https://github.com/zyn0217 created https://github.com/llvm/llvm-project/pull/141547
I think the intent of df18ee96206 was to substitute only those non-packs into a pack expansion type (e.g. `T` in `T::pack`...), so let's hold off pack expansions explicitly, in case there are calls coming from a substitution of pack expansion. Fixes https://github.com/llvm/llvm-project/issues/53609 >From e20d9aec39ea1360c7233bca397cada640a8c36f Mon Sep 17 00:00:00 2001 From: Younan Zhang <zyn7...@gmail.com> Date: Tue, 27 May 2025 14:07:00 +0800 Subject: [PATCH] [Clang] Fix a pack expansion bug in template argument deduction I think the intent of df18ee96206 was to substitute only those non-packs into a pack expansion type (e.g. `T` in `T::pack`...), so let's hold off pack expansions explicitly, in case there are calls coming from a substitution of pack expansion. --- clang/docs/ReleaseNotes.rst | 1 + clang/lib/Sema/SemaTemplateDeduction.cpp | 1 + .../CXX/temp/temp.fct.spec/temp.deduct/p7.cpp | 17 +++++++++++++++++ 3 files changed, 19 insertions(+) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index b93fa33acc2a0..2c46a8f8ac86d 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -795,6 +795,7 @@ Bug Fixes to C++ Support - Fix instantiation of default-initialized variable template specialization. (#GH140632) (#GH140622) - Clang modules now allow a module and its user to differ on TrivialAutoVarInit* - Fixed an access checking bug when initializing non-aggregates in default arguments (#GH62444), (#GH83608) +- Fixed a pack substitution bug in deducing class template partial specializations. (#GH53609) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp index 217d57d67f067..75ae04b27d06a 100644 --- a/clang/lib/Sema/SemaTemplateDeduction.cpp +++ b/clang/lib/Sema/SemaTemplateDeduction.cpp @@ -2946,6 +2946,7 @@ ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param, LocalInstantiationScope Scope(S); MultiLevelTemplateArgumentList Args(Template, CTAI.SugaredConverted, /*Final=*/true); + Sema::ArgPackSubstIndexRAII OnlySubstNonPackExpansion(S, std::nullopt); if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) { Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template, diff --git a/clang/test/CXX/temp/temp.fct.spec/temp.deduct/p7.cpp b/clang/test/CXX/temp/temp.fct.spec/temp.deduct/p7.cpp index f0ab7b8ea7612..de6fa0c837e2a 100644 --- a/clang/test/CXX/temp/temp.fct.spec/temp.deduct/p7.cpp +++ b/clang/test/CXX/temp/temp.fct.spec/temp.deduct/p7.cpp @@ -54,3 +54,20 @@ namespace reversed_operator_substitution_order { float &s = no_adl::f<int>(true); } #endif + +namespace GH53609 { + +template <class, int> +struct a; + +template <class, class...> +struct b; + +template <class x, class... y, y... z> +struct b<x, a<y, z>...> {}; + +template <class... x> struct c: b<x>... {}; + +c<int> d; + +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
