https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113294
Patrick Palka <ppalka at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2024-01-23 Status|UNCONFIRMED |NEW Ever confirmed|0 |1 CC| |ppalka at gcc dot gnu.org --- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> --- The front end started rejecting the testcase (with libstdc++ 12, 13 and 14 headers) after the active union member change tracking improvements r14-4771. Clang also rejects the testcase with libstdc++ 13 headers, which points to this being a library bug unlike the other related PRs about constexpr std::string. Your proposed fix looks good to me.