https://github.com/zyn0217 created https://github.com/llvm/llvm-project/pull/107561
`FunctionParmPackExpr`s are peculiar in that they have to be of unexpanded dependency while they don't introduce any unexpanded packs. So this patch rules them out in the non-empty pack assertion in `DiagnoseUnexpandedParameterPack()` There was a fix #69224, but that turned out to be insufficient. I also moved the separate tests to a pre-existing file. Fixes https://github.com/llvm/llvm-project/issues/86361 >From 92a30ff72fd922df3c29ac31fc2c7d46df1ff84e Mon Sep 17 00:00:00 2001 From: Younan Zhang <zyn7...@gmail.com> Date: Fri, 6 Sep 2024 18:35:45 +0800 Subject: [PATCH] [Clang] Don't assert non-empty packs for FunctionParmPackExprs --- clang/docs/ReleaseNotes.rst | 2 +- clang/lib/Sema/SemaTemplateVariadic.cpp | 33 ++++++++++++++------ clang/test/SemaCXX/lambda-pack-expansion.cpp | 22 +++++++++++++ clang/test/SemaCXX/pr61460.cpp | 13 -------- 4 files changed, 47 insertions(+), 23 deletions(-) delete mode 100644 clang/test/SemaCXX/pr61460.cpp diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index a2e91fd648cce2..3b63b78521e351 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -368,8 +368,8 @@ Bug Fixes to C++ Support - Fixed a bug in the substitution of empty pack indexing types. (#GH105903) - Clang no longer tries to capture non-odr used default arguments of template parameters of generic lambdas (#GH107048) - Fixed a bug where defaulted comparison operators would remove ``const`` from base classes. (#GH102588) - - Fix a crash when using ``source_location`` in the trailing return type of a lambda expression. (#GH67134) +- A follow-up fix was added for (#GH61460), as the previous fix was not entirely correct. (#GH86361) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp index bcd31c98871e22..0a9fd9ab8a5fe1 100644 --- a/clang/lib/Sema/SemaTemplateVariadic.cpp +++ b/clang/lib/Sema/SemaTemplateVariadic.cpp @@ -38,6 +38,7 @@ namespace { bool InLambda = false; unsigned DepthLimit = (unsigned)-1; + bool ContainsFunctionParmPackExpr = false; void addUnexpanded(NamedDecl *ND, SourceLocation Loc = SourceLocation()) { if (auto *VD = dyn_cast<VarDecl>(ND)) { @@ -280,6 +281,15 @@ namespace { return inherited::TraverseLambdaCapture(Lambda, C, Init); } + + bool TraverseFunctionParmPackExpr(FunctionParmPackExpr *) { + ContainsFunctionParmPackExpr = true; + return true; + } + + bool containsFunctionParmPackExpr() const { + return ContainsFunctionParmPackExpr; + } }; } @@ -414,16 +424,21 @@ bool Sema::DiagnoseUnexpandedParameterPack(Expr *E, if (!E->containsUnexpandedParameterPack()) return false; - // CollectUnexpandedParameterPacksVisitor does not expect to see a - // FunctionParmPackExpr, but diagnosing unexpected parameter packs may still - // see such an expression in a lambda body. - // We'll bail out early in this case to avoid triggering an assertion. - if (isa<FunctionParmPackExpr>(E) && getEnclosingLambda()) - return false; - + // FunctionParmPackExprs are special: + // + // 1) they're used to model DeclRefExprs to packs that have been expanded but + // had that expansion held off in the process of transformation. + // + // 2) they always have the unexpanded dependencies but don't introduce new + // unexpanded packs. + // + // We might encounter a FunctionParmPackExpr being a full expression, which a + // larger CXXFoldExpr would expand. SmallVector<UnexpandedParameterPack, 2> Unexpanded; - CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseStmt(E); - assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); + CollectUnexpandedParameterPacksVisitor Visitor(Unexpanded); + Visitor.TraverseStmt(E); + assert((!Unexpanded.empty() || Visitor.containsFunctionParmPackExpr()) && + "Unable to find unexpanded parameter packs"); return DiagnoseUnexpandedParameterPacks(E->getBeginLoc(), UPPC, Unexpanded); } diff --git a/clang/test/SemaCXX/lambda-pack-expansion.cpp b/clang/test/SemaCXX/lambda-pack-expansion.cpp index 77b2e244753a94..5c702e1166a6bc 100644 --- a/clang/test/SemaCXX/lambda-pack-expansion.cpp +++ b/clang/test/SemaCXX/lambda-pack-expansion.cpp @@ -68,3 +68,25 @@ void f() { } } + +namespace GH61460 { + +template<typename... Ts> +void f1(Ts... ts); + +template <typename... Ts> void g(Ts... p1s) { + (void)[&](auto... p2s) { + ( + [&] { + p1s; + f1(p1s); + sizeof(p1s); + p2s; + }, + ...); + }; +} + +void f1() { g(); } + +} // namespace GH61460 diff --git a/clang/test/SemaCXX/pr61460.cpp b/clang/test/SemaCXX/pr61460.cpp deleted file mode 100644 index 471b1b39d23c2b..00000000000000 --- a/clang/test/SemaCXX/pr61460.cpp +++ /dev/null @@ -1,13 +0,0 @@ -// RUN: %clang_cc1 -std=c++17 %s -fsyntax-only -verify - -template <typename... Ts> void g(Ts... p1s) { - (void)[&](auto... p2s) { ([&] { p1s; p2s; }, ...); }; -} - -void f1() { - g(); -} - -template <typename... Ts> void g2(Ts... p1s) { - (void)[&](auto... p2s) { [&] { p1s; p2s; }; }; // expected-error {{expression contains unexpanded parameter pack 'p2s'}} -} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
