https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107981
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- https://wg21.link/CWG1670 makes this invalid.
[Bug c++/107981] 'operator auto' has not been declared in base
pinskia at gcc dot gnu.org via Gcc-bugs Wed, 10 Dec 2025 21:25:55 -0800
