https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124447
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- Using reflection on anything inside namespace std is supposed to be unspecified, so that implementations are free to use equivalent techniques, e.g. defining a new alias vs redeclaring an existing one with a using-declaration. I don't think we want to change anything in namespace std just because reflection allows you to observe implementation details. I think we might need a clarification to [namespace.std] so that it also applies to typedefs and all other entities in std. And maybe also to names outside std that come from C, because programs should be relying on ::int64_t being defined any particular way. I think this bug is INVALID.
