[Bug c++/125425] undiagnosed maybe_unused attribute on static data member

[pinskia at gcc dot gnu.org]

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.