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

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
Warning:	line 5533, column 7 Called C++ object pointer is null

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

→

1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl 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 for declarations.
9//
10//===----------------------------------------------------------------------===/

12#include "TreeTransform.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTMutationListener.h"
16#include "clang/AST/DeclTemplate.h"
17#include "clang/AST/DeclVisitor.h"
18#include "clang/AST/DependentDiagnostic.h"
19#include "clang/AST/Expr.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/PrettyDeclStackTrace.h"
22#include "clang/AST/TypeLoc.h"
23#include "clang/Basic/SourceManager.h"
24#include "clang/Basic/TargetInfo.h"
25#include "clang/Sema/Initialization.h"
26#include "clang/Sema/Lookup.h"
27#include "clang/Sema/ScopeInfo.h"
28#include "clang/Sema/SemaInternal.h"
29#include "clang/Sema/Template.h"
30#include "clang/Sema/TemplateInstCallback.h"
31#include "llvm/Support/TimeProfiler.h"

33using namespace clang;

35static bool isDeclWithinFunction(const Decl *D) {
const DeclContext *DC = D->getDeclContext();
if (DC->isFunctionOrMethod())
  return true;

if (DC->isRecord())
  return cast<CXXRecordDecl>(DC)->isLocalClass();

return false;
44}

46template<typename DeclT>
47static bool SubstQualifier(Sema &SemaRef, const DeclT *OldDecl, DeclT *NewDecl,
                         const MultiLevelTemplateArgumentList &TemplateArgs) {
if (!OldDecl->getQualifierLoc())
  return false;

assert((NewDecl->getFriendObjectKind() ||((void)0)
        !OldDecl->getLexicalDeclContext()->isDependentContext()) &&((void)0)
       "non-friend with qualified name defined in dependent context")((void)0);
Sema::ContextRAII SavedContext(
    SemaRef,
    const_cast<DeclContext *>(NewDecl->getFriendObjectKind()
                                  ? NewDecl->getLexicalDeclContext()
                                  : OldDecl->getLexicalDeclContext()));

NestedNameSpecifierLoc NewQualifierLoc
    = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),
                                          TemplateArgs);

if (!NewQualifierLoc)
  return true;

NewDecl->setQualifierInfo(NewQualifierLoc);
return false;
70}

72bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,
                                            DeclaratorDecl *NewDecl) {
return ::SubstQualifier(SemaRef, OldDecl, NewDecl, TemplateArgs);
75}

77bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,
                                            TagDecl *NewDecl) {
return ::SubstQualifier(SemaRef, OldDecl, NewDecl, TemplateArgs);
80}

82// Include attribute instantiation code.
83#include "clang/Sema/AttrTemplateInstantiate.inc"

85static void instantiateDependentAlignedAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AlignedAttr *Aligned, Decl *New, bool IsPackExpansion) {
if (Aligned->isAlignmentExpr()) {
  // The alignment expression is a constant expression.
  EnterExpressionEvaluationContext Unevaluated(
      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  ExprResult Result = S.SubstExpr(Aligned->getAlignmentExpr(), TemplateArgs);
  if (!Result.isInvalid())
    S.AddAlignedAttr(New, *Aligned, Result.getAs<Expr>(), IsPackExpansion);
} else {
  TypeSourceInfo *Result = S.SubstType(Aligned->getAlignmentType(),
                                       TemplateArgs, Aligned->getLocation(),
                                       DeclarationName());
  if (Result)
    S.AddAlignedAttr(New, *Aligned, Result, IsPackExpansion);
}
102}

104static void instantiateDependentAlignedAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AlignedAttr *Aligned, Decl *New) {
if (!Aligned->isPackExpansion()) {
  instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
  return;
}

SmallVector<UnexpandedParameterPack, 2> Unexpanded;
if (Aligned->isAlignmentExpr())
  S.collectUnexpandedParameterPacks(Aligned->getAlignmentExpr(),
                                    Unexpanded);
else
  S.collectUnexpandedParameterPacks(Aligned->getAlignmentType()->getTypeLoc(),
                                    Unexpanded);
assert(!Unexpanded.empty() && "Pack expansion without parameter packs?")((void)0);

// Determine whether we can expand this attribute pack yet.
bool Expand = true, RetainExpansion = false;
Optional<unsigned> NumExpansions;
// FIXME: Use the actual location of the ellipsis.
SourceLocation EllipsisLoc = Aligned->getLocation();
if (S.CheckParameterPacksForExpansion(EllipsisLoc, Aligned->getRange(),
                                      Unexpanded, TemplateArgs, Expand,
                                      RetainExpansion, NumExpansions))
  return;

if (!Expand) {
  Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, -1);
  instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, true);
} else {
  for (unsigned I = 0; I != *NumExpansions; ++I) {
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, I);
    instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);
  }
}
140}

142static void instantiateDependentAssumeAlignedAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AssumeAlignedAttr *Aligned, Decl *New) {
// The alignment expression is a constant expression.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

Expr *E, *OE = nullptr;
ExprResult Result = S.SubstExpr(Aligned->getAlignment(), TemplateArgs);
if (Result.isInvalid())
  return;
E = Result.getAs<Expr>();

if (Aligned->getOffset()) {
  Result = S.SubstExpr(Aligned->getOffset(), TemplateArgs);
  if (Result.isInvalid())
    return;
  OE = Result.getAs<Expr>();
}

S.AddAssumeAlignedAttr(New, *Aligned, E, OE);
163}

165static void instantiateDependentAlignValueAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AlignValueAttr *Aligned, Decl *New) {
// The alignment expression is a constant expression.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
ExprResult Result = S.SubstExpr(Aligned->getAlignment(), TemplateArgs);
if (!Result.isInvalid())
  S.AddAlignValueAttr(New, *Aligned, Result.getAs<Expr>());
174}

176static void instantiateDependentAllocAlignAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AllocAlignAttr *Align, Decl *New) {
Expr *Param = IntegerLiteral::Create(
    S.getASTContext(),
    llvm::APInt(64, Align->getParamIndex().getSourceIndex()),
    S.getASTContext().UnsignedLongLongTy, Align->getLocation());
S.AddAllocAlignAttr(New, *Align, Param);
184}

186static void instantiateDependentAnnotationAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AnnotateAttr *Attr, Decl *New) {
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
SmallVector<Expr *, 4> Args;
Args.reserve(Attr->args_size());
for (auto *E : Attr->args()) {
  ExprResult Result = S.SubstExpr(E, TemplateArgs);
  if (!Result.isUsable())
    return;
  Args.push_back(Result.get());
}
S.AddAnnotationAttr(New, *Attr, Attr->getAnnotation(), Args);
200}

202static Expr *instantiateDependentFunctionAttrCondition(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const Attr *A, Expr *OldCond, const Decl *Tmpl, FunctionDecl *New) {
Expr *Cond = nullptr;
{
  Sema::ContextRAII SwitchContext(S, New);
  EnterExpressionEvaluationContext Unevaluated(
      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  ExprResult Result = S.SubstExpr(OldCond, TemplateArgs);
  if (Result.isInvalid())
    return nullptr;
  Cond = Result.getAs<Expr>();
}
if (!Cond->isTypeDependent()) {
  ExprResult Converted = S.PerformContextuallyConvertToBool(Cond);
  if (Converted.isInvalid())
    return nullptr;
  Cond = Converted.get();
}

SmallVector<PartialDiagnosticAt, 8> Diags;
if (OldCond->isValueDependent() && !Cond->isValueDependent() &&
    !Expr::isPotentialConstantExprUnevaluated(Cond, New, Diags)) {
  S.Diag(A->getLocation(), diag::err_attr_cond_never_constant_expr) << A;
  for (const auto &P : Diags)
    S.Diag(P.first, P.second);
  return nullptr;
}
return Cond;
231}

233static void instantiateDependentEnableIfAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const EnableIfAttr *EIA, const Decl *Tmpl, FunctionDecl *New) {
Expr *Cond = instantiateDependentFunctionAttrCondition(
    S, TemplateArgs, EIA, EIA->getCond(), Tmpl, New);

if (Cond)
  New->addAttr(new (S.getASTContext()) EnableIfAttr(S.getASTContext(), *EIA,
                                                    Cond, EIA->getMessage()));
242}

244static void instantiateDependentDiagnoseIfAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const DiagnoseIfAttr *DIA, const Decl *Tmpl, FunctionDecl *New) {
Expr *Cond = instantiateDependentFunctionAttrCondition(
    S, TemplateArgs, DIA, DIA->getCond(), Tmpl, New);

if (Cond)
  New->addAttr(new (S.getASTContext()) DiagnoseIfAttr(
      S.getASTContext(), *DIA, Cond, DIA->getMessage(),
      DIA->getDiagnosticType(), DIA->getArgDependent(), New));
254}

256// Constructs and adds to New a new instance of CUDALaunchBoundsAttr using
257// template A as the base and arguments from TemplateArgs.
258static void instantiateDependentCUDALaunchBoundsAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const CUDALaunchBoundsAttr &Attr, Decl *New) {
// The alignment expression is a constant expression.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

ExprResult Result = S.SubstExpr(Attr.getMaxThreads(), TemplateArgs);
if (Result.isInvalid())
  return;
Expr *MaxThreads = Result.getAs<Expr>();

Expr *MinBlocks = nullptr;
if (Attr.getMinBlocks()) {
  Result = S.SubstExpr(Attr.getMinBlocks(), TemplateArgs);
  if (Result.isInvalid())
    return;
  MinBlocks = Result.getAs<Expr>();
}

S.AddLaunchBoundsAttr(New, Attr, MaxThreads, MinBlocks);
279}

281static void
282instantiateDependentModeAttr(Sema &S,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                           const ModeAttr &Attr, Decl *New) {
S.AddModeAttr(New, Attr, Attr.getMode(),
              /*InInstantiation=*/true);
287}

289/// Instantiation of 'declare simd' attribute and its arguments.
290static void instantiateOMPDeclareSimdDeclAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const OMPDeclareSimdDeclAttr &Attr, Decl *New) {
// Allow 'this' in clauses with varlists.
if (auto *FTD = dyn_cast<FunctionTemplateDecl>(New))
  New = FTD->getTemplatedDecl();
auto *FD = cast<FunctionDecl>(New);
auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(FD->getDeclContext());
SmallVector<Expr *, 4> Uniforms, Aligneds, Alignments, Linears, Steps;
SmallVector<unsigned, 4> LinModifiers;

auto SubstExpr = [&](Expr *E) -> ExprResult {
  if (auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
    if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
      Sema::ContextRAII SavedContext(S, FD);
      LocalInstantiationScope Local(S);
      if (FD->getNumParams() > PVD->getFunctionScopeIndex())
        Local.InstantiatedLocal(
            PVD, FD->getParamDecl(PVD->getFunctionScopeIndex()));
      return S.SubstExpr(E, TemplateArgs);
    }
  Sema::CXXThisScopeRAII ThisScope(S, ThisContext, Qualifiers(),
                                   FD->isCXXInstanceMember());
  return S.SubstExpr(E, TemplateArgs);
};

// Substitute a single OpenMP clause, which is a potentially-evaluated
// full-expression.
auto Subst = [&](Expr *E) -> ExprResult {
  EnterExpressionEvaluationContext Evaluated(
      S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
  ExprResult Res = SubstExpr(E);
  if (Res.isInvalid())
    return Res;
  return S.ActOnFinishFullExpr(Res.get(), false);
};

ExprResult Simdlen;
if (auto *E = Attr.getSimdlen())
  Simdlen = Subst(E);

if (Attr.uniforms_size() > 0) {
  for(auto *E : Attr.uniforms()) {
    ExprResult Inst = Subst(E);
    if (Inst.isInvalid())
      continue;
    Uniforms.push_back(Inst.get());
  }
}

auto AI = Attr.alignments_begin();
for (auto *E : Attr.aligneds()) {
  ExprResult Inst = Subst(E);
  if (Inst.isInvalid())
    continue;
  Aligneds.push_back(Inst.get());
  Inst = ExprEmpty();
  if (*AI)
    Inst = S.SubstExpr(*AI, TemplateArgs);
  Alignments.push_back(Inst.get());
  ++AI;
}

auto SI = Attr.steps_begin();
for (auto *E : Attr.linears()) {
  ExprResult Inst = Subst(E);
  if (Inst.isInvalid())
    continue;
  Linears.push_back(Inst.get());
  Inst = ExprEmpty();
  if (*SI)
    Inst = S.SubstExpr(*SI, TemplateArgs);
  Steps.push_back(Inst.get());
  ++SI;
}
LinModifiers.append(Attr.modifiers_begin(), Attr.modifiers_end());
(void)S.ActOnOpenMPDeclareSimdDirective(
    S.ConvertDeclToDeclGroup(New), Attr.getBranchState(), Simdlen.get(),
    Uniforms, Aligneds, Alignments, Linears, LinModifiers, Steps,
    Attr.getRange());
370}

372/// Instantiation of 'declare variant' attribute and its arguments.
373static void instantiateOMPDeclareVariantAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const OMPDeclareVariantAttr &Attr, Decl *New) {
// Allow 'this' in clauses with varlists.
if (auto *FTD = dyn_cast<FunctionTemplateDecl>(New))
  New = FTD->getTemplatedDecl();
auto *FD = cast<FunctionDecl>(New);
auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(FD->getDeclContext());

auto &&SubstExpr = [FD, ThisContext, &S, &TemplateArgs](Expr *E) {
  if (auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
    if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
      Sema::ContextRAII SavedContext(S, FD);
      LocalInstantiationScope Local(S);
      if (FD->getNumParams() > PVD->getFunctionScopeIndex())
        Local.InstantiatedLocal(
            PVD, FD->getParamDecl(PVD->getFunctionScopeIndex()));
      return S.SubstExpr(E, TemplateArgs);
    }
  Sema::CXXThisScopeRAII ThisScope(S, ThisContext, Qualifiers(),
                                   FD->isCXXInstanceMember());
  return S.SubstExpr(E, TemplateArgs);
};

// Substitute a single OpenMP clause, which is a potentially-evaluated
// full-expression.
auto &&Subst = [&SubstExpr, &S](Expr *E) {
  EnterExpressionEvaluationContext Evaluated(
      S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
  ExprResult Res = SubstExpr(E);
  if (Res.isInvalid())
    return Res;
  return S.ActOnFinishFullExpr(Res.get(), false);
};

ExprResult VariantFuncRef;
if (Expr *E = Attr.getVariantFuncRef()) {
  // Do not mark function as is used to prevent its emission if this is the
  // only place where it is used.
  EnterExpressionEvaluationContext Unevaluated(
      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  VariantFuncRef = Subst(E);
}

// Copy the template version of the OMPTraitInfo and run substitute on all
// score and condition expressiosn.
OMPTraitInfo &TI = S.getASTContext().getNewOMPTraitInfo();
TI = *Attr.getTraitInfos();

// Try to substitute template parameters in score and condition expressions.
auto SubstScoreOrConditionExpr = [&S, Subst](Expr *&E, bool) {
  if (E) {
    EnterExpressionEvaluationContext Unevaluated(
        S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
    ExprResult ER = Subst(E);
    if (ER.isUsable())
      E = ER.get();
    else
      return true;
  }
  return false;
};
if (TI.anyScoreOrCondition(SubstScoreOrConditionExpr))
  return;

Expr *E = VariantFuncRef.get();
// Check function/variant ref for `omp declare variant` but not for `omp
// begin declare variant` (which use implicit attributes).
Optional<std::pair<FunctionDecl *, Expr *>> DeclVarData =
    S.checkOpenMPDeclareVariantFunction(S.ConvertDeclToDeclGroup(New),
                                        VariantFuncRef.get(), TI,
                                        Attr.getRange());

if (!DeclVarData)
  return;

E = DeclVarData.getValue().second;
FD = DeclVarData.getValue().first;

if (auto *VariantDRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) {
  if (auto *VariantFD = dyn_cast<FunctionDecl>(VariantDRE->getDecl())) {
    if (auto *VariantFTD = VariantFD->getDescribedFunctionTemplate()) {
      if (!VariantFTD->isThisDeclarationADefinition())
        return;
      Sema::TentativeAnalysisScope Trap(S);
      const TemplateArgumentList *TAL = TemplateArgumentList::CreateCopy(
          S.Context, TemplateArgs.getInnermost());

      auto *SubstFD = S.InstantiateFunctionDeclaration(VariantFTD, TAL,
                                                       New->getLocation());
      if (!SubstFD)
        return;
      QualType NewType = S.Context.mergeFunctionTypes(
          SubstFD->getType(), FD->getType(),
          /* OfBlockPointer */ false,
          /* Unqualified */ false, /* AllowCXX */ true);
      if (NewType.isNull())
        return;
      S.InstantiateFunctionDefinition(
          New->getLocation(), SubstFD, /* Recursive */ true,
          /* DefinitionRequired */ false, /* AtEndOfTU */ false);
      SubstFD->setInstantiationIsPending(!SubstFD->isDefined());
      E = DeclRefExpr::Create(S.Context, NestedNameSpecifierLoc(),
                              SourceLocation(), SubstFD,
                              /* RefersToEnclosingVariableOrCapture */ false,
                              /* NameLoc */ SubstFD->getLocation(),
                              SubstFD->getType(), ExprValueKind::VK_PRValue);
    }
  }
}

S.ActOnOpenMPDeclareVariantDirective(FD, E, TI, Attr.getRange());
485}

487static void instantiateDependentAMDGPUFlatWorkGroupSizeAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AMDGPUFlatWorkGroupSizeAttr &Attr, Decl *New) {
// Both min and max expression are constant expressions.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

ExprResult Result = S.SubstExpr(Attr.getMin(), TemplateArgs);
if (Result.isInvalid())
  return;
Expr *MinExpr = Result.getAs<Expr>();

Result = S.SubstExpr(Attr.getMax(), TemplateArgs);
if (Result.isInvalid())
  return;
Expr *MaxExpr = Result.getAs<Expr>();

S.addAMDGPUFlatWorkGroupSizeAttr(New, Attr, MinExpr, MaxExpr);
505}

507static ExplicitSpecifier
508instantiateExplicitSpecifier(Sema &S,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                           ExplicitSpecifier ES, FunctionDecl *New) {
if (!ES.getExpr())
  return ES;
Expr *OldCond = ES.getExpr();
Expr *Cond = nullptr;
{
  EnterExpressionEvaluationContext Unevaluated(
      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  ExprResult SubstResult = S.SubstExpr(OldCond, TemplateArgs);
  if (SubstResult.isInvalid()) {
    return ExplicitSpecifier::Invalid();
  }
  Cond = SubstResult.get();
}
ExplicitSpecifier Result(Cond, ES.getKind());
if (!Cond->isTypeDependent())
  S.tryResolveExplicitSpecifier(Result);
return Result;
528}

530static void instantiateDependentAMDGPUWavesPerEUAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const AMDGPUWavesPerEUAttr &Attr, Decl *New) {
// Both min and max expression are constant expressions.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

ExprResult Result = S.SubstExpr(Attr.getMin(), TemplateArgs);
if (Result.isInvalid())
  return;
Expr *MinExpr = Result.getAs<Expr>();

Expr *MaxExpr = nullptr;
if (auto Max = Attr.getMax()) {
  Result = S.SubstExpr(Max, TemplateArgs);
  if (Result.isInvalid())
    return;
  MaxExpr = Result.getAs<Expr>();
}

S.addAMDGPUWavesPerEUAttr(New, Attr, MinExpr, MaxExpr);
551}

553// This doesn't take any template parameters, but we have a custom action that
554// needs to happen when the kernel itself is instantiated. We need to run the
555// ItaniumMangler to mark the names required to name this kernel.
556static void instantiateDependentSYCLKernelAttr(
  Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
  const SYCLKernelAttr &Attr, Decl *New) {
// Functions cannot be partially specialized, so if we are being instantiated,
// we are obviously a complete specialization. Since this attribute is only
// valid on function template declarations, we know that this is a full
// instantiation of a kernel.
S.AddSYCLKernelLambda(cast<FunctionDecl>(New));

// Evaluate whether this would change any of the already evaluated
// __builtin_sycl_unique_stable_name values.
for (auto &Itr : S.Context.SYCLUniqueStableNameEvaluatedValues) {
  const std::string &CurName = Itr.first->ComputeName(S.Context);
  if (Itr.second != CurName) {
    S.Diag(New->getLocation(),
           diag::err_kernel_invalidates_sycl_unique_stable_name);
    S.Diag(Itr.first->getLocation(),
           diag::note_sycl_unique_stable_name_evaluated_here);
    // Update this so future diagnostics work correctly.
    Itr.second = CurName;
  }
}

New->addAttr(Attr.clone(S.getASTContext()));
580}

582/// Determine whether the attribute A might be relevent to the declaration D.
583/// If not, we can skip instantiating it. The attribute may or may not have
584/// been instantiated yet.
585static bool isRelevantAttr(Sema &S, const Decl *D, const Attr *A) {
// 'preferred_name' is only relevant to the matching specialization of the
// template.
if (const auto *PNA = dyn_cast<PreferredNameAttr>(A)) {
  QualType T = PNA->getTypedefType();
  const auto *RD = cast<CXXRecordDecl>(D);
  if (!T->isDependentType() && !RD->isDependentContext() &&
      !declaresSameEntity(T->getAsCXXRecordDecl(), RD))
    return false;
  for (const auto *ExistingPNA : D->specific_attrs<PreferredNameAttr>())
    if (S.Context.hasSameType(ExistingPNA->getTypedefType(),
                              PNA->getTypedefType()))
      return false;
  return true;
}

return true;
602}

604void Sema::InstantiateAttrsForDecl(
  const MultiLevelTemplateArgumentList &TemplateArgs, const Decl *Tmpl,
  Decl *New, LateInstantiatedAttrVec *LateAttrs,
  LocalInstantiationScope *OuterMostScope) {
if (NamedDecl *ND = dyn_cast<NamedDecl>(New)) {
  // FIXME: This function is called multiple times for the same template
  // specialization. We should only instantiate attributes that were added
  // since the previous instantiation.
  for (const auto *TmplAttr : Tmpl->attrs()) {
    if (!isRelevantAttr(*this, New, TmplAttr))
      continue;

    // FIXME: If any of the special case versions from InstantiateAttrs become
    // applicable to template declaration, we'll need to add them here.
    CXXThisScopeRAII ThisScope(
        *this, dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext()),
        Qualifiers(), ND->isCXXInstanceMember());

    Attr *NewAttr = sema::instantiateTemplateAttributeForDecl(
        TmplAttr, Context, *this, TemplateArgs);
    if (NewAttr && isRelevantAttr(*this, New, NewAttr))
      New->addAttr(NewAttr);
  }
}
628}

630static Sema::RetainOwnershipKind
631attrToRetainOwnershipKind(const Attr *A) {
switch (A->getKind()) {
case clang::attr::CFConsumed:
  return Sema::RetainOwnershipKind::CF;
case clang::attr::OSConsumed:
  return Sema::RetainOwnershipKind::OS;
case clang::attr::NSConsumed:
  return Sema::RetainOwnershipKind::NS;
default:
  llvm_unreachable("Wrong argument supplied")__builtin_unreachable();
}
642}

644void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                          const Decl *Tmpl, Decl *New,
                          LateInstantiatedAttrVec *LateAttrs,
                          LocalInstantiationScope *OuterMostScope) {
for (const auto *TmplAttr : Tmpl->attrs()) {
  if (!isRelevantAttr(*this, New, TmplAttr))
    continue;

  // FIXME: This should be generalized to more than just the AlignedAttr.
  const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr);
  if (Aligned && Aligned->isAlignmentDependent()) {
    instantiateDependentAlignedAttr(*this, TemplateArgs, Aligned, New);
    continue;
  }

  if (const auto *AssumeAligned = dyn_cast<AssumeAlignedAttr>(TmplAttr)) {
    instantiateDependentAssumeAlignedAttr(*this, TemplateArgs, AssumeAligned, New);
    continue;
  }

  if (const auto *AlignValue = dyn_cast<AlignValueAttr>(TmplAttr)) {
    instantiateDependentAlignValueAttr(*this, TemplateArgs, AlignValue, New);
    continue;
  }

  if (const auto *AllocAlign = dyn_cast<AllocAlignAttr>(TmplAttr)) {
    instantiateDependentAllocAlignAttr(*this, TemplateArgs, AllocAlign, New);
    continue;
  }

  if (const auto *Annotate = dyn_cast<AnnotateAttr>(TmplAttr)) {
    instantiateDependentAnnotationAttr(*this, TemplateArgs, Annotate, New);
    continue;
  }

  if (const auto *EnableIf = dyn_cast<EnableIfAttr>(TmplAttr)) {
    instantiateDependentEnableIfAttr(*this, TemplateArgs, EnableIf, Tmpl,
                                     cast<FunctionDecl>(New));
    continue;
  }

  if (const auto *DiagnoseIf = dyn_cast<DiagnoseIfAttr>(TmplAttr)) {
    instantiateDependentDiagnoseIfAttr(*this, TemplateArgs, DiagnoseIf, Tmpl,
                                       cast<FunctionDecl>(New));
    continue;
  }

  if (const auto *CUDALaunchBounds =
          dyn_cast<CUDALaunchBoundsAttr>(TmplAttr)) {
    instantiateDependentCUDALaunchBoundsAttr(*this, TemplateArgs,
                                             *CUDALaunchBounds, New);
    continue;
  }

  if (const auto *Mode = dyn_cast<ModeAttr>(TmplAttr)) {
    instantiateDependentModeAttr(*this, TemplateArgs, *Mode, New);
    continue;
  }

  if (const auto *OMPAttr = dyn_cast<OMPDeclareSimdDeclAttr>(TmplAttr)) {
    instantiateOMPDeclareSimdDeclAttr(*this, TemplateArgs, *OMPAttr, New);
    continue;
  }

  if (const auto *OMPAttr = dyn_cast<OMPDeclareVariantAttr>(TmplAttr)) {
    instantiateOMPDeclareVariantAttr(*this, TemplateArgs, *OMPAttr, New);
    continue;
  }

  if (const auto *AMDGPUFlatWorkGroupSize =
          dyn_cast<AMDGPUFlatWorkGroupSizeAttr>(TmplAttr)) {
    instantiateDependentAMDGPUFlatWorkGroupSizeAttr(
        *this, TemplateArgs, *AMDGPUFlatWorkGroupSize, New);
  }

  if (const auto *AMDGPUFlatWorkGroupSize =
          dyn_cast<AMDGPUWavesPerEUAttr>(TmplAttr)) {
    instantiateDependentAMDGPUWavesPerEUAttr(*this, TemplateArgs,
                                             *AMDGPUFlatWorkGroupSize, New);
  }

  // Existing DLL attribute on the instantiation takes precedence.
  if (TmplAttr->getKind() == attr::DLLExport ||
      TmplAttr->getKind() == attr::DLLImport) {
    if (New->hasAttr<DLLExportAttr>() || New->hasAttr<DLLImportAttr>()) {
      continue;
    }
  }

  if (const auto *ABIAttr = dyn_cast<ParameterABIAttr>(TmplAttr)) {
    AddParameterABIAttr(New, *ABIAttr, ABIAttr->getABI());
    continue;
  }

  if (isa<NSConsumedAttr>(TmplAttr) || isa<OSConsumedAttr>(TmplAttr) ||
      isa<CFConsumedAttr>(TmplAttr)) {
    AddXConsumedAttr(New, *TmplAttr, attrToRetainOwnershipKind(TmplAttr),
                     /*template instantiation=*/true);
    continue;
  }

  if (auto *A = dyn_cast<PointerAttr>(TmplAttr)) {
    if (!New->hasAttr<PointerAttr>())
      New->addAttr(A->clone(Context));
    continue;
  }

  if (auto *A = dyn_cast<OwnerAttr>(TmplAttr)) {
    if (!New->hasAttr<OwnerAttr>())
      New->addAttr(A->clone(Context));
    continue;
  }

  if (auto *A = dyn_cast<SYCLKernelAttr>(TmplAttr)) {
    instantiateDependentSYCLKernelAttr(*this, TemplateArgs, *A, New);
    continue;
  }

  assert(!TmplAttr->isPackExpansion())((void)0);
  if (TmplAttr->isLateParsed() && LateAttrs) {
    // Late parsed attributes must be instantiated and attached after the
    // enclosing class has been instantiated.  See Sema::InstantiateClass.
    LocalInstantiationScope *Saved = nullptr;
    if (CurrentInstantiationScope)
      Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);
    LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));
  } else {
    // Allow 'this' within late-parsed attributes.
    auto *ND = cast<NamedDecl>(New);
    auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext());
    CXXThisScopeRAII ThisScope(*this, ThisContext, Qualifiers(),
                               ND->isCXXInstanceMember());

    Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
                                                       *this, TemplateArgs);
    if (NewAttr && isRelevantAttr(*this, New, TmplAttr))
      New->addAttr(NewAttr);
  }
}
783}

785/// In the MS ABI, we need to instantiate default arguments of dllexported
786/// default constructors along with the constructor definition. This allows IR
787/// gen to emit a constructor closure which calls the default constructor with
788/// its default arguments.
789void Sema::InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor) {
assert(Context.getTargetInfo().getCXXABI().isMicrosoft() &&((void)0)
       Ctor->isDefaultConstructor())((void)0);
unsigned NumParams = Ctor->getNumParams();
if (NumParams == 0)
  return;
DLLExportAttr *Attr = Ctor->getAttr<DLLExportAttr>();
if (!Attr)
  return;
for (unsigned I = 0; I != NumParams; ++I) {
  (void)CheckCXXDefaultArgExpr(Attr->getLocation(), Ctor,
                                 Ctor->getParamDecl(I));
  DiscardCleanupsInEvaluationContext();
}
803}

805/// Get the previous declaration of a declaration for the purposes of template
806/// instantiation. If this finds a previous declaration, then the previous
807/// declaration of the instantiation of D should be an instantiation of the
808/// result of this function.
809template<typename DeclT>
810static DeclT *getPreviousDeclForInstantiation(DeclT *D) {
DeclT *Result = D->getPreviousDecl();

// If the declaration is within a class, and the previous declaration was
// merged from a different definition of that class, then we don't have a
// previous declaration for the purpose of template instantiation.
if (Result && isa<CXXRecordDecl>(D->getDeclContext()) &&
    D->getLexicalDeclContext() != Result->getLexicalDeclContext())
  return nullptr;

return Result;
821}

823Decl *
824TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
llvm_unreachable("Translation units cannot be instantiated")__builtin_unreachable();
826}

828Decl *
829TemplateDeclInstantiator::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
llvm_unreachable("pragma comment cannot be instantiated")__builtin_unreachable();
831}

833Decl *TemplateDeclInstantiator::VisitPragmaDetectMismatchDecl(
  PragmaDetectMismatchDecl *D) {
llvm_unreachable("pragma comment cannot be instantiated")__builtin_unreachable();
836}

838Decl *
839TemplateDeclInstantiator::VisitExternCContextDecl(ExternCContextDecl *D) {
llvm_unreachable("extern \"C\" context cannot be instantiated")__builtin_unreachable();
841}

843Decl *TemplateDeclInstantiator::VisitMSGuidDecl(MSGuidDecl *D) {
llvm_unreachable("GUID declaration cannot be instantiated")__builtin_unreachable();
845}

847Decl *TemplateDeclInstantiator::VisitTemplateParamObjectDecl(
  TemplateParamObjectDecl *D) {
llvm_unreachable("template parameter objects cannot be instantiated")__builtin_unreachable();
850}

852Decl *
853TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {
LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),
                                    D->getIdentifier());
Owner->addDecl(Inst);
return Inst;
858}

860Decl *
861TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {
llvm_unreachable("Namespaces cannot be instantiated")__builtin_unreachable();
863}

865Decl *
866TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
NamespaceAliasDecl *Inst
  = NamespaceAliasDecl::Create(SemaRef.Context, Owner,
                               D->getNamespaceLoc(),
                               D->getAliasLoc(),
                               D->getIdentifier(),
                               D->getQualifierLoc(),
                               D->getTargetNameLoc(),
                               D->getNamespace());
Owner->addDecl(Inst);
return Inst;
877}

879Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
                                                         bool IsTypeAlias) {
bool Invalid = false;
TypeSourceInfo *DI = D->getTypeSourceInfo();
if (DI->getType()->isInstantiationDependentType() ||
    DI->getType()->isVariablyModifiedType()) {
  DI = SemaRef.SubstType(DI, TemplateArgs,
                         D->getLocation(), D->getDeclName());
  if (!DI) {
    Invalid = true;
    DI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);
  }
} else {
  SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
}

// HACK: 2012-10-23 g++ has a bug where it gets the value kind of ?: wrong.
// libstdc++ relies upon this bug in its implementation of common_type.  If we
// happen to be processing that implementation, fake up the g++ ?:
// semantics. See LWG issue 2141 for more information on the bug.  The bugs
// are fixed in g++ and libstdc++ 4.9.0 (2014-04-22).
const DecltypeType *DT = DI->getType()->getAs<DecltypeType>();
CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
if (DT && RD && isa<ConditionalOperator>(DT->getUnderlyingExpr()) &&
    DT->isReferenceType() &&
    RD->getEnclosingNamespaceContext() == SemaRef.getStdNamespace() &&
    RD->getIdentifier() && RD->getIdentifier()->isStr("common_type") &&
    D->getIdentifier() && D->getIdentifier()->isStr("type") &&
    SemaRef.getSourceManager().isInSystemHeader(D->getBeginLoc()))
  // Fold it to the (non-reference) type which g++ would have produced.
  DI = SemaRef.Context.getTrivialTypeSourceInfo(
    DI->getType().getNonReferenceType());

// Create the new typedef
TypedefNameDecl *Typedef;
if (IsTypeAlias)
  Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),
                                  D->getLocation(), D->getIdentifier(), DI);
else
  Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),
                                D->getLocation(), D->getIdentifier(), DI);
if (Invalid)
  Typedef->setInvalidDecl();

// If the old typedef was the name for linkage purposes of an anonymous
// tag decl, re-establish that relationship for the new typedef.
if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {
  TagDecl *oldTag = oldTagType->getDecl();
  if (oldTag->getTypedefNameForAnonDecl() == D && !Invalid) {
    TagDecl *newTag = DI->getType()->castAs<TagType>()->getDecl();
    assert(!newTag->hasNameForLinkage())((void)0);
    newTag->setTypedefNameForAnonDecl(Typedef);
  }
}

if (TypedefNameDecl *Prev = getPreviousDeclForInstantiation(D)) {
  NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,
                                                     TemplateArgs);
  if (!InstPrev)
    return nullptr;

  TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);

  // If the typedef types are not identical, reject them.
  SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);

  Typedef->setPreviousDecl(InstPrevTypedef);
}

SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);

if (D->getUnderlyingType()->getAs<DependentNameType>())
  SemaRef.inferGslPointerAttribute(Typedef);

Typedef->setAccess(D->getAccess());

return Typedef;
956}

958Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);
if (Typedef)
  Owner->addDecl(Typedef);
return Typedef;
963}

965Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {
Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);
if (Typedef)
  Owner->addDecl(Typedef);
return Typedef;
970}

972Decl *
973TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
// Create a local instantiation scope for this type alias template, which
// will contain the instantiations of the template parameters.
LocalInstantiationScope Scope(SemaRef);

TemplateParameterList *TempParams = D->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

TypeAliasDecl *Pattern = D->getTemplatedDecl();

TypeAliasTemplateDecl *PrevAliasTemplate = nullptr;
if (getPreviousDeclForInstantiation<TypedefNameDecl>(Pattern)) {
  DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
  if (!Found.empty()) {
    PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(Found.front());
  }
}

TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(
  InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));
if (!AliasInst)
  return nullptr;

TypeAliasTemplateDecl *Inst
  = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),
                                  D->getDeclName(), InstParams, AliasInst);
AliasInst->setDescribedAliasTemplate(Inst);
if (PrevAliasTemplate)
  Inst->setPreviousDecl(PrevAliasTemplate);

Inst->setAccess(D->getAccess());

if (!PrevAliasTemplate)
  Inst->setInstantiatedFromMemberTemplate(D);

Owner->addDecl(Inst);

return Inst;
1013}

1015Decl *TemplateDeclInstantiator::VisitBindingDecl(BindingDecl *D) {
auto *NewBD = BindingDecl::Create(SemaRef.Context, Owner, D->getLocation(),
                                  D->getIdentifier());
NewBD->setReferenced(D->isReferenced());
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewBD);
return NewBD;
1021}

1023Decl *TemplateDeclInstantiator::VisitDecompositionDecl(DecompositionDecl *D) {
// Transform the bindings first.
SmallVector<BindingDecl*, 16> NewBindings;
for (auto *OldBD : D->bindings())
  NewBindings.push_back(cast<BindingDecl>(VisitBindingDecl(OldBD)));
ArrayRef<BindingDecl*> NewBindingArray = NewBindings;

auto *NewDD = cast_or_null<DecompositionDecl>(
    VisitVarDecl(D, /*InstantiatingVarTemplate=*/false, &NewBindingArray));

if (!NewDD || NewDD->isInvalidDecl())
  for (auto *NewBD : NewBindings)
    NewBD->setInvalidDecl();

return NewDD;
1038}

1040Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
return VisitVarDecl(D, /*InstantiatingVarTemplate=*/false);
1042}

1044Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D,
                                           bool InstantiatingVarTemplate,
                                           ArrayRef<BindingDecl*> *Bindings) {

// Do substitution on the type of the declaration
TypeSourceInfo *DI = SemaRef.SubstType(
    D->getTypeSourceInfo(), TemplateArgs, D->getTypeSpecStartLoc(),
    D->getDeclName(), /*AllowDeducedTST*/true);
if (!DI)
  return nullptr;

if (DI->getType()->isFunctionType()) {
  SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
    << D->isStaticDataMember() << DI->getType();
  return nullptr;
}

DeclContext *DC = Owner;
if (D->isLocalExternDecl())
  SemaRef.adjustContextForLocalExternDecl(DC);

// Build the instantiated declaration.
VarDecl *Var;
if (Bindings)
  Var = DecompositionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
                                  D->getLocation(), DI->getType(), DI,
                                  D->getStorageClass(), *Bindings);
else
  Var = VarDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),
                        D->getLocation(), D->getIdentifier(), DI->getType(),
                        DI, D->getStorageClass());

// In ARC, infer 'retaining' for variables of retainable type.
if (SemaRef.getLangOpts().ObjCAutoRefCount &&
    SemaRef.inferObjCARCLifetime(Var))
  Var->setInvalidDecl();

if (SemaRef.getLangOpts().OpenCL)
  SemaRef.deduceOpenCLAddressSpace(Var);

// Substitute the nested name specifier, if any.
if (SubstQualifier(D, Var))
  return nullptr;

SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,
                                   StartingScope, InstantiatingVarTemplate);
if (D->isNRVOVariable() && !Var->isInvalidDecl()) {
  QualType RT;
  if (auto *F = dyn_cast<FunctionDecl>(DC))
    RT = F->getReturnType();
  else if (isa<BlockDecl>(DC))
    RT = cast<FunctionType>(SemaRef.getCurBlock()->FunctionType)
             ->getReturnType();
  else
    llvm_unreachable("Unknown context type")__builtin_unreachable();

  // This is the last chance we have of checking copy elision eligibility
  // for functions in dependent contexts. The sema actions for building
  // the return statement during template instantiation will have no effect
  // regarding copy elision, since NRVO propagation runs on the scope exit
  // actions, and these are not run on instantiation.
  // This might run through some VarDecls which were returned from non-taken
  // 'if constexpr' branches, and these will end up being constructed on the
  // return slot even if they will never be returned, as a sort of accidental
  // 'optimization'. Notably, functions with 'auto' return types won't have it
  // deduced by this point. Coupled with the limitation described
  // previously, this makes it very hard to support copy elision for these.
  Sema::NamedReturnInfo Info = SemaRef.getNamedReturnInfo(Var);
  bool NRVO = SemaRef.getCopyElisionCandidate(Info, RT) != nullptr;
  Var->setNRVOVariable(NRVO);
}

Var->setImplicit(D->isImplicit());

if (Var->isStaticLocal())
  SemaRef.CheckStaticLocalForDllExport(Var);

return Var;
1122}

1124Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
AccessSpecDecl* AD
  = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,
                           D->getAccessSpecifierLoc(), D->getColonLoc());
Owner->addHiddenDecl(AD);
return AD;
1130}

1132Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
bool Invalid = false;
TypeSourceInfo *DI = D->getTypeSourceInfo();
if (DI->getType()->isInstantiationDependentType() ||
    DI->getType()->isVariablyModifiedType())  {
  DI = SemaRef.SubstType(DI, TemplateArgs,
                         D->getLocation(), D->getDeclName());
  if (!DI) {
    DI = D->getTypeSourceInfo();
    Invalid = true;
  } else if (DI->getType()->isFunctionType()) {
    // C++ [temp.arg.type]p3:
    //   If a declaration acquires a function type through a type
    //   dependent on a template-parameter and this causes a
    //   declaration that does not use the syntactic form of a
    //   function declarator to have function type, the program is
    //   ill-formed.
    SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
      << DI->getType();
    Invalid = true;
  }
} else {
  SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
}

Expr *BitWidth = D->getBitWidth();
if (Invalid)
  BitWidth = nullptr;
else if (BitWidth) {
  // The bit-width expression is a constant expression.
  EnterExpressionEvaluationContext Unevaluated(
      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

  ExprResult InstantiatedBitWidth
    = SemaRef.SubstExpr(BitWidth, TemplateArgs);
  if (InstantiatedBitWidth.isInvalid()) {
    Invalid = true;
    BitWidth = nullptr;
  } else
    BitWidth = InstantiatedBitWidth.getAs<Expr>();
}

FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(),
                                          DI->getType(), DI,
                                          cast<RecordDecl>(Owner),
                                          D->getLocation(),
                                          D->isMutable(),
                                          BitWidth,
                                          D->getInClassInitStyle(),
                                          D->getInnerLocStart(),
                                          D->getAccess(),
                                          nullptr);
if (!Field) {
  cast<Decl>(Owner)->setInvalidDecl();
  return nullptr;
}

SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);

if (Field->hasAttrs())
  SemaRef.CheckAlignasUnderalignment(Field);

if (Invalid)
  Field->setInvalidDecl();

if (!Field->getDeclName()) {
  // Keep track of where this decl came from.
  SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
}
if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
  if (Parent->isAnonymousStructOrUnion() &&
      Parent->getRedeclContext()->isFunctionOrMethod())
    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
}

Field->setImplicit(D->isImplicit());
Field->setAccess(D->getAccess());
Owner->addDecl(Field);

return Field;
1212}

1214Decl *TemplateDeclInstantiator::VisitMSPropertyDecl(MSPropertyDecl *D) {
bool Invalid = false;
TypeSourceInfo *DI = D->getTypeSourceInfo();

if (DI->getType()->isVariablyModifiedType()) {
  SemaRef.Diag(D->getLocation(), diag::err_property_is_variably_modified)
    << D;
  Invalid = true;
} else if (DI->getType()->isInstantiationDependentType())  {
  DI = SemaRef.SubstType(DI, TemplateArgs,
                         D->getLocation(), D->getDeclName());
  if (!DI) {
    DI = D->getTypeSourceInfo();
    Invalid = true;
  } else if (DI->getType()->isFunctionType()) {
    // C++ [temp.arg.type]p3:
    //   If a declaration acquires a function type through a type
    //   dependent on a template-parameter and this causes a
    //   declaration that does not use the syntactic form of a
    //   function declarator to have function type, the program is
    //   ill-formed.
    SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
    << DI->getType();
    Invalid = true;
  }
} else {
  SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), DI->getType());
}

MSPropertyDecl *Property = MSPropertyDecl::Create(
    SemaRef.Context, Owner, D->getLocation(), D->getDeclName(), DI->getType(),
    DI, D->getBeginLoc(), D->getGetterId(), D->getSetterId());

SemaRef.InstantiateAttrs(TemplateArgs, D, Property, LateAttrs,
                         StartingScope);

if (Invalid)
  Property->setInvalidDecl();

Property->setAccess(D->getAccess());
Owner->addDecl(Property);

return Property;
1257}

1259Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
NamedDecl **NamedChain =
  new (SemaRef.Context)NamedDecl*[D->getChainingSize()];

int i = 0;
for (auto *PI : D->chain()) {
  NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), PI,
                                            TemplateArgs);
  if (!Next)
    return nullptr;

  NamedChain[i++] = Next;
}

QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();
IndirectFieldDecl *IndirectField = IndirectFieldDecl::Create(
    SemaRef.Context, Owner, D->getLocation(), D->getIdentifier(), T,
    {NamedChain, D->getChainingSize()});

for (const auto *Attr : D->attrs())
  IndirectField->addAttr(Attr->clone(SemaRef.Context));

IndirectField->setImplicit(D->isImplicit());
IndirectField->setAccess(D->getAccess());
Owner->addDecl(IndirectField);
return IndirectField;
1285}

1287Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {
// Handle friend type expressions by simply substituting template
// parameters into the pattern type and checking the result.
if (TypeSourceInfo *Ty = D->getFriendType()) {
  TypeSourceInfo *InstTy;
  // If this is an unsupported friend, don't bother substituting template
  // arguments into it. The actual type referred to won't be used by any
  // parts of Clang, and may not be valid for instantiating. Just use the
  // same info for the instantiated friend.
  if (D->isUnsupportedFriend()) {
    InstTy = Ty;
  } else {
    InstTy = SemaRef.SubstType(Ty, TemplateArgs,
                               D->getLocation(), DeclarationName());
  }
  if (!InstTy)
    return nullptr;

  FriendDecl *FD = SemaRef.CheckFriendTypeDecl(D->getBeginLoc(),
                                               D->getFriendLoc(), InstTy);
  if (!FD)
    return nullptr;

  FD->setAccess(AS_public);
  FD->setUnsupportedFriend(D->isUnsupportedFriend());
  Owner->addDecl(FD);
  return FD;
}

NamedDecl *ND = D->getFriendDecl();
assert(ND && "friend decl must be a decl or a type!")((void)0);

// All of the Visit implementations for the various potential friend
// declarations have to be carefully written to work for friend
// objects, with the most important detail being that the target
// decl should almost certainly not be placed in Owner.
Decl *NewND = Visit(ND);
if (!NewND) return nullptr;

FriendDecl *FD =
  FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),
                     cast<NamedDecl>(NewND), D->getFriendLoc());
FD->setAccess(AS_public);
FD->setUnsupportedFriend(D->isUnsupportedFriend());
Owner->addDecl(FD);
return FD;
1333}

1335Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
Expr *AssertExpr = D->getAssertExpr();

// The expression in a static assertion is a constant expression.
EnterExpressionEvaluationContext Unevaluated(
    SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

ExprResult InstantiatedAssertExpr
  = SemaRef.SubstExpr(AssertExpr, TemplateArgs);
if (InstantiatedAssertExpr.isInvalid())
  return nullptr;

return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
                                            InstantiatedAssertExpr.get(),
                                            D->getMessage(),
                                            D->getRParenLoc(),
                                            D->isFailed());
1352}

1354Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
EnumDecl *PrevDecl = nullptr;
if (EnumDecl *PatternPrev = getPreviousDeclForInstantiation(D)) {
  NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
                                                 PatternPrev,
                                                 TemplateArgs);
  if (!Prev) return nullptr;
  PrevDecl = cast<EnumDecl>(Prev);
}

EnumDecl *Enum =
    EnumDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),
                     D->getLocation(), D->getIdentifier(), PrevDecl,
                     D->isScoped(), D->isScopedUsingClassTag(), D->isFixed());
if (D->isFixed()) {
  if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {
    // If we have type source information for the underlying type, it means it
    // has been explicitly set by the user. Perform substitution on it before
    // moving on.
    SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
    TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,
                                              DeclarationName());
    if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))
      Enum->setIntegerType(SemaRef.Context.IntTy);
    else
      Enum->setIntegerTypeSourceInfo(NewTI);
  } else {
    assert(!D->getIntegerType()->isDependentType()((void)0)
           && "Dependent type without type source info")((void)0);
    Enum->setIntegerType(D->getIntegerType());
  }
}

SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);

Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);
Enum->setAccess(D->getAccess());
// Forward the mangling number from the template to the instantiated decl.
SemaRef.Context.setManglingNumber(Enum, SemaRef.Context.getManglingNumber(D));
// See if the old tag was defined along with a declarator.
// If it did, mark the new tag as being associated with that declarator.
if (DeclaratorDecl *DD = SemaRef.Context.getDeclaratorForUnnamedTagDecl(D))
  SemaRef.Context.addDeclaratorForUnnamedTagDecl(Enum, DD);
// See if the old tag was defined along with a typedef.
// If it did, mark the new tag as being associated with that typedef.
if (TypedefNameDecl *TND = SemaRef.Context.getTypedefNameForUnnamedTagDecl(D))
  SemaRef.Context.addTypedefNameForUnnamedTagDecl(Enum, TND);
if (SubstQualifier(D, Enum)) return nullptr;
Owner->addDecl(Enum);

EnumDecl *Def = D->getDefinition();
if (Def && Def != D) {
  // If this is an out-of-line definition of an enum member template, check
  // that the underlying types match in the instantiation of both
  // declarations.
  if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {
    SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
    QualType DefnUnderlying =
      SemaRef.SubstType(TI->getType(), TemplateArgs,
                        UnderlyingLoc, DeclarationName());
    SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
                                   DefnUnderlying, /*IsFixed=*/true, Enum);
  }
}

// C++11 [temp.inst]p1: The implicit instantiation of a class template
// specialization causes the implicit instantiation of the declarations, but
// not the definitions of scoped member enumerations.
//
// DR1484 clarifies that enumeration definitions inside of a template
// declaration aren't considered entities that can be separately instantiated
// from the rest of the entity they are declared inside of.
if (isDeclWithinFunction(D) ? D == Def : Def && !Enum->isScoped()) {
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);
  InstantiateEnumDefinition(Enum, Def);
}

return Enum;
1432}

1434void TemplateDeclInstantiator::InstantiateEnumDefinition(
  EnumDecl *Enum, EnumDecl *Pattern) {
Enum->startDefinition();

// Update the location to refer to the definition.
Enum->setLocation(Pattern->getLocation());

SmallVector<Decl*, 4> Enumerators;

EnumConstantDecl *LastEnumConst = nullptr;
for (auto *EC : Pattern->enumerators()) {
  // The specified value for the enumerator.
  ExprResult Value((Expr *)nullptr);
  if (Expr *UninstValue = EC->getInitExpr()) {
    // The enumerator's value expression is a constant expression.
    EnterExpressionEvaluationContext Unevaluated(
        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

    Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);
  }

  // Drop the initial value and continue.
  bool isInvalid = false;
  if (Value.isInvalid()) {
    Value = nullptr;
    isInvalid = true;
  }

  EnumConstantDecl *EnumConst
    = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
                                EC->getLocation(), EC->getIdentifier(),
                                Value.get());

  if (isInvalid) {
    if (EnumConst)
      EnumConst->setInvalidDecl();
    Enum->setInvalidDecl();
  }

  if (EnumConst) {
    SemaRef.InstantiateAttrs(TemplateArgs, EC, EnumConst);

    EnumConst->setAccess(Enum->getAccess());
    Enum->addDecl(EnumConst);
    Enumerators.push_back(EnumConst);
    LastEnumConst = EnumConst;

    if (Pattern->getDeclContext()->isFunctionOrMethod() &&
        !Enum->isScoped()) {
      // If the enumeration is within a function or method, record the enum
      // constant as a local.
      SemaRef.CurrentInstantiationScope->InstantiatedLocal(EC, EnumConst);
    }
  }
}

SemaRef.ActOnEnumBody(Enum->getLocation(), Enum->getBraceRange(), Enum,
                      Enumerators, nullptr, ParsedAttributesView());
1492}

1494Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {
llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.")__builtin_unreachable();
1496}

1498Decl *
1499TemplateDeclInstantiator::VisitBuiltinTemplateDecl(BuiltinTemplateDecl *D) {
llvm_unreachable("BuiltinTemplateDecls cannot be instantiated.")__builtin_unreachable();
1501}

1503Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);

// Create a local instantiation scope for this class template, which
// will contain the instantiations of the template parameters.
LocalInstantiationScope Scope(SemaRef);
TemplateParameterList *TempParams = D->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

CXXRecordDecl *Pattern = D->getTemplatedDecl();

// Instantiate the qualifier.  We have to do this first in case
// we're a friend declaration, because if we are then we need to put
// the new declaration in the appropriate context.
NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();
if (QualifierLoc) {
  QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
                                                     TemplateArgs);
  if (!QualifierLoc)
    return nullptr;
}

CXXRecordDecl *PrevDecl = nullptr;
ClassTemplateDecl *PrevClassTemplate = nullptr;

if (!isFriend && getPreviousDeclForInstantiation(Pattern)) {
  DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
  if (!Found.empty()) {
    PrevClassTemplate = dyn_cast<ClassTemplateDecl>(Found.front());
    if (PrevClassTemplate)
      PrevDecl = PrevClassTemplate->getTemplatedDecl();
  }
}

// If this isn't a friend, then it's a member template, in which
// case we just want to build the instantiation in the
// specialization.  If it is a friend, we want to build it in
// the appropriate context.
DeclContext *DC = Owner;
if (isFriend) {
  if (QualifierLoc) {
    CXXScopeSpec SS;
    SS.Adopt(QualifierLoc);
    DC = SemaRef.computeDeclContext(SS);
    if (!DC) return nullptr;
  } else {
    DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),
                                         Pattern->getDeclContext(),
                                         TemplateArgs);
  }

  // Look for a previous declaration of the template in the owning
  // context.
  LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),
                 Sema::LookupOrdinaryName,
                 SemaRef.forRedeclarationInCurContext());
  SemaRef.LookupQualifiedName(R, DC);

  if (R.isSingleResult()) {
    PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();
    if (PrevClassTemplate)
      PrevDecl = PrevClassTemplate->getTemplatedDecl();
  }

  if (!PrevClassTemplate && QualifierLoc) {
    SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)
      << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC
      << QualifierLoc.getSourceRange();
    return nullptr;
  }

  if (PrevClassTemplate) {
    TemplateParameterList *PrevParams
      = PrevClassTemplate->getMostRecentDecl()->getTemplateParameters();

    // Make sure the parameter lists match.
    if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams, true,
                                                Sema::TPL_TemplateMatch))
      return nullptr;

    // Do some additional validation, then merge default arguments
    // from the existing declarations.
    if (SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
                                           Sema::TPC_ClassTemplate))
      return nullptr;
  }
}

CXXRecordDecl *RecordInst = CXXRecordDecl::Create(
    SemaRef.Context, Pattern->getTagKind(), DC, Pattern->getBeginLoc(),
    Pattern->getLocation(), Pattern->getIdentifier(), PrevDecl,
    /*DelayTypeCreation=*/true);

if (QualifierLoc)
  RecordInst->setQualifierInfo(QualifierLoc);

SemaRef.InstantiateAttrsForDecl(TemplateArgs, Pattern, RecordInst, LateAttrs,
                                                            StartingScope);

ClassTemplateDecl *Inst
  = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
                              D->getIdentifier(), InstParams, RecordInst);
assert(!(isFriend && Owner->isDependentContext()))((void)0);
Inst->setPreviousDecl(PrevClassTemplate);

RecordInst->setDescribedClassTemplate(Inst);

if (isFriend) {
  if (PrevClassTemplate)
    Inst->setAccess(PrevClassTemplate->getAccess());
  else
    Inst->setAccess(D->getAccess());

  Inst->setObjectOfFriendDecl();
  // TODO: do we want to track the instantiation progeny of this
  // friend target decl?
} else {
  Inst->setAccess(D->getAccess());
  if (!PrevClassTemplate)
    Inst->setInstantiatedFromMemberTemplate(D);
}

// Trigger creation of the type for the instantiation.
SemaRef.Context.getInjectedClassNameType(RecordInst,
                                  Inst->getInjectedClassNameSpecialization());

// Finish handling of friends.
if (isFriend) {
  DC->makeDeclVisibleInContext(Inst);
  Inst->setLexicalDeclContext(Owner);
  RecordInst->setLexicalDeclContext(Owner);
  return Inst;
}

if (D->isOutOfLine()) {
  Inst->setLexicalDeclContext(D->getLexicalDeclContext());
  RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());
}

Owner->addDecl(Inst);

if (!PrevClassTemplate) {
  // Queue up any out-of-line partial specializations of this member
  // class template; the client will force their instantiation once
  // the enclosing class has been instantiated.
  SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
  D->getPartialSpecializations(PartialSpecs);
  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
    if (PartialSpecs[I]->getFirstDecl()->isOutOfLine())
      OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));
}

return Inst;
1658}

1660Decl *
1661TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(
                                 ClassTemplatePartialSpecializationDecl *D) {
ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();

// Lookup the already-instantiated declaration in the instantiation
// of the class template and return that.
DeclContext::lookup_result Found
  = Owner->lookup(ClassTemplate->getDeclName());
if (Found.empty())
  return nullptr;

ClassTemplateDecl *InstClassTemplate
  = dyn_cast<ClassTemplateDecl>(Found.front());
if (!InstClassTemplate)
  return nullptr;

if (ClassTemplatePartialSpecializationDecl *Result
      = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))
  return Result;

return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);
1682}

1684Decl *TemplateDeclInstantiator::VisitVarTemplateDecl(VarTemplateDecl *D) {
assert(D->getTemplatedDecl()->isStaticDataMember() &&((void)0)
       "Only static data member templates are allowed.")((void)0);

// Create a local instantiation scope for this variable template, which
// will contain the instantiations of the template parameters.
LocalInstantiationScope Scope(SemaRef);
TemplateParameterList *TempParams = D->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

VarDecl *Pattern = D->getTemplatedDecl();
VarTemplateDecl *PrevVarTemplate = nullptr;

if (getPreviousDeclForInstantiation(Pattern)) {
  DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());
  if (!Found.empty())
    PrevVarTemplate = dyn_cast<VarTemplateDecl>(Found.front());
}

VarDecl *VarInst =
    cast_or_null<VarDecl>(VisitVarDecl(Pattern,
                                       /*InstantiatingVarTemplate=*/true));
if (!VarInst) return nullptr;

DeclContext *DC = Owner;

VarTemplateDecl *Inst = VarTemplateDecl::Create(
    SemaRef.Context, DC, D->getLocation(), D->getIdentifier(), InstParams,
    VarInst);
VarInst->setDescribedVarTemplate(Inst);
Inst->setPreviousDecl(PrevVarTemplate);

Inst->setAccess(D->getAccess());
if (!PrevVarTemplate)
  Inst->setInstantiatedFromMemberTemplate(D);

if (D->isOutOfLine()) {
  Inst->setLexicalDeclContext(D->getLexicalDeclContext());
  VarInst->setLexicalDeclContext(D->getLexicalDeclContext());
}

Owner->addDecl(Inst);

if (!PrevVarTemplate) {
  // Queue up any out-of-line partial specializations of this member
  // variable template; the client will force their instantiation once
  // the enclosing class has been instantiated.
  SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
  D->getPartialSpecializations(PartialSpecs);
  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)
    if (PartialSpecs[I]->getFirstDecl()->isOutOfLine())
      OutOfLineVarPartialSpecs.push_back(
          std::make_pair(Inst, PartialSpecs[I]));
}

return Inst;
1742}

1744Decl *TemplateDeclInstantiator::VisitVarTemplatePartialSpecializationDecl(
  VarTemplatePartialSpecializationDecl *D) {
assert(D->isStaticDataMember() &&((void)0)
       "Only static data member templates are allowed.")((void)0);

VarTemplateDecl *VarTemplate = D->getSpecializedTemplate();

// Lookup the already-instantiated declaration and return that.
DeclContext::lookup_result Found = Owner->lookup(VarTemplate->getDeclName());
assert(!Found.empty() && "Instantiation found nothing?")((void)0);

VarTemplateDecl *InstVarTemplate = dyn_cast<VarTemplateDecl>(Found.front());
assert(InstVarTemplate && "Instantiation did not find a variable template?")((void)0);

if (VarTemplatePartialSpecializationDecl *Result =
        InstVarTemplate->findPartialSpecInstantiatedFromMember(D))
  return Result;

return InstantiateVarTemplatePartialSpecialization(InstVarTemplate, D);
1763}

1765Decl *
1766TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
// Create a local instantiation scope for this function template, which
// will contain the instantiations of the template parameters and then get
// merged with the local instantiation scope for the function template
// itself.
LocalInstantiationScope Scope(SemaRef);

TemplateParameterList *TempParams = D->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

FunctionDecl *Instantiated = nullptr;
if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))
  Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,
                                                               InstParams));
else
  Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(
                                                        D->getTemplatedDecl(),
                                                              InstParams));

if (!Instantiated)
  return nullptr;

// Link the instantiated function template declaration to the function
// template from which it was instantiated.
FunctionTemplateDecl *InstTemplate
  = Instantiated->getDescribedFunctionTemplate();
InstTemplate->setAccess(D->getAccess());
assert(InstTemplate &&((void)0)
       "VisitFunctionDecl/CXXMethodDecl didn't create a template!")((void)0);

bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);

// Link the instantiation back to the pattern *unless* this is a
// non-definition friend declaration.
if (!InstTemplate->getInstantiatedFromMemberTemplate() &&
    !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))
  InstTemplate->setInstantiatedFromMemberTemplate(D);

// Make declarations visible in the appropriate context.
if (!isFriend) {
  Owner->addDecl(InstTemplate);
} else if (InstTemplate->getDeclContext()->isRecord() &&
           !getPreviousDeclForInstantiation(D)) {
  SemaRef.CheckFriendAccess(InstTemplate);
}

return InstTemplate;
1815}

1817Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
CXXRecordDecl *PrevDecl = nullptr;
if (D->isInjectedClassName())
  PrevDecl = cast<CXXRecordDecl>(Owner);
else if (CXXRecordDecl *PatternPrev = getPreviousDeclForInstantiation(D)) {
  NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),
                                                 PatternPrev,
                                                 TemplateArgs);
  if (!Prev) return nullptr;
  PrevDecl = cast<CXXRecordDecl>(Prev);
}

CXXRecordDecl *Record = nullptr;
if (D->isLambda())
  Record = CXXRecordDecl::CreateLambda(
      SemaRef.Context, Owner, D->getLambdaTypeInfo(), D->getLocation(),
      D->isDependentLambda(), D->isGenericLambda(),
      D->getLambdaCaptureDefault());
else
  Record = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,
                                 D->getBeginLoc(), D->getLocation(),
                                 D->getIdentifier(), PrevDecl);

// Substitute the nested name specifier, if any.
if (SubstQualifier(D, Record))
  return nullptr;

SemaRef.InstantiateAttrsForDecl(TemplateArgs, D, Record, LateAttrs,
                                                            StartingScope);

Record->setImplicit(D->isImplicit());
// FIXME: Check against AS_none is an ugly hack to work around the issue that
// the tag decls introduced by friend class declarations don't have an access
// specifier. Remove once this area of the code gets sorted out.
if (D->getAccess() != AS_none)
  Record->setAccess(D->getAccess());
if (!D->isInjectedClassName())
  Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);

// If the original function was part of a friend declaration,
// inherit its namespace state.
if (D->getFriendObjectKind())
  Record->setObjectOfFriendDecl();

// Make sure that anonymous structs and unions are recorded.
if (D->isAnonymousStructOrUnion())
  Record->setAnonymousStructOrUnion(true);

if (D->isLocalClass())
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);

// Forward the mangling number from the template to the instantiated decl.
SemaRef.Context.setManglingNumber(Record,
                                  SemaRef.Context.getManglingNumber(D));

// See if the old tag was defined along with a declarator.
// If it did, mark the new tag as being associated with that declarator.
if (DeclaratorDecl *DD = SemaRef.Context.getDeclaratorForUnnamedTagDecl(D))
  SemaRef.Context.addDeclaratorForUnnamedTagDecl(Record, DD);

// See if the old tag was defined along with a typedef.
// If it did, mark the new tag as being associated with that typedef.
if (TypedefNameDecl *TND = SemaRef.Context.getTypedefNameForUnnamedTagDecl(D))
  SemaRef.Context.addTypedefNameForUnnamedTagDecl(Record, TND);

Owner->addDecl(Record);

// DR1484 clarifies that the members of a local class are instantiated as part
// of the instantiation of their enclosing entity.
if (D->isCompleteDefinition() && D->isLocalClass()) {
  Sema::LocalEagerInstantiationScope LocalInstantiations(SemaRef);

  SemaRef.InstantiateClass(D->getLocation(), Record, D, TemplateArgs,
                           TSK_ImplicitInstantiation,
                           /*Complain=*/true);

  // For nested local classes, we will instantiate the members when we
  // reach the end of the outermost (non-nested) local class.
  if (!D->isCXXClassMember())
    SemaRef.InstantiateClassMembers(D->getLocation(), Record, TemplateArgs,
                                    TSK_ImplicitInstantiation);

  // This class may have local implicit instantiations that need to be
  // performed within this scope.
  LocalInstantiations.perform();
}

SemaRef.DiagnoseUnusedNestedTypedefs(Record);

return Record;
1907}

1909/// Adjust the given function type for an instantiation of the
1910/// given declaration, to cope with modifications to the function's type that
1911/// aren't reflected in the type-source information.
1912///
1913/// \param D The declaration we're instantiating.
1914/// \param TInfo The already-instantiated type.
1915static QualType adjustFunctionTypeForInstantiation(ASTContext &Context,
                                                 FunctionDecl *D,
                                                 TypeSourceInfo *TInfo) {
const FunctionProtoType *OrigFunc
  = D->getType()->castAs<FunctionProtoType>();
const FunctionProtoType *NewFunc
  = TInfo->getType()->castAs<FunctionProtoType>();
if (OrigFunc->getExtInfo() == NewFunc->getExtInfo())
  return TInfo->getType();

FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();
NewEPI.ExtInfo = OrigFunc->getExtInfo();
return Context.getFunctionType(NewFunc->getReturnType(),
                               NewFunc->getParamTypes(), NewEPI);
1929}

1931/// Normal class members are of more specific types and therefore
1932/// don't make it here.  This function serves three purposes:
1933///   1) instantiating function templates
1934///   2) substituting friend declarations
1935///   3) substituting deduction guide declarations for nested class templates
1936Decl *TemplateDeclInstantiator::VisitFunctionDecl(
  FunctionDecl *D, TemplateParameterList *TemplateParams,
  RewriteKind FunctionRewriteKind) {
// Check whether there is already a function template specialization for
// this declaration.
FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
if (FunctionTemplate && !TemplateParams) {
  ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();

  void *InsertPos = nullptr;
  FunctionDecl *SpecFunc
    = FunctionTemplate->findSpecialization(Innermost, InsertPos);

  // If we already have a function template specialization, return it.
  if (SpecFunc)
    return SpecFunc;
}

bool isFriend;
if (FunctionTemplate)
  isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
else
  isFriend = (D->getFriendObjectKind() != Decl::FOK_None);

bool MergeWithParentScope = (TemplateParams != nullptr) ||
  Owner->isFunctionOrMethod() ||
  !(isa<Decl>(Owner) &&
    cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);

ExplicitSpecifier InstantiatedExplicitSpecifier;
if (auto *DGuide = dyn_cast<CXXDeductionGuideDecl>(D)) {
  InstantiatedExplicitSpecifier = instantiateExplicitSpecifier(
      SemaRef, TemplateArgs, DGuide->getExplicitSpecifier(), DGuide);
  if (InstantiatedExplicitSpecifier.isInvalid())
    return nullptr;
}

SmallVector<ParmVarDecl *, 4> Params;
TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
if (!TInfo)
  return nullptr;
QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);

if (TemplateParams && TemplateParams->size()) {
  auto *LastParam =
      dyn_cast<TemplateTypeParmDecl>(TemplateParams->asArray().back());
  if (LastParam && LastParam->isImplicit() &&
      LastParam->hasTypeConstraint()) {
    // In abbreviated templates, the type-constraints of invented template
    // type parameters are instantiated with the function type, invalidating
    // the TemplateParameterList which relied on the template type parameter
    // not having a type constraint. Recreate the TemplateParameterList with
    // the updated parameter list.
    TemplateParams = TemplateParameterList::Create(
        SemaRef.Context, TemplateParams->getTemplateLoc(),
        TemplateParams->getLAngleLoc(), TemplateParams->asArray(),
        TemplateParams->getRAngleLoc(), TemplateParams->getRequiresClause());
  }
}

NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
if (QualifierLoc) {
  QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
                                                     TemplateArgs);
  if (!QualifierLoc)
    return nullptr;
}

// FIXME: Concepts: Do not substitute into constraint expressions
Expr *TrailingRequiresClause = D->getTrailingRequiresClause();
if (TrailingRequiresClause) {
  EnterExpressionEvaluationContext ConstantEvaluated(
      SemaRef, Sema::ExpressionEvaluationContext::Unevaluated);
  ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause,
                                         TemplateArgs);
  if (SubstRC.isInvalid())
    return nullptr;
  TrailingRequiresClause = SubstRC.get();
  if (!SemaRef.CheckConstraintExpression(TrailingRequiresClause))
    return nullptr;
}

// If we're instantiating a local function declaration, put the result
// in the enclosing namespace; otherwise we need to find the instantiated
// context.
DeclContext *DC;
if (D->isLocalExternDecl()) {
  DC = Owner;
  SemaRef.adjustContextForLocalExternDecl(DC);
} else if (isFriend && QualifierLoc) {
  CXXScopeSpec SS;
  SS.Adopt(QualifierLoc);
  DC = SemaRef.computeDeclContext(SS);
  if (!DC) return nullptr;
} else {
  DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),
                                       TemplateArgs);
}

DeclarationNameInfo NameInfo
  = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);

if (FunctionRewriteKind != RewriteKind::None)
  adjustForRewrite(FunctionRewriteKind, D, T, TInfo, NameInfo);

FunctionDecl *Function;
if (auto *DGuide = dyn_cast<CXXDeductionGuideDecl>(D)) {
  Function = CXXDeductionGuideDecl::Create(
      SemaRef.Context, DC, D->getInnerLocStart(),
      InstantiatedExplicitSpecifier, NameInfo, T, TInfo,
      D->getSourceRange().getEnd());
  if (DGuide->isCopyDeductionCandidate())
    cast<CXXDeductionGuideDecl>(Function)->setIsCopyDeductionCandidate();
  Function->setAccess(D->getAccess());
} else {
  Function = FunctionDecl::Create(
      SemaRef.Context, DC, D->getInnerLocStart(), NameInfo, T, TInfo,
      D->getCanonicalDecl()->getStorageClass(), D->isInlineSpecified(),
      D->hasWrittenPrototype(), D->getConstexprKind(),
      TrailingRequiresClause);
  Function->setRangeEnd(D->getSourceRange().getEnd());
}

if (D->isInlined())
  Function->setImplicitlyInline();

if (QualifierLoc)
  Function->setQualifierInfo(QualifierLoc);

if (D->isLocalExternDecl())
  Function->setLocalExternDecl();

DeclContext *LexicalDC = Owner;
if (!isFriend && D->isOutOfLine() && !D->isLocalExternDecl()) {
  assert(D->getDeclContext()->isFileContext())((void)0);
  LexicalDC = D->getDeclContext();
}

Function->setLexicalDeclContext(LexicalDC);

// Attach the parameters
for (unsigned P = 0; P < Params.size(); ++P)
  if (Params[P])
    Params[P]->setOwningFunction(Function);
Function->setParams(Params);

if (TrailingRequiresClause)
  Function->setTrailingRequiresClause(TrailingRequiresClause);

if (TemplateParams) {
  // Our resulting instantiation is actually a function template, since we
  // are substituting only the outer template parameters. For example, given
  //
  //   template<typename T>
  //   struct X {
  //     template<typename U> friend void f(T, U);
  //   };
  //
  //   X<int> x;
  //
  // We are instantiating the friend function template "f" within X<int>,
  // which means substituting int for T, but leaving "f" as a friend function
  // template.
  // Build the function template itself.
  FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,
                                                  Function->getLocation(),
                                                  Function->getDeclName(),
                                                  TemplateParams, Function);
  Function->setDescribedFunctionTemplate(FunctionTemplate);

  FunctionTemplate->setLexicalDeclContext(LexicalDC);

  if (isFriend && D->isThisDeclarationADefinition()) {
    FunctionTemplate->setInstantiatedFromMemberTemplate(
                                         D->getDescribedFunctionTemplate());
  }
} else if (FunctionTemplate) {
  // Record this function template specialization.
  ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();
  Function->setFunctionTemplateSpecialization(FunctionTemplate,
                          TemplateArgumentList::CreateCopy(SemaRef.Context,
                                                           Innermost),
                                              /*InsertPos=*/nullptr);
} else if (isFriend && D->isThisDeclarationADefinition()) {
  // Do not connect the friend to the template unless it's actually a
  // definition. We don't want non-template functions to be marked as being
  // template instantiations.
  Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
}

if (isFriend) {
  Function->setObjectOfFriendDecl();
  if (FunctionTemplateDecl *FT = Function->getDescribedFunctionTemplate())
    FT->setObjectOfFriendDecl();
}

if (InitFunctionInstantiation(Function, D))
  Function->setInvalidDecl();

bool IsExplicitSpecialization = false;

LookupResult Previous(
    SemaRef, Function->getDeclName(), SourceLocation(),
    D->isLocalExternDecl() ? Sema::LookupRedeclarationWithLinkage
                           : Sema::LookupOrdinaryName,
    D->isLocalExternDecl() ? Sema::ForExternalRedeclaration
                           : SemaRef.forRedeclarationInCurContext());

if (DependentFunctionTemplateSpecializationInfo *Info
      = D->getDependentSpecializationInfo()) {
  assert(isFriend && "non-friend has dependent specialization info?")((void)0);

  // Instantiate the explicit template arguments.
  TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
                                        Info->getRAngleLoc());
  if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
                    ExplicitArgs, TemplateArgs))
    return nullptr;

  // Map the candidate templates to their instantiations.
  for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
    Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
                                              Info->getTemplate(I),
                                              TemplateArgs);
    if (!Temp) return nullptr;

    Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
  }

  if (SemaRef.CheckFunctionTemplateSpecialization(Function,
                                                  &ExplicitArgs,
                                                  Previous))
    Function->setInvalidDecl();

  IsExplicitSpecialization = true;
} else if (const ASTTemplateArgumentListInfo *Info =
               D->getTemplateSpecializationArgsAsWritten()) {
  // The name of this function was written as a template-id.
  SemaRef.LookupQualifiedName(Previous, DC);

  // Instantiate the explicit template arguments.
  TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
                                        Info->getRAngleLoc());
  if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
                    ExplicitArgs, TemplateArgs))
    return nullptr;

  if (SemaRef.CheckFunctionTemplateSpecialization(Function,
                                                  &ExplicitArgs,
                                                  Previous))
    Function->setInvalidDecl();

  IsExplicitSpecialization = true;
} else if (TemplateParams || !FunctionTemplate) {
  // Look only into the namespace where the friend would be declared to
  // find a previous declaration. This is the innermost enclosing namespace,
  // as described in ActOnFriendFunctionDecl.
  SemaRef.LookupQualifiedName(Previous, DC->getRedeclContext());

  // In C++, the previous declaration we find might be a tag type
  // (class or enum). In this case, the new declaration will hide the
  // tag type. Note that this does does not apply if we're declaring a
  // typedef (C++ [dcl.typedef]p4).
  if (Previous.isSingleTagDecl())
    Previous.clear();

  // Filter out previous declarations that don't match the scope. The only
  // effect this has is to remove declarations found in inline namespaces
  // for friend declarations with unqualified names.
  SemaRef.FilterLookupForScope(Previous, DC, /*Scope*/ nullptr,
                               /*ConsiderLinkage*/ true,
                               QualifierLoc.hasQualifier());
}

SemaRef.CheckFunctionDeclaration(/*Scope*/ nullptr, Function, Previous,
                                 IsExplicitSpecialization);

// Check the template parameter list against the previous declaration. The
// goal here is to pick up default arguments added since the friend was
// declared; we know the template parameter lists match, since otherwise
// we would not have picked this template as the previous declaration.
if (isFriend && TemplateParams && FunctionTemplate->getPreviousDecl()) {
  SemaRef.CheckTemplateParameterList(
      TemplateParams,
      FunctionTemplate->getPreviousDecl()->getTemplateParameters(),
      Function->isThisDeclarationADefinition()
          ? Sema::TPC_FriendFunctionTemplateDefinition
          : Sema::TPC_FriendFunctionTemplate);
}

// If we're introducing a friend definition after the first use, trigger
// instantiation.
// FIXME: If this is a friend function template definition, we should check
// to see if any specializations have been used.
if (isFriend && D->isThisDeclarationADefinition() && Function->isUsed(false)) {
  if (MemberSpecializationInfo *MSInfo =
          Function->getMemberSpecializationInfo()) {
    if (MSInfo->getPointOfInstantiation().isInvalid()) {
      SourceLocation Loc = D->getLocation(); // FIXME
      MSInfo->setPointOfInstantiation(Loc);
      SemaRef.PendingLocalImplicitInstantiations.push_back(
          std::make_pair(Function, Loc));
    }
  }
}

if (D->isExplicitlyDefaulted()) {
  if (SubstDefaultedFunction(Function, D))
    return nullptr;
}
if (D->isDeleted())
  SemaRef.SetDeclDeleted(Function, D->getLocation());

NamedDecl *PrincipalDecl =
    (TemplateParams ? cast<NamedDecl>(FunctionTemplate) : Function);

// If this declaration lives in a different context from its lexical context,
// add it to the corresponding lookup table.
if (isFriend ||
    (Function->isLocalExternDecl() && !Function->getPreviousDecl()))
  DC->makeDeclVisibleInContext(PrincipalDecl);

if (Function->isOverloadedOperator() && !DC->isRecord() &&
    PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
  PrincipalDecl->setNonMemberOperator();

return Function;
2264}

2266Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(
  CXXMethodDecl *D, TemplateParameterList *TemplateParams,
  Optional<const ASTTemplateArgumentListInfo *> ClassScopeSpecializationArgs,
  RewriteKind FunctionRewriteKind) {
FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
if (FunctionTemplate && !TemplateParams) {
  // We are creating a function template specialization from a function
  // template. Check whether there is already a function template
  // specialization for this particular set of template arguments.
  ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();

  void *InsertPos = nullptr;
  FunctionDecl *SpecFunc
    = FunctionTemplate->findSpecialization(Innermost, InsertPos);

  // If we already have a function template specialization, return it.
  if (SpecFunc)
    return SpecFunc;
}

bool isFriend;
if (FunctionTemplate)
  isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);
else
  isFriend = (D->getFriendObjectKind() != Decl::FOK_None);

bool MergeWithParentScope = (TemplateParams != nullptr) ||
  !(isa<Decl>(Owner) &&
    cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());
LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);

// Instantiate enclosing template arguments for friends.
SmallVector<TemplateParameterList *, 4> TempParamLists;
unsigned NumTempParamLists = 0;
if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
  TempParamLists.resize(NumTempParamLists);
  for (unsigned I = 0; I != NumTempParamLists; ++I) {
    TemplateParameterList *TempParams = D->getTemplateParameterList(I);
    TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
    if (!InstParams)
      return nullptr;
    TempParamLists[I] = InstParams;
  }
}

ExplicitSpecifier InstantiatedExplicitSpecifier =
    instantiateExplicitSpecifier(SemaRef, TemplateArgs,
                                 ExplicitSpecifier::getFromDecl(D), D);
if (InstantiatedExplicitSpecifier.isInvalid())
  return nullptr;

// Implicit destructors/constructors created for local classes in
// DeclareImplicit* (see SemaDeclCXX.cpp) might not have an associated TSI.
// Unfortunately there isn't enough context in those functions to
// conditionally populate the TSI without breaking non-template related use
// cases. Populate TSIs prior to calling SubstFunctionType to make sure we get
// a proper transformation.
if (cast<CXXRecordDecl>(D->getParent())->isLambda() &&
    !D->getTypeSourceInfo() &&
    isa<CXXConstructorDecl, CXXDestructorDecl>(D)) {
  TypeSourceInfo *TSI =
      SemaRef.Context.getTrivialTypeSourceInfo(D->getType());
  D->setTypeSourceInfo(TSI);
}

SmallVector<ParmVarDecl *, 4> Params;
TypeSourceInfo *TInfo = SubstFunctionType(D, Params);
if (!TInfo)
  return nullptr;
QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);

if (TemplateParams && TemplateParams->size()) {
  auto *LastParam =
      dyn_cast<TemplateTypeParmDecl>(TemplateParams->asArray().back());
  if (LastParam && LastParam->isImplicit() &&
      LastParam->hasTypeConstraint()) {
    // In abbreviated templates, the type-constraints of invented template
    // type parameters are instantiated with the function type, invalidating
    // the TemplateParameterList which relied on the template type parameter
    // not having a type constraint. Recreate the TemplateParameterList with
    // the updated parameter list.
    TemplateParams = TemplateParameterList::Create(
        SemaRef.Context, TemplateParams->getTemplateLoc(),
        TemplateParams->getLAngleLoc(), TemplateParams->asArray(),
        TemplateParams->getRAngleLoc(), TemplateParams->getRequiresClause());
  }
}

NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();
if (QualifierLoc) {
  QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,
                                               TemplateArgs);
  if (!QualifierLoc)
    return nullptr;
}

// FIXME: Concepts: Do not substitute into constraint expressions
Expr *TrailingRequiresClause = D->getTrailingRequiresClause();
if (TrailingRequiresClause) {
  EnterExpressionEvaluationContext ConstantEvaluated(
      SemaRef, Sema::ExpressionEvaluationContext::Unevaluated);
  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);
  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext,
                                   D->getMethodQualifiers(), ThisContext);
  ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause,
                                         TemplateArgs);
  if (SubstRC.isInvalid())
    return nullptr;
  TrailingRequiresClause = SubstRC.get();
  if (!SemaRef.CheckConstraintExpression(TrailingRequiresClause))
    return nullptr;
}

DeclContext *DC = Owner;
if (isFriend) {
  if (QualifierLoc) {
    CXXScopeSpec SS;
    SS.Adopt(QualifierLoc);
    DC = SemaRef.computeDeclContext(SS);

    if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))
      return nullptr;
  } else {
    DC = SemaRef.FindInstantiatedContext(D->getLocation(),
                                         D->getDeclContext(),
                                         TemplateArgs);
  }
  if (!DC) return nullptr;
}

DeclarationNameInfo NameInfo
  = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);

if (FunctionRewriteKind != RewriteKind::None)
  adjustForRewrite(FunctionRewriteKind, D, T, TInfo, NameInfo);

// Build the instantiated method declaration.
CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
CXXMethodDecl *Method = nullptr;

SourceLocation StartLoc = D->getInnerLocStart();
if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
  Method = CXXConstructorDecl::Create(
      SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,
      InstantiatedExplicitSpecifier, Constructor->isInlineSpecified(), false,
      Constructor->getConstexprKind(), InheritedConstructor(),
      TrailingRequiresClause);
  Method->setRangeEnd(Constructor->getEndLoc());
} else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {
  Method = CXXDestructorDecl::Create(
      SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,
      Destructor->isInlineSpecified(), false, Destructor->getConstexprKind(),
      TrailingRequiresClause);
  Method->setRangeEnd(Destructor->getEndLoc());
  Method->setDeclName(SemaRef.Context.DeclarationNames.getCXXDestructorName(
      SemaRef.Context.getCanonicalType(
          SemaRef.Context.getTypeDeclType(Record))));
} else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {
  Method = CXXConversionDecl::Create(
      SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,
      Conversion->isInlineSpecified(), InstantiatedExplicitSpecifier,
      Conversion->getConstexprKind(), Conversion->getEndLoc(),
      TrailingRequiresClause);
} else {
  StorageClass SC = D->isStatic() ? SC_Static : SC_None;
  Method = CXXMethodDecl::Create(SemaRef.Context, Record, StartLoc, NameInfo,
                                 T, TInfo, SC, D->isInlineSpecified(),
                                 D->getConstexprKind(), D->getEndLoc(),
                                 TrailingRequiresClause);
}

if (D->isInlined())
  Method->setImplicitlyInline();

if (QualifierLoc)
  Method->setQualifierInfo(QualifierLoc);

if (TemplateParams) {
  // Our resulting instantiation is actually a function template, since we
  // are substituting only the outer template parameters. For example, given
  //
  //   template<typename T>
  //   struct X {
  //     template<typename U> void f(T, U);
  //   };
  //
  //   X<int> x;
  //
  // We are instantiating the member template "f" within X<int>, which means
  // substituting int for T, but leaving "f" as a member function template.
  // Build the function template itself.
  FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,
                                                  Method->getLocation(),
                                                  Method->getDeclName(),
                                                  TemplateParams, Method);
  if (isFriend) {
    FunctionTemplate->setLexicalDeclContext(Owner);
    FunctionTemplate->setObjectOfFriendDecl();
  } else if (D->isOutOfLine())
    FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
  Method->setDescribedFunctionTemplate(FunctionTemplate);
} else if (FunctionTemplate) {
  // Record this function template specialization.
  ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();
  Method->setFunctionTemplateSpecialization(FunctionTemplate,
                       TemplateArgumentList::CreateCopy(SemaRef.Context,
                                                        Innermost),
                                            /*InsertPos=*/nullptr);
} else if (!isFriend) {
  // Record that this is an instantiation of a member function.
  Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
}

// If we are instantiating a member function defined
// out-of-line, the instantiation will have the same lexical
// context (which will be a namespace scope) as the template.
if (isFriend) {
  if (NumTempParamLists)
    Method->setTemplateParameterListsInfo(
        SemaRef.Context,
        llvm::makeArrayRef(TempParamLists.data(), NumTempParamLists));

  Method->setLexicalDeclContext(Owner);
  Method->setObjectOfFriendDecl();
} else if (D->isOutOfLine())
  Method->setLexicalDeclContext(D->getLexicalDeclContext());

// Attach the parameters
for (unsigned P = 0; P < Params.size(); ++P)
  Params[P]->setOwningFunction(Method);
Method->setParams(Params);

if (InitMethodInstantiation(Method, D))
  Method->setInvalidDecl();

LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,
                      Sema::ForExternalRedeclaration);

bool IsExplicitSpecialization = false;

// If the name of this function was written as a template-id, instantiate
// the explicit template arguments.
if (DependentFunctionTemplateSpecializationInfo *Info
      = D->getDependentSpecializationInfo()) {
  assert(isFriend && "non-friend has dependent specialization info?")((void)0);

  // Instantiate the explicit template arguments.
  TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
                                        Info->getRAngleLoc());
  if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
                    ExplicitArgs, TemplateArgs))
    return nullptr;

  // Map the candidate templates to their instantiations.
  for (unsigned I = 0, E = Info->getNumTemplates(); I != E; ++I) {
    Decl *Temp = SemaRef.FindInstantiatedDecl(D->getLocation(),
                                              Info->getTemplate(I),
                                              TemplateArgs);
    if (!Temp) return nullptr;

    Previous.addDecl(cast<FunctionTemplateDecl>(Temp));
  }

  if (SemaRef.CheckFunctionTemplateSpecialization(Method,
                                                  &ExplicitArgs,
                                                  Previous))
    Method->setInvalidDecl();

  IsExplicitSpecialization = true;
} else if (const ASTTemplateArgumentListInfo *Info =
               ClassScopeSpecializationArgs.getValueOr(
                   D->getTemplateSpecializationArgsAsWritten())) {
  SemaRef.LookupQualifiedName(Previous, DC);

  TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
                                        Info->getRAngleLoc());
  if (SemaRef.Subst(Info->getTemplateArgs(), Info->getNumTemplateArgs(),
                    ExplicitArgs, TemplateArgs))
    return nullptr;

  if (SemaRef.CheckFunctionTemplateSpecialization(Method,
                                                  &ExplicitArgs,
                                                  Previous))
    Method->setInvalidDecl();

  IsExplicitSpecialization = true;
} else if (ClassScopeSpecializationArgs) {
  // Class-scope explicit specialization written without explicit template
  // arguments.
  SemaRef.LookupQualifiedName(Previous, DC);
  if (SemaRef.CheckFunctionTemplateSpecialization(Method, nullptr, Previous))
    Method->setInvalidDecl();

  IsExplicitSpecialization = true;
} else if (!FunctionTemplate || TemplateParams || isFriend) {
  SemaRef.LookupQualifiedName(Previous, Record);

  // In C++, the previous declaration we find might be a tag type
  // (class or enum). In this case, the new declaration will hide the
  // tag type. Note that this does does not apply if we're declaring a
  // typedef (C++ [dcl.typedef]p4).
  if (Previous.isSingleTagDecl())
    Previous.clear();
}

SemaRef.CheckFunctionDeclaration(nullptr, Method, Previous,
                                 IsExplicitSpecialization);

if (D->isPure())
  SemaRef.CheckPureMethod(Method, SourceRange());

// Propagate access.  For a non-friend declaration, the access is
// whatever we're propagating from.  For a friend, it should be the
// previous declaration we just found.
if (isFriend && Method->getPreviousDecl())
  Method->setAccess(Method->getPreviousDecl()->getAccess());
else
  Method->setAccess(D->getAccess());
if (FunctionTemplate)
  FunctionTemplate->setAccess(Method->getAccess());

SemaRef.CheckOverrideControl(Method);

// If a function is defined as defaulted or deleted, mark it as such now.
if (D->isExplicitlyDefaulted()) {
  if (SubstDefaultedFunction(Method, D))
    return nullptr;
}
if (D->isDeletedAsWritten())
  SemaRef.SetDeclDeleted(Method, Method->getLocation());

// If this is an explicit specialization, mark the implicitly-instantiated
// template specialization as being an explicit specialization too.
// FIXME: Is this necessary?
if (IsExplicitSpecialization && !isFriend)
  SemaRef.CompleteMemberSpecialization(Method, Previous);

// If there's a function template, let our caller handle it.
if (FunctionTemplate) {
  // do nothing

// Don't hide a (potentially) valid declaration with an invalid one.
} else if (Method->isInvalidDecl() && !Previous.empty()) {
  // do nothing

// Otherwise, check access to friends and make them visible.
} else if (isFriend) {
  // We only need to re-check access for methods which we didn't
  // manage to match during parsing.
  if (!D->getPreviousDecl())
    SemaRef.CheckFriendAccess(Method);

  Record->makeDeclVisibleInContext(Method);

// Otherwise, add the declaration.  We don't need to do this for
// class-scope specializations because we'll have matched them with
// the appropriate template.
} else {
  Owner->addDecl(Method);
}

// PR17480: Honor the used attribute to instantiate member function
// definitions
if (Method->hasAttr<UsedAttr>()) {
  if (const auto *A = dyn_cast<CXXRecordDecl>(Owner)) {
    SourceLocation Loc;
    if (const MemberSpecializationInfo *MSInfo =
            A->getMemberSpecializationInfo())
      Loc = MSInfo->getPointOfInstantiation();
    else if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(A))
      Loc = Spec->getPointOfInstantiation();
    SemaRef.MarkFunctionReferenced(Loc, Method);
  }
}

return Method;
2642}

2644Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
return VisitCXXMethodDecl(D);
2646}

2648Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
return VisitCXXMethodDecl(D);
2650}

2652Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {
return VisitCXXMethodDecl(D);
2654}

2656Decl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0, None,
                                /*ExpectParameterPack=*/ false);
2659}

2661Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
                                                  TemplateTypeParmDecl *D) {
assert(D->getTypeForDecl()->isTemplateTypeParmType())((void)0);

Optional<unsigned> NumExpanded;

if (const TypeConstraint *TC = D->getTypeConstraint()) {
  if (D->isPackExpansion() && !D->isExpandedParameterPack()) {
    assert(TC->getTemplateArgsAsWritten() &&((void)0)
           "type parameter can only be an expansion when explicit arguments "((void)0)
           "are specified")((void)0);
    // The template type parameter pack's type is a pack expansion of types.
    // Determine whether we need to expand this parameter pack into separate
    // types.
    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
    for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
      SemaRef.collectUnexpandedParameterPacks(ArgLoc, Unexpanded);

    // Determine whether the set of unexpanded parameter packs can and should
    // be expanded.
    bool Expand = true;
    bool RetainExpansion = false;
    if (SemaRef.CheckParameterPacksForExpansion(
            cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
                ->getEllipsisLoc(),
            SourceRange(TC->getConceptNameLoc(),
                        TC->hasExplicitTemplateArgs() ?
                        TC->getTemplateArgsAsWritten()->getRAngleLoc() :
                        TC->getConceptNameInfo().getEndLoc()),
            Unexpanded, TemplateArgs, Expand, RetainExpansion, NumExpanded))
      return nullptr;
  }
}

TemplateTypeParmDecl *Inst = TemplateTypeParmDecl::Create(
    SemaRef.Context, Owner, D->getBeginLoc(), D->getLocation(),
    D->getDepth() - TemplateArgs.getNumSubstitutedLevels(), D->getIndex(),
    D->getIdentifier(), D->wasDeclaredWithTypename(), D->isParameterPack(),
    D->hasTypeConstraint(), NumExpanded);

Inst->setAccess(AS_public);
Inst->setImplicit(D->isImplicit());
if (auto *TC = D->getTypeConstraint()) {
  if (!D->isImplicit()) {
    // Invented template parameter type constraints will be instantiated with
    // the corresponding auto-typed parameter as it might reference other
    // parameters.

    // 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 (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
                        TemplArgInfo->NumTemplateArgs,
                        InstArgs, TemplateArgs))
        return nullptr;
    }
    if (SemaRef.AttachTypeConstraint(
            TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
            TC->getNamedConcept(), &InstArgs, Inst,
            D->isParameterPack()
                ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
                    ->getEllipsisLoc()
                : SourceLocation()))
      return nullptr;
  }
}
if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
  TypeSourceInfo *InstantiatedDefaultArg =
      SemaRef.SubstType(D->getDefaultArgumentInfo(), TemplateArgs,
                        D->getDefaultArgumentLoc(), D->getDeclName());
  if (InstantiatedDefaultArg)
    Inst->setDefaultArgument(InstantiatedDefaultArg);
}

// Introduce this template parameter's instantiation into the instantiation
// scope.
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);

return Inst;
2746}

2748Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(
                                               NonTypeTemplateParmDecl *D) {
// Substitute into the type of the non-type template parameter.
TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();
SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;
SmallVector<QualType, 4> ExpandedParameterPackTypes;
bool IsExpandedParameterPack = false;
TypeSourceInfo *DI;
QualType T;
bool Invalid = false;

if (D->isExpandedParameterPack()) {
  // The non-type template parameter pack is an already-expanded pack
  // expansion of types. Substitute into each of the expanded types.
  ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());
  ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());
  for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
    TypeSourceInfo *NewDI =
        SemaRef.SubstType(D->getExpansionTypeSourceInfo(I), TemplateArgs,
                          D->getLocation(), D->getDeclName());
    if (!NewDI)
      return nullptr;

    QualType NewT =
        SemaRef.CheckNonTypeTemplateParameterType(NewDI, D->getLocation());
    if (NewT.isNull())
      return nullptr;

    ExpandedParameterPackTypesAsWritten.push_back(NewDI);
    ExpandedParameterPackTypes.push_back(NewT);
  }

  IsExpandedParameterPack = true;
  DI = D->getTypeSourceInfo();
  T = DI->getType();
} else if (D->isPackExpansion()) {
  // The non-type template parameter pack's type is a pack expansion of types.
  // Determine whether we need to expand this parameter pack into separate
  // types.
  PackExpansionTypeLoc Expansion = TL.castAs<PackExpansionTypeLoc>();
  TypeLoc Pattern = Expansion.getPatternLoc();
  SmallVector<UnexpandedParameterPack, 2> Unexpanded;
  SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);

  // Determine whether the set of unexpanded parameter packs can and should
  // be expanded.
  bool Expand = true;
  bool RetainExpansion = false;
  Optional<unsigned> OrigNumExpansions
    = Expansion.getTypePtr()->getNumExpansions();
  Optional<unsigned> NumExpansions = OrigNumExpansions;
  if (SemaRef.CheckParameterPacksForExpansion(Expansion.getEllipsisLoc(),
                                              Pattern.getSourceRange(),
                                              Unexpanded,
                                              TemplateArgs,
                                              Expand, RetainExpansion,
                                              NumExpansions))
    return nullptr;

  if (Expand) {
    for (unsigned I = 0; I != *NumExpansions; ++I) {
      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
      TypeSourceInfo *NewDI = SemaRef.SubstType(Pattern, TemplateArgs,
                                                D->getLocation(),
                                                D->getDeclName());
      if (!NewDI)
        return nullptr;

      QualType NewT =
          SemaRef.CheckNonTypeTemplateParameterType(NewDI, D->getLocation());
      if (NewT.isNull())
        return nullptr;

      ExpandedParameterPackTypesAsWritten.push_back(NewDI);
      ExpandedParameterPackTypes.push_back(NewT);
    }

    // Note that we have an expanded parameter pack. The "type" of this
    // expanded parameter pack is the original expansion type, but callers
    // will end up using the expanded parameter pack types for type-checking.
    IsExpandedParameterPack = true;
    DI = D->getTypeSourceInfo();
    T = DI->getType();
  } else {
    // We cannot fully expand the pack expansion now, so substitute into the
    // pattern and create a new pack expansion type.
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
    TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,
                                                   D->getLocation(),
                                                   D->getDeclName());
    if (!NewPattern)
      return nullptr;

    SemaRef.CheckNonTypeTemplateParameterType(NewPattern, D->getLocation());
    DI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),
                                    NumExpansions);
    if (!DI)
      return nullptr;

    T = DI->getType();
  }
} else {
  // Simple case: substitution into a parameter that is not a parameter pack.
  DI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
                         D->getLocation(), D->getDeclName());
  if (!DI)
    return nullptr;

  // Check that this type is acceptable for a non-type template parameter.
  T = SemaRef.CheckNonTypeTemplateParameterType(DI, D->getLocation());
  if (T.isNull()) {
    T = SemaRef.Context.IntTy;
    Invalid = true;
  }
}

NonTypeTemplateParmDecl *Param;
if (IsExpandedParameterPack)
  Param = NonTypeTemplateParmDecl::Create(
      SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),
      D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),
      D->getPosition(), D->getIdentifier(), T, DI, ExpandedParameterPackTypes,
      ExpandedParameterPackTypesAsWritten);
else
  Param = NonTypeTemplateParmDecl::Create(
      SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),
      D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),
      D->getPosition(), D->getIdentifier(), T, D->isParameterPack(), DI);

if (AutoTypeLoc AutoLoc = DI->getTypeLoc().getContainedAutoTypeLoc())
  if (AutoLoc.isConstrained())
    if (SemaRef.AttachTypeConstraint(
            AutoLoc, Param,
            IsExpandedParameterPack
              ? DI->getTypeLoc().getAs<PackExpansionTypeLoc>()
                  .getEllipsisLoc()
              : SourceLocation()))
      Invalid = true;

Param->setAccess(AS_public);
Param->setImplicit(D->isImplicit());
if (Invalid)
  Param->setInvalidDecl();

if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
  EnterExpressionEvaluationContext ConstantEvaluated(
      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  ExprResult Value = SemaRef.SubstExpr(D->getDefaultArgument(), TemplateArgs);
  if (!Value.isInvalid())
    Param->setDefaultArgument(Value.get());
}

// Introduce this template parameter's instantiation into the instantiation
// scope.
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);
return Param;
2904}

2906static void collectUnexpandedParameterPacks(
  Sema &S,
  TemplateParameterList *Params,
  SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
for (const auto &P : *Params) {
  if (P->isTemplateParameterPack())
    continue;
  if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P))
    S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),
                                      Unexpanded);
  if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(P))
    collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),
                                    Unexpanded);
}
2920}

2922Decl *
2923TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(
                                                TemplateTemplateParmDecl *D) {
// Instantiate the template parameter list of the template template parameter.
TemplateParameterList *TempParams = D->getTemplateParameters();
TemplateParameterList *InstParams;
SmallVector<TemplateParameterList*, 8> ExpandedParams;

bool IsExpandedParameterPack = false;

if (D->isExpandedParameterPack()) {
  // The template template parameter pack is an already-expanded pack
  // expansion of template parameters. Substitute into each of the expanded
  // parameters.
  ExpandedParams.reserve(D->getNumExpansionTemplateParameters());
  for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
       I != N; ++I) {
    LocalInstantiationScope Scope(SemaRef);
    TemplateParameterList *Expansion =
      SubstTemplateParams(D->getExpansionTemplateParameters(I));
    if (!Expansion)
      return nullptr;
    ExpandedParams.push_back(Expansion);
  }

  IsExpandedParameterPack = true;
  InstParams = TempParams;
} else if (D->isPackExpansion()) {
  // The template template parameter pack expands to a pack of template
  // template parameters. Determine whether we need to expand this parameter
  // pack into separate parameters.
  SmallVector<UnexpandedParameterPack, 2> Unexpanded;
  collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),
                                  Unexpanded);

  // Determine whether the set of unexpanded parameter packs can and should
  // be expanded.
  bool Expand = true;
  bool RetainExpansion = false;
  Optional<unsigned> NumExpansions;
  if (SemaRef.CheckParameterPacksForExpansion(D->getLocation(),
                                              TempParams->getSourceRange(),
                                              Unexpanded,
                                              TemplateArgs,
                                              Expand, RetainExpansion,
                                              NumExpansions))
    return nullptr;

  if (Expand) {
    for (unsigned I = 0; I != *NumExpansions; ++I) {
      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
      LocalInstantiationScope Scope(SemaRef);
      TemplateParameterList *Expansion = SubstTemplateParams(TempParams);
      if (!Expansion)
        return nullptr;
      ExpandedParams.push_back(Expansion);
    }

    // Note that we have an expanded parameter pack. The "type" of this
    // expanded parameter pack is the original expansion type, but callers
    // will end up using the expanded parameter pack types for type-checking.
    IsExpandedParameterPack = true;
    InstParams = TempParams;
  } else {
    // We cannot fully expand the pack expansion now, so just substitute
    // into the pattern.
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);

    LocalInstantiationScope Scope(SemaRef);
    InstParams = SubstTemplateParams(TempParams);
    if (!InstParams)
      return nullptr;
  }
} else {
  // Perform the actual substitution of template parameters within a new,
  // local instantiation scope.
  LocalInstantiationScope Scope(SemaRef);
  InstParams = SubstTemplateParams(TempParams);
  if (!InstParams)
    return nullptr;
}

// Build the template template parameter.
TemplateTemplateParmDecl *Param;
if (IsExpandedParameterPack)
  Param = TemplateTemplateParmDecl::Create(
      SemaRef.Context, Owner, D->getLocation(),
      D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),
      D->getPosition(), D->getIdentifier(), InstParams, ExpandedParams);
else
  Param = TemplateTemplateParmDecl::Create(
      SemaRef.Context, Owner, D->getLocation(),
      D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),
      D->getPosition(), D->isParameterPack(), D->getIdentifier(), InstParams);
if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
  NestedNameSpecifierLoc QualifierLoc =
      D->getDefaultArgument().getTemplateQualifierLoc();
  QualifierLoc =
      SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgs);
  TemplateName TName = SemaRef.SubstTemplateName(
      QualifierLoc, D->getDefaultArgument().getArgument().getAsTemplate(),
      D->getDefaultArgument().getTemplateNameLoc(), TemplateArgs);
  if (!TName.isNull())
    Param->setDefaultArgument(
        SemaRef.Context,
        TemplateArgumentLoc(SemaRef.Context, TemplateArgument(TName),
                            D->getDefaultArgument().getTemplateQualifierLoc(),
                            D->getDefaultArgument().getTemplateNameLoc()));
}
Param->setAccess(AS_public);
Param->setImplicit(D->isImplicit());

// Introduce this template parameter's instantiation into the instantiation
// scope.
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);

return Param;
3039}

3041Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
// Using directives are never dependent (and never contain any types or
// expressions), so they require no explicit instantiation work.

UsingDirectiveDecl *Inst
  = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),
                               D->getNamespaceKeyLocation(),
                               D->getQualifierLoc(),
                               D->getIdentLocation(),
                               D->getNominatedNamespace(),
                               D->getCommonAncestor());

// Add the using directive to its declaration context
// only if this is not a function or method.
if (!Owner->isFunctionOrMethod())
  Owner->addDecl(Inst);

return Inst;
3059}

3061Decl *TemplateDeclInstantiator::VisitBaseUsingDecls(BaseUsingDecl *D,
                                                  BaseUsingDecl *Inst,
                                                  LookupResult *Lookup) {

bool isFunctionScope = Owner->isFunctionOrMethod();

for (auto *Shadow : D->shadows()) {
  // FIXME: UsingShadowDecl doesn't preserve its immediate target, so
  // reconstruct it in the case where it matters. Hm, can we extract it from
  // the DeclSpec when parsing and save it in the UsingDecl itself?
  NamedDecl *OldTarget = Shadow->getTargetDecl();
  if (auto *CUSD = dyn_cast<ConstructorUsingShadowDecl>(Shadow))
    if (auto *BaseShadow = CUSD->getNominatedBaseClassShadowDecl())
      OldTarget = BaseShadow;

  NamedDecl *InstTarget = nullptr;
  if (auto *EmptyD =
          dyn_cast<UnresolvedUsingIfExistsDecl>(Shadow->getTargetDecl())) {
    InstTarget = UnresolvedUsingIfExistsDecl::Create(
        SemaRef.Context, Owner, EmptyD->getLocation(), EmptyD->getDeclName());
  } else {
    InstTarget = cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(
        Shadow->getLocation(), OldTarget, TemplateArgs));
  }
  if (!InstTarget)
    return nullptr;

  UsingShadowDecl *PrevDecl = nullptr;
  if (Lookup &&
      SemaRef.CheckUsingShadowDecl(Inst, InstTarget, *Lookup, PrevDecl))
    continue;

  if (UsingShadowDecl *OldPrev = getPreviousDeclForInstantiation(Shadow))
    PrevDecl = cast_or_null<UsingShadowDecl>(SemaRef.FindInstantiatedDecl(
        Shadow->getLocation(), OldPrev, TemplateArgs));

  UsingShadowDecl *InstShadow = SemaRef.BuildUsingShadowDecl(
      /*Scope*/ nullptr, Inst, InstTarget, PrevDecl);
  SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);

  if (isFunctionScope)
    SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);
}

return Inst;
3106}

3108Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {

// The nested name specifier may be dependent, for example
//     template <typename T> struct t {
//       struct s1 { T f1(); };
//       struct s2 : s1 { using s1::f1; };
//     };
//     template struct t<int>;
// Here, in using s1::f1, s1 refers to t<T>::s1;
// we need to substitute for t<int>::s1.
NestedNameSpecifierLoc QualifierLoc
  = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
                                        TemplateArgs);
if (!QualifierLoc)
  return nullptr;

// For an inheriting constructor declaration, the name of the using
// declaration is the name of a constructor in this class, not in the
// base class.
DeclarationNameInfo NameInfo = D->getNameInfo();
if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName)
  if (auto *RD = dyn_cast<CXXRecordDecl>(SemaRef.CurContext))
    NameInfo.setName(SemaRef.Context.DeclarationNames.getCXXConstructorName(
        SemaRef.Context.getCanonicalType(SemaRef.Context.getRecordType(RD))));

// We only need to do redeclaration lookups if we're in a class scope (in
// fact, it's not really even possible in non-class scopes).
bool CheckRedeclaration = Owner->isRecord();
LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,
                  Sema::ForVisibleRedeclaration);

UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,
                                     D->getUsingLoc(),
                                     QualifierLoc,
                                     NameInfo,
                                     D->hasTypename());

CXXScopeSpec SS;
SS.Adopt(QualifierLoc);
if (CheckRedeclaration) {
  Prev.setHideTags(false);
  SemaRef.LookupQualifiedName(Prev, Owner);

  // Check for invalid redeclarations.
  if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLoc(),
                                          D->hasTypename(), SS,
                                          D->getLocation(), Prev))
    NewUD->setInvalidDecl();
}

if (!NewUD->isInvalidDecl() &&
    SemaRef.CheckUsingDeclQualifier(D->getUsingLoc(), D->hasTypename(), SS,
                                    NameInfo, D->getLocation(), nullptr, D))
  NewUD->setInvalidDecl();

SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);
NewUD->setAccess(D->getAccess());
Owner->addDecl(NewUD);

// Don't process the shadow decls for an invalid decl.
if (NewUD->isInvalidDecl())
  return NewUD;

// If the using scope was dependent, or we had dependent bases, we need to
// recheck the inheritance
if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName)
  SemaRef.CheckInheritingConstructorUsingDecl(NewUD);

return VisitBaseUsingDecls(D, NewUD, CheckRedeclaration ? &Prev : nullptr);
3177}

3179Decl *TemplateDeclInstantiator::VisitUsingEnumDecl(UsingEnumDecl *D) {
// Cannot be a dependent type, but still could be an instantiation
EnumDecl *EnumD = cast_or_null<EnumDecl>(SemaRef.FindInstantiatedDecl(
    D->getLocation(), D->getEnumDecl(), TemplateArgs));

if (SemaRef.RequireCompleteEnumDecl(EnumD, EnumD->getLocation()))
  return nullptr;

UsingEnumDecl *NewUD =
    UsingEnumDecl::Create(SemaRef.Context, Owner, D->getUsingLoc(),
                          D->getEnumLoc(), D->getLocation(), EnumD);

SemaRef.Context.setInstantiatedFromUsingEnumDecl(NewUD, D);
NewUD->setAccess(D->getAccess());
Owner->addDecl(NewUD);

// Don't process the shadow decls for an invalid decl.
if (NewUD->isInvalidDecl())
  return NewUD;

// We don't have to recheck for duplication of the UsingEnumDecl itself, as it
// cannot be dependent, and will therefore have been checked during template
// definition.

return VisitBaseUsingDecls(D, NewUD, nullptr);
3204}

3206Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {
// Ignore these;  we handle them in bulk when processing the UsingDecl.
return nullptr;
3209}

3211Decl *TemplateDeclInstantiator::VisitConstructorUsingShadowDecl(
  ConstructorUsingShadowDecl *D) {
// Ignore these;  we handle them in bulk when processing the UsingDecl.
return nullptr;
3215}

3217template <typename T>
3218Decl *TemplateDeclInstantiator::instantiateUnresolvedUsingDecl(
  T *D, bool InstantiatingPackElement) {
// If this is a pack expansion, expand it now.
if (D->isPackExpansion() && !InstantiatingPackElement) {
  SmallVector<UnexpandedParameterPack, 2> Unexpanded;
  SemaRef.collectUnexpandedParameterPacks(D->getQualifierLoc(), Unexpanded);
  SemaRef.collectUnexpandedParameterPacks(D->getNameInfo(), Unexpanded);

  // Determine whether the set of unexpanded parameter packs can and should
  // be expanded.
  bool Expand = true;
  bool RetainExpansion = false;
  Optional<unsigned> NumExpansions;
  if (SemaRef.CheckParameterPacksForExpansion(
        D->getEllipsisLoc(), D->getSourceRange(), Unexpanded, TemplateArgs,
          Expand, RetainExpansion, NumExpansions))
    return nullptr;

  // This declaration cannot appear within a function template signature,
  // so we can't have a partial argument list for a parameter pack.
  assert(!RetainExpansion &&((void)0)
         "should never need to retain an expansion for UsingPackDecl")((void)0);

  if (!Expand) {
    // We cannot fully expand the pack expansion now, so substitute into the
    // pattern and create a new pack expansion.
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
    return instantiateUnresolvedUsingDecl(D, true);
  }

  // Within a function, we don't have any normal way to check for conflicts
  // between shadow declarations from different using declarations in the
  // same pack expansion, but this is always ill-formed because all expansions
  // must produce (conflicting) enumerators.
  //
  // Sadly we can't just reject this in the template definition because it
  // could be valid if the pack is empty or has exactly one expansion.
  if (D->getDeclContext()->isFunctionOrMethod() && *NumExpansions > 1) {
    SemaRef.Diag(D->getEllipsisLoc(),
                 diag::err_using_decl_redeclaration_expansion);
    return nullptr;
  }

  // Instantiate the slices of this pack and build a UsingPackDecl.
  SmallVector<NamedDecl*, 8> Expansions;
  for (unsigned I = 0; I != *NumExpansions; ++I) {
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
    Decl *Slice = instantiateUnresolvedUsingDecl(D, true);
    if (!Slice)
      return nullptr;
    // Note that we can still get unresolved using declarations here, if we
    // had arguments for all packs but the pattern also contained other
    // template arguments (this only happens during partial substitution, eg
    // into the body of a generic lambda in a function template).
    Expansions.push_back(cast<NamedDecl>(Slice));
  }

  auto *NewD = SemaRef.BuildUsingPackDecl(D, Expansions);
  if (isDeclWithinFunction(D))
    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewD);
  return NewD;
}

UnresolvedUsingTypenameDecl *TD = dyn_cast<UnresolvedUsingTypenameDecl>(D);
SourceLocation TypenameLoc = TD ? TD->getTypenameLoc() : SourceLocation();

NestedNameSpecifierLoc QualifierLoc
  = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),
                                        TemplateArgs);
if (!QualifierLoc)
  return nullptr;

CXXScopeSpec SS;
SS.Adopt(QualifierLoc);

DeclarationNameInfo NameInfo
  = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);

// Produce a pack expansion only if we're not instantiating a particular
// slice of a pack expansion.
bool InstantiatingSlice = D->getEllipsisLoc().isValid() &&
                          SemaRef.ArgumentPackSubstitutionIndex != -1;
SourceLocation EllipsisLoc =
    InstantiatingSlice ? SourceLocation() : D->getEllipsisLoc();

bool IsUsingIfExists = D->template hasAttr<UsingIfExistsAttr>();
NamedDecl *UD = SemaRef.BuildUsingDeclaration(
    /*Scope*/ nullptr, D->getAccess(), D->getUsingLoc(),
    /*HasTypename*/ TD, TypenameLoc, SS, NameInfo, EllipsisLoc,
    ParsedAttributesView(),
    /*IsInstantiation*/ true, IsUsingIfExists);
if (UD) {
  SemaRef.InstantiateAttrs(TemplateArgs, D, UD);
  SemaRef.Context.setInstantiatedFromUsingDecl(UD, D);
}

return UD;
3315}

3317Decl *TemplateDeclInstantiator::VisitUnresolvedUsingTypenameDecl(
  UnresolvedUsingTypenameDecl *D) {
return instantiateUnresolvedUsingDecl(D);
3320}

3322Decl *TemplateDeclInstantiator::VisitUnresolvedUsingValueDecl(
  UnresolvedUsingValueDecl *D) {
return instantiateUnresolvedUsingDecl(D);
3325}

3327Decl *TemplateDeclInstantiator::VisitUnresolvedUsingIfExistsDecl(
  UnresolvedUsingIfExistsDecl *D) {
llvm_unreachable("referring to unresolved decl out of UsingShadowDecl")__builtin_unreachable();
3330}

3332Decl *TemplateDeclInstantiator::VisitUsingPackDecl(UsingPackDecl *D) {
SmallVector<NamedDecl*, 8> Expansions;
for (auto *UD : D->expansions()) {
  if (NamedDecl *NewUD =
          SemaRef.FindInstantiatedDecl(D->getLocation(), UD, TemplateArgs))
    Expansions.push_back(NewUD);
  else
    return nullptr;
}

auto *NewD = SemaRef.BuildUsingPackDecl(D, Expansions);
if (isDeclWithinFunction(D))
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewD);
return NewD;
3346}

3348Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
  ClassScopeFunctionSpecializationDecl *Decl) {
CXXMethodDecl *OldFD = Decl->getSpecialization();
return cast_or_null<CXXMethodDecl>(
    VisitCXXMethodDecl(OldFD, nullptr, Decl->getTemplateArgsAsWritten()));
3353}

3355Decl *TemplateDeclInstantiator::VisitOMPThreadPrivateDecl(
                                   OMPThreadPrivateDecl *D) {
SmallVector<Expr *, 5> Vars;
for (auto *I : D->varlists()) {
  Expr *Var = SemaRef.SubstExpr(I, TemplateArgs).get();
  assert(isa<DeclRefExpr>(Var) && "threadprivate arg is not a DeclRefExpr")((void)0);
  Vars.push_back(Var);
}

OMPThreadPrivateDecl *TD =
  SemaRef.CheckOMPThreadPrivateDecl(D->getLocation(), Vars);

TD->setAccess(AS_public);
Owner->addDecl(TD);

return TD;
3371}

3373Decl *TemplateDeclInstantiator::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
SmallVector<Expr *, 5> Vars;
for (auto *I : D->varlists()) {
  Expr *Var = SemaRef.SubstExpr(I, TemplateArgs).get();
  assert(isa<DeclRefExpr>(Var) && "allocate arg is not a DeclRefExpr")((void)0);
  Vars.push_back(Var);
}
SmallVector<OMPClause *, 4> Clauses;
// Copy map clauses from the original mapper.
for (OMPClause *C : D->clauselists()) {
  auto *AC = cast<OMPAllocatorClause>(C);
  ExprResult NewE = SemaRef.SubstExpr(AC->getAllocator(), TemplateArgs);
  if (!NewE.isUsable())
    continue;
  OMPClause *IC = SemaRef.ActOnOpenMPAllocatorClause(
      NewE.get(), AC->getBeginLoc(), AC->getLParenLoc(), AC->getEndLoc());
  Clauses.push_back(IC);
}

Sema::DeclGroupPtrTy Res = SemaRef.ActOnOpenMPAllocateDirective(
    D->getLocation(), Vars, Clauses, Owner);
if (Res.get().isNull())
  return nullptr;
return Res.get().getSingleDecl();
3397}

3399Decl *TemplateDeclInstantiator::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
llvm_unreachable(__builtin_unreachable()
    "Requires directive cannot be instantiated within a dependent context")__builtin_unreachable();
3402}

3404Decl *TemplateDeclInstantiator::VisitOMPDeclareReductionDecl(
  OMPDeclareReductionDecl *D) {
// Instantiate type and check if it is allowed.
const bool RequiresInstantiation =
    D->getType()->isDependentType() ||
    D->getType()->isInstantiationDependentType() ||
    D->getType()->containsUnexpandedParameterPack();
QualType SubstReductionType;
if (RequiresInstantiation) {
  SubstReductionType = SemaRef.ActOnOpenMPDeclareReductionType(
      D->getLocation(),
      ParsedType::make(SemaRef.SubstType(
          D->getType(), TemplateArgs, D->getLocation(), DeclarationName())));
} else {
  SubstReductionType = D->getType();
}
if (SubstReductionType.isNull())
  return nullptr;
Expr *Combiner = D->getCombiner();
Expr *Init = D->getInitializer();
bool IsCorrect = true;
// Create instantiated copy.
std::pair<QualType, SourceLocation> ReductionTypes[] = {
    std::make_pair(SubstReductionType, D->getLocation())};
auto *PrevDeclInScope = D->getPrevDeclInScope();
if (PrevDeclInScope && !PrevDeclInScope->isInvalidDecl()) {
  PrevDeclInScope = cast<OMPDeclareReductionDecl>(
      SemaRef.CurrentInstantiationScope->findInstantiationOf(PrevDeclInScope)
          ->get<Decl *>());
}
auto DRD = SemaRef.ActOnOpenMPDeclareReductionDirectiveStart(
    /*S=*/nullptr, Owner, D->getDeclName(), ReductionTypes, D->getAccess(),
    PrevDeclInScope);
auto *NewDRD = cast<OMPDeclareReductionDecl>(DRD.get().getSingleDecl());
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewDRD);
Expr *SubstCombiner = nullptr;
Expr *SubstInitializer = nullptr;
// Combiners instantiation sequence.
if (Combiner) {
  SemaRef.ActOnOpenMPDeclareReductionCombinerStart(
      /*S=*/nullptr, NewDRD);
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(
      cast<DeclRefExpr>(D->getCombinerIn())->getDecl(),
      cast<DeclRefExpr>(NewDRD->getCombinerIn())->getDecl());
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(
      cast<DeclRefExpr>(D->getCombinerOut())->getDecl(),
      cast<DeclRefExpr>(NewDRD->getCombinerOut())->getDecl());
  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);
  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, Qualifiers(),
                                   ThisContext);
  SubstCombiner = SemaRef.SubstExpr(Combiner, TemplateArgs).get();
  SemaRef.ActOnOpenMPDeclareReductionCombinerEnd(NewDRD, SubstCombiner);
}
// Initializers instantiation sequence.
if (Init) {
  VarDecl *OmpPrivParm = SemaRef.ActOnOpenMPDeclareReductionInitializerStart(
      /*S=*/nullptr, NewDRD);
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(
      cast<DeclRefExpr>(D->getInitOrig())->getDecl(),
      cast<DeclRefExpr>(NewDRD->getInitOrig())->getDecl());
  SemaRef.CurrentInstantiationScope->InstantiatedLocal(
      cast<DeclRefExpr>(D->getInitPriv())->getDecl(),
      cast<DeclRefExpr>(NewDRD->getInitPriv())->getDecl());
  if (D->getInitializerKind() == OMPDeclareReductionDecl::CallInit) {
    SubstInitializer = SemaRef.SubstExpr(Init, TemplateArgs).get();
  } else {
    auto *OldPrivParm =
        cast<VarDecl>(cast<DeclRefExpr>(D->getInitPriv())->getDecl());
    IsCorrect = IsCorrect && OldPrivParm->hasInit();
    if (IsCorrect)
      SemaRef.InstantiateVariableInitializer(OmpPrivParm, OldPrivParm,
                                             TemplateArgs);
  }
  SemaRef.ActOnOpenMPDeclareReductionInitializerEnd(NewDRD, SubstInitializer,
                                                    OmpPrivParm);
}
IsCorrect = IsCorrect && SubstCombiner &&
            (!Init ||
             (D->getInitializerKind() == OMPDeclareReductionDecl::CallInit &&
              SubstInitializer) ||
             (D->getInitializerKind() != OMPDeclareReductionDecl::CallInit &&
              !SubstInitializer));

(void)SemaRef.ActOnOpenMPDeclareReductionDirectiveEnd(
    /*S=*/nullptr, DRD, IsCorrect && !D->isInvalidDecl());

return NewDRD;
3491}

3493Decl *
3494TemplateDeclInstantiator::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
// Instantiate type and check if it is allowed.
const bool RequiresInstantiation =
    D->getType()->isDependentType() ||
    D->getType()->isInstantiationDependentType() ||
    D->getType()->containsUnexpandedParameterPack();
QualType SubstMapperTy;
DeclarationName VN = D->getVarName();
if (RequiresInstantiation) {
  SubstMapperTy = SemaRef.ActOnOpenMPDeclareMapperType(
      D->getLocation(),
      ParsedType::make(SemaRef.SubstType(D->getType(), TemplateArgs,
                                         D->getLocation(), VN)));
} else {
  SubstMapperTy = D->getType();
}
if (SubstMapperTy.isNull())
  return nullptr;
// Create an instantiated copy of mapper.
auto *PrevDeclInScope = D->getPrevDeclInScope();
if (PrevDeclInScope && !PrevDeclInScope->isInvalidDecl()) {
  PrevDeclInScope = cast<OMPDeclareMapperDecl>(
      SemaRef.CurrentInstantiationScope->findInstantiationOf(PrevDeclInScope)
          ->get<Decl *>());
}
bool IsCorrect = true;
SmallVector<OMPClause *, 6> Clauses;
// Instantiate the mapper variable.
DeclarationNameInfo DirName;
SemaRef.StartOpenMPDSABlock(llvm::omp::OMPD_declare_mapper, DirName,
                            /*S=*/nullptr,
                            (*D->clauselist_begin())->getBeginLoc());
ExprResult MapperVarRef = SemaRef.ActOnOpenMPDeclareMapperDirectiveVarDecl(
    /*S=*/nullptr, SubstMapperTy, D->getLocation(), VN);
SemaRef.CurrentInstantiationScope->InstantiatedLocal(
    cast<DeclRefExpr>(D->getMapperVarRef())->getDecl(),
    cast<DeclRefExpr>(MapperVarRef.get())->getDecl());
auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);
Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, Qualifiers(),
                                 ThisContext);
// Instantiate map clauses.
for (OMPClause *C : D->clauselists()) {
  auto *OldC = cast<OMPMapClause>(C);
  SmallVector<Expr *, 4> NewVars;
  for (Expr *OE : OldC->varlists()) {
    Expr *NE = SemaRef.SubstExpr(OE, TemplateArgs).get();
    if (!NE) {
      IsCorrect = false;
      break;
    }
    NewVars.push_back(NE);
  }
  if (!IsCorrect)
    break;
  NestedNameSpecifierLoc NewQualifierLoc =
      SemaRef.SubstNestedNameSpecifierLoc(OldC->getMapperQualifierLoc(),
                                          TemplateArgs);
  CXXScopeSpec SS;
  SS.Adopt(NewQualifierLoc);
  DeclarationNameInfo NewNameInfo =
      SemaRef.SubstDeclarationNameInfo(OldC->getMapperIdInfo(), TemplateArgs);
  OMPVarListLocTy Locs(OldC->getBeginLoc(), OldC->getLParenLoc(),
                       OldC->getEndLoc());
  OMPClause *NewC = SemaRef.ActOnOpenMPMapClause(
      OldC->getMapTypeModifiers(), OldC->getMapTypeModifiersLoc(), SS,
      NewNameInfo, OldC->getMapType(), OldC->isImplicitMapType(),
      OldC->getMapLoc(), OldC->getColonLoc(), NewVars, Locs);
  Clauses.push_back(NewC);
}
SemaRef.EndOpenMPDSABlock(nullptr);
if (!IsCorrect)
  return nullptr;
Sema::DeclGroupPtrTy DG = SemaRef.ActOnOpenMPDeclareMapperDirective(
    /*S=*/nullptr, Owner, D->getDeclName(), SubstMapperTy, D->getLocation(),
    VN, D->getAccess(), MapperVarRef.get(), Clauses, PrevDeclInScope);
Decl *NewDMD = DG.get().getSingleDecl();
SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewDMD);
return NewDMD;
3572}

3574Decl *TemplateDeclInstantiator::VisitOMPCapturedExprDecl(
  OMPCapturedExprDecl * /*D*/) {
llvm_unreachable("Should not be met in templates")__builtin_unreachable();
3577}

3579Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {
return VisitFunctionDecl(D, nullptr);
3581}

3583Decl *
3584TemplateDeclInstantiator::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
Decl *Inst = VisitFunctionDecl(D, nullptr);
if (Inst && !D->getDescribedFunctionTemplate())
  Owner->addDecl(Inst);
return Inst;
3589}

3591Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {
return VisitCXXMethodDecl(D, nullptr);
3593}

3595Decl *TemplateDeclInstantiator::VisitRecordDecl(RecordDecl *D) {
llvm_unreachable("There are only CXXRecordDecls in C++")__builtin_unreachable();
3597}

3599Decl *
3600TemplateDeclInstantiator::VisitClassTemplateSpecializationDecl(
  ClassTemplateSpecializationDecl *D) {
// As a MS extension, we permit class-scope explicit specialization
// of member class templates.
ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();
assert(ClassTemplate->getDeclContext()->isRecord() &&((void)0)
       D->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&((void)0)
       "can only instantiate an explicit specialization "((void)0)
       "for a member class template")((void)0);

// Lookup the already-instantiated declaration in the instantiation
// of the class template.
ClassTemplateDecl *InstClassTemplate =
    cast_or_null<ClassTemplateDecl>(SemaRef.FindInstantiatedDecl(
        D->getLocation(), ClassTemplate, TemplateArgs));
if (!InstClassTemplate)
  return nullptr;

// Substitute into the template arguments of the class template explicit
// specialization.
TemplateSpecializationTypeLoc Loc = D->getTypeAsWritten()->getTypeLoc().
                                      castAs<TemplateSpecializationTypeLoc>();
TemplateArgumentListInfo InstTemplateArgs(Loc.getLAngleLoc(),
                                          Loc.getRAngleLoc());
SmallVector<TemplateArgumentLoc, 4> ArgLocs;
for (unsigned I = 0; I != Loc.getNumArgs(); ++I)
  ArgLocs.push_back(Loc.getArgLoc(I));
if (SemaRef.Subst(ArgLocs.data(), ArgLocs.size(),
                  InstTemplateArgs, TemplateArgs))
  return nullptr;

// Check that the template argument list is well-formed for this
// class template.
SmallVector<TemplateArgument, 4> Converted;
if (SemaRef.CheckTemplateArgumentList(InstClassTemplate,
                                      D->getLocation(),
                                      InstTemplateArgs,
                                      false,
                                      Converted,
                                      /*UpdateArgsWithConversion=*/true))
  return nullptr;

// Figure out where to insert this class template explicit specialization
// in the member template's set of class template explicit specializations.
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *PrevDecl =
    InstClassTemplate->findSpecialization(Converted, InsertPos);

// Check whether we've already seen a conflicting instantiation of this
// declaration (for instance, if there was a prior implicit instantiation).
bool Ignored;
if (PrevDecl &&
    SemaRef.CheckSpecializationInstantiationRedecl(D->getLocation(),
                                                   D->getSpecializationKind(),
                                                   PrevDecl,
                                                   PrevDecl->getSpecializationKind(),
                                                   PrevDecl->getPointOfInstantiation(),
                                                   Ignored))
  return nullptr;

// If PrevDecl was a definition and D is also a definition, diagnose.
// This happens in cases like:
//
//   template<typename T, typename U>
//   struct Outer {
//     template<typename X> struct Inner;
//     template<> struct Inner<T> {};
//     template<> struct Inner<U> {};
//   };
//
//   Outer<int, int> outer; // error: the explicit specializations of Inner
//                          // have the same signature.
if (PrevDecl && PrevDecl->getDefinition() &&
    D->isThisDeclarationADefinition()) {
  SemaRef.Diag(D->getLocation(), diag::err_redefinition) << PrevDecl;
  SemaRef.Diag(PrevDecl->getDefinition()->getLocation(),
               diag::note_previous_definition);
  return nullptr;
}

// Create the class template partial specialization declaration.
ClassTemplateSpecializationDecl *InstD =
    ClassTemplateSpecializationDecl::Create(
        SemaRef.Context, D->getTagKind(), Owner, D->getBeginLoc(),
        D->getLocation(), InstClassTemplate, Converted, PrevDecl);

// Add this partial specialization to the set of class template partial
// specializations.
if (!PrevDecl)
  InstClassTemplate->AddSpecialization(InstD, InsertPos);

// Substitute the nested name specifier, if any.
if (SubstQualifier(D, InstD))
  return nullptr;

// Build the canonical type that describes the converted template
// arguments of the class template explicit specialization.
QualType CanonType = SemaRef.Context.getTemplateSpecializationType(
    TemplateName(InstClassTemplate), Converted,
    SemaRef.Context.getRecordType(InstD));

// Build the fully-sugared type for this class template
// specialization as the user wrote in the specialization
// itself. This means that we'll pretty-print the type retrieved
// from the specialization's declaration the way that the user
// actually wrote the specialization, rather than formatting the
// name based on the "canonical" representation used to store the
// template arguments in the specialization.
TypeSourceInfo *WrittenTy = SemaRef.Context.getTemplateSpecializationTypeInfo(
    TemplateName(InstClassTemplate), D->getLocation(), InstTemplateArgs,
    CanonType);

InstD->setAccess(D->getAccess());
InstD->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);
InstD->setSpecializationKind(D->getSpecializationKind());
InstD->setTypeAsWritten(WrittenTy);
InstD->setExternLoc(D->getExternLoc());
InstD->setTemplateKeywordLoc(D->getTemplateKeywordLoc());

Owner->addDecl(InstD);

// Instantiate the members of the class-scope explicit specialization eagerly.
// We don't have support for lazy instantiation of an explicit specialization
// yet, and MSVC eagerly instantiates in this case.
// FIXME: This is wrong in standard C++.
if (D->isThisDeclarationADefinition() &&
    SemaRef.InstantiateClass(D->getLocation(), InstD, D, TemplateArgs,
                             TSK_ImplicitInstantiation,
                             /*Complain=*/true))
  return nullptr;

return InstD;
3732}

3734Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(
  VarTemplateSpecializationDecl *D) {

TemplateArgumentListInfo VarTemplateArgsInfo;
VarTemplateDecl *VarTemplate = D->getSpecializedTemplate();
assert(VarTemplate &&((void)0)
       "A template specialization without specialized template?")((void)0);

VarTemplateDecl *InstVarTemplate =
    cast_or_null<VarTemplateDecl>(SemaRef.FindInstantiatedDecl(
        D->getLocation(), VarTemplate, TemplateArgs));
if (!InstVarTemplate)
  return nullptr;

// Substitute the current template arguments.
const TemplateArgumentListInfo &TemplateArgsInfo = D->getTemplateArgsInfo();
VarTemplateArgsInfo.setLAngleLoc(TemplateArgsInfo.getLAngleLoc());
VarTemplateArgsInfo.setRAngleLoc(TemplateArgsInfo.getRAngleLoc());

if (SemaRef.Subst(TemplateArgsInfo.getArgumentArray(),
                  TemplateArgsInfo.size(), VarTemplateArgsInfo, TemplateArgs))
  return nullptr;

// Check that the template argument list is well-formed for this template.
SmallVector<TemplateArgument, 4> Converted;
if (SemaRef.CheckTemplateArgumentList(InstVarTemplate, D->getLocation(),
                                      VarTemplateArgsInfo, false, Converted,
                                      /*UpdateArgsWithConversion=*/true))
  return nullptr;

// Check whether we've already seen a declaration of this specialization.
void *InsertPos = nullptr;
VarTemplateSpecializationDecl *PrevDecl =
    InstVarTemplate->findSpecialization(Converted, InsertPos);

// Check whether we've already seen a conflicting instantiation of this
// declaration (for instance, if there was a prior implicit instantiation).
bool Ignored;
if (PrevDecl && SemaRef.CheckSpecializationInstantiationRedecl(
                    D->getLocation(), D->getSpecializationKind(), PrevDecl,
                    PrevDecl->getSpecializationKind(),
                    PrevDecl->getPointOfInstantiation(), Ignored))
  return nullptr;

return VisitVarTemplateSpecializationDecl(
    InstVarTemplate, D, VarTemplateArgsInfo, Converted, PrevDecl);
3780}

3782Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(
  VarTemplateDecl *VarTemplate, VarDecl *D,
  const TemplateArgumentListInfo &TemplateArgsInfo,
  ArrayRef<TemplateArgument> Converted,
  VarTemplateSpecializationDecl *PrevDecl) {

// Do substitution on the type of the declaration
TypeSourceInfo *DI =
    SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,
                      D->getTypeSpecStartLoc(), D->getDeclName());
if (!DI)
  return nullptr;

if (DI->getType()->isFunctionType()) {
  SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)
      << D->isStaticDataMember() << DI->getType();
  return nullptr;
}

// Build the instantiated declaration
VarTemplateSpecializationDecl *Var = VarTemplateSpecializationDecl::Create(
    SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),
    VarTemplate, DI->getType(), DI, D->getStorageClass(), Converted);
Var->setTemplateArgsInfo(TemplateArgsInfo);
if (!PrevDecl) {
  void *InsertPos = nullptr;
  VarTemplate->findSpecialization(Converted, InsertPos);
  VarTemplate->AddSpecialization(Var, InsertPos);
}

if (SemaRef.getLangOpts().OpenCL)
  SemaRef.deduceOpenCLAddressSpace(Var);

// Substitute the nested name specifier, if any.
if (SubstQualifier(D, Var))
  return nullptr;

SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,
                                   StartingScope, false, PrevDecl);

return Var;
3823}

3825Decl *TemplateDeclInstantiator::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
llvm_unreachable("@defs is not supported in Objective-C++")__builtin_unreachable();
3827}

3829Decl *TemplateDeclInstantiator::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
// FIXME: We need to be able to instantiate FriendTemplateDecls.
unsigned DiagID = SemaRef.getDiagnostics().getCustomDiagID(
                                             DiagnosticsEngine::Error,
                                             "cannot instantiate %0 yet");
SemaRef.Diag(D->getLocation(), DiagID)
  << D->getDeclKindName();

return nullptr;
3838}

3840Decl *TemplateDeclInstantiator::VisitConceptDecl(ConceptDecl *D) {
llvm_unreachable("Concept definitions cannot reside inside a template")__builtin_unreachable();
3842}

3844Decl *
3845TemplateDeclInstantiator::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
return RequiresExprBodyDecl::Create(SemaRef.Context, D->getDeclContext(),
                                    D->getBeginLoc());
3848}

3850Decl *TemplateDeclInstantiator::VisitDecl(Decl *D) {
llvm_unreachable("Unexpected decl")__builtin_unreachable();
3852}

3854Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
                    const MultiLevelTemplateArgumentList &TemplateArgs) {
TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
if (D->isInvalidDecl())
  return nullptr;

Decl *SubstD;
runWithSufficientStackSpace(D->getLocation(), [&] {
  SubstD = Instantiator.Visit(D);
});
return SubstD;
3865}

3867void TemplateDeclInstantiator::adjustForRewrite(RewriteKind RK,
                                              FunctionDecl *Orig, QualType &T,
                                              TypeSourceInfo *&TInfo,
                                              DeclarationNameInfo &NameInfo) {
assert(RK == RewriteKind::RewriteSpaceshipAsEqualEqual)((void)0);

// C++2a [class.compare.default]p3:
//   the return type is replaced with bool
auto *FPT = T->castAs<FunctionProtoType>();
T = SemaRef.Context.getFunctionType(
    SemaRef.Context.BoolTy, FPT->getParamTypes(), FPT->getExtProtoInfo());

// Update the return type in the source info too. The most straightforward
// way is to create new TypeSourceInfo for the new type. Use the location of
// the '= default' as the location of the new type.
//
// FIXME: Set the correct return type when we initially transform the type,
// rather than delaying it to now.
TypeSourceInfo *NewTInfo =
    SemaRef.Context.getTrivialTypeSourceInfo(T, Orig->getEndLoc());
auto OldLoc = TInfo->getTypeLoc().getAsAdjusted<FunctionProtoTypeLoc>();
assert(OldLoc && "type of function is not a function type?")((void)0);
auto NewLoc = NewTInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>();
for (unsigned I = 0, N = OldLoc.getNumParams(); I != N; ++I)
  NewLoc.setParam(I, OldLoc.getParam(I));
TInfo = NewTInfo;

//   and the declarator-id is replaced with operator==
NameInfo.setName(
    SemaRef.Context.DeclarationNames.getCXXOperatorName(OO_EqualEqual));
3897}

3899FunctionDecl *Sema::SubstSpaceshipAsEqualEqual(CXXRecordDecl *RD,
                                             FunctionDecl *Spaceship) {
if (Spaceship->isInvalidDecl())
  return nullptr;

// C++2a [class.compare.default]p3:
//   an == operator function is declared implicitly [...] with the same
//   access and function-definition and in the same class scope as the
//   three-way comparison operator function
MultiLevelTemplateArgumentList NoTemplateArgs;
NoTemplateArgs.setKind(TemplateSubstitutionKind::Rewrite);
NoTemplateArgs.addOuterRetainedLevels(RD->getTemplateDepth());
TemplateDeclInstantiator Instantiator(*this, RD, NoTemplateArgs);
Decl *R;
if (auto *MD = dyn_cast<CXXMethodDecl>(Spaceship)) {
  R = Instantiator.VisitCXXMethodDecl(
      MD, nullptr, None,
      TemplateDeclInstantiator::RewriteKind::RewriteSpaceshipAsEqualEqual);
} else {
  assert(Spaceship->getFriendObjectKind() &&((void)0)
         "defaulted spaceship is neither a member nor a friend")((void)0);

  R = Instantiator.VisitFunctionDecl(
      Spaceship, nullptr,
      TemplateDeclInstantiator::RewriteKind::RewriteSpaceshipAsEqualEqual);
  if (!R)
    return nullptr;

  FriendDecl *FD =
      FriendDecl::Create(Context, RD, Spaceship->getLocation(),
                         cast<NamedDecl>(R), Spaceship->getBeginLoc());
  FD->setAccess(AS_public);
  RD->addDecl(FD);
}
return cast_or_null<FunctionDecl>(R);
3934}

3936/// Instantiates a nested template parameter list in the current
3937/// instantiation context.
3938///
3939/// \param L The parameter list to instantiate
3940///
3941/// \returns NULL if there was an error
3942TemplateParameterList *
3943TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {
// Get errors for all the parameters before bailing out.
bool Invalid = false;

unsigned N = L->size();
typedef SmallVector<NamedDecl *, 8> ParamVector;
ParamVector Params;
Params.reserve(N);
for (auto &P : *L) {
  NamedDecl *D = cast_or_null<NamedDecl>(Visit(P));
  Params.push_back(D);
  Invalid = Invalid || !D || D->isInvalidDecl();
}

// Clean up if we had an error.
if (Invalid)
  return nullptr;

// FIXME: Concepts: Substitution into requires clause should only happen when
// checking satisfaction.
Expr *InstRequiresClause = nullptr;
if (Expr *E = L->getRequiresClause()) {
  EnterExpressionEvaluationContext ConstantEvaluated(
      SemaRef, Sema::ExpressionEvaluationContext::Unevaluated);
  ExprResult Res = SemaRef.SubstExpr(E, TemplateArgs);
  if (Res.isInvalid() || !Res.isUsable()) {
    return nullptr;
  }
  InstRequiresClause = Res.get();
}

TemplateParameterList *InstL
  = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),
                                  L->getLAngleLoc(), Params,
                                  L->getRAngleLoc(), InstRequiresClause);
return InstL;
3979}

3981TemplateParameterList *
3982Sema::SubstTemplateParams(TemplateParameterList *Params, DeclContext *Owner,
                        const MultiLevelTemplateArgumentList &TemplateArgs) {
TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
return Instantiator.SubstTemplateParams(Params);
3986}

3988/// Instantiate the declaration of a class template partial
3989/// specialization.
3990///
3991/// \param ClassTemplate the (instantiated) class template that is partially
3992// specialized by the instantiation of \p PartialSpec.
3993///
3994/// \param PartialSpec the (uninstantiated) class template partial
3995/// specialization that we are instantiating.
3996///
3997/// \returns The instantiated partial specialization, if successful; otherwise,
3998/// NULL to indicate an error.
3999ClassTemplatePartialSpecializationDecl *
4000TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(
                                          ClassTemplateDecl *ClassTemplate,
                        ClassTemplatePartialSpecializationDecl *PartialSpec) {
// Create a local instantiation scope for this class template partial
// specialization, which will contain the instantiations of the template
// parameters.
LocalInstantiationScope Scope(SemaRef);

// Substitute into the template parameters of the class template partial
// specialization.
TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

// Substitute into the template arguments of the class template partial
// specialization.
const ASTTemplateArgumentListInfo *TemplArgInfo
  = PartialSpec->getTemplateArgsAsWritten();
TemplateArgumentListInfo InstTemplateArgs(TemplArgInfo->LAngleLoc,
                                          TemplArgInfo->RAngleLoc);
if (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
                  TemplArgInfo->NumTemplateArgs,
                  InstTemplateArgs, TemplateArgs))
  return nullptr;

// Check that the template argument list is well-formed for this
// class template.
SmallVector<TemplateArgument, 4> Converted;
if (SemaRef.CheckTemplateArgumentList(ClassTemplate,
                                      PartialSpec->getLocation(),
                                      InstTemplateArgs,
                                      false,
                                      Converted))
  return nullptr;

// Check these arguments are valid for a template partial specialization.
if (SemaRef.CheckTemplatePartialSpecializationArgs(
        PartialSpec->getLocation(), ClassTemplate, InstTemplateArgs.size(),
        Converted))
  return nullptr;

// Figure out where to insert this class template partial specialization
// in the member template's set of class template partial specializations.
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *PrevDecl
  = ClassTemplate->findPartialSpecialization(Converted, InstParams,
                                             InsertPos);

// Build the canonical type that describes the converted template
// arguments of the class template partial specialization.
QualType CanonType
  = SemaRef.Context.getTemplateSpecializationType(TemplateName(ClassTemplate),
                                                  Converted);

// Build the fully-sugared type for this class template
// specialization as the user wrote in the specialization
// itself. This means that we'll pretty-print the type retrieved
// from the specialization's declaration the way that the user
// actually wrote the specialization, rather than formatting the
// name based on the "canonical" representation used to store the
// template arguments in the specialization.
TypeSourceInfo *WrittenTy
  = SemaRef.Context.getTemplateSpecializationTypeInfo(
                                                  TemplateName(ClassTemplate),
                                                  PartialSpec->getLocation(),
                                                  InstTemplateArgs,
                                                  CanonType);

if (PrevDecl) {
  // We've already seen a partial specialization with the same template
  // parameters and template arguments. This can happen, for example, when
  // substituting the outer template arguments ends up causing two
  // class template partial specializations of a member class template
  // to have identical forms, e.g.,
  //
  //   template<typename T, typename U>
  //   struct Outer {
  //     template<typename X, typename Y> struct Inner;
  //     template<typename Y> struct Inner<T, Y>;
  //     template<typename Y> struct Inner<U, Y>;
  //   };
  //
  //   Outer<int, int> outer; // error: the partial specializations of Inner
  //                          // have the same signature.
  SemaRef.Diag(PartialSpec->getLocation(), diag::err_partial_spec_redeclared)
    << WrittenTy->getType();
  SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)
    << SemaRef.Context.getTypeDeclType(PrevDecl);
  return nullptr;
}


// Create the class template partial specialization declaration.
ClassTemplatePartialSpecializationDecl *InstPartialSpec =
    ClassTemplatePartialSpecializationDecl::Create(
        SemaRef.Context, PartialSpec->getTagKind(), Owner,
        PartialSpec->getBeginLoc(), PartialSpec->getLocation(), InstParams,
        ClassTemplate, Converted, InstTemplateArgs, CanonType, nullptr);
// Substitute the nested name specifier, if any.
if (SubstQualifier(PartialSpec, InstPartialSpec))
  return nullptr;

InstPartialSpec->setInstantiatedFromMember(PartialSpec);
InstPartialSpec->setTypeAsWritten(WrittenTy);

// Check the completed partial specialization.
SemaRef.CheckTemplatePartialSpecialization(InstPartialSpec);

// Add this partial specialization to the set of class template partial
// specializations.
ClassTemplate->AddPartialSpecialization(InstPartialSpec,
                                        /*InsertPos=*/nullptr);
return InstPartialSpec;
4114}

4116/// Instantiate the declaration of a variable template partial
4117/// specialization.
4118///
4119/// \param VarTemplate the (instantiated) variable template that is partially
4120/// specialized by the instantiation of \p PartialSpec.
4121///
4122/// \param PartialSpec the (uninstantiated) variable template partial
4123/// specialization that we are instantiating.
4124///
4125/// \returns The instantiated partial specialization, if successful; otherwise,
4126/// NULL to indicate an error.
4127VarTemplatePartialSpecializationDecl *
4128TemplateDeclInstantiator::InstantiateVarTemplatePartialSpecialization(
  VarTemplateDecl *VarTemplate,
  VarTemplatePartialSpecializationDecl *PartialSpec) {
// Create a local instantiation scope for this variable template partial
// specialization, which will contain the instantiations of the template
// parameters.
LocalInstantiationScope Scope(SemaRef);

// Substitute into the template parameters of the variable template partial
// specialization.
TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();
TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
if (!InstParams)
  return nullptr;

// Substitute into the template arguments of the variable template partial
// specialization.
const ASTTemplateArgumentListInfo *TemplArgInfo
  = PartialSpec->getTemplateArgsAsWritten();
TemplateArgumentListInfo InstTemplateArgs(TemplArgInfo->LAngleLoc,
                                          TemplArgInfo->RAngleLoc);
if (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
                  TemplArgInfo->NumTemplateArgs,
                  InstTemplateArgs, TemplateArgs))
  return nullptr;

// Check that the template argument list is well-formed for this
// class template.
SmallVector<TemplateArgument, 4> Converted;
if (SemaRef.CheckTemplateArgumentList(VarTemplate, PartialSpec->getLocation(),
                                      InstTemplateArgs, false, Converted))
  return nullptr;

// Check these arguments are valid for a template partial specialization.
if (SemaRef.CheckTemplatePartialSpecializationArgs(
        PartialSpec->getLocation(), VarTemplate, InstTemplateArgs.size(),
        Converted))
  return nullptr;

// Figure out where to insert this variable template partial specialization
// in the member template's set of variable template partial specializations.
void *InsertPos = nullptr;
VarTemplateSpecializationDecl *PrevDecl =
    VarTemplate->findPartialSpecialization(Converted, InstParams, InsertPos);

// Build the canonical type that describes the converted template
// arguments of the variable template partial specialization.
QualType CanonType = SemaRef.Context.getTemplateSpecializationType(
    TemplateName(VarTemplate), Converted);

// Build the fully-sugared type for this variable template
// specialization as the user wrote in the specialization
// itself. This means that we'll pretty-print the type retrieved
// from the specialization's declaration the way that the user
// actually wrote the specialization, rather than formatting the
// name based on the "canonical" representation used to store the
// template arguments in the specialization.
TypeSourceInfo *WrittenTy = SemaRef.Context.getTemplateSpecializationTypeInfo(
    TemplateName(VarTemplate), PartialSpec->getLocation(), InstTemplateArgs,
    CanonType);

if (PrevDecl) {
  // We've already seen a partial specialization with the same template
  // parameters and template arguments. This can happen, for example, when
  // substituting the outer template arguments ends up causing two
  // variable template partial specializations of a member variable template
  // to have identical forms, e.g.,
  //
  //   template<typename T, typename U>
  //   struct Outer {
  //     template<typename X, typename Y> pair<X,Y> p;
  //     template<typename Y> pair<T, Y> p;
  //     template<typename Y> pair<U, Y> p;
  //   };
  //
  //   Outer<int, int> outer; // error: the partial specializations of Inner
  //                          // have the same signature.
  SemaRef.Diag(PartialSpec->getLocation(),
               diag::err_var_partial_spec_redeclared)
      << WrittenTy->getType();
  SemaRef.Diag(PrevDecl->getLocation(),
               diag::note_var_prev_partial_spec_here);
  return nullptr;
}

// Do substitution on the type of the declaration
TypeSourceInfo *DI = SemaRef.SubstType(
    PartialSpec->getTypeSourceInfo(), TemplateArgs,
    PartialSpec->getTypeSpecStartLoc(), PartialSpec->getDeclName());
if (!DI)
  return nullptr;

if (DI->getType()->isFunctionType()) {
  SemaRef.Diag(PartialSpec->getLocation(),
               diag::err_variable_instantiates_to_function)
      << PartialSpec->isStaticDataMember() << DI->getType();
  return nullptr;
}

// Create the variable template partial specialization declaration.
VarTemplatePartialSpecializationDecl *InstPartialSpec =
    VarTemplatePartialSpecializationDecl::Create(
        SemaRef.Context, Owner, PartialSpec->getInnerLocStart(),
        PartialSpec->getLocation(), InstParams, VarTemplate, DI->getType(),
        DI, PartialSpec->getStorageClass(), Converted, InstTemplateArgs);

// Substitute the nested name specifier, if any.
if (SubstQualifier(PartialSpec, InstPartialSpec))
  return nullptr;

InstPartialSpec->setInstantiatedFromMember(PartialSpec);
InstPartialSpec->setTypeAsWritten(WrittenTy);

// Check the completed partial specialization.
SemaRef.CheckTemplatePartialSpecialization(InstPartialSpec);

// Add this partial specialization to the set of variable template partial
// specializations. The instantiation of the initializer is not necessary.
VarTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/nullptr);

SemaRef.BuildVariableInstantiation(InstPartialSpec, PartialSpec, TemplateArgs,
                                   LateAttrs, Owner, StartingScope);

return InstPartialSpec;
4252}

4254TypeSourceInfo*
4255TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
                            SmallVectorImpl<ParmVarDecl *> &Params) {
TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();
assert(OldTInfo && "substituting function without type source info")((void)0);
assert(Params.empty() && "parameter vector is non-empty at start")((void)0);

CXXRecordDecl *ThisContext = nullptr;
Qualifiers ThisTypeQuals;
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
  ThisContext = cast<CXXRecordDecl>(Owner);
  ThisTypeQuals = Method->getMethodQualifiers();
}

TypeSourceInfo *NewTInfo
  = SemaRef.SubstFunctionDeclType(OldTInfo, TemplateArgs,
                                  D->getTypeSpecStartLoc(),
                                  D->getDeclName(),
                                  ThisContext, ThisTypeQuals);
if (!NewTInfo)
  return nullptr;

TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();
if (FunctionProtoTypeLoc OldProtoLoc = OldTL.getAs<FunctionProtoTypeLoc>()) {
  if (NewTInfo != OldTInfo) {
    // Get parameters from the new type info.
    TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();
    FunctionProtoTypeLoc NewProtoLoc = NewTL.castAs<FunctionProtoTypeLoc>();
    unsigned NewIdx = 0;
    for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc.getNumParams();
         OldIdx != NumOldParams; ++OldIdx) {
      ParmVarDecl *OldParam = OldProtoLoc.getParam(OldIdx);
      if (!OldParam)
        return nullptr;

      LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;

      Optional<unsigned> NumArgumentsInExpansion;
      if (OldParam->isParameterPack())
        NumArgumentsInExpansion =
            SemaRef.getNumArgumentsInExpansion(OldParam->getType(),
                                               TemplateArgs);
      if (!NumArgumentsInExpansion) {
        // Simple case: normal parameter, or a parameter pack that's
        // instantiated to a (still-dependent) parameter pack.
        ParmVarDecl *NewParam = NewProtoLoc.getParam(NewIdx++);
        Params.push_back(NewParam);
        Scope->InstantiatedLocal(OldParam, NewParam);
      } else {
        // Parameter pack expansion: make the instantiation an argument pack.
        Scope->MakeInstantiatedLocalArgPack(OldParam);
        for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {
          ParmVarDecl *NewParam = NewProtoLoc.getParam(NewIdx++);
          Params.push_back(NewParam);
          Scope->InstantiatedLocalPackArg(OldParam, NewParam);
        }
      }
    }
  } else {
    // The function type itself was not dependent and therefore no
    // substitution occurred. However, we still need to instantiate
    // the function parameters themselves.
    const FunctionProtoType *OldProto =
        cast<FunctionProtoType>(OldProtoLoc.getType());
    for (unsigned i = 0, i_end = OldProtoLoc.getNumParams(); i != i_end;
         ++i) {
      ParmVarDecl *OldParam = OldProtoLoc.getParam(i);
      if (!OldParam) {
        Params.push_back(SemaRef.BuildParmVarDeclForTypedef(
            D, D->getLocation(), OldProto->getParamType(i)));
        continue;
      }

      ParmVarDecl *Parm =
          cast_or_null<ParmVarDecl>(VisitParmVarDecl(OldParam));
      if (!Parm)
        return nullptr;
      Params.push_back(Parm);
    }
  }
} else {
  // If the type of this function, after ignoring parentheses, is not
  // *directly* a function type, then we're instantiating a function that
  // was declared via a typedef or with attributes, e.g.,
  //
  //   typedef int functype(int, int);
  //   functype func;
  //   int __cdecl meth(int, int);
  //
  // In this case, we'll just go instantiate the ParmVarDecls that we
  // synthesized in the method declaration.
  SmallVector<QualType, 4> ParamTypes;
  Sema::ExtParameterInfoBuilder ExtParamInfos;
  if (SemaRef.SubstParmTypes(D->getLocation(), D->parameters(), nullptr,
                             TemplateArgs, ParamTypes, &Params,
                             ExtParamInfos))
    return nullptr;
}

return NewTInfo;
4354}

4356/// Introduce the instantiated function parameters into the local
4357/// instantiation scope, and set the parameter names to those used
4358/// in the template.
4359static bool addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
                                           const FunctionDecl *PatternDecl,
                                           LocalInstantiationScope &Scope,
                         const MultiLevelTemplateArgumentList &TemplateArgs) {
unsigned FParamIdx = 0;
for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {
  const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);
  if (!PatternParam->isParameterPack()) {
    // Simple case: not a parameter pack.
    assert(FParamIdx < Function->getNumParams())((void)0);
    ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
    FunctionParam->setDeclName(PatternParam->getDeclName());
    // If the parameter's type is not dependent, update it to match the type
    // in the pattern. They can differ in top-level cv-qualifiers, and we want
    // the pattern's type here. If the type is dependent, they can't differ,
    // per core issue 1668. Substitute into the type from the pattern, in case
    // it's instantiation-dependent.
    // FIXME: Updating the type to work around this is at best fragile.
    if (!PatternDecl->getType()->isDependentType()) {
      QualType T = S.SubstType(PatternParam->getType(), TemplateArgs,
                               FunctionParam->getLocation(),
                               FunctionParam->getDeclName());
      if (T.isNull())
        return true;
      FunctionParam->setType(T);
    }

    Scope.InstantiatedLocal(PatternParam, FunctionParam);
    ++FParamIdx;
    continue;
  }

  // Expand the parameter pack.
  Scope.MakeInstantiatedLocalArgPack(PatternParam);
  Optional<unsigned> NumArgumentsInExpansion
    = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
  if (NumArgumentsInExpansion) {
    QualType PatternType =
        PatternParam->getType()->castAs<PackExpansionType>()->getPattern();
    for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
      FunctionParam->setDeclName(PatternParam->getDeclName());
      if (!PatternDecl->getType()->isDependentType()) {
        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, Arg);
        QualType T = S.SubstType(PatternType, TemplateArgs,
                                 FunctionParam->getLocation(),
                                 FunctionParam->getDeclName());
        if (T.isNull())
          return true;
        FunctionParam->setType(T);
      }

      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
      ++FParamIdx;
    }
  }
}

return false;
4418}

4420bool Sema::InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
                                    ParmVarDecl *Param) {
assert(Param->hasUninstantiatedDefaultArg())((void)0);
Expr *UninstExpr = Param->getUninstantiatedDefaultArg();

EnterExpressionEvaluationContext EvalContext(
    *this, ExpressionEvaluationContext::PotentiallyEvaluated, Param);

// Instantiate the expression.
//
// FIXME: Pass in a correct Pattern argument, otherwise
// getTemplateInstantiationArgs uses the lexical context of FD, e.g.
//
// template<typename T>
// struct A {
//   static int FooImpl();
//
//   template<typename Tp>
//   // bug: default argument A<T>::FooImpl() is evaluated with 2-level
//   // template argument list [[T], [Tp]], should be [[Tp]].
//   friend A<Tp> Foo(int a);
// };
//
// template<typename T>
// A<T> Foo(int a = A<T>::FooImpl());
MultiLevelTemplateArgumentList TemplateArgs
  = getTemplateInstantiationArgs(FD, nullptr, /*RelativeToPrimary=*/true);

InstantiatingTemplate Inst(*this, CallLoc, Param,
                           TemplateArgs.getInnermost());
if (Inst.isInvalid())
  return true;
if (Inst.isAlreadyInstantiating()) {
  Diag(Param->getBeginLoc(), diag::err_recursive_default_argument) << FD;
  Param->setInvalidDecl();
  return true;
}

ExprResult Result;
{
  // C++ [dcl.fct.default]p5:
  //   The names in the [default argument] expression are bound, and
  //   the semantic constraints are checked, at the point where the
  //   default argument expression appears.
  ContextRAII SavedContext(*this, FD);
  LocalInstantiationScope Local(*this);

  FunctionDecl *Pattern = FD->getTemplateInstantiationPattern(
      /*ForDefinition*/ false);
  if (addInstantiatedParametersToScope(*this, FD, Pattern, Local,
                                       TemplateArgs))
    return true;

  runWithSufficientStackSpace(CallLoc, [&] {
    Result = SubstInitializer(UninstExpr, TemplateArgs,
                              /*DirectInit*/false);
  });
}
if (Result.isInvalid())
  return true;

// Check the expression as an initializer for the parameter.
InitializedEntity Entity
  = InitializedEntity::InitializeParameter(Context, Param);
InitializationKind Kind = InitializationKind::CreateCopy(
    Param->getLocation(),
    /*FIXME:EqualLoc*/ UninstExpr->getBeginLoc());
Expr *ResultE = Result.getAs<Expr>();

InitializationSequence InitSeq(*this, Entity, Kind, ResultE);
Result = InitSeq.Perform(*this, Entity, Kind, ResultE);
if (Result.isInvalid())
  return true;

Result =
    ActOnFinishFullExpr(Result.getAs<Expr>(), Param->getOuterLocStart(),
                        /*DiscardedValue*/ false);
if (Result.isInvalid())
  return true;

// Remember the instantiated default argument.
Param->setDefaultArg(Result.getAs<Expr>());
if (ASTMutationListener *L = getASTMutationListener())
  L->DefaultArgumentInstantiated(Param);

return false;
4506}

4508void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
                                  FunctionDecl *Decl) {
const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
if (Proto->getExceptionSpecType() != EST_Uninstantiated)
  return;

InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
                           InstantiatingTemplate::ExceptionSpecification());
if (Inst.isInvalid()) {
  // We hit the instantiation depth limit. Clear the exception specification
  // so that our callers don't have to cope with EST_Uninstantiated.
  UpdateExceptionSpec(Decl, EST_None);
  return;
}
if (Inst.isAlreadyInstantiating()) {
  // This exception specification indirectly depends on itself. Reject.
  // FIXME: Corresponding rule in the standard?
  Diag(PointOfInstantiation, diag::err_exception_spec_cycle) << Decl;
  UpdateExceptionSpec(Decl, EST_None);
  return;
}

// Enter the scope of this instantiation. We don't use
// PushDeclContext because we don't have a scope.
Sema::ContextRAII savedContext(*this, Decl);
LocalInstantiationScope Scope(*this);

MultiLevelTemplateArgumentList TemplateArgs =
  getTemplateInstantiationArgs(Decl, nullptr, /*RelativeToPrimary*/true);

// FIXME: We can't use getTemplateInstantiationPattern(false) in general
// here, because for a non-defining friend declaration in a class template,
// we don't store enough information to map back to the friend declaration in
// the template.
FunctionDecl *Template = Proto->getExceptionSpecTemplate();
if (addInstantiatedParametersToScope(*this, Decl, Template, Scope,
                                     TemplateArgs)) {
  UpdateExceptionSpec(Decl, EST_None);
  return;
}

SubstExceptionSpec(Decl, Template->getType()->castAs<FunctionProtoType>(),
                   TemplateArgs);
4551}

4553bool Sema::CheckInstantiatedFunctionTemplateConstraints(
  SourceLocation PointOfInstantiation, FunctionDecl *Decl,
  ArrayRef<TemplateArgument> TemplateArgs,
  ConstraintSatisfaction &Satisfaction) {
// In most cases we're not going to have constraints, so check for that first.
FunctionTemplateDecl *Template = Decl->getPrimaryTemplate();
// Note - code synthesis context for the constraints check is created
// inside CheckConstraintsSatisfaction.
SmallVector<const Expr *, 3> TemplateAC;
Template->getAssociatedConstraints(TemplateAC);
if (TemplateAC.empty()) {
  Satisfaction.IsSatisfied = true;
  return false;
}

// Enter the scope of this instantiation. We don't use
// PushDeclContext because we don't have a scope.
Sema::ContextRAII savedContext(*this, Decl);
LocalInstantiationScope Scope(*this);

// If this is not an explicit specialization - we need to get the instantiated
// version of the template arguments and add them to scope for the
// substitution.
if (Decl->isTemplateInstantiation()) {
  InstantiatingTemplate Inst(*this, Decl->getPointOfInstantiation(),
      InstantiatingTemplate::ConstraintsCheck{}, Decl->getPrimaryTemplate(),
      TemplateArgs, SourceRange());
  if (Inst.isInvalid())
    return true;
  MultiLevelTemplateArgumentList MLTAL(
      *Decl->getTemplateSpecializationArgs());
  if (addInstantiatedParametersToScope(
          *this, Decl, Decl->getPrimaryTemplate()->getTemplatedDecl(),
          Scope, MLTAL))
    return true;
}
Qualifiers ThisQuals;
CXXRecordDecl *Record = nullptr;
if (auto *Method = dyn_cast<CXXMethodDecl>(Decl)) {
  ThisQuals = Method->getMethodQualifiers();
  Record = Method->getParent();
}
CXXThisScopeRAII ThisScope(*this, Record, ThisQuals, Record != nullptr);
return CheckConstraintSatisfaction(Template, TemplateAC, TemplateArgs,
                                   PointOfInstantiation, Satisfaction);
4598}

4600/// Initializes the common fields of an instantiation function
4601/// declaration (New) from the corresponding fields of its template (Tmpl).
4602///
4603/// \returns true if there was an error
4604bool
4605TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
                                                  FunctionDecl *Tmpl) {
New->setImplicit(Tmpl->isImplicit());

// Forward the mangling number from the template to the instantiated decl.
SemaRef.Context.setManglingNumber(New,
                                  SemaRef.Context.getManglingNumber(Tmpl));

// If we are performing substituting explicitly-specified template arguments
// or deduced template arguments into a function template and we reach this
// point, we are now past the point where SFINAE applies and have committed
// to keeping the new function template specialization. We therefore
// convert the active template instantiation for the function template
// into a template instantiation for this specific function template
// specialization, which is not a SFINAE context, so that we diagnose any
// further errors in the declaration itself.
//
// FIXME: This is a hack.
typedef Sema::CodeSynthesisContext ActiveInstType;
ActiveInstType &ActiveInst = SemaRef.CodeSynthesisContexts.back();
if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||
    ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {
  if (FunctionTemplateDecl *FunTmpl
        = dyn_cast<FunctionTemplateDecl>(ActiveInst.Entity)) {
    assert(FunTmpl->getTemplatedDecl() == Tmpl &&((void)0)
           "Deduction from the wrong function template?")((void)0);
    (void) FunTmpl;
    SemaRef.InstantiatingSpecializations.erase(
        {ActiveInst.Entity->getCanonicalDecl(), ActiveInst.Kind});
    atTemplateEnd(SemaRef.TemplateInstCallbacks, SemaRef, ActiveInst);
    ActiveInst.Kind = ActiveInstType::TemplateInstantiation;
    ActiveInst.Entity = New;
    atTemplateBegin(SemaRef.TemplateInstCallbacks, SemaRef, ActiveInst);
  }
}

const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
assert(Proto && "Function template without prototype?")((void)0);

if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
  FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();

  // DR1330: In C++11, defer instantiation of a non-trivial
  // exception specification.
  // DR1484: Local classes and their members are instantiated along with the
  // containing function.
  if (SemaRef.getLangOpts().CPlusPlus11 &&
      EPI.ExceptionSpec.Type != EST_None &&
      EPI.ExceptionSpec.Type != EST_DynamicNone &&
      EPI.ExceptionSpec.Type != EST_BasicNoexcept &&
      !Tmpl->isInLocalScopeForInstantiation()) {
    FunctionDecl *ExceptionSpecTemplate = Tmpl;
    if (EPI.ExceptionSpec.Type == EST_Uninstantiated)
      ExceptionSpecTemplate = EPI.ExceptionSpec.SourceTemplate;
    ExceptionSpecificationType NewEST = EST_Uninstantiated;
    if (EPI.ExceptionSpec.Type == EST_Unevaluated)
      NewEST = EST_Unevaluated;

    // Mark the function has having an uninstantiated exception specification.
    const FunctionProtoType *NewProto
      = New->getType()->getAs<FunctionProtoType>();
    assert(NewProto && "Template instantiation without function prototype?")((void)0);
    EPI = NewProto->getExtProtoInfo();
    EPI.ExceptionSpec.Type = NewEST;
    EPI.ExceptionSpec.SourceDecl = New;
    EPI.ExceptionSpec.SourceTemplate = ExceptionSpecTemplate;
    New->setType(SemaRef.Context.getFunctionType(
        NewProto->getReturnType(), NewProto->getParamTypes(), EPI));
  } else {
    Sema::ContextRAII SwitchContext(SemaRef, New);
    SemaRef.SubstExceptionSpec(New, Proto, TemplateArgs);
  }
}

// Get the definition. Leaves the variable unchanged if undefined.
const FunctionDecl *Definition = Tmpl;
Tmpl->isDefined(Definition);

SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,
                         LateAttrs, StartingScope);

return false;
4687}

4689/// Initializes common fields of an instantiated method
4690/// declaration (New) from the corresponding fields of its template
4691/// (Tmpl).
4692///
4693/// \returns true if there was an error
4694bool
4695TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,
                                                CXXMethodDecl *Tmpl) {
if (InitFunctionInstantiation(New, Tmpl))
  return true;

if (isa<CXXDestructorDecl>(New) && SemaRef.getLangOpts().CPlusPlus11)
  SemaRef.AdjustDestructorExceptionSpec(cast<CXXDestructorDecl>(New));

New->setAccess(Tmpl->getAccess());
if (Tmpl->isVirtualAsWritten())
  New->setVirtualAsWritten(true);

// FIXME: New needs a pointer to Tmpl
return false;
4709}

4711bool TemplateDeclInstantiator::SubstDefaultedFunction(FunctionDecl *New,
                                                    FunctionDecl *Tmpl) {
// Transfer across any unqualified lookups.
if (auto *DFI = Tmpl->getDefaultedFunctionInfo()) {
  SmallVector<DeclAccessPair, 32> Lookups;
  Lookups.reserve(DFI->getUnqualifiedLookups().size());
  bool AnyChanged = false;
  for (DeclAccessPair DA : DFI->getUnqualifiedLookups()) {
    NamedDecl *D = SemaRef.FindInstantiatedDecl(New->getLocation(),
                                                DA.getDecl(), TemplateArgs);
    if (!D)
      return true;
    AnyChanged |= (D != DA.getDecl());
    Lookups.push_back(DeclAccessPair::make(D, DA.getAccess()));
  }

  // It's unlikely that substitution will change any declarations. Don't
  // store an unnecessary copy in that case.
  New->setDefaultedFunctionInfo(
      AnyChanged ? FunctionDecl::DefaultedFunctionInfo::Create(
                       SemaRef.Context, Lookups)
                 : DFI);
}

SemaRef.SetDeclDefaulted(New, Tmpl->getLocation());
return false;
4737}

4739/// Instantiate (or find existing instantiation of) a function template with a
4740/// given set of template arguments.
4741///
4742/// Usually this should not be used, and template argument deduction should be
4743/// used in its place.
4744FunctionDecl *
4745Sema::InstantiateFunctionDeclaration(FunctionTemplateDecl *FTD,
                                   const TemplateArgumentList *Args,
                                   SourceLocation Loc) {
FunctionDecl *FD = FTD->getTemplatedDecl();

sema::TemplateDeductionInfo Info(Loc);
InstantiatingTemplate Inst(
    *this, Loc, FTD, Args->asArray(),
    CodeSynthesisContext::ExplicitTemplateArgumentSubstitution, Info);
if (Inst.isInvalid())
  return nullptr;

ContextRAII SavedContext(*this, FD);
MultiLevelTemplateArgumentList MArgs(*Args);

return cast_or_null<FunctionDecl>(SubstDecl(FD, FD->getParent(), MArgs));
4761}

4763/// Instantiate the definition of the given function from its
4764/// template.
4765///
4766/// \param PointOfInstantiation the point at which the instantiation was
4767/// required. Note that this is not precisely a "point of instantiation"
4768/// for the function, but it's close.
4769///
4770/// \param Function the already-instantiated declaration of a
4771/// function template specialization or member function of a class template
4772/// specialization.
4773///
4774/// \param Recursive if true, recursively instantiates any functions that
4775/// are required by this instantiation.
4776///
4777/// \param DefinitionRequired if true, then we are performing an explicit
4778/// instantiation where the body of the function is required. Complain if
4779/// there is no such body.
4780void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
                                       FunctionDecl *Function,
                                       bool Recursive,
                                       bool DefinitionRequired,
                                       bool AtEndOfTU) {
if (Function->isInvalidDecl() || isa<CXXDeductionGuideDecl>(Function))
2
←
Assuming the condition is false→
3
←
Assuming 'Function' is not a 'CXXDeductionGuideDecl'→
4
←
Taking false branch→
  return;

// Never instantiate an explicit specialization except if it is a class scope
// explicit specialization.
TemplateSpecializationKind TSK =
    Function->getTemplateSpecializationKindForInstantiation();
if (TSK == TSK_ExplicitSpecialization)
5
←
Assuming 'TSK' is not equal to TSK_ExplicitSpecialization→
6
←
Taking false branch→
  return;

// Don't instantiate a definition if we already have one.
const FunctionDecl *ExistingDefn = nullptr;
if (Function->isDefined(ExistingDefn,
7
←
Assuming the condition is false→
8
←
Taking false branch→
                        /*CheckForPendingFriendDefinition=*/true)) {
  if (ExistingDefn->isThisDeclarationADefinition())
    return;

  // If we're asked to instantiate a function whose body comes from an
  // instantiated friend declaration, attach the instantiated body to the
  // corresponding declaration of the function.
  assert(ExistingDefn->isThisDeclarationInstantiatedFromAFriendDefinition())((void)0);
  Function = const_cast<FunctionDecl*>(ExistingDefn);
}

// Find the function body that we'll be substituting.
const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
assert(PatternDecl && "instantiating a non-template")((void)0);

const FunctionDecl *PatternDef = PatternDecl->getDefinition();
Stmt *Pattern = nullptr;
if (PatternDef8.1
'PatternDef' is null
1
'PatternDef' is null
) {
9
←
Taking false branch→
  Pattern = PatternDef->getBody(PatternDef);
  PatternDecl = PatternDef;
  if (PatternDef->willHaveBody())
    PatternDef = nullptr;
}

// FIXME: We need to track the instantiation stack in order to know which
// definitions should be visible within this instantiation.
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Function,
10
←
Assuming the condition is false→
11
←
Taking false branch→
                              Function->getInstantiatedFromMemberFunction(),
                                   PatternDecl, PatternDef, TSK,
                                   /*Complain*/DefinitionRequired)) {
  if (DefinitionRequired)
    Function->setInvalidDecl();
  else if (TSK == TSK_ExplicitInstantiationDefinition) {
    // Try again at the end of the translation unit (at which point a
    // definition will be required).
    assert(!Recursive)((void)0);
    Function->setInstantiationIsPending(true);
    PendingInstantiations.push_back(
      std::make_pair(Function, PointOfInstantiation));
  } else if (TSK == TSK_ImplicitInstantiation) {
    if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() &&
        !getSourceManager().isInSystemHeader(PatternDecl->getBeginLoc())) {
      Diag(PointOfInstantiation, diag::warn_func_template_missing)
        << Function;
      Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);
      if (getLangOpts().CPlusPlus11)
        Diag(PointOfInstantiation, diag::note_inst_declaration_hint)
          << Function;
    }
  }

  return;
}

// Postpone late parsed template instantiations.
if (PatternDecl->isLateTemplateParsed() &&
12
←
Assuming the condition is false→
    !LateTemplateParser) {
  Function->setInstantiationIsPending(true);
  LateParsedInstantiations.push_back(
      std::make_pair(Function, PointOfInstantiation));
  return;
}

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

// If we're performing recursive template instantiation, create our own
// queue of pending implicit instantiations that we will instantiate later,
// while we're still within our own instantiation context.
// This has to happen before LateTemplateParser below is called, so that
// it marks vtables used in late parsed templates as used.
GlobalEagerInstantiationScope GlobalInstantiations(*this,
                                                   /*Enabled=*/Recursive);
LocalEagerInstantiationScope LocalInstantiations(*this);

// Call the LateTemplateParser callback if there is a need to late parse
// a templated function definition.
if (!Pattern12.1
'Pattern' is null
1
'Pattern' is null
 && PatternDecl->isLateTemplateParsed() &&
    LateTemplateParser) {
  // FIXME: Optimize to allow individual templates to be deserialized.
  if (PatternDecl->isFromASTFile())
    ExternalSource->ReadLateParsedTemplates(LateParsedTemplateMap);

  auto LPTIter = LateParsedTemplateMap.find(PatternDecl);
  assert(LPTIter != LateParsedTemplateMap.end() &&((void)0)
         "missing LateParsedTemplate")((void)0);
  LateTemplateParser(OpaqueParser, *LPTIter->second);
  Pattern = PatternDecl->getBody(PatternDecl);
}

// Note, we should never try to instantiate a deleted function template.
assert((Pattern || PatternDecl->isDefaulted() ||((void)0)
        PatternDecl->hasSkippedBody()) &&((void)0)
       "unexpected kind of function template definition")((void)0);

// C++1y [temp.explicit]p10:
//   Except for inline functions, declarations with types deduced from their
//   initializer or return value, and class template specializations, other
//   explicit instantiation declarations have the effect of suppressing the
//   implicit instantiation of the entity to which they refer.
if (TSK == TSK_ExplicitInstantiationDeclaration &&
13
←
Assuming 'TSK' is not equal to TSK_ExplicitInstantiationDeclaration→
14
←
Taking false branch→
    !PatternDecl->isInlined() &&
    !PatternDecl->getReturnType()->getContainedAutoType())
  return;

if (PatternDecl->isInlined()) {
15
←
Assuming the condition is false→
16
←
Taking false branch→
  // Function, and all later redeclarations of it (from imported modules,
  // for instance), are now implicitly inline.
  for (auto *D = Function->getMostRecentDecl(); /**/;
       D = D->getPreviousDecl()) {
    D->setImplicitlyInline();
    if (D == Function)
      break;
  }
}

InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);
if (Inst.isInvalid() || Inst.isAlreadyInstantiating())
17
←
Assuming the condition is false→
18
←
Assuming the condition is false→
19
←
Taking false branch→
  return;
PrettyDeclStackTraceEntry CrashInfo(Context, Function, SourceLocation(),
                                    "instantiating function definition");

// The instantiation is visible here, even if it was first declared in an
// unimported module.
Function->setVisibleDespiteOwningModule();

// Copy the inner loc start from the pattern.
Function->setInnerLocStart(PatternDecl->getInnerLocStart());

EnterExpressionEvaluationContext EvalContext(
    *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);

// Introduce a new scope where local variable instantiations will be
// recorded, unless we're actually a member function within a local
// class, in which case we need to merge our results with the parent
// scope (of the enclosing function). The exception is instantiating
// a function template specialization, since the template to be
// instantiated already has references to locals properly substituted.
bool MergeWithParentScope = false;
if (CXXRecordDecl *Rec20.1
'Rec' is null
1
'Rec' is null
 = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
20
←
Assuming the object is not a 'CXXRecordDecl'→
21
←
Taking false branch→
  MergeWithParentScope =
      Rec->isLocalClass() && !Function->isFunctionTemplateSpecialization();

LocalInstantiationScope Scope(*this, MergeWithParentScope);
auto RebuildTypeSourceInfoForDefaultSpecialMembers = [&]() {
  // Special members might get their TypeSourceInfo set up w.r.t the
  // PatternDecl context, in which case parameters could still be pointing
  // back to the original class, make sure arguments are bound to the
  // instantiated record instead.
  assert(PatternDecl->isDefaulted() &&((void)0)
         "Special member needs to be defaulted")((void)0);
  auto PatternSM = getDefaultedFunctionKind(PatternDecl).asSpecialMember();
  if (!(PatternSM == Sema::CXXCopyConstructor ||
        PatternSM == Sema::CXXCopyAssignment ||
        PatternSM == Sema::CXXMoveConstructor ||
        PatternSM == Sema::CXXMoveAssignment))
    return;

  auto *NewRec = dyn_cast<CXXRecordDecl>(Function->getDeclContext());
  const auto *PatternRec =
      dyn_cast<CXXRecordDecl>(PatternDecl->getDeclContext());
  if (!NewRec || !PatternRec)
    return;
  if (!PatternRec->isLambda())
    return;

  struct SpecialMemberTypeInfoRebuilder
      : TreeTransform<SpecialMemberTypeInfoRebuilder> {
    using Base = TreeTransform<SpecialMemberTypeInfoRebuilder>;
    const CXXRecordDecl *OldDecl;
    CXXRecordDecl *NewDecl;

    SpecialMemberTypeInfoRebuilder(Sema &SemaRef, const CXXRecordDecl *O,
                                   CXXRecordDecl *N)
        : TreeTransform(SemaRef), OldDecl(O), NewDecl(N) {}

    bool TransformExceptionSpec(SourceLocation Loc,
                                FunctionProtoType::ExceptionSpecInfo &ESI,
                                SmallVectorImpl<QualType> &Exceptions,
                                bool &Changed) {
      return false;
    }

    QualType TransformRecordType(TypeLocBuilder &TLB, RecordTypeLoc TL) {
      const RecordType *T = TL.getTypePtr();
      RecordDecl *Record = cast_or_null<RecordDecl>(
          getDerived().TransformDecl(TL.getNameLoc(), T->getDecl()));
      if (Record != OldDecl)
        return Base::TransformRecordType(TLB, TL);

      QualType Result = getDerived().RebuildRecordType(NewDecl);
      if (Result.isNull())
        return QualType();

      RecordTypeLoc NewTL = TLB.push<RecordTypeLoc>(Result);
      NewTL.setNameLoc(TL.getNameLoc());
      return Result;
    }
  } IR{*this, PatternRec, NewRec};

  TypeSourceInfo *NewSI = IR.TransformType(Function->getTypeSourceInfo());
  Function->setType(NewSI->getType());
  Function->setTypeSourceInfo(NewSI);

  ParmVarDecl *Parm = Function->getParamDecl(0);
  TypeSourceInfo *NewParmSI = IR.TransformType(Parm->getTypeSourceInfo());
  Parm->setType(NewParmSI->getType());
  Parm->setTypeSourceInfo(NewParmSI);
};

if (PatternDecl->isDefaulted()) {
22
←
Assuming the condition is false→
23
←
Taking false branch→
  RebuildTypeSourceInfoForDefaultSpecialMembers();
  SetDeclDefaulted(Function, PatternDecl->getLocation());
} else {
  MultiLevelTemplateArgumentList TemplateArgs =
    getTemplateInstantiationArgs(Function, nullptr, false, PatternDecl);

  // Substitute into the qualifier; we can get a substitution failure here
  // through evil use of alias templates.
  // FIXME: Is CurContext correct for this? Should we go to the (instantiation
  // of the) lexical context of the pattern?
  SubstQualifier(*this, PatternDecl, Function, TemplateArgs);

  ActOnStartOfFunctionDef(nullptr, Function);

  // Enter the scope of this instantiation. We don't use
  // PushDeclContext because we don't have a scope.
  Sema::ContextRAII savedContext(*this, Function);

  if (addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
24
←
Assuming the condition is false→
25
←
Taking false branch→
                                       TemplateArgs))
    return;

  StmtResult Body;
  if (PatternDecl->hasSkippedBody()) {
26
←
Assuming the condition is false→
27
←
Taking false branch→
    ActOnSkippedFunctionBody(Function);
    Body = nullptr;
  } else {
    if (CXXConstructorDecl *Ctor28.1
'Ctor' is null
1
'Ctor' is null
 = dyn_cast<CXXConstructorDecl>(Function)) {
28
←
Assuming 'Function' is not a 'CXXConstructorDecl'→
29
←
Taking false branch→
      // If this is a constructor, instantiate the member initializers.
      InstantiateMemInitializers(Ctor, cast<CXXConstructorDecl>(PatternDecl),
                                 TemplateArgs);

      // If this is an MS ABI dllexport default constructor, instantiate any
      // default arguments.
      if (Context.getTargetInfo().getCXXABI().isMicrosoft() &&
          Ctor->isDefaultConstructor()) {
        InstantiateDefaultCtorDefaultArgs(Ctor);
      }
    }

    // Instantiate the function body.
    Body = SubstStmt(Pattern, TemplateArgs);

    if (Body.isInvalid())
30
←
Assuming the condition is false→
31
←
Taking false branch→
      Function->setInvalidDecl();
  }
  // FIXME: finishing the function body while in an expression evaluation
  // context seems wrong. Investigate more.
  ActOnFinishFunctionBody(Function, Body.get(), /*IsInstantiation=*/true);

  PerformDependentDiagnostics(PatternDecl, TemplateArgs);

  if (auto *Listener = getASTMutationListener())
32
←
Assuming 'Listener' is null→
33
←
Taking false branch→
    Listener->FunctionDefinitionInstantiated(Function);

  savedContext.pop();
}

DeclGroupRef DG(Function);
Consumer.HandleTopLevelDecl(DG);

// This class may have local implicit instantiations that need to be
// instantiation within this scope.
LocalInstantiations.perform();
Scope.Exit();
GlobalInstantiations.perform();
34
←
Calling 'GlobalEagerInstantiationScope::perform'→
5080}

5082VarTemplateSpecializationDecl *Sema::BuildVarTemplateInstantiation(
  VarTemplateDecl *VarTemplate, VarDecl *FromVar,
  const TemplateArgumentList &TemplateArgList,
  const TemplateArgumentListInfo &TemplateArgsInfo,
  SmallVectorImpl<TemplateArgument> &Converted,
  SourceLocation PointOfInstantiation,
  LateInstantiatedAttrVec *LateAttrs,
  LocalInstantiationScope *StartingScope) {
if (FromVar->isInvalidDecl())
  return nullptr;

InstantiatingTemplate Inst(*this, PointOfInstantiation, FromVar);
if (Inst.isInvalid())
  return nullptr;

MultiLevelTemplateArgumentList TemplateArgLists;
TemplateArgLists.addOuterTemplateArguments(&TemplateArgList);

// Instantiate the first declaration of the variable template: for a partial
// specialization of a static data member template, the first declaration may
// or may not be the declaration in the class; if it's in the class, we want
// to instantiate a member in the class (a declaration), and if it's outside,
// we want to instantiate a definition.
//
// If we're instantiating an explicitly-specialized member template or member
// partial specialization, don't do this. The member specialization completely
// replaces the original declaration in this case.
bool IsMemberSpec = false;
if (VarTemplatePartialSpecializationDecl *PartialSpec =
        dyn_cast<VarTemplatePartialSpecializationDecl>(FromVar))
  IsMemberSpec = PartialSpec->isMemberSpecialization();
else if (VarTemplateDecl *FromTemplate = FromVar->getDescribedVarTemplate())
  IsMemberSpec = FromTemplate->isMemberSpecialization();
if (!IsMemberSpec)
  FromVar = FromVar->getFirstDecl();

MultiLevelTemplateArgumentList MultiLevelList(TemplateArgList);
TemplateDeclInstantiator Instantiator(*this, FromVar->getDeclContext(),
                                      MultiLevelList);

// TODO: Set LateAttrs and StartingScope ...

return cast_or_null<VarTemplateSpecializationDecl>(
    Instantiator.VisitVarTemplateSpecializationDecl(
        VarTemplate, FromVar, TemplateArgsInfo, Converted));
5127}

5129/// Instantiates a variable template specialization by completing it
5130/// with appropriate type information and initializer.
5131VarTemplateSpecializationDecl *Sema::CompleteVarTemplateSpecializationDecl(
  VarTemplateSpecializationDecl *VarSpec, VarDecl *PatternDecl,
  const MultiLevelTemplateArgumentList &TemplateArgs) {
assert(PatternDecl->isThisDeclarationADefinition() &&((void)0)
       "don't have a definition to instantiate from")((void)0);

// Do substitution on the type of the declaration
TypeSourceInfo *DI =
    SubstType(PatternDecl->getTypeSourceInfo(), TemplateArgs,
              PatternDecl->getTypeSpecStartLoc(), PatternDecl->getDeclName());
if (!DI)
  return nullptr;

// Update the type of this variable template specialization.
VarSpec->setType(DI->getType());

// Convert the declaration into a definition now.
VarSpec->setCompleteDefinition();

// Instantiate the initializer.
InstantiateVariableInitializer(VarSpec, PatternDecl, TemplateArgs);

if (getLangOpts().OpenCL)
  deduceOpenCLAddressSpace(VarSpec);

return VarSpec;
5157}

5159/// BuildVariableInstantiation - Used after a new variable has been created.
5160/// Sets basic variable data and decides whether to postpone the
5161/// variable instantiation.
5162void Sema::BuildVariableInstantiation(
  VarDecl *NewVar, VarDecl *OldVar,
  const MultiLevelTemplateArgumentList &TemplateArgs,
  LateInstantiatedAttrVec *LateAttrs, DeclContext *Owner,
  LocalInstantiationScope *StartingScope,
  bool InstantiatingVarTemplate,
  VarTemplateSpecializationDecl *PrevDeclForVarTemplateSpecialization) {
// Instantiating a partial specialization to produce a partial
// specialization.
bool InstantiatingVarTemplatePartialSpec =
    isa<VarTemplatePartialSpecializationDecl>(OldVar) &&
    isa<VarTemplatePartialSpecializationDecl>(NewVar);
// Instantiating from a variable template (or partial specialization) to
// produce a variable template specialization.
bool InstantiatingSpecFromTemplate =
    isa<VarTemplateSpecializationDecl>(NewVar) &&
    (OldVar->getDescribedVarTemplate() ||
     isa<VarTemplatePartialSpecializationDecl>(OldVar));

// If we are instantiating a local extern declaration, the
// instantiation belongs lexically to the containing function.
// If we are instantiating a static data member defined
// out-of-line, the instantiation will have the same lexical
// context (which will be a namespace scope) as the template.
if (OldVar->isLocalExternDecl()) {
  NewVar->setLocalExternDecl();
  NewVar->setLexicalDeclContext(Owner);
} else if (OldVar->isOutOfLine())
  NewVar->setLexicalDeclContext(OldVar->getLexicalDeclContext());
NewVar->setTSCSpec(OldVar->getTSCSpec());
NewVar->setInitStyle(OldVar->getInitStyle());
NewVar->setCXXForRangeDecl(OldVar->isCXXForRangeDecl());
NewVar->setObjCForDecl(OldVar->isObjCForDecl());
NewVar->setConstexpr(OldVar->isConstexpr());
NewVar->setInitCapture(OldVar->isInitCapture());
NewVar->setPreviousDeclInSameBlockScope(
    OldVar->isPreviousDeclInSameBlockScope());
NewVar->setAccess(OldVar->getAccess());

if (!OldVar->isStaticDataMember()) {
  if (OldVar->isUsed(false))
    NewVar->setIsUsed();
  NewVar->setReferenced(OldVar->isReferenced());
}

InstantiateAttrs(TemplateArgs, OldVar, NewVar, LateAttrs, StartingScope);

LookupResult Previous(
    *this, NewVar->getDeclName(), NewVar->getLocation(),
    NewVar->isLocalExternDecl() ? Sema::LookupRedeclarationWithLinkage
                                : Sema::LookupOrdinaryName,
    NewVar->isLocalExternDecl() ? Sema::ForExternalRedeclaration
                                : forRedeclarationInCurContext());

if (NewVar->isLocalExternDecl() && OldVar->getPreviousDecl() &&
    (!OldVar->getPreviousDecl()->getDeclContext()->isDependentContext() ||
     OldVar->getPreviousDecl()->getDeclContext()==OldVar->getDeclContext())) {
  // We have a previous declaration. Use that one, so we merge with the
  // right type.
  if (NamedDecl *NewPrev = FindInstantiatedDecl(
          NewVar->getLocation(), OldVar->getPreviousDecl(), TemplateArgs))
    Previous.addDecl(NewPrev);
} else if (!isa<VarTemplateSpecializationDecl>(NewVar) &&
           OldVar->hasLinkage()) {
  LookupQualifiedName(Previous, NewVar->getDeclContext(), false);
} else if (PrevDeclForVarTemplateSpecialization) {
  Previous.addDecl(PrevDeclForVarTemplateSpecialization);
}
CheckVariableDeclaration(NewVar, Previous);

if (!InstantiatingVarTemplate) {
  NewVar->getLexicalDeclContext()->addHiddenDecl(NewVar);
  if (!NewVar->isLocalExternDecl() || !NewVar->getPreviousDecl())
    NewVar->getDeclContext()->makeDeclVisibleInContext(NewVar);
}

if (!OldVar->isOutOfLine()) {
  if (NewVar->getDeclContext()->isFunctionOrMethod())
    CurrentInstantiationScope->InstantiatedLocal(OldVar, NewVar);
}

// Link instantiations of static data members back to the template from
// which they were instantiated.
//
// Don't do this when instantiating a template (we link the template itself
// back in that case) nor when instantiating a static data member template
// (that's not a member specialization).
if (NewVar->isStaticDataMember() && !InstantiatingVarTemplate &&
    !InstantiatingSpecFromTemplate)
  NewVar->setInstantiationOfStaticDataMember(OldVar,
                                             TSK_ImplicitInstantiation);

// If the pattern is an (in-class) explicit specialization, then the result
// is also an explicit specialization.
if (VarTemplateSpecializationDecl *OldVTSD =
        dyn_cast<VarTemplateSpecializationDecl>(OldVar)) {
  if (OldVTSD->getSpecializationKind() == TSK_ExplicitSpecialization &&
      !isa<VarTemplatePartialSpecializationDecl>(OldVTSD))
    cast<VarTemplateSpecializationDecl>(NewVar)->setSpecializationKind(
        TSK_ExplicitSpecialization);
}

// Forward the mangling number from the template to the instantiated decl.
Context.setManglingNumber(NewVar, Context.getManglingNumber(OldVar));
Context.setStaticLocalNumber(NewVar, Context.getStaticLocalNumber(OldVar));

// Figure out whether to eagerly instantiate the initializer.
if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {
  // We're producing a template. Don't instantiate the initializer yet.
} else if (NewVar->getType()->isUndeducedType()) {
  // We need the type to complete the declaration of the variable.
  InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);
} else if (InstantiatingSpecFromTemplate ||
           (OldVar->isInline() && OldVar->isThisDeclarationADefinition() &&
            !NewVar->isThisDeclarationADefinition())) {
  // Delay instantiation of the initializer for variable template
  // specializations or inline static data members until a definition of the
  // variable is needed.
} else {
  InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);
}

// Diagnose unused local variables with dependent types, where the diagnostic
// will have been deferred.
if (!NewVar->isInvalidDecl() &&
    NewVar->getDeclContext()->isFunctionOrMethod() &&
    OldVar->getType()->isDependentType())
  DiagnoseUnusedDecl(NewVar);
5290}

5292/// Instantiate the initializer of a variable.
5293void Sema::InstantiateVariableInitializer(
  VarDecl *Var, VarDecl *OldVar,
  const MultiLevelTemplateArgumentList &TemplateArgs) {
if (ASTMutationListener *L = getASTContext().getASTMutationListener())
  L->VariableDefinitionInstantiated(Var);

// We propagate the 'inline' flag with the initializer, because it
// would otherwise imply that the variable is a definition for a
// non-static data member.
if (OldVar->isInlineSpecified())
  Var->setInlineSpecified();
else if (OldVar->isInline())
  Var->setImplicitlyInline();

if (OldVar->getInit()) {
  EnterExpressionEvaluationContext Evaluated(
      *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated, Var);

  // Instantiate the initializer.
  ExprResult Init;

  {
    ContextRAII SwitchContext(*this, Var->getDeclContext());
    Init = SubstInitializer(OldVar->getInit(), TemplateArgs,
                            OldVar->getInitStyle() == VarDecl::CallInit);
  }

  if (!Init.isInvalid()) {
    Expr *InitExpr = Init.get();

    if (Var->hasAttr<DLLImportAttr>() &&
        (!InitExpr ||
         !InitExpr->isConstantInitializer(getASTContext(), false))) {
      // Do not dynamically initialize dllimport variables.
    } else if (InitExpr) {
      bool DirectInit = OldVar->isDirectInit();
      AddInitializerToDecl(Var, InitExpr, DirectInit);
    } else
      ActOnUninitializedDecl(Var);
  } else {
    // FIXME: Not too happy about invalidating the declaration
    // because of a bogus initializer.
    Var->setInvalidDecl();
  }
} else {
  // `inline` variables are a definition and declaration all in one; we won't
  // pick up an initializer from anywhere else.
  if (Var->isStaticDataMember() && !Var->isInline()) {
    if (!Var->isOutOfLine())
      return;

    // If the declaration inside the class had an initializer, don't add
    // another one to the out-of-line definition.
    if (OldVar->getFirstDecl()->hasInit())
      return;
  }

  // We'll add an initializer to a for-range declaration later.
  if (Var->isCXXForRangeDecl() || Var->isObjCForDecl())
    return;

  ActOnUninitializedDecl(Var);
}

if (getLangOpts().CUDA)
  checkAllowedCUDAInitializer(Var);
5359}

5361/// Instantiate the definition of the given variable from its
5362/// template.
5363///
5364/// \param PointOfInstantiation the point at which the instantiation was
5365/// required. Note that this is not precisely a "point of instantiation"
5366/// for the variable, but it's close.
5367///
5368/// \param Var the already-instantiated declaration of a templated variable.
5369///
5370/// \param Recursive if true, recursively instantiates any functions that
5371/// are required by this instantiation.
5372///
5373/// \param DefinitionRequired if true, then we are performing an explicit
5374/// instantiation where a definition of the variable is required. Complain
5375/// if there is no such definition.
5376void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
                                       VarDecl *Var, bool Recursive,
                                    bool DefinitionRequired, bool AtEndOfTU) {
if (Var->isInvalidDecl())
52
←
Assuming the condition is false→
53
←
Taking false branch→
  return;

// Never instantiate an explicitly-specialized entity.
TemplateSpecializationKind TSK =
    Var->getTemplateSpecializationKindForInstantiation();
if (TSK == TSK_ExplicitSpecialization)
54
←
Assuming 'TSK' is not equal to TSK_ExplicitSpecialization→
55
←
Taking false branch→
  return;

// Find the pattern and the arguments to substitute into it.
VarDecl *PatternDecl = Var->getTemplateInstantiationPattern();
assert(PatternDecl && "no pattern for templated variable")((void)0);
MultiLevelTemplateArgumentList TemplateArgs =
    getTemplateInstantiationArgs(Var);

VarTemplateSpecializationDecl *VarSpec =
    dyn_cast<VarTemplateSpecializationDecl>(Var);
56
←
Assuming 'Var' is not a 'VarTemplateSpecializationDecl'→
if (VarSpec56.1
'VarSpec' is null
1
'VarSpec' is null
) {
57
←
Taking false branch→
  // If this is a static data member template, there might be an
  // uninstantiated initializer on the declaration. If so, instantiate
  // it now.
  //
  // FIXME: This largely duplicates what we would do below. The difference
  // is that along this path we may instantiate an initializer from an
  // in-class declaration of the template and instantiate the definition
  // from a separate out-of-class definition.
  if (PatternDecl->isStaticDataMember() &&
      (PatternDecl = PatternDecl->getFirstDecl())->hasInit() &&
      !Var->hasInit()) {
    // FIXME: Factor out the duplicated instantiation context setup/tear down
    // code here.
    InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
    if (Inst.isInvalid() || Inst.isAlreadyInstantiating())
      return;
    PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),
                                        "instantiating variable initializer");

    // The instantiation is visible here, even if it was first declared in an
    // unimported module.
    Var->setVisibleDespiteOwningModule();

    // If we're performing recursive template instantiation, create our own
    // queue of pending implicit instantiations that we will instantiate
    // later, while we're still within our own instantiation context.
    GlobalEagerInstantiationScope GlobalInstantiations(*this,
                                                       /*Enabled=*/Recursive);
    LocalInstantiationScope Local(*this);
    LocalEagerInstantiationScope LocalInstantiations(*this);

    // Enter the scope of this instantiation. We don't use
    // PushDeclContext because we don't have a scope.
    ContextRAII PreviousContext(*this, Var->getDeclContext());
    InstantiateVariableInitializer(Var, PatternDecl, TemplateArgs);
    PreviousContext.pop();

    // This variable may have local implicit instantiations that need to be
    // instantiated within this scope.
    LocalInstantiations.perform();
    Local.Exit();
    GlobalInstantiations.perform();
  }
} else {
  assert(Var->isStaticDataMember() && PatternDecl->isStaticDataMember() &&((void)0)
         "not a static data member?")((void)0);
}

VarDecl *Def = PatternDecl->getDefinition(getASTContext());
58
←
'Def' initialized here→

// If we don't have a definition of the variable template, we won't perform
// any instantiation. Rather, we rely on the user to instantiate this
// definition (or provide a specialization for it) in another translation
// unit.
if (!Def && !DefinitionRequired60.1
'DefinitionRequired' is false
1
'DefinitionRequired' is false
) {
59
←
Assuming 'Def' is null→
60
←
Assuming pointer value is null→
61
←
Taking true branch→
  if (TSK == TSK_ExplicitInstantiationDefinition) {
62
←
Assuming 'TSK' is not equal to TSK_ExplicitInstantiationDefinition→
63
←
Taking false branch→
    PendingInstantiations.push_back(
      std::make_pair(Var, PointOfInstantiation));
  } else if (TSK == TSK_ImplicitInstantiation) {
64
←
Assuming 'TSK' is not equal to TSK_ImplicitInstantiation→
65
←
Taking false branch→
    // Warn about missing definition at the end of translation unit.
    if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() &&
        !getSourceManager().isInSystemHeader(PatternDecl->getBeginLoc())) {
      Diag(PointOfInstantiation, diag::warn_var_template_missing)
        << Var;
      Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);
      if (getLangOpts().CPlusPlus11)
        Diag(PointOfInstantiation, diag::note_inst_declaration_hint) << Var;
    }
    return;
  }
}

// FIXME: We need to track the instantiation stack in order to know which
// definitions should be visible within this instantiation.
// FIXME: Produce diagnostics when Var->getInstantiatedFromStaticDataMember().
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Var,
66
←
Assuming the condition is false→
67
←
Taking false branch→
                                   /*InstantiatedFromMember*/false,
                                   PatternDecl, Def, TSK,
                                   /*Complain*/DefinitionRequired))
  return;

// C++11 [temp.explicit]p10:
//   Except for inline functions, const variables of literal types, variables
//   of reference types, [...] explicit instantiation declarations
//   have the effect of suppressing the implicit instantiation of the entity
//   to which they refer.
//
// FIXME: That's not exactly the same as "might be usable in constant
// expressions", which only allows constexpr variables and const integral
// types, not arbitrary const literal types.
if (TSK == TSK_ExplicitInstantiationDeclaration &&
68
←
Assuming 'TSK' is not equal to TSK_ExplicitInstantiationDeclaration→
    !Var->mightBeUsableInConstantExpressions(getASTContext()))
  return;

// Make sure to pass the instantiated variable to the consumer at the end.
struct PassToConsumerRAII {
  ASTConsumer &Consumer;
  VarDecl *Var;

  PassToConsumerRAII(ASTConsumer &Consumer, VarDecl *Var)
    : Consumer(Consumer), Var(Var) { }

  ~PassToConsumerRAII() {
    Consumer.HandleCXXStaticMemberVarInstantiation(Var);
  }
} PassToConsumerRAII(Consumer, Var);

// If we already have a definition, we're done.
if (VarDecl *Def = Var->getDefinition()) {
69
←
Assuming 'Def' is null→
70
←
Taking false branch→
  // We may be explicitly instantiating something we've already implicitly
  // instantiated.
  Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),
                                     PointOfInstantiation);
  return;
}

InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
if (Inst.isInvalid() || Inst.isAlreadyInstantiating())
71
←
Assuming the condition is false→
72
←
Assuming the condition is false→
73
←
Taking false branch→
  return;
PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),
                                    "instantiating variable definition");

// If we're performing recursive template instantiation, create our own
// queue of pending implicit instantiations that we will instantiate later,
// while we're still within our own instantiation context.
GlobalEagerInstantiationScope GlobalInstantiations(*this,
                                                   /*Enabled=*/Recursive);

// Enter the scope of this instantiation. We don't use
// PushDeclContext because we don't have a scope.
ContextRAII PreviousContext(*this, Var->getDeclContext());
LocalInstantiationScope Local(*this);

LocalEagerInstantiationScope LocalInstantiations(*this);

VarDecl *OldVar = Var;
if (Def->isStaticDataMember() && !Def->isOutOfLine()) {
74
←
Called C++ object pointer is null
  // We're instantiating an inline static data member whose definition was
  // provided inside the class.
  InstantiateVariableInitializer(Var, Def, TemplateArgs);
} else if (!VarSpec) {
  Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
                                        TemplateArgs));
} else if (Var->isStaticDataMember() &&
           Var->getLexicalDeclContext()->isRecord()) {
  // We need to instantiate the definition of a static data member template,
  // and all we have is the in-class declaration of it. Instantiate a separate
  // declaration of the definition.
  TemplateDeclInstantiator Instantiator(*this, Var->getDeclContext(),
                                        TemplateArgs);
  Var = cast_or_null<VarDecl>(Instantiator.VisitVarTemplateSpecializationDecl(
      VarSpec->getSpecializedTemplate(), Def, VarSpec->getTemplateArgsInfo(),
      VarSpec->getTemplateArgs().asArray(), VarSpec));
  if (Var) {
    llvm::PointerUnion<VarTemplateDecl *,
                       VarTemplatePartialSpecializationDecl *> PatternPtr =
        VarSpec->getSpecializedTemplateOrPartial();
    if (VarTemplatePartialSpecializationDecl *Partial =
        PatternPtr.dyn_cast<VarTemplatePartialSpecializationDecl *>())
      cast<VarTemplateSpecializationDecl>(Var)->setInstantiationOf(
          Partial, &VarSpec->getTemplateInstantiationArgs());

    // Attach the initializer.
    InstantiateVariableInitializer(Var, Def, TemplateArgs);
  }
} else
  // Complete the existing variable's definition with an appropriately
  // substituted type and initializer.
  Var = CompleteVarTemplateSpecializationDecl(VarSpec, Def, TemplateArgs);

PreviousContext.pop();

if (Var) {
  PassToConsumerRAII.Var = Var;
  Var->setTemplateSpecializationKind(OldVar->getTemplateSpecializationKind(),
                                     OldVar->getPointOfInstantiation());
}

// This variable may have local implicit instantiations that need to be
// instantiated within this scope.
LocalInstantiations.perform();
Local.Exit();
GlobalInstantiations.perform();
5580}

5582void
5583Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
                               const CXXConstructorDecl *Tmpl,
                         const MultiLevelTemplateArgumentList &TemplateArgs) {

SmallVector<CXXCtorInitializer*, 4> NewInits;
bool AnyErrors = Tmpl->isInvalidDecl();

// Instantiate all the initializers.
for (const auto *Init : Tmpl->inits()) {
  // Only instantiate written initializers, let Sema re-construct implicit
  // ones.
  if (!Init->isWritten())
    continue;

  SourceLocation EllipsisLoc;

  if (Init->isPackExpansion()) {
    // This is a pack expansion. We should expand it now.
    TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();
    SmallVector<UnexpandedParameterPack, 4> Unexpanded;
    collectUnexpandedParameterPacks(BaseTL, Unexpanded);
    collectUnexpandedParameterPacks(Init->getInit(), Unexpanded);
    bool ShouldExpand = false;
    bool RetainExpansion = false;
    Optional<unsigned> NumExpansions;
    if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(),
                                        BaseTL.getSourceRange(),
                                        Unexpanded,
                                        TemplateArgs, ShouldExpand,
                                        RetainExpansion,
                                        NumExpansions)) {
      AnyErrors = true;
      New->setInvalidDecl();
      continue;
    }
    assert(ShouldExpand && "Partial instantiation of base initializer?")((void)0);

    // Loop over all of the arguments in the argument pack(s),
    for (unsigned I = 0; I != *NumExpansions; ++I) {
      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);

      // Instantiate the initializer.
      ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
                                             /*CXXDirectInit=*/true);
      if (TempInit.isInvalid()) {
        AnyErrors = true;
        break;
      }

      // Instantiate the base type.
      TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),
                                            TemplateArgs,
                                            Init->getSourceLocation(),
                                            New->getDeclName());
      if (!BaseTInfo) {
        AnyErrors = true;
        break;
      }

      // Build the initializer.
      MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),
                                                   BaseTInfo, TempInit.get(),
                                                   New->getParent(),
                                                   SourceLocation());
      if (NewInit.isInvalid()) {
        AnyErrors = true;
        break;
      }

      NewInits.push_back(NewInit.get());
    }

    continue;
  }

  // Instantiate the initializer.
  ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,
                                         /*CXXDirectInit=*/true);
  if (TempInit.isInvalid()) {
    AnyErrors = true;
    continue;
  }

  MemInitResult NewInit;
  if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {
    TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),
                                      TemplateArgs,
                                      Init->getSourceLocation(),
                                      New->getDeclName());
    if (!TInfo) {
      AnyErrors = true;
      New->setInvalidDecl();
      continue;
    }

    if (Init->isBaseInitializer())
      NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.get(),
                                     New->getParent(), EllipsisLoc);
    else
      NewInit = BuildDelegatingInitializer(TInfo, TempInit.get(),
                                cast<CXXRecordDecl>(CurContext->getParent()));
  } else if (Init->isMemberInitializer()) {
    FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(
                                                   Init->getMemberLocation(),
                                                   Init->getMember(),
                                                   TemplateArgs));
    if (!Member) {
      AnyErrors = true;
      New->setInvalidDecl();
      continue;
    }

    NewInit = BuildMemberInitializer(Member, TempInit.get(),
                                     Init->getSourceLocation());
  } else if (Init->isIndirectMemberInitializer()) {
    IndirectFieldDecl *IndirectMember =
       cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(
                               Init->getMemberLocation(),
                               Init->getIndirectMember(), TemplateArgs));

    if (!IndirectMember) {
      AnyErrors = true;
      New->setInvalidDecl();
      continue;
    }

    NewInit = BuildMemberInitializer(IndirectMember, TempInit.get(),
                                     Init->getSourceLocation());
  }

  if (NewInit.isInvalid()) {
    AnyErrors = true;
    New->setInvalidDecl();
  } else {
    NewInits.push_back(NewInit.get());
  }
}

// Assign all the initializers to the new constructor.
ActOnMemInitializers(New,
                     /*FIXME: ColonLoc */
                     SourceLocation(),
                     NewInits,
                     AnyErrors);
5727}

5729// TODO: this could be templated if the various decl types used the
5730// same method name.
5731static bool isInstantiationOf(ClassTemplateDecl *Pattern,
                            ClassTemplateDecl *Instance) {
Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromMemberTemplate();
} while (Instance);

return false;
5742}

5744static bool isInstantiationOf(FunctionTemplateDecl *Pattern,
                            FunctionTemplateDecl *Instance) {
Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromMemberTemplate();
} while (Instance);

return false;
5755}

5757static bool
5758isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,
                ClassTemplatePartialSpecializationDecl *Instance) {
Pattern
  = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());
do {
  Instance = cast<ClassTemplatePartialSpecializationDecl>(
                                              Instance->getCanonicalDecl());
  if (Pattern == Instance)
    return true;
  Instance = Instance->getInstantiatedFromMember();
} while (Instance);

return false;
5771}

5773static bool isInstantiationOf(CXXRecordDecl *Pattern,
                            CXXRecordDecl *Instance) {
Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromMemberClass();
} while (Instance);

return false;
5784}

5786static bool isInstantiationOf(FunctionDecl *Pattern,
                            FunctionDecl *Instance) {
Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromMemberFunction();
} while (Instance);

return false;
5797}

5799static bool isInstantiationOf(EnumDecl *Pattern,
                            EnumDecl *Instance) {
Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromMemberEnum();
} while (Instance);

return false;
5810}

5812static bool isInstantiationOf(UsingShadowDecl *Pattern,
                            UsingShadowDecl *Instance,
                            ASTContext &C) {
return declaresSameEntity(C.getInstantiatedFromUsingShadowDecl(Instance),
                          Pattern);
5817}

5819static bool isInstantiationOf(UsingDecl *Pattern, UsingDecl *Instance,
                            ASTContext &C) {
return declaresSameEntity(C.getInstantiatedFromUsingDecl(Instance), Pattern);
5822}

5824template<typename T>
5825static bool isInstantiationOfUnresolvedUsingDecl(T *Pattern, Decl *Other,
                                               ASTContext &Ctx) {
// An unresolved using declaration can instantiate to an unresolved using
// declaration, or to a using declaration or a using declaration pack.
//
// Multiple declarations can claim to be instantiated from an unresolved
// using declaration if it's a pack expansion. We want the UsingPackDecl
// in that case, not the individual UsingDecls within the pack.
bool OtherIsPackExpansion;
NamedDecl *OtherFrom;
if (auto *OtherUUD = dyn_cast<T>(Other)) {
  OtherIsPackExpansion = OtherUUD->isPackExpansion();
  OtherFrom = Ctx.getInstantiatedFromUsingDecl(OtherUUD);
} else if (auto *OtherUPD = dyn_cast<UsingPackDecl>(Other)) {
  OtherIsPackExpansion = true;
  OtherFrom = OtherUPD->getInstantiatedFromUsingDecl();
} else if (auto *OtherUD = dyn_cast<UsingDecl>(Other)) {
  OtherIsPackExpansion = false;
  OtherFrom = Ctx.getInstantiatedFromUsingDecl(OtherUD);
} else {
  return false;
}
return Pattern->isPackExpansion() == OtherIsPackExpansion &&
       declaresSameEntity(OtherFrom, Pattern);
5849}

5851static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,
                                            VarDecl *Instance) {
assert(Instance->isStaticDataMember())((void)0);

Pattern = Pattern->getCanonicalDecl();

do {
  Instance = Instance->getCanonicalDecl();
  if (Pattern == Instance) return true;
  Instance = Instance->getInstantiatedFromStaticDataMember();
} while (Instance);

return false;
5864}

5866// Other is the prospective instantiation
5867// D is the prospective pattern
5868static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
if (auto *UUD = dyn_cast<UnresolvedUsingTypenameDecl>(D))
  return isInstantiationOfUnresolvedUsingDecl(UUD, Other, Ctx);

if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(D))
  return isInstantiationOfUnresolvedUsingDecl(UUD, Other, Ctx);

if (D->getKind() != Other->getKind())
  return false;

if (auto *Record = dyn_cast<CXXRecordDecl>(Other))
  return isInstantiationOf(cast<CXXRecordDecl>(D), Record);

if (auto *Function = dyn_cast<FunctionDecl>(Other))
  return isInstantiationOf(cast<FunctionDecl>(D), Function);

if (auto *Enum = dyn_cast<EnumDecl>(Other))
  return isInstantiationOf(cast<EnumDecl>(D), Enum);

if (auto *Var = dyn_cast<VarDecl>(Other))
  if (Var->isStaticDataMember())
    return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);

if (auto *Temp = dyn_cast<ClassTemplateDecl>(Other))
  return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);

if (auto *Temp = dyn_cast<FunctionTemplateDecl>(Other))
  return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);

if (auto *PartialSpec =
        dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))
  return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),
                           PartialSpec);

if (auto *Field = dyn_cast<FieldDecl>(Other)) {
  if (!Field->getDeclName()) {
    // This is an unnamed field.
    return declaresSameEntity(Ctx.getInstantiatedFromUnnamedFieldDecl(Field),
                              cast<FieldDecl>(D));
  }
}

if (auto *Using = dyn_cast<UsingDecl>(Other))
  return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);

if (auto *Shadow = dyn_cast<UsingShadowDecl>(Other))
  return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);

return D->getDeclName() &&
       D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
5918}

5920template<typename ForwardIterator>
5921static NamedDecl *findInstantiationOf(ASTContext &Ctx,
                                    NamedDecl *D,
                                    ForwardIterator first,
                                    ForwardIterator last) {
for (; first != last; ++first)
  if (isInstantiationOf(Ctx, D, *first))
    return cast<NamedDecl>(*first);

return nullptr;
5930}

5932/// Finds the instantiation of the given declaration context
5933/// within the current instantiation.
5934///
5935/// \returns NULL if there was an error
5936DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,
                        const MultiLevelTemplateArgumentList &TemplateArgs) {
if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {
  Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs, true);
  return cast_or_null<DeclContext>(ID);
} else return DC;
5942}

5944/// Determine whether the given context is dependent on template parameters at
5945/// level \p Level or below.
5946///
5947/// Sometimes we only substitute an inner set of template arguments and leave
5948/// the outer templates alone. In such cases, contexts dependent only on the
5949/// outer levels are not effectively dependent.
5950static bool isDependentContextAtLevel(DeclContext *DC, unsigned Level) {
if (!DC->isDependentContext())
  return false;
if (!Level)
  return true;
return cast<Decl>(DC)->getTemplateDepth() > Level;
5956}

5958/// Find the instantiation of the given declaration within the
5959/// current instantiation.
5960///
5961/// This routine is intended to be used when \p D is a declaration
5962/// referenced from within a template, that needs to mapped into the
5963/// corresponding declaration within an instantiation. For example,
5964/// given:
5965///
5966/// \code
5967/// template<typename T>
5968/// struct X {
5969///   enum Kind {
5970///     KnownValue = sizeof(T)
5971///   };
5972///
5973///   bool getKind() const { return KnownValue; }
5974/// };
5975///
5976/// template struct X<int>;
5977/// \endcode
5978///
5979/// In the instantiation of X<int>::getKind(), we need to map the \p
5980/// EnumConstantDecl for \p KnownValue (which refers to
5981/// X<T>::<Kind>::KnownValue) to its instantiation (X<int>::<Kind>::KnownValue).
5982/// \p FindInstantiatedDecl performs this mapping from within the instantiation
5983/// of X<int>.
5984NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
                        const MultiLevelTemplateArgumentList &TemplateArgs,
                        bool FindingInstantiatedContext) {
DeclContext *ParentDC = D->getDeclContext();
// Determine whether our parent context depends on any of the tempalte
// arguments we're currently substituting.
bool ParentDependsOnArgs = isDependentContextAtLevel(
    ParentDC, TemplateArgs.getNumRetainedOuterLevels());
// FIXME: Parmeters of pointer to functions (y below) that are themselves
// parameters (p below) can have their ParentDC set to the translation-unit
// - thus we can not consistently check if the ParentDC of such a parameter
// is Dependent or/and a FunctionOrMethod.
// For e.g. this code, during Template argument deduction tries to
// find an instantiated decl for (T y) when the ParentDC for y is
// the translation unit.
//   e.g. template <class T> void Foo(auto (*p)(T y) -> decltype(y())) {}
//   float baz(float(*)()) { return 0.0; }
//   Foo(baz);
// The better fix here is perhaps to ensure that a ParmVarDecl, by the time
// it gets here, always has a FunctionOrMethod as its ParentDC??
// For now:
//  - as long as we have a ParmVarDecl whose parent is non-dependent and
//    whose type is not instantiation dependent, do nothing to the decl
//  - otherwise find its instantiated decl.
if (isa<ParmVarDecl>(D) && !ParentDependsOnArgs &&
    !cast<ParmVarDecl>(D)->getType()->isInstantiationDependentType())
  return D;
if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
    isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
    (ParentDependsOnArgs && (ParentDC->isFunctionOrMethod() ||
                             isa<OMPDeclareReductionDecl>(ParentDC) ||
                             isa<OMPDeclareMapperDecl>(ParentDC))) ||
    (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
  // D is a local of some kind. Look into the map of local
  // declarations to their instantiations.
  if (CurrentInstantiationScope) {
    if (auto Found = CurrentInstantiationScope->findInstantiationOf(D)) {
      if (Decl *FD = Found->dyn_cast<Decl *>())
        return cast<NamedDecl>(FD);

      int PackIdx = ArgumentPackSubstitutionIndex;
      assert(PackIdx != -1 &&((void)0)
             "found declaration pack but not pack expanding")((void)0);
      typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
      return cast<NamedDecl>((*Found->get<DeclArgumentPack *>())[PackIdx]);
    }
  }

  // If we're performing a partial substitution during template argument
  // deduction, we may not have values for template parameters yet. They
  // just map to themselves.
  if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) ||
      isa<TemplateTemplateParmDecl>(D))
    return D;

  if (D->isInvalidDecl())
    return nullptr;

  // Normally this function only searches for already instantiated declaration
  // however we have to make an exclusion for local types used before
  // definition as in the code:
  //
  //   template<typename T> void f1() {
  //     void g1(struct x1);
  //     struct x1 {};
  //   }
  //
  // In this case instantiation of the type of 'g1' requires definition of
  // 'x1', which is defined later. Error recovery may produce an enum used
  // before definition. In these cases we need to instantiate relevant
  // declarations here.
  bool NeedInstantiate = false;
  if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D))
    NeedInstantiate = RD->isLocalClass();
  else if (isa<TypedefNameDecl>(D) &&
           isa<CXXDeductionGuideDecl>(D->getDeclContext()))
    NeedInstantiate = true;
  else
    NeedInstantiate = isa<EnumDecl>(D);
  if (NeedInstantiate) {
    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
    CurrentInstantiationScope->InstantiatedLocal(D, Inst);
    return cast<TypeDecl>(Inst);
  }

  // If we didn't find the decl, then we must have a label decl that hasn't
  // been found yet.  Lazily instantiate it and return it now.
  assert(isa<LabelDecl>(D))((void)0);

  Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);
  assert(Inst && "Failed to instantiate label??")((void)0);

  CurrentInstantiationScope->InstantiatedLocal(D, Inst);
  return cast<LabelDecl>(Inst);
}

if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
  if (!Record->isDependentContext())
    return D;

  // Determine whether this record is the "templated" declaration describing
  // a class template or class template partial specialization.
  ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();
  if (ClassTemplate)
    ClassTemplate = ClassTemplate->getCanonicalDecl();
  else if (ClassTemplatePartialSpecializationDecl *PartialSpec
             = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record))
    ClassTemplate = PartialSpec->getSpecializedTemplate()->getCanonicalDecl();

  // Walk the current context to find either the record or an instantiation of
  // it.
  DeclContext *DC = CurContext;
  while (!DC->isFileContext()) {
    // If we're performing substitution while we're inside the template
    // definition, we'll find our own context. We're done.
    if (DC->Equals(Record))
      return Record;

    if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {
      // Check whether we're in the process of instantiating a class template
      // specialization of the template we're mapping.
      if (ClassTemplateSpecializationDecl *InstSpec
                    = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){
        ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();
        if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))
          return InstRecord;
      }

      // Check whether we're in the process of instantiating a member class.
      if (isInstantiationOf(Record, InstRecord))
        return InstRecord;
    }

    // Move to the outer template scope.
    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
      if (FD->getFriendObjectKind() && FD->getDeclContext()->isFileContext()){
        DC = FD->getLexicalDeclContext();
        continue;
      }
      // An implicit deduction guide acts as if it's within the class template
      // specialization described by its name and first N template params.
      auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FD);
      if (Guide && Guide->isImplicit()) {
        TemplateDecl *TD = Guide->getDeducedTemplate();
        // Convert the arguments to an "as-written" list.
        TemplateArgumentListInfo Args(Loc, Loc);
        for (TemplateArgument Arg : TemplateArgs.getInnermost().take_front(
                                      TD->getTemplateParameters()->size())) {
          ArrayRef<TemplateArgument> Unpacked(Arg);
          if (Arg.getKind() == TemplateArgument::Pack)
            Unpacked = Arg.pack_elements();
          for (TemplateArgument UnpackedArg : Unpacked)
            Args.addArgument(
                getTrivialTemplateArgumentLoc(UnpackedArg, QualType(), Loc));
        }
        QualType T = CheckTemplateIdType(TemplateName(TD), Loc, Args);
        if (T.isNull())
          return nullptr;
        auto *SubstRecord = T->getAsCXXRecordDecl();
        assert(SubstRecord && "class template id not a class type?")((void)0);
        // Check that this template-id names the primary template and not a
        // partial or explicit specialization. (In the latter cases, it's
        // meaningless to attempt to find an instantiation of D within the
        // specialization.)
        // FIXME: The standard doesn't say what should happen here.
        if (FindingInstantiatedContext &&
            usesPartialOrExplicitSpecialization(
                Loc, cast<ClassTemplateSpecializationDecl>(SubstRecord))) {
          Diag(Loc, diag::err_specialization_not_primary_template)
            << T << (SubstRecord->getTemplateSpecializationKind() ==
                         TSK_ExplicitSpecialization);
          return nullptr;
        }
        DC = SubstRecord;
        continue;
      }
    }

    DC = DC->getParent();
  }

  // Fall through to deal with other dependent record types (e.g.,
  // anonymous unions in class templates).
}

if (!ParentDependsOnArgs)
  return D;

ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);
if (!ParentDC)
  return nullptr;

if (ParentDC != D->getDeclContext()) {
  // We performed some kind of instantiation in the parent context,
  // so now we need to look into the instantiated parent context to
  // find the instantiation of the declaration D.

  // If our context used to be dependent, we may need to instantiate
  // it before performing lookup into that context.
  bool IsBeingInstantiated = false;
  if (CXXRecordDecl *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {
    if (!Spec->isDependentContext()) {
      QualType T = Context.getTypeDeclType(Spec);
      const RecordType *Tag = T->getAs<RecordType>();
      assert(Tag && "type of non-dependent record is not a RecordType")((void)0);
      if (Tag->isBeingDefined())
        IsBeingInstantiated = true;
      if (!Tag->isBeingDefined() &&
          RequireCompleteType(Loc, T, diag::err_incomplete_type))
        return nullptr;

      ParentDC = Tag->getDecl();
    }
  }

  NamedDecl *Result = nullptr;
  // FIXME: If the name is a dependent name, this lookup won't necessarily
  // find it. Does that ever matter?
  if (auto Name = D->getDeclName()) {
    DeclarationNameInfo NameInfo(Name, D->getLocation());
    DeclarationNameInfo NewNameInfo =
        SubstDeclarationNameInfo(NameInfo, TemplateArgs);
    Name = NewNameInfo.getName();
    if (!Name)
      return nullptr;
    DeclContext::lookup_result Found = ParentDC->lookup(Name);

    Result = findInstantiationOf(Context, D, Found.begin(), Found.end());
  } else {
    // Since we don't have a name for the entity we're looking for,
    // our only option is to walk through all of the declarations to
    // find that name. This will occur in a few cases:
    //
    //   - anonymous struct/union within a template
    //   - unnamed class/struct/union/enum within a template
    //
    // FIXME: Find a better way to find these instantiations!
    Result = findInstantiationOf(Context, D,
                                 ParentDC->decls_begin(),
                                 ParentDC->decls_end());
  }

  if (!Result) {
    if (isa<UsingShadowDecl>(D)) {
      // UsingShadowDecls can instantiate to nothing because of using hiding.
    } else if (hasUncompilableErrorOccurred()) {
      // We've already complained about some ill-formed code, so most likely
      // this declaration failed to instantiate. There's no point in
      // complaining further, since this is normal in invalid code.
      // FIXME: Use more fine-grained 'invalid' tracking for this.
    } else if (IsBeingInstantiated) {
      // The class in which this member exists is currently being
      // instantiated, and we haven't gotten around to instantiating this
      // member yet. This can happen when the code uses forward declarations
      // of member classes, and introduces ordering dependencies via
      // template instantiation.
      Diag(Loc, diag::err_member_not_yet_instantiated)
        << D->getDeclName()
        << Context.getTypeDeclType(cast<CXXRecordDecl>(ParentDC));
      Diag(D->getLocation(), diag::note_non_instantiated_member_here);
    } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
      // This enumeration constant was found when the template was defined,
      // but can't be found in the instantiation. This can happen if an
      // unscoped enumeration member is explicitly specialized.
      EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());
      EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,
                                                           TemplateArgs));
      assert(Spec->getTemplateSpecializationKind() ==((void)0)
               TSK_ExplicitSpecialization)((void)0);
      Diag(Loc, diag::err_enumerator_does_not_exist)
        << D->getDeclName()
        << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));
      Diag(Spec->getLocation(), diag::note_enum_specialized_here)
        << Context.getTypeDeclType(Spec);
    } else {
      // We should have found something, but didn't.
      llvm_unreachable("Unable to find instantiation of declaration!")__builtin_unreachable();
    }
  }

  D = Result;
}

return D;
6268}

6270/// Performs template instantiation for all implicit template
6271/// instantiations we have seen until this point.
6272void Sema::PerformPendingInstantiations(bool LocalOnly) {
std::deque<PendingImplicitInstantiation> delayedPCHInstantiations;
while (!PendingLocalImplicitInstantiations.empty() ||
38
←
Assuming the condition is false→
40
←
Loop condition is true.  Entering loop body→
       (!LocalOnly38.1
'LocalOnly' is false
1
'LocalOnly' is false
 && !PendingInstantiations.empty())) {
39
←
Assuming the condition is true→
  PendingImplicitInstantiation Inst;

  if (PendingLocalImplicitInstantiations.empty()) {
41
←
Assuming the condition is false→
42
←
Taking false branch→
    Inst = PendingInstantiations.front();
    PendingInstantiations.pop_front();
  } else {
    Inst = PendingLocalImplicitInstantiations.front();
    PendingLocalImplicitInstantiations.pop_front();
  }

  // Instantiate function definitions
  if (FunctionDecl *Function43.1
'Function' is null
1
'Function' is null
 = dyn_cast<FunctionDecl>(Inst.first)) {
43
←
Assuming field 'first' is not a 'FunctionDecl'→
44
←
Taking false branch→
    bool DefinitionRequired = Function->getTemplateSpecializationKind() ==
                              TSK_ExplicitInstantiationDefinition;
    if (Function->isMultiVersion()) {
      getASTContext().forEachMultiversionedFunctionVersion(
          Function, [this, Inst, DefinitionRequired](FunctionDecl *CurFD) {
            InstantiateFunctionDefinition(/*FIXME:*/ Inst.second, CurFD, true,
1
Calling 'Sema::InstantiateFunctionDefinition'→
                                          DefinitionRequired, true);
            if (CurFD->isDefined())
              CurFD->setInstantiationIsPending(false);
          });
    } else {
      InstantiateFunctionDefinition(/*FIXME:*/ Inst.second, Function, true,
                                    DefinitionRequired, true);
      if (Function->isDefined())
        Function->setInstantiationIsPending(false);
    }
    // Definition of a PCH-ed template declaration may be available only in the TU.
    if (!LocalOnly && LangOpts.PCHInstantiateTemplates &&
        TUKind == TU_Prefix && Function->instantiationIsPending())
      delayedPCHInstantiations.push_back(Inst);
    continue;
  }

  // Instantiate variable definitions
  VarDecl *Var = cast<VarDecl>(Inst.first);
45
←
Field 'first' is a 'VarDecl'→

  assert((Var->isStaticDataMember() ||((void)0)
          isa<VarTemplateSpecializationDecl>(Var)) &&((void)0)
         "Not a static data member, nor a variable template"((void)0)
         " specialization?")((void)0);

  // Don't try to instantiate declarations if the most recent redeclaration
  // is invalid.
  if (Var->getMostRecentDecl()->isInvalidDecl())
46
←
Assuming the condition is false→
47
←
Taking false branch→
    continue;

  // Check if the most recent declaration has changed the specialization kind
  // and removed the need for implicit instantiation.
  switch (Var->getMostRecentDecl()
48
←
Control jumps to 'case TSK_ImplicitInstantiation:'  at line 6339→
              ->getTemplateSpecializationKindForInstantiation()) {
  case TSK_Undeclared:
    llvm_unreachable("Cannot instantitiate an undeclared specialization.")__builtin_unreachable();
  case TSK_ExplicitInstantiationDeclaration:
  case TSK_ExplicitSpecialization:
    continue;  // No longer need to instantiate this type.
  case TSK_ExplicitInstantiationDefinition:
    // We only need an instantiation if the pending instantiation *is* the
    // explicit instantiation.
    if (Var != Var->getMostRecentDecl())
      continue;
    break;
  case TSK_ImplicitInstantiation:
    break;
49
←
 Execution continues on line 6343→
  }

  PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),
                                      "instantiating variable definition");
  bool DefinitionRequired = Var->getTemplateSpecializationKind() ==
50
←
Assuming the condition is false→
                            TSK_ExplicitInstantiationDefinition;

  // Instantiate static data member definitions or variable template
  // specializations.
  InstantiateVariableDefinition(/*FIXME:*/ Inst.second, Var, true,
51
←
Calling 'Sema::InstantiateVariableDefinition'→
                                DefinitionRequired, true);
}

if (!LocalOnly && LangOpts.PCHInstantiateTemplates)
  PendingInstantiations.swap(delayedPCHInstantiations);
6356}

6358void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs) {
for (auto DD : Pattern->ddiags()) {
  switch (DD->getKind()) {
  case DependentDiagnostic::Access:
    HandleDependentAccessCheck(*DD, TemplateArgs);
    break;
  }
}
6367}

←

/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; }

  /// 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) {
35
←
Assuming field 'Enabled' is true→
36
←
Taking true branch→
      S.DefineUsedVTables();
      S.PerformPendingInstantiations();
37
←
Calling 'Sema::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