xref: /freebsd/contrib/llvm-project/libcxx/include/tuple (revision e63d20b70ee1dbee9b075f29de6f30cdcfe1abe1)
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// clang-format off
14
15/*
16    tuple synopsis
17
18namespace std
19{
20
21template <class... T>
22class tuple {
23public:
24    explicit(see-below) constexpr tuple();
25    explicit(see-below) tuple(const T&...);  // constexpr in C++14
26    template <class... U>
27        explicit(see-below) tuple(U&&...);  // constexpr in C++14
28    tuple(const tuple&) = default;
29    tuple(tuple&&) = default;
30
31    template<class... UTypes>
32        constexpr explicit(see-below) tuple(tuple<UTypes...>&);  // C++23
33    template <class... U>
34        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
35    template <class... U>
36        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
37    template<class... UTypes>
38        constexpr explicit(see-below) tuple(const tuple<UTypes...>&&); // C++23
39
40    template<class U1, class U2>
41        constexpr explicit(see-below) tuple(pair<U1, U2>&);  // iff sizeof...(Types) == 2 // C++23
42    template <class U1, class U2>
43        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
44    template <class U1, class U2>
45        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
46    template<class U1, class U2>
47        constexpr explicit(see-below) tuple(const pair<U1, U2>&&);  // iff sizeof...(Types) == 2 // C++23
48
49    // allocator-extended constructors
50    template <class Alloc>
51        tuple(allocator_arg_t, const Alloc& a);
52    template <class Alloc>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
54    template <class Alloc, class... U>
55        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
56    template <class Alloc>
57        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
58    template <class Alloc>
59        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
60    template<class Alloc, class... UTypes>
61        constexpr explicit(see-below)
62          tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&);                      // C++23
63    template <class Alloc, class... U>
64        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
65    template <class Alloc, class... U>
66        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
67    template<class Alloc, class... UTypes>
68        constexpr explicit(see-below)
69          tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&&);               // C++23
70    template<class Alloc, class U1, class U2>
71        constexpr explicit(see-below)
72          tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&);                          // C++23
73    template <class Alloc, class U1, class U2>
74        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
75    template <class Alloc, class U1, class U2>
76        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
77    template<class Alloc, class U1, class U2>
78        constexpr explicit(see-below)
79          tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&&);                   // C++23
80
81    tuple& operator=(const tuple&);                                                       // constexpr in C++20
82    constexpr const tuple& operator=(const tuple&) const;                                 // C++23
83    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
84    constexpr const tuple& operator=(tuple&&) const;                                      // C++23
85    template <class... U>
86        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
87    template<class... UTypes>
88        constexpr const tuple& operator=(const tuple<UTypes...>&) const;                  // C++23
89    template <class... U>
90        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
91    template<class... UTypes>
92        constexpr const tuple& operator=(tuple<UTypes...>&&) const;                       // C++23
93    template <class U1, class U2>
94        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
95    template<class U1, class U2>
96        constexpr const tuple& operator=(const pair<U1, U2>&) const;   // iff sizeof...(Types) == 2 // C++23
97    template <class U1, class U2>
98        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
99    template<class U1, class U2>
100        constexpr const tuple& operator=(pair<U1, U2>&&) const;  // iff sizeof...(Types) == 2 // C++23
101
102    template<class U, size_t N>
103        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
104    template<class U, size_t N>
105        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
106
107    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
108    constexpr void swap(const tuple&) const noexcept(see-below);                          // C++23
109};
110
111
112template<class... TTypes, class... UTypes, template<class> class TQual, template<class> class UQual> // since C++23
113  requires requires { typename tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>; }
114struct basic_common_reference<tuple<TTypes...>, tuple<UTypes...>, TQual, UQual> {
115  using type = tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>;
116};
117
118template<class... TTypes, class... UTypes>                                // since C++23
119  requires requires { typename tuple<common_type_t<TTypes, UTypes>...>; }
120struct common_type<tuple<TTypes...>, tuple<UTypes...>> {
121  using type = tuple<common_type_t<TTypes, UTypes>...>;
122};
123
124template <class ...T>
125tuple(T...) -> tuple<T...>;                                         // since C++17
126template <class T1, class T2>
127tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
128template <class Alloc, class ...T>
129tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
130template <class Alloc, class T1, class T2>
131tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
132template <class Alloc, class ...T>
133tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
134
135inline constexpr unspecified ignore;
136
137template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
138template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
139template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
140template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
141
142// [tuple.apply], calling a function with a tuple of arguments:
143template <class F, class Tuple>
144  constexpr decltype(auto) apply(F&& f, Tuple&& t) noexcept(see below);  // C++17 noexcept since C++23
145template <class T, class Tuple>
146  constexpr T make_from_tuple(Tuple&& t); // C++17
147
148// 20.4.1.4, tuple helper classes:
149template <class T> struct tuple_size; // undefined
150template <class... T> struct tuple_size<tuple<T...>>;
151template <class T>
152 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
153template <size_t I, class T> struct tuple_element; // undefined
154template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
155template <size_t I, class T>
156  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
157
158// 20.4.1.5, element access:
159template <size_t I, class... T>
160    typename tuple_element<I, tuple<T...>>::type&
161    get(tuple<T...>&) noexcept; // constexpr in C++14
162template <size_t I, class... T>
163    const typename tuple_element<I, tuple<T...>>::type&
164    get(const tuple<T...>&) noexcept; // constexpr in C++14
165template <size_t I, class... T>
166    typename tuple_element<I, tuple<T...>>::type&&
167    get(tuple<T...>&&) noexcept; // constexpr in C++14
168template <size_t I, class... T>
169    const typename tuple_element<I, tuple<T...>>::type&&
170    get(const tuple<T...>&&) noexcept; // constexpr in C++14
171
172template <class T1, class... T>
173    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
174template <class T1, class... T>
175    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
176template <class T1, class... T>
177    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
178template <class T1, class... T>
179    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
180
181// 20.4.1.6, relational operators:
182template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
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> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
187template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
188template<class... T, class... U>
189  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
190    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
191
192template <class... Types, class Alloc>
193  struct uses_allocator<tuple<Types...>, Alloc>;
194
195template <class... Types>
196  void
197  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
198
199template <class... Types>
200  constexpr void swap(const tuple<Types...>& x, const tuple<Types...>& y) noexcept(see-below);   // C++23
201
202}  // std
203
204*/
205
206// clang-format on
207
208#include <__assert> // all public C++ headers provide the assertion handler
209#include <__compare/common_comparison_category.h>
210#include <__compare/synth_three_way.h>
211#include <__config>
212#include <__functional/invoke.h>
213#include <__fwd/array.h>
214#include <__fwd/get.h>
215#include <__fwd/tuple.h>
216#include <__memory/allocator_arg_t.h>
217#include <__memory/uses_allocator.h>
218#include <__tuple/make_tuple_types.h>
219#include <__tuple/sfinae_helpers.h>
220#include <__tuple/tuple_element.h>
221#include <__tuple/tuple_indices.h>
222#include <__tuple/tuple_like_ext.h>
223#include <__tuple/tuple_size.h>
224#include <__tuple/tuple_types.h>
225#include <__type_traits/apply_cv.h>
226#include <__type_traits/common_reference.h>
227#include <__type_traits/common_type.h>
228#include <__type_traits/conditional.h>
229#include <__type_traits/conjunction.h>
230#include <__type_traits/copy_cvref.h>
231#include <__type_traits/disjunction.h>
232#include <__type_traits/is_arithmetic.h>
233#include <__type_traits/is_assignable.h>
234#include <__type_traits/is_constructible.h>
235#include <__type_traits/is_convertible.h>
236#include <__type_traits/is_copy_assignable.h>
237#include <__type_traits/is_copy_constructible.h>
238#include <__type_traits/is_default_constructible.h>
239#include <__type_traits/is_empty.h>
240#include <__type_traits/is_final.h>
241#include <__type_traits/is_implicitly_default_constructible.h>
242#include <__type_traits/is_move_assignable.h>
243#include <__type_traits/is_move_constructible.h>
244#include <__type_traits/is_nothrow_assignable.h>
245#include <__type_traits/is_nothrow_constructible.h>
246#include <__type_traits/is_nothrow_copy_assignable.h>
247#include <__type_traits/is_nothrow_copy_constructible.h>
248#include <__type_traits/is_nothrow_default_constructible.h>
249#include <__type_traits/is_nothrow_move_assignable.h>
250#include <__type_traits/is_reference.h>
251#include <__type_traits/is_same.h>
252#include <__type_traits/is_swappable.h>
253#include <__type_traits/lazy.h>
254#include <__type_traits/maybe_const.h>
255#include <__type_traits/nat.h>
256#include <__type_traits/negation.h>
257#include <__type_traits/remove_cvref.h>
258#include <__type_traits/remove_reference.h>
259#include <__type_traits/unwrap_ref.h>
260#include <__utility/forward.h>
261#include <__utility/integer_sequence.h>
262#include <__utility/move.h>
263#include <__utility/pair.h>
264#include <__utility/piecewise_construct.h>
265#include <__utility/swap.h>
266#include <cstddef>
267#include <version>
268
269// standard-mandated includes
270
271// [tuple.syn]
272#include <compare>
273
274#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
275#  pragma GCC system_header
276#endif
277
278_LIBCPP_PUSH_MACROS
279#include <__undef_macros>
280
281_LIBCPP_BEGIN_NAMESPACE_STD
282
283#ifndef _LIBCPP_CXX03_LANG
284
285// __tuple_leaf
286
287template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value >
288class __tuple_leaf;
289
290template <size_t _Ip, class _Hp, bool _Ep>
291inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
292swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
293    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value) {
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 void
299swap(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  _Hp __value_;
307
308  template <class _Tp>
309  static _LIBCPP_HIDE_FROM_ABI constexpr bool __can_bind_reference() {
310#  if __has_keyword(__reference_binds_to_temporary)
311    return !__reference_binds_to_temporary(_Hp, _Tp);
312#  else
313    return true;
314#  endif
315  }
316
317  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&);
318
319public:
320  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_() {
321    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
322  }
323
324  template <class _Alloc>
325  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) : __value_() {
326    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
327  }
328
329  template <class _Alloc>
330  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
331      : __value_(allocator_arg_t(), __a) {
332    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
333  }
334
335  template <class _Alloc>
336  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : __value_(__a) {
337    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
338  }
339
340  template <class _Tp,
341            class = __enable_if_t<
342                _And< _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value > >
343  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t)
344      _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
345      : __value_(std::forward<_Tp>(__t)) {
346    static_assert(__can_bind_reference<_Tp&&>(),
347                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
348  }
349
350  template <class _Tp, class _Alloc>
351  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
352      integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
353      : __value_(std::forward<_Tp>(__t)) {
354    static_assert(__can_bind_reference<_Tp&&>(),
355                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
356  }
357
358  template <class _Tp, class _Alloc>
359  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
360      integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
361      : __value_(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {
362    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
363  }
364
365  template <class _Tp, class _Alloc>
366  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
367      integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
368      : __value_(std::forward<_Tp>(__t), __a) {
369    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
370  }
371
372  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(const __tuple_leaf& __t) = default;
373  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(__tuple_leaf&& __t)      = default;
374
375  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(__tuple_leaf& __t)
376      _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value) {
377    std::swap(*this, __t);
378    return 0;
379  }
380
381  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __t) const
382      _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
383    std::swap(*this, __t);
384    return 0;
385  }
386
387  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return __value_; }
388  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT { return __value_; }
389};
390
391template <size_t _Ip, class _Hp>
392class __tuple_leaf<_Ip, _Hp, true> : private _Hp {
393  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&);
394
395public:
396  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
397
398  template <class _Alloc>
399  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
400
401  template <class _Alloc>
402  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
403      : _Hp(allocator_arg_t(), __a) {}
404
405  template <class _Alloc>
406  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : _Hp(__a) {}
407
408  template <class _Tp,
409            class = __enable_if_t<
410                _And< _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value > >
411  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t)
412      _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
413      : _Hp(std::forward<_Tp>(__t)) {}
414
415  template <class _Tp, class _Alloc>
416  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
417      : _Hp(std::forward<_Tp>(__t)) {}
418
419  template <class _Tp, class _Alloc>
420  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
421      : _Hp(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {}
422
423  template <class _Tp, class _Alloc>
424  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
425      : _Hp(std::forward<_Tp>(__t), __a) {}
426
427  __tuple_leaf(__tuple_leaf const&) = default;
428  __tuple_leaf(__tuple_leaf&&)      = default;
429
430  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(__tuple_leaf& __t)
431      _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value) {
432    std::swap(*this, __t);
433    return 0;
434  }
435
436  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __rhs) const
437      _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
438    std::swap(*this, __rhs);
439    return 0;
440  }
441
442  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return static_cast<_Hp&>(*this); }
443  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT {
444    return static_cast<const _Hp&>(*this);
445  }
446};
447
448template <class... _Tp>
449_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void __swallow(_Tp&&...) _NOEXCEPT {}
450
451template <class _Tp>
452struct __all_default_constructible;
453
454template <class... _Tp>
455struct __all_default_constructible<__tuple_types<_Tp...>> : __all<is_default_constructible<_Tp>::value...> {};
456
457// __tuple_impl
458
459template <class _Indx, class... _Tp>
460struct __tuple_impl;
461
462template <size_t... _Indx, class... _Tp>
463struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
464    : public __tuple_leaf<_Indx, _Tp>... {
465  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_impl()
466      _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
467
468  template <size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
469  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
470      __tuple_indices<_Uf...>, __tuple_types<_Tf...>, __tuple_indices<_Ul...>, __tuple_types<_Tl...>, _Up&&... __u)
471      _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
472                  __all<is_nothrow_default_constructible<_Tl>::value...>::value))
473      : __tuple_leaf<_Uf, _Tf>(std::forward<_Up>(__u))..., __tuple_leaf<_Ul, _Tl>()... {}
474
475  template <class _Alloc, size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
476  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
477      allocator_arg_t,
478      const _Alloc& __a,
479      __tuple_indices<_Uf...>,
480      __tuple_types<_Tf...>,
481      __tuple_indices<_Ul...>,
482      __tuple_types<_Tl...>,
483      _Up&&... __u)
484      : __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a, std::forward<_Up>(__u))...,
485        __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)... {}
486
487  template <class _Tuple, class = __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value> >
488  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(_Tuple&& __t) _NOEXCEPT_(
489      (__all<is_nothrow_constructible<
490           _Tp,
491           typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
492      : __tuple_leaf<_Indx, _Tp>(
493            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
494                std::get<_Indx>(__t)))... {}
495
496  template <class _Alloc, class _Tuple, class = __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value> >
497  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
498      : __tuple_leaf<_Indx, _Tp>(
499            __uses_alloc_ctor<_Tp,
500                              _Alloc,
501                              typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(),
502            __a,
503            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
504                std::get<_Indx>(__t)))... {}
505
506  __tuple_impl(const __tuple_impl&) = default;
507  __tuple_impl(__tuple_impl&&)      = default;
508
509  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(__tuple_impl& __t)
510      _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
511    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
512  }
513
514  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(const __tuple_impl& __t) const
515      _NOEXCEPT_(__all<__is_nothrow_swappable<const _Tp>::value...>::value) {
516    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t))...);
517  }
518};
519
520template <class _Dest, class _Source, size_t... _Np>
521_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
522__memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
523  std::__swallow(((std::get<_Np>(__dest) = std::get<_Np>(__source)), void(), 0)...);
524}
525
526template <class _Dest, class _Source, class... _Up, size_t... _Np>
527_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
528__memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
529  std::__swallow(((std::get<_Np>(__dest) = std::forward<_Up>(std::get<_Np>(__source))), void(), 0)...);
530}
531
532template <class... _Tp>
533class _LIBCPP_TEMPLATE_VIS tuple {
534  typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
535
536  _BaseT __base_;
537
538  template <size_t _Jp, class... _Up>
539  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
540  template <size_t _Jp, class... _Up>
541  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&
542  get(const tuple<_Up...>&) _NOEXCEPT;
543  template <size_t _Jp, class... _Up>
544  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type&&
545  get(tuple<_Up...>&&) _NOEXCEPT;
546  template <size_t _Jp, class... _Up>
547  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&&
548  get(const tuple<_Up...>&&) _NOEXCEPT;
549
550public:
551  // [tuple.cnstr]
552
553  _LIBCPP_DIAGNOSTIC_PUSH
554  _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions")
555  _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions")
556
557  // tuple() constructors (including allocator_arg_t variants)
558  template <template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
559            template <class...> class _IsDefault                   = is_default_constructible,
560            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
561  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value) tuple()
562      _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value) {}
563
564  template <class _Alloc,
565            template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
566            template <class...> class _IsDefault                   = is_default_constructible,
567            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
568  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value)
569      tuple(allocator_arg_t, _Alloc const& __a)
570      : __base_(allocator_arg_t(),
571                __a,
572                __tuple_indices<>(),
573                __tuple_types<>(),
574                typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
575                __tuple_types<_Tp...>()) {}
576
577  // tuple(const T&...) constructors (including allocator_arg_t variants)
578  template <template <class...> class _And = _And,
579            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
580  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
581      _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value) tuple(const _Tp&... __t)
582      _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
583      : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
584                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
585                typename __make_tuple_indices<0>::type(),
586                typename __make_tuple_types<tuple, 0>::type(),
587                __t...) {}
588
589  template <class _Alloc,
590            template <class...> class _And = _And,
591            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
592  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
593      _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value)
594      tuple(allocator_arg_t, const _Alloc& __a, const _Tp&... __t)
595      : __base_(allocator_arg_t(),
596                __a,
597                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
598                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
599                typename __make_tuple_indices<0>::type(),
600                typename __make_tuple_types<tuple, 0>::type(),
601                __t...) {}
602
603  // tuple(U&& ...) constructors (including allocator_arg_t variants)
604  template <class... _Up>
605  struct _IsThisTuple : false_type {};
606  template <class _Up>
607  struct _IsThisTuple<_Up> : is_same<__remove_cvref_t<_Up>, tuple> {};
608
609  template <class... _Up>
610  struct _EnableUTypesCtor
611      : _And< _BoolConstant<sizeof...(_Tp) >= 1>,
612              _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
613              is_constructible<_Tp, _Up>... > {};
614
615  template <class... _Up,
616            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
617                           int> = 0>
618  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
619      tuple(_Up&&... __u) _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
620      : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
621                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
622                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
623                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
624                std::forward<_Up>(__u)...) {}
625
626  template <class _Alloc,
627            class... _Up,
628            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
629                           int> = 0>
630  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
631      tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
632      : __base_(allocator_arg_t(),
633                __a,
634                typename __make_tuple_indices<sizeof...(_Up)>::type(),
635                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
636                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
637                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
638                std::forward<_Up>(__u)...) {}
639
640  // Copy and move constructors (including the allocator_arg_t variants)
641  tuple(const tuple&) = default;
642  tuple(tuple&&)      = default;
643
644  template <class _Alloc,
645            template <class...> class _And                                  = _And,
646            __enable_if_t< _And<is_copy_constructible<_Tp>...>::value, int> = 0>
647  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
648      : __base_(allocator_arg_t(), __alloc, __t) {}
649
650  template <class _Alloc,
651            template <class...> class _And                                  = _And,
652            __enable_if_t< _And<is_move_constructible<_Tp>...>::value, int> = 0>
653  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
654      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
655
656  // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
657
658  template <class _OtherTuple, class _DecayedOtherTuple = __remove_cvref_t<_OtherTuple>, class = void>
659  struct _EnableCtorFromUTypesTuple : false_type {};
660
661  template <class _OtherTuple, class... _Up>
662  struct _EnableCtorFromUTypesTuple<
663      _OtherTuple,
664      tuple<_Up...>,
665      // the length of the packs needs to checked first otherwise the 2 packs cannot be expanded simultaneously below
666      __enable_if_t<sizeof...(_Up) == sizeof...(_Tp)>>
667      : _And<
668            // the two conditions below are not in spec. The purpose is to disable the UTypes Ctor when copy/move Ctor
669            // can work. Otherwise, is_constructible can trigger hard error in those cases
670            // https://godbolt.org/z/M94cGdKcE
671            _Not<is_same<_OtherTuple, const tuple&> >,
672            _Not<is_same<_OtherTuple, tuple&&> >,
673            is_constructible<_Tp, __copy_cvref_t<_OtherTuple, _Up> >...,
674            _Lazy<_Or,
675                  _BoolConstant<sizeof...(_Tp) != 1>,
676                  // _Tp and _Up are 1-element packs - the pack expansions look
677                  // weird to avoid tripping up the type traits in degenerate cases
678                  _Lazy<_And,
679                        _Not<is_same<_Tp, _Up> >...,
680                        _Not<is_convertible<_OtherTuple, _Tp> >...,
681                        _Not<is_constructible<_Tp, _OtherTuple> >... > > > {};
682
683  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
684  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
685      _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value) tuple(const tuple<_Up...>& __t)
686      _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
687      : __base_(__t) {}
688
689  template <class... _Up,
690            class _Alloc,
691            __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
692  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
693      _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value)
694      tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
695      : __base_(allocator_arg_t(), __a, __t) {}
696
697#  if _LIBCPP_STD_VER >= 23
698  // tuple(tuple<U...>&) constructors (including allocator_arg_t variants)
699
700  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
701  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value) tuple(tuple<_Up...>& __t)
702      : __base_(__t) {}
703
704  template <class _Alloc, class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
705  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value)
706      tuple(allocator_arg_t, const _Alloc& __alloc, tuple<_Up...>& __t)
707      : __base_(allocator_arg_t(), __alloc, __t) {}
708#  endif // _LIBCPP_STD_VER >= 23
709
710  // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
711  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
712  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
713      tuple(tuple<_Up...>&& __t) _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
714      : __base_(std::move(__t)) {}
715
716  template <class _Alloc,
717            class... _Up,
718            __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
719  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
720      tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
721      : __base_(allocator_arg_t(), __a, std::move(__t)) {}
722
723#  if _LIBCPP_STD_VER >= 23
724  // tuple(const tuple<U...>&&) constructors (including allocator_arg_t variants)
725
726  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
727  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
728      tuple(const tuple<_Up...>&& __t)
729      : __base_(std::move(__t)) {}
730
731  template <class _Alloc,
732            class... _Up,
733            enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
734  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
735      tuple(allocator_arg_t, const _Alloc& __alloc, const tuple<_Up...>&& __t)
736      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
737#  endif // _LIBCPP_STD_VER >= 23
738
739  // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
740
741  template <template <class...> class _Pred,
742            class _Pair,
743            class _DecayedPair = __remove_cvref_t<_Pair>,
744            class _Tuple       = tuple>
745  struct _CtorPredicateFromPair : false_type {};
746
747  template <template <class...> class _Pred, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
748  struct _CtorPredicateFromPair<_Pred, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
749      : _And< _Pred<_Tp1, __copy_cvref_t<_Pair, _Up1> >, _Pred<_Tp2, __copy_cvref_t<_Pair, _Up2> > > {};
750
751  template <class _Pair>
752  struct _EnableCtorFromPair : _CtorPredicateFromPair<is_constructible, _Pair> {};
753
754  template <class _Pair>
755  struct _NothrowConstructibleFromPair : _CtorPredicateFromPair<is_nothrow_constructible, _Pair> {};
756
757  template <class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
758  struct _BothImplicitlyConvertible : false_type {};
759
760  template <class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
761  struct _BothImplicitlyConvertible<_Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
762      : _And< is_convertible<__copy_cvref_t<_Pair, _Up1>, _Tp1>, is_convertible<__copy_cvref_t<_Pair, _Up2>, _Tp2> > {};
763
764  template <class _Up1,
765            class _Up2,
766            template <class...> class _And                                                   = _And,
767            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
768  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
769      _Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value) tuple(const pair<_Up1, _Up2>& __p)
770      _NOEXCEPT_((_NothrowConstructibleFromPair<const pair<_Up1, _Up2>&>::value))
771      : __base_(__p) {}
772
773  template <class _Alloc,
774            class _Up1,
775            class _Up2,
776            template <class...> class _And                                                   = _And,
777            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
778  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
779      _Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value)
780      tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
781      : __base_(allocator_arg_t(), __a, __p) {}
782
783#  if _LIBCPP_STD_VER >= 23
784  // tuple(pair<U1, U2>&) constructors (including allocator_arg_t variants)
785
786  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<pair<_U1, _U2>&>::value>* = nullptr>
787  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
788      tuple(pair<_U1, _U2>& __p)
789      : __base_(__p) {}
790
791  template <class _Alloc,
792            class _U1,
793            class _U2,
794            enable_if_t< _EnableCtorFromPair<std::pair<_U1, _U2>&>::value>* = nullptr>
795  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
796      tuple(allocator_arg_t, const _Alloc& __alloc, pair<_U1, _U2>& __p)
797      : __base_(allocator_arg_t(), __alloc, __p) {}
798#  endif
799
800  // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
801
802  template <class _Up1,
803            class _Up2,
804            template <class...> class _And                                              = _And,
805            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
806  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
807      _Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value) tuple(pair<_Up1, _Up2>&& __p)
808      _NOEXCEPT_((_NothrowConstructibleFromPair<pair<_Up1, _Up2>&&>::value))
809      : __base_(std::move(__p)) {}
810
811  template <class _Alloc,
812            class _Up1,
813            class _Up2,
814            template <class...> class _And                                              = _And,
815            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
816  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
817      _Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value)
818      tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
819      : __base_(allocator_arg_t(), __a, std::move(__p)) {}
820
821#  if _LIBCPP_STD_VER >= 23
822  // tuple(const pair<U1, U2>&&) constructors (including allocator_arg_t variants)
823
824  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
825  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
826      tuple(const pair<_U1, _U2>&& __p)
827      : __base_(std::move(__p)) {}
828
829  template <class _Alloc,
830            class _U1,
831            class _U2,
832            enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
833  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
834      tuple(allocator_arg_t, const _Alloc& __alloc, const pair<_U1, _U2>&& __p)
835      : __base_(allocator_arg_t(), __alloc, std::move(__p)) {}
836#  endif // _LIBCPP_STD_VER >= 23
837
838  _LIBCPP_DIAGNOSTIC_POP
839
840  // [tuple.assign]
841  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
842  operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
843      _NOEXCEPT_((_And<is_nothrow_copy_assignable<_Tp>...>::value)) {
844    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
845    return *this;
846  }
847
848#  if _LIBCPP_STD_VER >= 23
849  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple const& __tuple) const
850    requires(_And<is_copy_assignable<const _Tp>...>::value)
851  {
852    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
853    return *this;
854  }
855
856  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple&& __tuple) const
857    requires(_And<is_assignable<const _Tp&, _Tp>...>::value)
858  {
859    std::__memberwise_forward_assign(
860        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
861    return *this;
862  }
863#  endif // _LIBCPP_STD_VER >= 23
864
865  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
866  operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
867      _NOEXCEPT_((_And<is_nothrow_move_assignable<_Tp>...>::value)) {
868    std::__memberwise_forward_assign(
869        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
870    return *this;
871  }
872
873  template <
874      class... _Up,
875      __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up const&>... >::value,
876                     int> = 0>
877  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(tuple<_Up...> const& __tuple)
878      _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value)) {
879    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
880    return *this;
881  }
882
883  template <class... _Up,
884            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up>... >::value,
885                           int> = 0>
886  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(tuple<_Up...>&& __tuple)
887      _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value)) {
888    std::__memberwise_forward_assign(
889        *this, std::move(__tuple), __tuple_types<_Up...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
890    return *this;
891  }
892
893#  if _LIBCPP_STD_VER >= 23
894  template <class... _UTypes,
895            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
896                              is_assignable<const _Tp&, const _UTypes&>...>::value>* = nullptr>
897  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const tuple<_UTypes...>& __u) const {
898    std::__memberwise_copy_assign(*this, __u, typename __make_tuple_indices<sizeof...(_Tp)>::type());
899    return *this;
900  }
901
902  template <class... _UTypes,
903            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
904                              is_assignable<const _Tp&, _UTypes>...>::value>* = nullptr>
905  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple<_UTypes...>&& __u) const {
906    std::__memberwise_forward_assign(
907        *this, __u, __tuple_types<_UTypes...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
908    return *this;
909  }
910#  endif // _LIBCPP_STD_VER >= 23
911
912  template <template <class...> class _Pred,
913            bool _Const,
914            class _Pair,
915            class _DecayedPair = __remove_cvref_t<_Pair>,
916            class _Tuple       = tuple>
917  struct _AssignPredicateFromPair : false_type {};
918
919  template <template <class...> class _Pred, bool _Const, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
920  struct _AssignPredicateFromPair<_Pred, _Const, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
921      : _And<_Pred<__maybe_const<_Const, _Tp1>&, __copy_cvref_t<_Pair, _Up1> >,
922             _Pred<__maybe_const<_Const, _Tp2>&, __copy_cvref_t<_Pair, _Up2> > > {};
923
924  template <bool _Const, class _Pair>
925  struct _EnableAssignFromPair : _AssignPredicateFromPair<is_assignable, _Const, _Pair> {};
926
927  template <bool _Const, class _Pair>
928  struct _NothrowAssignFromPair : _AssignPredicateFromPair<is_nothrow_assignable, _Const, _Pair> {};
929
930#  if _LIBCPP_STD_VER >= 23
931  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, const pair<_U1, _U2>&>::value>* = nullptr>
932  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const pair<_U1, _U2>& __pair) const
933      noexcept(_NothrowAssignFromPair<true, const pair<_U1, _U2>&>::value) {
934    std::get<0>(*this) = __pair.first;
935    std::get<1>(*this) = __pair.second;
936    return *this;
937  }
938
939  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, pair<_U1, _U2>&&>::value>* = nullptr>
940  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(pair<_U1, _U2>&& __pair) const
941      noexcept(_NothrowAssignFromPair<true, pair<_U1, _U2>&&>::value) {
942    std::get<0>(*this) = std::move(__pair.first);
943    std::get<1>(*this) = std::move(__pair.second);
944    return *this;
945  }
946#  endif // _LIBCPP_STD_VER >= 23
947
948  template <class _Up1,
949            class _Up2,
950            __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2> const&>::value, int> = 0>
951  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(pair<_Up1, _Up2> const& __pair)
952      _NOEXCEPT_((_NothrowAssignFromPair<false, pair<_Up1, _Up2> const&>::value)) {
953    std::get<0>(*this) = __pair.first;
954    std::get<1>(*this) = __pair.second;
955    return *this;
956  }
957
958  template <class _Up1, class _Up2, __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2>&&>::value, int> = 0>
959  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(pair<_Up1, _Up2>&& __pair)
960      _NOEXCEPT_((_NothrowAssignFromPair<false, pair<_Up1, _Up2>&&>::value)) {
961    std::get<0>(*this) = std::forward<_Up1>(__pair.first);
962    std::get<1>(*this) = std::forward<_Up2>(__pair.second);
963    return *this;
964  }
965
966  // EXTENSION
967  template <
968      class _Up,
969      size_t _Np,
970      class = __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up const&>... >::value > >
971  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(array<_Up, _Np> const& __array)
972      _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value)) {
973    std::__memberwise_copy_assign(*this, __array, typename __make_tuple_indices<sizeof...(_Tp)>::type());
974    return *this;
975  }
976
977  // EXTENSION
978  template <class _Up,
979            size_t _Np,
980            class = void,
981            class = __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up>... >::value > >
982  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(array<_Up, _Np>&& __array)
983      _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value)) {
984    std::__memberwise_forward_assign(
985        *this,
986        std::move(__array),
987        __tuple_types<_If<true, _Up, _Tp>...>(),
988        typename __make_tuple_indices<sizeof...(_Tp)>::type());
989    return *this;
990  }
991
992  // [tuple.swap]
993  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple& __t)
994      _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
995    __base_.swap(__t.__base_);
996  }
997
998#  if _LIBCPP_STD_VER >= 23
999  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple& __t) const
1000      noexcept(__all<is_nothrow_swappable_v<const _Tp&>...>::value) {
1001    __base_.swap(__t.__base_);
1002  }
1003#  endif // _LIBCPP_STD_VER >= 23
1004};
1005
1006template <>
1007class _LIBCPP_TEMPLATE_VIS tuple<> {
1008public:
1009  constexpr tuple() _NOEXCEPT = default;
1010  template <class _Alloc>
1011  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1012  template <class _Alloc>
1013  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1014  template <class _Up>
1015  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(array<_Up, 0>) _NOEXCEPT {}
1016  template <class _Alloc, class _Up>
1017  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1018  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple&) _NOEXCEPT {}
1019#  if _LIBCPP_STD_VER >= 23
1020  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple&) const noexcept {}
1021#  endif
1022};
1023
1024#  if _LIBCPP_STD_VER >= 23
1025template <class... _TTypes, class... _UTypes, template <class> class _TQual, template <class> class _UQual>
1026  requires requires { typename tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>; }
1027struct basic_common_reference<tuple<_TTypes...>, tuple<_UTypes...>, _TQual, _UQual> {
1028  using type = tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>;
1029};
1030
1031template <class... _TTypes, class... _UTypes>
1032  requires requires { typename tuple<common_type_t<_TTypes, _UTypes>...>; }
1033struct common_type<tuple<_TTypes...>, tuple<_UTypes...>> {
1034  using type = tuple<common_type_t<_TTypes, _UTypes>...>;
1035};
1036#  endif // _LIBCPP_STD_VER >= 23
1037
1038#  if _LIBCPP_STD_VER >= 17
1039template <class... _Tp>
1040tuple(_Tp...) -> tuple<_Tp...>;
1041template <class _Tp1, class _Tp2>
1042tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1043template <class _Alloc, class... _Tp>
1044tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1045template <class _Alloc, class _Tp1, class _Tp2>
1046tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1047template <class _Alloc, class... _Tp>
1048tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1049#  endif
1050
1051template <class... _Tp, __enable_if_t<__all<__is_swappable<_Tp>::value...>::value, int> = 0>
1052inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1053    _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
1054  __t.swap(__u);
1055}
1056
1057#  if _LIBCPP_STD_VER >= 23
1058template <class... _Tp>
1059_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<__all<is_swappable_v<const _Tp>...>::value, void>
1060swap(const tuple<_Tp...>& __lhs,
1061     const tuple<_Tp...>& __rhs) noexcept(__all<is_nothrow_swappable_v<const _Tp>...>::value) {
1062  __lhs.swap(__rhs);
1063}
1064#  endif
1065
1066// get
1067
1068template <size_t _Ip, class... _Tp>
1069inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&
1070get(tuple<_Tp...>& __t) _NOEXCEPT {
1071  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1072  return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1073}
1074
1075template <size_t _Ip, class... _Tp>
1076inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1077get(const tuple<_Tp...>& __t) _NOEXCEPT {
1078  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1079  return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1080}
1081
1082template <size_t _Ip, class... _Tp>
1083inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1084get(tuple<_Tp...>&& __t) _NOEXCEPT {
1085  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1086  return static_cast<type&&>(static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1087}
1088
1089template <size_t _Ip, class... _Tp>
1090inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1091get(const tuple<_Tp...>&& __t) _NOEXCEPT {
1092  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1093  return static_cast<const type&&>(static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1094}
1095
1096#  if _LIBCPP_STD_VER >= 14
1097
1098namespace __find_detail {
1099
1100static constexpr size_t __not_found = static_cast<size_t>(-1);
1101static constexpr size_t __ambiguous = __not_found - 1;
1102
1103inline _LIBCPP_HIDE_FROM_ABI constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
1104  return !__matches ? __res : (__res == __not_found ? __curr_i : __ambiguous);
1105}
1106
1107template <size_t _Nx>
1108inline _LIBCPP_HIDE_FROM_ABI constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1109  return __i == _Nx
1110           ? __not_found
1111           : __find_detail::__find_idx_return(__i, __find_detail::__find_idx(__i + 1, __matches), __matches[__i]);
1112}
1113
1114template <class _T1, class... _Args>
1115struct __find_exactly_one_checked {
1116  static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1117  static constexpr size_t value                     = __find_detail::__find_idx(0, __matches);
1118  static_assert(value != __not_found, "type not found in type list");
1119  static_assert(value != __ambiguous, "type occurs more than once in type list");
1120};
1121
1122template <class _T1>
1123struct __find_exactly_one_checked<_T1> {
1124  static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1125};
1126
1127} // namespace __find_detail
1128
1129template <typename _T1, typename... _Args>
1130struct __find_exactly_one_t : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {};
1131
1132template <class _T1, class... _Args>
1133inline _LIBCPP_HIDE_FROM_ABI constexpr _T1& get(tuple<_Args...>& __tup) noexcept {
1134  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1135}
1136
1137template <class _T1, class... _Args>
1138inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept {
1139  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1140}
1141
1142template <class _T1, class... _Args>
1143inline _LIBCPP_HIDE_FROM_ABI constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept {
1144  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1145}
1146
1147template <class _T1, class... _Args>
1148inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept {
1149  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1150}
1151
1152#  endif
1153
1154// tie
1155
1156template <class... _Tp>
1157inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&...> tie(_Tp&... __t) _NOEXCEPT {
1158  return tuple<_Tp&...>(__t...);
1159}
1160
1161template <class _Up>
1162struct __ignore_t {
1163  template <class _Tp>
1164  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const __ignore_t& operator=(_Tp&&) const {
1165    return *this;
1166  }
1167};
1168
1169#  if _LIBCPP_STD_VER >= 17
1170inline constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1171#  else
1172namespace {
1173constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1174} // namespace
1175#  endif
1176
1177template <class... _Tp>
1178inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<typename __unwrap_ref_decay<_Tp>::type...>
1179make_tuple(_Tp&&... __t) {
1180  return tuple<typename __unwrap_ref_decay<_Tp>::type...>(std::forward<_Tp>(__t)...);
1181}
1182
1183template <class... _Tp>
1184inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&&...> forward_as_tuple(_Tp&&... __t) _NOEXCEPT {
1185  return tuple<_Tp&&...>(std::forward<_Tp>(__t)...);
1186}
1187
1188template <size_t _Ip>
1189struct __tuple_equal {
1190  template <class _Tp, class _Up>
1191  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1192    return __tuple_equal<_Ip - 1>()(__x, __y) && std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y);
1193  }
1194};
1195
1196template <>
1197struct __tuple_equal<0> {
1198  template <class _Tp, class _Up>
1199  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1200    return true;
1201  }
1202};
1203
1204template <class... _Tp, class... _Up>
1205inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1206operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1207  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1208  return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1209}
1210
1211#  if _LIBCPP_STD_VER >= 20
1212
1213// operator<=>
1214
1215template <class... _Tp, class... _Up, size_t... _Is>
1216_LIBCPP_HIDE_FROM_ABI constexpr auto
1217__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
1218  common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
1219  static_cast<void>(
1220      ((__result = std::__synth_three_way(std::get<_Is>(__x), std::get<_Is>(__y)), __result != 0) || ...));
1221  return __result;
1222}
1223
1224template <class... _Tp, class... _Up>
1225  requires(sizeof...(_Tp) == sizeof...(_Up))
1226_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
1227operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1228  return std::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
1229}
1230
1231#  else // _LIBCPP_STD_VER >= 20
1232
1233template <class... _Tp, class... _Up>
1234inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1235operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1236  return !(__x == __y);
1237}
1238
1239template <size_t _Ip>
1240struct __tuple_less {
1241  template <class _Tp, class _Up>
1242  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1243    const size_t __idx = tuple_size<_Tp>::value - _Ip;
1244    if (std::get<__idx>(__x) < std::get<__idx>(__y))
1245      return true;
1246    if (std::get<__idx>(__y) < std::get<__idx>(__x))
1247      return false;
1248    return __tuple_less<_Ip - 1>()(__x, __y);
1249  }
1250};
1251
1252template <>
1253struct __tuple_less<0> {
1254  template <class _Tp, class _Up>
1255  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1256    return false;
1257  }
1258};
1259
1260template <class... _Tp, class... _Up>
1261inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1262operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1263  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1264  return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1265}
1266
1267template <class... _Tp, class... _Up>
1268inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1269operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1270  return __y < __x;
1271}
1272
1273template <class... _Tp, class... _Up>
1274inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1275operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1276  return !(__x < __y);
1277}
1278
1279template <class... _Tp, class... _Up>
1280inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1281operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1282  return !(__y < __x);
1283}
1284
1285#  endif // _LIBCPP_STD_VER >= 20
1286
1287// tuple_cat
1288
1289template <class _Tp, class _Up>
1290struct __tuple_cat_type;
1291
1292template <class... _Ttypes, class... _Utypes>
1293struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> > {
1294  typedef _LIBCPP_NODEBUG tuple<_Ttypes..., _Utypes...> type;
1295};
1296
1297template <class _ResultTuple, bool _Is_Tuple0TupleLike, class... _Tuples>
1298struct __tuple_cat_return_1 {};
1299
1300template <class... _Types, class _Tuple0>
1301struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0> {
1302  using type _LIBCPP_NODEBUG =
1303      typename __tuple_cat_type< tuple<_Types...>,
1304                                 typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type;
1305};
1306
1307template <class... _Types, class _Tuple0, class _Tuple1, class... _Tuples>
1308struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1309    : public __tuple_cat_return_1<
1310          typename __tuple_cat_type< tuple<_Types...>,
1311                                     typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type,
1312          __tuple_like_ext<__libcpp_remove_reference_t<_Tuple1> >::value,
1313          _Tuple1,
1314          _Tuples...> {};
1315
1316template <class... _Tuples>
1317struct __tuple_cat_return;
1318
1319template <class _Tuple0, class... _Tuples>
1320struct __tuple_cat_return<_Tuple0, _Tuples...>
1321    : public __tuple_cat_return_1<tuple<>,
1322                                  __tuple_like_ext<__libcpp_remove_reference_t<_Tuple0> >::value,
1323                                  _Tuple0,
1324                                  _Tuples...> {};
1325
1326template <>
1327struct __tuple_cat_return<> {
1328  typedef _LIBCPP_NODEBUG tuple<> type;
1329};
1330
1331inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<> tuple_cat() { return tuple<>(); }
1332
1333template <class _Rp, class _Indices, class _Tuple0, class... _Tuples>
1334struct __tuple_cat_return_ref_imp;
1335
1336template <class... _Types, size_t... _I0, class _Tuple0>
1337struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0> {
1338  typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1339  typedef tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_I0, _T0>::type>&&...> type;
1340};
1341
1342template <class... _Types, size_t... _I0, class _Tuple0, class _Tuple1, class... _Tuples>
1343struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0, _Tuple1, _Tuples...>
1344    : public __tuple_cat_return_ref_imp<
1345          tuple<_Types...,
1346                __apply_cv_t<_Tuple0, typename tuple_element<_I0, __libcpp_remove_reference_t<_Tuple0>>::type>&&...>,
1347          typename __make_tuple_indices<tuple_size<__libcpp_remove_reference_t<_Tuple1> >::value>::type,
1348          _Tuple1,
1349          _Tuples...> {};
1350
1351template <class _Tuple0, class... _Tuples>
1352struct __tuple_cat_return_ref
1353    : public __tuple_cat_return_ref_imp<
1354          tuple<>,
1355          typename __make_tuple_indices< tuple_size<__libcpp_remove_reference_t<_Tuple0> >::value >::type,
1356          _Tuple0,
1357          _Tuples...> {};
1358
1359template <class _Types, class _I0, class _J0>
1360struct __tuple_cat;
1361
1362template <class... _Types, size_t... _I0, size_t... _J0>
1363struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> > {
1364  template <class _Tuple0>
1365  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1366      typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1367      operator()(tuple<_Types...> __t, _Tuple0&& __t0) {
1368    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1369    return std::forward_as_tuple(
1370        std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...);
1371  }
1372
1373  template <class _Tuple0, class _Tuple1, class... _Tuples>
1374  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1375      typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1376      operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&&... __tpls) {
1377    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1378    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1379    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple1> _T1;
1380    return __tuple_cat<tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_J0, _T0>::type>&&...>,
1381                       typename __make_tuple_indices<sizeof...(_Types) + tuple_size<_T0>::value>::type,
1382                       typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1383        std::forward_as_tuple(
1384            std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...),
1385        std::forward<_Tuple1>(__t1),
1386        std::forward<_Tuples>(__tpls)...);
1387  }
1388};
1389
1390template <class _Tuple0, class... _Tuples>
1391inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1392tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls) {
1393  typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1394  return __tuple_cat<tuple<>, __tuple_indices<>, typename __make_tuple_indices<tuple_size<_T0>::value>::type>()(
1395      tuple<>(), std::forward<_Tuple0>(__t0), std::forward<_Tuples>(__tpls)...);
1396}
1397
1398template <class... _Tp, class _Alloc>
1399struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc> : true_type {};
1400
1401template <class _T1, class _T2>
1402template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
1403inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_T1, _T2>::pair(
1404    piecewise_construct_t,
1405    tuple<_Args1...>& __first_args,
1406    tuple<_Args2...>& __second_args,
1407    __tuple_indices<_I1...>,
1408    __tuple_indices<_I2...>)
1409    : first(std::forward<_Args1>(std::get<_I1>(__first_args))...),
1410      second(std::forward<_Args2>(std::get<_I2>(__second_args))...) {}
1411
1412#  if _LIBCPP_STD_VER >= 17
1413template <class _Tp>
1414inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1415
1416#    define _LIBCPP_NOEXCEPT_RETURN(...)                                                                               \
1417      noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1418
1419// The _LIBCPP_NOEXCEPT_RETURN macro breaks formatting.
1420// clang-format off
1421template <class _Fn, class _Tuple, size_t... _Id>
1422inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto)
1423__apply_tuple_impl(_Fn&& __f, _Tuple&& __t, __tuple_indices<_Id...>)
1424    _LIBCPP_NOEXCEPT_RETURN(std::__invoke(std::forward<_Fn>(__f), std::get<_Id>(std::forward<_Tuple>(__t))...))
1425
1426template <class _Fn, class _Tuple>
1427inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) apply(_Fn&& __f, _Tuple&& __t)
1428    _LIBCPP_NOEXCEPT_RETURN(std::__apply_tuple_impl(
1429        std::forward<_Fn>(__f),
1430        std::forward<_Tuple>(__t),
1431        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1432
1433template <class _Tp, class _Tuple, size_t... _Idx>
1434inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1435    _LIBCPP_NOEXCEPT_RETURN(_Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...))
1436
1437template <class _Tp, class _Tuple>
1438inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp make_from_tuple(_Tuple&& __t)
1439    _LIBCPP_NOEXCEPT_RETURN(std::__make_from_tuple_impl<_Tp>(
1440        std::forward<_Tuple>(__t), typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1441
1442#    undef _LIBCPP_NOEXCEPT_RETURN
1443
1444#  endif // _LIBCPP_STD_VER >= 17
1445
1446#endif // !defined(_LIBCPP_CXX03_LANG)
1447
1448_LIBCPP_END_NAMESPACE_STD
1449
1450_LIBCPP_POP_MACROS
1451
1452// clang-format on
1453
1454#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1455#  include <exception>
1456#  include <iosfwd>
1457#  include <new>
1458#  include <type_traits>
1459#  include <typeinfo>
1460#  include <utility>
1461#endif
1462
1463#endif // _LIBCPP_TUPLE
1464