https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101118
--- Comment #10 from Iain Sandoe <iains at gcc dot gnu.org> --- Hmm... maybe I am being too hasty here. If the coroutine has a definition in a header, then the coroutine frame type _should_ be the same for each instance of it. So maybe this is actually reporting a genuine ODR violation?