xref: /llvm-project/libcxx/include/tuple (revision cac67d39362b23466708e464c00ce84abe16bece)
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
135struct ignore-type { // exposition only                             // Since C++26
136  constexpr const ignore-type&
137    operator=(const auto &) const noexcept
138      { return *this; }
139};
140inline constexpr ignore-type ignore;
141
142template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
143template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
144template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
145template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
146
147// [tuple.apply], calling a function with a tuple of arguments:
148template <class F, class Tuple>
149  constexpr decltype(auto) apply(F&& f, Tuple&& t) noexcept(see below);  // C++17 noexcept since C++23
150template <class T, class Tuple>
151  constexpr T make_from_tuple(Tuple&& t); // C++17
152
153// 20.4.1.4, tuple helper classes:
154template <class T> struct tuple_size; // undefined
155template <class... T> struct tuple_size<tuple<T...>>;
156template <class T>
157 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
158template <size_t I, class T> struct tuple_element; // undefined
159template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
160template <size_t I, class T>
161  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
162
163// 20.4.1.5, element access:
164template <size_t I, class... T>
165    typename tuple_element<I, tuple<T...>>::type&
166    get(tuple<T...>&) noexcept; // constexpr in C++14
167template <size_t I, class... T>
168    const typename tuple_element<I, tuple<T...>>::type&
169    get(const tuple<T...>&) noexcept; // constexpr in C++14
170template <size_t I, class... T>
171    typename tuple_element<I, tuple<T...>>::type&&
172    get(tuple<T...>&&) noexcept; // constexpr in C++14
173template <size_t I, class... T>
174    const typename tuple_element<I, tuple<T...>>::type&&
175    get(const tuple<T...>&&) noexcept; // constexpr in C++14
176
177template <class T1, class... T>
178    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
179template <class T1, class... T>
180    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
181template <class T1, class... T>
182    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
183template <class T1, class... T>
184    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
185
186// 20.4.1.6, relational operators:
187template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
188template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
189template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
190template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
191template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
192template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
193template<class... T, class... U>
194  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
195    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
196
197template <class... Types, class Alloc>
198  struct uses_allocator<tuple<Types...>, Alloc>;
199
200template <class... Types>
201  void
202  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
203
204template <class... Types>
205  constexpr void swap(const tuple<Types...>& x, const tuple<Types...>& y) noexcept(see-below);   // C++23
206
207}  // std
208
209*/
210
211// clang-format on
212
213#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
214#  include <__cxx03/tuple>
215#else
216#  include <__compare/common_comparison_category.h>
217#  include <__compare/ordering.h>
218#  include <__compare/synth_three_way.h>
219#  include <__config>
220#  include <__cstddef/size_t.h>
221#  include <__fwd/array.h>
222#  include <__fwd/pair.h>
223#  include <__fwd/tuple.h>
224#  include <__memory/allocator_arg_t.h>
225#  include <__memory/uses_allocator.h>
226#  include <__tuple/find_index.h>
227#  include <__tuple/ignore.h>
228#  include <__tuple/make_tuple_types.h>
229#  include <__tuple/sfinae_helpers.h>
230#  include <__tuple/tuple_element.h>
231#  include <__tuple/tuple_indices.h>
232#  include <__tuple/tuple_like_ext.h>
233#  include <__tuple/tuple_size.h>
234#  include <__tuple/tuple_types.h>
235#  include <__type_traits/common_reference.h>
236#  include <__type_traits/common_type.h>
237#  include <__type_traits/conditional.h>
238#  include <__type_traits/conjunction.h>
239#  include <__type_traits/copy_cvref.h>
240#  include <__type_traits/disjunction.h>
241#  include <__type_traits/enable_if.h>
242#  include <__type_traits/invoke.h>
243#  include <__type_traits/is_arithmetic.h>
244#  include <__type_traits/is_assignable.h>
245#  include <__type_traits/is_constructible.h>
246#  include <__type_traits/is_convertible.h>
247#  include <__type_traits/is_empty.h>
248#  include <__type_traits/is_final.h>
249#  include <__type_traits/is_implicitly_default_constructible.h>
250#  include <__type_traits/is_nothrow_assignable.h>
251#  include <__type_traits/is_nothrow_constructible.h>
252#  include <__type_traits/is_reference.h>
253#  include <__type_traits/is_same.h>
254#  include <__type_traits/is_swappable.h>
255#  include <__type_traits/is_trivially_relocatable.h>
256#  include <__type_traits/lazy.h>
257#  include <__type_traits/maybe_const.h>
258#  include <__type_traits/nat.h>
259#  include <__type_traits/negation.h>
260#  include <__type_traits/remove_cv.h>
261#  include <__type_traits/remove_cvref.h>
262#  include <__type_traits/remove_reference.h>
263#  include <__type_traits/unwrap_ref.h>
264#  include <__utility/declval.h>
265#  include <__utility/forward.h>
266#  include <__utility/integer_sequence.h>
267#  include <__utility/move.h>
268#  include <__utility/piecewise_construct.h>
269#  include <__utility/swap.h>
270#  include <version>
271
272// standard-mandated includes
273
274// [tuple.syn]
275#  include <compare>
276
277#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
278#    pragma GCC system_header
279#  endif
280
281_LIBCPP_PUSH_MACROS
282#  include <__undef_macros>
283
284_LIBCPP_BEGIN_NAMESPACE_STD
285
286#  ifndef _LIBCPP_CXX03_LANG
287
288// __tuple_leaf
289
290template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value >
291class __tuple_leaf;
292
293template <size_t _Ip, class _Hp, bool _Ep>
294inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
295swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y) noexcept(__is_nothrow_swappable_v<_Hp>) {
296  swap(__x.get(), __y.get());
297}
298
299template <size_t _Ip, class _Hp, bool _Ep>
300_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
301swap(const __tuple_leaf<_Ip, _Hp, _Ep>& __x,
302     const __tuple_leaf<_Ip, _Hp, _Ep>& __y) noexcept(__is_nothrow_swappable_v<const _Hp>) {
303  swap(__x.get(), __y.get());
304}
305
306template <size_t _Ip, class _Hp, bool>
307class __tuple_leaf {
308  _Hp __value_;
309
310  template <class _Tp>
311  static _LIBCPP_HIDE_FROM_ABI constexpr bool __can_bind_reference() {
312#    if __has_keyword(__reference_binds_to_temporary)
313    return !__reference_binds_to_temporary(_Hp, _Tp);
314#    else
315    return true;
316#    endif
317  }
318
319public:
320  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&) = delete;
321
322  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() noexcept(is_nothrow_default_constructible<_Hp>::value) : __value_() {
323    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
324  }
325
326  template <class _Alloc>
327  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) : __value_() {
328    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
329  }
330
331  template <class _Alloc>
332  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
333      : __value_(allocator_arg_t(), __a) {
334    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
335  }
336
337  template <class _Alloc>
338  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : __value_(__a) {
339    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
340  }
341
342  template <
343      class _Tp,
344      __enable_if_t<_And<_IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value, int> = 0>
345  _LIBCPP_HIDE_FROM_ABI
346  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t) noexcept(is_nothrow_constructible<_Hp, _Tp>::value)
347      : __value_(std::forward<_Tp>(__t)) {
348    static_assert(__can_bind_reference<_Tp&&>(),
349                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
350  }
351
352  template <class _Tp, class _Alloc>
353  _LIBCPP_HIDE_FROM_ABI
354  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
355      : __value_(std::forward<_Tp>(__t)) {
356    static_assert(__can_bind_reference<_Tp&&>(),
357                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
358  }
359
360  template <class _Tp, class _Alloc>
361  _LIBCPP_HIDE_FROM_ABI
362  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
363      : __value_(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {
364    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
365  }
366
367  template <class _Tp, class _Alloc>
368  _LIBCPP_HIDE_FROM_ABI
369  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
370      : __value_(std::forward<_Tp>(__t), __a) {
371    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
372  }
373
374  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(const __tuple_leaf& __t) = default;
375  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(__tuple_leaf&& __t)      = default;
376
377  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int
378  swap(__tuple_leaf& __t) noexcept(__is_nothrow_swappable_v<__tuple_leaf>) {
379    std::swap(*this, __t);
380    return 0;
381  }
382
383  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __t) const
384      noexcept(__is_nothrow_swappable_v<const __tuple_leaf>) {
385    std::swap(*this, __t);
386    return 0;
387  }
388
389  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return __value_; }
390  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT { return __value_; }
391};
392
393template <size_t _Ip, class _Hp>
394class __tuple_leaf<_Ip, _Hp, true> : private __remove_cv_t<_Hp> {
395public:
396  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&) = delete;
397
398  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() noexcept(is_nothrow_default_constructible<_Hp>::value) {}
399
400  template <class _Alloc>
401  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
402
403  template <class _Alloc>
404  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
405      : _Hp(allocator_arg_t(), __a) {}
406
407  template <class _Alloc>
408  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : _Hp(__a) {}
409
410  template <class _Tp,
411            __enable_if_t< _And< _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value,
412                           int> = 0>
413  _LIBCPP_HIDE_FROM_ABI
414  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t) noexcept(is_nothrow_constructible<_Hp, _Tp>::value)
415      : _Hp(std::forward<_Tp>(__t)) {}
416
417  template <class _Tp, class _Alloc>
418  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
419      : _Hp(std::forward<_Tp>(__t)) {}
420
421  template <class _Tp, class _Alloc>
422  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
423      : _Hp(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {}
424
425  template <class _Tp, class _Alloc>
426  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
427      : _Hp(std::forward<_Tp>(__t), __a) {}
428
429  __tuple_leaf(__tuple_leaf const&) = default;
430  __tuple_leaf(__tuple_leaf&&)      = default;
431
432  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int
433  swap(__tuple_leaf& __t) noexcept(__is_nothrow_swappable_v<__tuple_leaf>) {
434    std::swap(*this, __t);
435    return 0;
436  }
437
438  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __rhs) const
439      noexcept(__is_nothrow_swappable_v<const __tuple_leaf>) {
440    std::swap(*this, __rhs);
441    return 0;
442  }
443
444  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return static_cast<_Hp&>(*this); }
445  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT {
446    return static_cast<const _Hp&>(*this);
447  }
448};
449
450template <class... _Tp>
451_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void __swallow(_Tp&&...) _NOEXCEPT {}
452
453template <class _Tp>
454struct __all_default_constructible;
455
456template <class... _Tp>
457struct __all_default_constructible<__tuple_types<_Tp...>> : __all<is_default_constructible<_Tp>::value...> {};
458
459// __tuple_impl
460
461template <class _Indx, class... _Tp>
462struct __tuple_impl;
463
464template <size_t... _Indx, class... _Tp>
465struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
466    : public __tuple_leaf<_Indx, _Tp>... {
467  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_impl() noexcept(
468      __all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
469
470  template <size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
471  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
472      __tuple_indices<_Uf...>,
473      __tuple_types<_Tf...>,
474      __tuple_indices<_Ul...>,
475      __tuple_types<_Tl...>,
476      _Up&&... __u) noexcept(__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
477                             __all<is_nothrow_default_constructible<_Tl>::value...>::value)
478      : __tuple_leaf<_Uf, _Tf>(std::forward<_Up>(__u))..., __tuple_leaf<_Ul, _Tl>()... {}
479
480  template <class _Alloc, size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
481  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
482      allocator_arg_t,
483      const _Alloc& __a,
484      __tuple_indices<_Uf...>,
485      __tuple_types<_Tf...>,
486      __tuple_indices<_Ul...>,
487      __tuple_types<_Tl...>,
488      _Up&&... __u)
489      : __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a, std::forward<_Up>(__u))...,
490        __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)... {}
491
492  template <class _Tuple, __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value, int> = 0>
493  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(_Tuple&& __t) noexcept(
494      (__all<is_nothrow_constructible<
495           _Tp,
496           typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
497      : __tuple_leaf<_Indx, _Tp>(
498            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
499                std::get<_Indx>(__t)))... {}
500
501  template <class _Alloc, class _Tuple, __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value, int> = 0>
502  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
503      : __tuple_leaf<_Indx, _Tp>(
504            __uses_alloc_ctor<_Tp,
505                              _Alloc,
506                              typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(),
507            __a,
508            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
509                std::get<_Indx>(__t)))... {}
510
511  __tuple_impl(const __tuple_impl&) = default;
512  __tuple_impl(__tuple_impl&&)      = default;
513
514  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
515  swap(__tuple_impl& __t) noexcept(__all<__is_nothrow_swappable_v<_Tp>...>::value) {
516    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
517  }
518
519  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(const __tuple_impl& __t) const
520      noexcept(__all<__is_nothrow_swappable_v<const _Tp>...>::value) {
521    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t))...);
522  }
523};
524
525template <class _Dest, class _Source, size_t... _Np>
526_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
527__memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
528  std::__swallow(((std::get<_Np>(__dest) = std::get<_Np>(__source)), void(), 0)...);
529}
530
531template <class _Dest, class _Source, class... _Up, size_t... _Np>
532_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
533__memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
534  std::__swallow(((std::get<_Np>(__dest) = std::forward<_Up>(std::get<_Np>(__source))), void(), 0)...);
535}
536
537template <class... _Tp>
538class _LIBCPP_TEMPLATE_VIS tuple {
539  typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
540
541  _BaseT __base_;
542
543  template <size_t _Jp, class... _Up>
544  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
545  template <size_t _Jp, class... _Up>
546  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&
547  get(const tuple<_Up...>&) _NOEXCEPT;
548  template <size_t _Jp, class... _Up>
549  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type&&
550  get(tuple<_Up...>&&) _NOEXCEPT;
551  template <size_t _Jp, class... _Up>
552  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&&
553  get(const tuple<_Up...>&&) _NOEXCEPT;
554
555public:
556  using __trivially_relocatable _LIBCPP_NODEBUG =
557      __conditional_t<_And<__libcpp_is_trivially_relocatable<_Tp>...>::value, tuple, void>;
558
559  // [tuple.cnstr]
560
561  // tuple() constructors (including allocator_arg_t variants)
562  template <template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
563            template <class...> class _IsDefault                   = is_default_constructible,
564            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
565  _LIBCPP_HIDE_FROM_ABI constexpr explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value)
566      tuple() noexcept(_And<is_nothrow_default_constructible<_Tp>...>::value) {}
567
568  template <class _Alloc,
569            template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
570            template <class...> class _IsDefault                   = is_default_constructible,
571            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
572  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value)
573      tuple(allocator_arg_t, _Alloc const& __a)
574      : __base_(allocator_arg_t(),
575                __a,
576                __tuple_indices<>(),
577                __tuple_types<>(),
578                typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
579                __tuple_types<_Tp...>()) {}
580
581  // tuple(const T&...) constructors (including allocator_arg_t variants)
582  template <template <class...> class _And = _And,
583            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
584  _LIBCPP_HIDE_FROM_ABI
585  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value)
586      tuple(const _Tp&... __t) noexcept(_And<is_nothrow_copy_constructible<_Tp>...>::value)
587      : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
588                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
589                typename __make_tuple_indices<0>::type(),
590                typename __make_tuple_types<tuple, 0>::type(),
591                __t...) {}
592
593  template <class _Alloc,
594            template <class...> class _And = _And,
595            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
596  _LIBCPP_HIDE_FROM_ABI
597  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value)
598      tuple(allocator_arg_t, const _Alloc& __a, const _Tp&... __t)
599      : __base_(allocator_arg_t(),
600                __a,
601                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
602                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
603                typename __make_tuple_indices<0>::type(),
604                typename __make_tuple_types<tuple, 0>::type(),
605                __t...) {}
606
607  // tuple(U&& ...) constructors (including allocator_arg_t variants)
608  template <class... _Up>
609  struct _IsThisTuple : false_type {};
610  template <class _Up>
611  struct _IsThisTuple<_Up> : is_same<__remove_cvref_t<_Up>, tuple> {};
612
613  template <class... _Up>
614  struct _EnableUTypesCtor
615      : _And< _BoolConstant<sizeof...(_Tp) >= 1>,
616              _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
617              is_constructible<_Tp, _Up>... > {};
618
619  template <class... _Up,
620            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
621                           int> = 0>
622  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
623      tuple(_Up&&... __u) noexcept(_And<is_nothrow_constructible<_Tp, _Up>...>::value)
624      : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
625                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
626                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
627                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
628                std::forward<_Up>(__u)...) {}
629
630  template <class _Alloc,
631            class... _Up,
632            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
633                           int> = 0>
634  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
635      tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
636      : __base_(allocator_arg_t(),
637                __a,
638                typename __make_tuple_indices<sizeof...(_Up)>::type(),
639                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
640                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
641                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
642                std::forward<_Up>(__u)...) {}
643
644  // Copy and move constructors (including the allocator_arg_t variants)
645  tuple(const tuple&) = default;
646  tuple(tuple&&)      = default;
647
648  template <class _Alloc,
649            template <class...> class _And                                  = _And,
650            __enable_if_t< _And<is_copy_constructible<_Tp>...>::value, int> = 0>
651  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
652      : __base_(allocator_arg_t(), __alloc, __t) {}
653
654  template <class _Alloc,
655            template <class...> class _And                                  = _And,
656            __enable_if_t< _And<is_move_constructible<_Tp>...>::value, int> = 0>
657  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
658      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
659
660  // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
661
662  template <class _OtherTuple, class _DecayedOtherTuple = __remove_cvref_t<_OtherTuple>, class = void>
663  struct _EnableCtorFromUTypesTuple : false_type {};
664
665  template <class _OtherTuple, class... _Up>
666  struct _EnableCtorFromUTypesTuple<
667      _OtherTuple,
668      tuple<_Up...>,
669      // the length of the packs needs to checked first otherwise the 2 packs cannot be expanded simultaneously below
670      __enable_if_t<sizeof...(_Up) == sizeof...(_Tp)>>
671      : _And<
672            // the two conditions below are not in spec. The purpose is to disable the UTypes Ctor when copy/move Ctor
673            // can work. Otherwise, is_constructible can trigger hard error in those cases
674            // https://godbolt.org/z/M94cGdKcE
675            _Not<is_same<_OtherTuple, const tuple&> >,
676            _Not<is_same<_OtherTuple, tuple&&> >,
677            is_constructible<_Tp, __copy_cvref_t<_OtherTuple, _Up> >...,
678            _Lazy<_Or,
679                  _BoolConstant<sizeof...(_Tp) != 1>,
680                  // _Tp and _Up are 1-element packs - the pack expansions look
681                  // weird to avoid tripping up the type traits in degenerate cases
682                  _Lazy<_And,
683                        _Not<is_same<_Tp, _Up> >...,
684                        _Not<is_convertible<_OtherTuple, _Tp> >...,
685                        _Not<is_constructible<_Tp, _OtherTuple> >... > > > {};
686
687  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
688  _LIBCPP_HIDE_FROM_ABI
689  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value)
690      tuple(const tuple<_Up...>& __t) noexcept(_And<is_nothrow_constructible<_Tp, const _Up&>...>::value)
691      : __base_(__t) {}
692
693  template <class... _Up,
694            class _Alloc,
695            __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
696  _LIBCPP_HIDE_FROM_ABI
697  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value)
698      tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
699      : __base_(allocator_arg_t(), __a, __t) {}
700
701#    if _LIBCPP_STD_VER >= 23
702  // tuple(tuple<U...>&) constructors (including allocator_arg_t variants)
703
704  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
705  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value) tuple(tuple<_Up...>& __t)
706      : __base_(__t) {}
707
708  template <class _Alloc, class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
709  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value)
710      tuple(allocator_arg_t, const _Alloc& __alloc, tuple<_Up...>& __t)
711      : __base_(allocator_arg_t(), __alloc, __t) {}
712#    endif // _LIBCPP_STD_VER >= 23
713
714  // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
715  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
716  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
717      tuple(tuple<_Up...>&& __t) noexcept(_And<is_nothrow_constructible<_Tp, _Up>...>::value)
718      : __base_(std::move(__t)) {}
719
720  template <class _Alloc,
721            class... _Up,
722            __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
723  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
724      tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
725      : __base_(allocator_arg_t(), __a, std::move(__t)) {}
726
727#    if _LIBCPP_STD_VER >= 23
728  // tuple(const tuple<U...>&&) constructors (including allocator_arg_t variants)
729
730  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
731  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
732      tuple(const tuple<_Up...>&& __t)
733      : __base_(std::move(__t)) {}
734
735  template <class _Alloc,
736            class... _Up,
737            enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
738  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
739      tuple(allocator_arg_t, const _Alloc& __alloc, const tuple<_Up...>&& __t)
740      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
741#    endif // _LIBCPP_STD_VER >= 23
742
743  // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
744
745  template <template <class...> class _Pred,
746            class _Pair,
747            class _DecayedPair = __remove_cvref_t<_Pair>,
748            class _Tuple       = tuple>
749  struct _CtorPredicateFromPair : false_type {};
750
751  template <template <class...> class _Pred, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
752  struct _CtorPredicateFromPair<_Pred, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
753      : _And< _Pred<_Tp1, __copy_cvref_t<_Pair, _Up1> >, _Pred<_Tp2, __copy_cvref_t<_Pair, _Up2> > > {};
754
755  template <class _Pair>
756  struct _EnableCtorFromPair : _CtorPredicateFromPair<is_constructible, _Pair> {};
757
758  template <class _Pair>
759  struct _NothrowConstructibleFromPair : _CtorPredicateFromPair<is_nothrow_constructible, _Pair> {};
760
761  template <class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
762  struct _BothImplicitlyConvertible : false_type {};
763
764  template <class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
765  struct _BothImplicitlyConvertible<_Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
766      : _And< is_convertible<__copy_cvref_t<_Pair, _Up1>, _Tp1>, is_convertible<__copy_cvref_t<_Pair, _Up2>, _Tp2> > {};
767
768  template <class _Up1,
769            class _Up2,
770            template <class...> class _And                                                   = _And,
771            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
772  _LIBCPP_HIDE_FROM_ABI
773  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value)
774      tuple(const pair<_Up1, _Up2>& __p) noexcept(_NothrowConstructibleFromPair<const pair<_Up1, _Up2>&>::value)
775      : __base_(__p) {}
776
777  template <class _Alloc,
778            class _Up1,
779            class _Up2,
780            template <class...> class _And                                                   = _And,
781            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
782  _LIBCPP_HIDE_FROM_ABI
783  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value)
784      tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
785      : __base_(allocator_arg_t(), __a, __p) {}
786
787#    if _LIBCPP_STD_VER >= 23
788  // tuple(pair<U1, U2>&) constructors (including allocator_arg_t variants)
789
790  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<pair<_U1, _U2>&>::value>* = nullptr>
791  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
792      tuple(pair<_U1, _U2>& __p)
793      : __base_(__p) {}
794
795  template <class _Alloc,
796            class _U1,
797            class _U2,
798            enable_if_t< _EnableCtorFromPair<std::pair<_U1, _U2>&>::value>* = nullptr>
799  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
800      tuple(allocator_arg_t, const _Alloc& __alloc, pair<_U1, _U2>& __p)
801      : __base_(allocator_arg_t(), __alloc, __p) {}
802#    endif
803
804  // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
805
806  template <class _Up1,
807            class _Up2,
808            template <class...> class _And                                              = _And,
809            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
810  _LIBCPP_HIDE_FROM_ABI
811  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value)
812      tuple(pair<_Up1, _Up2>&& __p) noexcept(_NothrowConstructibleFromPair<pair<_Up1, _Up2>&&>::value)
813      : __base_(std::move(__p)) {}
814
815  template <class _Alloc,
816            class _Up1,
817            class _Up2,
818            template <class...> class _And                                              = _And,
819            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
820  _LIBCPP_HIDE_FROM_ABI
821  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value)
822      tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
823      : __base_(allocator_arg_t(), __a, std::move(__p)) {}
824
825#    if _LIBCPP_STD_VER >= 23
826  // tuple(const pair<U1, U2>&&) constructors (including allocator_arg_t variants)
827
828  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
829  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
830      tuple(const pair<_U1, _U2>&& __p)
831      : __base_(std::move(__p)) {}
832
833  template <class _Alloc,
834            class _U1,
835            class _U2,
836            enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
837  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
838      tuple(allocator_arg_t, const _Alloc& __alloc, const pair<_U1, _U2>&& __p)
839      : __base_(allocator_arg_t(), __alloc, std::move(__p)) {}
840#    endif // _LIBCPP_STD_VER >= 23
841
842  // [tuple.assign]
843  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
844  operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple) noexcept(
845      _And<is_nothrow_copy_assignable<_Tp>...>::value) {
846    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
847    return *this;
848  }
849
850#    if _LIBCPP_STD_VER >= 23
851  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple const& __tuple) const
852    requires(_And<is_copy_assignable<const _Tp>...>::value)
853  {
854    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
855    return *this;
856  }
857
858  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple&& __tuple) const
859    requires(_And<is_assignable<const _Tp&, _Tp>...>::value)
860  {
861    std::__memberwise_forward_assign(
862        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
863    return *this;
864  }
865#    endif // _LIBCPP_STD_VER >= 23
866
867  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
868  operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple) noexcept(
869      _And<is_nothrow_move_assignable<_Tp>...>::value) {
870    std::__memberwise_forward_assign(
871        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
872    return *this;
873  }
874
875  template <
876      class... _Up,
877      __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up const&>... >::value,
878                     int> = 0>
879  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
880  operator=(tuple<_Up...> const& __tuple) noexcept(_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value) {
881    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
882    return *this;
883  }
884
885  template <class... _Up,
886            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up>... >::value,
887                           int> = 0>
888  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
889  operator=(tuple<_Up...>&& __tuple) noexcept(_And<is_nothrow_assignable<_Tp&, _Up>...>::value) {
890    std::__memberwise_forward_assign(
891        *this, std::move(__tuple), __tuple_types<_Up...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
892    return *this;
893  }
894
895#    if _LIBCPP_STD_VER >= 23
896  template <class... _UTypes,
897            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
898                              is_assignable<const _Tp&, const _UTypes&>...>::value>* = nullptr>
899  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const tuple<_UTypes...>& __u) const {
900    std::__memberwise_copy_assign(*this, __u, typename __make_tuple_indices<sizeof...(_Tp)>::type());
901    return *this;
902  }
903
904  template <class... _UTypes,
905            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
906                              is_assignable<const _Tp&, _UTypes>...>::value>* = nullptr>
907  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple<_UTypes...>&& __u) const {
908    std::__memberwise_forward_assign(
909        *this, __u, __tuple_types<_UTypes...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
910    return *this;
911  }
912#    endif // _LIBCPP_STD_VER >= 23
913
914  template <template <class...> class _Pred,
915            bool _Const,
916            class _Pair,
917            class _DecayedPair = __remove_cvref_t<_Pair>,
918            class _Tuple       = tuple>
919  struct _AssignPredicateFromPair : false_type {};
920
921  template <template <class...> class _Pred, bool _Const, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
922  struct _AssignPredicateFromPair<_Pred, _Const, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
923      : _And<_Pred<__maybe_const<_Const, _Tp1>&, __copy_cvref_t<_Pair, _Up1> >,
924             _Pred<__maybe_const<_Const, _Tp2>&, __copy_cvref_t<_Pair, _Up2> > > {};
925
926  template <bool _Const, class _Pair>
927  struct _EnableAssignFromPair : _AssignPredicateFromPair<is_assignable, _Const, _Pair> {};
928
929  template <bool _Const, class _Pair>
930  struct _NothrowAssignFromPair : _AssignPredicateFromPair<is_nothrow_assignable, _Const, _Pair> {};
931
932#    if _LIBCPP_STD_VER >= 23
933  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, const pair<_U1, _U2>&>::value>* = nullptr>
934  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const pair<_U1, _U2>& __pair) const
935      noexcept(_NothrowAssignFromPair<true, const pair<_U1, _U2>&>::value) {
936    std::get<0>(*this) = __pair.first;
937    std::get<1>(*this) = __pair.second;
938    return *this;
939  }
940
941  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, pair<_U1, _U2>&&>::value>* = nullptr>
942  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(pair<_U1, _U2>&& __pair) const
943      noexcept(_NothrowAssignFromPair<true, pair<_U1, _U2>&&>::value) {
944    std::get<0>(*this) = std::move(__pair.first);
945    std::get<1>(*this) = std::move(__pair.second);
946    return *this;
947  }
948#    endif // _LIBCPP_STD_VER >= 23
949
950  template <class _Up1,
951            class _Up2,
952            __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2> const&>::value, int> = 0>
953  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
954  operator=(pair<_Up1, _Up2> const& __pair) noexcept(_NothrowAssignFromPair<false, pair<_Up1, _Up2> const&>::value) {
955    std::get<0>(*this) = __pair.first;
956    std::get<1>(*this) = __pair.second;
957    return *this;
958  }
959
960  template <class _Up1, class _Up2, __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2>&&>::value, int> = 0>
961  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
962  operator=(pair<_Up1, _Up2>&& __pair) noexcept(_NothrowAssignFromPair<false, pair<_Up1, _Up2>&&>::value) {
963    std::get<0>(*this) = std::forward<_Up1>(__pair.first);
964    std::get<1>(*this) = std::forward<_Up2>(__pair.second);
965    return *this;
966  }
967
968  // EXTENSION
969  template <
970      class _Up,
971      size_t _Np,
972      __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up const&>... >::value, int> = 0>
973  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
974  operator=(array<_Up, _Np> const& __array) noexcept(_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value) {
975    std::__memberwise_copy_assign(*this, __array, typename __make_tuple_indices<sizeof...(_Tp)>::type());
976    return *this;
977  }
978
979  // EXTENSION
980  template <class _Up,
981            size_t _Np,
982            class = void,
983            __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up>... >::value, int> = 0>
984  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
985  operator=(array<_Up, _Np>&& __array) noexcept(_And<is_nothrow_assignable<_Tp&, _Up>...>::value) {
986    std::__memberwise_forward_assign(
987        *this,
988        std::move(__array),
989        __tuple_types<_If<true, _Up, _Tp>...>(),
990        typename __make_tuple_indices<sizeof...(_Tp)>::type());
991    return *this;
992  }
993
994  // [tuple.swap]
995  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
996  swap(tuple& __t) noexcept(__all<__is_nothrow_swappable_v<_Tp>...>::value) {
997    __base_.swap(__t.__base_);
998  }
999
1000#    if _LIBCPP_STD_VER >= 23
1001  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple& __t) const
1002      noexcept(__all<is_nothrow_swappable_v<const _Tp&>...>::value) {
1003    __base_.swap(__t.__base_);
1004  }
1005#    endif // _LIBCPP_STD_VER >= 23
1006};
1007
1008template <>
1009class _LIBCPP_TEMPLATE_VIS tuple<> {
1010public:
1011  constexpr tuple() _NOEXCEPT = default;
1012  template <class _Alloc>
1013  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1014  template <class _Alloc>
1015  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1016  template <class _Up>
1017  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(array<_Up, 0>) _NOEXCEPT {}
1018  template <class _Alloc, class _Up>
1019  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1020  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple&) _NOEXCEPT {}
1021#    if _LIBCPP_STD_VER >= 23
1022  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple&) const noexcept {}
1023#    endif
1024};
1025
1026#    if _LIBCPP_STD_VER >= 23
1027template <class... _TTypes, class... _UTypes, template <class> class _TQual, template <class> class _UQual>
1028  requires requires { typename tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>; }
1029struct basic_common_reference<tuple<_TTypes...>, tuple<_UTypes...>, _TQual, _UQual> {
1030  using type = tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>;
1031};
1032
1033template <class... _TTypes, class... _UTypes>
1034  requires requires { typename tuple<common_type_t<_TTypes, _UTypes>...>; }
1035struct common_type<tuple<_TTypes...>, tuple<_UTypes...>> {
1036  using type = tuple<common_type_t<_TTypes, _UTypes>...>;
1037};
1038#    endif // _LIBCPP_STD_VER >= 23
1039
1040#    if _LIBCPP_STD_VER >= 17
1041template <class... _Tp>
1042tuple(_Tp...) -> tuple<_Tp...>;
1043template <class _Tp1, class _Tp2>
1044tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1045template <class _Alloc, class... _Tp>
1046tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1047template <class _Alloc, class _Tp1, class _Tp2>
1048tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1049template <class _Alloc, class... _Tp>
1050tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1051#    endif
1052
1053template <class... _Tp, __enable_if_t<__all<__is_swappable_v<_Tp>...>::value, int> = 0>
1054inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
1055swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u) noexcept(__all<__is_nothrow_swappable_v<_Tp>...>::value) {
1056  __t.swap(__u);
1057}
1058
1059#    if _LIBCPP_STD_VER >= 23
1060template <class... _Tp>
1061_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<__all<is_swappable_v<const _Tp>...>::value, void>
1062swap(const tuple<_Tp...>& __lhs,
1063     const tuple<_Tp...>& __rhs) noexcept(__all<is_nothrow_swappable_v<const _Tp>...>::value) {
1064  __lhs.swap(__rhs);
1065}
1066#    endif
1067
1068// get
1069
1070template <size_t _Ip, class... _Tp>
1071inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&
1072get(tuple<_Tp...>& __t) _NOEXCEPT {
1073  using type _LIBCPP_NODEBUG = typename tuple_element<_Ip, tuple<_Tp...> >::type;
1074  return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1075}
1076
1077template <size_t _Ip, class... _Tp>
1078inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1079get(const tuple<_Tp...>& __t) _NOEXCEPT {
1080  using type _LIBCPP_NODEBUG = typename tuple_element<_Ip, tuple<_Tp...> >::type;
1081  return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1082}
1083
1084template <size_t _Ip, class... _Tp>
1085inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1086get(tuple<_Tp...>&& __t) _NOEXCEPT {
1087  using type _LIBCPP_NODEBUG = typename tuple_element<_Ip, tuple<_Tp...> >::type;
1088  return static_cast<type&&>(static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1089}
1090
1091template <size_t _Ip, class... _Tp>
1092inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1093get(const tuple<_Tp...>&& __t) _NOEXCEPT {
1094  using type _LIBCPP_NODEBUG = typename tuple_element<_Ip, tuple<_Tp...> >::type;
1095  return static_cast<const type&&>(static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1096}
1097
1098#    if _LIBCPP_STD_VER >= 14
1099
1100template <class _T1, class... _Args>
1101inline _LIBCPP_HIDE_FROM_ABI constexpr _T1& get(tuple<_Args...>& __tup) noexcept {
1102  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1103}
1104
1105template <class _T1, class... _Args>
1106inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept {
1107  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1108}
1109
1110template <class _T1, class... _Args>
1111inline _LIBCPP_HIDE_FROM_ABI constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept {
1112  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1113}
1114
1115template <class _T1, class... _Args>
1116inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept {
1117  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1118}
1119
1120#    endif
1121
1122// tie
1123
1124template <class... _Tp>
1125inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&...> tie(_Tp&... __t) _NOEXCEPT {
1126  return tuple<_Tp&...>(__t...);
1127}
1128
1129template <class... _Tp>
1130inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<__unwrap_ref_decay_t<_Tp>...>
1131make_tuple(_Tp&&... __t) {
1132  return tuple<__unwrap_ref_decay_t<_Tp>...>(std::forward<_Tp>(__t)...);
1133}
1134
1135template <class... _Tp>
1136inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&&...> forward_as_tuple(_Tp&&... __t) _NOEXCEPT {
1137  return tuple<_Tp&&...>(std::forward<_Tp>(__t)...);
1138}
1139
1140template <size_t _Ip>
1141struct __tuple_equal {
1142  template <class _Tp, class _Up>
1143  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1144    return __tuple_equal<_Ip - 1>()(__x, __y) && std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y);
1145  }
1146};
1147
1148template <>
1149struct __tuple_equal<0> {
1150  template <class _Tp, class _Up>
1151  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1152    return true;
1153  }
1154};
1155
1156template <class... _Tp, class... _Up>
1157inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1158operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1159  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1160  return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1161}
1162
1163#    if _LIBCPP_STD_VER >= 20
1164
1165// operator<=>
1166
1167template <class... _Tp, class... _Up, size_t... _Is>
1168_LIBCPP_HIDE_FROM_ABI constexpr auto
1169__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
1170  common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
1171  static_cast<void>(
1172      ((__result = std::__synth_three_way(std::get<_Is>(__x), std::get<_Is>(__y)), __result != 0) || ...));
1173  return __result;
1174}
1175
1176template <class... _Tp, class... _Up>
1177  requires(sizeof...(_Tp) == sizeof...(_Up))
1178_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
1179operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1180  return std::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
1181}
1182
1183#    else // _LIBCPP_STD_VER >= 20
1184
1185template <class... _Tp, class... _Up>
1186inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1187operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1188  return !(__x == __y);
1189}
1190
1191template <size_t _Ip>
1192struct __tuple_less {
1193  template <class _Tp, class _Up>
1194  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1195    const size_t __idx = tuple_size<_Tp>::value - _Ip;
1196    if (std::get<__idx>(__x) < std::get<__idx>(__y))
1197      return true;
1198    if (std::get<__idx>(__y) < std::get<__idx>(__x))
1199      return false;
1200    return __tuple_less<_Ip - 1>()(__x, __y);
1201  }
1202};
1203
1204template <>
1205struct __tuple_less<0> {
1206  template <class _Tp, class _Up>
1207  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1208    return false;
1209  }
1210};
1211
1212template <class... _Tp, class... _Up>
1213inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1214operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1215  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1216  return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1217}
1218
1219template <class... _Tp, class... _Up>
1220inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1221operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1222  return __y < __x;
1223}
1224
1225template <class... _Tp, class... _Up>
1226inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1227operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1228  return !(__x < __y);
1229}
1230
1231template <class... _Tp, class... _Up>
1232inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1233operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1234  return !(__y < __x);
1235}
1236
1237#    endif // _LIBCPP_STD_VER >= 20
1238
1239// tuple_cat
1240
1241template <class _Tp, class _Up>
1242struct __tuple_cat_type;
1243
1244template <class... _Ttypes, class... _Utypes>
1245struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> > {
1246  using type _LIBCPP_NODEBUG = tuple<_Ttypes..., _Utypes...>;
1247};
1248
1249template <class _ResultTuple, bool _Is_Tuple0TupleLike, class... _Tuples>
1250struct __tuple_cat_return_1 {};
1251
1252template <class... _Types, class _Tuple0>
1253struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0> {
1254  using type _LIBCPP_NODEBUG =
1255      typename __tuple_cat_type< tuple<_Types...>,
1256                                 typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type;
1257};
1258
1259template <class... _Types, class _Tuple0, class _Tuple1, class... _Tuples>
1260struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1261    : public __tuple_cat_return_1<
1262          typename __tuple_cat_type< tuple<_Types...>,
1263                                     typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type,
1264          __tuple_like_ext<__libcpp_remove_reference_t<_Tuple1> >::value,
1265          _Tuple1,
1266          _Tuples...> {};
1267
1268template <class... _Tuples>
1269struct __tuple_cat_return;
1270
1271template <class _Tuple0, class... _Tuples>
1272struct __tuple_cat_return<_Tuple0, _Tuples...>
1273    : public __tuple_cat_return_1<tuple<>,
1274                                  __tuple_like_ext<__libcpp_remove_reference_t<_Tuple0> >::value,
1275                                  _Tuple0,
1276                                  _Tuples...> {};
1277
1278template <>
1279struct __tuple_cat_return<> {
1280  using type _LIBCPP_NODEBUG = tuple<>;
1281};
1282
1283inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<> tuple_cat() { return tuple<>(); }
1284
1285template <class _Rp, class _Indices, class _Tuple0, class... _Tuples>
1286struct __tuple_cat_return_ref_imp;
1287
1288template <class... _Types, size_t... _I0, class _Tuple0>
1289struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0> {
1290  using _T0 _LIBCPP_NODEBUG = __libcpp_remove_reference_t<_Tuple0>;
1291  typedef tuple<_Types..., __copy_cvref_t<_Tuple0, typename tuple_element<_I0, _T0>::type>&&...> type;
1292};
1293
1294template <class... _Types, size_t... _I0, class _Tuple0, class _Tuple1, class... _Tuples>
1295struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0, _Tuple1, _Tuples...>
1296    : public __tuple_cat_return_ref_imp<
1297          tuple<_Types...,
1298                __copy_cvref_t<_Tuple0, typename tuple_element<_I0, __libcpp_remove_reference_t<_Tuple0>>::type>&&...>,
1299          typename __make_tuple_indices<tuple_size<__libcpp_remove_reference_t<_Tuple1> >::value>::type,
1300          _Tuple1,
1301          _Tuples...> {};
1302
1303template <class _Tuple0, class... _Tuples>
1304struct __tuple_cat_return_ref
1305    : public __tuple_cat_return_ref_imp<
1306          tuple<>,
1307          typename __make_tuple_indices< tuple_size<__libcpp_remove_reference_t<_Tuple0> >::value >::type,
1308          _Tuple0,
1309          _Tuples...> {};
1310
1311template <class _Types, class _I0, class _J0>
1312struct __tuple_cat;
1313
1314template <class... _Types, size_t... _I0, size_t... _J0>
1315struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> > {
1316  template <class _Tuple0>
1317  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1318  typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1319  operator()(tuple<_Types...> __t, _Tuple0&& __t0) {
1320    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1321    return std::forward_as_tuple(
1322        std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...);
1323  }
1324
1325  template <class _Tuple0, class _Tuple1, class... _Tuples>
1326  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1327  typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1328  operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&&... __tpls) {
1329    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1330    using _T0 _LIBCPP_NODEBUG = __libcpp_remove_reference_t<_Tuple0>;
1331    using _T1 _LIBCPP_NODEBUG = __libcpp_remove_reference_t<_Tuple1>;
1332    return __tuple_cat<tuple<_Types..., __copy_cvref_t<_Tuple0, typename tuple_element<_J0, _T0>::type>&&...>,
1333                       typename __make_tuple_indices<sizeof...(_Types) + tuple_size<_T0>::value>::type,
1334                       typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1335        std::forward_as_tuple(
1336            std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...),
1337        std::forward<_Tuple1>(__t1),
1338        std::forward<_Tuples>(__tpls)...);
1339  }
1340};
1341
1342template <class _TupleDst, class _TupleSrc, size_t... _Indices>
1343inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _TupleDst
1344__tuple_cat_select_element_wise(_TupleSrc&& __src, __tuple_indices<_Indices...>) {
1345  static_assert(tuple_size<_TupleDst>::value == tuple_size<_TupleSrc>::value,
1346                "misuse of __tuple_cat_select_element_wise with tuples of different sizes");
1347  return _TupleDst(std::get<_Indices>(std::forward<_TupleSrc>(__src))...);
1348}
1349
1350template <class _Tuple0, class... _Tuples>
1351inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1352tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls) {
1353  using _T0 _LIBCPP_NODEBUG          = __libcpp_remove_reference_t<_Tuple0>;
1354  using _TRet _LIBCPP_NODEBUG        = typename __tuple_cat_return<_Tuple0, _Tuples...>::type;
1355  using _T0Indices _LIBCPP_NODEBUG   = typename __make_tuple_indices<tuple_size<_T0>::value>::type;
1356  using _TRetIndices _LIBCPP_NODEBUG = typename __make_tuple_indices<tuple_size<_TRet>::value>::type;
1357  return std::__tuple_cat_select_element_wise<_TRet>(
1358      __tuple_cat<tuple<>, __tuple_indices<>, _T0Indices>()(
1359          tuple<>(), std::forward<_Tuple0>(__t0), std::forward<_Tuples>(__tpls)...),
1360      _TRetIndices());
1361}
1362
1363template <class... _Tp, class _Alloc>
1364struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc> : true_type {};
1365
1366#    if _LIBCPP_STD_VER >= 17
1367#      define _LIBCPP_NOEXCEPT_RETURN(...)                                                                             \
1368        noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1369
1370// The _LIBCPP_NOEXCEPT_RETURN macro breaks formatting.
1371// clang-format off
1372template <class _Fn, class _Tuple, size_t... _Id>
1373inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto)
1374__apply_tuple_impl(_Fn&& __f, _Tuple&& __t, __tuple_indices<_Id...>)
1375    _LIBCPP_NOEXCEPT_RETURN(std::__invoke(std::forward<_Fn>(__f), std::get<_Id>(std::forward<_Tuple>(__t))...))
1376
1377template <class _Fn, class _Tuple>
1378inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) apply(_Fn&& __f, _Tuple&& __t)
1379    _LIBCPP_NOEXCEPT_RETURN(std::__apply_tuple_impl(
1380        std::forward<_Fn>(__f),
1381        std::forward<_Tuple>(__t),
1382        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1383
1384#if _LIBCPP_STD_VER >= 20
1385template <class _Tp, class _Tuple, size_t... _Idx>
1386inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1387  noexcept(noexcept(_Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...)))
1388  requires is_constructible_v<_Tp, decltype(std::get<_Idx>(std::forward<_Tuple>(__t)))...> {
1389  return _Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...);
1390}
1391#else
1392template <class _Tp, class _Tuple, size_t... _Idx>
1393inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>,
1394    enable_if_t<is_constructible_v<_Tp, decltype(std::get<_Idx>(std::forward<_Tuple>(__t)))...>> * = nullptr)
1395    _LIBCPP_NOEXCEPT_RETURN(_Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...))
1396#endif // _LIBCPP_STD_VER >= 20
1397
1398template <class _Tp, class _Tuple,
1399          class _Seq = typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type, class = void>
1400inline constexpr bool __can_make_from_tuple = false;
1401
1402template <class _Tp, class _Tuple, size_t... _Idx>
1403inline constexpr bool __can_make_from_tuple<_Tp, _Tuple, __tuple_indices<_Idx...>,
1404    enable_if_t<is_constructible_v<_Tp, decltype(std::get<_Idx>(std::declval<_Tuple>()))...>>> = true;
1405
1406// Based on LWG3528(https://wg21.link/LWG3528) and http://eel.is/c++draft/description#structure.requirements-9,
1407// the standard allows to impose requirements, we constraint std::make_from_tuple to make std::make_from_tuple
1408// SFINAE friendly and also avoid worse diagnostic messages. We still keep the constraints of std::__make_from_tuple_impl
1409// so that std::__make_from_tuple_impl will have the same advantages when used alone.
1410#if _LIBCPP_STD_VER >= 20
1411template <class _Tp, class _Tuple>
1412  requires __can_make_from_tuple<_Tp, _Tuple> // strengthen
1413#else
1414template <class _Tp, class _Tuple, class = enable_if_t<__can_make_from_tuple<_Tp, _Tuple>>> // strengthen
1415#endif // _LIBCPP_STD_VER >= 20
1416inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp make_from_tuple(_Tuple&& __t)
1417    _LIBCPP_NOEXCEPT_RETURN(std::__make_from_tuple_impl<_Tp>(
1418        std::forward<_Tuple>(__t), typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1419#    undef _LIBCPP_NOEXCEPT_RETURN
1420
1421#  endif // _LIBCPP_STD_VER >= 17
1422
1423#endif // !defined(_LIBCPP_CXX03_LANG)
1424
1425_LIBCPP_END_NAMESPACE_STD
1426
1427_LIBCPP_POP_MACROS
1428
1429// clang-format on
1430
1431#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1432#    include <cstddef>
1433#    include <exception>
1434#    include <iosfwd>
1435#    include <new>
1436#    include <type_traits>
1437#    include <typeinfo>
1438#    include <utility>
1439#  endif
1440#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
1441
1442#endif // _LIBCPP_TUPLE
1443