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GH70601 #81095

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15 changes: 9 additions & 6 deletions clang/include/clang/Sema/Sema.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8343,12 +8343,14 @@ class Sema final {
ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs,
TemplateTypeParmDecl *ConstrainedParameter,
SourceLocation EllipsisLoc);
SourceLocation EllipsisLoc,
bool EvaluateConstraint = true);

bool AttachTypeConstraint(AutoTypeLoc TL,
NonTypeTemplateParmDecl *NewConstrainedParm,
NonTypeTemplateParmDecl *OrigConstrainedParm,
SourceLocation EllipsisLoc);
SourceLocation EllipsisLoc,
bool EvaluateConstraint = true);

bool RequireStructuralType(QualType T, SourceLocation Loc);

Expand Down Expand Up @@ -8479,11 +8481,11 @@ class Sema final {
const TemplateArgumentListInfo *TemplateArgs);

ExprResult
CheckConceptTemplateId(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
CheckConceptTemplateId(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
const DeclarationNameInfo &ConceptNameInfo,
NamedDecl *FoundDecl, ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs);
const TemplateArgumentListInfo *TemplateArgs,
bool EvaluateConstraint = true);

void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);

Expand Down Expand Up @@ -10518,7 +10520,8 @@ class Sema final {

bool SubstTypeConstraint(TemplateTypeParmDecl *Inst, const TypeConstraint *TC,
const MultiLevelTemplateArgumentList &TemplateArgs,
bool EvaluateConstraint);
bool RebuildConstraint,
bool EvaluateConstraints = true);

bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
ParmVarDecl *Param);
Expand Down
83 changes: 43 additions & 40 deletions clang/lib/Sema/SemaTemplate.cpp
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Expand Up @@ -1176,13 +1176,13 @@ bool Sema::BuildTypeConstraint(const CXXScopeSpec &SS,
ConstrainedParameter, EllipsisLoc);
}

template<typename ArgumentLocAppender>
template <typename ArgumentLocAppender>
static ExprResult formImmediatelyDeclaredConstraint(
Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
SourceLocation RAngleLoc, QualType ConstrainedType,
SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
SourceLocation EllipsisLoc) {
SourceLocation EllipsisLoc, bool EvaluateConstraint) {

TemplateArgumentListInfo ConstraintArgs;
ConstraintArgs.addArgument(
Expand Down Expand Up @@ -1233,7 +1233,8 @@ bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs,
TemplateTypeParmDecl *ConstrainedParameter,
SourceLocation EllipsisLoc) {
SourceLocation EllipsisLoc,
bool EvaluateConstraint) {
// C++2a [temp.param]p4:
// [...] If Q is of the form C<A1, ..., An>, then let E' be
// C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
Expand All @@ -1243,17 +1244,17 @@ bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,

QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);

ExprResult ImmediatelyDeclaredConstraint =
formImmediatelyDeclaredConstraint(
*this, NS, NameInfo, NamedConcept,
TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
ParamAsArgument, ConstrainedParameter->getLocation(),
[&] (TemplateArgumentListInfo &ConstraintArgs) {
if (TemplateArgs)
for (const auto &ArgLoc : TemplateArgs->arguments())
ConstraintArgs.addArgument(ArgLoc);
}, EllipsisLoc);
ExprResult ImmediatelyDeclaredConstraint = formImmediatelyDeclaredConstraint(
*this, NS, NameInfo, NamedConcept,
TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
ParamAsArgument, ConstrainedParameter->getLocation(),
[&](TemplateArgumentListInfo &ConstraintArgs) {
if (TemplateArgs)
for (const auto &ArgLoc : TemplateArgs->arguments())
ConstraintArgs.addArgument(ArgLoc);
},
EllipsisLoc, EvaluateConstraint);
if (ImmediatelyDeclaredConstraint.isInvalid())
return true;

Expand All @@ -1271,7 +1272,8 @@ bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
bool Sema::AttachTypeConstraint(AutoTypeLoc TL,
NonTypeTemplateParmDecl *NewConstrainedParm,
NonTypeTemplateParmDecl *OrigConstrainedParm,
SourceLocation EllipsisLoc) {
SourceLocation EllipsisLoc,
bool EvaluateConstraint) {
if (NewConstrainedParm->getType() != TL.getType() ||
TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
Diag(NewConstrainedParm->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
Expand All @@ -1296,7 +1298,7 @@ bool Sema::AttachTypeConstraint(AutoTypeLoc TL,
for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
ConstraintArgs.addArgument(TL.getArgLoc(I));
},
EllipsisLoc);
EllipsisLoc, EvaluateConstraint);
if (ImmediatelyDeclaredConstraint.isInvalid() ||
!ImmediatelyDeclaredConstraint.isUsable())
return true;
Expand Down Expand Up @@ -4990,13 +4992,11 @@ void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
}
}

ExprResult
Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
const DeclarationNameInfo &ConceptNameInfo,
NamedDecl *FoundDecl,
ConceptDecl *NamedConcept,
const TemplateArgumentListInfo *TemplateArgs) {
ExprResult Sema::CheckConceptTemplateId(
const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
const DeclarationNameInfo &ConceptNameInfo, NamedDecl *FoundDecl,
ConceptDecl *NamedConcept, const TemplateArgumentListInfo *TemplateArgs,
bool EvaluateConstraint) {
assert(NamedConcept && "A concept template id without a template?");

llvm::SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
Expand All @@ -5011,30 +5011,33 @@ Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
Context, NamedConcept->getDeclContext(), NamedConcept->getLocation(),
CanonicalConverted);
ConstraintSatisfaction Satisfaction;
bool AreArgsDependent =
TemplateSpecializationType::anyDependentTemplateArguments(
bool ShouldEvaluate =
EvaluateConstraint &&
!TemplateSpecializationType::anyDependentTemplateArguments(
*TemplateArgs, CanonicalConverted);
MultiLevelTemplateArgumentList MLTAL(NamedConcept, CanonicalConverted,
/*Final=*/false);
LocalInstantiationScope Scope(*this);

EnterExpressionEvaluationContext EECtx{
*this, ExpressionEvaluationContext::ConstantEvaluated, CSD};

if (!AreArgsDependent &&
CheckConstraintSatisfaction(
NamedConcept, {NamedConcept->getConstraintExpr()}, MLTAL,
SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(),
TemplateArgs->getRAngleLoc()),
Satisfaction))
return ExprError();
if (ShouldEvaluate) {
MultiLevelTemplateArgumentList MLTAL(NamedConcept, CanonicalConverted,
/*Final=*/false);
LocalInstantiationScope Scope(*this);

EnterExpressionEvaluationContext EECtx{
*this, ExpressionEvaluationContext::ConstantEvaluated, CSD};

if (CheckConstraintSatisfaction(
NamedConcept, {NamedConcept->getConstraintExpr()}, MLTAL,
SourceRange(SS.isSet() ? SS.getBeginLoc()
: ConceptNameInfo.getLoc(),
TemplateArgs->getRAngleLoc()),
Satisfaction))
return ExprError();
}
auto *CL = ConceptReference::Create(
Context,
SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs));
return ConceptSpecializationExpr::Create(
Context, CL, CSD, AreArgsDependent ? nullptr : &Satisfaction);
Context, CL, CSD, !ShouldEvaluate ? nullptr : &Satisfaction);
}

ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
Expand Down
21 changes: 10 additions & 11 deletions clang/lib/Sema/SemaTemplateInstantiate.cpp
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Expand Up @@ -2878,20 +2878,18 @@ namespace {

bool Sema::SubstTypeConstraint(
TemplateTypeParmDecl *Inst, const TypeConstraint *TC,
const MultiLevelTemplateArgumentList &TemplateArgs,
bool EvaluateConstraints) {
const ASTTemplateArgumentListInfo *TemplArgInfo =
TC->getTemplateArgsAsWritten();

if (!EvaluateConstraints) {
Inst->setTypeConstraint(TC->getConceptReference(),
TC->getImmediatelyDeclaredConstraint());
return false;
const MultiLevelTemplateArgumentList &TemplateArgs, bool RebuildConstraint,
bool EvaluateConstraint) {
if (!RebuildConstraint) {
Inst->setTypeConstraint(TC->getConceptReference(),
TC->getImmediatelyDeclaredConstraint());
return false;
}

TemplateArgumentListInfo InstArgs;

if (TemplArgInfo) {
if (const ASTTemplateArgumentListInfo *TemplArgInfo =
TC->getTemplateArgsAsWritten()) {
InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
if (SubstTemplateArguments(TemplArgInfo->arguments(), TemplateArgs,
Expand All @@ -2904,7 +2902,8 @@ bool Sema::SubstTypeConstraint(
Inst->isParameterPack()
? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
->getEllipsisLoc()
: SourceLocation());
: SourceLocation(),
EvaluateConstraint);
}

ParmVarDecl *Sema::SubstParmVarDecl(
Expand Down
12 changes: 11 additions & 1 deletion clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
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Expand Up @@ -2903,10 +2903,20 @@ Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
Inst->setImplicit(D->isImplicit());
if (auto *TC = D->getTypeConstraint()) {
if (!D->isImplicit()) {
bool RebuildConstraint = [&] {
if (EvaluateConstraints)
return true;
for (auto Active = SemaRef.CodeSynthesisContexts.rbegin();
Active != SemaRef.CodeSynthesisContexts.rend(); ++Active) {
if (llvm::isa_and_present<TypeAliasTemplateDecl>(Active->Entity))
return true;
}
return false;
}();
// Invented template parameter type constraints will be instantiated
// with the corresponding auto-typed parameter as it might reference
// other parameters.
if (SemaRef.SubstTypeConstraint(Inst, TC, TemplateArgs,
if (SemaRef.SubstTypeConstraint(Inst, TC, TemplateArgs, RebuildConstraint,
EvaluateConstraints))
return nullptr;
}
Expand Down
19 changes: 19 additions & 0 deletions clang/test/SemaTemplate/concepts-lambda.cpp
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Expand Up @@ -167,3 +167,22 @@ void foo() {
}(x);
}
} // namespace GH73418

namespace GH70601 {

template <class>
concept C = true;

template <class T, class U>
concept D = C<T> && C<U>;

template <class T>
using Type = decltype([]<C U> {
return []<D<U> V>(V val) {
return val;
}(U());
}.template operator()<T>());

static_assert(__is_same(Type<int>, int));

} // namespace GH70601