126    class tuple;
161     class tuple : public _Tuple_impl<0, _Elements...>  class
168         constexpr tuple(_UElements&&... __elements)  in tuple()  function in std::tuple
182     struct tuple_element<__i, tuple<_Head, _Tail...> >
183     : tuple_element<__i - 1, tuple<_Tail...> > { };
189     struct tuple_element<0, tuple<_Head, _Tail...> >
211                       typename tuple_element<__i, tuple<_Elements...>>::type
213     get(const tuple<_Elements...>& __t) noexcept  in get()
218     tuple<_Elements&&...>
220     { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }  in forward_as_tuple()
234     tuple<_Elements&&...>
236 { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }  in my_forward_as_tuple()