https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65558
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Marek Polacek from comment #2) > If it is correct to ignore the abi_tag on an anonymous namespace It's correct, anything in an anon namespace cannot be named outside the current translation unit, so there's no point changing its mangling or warning about what happens when it's used by another TU.