https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108309
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to tim blechmann from comment #3) > > That is a conditionally supported construct in C++. clang does not support > > it but GCC does. > > > > GCC does warn with -Wconditionally-supported > > interesting. i may have to reduce it manually rather than going through > cvise: the real-world code builds with clang and gcc doesn't seem to emit a > warning with -Wconditionally-supported Or you could add -Werror=conditionally-supported as an option and reduce it that way ...