https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85229
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed|2018-09-27 00:00:00 |2021-8-8 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So this is correctly rejected with -std=c++20 (even after removing the bool). With -std=c++17 -fconcepts this ICEs.