https://github.com/arrowten created https://github.com/llvm/llvm-project/pull/203715
When rebuilding a CXXFunctionalCastExpr during template instantiation, where the sub-expression is a CXXParenListInitExpr, we were passing all stored initializers to BuildCXXTypeConstructExpr — including the ones the compiler synthesized for uninitialized aggregate fields. Only the user-written initializers should be passed, otherwise we hit an assertion. The test cases might be incomplete. I would like suggestions on what more type of testcases to be added. Fixes #194986 >From 7bb116a9b11ea3775d67defb41e27674122e94b1 Mon Sep 17 00:00:00 2001 From: Ajay Wakodikar <[email protected]> Date: Sat, 13 Jun 2026 12:49:23 -0400 Subject: [PATCH] [Sema] Fix assertion in TreeTransform when rebuilding CXXParenListInitExpr --- clang/lib/Sema/TreeTransform.h | 6 +++++- .../test/SemaCXX/paren-agg-init-template-rebuild.cpp | 12 ++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) create mode 100644 clang/test/SemaCXX/paren-agg-init-template-rebuild.cpp diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h index 53107c827006d..e475041026dc8 100644 --- a/clang/lib/Sema/TreeTransform.h +++ b/clang/lib/Sema/TreeTransform.h @@ -3410,9 +3410,13 @@ class TreeTransform { TInfo, LParenLoc, MultiExprArg(PLE->getExprs(), PLE->getNumExprs()), RParenLoc, ListInitialization); + // Skip compiler-added exprs — only pass what the user actually wrote, + // or we get false "too many initializers" errors. if (auto *PLE = dyn_cast<CXXParenListInitExpr>(Sub)) return getSema().BuildCXXTypeConstructExpr( - TInfo, LParenLoc, PLE->getInitExprs(), RParenLoc, ListInitialization); + TInfo, LParenLoc, + PLE->getInitExprs().slice(0, PLE->getUserSpecifiedInitExprs().size()), + RParenLoc, ListInitialization); return getSema().BuildCXXTypeConstructExpr(TInfo, LParenLoc, MultiExprArg(&Sub, 1), RParenLoc, diff --git a/clang/test/SemaCXX/paren-agg-init-template-rebuild.cpp b/clang/test/SemaCXX/paren-agg-init-template-rebuild.cpp new file mode 100644 index 0000000000000..9ac9d9fe797bb --- /dev/null +++ b/clang/test/SemaCXX/paren-agg-init-template-rebuild.cpp @@ -0,0 +1,12 @@ +// RUN: %clang_cc1 -verify -std=c++23 %s -fsyntax-only + +struct S {}; // expected-note 2{{candidate constructor}} +template <typename T> struct SS { T t1; T t2; }; +template <class T, class... Args> T C(Args... args) { return SS("foo"); } // expected-error {{no viable conversion}} +S s = C<S>(); // expected-note {{in instantiation of function template specialization 'C<S>'}} + +template <class T> struct SS2 { T t1, t2; }; +template <class> void C2() { + SS2("foo"); // expected-warning 2{{expression result unused}} +} +template void C2<int>(); // expected-note {{in instantiation of function template specialization 'C2<int>'}} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
