http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60761
--- Comment #1 from Martin Jambor <jamborm at gcc dot gnu.org> --- This is because in dump_decl in gcc/cp/error.c there is: case FUNCTION_DECL: if (! DECL_LANG_SPECIFIC (t)) pp_string (pp, M_("<built-in>")); and the revision causing this clears DECL_LANG_SPECIFIC.