+ constexpr _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
+ : _Inherited(_Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
+ _Base(_Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
+
+ template<typename _UHead, typename... _UTails>
+ constexpr _Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
+ : _Inherited(std::move
+ (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
+ _Base(std::forward<_UHead>
+ (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
+
+ template<typename _Alloc>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
+ : _Inherited(__tag, __a),
+ _Base(__use_alloc<_Head>(__a)) { }
+
+ template<typename _Alloc>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ const _Head& __head, const _Tail&... __tail)
+ : _Inherited(__tag, __a, __tail...),
+ _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head) { }
+
+ template<typename _Alloc, typename _UHead, typename... _UTail,
+ typename = typename enable_if<sizeof...(_Tail)
+ == sizeof...(_UTail)>::type>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ _UHead&& __head, _UTail&&... __tail)
+ : _Inherited(__tag, __a, std::forward<_UTail>(__tail)...),
+ _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+ std::forward<_UHead>(__head)) { }
+
+ template<typename _Alloc>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ const _Tuple_impl& __in)
+ : _Inherited(__tag, __a, _M_tail(__in)),
+ _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in)) { }
+
+ template<typename _Alloc>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ _Tuple_impl&& __in)
+ : _Inherited(__tag, __a, std::move(_M_tail(__in))),
+ _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
+ std::forward<_Head>(_M_head(__in))) { }
+
+ template<typename _Alloc, typename... _UElements>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ const _Tuple_impl<_Idx, _UElements...>& __in)
+ : _Inherited(__tag, __a,
+ _Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
+ _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
+ _Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
+
+ template<typename _Alloc, typename _UHead, typename... _UTails>
+ _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+ _Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
+ : _Inherited(__tag, __a, std::move
+ (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
+ _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+ std::forward<_UHead>
+ (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }