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[Clang] Instantiate Typedefs referenced by type alias deduction guides #111804

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Merged
merged 2 commits into from
Oct 11, 2024
Merged

[Clang] Instantiate Typedefs referenced by type alias deduction guides #111804

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1319a3c
[Clang] Instantiate Typedefs referenced by type alias deduction guides
zyn0217 Oct 10, 2024
f53aa1b
Let SmallVector pick up the default size
zyn0217 Oct 11, 2024
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21 changes: 18 additions & 3 deletions clang/lib/Sema/SemaTemplateDeductionGuide.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -70,8 +70,8 @@ class ExtractTypeForDeductionGuide
ExtractTypeForDeductionGuide(
Sema &SemaRef,
llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs,
ClassTemplateDecl *NestedPattern,
const MultiLevelTemplateArgumentList *OuterInstantiationArgs)
ClassTemplateDecl *NestedPattern = nullptr,
const MultiLevelTemplateArgumentList *OuterInstantiationArgs = nullptr)
: Base(SemaRef), MaterializedTypedefs(MaterializedTypedefs),
NestedPattern(NestedPattern),
OuterInstantiationArgs(OuterInstantiationArgs) {
Expand Down Expand Up @@ -1215,10 +1215,25 @@ FunctionTemplateDecl *DeclareAggregateDeductionGuideForTypeAlias(
getRHSTemplateDeclAndArgs(SemaRef, AliasTemplate).first;
if (!RHSTemplate)
return nullptr;

llvm::SmallVector<TypedefNameDecl *> TypedefDecls;
llvm::SmallVector<QualType> NewParamTypes;
ExtractTypeForDeductionGuide TypeAliasTransformer(SemaRef, TypedefDecls);
for (QualType P : ParamTypes) {
QualType Type = TypeAliasTransformer.TransformType(P);
if (Type.isNull())
return nullptr;
NewParamTypes.push_back(Type);
}

auto *RHSDeductionGuide = SemaRef.DeclareAggregateDeductionGuideFromInitList(
RHSTemplate, ParamTypes, Loc);
RHSTemplate, NewParamTypes, Loc);
if (!RHSDeductionGuide)
return nullptr;

for (TypedefNameDecl *TD : TypedefDecls)
TD->setDeclContext(RHSDeductionGuide->getTemplatedDecl());

return BuildDeductionGuideForTypeAlias(SemaRef, AliasTemplate,
RHSDeductionGuide, Loc);
}
Expand Down
13 changes: 13 additions & 0 deletions clang/test/SemaCXX/cxx20-ctad-type-alias.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -481,3 +481,16 @@ struct Out {
Out<float>::B out(100); // deduced to Out<float>::A<float>;
static_assert(__is_same(decltype(out), Out<float>::A<float>));
}

namespace GH111508 {

template <typename V> struct S {
using T = V;
T Data;
};

template <typename V> using Alias = S<V>;

Alias A(42);

} // namespace GH111508
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