https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114426
--- Comment #12 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:0fd824d717ca901319864a5eeba4e62b278f8329 commit r14-9942-g0fd824d717ca901319864a5eeba4e62b278f8329 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Apr 12 19:57:04 2024 +0200 c++: Diagnose or avoid constexpr dtors in classes with virtual bases [PR114426] I had another look at this P1 PR today. You said in the "c++: fix in-charge parm in constexpr" mail back in December (as well as in the r14-6507 commit message): "Since a class with vbases can't have constexpr 'tors there isn't actually a need for an in-charge parameter in a destructor" but the ICE is because the destructor is marked implicitly constexpr. https://eel.is/c++draft/dcl.constexpr#3.2 says that a destructor of a class with virtual bases is not constexpr-suitable, but we were actually implementing this just for constructors, so clearly my fault from the https://wg21.link/P0784R7 implementation. That paper clearly added that sentence in there and removed similar sentence just from the constructor case. So, the following patch makes sure the else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) { ret = false; if (complain) error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); } hunk is done no just for DECL_CONSTRUCTOR_P (fun), but also DECL_DESTRUCTOR_P (fun) - in that case just for cxx_dialect >= cxx20, as for cxx_dialect < cxx20 we already set ret = false; and diagnose a different error, so no need to diagnose two. 2024-04-12 Jakub Jelinek <ja...@redhat.com> PR c++/114426 * constexpr.cc (is_valid_constexpr_fn): Return false/diagnose with complain destructors in classes with virtual bases. * g++.dg/cpp2a/pr114426.C: New test. * g++.dg/cpp2a/constexpr-dtor16.C: New test.
