https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/219865
Backport 52774473867e49b5891ab9381accf4e5a3ce0024 Requested by: @frederick-vs-ja >From dc5701dd47b9423dcd8f9e47df1f90b77bcdc2f6 Mon Sep 17 00:00:00 2001 From: Chuanqi Xu <[email protected]> Date: Thu, 27 Aug 2026 20:35:27 +0800 Subject: [PATCH] [C++20] [Modules] Handling merging predefined decls from std (#219151) Close https://github.com/llvm/llvm-project/issues/218152 This was only reported in windows as MSSTL chose to implement std module by wrapping the STL into extern "C++", which is different from libstdc++ and libc++. But technically this is not specific to windows and we're able to preoduce it in linux although we won't face it in linux. (cherry picked from commit 52774473867e49b5891ab9381accf4e5a3ce0024) --- clang/lib/Sema/SemaDecl.cpp | 2 +- clang/test/Modules/pr218152.cppm | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) create mode 100644 clang/test/Modules/pr218152.cppm diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index 27fe259af3717..6a25a799aa219 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -18387,7 +18387,7 @@ Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc, } if (getLangOpts().CPlusPlus && Name && DC && StdNamespace && - DC->Equals(getStdNamespace())) { + DC->getRedeclContext()->Equals(getStdNamespace())) { if (Name->isStr("bad_alloc")) { // This is a declaration of or a reference to "std::bad_alloc". isStdBadAlloc = true; diff --git a/clang/test/Modules/pr218152.cppm b/clang/test/Modules/pr218152.cppm new file mode 100644 index 0000000000000..c7b82372f42d6 --- /dev/null +++ b/clang/test/Modules/pr218152.cppm @@ -0,0 +1,17 @@ +// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s + +// expected-no-diagnostics +export module fake_std; + +extern "C++" { +namespace std { + using size_t = decltype(sizeof 0); + export enum class align_val_t : size_t {}; +} // namespace std + +export void *operator new(std::size_t, std::align_val_t); + +namespace std { +void foo() { align_val_t x{}; } +} // namespace std +} // extern "C++" _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
