https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108587
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Yes and gcc is correct here. Even if you did: typedef int t; struct s{ typedef t t; }; This code is illform but no diagnostic is required. Gcc is one of the few compilers which does the diagnostic for it.