warn_for_different_enum_types
warn_for_different_enum_types (old->pos, old->ctype, type);
warn_for_different_enum_types(old->pos, old->ctype, type);
warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
warn_for_different_enum_types(right->pos, left->ctype, right->ctype);