https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125425
--- Comment #2 from Drea Pinski <pinskia at gcc dot gnu.org> --- Considering previous changes in this area (e.g. https://cplusplus.github.io/CWG/issues/2360.html and https://cplusplus.github.io/CWG/issues/2733.html) this looks like an oversight in the standard. Plus no major compiler warns makes it even more of an oversight.
