               bool IgnoreConstraints = false);
DeduceAutoResult
DeduceAutoType(TypeLoc AutoTypeLoc, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None,
               bool IgnoreConstraints = false);
void DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init);
bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
                      bool Diagnose = true);

/// Declare implicit deduction guides for a class template if we've
/// not already done so.
void DeclareImplicitDeductionGuides(TemplateDecl *Template,
                                    SourceLocation Loc);

QualType DeduceTemplateSpecializationFromInitializer(
    TypeSourceInfo *TInfo, const InitializedEntity &Entity,
    const InitializationKind &Kind, MultiExprArg Init);

QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
                                      QualType Type, TypeSourceInfo *TSI,
                                      SourceRange Range, bool DirectInit,
                                      Expr *Init);

TypeLoc getReturnTypeLoc(FunctionDecl *FD) const;

bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
                                      SourceLocation ReturnLoc,
                                      Expr *&RetExpr, AutoType *AT);

FunctionTemplateDecl *getMoreSpecializedTemplate(
    FunctionTemplateDecl *FT1, FunctionTemplateDecl *FT2, SourceLocation Loc,
    TemplatePartialOrderingContext TPOC, unsigned NumCallArguments1,
    unsigned NumCallArguments2, bool Reversed = false);
UnresolvedSetIterator
getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
                   TemplateSpecCandidateSet &FailedCandidates,
                   SourceLocation Loc,
                   const PartialDiagnostic &NoneDiag,
                   const PartialDiagnostic &AmbigDiag,
                   const PartialDiagnostic &CandidateDiag,
                   bool Complain = true, QualType TargetType = QualType());

ClassTemplatePartialSpecializationDecl *
getMoreSpecializedPartialSpecialization(
                                ClassTemplatePartialSpecializationDecl *PS1,
                                ClassTemplatePartialSpecializationDecl *PS2,
                                SourceLocation Loc);

bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
    VarTemplatePartialSpecializationDecl *PS1,
    VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);

bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
    TemplateParameterList *PParam, TemplateDecl *AArg, SourceLocation Loc);

void MarkUsedTemplateParameters(const Expr *E, bool OnlyDeduced,
                                unsigned Depth, llvm::SmallBitVector &Used);

void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
                                bool OnlyDeduced,
                                unsigned Depth,
                                llvm::SmallBitVector &Used);
void MarkDeducedTemplateParameters(
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced) {
  return MarkDeducedTemplateParameters(Context, FunctionTemplate, Deduced);
}
static void MarkDeducedTemplateParameters(ASTContext &Ctx,
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced);

//===--------------------------------------------------------------------===//
// C++ Template Instantiation
//

MultiLevelTemplateArgumentList
getTemplateInstantiationArgs(NamedDecl *D,
                             const TemplateArgumentList *Innermost = nullptr,
                             bool RelativeToPrimary = false,
                             const FunctionDecl *Pattern = nullptr);

/// A context in which code is being synthesized (where a source location
/// alone is not sufficient to identify the context). This covers template
/// instantiation and various forms of implicitly-generated functions.
struct CodeSynthesisContext {
  /// The kind of template instantiation we are performing
  enum SynthesisKind {
    /// We are instantiating a template declaration. The entity is
    /// the declaration we're instantiating (e.g., a CXXRecordDecl).
    TemplateInstantiation,

    /// We are instantiating a default argument for a template
    /// parameter. The Entity is the template parameter whose argument is
    /// being instantiated, the Template is the template, and the
    /// TemplateArgs/NumTemplateArguments provide the template arguments as
    /// specified.
    DefaultTemplateArgumentInstantiation,

    /// We are instantiating a default argument for a function.
    /// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
    /// provides the template arguments as specified.
    DefaultFunctionArgumentInstantiation,

    /// We are substituting explicit template arguments provided for
    /// a function template. The entity is a FunctionTemplateDecl.
    ExplicitTemplateArgumentSubstitution,

    /// We are substituting template argument determined as part of
    /// template argument deduction for either a class template
    /// partial specialization or a function template. The
    /// Entity is either a {Class|Var}TemplatePartialSpecializationDecl or
    /// a TemplateDecl.
    DeducedTemplateArgumentSubstitution,

    /// We are substituting prior template arguments into a new
    /// template parameter. The template parameter itself is either a
    /// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
    PriorTemplateArgumentSubstitution,

    /// We are checking the validity of a default template argument that
    /// has been used when naming a template-id.
    DefaultTemplateArgumentChecking,

    /// We are computing the exception specification for a defaulted special
    /// member function.
    ExceptionSpecEvaluation,

    /// We are instantiating the exception specification for a function
    /// template which was deferred until it was needed.
    ExceptionSpecInstantiation,

    /// We are instantiating a requirement of a requires expression.
    RequirementInstantiation,

    /// We are checking the satisfaction of a nested requirement of a requires
    /// expression.
    NestedRequirementConstraintsCheck,

    /// We are declaring an implicit special member function.
    DeclaringSpecialMember,

    /// We are declaring an implicit 'operator==' for a defaulted
    /// 'operator<=>'.
    DeclaringImplicitEqualityComparison,

    /// We are defining a synthesized function (such as a defaulted special
    /// member).
    DefiningSynthesizedFunction,

    // We are checking the constraints associated with a constrained entity or
    // the constraint expression of a concept. This includes the checks that
    // atomic constraints have the type 'bool' and that they can be constant
    // evaluated.
    ConstraintsCheck,

    // We are substituting template arguments into a constraint expression.
    ConstraintSubstitution,

    // We are normalizing a constraint expression.
    ConstraintNormalization,

    // We are substituting into the parameter mapping of an atomic constraint
    // during normalization.
    ParameterMappingSubstitution,

    /// We are rewriting a comparison operator in terms of an operator<=>.
    RewritingOperatorAsSpaceship,

    /// We are initializing a structured binding.
    InitializingStructuredBinding,

    /// We are marking a class as __dllexport.
    MarkingClassDllexported,

    /// Added for Template instantiation observation.
    /// Memoization means we are _not_ instantiating a template because
    /// it is already instantiated (but we entered a context where we
    /// would have had to if it was not already instantiated).
    Memoization
  } Kind;

  /// Was the enclosing context a non-instantiation SFINAE context?
  bool SavedInNonInstantiationSFINAEContext;

  /// The point of instantiation or synthesis within the source code.
  SourceLocation PointOfInstantiation;

  /// The entity that is being synthesized.
  Decl *Entity;

  /// The template (or partial specialization) in which we are
  /// performing the instantiation, for substitutions of prior template
  /// arguments.
  NamedDecl *Template;

  /// The list of template arguments we are substituting, if they
  /// are not part of the entity.
  const TemplateArgument *TemplateArgs;

  // FIXME: Wrap this union around more members, or perhaps store the
  // kind-specific members in the RAII object owning the context.
  union {
    /// The number of template arguments in TemplateArgs.
    unsigned NumTemplateArgs;

    /// The special member being declared or defined.
    CXXSpecialMember SpecialMember;
  };

  ArrayRef<TemplateArgument> template_arguments() const {
    assert(Kind != DeclaringSpecialMember)((void)0);
    return {TemplateArgs, NumTemplateArgs};
  }

  /// The template deduction info object associated with the
  /// substitution or checking of explicit or deduced template arguments.
  sema::TemplateDeductionInfo *DeductionInfo;

  /// The source range that covers the construct that cause
  /// the instantiation, e.g., the template-id that causes a class
  /// template instantiation.
  SourceRange InstantiationRange;

  CodeSynthesisContext()
      : Kind(TemplateInstantiation),
        SavedInNonInstantiationSFINAEContext(false), Entity(nullptr),
        Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(0),
        DeductionInfo(nullptr) {}

  /// Determines whether this template is an actual instantiation
  /// that should be counted toward the maximum instantiation depth.
  bool isInstantiationRecord() const;
};

/// List of active code synthesis contexts.
///
/// This vector is treated as a stack. As synthesis of one entity requires
/// synthesis of another, additional contexts are pushed onto the stack.
SmallVector<CodeSynthesisContext, 16> CodeSynthesisContexts;

/// Specializations whose definitions are currently being instantiated.
llvm::DenseSet<std::pair<Decl *, unsigned>> InstantiatingSpecializations;

/// Non-dependent types used in templates that have already been instantiated
/// by some template instantiation.
llvm::DenseSet<QualType> InstantiatedNonDependentTypes;

/// Extra modules inspected when performing a lookup during a template
/// instantiation. Computed lazily.
SmallVector<Module*, 16> CodeSynthesisContextLookupModules;

/// Cache of additional modules that should be used for name lookup
/// within the current template instantiation. Computed lazily; use
/// getLookupModules() to get a complete set.
llvm::DenseSet<Module*> LookupModulesCache;

/// Get the set of additional modules that should be checked during
/// name lookup. A module and its imports become visible when instanting a
/// template defined within it.
llvm::DenseSet<Module*> &getLookupModules();

/// Map from the most recent declaration of a namespace to the most
/// recent visible declaration of that namespace.
llvm::DenseMap<NamedDecl*, NamedDecl*> VisibleNamespaceCache;

/// Whether we are in a SFINAE context that is not associated with
/// template instantiation.
///
/// This is used when setting up a SFINAE trap (\c see SFINAETrap) outside
/// of a template instantiation or template argument deduction.
bool InNonInstantiationSFINAEContext;

/// The number of \p CodeSynthesisContexts that are not template
/// instantiations and, therefore, should not be counted as part of the
/// instantiation depth.
///
/// When the instantiation depth reaches the user-configurable limit
/// \p LangOptions::InstantiationDepth we will abort instantiation.
// FIXME: Should we have a similar limit for other forms of synthesis?
unsigned NonInstantiationEntries;

/// The depth of the context stack at the point when the most recent
/// error or warning was produced.
///
/// This value is used to suppress printing of redundant context stacks
/// when there are multiple errors or warnings in the same instantiation.
// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
unsigned LastEmittedCodeSynthesisContextDepth = 0;

/// The template instantiation callbacks to trace or track
/// instantiations (objects can be chained).
///
/// This callbacks is used to print, trace or track template
/// instantiations as they are being constructed.
std::vector<std::unique_ptr<TemplateInstantiationCallback>>
    TemplateInstCallbacks;

/// The current index into pack expansion arguments that will be
/// used for substitution of parameter packs.
///
/// The pack expansion index will be -1 to indicate that parameter packs
/// should be instantiated as themselves. Otherwise, the index specifies
/// which argument within the parameter pack will be used for substitution.
int ArgumentPackSubstitutionIndex;

/// RAII object used to change the argument pack substitution index
/// within a \c Sema object.
///
/// See \c ArgumentPackSubstitutionIndex for more information.
class ArgumentPackSubstitutionIndexRAII {
  Sema &Self;
  int OldSubstitutionIndex;

public:
  ArgumentPackSubstitutionIndexRAII(Sema &Self, int NewSubstitutionIndex)
    : Self(Self), OldSubstitutionIndex(Self.ArgumentPackSubstitutionIndex) {
    Self.ArgumentPackSubstitutionIndex = NewSubstitutionIndex;
  }

  ~ArgumentPackSubstitutionIndexRAII() {
    Self.ArgumentPackSubstitutionIndex = OldSubstitutionIndex;
  }
};

friend class ArgumentPackSubstitutionRAII;

/// For each declaration that involved template argument deduction, the
/// set of diagnostics that were suppressed during that template argument
/// deduction.
///
/// FIXME: Serialize this structure to the AST file.
typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, 1> >
  SuppressedDiagnosticsMap;
SuppressedDiagnosticsMap SuppressedDiagnostics;

/// A stack object to be created when performing template
/// instantiation.
///
/// Construction of an object of type \c InstantiatingTemplate
/// pushes the current instantiation onto the stack of active
/// instantiations. If the size of this stack exceeds the maximum
/// number of recursive template instantiations, construction
/// produces an error and evaluates true.
///
/// Destruction of this object will pop the named instantiation off
/// the stack.
struct InstantiatingTemplate {
  /// Note that we are instantiating a class template,
  /// function template, variable template, alias template,
  /// or a member thereof.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        Decl *Entity,
                        SourceRange InstantiationRange = SourceRange());

  struct ExceptionSpecification {};
  /// Note that we are instantiating an exception specification
  /// of a function template.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionDecl *Entity, ExceptionSpecification,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument in a
  /// template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateParameter Param, TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting either explicitly-specified or
  /// deduced template arguments during function template argument deduction.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionTemplateDecl *FunctionTemplate,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        CodeSynthesisContext::SynthesisKind Kind,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template declaration.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ClassTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a variable template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        VarTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument for a function
  /// parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ParmVarDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting prior template arguments into a
  /// non-type parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        NonTypeTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are substituting prior template arguments into a
  /// template template parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        TemplateTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are checking the default template argument
  /// against the template parameter for a given template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        NamedDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  struct ConstraintsCheck {};
  /// \brief Note that we are checking the constraints associated with some
  /// constrained entity (a concept declaration or a template with associated
  /// constraints).
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintsCheck, NamedDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  struct ConstraintSubstitution {};
  /// \brief Note that we are checking a constraint expression associated
  /// with a template declaration or as part of the satisfaction check of a
  /// concept.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintSubstitution, NamedDecl *Template,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange);

  struct ConstraintNormalization {};
  /// \brief Note that we are normalizing a constraint expression.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ConstraintNormalization, NamedDecl *Template,
                        SourceRange InstantiationRange);

  struct ParameterMappingSubstitution {};
  /// \brief Note that we are subtituting into the parameter mapping of an
  /// atomic constraint during constraint normalization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ParameterMappingSubstitution, NamedDecl *Template,
                        SourceRange InstantiationRange);

  /// \brief Note that we are substituting template arguments into a part of
  /// a requirement of a requires expression.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        concepts::Requirement *Req,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// \brief Note that we are checking the satisfaction of the constraint
  /// expression inside of a nested requirement.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        concepts::NestedRequirement *Req, ConstraintsCheck,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we have finished instantiating this template.
  void Clear();

  ~InstantiatingTemplate() { Clear(); }

  /// Determines whether we have exceeded the maximum
  /// recursive template instantiations.
  bool isInvalid() const { return Invalid; }
30
←
Returning zero, which participates in a condition later→

  /// Determine whether we are already instantiating this
  /// specialization in some surrounding active instantiation.
  bool isAlreadyInstantiating() const { return AlreadyInstantiating; }

private:
  Sema &SemaRef;
  bool Invalid;
  bool AlreadyInstantiating;
  bool CheckInstantiationDepth(SourceLocation PointOfInstantiation,
                               SourceRange InstantiationRange);

  InstantiatingTemplate(
      Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
      SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
      Decl *Entity, NamedDecl *Template = nullptr,
      ArrayRef<TemplateArgument> TemplateArgs = None,
      sema::TemplateDeductionInfo *DeductionInfo = nullptr);

  InstantiatingTemplate(const InstantiatingTemplate&) = delete;

  InstantiatingTemplate&
  operator=(const InstantiatingTemplate&) = delete;
};

void pushCodeSynthesisContext(CodeSynthesisContext Ctx);
void popCodeSynthesisContext();

/// Determine whether we are currently performing template instantiation.
bool inTemplateInstantiation() const {
  return CodeSynthesisContexts.size() > NonInstantiationEntries;
}

void PrintContextStack() {
  if (!CodeSynthesisContexts.empty() &&
      CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
    PrintInstantiationStack();
    LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
  }
  if (PragmaAttributeCurrentTargetDecl)
    PrintPragmaAttributeInstantiationPoint();
}
void PrintInstantiationStack();

void PrintPragmaAttributeInstantiationPoint();

/// Determines whether we are currently in a context where
/// template argument substitution failures are not considered
/// errors.
///
/// \returns An empty \c Optional if we're not in a SFINAE context.
/// Otherwise, contains a pointer that, if non-NULL, contains the nearest
/// template-deduction context object, which can be used to capture
/// diagnostics that will be suppressed.
Optional<sema::TemplateDeductionInfo *> isSFINAEContext() const;

/// Determines whether we are currently in a context that
/// is not evaluated as per C++ [expr] p5.
bool isUnevaluatedContext() const {
  assert(!ExprEvalContexts.empty() &&((void)0)
         "Must be in an expression evaluation context")((void)0);
  return ExprEvalContexts.back().isUnevaluated();
}

/// RAII class used to determine whether SFINAE has
/// trapped any errors that occur during template argument
/// deduction.
class SFINAETrap {
  Sema &SemaRef;
  unsigned PrevSFINAEErrors;
  bool PrevInNonInstantiationSFINAEContext;
  bool PrevAccessCheckingSFINAE;
  bool PrevLastDiagnosticIgnored;

public:
  explicit SFINAETrap(Sema &SemaRef, bool AccessCheckingSFINAE = false)
    : SemaRef(SemaRef), PrevSFINAEErrors(SemaRef.NumSFINAEErrors),
      PrevInNonInstantiationSFINAEContext(
                                    SemaRef.InNonInstantiationSFINAEContext),
      PrevAccessCheckingSFINAE(SemaRef.AccessCheckingSFINAE),
      PrevLastDiagnosticIgnored(
          SemaRef.getDiagnostics().isLastDiagnosticIgnored())
  {
    if (!SemaRef.isSFINAEContext())
      SemaRef.InNonInstantiationSFINAEContext = true;
    SemaRef.AccessCheckingSFINAE = AccessCheckingSFINAE;
  }

  ~SFINAETrap() {
    SemaRef.NumSFINAEErrors = PrevSFINAEErrors;
    SemaRef.InNonInstantiationSFINAEContext
      = PrevInNonInstantiationSFINAEContext;
    SemaRef.AccessCheckingSFINAE = PrevAccessCheckingSFINAE;
    SemaRef.getDiagnostics().setLastDiagnosticIgnored(
        PrevLastDiagnosticIgnored);
  }

  /// Determine whether any SFINAE errors have been trapped.
  bool hasErrorOccurred() const {
    return SemaRef.NumSFINAEErrors > PrevSFINAEErrors;
  }
};

/// RAII class used to indicate that we are performing provisional
/// semantic analysis to determine the validity of a construct, so
/// typo-correction and diagnostics in the immediate context (not within
/// implicitly-instantiated templates) should be suppressed.
class TentativeAnalysisScope {
  Sema &SemaRef;
  // FIXME: Using a SFINAETrap for this is a hack.
  SFINAETrap Trap;
  bool PrevDisableTypoCorrection;
public:
  explicit TentativeAnalysisScope(Sema &SemaRef)
      : SemaRef(SemaRef), Trap(SemaRef, true),
        PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
    SemaRef.DisableTypoCorrection = true;
  }
  ~TentativeAnalysisScope() {
    SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
  }
};

/// The current instantiation scope used to store local
/// variables.
LocalInstantiationScope *CurrentInstantiationScope;

/// Tracks whether we are in a context where typo correction is
/// disabled.
bool DisableTypoCorrection;

/// The number of typos corrected by CorrectTypo.
unsigned TyposCorrected;

typedef llvm::SmallSet<SourceLocation, 2> SrcLocSet;
typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;

/// A cache containing identifiers for which typo correction failed and
/// their locations, so that repeated attempts to correct an identifier in a
/// given location are ignored if typo correction already failed for it.
IdentifierSourceLocations TypoCorrectionFailures;

/// Worker object for performing CFG-based warnings.
sema::AnalysisBasedWarnings AnalysisWarnings;
threadSafety::BeforeSet *ThreadSafetyDeclCache;

/// An entity for which implicit template instantiation is required.
///
/// The source location associated with the declaration is the first place in
/// the source code where the declaration was "used". It is not necessarily
/// the point of instantiation (which will be either before or after the
/// namespace-scope declaration that triggered this implicit instantiation),
/// However, it is the location that diagnostics should generally refer to,
/// because users will need to know what code triggered the instantiation.
typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;

/// The queue of implicit template instantiations that are required
/// but have not yet been performed.
std::deque<PendingImplicitInstantiation> PendingInstantiations;

/// Queue of implicit template instantiations that cannot be performed
/// eagerly.
SmallVector<PendingImplicitInstantiation, 1> LateParsedInstantiations;

class GlobalEagerInstantiationScope {
public:
  GlobalEagerInstantiationScope(Sema &S, bool Enabled)
      : S(S), Enabled(Enabled) {
    if (!Enabled) return;

    SavedPendingInstantiations.swap(S.PendingInstantiations);
    SavedVTableUses.swap(S.VTableUses);
  }

  void perform() {
    if (Enabled) {
      S.DefineUsedVTables();
      S.PerformPendingInstantiations();
    }
  }

  ~GlobalEagerInstantiationScope() {
    if (!Enabled) return;

    // Restore the set of pending vtables.
    assert(S.VTableUses.empty() &&((void)0)
           "VTableUses should be empty before it is discarded.")((void)0);
    S.VTableUses.swap(SavedVTableUses);

    // Restore the set of pending implicit instantiations.
    if (S.TUKind != TU_Prefix || !S.LangOpts.PCHInstantiateTemplates) {
      assert(S.PendingInstantiations.empty() &&((void)0)
             "PendingInstantiations should be empty before it is discarded.")((void)0);
      S.PendingInstantiations.swap(SavedPendingInstantiations);
    } else {
      // Template instantiations in the PCH may be delayed until the TU.
      S.PendingInstantiations.swap(SavedPendingInstantiations);
      S.PendingInstantiations.insert(S.PendingInstantiations.end(),
                                     SavedPendingInstantiations.begin(),
                                     SavedPendingInstantiations.end());
    }
  }

private:
  Sema &S;
  SmallVector<VTableUse, 16> SavedVTableUses;
  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
  bool Enabled;
};

/// The queue of implicit template instantiations that are required
/// and must be performed within the current local scope.
///
/// This queue is only used for member functions of local classes in
/// templates, which must be instantiated in the same scope as their
/// enclosing function, so that they can reference function-local
/// types, static variables, enumerators, etc.
std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;

class LocalEagerInstantiationScope {
public:
  LocalEagerInstantiationScope(Sema &S) : S(S) {
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

  void perform() { S.PerformPendingInstantiations(/*LocalOnly=*/true); }

  ~LocalEagerInstantiationScope() {
    assert(S.PendingLocalImplicitInstantiations.empty() &&((void)0)
           "there shouldn't be any pending local implicit instantiations")((void)0);
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

private:
  Sema &S;
  std::deque<PendingImplicitInstantiation>
      SavedPendingLocalImplicitInstantiations;
};

/// A helper class for building up ExtParameterInfos.
class ExtParameterInfoBuilder {
  SmallVector<FunctionProtoType::ExtParameterInfo, 16> Infos;
  bool HasInteresting = false;

public:
  /// Set the ExtParameterInfo for the parameter at the given index,
  ///
  void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
    assert(Infos.size() <= index)((void)0);
    Infos.resize(index);
    Infos.push_back(info);

    if (!HasInteresting)
      HasInteresting = (info != FunctionProtoType::ExtParameterInfo());
  }

  /// Return a pointer (suitable for setting in an ExtProtoInfo) to the
  /// ExtParameterInfo array we've built up.
  const FunctionProtoType::ExtParameterInfo *
  getPointerOrNull(unsigned numParams) {
    if (!HasInteresting) return nullptr;
    Infos.resize(numParams);
    return Infos.data();
  }
};

void PerformPendingInstantiations(bool LocalOnly = false);

TypeSourceInfo *SubstType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity,
                          bool AllowDeducedTST = false);

QualType SubstType(QualType T,
                   const MultiLevelTemplateArgumentList &TemplateArgs,
                   SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstType(TypeLoc TL,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstFunctionDeclType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                      SourceLocation Loc,
                                      DeclarationName Entity,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals);
void SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                        const MultiLevelTemplateArgumentList &Args);
bool SubstExceptionSpec(SourceLocation Loc,
                        FunctionProtoType::ExceptionSpecInfo &ESI,
                        SmallVectorImpl<QualType> &ExceptionStorage,
                        const MultiLevelTemplateArgumentList &Args);
ParmVarDecl *SubstParmVarDecl(ParmVarDecl *D,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                              int indexAdjustment,
                              Optional<unsigned> NumExpansions,
                              bool ExpectParameterPack);
bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
                    const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
                    const MultiLevelTemplateArgumentList &TemplateArgs,
                    SmallVectorImpl<QualType> &ParamTypes,
                    SmallVectorImpl<ParmVarDecl *> *OutParams,
                    ExtParameterInfoBuilder &ParamInfos);
ExprResult SubstExpr(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

/// Substitute the given template arguments into a list of
/// expressions, expanding pack expansions if required.
///
/// \param Exprs The list of expressions to substitute into.
///
/// \param IsCall Whether this is some form of call, in which case
/// default arguments will be dropped.
///
/// \param TemplateArgs The set of template arguments to substitute.
///
/// \param Outputs Will receive all of the substituted arguments.
///
/// \returns true if an error occurred, false otherwise.
bool SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall,
                const MultiLevelTemplateArgumentList &TemplateArgs,
                SmallVectorImpl<Expr *> &Outputs);

StmtResult SubstStmt(Stmt *S,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

TemplateParameterList *
SubstTemplateParams(TemplateParameterList *Params, DeclContext *Owner,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

bool
SubstTemplateArguments(ArrayRef<TemplateArgumentLoc> Args,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       TemplateArgumentListInfo &Outputs);


Decl *SubstDecl(Decl *D, DeclContext *Owner,
                const MultiLevelTemplateArgumentList &TemplateArgs);

/// Substitute the name and return type of a defaulted 'operator<=>' to form
/// an implicit 'operator=='.
FunctionDecl *SubstSpaceshipAsEqualEqual(CXXRecordDecl *RD,
                                         FunctionDecl *Spaceship);

ExprResult SubstInitializer(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     bool CXXDirectInit);

bool
SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                    CXXRecordDecl *Pattern,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

bool
InstantiateClass(SourceLocation PointOfInstantiation,
                 CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                 const MultiLevelTemplateArgumentList &TemplateArgs,
                 TemplateSpecializationKind TSK,
                 bool Complain = true);

bool InstantiateEnum(SourceLocation PointOfInstantiation,
                     EnumDecl *Instantiation, EnumDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK);

bool InstantiateInClassInitializer(
    SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
    FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs);

struct LateInstantiatedAttribute {
  const Attr *TmplAttr;
  LocalInstantiationScope *Scope;
  Decl *NewDecl;

  LateInstantiatedAttribute(const Attr *A, LocalInstantiationScope *S,
                            Decl *D)
    : TmplAttr(A), Scope(S), NewDecl(D)
  { }
};
typedef SmallVector<LateInstantiatedAttribute, 16> LateInstantiatedAttrVec;

void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                      const Decl *Pattern, Decl *Inst,
                      LateInstantiatedAttrVec *LateAttrs = nullptr,
                      LocalInstantiationScope *OuterMostScope = nullptr);

void
InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
                        const Decl *Pattern, Decl *Inst,
                        LateInstantiatedAttrVec *LateAttrs = nullptr,
                        LocalInstantiationScope *OuterMostScope = nullptr);

void InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor);

bool usesPartialOrExplicitSpecialization(
    SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);

bool
InstantiateClassTemplateSpecialization(SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                         TemplateSpecializationKind TSK,
                         bool Complain = true);

void InstantiateClassMembers(SourceLocation PointOfInstantiation,
                             CXXRecordDecl *Instantiation,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                             TemplateSpecializationKind TSK);

void InstantiateClassTemplateSpecializationMembers(
                                        SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                                              TemplateSpecializationKind TSK);

NestedNameSpecifierLoc
SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
                         const MultiLevelTemplateArgumentList &TemplateArgs);

DeclarationNameInfo
SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
                         const MultiLevelTemplateArgumentList &TemplateArgs);
TemplateName
SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, TemplateName Name,
                  SourceLocation Loc,
                  const MultiLevelTemplateArgumentList &TemplateArgs);
bool Subst(const TemplateArgumentLoc *Args, unsigned NumArgs,
           TemplateArgumentListInfo &Result,
           const MultiLevelTemplateArgumentList &TemplateArgs);

bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
                                ParmVarDecl *Param);
void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
                              FunctionDecl *Function);
bool CheckInstantiatedFunctionTemplateConstraints(
    SourceLocation PointOfInstantiation, FunctionDecl *Decl,
    ArrayRef<TemplateArgument> TemplateArgs,
    ConstraintSatisfaction &Satisfaction);
FunctionDecl *InstantiateFunctionDeclaration(FunctionTemplateDecl *FTD,
                                             const TemplateArgumentList *Args,
                                             SourceLocation Loc);
void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
                                   FunctionDecl *Function,
                                   bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);
VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
    VarTemplateDecl *VarTemplate, VarDecl *FromVar,
    const TemplateArgumentList &TemplateArgList,
    const TemplateArgumentListInfo &TemplateArgsInfo,
    SmallVectorImpl<TemplateArgument> &Converted,
    SourceLocation PointOfInstantiation,
    LateInstantiatedAttrVec *LateAttrs = nullptr,
    LocalInstantiationScope *StartingScope = nullptr);
VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
    VarTemplateSpecializationDecl *VarSpec, VarDecl *PatternDecl,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void
BuildVariableInstantiation(VarDecl *NewVar, VarDecl *OldVar,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                           LateInstantiatedAttrVec *LateAttrs,
                           DeclContext *Owner,
                           LocalInstantiationScope *StartingScope,
                           bool InstantiatingVarTemplate = false,
                           VarTemplateSpecializationDecl *PrevVTSD = nullptr);

void InstantiateVariableInitializer(
    VarDecl *Var, VarDecl *OldVar,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
                                   VarDecl *Var, bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);

void InstantiateMemInitializers(CXXConstructorDecl *New,
                                const CXXConstructorDecl *Tmpl,
                          const MultiLevelTemplateArgumentList &TemplateArgs);

NamedDecl *FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
                        const MultiLevelTemplateArgumentList &TemplateArgs,
                        bool FindingInstantiatedContext = false);
DeclContext *FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
                        const MultiLevelTemplateArgumentList &TemplateArgs);

// Objective-C declarations.
enum ObjCContainerKind {
  OCK_None = -1,
  OCK_Interface = 0,
  OCK_Protocol,
  OCK_Category,
  OCK_ClassExtension,
  OCK_Implementation,
  OCK_CategoryImplementation
};
ObjCContainerKind getObjCContainerKind() const;

DeclResult actOnObjCTypeParam(Scope *S,
                              ObjCTypeParamVariance variance,
                              SourceLocation varianceLoc,
                              unsigned index,
                              IdentifierInfo *paramName,
                              SourceLocation paramLoc,
                              SourceLocation colonLoc,
                              ParsedType typeBound);

ObjCTypeParamList *actOnObjCTypeParamList(Scope *S, SourceLocation lAngleLoc,
                                          ArrayRef<Decl *> typeParams,
                                          SourceLocation rAngleLoc);
void popObjCTypeParamList(Scope *S, ObjCTypeParamList *typeParamList);

Decl *ActOnStartClassInterface(
    Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *SuperName, SourceLocation SuperLoc,
    ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

void ActOnSuperClassOfClassInterface(Scope *S,
                                     SourceLocation AtInterfaceLoc,
                                     ObjCInterfaceDecl *IDecl,
                                     IdentifierInfo *ClassName,
                                     SourceLocation ClassLoc,
                                     IdentifierInfo *SuperName,
                                     SourceLocation SuperLoc,
                                     ArrayRef<ParsedType> SuperTypeArgs,
                                     SourceRange SuperTypeArgsRange);

void ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
                             SmallVectorImpl<SourceLocation> &ProtocolLocs,
                             IdentifierInfo *SuperName,
                             SourceLocation SuperLoc);

Decl *ActOnCompatibilityAlias(
                  SourceLocation AtCompatibilityAliasLoc,
                  IdentifierInfo *AliasName,  SourceLocation AliasLocation,
                  IdentifierInfo *ClassName, SourceLocation ClassLocation);

bool CheckForwardProtocolDeclarationForCircularDependency(
  IdentifierInfo *PName,
  SourceLocation &PLoc, SourceLocation PrevLoc,
  const ObjCList<ObjCProtocolDecl> &PList);

Decl *ActOnStartProtocolInterface(
    SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
    SourceLocation ProtocolLoc, Decl *const *ProtoRefNames,
    unsigned NumProtoRefs, const SourceLocation *ProtoLocs,
    SourceLocation EndProtoLoc, const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryInterface(
    SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

Decl *ActOnStartClassImplementation(SourceLocation AtClassImplLoc,
                                    IdentifierInfo *ClassName,
                                    SourceLocation ClassLoc,
                                    IdentifierInfo *SuperClassname,
                                    SourceLocation SuperClassLoc,
                                    const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryImplementation(SourceLocation AtCatImplLoc,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassLoc,
                                       IdentifierInfo *CatName,
                                       SourceLocation CatLoc,
                                       const ParsedAttributesView &AttrList);

DeclGroupPtrTy ActOnFinishObjCImplementation(Decl *ObjCImpDecl,
                                             ArrayRef<Decl *> Decls);

DeclGroupPtrTy ActOnForwardClassDeclaration(SourceLocation Loc,
                 IdentifierInfo **IdentList,
                 SourceLocation *IdentLocs,
                 ArrayRef<ObjCTypeParamList *> TypeParamLists,
                 unsigned NumElts);

DeclGroupPtrTy
ActOnForwardProtocolDeclaration(SourceLocation AtProtoclLoc,
                                ArrayRef<IdentifierLocPair> IdentList,
                                const ParsedAttributesView &attrList);

void FindProtocolDeclaration(bool WarnOnDeclarations, bool ForObjCContainer,
                             ArrayRef<IdentifierLocPair> ProtocolId,
                             SmallVectorImpl<Decl *> &Protocols);

void DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
                                  SourceLocation ProtocolLoc,
                                  IdentifierInfo *TypeArgId,
                                  SourceLocation TypeArgLoc,
                                  bool SelectProtocolFirst = false);

/// Given a list of identifiers (and their locations), resolve the
/// names to either Objective-C protocol qualifiers or type
/// arguments, as appropriate.
void actOnObjCTypeArgsOrProtocolQualifiers(
       Scope *S,
       ParsedType baseType,
       SourceLocation lAngleLoc,
       ArrayRef<IdentifierInfo *> identifiers,
       ArrayRef<SourceLocation> identifierLocs,
       SourceLocation rAngleLoc,
       SourceLocation &typeArgsLAngleLoc,
       SmallVectorImpl<ParsedType> &typeArgs,
       SourceLocation &typeArgsRAngleLoc,
       SourceLocation &protocolLAngleLoc,
       SmallVectorImpl<Decl *> &protocols,
       SourceLocation &protocolRAngleLoc,
       bool warnOnIncompleteProtocols);

/// Build a an Objective-C protocol-qualified 'id' type where no
/// base type was specified.
TypeResult actOnObjCProtocolQualifierType(
             SourceLocation lAngleLoc,
             ArrayRef<Decl *> protocols,
             ArrayRef<SourceLocation> protocolLocs,
             SourceLocation rAngleLoc);

/// Build a specialized and/or protocol-qualified Objective-C type.
TypeResult actOnObjCTypeArgsAndProtocolQualifiers(
             Scope *S,
             SourceLocation Loc,
             ParsedType BaseType,
             SourceLocation TypeArgsLAngleLoc,
             ArrayRef<ParsedType> TypeArgs,
             SourceLocation TypeArgsRAngleLoc,
             SourceLocation ProtocolLAngleLoc,
             ArrayRef<Decl *> Protocols,
             ArrayRef<SourceLocation> ProtocolLocs,
             SourceLocation ProtocolRAngleLoc);

/// Build an Objective-C type parameter type.
QualType BuildObjCTypeParamType(const ObjCTypeParamDecl *Decl,
                                SourceLocation ProtocolLAngleLoc,
                                ArrayRef<ObjCProtocolDecl *> Protocols,
                                ArrayRef<SourceLocation> ProtocolLocs,
                                SourceLocation ProtocolRAngleLoc,
                                bool FailOnError = false);

/// Build an Objective-C object pointer type.
QualType BuildObjCObjectType(QualType BaseType,
                             SourceLocation Loc,
                             SourceLocation TypeArgsLAngleLoc,
                             ArrayRef<TypeSourceInfo *> TypeArgs,
                             SourceLocation TypeArgsRAngleLoc,
                             SourceLocation ProtocolLAngleLoc,
                             ArrayRef<ObjCProtocolDecl *> Protocols,
                             ArrayRef<SourceLocation> ProtocolLocs,
                             SourceLocation ProtocolRAngleLoc,
                             bool FailOnError = false);

/// Ensure attributes are consistent with type.
/// \param [in, out] Attributes The attributes to check; they will
/// be modified to be consistent with \p PropertyTy.
void CheckObjCPropertyAttributes(Decl *PropertyPtrTy,
                                 SourceLocation Loc,
                                 unsigned &Attributes,
                                 bool propertyInPrimaryClass);

/// Process the specified property declaration and create decls for the
/// setters and getters as needed.
/// \param property The property declaration being processed
void ProcessPropertyDecl(ObjCPropertyDecl *property);


void DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
                              ObjCPropertyDecl *SuperProperty,
                              const IdentifierInfo *Name,
                              bool OverridingProtocolProperty);

void DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
                                      ObjCInterfaceDecl *ID);

Decl *ActOnAtEnd(Scope *S, SourceRange AtEnd,
                 ArrayRef<Decl *> allMethods = None,
                 ArrayRef<DeclGroupPtrTy> allTUVars = None);

Decl *ActOnProperty(Scope *S, SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD, ObjCDeclSpec &ODS,
                    Selector GetterSel, Selector SetterSel,
                    tok::ObjCKeywordKind MethodImplKind,
                    DeclContext *lexicalDC = nullptr);

Decl *ActOnPropertyImplDecl(Scope *S,
                            SourceLocation AtLoc,
                            SourceLocation PropertyLoc,
                            bool ImplKind,
                            IdentifierInfo *PropertyId,
                            IdentifierInfo *PropertyIvar,
                            SourceLocation PropertyIvarLoc,
                            ObjCPropertyQueryKind QueryKind);

enum ObjCSpecialMethodKind {
  OSMK_None,
  OSMK_Alloc,
  OSMK_New,
  OSMK_Copy,
  OSMK_RetainingInit,
  OSMK_NonRetainingInit
};

struct ObjCArgInfo {
  IdentifierInfo *Name;
  SourceLocation NameLoc;
  // The Type is null if no type was specified, and the DeclSpec is invalid
  // in this case.
  ParsedType Type;
  ObjCDeclSpec DeclSpec;

  /// ArgAttrs - Attribute list for this argument.
  ParsedAttributesView ArgAttrs;
};

Decl *ActOnMethodDeclaration(
    Scope *S,
    SourceLocation BeginLoc, // location of the + or -.
    SourceLocation EndLoc,   // location of the ; or {.
    tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
    ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
    // optional arguments. The number of types/arguments is obtained
    // from the Sel.getNumArgs().
    ObjCArgInfo *ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
    unsigned CNumArgs, // c-style args
    const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodImplKind,
    bool isVariadic, bool MethodDefinition);

ObjCMethodDecl *LookupMethodInQualifiedType(Selector Sel,
                                            const ObjCObjectPointerType *OPT,
                                            bool IsInstance);
ObjCMethodDecl *LookupMethodInObjectType(Selector Sel, QualType Ty,
                                         bool IsInstance);

bool CheckARCMethodDecl(ObjCMethodDecl *method);
bool inferObjCARCLifetime(ValueDecl *decl);

void deduceOpenCLAddressSpace(ValueDecl *decl);

ExprResult
HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
                          Expr *BaseExpr,
                          SourceLocation OpLoc,
                          DeclarationName MemberName,
                          SourceLocation MemberLoc,
                          SourceLocation SuperLoc, QualType SuperType,
                          bool Super);

ExprResult
ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
                          IdentifierInfo &propertyName,
                          SourceLocation receiverNameLoc,
                          SourceLocation propertyNameLoc);

ObjCMethodDecl *tryCaptureObjCSelf(SourceLocation Loc);

/// Describes the kind of message expression indicated by a message
/// send that starts with an identifier.
enum ObjCMessageKind {
  /// The message is sent to 'super'.
  ObjCSuperMessage,
  /// The message is an instance message.
  ObjCInstanceMessage,
  /// The message is a class message, and the identifier is a type
  /// name.
  ObjCClassMessage
};

ObjCMessageKind getObjCMessageKind(Scope *S,
                                   IdentifierInfo *Name,
                                   SourceLocation NameLoc,
                                   bool IsSuper,
                                   bool HasTrailingDot,
                                   ParsedType &ReceiverType);

ExprResult ActOnSuperMessage(Scope *S, SourceLocation SuperLoc,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
                             QualType ReceiverType,
                             SourceLocation SuperLoc,
                             Selector Sel,
                             ObjCMethodDecl *Method,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args,
                             bool isImplicit = false);

ExprResult BuildClassMessageImplicit(QualType ReceiverType,
                                     bool isSuperReceiver,
                                     SourceLocation Loc,
                                     Selector Sel,
                                     ObjCMethodDecl *Method,
                                     MultiExprArg Args);

ExprResult ActOnClassMessage(Scope *S,
                             ParsedType Receiver,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildInstanceMessage(Expr *Receiver,
                                QualType ReceiverType,
                                SourceLocation SuperLoc,
                                Selector Sel,
                                ObjCMethodDecl *Method,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args,
                                bool isImplicit = false);

ExprResult BuildInstanceMessageImplicit(Expr *Receiver,
                                        QualType ReceiverType,
                                        SourceLocation Loc,
                                        Selector Sel,
                                        ObjCMethodDecl *Method,
                                        MultiExprArg Args);

ExprResult ActOnInstanceMessage(Scope *S,
                                Expr *Receiver,
                                Selector Sel,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args);

ExprResult BuildObjCBridgedCast(SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                TypeSourceInfo *TSInfo,
                                Expr *SubExpr);

ExprResult ActOnObjCBridgedCast(Scope *S,
                                SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                ParsedType Type,
                                SourceLocation RParenLoc,
                                Expr *SubExpr);

void CheckTollFreeBridgeCast(QualType castType, Expr *castExpr);

void CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr);

bool CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
                                   CastKind &Kind);

bool checkObjCBridgeRelatedComponents(SourceLocation Loc,
                                      QualType DestType, QualType SrcType,
                                      ObjCInterfaceDecl *&RelatedClass,
                                      ObjCMethodDecl *&ClassMethod,
                                      ObjCMethodDecl *&InstanceMethod,
                                      TypedefNameDecl *&TDNDecl,
                                      bool CfToNs, bool Diagnose = true);

bool CheckObjCBridgeRelatedConversions(SourceLocation Loc,
                                       QualType DestType, QualType SrcType,
                                       Expr *&SrcExpr, bool Diagnose = true);

bool CheckConversionToObjCLiteral(QualType DstType, Expr *&SrcExpr,
                                  bool Diagnose = true);

bool checkInitMethod(ObjCMethodDecl *method, QualType receiverTypeIfCall);

/// Check whether the given new method is a valid override of the
/// given overridden method, and set any properties that should be inherited.
void CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
                             const ObjCMethodDecl *Overridden);

/// Describes the compatibility of a result type with its method.
enum ResultTypeCompatibilityKind {
  RTC_Compatible,
  RTC_Incompatible,
  RTC_Unknown
};

void CheckObjCMethodDirectOverrides(ObjCMethodDecl *method,
                                    ObjCMethodDecl *overridden);

void CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
                              ObjCInterfaceDecl *CurrentClass,
                              ResultTypeCompatibilityKind RTC);

enum PragmaOptionsAlignKind {
  POAK_Native,  // #pragma options align=native
  POAK_Natural, // #pragma options align=natural
  POAK_Packed,  // #pragma options align=packed
  POAK_Power,   // #pragma options align=power
  POAK_Mac68k,  // #pragma options align=mac68k
  POAK_Reset    // #pragma options align=reset
};

/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
void ActOnPragmaClangSection(SourceLocation PragmaLoc,
                             PragmaClangSectionAction Action,
                             PragmaClangSectionKind SecKind, StringRef SecName);

/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
                             SourceLocation PragmaLoc);

/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
                     StringRef SlotLabel, Expr *Alignment);

enum class PragmaAlignPackDiagnoseKind {
  NonDefaultStateAtInclude,
  ChangedStateAtExit
};

void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
                                       SourceLocation IncludeLoc);
void DiagnoseUnterminatedPragmaAlignPack();

/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on|off].
void ActOnPragmaMSStruct(PragmaMSStructKind Kind);

/// ActOnPragmaMSComment - Called on well formed
/// \#pragma comment(kind, "arg").
void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
                          StringRef Arg);

/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
/// pointers_to_members(representation method[, general purpose
/// representation]).
void ActOnPragmaMSPointersToMembers(
    LangOptions::PragmaMSPointersToMembersKind Kind,
    SourceLocation PragmaLoc);

/// Called on well formed \#pragma vtordisp().
void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
                           SourceLocation PragmaLoc,
                           MSVtorDispMode Value);

enum PragmaSectionKind {
  PSK_DataSeg,
  PSK_BSSSeg,
  PSK_ConstSeg,
  PSK_CodeSeg,
};

bool UnifySection(StringRef SectionName, int SectionFlags,
                  NamedDecl *TheDecl);
bool UnifySection(StringRef SectionName,
                  int SectionFlags,
                  SourceLocation PragmaSectionLocation);

/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
                      PragmaMsStackAction Action,
                      llvm::StringRef StackSlotLabel,
                      StringLiteral *SegmentName,
                      llvm::StringRef PragmaName);

/// Called on well formed \#pragma section().
void ActOnPragmaMSSection(SourceLocation PragmaLocation,
                          int SectionFlags, StringLiteral *SegmentName);

/// Called on well-formed \#pragma init_seg().
void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
                          StringLiteral *SegmentName);

/// Called on #pragma clang __debug dump II
void ActOnPragmaDump(Scope *S, SourceLocation Loc, IdentifierInfo *II);

/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
                               StringRef Value);

/// Are precise floating point semantics currently enabled?
bool isPreciseFPEnabled() {
  return !CurFPFeatures.getAllowFPReassociate() &&
         !CurFPFeatures.getNoSignedZero() &&
         !CurFPFeatures.getAllowReciprocal() &&
         !CurFPFeatures.getAllowApproxFunc();
}

/// ActOnPragmaFloatControl - Call on well-formed \#pragma float_control
void ActOnPragmaFloatControl(SourceLocation Loc, PragmaMsStackAction Action,
                             PragmaFloatControlKind Value);

/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
void ActOnPragmaUnused(const Token &Identifier,
                       Scope *curScope,
                       SourceLocation PragmaLoc);

/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
void ActOnPragmaVisibility(const IdentifierInfo* VisType,
                           SourceLocation PragmaLoc);

NamedDecl *DeclClonePragmaWeak(NamedDecl *ND, IdentifierInfo *II,
                               SourceLocation Loc);
void DeclApplyPragmaWeak(Scope *S, NamedDecl *ND, WeakInfo &W);

/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
void ActOnPragmaWeakID(IdentifierInfo* WeakName,
                       SourceLocation PragmaLoc,
                       SourceLocation WeakNameLoc);

/// ActOnPragmaRedefineExtname - Called on well formed
/// \#pragma redefine_extname oldname newname.
void ActOnPragmaRedefineExtname(IdentifierInfo* WeakName,
                                IdentifierInfo* AliasName,
                                SourceLocation PragmaLoc,
                                SourceLocation WeakNameLoc,
                                SourceLocation AliasNameLoc);

/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
void ActOnPragmaWeakAlias(IdentifierInfo* WeakName,
                          IdentifierInfo* AliasName,
                          SourceLocation PragmaLoc,
                          SourceLocation WeakNameLoc,
                          SourceLocation AliasNameLoc);

/// ActOnPragmaFPContract - Called on well formed
/// \#pragma {STDC,OPENCL} FP_CONTRACT and
/// \#pragma clang fp contract
void ActOnPragmaFPContract(SourceLocation Loc, LangOptions::FPModeKind FPC);

/// Called on well formed
/// \#pragma clang fp reassociate
void ActOnPragmaFPReassociate(SourceLocation Loc, bool IsEnabled);

/// ActOnPragmaFenvAccess - Called on well formed
/// \#pragma STDC FENV_ACCESS
void ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled);

/// Called on well formed '\#pragma clang fp' that has option 'exceptions'.
void ActOnPragmaFPExceptions(SourceLocation Loc,
                             LangOptions::FPExceptionModeKind);

/// Called to set constant rounding mode for floating point operations.
void setRoundingMode(SourceLocation Loc, llvm::RoundingMode);

/// Called to set exception behavior for floating point operations.
void setExceptionMode(SourceLocation Loc, LangOptions::FPExceptionModeKind);

/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
void AddAlignmentAttributesForRecord(RecordDecl *RD);

/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
void AddMsStructLayoutForRecord(RecordDecl *RD);

/// PushNamespaceVisibilityAttr - Note that we've entered a
/// namespace with a visibility attribute.
void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
                                 SourceLocation Loc);

/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
/// add an appropriate visibility attribute.
void AddPushedVisibilityAttribute(Decl *RD);

/// PopPragmaVisibility - Pop the top element of the visibility stack; used
/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);

/// FreeVisContext - Deallocate and null out VisContext.
void FreeVisContext();

/// AddCFAuditedAttribute - Check whether we're currently within
/// '\#pragma clang arc_cf_code_audited' and, if so, consider adding
/// the appropriate attribute.
void AddCFAuditedAttribute(Decl *D);

void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
                                   SourceLocation PragmaLoc,
                                   attr::ParsedSubjectMatchRuleSet Rules);
void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
                                   const IdentifierInfo *Namespace);

/// Called on well-formed '\#pragma clang attribute pop'.
void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
                             const IdentifierInfo *Namespace);

/// Adds the attributes that have been specified using the
/// '\#pragma clang attribute push' directives to the given declaration.
void AddPragmaAttributes(Scope *S, Decl *D);

void DiagnoseUnterminatedPragmaAttribute();

/// Called on well formed \#pragma clang optimize.
void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);

/// Get the location for the currently active "\#pragma clang optimize
/// off". If this location is invalid, then the state of the pragma is "on".
SourceLocation getOptimizeOffPragmaLocation() const {
  return OptimizeOffPragmaLocation;
}

/// Only called on function definitions; if there is a pragma in scope
/// with the effect of a range-based optnone, consider marking the function
/// with attribute optnone.
void AddRangeBasedOptnone(FunctionDecl *FD);

/// Adds the 'optnone' attribute to the function declaration if there
/// are no conflicts; Loc represents the location causing the 'optnone'
/// attribute to be added (usually because of a pragma).
void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);

/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                    bool IsPackExpansion);
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, TypeSourceInfo *T,
                    bool IsPackExpansion);

/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
/// declaration.
void AddAssumeAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                          Expr *OE);

/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
/// declaration.
void AddAllocAlignAttr(Decl *D, const AttributeCommonInfo &CI,
                       Expr *ParamExpr);

/// AddAlignValueAttr - Adds an align_value attribute to a particular
/// declaration.
void AddAlignValueAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E);

/// AddAnnotationAttr - Adds an annotation Annot with Args arguments to D.
void AddAnnotationAttr(Decl *D, const AttributeCommonInfo &CI,
                       StringRef Annot, MutableArrayRef<Expr *> Args);

/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
/// declaration.
void AddLaunchBoundsAttr(Decl *D, const AttributeCommonInfo &CI,
                         Expr *MaxThreads, Expr *MinBlocks);

/// AddModeAttr - Adds a mode attribute to a particular declaration.
void AddModeAttr(Decl *D, const AttributeCommonInfo &CI, IdentifierInfo *Name,
                 bool InInstantiation = false);

void AddParameterABIAttr(Decl *D, const AttributeCommonInfo &CI,
                         ParameterABI ABI);

enum class RetainOwnershipKind {NS, CF, OS};
void AddXConsumedAttr(Decl *D, const AttributeCommonInfo &CI,
                      RetainOwnershipKind K, bool IsTemplateInstantiation);

/// addAMDGPUFlatWorkGroupSizeAttr - Adds an amdgpu_flat_work_group_size
/// attribute to a particular declaration.
void addAMDGPUFlatWorkGroupSizeAttr(Decl *D, const AttributeCommonInfo &CI,
                                    Expr *Min, Expr *Max);

/// addAMDGPUWavePersEUAttr - Adds an amdgpu_waves_per_eu attribute to a
/// particular declaration.
void addAMDGPUWavesPerEUAttr(Decl *D, const AttributeCommonInfo &CI,
                             Expr *Min, Expr *Max);

bool checkNSReturnsRetainedReturnType(SourceLocation loc, QualType type);

//===--------------------------------------------------------------------===//
// C++ Coroutines TS
//
bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
                             StringRef Keyword);
ExprResult ActOnCoawaitExpr(Scope *S, SourceLocation KwLoc, Expr *E);
ExprResult ActOnCoyieldExpr(Scope *S, SourceLocation KwLoc, Expr *E);
StmtResult ActOnCoreturnStmt(Scope *S, SourceLocation KwLoc, Expr *E);

ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                    bool IsImplicit = false);
ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                      UnresolvedLookupExpr* Lookup);
ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
                             bool IsImplicit = false);
StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
bool buildCoroutineParameterMoves(SourceLocation Loc);
VarDecl *buildCoroutinePromise(SourceLocation Loc);
void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
                                         SourceLocation FuncLoc);
/// Check that the expression co_await promise.final_suspend() shall not be
/// potentially-throwing.
bool checkFinalSuspendNoThrow(const Stmt *FinalSuspend);

//===--------------------------------------------------------------------===//
// OpenMP directives and clauses.
//
10220private:
void *VarDataSharingAttributesStack;

struct DeclareTargetContextInfo {
  struct MapInfo {
    OMPDeclareTargetDeclAttr::MapTypeTy MT;
    SourceLocation Loc;
  };
  /// Explicitly listed variables and functions in a 'to' or 'link' clause.
  llvm::DenseMap<NamedDecl *, MapInfo> ExplicitlyMapped;

  /// The 'device_type' as parsed from the clause.
  OMPDeclareTargetDeclAttr::DevTypeTy DT = OMPDeclareTargetDeclAttr::DT_Any;

  /// The directive kind, `begin declare target` or `declare target`.
  OpenMPDirectiveKind Kind;

  /// The directive location.
  SourceLocation Loc;

  DeclareTargetContextInfo(OpenMPDirectiveKind Kind, SourceLocation Loc)
      : Kind(Kind), Loc(Loc) {}
};

/// Number of nested '#pragma omp declare target' directives.
SmallVector<DeclareTargetContextInfo, 4> DeclareTargetNesting;

/// Initialization of data-sharing attributes stack.
void InitDataSharingAttributesStack();
void DestroyDataSharingAttributesStack();
ExprResult
VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
                                      bool StrictlyPositive = true,
                                      bool SuppressExprDiags = false);
/// Returns OpenMP nesting level for current directive.
unsigned getOpenMPNestingLevel() const;

/// Adjusts the function scopes index for the target-based regions.
void adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
                                  unsigned Level) const;

/// Returns the number of scopes associated with the construct on the given
/// OpenMP level.
int getNumberOfConstructScopes(unsigned Level) const;

/// Push new OpenMP function region for non-capturing function.
void pushOpenMPFunctionRegion();

/// Pop OpenMP function region for non-capturing function.
void popOpenMPFunctionRegion(const sema::FunctionScopeInfo *OldFSI);

/// Analyzes and checks a loop nest for use by a loop transformation.
///
/// \param Kind          The loop transformation directive kind.
/// \param NumLoops      How many nested loops the directive is expecting.
/// \param AStmt         Associated statement of the transformation directive.
/// \param LoopHelpers   [out] The loop analysis result.
/// \param Body          [out] The body code nested in \p NumLoops loop.
/// \param OriginalInits [out] Collection of statements and declarations that
///                      must have been executed/declared before entering the
///                      loop.
///
/// \return Whether there was any error.
bool checkTransformableLoopNest(
    OpenMPDirectiveKind Kind, Stmt *AStmt, int NumLoops,
    SmallVectorImpl<OMPLoopBasedDirective::HelperExprs> &LoopHelpers,
    Stmt *&Body,
    SmallVectorImpl<SmallVector<llvm::PointerUnion<Stmt *, Decl *>, 0>>
        &OriginalInits);

/// Helper to keep information about the current `omp begin/end declare
/// variant` nesting.
struct OMPDeclareVariantScope {
  /// The associated OpenMP context selector.
  OMPTraitInfo *TI;

  /// The associated OpenMP context selector mangling.
  std::string NameSuffix;

  OMPDeclareVariantScope(OMPTraitInfo &TI);
};

/// Return the OMPTraitInfo for the surrounding scope, if any.
OMPTraitInfo *getOMPTraitInfoForSurroundingScope() {
  return OMPDeclareVariantScopes.empty() ? nullptr
                                         : OMPDeclareVariantScopes.back().TI;
}

/// The current `omp begin/end declare variant` scopes.
SmallVector<OMPDeclareVariantScope, 4> OMPDeclareVariantScopes;

/// The current `omp begin/end assumes` scopes.
SmallVector<AssumptionAttr *, 4> OMPAssumeScoped;

/// All `omp assumes` we encountered so far.
SmallVector<AssumptionAttr *, 4> OMPAssumeGlobal;

10317public:
/// The declarator \p D defines a function in the scope \p S which is nested
/// in an `omp begin/end declare variant` scope. In this method we create a
/// declaration for \p D and rename \p D according to the OpenMP context
/// selector of the surrounding scope. Return all base functions in \p Bases.
void ActOnStartOfFunctionDefinitionInOpenMPDeclareVariantScope(
    Scope *S, Declarator &D, MultiTemplateParamsArg TemplateParameterLists,
    SmallVectorImpl<FunctionDecl *> &Bases);

/// Register \p D as specialization of all base functions in \p Bases in the
/// current `omp begin/end declare variant` scope.
void ActOnFinishedFunctionDefinitionInOpenMPDeclareVariantScope(
    Decl *D, SmallVectorImpl<FunctionDecl *> &Bases);

/// Act on \p D, a function definition inside of an `omp [begin/end] assumes`.
void ActOnFinishedFunctionDefinitionInOpenMPAssumeScope(Decl *D);

/// Can we exit an OpenMP declare variant scope at the moment.
bool isInOpenMPDeclareVariantScope() const {
  return !OMPDeclareVariantScopes.empty();
}

/// Given the potential call expression \p Call, determine if there is a
/// specialization via the OpenMP declare variant mechanism available. If
/// there is, return the specialized call expression, otherwise return the
/// original \p Call.
ExprResult ActOnOpenMPCall(ExprResult Call, Scope *Scope,
                           SourceLocation LParenLoc, MultiExprArg ArgExprs,
                           SourceLocation RParenLoc, Expr *ExecConfig);

/// Handle a `omp begin declare variant`.
void ActOnOpenMPBeginDeclareVariant(SourceLocation Loc, OMPTraitInfo &TI);

/// Handle a `omp end declare variant`.
void ActOnOpenMPEndDeclareVariant();

/// Checks if the variant/multiversion functions are compatible.
bool areMultiversionVariantFunctionsCompatible(
    const FunctionDecl *OldFD, const FunctionDecl *NewFD,
    const PartialDiagnostic &NoProtoDiagID,
    const PartialDiagnosticAt &NoteCausedDiagIDAt,
    const PartialDiagnosticAt &NoSupportDiagIDAt,
    const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
    bool ConstexprSupported, bool CLinkageMayDiffer);

/// Function tries to capture lambda's captured variables in the OpenMP region
/// before the original lambda is captured.
void tryCaptureOpenMPLambdas(ValueDecl *V);

/// Return true if the provided declaration \a VD should be captured by
/// reference.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
/// \param OpenMPCaptureLevel Capture level within an OpenMP construct.
bool isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level,
                           unsigned OpenMPCaptureLevel) const;

/// Check if the specified variable is used in one of the private
/// clauses (private, firstprivate, lastprivate, reduction etc.) in OpenMP
/// constructs.
VarDecl *isOpenMPCapturedDecl(ValueDecl *D, bool CheckScopeInfo = false,
                              unsigned StopAt = 0);
ExprResult getOpenMPCapturedExpr(VarDecl *Capture, ExprValueKind VK,
                                 ExprObjectKind OK, SourceLocation Loc);

/// If the current region is a loop-based region, mark the start of the loop
/// construct.
void startOpenMPLoop();

/// If the current region is a range loop-based region, mark the start of the
/// loop construct.
void startOpenMPCXXRangeFor();

/// Check if the specified variable is used in 'private' clause.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
OpenMPClauseKind isOpenMPPrivateDecl(ValueDecl *D, unsigned Level,
                                     unsigned CapLevel) const;

/// Sets OpenMP capture kind (OMPC_private, OMPC_firstprivate, OMPC_map etc.)
/// for \p FD based on DSA for the provided corresponding captured declaration
/// \p D.
void setOpenMPCaptureKind(FieldDecl *FD, const ValueDecl *D, unsigned Level);

/// Check if the specified variable is captured  by 'target' directive.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
bool isOpenMPTargetCapturedDecl(const ValueDecl *D, unsigned Level,
                                unsigned CaptureLevel) const;

/// Check if the specified global variable must be captured  by outer capture
/// regions.
/// \param Level Relative level of nested OpenMP construct for that
/// the check is performed.
bool isOpenMPGlobalCapturedDecl(ValueDecl *D, unsigned Level,
                                unsigned CaptureLevel) const;

ExprResult PerformOpenMPImplicitIntegerConversion(SourceLocation OpLoc,
                                                  Expr *Op);
/// Called on start of new data sharing attribute block.
void StartOpenMPDSABlock(OpenMPDirectiveKind K,
                         const DeclarationNameInfo &DirName, Scope *CurScope,
                         SourceLocation Loc);
/// Start analysis of clauses.
void StartOpenMPClause(OpenMPClauseKind K);
/// End analysis of clauses.
void EndOpenMPClause();
/// Called on end of data sharing attribute block.
void EndOpenMPDSABlock(Stmt *CurDirective);

/// Check if the current region is an OpenMP loop region and if it is,
/// mark loop control variable, used in \p Init for loop initialization, as
/// private by default.
/// \param Init First part of the for loop.
void ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init);

// OpenMP directives and clauses.
/// Called on correct id-expression from the '#pragma omp
/// threadprivate'.
ExprResult ActOnOpenMPIdExpression(Scope *CurScope, CXXScopeSpec &ScopeSpec,
                                   const DeclarationNameInfo &Id,
                                   OpenMPDirectiveKind Kind);
/// Called on well-formed '#pragma omp threadprivate'.
DeclGroupPtrTy ActOnOpenMPThreadprivateDirective(
                                   SourceLocation Loc,
                                   ArrayRef<Expr *> VarList);
/// Builds a new OpenMPThreadPrivateDecl and checks its correctness.
OMPThreadPrivateDecl *CheckOMPThreadPrivateDecl(SourceLocation Loc,
                                                ArrayRef<Expr *> VarList);
/// Called on well-formed '#pragma omp allocate'.
DeclGroupPtrTy ActOnOpenMPAllocateDirective(SourceLocation Loc,
                                            ArrayRef<Expr *> VarList,
                                            ArrayRef<OMPClause *> Clauses,
                                            DeclContext *Owner = nullptr);

/// Called on well-formed '#pragma omp [begin] assume[s]'.
void ActOnOpenMPAssumesDirective(SourceLocation Loc,
                                 OpenMPDirectiveKind DKind,
                                 ArrayRef<StringRef> Assumptions,
                                 bool SkippedClauses);

/// Check if there is an active global `omp begin assumes` directive.
bool isInOpenMPAssumeScope() const { return !OMPAssumeScoped.empty(); }

/// Check if there is an active global `omp assumes` directive.
bool hasGlobalOpenMPAssumes() const { return !OMPAssumeGlobal.empty(); }

/// Called on well-formed '#pragma omp end assumes'.
void ActOnOpenMPEndAssumesDirective();

/// Called on well-formed '#pragma omp requires'.
DeclGroupPtrTy ActOnOpenMPRequiresDirective(SourceLocation Loc,
                                            ArrayRef<OMPClause *> ClauseList);
/// Check restrictions on Requires directive
OMPRequiresDecl *CheckOMPRequiresDecl(SourceLocation Loc,
                                      ArrayRef<OMPClause *> Clauses);
/// Check if the specified type is allowed to be used in 'omp declare
/// reduction' construct.
QualType ActOnOpenMPDeclareReductionType(SourceLocation TyLoc,
                                         TypeResult ParsedType);
/// Called on start of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveStart(
    Scope *S, DeclContext *DC, DeclarationName Name,
    ArrayRef<std::pair<QualType, SourceLocation>> ReductionTypes,
    AccessSpecifier AS, Decl *PrevDeclInScope = nullptr);
/// Initialize declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerEnd(Decl *D, Expr *Combiner);
/// Initialize declare reduction construct initializer.
/// \return omp_priv variable.
VarDecl *ActOnOpenMPDeclareReductionInitializerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionInitializerEnd(Decl *D, Expr *Initializer,
                                               VarDecl *OmpPrivParm);
/// Called at the end of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveEnd(
    Scope *S, DeclGroupPtrTy DeclReductions, bool IsValid);

/// Check variable declaration in 'omp declare mapper' construct.
TypeResult ActOnOpenMPDeclareMapperVarDecl(Scope *S, Declarator &D);
/// Check if the specified type is allowed to be used in 'omp declare
/// mapper' construct.
QualType ActOnOpenMPDeclareMapperType(SourceLocation TyLoc,
                                      TypeResult ParsedType);
/// Called on start of '#pragma omp declare mapper'.
DeclGroupPtrTy ActOnOpenMPDeclareMapperDirective(
    Scope *S, DeclContext *DC, DeclarationName Name, QualType MapperType,
    SourceLocation StartLoc, DeclarationName VN, AccessSpecifier AS,
    Expr *MapperVarRef, ArrayRef<OMPClause *> Clauses,
    Decl *PrevDeclInScope = nullptr);
/// Build the mapper variable of '#pragma omp declare mapper'.
ExprResult ActOnOpenMPDeclareMapperDirectiveVarDecl(Scope *S,
                                                    QualType MapperType,
                                                    SourceLocation StartLoc,
                                                    DeclarationName VN);
bool isOpenMPDeclareMapperVarDeclAllowed(const VarDecl *VD) const;
const ValueDecl *getOpenMPDeclareMapperVarName() const;

/// Called on the start of target region i.e. '#pragma omp declare target'.
bool ActOnStartOpenMPDeclareTargetContext(DeclareTargetContextInfo &DTCI);

/// Called at the end of target region i.e. '#pragma omp end declare target'.
const DeclareTargetContextInfo ActOnOpenMPEndDeclareTargetDirective();

/// Called once a target context is completed, that can be when a
/// '#pragma omp end declare target' was encountered or when a
/// '#pragma omp declare target' without declaration-definition-seq was
/// encountered.
void ActOnFinishedOpenMPDeclareTargetContext(DeclareTargetContextInfo &DTCI);

/// Searches for the provided declaration name for OpenMP declare target
/// directive.
NamedDecl *lookupOpenMPDeclareTargetName(Scope *CurScope,
                                         CXXScopeSpec &ScopeSpec,
                                         const DeclarationNameInfo &Id);

/// Called on correct id-expression from the '#pragma omp declare target'.
void ActOnOpenMPDeclareTargetName(NamedDecl *ND, SourceLocation Loc,
                                  OMPDeclareTargetDeclAttr::MapTypeTy MT,
                                  OMPDeclareTargetDeclAttr::DevTypeTy DT);

/// Check declaration inside target region.
void
checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D,
                                 SourceLocation IdLoc = SourceLocation());
/// Finishes analysis of the deferred functions calls that may be declared as
/// host/nohost during device/host compilation.
void finalizeOpenMPDelayedAnalysis(const FunctionDecl *Caller,
                                   const FunctionDecl *Callee,
                                   SourceLocation Loc);
/// Return true inside OpenMP declare target region.
bool isInOpenMPDeclareTargetContext() const {
  return !DeclareTargetNesting.empty();
}
/// Return true inside OpenMP target region.
bool isInOpenMPTargetExecutionDirective() const;

/// Return the number of captured regions created for an OpenMP directive.
static int getOpenMPCaptureLevels(OpenMPDirectiveKind Kind);

/// Initialization of captured region for OpenMP region.
void ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope);

/// Called for syntactical loops (ForStmt or CXXForRangeStmt) associated to
/// an OpenMP loop directive.
StmtResult ActOnOpenMPCanonicalLoop(Stmt *AStmt);

/// End of OpenMP region.
///
/// \param S Statement associated with the current OpenMP region.
/// \param Clauses List of clauses for the current OpenMP region.
///
/// \returns Statement for finished OpenMP region.
StmtResult ActOnOpenMPRegionEnd(StmtResult S, ArrayRef<OMPClause *> Clauses);
StmtResult ActOnOpenMPExecutableDirective(
    OpenMPDirectiveKind Kind, const DeclarationNameInfo &DirName,
    OpenMPDirectiveKind CancelRegion, ArrayRef<OMPClause *> Clauses,
    Stmt *AStmt, SourceLocation StartLoc, SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt,
                                        SourceLocation StartLoc,
                                        SourceLocation EndLoc);
using VarsWithInheritedDSAType =
    llvm::SmallDenseMap<const ValueDecl *, const Expr *, 4>;
/// Called on well-formed '\#pragma omp simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                         SourceLocation StartLoc, SourceLocation EndLoc,
                         VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '#pragma omp tile' after parsing of its clauses and
/// the associated statement.
StmtResult ActOnOpenMPTileDirective(ArrayRef<OMPClause *> Clauses,
                                    Stmt *AStmt, SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '#pragma omp unroll' after parsing of its clauses
/// and the associated statement.
StmtResult ActOnOpenMPUnrollDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp for' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                        SourceLocation StartLoc, SourceLocation EndLoc,
                        VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp for simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                            SourceLocation StartLoc, SourceLocation EndLoc,
                            VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp sections' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp section' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSectionDirective(Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp single' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSingleDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp master' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterDirective(Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp critical' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPCriticalDirective(const DeclarationNameInfo &DirName,
                                        ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel for' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel for simd' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelMasterDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel sections' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                                Stmt *AStmt,
                                                SourceLocation StartLoc,
                                                SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp task' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTaskDirective(ArrayRef<OMPClause *> Clauses,
                                    Stmt *AStmt, SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskyield'.
StmtResult ActOnOpenMPTaskyieldDirective(SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp barrier'.
StmtResult ActOnOpenMPBarrierDirective(SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskwait'.
StmtResult ActOnOpenMPTaskwaitDirective(SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskgroup'.
StmtResult ActOnOpenMPTaskgroupDirective(ArrayRef<OMPClause *> Clauses,
                                         Stmt *AStmt, SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp flush'.
StmtResult ActOnOpenMPFlushDirective(ArrayRef<OMPClause *> Clauses,
                                     SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp depobj'.
StmtResult ActOnOpenMPDepobjDirective(ArrayRef<OMPClause *> Clauses,
                                      SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp scan'.
StmtResult ActOnOpenMPScanDirective(ArrayRef<OMPClause *> Clauses,
                                    SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp ordered' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
                                       Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp atomic' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target data' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTargetDataDirective(ArrayRef<OMPClause *> Clauses,
                                          Stmt *AStmt, SourceLocation StartLoc,
                                          SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target enter data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetEnterDataDirective(ArrayRef<OMPClause *> Clauses,
                                               SourceLocation StartLoc,
                                               SourceLocation EndLoc,
                                               Stmt *AStmt);
/// Called on well-formed '\#pragma omp target exit data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetExitDataDirective(ArrayRef<OMPClause *> Clauses,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc,
                                              Stmt *AStmt);
/// Called on well-formed '\#pragma omp target parallel' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target parallel for' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPTargetParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                     Stmt *AStmt, SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp cancellation point'.
StmtResult
ActOnOpenMPCancellationPointDirective(SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp cancel'.
StmtResult ActOnOpenMPCancelDirective(ArrayRef<OMPClause *> Clauses,
                                      SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp taskloop' after parsing of the
/// associated statement.
StmtResult
ActOnOpenMPTaskLoopDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                             SourceLocation StartLoc, SourceLocation EndLoc,
                             VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp taskloop simd' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp master taskloop' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp master taskloop simd' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPMasterTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master taskloop' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPParallelMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master taskloop simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPParallelMasterTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPDistributeDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target update'.
StmtResult ActOnOpenMPTargetUpdateDirective(ArrayRef<OMPClause *> Clauses,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc,
                                            Stmt *AStmt);
/// Called on well-formed '\#pragma omp distribute parallel for' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target parallel for simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target simd' after parsing of
/// the associated statement.
StmtResult
ActOnOpenMPTargetSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute simd' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                           Stmt *AStmt,
                                           SourceLocation StartLoc,
                                           SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target teams distribute' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for
/// simd' after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp interop'.
StmtResult ActOnOpenMPInteropDirective(ArrayRef<OMPClause *> Clauses,
                                       SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp dispatch' after parsing of the
// /associated statement.
StmtResult ActOnOpenMPDispatchDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp masked' after parsing of the
// /associated statement.
StmtResult ActOnOpenMPMaskedDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);

/// Checks correctness of linear modifiers.
bool CheckOpenMPLinearModifier(OpenMPLinearClauseKind LinKind,
                               SourceLocation LinLoc);
/// Checks that the specified declaration matches requirements for the linear
/// decls.
bool CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
                           OpenMPLinearClauseKind LinKind, QualType Type,
                           bool IsDeclareSimd = false);

/// Called on well-formed '\#pragma omp declare simd' after parsing of
/// the associated method/function.
DeclGroupPtrTy ActOnOpenMPDeclareSimdDirective(
    DeclGroupPtrTy DG, OMPDeclareSimdDeclAttr::BranchStateTy BS,
    Expr *Simdlen, ArrayRef<Expr *> Uniforms, ArrayRef<Expr *> Aligneds,
    ArrayRef<Expr *> Alignments, ArrayRef<Expr *> Linears,
    ArrayRef<unsigned> LinModifiers, ArrayRef<Expr *> Steps, SourceRange SR);

/// Checks '\#pragma omp declare variant' variant function and original
/// functions after parsing of the associated method/function.
/// \param DG Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \param TI The trait info object representing the match clause.
/// \returns None, if the function/variant function are not compatible with
/// the pragma, pair of original function/variant ref expression otherwise.
Optional<std::pair<FunctionDecl *, Expr *>>
checkOpenMPDeclareVariantFunction(DeclGroupPtrTy DG, Expr *VariantRef,
                                  OMPTraitInfo &TI, SourceRange SR);

/// Called on well-formed '\#pragma omp declare variant' after parsing of
/// the associated method/function.
/// \param FD Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \param TI The context traits associated with the function variant.
void ActOnOpenMPDeclareVariantDirective(FunctionDecl *FD, Expr *VariantRef,
                                        OMPTraitInfo &TI, SourceRange SR);

OMPClause *ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind,
                                       Expr *Expr,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'allocator' clause.
OMPClause *ActOnOpenMPAllocatorClause(Expr *Allocator,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'if' clause.
OMPClause *ActOnOpenMPIfClause(OpenMPDirectiveKind NameModifier,
                               Expr *Condition, SourceLocation StartLoc,
                               SourceLocation LParenLoc,
                               SourceLocation NameModifierLoc,
                               SourceLocation ColonLoc,
                               SourceLocation EndLoc);
/// Called on well-formed 'final' clause.
OMPClause *ActOnOpenMPFinalClause(Expr *Condition, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'num_threads' clause.
OMPClause *ActOnOpenMPNumThreadsClause(Expr *NumThreads,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'safelen' clause.
OMPClause *ActOnOpenMPSafelenClause(Expr *Length,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simdlen' clause.
OMPClause *ActOnOpenMPSimdlenClause(Expr *Length, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-form 'sizes' clause.
OMPClause *ActOnOpenMPSizesClause(ArrayRef<Expr *> SizeExprs,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-form 'full' clauses.
OMPClause *ActOnOpenMPFullClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-form 'partial' clauses.
OMPClause *ActOnOpenMPPartialClause(Expr *FactorExpr, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'collapse' clause.
OMPClause *ActOnOpenMPCollapseClause(Expr *NumForLoops,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'ordered' clause.
OMPClause *
ActOnOpenMPOrderedClause(SourceLocation StartLoc, SourceLocation EndLoc,
                         SourceLocation LParenLoc = SourceLocation(),
                         Expr *NumForLoops = nullptr);
/// Called on well-formed 'grainsize' clause.
OMPClause *ActOnOpenMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'num_tasks' clause.
OMPClause *ActOnOpenMPNumTasksClause(Expr *NumTasks, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'hint' clause.
OMPClause *ActOnOpenMPHintClause(Expr *Hint, SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'detach' clause.
OMPClause *ActOnOpenMPDetachClause(Expr *Evt, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);

OMPClause *ActOnOpenMPSimpleClause(OpenMPClauseKind Kind,
                                   unsigned Argument,
                                   SourceLocation ArgumentLoc,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'default' clause.
OMPClause *ActOnOpenMPDefaultClause(llvm::omp::DefaultKind Kind,
                                    SourceLocation KindLoc,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'proc_bind' clause.
OMPClause *ActOnOpenMPProcBindClause(llvm::omp::ProcBindKind Kind,
                                     SourceLocation KindLoc,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'order' clause.
OMPClause *ActOnOpenMPOrderClause(OpenMPOrderClauseKind Kind,
                                  SourceLocation KindLoc,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'update' clause.
OMPClause *ActOnOpenMPUpdateClause(OpenMPDependClauseKind Kind,
                                   SourceLocation KindLoc,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);

OMPClause *ActOnOpenMPSingleExprWithArgClause(
    OpenMPClauseKind Kind, ArrayRef<unsigned> Arguments, Expr *Expr,
    SourceLocation StartLoc, SourceLocation LParenLoc,
    ArrayRef<SourceLocation> ArgumentsLoc, SourceLocation DelimLoc,
    SourceLocation EndLoc);
/// Called on well-formed 'schedule' clause.
OMPClause *ActOnOpenMPScheduleClause(
    OpenMPScheduleClauseModifier M1, OpenMPScheduleClauseModifier M2,
    OpenMPScheduleClauseKind Kind, Expr *ChunkSize, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation M1Loc, SourceLocation M2Loc,
    SourceLocation KindLoc, SourceLocation CommaLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPClause(OpenMPClauseKind Kind, SourceLocation StartLoc,
                             SourceLocation EndLoc);
/// Called on well-formed 'nowait' clause.
OMPClause *ActOnOpenMPNowaitClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'untied' clause.
OMPClause *ActOnOpenMPUntiedClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'mergeable' clause.
OMPClause *ActOnOpenMPMergeableClause(SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'read' clause.
OMPClause *ActOnOpenMPReadClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'write' clause.
OMPClause *ActOnOpenMPWriteClause(SourceLocation StartLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'update' clause.
OMPClause *ActOnOpenMPUpdateClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'capture' clause.
OMPClause *ActOnOpenMPCaptureClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'seq_cst' clause.
OMPClause *ActOnOpenMPSeqCstClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'acq_rel' clause.
OMPClause *ActOnOpenMPAcqRelClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'acquire' clause.
OMPClause *ActOnOpenMPAcquireClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'release' clause.
OMPClause *ActOnOpenMPReleaseClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'relaxed' clause.
OMPClause *ActOnOpenMPRelaxedClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);

/// Called on well-formed 'init' clause.
OMPClause *ActOnOpenMPInitClause(Expr *InteropVar, ArrayRef<Expr *> PrefExprs,
                                 bool IsTarget, bool IsTargetSync,
                                 SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation VarLoc,
                                 SourceLocation EndLoc);

/// Called on well-formed 'use' clause.
OMPClause *ActOnOpenMPUseClause(Expr *InteropVar, SourceLocation StartLoc,
                                SourceLocation LParenLoc,
                                SourceLocation VarLoc, SourceLocation EndLoc);

/// Called on well-formed 'destroy' clause.
OMPClause *ActOnOpenMPDestroyClause(Expr *InteropVar, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation VarLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'novariants' clause.
OMPClause *ActOnOpenMPNovariantsClause(Expr *Condition,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'nocontext' clause.
OMPClause *ActOnOpenMPNocontextClause(Expr *Condition,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'filter' clause.
OMPClause *ActOnOpenMPFilterClause(Expr *ThreadID, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'threads' clause.
OMPClause *ActOnOpenMPThreadsClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simd' clause.
OMPClause *ActOnOpenMPSIMDClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'nogroup' clause.
OMPClause *ActOnOpenMPNogroupClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
                                                SourceLocation EndLoc);

/// Called on well-formed 'reverse_offload' clause.
OMPClause *ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'dynamic_allocators' clause.
OMPClause *ActOnOpenMPDynamicAllocatorsClause(SourceLocation StartLoc,
                                              SourceLocation EndLoc);

/// Called on well-formed 'atomic_default_mem_order' clause.
OMPClause *ActOnOpenMPAtomicDefaultMemOrderClause(
    OpenMPAtomicDefaultMemOrderClauseKind Kind, SourceLocation KindLoc,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPVarListClause(
    OpenMPClauseKind Kind, ArrayRef<Expr *> Vars, Expr *DepModOrTailExpr,
    const OMPVarListLocTy &Locs, SourceLocation ColonLoc,
    CXXScopeSpec &ReductionOrMapperIdScopeSpec,
    DeclarationNameInfo &ReductionOrMapperId, int ExtraModifier,
    ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
    ArrayRef<SourceLocation> MapTypeModifiersLoc, bool IsMapTypeImplicit,
    SourceLocation ExtraModifierLoc,
    ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
    ArrayRef<SourceLocation> MotionModifiersLoc);
/// Called on well-formed 'inclusive' clause.
OMPClause *ActOnOpenMPInclusiveClause(ArrayRef<Expr *> VarList,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'exclusive' clause.
OMPClause *ActOnOpenMPExclusiveClause(ArrayRef<Expr *> VarList,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'allocate' clause.
OMPClause *
ActOnOpenMPAllocateClause(Expr *Allocator, ArrayRef<Expr *> VarList,
                          SourceLocation StartLoc, SourceLocation ColonLoc,
                          SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'private' clause.
OMPClause *ActOnOpenMPPrivateClause(ArrayRef<Expr *> VarList,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'firstprivate' clause.
OMPClause *ActOnOpenMPFirstprivateClause(ArrayRef<Expr *> VarList,
                                         SourceLocation StartLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed 'lastprivate' clause.
OMPClause *ActOnOpenMPLastprivateClause(
    ArrayRef<Expr *> VarList, OpenMPLastprivateModifier LPKind,
    SourceLocation LPKindLoc, SourceLocation ColonLoc,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'shared' clause.
OMPClause *ActOnOpenMPSharedClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'reduction' clause.
OMPClause *ActOnOpenMPReductionClause(
    ArrayRef<Expr *> VarList, OpenMPReductionClauseModifier Modifier,
    SourceLocation StartLoc, SourceLocation LParenLoc,
    SourceLocation ModifierLoc, SourceLocation ColonLoc,
    SourceLocation EndLoc, CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'task_reduction' clause.
OMPClause *ActOnOpenMPTaskReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'in_reduction' clause.
OMPClause *ActOnOpenMPInReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'linear' clause.
OMPClause *
ActOnOpenMPLinearClause(ArrayRef<Expr *> VarList, Expr *Step,
                        SourceLocation StartLoc, SourceLocation LParenLoc,
                        OpenMPLinearClauseKind LinKind, SourceLocation LinLoc,
                        SourceLocation ColonLoc, SourceLocation EndLoc);
/// Called on well-formed 'aligned' clause.
OMPClause *ActOnOpenMPAlignedClause(ArrayRef<Expr *> VarList,
                                    Expr *Alignment,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation ColonLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'copyin' clause.
OMPClause *ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'copyprivate' clause.
OMPClause *ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'flush' pseudo clause.
OMPClause *ActOnOpenMPFlushClause(ArrayRef<Expr *> VarList,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'depobj' pseudo clause.
OMPClause *ActOnOpenMPDepobjClause(Expr *Depobj, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'depend' clause.
OMPClause *
ActOnOpenMPDependClause(Expr *DepModifier, OpenMPDependClauseKind DepKind,
                        SourceLocation DepLoc, SourceLocation ColonLoc,
                        ArrayRef<Expr *> VarList, SourceLocation StartLoc,
                        SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'device' clause.
OMPClause *ActOnOpenMPDeviceClause(OpenMPDeviceClauseModifier Modifier,
                                   Expr *Device, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation ModifierLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'map' clause.
OMPClause *
ActOnOpenMPMapClause(ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
                     ArrayRef<SourceLocation> MapTypeModifiersLoc,
                     CXXScopeSpec &MapperIdScopeSpec,
                     DeclarationNameInfo &MapperId,
                     OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
                     SourceLocation MapLoc, SourceLocation ColonLoc,
                     ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                     ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'num_teams' clause.
OMPClause *ActOnOpenMPNumTeamsClause(Expr *NumTeams, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'thread_limit' clause.
OMPClause *ActOnOpenMPThreadLimitClause(Expr *ThreadLimit,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'priority' clause.
OMPClause *ActOnOpenMPPriorityClause(Expr *Priority, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'dist_schedule' clause.
OMPClause *ActOnOpenMPDistScheduleClause(
    OpenMPDistScheduleClauseKind Kind, Expr *ChunkSize,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation KindLoc,
    SourceLocation CommaLoc, SourceLocation EndLoc);
/// Called on well-formed 'defaultmap' clause.
OMPClause *ActOnOpenMPDefaultmapClause(
    OpenMPDefaultmapClauseModifier M, OpenMPDefaultmapClauseKind Kind,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation MLoc,
    SourceLocation KindLoc, SourceLocation EndLoc);
/// Called on well-formed 'to' clause.
OMPClause *
ActOnOpenMPToClause(ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
                    ArrayRef<SourceLocation> MotionModifiersLoc,
                    CXXScopeSpec &MapperIdScopeSpec,
                    DeclarationNameInfo &MapperId, SourceLocation ColonLoc,
                    ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                    ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'from' clause.
OMPClause *
ActOnOpenMPFromClause(ArrayRef<OpenMPMotionModifierKind> MotionModifiers,
                      ArrayRef<SourceLocation> MotionModifiersLoc,
                      CXXScopeSpec &MapperIdScopeSpec,
                      DeclarationNameInfo &MapperId, SourceLocation ColonLoc,
                      ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                      ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'use_device_ptr' clause.
OMPClause *ActOnOpenMPUseDevicePtrClause(ArrayRef<Expr *> VarList,
                                         const OMPVarListLocTy &Locs);
/// Called on well-formed 'use_device_addr' clause.
OMPClause *ActOnOpenMPUseDeviceAddrClause(ArrayRef<Expr *> VarList,
                                          const OMPVarListLocTy &Locs);
/// Called on well-formed 'is_device_ptr' clause.
OMPClause *ActOnOpenMPIsDevicePtrClause(ArrayRef<Expr *> VarList,
                                        const OMPVarListLocTy &Locs);
/// Called on well-formed 'nontemporal' clause.
OMPClause *ActOnOpenMPNontemporalClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);

/// Data for list of allocators.
struct UsesAllocatorsData {
  /// Allocator.
  Expr *Allocator = nullptr;
  /// Allocator traits.
  Expr *AllocatorTraits = nullptr;
  /// Locations of '(' and ')' symbols.
  SourceLocation LParenLoc, RParenLoc;
};
/// Called on well-formed 'uses_allocators' clause.
OMPClause *ActOnOpenMPUsesAllocatorClause(SourceLocation StartLoc,
                                          SourceLocation LParenLoc,
                                          SourceLocation EndLoc,
                                          ArrayRef<UsesAllocatorsData> Data);
/// Called on well-formed 'affinity' clause.
OMPClause *ActOnOpenMPAffinityClause(SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation ColonLoc,
                                     SourceLocation EndLoc, Expr *Modifier,
                                     ArrayRef<Expr *> Locators);

/// The kind of conversion being performed.
enum CheckedConversionKind {
  /// An implicit conversion.
  CCK_ImplicitConversion,
  /// A C-style cast.
  CCK_CStyleCast,
  /// A functional-style cast.
  CCK_FunctionalCast,
  /// A cast other than a C-style cast.
  CCK_OtherCast,
  /// A conversion for an operand of a builtin overloaded operator.
  CCK_ForBuiltinOverloadedOp
};

static bool isCast(CheckedConversionKind CCK) {
  return CCK == CCK_CStyleCast || CCK == CCK_FunctionalCast ||
         CCK == CCK_OtherCast;
}

/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
/// cast.  If there is already an implicit cast, merge into the existing one.
/// If isLvalue, the result of the cast is an lvalue.
ExprResult
ImpCastExprToType(Expr *E, QualType Type, CastKind CK,
                  ExprValueKind VK = VK_PRValue,
                  const CXXCastPath *BasePath = nullptr,
                  CheckedConversionKind CCK = CCK_ImplicitConversion);

/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
/// to the conversion from scalar type ScalarTy to the Boolean type.
static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);

/// IgnoredValueConversions - Given that an expression's result is
/// syntactically ignored, perform any conversions that are
/// required.
ExprResult IgnoredValueConversions(Expr *E);

// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2) and converts
// functions and arrays to their respective pointers (C99 6.3.2.1).
ExprResult UsualUnaryConversions(Expr *E);

/// CallExprUnaryConversions - a special case of an unary conversion
/// performed on a function designator of a call expression.
ExprResult CallExprUnaryConversions(Expr *E);

// DefaultFunctionArrayConversion - converts functions and arrays
// to their respective pointers (C99 6.3.2.1).
ExprResult DefaultFunctionArrayConversion(Expr *E, bool Diagnose = true);

// DefaultFunctionArrayLvalueConversion - converts functions and
// arrays to their respective pointers and performs the
// lvalue-to-rvalue conversion.
ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
                                                bool Diagnose = true);

// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
// the operand. This function is a no-op if the operand has a function type
// or an array type.
ExprResult DefaultLvalueConversion(Expr *E);

// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
// do not have a prototype. Integer promotions are performed on each
// argument, and arguments that have type float are promoted to double.
ExprResult DefaultArgumentPromotion(Expr *E);

/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
/// it as an xvalue. In C++98, the result will still be a prvalue, because
/// we don't have xvalues there.
ExprResult TemporaryMaterializationConversion(Expr *E);

// Used for emitting the right warning by DefaultVariadicArgumentPromotion
enum VariadicCallType {
  VariadicFunction,
  VariadicBlock,
  VariadicMethod,
  VariadicConstructor,
  VariadicDoesNotApply
};

VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
                                     const FunctionProtoType *Proto,
                                     Expr *Fn);

// Used for determining in which context a type is allowed to be passed to a
// vararg function.
enum VarArgKind {
  VAK_Valid,
  VAK_ValidInCXX11,
  VAK_Undefined,
  VAK_MSVCUndefined,
  VAK_Invalid
};

// Determines which VarArgKind fits an expression.
VarArgKind isValidVarArgType(const QualType &Ty);

/// Check to see if the given expression is a valid argument to a variadic
/// function, issuing a diagnostic if not.
void checkVariadicArgument(const Expr *E, VariadicCallType CT);

/// Check whether the given statement can have musttail applied to it,
/// issuing a diagnostic and returning false if not. In the success case,
/// the statement is rewritten to remove implicit nodes from the return
/// value.
bool checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA);

11435private:
/// Check whether the given statement can have musttail applied to it,
/// issuing a diagnostic and returning false if not.
bool checkMustTailAttr(const Stmt *St, const Attr &MTA);

11440public:
/// Check to see if a given expression could have '.c_str()' called on it.
bool hasCStrMethod(const Expr *E);

/// GatherArgumentsForCall - Collector argument expressions for various
/// form of call prototypes.
bool GatherArgumentsForCall(SourceLocation CallLoc, FunctionDecl *FDecl,
                            const FunctionProtoType *Proto,
                            unsigned FirstParam, ArrayRef<Expr *> Args,
                            SmallVectorImpl<Expr *> &AllArgs,
                            VariadicCallType CallType = VariadicDoesNotApply,
                            bool AllowExplicit = false,
                            bool IsListInitialization = false);

// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
// will create a runtime trap if the resulting type is not a POD type.
ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
                                            FunctionDecl *FDecl);

/// Context in which we're performing a usual arithmetic conversion.
enum ArithConvKind {
  /// An arithmetic operation.
  ACK_Arithmetic,
  /// A bitwise operation.
  ACK_BitwiseOp,
  /// A comparison.
  ACK_Comparison,
  /// A conditional (?:) operator.
  ACK_Conditional,
  /// A compound assignment expression.
  ACK_CompAssign,
};

// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
// operands and then handles various conversions that are common to binary
// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
// routine returns the first non-arithmetic type found. The client is
// responsible for emitting appropriate error diagnostics.
QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc, ArithConvKind ACK);

/// AssignConvertType - All of the 'assignment' semantic checks return this
/// enum to indicate whether the assignment was allowed.  These checks are
/// done for simple assignments, as well as initialization, return from
/// function, argument passing, etc.  The query is phrased in terms of a
/// source and destination type.
enum AssignConvertType {
  /// Compatible - the types are compatible according to the standard.
  Compatible,

  /// PointerToInt - The assignment converts a pointer to an int, which we
  /// accept as an extension.
  PointerToInt,

  /// IntToPointer - The assignment converts an int to a pointer, which we
  /// accept as an extension.
  IntToPointer,

  /// FunctionVoidPointer - The assignment is between a function pointer and
  /// void*, which the standard doesn't allow, but we accept as an extension.
  FunctionVoidPointer,

  /// IncompatiblePointer - The assignment is between two pointers types that
  /// are not compatible, but we accept them as an extension.
  IncompatiblePointer,

  /// IncompatibleFunctionPointer - The assignment is between two function
  /// pointers types that are not compatible, but we accept them as an
  /// extension.
  IncompatibleFunctionPointer,

  /// IncompatiblePointerSign - The assignment is between two pointers types
  /// which point to integers which have a different sign, but are otherwise
  /// identical. This is a subset of the above, but broken out because it's by
  /// far the most common case of incompatible pointers.
  IncompatiblePointerSign,

  /// CompatiblePointerDiscardsQualifiers - The assignment discards
  /// c/v/r qualifiers, which we accept as an extension.
  CompatiblePointerDiscardsQualifiers,

  /// IncompatiblePointerDiscardsQualifiers - The assignment
  /// discards qualifiers that we don't permit to be discarded,
  /// like address spaces.
  IncompatiblePointerDiscardsQualifiers,

  /// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
  /// changes address spaces in nested pointer types which is not allowed.
  /// For instance, converting __private int ** to __generic int ** is
  /// illegal even though __private could be converted to __generic.
  IncompatibleNestedPointerAddressSpaceMismatch,

  /// IncompatibleNestedPointerQualifiers - The assignment is between two
  /// nested pointer types, and the qualifiers other than the first two
  /// levels differ e.g. char ** -> const char **, but we accept them as an
  /// extension.
  IncompatibleNestedPointerQualifiers,

  /// IncompatibleVectors - The assignment is between two vector types that
  /// have the same size, which we accept as an extension.
  IncompatibleVectors,

  /// IntToBlockPointer - The assignment converts an int to a block
  /// pointer. We disallow this.
  IntToBlockPointer,

  /// IncompatibleBlockPointer - The assignment is between two block
  /// pointers types that are not compatible.
  IncompatibleBlockPointer,

  /// IncompatibleObjCQualifiedId - The assignment is between a qualified
  /// id type and something else (that is incompatible with it). For example,
  /// "id <XXX>" = "Foo *", where "Foo *" doesn't implement the XXX protocol.
  IncompatibleObjCQualifiedId,

  /// IncompatibleObjCWeakRef - Assigning a weak-unavailable object to an
  /// object with __weak qualifier.
  IncompatibleObjCWeakRef,

  /// Incompatible - We reject this conversion outright, it is invalid to
  /// represent it in the AST.
  Incompatible
};

/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
/// assignment conversion type specified by ConvTy.  This returns true if the
/// conversion was invalid or false if the conversion was accepted.
bool DiagnoseAssignmentResult(AssignConvertType ConvTy,
                              SourceLocation Loc,
                              QualType DstType, QualType SrcType,
                              Expr *SrcExpr, AssignmentAction Action,
                              bool *Complained = nullptr);

/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
/// enum. If AllowMask is true, then we also allow the complement of a valid
/// value, to be used as a mask.
bool IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
                       bool AllowMask) const;

/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
/// integer not in the range of enum values.
void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
                            Expr *SrcExpr);

/// CheckAssignmentConstraints - Perform type checking for assignment,
/// argument passing, variable initialization, and function return values.
/// C99 6.5.16.
AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
                                             QualType LHSType,
                                             QualType RHSType);

/// Check assignment constraints and optionally prepare for a conversion of
/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
/// is true.
AssignConvertType CheckAssignmentConstraints(QualType LHSType,
                                             ExprResult &RHS,
                                             CastKind &Kind,
                                             bool ConvertRHS = true);

/// Check assignment constraints for an assignment of RHS to LHSType.
///
/// \param LHSType The destination type for the assignment.
/// \param RHS The source expression for the assignment.
/// \param Diagnose If \c true, diagnostics may be produced when checking
///        for assignability. If a diagnostic is produced, \p RHS will be
///        set to ExprError(). Note that this function may still return
///        without producing a diagnostic, even for an invalid assignment.
/// \param DiagnoseCFAudited If \c true, the target is a function parameter
///        in an audited Core Foundation API and does not need to be checked
///        for ARC retain issues.
/// \param ConvertRHS If \c true, \p RHS will be updated to model the
///        conversions necessary to perform the assignment. If \c false,
///        \p Diagnose must also be \c false.
AssignConvertType CheckSingleAssignmentConstraints(
    QualType LHSType, ExprResult &RHS, bool Diagnose = true,
    bool DiagnoseCFAudited = false, bool ConvertRHS = true);

// If the lhs type is a transparent union, check whether we
// can initialize the transparent union with the given expression.
AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
                                                           ExprResult &RHS);

bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);

bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);

ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     AssignmentAction Action,
                                     bool AllowExplicit = false);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const ImplicitConversionSequence& ICS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK
                                        = CCK_ImplicitConversion);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const StandardConversionSequence& SCS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK);

ExprResult PerformQualificationConversion(
    Expr *E, QualType Ty, ExprValueKind VK = VK_PRValue,
    CheckedConversionKind CCK = CCK_ImplicitConversion);

/// the following "Check" methods will return a valid/converted QualType
/// or a null QualType (indicating an error diagnostic was issued).

/// type checking binary operators (subroutines of CreateBuiltinBinOp).
QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
                         ExprResult &RHS);
QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
                               ExprResult &RHS);
QualType CheckPointerToMemberOperands( // C++ 5.5
  ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
  SourceLocation OpLoc, bool isIndirect);
QualType CheckMultiplyDivideOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, bool IsCompAssign,
  bool IsDivide);
QualType CheckRemainderOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  bool IsCompAssign = false);
QualType CheckAdditionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, QualType* CompLHSTy = nullptr);
QualType CheckSubtractionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  QualType* CompLHSTy = nullptr);
QualType CheckShiftOperands( // C99 6.5.7
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, bool IsCompAssign = false);
void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
QualType CheckCompareOperands( // C99 6.5.8/9
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckBitwiseOperands( // C99 6.5.[10...12]
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckLogicalOperands( // C99 6.5.[13,14]
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc);
// CheckAssignmentOperands is used for both simple and compound assignment.
// For simple assignment, pass both expressions and a null converted type.
// For compound assignment, pass both expressions and the converted type.
QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
  Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType);

ExprResult checkPseudoObjectIncDec(Scope *S, SourceLocation OpLoc,
                                   UnaryOperatorKind Opcode, Expr *Op);
ExprResult checkPseudoObjectAssignment(Scope *S, SourceLocation OpLoc,
                                       BinaryOperatorKind Opcode,
                                       Expr *LHS, Expr *RHS);
ExprResult checkPseudoObjectRValue(Expr *E);
Expr *recreateSyntacticForm(PseudoObjectExpr *E);

QualType CheckConditionalOperands( // C99 6.5.15
  ExprResult &Cond, ExprResult &LHS, ExprResult &RHS,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation QuestionLoc);
QualType CXXCheckConditionalOperands( // C++ 5.16
  ExprResult &cond, ExprResult &lhs, ExprResult &rhs,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation questionLoc);
QualType CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
                                     ExprResult &RHS,
                                     SourceLocation QuestionLoc);
QualType FindCompositePointerType(SourceLocation Loc, Expr *&E1, Expr *&E2,
                                  bool ConvertArgs = true);
QualType FindCompositePointerType(SourceLocation Loc,
                                  ExprResult &E1, ExprResult &E2,
                                  bool ConvertArgs = true) {
  Expr *E1Tmp = E1.get(), *E2Tmp = E2.get();
  QualType Composite =
      FindCompositePointerType(Loc, E1Tmp, E2Tmp, ConvertArgs);
  E1 = E1Tmp;
  E2 = E2Tmp;
  return Composite;
}

QualType FindCompositeObjCPointerType(ExprResult &LHS, ExprResult &RHS,
                                      SourceLocation QuestionLoc);

bool DiagnoseConditionalForNull(Expr *LHSExpr, Expr *RHSExpr,
                                SourceLocation QuestionLoc);

void DiagnoseAlwaysNonNullPointer(Expr *E,
                                  Expr::NullPointerConstantKind NullType,
                                  bool IsEqual, SourceRange Range);

/// type checking for vector binary operators.
QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
                             SourceLocation Loc, bool IsCompAssign,
                             bool AllowBothBool, bool AllowBoolConversion);
QualType GetSignedVectorType(QualType V);
QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc,
                                    BinaryOperatorKind Opc);
QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc);

/// Type checking for matrix binary operators.
QualType CheckMatrixElementwiseOperands(ExprResult &LHS, ExprResult &RHS,
                                        SourceLocation Loc,
                                        bool IsCompAssign);
QualType CheckMatrixMultiplyOperands(ExprResult &LHS, ExprResult &RHS,
                                     SourceLocation Loc, bool IsCompAssign);

bool isValidSveBitcast(QualType srcType, QualType destType);

bool areMatrixTypesOfTheSameDimension(QualType srcTy, QualType destTy);

bool areVectorTypesSameSize(QualType srcType, QualType destType);
bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
bool isLaxVectorConversion(QualType srcType, QualType destType);

/// type checking declaration initializers (C99 6.7.8)
bool CheckForConstantInitializer(Expr *e, QualType t);

// type checking C++ declaration initializers (C++ [dcl.init]).

/// ReferenceCompareResult - Expresses the result of comparing two
/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
enum ReferenceCompareResult {
  /// Ref_Incompatible - The two types are incompatible, so direct
  /// reference binding is not possible.
  Ref_Incompatible = 0,
  /// Ref_Related - The two types are reference-related, which means
  /// that their unqualified forms (T1 and T2) are either the same
  /// or T1 is a base class of T2.
  Ref_Related,
  /// Ref_Compatible - The two types are reference-compatible.
  Ref_Compatible
};

// Fake up a scoped enumeration that still contextually converts to bool.
struct ReferenceConversionsScope {
  /// The conversions that would be performed on an lvalue of type T2 when
  /// binding a reference of type T1 to it, as determined when evaluating
  /// whether T1 is reference-compatible with T2.
  enum ReferenceConversions {
    Qualification = 0x1,
    NestedQualification = 0x2,
    Function = 0x4,
    DerivedToBase = 0x8,
    ObjC = 0x10,
    ObjCLifetime = 0x20,

    LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/ObjCLifetime)LLVM_BITMASK_LARGEST_ENUMERATOR = ObjCLifetime
  };
};
using ReferenceConversions = ReferenceConversionsScope::ReferenceConversions;

ReferenceCompareResult
CompareReferenceRelationship(SourceLocation Loc, QualType T1, QualType T2,
                             ReferenceConversions *Conv = nullptr);

ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
                               Expr *CastExpr, CastKind &CastKind,
                               ExprValueKind &VK, CXXCastPath &Path);

/// Force an expression with unknown-type to an expression of the
/// given type.
ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);

/// Type-check an expression that's being passed to an
/// __unknown_anytype parameter.
ExprResult checkUnknownAnyArg(SourceLocation callLoc,
                              Expr *result, QualType &paramType);

// CheckMatrixCast - Check type constraints for matrix casts.
// We allow casting between matrixes of the same dimensions i.e. when they
// have the same number of rows and column. Returns true if the cast is
// invalid.
bool CheckMatrixCast(SourceRange R, QualType DestTy, QualType SrcTy,
                     CastKind &Kind);

// CheckVectorCast - check type constraints for vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size.
// returns true if the cast is invalid
bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
                     CastKind &Kind);

/// Prepare `SplattedExpr` for a vector splat operation, adding
/// implicit casts if necessary.
ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);

// CheckExtVectorCast - check type constraints for extended vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size,
// or vectors and the element type of that vector.
// returns the cast expr
ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
                              CastKind &Kind);

ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
                                      SourceLocation LParenLoc,
                                      Expr *CastExpr,
                                      SourceLocation RParenLoc);

enum ARCConversionResult { ACR_okay, ACR_unbridged, ACR_error };

/// Checks for invalid conversions and casts between
/// retainable pointers and other pointer kinds for ARC and Weak.
ARCConversionResult CheckObjCConversion(SourceRange castRange,
                                        QualType castType, Expr *&op,
                                        CheckedConversionKind CCK,
                                        bool Diagnose = true,
                                        bool DiagnoseCFAudited = false,
                                        BinaryOperatorKind Opc = BO_PtrMemD
                                        );

Expr *stripARCUnbridgedCast(Expr *e);
void diagnoseARCUnbridgedCast(Expr *e);

bool CheckObjCARCUnavailableWeakConversion(QualType castType,
                                           QualType ExprType);

/// checkRetainCycles - Check whether an Objective-C message send
/// might create an obvious retain cycle.
void checkRetainCycles(ObjCMessageExpr *msg);
void checkRetainCycles(Expr *receiver, Expr *argument);
void checkRetainCycles(VarDecl *Var, Expr *Init);

/// checkUnsafeAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained type.
bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);

/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained expression.
void checkUnsafeExprAssigns(SourceLocation Loc, Expr *LHS, Expr *RHS);

/// CheckMessageArgumentTypes - Check types in an Obj-C message send.
/// \param Method - May be null.
/// \param [out] ReturnType - The return type of the send.
/// \return true iff there were any incompatible types.
bool CheckMessageArgumentTypes(const Expr *Receiver, QualType ReceiverType,
                               MultiExprArg Args, Selector Sel,
                               ArrayRef<SourceLocation> SelectorLocs,
                               ObjCMethodDecl *Method, bool isClassMessage,
                               bool isSuperMessage, SourceLocation lbrac,
                               SourceLocation rbrac, SourceRange RecRange,
                               QualType &ReturnType, ExprValueKind &VK);

/// Determine the result of a message send expression based on
/// the type of the receiver, the method expected to receive the message,
/// and the form of the message send.
QualType getMessageSendResultType(const Expr *Receiver, QualType ReceiverType,
                                  ObjCMethodDecl *Method, bool isClassMessage,
                                  bool isSuperMessage);

/// If the given expression involves a message send to a method
/// with a related result type, emit a note describing what happened.
void EmitRelatedResultTypeNote(const Expr *E);

/// Given that we had incompatible pointer types in a return
/// statement, check whether we're in a method with a related result
/// type, and if so, emit a note describing what happened.
void EmitRelatedResultTypeNoteForReturn(QualType destType);

class ConditionResult {
  Decl *ConditionVar;
  FullExprArg Condition;
  bool Invalid;
  bool HasKnownValue;
  bool KnownValue;

  friend class Sema;
  ConditionResult(Sema &S, Decl *ConditionVar, FullExprArg Condition,
                  bool IsConstexpr)
      : ConditionVar(ConditionVar), Condition(Condition), Invalid(false),
        HasKnownValue(IsConstexpr && Condition.get() &&
                      !Condition.get()->isValueDependent()),
        KnownValue(HasKnownValue &&
                   !!Condition.get()->EvaluateKnownConstInt(S.Context)) {}
  explicit ConditionResult(bool Invalid)
      : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid),
        HasKnownValue(false), KnownValue(false) {}

public:
  ConditionResult() : ConditionResult(false) {}
  bool isInvalid() const { return Invalid; }
  std::pair<VarDecl *, Expr *> get() const {
    return std::make_pair(cast_or_null<VarDecl>(ConditionVar),
                          Condition.get());
  }
  llvm::Optional<bool> getKnownValue() const {
    if (!HasKnownValue)
      return None;
    return KnownValue;
  }
};
static ConditionResult ConditionError() { return ConditionResult(true); }

enum class ConditionKind {
  Boolean,     ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
  ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
  Switch       ///< An integral condition for a 'switch' statement.
};

ConditionResult ActOnCondition(Scope *S, SourceLocation Loc,
                               Expr *SubExpr, ConditionKind CK);

ConditionResult ActOnConditionVariable(Decl *ConditionVar,
                                       SourceLocation StmtLoc,
                                       ConditionKind CK);

DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);

ExprResult CheckConditionVariable(VarDecl *ConditionVar,
                                  SourceLocation StmtLoc,
                                  ConditionKind CK);
ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);

/// CheckBooleanCondition - Diagnose problems involving the use of
/// the given expression as a boolean condition (e.g. in an if
/// statement).  Also performs the standard function and array
/// decays, possibly changing the input variable.
///
/// \param Loc - A location associated with the condition, e.g. the
/// 'if' keyword.
/// \return true iff there were any errors
ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
                                 bool IsConstexpr = false);

/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
/// found in an explicit(bool) specifier.
ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);

/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
/// Returns true if the explicit specifier is now resolved.
bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);

/// DiagnoseAssignmentAsCondition - Given that an expression is
/// being used as a boolean condition, warn if it's an assignment.
void DiagnoseAssignmentAsCondition(Expr *E);

/// Redundant parentheses over an equality comparison can indicate
/// that the user intended an assignment used as condition.
void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);

/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
ExprResult CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr = false);

/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
/// the specified width and sign.  If an overflow occurs, detect it and emit
/// the specified diagnostic.
void ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &OldVal,
                                        unsigned NewWidth, bool NewSign,
                                        SourceLocation Loc, unsigned DiagID);

/// Checks that the Objective-C declaration is declared in the global scope.
/// Emits an error and marks the declaration as invalid if it's not declared
/// in the global scope.
bool CheckObjCDeclScope(Decl *D);

/// Abstract base class used for diagnosing integer constant
/// expression violations.
class VerifyICEDiagnoser {
public:
  bool Suppress;

  VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) { }

  virtual SemaDiagnosticBuilder
  diagnoseNotICEType(Sema &S, SourceLocation Loc, QualType T);
  virtual SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
                                               SourceLocation Loc) = 0;
  virtual SemaDiagnosticBuilder diagnoseFold(Sema &S, SourceLocation Loc);
  virtual ~VerifyICEDiagnoser() {}
};

enum AllowFoldKind {
  NoFold,
  AllowFold,
};

/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
/// and reports the appropriate diagnostics. Returns false on success.
/// Can optionally return the value of the expression.
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           VerifyICEDiagnoser &Diagnoser,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           unsigned DiagID,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E,
                                           llvm::APSInt *Result = nullptr,
                                           AllowFoldKind CanFold = NoFold);
ExprResult VerifyIntegerConstantExpression(Expr *E,
                                           AllowFoldKind CanFold = NoFold) {
  return VerifyIntegerConstantExpression(E, nullptr, CanFold);
}

/// VerifyBitField - verifies that a bit field expression is an ICE and has
/// the correct width, and that the field type is valid.
/// Returns false on success.
/// Can optionally return whether the bit-field is of width 0
ExprResult VerifyBitField(SourceLocation FieldLoc, IdentifierInfo *FieldName,
                          QualType FieldTy, bool IsMsStruct,
                          Expr *BitWidth, bool *ZeroWidth = nullptr);

12039private:
unsigned ForceCUDAHostDeviceDepth = 0;

12042public:
/// Increments our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  So long as this count is greater
/// than zero, all functions encountered will be __host__ __device__.
void PushForceCUDAHostDevice();

/// Decrements our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  Returns false if the count is 0
/// before incrementing, so you can emit an error.
bool PopForceCUDAHostDevice();

/// Diagnostics that are emitted only if we discover that the given function
/// must be codegen'ed.  Because handling these correctly adds overhead to
/// compilation, this is currently only enabled for CUDA compilations.
llvm::DenseMap<CanonicalDeclPtr<FunctionDecl>,
               std::vector<PartialDiagnosticAt>>
    DeviceDeferredDiags;

/// A pair of a canonical FunctionDecl and a SourceLocation.  When used as the
/// key in a hashtable, both the FD and location are hashed.
struct FunctionDeclAndLoc {
  CanonicalDeclPtr<FunctionDecl> FD;
  SourceLocation Loc;
};

/// FunctionDecls and SourceLocations for which CheckCUDACall has emitted a
/// (maybe deferred) "bad call" diagnostic.  We use this to avoid emitting the
/// same deferred diag twice.
llvm::DenseSet<FunctionDeclAndLoc> LocsWithCUDACallDiags;

/// An inverse call graph, mapping known-emitted functions to one of their
/// known-emitted callers (plus the location of the call).
///
/// Functions that we can tell a priori must be emitted aren't added to this
/// map.
llvm::DenseMap</* Callee = */ CanonicalDeclPtr<FunctionDecl>,
               /* Caller = */ FunctionDeclAndLoc>
    DeviceKnownEmittedFns;

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurContext is a __host__ function, does not emit any diagnostics
///   unless \p EmitOnBothSides is true.
/// - If CurContext is a __device__ or __global__ function, emits the
///   diagnostics immediately.
/// - If CurContext is a __host__ __device__ function and we are compiling for
///   the device, creates a diagnostic which is emitted if and when we realize
///   that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in CUDA device code.
///  if (CUDADiagIfDeviceCode(Loc, diag::err_cuda_vla) << CurrentCUDATarget())
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder CUDADiagIfDeviceCode(SourceLocation Loc,
                                           unsigned DiagID);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as host code".
///
/// Same as CUDADiagIfDeviceCode, with "host" and "device" switched.
SemaDiagnosticBuilder CUDADiagIfHostCode(SourceLocation Loc, unsigned DiagID);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the device, emits the diagnostics immediately.
/// - If CurContext is a non-`declare target` function and we are compiling
///   for the device, creates a diagnostic which is emitted if and when we
///   realize that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPDeviceCode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder
diagIfOpenMPDeviceCode(SourceLocation Loc, unsigned DiagID, FunctionDecl *FD);

/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as host code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the host, emits the diagnostics immediately.
/// - If CurContext is a non-host function, just ignore it.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPHostode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
SemaDiagnosticBuilder diagIfOpenMPHostCode(SourceLocation Loc,
                                           unsigned DiagID, FunctionDecl *FD);

SemaDiagnosticBuilder targetDiag(SourceLocation Loc, unsigned DiagID,
                                 FunctionDecl *FD = nullptr);
SemaDiagnosticBuilder targetDiag(SourceLocation Loc,
                                 const PartialDiagnostic &PD,
                                 FunctionDecl *FD = nullptr) {
  return targetDiag(Loc, PD.getDiagID(), FD) << PD;
}

/// Check if the expression is allowed to be used in expressions for the
/// offloading devices.
void checkDeviceDecl(ValueDecl *D, SourceLocation Loc);

enum CUDAFunctionTarget {
  CFT_Device,
  CFT_Global,
  CFT_Host,
  CFT_HostDevice,
  CFT_InvalidTarget
};

/// Determines whether the given function is a CUDA device/host/kernel/etc.
/// function.
///
/// Use this rather than examining the function's attributes yourself -- you
/// will get it wrong.  Returns CFT_Host if D is null.
CUDAFunctionTarget IdentifyCUDATarget(const FunctionDecl *D,
                                      bool IgnoreImplicitHDAttr = false);
CUDAFunctionTarget IdentifyCUDATarget(const ParsedAttributesView &Attrs);

enum CUDAVariableTarget {
  CVT_Device,  /// Emitted on device side with a shadow variable on host side
  CVT_Host,    /// Emitted on host side only
  CVT_Both,    /// Emitted on both sides with different addresses
  CVT_Unified, /// Emitted as a unified address, e.g. managed variables
};
/// Determines whether the given variable is emitted on host or device side.
CUDAVariableTarget IdentifyCUDATarget(const VarDecl *D);

/// Gets the CUDA target for the current context.
CUDAFunctionTarget CurrentCUDATarget() {
  return IdentifyCUDATarget(dyn_cast<FunctionDecl>(CurContext));
}

static bool isCUDAImplicitHostDeviceFunction(const FunctionDecl *D);

// CUDA function call preference. Must be ordered numerically from
// worst to best.
enum CUDAFunctionPreference {
  CFP_Never,      // Invalid caller/callee combination.
  CFP_WrongSide,  // Calls from host-device to host or device
                  // function that do not match current compilation
                  // mode.
  CFP_HostDevice, // Any calls to host/device functions.
  CFP_SameSide,   // Calls from host-device to host or device
                  // function matching current compilation mode.
  CFP_Native,     // host-to-host or device-to-device calls.
};

/// Identifies relative preference of a given Caller/Callee
/// combination, based on their host/device attributes.
/// \param Caller function which needs address of \p Callee.
///               nullptr in case of global context.
/// \param Callee target function
///
/// \returns preference value for particular Caller/Callee combination.
CUDAFunctionPreference IdentifyCUDAPreference(const FunctionDecl *Caller,
                                              const FunctionDecl *Callee);

/// Determines whether Caller may invoke Callee, based on their CUDA
/// host/device attributes.  Returns false if the call is not allowed.
///
/// Note: Will return true for CFP_WrongSide calls.  These may appear in
/// semantically correct CUDA programs, but only if they're never codegen'ed.
bool IsAllowedCUDACall(const FunctionDecl *Caller,
                       const FunctionDecl *Callee) {
  return IdentifyCUDAPreference(Caller, Callee) != CFP_Never;
}

/// May add implicit CUDAHostAttr and CUDADeviceAttr attributes to FD,
/// depending on FD and the current compilation settings.
void maybeAddCUDAHostDeviceAttrs(FunctionDecl *FD,
                                 const LookupResult &Previous);

/// May add implicit CUDAConstantAttr attribute to VD, depending on VD
/// and current compilation settings.
void MaybeAddCUDAConstantAttr(VarDecl *VD);

12228public:
/// Check whether we're allowed to call Callee from the current context.
///
/// - If the call is never allowed in a semantically-correct program
///   (CFP_Never), emits an error and returns false.
///
/// - If the call is allowed in semantically-correct programs, but only if
///   it's never codegen'ed (CFP_WrongSide), creates a deferred diagnostic to
///   be emitted if and when the caller is codegen'ed, and returns true.
///
///   Will only create deferred diagnostics for a given SourceLocation once,
///   so you can safely call this multiple times without generating duplicate
///   deferred errors.
///
/// - Otherwise, returns true without emitting any diagnostics.
bool CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee);

void CUDACheckLambdaCapture(CXXMethodDecl *D, const sema::Capture &Capture);

/// Set __device__ or __host__ __device__ attributes on the given lambda
/// operator() method.
///
/// CUDA lambdas by default is host device function unless it has explicit
/// host or device attribute.
void CUDASetLambdaAttrs(CXXMethodDecl *Method);

/// Finds a function in \p Matches with highest calling priority
/// from \p Caller context and erases all functions with lower
/// calling priority.
void EraseUnwantedCUDAMatches(
    const FunctionDecl *Caller,
    SmallVectorImpl<std::pair<DeclAccessPair, FunctionDecl *>> &Matches);

/// Given a implicit special member, infer its CUDA target from the
/// calls it needs to make to underlying base/field special members.
/// \param ClassDecl the class for which the member is being created.
/// \param CSM the kind of special member.
/// \param MemberDecl the special member itself.
/// \param ConstRHS true if this is a copy operation with a const object on
///        its RHS.
/// \param Diagnose true if this call should emit diagnostics.
/// \return true if there was an error inferring.
/// The result of this call is implicit CUDA target attribute(s) attached to
/// the member declaration.
bool inferCUDATargetForImplicitSpecialMember(CXXRecordDecl *ClassDecl,
                                             CXXSpecialMember CSM,
                                             CXXMethodDecl *MemberDecl,
                                             bool ConstRHS,
                                             bool Diagnose);

/// \return true if \p CD can be considered empty according to CUDA
/// (E.2.3.1 in CUDA 7.5 Programming guide).
bool isEmptyCudaConstructor(SourceLocation Loc, CXXConstructorDecl *CD);
bool isEmptyCudaDestructor(SourceLocation Loc, CXXDestructorDecl *CD);

// \brief Checks that initializers of \p Var satisfy CUDA restrictions. In
// case of error emits appropriate diagnostic and invalidates \p Var.
//
// \details CUDA allows only empty constructors as initializers for global
// variables (see E.2.3.1, CUDA 7.5). The same restriction also applies to all
// __shared__ variables whether they are local or not (they all are implicitly
// static in CUDA). One exception is that CUDA allows constant initializers
// for __constant__ and __device__ variables.
void checkAllowedCUDAInitializer(VarDecl *VD);

/// Check whether NewFD is a valid overload for CUDA. Emits
/// diagnostics and invalidates NewFD if not.
void checkCUDATargetOverload(FunctionDecl *NewFD,
                             const LookupResult &Previous);
/// Copies target attributes from the template TD to the function FD.
void inheritCUDATargetAttrs(FunctionDecl *FD, const FunctionTemplateDecl &TD);

/// Returns the name of the launch configuration function.  This is the name
/// of the function that will be called to configure kernel call, with the
/// parameters specified via <<<>>>.
std::string getCudaConfigureFuncName() const;

/// \name Code completion
//@{
/// Describes the context in which code completion occurs.
enum ParserCompletionContext {
  /// Code completion occurs at top-level or namespace context.
  PCC_Namespace,
  /// Code completion occurs within a class, struct, or union.
  PCC_Class,
  /// Code completion occurs within an Objective-C interface, protocol,
  /// or category.
  PCC_ObjCInterface,
  /// Code completion occurs within an Objective-C implementation or
  /// category implementation
  PCC_ObjCImplementation,
  /// Code completion occurs within the list of instance variables
  /// in an Objective-C interface, protocol, category, or implementation.
  PCC_ObjCInstanceVariableList,
  /// Code completion occurs following one or more template
  /// headers.
  PCC_Template,
  /// Code completion occurs following one or more template
  /// headers within a class.
  PCC_MemberTemplate,
  /// Code completion occurs within an expression.
  PCC_Expression,
  /// Code completion occurs within a statement, which may
  /// also be an expression or a declaration.
  PCC_Statement,
  /// Code completion occurs at the beginning of the
  /// initialization statement (or expression) in a for loop.
  PCC_ForInit,
  /// Code completion occurs within the condition of an if,
  /// while, switch, or for statement.
  PCC_Condition,
  /// Code completion occurs within the body of a function on a
  /// recovery path, where we do not have a specific handle on our position
  /// in the grammar.
  PCC_RecoveryInFunction,
  /// Code completion occurs where only a type is permitted.
  PCC_Type,
  /// Code completion occurs in a parenthesized expression, which
  /// might also be a type cast.
  PCC_ParenthesizedExpression,
  /// Code completion occurs within a sequence of declaration
  /// specifiers within a function, method, or block.
  PCC_LocalDeclarationSpecifiers
};

void CodeCompleteModuleImport(SourceLocation ImportLoc, ModuleIdPath Path);
void CodeCompleteOrdinaryName(Scope *S,
                              ParserCompletionContext CompletionContext);
void CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
                          bool AllowNonIdentifiers,
                          bool AllowNestedNameSpecifiers);

struct CodeCompleteExpressionData;
void CodeCompleteExpression(Scope *S,
                            const CodeCompleteExpressionData &Data);
void CodeCompleteExpression(Scope *S, QualType PreferredType,
                            bool IsParenthesized = false);
void CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base, Expr *OtherOpBase,
                                     SourceLocation OpLoc, bool IsArrow,
                                     bool IsBaseExprStatement,
                                     QualType PreferredType);
void CodeCompletePostfixExpression(Scope *S, ExprResult LHS,
                                   QualType PreferredType);
void CodeCompleteTag(Scope *S, unsigned TagSpec);
void CodeCompleteTypeQualifiers(DeclSpec &DS);
void CodeCompleteFunctionQualifiers(DeclSpec &DS, Declarator &D,
                                    const VirtSpecifiers *VS = nullptr);
void CodeCompleteBracketDeclarator(Scope *S);
void CodeCompleteCase(Scope *S);
/// Determines the preferred type of the current function argument, by
/// examining the signatures of all possible overloads.
/// Returns null if unknown or ambiguous, or if code completion is off.
///
/// If the code completion point has been reached, also reports the function
/// signatures that were considered.
///
/// FIXME: rename to GuessCallArgumentType to reduce confusion.
QualType ProduceCallSignatureHelp(Scope *S, Expr *Fn, ArrayRef<Expr *> Args,
                                  SourceLocation OpenParLoc);
QualType ProduceConstructorSignatureHelp(Scope *S, QualType Type,
                                         SourceLocation Loc,
                                         ArrayRef<Expr *> Args,
                                         SourceLocation OpenParLoc);
QualType ProduceCtorInitMemberSignatureHelp(Scope *S, Decl *ConstructorDecl,
                                            CXXScopeSpec SS,
                                            ParsedType TemplateTypeTy,
                                            ArrayRef<Expr *> ArgExprs,
                                            IdentifierInfo *II,
                                            SourceLocation OpenParLoc);
void CodeCompleteInitializer(Scope *S, Decl *D);
/// Trigger code completion for a record of \p BaseType. \p InitExprs are
/// expressions in the initializer list seen so far and \p D is the current
/// Designation being parsed.
void CodeCompleteDesignator(const QualType BaseType,
                            llvm::ArrayRef<Expr *> InitExprs,
                            const Designation &D);
void CodeCompleteAfterIf(Scope *S, bool IsBracedThen);

void CodeCompleteQualifiedId(Scope *S, CXXScopeSpec &SS, bool EnteringContext,
                             bool IsUsingDeclaration, QualType BaseType,
                             QualType PreferredType);
void CodeCompleteUsing(Scope *S);
void CodeCompleteUsingDirective(Scope *S);
void CodeCompleteNamespaceDecl(Scope *S);
void CodeCompleteNamespaceAliasDecl(Scope *S);
void CodeCompleteOperatorName(Scope *S);
void CodeCompleteConstructorInitializer(
                              Decl *Constructor,
                              ArrayRef<CXXCtorInitializer *> Initializers);

void CodeCompleteLambdaIntroducer(Scope *S, LambdaIntroducer &Intro,
                                  bool AfterAmpersand);
void CodeCompleteAfterFunctionEquals(Declarator &D);

void CodeCompleteObjCAtDirective(Scope *S);
void CodeCompleteObjCAtVisibility(Scope *S);
void CodeCompleteObjCAtStatement(Scope *S);
void CodeCompleteObjCAtExpression(Scope *S);
void CodeCompleteObjCPropertyFlags(Scope *S, ObjCDeclSpec &ODS);
void CodeCompleteObjCPropertyGetter(Scope *S);
void CodeCompleteObjCPropertySetter(Scope *S);
void CodeCompleteObjCPassingType(Scope *S, ObjCDeclSpec &DS,
                                 bool IsParameter);
void CodeCompleteObjCMessageReceiver(Scope *S);
void CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression);
void CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression,
                                  bool IsSuper = false);
void CodeCompleteObjCInstanceMessage(Scope *S, Expr *Receiver,
                                     ArrayRef<IdentifierInfo *> SelIdents,
                                     bool AtArgumentExpression,
                                     ObjCInterfaceDecl *Super = nullptr);
void CodeCompleteObjCForCollection(Scope *S,
                                   DeclGroupPtrTy IterationVar);
void CodeCompleteObjCSelector(Scope *S,
                              ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCProtocolReferences(
                                       ArrayRef<IdentifierLocPair> Protocols);
void CodeCompleteObjCProtocolDecl(Scope *S);
void CodeCompleteObjCInterfaceDecl(Scope *S);
void CodeCompleteObjCSuperclass(Scope *S,
                                IdentifierInfo *ClassName,
                                SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationDecl(Scope *S);
void CodeCompleteObjCInterfaceCategory(Scope *S,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationCategory(Scope *S,
                                            IdentifierInfo *ClassName,
                                            SourceLocation ClassNameLoc);
void CodeCompleteObjCPropertyDefinition(Scope *S);
void CodeCompleteObjCPropertySynthesizeIvar(Scope *S,
                                            IdentifierInfo *PropertyName);
void CodeCompleteObjCMethodDecl(Scope *S, Optional<bool> IsInstanceMethod,
                                ParsedType ReturnType);
void CodeCompleteObjCMethodDeclSelector(Scope *S,
                                        bool IsInstanceMethod,
                                        bool AtParameterName,
                                        ParsedType ReturnType,
                                        ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCClassPropertyRefExpr(Scope *S, IdentifierInfo &ClassName,
                                          SourceLocation ClassNameLoc,
                                          bool IsBaseExprStatement);
void CodeCompletePreprocessorDirective(bool InConditional);
void CodeCompleteInPreprocessorConditionalExclusion(Scope *S);
void CodeCompletePreprocessorMacroName(bool IsDefinition);
void CodeCompletePreprocessorExpression();
void CodeCompletePreprocessorMacroArgument(Scope *S,
                                           IdentifierInfo *Macro,
                                           MacroInfo *MacroInfo,
                                           unsigned Argument);
void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled);
void CodeCompleteNaturalLanguage();
void CodeCompleteAvailabilityPlatformName();
void GatherGlobalCodeCompletions(CodeCompletionAllocator &Allocator,
                                 CodeCompletionTUInfo &CCTUInfo,
                SmallVectorImpl<CodeCompletionResult> &Results);
//@}

//===--------------------------------------------------------------------===//
// Extra semantic analysis beyond the C type system

12493public:
SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
                                              unsigned ByteNo) const;

12497private:
void CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                      const ArraySubscriptExpr *ASE=nullptr,
                      bool AllowOnePastEnd=true, bool IndexNegated=false);
void CheckArrayAccess(const Expr *E);
// Used to grab the relevant information from a FormatAttr and a
// FunctionDeclaration.
struct FormatStringInfo {
  unsigned FormatIdx;
  unsigned FirstDataArg;
  bool HasVAListArg;
};

static bool getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
                                FormatStringInfo *FSI);
bool CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
                       const FunctionProtoType *Proto);
bool CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation loc,
                         ArrayRef<const Expr *> Args);
bool CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
                      const FunctionProtoType *Proto);
bool CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto);
void CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
                          ArrayRef<const Expr *> Args,
                          const FunctionProtoType *Proto, SourceLocation Loc);

void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
                       StringRef ParamName, QualType ArgTy, QualType ParamTy);

void checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
               const Expr *ThisArg, ArrayRef<const Expr *> Args,
               bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
               VariadicCallType CallType);

bool CheckObjCString(Expr *Arg);
ExprResult CheckOSLogFormatStringArg(Expr *Arg);

ExprResult CheckBuiltinFunctionCall(FunctionDecl *FDecl,
                                    unsigned BuiltinID, CallExpr *TheCall);

bool CheckTSBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                CallExpr *TheCall);

void checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD, CallExpr *TheCall);

bool CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
                                  unsigned MaxWidth);
bool CheckNeonBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                  CallExpr *TheCall);
bool CheckMVEBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckSVEBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckCDEBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckARMCoprocessorImmediate(const TargetInfo &TI, const Expr *CoprocArg,
                                  bool WantCDE);
bool CheckARMBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);

bool CheckAArch64BuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                     CallExpr *TheCall);
bool CheckBPFBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinArgument(unsigned BuiltinID, CallExpr *TheCall);
bool CheckMipsBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                  CallExpr *TheCall);
bool CheckMipsBuiltinCpu(const TargetInfo &TI, unsigned BuiltinID,
                         CallExpr *TheCall);
bool CheckMipsBuiltinArgument(unsigned BuiltinID, CallExpr *TheCall);
bool CheckSystemZBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinRoundingOrSAE(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinGatherScatterScale(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinTileArguments(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinTileArgumentsRange(CallExpr *TheCall,
                                       ArrayRef<int> ArgNums);
bool CheckX86BuiltinTileDuplicate(CallExpr *TheCall, ArrayRef<int> ArgNums);
bool CheckX86BuiltinTileRangeAndDuplicate(CallExpr *TheCall,
                                          ArrayRef<int> ArgNums);
bool CheckX86BuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckPPCBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                 CallExpr *TheCall);
bool CheckAMDGCNBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckRISCVLMUL(CallExpr *TheCall, unsigned ArgNum);
bool CheckRISCVBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                   CallExpr *TheCall);

bool SemaBuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
bool SemaBuiltinVAStartARMMicrosoft(CallExpr *Call);
bool SemaBuiltinUnorderedCompare(CallExpr *TheCall);
bool SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs);
bool SemaBuiltinComplex(CallExpr *TheCall);
bool SemaBuiltinVSX(CallExpr *TheCall);
bool SemaBuiltinOSLogFormat(CallExpr *TheCall);
bool SemaValueIsRunOfOnes(CallExpr *TheCall, unsigned ArgNum);

12592public:
// Used by C++ template instantiation.
ExprResult SemaBuiltinShuffleVector(CallExpr *TheCall);
ExprResult SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
                                 SourceLocation BuiltinLoc,
                                 SourceLocation RParenLoc);

12599private:
bool SemaBuiltinPrefetch(CallExpr *TheCall);
bool SemaBuiltinAllocaWithAlign(CallExpr *TheCall);
bool SemaBuiltinArithmeticFence(CallExpr *TheCall);
bool SemaBuiltinAssume(CallExpr *TheCall);
bool SemaBuiltinAssumeAligned(CallExpr *TheCall);
bool SemaBuiltinLongjmp(CallExpr *TheCall);
bool SemaBuiltinSetjmp(CallExpr *TheCall);
ExprResult SemaBuiltinAtomicOverloaded(ExprResult TheCallResult);
ExprResult SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult);
ExprResult SemaAtomicOpsOverloaded(ExprResult TheCallResult,
                                   AtomicExpr::AtomicOp Op);
ExprResult SemaBuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
                                                  bool IsDelete);
bool SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
                            llvm::APSInt &Result);
bool SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, int Low,
                                 int High, bool RangeIsError = true);
bool SemaBuiltinConstantArgMultiple(CallExpr *TheCall, int ArgNum,
                                    unsigned Multiple);
bool SemaBuiltinConstantArgPower2(CallExpr *TheCall, int ArgNum);
bool SemaBuiltinConstantArgShiftedByte(CallExpr *TheCall, int ArgNum,
                                       unsigned ArgBits);
bool SemaBuiltinConstantArgShiftedByteOrXXFF(CallExpr *TheCall, int ArgNum,
                                             unsigned ArgBits);
bool SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
                              int ArgNum, unsigned ExpectedFieldNum,
                              bool AllowName);
bool SemaBuiltinARMMemoryTaggingCall(unsigned BuiltinID, CallExpr *TheCall);
bool SemaBuiltinPPCMMACall(CallExpr *TheCall, const char *TypeDesc);

bool CheckPPCMMAType(QualType Type, SourceLocation TypeLoc);

// Matrix builtin handling.
ExprResult SemaBuiltinMatrixTranspose(CallExpr *TheCall,
                                      ExprResult CallResult);
ExprResult SemaBuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
                                            ExprResult CallResult);
ExprResult SemaBuiltinMatrixColumnMajorStore(CallExpr *TheCall,
                                             ExprResult CallResult);

12640public:
enum FormatStringType {
  FST_Scanf,
  FST_Printf,
  FST_NSString,
  FST_Strftime,
  FST_Strfmon,
  FST_Kprintf,
  FST_FreeBSDKPrintf,
  FST_OSTrace,
  FST_OSLog,
  FST_Syslog,
  FST_Unknown
};
static FormatStringType GetFormatStringType(const FormatAttr *Format);

bool FormatStringHasSArg(const StringLiteral *FExpr);

static bool GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx);

12660private:
bool CheckFormatArguments(const FormatAttr *Format,
                          ArrayRef<const Expr *> Args,
                          bool IsCXXMember,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange Range,
                          llvm::SmallBitVector &CheckedVarArgs);
bool CheckFormatArguments(ArrayRef<const Expr *> Args,
                          bool HasVAListArg, unsigned format_idx,
                          unsigned firstDataArg, FormatStringType Type,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange range,
                          llvm::SmallBitVector &CheckedVarArgs);

void CheckAbsoluteValueFunction(const CallExpr *Call,
                                const FunctionDecl *FDecl);

void CheckMaxUnsignedZero(const CallExpr *Call, const FunctionDecl *FDecl);

void CheckMemaccessArguments(const CallExpr *Call,
                             unsigned BId,
                             IdentifierInfo *FnName);

void CheckStrlcpycatArguments(const CallExpr *Call,
                              IdentifierInfo *FnName);

void CheckStrncatArguments(const CallExpr *Call,
                           IdentifierInfo *FnName);

void CheckFreeArguments(const CallExpr *E);

void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
                        SourceLocation ReturnLoc,
                        bool isObjCMethod = false,
                        const AttrVec *Attrs = nullptr,
                        const FunctionDecl *FD = nullptr);

12697public:
void CheckFloatComparison(SourceLocation Loc, Expr *LHS, Expr *RHS);

12700private:
void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation());
void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
void CheckForIntOverflow(Expr *E);
void CheckUnsequencedOperations(const Expr *E);

/// Perform semantic checks on a completed expression. This will either
/// be a full-expression or a default argument expression.
void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation(),
                        bool IsConstexpr = false);

void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
                                 Expr *Init);

/// Check if there is a field shadowing.
void CheckShadowInheritedFields(const SourceLocation &Loc,
                                DeclarationName FieldName,
                                const CXXRecordDecl *RD,
                                bool DeclIsField = true);

/// Check if the given expression contains 'break' or 'continue'
/// statement that produces control flow different from GCC.
void CheckBreakContinueBinding(Expr *E);

/// Check whether receiver is mutable ObjC container which
/// attempts to add itself into the container
void CheckObjCCircularContainer(ObjCMessageExpr *Message);

void CheckTCBEnforcement(const CallExpr *TheCall, const FunctionDecl *Callee);

void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
                               bool DeleteWasArrayForm);
12733public:
/// Register a magic integral constant to be used as a type tag.
void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
                                uint64_t MagicValue, QualType Type,
                                bool LayoutCompatible, bool MustBeNull);

struct TypeTagData {
  TypeTagData() {}

  TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull) :
      Type(Type), LayoutCompatible(LayoutCompatible),
      MustBeNull(MustBeNull)
  {}

  QualType Type;

  /// If true, \c Type should be compared with other expression's types for
  /// layout-compatibility.
  unsigned LayoutCompatible : 1;
  unsigned MustBeNull : 1;
};

/// A pair of ArgumentKind identifier and magic value.  This uniquely
/// identifies the magic value.
typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;

12759private:
/// A map from magic value to type information.
std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
    TypeTagForDatatypeMagicValues;

/// Peform checks on a call of a function with argument_with_type_tag
/// or pointer_with_type_tag attributes.
void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
                              const ArrayRef<const Expr *> ExprArgs,
                              SourceLocation CallSiteLoc);

/// Check if we are taking the address of a packed field
/// as this may be a problem if the pointer value is dereferenced.
void CheckAddressOfPackedMember(Expr *rhs);

/// The parser's current scope.
///
/// The parser maintains this state here.
Scope *CurScope;

mutable IdentifierInfo *Ident_super;
mutable IdentifierInfo *Ident___float128;

/// Nullability type specifiers.
IdentifierInfo *Ident__Nonnull = nullptr;
IdentifierInfo *Ident__Nullable = nullptr;
IdentifierInfo *Ident__Nullable_result = nullptr;
IdentifierInfo *Ident__Null_unspecified = nullptr;

IdentifierInfo *Ident_NSError = nullptr;

/// The handler for the FileChanged preprocessor events.
///
/// Used for diagnostics that implement custom semantic analysis for #include
/// directives, like -Wpragma-pack.
sema::SemaPPCallbacks *SemaPPCallbackHandler;

12796protected:
friend class Parser;
friend class InitializationSequence;
friend class ASTReader;
friend class ASTDeclReader;
friend class ASTWriter;

12803public:
/// Retrieve the keyword associated
IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);

/// The struct behind the CFErrorRef pointer.
RecordDecl *CFError = nullptr;
bool isCFError(RecordDecl *D);

/// Retrieve the identifier "NSError".
IdentifierInfo *getNSErrorIdent();

/// Retrieve the parser's current scope.
///
/// This routine must only be used when it is certain that semantic analysis
/// and the parser are in precisely the same context, which is not the case
/// when, e.g., we are performing any kind of template instantiation.
/// Therefore, the only safe places to use this scope are in the parser
/// itself and in routines directly invoked from the parser and *never* from
/// template substitution or instantiation.
Scope *getCurScope() const { return CurScope; }

void incrementMSManglingNumber() const {
  return CurScope->incrementMSManglingNumber();
}

IdentifierInfo *getSuperIdentifier() const;
IdentifierInfo *getFloat128Identifier() const;

Decl *getObjCDeclContext() const;

DeclContext *getCurLexicalContext() const {
  return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
}

const DeclContext *getCurObjCLexicalContext() const {
  const DeclContext *DC = getCurLexicalContext();
  // A category implicitly has the attribute of the interface.
  if (const ObjCCategoryDecl *CatD = dyn_cast<ObjCCategoryDecl>(DC))
    DC = CatD->getClassInterface();
  return DC;
}

/// Determine the number of levels of enclosing template parameters. This is
/// only usable while parsing. Note that this does not include dependent
/// contexts in which no template parameters have yet been declared, such as
/// in a terse function template or generic lambda before the first 'auto' is
/// encountered.
unsigned getTemplateDepth(Scope *S) const;

/// To be used for checking whether the arguments being passed to
/// function exceeds the number of parameters expected for it.
static bool TooManyArguments(size_t NumParams, size_t NumArgs,
                             bool PartialOverloading = false) {
  // We check whether we're just after a comma in code-completion.
  if (NumArgs > 0 && PartialOverloading)
    return NumArgs + 1 > NumParams; // If so, we view as an extra argument.
  return NumArgs > NumParams;
}

// Emitting members of dllexported classes is delayed until the class
// (including field initializers) is fully parsed.
SmallVector<CXXRecordDecl*, 4> DelayedDllExportClasses;
SmallVector<CXXMethodDecl*, 4> DelayedDllExportMemberFunctions;

12867private:
int ParsingClassDepth = 0;

class SavePendingParsedClassStateRAII {
public:
  SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }

  ~SavePendingParsedClassStateRAII() {
    assert(S.DelayedOverridingExceptionSpecChecks.empty() &&((void)0)
           "there shouldn't be any pending delayed exception spec checks")((void)0);
    assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&((void)0)
           "there shouldn't be any pending delayed exception spec checks")((void)0);
    swapSavedState();
  }

private:
  Sema &S;
  decltype(DelayedOverridingExceptionSpecChecks)
      SavedOverridingExceptionSpecChecks;
  decltype(DelayedEquivalentExceptionSpecChecks)
      SavedEquivalentExceptionSpecChecks;

  void swapSavedState() {
    SavedOverridingExceptionSpecChecks.swap(
        S.DelayedOverridingExceptionSpecChecks);
    SavedEquivalentExceptionSpecChecks.swap(
        S.DelayedEquivalentExceptionSpecChecks);
  }
};

/// Helper class that collects misaligned member designations and
/// their location info for delayed diagnostics.
struct MisalignedMember {
  Expr *E;
  RecordDecl *RD;
  ValueDecl *MD;
  CharUnits Alignment;

  MisalignedMember() : E(), RD(), MD(), Alignment() {}
  MisalignedMember(Expr *E, RecordDecl *RD, ValueDecl *MD,
                   CharUnits Alignment)
      : E(E), RD(RD), MD(MD), Alignment(Alignment) {}
  explicit MisalignedMember(Expr *E)
      : MisalignedMember(E, nullptr, nullptr, CharUnits()) {}

  bool operator==(const MisalignedMember &m) { return this->E == m.E; }
};
/// Small set of gathered accesses to potentially misaligned members
/// due to the packed attribute.
SmallVector<MisalignedMember, 4> MisalignedMembers;

/// Adds an expression to the set of gathered misaligned members.
void AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD, ValueDecl *MD,
                                   CharUnits Alignment);

12922public:
/// Diagnoses the current set of gathered accesses. This typically
/// happens at full expression level. The set is cleared after emitting the
/// diagnostics.
void DiagnoseMisalignedMembers();

/// This function checks if the expression is in the sef of potentially
/// misaligned members and it is converted to some pointer type T with lower
/// or equal alignment requirements. If so it removes it. This is used when
/// we do not want to diagnose such misaligned access (e.g. in conversions to
/// void*).
void DiscardMisalignedMemberAddress(const Type *T, Expr *E);

/// This function calls Action when it determines that E designates a
/// misaligned member due to the packed attribute. This is used to emit
/// local diagnostics like in reference binding.
void RefersToMemberWithReducedAlignment(
    Expr *E,
    llvm::function_ref<void(Expr *, RecordDecl *, FieldDecl *, CharUnits)>
        Action);

/// Describes the reason a calling convention specification was ignored, used
/// for diagnostics.
enum class CallingConventionIgnoredReason {
  ForThisTarget = 0,
  VariadicFunction,
  ConstructorDestructor,
  BuiltinFunction
};
/// Creates a SemaDiagnosticBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurLexicalContext is a kernel function or it is known that the
///   function will be emitted for the device, emits the diagnostics
///   immediately.
/// - If CurLexicalContext is a function and we are compiling
///   for the device, but we don't know that this function will be codegen'ed
///   for devive yet, creates a diagnostic which is emitted if and when we
///   realize that the function will be codegen'ed.
///
/// Example usage:
///
/// Diagnose __float128 type usage only from SYCL device code if the current
/// target doesn't support it
/// if (!S.Context.getTargetInfo().hasFloat128Type() &&
///     S.getLangOpts().SYCLIsDevice)
///   SYCLDiagIfDeviceCode(Loc, diag::err_type_unsupported) << "__float128";
SemaDiagnosticBuilder SYCLDiagIfDeviceCode(SourceLocation Loc,
                                           unsigned DiagID);

/// Check whether we're allowed to call Callee from the current context.
///
/// - If the call is never allowed in a semantically-correct program
///   emits an error and returns false.
///
/// - If the call is allowed in semantically-correct programs, but only if
///   it's never codegen'ed, creates a deferred diagnostic to be emitted if
///   and when the caller is codegen'ed, and returns true.
///
/// - Otherwise, returns true without emitting any diagnostics.
///
/// Adds Callee to DeviceCallGraph if we don't know if its caller will be
/// codegen'ed yet.
bool checkSYCLDeviceFunction(SourceLocation Loc, FunctionDecl *Callee);
12986};

12988/// RAII object that enters a new expression evaluation context.
12989class EnterExpressionEvaluationContext {
Sema &Actions;
bool Entered = true;

12993public:
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Decl *LambdaContextDecl = nullptr,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other,
    bool ShouldEnter = true)
    : Actions(Actions), Entered(ShouldEnter) {
  if (Entered)
    Actions.PushExpressionEvaluationContext(NewContext, LambdaContextDecl,
                                            ExprContext);
}
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Sema::ReuseLambdaContextDecl_t,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other)
    : Actions(Actions) {
  Actions.PushExpressionEvaluationContext(
      NewContext, Sema::ReuseLambdaContextDecl, ExprContext);
}

enum InitListTag { InitList };
EnterExpressionEvaluationContext(Sema &Actions, InitListTag,
                                 bool ShouldEnter = true)
    : Actions(Actions), Entered(false) {
  // In C++11 onwards, narrowing checks are performed on the contents of
  // braced-init-lists, even when they occur within unevaluated operands.
  // Therefore we still need to instantiate constexpr functions used in such
  // a context.
  if (ShouldEnter && Actions.isUnevaluatedContext() &&
      Actions.getLangOpts().CPlusPlus11) {
    Actions.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::UnevaluatedList);
    Entered = true;
  }
}

~EnterExpressionEvaluationContext() {
  if (Entered)
    Actions.PopExpressionEvaluationContext();
}
13035};

13037DeductionFailureInfo
13038MakeDeductionFailureInfo(ASTContext &Context, Sema::TemplateDeductionResult TDK,
                       sema::TemplateDeductionInfo &Info);

13041/// Contains a late templated function.
13042/// Will be parsed at the end of the translation unit, used by Sema & Parser.
13043struct LateParsedTemplate {
CachedTokens Toks;
/// The template function declaration to be late parsed.
Decl *D;
13047};

13049template <>
13050void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
                                               PragmaMsStackAction Action,
                                               llvm::StringRef StackSlotLabel,
                                               AlignPackInfo Value);

13055} // end namespace clang

13057namespace llvm {
13058// Hash a FunctionDeclAndLoc by looking at both its FunctionDecl and its
13059// SourceLocation.
13060template <> struct DenseMapInfo<clang::Sema::FunctionDeclAndLoc> {
using FunctionDeclAndLoc = clang::Sema::FunctionDeclAndLoc;
using FDBaseInfo = DenseMapInfo<clang::CanonicalDeclPtr<clang::FunctionDecl>>;

static FunctionDeclAndLoc getEmptyKey() {
  return {FDBaseInfo::getEmptyKey(), clang::SourceLocation()};
}

static FunctionDeclAndLoc getTombstoneKey() {
  return {FDBaseInfo::getTombstoneKey(), clang::SourceLocation()};
}

static unsigned getHashValue(const FunctionDeclAndLoc &FDL) {
  return hash_combine(FDBaseInfo::getHashValue(FDL.FD),
                      FDL.Loc.getHashValue());
}

static bool isEqual(const FunctionDeclAndLoc &LHS,
                    const FunctionDeclAndLoc &RHS) {
  return LHS.FD == RHS.FD && LHS.Loc == RHS.Loc;
}
13081};
13082} // namespace llvm

13084#endif