https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85821
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- Created attachment 45967 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45967&action=edit Implement standard-conforming signatures when GNU extensions are disabled This patch would fix your testcase, but at the expense of failing to meet a different (arguably more useful) requirement. This is https://wg21.link/lwg2383 and I don't think we want to make this change.