llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Younan Zhang (zyn0217) <details> <summary>Changes</summary> TypedefNameDecl referenced by a synthesized CTAD guide for type aliases was not transformed previously, resulting in a substitution failure in `BuildDeductionGuideForTypeAlias()` when substituting into the right-hand-side deduction guide. This patch fixes it in the way we have been doing since https://reviews.llvm.org/D80743. We transform all the function parameters, parenting referenced TypedefNameDecls with the CXXDeductionGuideDecl. Then we instantiate these declarations in FindInstantiatedDecl() as we build up the eventual deduction guide, using the mechanism introduced in D80743 Fixes #<!-- -->111508 --- Full diff: https://github.com/llvm/llvm-project/pull/111804.diff 2 Files Affected: - (modified) clang/lib/Sema/SemaTemplateDeductionGuide.cpp (+18-3) - (modified) clang/test/SemaCXX/cxx20-ctad-type-alias.cpp (+13) ``````````diff diff --git a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp index ca93c840f03215..871c705ab65421 100644 --- a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp +++ b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp @@ -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) { @@ -1215,10 +1215,25 @@ FunctionTemplateDecl *DeclareAggregateDeductionGuideForTypeAlias( getRHSTemplateDeclAndArgs(SemaRef, AliasTemplate).first; if (!RHSTemplate) return nullptr; + + llvm::SmallVector<TypedefNameDecl *, 4> 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); } diff --git a/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp b/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp index 5392573fcdb9d5..675c32a81f1ae8 100644 --- a/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp +++ b/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp @@ -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 `````````` </details> https://github.com/llvm/llvm-project/pull/111804 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
