https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124621
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Ah, user_facing_original_type_p does
/* Look through any typedef in "user" code. */
if (!DECL_IN_SYSTEM_HEADER (decl) && !DECL_IS_UNDECLARED_BUILTIN (decl))
return true;
