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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
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
29    template<class... UTypes>
30        constexpr explicit(see-below) tuple(tuple<UTypes...>&);  // C++23
31    template <class... U>
32        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
33    template <class... U>
34        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
35    template<class... UTypes>
36        constexpr explicit(see-below) tuple(const tuple<UTypes...>&&); // C++23
37
38    template<class U1, class U2>
39        constexpr explicit(see-below) tuple(pair<U1, U2>&);  // iff sizeof...(Types) == 2 // C++23
40    template <class U1, class U2>
41        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
42    template <class U1, class U2>
43        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
44    template<class U1, class U2>
45        constexpr explicit(see-below) tuple(const pair<U1, U2>&&);  // iff sizeof...(Types) == 2 // C++23
46
47    // allocator-extended constructors
48    template <class Alloc>
49        tuple(allocator_arg_t, const Alloc& a);
50    template <class Alloc>
51        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
52    template <class Alloc, class... U>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
54    template <class Alloc>
55        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
56    template <class Alloc>
57        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
58    template<class Alloc, class... UTypes>
59        constexpr explicit(see-below)
60          tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&);                      // C++23
61    template <class Alloc, class... U>
62        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
63    template <class Alloc, class... U>
64        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
65    template<class Alloc, class... UTypes>
66        constexpr explicit(see-below)
67          tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&&);               // C++23
68    template<class Alloc, class U1, class U2>
69        constexpr explicit(see-below)
70          tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&);                          // C++23
71    template <class Alloc, class U1, class U2>
72        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
73    template <class Alloc, class U1, class U2>
74        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
75    template<class Alloc, class U1, class U2>
76        constexpr explicit(see-below)
77          tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&&);                   // C++23
78
79    tuple& operator=(const tuple&);                                                       // constexpr in C++20
80    constexpr const tuple& operator=(const tuple&) const;                                 // C++23
81    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
82    constexpr const tuple& operator=(tuple&&) const;                                      // C++23
83    template <class... U>
84        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
85    template<class... UTypes>
86        constexpr const tuple& operator=(const tuple<UTypes...>&) const;                  // C++23
87    template <class... U>
88        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
89    template<class... UTypes>
90        constexpr const tuple& operator=(tuple<UTypes...>&&) const;                       // C++23
91    template <class U1, class U2>
92        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
93    template<class U1, class U2>
94        constexpr const tuple& operator=(const pair<U1, U2>&) const;   // iff sizeof...(Types) == 2 // C++23
95    template <class U1, class U2>
96        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
97    template<class U1, class U2>
98        constexpr const tuple& operator=(pair<U1, U2>&&) const;  // iff sizeof...(Types) == 2 // C++23
99
100    template<class U, size_t N>
101        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
102    template<class U, size_t N>
103        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
104
105    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
106    constexpr void swap(const tuple&) const noexcept(see-below);                          // C++23
107};
108
109
110template<class... TTypes, class... UTypes, template<class> class TQual, template<class> class UQual> // since C++23
111  requires requires { typename tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>; }
112struct basic_common_reference<tuple<TTypes...>, tuple<UTypes...>, TQual, UQual> {
113  using type = tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>;
114};
115
116template<class... TTypes, class... UTypes>                                // since C++23
117  requires requires { typename tuple<common_type_t<TTypes, UTypes>...>; }
118struct common_type<tuple<TTypes...>, tuple<UTypes...>> {
119  using type = tuple<common_type_t<TTypes, UTypes>...>;
120};
121
122template <class ...T>
123tuple(T...) -> tuple<T...>;                                         // since C++17
124template <class T1, class T2>
125tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
126template <class Alloc, class ...T>
127tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
128template <class Alloc, class T1, class T2>
129tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
130template <class Alloc, class ...T>
131tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
132
133inline constexpr unspecified ignore;
134
135template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
136template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
137template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
138template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
139
140// [tuple.apply], calling a function with a tuple of arguments:
141template <class F, class Tuple>
142  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
143template <class T, class Tuple>
144  constexpr T make_from_tuple(Tuple&& t); // C++17
145
146// 20.4.1.4, tuple helper classes:
147template <class T> struct tuple_size; // undefined
148template <class... T> struct tuple_size<tuple<T...>>;
149template <class T>
150 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
151template <size_t I, class T> struct tuple_element; // undefined
152template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
153template <size_t I, class T>
154  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
155
156// 20.4.1.5, element access:
157template <size_t I, class... T>
158    typename tuple_element<I, tuple<T...>>::type&
159    get(tuple<T...>&) noexcept; // constexpr in C++14
160template <size_t I, class... T>
161    const typename tuple_element<I, tuple<T...>>::type&
162    get(const tuple<T...>&) noexcept; // constexpr in C++14
163template <size_t I, class... T>
164    typename tuple_element<I, tuple<T...>>::type&&
165    get(tuple<T...>&&) noexcept; // constexpr in C++14
166template <size_t I, class... T>
167    const typename tuple_element<I, tuple<T...>>::type&&
168    get(const tuple<T...>&&) noexcept; // constexpr in C++14
169
170template <class T1, class... T>
171    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
172template <class T1, class... T>
173    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
174template <class T1, class... T>
175    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
176template <class T1, class... T>
177    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
178
179// 20.4.1.6, relational operators:
180template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
181template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
182template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
183template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
184template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
185template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
186template<class... T, class... U>
187  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
188    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
189
190template <class... Types, class Alloc>
191  struct uses_allocator<tuple<Types...>, Alloc>;
192
193template <class... Types>
194  void
195  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
196
197template <class... Types>
198  constexpr void swap(const tuple<Types...>& x, const tuple<Types...>& y) noexcept(see-below);   // C++23
199
200}  // std
201
202*/
203
204#include <__assert> // all public C++ headers provide the assertion handler
205#include <__compare/common_comparison_category.h>
206#include <__compare/synth_three_way.h>
207#include <__config>
208#include <__functional/invoke.h>
209#include <__fwd/array.h>
210#include <__fwd/get.h>
211#include <__fwd/tuple.h>
212#include <__memory/allocator_arg_t.h>
213#include <__memory/uses_allocator.h>
214#include <__tuple/make_tuple_types.h>
215#include <__tuple/sfinae_helpers.h>
216#include <__tuple/tuple_element.h>
217#include <__tuple/tuple_indices.h>
218#include <__tuple/tuple_like_ext.h>
219#include <__tuple/tuple_size.h>
220#include <__tuple/tuple_types.h>
221#include <__type_traits/apply_cv.h>
222#include <__type_traits/common_reference.h>
223#include <__type_traits/common_type.h>
224#include <__type_traits/conditional.h>
225#include <__type_traits/conjunction.h>
226#include <__type_traits/copy_cvref.h>
227#include <__type_traits/disjunction.h>
228#include <__type_traits/is_arithmetic.h>
229#include <__type_traits/is_assignable.h>
230#include <__type_traits/is_constructible.h>
231#include <__type_traits/is_convertible.h>
232#include <__type_traits/is_copy_assignable.h>
233#include <__type_traits/is_copy_constructible.h>
234#include <__type_traits/is_default_constructible.h>
235#include <__type_traits/is_empty.h>
236#include <__type_traits/is_final.h>
237#include <__type_traits/is_implicitly_default_constructible.h>
238#include <__type_traits/is_move_assignable.h>
239#include <__type_traits/is_move_constructible.h>
240#include <__type_traits/is_nothrow_assignable.h>
241#include <__type_traits/is_nothrow_constructible.h>
242#include <__type_traits/is_nothrow_copy_assignable.h>
243#include <__type_traits/is_nothrow_copy_constructible.h>
244#include <__type_traits/is_nothrow_default_constructible.h>
245#include <__type_traits/is_nothrow_move_assignable.h>
246#include <__type_traits/is_reference.h>
247#include <__type_traits/is_same.h>
248#include <__type_traits/is_swappable.h>
249#include <__type_traits/lazy.h>
250#include <__type_traits/maybe_const.h>
251#include <__type_traits/nat.h>
252#include <__type_traits/negation.h>
253#include <__type_traits/remove_cvref.h>
254#include <__type_traits/remove_reference.h>
255#include <__type_traits/unwrap_ref.h>
256#include <__utility/forward.h>
257#include <__utility/integer_sequence.h>
258#include <__utility/move.h>
259#include <__utility/pair.h>
260#include <__utility/piecewise_construct.h>
261#include <__utility/swap.h>
262#include <cstddef>
263#include <version>
264
265// standard-mandated includes
266
267// [tuple.syn]
268#include <compare>
269
270#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
271#  pragma GCC system_header
272#endif
273
274_LIBCPP_PUSH_MACROS
275#include <__undef_macros>
276
277_LIBCPP_BEGIN_NAMESPACE_STD
278
279#ifndef _LIBCPP_CXX03_LANG
280
281
282// __tuple_leaf
283
284template <size_t _Ip, class _Hp,
285          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
286         >
287class __tuple_leaf;
288
289template <size_t _Ip, class _Hp, bool _Ep>
290inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
291void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
292    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
293{
294    swap(__x.get(), __y.get());
295}
296
297template <size_t _Ip, class _Hp, bool _Ep>
298_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
299void swap(const __tuple_leaf<_Ip, _Hp, _Ep>& __x, const __tuple_leaf<_Ip, _Hp, _Ep>& __y)
300     _NOEXCEPT_(__is_nothrow_swappable<const _Hp>::value) {
301  swap(__x.get(), __y.get());
302}
303
304template <size_t _Ip, class _Hp, bool>
305class __tuple_leaf
306{
307    _Hp __value_;
308
309    template <class _Tp>
310    static _LIBCPP_HIDE_FROM_ABI constexpr bool __can_bind_reference() {
311#if __has_keyword(__reference_binds_to_temporary)
312      return !__reference_binds_to_temporary(_Hp, _Tp);
313#else
314      return true;
315#endif
316    }
317
318    _LIBCPP_CONSTEXPR_SINCE_CXX14
319    __tuple_leaf& operator=(const __tuple_leaf&);
320public:
321    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
322             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
323       {static_assert(!is_reference<_Hp>::value,
324              "Attempted to default construct a reference element in a tuple");}
325
326    template <class _Alloc>
327        _LIBCPP_INLINE_VISIBILITY constexpr
328        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
329            : __value_()
330        {static_assert(!is_reference<_Hp>::value,
331              "Attempted to default construct a reference element in a tuple");}
332
333    template <class _Alloc>
334        _LIBCPP_INLINE_VISIBILITY constexpr
335        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
336            : __value_(allocator_arg_t(), __a)
337        {static_assert(!is_reference<_Hp>::value,
338              "Attempted to default construct a reference element in a tuple");}
339
340    template <class _Alloc>
341        _LIBCPP_INLINE_VISIBILITY constexpr
342        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
343            : __value_(__a)
344        {static_assert(!is_reference<_Hp>::value,
345              "Attempted to default construct a reference element in a tuple");}
346
347    template <class _Tp,
348              class = __enable_if_t<
349                  _And<
350                      _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>,
351                      is_constructible<_Hp, _Tp>
352                    >::value
353                >
354            >
355        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
356        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
357            : __value_(_VSTD::forward<_Tp>(__t))
358        {static_assert(__can_bind_reference<_Tp&&>(),
359       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
360
361    template <class _Tp, class _Alloc>
362        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
363        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
364            : __value_(_VSTD::forward<_Tp>(__t))
365        {static_assert(__can_bind_reference<_Tp&&>(),
366       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
367
368    template <class _Tp, class _Alloc>
369        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
370        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
371            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
372        {static_assert(!is_reference<_Hp>::value,
373            "Attempted to uses-allocator construct a reference element in a tuple");}
374
375    template <class _Tp, class _Alloc>
376        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
377        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
378            : __value_(_VSTD::forward<_Tp>(__t), __a)
379        {static_assert(!is_reference<_Hp>::value,
380           "Attempted to uses-allocator construct a reference element in a tuple");}
381
382    _LIBCPP_HIDE_FROM_ABI __tuple_leaf(const __tuple_leaf& __t) = default;
383    _LIBCPP_HIDE_FROM_ABI __tuple_leaf(__tuple_leaf&& __t) = default;
384
385    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
386    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
387    {
388        _VSTD::swap(*this, __t);
389        return 0;
390    }
391
392    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
393    int swap(const __tuple_leaf& __t) const _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
394        _VSTD::swap(*this, __t);
395        return 0;
396    }
397
398    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14       _Hp& get()       _NOEXCEPT {return __value_;}
399    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT {return __value_;}
400};
401
402template <size_t _Ip, class _Hp>
403class __tuple_leaf<_Ip, _Hp, true>
404    : private _Hp
405{
406    _LIBCPP_CONSTEXPR_SINCE_CXX14
407    __tuple_leaf& operator=(const __tuple_leaf&);
408public:
409    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
410             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
411
412    template <class _Alloc>
413        _LIBCPP_INLINE_VISIBILITY constexpr
414        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
415
416    template <class _Alloc>
417        _LIBCPP_INLINE_VISIBILITY constexpr
418        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
419            : _Hp(allocator_arg_t(), __a) {}
420
421    template <class _Alloc>
422        _LIBCPP_INLINE_VISIBILITY constexpr
423        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
424            : _Hp(__a) {}
425
426    template <class _Tp,
427              class = __enable_if_t<
428                  _And<
429                    _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>,
430                    is_constructible<_Hp, _Tp>
431                  >::value
432                >
433            >
434        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
435        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
436            : _Hp(_VSTD::forward<_Tp>(__t)) {}
437
438    template <class _Tp, class _Alloc>
439        _LIBCPP_INLINE_VISIBILITY constexpr
440        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
441            : _Hp(_VSTD::forward<_Tp>(__t)) {}
442
443    template <class _Tp, class _Alloc>
444        _LIBCPP_INLINE_VISIBILITY constexpr
445        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
446            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
447
448    template <class _Tp, class _Alloc>
449        _LIBCPP_INLINE_VISIBILITY constexpr
450        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
451            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
452
453    __tuple_leaf(__tuple_leaf const &) = default;
454    __tuple_leaf(__tuple_leaf &&) = default;
455
456    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
457    int
458    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
459    {
460        _VSTD::swap(*this, __t);
461        return 0;
462    }
463
464    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
465    int swap(const __tuple_leaf& __rhs) const _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
466        _VSTD::swap(*this, __rhs);
467        return 0;
468    }
469
470    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
471    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
472};
473
474template <class ..._Tp>
475_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
476void __swallow(_Tp&&...) _NOEXCEPT {}
477
478template <class _Tp>
479struct __all_default_constructible;
480
481template <class ..._Tp>
482struct __all_default_constructible<__tuple_types<_Tp...>>
483    : __all<is_default_constructible<_Tp>::value...>
484{ };
485
486// __tuple_impl
487
488template<class _Indx, class ..._Tp> struct __tuple_impl;
489
490template<size_t ..._Indx, class ..._Tp>
491struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
492    : public __tuple_leaf<_Indx, _Tp>...
493{
494    _LIBCPP_INLINE_VISIBILITY
495    constexpr __tuple_impl()
496        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
497
498    template <size_t ..._Uf, class ..._Tf,
499              size_t ..._Ul, class ..._Tl, class ..._Up>
500        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
501        explicit
502        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
503                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
504                     _Up&&... __u)
505                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
506                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
507            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
508            __tuple_leaf<_Ul, _Tl>()...
509            {}
510
511    template <class _Alloc, size_t ..._Uf, class ..._Tf,
512              size_t ..._Ul, class ..._Tl, class ..._Up>
513        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
514        explicit
515        __tuple_impl(allocator_arg_t, const _Alloc& __a,
516                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
517                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
518                     _Up&&... __u) :
519            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
520            _VSTD::forward<_Up>(__u))...,
521            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
522            {}
523
524    template <class _Tuple,
525              class = __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value>
526             >
527        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
528        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
529                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
530            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
531                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
532            {}
533
534    template <class _Alloc, class _Tuple,
535              class = __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value>
536             >
537        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
538        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
539            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
540                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
541                                       _VSTD::forward<typename tuple_element<_Indx,
542                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
543            {}
544
545    __tuple_impl(const __tuple_impl&) = default;
546    __tuple_impl(__tuple_impl&&) = default;
547
548    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
549    void swap(__tuple_impl& __t)
550        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
551    {
552        _VSTD::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
553    }
554
555    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
556    void swap(const __tuple_impl& __t) const
557        _NOEXCEPT_(__all<__is_nothrow_swappable<const _Tp>::value...>::value)
558    {
559        _VSTD::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t))...);
560    }
561};
562
563template<class _Dest, class _Source, size_t ..._Np>
564_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
565void __memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
566    _VSTD::__swallow(((_VSTD::get<_Np>(__dest) = _VSTD::get<_Np>(__source)), void(), 0)...);
567}
568
569template<class _Dest, class _Source, class ..._Up, size_t ..._Np>
570_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
571void __memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
572    _VSTD::__swallow(((
573        _VSTD::get<_Np>(__dest) = _VSTD::forward<_Up>(_VSTD::get<_Np>(__source))
574    ), void(), 0)...);
575}
576
577template <class ..._Tp>
578class _LIBCPP_TEMPLATE_VIS tuple
579{
580    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
581
582    _BaseT __base_;
583
584    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_SINCE_CXX14
585        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
586    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_SINCE_CXX14
587        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
588    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_SINCE_CXX14
589        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
590    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_SINCE_CXX14
591        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
592public:
593    // [tuple.cnstr]
594
595_LIBCPP_DIAGNOSTIC_PUSH
596_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions")
597_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions")
598
599    // tuple() constructors (including allocator_arg_t variants)
600    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
601              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
602        _And<
603            _IsDefault<_Tp>...
604        >::value
605    , int> = 0>
606    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
607    explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value) tuple()
608        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
609    { }
610
611    template <class _Alloc,
612              template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
613              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
614        _And<
615            _IsDefault<_Tp>...
616        >::value
617    , int> = 0>
618    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
619    explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value) tuple(allocator_arg_t, _Alloc const& __a)
620      : __base_(allocator_arg_t(), __a,
621                    __tuple_indices<>(), __tuple_types<>(),
622                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
623                    __tuple_types<_Tp...>()) {}
624
625    // tuple(const T&...) constructors (including allocator_arg_t variants)
626    template <template<class...> class _And = _And, __enable_if_t<
627        _And<
628            _BoolConstant<sizeof...(_Tp) >= 1>,
629            is_copy_constructible<_Tp>...
630        >::value
631    , int> = 0>
632    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
633    explicit(_Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value) tuple(const _Tp& ... __t)
634        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
635        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
636                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
637                typename __make_tuple_indices<0>::type(),
638                typename __make_tuple_types<tuple, 0>::type(),
639                __t...
640               ) {}
641
642    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
643        _And<
644            _BoolConstant<sizeof...(_Tp) >= 1>,
645            is_copy_constructible<_Tp>...
646        >::value
647    , int> = 0>
648    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
649    explicit(_Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value) tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
650        : __base_(allocator_arg_t(), __a,
651                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
652                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
653                typename __make_tuple_indices<0>::type(),
654                typename __make_tuple_types<tuple, 0>::type(),
655                __t...
656               ) {}
657
658    // tuple(U&& ...) constructors (including allocator_arg_t variants)
659    template <class ..._Up> struct _IsThisTuple : false_type { };
660    template <class _Up> struct _IsThisTuple<_Up> : is_same<__remove_cvref_t<_Up>, tuple> { };
661
662    template <class ..._Up>
663    struct _EnableUTypesCtor : _And<
664        _BoolConstant<sizeof...(_Tp) >= 1>,
665        _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
666        is_constructible<_Tp, _Up>...
667    > { };
668
669    template <class ..._Up, __enable_if_t<
670        _And<
671            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
672            _EnableUTypesCtor<_Up...>
673        >::value
674    , int> = 0>
675    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
676    explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value) tuple(_Up&&... __u)
677        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
678        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
679                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
680                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
681                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
682                    _VSTD::forward<_Up>(__u)...) {}
683
684    template <class _Alloc, class ..._Up, __enable_if_t<
685        _And<
686            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
687            _EnableUTypesCtor<_Up...>
688        >::value
689    , int> = 0>
690    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
691    explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value) tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
692        : __base_(allocator_arg_t(), __a,
693                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
694                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
695                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
696                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
697                    _VSTD::forward<_Up>(__u)...) {}
698
699    // Copy and move constructors (including the allocator_arg_t variants)
700    tuple(const tuple&) = default;
701    tuple(tuple&&) = default;
702
703    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
704        _And<is_copy_constructible<_Tp>...>::value
705    , int> = 0>
706    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
707    tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
708        : __base_(allocator_arg_t(), __alloc, __t)
709    { }
710
711    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
712        _And<is_move_constructible<_Tp>...>::value
713    , int> = 0>
714    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
715    tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
716        : __base_(allocator_arg_t(), __alloc, _VSTD::move(__t))
717    { }
718
719    // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
720
721    template <class _OtherTuple, class _DecayedOtherTuple = __remove_cvref_t<_OtherTuple>, class = void>
722    struct _EnableCtorFromUTypesTuple : false_type {};
723
724    template <class _OtherTuple, class... _Up>
725    struct _EnableCtorFromUTypesTuple<_OtherTuple, tuple<_Up...>,
726              // the length of the packs needs to checked first otherwise the 2 packs cannot be expanded simultaneously below
727               __enable_if_t<sizeof...(_Up) == sizeof...(_Tp)>> : _And<
728        // the two conditions below are not in spec. The purpose is to disable the UTypes Ctor when copy/move Ctor can work.
729        // Otherwise, is_constructible can trigger hard error in those cases https://godbolt.org/z/M94cGdKcE
730        _Not<is_same<_OtherTuple, const tuple&> >,
731        _Not<is_same<_OtherTuple, tuple&&> >,
732        is_constructible<_Tp, __copy_cvref_t<_OtherTuple, _Up> >...,
733        _Lazy<_Or, _BoolConstant<sizeof...(_Tp) != 1>,
734            // _Tp and _Up are 1-element packs - the pack expansions look
735            // weird to avoid tripping up the type traits in degenerate cases
736            _Lazy<_And,
737                _Not<is_same<_Tp, _Up> >...,
738                _Not<is_convertible<_OtherTuple, _Tp> >...,
739                _Not<is_constructible<_Tp, _OtherTuple> >...
740            >
741        >
742    > {};
743
744    template <class ..._Up, __enable_if_t<
745        _And<
746            _EnableCtorFromUTypesTuple<const tuple<_Up...>&>
747        >::value
748    , int> = 0>
749    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
750    explicit(_Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value) tuple(const tuple<_Up...>& __t)
751        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
752        : __base_(__t)
753    { }
754
755    template <class ..._Up, class _Alloc, __enable_if_t<
756        _And<
757            _EnableCtorFromUTypesTuple<const tuple<_Up...>&>
758        >::value
759    , int> = 0>
760    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
761    explicit(_Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value) tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
762        : __base_(allocator_arg_t(), __a, __t)
763    { }
764
765#if _LIBCPP_STD_VER >= 23
766    // tuple(tuple<U...>&) constructors (including allocator_arg_t variants)
767
768    template <class... _Up, enable_if_t<
769        _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
770    _LIBCPP_HIDE_FROM_ABI constexpr
771        explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value)
772    tuple(tuple<_Up...>& __t) : __base_(__t) {}
773
774    template <class _Alloc, class... _Up, enable_if_t<
775        _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
776    _LIBCPP_HIDE_FROM_ABI constexpr
777        explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value)
778    tuple(allocator_arg_t, const _Alloc& __alloc, tuple<_Up...>& __t) : __base_(allocator_arg_t(), __alloc, __t) {}
779#endif // _LIBCPP_STD_VER >= 23
780
781    // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
782    template <class ..._Up, __enable_if_t<
783        _And<
784            _EnableCtorFromUTypesTuple<tuple<_Up...>&&>
785        >::value
786    , int> = 0>
787    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
788    explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value) tuple(tuple<_Up...>&& __t)
789        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
790        : __base_(_VSTD::move(__t))
791    { }
792
793    template <class _Alloc, class ..._Up, __enable_if_t<
794        _And<
795            _EnableCtorFromUTypesTuple<tuple<_Up...>&&>
796        >::value
797    , int> = 0>
798    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
799    explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value) tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
800        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
801    { }
802
803#if _LIBCPP_STD_VER >= 23
804    // tuple(const tuple<U...>&&) constructors (including allocator_arg_t variants)
805
806    template <class... _Up, enable_if_t<
807        _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
808    _LIBCPP_HIDE_FROM_ABI constexpr
809        explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
810    tuple(const tuple<_Up...>&& __t) : __base_(std::move(__t)) {}
811
812    template <class _Alloc, class... _Up, enable_if_t<
813        _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
814    _LIBCPP_HIDE_FROM_ABI constexpr
815        explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
816    tuple(allocator_arg_t, const _Alloc& __alloc, const tuple<_Up...>&& __t)
817        : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
818#endif // _LIBCPP_STD_VER >= 23
819
820    // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
821
822    template <template <class...> class _Pred, class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
823    struct _CtorPredicateFromPair : false_type{};
824
825    template <template <class...> class _Pred, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
826    struct _CtorPredicateFromPair<_Pred, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> > : _And<
827        _Pred<_Tp1, __copy_cvref_t<_Pair, _Up1> >,
828        _Pred<_Tp2, __copy_cvref_t<_Pair, _Up2> >
829    > {};
830
831    template <class _Pair>
832    struct _EnableCtorFromPair : _CtorPredicateFromPair<is_constructible, _Pair>{};
833
834    template <class _Pair>
835    struct _NothrowConstructibleFromPair : _CtorPredicateFromPair<is_nothrow_constructible, _Pair>{};
836
837    template <class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
838    struct _BothImplicitlyConvertible : false_type{};
839
840    template <class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
841    struct _BothImplicitlyConvertible<_Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> > : _And<
842        is_convertible<__copy_cvref_t<_Pair, _Up1>, _Tp1>,
843        is_convertible<__copy_cvref_t<_Pair, _Up2>, _Tp2>
844    > {};
845
846    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
847        _And<
848            _EnableCtorFromPair<const pair<_Up1, _Up2>&>
849        >::value
850    , int> = 0>
851    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
852    explicit(_Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value) tuple(const pair<_Up1, _Up2>& __p)
853        _NOEXCEPT_((_NothrowConstructibleFromPair<const pair<_Up1, _Up2>&>::value))
854        : __base_(__p)
855    { }
856
857    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
858        _And<
859            _EnableCtorFromPair<const pair<_Up1, _Up2>&>
860        >::value
861    , int> = 0>
862    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
863    explicit(_Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value) tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
864        : __base_(allocator_arg_t(), __a, __p)
865    { }
866
867#if _LIBCPP_STD_VER >= 23
868    // tuple(pair<U1, U2>&) constructors (including allocator_arg_t variants)
869
870    template <class _U1, class _U2, enable_if_t<
871        _EnableCtorFromPair<pair<_U1, _U2>&>::value>* = nullptr>
872    _LIBCPP_HIDE_FROM_ABI constexpr
873        explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
874    tuple(pair<_U1, _U2>& __p) : __base_(__p) {}
875
876    template <class _Alloc, class _U1, class _U2, enable_if_t<
877        _EnableCtorFromPair<std::pair<_U1, _U2>&>::value>* = nullptr>
878    _LIBCPP_HIDE_FROM_ABI constexpr
879        explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
880    tuple(allocator_arg_t, const _Alloc& __alloc, pair<_U1, _U2>& __p) : __base_(allocator_arg_t(), __alloc, __p) {}
881#endif
882
883    // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
884
885    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
886        _And<
887            _EnableCtorFromPair<pair<_Up1, _Up2>&&>
888        >::value
889    , int> = 0>
890    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
891    explicit(_Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value) tuple(pair<_Up1, _Up2>&& __p)
892        _NOEXCEPT_((_NothrowConstructibleFromPair<pair<_Up1, _Up2>&&>::value))
893        : __base_(_VSTD::move(__p))
894    { }
895
896    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
897        _And<
898            _EnableCtorFromPair<pair<_Up1, _Up2>&&>
899        >::value
900    , int> = 0>
901    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
902    explicit(_Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value) tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
903        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
904    { }
905
906#if _LIBCPP_STD_VER >= 23
907    // tuple(const pair<U1, U2>&&) constructors (including allocator_arg_t variants)
908
909    template <class _U1, class _U2, enable_if_t<
910        _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
911    _LIBCPP_HIDE_FROM_ABI constexpr
912        explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
913    tuple(const pair<_U1, _U2>&& __p) : __base_(std::move(__p)) {}
914
915    template <class _Alloc, class _U1, class _U2, enable_if_t<
916        _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
917    _LIBCPP_HIDE_FROM_ABI constexpr
918        explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
919    tuple(allocator_arg_t, const _Alloc& __alloc, const pair<_U1, _U2>&& __p)
920        : __base_(allocator_arg_t(), __alloc, std::move(__p)) {}
921#endif // _LIBCPP_STD_VER >= 23
922
923_LIBCPP_DIAGNOSTIC_POP
924
925    // [tuple.assign]
926    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
927    tuple& operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
928        _NOEXCEPT_((_And<is_nothrow_copy_assignable<_Tp>...>::value))
929    {
930        _VSTD::__memberwise_copy_assign(*this, __tuple,
931            typename __make_tuple_indices<sizeof...(_Tp)>::type());
932        return *this;
933    }
934
935#if _LIBCPP_STD_VER >= 23
936    _LIBCPP_HIDE_FROM_ABI constexpr
937    const tuple& operator=(tuple const& __tuple) const
938      requires (_And<is_copy_assignable<const _Tp>...>::value) {
939        std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
940        return *this;
941    }
942
943    _LIBCPP_HIDE_FROM_ABI constexpr
944    const tuple& operator=(tuple&& __tuple) const
945      requires (_And<is_assignable<const _Tp&, _Tp>...>::value) {
946        std::__memberwise_forward_assign(*this,
947                                         std::move(__tuple),
948                                         __tuple_types<_Tp...>(),
949                                         typename __make_tuple_indices<sizeof...(_Tp)>::type());
950        return *this;
951    }
952#endif // _LIBCPP_STD_VER >= 23
953
954    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
955    tuple& operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
956        _NOEXCEPT_((_And<is_nothrow_move_assignable<_Tp>...>::value))
957    {
958        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
959            __tuple_types<_Tp...>(),
960            typename __make_tuple_indices<sizeof...(_Tp)>::type());
961        return *this;
962    }
963
964    template<class... _Up, __enable_if_t<
965        _And<
966            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
967            is_assignable<_Tp&, _Up const&>...
968        >::value
969    ,int> = 0>
970    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
971    tuple& operator=(tuple<_Up...> const& __tuple)
972        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
973    {
974        _VSTD::__memberwise_copy_assign(*this, __tuple,
975            typename __make_tuple_indices<sizeof...(_Tp)>::type());
976        return *this;
977    }
978
979    template<class... _Up, __enable_if_t<
980        _And<
981            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
982            is_assignable<_Tp&, _Up>...
983        >::value
984    ,int> = 0>
985    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
986    tuple& operator=(tuple<_Up...>&& __tuple)
987        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
988    {
989        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
990            __tuple_types<_Up...>(),
991            typename __make_tuple_indices<sizeof...(_Tp)>::type());
992        return *this;
993    }
994
995
996#if _LIBCPP_STD_VER >= 23
997    template <class... _UTypes, enable_if_t<
998        _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
999             is_assignable<const _Tp&, const _UTypes&>...>::value>* = nullptr>
1000    _LIBCPP_HIDE_FROM_ABI constexpr
1001    const tuple& operator=(const tuple<_UTypes...>& __u) const {
1002        std::__memberwise_copy_assign(*this,
1003                                      __u,
1004                                      typename __make_tuple_indices<sizeof...(_Tp)>::type());
1005        return *this;
1006    }
1007
1008    template <class... _UTypes, enable_if_t<
1009        _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
1010             is_assignable<const _Tp&, _UTypes>...>::value>* = nullptr>
1011    _LIBCPP_HIDE_FROM_ABI constexpr
1012    const tuple& operator=(tuple<_UTypes...>&& __u) const {
1013        std::__memberwise_forward_assign(*this,
1014                                         __u,
1015                                         __tuple_types<_UTypes...>(),
1016                                         typename __make_tuple_indices<sizeof...(_Tp)>::type());
1017        return *this;
1018    }
1019#endif // _LIBCPP_STD_VER >= 23
1020
1021    template <template<class...> class _Pred, bool _Const,
1022              class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
1023    struct _AssignPredicateFromPair : false_type {};
1024
1025    template <template<class...> class _Pred, bool _Const,
1026              class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
1027    struct _AssignPredicateFromPair<_Pred, _Const, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> > :
1028        _And<_Pred<__maybe_const<_Const, _Tp1>&, __copy_cvref_t<_Pair, _Up1> >,
1029             _Pred<__maybe_const<_Const, _Tp2>&, __copy_cvref_t<_Pair, _Up2> >
1030            > {};
1031
1032    template <bool _Const, class _Pair>
1033    struct _EnableAssignFromPair : _AssignPredicateFromPair<is_assignable, _Const, _Pair> {};
1034
1035    template <bool _Const, class _Pair>
1036    struct _NothrowAssignFromPair : _AssignPredicateFromPair<is_nothrow_assignable, _Const, _Pair> {};
1037
1038#if _LIBCPP_STD_VER >= 23
1039    template <class _U1, class _U2, enable_if_t<
1040        _EnableAssignFromPair<true, const pair<_U1, _U2>&>::value>* = nullptr>
1041    _LIBCPP_HIDE_FROM_ABI constexpr
1042    const tuple& operator=(const pair<_U1, _U2>& __pair) const
1043      noexcept(_NothrowAssignFromPair<true, const pair<_U1, _U2>&>::value) {
1044        std::get<0>(*this) = __pair.first;
1045        std::get<1>(*this) = __pair.second;
1046        return *this;
1047    }
1048
1049    template <class _U1, class _U2, enable_if_t<
1050        _EnableAssignFromPair<true, pair<_U1, _U2>&&>::value>* = nullptr>
1051    _LIBCPP_HIDE_FROM_ABI constexpr
1052    const tuple& operator=(pair<_U1, _U2>&& __pair) const
1053      noexcept(_NothrowAssignFromPair<true, pair<_U1, _U2>&&>::value) {
1054        std::get<0>(*this) = std::move(__pair.first);
1055        std::get<1>(*this) = std::move(__pair.second);
1056        return *this;
1057    }
1058#endif // _LIBCPP_STD_VER >= 23
1059
1060    template<class _Up1, class _Up2, __enable_if_t<
1061        _EnableAssignFromPair<false, pair<_Up1, _Up2> const&>::value
1062    ,int> = 0>
1063    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1064    tuple& operator=(pair<_Up1, _Up2> const& __pair)
1065        _NOEXCEPT_((_NothrowAssignFromPair<false, pair<_Up1, _Up2> const&>::value))
1066    {
1067        _VSTD::get<0>(*this) = __pair.first;
1068        _VSTD::get<1>(*this) = __pair.second;
1069        return *this;
1070    }
1071
1072    template<class _Up1, class _Up2, __enable_if_t<
1073        _EnableAssignFromPair<false, pair<_Up1, _Up2>&&>::value
1074    ,int> = 0>
1075    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1076    tuple& operator=(pair<_Up1, _Up2>&& __pair)
1077        _NOEXCEPT_((_NothrowAssignFromPair<false, pair<_Up1, _Up2>&&>::value))
1078    {
1079        _VSTD::get<0>(*this) = _VSTD::forward<_Up1>(__pair.first);
1080        _VSTD::get<1>(*this) = _VSTD::forward<_Up2>(__pair.second);
1081        return *this;
1082    }
1083
1084    // EXTENSION
1085    template<class _Up, size_t _Np, class = __enable_if_t<
1086        _And<
1087            _BoolConstant<_Np == sizeof...(_Tp)>,
1088            is_assignable<_Tp&, _Up const&>...
1089        >::value
1090    > >
1091    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1092    tuple& operator=(array<_Up, _Np> const& __array)
1093        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
1094    {
1095        _VSTD::__memberwise_copy_assign(*this, __array,
1096            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1097        return *this;
1098    }
1099
1100    // EXTENSION
1101    template<class _Up, size_t _Np, class = void, class = __enable_if_t<
1102        _And<
1103            _BoolConstant<_Np == sizeof...(_Tp)>,
1104            is_assignable<_Tp&, _Up>...
1105        >::value
1106    > >
1107    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1108    tuple& operator=(array<_Up, _Np>&& __array)
1109        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
1110    {
1111        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__array),
1112            __tuple_types<_If<true, _Up, _Tp>...>(),
1113            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1114        return *this;
1115    }
1116
1117    // [tuple.swap]
1118    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1119    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1120        {__base_.swap(__t.__base_);}
1121
1122#if _LIBCPP_STD_VER >= 23
1123    _LIBCPP_HIDE_FROM_ABI constexpr
1124    void swap(const tuple& __t) const noexcept(__all<is_nothrow_swappable_v<const _Tp&>...>::value) {
1125        __base_.swap(__t.__base_);
1126    }
1127#endif // _LIBCPP_STD_VER >= 23
1128};
1129
1130template <>
1131class _LIBCPP_TEMPLATE_VIS tuple<>
1132{
1133public:
1134    constexpr tuple() _NOEXCEPT = default;
1135    template <class _Alloc>
1136    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1137        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1138    template <class _Alloc>
1139    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1140        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1141    template <class _Up>
1142    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1143        tuple(array<_Up, 0>) _NOEXCEPT {}
1144    template <class _Alloc, class _Up>
1145    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1146        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1147    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1148    void swap(tuple&) _NOEXCEPT {}
1149#if _LIBCPP_STD_VER >= 23
1150    _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple&) const noexcept {}
1151#endif
1152};
1153
1154#if _LIBCPP_STD_VER >= 23
1155template <class... _TTypes, class... _UTypes, template<class> class _TQual, template<class> class _UQual>
1156    requires requires { typename tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>; }
1157struct basic_common_reference<tuple<_TTypes...>, tuple<_UTypes...>, _TQual, _UQual> {
1158    using type = tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>;
1159};
1160
1161template <class... _TTypes, class... _UTypes>
1162    requires requires { typename tuple<common_type_t<_TTypes, _UTypes>...>; }
1163struct common_type<tuple<_TTypes...>, tuple<_UTypes...>> {
1164    using type = tuple<common_type_t<_TTypes, _UTypes>...>;
1165};
1166#endif // _LIBCPP_STD_VER >= 23
1167
1168#if _LIBCPP_STD_VER >= 17
1169template <class ..._Tp>
1170tuple(_Tp...) -> tuple<_Tp...>;
1171template <class _Tp1, class _Tp2>
1172tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1173template <class _Alloc, class ..._Tp>
1174tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1175template <class _Alloc, class _Tp1, class _Tp2>
1176tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1177template <class _Alloc, class ..._Tp>
1178tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1179#endif
1180
1181template <class ..._Tp, __enable_if_t<__all<__is_swappable<_Tp>::value...>::value, int> = 0>
1182inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1183void
1184swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1185                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1186    {__t.swap(__u);}
1187
1188#if _LIBCPP_STD_VER >= 23
1189template <class... _Tp>
1190_LIBCPP_HIDE_FROM_ABI constexpr
1191enable_if_t<__all<is_swappable_v<const _Tp>...>::value, void>
1192swap(const tuple<_Tp...>& __lhs, const tuple<_Tp...>& __rhs)
1193        noexcept(__all<is_nothrow_swappable_v<const _Tp>...>::value) {
1194    __lhs.swap(__rhs);
1195}
1196#endif
1197
1198// get
1199
1200template <size_t _Ip, class ..._Tp>
1201inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1202typename tuple_element<_Ip, tuple<_Tp...> >::type&
1203get(tuple<_Tp...>& __t) _NOEXCEPT
1204{
1205    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1206    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1207}
1208
1209template <size_t _Ip, class ..._Tp>
1210inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1211const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1212get(const tuple<_Tp...>& __t) _NOEXCEPT
1213{
1214    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1215    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1216}
1217
1218template <size_t _Ip, class ..._Tp>
1219inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1220typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1221get(tuple<_Tp...>&& __t) _NOEXCEPT
1222{
1223    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1224    return static_cast<type&&>(
1225             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1226}
1227
1228template <size_t _Ip, class ..._Tp>
1229inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1230const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1231get(const tuple<_Tp...>&& __t) _NOEXCEPT
1232{
1233    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1234    return static_cast<const type&&>(
1235             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1236}
1237
1238#if _LIBCPP_STD_VER >= 14
1239
1240namespace __find_detail {
1241
1242static constexpr size_t __not_found = static_cast<size_t>(-1);
1243static constexpr size_t __ambiguous = __not_found - 1;
1244
1245inline _LIBCPP_INLINE_VISIBILITY
1246constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
1247    return !__matches ? __res :
1248        (__res == __not_found ? __curr_i : __ambiguous);
1249}
1250
1251template <size_t _Nx>
1252inline _LIBCPP_INLINE_VISIBILITY
1253constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1254  return __i == _Nx ? __not_found :
1255      __find_detail::__find_idx_return(__i, __find_detail::__find_idx(__i + 1, __matches), __matches[__i]);
1256}
1257
1258template <class _T1, class ..._Args>
1259struct __find_exactly_one_checked {
1260    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1261    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1262    static_assert(value != __not_found, "type not found in type list" );
1263    static_assert(value != __ambiguous, "type occurs more than once in type list");
1264};
1265
1266template <class _T1>
1267struct __find_exactly_one_checked<_T1> {
1268    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1269};
1270
1271} // namespace __find_detail
1272
1273template <typename _T1, typename... _Args>
1274struct __find_exactly_one_t
1275    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1276};
1277
1278template <class _T1, class... _Args>
1279inline _LIBCPP_INLINE_VISIBILITY
1280constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1281{
1282    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1283}
1284
1285template <class _T1, class... _Args>
1286inline _LIBCPP_INLINE_VISIBILITY
1287constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1288{
1289    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1290}
1291
1292template <class _T1, class... _Args>
1293inline _LIBCPP_INLINE_VISIBILITY
1294constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1295{
1296    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1297}
1298
1299template <class _T1, class... _Args>
1300inline _LIBCPP_INLINE_VISIBILITY
1301constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1302{
1303    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1304}
1305
1306#endif
1307
1308// tie
1309
1310template <class ..._Tp>
1311inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1312tuple<_Tp&...>
1313tie(_Tp&... __t) _NOEXCEPT
1314{
1315    return tuple<_Tp&...>(__t...);
1316}
1317
1318template <class _Up>
1319struct __ignore_t
1320{
1321    template <class _Tp>
1322    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1323    const __ignore_t& operator=(_Tp&&) const {return *this;}
1324};
1325
1326#  if _LIBCPP_STD_VER >= 17
1327inline constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1328#  else
1329namespace {
1330  constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1331} // namespace
1332#  endif
1333
1334template <class... _Tp>
1335inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1336tuple<typename __unwrap_ref_decay<_Tp>::type...>
1337make_tuple(_Tp&&... __t)
1338{
1339    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1340}
1341
1342template <class... _Tp>
1343inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1344tuple<_Tp&&...>
1345forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1346{
1347    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1348}
1349
1350template <size_t _Ip>
1351struct __tuple_equal
1352{
1353    template <class _Tp, class _Up>
1354    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1355    bool operator()(const _Tp& __x, const _Up& __y)
1356    {
1357        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1358    }
1359};
1360
1361template <>
1362struct __tuple_equal<0>
1363{
1364    template <class _Tp, class _Up>
1365    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1366    bool operator()(const _Tp&, const _Up&)
1367    {
1368        return true;
1369    }
1370};
1371
1372template <class ..._Tp, class ..._Up>
1373inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1374bool
1375operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1376{
1377    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1378    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1379}
1380
1381#if _LIBCPP_STD_VER >= 20
1382
1383// operator<=>
1384
1385template <class ..._Tp, class ..._Up, size_t ..._Is>
1386_LIBCPP_HIDE_FROM_ABI constexpr
1387auto
1388__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
1389    common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
1390    static_cast<void>(((__result = _VSTD::__synth_three_way(_VSTD::get<_Is>(__x), _VSTD::get<_Is>(__y)), __result != 0) || ...));
1391    return __result;
1392}
1393
1394template <class ..._Tp, class ..._Up>
1395requires (sizeof...(_Tp) == sizeof...(_Up))
1396_LIBCPP_HIDE_FROM_ABI constexpr
1397common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
1398operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1399{
1400    return _VSTD::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
1401}
1402
1403#else // _LIBCPP_STD_VER >= 20
1404
1405template <class ..._Tp, class ..._Up>
1406inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1407bool
1408operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1409{
1410    return !(__x == __y);
1411}
1412
1413template <size_t _Ip>
1414struct __tuple_less
1415{
1416    template <class _Tp, class _Up>
1417    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1418    bool operator()(const _Tp& __x, const _Up& __y)
1419    {
1420        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1421        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1422            return true;
1423        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1424            return false;
1425        return __tuple_less<_Ip-1>()(__x, __y);
1426    }
1427};
1428
1429template <>
1430struct __tuple_less<0>
1431{
1432    template <class _Tp, class _Up>
1433    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1434    bool operator()(const _Tp&, const _Up&)
1435    {
1436        return false;
1437    }
1438};
1439
1440template <class ..._Tp, class ..._Up>
1441inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1442bool
1443operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1444{
1445    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1446    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1447}
1448
1449template <class ..._Tp, class ..._Up>
1450inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1451bool
1452operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1453{
1454    return __y < __x;
1455}
1456
1457template <class ..._Tp, class ..._Up>
1458inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1459bool
1460operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1461{
1462    return !(__x < __y);
1463}
1464
1465template <class ..._Tp, class ..._Up>
1466inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1467bool
1468operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1469{
1470    return !(__y < __x);
1471}
1472
1473#endif // _LIBCPP_STD_VER >= 20
1474
1475// tuple_cat
1476
1477template <class _Tp, class _Up> struct __tuple_cat_type;
1478
1479template <class ..._Ttypes, class ..._Utypes>
1480struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1481{
1482    typedef _LIBCPP_NODEBUG tuple<_Ttypes..., _Utypes...> type;
1483};
1484
1485template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1486struct __tuple_cat_return_1
1487{
1488};
1489
1490template <class ..._Types, class _Tuple0>
1491struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1492{
1493  using type _LIBCPP_NODEBUG = typename __tuple_cat_type<
1494      tuple<_Types...>,
1495      typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type
1496    >::type;
1497};
1498
1499template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1500struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1501    : public __tuple_cat_return_1<
1502                 typename __tuple_cat_type<
1503                     tuple<_Types...>,
1504                     typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type
1505                 >::type,
1506                 __tuple_like_ext<__libcpp_remove_reference_t<_Tuple1> >::value,
1507                 _Tuple1, _Tuples...>
1508{
1509};
1510
1511template <class ..._Tuples> struct __tuple_cat_return;
1512
1513template <class _Tuple0, class ..._Tuples>
1514struct __tuple_cat_return<_Tuple0, _Tuples...>
1515    : public __tuple_cat_return_1<tuple<>,
1516         __tuple_like_ext<__libcpp_remove_reference_t<_Tuple0> >::value, _Tuple0,
1517                                                                     _Tuples...>
1518{
1519};
1520
1521template <>
1522struct __tuple_cat_return<>
1523{
1524    typedef _LIBCPP_NODEBUG tuple<> type;
1525};
1526
1527inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1528tuple<>
1529tuple_cat()
1530{
1531    return tuple<>();
1532}
1533
1534template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1535struct __tuple_cat_return_ref_imp;
1536
1537template <class ..._Types, size_t ..._I0, class _Tuple0>
1538struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1539{
1540    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1541    typedef tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_I0, _T0>::type>&&...> type;
1542};
1543
1544template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1545struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1546                                  _Tuple0, _Tuple1, _Tuples...>
1547    : public __tuple_cat_return_ref_imp<
1548         tuple<_Types..., __apply_cv_t<_Tuple0,
1549                                       typename tuple_element<_I0, __libcpp_remove_reference_t<_Tuple0>>::type>&&...>,
1550         typename __make_tuple_indices<tuple_size<__libcpp_remove_reference_t<_Tuple1> >::value>::type,
1551         _Tuple1, _Tuples...>
1552{
1553};
1554
1555template <class _Tuple0, class ..._Tuples>
1556struct __tuple_cat_return_ref
1557    : public __tuple_cat_return_ref_imp<tuple<>,
1558               typename __make_tuple_indices<
1559                        tuple_size<__libcpp_remove_reference_t<_Tuple0> >::value
1560               >::type, _Tuple0, _Tuples...>
1561{
1562};
1563
1564template <class _Types, class _I0, class _J0>
1565struct __tuple_cat;
1566
1567template <class ..._Types, size_t ..._I0, size_t ..._J0>
1568struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1569{
1570    template <class _Tuple0>
1571    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1572    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1573    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1574    {
1575        (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1576        return _VSTD::forward_as_tuple(
1577            _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1578            _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1579    }
1580
1581    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1582    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1583    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1584    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1585    {
1586        (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1587        typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1588        typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple1> _T1;
1589        return __tuple_cat<tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_J0, _T0>::type>&&...>,
1590                           typename __make_tuple_indices<sizeof...(_Types) + tuple_size<_T0>::value>::type,
1591                           typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1592            _VSTD::forward_as_tuple(
1593                _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1594                _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...),
1595            _VSTD::forward<_Tuple1>(__t1), _VSTD::forward<_Tuples>(__tpls)...);
1596    }
1597};
1598
1599template <class _Tuple0, class... _Tuples>
1600inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
1601typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1602tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1603{
1604    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1605    return __tuple_cat<tuple<>, __tuple_indices<>,
1606                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1607                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1608                                            _VSTD::forward<_Tuples>(__tpls)...);
1609}
1610
1611template <class ..._Tp, class _Alloc>
1612struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1613    : true_type {};
1614
1615template <class _T1, class _T2>
1616template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1617inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
1618pair<_T1, _T2>::pair(piecewise_construct_t,
1619                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1620                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1621    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1622      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1623{
1624}
1625
1626#if _LIBCPP_STD_VER >= 17
1627template <class _Tp>
1628inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1629
1630#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1631
1632template <class _Fn, class _Tuple, size_t ..._Id>
1633inline _LIBCPP_INLINE_VISIBILITY
1634constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1635                                            __tuple_indices<_Id...>)
1636_LIBCPP_NOEXCEPT_RETURN(
1637    _VSTD::__invoke(
1638        _VSTD::forward<_Fn>(__f),
1639        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1640)
1641
1642template <class _Fn, class _Tuple>
1643inline _LIBCPP_INLINE_VISIBILITY
1644constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1645_LIBCPP_NOEXCEPT_RETURN(
1646    _VSTD::__apply_tuple_impl(
1647        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1648        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1649)
1650
1651template <class _Tp, class _Tuple, size_t... _Idx>
1652inline _LIBCPP_INLINE_VISIBILITY
1653constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1654_LIBCPP_NOEXCEPT_RETURN(
1655    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1656)
1657
1658template <class _Tp, class _Tuple>
1659inline _LIBCPP_INLINE_VISIBILITY
1660constexpr _Tp make_from_tuple(_Tuple&& __t)
1661_LIBCPP_NOEXCEPT_RETURN(
1662    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1663        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1664)
1665
1666#undef _LIBCPP_NOEXCEPT_RETURN
1667
1668#endif // _LIBCPP_STD_VER >= 17
1669
1670#endif // !defined(_LIBCPP_CXX03_LANG)
1671
1672_LIBCPP_END_NAMESPACE_STD
1673
1674_LIBCPP_POP_MACROS
1675
1676#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1677#  include <exception>
1678#  include <iosfwd>
1679#  include <new>
1680#  include <type_traits>
1681#  include <typeinfo>
1682#  include <utility>
1683#endif
1684
1685#endif // _LIBCPP_TUPLE
1686