xref: /netbsd-src/external/apache2/llvm/dist/libcxx/include/tuple (revision 4d6fc14bc9b0c5bf3e30be318c143ee82cadd108) 
1// -*- C++ -*-
2//===--------------------------- tuple ------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_TUPLE
11#define _LIBCPP_TUPLE
12
13/*
14    tuple synopsis
15
16namespace std
17{
18
19template <class... T>
20class tuple {
21public:
22    explicit(see-below) constexpr tuple();
23    explicit(see-below) tuple(const T&...);  // constexpr in C++14
24    template <class... U>
25        explicit(see-below) tuple(U&&...);  // constexpr in C++14
26    tuple(const tuple&) = default;
27    tuple(tuple&&) = default;
28    template <class... U>
29        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
30    template <class... U>
31        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
32    template <class U1, class U2>
33        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
34    template <class U1, class U2>
35        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
36
37    // allocator-extended constructors
38    template <class Alloc>
39        tuple(allocator_arg_t, const Alloc& a);
40    template <class Alloc>
41        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
42    template <class Alloc, class... U>
43        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
44    template <class Alloc>
45        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
46    template <class Alloc>
47        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
48    template <class Alloc, class... U>
49        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
50    template <class Alloc, class... U>
51        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
52    template <class Alloc, class U1, class U2>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
54    template <class Alloc, class U1, class U2>
55        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
56
57    tuple& operator=(const tuple&);                                                       // constexpr in C++20
58    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
59    template <class... U>
60        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
61    template <class... U>
62        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
63    template <class U1, class U2>
64        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
65    template <class U1, class U2>
66        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
67
68    template<class U, size_t N>
69        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
70    template<class U, size_t N>
71        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
72
73    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
74};
75
76template <class ...T>
77tuple(T...) -> tuple<T...>;                                         // since C++17
78template <class T1, class T2>
79tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
80template <class Alloc, class ...T>
81tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
82template <class Alloc, class T1, class T2>
83tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
84template <class Alloc, class ...T>
85tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
86
87inline constexpr unspecified ignore;
88
89template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
90template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
91template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
92template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
93
94// [tuple.apply], calling a function with a tuple of arguments:
95template <class F, class Tuple>
96  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
97template <class T, class Tuple>
98  constexpr T make_from_tuple(Tuple&& t); // C++17
99
100// 20.4.1.4, tuple helper classes:
101template <class T> struct tuple_size; // undefined
102template <class... T> struct tuple_size<tuple<T...>>;
103template <class T>
104 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
105template <size_t I, class T> struct tuple_element; // undefined
106template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
107template <size_t I, class T>
108  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
109
110// 20.4.1.5, element access:
111template <size_t I, class... T>
112    typename tuple_element<I, tuple<T...>>::type&
113    get(tuple<T...>&) noexcept; // constexpr in C++14
114template <size_t I, class... T>
115    const typename tuple_element<I, tuple<T...>>::type&
116    get(const tuple<T...>&) noexcept; // constexpr in C++14
117template <size_t I, class... T>
118    typename tuple_element<I, tuple<T...>>::type&&
119    get(tuple<T...>&&) noexcept; // constexpr in C++14
120template <size_t I, class... T>
121    const typename tuple_element<I, tuple<T...>>::type&&
122    get(const tuple<T...>&&) noexcept; // constexpr in C++14
123
124template <class T1, class... T>
125    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
126template <class T1, class... T>
127    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
128template <class T1, class... T>
129    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
130template <class T1, class... T>
131    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
132
133// 20.4.1.6, relational operators:
134template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
135template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
136template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
137template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
138template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
139template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
140
141template <class... Types, class Alloc>
142  struct uses_allocator<tuple<Types...>, Alloc>;
143
144template <class... Types>
145  void
146  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
147
148}  // std
149
150*/
151
152#include <__config>
153#include <__tuple>
154#include <compare>
155#include <cstddef>
156#include <type_traits>
157#include <__functional_base>
158#include <utility>
159#include <version>
160
161#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
162#pragma GCC system_header
163#endif
164
165_LIBCPP_BEGIN_NAMESPACE_STD
166
167#ifndef _LIBCPP_CXX03_LANG
168
169
170// __tuple_leaf
171
172template <size_t _Ip, class _Hp,
173          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
174         >
175class __tuple_leaf;
176
177template <size_t _Ip, class _Hp, bool _Ep>
178inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
179void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
180    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
181{
182    swap(__x.get(), __y.get());
183}
184
185template <size_t _Ip, class _Hp, bool>
186class __tuple_leaf
187{
188    _Hp __value_;
189
190    template <class _Tp>
191    static constexpr bool __can_bind_reference() {
192#if __has_keyword(__reference_binds_to_temporary)
193      return !__reference_binds_to_temporary(_Hp, _Tp);
194#else
195      return true;
196#endif
197    }
198
199    _LIBCPP_CONSTEXPR_AFTER_CXX11
200    __tuple_leaf& operator=(const __tuple_leaf&);
201public:
202    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
203             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
204       {static_assert(!is_reference<_Hp>::value,
205              "Attempted to default construct a reference element in a tuple");}
206
207    template <class _Alloc>
208        _LIBCPP_INLINE_VISIBILITY constexpr
209        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
210            : __value_()
211        {static_assert(!is_reference<_Hp>::value,
212              "Attempted to default construct a reference element in a tuple");}
213
214    template <class _Alloc>
215        _LIBCPP_INLINE_VISIBILITY constexpr
216        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
217            : __value_(allocator_arg_t(), __a)
218        {static_assert(!is_reference<_Hp>::value,
219              "Attempted to default construct a reference element in a tuple");}
220
221    template <class _Alloc>
222        _LIBCPP_INLINE_VISIBILITY constexpr
223        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
224            : __value_(__a)
225        {static_assert(!is_reference<_Hp>::value,
226              "Attempted to default construct a reference element in a tuple");}
227
228    template <class _Tp,
229              class = _EnableIf<
230                  _And<
231                      _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
232                      is_constructible<_Hp, _Tp>
233                    >::value
234                >
235            >
236        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
237        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
238            : __value_(_VSTD::forward<_Tp>(__t))
239        {static_assert(__can_bind_reference<_Tp&&>(),
240       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
241
242    template <class _Tp, class _Alloc>
243        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
244        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
245            : __value_(_VSTD::forward<_Tp>(__t))
246        {static_assert(__can_bind_reference<_Tp&&>(),
247       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
248
249    template <class _Tp, class _Alloc>
250        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
251        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
252            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
253        {static_assert(!is_reference<_Hp>::value,
254            "Attempted to uses-allocator construct a reference element in a tuple");}
255
256    template <class _Tp, class _Alloc>
257        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
258        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
259            : __value_(_VSTD::forward<_Tp>(__t), __a)
260        {static_assert(!is_reference<_Hp>::value,
261           "Attempted to uses-allocator construct a reference element in a tuple");}
262
263    __tuple_leaf(const __tuple_leaf& __t) = default;
264    __tuple_leaf(__tuple_leaf&& __t) = default;
265
266    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
267    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
268    {
269        _VSTD::swap(*this, __t);
270        return 0;
271    }
272
273    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return __value_;}
274    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return __value_;}
275};
276
277template <size_t _Ip, class _Hp>
278class __tuple_leaf<_Ip, _Hp, true>
279    : private _Hp
280{
281    _LIBCPP_CONSTEXPR_AFTER_CXX11
282    __tuple_leaf& operator=(const __tuple_leaf&);
283public:
284    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
285             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
286
287    template <class _Alloc>
288        _LIBCPP_INLINE_VISIBILITY constexpr
289        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
290
291    template <class _Alloc>
292        _LIBCPP_INLINE_VISIBILITY constexpr
293        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
294            : _Hp(allocator_arg_t(), __a) {}
295
296    template <class _Alloc>
297        _LIBCPP_INLINE_VISIBILITY constexpr
298        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
299            : _Hp(__a) {}
300
301    template <class _Tp,
302              class = _EnableIf<
303                  _And<
304                    _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
305                    is_constructible<_Hp, _Tp>
306                  >::value
307                >
308            >
309        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
310        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
311            : _Hp(_VSTD::forward<_Tp>(__t)) {}
312
313    template <class _Tp, class _Alloc>
314        _LIBCPP_INLINE_VISIBILITY constexpr
315        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
316            : _Hp(_VSTD::forward<_Tp>(__t)) {}
317
318    template <class _Tp, class _Alloc>
319        _LIBCPP_INLINE_VISIBILITY constexpr
320        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
321            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
322
323    template <class _Tp, class _Alloc>
324        _LIBCPP_INLINE_VISIBILITY constexpr
325        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
326            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
327
328    __tuple_leaf(__tuple_leaf const &) = default;
329    __tuple_leaf(__tuple_leaf &&) = default;
330
331    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
332    int
333    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
334    {
335        _VSTD::swap(*this, __t);
336        return 0;
337    }
338
339    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
340    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
341};
342
343template <class ..._Tp>
344_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
345void __swallow(_Tp&&...) _NOEXCEPT {}
346
347template <class _Tp>
348struct __all_default_constructible;
349
350template <class ..._Tp>
351struct __all_default_constructible<__tuple_types<_Tp...>>
352    : __all<is_default_constructible<_Tp>::value...>
353{ };
354
355// __tuple_impl
356
357template<class _Indx, class ..._Tp> struct __tuple_impl;
358
359template<size_t ..._Indx, class ..._Tp>
360struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
361    : public __tuple_leaf<_Indx, _Tp>...
362{
363    _LIBCPP_INLINE_VISIBILITY
364    constexpr __tuple_impl()
365        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
366
367    template <size_t ..._Uf, class ..._Tf,
368              size_t ..._Ul, class ..._Tl, class ..._Up>
369        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
370        explicit
371        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
372                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
373                     _Up&&... __u)
374                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
375                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
376            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
377            __tuple_leaf<_Ul, _Tl>()...
378            {}
379
380    template <class _Alloc, size_t ..._Uf, class ..._Tf,
381              size_t ..._Ul, class ..._Tl, class ..._Up>
382        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
383        explicit
384        __tuple_impl(allocator_arg_t, const _Alloc& __a,
385                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
386                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
387                     _Up&&... __u) :
388            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
389            _VSTD::forward<_Up>(__u))...,
390            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
391            {}
392
393    template <class _Tuple,
394              class = typename enable_if
395                      <
396                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
397                      >::type
398             >
399        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
400        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
401                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
402            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
403                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
404            {}
405
406    template <class _Alloc, class _Tuple,
407              class = typename enable_if
408                      <
409                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
410                      >::type
411             >
412        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
413        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
414            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
415                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
416                                       _VSTD::forward<typename tuple_element<_Indx,
417                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
418            {}
419
420    __tuple_impl(const __tuple_impl&) = default;
421    __tuple_impl(__tuple_impl&&) = default;
422
423    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
424    void swap(__tuple_impl& __t)
425        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
426    {
427        _VSTD::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
428    }
429};
430
431template<class _Dest, class _Source, size_t ..._Np>
432_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
433void __memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
434    _VSTD::__swallow(((_VSTD::get<_Np>(__dest) = _VSTD::get<_Np>(__source)), void(), 0)...);
435}
436
437template<class _Dest, class _Source, class ..._Up, size_t ..._Np>
438_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
439void __memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
440    _VSTD::__swallow(((
441        _VSTD::get<_Np>(__dest) = _VSTD::forward<_Up>(_VSTD::get<_Np>(__source))
442    ), void(), 0)...);
443}
444
445template <class ..._Tp>
446class _LIBCPP_TEMPLATE_VIS tuple
447{
448    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
449
450    _BaseT __base_;
451
452    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
453        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
454    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
455        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
456    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
457        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
458    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
459        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
460public:
461    // [tuple.cnstr]
462
463    // tuple() constructors (including allocator_arg_t variants)
464    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible, _EnableIf<
465        _And<
466            _IsImpDefault<_Tp>... // explicit check
467        >::value
468    , int> = 0>
469    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
470    tuple()
471        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
472    { }
473
474    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
475              template<class...> class _IsDefault = is_default_constructible, _EnableIf<
476        _And<
477            _IsDefault<_Tp>...,
478            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
479        >::value
480    , int> = 0>
481    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
482    explicit tuple()
483        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
484    { }
485
486    template <class _Alloc, template<class...> class _IsImpDefault = __is_implicitly_default_constructible, _EnableIf<
487        _And<
488            _IsImpDefault<_Tp>... // explicit check
489        >::value
490    , int> = 0>
491    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
492    tuple(allocator_arg_t, _Alloc const& __a)
493      : __base_(allocator_arg_t(), __a,
494                    __tuple_indices<>(), __tuple_types<>(),
495                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
496                    __tuple_types<_Tp...>()) {}
497
498    template <class _Alloc,
499              template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
500              template<class...> class _IsDefault = is_default_constructible, _EnableIf<
501        _And<
502            _IsDefault<_Tp>...,
503            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
504        >::value
505    , int> = 0>
506    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
507    explicit tuple(allocator_arg_t, _Alloc const& __a)
508      : __base_(allocator_arg_t(), __a,
509                    __tuple_indices<>(), __tuple_types<>(),
510                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
511                    __tuple_types<_Tp...>()) {}
512
513    // tuple(const T&...) constructors (including allocator_arg_t variants)
514    template <template<class...> class _And = _And, _EnableIf<
515        _And<
516            _BoolConstant<sizeof...(_Tp) >= 1>,
517            is_copy_constructible<_Tp>...,
518            is_convertible<const _Tp&, _Tp>... // explicit check
519        >::value
520    , int> = 0>
521    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
522    tuple(const _Tp& ... __t)
523        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
524        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
525                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
526                typename __make_tuple_indices<0>::type(),
527                typename __make_tuple_types<tuple, 0>::type(),
528                __t...
529               ) {}
530
531    template <template<class...> class _And = _And, _EnableIf<
532        _And<
533            _BoolConstant<sizeof...(_Tp) >= 1>,
534            is_copy_constructible<_Tp>...,
535            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
536        >::value
537    , int> = 0>
538    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
539    explicit tuple(const _Tp& ... __t)
540        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
541        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
542                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
543                typename __make_tuple_indices<0>::type(),
544                typename __make_tuple_types<tuple, 0>::type(),
545                __t...
546               ) {}
547
548    template <class _Alloc, template<class...> class _And = _And, _EnableIf<
549        _And<
550            _BoolConstant<sizeof...(_Tp) >= 1>,
551            is_copy_constructible<_Tp>...,
552            is_convertible<const _Tp&, _Tp>... // explicit check
553        >::value
554    , int> = 0>
555    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
556    tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
557        : __base_(allocator_arg_t(), __a,
558                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
559                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
560                typename __make_tuple_indices<0>::type(),
561                typename __make_tuple_types<tuple, 0>::type(),
562                __t...
563               ) {}
564
565    template <class _Alloc, template<class...> class _And = _And, _EnableIf<
566        _And<
567            _BoolConstant<sizeof...(_Tp) >= 1>,
568            is_copy_constructible<_Tp>...,
569            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
570        >::value
571    , int> = 0>
572    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
573    explicit tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
574        : __base_(allocator_arg_t(), __a,
575                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
576                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
577                typename __make_tuple_indices<0>::type(),
578                typename __make_tuple_types<tuple, 0>::type(),
579                __t...
580               ) {}
581
582    // tuple(U&& ...) constructors (including allocator_arg_t variants)
583    template <class ..._Up> struct _IsThisTuple : false_type { };
584    template <class _Up> struct _IsThisTuple<_Up> : is_same<__uncvref_t<_Up>, tuple> { };
585
586    template <class ..._Up>
587    struct _EnableUTypesCtor : _And<
588        _BoolConstant<sizeof...(_Tp) >= 1>,
589        _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
590        is_constructible<_Tp, _Up>...
591    > { };
592
593    template <class ..._Up, _EnableIf<
594        _And<
595            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
596            _EnableUTypesCtor<_Up...>,
597            is_convertible<_Up, _Tp>... // explicit check
598        >::value
599    , int> = 0>
600    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
601    tuple(_Up&&... __u)
602        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
603        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
604                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
605                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
606                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
607                    _VSTD::forward<_Up>(__u)...) {}
608
609    template <class ..._Up, _EnableIf<
610        _And<
611            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
612            _EnableUTypesCtor<_Up...>,
613            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
614        >::value
615    , int> = 0>
616    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
617    explicit tuple(_Up&&... __u)
618        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
619        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
620                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
621                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
622                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
623                    _VSTD::forward<_Up>(__u)...) {}
624
625    template <class _Alloc, class ..._Up, _EnableIf<
626        _And<
627            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
628            _EnableUTypesCtor<_Up...>,
629            is_convertible<_Up, _Tp>... // explicit check
630        >::value
631    , int> = 0>
632    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
633    tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
634        : __base_(allocator_arg_t(), __a,
635                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
636                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
637                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
638                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
639                    _VSTD::forward<_Up>(__u)...) {}
640
641    template <class _Alloc, class ..._Up, _EnableIf<
642        _And<
643            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
644            _EnableUTypesCtor<_Up...>,
645            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
646        >::value
647    , int> = 0>
648    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
649    explicit tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
650        : __base_(allocator_arg_t(), __a,
651                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
652                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
653                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
654                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
655                    _VSTD::forward<_Up>(__u)...) {}
656
657    // Copy and move constructors (including the allocator_arg_t variants)
658    tuple(const tuple&) = default;
659    tuple(tuple&&) = default;
660
661    template <class _Alloc, template<class...> class _And = _And, _EnableIf<
662        _And<is_copy_constructible<_Tp>...>::value
663    , int> = 0>
664    tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
665        : __base_(allocator_arg_t(), __alloc, __t)
666    { }
667
668    template <class _Alloc, template<class...> class _And = _And, _EnableIf<
669        _And<is_move_constructible<_Tp>...>::value
670    , int> = 0>
671    tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
672        : __base_(allocator_arg_t(), __alloc, _VSTD::move(__t))
673    { }
674
675    // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
676    template <class ..._Up>
677    struct _EnableCopyFromOtherTuple : _And<
678        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
679        _Lazy<_Or,
680            _BoolConstant<sizeof...(_Tp) != 1>,
681            // _Tp and _Up are 1-element packs - the pack expansions look
682            // weird to avoid tripping up the type traits in degenerate cases
683            _Lazy<_And,
684                _Not<is_convertible<const tuple<_Up>&, _Tp> >...,
685                _Not<is_constructible<_Tp, const tuple<_Up>&> >...
686            >
687        >,
688        is_constructible<_Tp, const _Up&>...
689    > { };
690
691    template <class ..._Up, _EnableIf<
692        _And<
693            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
694            _EnableCopyFromOtherTuple<_Up...>,
695            is_convertible<const _Up&, _Tp>... // explicit check
696        >::value
697    , int> = 0>
698    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
699    tuple(const tuple<_Up...>& __t)
700        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
701        : __base_(__t)
702    { }
703
704    template <class ..._Up, _EnableIf<
705        _And<
706            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
707            _EnableCopyFromOtherTuple<_Up...>,
708            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
709        >::value
710    , int> = 0>
711    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
712    explicit tuple(const tuple<_Up...>& __t)
713        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
714        : __base_(__t)
715    { }
716
717    template <class ..._Up, class _Alloc, _EnableIf<
718        _And<
719            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
720            _EnableCopyFromOtherTuple<_Up...>,
721            is_convertible<const _Up&, _Tp>... // explicit check
722        >::value
723    , int> = 0>
724    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
725    tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
726        : __base_(allocator_arg_t(), __a, __t)
727    { }
728
729    template <class ..._Up, class _Alloc, _EnableIf<
730        _And<
731            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
732            _EnableCopyFromOtherTuple<_Up...>,
733            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
734        >::value
735    , int> = 0>
736    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
737    explicit tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
738        : __base_(allocator_arg_t(), __a, __t)
739    { }
740
741    // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
742    template <class ..._Up>
743    struct _EnableMoveFromOtherTuple : _And<
744        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
745        _Lazy<_Or,
746            _BoolConstant<sizeof...(_Tp) != 1>,
747            // _Tp and _Up are 1-element packs - the pack expansions look
748            // weird to avoid tripping up the type traits in degenerate cases
749            _Lazy<_And,
750                _Not<is_convertible<tuple<_Up>, _Tp> >...,
751                _Not<is_constructible<_Tp, tuple<_Up> > >...
752            >
753        >,
754        is_constructible<_Tp, _Up>...
755    > { };
756
757    template <class ..._Up, _EnableIf<
758        _And<
759            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
760            _EnableMoveFromOtherTuple<_Up...>,
761            is_convertible<_Up, _Tp>... // explicit check
762        >::value
763    , int> = 0>
764    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
765    tuple(tuple<_Up...>&& __t)
766        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
767        : __base_(_VSTD::move(__t))
768    { }
769
770    template <class ..._Up, _EnableIf<
771        _And<
772            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
773            _EnableMoveFromOtherTuple<_Up...>,
774            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
775        >::value
776    , int> = 0>
777    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
778    explicit tuple(tuple<_Up...>&& __t)
779        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
780        : __base_(_VSTD::move(__t))
781    { }
782
783    template <class _Alloc, class ..._Up, _EnableIf<
784        _And<
785            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
786            _EnableMoveFromOtherTuple<_Up...>,
787            is_convertible<_Up, _Tp>... // explicit check
788        >::value
789    , int> = 0>
790    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
791    tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
792        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
793    { }
794
795    template <class _Alloc, class ..._Up, _EnableIf<
796        _And<
797            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
798            _EnableMoveFromOtherTuple<_Up...>,
799            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
800        >::value
801    , int> = 0>
802    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
803    explicit tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
804        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
805    { }
806
807    // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
808    template <class _Up1, class _Up2, class ..._DependentTp>
809    struct _EnableImplicitCopyFromPair : _And<
810        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
811        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
812        is_convertible<const _Up1&, _FirstType<_DependentTp...> >, // explicit check
813        is_convertible<const _Up2&, _SecondType<_DependentTp...> >
814    > { };
815
816    template <class _Up1, class _Up2, class ..._DependentTp>
817    struct _EnableExplicitCopyFromPair : _And<
818        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
819        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
820        _Not<is_convertible<const _Up1&, _FirstType<_DependentTp...> > >, // explicit check
821        _Not<is_convertible<const _Up2&, _SecondType<_DependentTp...> > >
822    > { };
823
824    template <class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
825        _And<
826            _BoolConstant<sizeof...(_Tp) == 2>,
827            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
828        >::value
829    , int> = 0>
830    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
831    tuple(const pair<_Up1, _Up2>& __p)
832        _NOEXCEPT_((_And<
833            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
834            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
835        >::value))
836        : __base_(__p)
837    { }
838
839    template <class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
840        _And<
841            _BoolConstant<sizeof...(_Tp) == 2>,
842            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
843        >::value
844    , int> = 0>
845    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
846    explicit tuple(const pair<_Up1, _Up2>& __p)
847        _NOEXCEPT_((_And<
848            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
849            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
850        >::value))
851        : __base_(__p)
852    { }
853
854    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
855        _And<
856            _BoolConstant<sizeof...(_Tp) == 2>,
857            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
858        >::value
859    , int> = 0>
860    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
861    tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
862        : __base_(allocator_arg_t(), __a, __p)
863    { }
864
865    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
866        _And<
867            _BoolConstant<sizeof...(_Tp) == 2>,
868            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
869        >::value
870    , int> = 0>
871    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
872    explicit tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
873        : __base_(allocator_arg_t(), __a, __p)
874    { }
875
876    // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
877    template <class _Up1, class _Up2, class ..._DependentTp>
878    struct _EnableImplicitMoveFromPair : _And<
879        is_constructible<_FirstType<_DependentTp...>, _Up1>,
880        is_constructible<_SecondType<_DependentTp...>, _Up2>,
881        is_convertible<_Up1, _FirstType<_DependentTp...> >, // explicit check
882        is_convertible<_Up2, _SecondType<_DependentTp...> >
883    > { };
884
885    template <class _Up1, class _Up2, class ..._DependentTp>
886    struct _EnableExplicitMoveFromPair : _And<
887        is_constructible<_FirstType<_DependentTp...>, _Up1>,
888        is_constructible<_SecondType<_DependentTp...>, _Up2>,
889        _Not<is_convertible<_Up1, _FirstType<_DependentTp...> > >, // explicit check
890        _Not<is_convertible<_Up2, _SecondType<_DependentTp...> > >
891    > { };
892
893    template <class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
894        _And<
895            _BoolConstant<sizeof...(_Tp) == 2>,
896            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
897        >::value
898    , int> = 0>
899    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
900    tuple(pair<_Up1, _Up2>&& __p)
901        _NOEXCEPT_((_And<
902            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
903            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
904        >::value))
905        : __base_(_VSTD::move(__p))
906    { }
907
908    template <class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
909        _And<
910            _BoolConstant<sizeof...(_Tp) == 2>,
911            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
912        >::value
913    , int> = 0>
914    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
915    explicit tuple(pair<_Up1, _Up2>&& __p)
916        _NOEXCEPT_((_And<
917            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
918            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
919        >::value))
920        : __base_(_VSTD::move(__p))
921    { }
922
923    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
924        _And<
925            _BoolConstant<sizeof...(_Tp) == 2>,
926            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
927        >::value
928    , int> = 0>
929    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
930    tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
931        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
932    { }
933
934    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, _EnableIf<
935        _And<
936            _BoolConstant<sizeof...(_Tp) == 2>,
937            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
938        >::value
939    , int> = 0>
940    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
941    explicit tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
942        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
943    { }
944
945    // [tuple.assign]
946    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
947    tuple& operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
948        _NOEXCEPT_((_And<is_nothrow_copy_assignable<_Tp>...>::value))
949    {
950        _VSTD::__memberwise_copy_assign(*this, __tuple,
951            typename __make_tuple_indices<sizeof...(_Tp)>::type());
952        return *this;
953    }
954
955    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
956    tuple& operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
957        _NOEXCEPT_((_And<is_nothrow_move_assignable<_Tp>...>::value))
958    {
959        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
960            __tuple_types<_Tp...>(),
961            typename __make_tuple_indices<sizeof...(_Tp)>::type());
962        return *this;
963    }
964
965    template<class... _Up, _EnableIf<
966        _And<
967            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
968            is_assignable<_Tp&, _Up const&>...
969        >::value
970    ,int> = 0>
971    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
972    tuple& operator=(tuple<_Up...> const& __tuple)
973        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
974    {
975        _VSTD::__memberwise_copy_assign(*this, __tuple,
976            typename __make_tuple_indices<sizeof...(_Tp)>::type());
977        return *this;
978    }
979
980    template<class... _Up, _EnableIf<
981        _And<
982            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
983            is_assignable<_Tp&, _Up>...
984        >::value
985    ,int> = 0>
986    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
987    tuple& operator=(tuple<_Up...>&& __tuple)
988        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
989    {
990        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
991            __tuple_types<_Up...>(),
992            typename __make_tuple_indices<sizeof...(_Tp)>::type());
993        return *this;
994    }
995
996    template<class _Up1, class _Up2, class _Dep = true_type, _EnableIf<
997        _And<_Dep,
998            _BoolConstant<sizeof...(_Tp) == 2>,
999            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1 const&>,
1000            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2 const&>
1001        >::value
1002    ,int> = 0>
1003    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1004    tuple& operator=(pair<_Up1, _Up2> const& __pair)
1005        _NOEXCEPT_((_And<
1006            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1 const&>,
1007            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2 const&>
1008        >::value))
1009    {
1010        _VSTD::get<0>(*this) = __pair.first;
1011        _VSTD::get<1>(*this) = __pair.second;
1012        return *this;
1013    }
1014
1015    template<class _Up1, class _Up2, class _Dep = true_type, _EnableIf<
1016        _And<_Dep,
1017            _BoolConstant<sizeof...(_Tp) == 2>,
1018            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1>,
1019            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2>
1020        >::value
1021    ,int> = 0>
1022    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1023    tuple& operator=(pair<_Up1, _Up2>&& __pair)
1024        _NOEXCEPT_((_And<
1025            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1>,
1026            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2>
1027        >::value))
1028    {
1029        _VSTD::get<0>(*this) = _VSTD::forward<_Up1>(__pair.first);
1030        _VSTD::get<1>(*this) = _VSTD::forward<_Up2>(__pair.second);
1031        return *this;
1032    }
1033
1034    // EXTENSION
1035    template<class _Up, size_t _Np, class = _EnableIf<
1036        _And<
1037            _BoolConstant<_Np == sizeof...(_Tp)>,
1038            is_assignable<_Tp&, _Up const&>...
1039        >::value
1040    > >
1041    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1042    tuple& operator=(array<_Up, _Np> const& __array)
1043        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
1044    {
1045        _VSTD::__memberwise_copy_assign(*this, __array,
1046            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1047        return *this;
1048    }
1049
1050    // EXTENSION
1051    template<class _Up, size_t _Np, class = void, class = _EnableIf<
1052        _And<
1053            _BoolConstant<_Np == sizeof...(_Tp)>,
1054            is_assignable<_Tp&, _Up>...
1055        >::value
1056    > >
1057    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1058    tuple& operator=(array<_Up, _Np>&& __array)
1059        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
1060    {
1061        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__array),
1062            __tuple_types<_If<true, _Up, _Tp>...>(),
1063            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1064        return *this;
1065    }
1066
1067    // [tuple.swap]
1068    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1069    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1070        {__base_.swap(__t.__base_);}
1071};
1072
1073template <>
1074class _LIBCPP_TEMPLATE_VIS tuple<>
1075{
1076public:
1077    _LIBCPP_INLINE_VISIBILITY constexpr
1078        tuple() _NOEXCEPT = default;
1079    template <class _Alloc>
1080    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1081        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1082    template <class _Alloc>
1083    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1084        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1085    template <class _Up>
1086    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1087        tuple(array<_Up, 0>) _NOEXCEPT {}
1088    template <class _Alloc, class _Up>
1089    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1090        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1091    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1092    void swap(tuple&) _NOEXCEPT {}
1093};
1094
1095#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
1096template <class ..._Tp>
1097tuple(_Tp...) -> tuple<_Tp...>;
1098template <class _Tp1, class _Tp2>
1099tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1100template <class _Alloc, class ..._Tp>
1101tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1102template <class _Alloc, class _Tp1, class _Tp2>
1103tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1104template <class _Alloc, class ..._Tp>
1105tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1106#endif
1107
1108template <class ..._Tp>
1109inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1110typename enable_if
1111<
1112    __all<__is_swappable<_Tp>::value...>::value,
1113    void
1114>::type
1115swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1116                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1117    {__t.swap(__u);}
1118
1119// get
1120
1121template <size_t _Ip, class ..._Tp>
1122inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1123typename tuple_element<_Ip, tuple<_Tp...> >::type&
1124get(tuple<_Tp...>& __t) _NOEXCEPT
1125{
1126    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1127    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1128}
1129
1130template <size_t _Ip, class ..._Tp>
1131inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1132const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1133get(const tuple<_Tp...>& __t) _NOEXCEPT
1134{
1135    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1136    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1137}
1138
1139template <size_t _Ip, class ..._Tp>
1140inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1141typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1142get(tuple<_Tp...>&& __t) _NOEXCEPT
1143{
1144    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1145    return static_cast<type&&>(
1146             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1147}
1148
1149template <size_t _Ip, class ..._Tp>
1150inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1151const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1152get(const tuple<_Tp...>&& __t) _NOEXCEPT
1153{
1154    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1155    return static_cast<const type&&>(
1156             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1157}
1158
1159#if _LIBCPP_STD_VER > 11
1160
1161namespace __find_detail {
1162
1163static constexpr size_t __not_found = -1;
1164static constexpr size_t __ambiguous = __not_found - 1;
1165
1166inline _LIBCPP_INLINE_VISIBILITY
1167constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
1168    return !__matches ? __res :
1169        (__res == __not_found ? __curr_i : __ambiguous);
1170}
1171
1172template <size_t _Nx>
1173inline _LIBCPP_INLINE_VISIBILITY
1174constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1175  return __i == _Nx ? __not_found :
1176      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
1177}
1178
1179template <class _T1, class ..._Args>
1180struct __find_exactly_one_checked {
1181    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1182    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1183    static_assert(value != __not_found, "type not found in type list" );
1184    static_assert(value != __ambiguous, "type occurs more than once in type list");
1185};
1186
1187template <class _T1>
1188struct __find_exactly_one_checked<_T1> {
1189    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1190};
1191
1192} // namespace __find_detail;
1193
1194template <typename _T1, typename... _Args>
1195struct __find_exactly_one_t
1196    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1197};
1198
1199template <class _T1, class... _Args>
1200inline _LIBCPP_INLINE_VISIBILITY
1201constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1202{
1203    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1204}
1205
1206template <class _T1, class... _Args>
1207inline _LIBCPP_INLINE_VISIBILITY
1208constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1209{
1210    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1211}
1212
1213template <class _T1, class... _Args>
1214inline _LIBCPP_INLINE_VISIBILITY
1215constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1216{
1217    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1218}
1219
1220template <class _T1, class... _Args>
1221inline _LIBCPP_INLINE_VISIBILITY
1222constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1223{
1224    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1225}
1226
1227#endif
1228
1229// tie
1230
1231template <class ..._Tp>
1232inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1233tuple<_Tp&...>
1234tie(_Tp&... __t) _NOEXCEPT
1235{
1236    return tuple<_Tp&...>(__t...);
1237}
1238
1239template <class _Up>
1240struct __ignore_t
1241{
1242    template <class _Tp>
1243    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1244    const __ignore_t& operator=(_Tp&&) const {return *this;}
1245};
1246
1247namespace {
1248  _LIBCPP_INLINE_VAR constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1249}
1250
1251template <class... _Tp>
1252inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1253tuple<typename __unwrap_ref_decay<_Tp>::type...>
1254make_tuple(_Tp&&... __t)
1255{
1256    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1257}
1258
1259template <class... _Tp>
1260inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1261tuple<_Tp&&...>
1262forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1263{
1264    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1265}
1266
1267template <size_t _Ip>
1268struct __tuple_equal
1269{
1270    template <class _Tp, class _Up>
1271    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1272    bool operator()(const _Tp& __x, const _Up& __y)
1273    {
1274        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1275    }
1276};
1277
1278template <>
1279struct __tuple_equal<0>
1280{
1281    template <class _Tp, class _Up>
1282    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1283    bool operator()(const _Tp&, const _Up&)
1284    {
1285        return true;
1286    }
1287};
1288
1289template <class ..._Tp, class ..._Up>
1290inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1291bool
1292operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1293{
1294    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1295    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1296}
1297
1298template <class ..._Tp, class ..._Up>
1299inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1300bool
1301operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1302{
1303    return !(__x == __y);
1304}
1305
1306template <size_t _Ip>
1307struct __tuple_less
1308{
1309    template <class _Tp, class _Up>
1310    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1311    bool operator()(const _Tp& __x, const _Up& __y)
1312    {
1313        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1314        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1315            return true;
1316        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1317            return false;
1318        return __tuple_less<_Ip-1>()(__x, __y);
1319    }
1320};
1321
1322template <>
1323struct __tuple_less<0>
1324{
1325    template <class _Tp, class _Up>
1326    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1327    bool operator()(const _Tp&, const _Up&)
1328    {
1329        return false;
1330    }
1331};
1332
1333template <class ..._Tp, class ..._Up>
1334inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1335bool
1336operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1337{
1338    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1339    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1340}
1341
1342template <class ..._Tp, class ..._Up>
1343inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1344bool
1345operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1346{
1347    return __y < __x;
1348}
1349
1350template <class ..._Tp, class ..._Up>
1351inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1352bool
1353operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1354{
1355    return !(__x < __y);
1356}
1357
1358template <class ..._Tp, class ..._Up>
1359inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1360bool
1361operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1362{
1363    return !(__y < __x);
1364}
1365
1366// tuple_cat
1367
1368template <class _Tp, class _Up> struct __tuple_cat_type;
1369
1370template <class ..._Ttypes, class ..._Utypes>
1371struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1372{
1373    typedef _LIBCPP_NODEBUG_TYPE tuple<_Ttypes..., _Utypes...> type;
1374};
1375
1376template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1377struct __tuple_cat_return_1
1378{
1379};
1380
1381template <class ..._Types, class _Tuple0>
1382struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1383{
1384    typedef _LIBCPP_NODEBUG_TYPE typename __tuple_cat_type<tuple<_Types...>,
1385            typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type>::type
1386                                                                           type;
1387};
1388
1389template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1390struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1391    : public __tuple_cat_return_1<
1392                 typename __tuple_cat_type<
1393                     tuple<_Types...>,
1394                     typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type
1395                 >::type,
1396                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
1397                 _Tuple1, _Tuples...>
1398{
1399};
1400
1401template <class ..._Tuples> struct __tuple_cat_return;
1402
1403template <class _Tuple0, class ..._Tuples>
1404struct __tuple_cat_return<_Tuple0, _Tuples...>
1405    : public __tuple_cat_return_1<tuple<>,
1406         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
1407                                                                     _Tuples...>
1408{
1409};
1410
1411template <>
1412struct __tuple_cat_return<>
1413{
1414    typedef _LIBCPP_NODEBUG_TYPE tuple<> type;
1415};
1416
1417inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1418tuple<>
1419tuple_cat()
1420{
1421    return tuple<>();
1422}
1423
1424template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1425struct __tuple_cat_return_ref_imp;
1426
1427template <class ..._Types, size_t ..._I0, class _Tuple0>
1428struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1429{
1430    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1431    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
1432                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
1433};
1434
1435template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1436struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1437                                  _Tuple0, _Tuple1, _Tuples...>
1438    : public __tuple_cat_return_ref_imp<
1439         tuple<_Types..., typename __apply_cv<_Tuple0,
1440               typename tuple_element<_I0,
1441                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
1442         typename __make_tuple_indices<tuple_size<typename
1443                                 remove_reference<_Tuple1>::type>::value>::type,
1444         _Tuple1, _Tuples...>
1445{
1446};
1447
1448template <class _Tuple0, class ..._Tuples>
1449struct __tuple_cat_return_ref
1450    : public __tuple_cat_return_ref_imp<tuple<>,
1451               typename __make_tuple_indices<
1452                        tuple_size<typename remove_reference<_Tuple0>::type>::value
1453               >::type, _Tuple0, _Tuples...>
1454{
1455};
1456
1457template <class _Types, class _I0, class _J0>
1458struct __tuple_cat;
1459
1460template <class ..._Types, size_t ..._I0, size_t ..._J0>
1461struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1462{
1463    template <class _Tuple0>
1464    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1465    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1466    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1467    {
1468        return _VSTD::forward_as_tuple(
1469            _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1470            _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1471    }
1472
1473    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1474    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1475    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1476    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1477    {
1478        typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1479        typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple1>::type _T1;
1480        return __tuple_cat<
1481            tuple<_Types...,
1482                  typename __apply_cv<_Tuple0, typename tuple_element<
1483                                                   _J0, _T0>::type>::type&&...>,
1484            typename __make_tuple_indices<sizeof...(_Types) +
1485                                          tuple_size<_T0>::value>::type,
1486            typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1487            _VSTD::forward_as_tuple(
1488                _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1489                _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...),
1490            _VSTD::forward<_Tuple1>(__t1), _VSTD::forward<_Tuples>(__tpls)...);
1491    }
1492};
1493
1494template <class _Tuple0, class... _Tuples>
1495inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1496typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1497tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1498{
1499    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1500    return __tuple_cat<tuple<>, __tuple_indices<>,
1501                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1502                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1503                                            _VSTD::forward<_Tuples>(__tpls)...);
1504}
1505
1506template <class ..._Tp, class _Alloc>
1507struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1508    : true_type {};
1509
1510template <class _T1, class _T2>
1511template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1512inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1513pair<_T1, _T2>::pair(piecewise_construct_t,
1514                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1515                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1516    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1517      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1518{
1519}
1520
1521#if _LIBCPP_STD_VER > 14
1522template <class _Tp>
1523_LIBCPP_INLINE_VAR constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1524
1525#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1526
1527template <class _Fn, class _Tuple, size_t ..._Id>
1528inline _LIBCPP_INLINE_VISIBILITY
1529constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1530                                            __tuple_indices<_Id...>)
1531_LIBCPP_NOEXCEPT_RETURN(
1532    _VSTD::__invoke_constexpr(
1533        _VSTD::forward<_Fn>(__f),
1534        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1535)
1536
1537template <class _Fn, class _Tuple>
1538inline _LIBCPP_INLINE_VISIBILITY
1539constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1540_LIBCPP_NOEXCEPT_RETURN(
1541    _VSTD::__apply_tuple_impl(
1542        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1543        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1544)
1545
1546template <class _Tp, class _Tuple, size_t... _Idx>
1547inline _LIBCPP_INLINE_VISIBILITY
1548constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1549_LIBCPP_NOEXCEPT_RETURN(
1550    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1551)
1552
1553template <class _Tp, class _Tuple>
1554inline _LIBCPP_INLINE_VISIBILITY
1555constexpr _Tp make_from_tuple(_Tuple&& __t)
1556_LIBCPP_NOEXCEPT_RETURN(
1557    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1558        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1559)
1560
1561#undef _LIBCPP_NOEXCEPT_RETURN
1562
1563#endif // _LIBCPP_STD_VER > 14
1564
1565#endif // !defined(_LIBCPP_CXX03_LANG)
1566
1567_LIBCPP_END_NAMESPACE_STD
1568
1569#endif // _LIBCPP_TUPLE
1570