https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119962
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- libstdc++: [[no_unique_address]] __detail::__maybe_present_t<forward_range<_Vp>, iterator_t<_Base>> _M_current; vs libc++: using _MaybeCurrent [[__gnu__::__nodebug__]] = _If<forward_range<_View>, iterator_t<_Base>, __empty_cache>; [[__no_unique_address__]] _MaybeCurrent __current_ = _MaybeCurrent();