https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94569
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- Both bugs are violations of [dcl.align] p5 though. The bug is not that GCC doesn't follow [basic.align] p1 (it does) but that it allows alignas to weaken the alignment later. GCC should not allow alignas to weaken alignment on any declaration, whether a class declaration or variable declaration, and that's PR 65685. I've added a more complete testcase there, which includes alignas on object declarations.