https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109475
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- >but then some warnings despite being listed there were not triggered: https://godbolt.org/z/GGnjcjxKh You get the trigraph warning if you don't supply any options. -std=c++14 option enables -trigraphs option
