1// -*- C++ -*-
2//===------------------------ type_traits ---------------------------------===//
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_TYPE_TRAITS
11#define _LIBCPP_TYPE_TRAITS
12
13/*
14    type_traits synopsis
15
16namespace std
17{
18
19    // helper class:
20    template <class T, T v> struct integral_constant;
21    typedef integral_constant<bool, true>  true_type;   // C++11
22    typedef integral_constant<bool, false> false_type;  // C++11
23
24    template <bool B>                                   // C++14
25    using bool_constant = integral_constant<bool, B>;   // C++14
26    typedef bool_constant<true> true_type;              // C++14
27    typedef bool_constant<false> false_type;            // C++14
28
29    // helper traits
30    template <bool, class T = void> struct enable_if;
31    template <bool, class T, class F> struct conditional;
32
33    // Primary classification traits:
34    template <class T> struct is_void;
35    template <class T> struct is_null_pointer;  // C++14
36    template <class T> struct is_integral;
37    template <class T> struct is_floating_point;
38    template <class T> struct is_array;
39    template <class T> struct is_pointer;
40    template <class T> struct is_lvalue_reference;
41    template <class T> struct is_rvalue_reference;
42    template <class T> struct is_member_object_pointer;
43    template <class T> struct is_member_function_pointer;
44    template <class T> struct is_enum;
45    template <class T> struct is_union;
46    template <class T> struct is_class;
47    template <class T> struct is_function;
48
49    // Secondary classification traits:
50    template <class T> struct is_reference;
51    template <class T> struct is_arithmetic;
52    template <class T> struct is_fundamental;
53    template <class T> struct is_member_pointer;
54    template <class T> struct is_scoped_enum; // C++2b
55    template <class T> struct is_scalar;
56    template <class T> struct is_object;
57    template <class T> struct is_compound;
58
59    // Const-volatile properties and transformations:
60    template <class T> struct is_const;
61    template <class T> struct is_volatile;
62    template <class T> struct remove_const;
63    template <class T> struct remove_volatile;
64    template <class T> struct remove_cv;
65    template <class T> struct add_const;
66    template <class T> struct add_volatile;
67    template <class T> struct add_cv;
68
69    // Reference transformations:
70    template <class T> struct remove_reference;
71    template <class T> struct add_lvalue_reference;
72    template <class T> struct add_rvalue_reference;
73
74    // Pointer transformations:
75    template <class T> struct remove_pointer;
76    template <class T> struct add_pointer;
77
78    template<class T> struct type_identity;                     // C++20
79    template<class T>
80      using type_identity_t = typename type_identity<T>::type;  // C++20
81
82    // Integral properties:
83    template <class T> struct is_signed;
84    template <class T> struct is_unsigned;
85    template <class T> struct make_signed;
86    template <class T> struct make_unsigned;
87
88    // Array properties and transformations:
89    template <class T> struct rank;
90    template <class T, unsigned I = 0> struct extent;
91    template <class T> struct remove_extent;
92    template <class T> struct remove_all_extents;
93
94    template <class T> struct is_bounded_array;                 // C++20
95    template <class T> struct is_unbounded_array;               // C++20
96
97    // Member introspection:
98    template <class T> struct is_pod;
99    template <class T> struct is_trivial;
100    template <class T> struct is_trivially_copyable;
101    template <class T> struct is_standard_layout;
102    template <class T> struct is_literal_type; // Deprecated in C++17; removed in C++20
103    template <class T> struct is_empty;
104    template <class T> struct is_polymorphic;
105    template <class T> struct is_abstract;
106    template <class T> struct is_final; // C++14
107    template <class T> struct is_aggregate; // C++17
108
109    template <class T, class... Args> struct is_constructible;
110    template <class T>                struct is_default_constructible;
111    template <class T>                struct is_copy_constructible;
112    template <class T>                struct is_move_constructible;
113    template <class T, class U>       struct is_assignable;
114    template <class T>                struct is_copy_assignable;
115    template <class T>                struct is_move_assignable;
116    template <class T, class U>       struct is_swappable_with;       // C++17
117    template <class T>                struct is_swappable;            // C++17
118    template <class T>                struct is_destructible;
119
120    template <class T, class... Args> struct is_trivially_constructible;
121    template <class T>                struct is_trivially_default_constructible;
122    template <class T>                struct is_trivially_copy_constructible;
123    template <class T>                struct is_trivially_move_constructible;
124    template <class T, class U>       struct is_trivially_assignable;
125    template <class T>                struct is_trivially_copy_assignable;
126    template <class T>                struct is_trivially_move_assignable;
127    template <class T>                struct is_trivially_destructible;
128
129    template <class T, class... Args> struct is_nothrow_constructible;
130    template <class T>                struct is_nothrow_default_constructible;
131    template <class T>                struct is_nothrow_copy_constructible;
132    template <class T>                struct is_nothrow_move_constructible;
133    template <class T, class U>       struct is_nothrow_assignable;
134    template <class T>                struct is_nothrow_copy_assignable;
135    template <class T>                struct is_nothrow_move_assignable;
136    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
137    template <class T>                struct is_nothrow_swappable;      // C++17
138    template <class T>                struct is_nothrow_destructible;
139
140    template <class T> struct has_virtual_destructor;
141
142    template<class T> struct has_unique_object_representations;         // C++17
143
144    // Relationships between types:
145    template <class T, class U> struct is_same;
146    template <class Base, class Derived> struct is_base_of;
147
148    template <class From, class To> struct is_convertible;
149    template <typename From, typename To> struct is_nothrow_convertible;                  // C++20
150    template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
151
152    template <class Fn, class... ArgTypes> struct is_invocable;
153    template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
154
155    template <class Fn, class... ArgTypes> struct is_nothrow_invocable;
156    template <class R, class Fn, class... ArgTypes> struct is_nothrow_invocable_r;
157
158    // Alignment properties and transformations:
159    template <class T> struct alignment_of;
160    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
161        struct aligned_storage;
162    template <size_t Len, class... Types> struct aligned_union;
163    template <class T> struct remove_cvref; // C++20
164
165    template <class T> struct decay;
166    template <class... T> struct common_type;
167    template <class T> struct underlying_type;
168    template <class> class result_of; // undefined; deprecated in C++17; removed in C++20
169    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
170    template <class Fn, class... ArgTypes> struct invoke_result;  // C++17
171
172    // const-volatile modifications:
173    template <class T>
174      using remove_const_t    = typename remove_const<T>::type;  // C++14
175    template <class T>
176      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
177    template <class T>
178      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
179    template <class T>
180      using add_const_t       = typename add_const<T>::type;  // C++14
181    template <class T>
182      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
183    template <class T>
184      using add_cv_t          = typename add_cv<T>::type;  // C++14
185
186    // reference modifications:
187    template <class T>
188      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
189    template <class T>
190      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
191    template <class T>
192      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
193
194    // sign modifications:
195    template <class T>
196      using make_signed_t   = typename make_signed<T>::type;  // C++14
197    template <class T>
198      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
199
200    // array modifications:
201    template <class T>
202      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
203    template <class T>
204      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
205
206    template <class T>
207      inline constexpr bool is_bounded_array_v
208        = is_bounded_array<T>::value;                                     // C++20
209      inline constexpr bool is_unbounded_array_v
210        = is_unbounded_array<T>::value;                                   // C++20
211
212    // pointer modifications:
213    template <class T>
214      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
215    template <class T>
216      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
217
218    // other transformations:
219    template <size_t Len, size_t Align=default-alignment>
220      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
221    template <size_t Len, class... Types>
222      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
223    template <class T>
224      using remove_cvref_t    = typename remove_cvref<T>::type;  // C++20
225    template <class T>
226      using decay_t           = typename decay<T>::type;  // C++14
227    template <bool b, class T=void>
228      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
229    template <bool b, class T, class F>
230      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
231    template <class... T>
232      using common_type_t     = typename common_type<T...>::type;  // C++14
233    template <class T>
234      using underlying_type_t = typename underlying_type<T>::type;  // C++14
235    template <class T>
236      using result_of_t       = typename result_of<T>::type;  // C++14; deprecated in C++17; removed in C++20
237    template <class Fn, class... ArgTypes>
238      using invoke_result_t   = typename invoke_result<Fn, ArgTypes...>::type;  // C++17
239
240    template <class...>
241      using void_t = void;   // C++17
242
243      // See C++14 20.10.4.1, primary type categories
244      template <class T> inline constexpr bool is_void_v
245        = is_void<T>::value;                                             // C++17
246      template <class T> inline constexpr bool is_null_pointer_v
247        = is_null_pointer<T>::value;                                     // C++17
248      template <class T> inline constexpr bool is_integral_v
249        = is_integral<T>::value;                                         // C++17
250      template <class T> inline constexpr bool is_floating_point_v
251        = is_floating_point<T>::value;                                   // C++17
252      template <class T> inline constexpr bool is_array_v
253        = is_array<T>::value;                                            // C++17
254      template <class T> inline constexpr bool is_pointer_v
255        = is_pointer<T>::value;                                          // C++17
256      template <class T> inline constexpr bool is_lvalue_reference_v
257        = is_lvalue_reference<T>::value;                                 // C++17
258      template <class T> inline constexpr bool is_rvalue_reference_v
259        = is_rvalue_reference<T>::value;                                 // C++17
260      template <class T> inline constexpr bool is_member_object_pointer_v
261        = is_member_object_pointer<T>::value;                            // C++17
262      template <class T> inline constexpr bool is_member_function_pointer_v
263        = is_member_function_pointer<T>::value;                          // C++17
264      template <class T> inline constexpr bool is_enum_v
265        = is_enum<T>::value;                                             // C++17
266      template <class T> inline constexpr bool is_union_v
267        = is_union<T>::value;                                            // C++17
268      template <class T> inline constexpr bool is_class_v
269        = is_class<T>::value;                                            // C++17
270      template <class T> inline constexpr bool is_function_v
271        = is_function<T>::value;                                         // C++17
272
273      // See C++14 20.10.4.2, composite type categories
274      template <class T> inline constexpr bool is_reference_v
275        = is_reference<T>::value;                                        // C++17
276      template <class T> inline constexpr bool is_arithmetic_v
277        = is_arithmetic<T>::value;                                       // C++17
278      template <class T> inline constexpr bool is_fundamental_v
279        = is_fundamental<T>::value;                                      // C++17
280      template <class T> inline constexpr bool is_object_v
281        = is_object<T>::value;                                           // C++17
282      template <class T> inline constexpr bool is_scalar_v
283        = is_scalar<T>::value;                                           // C++17
284      template <class T> inline constexpr bool is_compound_v
285        = is_compound<T>::value;                                         // C++17
286      template <class T> inline constexpr bool is_member_pointer_v
287        = is_member_pointer<T>::value;                                   // C++17
288      template <class T> inline constexpr bool is_scoped_enum_v
289        = is_scoped_enum<T>::value;                                      // C++2b
290
291      // See C++14 20.10.4.3, type properties
292      template <class T> inline constexpr bool is_const_v
293        = is_const<T>::value;                                            // C++17
294      template <class T> inline constexpr bool is_volatile_v
295        = is_volatile<T>::value;                                         // C++17
296      template <class T> inline constexpr bool is_trivial_v
297        = is_trivial<T>::value;                                          // C++17
298      template <class T> inline constexpr bool is_trivially_copyable_v
299        = is_trivially_copyable<T>::value;                               // C++17
300      template <class T> inline constexpr bool is_standard_layout_v
301        = is_standard_layout<T>::value;                                  // C++17
302      template <class T> inline constexpr bool is_pod_v
303        = is_pod<T>::value;                                              // C++17
304      template <class T> inline constexpr bool is_literal_type_v
305        = is_literal_type<T>::value;                                     // C++17; deprecated in C++17; removed in C++20
306      template <class T> inline constexpr bool is_empty_v
307        = is_empty<T>::value;                                            // C++17
308      template <class T> inline constexpr bool is_polymorphic_v
309        = is_polymorphic<T>::value;                                      // C++17
310      template <class T> inline constexpr bool is_abstract_v
311        = is_abstract<T>::value;                                         // C++17
312      template <class T> inline constexpr bool is_final_v
313        = is_final<T>::value;                                            // C++17
314      template <class T> inline constexpr bool is_aggregate_v
315        = is_aggregate<T>::value;                                        // C++17
316      template <class T> inline constexpr bool is_signed_v
317        = is_signed<T>::value;                                           // C++17
318      template <class T> inline constexpr bool is_unsigned_v
319        = is_unsigned<T>::value;                                         // C++17
320      template <class T, class... Args> inline constexpr bool is_constructible_v
321        = is_constructible<T, Args...>::value;                           // C++17
322      template <class T> inline constexpr bool is_default_constructible_v
323        = is_default_constructible<T>::value;                            // C++17
324      template <class T> inline constexpr bool is_copy_constructible_v
325        = is_copy_constructible<T>::value;                               // C++17
326      template <class T> inline constexpr bool is_move_constructible_v
327        = is_move_constructible<T>::value;                               // C++17
328      template <class T, class U> inline constexpr bool is_assignable_v
329        = is_assignable<T, U>::value;                                    // C++17
330      template <class T> inline constexpr bool is_copy_assignable_v
331        = is_copy_assignable<T>::value;                                  // C++17
332      template <class T> inline constexpr bool is_move_assignable_v
333        = is_move_assignable<T>::value;                                  // C++17
334      template <class T, class U> inline constexpr bool is_swappable_with_v
335        = is_swappable_with<T, U>::value;                                // C++17
336      template <class T> inline constexpr bool is_swappable_v
337        = is_swappable<T>::value;                                        // C++17
338      template <class T> inline constexpr bool is_destructible_v
339        = is_destructible<T>::value;                                     // C++17
340      template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
341        = is_trivially_constructible<T, Args...>::value;                 // C++17
342      template <class T> inline constexpr bool is_trivially_default_constructible_v
343        = is_trivially_default_constructible<T>::value;                  // C++17
344      template <class T> inline constexpr bool is_trivially_copy_constructible_v
345        = is_trivially_copy_constructible<T>::value;                     // C++17
346      template <class T> inline constexpr bool is_trivially_move_constructible_v
347        = is_trivially_move_constructible<T>::value;                     // C++17
348      template <class T, class U> inline constexpr bool is_trivially_assignable_v
349        = is_trivially_assignable<T, U>::value;                          // C++17
350      template <class T> inline constexpr bool is_trivially_copy_assignable_v
351        = is_trivially_copy_assignable<T>::value;                        // C++17
352      template <class T> inline constexpr bool is_trivially_move_assignable_v
353        = is_trivially_move_assignable<T>::value;                        // C++17
354      template <class T> inline constexpr bool is_trivially_destructible_v
355        = is_trivially_destructible<T>::value;                           // C++17
356      template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
357        = is_nothrow_constructible<T, Args...>::value;                   // C++17
358      template <class T> inline constexpr bool is_nothrow_default_constructible_v
359        = is_nothrow_default_constructible<T>::value;                    // C++17
360      template <class T> inline constexpr bool is_nothrow_copy_constructible_v
361        = is_nothrow_copy_constructible<T>::value;                       // C++17
362      template <class T> inline constexpr bool is_nothrow_move_constructible_v
363        = is_nothrow_move_constructible<T>::value;                       // C++17
364      template <class T, class U> inline constexpr bool is_nothrow_assignable_v
365        = is_nothrow_assignable<T, U>::value;                            // C++17
366      template <class T> inline constexpr bool is_nothrow_copy_assignable_v
367        = is_nothrow_copy_assignable<T>::value;                          // C++17
368      template <class T> inline constexpr bool is_nothrow_move_assignable_v
369        = is_nothrow_move_assignable<T>::value;                          // C++17
370      template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
371        = is_nothrow_swappable_with<T, U>::value;                       // C++17
372      template <class T> inline constexpr bool is_nothrow_swappable_v
373        = is_nothrow_swappable<T>::value;                               // C++17
374      template <class T> inline constexpr bool is_nothrow_destructible_v
375        = is_nothrow_destructible<T>::value;                             // C++17
376      template <class T> inline constexpr bool has_virtual_destructor_v
377        = has_virtual_destructor<T>::value;                              // C++17
378      template<class T> inline constexpr bool has_unique_object_representations_v // C++17
379        = has_unique_object_representations<T>::value;
380
381      // See C++14 20.10.5, type property queries
382      template <class T> inline constexpr size_t alignment_of_v
383        = alignment_of<T>::value;                                        // C++17
384      template <class T> inline constexpr size_t rank_v
385        = rank<T>::value;                                                // C++17
386      template <class T, unsigned I = 0> inline constexpr size_t extent_v
387        = extent<T, I>::value;                                           // C++17
388
389      // See C++14 20.10.6, type relations
390      template <class T, class U> inline constexpr bool is_same_v
391        = is_same<T, U>::value;                                          // C++17
392      template <class Base, class Derived> inline constexpr bool is_base_of_v
393        = is_base_of<Base, Derived>::value;                              // C++17
394      template <class From, class To> inline constexpr bool is_convertible_v
395        = is_convertible<From, To>::value;                               // C++17
396      template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
397        = is_invocable<Fn, ArgTypes...>::value;                          // C++17
398      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
399        = is_invocable_r<R, Fn, ArgTypes...>::value;                     // C++17
400      template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
401        = is_nothrow_invocable<Fn, ArgTypes...>::value;                  // C++17
402      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
403        = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value;             // C++17
404
405      // [meta.logical], logical operator traits:
406      template<class... B> struct conjunction;                           // C++17
407      template<class... B>
408        inline constexpr bool conjunction_v = conjunction<B...>::value;  // C++17
409      template<class... B> struct disjunction;                           // C++17
410      template<class... B>
411        inline constexpr bool disjunction_v = disjunction<B...>::value;  // C++17
412      template<class B> struct negation;                                 // C++17
413      template<class B>
414        inline constexpr bool negation_v = negation<B>::value;           // C++17
415
416}
417
418*/
419#include <__config>
420#include <cstddef>
421#include <version>
422
423#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
424#pragma GCC system_header
425#endif
426
427_LIBCPP_BEGIN_NAMESPACE_STD
428
429template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
430template <class _Tp> class _LIBCPP_TEMPLATE_VIS reference_wrapper;
431template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
432
433template <class _Tp, _Tp __v>
434struct _LIBCPP_TEMPLATE_VIS integral_constant
435{
436  static _LIBCPP_CONSTEXPR const _Tp      value = __v;
437  typedef _Tp               value_type;
438  typedef integral_constant type;
439  _LIBCPP_INLINE_VISIBILITY
440  _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
441#if _LIBCPP_STD_VER > 11
442  _LIBCPP_INLINE_VISIBILITY
443  constexpr value_type operator ()() const _NOEXCEPT {return value;}
444#endif
445};
446
447template <class _Tp, _Tp __v>
448_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
449
450#if _LIBCPP_STD_VER > 14
451template <bool __b>
452using bool_constant = integral_constant<bool, __b>;
453#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
454#else
455#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
456#endif
457
458template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
459template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
460
461template <bool _Bp, class _Tp = void> using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type;
462
463#if _LIBCPP_STD_VER > 11
464template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
465#endif
466
467typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
468typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
469
470template <bool _Val>
471using _BoolConstant _LIBCPP_NODEBUG = integral_constant<bool, _Val>;
472
473template <bool> struct _MetaBase;
474template <>
475struct _MetaBase<true> {
476  template <class _Tp, class _Up>
477  using _SelectImpl _LIBCPP_NODEBUG = _Tp;
478  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
479  using _SelectApplyImpl _LIBCPP_NODEBUG = _FirstFn<_Args...>;
480  template <class _First, class...>
481  using _FirstImpl _LIBCPP_NODEBUG = _First;
482  template <class, class _Second, class...>
483  using _SecondImpl _LIBCPP_NODEBUG = _Second;
484  template <class _Result, class _First, class ..._Rest>
485  using _OrImpl _LIBCPP_NODEBUG = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
486};
487
488template <>
489struct _MetaBase<false> {
490  template <class _Tp, class _Up>
491  using _SelectImpl _LIBCPP_NODEBUG = _Up;
492  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
493  using _SelectApplyImpl _LIBCPP_NODEBUG = _SecondFn<_Args...>;
494  template <class _Result, class ...>
495  using _OrImpl _LIBCPP_NODEBUG = _Result;
496};
497template <bool _Cond, class _IfRes, class _ElseRes>
498using _If _LIBCPP_NODEBUG = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
499template <class ..._Rest>
500using _Or _LIBCPP_NODEBUG = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
501template <class _Pred>
502struct _Not : _BoolConstant<!_Pred::value> {};
503template <class ..._Args>
504using _FirstType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
505template <class ..._Args>
506using _SecondType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
507
508template <class ...> using __expand_to_true = true_type;
509template <class ..._Pred>
510__expand_to_true<__enable_if_t<_Pred::value>...> __and_helper(int);
511template <class ...>
512false_type __and_helper(...);
513template <class ..._Pred>
514using _And _LIBCPP_NODEBUG = decltype(__and_helper<_Pred...>(0));
515
516template <template <class...> class _Func, class ..._Args>
517struct _Lazy : _Func<_Args...> {};
518
519// Member detector base
520
521template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
522true_type __sfinae_test_impl(int);
523template <template <class...> class, class ...>
524false_type __sfinae_test_impl(...);
525
526template <template <class ...> class _Templ, class ..._Args>
527using _IsValidExpansion _LIBCPP_NODEBUG = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
528
529template <class>
530struct __void_t { typedef void type; };
531
532template <class _Tp>
533struct __identity { typedef _Tp type; };
534
535template <class _Tp>
536using __identity_t _LIBCPP_NODEBUG = typename __identity<_Tp>::type;
537
538template <class _Tp, bool>
539struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
540
541
542template <bool _Bp, class _If, class _Then>
543    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
544template <class _If, class _Then>
545    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
546
547#if _LIBCPP_STD_VER > 11
548template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
549#endif
550
551// is_same
552
553#if __has_keyword(__is_same)
554
555template <class _Tp, class _Up>
556struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
557
558#if _LIBCPP_STD_VER > 14
559template <class _Tp, class _Up>
560inline constexpr bool is_same_v = __is_same(_Tp, _Up);
561#endif
562
563#else
564
565template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
566template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
567
568#if _LIBCPP_STD_VER > 14
569template <class _Tp, class _Up>
570inline constexpr bool is_same_v = is_same<_Tp, _Up>::value;
571#endif
572
573#endif // __is_same
574
575template <class _Tp, class _Up>
576using _IsSame = _BoolConstant<
577#ifdef __clang__
578    __is_same(_Tp, _Up)
579#else
580    is_same<_Tp, _Up>::value
581#endif
582>;
583
584template <class _Tp, class _Up>
585using _IsNotSame = _BoolConstant<
586#ifdef __clang__
587    !__is_same(_Tp, _Up)
588#else
589    !is_same<_Tp, _Up>::value
590#endif
591>;
592
593
594template <class _Tp>
595using __test_for_primary_template = __enable_if_t<
596    _IsSame<_Tp, typename _Tp::__primary_template>::value
597  >;
598template <class _Tp>
599using __is_primary_template = _IsValidExpansion<
600    __test_for_primary_template, _Tp
601  >;
602
603struct __two {char __lx[2];};
604
605// helper class:
606
607// is_const
608
609#if __has_keyword(__is_const)
610
611template <class _Tp>
612struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
613
614#if _LIBCPP_STD_VER > 14
615template <class _Tp>
616inline constexpr bool is_const_v = __is_const(_Tp);
617#endif
618
619#else
620
621template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
622template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
623
624#if _LIBCPP_STD_VER > 14
625template <class _Tp>
626inline constexpr bool is_const_v = is_const<_Tp>::value;
627#endif
628
629#endif // __has_keyword(__is_const)
630
631// is_volatile
632
633#if __has_keyword(__is_volatile)
634
635template <class _Tp>
636struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
637
638#if _LIBCPP_STD_VER > 14
639template <class _Tp>
640inline constexpr bool is_volatile_v = __is_volatile(_Tp);
641#endif
642
643#else
644
645template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
646template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
647
648#if _LIBCPP_STD_VER > 14
649template <class _Tp>
650inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
651#endif
652
653#endif // __has_keyword(__is_volatile)
654
655// remove_const
656
657#if __has_keyword(__remove_const)
658
659template <class _Tp>
660struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
661
662#if _LIBCPP_STD_VER > 11
663template <class _Tp> using remove_const_t = __remove_const(_Tp);
664#endif
665
666#else
667
668template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
669template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
670#if _LIBCPP_STD_VER > 11
671template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
672#endif
673
674#endif // __has_keyword(__remove_const)
675
676// remove_volatile
677
678#if __has_keyword(__remove_volatile)
679
680template <class _Tp>
681struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
682
683#if _LIBCPP_STD_VER > 11
684template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
685#endif
686
687#else
688
689template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
690template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
691#if _LIBCPP_STD_VER > 11
692template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
693#endif
694
695#endif // __has_keyword(__remove_volatile)
696
697// remove_cv
698
699#if __has_keyword(__remove_cv)
700
701template <class _Tp>
702struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
703
704#if _LIBCPP_STD_VER > 11
705template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
706#endif
707
708#else
709
710template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
711{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
712#if _LIBCPP_STD_VER > 11
713template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
714#endif
715
716#endif // __has_keyword(__remove_cv)
717
718// is_void
719
720#if __has_keyword(__is_void)
721
722template <class _Tp>
723struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
724
725#if _LIBCPP_STD_VER > 14
726template <class _Tp>
727inline constexpr bool is_void_v = __is_void(_Tp);
728#endif
729
730#else
731
732template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
733    : public is_same<typename remove_cv<_Tp>::type, void> {};
734
735#if _LIBCPP_STD_VER > 14
736template <class _Tp>
737inline constexpr bool is_void_v = is_void<_Tp>::value;
738#endif
739
740#endif // __has_keyword(__is_void)
741
742// __is_nullptr_t
743
744template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
745template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
746
747template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
748    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
749
750#if _LIBCPP_STD_VER > 11
751template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
752    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
753
754#if _LIBCPP_STD_VER > 14
755template <class _Tp>
756inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
757#endif
758#endif // _LIBCPP_STD_VER > 11
759
760// is_integral
761
762#if __has_keyword(__is_integral)
763
764template <class _Tp>
765struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
766
767#if _LIBCPP_STD_VER > 14
768template <class _Tp>
769inline constexpr bool is_integral_v = __is_integral(_Tp);
770#endif
771
772#else
773
774template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
775    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
776
777#if _LIBCPP_STD_VER > 14
778template <class _Tp>
779inline constexpr bool is_integral_v = is_integral<_Tp>::value;
780#endif
781
782#endif // __has_keyword(__is_integral)
783
784// [basic.fundamental] defines five standard signed integer types;
785// __int128_t is an extended signed integer type.
786// The signed and unsigned integer types, plus bool and the
787// five types with "char" in their name, compose the "integral" types.
788
789template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
790template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
791template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
792template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
793template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
794template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
795#ifndef _LIBCPP_HAS_NO_INT128
796template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
797#endif
798
799template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
800template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
801template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
802template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
803template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
804template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
805#ifndef _LIBCPP_HAS_NO_INT128
806template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
807#endif
808
809// is_floating_point
810// <concepts> implements __libcpp_floating_point
811
812template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
813template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
814template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
815template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
816
817template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
818    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
819
820#if _LIBCPP_STD_VER > 14
821template <class _Tp>
822inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
823#endif
824
825// is_array
826
827#if __has_keyword(__is_array)
828
829template <class _Tp>
830struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
831
832#if _LIBCPP_STD_VER > 14
833template <class _Tp>
834inline constexpr bool is_array_v = __is_array(_Tp);
835#endif
836
837#else
838
839template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
840    : public false_type {};
841template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
842    : public true_type {};
843template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
844    : public true_type {};
845
846#if _LIBCPP_STD_VER > 14
847template <class _Tp>
848inline constexpr bool is_array_v = is_array<_Tp>::value;
849#endif
850
851#endif // __has_keyword(__is_array)
852
853// is_pointer
854
855// Before AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
856#if __has_keyword(__is_pointer) &&                                             \
857    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
858
859template<class _Tp>
860struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
861
862#if _LIBCPP_STD_VER > 14
863template <class _Tp>
864inline constexpr bool is_pointer_v = __is_pointer(_Tp);
865#endif
866
867#else // __has_keyword(__is_pointer)
868
869template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
870template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
871
872template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
873#if defined(_LIBCPP_HAS_OBJC_ARC)
874template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
875template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
876template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
877template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
878#endif
879
880template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
881    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
882
883#if _LIBCPP_STD_VER > 14
884template <class _Tp>
885inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
886#endif
887
888#endif // __has_keyword(__is_pointer)
889
890// is_reference
891
892#if __has_keyword(__is_lvalue_reference) && \
893    __has_keyword(__is_rvalue_reference) && \
894    __has_keyword(__is_reference)
895
896template<class _Tp>
897struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
898
899template<class _Tp>
900struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
901
902template<class _Tp>
903struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
904
905#if _LIBCPP_STD_VER > 14
906template <class _Tp>
907inline constexpr bool is_reference_v = __is_reference(_Tp);
908template <class _Tp>
909inline constexpr bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
910template <class _Tp>
911inline constexpr bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
912#endif
913
914#else // __has_keyword(__is_lvalue_reference) && etc...
915
916template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
917template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
918
919template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
920template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
921
922template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
923template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
924template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
925
926#if _LIBCPP_STD_VER > 14
927template <class _Tp>
928inline constexpr bool is_reference_v = is_reference<_Tp>::value;
929
930template <class _Tp>
931inline constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
932
933template <class _Tp>
934inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
935#endif
936
937#endif // __has_keyword(__is_lvalue_reference) && etc...
938
939// is_union
940
941#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
942
943template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
944    : public integral_constant<bool, __is_union(_Tp)> {};
945
946#else
947
948template <class _Tp> struct __libcpp_union : public false_type {};
949template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
950    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
951
952#endif
953
954#if _LIBCPP_STD_VER > 14
955template <class _Tp>
956inline constexpr bool is_union_v = is_union<_Tp>::value;
957#endif
958
959// is_class
960
961#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
962
963template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
964    : public integral_constant<bool, __is_class(_Tp)> {};
965
966#else
967
968namespace __is_class_imp
969{
970template <class _Tp> char  __test(int _Tp::*);
971template <class _Tp> __two __test(...);
972}
973
974template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
975    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
976
977#endif
978
979#if _LIBCPP_STD_VER > 14
980template <class _Tp>
981inline constexpr bool is_class_v = is_class<_Tp>::value;
982#endif
983
984// is_function
985
986template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
987    : public _BoolConstant<
988#ifdef __clang__
989    __is_function(_Tp)
990#else
991 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
992#endif
993    > {};
994
995
996#if _LIBCPP_STD_VER > 14
997template <class _Tp>
998inline constexpr bool is_function_v = is_function<_Tp>::value;
999#endif
1000
1001template <class _Tp> struct __libcpp_is_member_pointer {
1002  enum {
1003    __is_member = false,
1004    __is_func = false,
1005    __is_obj = false
1006  };
1007};
1008template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
1009  enum {
1010    __is_member = true,
1011    __is_func = is_function<_Tp>::value,
1012    __is_obj = !__is_func,
1013  };
1014};
1015
1016#if __has_keyword(__is_member_function_pointer)
1017
1018template<class _Tp>
1019struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1020    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1021
1022#if _LIBCPP_STD_VER > 14
1023template <class _Tp>
1024inline constexpr bool is_member_function_pointer_v = __is_member_function_pointer(_Tp);
1025#endif
1026
1027#else // __has_keyword(__is_member_function_pointer)
1028
1029template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1030    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1031
1032#if _LIBCPP_STD_VER > 14
1033template <class _Tp>
1034inline constexpr bool is_member_function_pointer_v = is_member_function_pointer<_Tp>::value;
1035#endif
1036
1037#endif // __has_keyword(__is_member_function_pointer)
1038
1039// is_member_pointer
1040
1041#if __has_keyword(__is_member_pointer)
1042
1043template<class _Tp>
1044struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
1045
1046#if _LIBCPP_STD_VER > 14
1047template <class _Tp>
1048inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
1049#endif
1050
1051#else // __has_keyword(__is_member_pointer)
1052
1053template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1054 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1055
1056#if _LIBCPP_STD_VER > 14
1057template <class _Tp>
1058inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
1059#endif
1060
1061#endif // __has_keyword(__is_member_pointer)
1062
1063// is_member_object_pointer
1064
1065#if __has_keyword(__is_member_object_pointer)
1066
1067template<class _Tp>
1068struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1069    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1070
1071#if _LIBCPP_STD_VER > 14
1072template <class _Tp>
1073inline constexpr bool is_member_object_pointer_v = __is_member_object_pointer(_Tp);
1074#endif
1075
1076#else // __has_keyword(__is_member_object_pointer)
1077
1078template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1079    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1080
1081#if _LIBCPP_STD_VER > 14
1082template <class _Tp>
1083inline constexpr bool is_member_object_pointer_v = is_member_object_pointer<_Tp>::value;
1084#endif
1085
1086#endif // __has_keyword(__is_member_object_pointer)
1087
1088// is_enum
1089
1090#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1091
1092template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1093    : public integral_constant<bool, __is_enum(_Tp)> {};
1094
1095#if _LIBCPP_STD_VER > 14
1096template <class _Tp>
1097inline constexpr bool is_enum_v = __is_enum(_Tp);
1098#endif
1099
1100#else
1101
1102template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1103    : public integral_constant<bool, !is_void<_Tp>::value             &&
1104                                     !is_integral<_Tp>::value         &&
1105                                     !is_floating_point<_Tp>::value   &&
1106                                     !is_array<_Tp>::value            &&
1107                                     !is_pointer<_Tp>::value          &&
1108                                     !is_reference<_Tp>::value        &&
1109                                     !is_member_pointer<_Tp>::value   &&
1110                                     !is_union<_Tp>::value            &&
1111                                     !is_class<_Tp>::value            &&
1112                                     !is_function<_Tp>::value         > {};
1113
1114#if _LIBCPP_STD_VER > 14
1115template <class _Tp>
1116inline constexpr bool is_enum_v = is_enum<_Tp>::value;
1117#endif
1118
1119#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1120
1121// is_arithmetic
1122
1123
1124template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1125    : public integral_constant<bool, is_integral<_Tp>::value      ||
1126                                     is_floating_point<_Tp>::value> {};
1127
1128#if _LIBCPP_STD_VER > 14
1129template <class _Tp>
1130inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
1131#endif
1132
1133// is_fundamental
1134
1135// Before Clang 10, __is_fundamental didn't work for nullptr_t.
1136// In C++03 nullptr_t is library-provided but must still count as "fundamental."
1137#if __has_keyword(__is_fundamental) &&                                         \
1138    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
1139    !defined(_LIBCPP_CXX03_LANG)
1140
1141template<class _Tp>
1142struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1143
1144#if _LIBCPP_STD_VER > 14
1145template <class _Tp>
1146inline constexpr bool is_fundamental_v = __is_fundamental(_Tp);
1147#endif
1148
1149#else // __has_keyword(__is_fundamental)
1150
1151template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1152    : public integral_constant<bool, is_void<_Tp>::value        ||
1153                                     __is_nullptr_t<_Tp>::value ||
1154                                     is_arithmetic<_Tp>::value> {};
1155
1156#if _LIBCPP_STD_VER > 14
1157template <class _Tp>
1158inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
1159#endif
1160
1161#endif // __has_keyword(__is_fundamental)
1162
1163// is_scalar
1164
1165// In C++03 nullptr_t is library-provided but must still count as "scalar."
1166#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1167
1168template<class _Tp>
1169struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1170
1171#if _LIBCPP_STD_VER > 14
1172template <class _Tp>
1173inline constexpr bool is_scalar_v = __is_scalar(_Tp);
1174#endif
1175
1176#else // __has_keyword(__is_scalar)
1177
1178template <class _Tp> struct __is_block : false_type {};
1179#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1180template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1181#endif
1182
1183template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1184    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1185                                     is_member_pointer<_Tp>::value ||
1186                                     is_pointer<_Tp>::value        ||
1187                                     __is_nullptr_t<_Tp>::value    ||
1188                                     __is_block<_Tp>::value        ||
1189                                     is_enum<_Tp>::value           > {};
1190
1191template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1192
1193#if _LIBCPP_STD_VER > 14
1194template <class _Tp>
1195inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
1196#endif
1197
1198#endif // __has_keyword(__is_scalar)
1199
1200// is_object
1201
1202#if __has_keyword(__is_object)
1203
1204template<class _Tp>
1205struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1206
1207#if _LIBCPP_STD_VER > 14
1208template <class _Tp>
1209inline constexpr bool is_object_v = __is_object(_Tp);
1210#endif
1211
1212#else // __has_keyword(__is_object)
1213
1214template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1215    : public integral_constant<bool, is_scalar<_Tp>::value ||
1216                                     is_array<_Tp>::value  ||
1217                                     is_union<_Tp>::value  ||
1218                                     is_class<_Tp>::value  > {};
1219
1220#if _LIBCPP_STD_VER > 14
1221template <class _Tp>
1222inline constexpr bool is_object_v = is_object<_Tp>::value;
1223#endif
1224
1225#endif // __has_keyword(__is_object)
1226
1227// is_compound
1228
1229// >= 11 because in C++03 nullptr isn't actually nullptr
1230#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1231
1232template<class _Tp>
1233struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1234
1235#if _LIBCPP_STD_VER > 14
1236template <class _Tp>
1237inline constexpr bool is_compound_v = __is_compound(_Tp);
1238#endif
1239
1240#else // __has_keyword(__is_compound)
1241
1242template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1243    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1244
1245#if _LIBCPP_STD_VER > 14
1246template <class _Tp>
1247inline constexpr bool is_compound_v = is_compound<_Tp>::value;
1248#endif
1249
1250#endif // __has_keyword(__is_compound)
1251
1252// __is_referenceable  [defns.referenceable]
1253
1254struct __is_referenceable_impl {
1255    template <class _Tp> static _Tp& __test(int);
1256    template <class _Tp> static __two __test(...);
1257};
1258
1259template <class _Tp>
1260struct __is_referenceable : integral_constant<bool,
1261    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1262
1263
1264// add_const
1265
1266template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1267  typedef _LIBCPP_NODEBUG const _Tp type;
1268};
1269
1270#if _LIBCPP_STD_VER > 11
1271template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1272#endif
1273
1274// add_volatile
1275
1276template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1277  typedef _LIBCPP_NODEBUG volatile _Tp type;
1278};
1279
1280#if _LIBCPP_STD_VER > 11
1281template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1282#endif
1283
1284// add_cv
1285template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1286  typedef _LIBCPP_NODEBUG const volatile _Tp type;
1287};
1288
1289#if _LIBCPP_STD_VER > 11
1290template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1291#endif
1292
1293// remove_reference
1294
1295#if __has_keyword(__remove_reference)
1296
1297template<class _Tp>
1298struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1299
1300#else // __has_keyword(__remove_reference)
1301
1302template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG _Tp type;};
1303template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG _Tp type;};
1304template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG _Tp type;};
1305
1306#if _LIBCPP_STD_VER > 11
1307template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1308#endif
1309
1310#endif // __has_keyword(__remove_reference)
1311
1312// add_lvalue_reference
1313
1314template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp  type; };
1315template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp& type; };
1316
1317template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1318{typedef _LIBCPP_NODEBUG typename  __add_lvalue_reference_impl<_Tp>::type type;};
1319
1320#if _LIBCPP_STD_VER > 11
1321template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1322#endif
1323
1324template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp   type; };
1325template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp&& type; };
1326
1327template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1328{typedef _LIBCPP_NODEBUG typename __add_rvalue_reference_impl<_Tp>::type type;};
1329
1330#if _LIBCPP_STD_VER > 11
1331template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1332#endif
1333
1334// Suppress deprecation notice for volatile-qualified return type resulting
1335// from volatile-qualified types _Tp.
1336_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1337template <class _Tp> _Tp&& __declval(int);
1338template <class _Tp> _Tp   __declval(long);
1339_LIBCPP_SUPPRESS_DEPRECATED_POP
1340
1341template <class _Tp>
1342decltype(__declval<_Tp>(0))
1343declval() _NOEXCEPT;
1344
1345// __uncvref
1346
1347template <class _Tp>
1348struct __uncvref  {
1349    typedef _LIBCPP_NODEBUG typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1350};
1351
1352template <class _Tp>
1353struct __unconstref {
1354    typedef _LIBCPP_NODEBUG typename remove_const<typename remove_reference<_Tp>::type>::type type;
1355};
1356
1357#ifndef _LIBCPP_CXX03_LANG
1358template <class _Tp>
1359using __uncvref_t _LIBCPP_NODEBUG = typename __uncvref<_Tp>::type;
1360#endif
1361
1362// __is_same_uncvref
1363
1364template <class _Tp, class _Up>
1365struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1366                                   typename __uncvref<_Up>::type> {};
1367
1368#if _LIBCPP_STD_VER > 17
1369// remove_cvref - same as __uncvref
1370template <class _Tp>
1371struct remove_cvref : public __uncvref<_Tp> {};
1372
1373template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1374#endif
1375
1376
1377struct __any
1378{
1379    __any(...);
1380};
1381
1382// remove_pointer
1383
1384template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG _Tp type;};
1385template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG _Tp type;};
1386template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG _Tp type;};
1387template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG _Tp type;};
1388template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG _Tp type;};
1389
1390#if _LIBCPP_STD_VER > 11
1391template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1392#endif
1393
1394// add_pointer
1395
1396template <class _Tp,
1397        bool = __is_referenceable<_Tp>::value ||
1398                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1399struct __add_pointer_impl
1400    {typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type* type;};
1401template <class _Tp> struct __add_pointer_impl<_Tp, false>
1402    {typedef _LIBCPP_NODEBUG _Tp type;};
1403
1404template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1405    {typedef _LIBCPP_NODEBUG typename __add_pointer_impl<_Tp>::type type;};
1406
1407#if _LIBCPP_STD_VER > 11
1408template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1409#endif
1410
1411// type_identity
1412#if _LIBCPP_STD_VER > 17
1413template<class _Tp> struct type_identity { typedef _Tp type; };
1414template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1415#endif
1416
1417// is_signed
1418
1419// Before Clang 10, __is_signed didn't work for floating-point types or enums.
1420#if __has_keyword(__is_signed) &&                                              \
1421    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000)
1422
1423template<class _Tp>
1424struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1425
1426#if _LIBCPP_STD_VER > 14
1427template <class _Tp>
1428inline constexpr bool is_signed_v = __is_signed(_Tp);
1429#endif
1430
1431#else // __has_keyword(__is_signed)
1432
1433template <class _Tp, bool = is_integral<_Tp>::value>
1434struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1435
1436template <class _Tp>
1437struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1438
1439template <class _Tp, bool = is_arithmetic<_Tp>::value>
1440struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1441
1442template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1443
1444template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1445
1446#if _LIBCPP_STD_VER > 14
1447template <class _Tp>
1448inline constexpr bool is_signed_v = is_signed<_Tp>::value;
1449#endif
1450
1451#endif // __has_keyword(__is_signed)
1452
1453// is_unsigned
1454
1455// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
1456// No currently-released version of AppleClang contains the fixed intrinsic.
1457#if __has_keyword(__is_unsigned) &&                                            \
1458    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
1459    !defined(_LIBCPP_APPLE_CLANG_VER)
1460
1461template<class _Tp>
1462struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
1463
1464#if _LIBCPP_STD_VER > 14
1465template <class _Tp>
1466inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
1467#endif
1468
1469#else // __has_keyword(__is_unsigned)
1470
1471template <class _Tp, bool = is_integral<_Tp>::value>
1472struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1473
1474template <class _Tp>
1475struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1476
1477template <class _Tp, bool = is_arithmetic<_Tp>::value>
1478struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1479
1480template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1481
1482template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1483
1484#if _LIBCPP_STD_VER > 14
1485template <class _Tp>
1486inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
1487#endif
1488
1489#endif // __has_keyword(__is_unsigned)
1490
1491// rank
1492
1493template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1494    : public integral_constant<size_t, 0> {};
1495template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1496    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1497template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1498    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1499
1500#if _LIBCPP_STD_VER > 14
1501template <class _Tp>
1502inline constexpr size_t rank_v = rank<_Tp>::value;
1503#endif
1504
1505// extent
1506
1507#if __has_keyword(__array_extent)
1508
1509template<class _Tp, size_t _Dim = 0>
1510struct _LIBCPP_TEMPLATE_VIS extent
1511    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1512
1513#if _LIBCPP_STD_VER > 14
1514template <class _Tp, unsigned _Ip = 0>
1515inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
1516#endif
1517
1518#else // __has_keyword(__array_extent)
1519
1520template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1521    : public integral_constant<size_t, 0> {};
1522template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1523    : public integral_constant<size_t, 0> {};
1524template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1525    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1526template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1527    : public integral_constant<size_t, _Np> {};
1528template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1529    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1530
1531#if _LIBCPP_STD_VER > 14
1532template <class _Tp, unsigned _Ip = 0>
1533inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
1534#endif
1535
1536#endif // __has_keyword(__array_extent)
1537
1538// remove_extent
1539
1540template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1541    {typedef _Tp type;};
1542template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1543    {typedef _Tp type;};
1544template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1545    {typedef _Tp type;};
1546
1547#if _LIBCPP_STD_VER > 11
1548template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1549#endif
1550
1551// remove_all_extents
1552
1553template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1554    {typedef _Tp type;};
1555template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1556    {typedef typename remove_all_extents<_Tp>::type type;};
1557template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1558    {typedef typename remove_all_extents<_Tp>::type type;};
1559
1560#if _LIBCPP_STD_VER > 11
1561template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1562#endif
1563
1564#if _LIBCPP_STD_VER > 17
1565// is_bounded_array
1566
1567template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1568template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1569
1570template <class _Tp>
1571inline constexpr
1572bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1573
1574// is_unbounded_array
1575
1576template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1577template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1578
1579template <class _Tp>
1580inline constexpr
1581bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1582#endif
1583
1584// decay
1585
1586template <class _Up, bool>
1587struct __decay {
1588    typedef _LIBCPP_NODEBUG typename remove_cv<_Up>::type type;
1589};
1590
1591template <class _Up>
1592struct __decay<_Up, true> {
1593public:
1594    typedef _LIBCPP_NODEBUG typename conditional
1595                     <
1596                         is_array<_Up>::value,
1597                         typename remove_extent<_Up>::type*,
1598                         typename conditional
1599                         <
1600                              is_function<_Up>::value,
1601                              typename add_pointer<_Up>::type,
1602                              typename remove_cv<_Up>::type
1603                         >::type
1604                     >::type type;
1605};
1606
1607template <class _Tp>
1608struct _LIBCPP_TEMPLATE_VIS decay
1609{
1610private:
1611    typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type _Up;
1612public:
1613    typedef _LIBCPP_NODEBUG typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1614};
1615
1616#if _LIBCPP_STD_VER > 11
1617template <class _Tp> using decay_t = typename decay<_Tp>::type;
1618#endif
1619
1620// is_abstract
1621
1622template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1623    : public integral_constant<bool, __is_abstract(_Tp)> {};
1624
1625#if _LIBCPP_STD_VER > 14
1626template <class _Tp>
1627inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
1628#endif
1629
1630// is_final
1631
1632template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1633__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1634
1635#if _LIBCPP_STD_VER > 11
1636template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1637is_final : public integral_constant<bool, __is_final(_Tp)> {};
1638#endif
1639
1640#if _LIBCPP_STD_VER > 14
1641template <class _Tp>
1642inline constexpr bool is_final_v = is_final<_Tp>::value;
1643#endif
1644
1645// is_aggregate
1646#if _LIBCPP_STD_VER > 14
1647
1648template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1649is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1650
1651template <class _Tp>
1652inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
1653
1654#endif // _LIBCPP_STD_VER > 14
1655
1656// is_base_of
1657
1658template <class _Bp, class _Dp>
1659struct _LIBCPP_TEMPLATE_VIS is_base_of
1660    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1661
1662#if _LIBCPP_STD_VER > 14
1663template <class _Bp, class _Dp>
1664inline constexpr bool is_base_of_v = is_base_of<_Bp, _Dp>::value;
1665#endif
1666
1667// __is_core_convertible
1668
1669// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
1670// We can't test for that, but we can test implicit convertibility by passing it
1671// to a function. Notice that __is_core_convertible<void,void> is false,
1672// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.
1673
1674template <class _Tp, class _Up, class = void>
1675struct __is_core_convertible : public false_type {};
1676
1677template <class _Tp, class _Up>
1678struct __is_core_convertible<_Tp, _Up, decltype(
1679    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
1680)> : public true_type {};
1681
1682// is_convertible
1683
1684#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1685
1686template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1687    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1688
1689#else  // __has_feature(is_convertible_to)
1690
1691namespace __is_convertible_imp
1692{
1693template <class _Tp> void  __test_convert(_Tp);
1694
1695template <class _From, class _To, class = void>
1696struct __is_convertible_test : public false_type {};
1697
1698template <class _From, class _To>
1699struct __is_convertible_test<_From, _To,
1700    decltype(__is_convertible_imp::__test_convert<_To>(declval<_From>()))> : public true_type
1701{};
1702
1703template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1704                     bool _IsFunction = is_function<_Tp>::value,
1705                     bool _IsVoid =     is_void<_Tp>::value>
1706                     struct __is_array_function_or_void                          {enum {value = 0};};
1707template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1708template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1709template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1710}
1711
1712template <class _Tp,
1713    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1714struct __is_convertible_check
1715{
1716    static const size_t __v = 0;
1717};
1718
1719template <class _Tp>
1720struct __is_convertible_check<_Tp, 0>
1721{
1722    static const size_t __v = sizeof(_Tp);
1723};
1724
1725template <class _T1, class _T2,
1726    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1727    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1728struct __is_convertible
1729    : public integral_constant<bool,
1730        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1731    >
1732{};
1733
1734template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1735template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1736template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1737template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1738
1739template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1740template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1741template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1742template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1743
1744template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1745template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1746template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1747template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1748
1749template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1750    : public __is_convertible<_T1, _T2>
1751{
1752    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1753    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1754};
1755
1756#endif // __has_feature(is_convertible_to)
1757
1758#if _LIBCPP_STD_VER > 14
1759template <class _From, class _To>
1760inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
1761#endif
1762
1763// is_nothrow_convertible
1764
1765#if _LIBCPP_STD_VER > 17
1766
1767template <typename _Tp>
1768static void __test_noexcept(_Tp) noexcept;
1769
1770template<typename _Fm, typename _To>
1771static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
1772__is_nothrow_convertible_test();
1773
1774template <typename _Fm, typename _To>
1775struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1776{ };
1777
1778template <typename _Fm, typename _To>
1779struct is_nothrow_convertible : _Or<
1780    _And<is_void<_To>, is_void<_Fm>>,
1781    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1782>::type { };
1783
1784template <typename _Fm, typename _To>
1785inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1786
1787#endif // _LIBCPP_STD_VER > 17
1788
1789// is_empty
1790
1791#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1792
1793template <class _Tp>
1794struct _LIBCPP_TEMPLATE_VIS is_empty
1795    : public integral_constant<bool, __is_empty(_Tp)> {};
1796
1797#else  // __has_feature(is_empty)
1798
1799template <class _Tp>
1800struct __is_empty1
1801    : public _Tp
1802{
1803    double __lx;
1804};
1805
1806struct __is_empty2
1807{
1808    double __lx;
1809};
1810
1811template <class _Tp, bool = is_class<_Tp>::value>
1812struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1813
1814template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1815
1816template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1817
1818#endif // __has_feature(is_empty)
1819
1820#if _LIBCPP_STD_VER > 14
1821template <class _Tp>
1822inline constexpr bool is_empty_v = is_empty<_Tp>::value;
1823#endif
1824
1825// is_polymorphic
1826
1827#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1828
1829template <class _Tp>
1830struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1831    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1832
1833#else
1834
1835template<typename _Tp> char &__is_polymorphic_impl(
1836    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1837                       int>::type);
1838template<typename _Tp> __two &__is_polymorphic_impl(...);
1839
1840template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1841    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1842
1843#endif // __has_feature(is_polymorphic)
1844
1845#if _LIBCPP_STD_VER > 14
1846template <class _Tp>
1847inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
1848#endif
1849
1850// has_virtual_destructor
1851
1852#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1853
1854template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1855    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1856
1857#else
1858
1859template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1860    : public false_type {};
1861
1862#endif
1863
1864#if _LIBCPP_STD_VER > 14
1865template <class _Tp>
1866inline constexpr bool has_virtual_destructor_v = has_virtual_destructor<_Tp>::value;
1867#endif
1868
1869// has_unique_object_representations
1870
1871#if _LIBCPP_STD_VER > 14
1872
1873template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1874    : public integral_constant<bool,
1875       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1876
1877template <class _Tp>
1878inline constexpr bool has_unique_object_representations_v = has_unique_object_representations<_Tp>::value;
1879
1880#endif
1881
1882// alignment_of
1883
1884template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1885    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1886
1887#if _LIBCPP_STD_VER > 14
1888template <class _Tp>
1889inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
1890#endif
1891
1892// aligned_storage
1893
1894template <class _Hp, class _Tp>
1895struct __type_list
1896{
1897    typedef _Hp _Head;
1898    typedef _Tp _Tail;
1899};
1900
1901struct __nat
1902{
1903#ifndef _LIBCPP_CXX03_LANG
1904    __nat() = delete;
1905    __nat(const __nat&) = delete;
1906    __nat& operator=(const __nat&) = delete;
1907    ~__nat() = delete;
1908#endif
1909};
1910
1911template <class _Tp>
1912struct __align_type
1913{
1914    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1915    typedef _Tp type;
1916};
1917
1918struct __struct_double {long double __lx;};
1919struct __struct_double4 {double __lx[4];};
1920
1921typedef
1922    __type_list<__align_type<unsigned char>,
1923    __type_list<__align_type<unsigned short>,
1924    __type_list<__align_type<unsigned int>,
1925    __type_list<__align_type<unsigned long>,
1926    __type_list<__align_type<unsigned long long>,
1927    __type_list<__align_type<double>,
1928    __type_list<__align_type<long double>,
1929    __type_list<__align_type<__struct_double>,
1930    __type_list<__align_type<__struct_double4>,
1931    __type_list<__align_type<int*>,
1932    __nat
1933    > > > > > > > > > > __all_types;
1934
1935template <size_t _Align>
1936struct _ALIGNAS(_Align) __fallback_overaligned {};
1937
1938template <class _TL, size_t _Align> struct __find_pod;
1939
1940template <class _Hp, size_t _Align>
1941struct __find_pod<__type_list<_Hp, __nat>, _Align>
1942{
1943    typedef typename conditional<
1944                             _Align == _Hp::value,
1945                             typename _Hp::type,
1946                             __fallback_overaligned<_Align>
1947                         >::type type;
1948};
1949
1950template <class _Hp, class _Tp, size_t _Align>
1951struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1952{
1953    typedef typename conditional<
1954                             _Align == _Hp::value,
1955                             typename _Hp::type,
1956                             typename __find_pod<_Tp, _Align>::type
1957                         >::type type;
1958};
1959
1960template <class _TL, size_t _Len> struct __find_max_align;
1961
1962template <class _Hp, size_t _Len>
1963struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
1964
1965template <size_t _Len, size_t _A1, size_t _A2>
1966struct __select_align
1967{
1968private:
1969    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
1970    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
1971public:
1972    static const size_t value = _Len < __max ? __min : __max;
1973};
1974
1975template <class _Hp, class _Tp, size_t _Len>
1976struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
1977    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
1978
1979template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1980struct _LIBCPP_TEMPLATE_VIS aligned_storage
1981{
1982    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
1983    union type
1984    {
1985        _Aligner __align;
1986        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
1987    };
1988};
1989
1990#if _LIBCPP_STD_VER > 11
1991template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1992    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
1993#endif
1994
1995#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
1996template <size_t _Len>\
1997struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
1998{\
1999    struct _ALIGNAS(n) type\
2000    {\
2001        unsigned char __lx[(_Len + n - 1)/n * n];\
2002    };\
2003}
2004
2005_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2006_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2007_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2008_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2009_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2010_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2011_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2012_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2013_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2014_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2015_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2016_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2017_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2018_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2019// PE/COFF does not support alignment beyond 8192 (=0x2000)
2020#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2021_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2022#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2023
2024#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2025
2026
2027// aligned_union
2028
2029template <size_t _I0, size_t ..._In>
2030struct __static_max;
2031
2032template <size_t _I0>
2033struct __static_max<_I0>
2034{
2035    static const size_t value = _I0;
2036};
2037
2038template <size_t _I0, size_t _I1, size_t ..._In>
2039struct __static_max<_I0, _I1, _In...>
2040{
2041    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2042                                             __static_max<_I1, _In...>::value;
2043};
2044
2045template <size_t _Len, class _Type0, class ..._Types>
2046struct aligned_union
2047{
2048    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2049                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2050    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2051                                             sizeof(_Types)...>::value;
2052    typedef typename aligned_storage<__len, alignment_value>::type type;
2053};
2054
2055#if _LIBCPP_STD_VER > 11
2056template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2057#endif
2058
2059template <class _Tp>
2060struct __numeric_type
2061{
2062   static void __test(...);
2063   static float __test(float);
2064   static double __test(char);
2065   static double __test(int);
2066   static double __test(unsigned);
2067   static double __test(long);
2068   static double __test(unsigned long);
2069   static double __test(long long);
2070   static double __test(unsigned long long);
2071   static double __test(double);
2072   static long double __test(long double);
2073
2074   typedef decltype(__test(declval<_Tp>())) type;
2075   static const bool value = _IsNotSame<type, void>::value;
2076};
2077
2078template <>
2079struct __numeric_type<void>
2080{
2081   static const bool value = true;
2082};
2083
2084// __promote
2085
2086template <class _A1, class _A2 = void, class _A3 = void,
2087          bool = __numeric_type<_A1>::value &&
2088                 __numeric_type<_A2>::value &&
2089                 __numeric_type<_A3>::value>
2090class __promote_imp
2091{
2092public:
2093    static const bool value = false;
2094};
2095
2096template <class _A1, class _A2, class _A3>
2097class __promote_imp<_A1, _A2, _A3, true>
2098{
2099private:
2100    typedef typename __promote_imp<_A1>::type __type1;
2101    typedef typename __promote_imp<_A2>::type __type2;
2102    typedef typename __promote_imp<_A3>::type __type3;
2103public:
2104    typedef decltype(__type1() + __type2() + __type3()) type;
2105    static const bool value = true;
2106};
2107
2108template <class _A1, class _A2>
2109class __promote_imp<_A1, _A2, void, true>
2110{
2111private:
2112    typedef typename __promote_imp<_A1>::type __type1;
2113    typedef typename __promote_imp<_A2>::type __type2;
2114public:
2115    typedef decltype(__type1() + __type2()) type;
2116    static const bool value = true;
2117};
2118
2119template <class _A1>
2120class __promote_imp<_A1, void, void, true>
2121{
2122public:
2123    typedef typename __numeric_type<_A1>::type type;
2124    static const bool value = true;
2125};
2126
2127template <class _A1, class _A2 = void, class _A3 = void>
2128class __promote : public __promote_imp<_A1, _A2, _A3> {};
2129
2130// make_signed / make_unsigned
2131
2132typedef
2133    __type_list<signed char,
2134    __type_list<signed short,
2135    __type_list<signed int,
2136    __type_list<signed long,
2137    __type_list<signed long long,
2138#ifndef _LIBCPP_HAS_NO_INT128
2139    __type_list<__int128_t,
2140#endif
2141    __nat
2142#ifndef _LIBCPP_HAS_NO_INT128
2143    >
2144#endif
2145    > > > > > __signed_types;
2146
2147typedef
2148    __type_list<unsigned char,
2149    __type_list<unsigned short,
2150    __type_list<unsigned int,
2151    __type_list<unsigned long,
2152    __type_list<unsigned long long,
2153#ifndef _LIBCPP_HAS_NO_INT128
2154    __type_list<__uint128_t,
2155#endif
2156    __nat
2157#ifndef _LIBCPP_HAS_NO_INT128
2158    >
2159#endif
2160    > > > > > __unsigned_types;
2161
2162template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2163
2164template <class _Hp, class _Tp, size_t _Size>
2165struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2166{
2167    typedef _LIBCPP_NODEBUG _Hp type;
2168};
2169
2170template <class _Hp, class _Tp, size_t _Size>
2171struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2172{
2173    typedef _LIBCPP_NODEBUG typename __find_first<_Tp, _Size>::type type;
2174};
2175
2176template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2177                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2178struct __apply_cv
2179{
2180    typedef _LIBCPP_NODEBUG _Up type;
2181};
2182
2183template <class _Tp, class _Up>
2184struct __apply_cv<_Tp, _Up, true, false>
2185{
2186    typedef _LIBCPP_NODEBUG const _Up type;
2187};
2188
2189template <class _Tp, class _Up>
2190struct __apply_cv<_Tp, _Up, false, true>
2191{
2192    typedef volatile _Up type;
2193};
2194
2195template <class _Tp, class _Up>
2196struct __apply_cv<_Tp, _Up, true, true>
2197{
2198    typedef const volatile _Up type;
2199};
2200
2201template <class _Tp, class _Up>
2202struct __apply_cv<_Tp&, _Up, false, false>
2203{
2204    typedef _Up& type;
2205};
2206
2207template <class _Tp, class _Up>
2208struct __apply_cv<_Tp&, _Up, true, false>
2209{
2210    typedef const _Up& type;
2211};
2212
2213template <class _Tp, class _Up>
2214struct __apply_cv<_Tp&, _Up, false, true>
2215{
2216    typedef volatile _Up& type;
2217};
2218
2219template <class _Tp, class _Up>
2220struct __apply_cv<_Tp&, _Up, true, true>
2221{
2222    typedef const volatile _Up& type;
2223};
2224
2225template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2226struct __make_signed {};
2227
2228template <class _Tp>
2229struct __make_signed<_Tp, true>
2230{
2231    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2232};
2233
2234template <> struct __make_signed<bool,               true> {};
2235template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2236template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2237template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2238template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2239template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2240template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2241template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2242template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2243#ifndef _LIBCPP_HAS_NO_INT128
2244template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2245template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2246#endif
2247
2248template <class _Tp>
2249struct _LIBCPP_TEMPLATE_VIS make_signed
2250{
2251    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2252};
2253
2254#if _LIBCPP_STD_VER > 11
2255template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2256#endif
2257
2258template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2259struct __make_unsigned {};
2260
2261template <class _Tp>
2262struct __make_unsigned<_Tp, true>
2263{
2264    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2265};
2266
2267template <> struct __make_unsigned<bool,               true> {};
2268template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2269template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2270template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2271template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2272template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2273template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2274template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2275template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2276#ifndef _LIBCPP_HAS_NO_INT128
2277template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2278template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2279#endif
2280
2281template <class _Tp>
2282struct _LIBCPP_TEMPLATE_VIS make_unsigned
2283{
2284    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2285};
2286
2287#if _LIBCPP_STD_VER > 11
2288template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2289#endif
2290
2291#ifndef _LIBCPP_CXX03_LANG
2292template <class _Tp>
2293_LIBCPP_HIDE_FROM_ABI constexpr
2294typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
2295    return static_cast<typename make_unsigned<_Tp>::type>(__x);
2296}
2297#endif
2298
2299#if _LIBCPP_STD_VER > 14
2300template <class...> using void_t = void;
2301#endif
2302
2303#if _LIBCPP_STD_VER > 17
2304// Let COND_RES(X, Y) be:
2305template <class _Tp, class _Up>
2306using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
2307
2308template <class _Tp, class _Up, class = void>
2309struct __common_type3 {};
2310
2311// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
2312template <class _Tp, class _Up>
2313struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
2314{
2315    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
2316};
2317
2318template <class _Tp, class _Up, class = void>
2319struct __common_type2_imp : __common_type3<_Tp, _Up> {};
2320#else
2321template <class _Tp, class _Up, class = void>
2322struct __common_type2_imp {};
2323#endif
2324
2325// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
2326template <class _Tp, class _Up>
2327struct __common_type2_imp<_Tp, _Up,
2328                          typename __void_t<decltype(
2329                                            true ? declval<_Tp>() : declval<_Up>()
2330                                            )>::type>
2331{
2332  typedef _LIBCPP_NODEBUG typename decay<decltype(
2333                         true ? declval<_Tp>() : declval<_Up>()
2334                         )>::type type;
2335};
2336
2337template <class, class = void>
2338struct __common_type_impl {};
2339
2340// Clang provides variadic templates in C++03 as an extension.
2341#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2342# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2343template <class... Tp>
2344struct __common_types;
2345template <class... _Tp>
2346struct _LIBCPP_TEMPLATE_VIS common_type;
2347#else
2348# define _LIBCPP_OPTIONAL_PACK(...)
2349struct __no_arg;
2350template <class _Tp, class _Up, class = __no_arg>
2351struct __common_types;
2352template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2353          class _Unused = __no_arg>
2354struct common_type {
2355  static_assert(sizeof(_Unused) == 0,
2356                "common_type accepts at most 3 arguments in C++03");
2357};
2358#endif // _LIBCPP_CXX03_LANG
2359
2360template <class _Tp, class _Up>
2361struct __common_type_impl<
2362    __common_types<_Tp, _Up>,
2363    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2364{
2365  typedef typename common_type<_Tp, _Up>::type type;
2366};
2367
2368template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2369struct __common_type_impl<
2370    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2371    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2372    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2373                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2374};
2375
2376// bullet 1 - sizeof...(Tp) == 0
2377
2378template <>
2379struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2380
2381// bullet 2 - sizeof...(Tp) == 1
2382
2383template <class _Tp>
2384struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2385    : public common_type<_Tp, _Tp> {};
2386
2387// bullet 3 - sizeof...(Tp) == 2
2388
2389// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
2390template <class _Tp, class _Up>
2391struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2392    : conditional<
2393        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2394        __common_type2_imp<_Tp, _Up>,
2395        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2396    >::type
2397{};
2398
2399// bullet 4 - sizeof...(Tp) > 2
2400
2401template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2402struct _LIBCPP_TEMPLATE_VIS
2403    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2404    : __common_type_impl<
2405          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2406
2407#undef _LIBCPP_OPTIONAL_PACK
2408
2409#if _LIBCPP_STD_VER > 11
2410template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2411#endif
2412
2413#if _LIBCPP_STD_VER > 11
2414// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
2415// top-level cv-qualifiers.
2416template <class _From, class _To>
2417struct __copy_cv
2418{
2419    using type = _To;
2420};
2421
2422template <class _From, class _To>
2423struct __copy_cv<const _From, _To>
2424{
2425    using type = add_const_t<_To>;
2426};
2427
2428template <class _From, class _To>
2429struct __copy_cv<volatile _From, _To>
2430{
2431    using type = add_volatile_t<_To>;
2432};
2433
2434template <class _From, class _To>
2435struct __copy_cv<const volatile _From, _To>
2436{
2437    using type = add_cv_t<_To>;
2438};
2439
2440template <class _From, class _To>
2441using __copy_cv_t = typename __copy_cv<_From, _To>::type;
2442
2443template <class _From, class _To>
2444struct __copy_cvref
2445{
2446    using type = __copy_cv_t<_From, _To>;
2447};
2448
2449template <class _From, class _To>
2450struct __copy_cvref<_From&, _To>
2451{
2452    using type = add_lvalue_reference_t<__copy_cv_t<_From, _To>>;
2453};
2454
2455template <class _From, class _To>
2456struct __copy_cvref<_From&&, _To>
2457{
2458    using type = add_rvalue_reference_t<__copy_cv_t<_From, _To>>;
2459};
2460
2461template <class _From, class _To>
2462using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
2463
2464#endif // _LIBCPP_STD_VER > 11
2465
2466// common_reference
2467#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2468// Let COND_RES(X, Y) be:
2469template <class _Xp, class _Yp>
2470using __cond_res =
2471    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
2472
2473// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
2474// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
2475// `U`.
2476// [Note: `XREF(A)` is `__xref<A>::template __apply`]
2477template <class _Tp>
2478struct __xref {
2479  template<class _Up>
2480  using __apply = __copy_cvref_t<_Tp, _Up>;
2481};
2482
2483// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
2484// and let COMMON-REF(A, B) be:
2485template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
2486struct __common_ref;
2487
2488template<class _Xp, class _Yp>
2489using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
2490
2491template<class _Xp, class _Yp>
2492using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
2493
2494
2495//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
2496//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
2497template<class _Ap, class _Bp, class _Xp, class _Yp>
2498requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
2499struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
2500{
2501    using __type = __cv_cond_res<_Xp, _Yp>;
2502};
2503
2504//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
2505template <class _Xp, class _Yp>
2506using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
2507
2508
2509//    .... If A and B are both rvalue reference types, C is well-formed, and
2510//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
2511template<class _Ap, class _Bp, class _Xp, class _Yp>
2512requires
2513  requires { typename __common_ref_C<_Xp, _Yp>; } &&
2514  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
2515  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
2516struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
2517{
2518    using __type = __common_ref_C<_Xp, _Yp>;
2519};
2520
2521//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
2522template <class _Tp, class _Up>
2523using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
2524
2525//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
2526//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
2527template<class _Ap, class _Bp, class _Xp, class _Yp>
2528requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
2529         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
2530struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
2531{
2532    using __type = __common_ref_D<_Xp, _Yp>;
2533};
2534
2535//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
2536//    COMMON-REF(A, B) is COMMON-REF(B, A).
2537template<class _Ap, class _Bp, class _Xp, class _Yp>
2538struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
2539
2540//    Otherwise, COMMON-REF(A, B) is ill-formed.
2541template<class _Ap, class _Bp, class _Xp, class _Yp>
2542struct __common_ref {};
2543
2544// Note C: For the common_reference trait applied to a parameter pack [...]
2545
2546template <class...>
2547struct common_reference;
2548
2549template <class... _Types>
2550using common_reference_t = typename common_reference<_Types...>::type;
2551
2552// bullet 1 - sizeof...(T) == 0
2553template<>
2554struct common_reference<> {};
2555
2556// bullet 2 - sizeof...(T) == 1
2557template <class _Tp>
2558struct common_reference<_Tp>
2559{
2560    using type = _Tp;
2561};
2562
2563// bullet 3 - sizeof...(T) == 2
2564template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
2565template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
2566template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
2567
2568// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
2569// the member typedef `type` denotes that type.
2570template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
2571
2572template <class _Tp, class _Up>
2573requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
2574struct __common_reference_sub_bullet1<_Tp, _Up>
2575{
2576    using type = __common_ref_t<_Tp, _Up>;
2577};
2578
2579// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
2580// is well-formed, then the member typedef `type` denotes that type.
2581template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
2582
2583template <class _Tp, class _Up>
2584using __basic_common_reference_t = typename basic_common_reference<
2585    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
2586    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
2587
2588template <class _Tp, class _Up>
2589requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
2590struct __common_reference_sub_bullet2<_Tp, _Up>
2591{
2592    using type = __basic_common_reference_t<_Tp, _Up>;
2593};
2594
2595// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
2596// then the member typedef `type` denotes that type.
2597template <class _Tp, class _Up>
2598requires requires { typename __cond_res<_Tp, _Up>; }
2599struct __common_reference_sub_bullet3<_Tp, _Up>
2600{
2601    using type = __cond_res<_Tp, _Up>;
2602};
2603
2604
2605// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
2606//                    then the member typedef `type` denotes that type.
2607//                  - Otherwise, there shall be no member `type`.
2608template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
2609
2610// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
2611//            any, as `common_reference_t<C, Rest...>`.
2612template <class _Tp, class _Up, class _Vp, class... _Rest>
2613requires requires { typename common_reference_t<_Tp, _Up>; }
2614struct common_reference<_Tp, _Up, _Vp, _Rest...>
2615    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
2616{};
2617
2618// bullet 5 - Otherwise, there shall be no member `type`.
2619template <class...> struct common_reference {};
2620
2621#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2622
2623// is_assignable
2624
2625template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG _Tp type; };
2626
2627#if __has_keyword(__is_assignable)
2628
2629template<class _Tp, class _Up>
2630struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2631
2632#if _LIBCPP_STD_VER > 14
2633template <class _Tp, class _Arg>
2634inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Arg);
2635#endif
2636
2637#else // __has_keyword(__is_assignable)
2638
2639template <class _Tp, class _Arg>
2640typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
2641__is_assignable_test(int);
2642
2643template <class, class>
2644false_type __is_assignable_test(...);
2645
2646
2647template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2648struct __is_assignable_imp
2649    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2650
2651template <class _Tp, class _Arg>
2652struct __is_assignable_imp<_Tp, _Arg, true>
2653    : public false_type
2654{
2655};
2656
2657template <class _Tp, class _Arg>
2658struct is_assignable
2659    : public __is_assignable_imp<_Tp, _Arg> {};
2660
2661#if _LIBCPP_STD_VER > 14
2662template <class _Tp, class _Arg>
2663inline constexpr bool is_assignable_v = is_assignable<_Tp, _Arg>::value;
2664#endif
2665
2666#endif // __has_keyword(__is_assignable)
2667
2668// is_copy_assignable
2669
2670template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2671    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2672                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2673
2674#if _LIBCPP_STD_VER > 14
2675template <class _Tp>
2676inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
2677#endif
2678
2679// is_move_assignable
2680
2681template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2682    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2683                           typename add_rvalue_reference<_Tp>::type> {};
2684
2685#if _LIBCPP_STD_VER > 14
2686template <class _Tp>
2687inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
2688#endif
2689
2690// is_destructible
2691
2692#if __has_keyword(__is_destructible)
2693
2694template<class _Tp>
2695struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2696
2697#if _LIBCPP_STD_VER > 14
2698template <class _Tp>
2699inline constexpr bool is_destructible_v = __is_destructible(_Tp);
2700#endif
2701
2702#else // __has_keyword(__is_destructible)
2703
2704//  if it's a reference, return true
2705//  if it's a function, return false
2706//  if it's   void,     return false
2707//  if it's an array of unknown bound, return false
2708//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
2709//    where _Up is remove_all_extents<_Tp>::type
2710
2711template <class>
2712struct __is_destructible_apply { typedef int type; };
2713
2714template <typename _Tp>
2715struct __is_destructor_wellformed {
2716    template <typename _Tp1>
2717    static char  __test (
2718        typename __is_destructible_apply<decltype(declval<_Tp1&>().~_Tp1())>::type
2719    );
2720
2721    template <typename _Tp1>
2722    static __two __test (...);
2723
2724    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2725};
2726
2727template <class _Tp, bool>
2728struct __destructible_imp;
2729
2730template <class _Tp>
2731struct __destructible_imp<_Tp, false>
2732   : public integral_constant<bool,
2733        __is_destructor_wellformed<typename remove_all_extents<_Tp>::type>::value> {};
2734
2735template <class _Tp>
2736struct __destructible_imp<_Tp, true>
2737    : public true_type {};
2738
2739template <class _Tp, bool>
2740struct __destructible_false;
2741
2742template <class _Tp>
2743struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, is_reference<_Tp>::value> {};
2744
2745template <class _Tp>
2746struct __destructible_false<_Tp, true> : public false_type {};
2747
2748template <class _Tp>
2749struct is_destructible
2750    : public __destructible_false<_Tp, is_function<_Tp>::value> {};
2751
2752template <class _Tp>
2753struct is_destructible<_Tp[]>
2754    : public false_type {};
2755
2756template <>
2757struct is_destructible<void>
2758    : public false_type {};
2759
2760#if _LIBCPP_STD_VER > 14
2761template <class _Tp>
2762inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
2763#endif
2764
2765#endif // __has_keyword(__is_destructible)
2766
2767template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2768struct __member_pointer_traits_imp
2769{
2770};
2771
2772template <class _Rp, class _Class, class ..._Param>
2773struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2774{
2775    typedef _Class _ClassType;
2776    typedef _Rp _ReturnType;
2777    typedef _Rp (_FnType) (_Param...);
2778};
2779
2780template <class _Rp, class _Class, class ..._Param>
2781struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2782{
2783    typedef _Class _ClassType;
2784    typedef _Rp _ReturnType;
2785    typedef _Rp (_FnType) (_Param..., ...);
2786};
2787
2788template <class _Rp, class _Class, class ..._Param>
2789struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2790{
2791    typedef _Class const _ClassType;
2792    typedef _Rp _ReturnType;
2793    typedef _Rp (_FnType) (_Param...);
2794};
2795
2796template <class _Rp, class _Class, class ..._Param>
2797struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2798{
2799    typedef _Class const _ClassType;
2800    typedef _Rp _ReturnType;
2801    typedef _Rp (_FnType) (_Param..., ...);
2802};
2803
2804template <class _Rp, class _Class, class ..._Param>
2805struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2806{
2807    typedef _Class volatile _ClassType;
2808    typedef _Rp _ReturnType;
2809    typedef _Rp (_FnType) (_Param...);
2810};
2811
2812template <class _Rp, class _Class, class ..._Param>
2813struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2814{
2815    typedef _Class volatile _ClassType;
2816    typedef _Rp _ReturnType;
2817    typedef _Rp (_FnType) (_Param..., ...);
2818};
2819
2820template <class _Rp, class _Class, class ..._Param>
2821struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2822{
2823    typedef _Class const volatile _ClassType;
2824    typedef _Rp _ReturnType;
2825    typedef _Rp (_FnType) (_Param...);
2826};
2827
2828template <class _Rp, class _Class, class ..._Param>
2829struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2830{
2831    typedef _Class const volatile _ClassType;
2832    typedef _Rp _ReturnType;
2833    typedef _Rp (_FnType) (_Param..., ...);
2834};
2835
2836#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2837
2838template <class _Rp, class _Class, class ..._Param>
2839struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2840{
2841    typedef _Class& _ClassType;
2842    typedef _Rp _ReturnType;
2843    typedef _Rp (_FnType) (_Param...);
2844};
2845
2846template <class _Rp, class _Class, class ..._Param>
2847struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2848{
2849    typedef _Class& _ClassType;
2850    typedef _Rp _ReturnType;
2851    typedef _Rp (_FnType) (_Param..., ...);
2852};
2853
2854template <class _Rp, class _Class, class ..._Param>
2855struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2856{
2857    typedef _Class const& _ClassType;
2858    typedef _Rp _ReturnType;
2859    typedef _Rp (_FnType) (_Param...);
2860};
2861
2862template <class _Rp, class _Class, class ..._Param>
2863struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2864{
2865    typedef _Class const& _ClassType;
2866    typedef _Rp _ReturnType;
2867    typedef _Rp (_FnType) (_Param..., ...);
2868};
2869
2870template <class _Rp, class _Class, class ..._Param>
2871struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2872{
2873    typedef _Class volatile& _ClassType;
2874    typedef _Rp _ReturnType;
2875    typedef _Rp (_FnType) (_Param...);
2876};
2877
2878template <class _Rp, class _Class, class ..._Param>
2879struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2880{
2881    typedef _Class volatile& _ClassType;
2882    typedef _Rp _ReturnType;
2883    typedef _Rp (_FnType) (_Param..., ...);
2884};
2885
2886template <class _Rp, class _Class, class ..._Param>
2887struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2888{
2889    typedef _Class const volatile& _ClassType;
2890    typedef _Rp _ReturnType;
2891    typedef _Rp (_FnType) (_Param...);
2892};
2893
2894template <class _Rp, class _Class, class ..._Param>
2895struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2896{
2897    typedef _Class const volatile& _ClassType;
2898    typedef _Rp _ReturnType;
2899    typedef _Rp (_FnType) (_Param..., ...);
2900};
2901
2902template <class _Rp, class _Class, class ..._Param>
2903struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2904{
2905    typedef _Class&& _ClassType;
2906    typedef _Rp _ReturnType;
2907    typedef _Rp (_FnType) (_Param...);
2908};
2909
2910template <class _Rp, class _Class, class ..._Param>
2911struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2912{
2913    typedef _Class&& _ClassType;
2914    typedef _Rp _ReturnType;
2915    typedef _Rp (_FnType) (_Param..., ...);
2916};
2917
2918template <class _Rp, class _Class, class ..._Param>
2919struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2920{
2921    typedef _Class const&& _ClassType;
2922    typedef _Rp _ReturnType;
2923    typedef _Rp (_FnType) (_Param...);
2924};
2925
2926template <class _Rp, class _Class, class ..._Param>
2927struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2928{
2929    typedef _Class const&& _ClassType;
2930    typedef _Rp _ReturnType;
2931    typedef _Rp (_FnType) (_Param..., ...);
2932};
2933
2934template <class _Rp, class _Class, class ..._Param>
2935struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2936{
2937    typedef _Class volatile&& _ClassType;
2938    typedef _Rp _ReturnType;
2939    typedef _Rp (_FnType) (_Param...);
2940};
2941
2942template <class _Rp, class _Class, class ..._Param>
2943struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2944{
2945    typedef _Class volatile&& _ClassType;
2946    typedef _Rp _ReturnType;
2947    typedef _Rp (_FnType) (_Param..., ...);
2948};
2949
2950template <class _Rp, class _Class, class ..._Param>
2951struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2952{
2953    typedef _Class const volatile&& _ClassType;
2954    typedef _Rp _ReturnType;
2955    typedef _Rp (_FnType) (_Param...);
2956};
2957
2958template <class _Rp, class _Class, class ..._Param>
2959struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2960{
2961    typedef _Class const volatile&& _ClassType;
2962    typedef _Rp _ReturnType;
2963    typedef _Rp (_FnType) (_Param..., ...);
2964};
2965
2966#endif // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2967
2968
2969template <class _Rp, class _Class>
2970struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2971{
2972    typedef _Class _ClassType;
2973    typedef _Rp _ReturnType;
2974};
2975
2976template <class _MP>
2977struct __member_pointer_traits
2978    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2979                    is_member_function_pointer<_MP>::value,
2980                    is_member_object_pointer<_MP>::value>
2981{
2982//     typedef ... _ClassType;
2983//     typedef ... _ReturnType;
2984//     typedef ... _FnType;
2985};
2986
2987
2988template <class _DecayedFp>
2989struct __member_pointer_class_type {};
2990
2991template <class _Ret, class _ClassType>
2992struct __member_pointer_class_type<_Ret _ClassType::*> {
2993  typedef _ClassType type;
2994};
2995
2996// template <class T, class... Args> struct is_constructible;
2997
2998template <class _Tp, class ..._Args>
2999struct _LIBCPP_TEMPLATE_VIS is_constructible
3000    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
3001{ };
3002
3003#if _LIBCPP_STD_VER > 14
3004template <class _Tp, class ..._Args>
3005inline constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
3006#endif
3007
3008// is_default_constructible
3009
3010template <class _Tp>
3011struct _LIBCPP_TEMPLATE_VIS is_default_constructible
3012    : public is_constructible<_Tp>
3013    {};
3014
3015#if _LIBCPP_STD_VER > 14
3016template <class _Tp>
3017inline constexpr bool is_default_constructible_v = is_default_constructible<_Tp>::value;
3018#endif
3019
3020#ifndef _LIBCPP_CXX03_LANG
3021// First of all, we can't implement this check in C++03 mode because the {}
3022// default initialization syntax isn't valid.
3023// Second, we implement the trait in a funny manner with two defaulted template
3024// arguments to workaround Clang's PR43454.
3025template <class _Tp>
3026void __test_implicit_default_constructible(_Tp);
3027
3028template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
3029struct __is_implicitly_default_constructible
3030    : false_type
3031{ };
3032
3033template <class _Tp>
3034struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
3035    : true_type
3036{ };
3037
3038template <class _Tp>
3039struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
3040    : false_type
3041{ };
3042#endif // !C++03
3043
3044// is_copy_constructible
3045
3046template <class _Tp>
3047struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
3048    : public is_constructible<_Tp,
3049                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3050
3051#if _LIBCPP_STD_VER > 14
3052template <class _Tp>
3053inline constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
3054#endif
3055
3056// is_move_constructible
3057
3058template <class _Tp>
3059struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3060    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3061    {};
3062
3063#if _LIBCPP_STD_VER > 14
3064template <class _Tp>
3065inline constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
3066#endif
3067
3068// is_trivially_constructible
3069
3070template <class _Tp, class... _Args>
3071struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3072    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3073{
3074};
3075
3076#if _LIBCPP_STD_VER > 14
3077template <class _Tp, class... _Args>
3078inline constexpr bool is_trivially_constructible_v = is_trivially_constructible<_Tp, _Args...>::value;
3079#endif
3080
3081// is_trivially_default_constructible
3082
3083template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3084    : public is_trivially_constructible<_Tp>
3085    {};
3086
3087#if _LIBCPP_STD_VER > 14
3088template <class _Tp>
3089inline constexpr bool is_trivially_default_constructible_v = is_trivially_default_constructible<_Tp>::value;
3090#endif
3091
3092// is_trivially_copy_constructible
3093
3094template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3095    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3096    {};
3097
3098#if _LIBCPP_STD_VER > 14
3099template <class _Tp>
3100inline constexpr bool is_trivially_copy_constructible_v = is_trivially_copy_constructible<_Tp>::value;
3101#endif
3102
3103// is_trivially_move_constructible
3104
3105template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3106    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3107    {};
3108
3109#if _LIBCPP_STD_VER > 14
3110template <class _Tp>
3111inline constexpr bool is_trivially_move_constructible_v = is_trivially_move_constructible<_Tp>::value;
3112#endif
3113
3114// is_trivially_assignable
3115
3116template <class _Tp, class _Arg>
3117struct is_trivially_assignable
3118    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3119{ };
3120
3121#if _LIBCPP_STD_VER > 14
3122template <class _Tp, class _Arg>
3123inline constexpr bool is_trivially_assignable_v = is_trivially_assignable<_Tp, _Arg>::value;
3124#endif
3125
3126// is_trivially_copy_assignable
3127
3128template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3129    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3130                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3131
3132#if _LIBCPP_STD_VER > 14
3133template <class _Tp>
3134inline constexpr bool is_trivially_copy_assignable_v = is_trivially_copy_assignable<_Tp>::value;
3135#endif
3136
3137// is_trivially_move_assignable
3138
3139template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3140    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3141                                     typename add_rvalue_reference<_Tp>::type>
3142    {};
3143
3144#if _LIBCPP_STD_VER > 14
3145template <class _Tp>
3146inline constexpr bool is_trivially_move_assignable_v = is_trivially_move_assignable<_Tp>::value;
3147#endif
3148
3149// is_trivially_destructible
3150
3151#if __has_keyword(__is_trivially_destructible)
3152
3153template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3154    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3155
3156#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3157
3158template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3159    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3160
3161#else
3162
3163template <class _Tp> struct __libcpp_trivial_destructor
3164    : public integral_constant<bool, is_scalar<_Tp>::value ||
3165                                     is_reference<_Tp>::value> {};
3166
3167template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3168    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3169
3170template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3171    : public false_type {};
3172
3173#endif
3174
3175#if _LIBCPP_STD_VER > 14
3176template <class _Tp>
3177inline constexpr bool is_trivially_destructible_v = is_trivially_destructible<_Tp>::value;
3178#endif
3179
3180// is_nothrow_constructible
3181
3182#if __has_keyword(__is_nothrow_constructible)
3183
3184template <class _Tp, class... _Args>
3185struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3186    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3187
3188#else
3189
3190template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3191
3192template <class _Tp, class... _Args>
3193struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3194    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3195{
3196};
3197
3198template <class _Tp>
3199void __implicit_conversion_to(_Tp) noexcept { }
3200
3201template <class _Tp, class _Arg>
3202struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3203    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3204{
3205};
3206
3207template <class _Tp, bool _IsReference, class... _Args>
3208struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3209    : public false_type
3210{
3211};
3212
3213template <class _Tp, class... _Args>
3214struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3215    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3216{
3217};
3218
3219template <class _Tp, size_t _Ns>
3220struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3221    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3222{
3223};
3224
3225#endif // _LIBCPP_HAS_NO_NOEXCEPT
3226
3227
3228#if _LIBCPP_STD_VER > 14
3229template <class _Tp, class ..._Args>
3230inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
3231#endif
3232
3233// is_nothrow_default_constructible
3234
3235template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3236    : public is_nothrow_constructible<_Tp>
3237    {};
3238
3239#if _LIBCPP_STD_VER > 14
3240template <class _Tp>
3241inline constexpr bool is_nothrow_default_constructible_v = is_nothrow_default_constructible<_Tp>::value;
3242#endif
3243
3244// is_nothrow_copy_constructible
3245
3246template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3247    : public is_nothrow_constructible<_Tp,
3248                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3249
3250#if _LIBCPP_STD_VER > 14
3251template <class _Tp>
3252inline constexpr bool is_nothrow_copy_constructible_v = is_nothrow_copy_constructible<_Tp>::value;
3253#endif
3254
3255// is_nothrow_move_constructible
3256
3257template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3258    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3259    {};
3260
3261#if _LIBCPP_STD_VER > 14
3262template <class _Tp>
3263inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<_Tp>::value;
3264#endif
3265
3266// is_nothrow_assignable
3267
3268#if __has_keyword(__is_nothrow_assignable)
3269
3270template <class _Tp, class _Arg>
3271struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3272    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3273
3274#else
3275
3276template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3277
3278template <class _Tp, class _Arg>
3279struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3280    : public false_type
3281{
3282};
3283
3284template <class _Tp, class _Arg>
3285struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3286    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
3287{
3288};
3289
3290template <class _Tp, class _Arg>
3291struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3292    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3293{
3294};
3295
3296#endif // _LIBCPP_HAS_NO_NOEXCEPT
3297
3298#if _LIBCPP_STD_VER > 14
3299template <class _Tp, class _Arg>
3300inline constexpr bool is_nothrow_assignable_v = is_nothrow_assignable<_Tp, _Arg>::value;
3301#endif
3302
3303// is_nothrow_copy_assignable
3304
3305template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3306    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3307                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3308
3309#if _LIBCPP_STD_VER > 14
3310template <class _Tp>
3311inline constexpr bool is_nothrow_copy_assignable_v = is_nothrow_copy_assignable<_Tp>::value;
3312#endif
3313
3314// is_nothrow_move_assignable
3315
3316template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3317    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3318                                     typename add_rvalue_reference<_Tp>::type>
3319    {};
3320
3321#if _LIBCPP_STD_VER > 14
3322template <class _Tp>
3323inline constexpr bool is_nothrow_move_assignable_v = is_nothrow_move_assignable<_Tp>::value;
3324#endif
3325
3326// is_nothrow_destructible
3327
3328#if !defined(_LIBCPP_CXX03_LANG)
3329
3330template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3331
3332template <class _Tp>
3333struct __libcpp_is_nothrow_destructible<false, _Tp>
3334    : public false_type
3335{
3336};
3337
3338template <class _Tp>
3339struct __libcpp_is_nothrow_destructible<true, _Tp>
3340    : public integral_constant<bool, noexcept(declval<_Tp>().~_Tp()) >
3341{
3342};
3343
3344template <class _Tp>
3345struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3346    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3347{
3348};
3349
3350template <class _Tp, size_t _Ns>
3351struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3352    : public is_nothrow_destructible<_Tp>
3353{
3354};
3355
3356template <class _Tp>
3357struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3358    : public true_type
3359{
3360};
3361
3362template <class _Tp>
3363struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3364    : public true_type
3365{
3366};
3367
3368#else
3369
3370template <class _Tp> struct __libcpp_nothrow_destructor
3371    : public integral_constant<bool, is_scalar<_Tp>::value ||
3372                                     is_reference<_Tp>::value> {};
3373
3374template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3375    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3376
3377template <class _Tp>
3378struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3379    : public false_type {};
3380
3381#endif
3382
3383#if _LIBCPP_STD_VER > 14
3384template <class _Tp>
3385inline constexpr bool is_nothrow_destructible_v = is_nothrow_destructible<_Tp>::value;
3386#endif
3387
3388// is_pod
3389
3390#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3391
3392template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3393    : public integral_constant<bool, __is_pod(_Tp)> {};
3394
3395#else
3396
3397template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3398    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3399                                     is_trivially_copy_constructible<_Tp>::value      &&
3400                                     is_trivially_copy_assignable<_Tp>::value    &&
3401                                     is_trivially_destructible<_Tp>::value> {};
3402
3403#endif
3404
3405#if _LIBCPP_STD_VER > 14
3406template <class _Tp>
3407inline constexpr bool is_pod_v = is_pod<_Tp>::value;
3408#endif
3409
3410// is_literal_type;
3411
3412#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3413template <class _Tp> struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 is_literal_type
3414    : public integral_constant<bool, __is_literal_type(_Tp)>
3415    {};
3416
3417#if _LIBCPP_STD_VER > 14
3418template <class _Tp>
3419_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
3420#endif // _LIBCPP_STD_VER > 14
3421#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3422
3423// is_standard_layout;
3424
3425template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3426#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3427    : public integral_constant<bool, __is_standard_layout(_Tp)>
3428#else
3429    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3430#endif
3431    {};
3432
3433#if _LIBCPP_STD_VER > 14
3434template <class _Tp>
3435inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
3436#endif
3437
3438// is_trivially_copyable;
3439
3440template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3441    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3442    {};
3443
3444#if _LIBCPP_STD_VER > 14
3445template <class _Tp>
3446inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
3447#endif
3448
3449// is_trivial;
3450
3451template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3452#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3453    : public integral_constant<bool, __is_trivial(_Tp)>
3454#else
3455    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3456                                 is_trivially_default_constructible<_Tp>::value>
3457#endif
3458    {};
3459
3460#if _LIBCPP_STD_VER > 14
3461template <class _Tp>
3462inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
3463#endif
3464
3465template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3466template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3467template <class _Tp> struct __is_reference_wrapper
3468    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3469
3470#ifndef _LIBCPP_CXX03_LANG
3471
3472template <class _Fp, class _A0,
3473         class _DecayFp = typename decay<_Fp>::type,
3474         class _DecayA0 = typename decay<_A0>::type,
3475         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3476using __enable_if_bullet1 = typename enable_if
3477    <
3478        is_member_function_pointer<_DecayFp>::value
3479        && is_base_of<_ClassT, _DecayA0>::value
3480    >::type;
3481
3482template <class _Fp, class _A0,
3483         class _DecayFp = typename decay<_Fp>::type,
3484         class _DecayA0 = typename decay<_A0>::type>
3485using __enable_if_bullet2 = typename enable_if
3486    <
3487        is_member_function_pointer<_DecayFp>::value
3488        && __is_reference_wrapper<_DecayA0>::value
3489    >::type;
3490
3491template <class _Fp, class _A0,
3492         class _DecayFp = typename decay<_Fp>::type,
3493         class _DecayA0 = typename decay<_A0>::type,
3494         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3495using __enable_if_bullet3 = typename enable_if
3496    <
3497        is_member_function_pointer<_DecayFp>::value
3498        && !is_base_of<_ClassT, _DecayA0>::value
3499        && !__is_reference_wrapper<_DecayA0>::value
3500    >::type;
3501
3502template <class _Fp, class _A0,
3503         class _DecayFp = typename decay<_Fp>::type,
3504         class _DecayA0 = typename decay<_A0>::type,
3505         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3506using __enable_if_bullet4 = typename enable_if
3507    <
3508        is_member_object_pointer<_DecayFp>::value
3509        && is_base_of<_ClassT, _DecayA0>::value
3510    >::type;
3511
3512template <class _Fp, class _A0,
3513         class _DecayFp = typename decay<_Fp>::type,
3514         class _DecayA0 = typename decay<_A0>::type>
3515using __enable_if_bullet5 = typename enable_if
3516    <
3517        is_member_object_pointer<_DecayFp>::value
3518        && __is_reference_wrapper<_DecayA0>::value
3519    >::type;
3520
3521template <class _Fp, class _A0,
3522         class _DecayFp = typename decay<_Fp>::type,
3523         class _DecayA0 = typename decay<_A0>::type,
3524         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3525using __enable_if_bullet6 = typename enable_if
3526    <
3527        is_member_object_pointer<_DecayFp>::value
3528        && !is_base_of<_ClassT, _DecayA0>::value
3529        && !__is_reference_wrapper<_DecayA0>::value
3530    >::type;
3531
3532// __invoke forward declarations
3533
3534// fall back - none of the bullets
3535
3536template <class ..._Args>
3537auto __invoke(__any, _Args&& ...__args) -> __nat;
3538
3539template <class ..._Args>
3540auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3541
3542// bullets 1, 2 and 3
3543
3544template <class _Fp, class _A0, class ..._Args,
3545          class = __enable_if_bullet1<_Fp, _A0>>
3546inline _LIBCPP_INLINE_VISIBILITY
3547_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3548__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3549    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
3550    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3551    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
3552
3553template <class _Fp, class _A0, class ..._Args,
3554          class = __enable_if_bullet1<_Fp, _A0>>
3555inline _LIBCPP_INLINE_VISIBILITY
3556_LIBCPP_CONSTEXPR auto
3557__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3558    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
3559    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3560    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
3561
3562template <class _Fp, class _A0, class ..._Args,
3563          class = __enable_if_bullet2<_Fp, _A0>>
3564inline _LIBCPP_INLINE_VISIBILITY
3565_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3566__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3567    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
3568    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3569    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
3570
3571template <class _Fp, class _A0, class ..._Args,
3572          class = __enable_if_bullet2<_Fp, _A0>>
3573inline _LIBCPP_INLINE_VISIBILITY
3574_LIBCPP_CONSTEXPR auto
3575__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3576    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
3577    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3578    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
3579
3580template <class _Fp, class _A0, class ..._Args,
3581          class = __enable_if_bullet3<_Fp, _A0>>
3582inline _LIBCPP_INLINE_VISIBILITY
3583_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3584__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3585    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
3586    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3587    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
3588
3589template <class _Fp, class _A0, class ..._Args,
3590          class = __enable_if_bullet3<_Fp, _A0>>
3591inline _LIBCPP_INLINE_VISIBILITY
3592_LIBCPP_CONSTEXPR auto
3593__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3594    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
3595    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3596    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
3597
3598// bullets 4, 5 and 6
3599
3600template <class _Fp, class _A0,
3601          class = __enable_if_bullet4<_Fp, _A0>>
3602inline _LIBCPP_INLINE_VISIBILITY
3603_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3604__invoke(_Fp&& __f, _A0&& __a0)
3605    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
3606    -> decltype(      static_cast<_A0&&>(__a0).*__f)
3607    { return          static_cast<_A0&&>(__a0).*__f; }
3608
3609template <class _Fp, class _A0,
3610          class = __enable_if_bullet4<_Fp, _A0>>
3611inline _LIBCPP_INLINE_VISIBILITY
3612_LIBCPP_CONSTEXPR auto
3613__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3614    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
3615    -> decltype(      static_cast<_A0&&>(__a0).*__f)
3616    { return          static_cast<_A0&&>(__a0).*__f; }
3617
3618template <class _Fp, class _A0,
3619          class = __enable_if_bullet5<_Fp, _A0>>
3620inline _LIBCPP_INLINE_VISIBILITY
3621_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3622__invoke(_Fp&& __f, _A0&& __a0)
3623    noexcept(noexcept(__a0.get().*__f))
3624    -> decltype(      __a0.get().*__f)
3625    { return          __a0.get().*__f; }
3626
3627template <class _Fp, class _A0,
3628          class = __enable_if_bullet5<_Fp, _A0>>
3629inline _LIBCPP_INLINE_VISIBILITY
3630_LIBCPP_CONSTEXPR auto
3631__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3632    noexcept(noexcept(__a0.get().*__f))
3633    -> decltype(      __a0.get().*__f)
3634    { return          __a0.get().*__f; }
3635
3636template <class _Fp, class _A0,
3637          class = __enable_if_bullet6<_Fp, _A0>>
3638inline _LIBCPP_INLINE_VISIBILITY
3639_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3640__invoke(_Fp&& __f, _A0&& __a0)
3641    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
3642    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
3643    { return          (*static_cast<_A0&&>(__a0)).*__f; }
3644
3645template <class _Fp, class _A0,
3646          class = __enable_if_bullet6<_Fp, _A0>>
3647inline _LIBCPP_INLINE_VISIBILITY
3648_LIBCPP_CONSTEXPR auto
3649__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3650    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
3651    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
3652    { return          (*static_cast<_A0&&>(__a0)).*__f; }
3653
3654// bullet 7
3655
3656template <class _Fp, class ..._Args>
3657inline _LIBCPP_INLINE_VISIBILITY
3658_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3659__invoke(_Fp&& __f, _Args&& ...__args)
3660    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
3661    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3662    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
3663
3664template <class _Fp, class ..._Args>
3665inline _LIBCPP_INLINE_VISIBILITY
3666_LIBCPP_CONSTEXPR auto
3667__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3668    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
3669    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3670    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
3671
3672// __invokable
3673template <class _Ret, class _Fp, class ..._Args>
3674struct __invokable_r
3675{
3676  template <class _XFp, class ..._XArgs>
3677  static auto __try_call(int) -> decltype(
3678    _VSTD::__invoke(declval<_XFp>(), declval<_XArgs>()...));
3679  template <class _XFp, class ..._XArgs>
3680  static __nat __try_call(...);
3681
3682  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3683  // or incomplete array types as required by the standard.
3684  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3685
3686  using type =
3687  typename conditional<
3688      _IsNotSame<_Result, __nat>::value,
3689      typename conditional<
3690          is_void<_Ret>::value,
3691          true_type,
3692          is_convertible<_Result, _Ret>
3693      >::type,
3694      false_type
3695  >::type;
3696  static const bool value = type::value;
3697};
3698template <class _Fp, class ..._Args>
3699using __invokable = __invokable_r<void, _Fp, _Args...>;
3700
3701template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3702struct __nothrow_invokable_r_imp {
3703  static const bool value = false;
3704};
3705
3706template <class _Ret, class _Fp, class ..._Args>
3707struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3708{
3709    typedef __nothrow_invokable_r_imp _ThisT;
3710
3711    template <class _Tp>
3712    static void __test_noexcept(_Tp) noexcept;
3713
3714    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3715        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...)));
3716};
3717
3718template <class _Ret, class _Fp, class ..._Args>
3719struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3720{
3721    static const bool value = noexcept(
3722        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...));
3723};
3724
3725template <class _Ret, class _Fp, class ..._Args>
3726using __nothrow_invokable_r =
3727    __nothrow_invokable_r_imp<
3728            __invokable_r<_Ret, _Fp, _Args...>::value,
3729            is_void<_Ret>::value,
3730            _Ret, _Fp, _Args...
3731    >;
3732
3733template <class _Fp, class ..._Args>
3734using __nothrow_invokable =
3735    __nothrow_invokable_r_imp<
3736            __invokable<_Fp, _Args...>::value,
3737            true, void, _Fp, _Args...
3738    >;
3739
3740template <class _Fp, class ..._Args>
3741struct __invoke_of
3742    : public enable_if<
3743        __invokable<_Fp, _Args...>::value,
3744        typename __invokable_r<void, _Fp, _Args...>::_Result>
3745{
3746};
3747
3748#endif // _LIBCPP_CXX03_LANG
3749
3750// result_of
3751
3752#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3753template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
3754
3755#ifndef _LIBCPP_CXX03_LANG
3756
3757template <class _Fp, class ..._Args>
3758class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3759    : public __invoke_of<_Fp, _Args...>
3760{
3761};
3762
3763#else // C++03
3764
3765template <class _Fn, bool, bool>
3766class __result_of
3767{
3768};
3769
3770template <class _Fn, class ..._Args>
3771class __result_of<_Fn(_Args...), true, false>
3772{
3773public:
3774    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
3775};
3776
3777template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
3778struct __result_of_mp;
3779
3780// member function pointer
3781
3782template <class _MP, class _Tp>
3783struct __result_of_mp<_MP, _Tp, true>
3784{
3785    using type = typename __member_pointer_traits<_MP>::_ReturnType;
3786};
3787
3788// member data pointer
3789
3790template <class _MP, class _Tp, bool>
3791struct __result_of_mdp;
3792
3793template <class _Rp, class _Class, class _Tp>
3794struct __result_of_mdp<_Rp _Class::*, _Tp, false>
3795{
3796    using type = typename __apply_cv<decltype(*declval<_Tp>()), _Rp>::type&;
3797};
3798
3799template <class _Rp, class _Class, class _Tp>
3800struct __result_of_mdp<_Rp _Class::*, _Tp, true>
3801{
3802    using type = typename __apply_cv<_Tp, _Rp>::type&;
3803};
3804
3805template <class _Rp, class _Class, class _Tp>
3806struct __result_of_mp<_Rp _Class::*, _Tp, false>
3807    : public __result_of_mdp<_Rp _Class::*, _Tp,
3808            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
3809{
3810};
3811
3812template <class _Fn, class _Tp>
3813class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
3814    : public __result_of_mp<typename remove_reference<_Fn>::type,
3815                            _Tp,
3816                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3817{
3818};
3819
3820template <class _Fn, class _Tp, class ..._Args>
3821class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
3822    : public __result_of_mp<typename remove_reference<_Fn>::type,
3823                            _Tp,
3824                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3825{
3826};
3827
3828template <class _Fn, class ..._Args>
3829class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
3830    : public __result_of<_Fn(_Args...),
3831                         is_class<typename remove_reference<_Fn>::type>::value ||
3832                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3833                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3834                        >
3835{
3836};
3837
3838#endif // C++03
3839
3840#if _LIBCPP_STD_VER > 11
3841template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
3842#endif // _LIBCPP_STD_VER > 11
3843#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3844
3845#if _LIBCPP_STD_VER > 14
3846
3847// invoke_result
3848
3849template <class _Fn, class... _Args>
3850struct _LIBCPP_TEMPLATE_VIS invoke_result
3851    : __invoke_of<_Fn, _Args...>
3852{
3853};
3854
3855template <class _Fn, class... _Args>
3856using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3857
3858// is_invocable
3859
3860template <class _Fn, class ..._Args>
3861struct _LIBCPP_TEMPLATE_VIS is_invocable
3862    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
3863
3864template <class _Ret, class _Fn, class ..._Args>
3865struct _LIBCPP_TEMPLATE_VIS is_invocable_r
3866    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
3867
3868template <class _Fn, class ..._Args>
3869inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
3870
3871template <class _Ret, class _Fn, class ..._Args>
3872inline constexpr bool is_invocable_r_v = is_invocable_r<_Ret, _Fn, _Args...>::value;
3873
3874// is_nothrow_invocable
3875
3876template <class _Fn, class ..._Args>
3877struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
3878    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
3879
3880template <class _Ret, class _Fn, class ..._Args>
3881struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
3882    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
3883
3884template <class _Fn, class ..._Args>
3885inline constexpr bool is_nothrow_invocable_v = is_nothrow_invocable<_Fn, _Args...>::value;
3886
3887template <class _Ret, class _Fn, class ..._Args>
3888inline constexpr bool is_nothrow_invocable_r_v = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3889
3890#endif // _LIBCPP_STD_VER > 14
3891
3892// __swappable
3893
3894template <class _Tp> struct __is_swappable;
3895template <class _Tp> struct __is_nothrow_swappable;
3896
3897
3898#ifndef _LIBCPP_CXX03_LANG
3899template <class _Tp>
3900using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
3901#else
3902template <class>
3903using __swap_result_t = void;
3904#endif
3905
3906template <class _Tp>
3907inline _LIBCPP_INLINE_VISIBILITY
3908_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
3909swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
3910                                    is_nothrow_move_assignable<_Tp>::value);
3911
3912template<class _Tp, size_t _Np>
3913inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3914typename enable_if<
3915    __is_swappable<_Tp>::value
3916>::type
3917swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
3918
3919namespace __detail
3920{
3921// ALL generic swap overloads MUST already have a declaration available at this point.
3922
3923template <class _Tp, class _Up = _Tp,
3924          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
3925struct __swappable_with
3926{
3927    template <class _LHS, class _RHS>
3928    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
3929    __test_swap(int);
3930    template <class, class>
3931    static __nat __test_swap(long);
3932
3933    // Extra parens are needed for the C++03 definition of decltype.
3934    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
3935    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
3936
3937    static const bool value = _IsNotSame<__swap1, __nat>::value
3938                           && _IsNotSame<__swap2, __nat>::value;
3939};
3940
3941template <class _Tp, class _Up>
3942struct __swappable_with<_Tp, _Up,  false> : false_type {};
3943
3944template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
3945struct __nothrow_swappable_with {
3946  static const bool value =
3947#ifndef _LIBCPP_HAS_NO_NOEXCEPT
3948      noexcept(swap(declval<_Tp>(), declval<_Up>()))
3949  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
3950#else
3951      false;
3952#endif
3953};
3954
3955template <class _Tp, class _Up>
3956struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
3957
3958}  // __detail
3959
3960template <class _Tp>
3961struct __is_swappable
3962    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
3963{
3964};
3965
3966template <class _Tp>
3967struct __is_nothrow_swappable
3968    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
3969{
3970};
3971
3972#if _LIBCPP_STD_VER > 14
3973
3974template <class _Tp, class _Up>
3975struct _LIBCPP_TEMPLATE_VIS is_swappable_with
3976    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
3977{
3978};
3979
3980template <class _Tp>
3981struct _LIBCPP_TEMPLATE_VIS is_swappable
3982    : public conditional<
3983        __is_referenceable<_Tp>::value,
3984        is_swappable_with<
3985            typename add_lvalue_reference<_Tp>::type,
3986            typename add_lvalue_reference<_Tp>::type>,
3987        false_type
3988    >::type
3989{
3990};
3991
3992template <class _Tp, class _Up>
3993struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
3994    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
3995{
3996};
3997
3998template <class _Tp>
3999struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
4000    : public conditional<
4001        __is_referenceable<_Tp>::value,
4002        is_nothrow_swappable_with<
4003            typename add_lvalue_reference<_Tp>::type,
4004            typename add_lvalue_reference<_Tp>::type>,
4005        false_type
4006    >::type
4007{
4008};
4009
4010template <class _Tp, class _Up>
4011inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
4012
4013template <class _Tp>
4014inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;
4015
4016template <class _Tp, class _Up>
4017inline constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
4018
4019template <class _Tp>
4020inline constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
4021
4022#endif // _LIBCPP_STD_VER > 14
4023
4024template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4025
4026template <class _Tp>
4027struct __underlying_type_impl<_Tp, false> {};
4028
4029template <class _Tp>
4030struct __underlying_type_impl<_Tp, true>
4031{
4032    typedef __underlying_type(_Tp) type;
4033};
4034
4035template <class _Tp>
4036struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4037
4038#if _LIBCPP_STD_VER > 11
4039template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4040#endif
4041
4042template <class _Tp, bool = is_enum<_Tp>::value>
4043struct __sfinae_underlying_type
4044{
4045    typedef typename underlying_type<_Tp>::type type;
4046    typedef decltype(((type)1) + 0) __promoted_type;
4047};
4048
4049template <class _Tp>
4050struct __sfinae_underlying_type<_Tp, false> {};
4051
4052inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4053int __convert_to_integral(int __val) { return __val; }
4054
4055inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4056unsigned __convert_to_integral(unsigned __val) { return __val; }
4057
4058inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4059long __convert_to_integral(long __val) { return __val; }
4060
4061inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4062unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4063
4064inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4065long long __convert_to_integral(long long __val) { return __val; }
4066
4067inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4068unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4069
4070template<typename _Fp>
4071inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4072typename enable_if<is_floating_point<_Fp>::value, long long>::type
4073 __convert_to_integral(_Fp __val) { return __val; }
4074
4075#ifndef _LIBCPP_HAS_NO_INT128
4076inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4077__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4078
4079inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4080__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4081#endif
4082
4083template <class _Tp>
4084inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4085typename __sfinae_underlying_type<_Tp>::__promoted_type
4086__convert_to_integral(_Tp __val) { return __val; }
4087
4088// is_scoped_enum [meta.unary.prop]
4089
4090#if _LIBCPP_STD_VER > 20
4091template <class _Tp, bool = is_enum_v<_Tp> >
4092struct __is_scoped_enum_helper : false_type {};
4093
4094template <class _Tp>
4095struct __is_scoped_enum_helper<_Tp, true>
4096    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
4097
4098template <class _Tp>
4099struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
4100    : public __is_scoped_enum_helper<_Tp> {};
4101
4102template <class _Tp>
4103inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
4104#endif
4105
4106#if _LIBCPP_STD_VER > 14
4107
4108template <class... _Args>
4109struct conjunction : _And<_Args...> {};
4110template<class... _Args>
4111inline constexpr bool conjunction_v = conjunction<_Args...>::value;
4112
4113template <class... _Args>
4114struct disjunction : _Or<_Args...> {};
4115template<class... _Args>
4116inline constexpr bool disjunction_v = disjunction<_Args...>::value;
4117
4118template <class _Tp>
4119struct negation : _Not<_Tp> {};
4120template<class _Tp>
4121inline constexpr bool negation_v = negation<_Tp>::value;
4122#endif // _LIBCPP_STD_VER > 14
4123
4124// These traits are used in __tree and __hash_table
4125struct __extract_key_fail_tag {};
4126struct __extract_key_self_tag {};
4127struct __extract_key_first_tag {};
4128
4129template <class _ValTy, class _Key,
4130          class _RawValTy = typename __unconstref<_ValTy>::type>
4131struct __can_extract_key
4132    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4133                  __extract_key_fail_tag>::type {};
4134
4135template <class _Pair, class _Key, class _First, class _Second>
4136struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
4137    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4138                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4139
4140// __can_extract_map_key uses true_type/false_type instead of the tags.
4141// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4142// and _ValTy == _Key.
4143template <class _ValTy, class _Key, class _ContainerValueTy,
4144          class _RawValTy = typename __unconstref<_ValTy>::type>
4145struct __can_extract_map_key
4146    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4147
4148// This specialization returns __extract_key_fail_tag for non-map containers
4149// because _Key == _ContainerValueTy
4150template <class _ValTy, class _Key, class _RawValTy>
4151struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4152    : false_type {};
4153
4154#if _LIBCPP_STD_VER > 17
4155_LIBCPP_INLINE_VISIBILITY
4156inline constexpr bool is_constant_evaluated() noexcept {
4157  return __builtin_is_constant_evaluated();
4158}
4159#endif
4160
4161inline _LIBCPP_CONSTEXPR
4162bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4163
4164template <class _CharT>
4165using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4166
4167template<class _Tp>
4168using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
4169
4170#if _LIBCPP_STD_VER > 17
4171template<bool _Const, class _Tp>
4172using __maybe_const = conditional_t<_Const, const _Tp, _Tp>;
4173#endif // _LIBCPP_STD_VER > 17
4174
4175_LIBCPP_END_NAMESPACE_STD
4176
4177#endif // _LIBCPP_TYPE_TRAITS
4178