https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120300
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- >The handling of -Wmissing-noreturn should behave the same whether a member >function is defined in-class or out-of-class. The problem is Wmissing-noreturn happens after optimizations so if a function is defined in-class it has an implicit vague linkage and not included. I think there might be a dup of this.