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
458typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
459typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
460
461template <bool _Val>
462using _BoolConstant _LIBCPP_NODEBUG_TYPE = integral_constant<bool, _Val>;
463
464template <bool> struct _MetaBase;
465template <>
466struct _MetaBase<true> {
467  template <class _Tp, class _Up>
468  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Tp;
469  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
470  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _FirstFn<_Args...>;
471  template <class _First, class...>
472  using _FirstImpl _LIBCPP_NODEBUG_TYPE = _First;
473  template <class, class _Second, class...>
474  using _SecondImpl _LIBCPP_NODEBUG_TYPE = _Second;
475  template <class _Tp = void>
476  using _EnableIfImpl _LIBCPP_NODEBUG_TYPE = _Tp;
477  template <class _Result, class _First, class ..._Rest>
478  using _OrImpl _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
479};
480
481template <>
482struct _MetaBase<false> {
483  template <class _Tp, class _Up>
484  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Up;
485  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
486  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _SecondFn<_Args...>;
487  template <class _Result, class ...>
488  using _OrImpl _LIBCPP_NODEBUG_TYPE = _Result;
489};
490template <bool _Cond, class _Ret = void>
491using _EnableIf _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _EnableIfImpl<_Ret>;
492template <bool _Cond, class _IfRes, class _ElseRes>
493using _If _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
494template <class ..._Rest>
495using _Or _LIBCPP_NODEBUG_TYPE = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
496template <class _Pred>
497struct _Not : _BoolConstant<!_Pred::value> {};
498template <class ..._Args>
499using _FirstType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
500template <class ..._Args>
501using _SecondType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
502
503template <class ...> using __expand_to_true = true_type;
504template <class ..._Pred>
505__expand_to_true<_EnableIf<_Pred::value>...> __and_helper(int);
506template <class ...>
507false_type __and_helper(...);
508template <class ..._Pred>
509using _And _LIBCPP_NODEBUG_TYPE = decltype(__and_helper<_Pred...>(0));
510
511template <template <class...> class _Func, class ..._Args>
512struct _Lazy : _Func<_Args...> {};
513
514// Member detector base
515
516template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
517true_type __sfinae_test_impl(int);
518template <template <class...> class, class ...>
519false_type __sfinae_test_impl(...);
520
521template <template <class ...> class _Templ, class ..._Args>
522using _IsValidExpansion _LIBCPP_NODEBUG_TYPE = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
523
524template <class>
525struct __void_t { typedef void type; };
526
527template <class _Tp>
528struct __identity { typedef _Tp type; };
529
530template <class _Tp>
531using __identity_t _LIBCPP_NODEBUG_TYPE = typename __identity<_Tp>::type;
532
533template <class _Tp, bool>
534struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
535
536
537template <bool _Bp, class _If, class _Then>
538    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
539template <class _If, class _Then>
540    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
541
542#if _LIBCPP_STD_VER > 11
543template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
544#endif
545
546template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
547template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
548
549#if _LIBCPP_STD_VER > 11
550template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
551#endif
552
553// is_same
554
555#if __has_keyword(__is_same)
556
557template <class _Tp, class _Up>
558struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
559
560#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
561template <class _Tp, class _Up>
562_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v = __is_same(_Tp, _Up);
563#endif
564
565#else
566
567template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
568template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
569
570#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
571template <class _Tp, class _Up>
572_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v
573    = is_same<_Tp, _Up>::value;
574#endif
575
576#endif // __is_same
577
578template <class _Tp, class _Up>
579using _IsSame = _BoolConstant<
580#ifdef __clang__
581    __is_same(_Tp, _Up)
582#else
583    is_same<_Tp, _Up>::value
584#endif
585>;
586
587template <class _Tp, class _Up>
588using _IsNotSame = _BoolConstant<
589#ifdef __clang__
590    !__is_same(_Tp, _Up)
591#else
592    !is_same<_Tp, _Up>::value
593#endif
594>;
595
596
597template <class _Tp>
598using __test_for_primary_template = _EnableIf<
599    _IsSame<_Tp, typename _Tp::__primary_template>::value
600  >;
601template <class _Tp>
602using __is_primary_template = _IsValidExpansion<
603    __test_for_primary_template, _Tp
604  >;
605
606struct __two {char __lx[2];};
607
608// helper class:
609
610// is_const
611
612#if __has_keyword(__is_const)
613
614template <class _Tp>
615struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
616
617#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
618template <class _Tp>
619_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v = __is_const(_Tp);
620#endif
621
622#else
623
624template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
625template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
626
627#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
628template <class _Tp>
629_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v
630    = is_const<_Tp>::value;
631#endif
632
633#endif // __has_keyword(__is_const)
634
635// is_volatile
636
637#if __has_keyword(__is_volatile)
638
639template <class _Tp>
640struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
641
642#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
643template <class _Tp>
644_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v = __is_volatile(_Tp);
645#endif
646
647#else
648
649template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
650template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
651
652#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
653template <class _Tp>
654_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v
655    = is_volatile<_Tp>::value;
656#endif
657
658#endif // __has_keyword(__is_volatile)
659
660// remove_const
661
662#if __has_keyword(__remove_const)
663
664template <class _Tp>
665struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
666
667#if _LIBCPP_STD_VER > 11
668template <class _Tp> using remove_const_t = __remove_const(_Tp);
669#endif
670
671#else
672
673template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
674template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
675#if _LIBCPP_STD_VER > 11
676template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
677#endif
678
679#endif // __has_keyword(__remove_const)
680
681// remove_volatile
682
683#if __has_keyword(__remove_volatile)
684
685template <class _Tp>
686struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
687
688#if _LIBCPP_STD_VER > 11
689template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
690#endif
691
692#else
693
694template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
695template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
696#if _LIBCPP_STD_VER > 11
697template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
698#endif
699
700#endif // __has_keyword(__remove_volatile)
701
702// remove_cv
703
704#if __has_keyword(__remove_cv)
705
706template <class _Tp>
707struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
708
709#if _LIBCPP_STD_VER > 11
710template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
711#endif
712
713#else
714
715template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
716{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
717#if _LIBCPP_STD_VER > 11
718template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
719#endif
720
721#endif // __has_keyword(__remove_cv)
722
723// is_void
724
725#if __has_keyword(__is_void)
726
727template <class _Tp>
728struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
729
730#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
731template <class _Tp>
732_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v = __is_void(_Tp);
733#endif
734
735#else
736
737template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
738    : public is_same<typename remove_cv<_Tp>::type, void> {};
739
740#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
741template <class _Tp>
742_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v
743    = is_void<_Tp>::value;
744#endif
745
746#endif // __has_keyword(__is_void)
747
748// __is_nullptr_t
749
750template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
751template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
752
753template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
754    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
755
756#if _LIBCPP_STD_VER > 11
757template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
758    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
759
760#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
761template <class _Tp>
762_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_null_pointer_v
763    = is_null_pointer<_Tp>::value;
764#endif
765#endif // _LIBCPP_STD_VER > 11
766
767// is_integral
768
769#if __has_keyword(__is_integral)
770
771template <class _Tp>
772struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
773
774#if _LIBCPP_STD_VER > 14
775template <class _Tp>
776_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v = __is_integral(_Tp);
777#endif
778
779#else
780
781template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
782    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
783
784#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
785template <class _Tp>
786_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v
787    = is_integral<_Tp>::value;
788#endif
789
790#endif // __has_keyword(__is_integral)
791
792// __libcpp_is_signed_integer, __libcpp_is_unsigned_integer
793
794// [basic.fundamental] defines five standard signed integer types;
795// __int128_t is an extended signed integer type.
796// The signed and unsigned integer types, plus bool and the
797// five types with "char" in their name, compose the "integral" types.
798
799template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
800template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
801template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
802template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
803template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
804template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
805#ifndef _LIBCPP_HAS_NO_INT128
806template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
807#endif
808
809template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
810template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
811template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
812template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
813template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
814template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
815#ifndef _LIBCPP_HAS_NO_INT128
816template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
817#endif
818
819// is_floating_point
820
821template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
822template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
823template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
824template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
825
826template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
827    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
828
829#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
830template <class _Tp>
831_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_floating_point_v
832    = is_floating_point<_Tp>::value;
833#endif
834
835// is_array
836
837#if __has_keyword(__is_array)
838
839template <class _Tp>
840struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
841
842#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
843template <class _Tp>
844_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v = __is_array(_Tp);
845#endif
846
847#else
848
849template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
850    : public false_type {};
851template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
852    : public true_type {};
853template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
854    : public true_type {};
855
856#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
857template <class _Tp>
858_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v
859    = is_array<_Tp>::value;
860#endif
861
862#endif // __has_keyword(__is_array)
863
864// is_pointer
865
866// Before Clang 11 / AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
867#if __has_keyword(__is_pointer) &&                                             \
868    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1100) &&               \
869    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
870
871template<class _Tp>
872struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
873
874#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
875template <class _Tp>
876_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v = __is_pointer(_Tp);
877#endif
878
879#else // __has_keyword(__is_pointer)
880
881template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
882template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
883
884template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
885#if defined(_LIBCPP_HAS_OBJC_ARC)
886template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
887template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
888template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
889template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
890#endif
891
892template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
893    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
894
895#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
896template <class _Tp>
897_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v
898    = is_pointer<_Tp>::value;
899#endif
900
901#endif // __has_keyword(__is_pointer)
902
903// is_reference
904
905#if __has_keyword(__is_lvalue_reference) && \
906    __has_keyword(__is_rvalue_reference) && \
907    __has_keyword(__is_reference)
908
909template<class _Tp>
910struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
911
912template<class _Tp>
913struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
914
915template<class _Tp>
916struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
917
918#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
919template <class _Tp>
920_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v = __is_reference(_Tp);
921
922template <class _Tp>
923_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
924
925template <class _Tp>
926_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
927#endif
928
929#else // __has_keyword(__is_lvalue_reference) && etc...
930
931template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
932template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
933
934template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
935template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
936
937template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
938template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
939template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
940
941#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
942template <class _Tp>
943_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v
944    = is_reference<_Tp>::value;
945
946template <class _Tp>
947_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v
948    = is_lvalue_reference<_Tp>::value;
949
950template <class _Tp>
951_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v
952    = is_rvalue_reference<_Tp>::value;
953#endif
954
955#endif // __has_keyword(__is_lvalue_reference) && etc...
956
957// is_union
958
959#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
960
961template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
962    : public integral_constant<bool, __is_union(_Tp)> {};
963
964#else
965
966template <class _Tp> struct __libcpp_union : public false_type {};
967template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
968    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
969
970#endif
971
972#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
973template <class _Tp>
974_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_union_v
975    = is_union<_Tp>::value;
976#endif
977
978// is_class
979
980#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
981
982template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
983    : public integral_constant<bool, __is_class(_Tp)> {};
984
985#else
986
987namespace __is_class_imp
988{
989template <class _Tp> char  __test(int _Tp::*);
990template <class _Tp> __two __test(...);
991}
992
993template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
994    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
995
996#endif
997
998#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
999template <class _Tp>
1000_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_class_v
1001    = is_class<_Tp>::value;
1002#endif
1003
1004// is_function
1005
1006template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
1007    : public _BoolConstant<
1008#ifdef __clang__
1009    __is_function(_Tp)
1010#else
1011 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
1012#endif
1013    > {};
1014
1015
1016#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1017template <class _Tp>
1018_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_function_v
1019    = is_function<_Tp>::value;
1020#endif
1021
1022template <class _Tp> struct __libcpp_is_member_pointer {
1023  enum {
1024    __is_member = false,
1025    __is_func = false,
1026    __is_obj = false
1027  };
1028};
1029template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
1030  enum {
1031    __is_member = true,
1032    __is_func = is_function<_Tp>::value,
1033    __is_obj = !__is_func,
1034  };
1035};
1036
1037#if __has_keyword(__is_member_function_pointer)
1038
1039template<class _Tp>
1040struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1041    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1042
1043#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1044template <class _Tp>
1045_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1046    = __is_member_function_pointer(_Tp);
1047#endif
1048
1049#else // __has_keyword(__is_member_function_pointer)
1050
1051template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1052    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1053
1054#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1055template <class _Tp>
1056_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1057    = is_member_function_pointer<_Tp>::value;
1058#endif
1059
1060#endif // __has_keyword(__is_member_function_pointer)
1061
1062// is_member_pointer
1063
1064#if __has_keyword(__is_member_pointer)
1065
1066template<class _Tp>
1067struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
1068
1069#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1070template <class _Tp>
1071_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v = __is_member_pointer(_Tp);
1072#endif
1073
1074#else // __has_keyword(__is_member_pointer)
1075
1076template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1077 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1078
1079#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1080template <class _Tp>
1081_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v
1082    = is_member_pointer<_Tp>::value;
1083#endif
1084
1085#endif // __has_keyword(__is_member_pointer)
1086
1087// is_member_object_pointer
1088
1089#if __has_keyword(__is_member_object_pointer)
1090
1091template<class _Tp>
1092struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1093    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1094
1095#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1096template <class _Tp>
1097_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1098    = __is_member_object_pointer(_Tp);
1099#endif
1100
1101#else // __has_keyword(__is_member_object_pointer)
1102
1103template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1104    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1105
1106#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1107template <class _Tp>
1108_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1109    = is_member_object_pointer<_Tp>::value;
1110#endif
1111
1112#endif // __has_keyword(__is_member_object_pointer)
1113
1114// is_enum
1115
1116#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1117
1118template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1119    : public integral_constant<bool, __is_enum(_Tp)> {};
1120
1121#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1122template <class _Tp>
1123_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v = __is_enum(_Tp);
1124#endif
1125
1126#else
1127
1128template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1129    : public integral_constant<bool, !is_void<_Tp>::value             &&
1130                                     !is_integral<_Tp>::value         &&
1131                                     !is_floating_point<_Tp>::value   &&
1132                                     !is_array<_Tp>::value            &&
1133                                     !is_pointer<_Tp>::value          &&
1134                                     !is_reference<_Tp>::value        &&
1135                                     !is_member_pointer<_Tp>::value   &&
1136                                     !is_union<_Tp>::value            &&
1137                                     !is_class<_Tp>::value            &&
1138                                     !is_function<_Tp>::value         > {};
1139
1140#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1141template <class _Tp>
1142_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v
1143    = is_enum<_Tp>::value;
1144#endif
1145
1146#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1147
1148// is_arithmetic
1149
1150
1151template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1152    : public integral_constant<bool, is_integral<_Tp>::value      ||
1153                                     is_floating_point<_Tp>::value> {};
1154
1155#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1156template <class _Tp>
1157_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_arithmetic_v
1158    = is_arithmetic<_Tp>::value;
1159#endif
1160
1161// is_fundamental
1162
1163// Before Clang 10, __is_fundamental didn't work for nullptr_t.
1164// In C++03 nullptr_t is library-provided but must still count as "fundamental."
1165#if __has_keyword(__is_fundamental) &&                                         \
1166    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
1167    !defined(_LIBCPP_CXX03_LANG)
1168
1169template<class _Tp>
1170struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1171
1172#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1173template <class _Tp>
1174_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v = __is_fundamental(_Tp);
1175#endif
1176
1177#else // __has_keyword(__is_fundamental)
1178
1179template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1180    : public integral_constant<bool, is_void<_Tp>::value        ||
1181                                     __is_nullptr_t<_Tp>::value ||
1182                                     is_arithmetic<_Tp>::value> {};
1183
1184#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1185template <class _Tp>
1186_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v
1187    = is_fundamental<_Tp>::value;
1188#endif
1189
1190#endif // __has_keyword(__is_fundamental)
1191
1192// is_scalar
1193
1194// In C++03 nullptr_t is library-provided but must still count as "scalar."
1195#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1196
1197template<class _Tp>
1198struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1199
1200#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1201template <class _Tp>
1202_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v = __is_scalar(_Tp);
1203#endif
1204
1205#else // __has_keyword(__is_scalar)
1206
1207template <class _Tp> struct __is_block : false_type {};
1208#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1209template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1210#endif
1211
1212template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1213    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1214                                     is_member_pointer<_Tp>::value ||
1215                                     is_pointer<_Tp>::value        ||
1216                                     __is_nullptr_t<_Tp>::value    ||
1217                                     __is_block<_Tp>::value        ||
1218                                     is_enum<_Tp>::value           > {};
1219
1220template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1221
1222#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1223template <class _Tp>
1224_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v
1225    = is_scalar<_Tp>::value;
1226#endif
1227
1228#endif // __has_keyword(__is_scalar)
1229
1230// is_object
1231
1232#if __has_keyword(__is_object)
1233
1234template<class _Tp>
1235struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1236
1237#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1238template <class _Tp>
1239_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v = __is_object(_Tp);
1240#endif
1241
1242#else // __has_keyword(__is_object)
1243
1244template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1245    : public integral_constant<bool, is_scalar<_Tp>::value ||
1246                                     is_array<_Tp>::value  ||
1247                                     is_union<_Tp>::value  ||
1248                                     is_class<_Tp>::value  > {};
1249
1250#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1251template <class _Tp>
1252_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v
1253    = is_object<_Tp>::value;
1254#endif
1255
1256#endif // __has_keyword(__is_object)
1257
1258// is_compound
1259
1260// >= 11 because in C++03 nullptr isn't actually nullptr
1261#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1262
1263template<class _Tp>
1264struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1265
1266#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1267template <class _Tp>
1268_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v = __is_compound(_Tp);
1269#endif
1270
1271#else // __has_keyword(__is_compound)
1272
1273template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1274    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1275
1276#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1277template <class _Tp>
1278_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v
1279    = is_compound<_Tp>::value;
1280#endif
1281
1282#endif // __has_keyword(__is_compound)
1283
1284// __is_referenceable  [defns.referenceable]
1285
1286struct __is_referenceable_impl {
1287    template <class _Tp> static _Tp& __test(int);
1288    template <class _Tp> static __two __test(...);
1289};
1290
1291template <class _Tp>
1292struct __is_referenceable : integral_constant<bool,
1293    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1294
1295
1296// add_const
1297
1298template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1299  typedef _LIBCPP_NODEBUG_TYPE const _Tp type;
1300};
1301
1302#if _LIBCPP_STD_VER > 11
1303template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1304#endif
1305
1306// add_volatile
1307
1308template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1309  typedef _LIBCPP_NODEBUG_TYPE volatile _Tp type;
1310};
1311
1312#if _LIBCPP_STD_VER > 11
1313template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1314#endif
1315
1316// add_cv
1317template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1318  typedef _LIBCPP_NODEBUG_TYPE const volatile _Tp type;
1319};
1320
1321#if _LIBCPP_STD_VER > 11
1322template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1323#endif
1324
1325// remove_reference
1326
1327#if __has_keyword(__remove_reference)
1328
1329template<class _Tp>
1330struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1331
1332#else // __has_keyword(__remove_reference)
1333
1334template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1335template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1336template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1337
1338#if _LIBCPP_STD_VER > 11
1339template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1340#endif
1341
1342#endif // __has_keyword(__remove_reference)
1343
1344// add_lvalue_reference
1345
1346template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE _Tp  type; };
1347template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
1348
1349template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1350{typedef _LIBCPP_NODEBUG_TYPE typename  __add_lvalue_reference_impl<_Tp>::type type;};
1351
1352#if _LIBCPP_STD_VER > 11
1353template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1354#endif
1355
1356template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE  _Tp   type; };
1357template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE  _Tp&& type; };
1358
1359template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1360{typedef _LIBCPP_NODEBUG_TYPE  typename __add_rvalue_reference_impl<_Tp>::type type;};
1361
1362#if _LIBCPP_STD_VER > 11
1363template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1364#endif
1365
1366// Suppress deprecation notice for volatile-qualified return type resulting
1367// from volatile-qualified types _Tp.
1368_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1369template <class _Tp> _Tp&& __declval(int);
1370template <class _Tp> _Tp   __declval(long);
1371_LIBCPP_SUPPRESS_DEPRECATED_POP
1372
1373template <class _Tp>
1374decltype(__declval<_Tp>(0))
1375declval() _NOEXCEPT;
1376
1377// __uncvref
1378
1379template <class _Tp>
1380struct __uncvref  {
1381    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1382};
1383
1384template <class _Tp>
1385struct __unconstref {
1386    typedef _LIBCPP_NODEBUG_TYPE typename remove_const<typename remove_reference<_Tp>::type>::type type;
1387};
1388
1389#ifndef _LIBCPP_CXX03_LANG
1390template <class _Tp>
1391using __uncvref_t _LIBCPP_NODEBUG_TYPE = typename __uncvref<_Tp>::type;
1392#endif
1393
1394// __is_same_uncvref
1395
1396template <class _Tp, class _Up>
1397struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1398                                   typename __uncvref<_Up>::type> {};
1399
1400#if _LIBCPP_STD_VER > 17
1401// remove_cvref - same as __uncvref
1402template <class _Tp>
1403struct remove_cvref : public __uncvref<_Tp> {};
1404
1405template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1406#endif
1407
1408
1409struct __any
1410{
1411    __any(...);
1412};
1413
1414// remove_pointer
1415
1416template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1417template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1418template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1419template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1420template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1421
1422#if _LIBCPP_STD_VER > 11
1423template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1424#endif
1425
1426// add_pointer
1427
1428template <class _Tp,
1429        bool = __is_referenceable<_Tp>::value ||
1430                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1431struct __add_pointer_impl
1432    {typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type* type;};
1433template <class _Tp> struct __add_pointer_impl<_Tp, false>
1434    {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1435
1436template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1437    {typedef _LIBCPP_NODEBUG_TYPE typename __add_pointer_impl<_Tp>::type type;};
1438
1439#if _LIBCPP_STD_VER > 11
1440template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1441#endif
1442
1443// type_identity
1444#if _LIBCPP_STD_VER > 17
1445template<class _Tp> struct type_identity { typedef _Tp type; };
1446template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1447#endif
1448
1449// is_signed
1450
1451// Before Clang 10, __is_signed didn't work for floating-point types or enums.
1452#if __has_keyword(__is_signed) &&                                              \
1453    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000)
1454
1455template<class _Tp>
1456struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1457
1458#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1459template <class _Tp>
1460_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v = __is_signed(_Tp);
1461#endif
1462
1463#else // __has_keyword(__is_signed)
1464
1465template <class _Tp, bool = is_integral<_Tp>::value>
1466struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1467
1468template <class _Tp>
1469struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1470
1471template <class _Tp, bool = is_arithmetic<_Tp>::value>
1472struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1473
1474template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1475
1476template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1477
1478#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1479template <class _Tp>
1480_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v
1481    = is_signed<_Tp>::value;
1482#endif
1483
1484#endif // __has_keyword(__is_signed)
1485
1486// is_unsigned
1487
1488// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
1489// No currently-released version of AppleClang contains the fixed intrinsic.
1490#if __has_keyword(__is_unsigned) &&                                            \
1491    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
1492    !defined(_LIBCPP_APPLE_CLANG_VER)
1493
1494template<class _Tp>
1495struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
1496
1497#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1498template <class _Tp>
1499_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v = __is_unsigned(_Tp);
1500#endif
1501
1502#else // __has_keyword(__is_unsigned)
1503
1504template <class _Tp, bool = is_integral<_Tp>::value>
1505struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1506
1507template <class _Tp>
1508struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1509
1510template <class _Tp, bool = is_arithmetic<_Tp>::value>
1511struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1512
1513template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1514
1515template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1516
1517#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1518template <class _Tp>
1519_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v
1520    = is_unsigned<_Tp>::value;
1521#endif
1522
1523#endif // __has_keyword(__is_unsigned)
1524
1525// rank
1526
1527template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1528    : public integral_constant<size_t, 0> {};
1529template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1530    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1531template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1532    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1533
1534#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1535template <class _Tp>
1536_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t rank_v
1537    = rank<_Tp>::value;
1538#endif
1539
1540// extent
1541
1542#if __has_keyword(__array_extent)
1543
1544template<class _Tp, size_t _Dim = 0>
1545struct _LIBCPP_TEMPLATE_VIS extent
1546    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1547
1548#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1549template <class _Tp, unsigned _Ip = 0>
1550_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v = __array_extent(_Tp, _Ip);
1551#endif
1552
1553#else // __has_keyword(__array_extent)
1554
1555template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1556    : public integral_constant<size_t, 0> {};
1557template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1558    : public integral_constant<size_t, 0> {};
1559template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1560    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1561template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1562    : public integral_constant<size_t, _Np> {};
1563template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1564    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1565
1566#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1567template <class _Tp, unsigned _Ip = 0>
1568_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v
1569    = extent<_Tp, _Ip>::value;
1570#endif
1571
1572#endif // __has_keyword(__array_extent)
1573
1574// remove_extent
1575
1576template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1577    {typedef _Tp type;};
1578template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1579    {typedef _Tp type;};
1580template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1581    {typedef _Tp type;};
1582
1583#if _LIBCPP_STD_VER > 11
1584template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1585#endif
1586
1587// remove_all_extents
1588
1589template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1590    {typedef _Tp type;};
1591template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1592    {typedef typename remove_all_extents<_Tp>::type type;};
1593template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1594    {typedef typename remove_all_extents<_Tp>::type type;};
1595
1596#if _LIBCPP_STD_VER > 11
1597template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1598#endif
1599
1600#if _LIBCPP_STD_VER > 17
1601// is_bounded_array
1602
1603template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1604template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1605
1606template <class _Tp>
1607_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1608bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1609
1610// is_unbounded_array
1611
1612template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1613template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1614
1615template <class _Tp>
1616_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1617bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1618#endif
1619
1620// decay
1621
1622template <class _Up, bool>
1623struct __decay {
1624    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<_Up>::type type;
1625};
1626
1627template <class _Up>
1628struct __decay<_Up, true> {
1629public:
1630    typedef _LIBCPP_NODEBUG_TYPE typename conditional
1631                     <
1632                         is_array<_Up>::value,
1633                         typename remove_extent<_Up>::type*,
1634                         typename conditional
1635                         <
1636                              is_function<_Up>::value,
1637                              typename add_pointer<_Up>::type,
1638                              typename remove_cv<_Up>::type
1639                         >::type
1640                     >::type type;
1641};
1642
1643template <class _Tp>
1644struct _LIBCPP_TEMPLATE_VIS decay
1645{
1646private:
1647    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
1648public:
1649    typedef _LIBCPP_NODEBUG_TYPE typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1650};
1651
1652#if _LIBCPP_STD_VER > 11
1653template <class _Tp> using decay_t = typename decay<_Tp>::type;
1654#endif
1655
1656// is_abstract
1657
1658template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1659    : public integral_constant<bool, __is_abstract(_Tp)> {};
1660
1661#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1662template <class _Tp>
1663_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_abstract_v
1664    = is_abstract<_Tp>::value;
1665#endif
1666
1667// is_final
1668
1669template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1670__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1671
1672#if _LIBCPP_STD_VER > 11
1673template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1674is_final : public integral_constant<bool, __is_final(_Tp)> {};
1675#endif
1676
1677#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1678template <class _Tp>
1679_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_final_v
1680    = is_final<_Tp>::value;
1681#endif
1682
1683// is_aggregate
1684#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1685
1686template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1687is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1688
1689#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1690template <class _Tp>
1691_LIBCPP_INLINE_VAR constexpr bool is_aggregate_v
1692    = is_aggregate<_Tp>::value;
1693#endif
1694
1695#endif // _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1696
1697// is_base_of
1698
1699template <class _Bp, class _Dp>
1700struct _LIBCPP_TEMPLATE_VIS is_base_of
1701    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1702
1703#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1704template <class _Bp, class _Dp>
1705_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_base_of_v
1706    = is_base_of<_Bp, _Dp>::value;
1707#endif
1708
1709// __is_core_convertible
1710
1711// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
1712// We can't test for that, but we can test implicit convertibility by passing it
1713// to a function. Notice that __is_core_convertible<void,void> is false,
1714// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.
1715
1716template <class _Tp, class _Up, class = void>
1717struct __is_core_convertible : public false_type {};
1718
1719template <class _Tp, class _Up>
1720struct __is_core_convertible<_Tp, _Up, decltype(
1721    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
1722)> : public true_type {};
1723
1724// is_convertible
1725
1726#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1727
1728template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1729    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1730
1731#else  // __has_feature(is_convertible_to)
1732
1733namespace __is_convertible_imp
1734{
1735template <class _Tp> void  __test_convert(_Tp);
1736
1737template <class _From, class _To, class = void>
1738struct __is_convertible_test : public false_type {};
1739
1740template <class _From, class _To>
1741struct __is_convertible_test<_From, _To,
1742    decltype(__is_convertible_imp::__test_convert<_To>(declval<_From>()))> : public true_type
1743{};
1744
1745template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1746                     bool _IsFunction = is_function<_Tp>::value,
1747                     bool _IsVoid =     is_void<_Tp>::value>
1748                     struct __is_array_function_or_void                          {enum {value = 0};};
1749template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1750template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1751template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1752}
1753
1754template <class _Tp,
1755    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1756struct __is_convertible_check
1757{
1758    static const size_t __v = 0;
1759};
1760
1761template <class _Tp>
1762struct __is_convertible_check<_Tp, 0>
1763{
1764    static const size_t __v = sizeof(_Tp);
1765};
1766
1767template <class _T1, class _T2,
1768    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1769    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1770struct __is_convertible
1771    : public integral_constant<bool,
1772        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1773    >
1774{};
1775
1776template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1777template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1778template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1779template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1780
1781template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1782template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1783template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1784template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1785
1786template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1787template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1788template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1789template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1790
1791template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1792    : public __is_convertible<_T1, _T2>
1793{
1794    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1795    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1796};
1797
1798#endif // __has_feature(is_convertible_to)
1799
1800#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1801template <class _From, class _To>
1802_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_convertible_v
1803    = is_convertible<_From, _To>::value;
1804#endif
1805
1806// is_nothrow_convertible
1807
1808#if _LIBCPP_STD_VER > 17
1809
1810template <typename _Tp>
1811static void __test_noexcept(_Tp) noexcept;
1812
1813template<typename _Fm, typename _To>
1814static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
1815__is_nothrow_convertible_test();
1816
1817template <typename _Fm, typename _To>
1818struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1819{ };
1820
1821template <typename _Fm, typename _To>
1822struct is_nothrow_convertible : _Or<
1823    _And<is_void<_To>, is_void<_Fm>>,
1824    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1825>::type { };
1826
1827template <typename _Fm, typename _To>
1828inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1829
1830#endif // _LIBCPP_STD_VER > 17
1831
1832// is_empty
1833
1834#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1835
1836template <class _Tp>
1837struct _LIBCPP_TEMPLATE_VIS is_empty
1838    : public integral_constant<bool, __is_empty(_Tp)> {};
1839
1840#else  // __has_feature(is_empty)
1841
1842template <class _Tp>
1843struct __is_empty1
1844    : public _Tp
1845{
1846    double __lx;
1847};
1848
1849struct __is_empty2
1850{
1851    double __lx;
1852};
1853
1854template <class _Tp, bool = is_class<_Tp>::value>
1855struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1856
1857template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1858
1859template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1860
1861#endif // __has_feature(is_empty)
1862
1863#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1864template <class _Tp>
1865_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_empty_v
1866    = is_empty<_Tp>::value;
1867#endif
1868
1869// is_polymorphic
1870
1871#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1872
1873template <class _Tp>
1874struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1875    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1876
1877#else
1878
1879template<typename _Tp> char &__is_polymorphic_impl(
1880    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1881                       int>::type);
1882template<typename _Tp> __two &__is_polymorphic_impl(...);
1883
1884template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1885    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1886
1887#endif // __has_feature(is_polymorphic)
1888
1889#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1890template <class _Tp>
1891_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_polymorphic_v
1892    = is_polymorphic<_Tp>::value;
1893#endif
1894
1895// has_virtual_destructor
1896
1897#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1898
1899template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1900    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1901
1902#else
1903
1904template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1905    : public false_type {};
1906
1907#endif
1908
1909#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1910template <class _Tp>
1911_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_virtual_destructor_v
1912    = has_virtual_destructor<_Tp>::value;
1913#endif
1914
1915// has_unique_object_representations
1916
1917#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_UNIQUE_OBJECT_REPRESENTATIONS)
1918
1919template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1920    : public integral_constant<bool,
1921       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1922
1923#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1924template <class _Tp>
1925_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_unique_object_representations_v
1926    = has_unique_object_representations<_Tp>::value;
1927#endif
1928
1929#endif
1930
1931// alignment_of
1932
1933template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1934    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1935
1936#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1937template <class _Tp>
1938_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t alignment_of_v
1939    = alignment_of<_Tp>::value;
1940#endif
1941
1942// aligned_storage
1943
1944template <class _Hp, class _Tp>
1945struct __type_list
1946{
1947    typedef _Hp _Head;
1948    typedef _Tp _Tail;
1949};
1950
1951struct __nat
1952{
1953#ifndef _LIBCPP_CXX03_LANG
1954    __nat() = delete;
1955    __nat(const __nat&) = delete;
1956    __nat& operator=(const __nat&) = delete;
1957    ~__nat() = delete;
1958#endif
1959};
1960
1961template <class _Tp>
1962struct __align_type
1963{
1964    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1965    typedef _Tp type;
1966};
1967
1968struct __struct_double {long double __lx;};
1969struct __struct_double4 {double __lx[4];};
1970
1971typedef
1972    __type_list<__align_type<unsigned char>,
1973    __type_list<__align_type<unsigned short>,
1974    __type_list<__align_type<unsigned int>,
1975    __type_list<__align_type<unsigned long>,
1976    __type_list<__align_type<unsigned long long>,
1977    __type_list<__align_type<double>,
1978    __type_list<__align_type<long double>,
1979    __type_list<__align_type<__struct_double>,
1980    __type_list<__align_type<__struct_double4>,
1981    __type_list<__align_type<int*>,
1982    __nat
1983    > > > > > > > > > > __all_types;
1984
1985template <size_t _Align>
1986struct _ALIGNAS(_Align) __fallback_overaligned {};
1987
1988template <class _TL, size_t _Align> struct __find_pod;
1989
1990template <class _Hp, size_t _Align>
1991struct __find_pod<__type_list<_Hp, __nat>, _Align>
1992{
1993    typedef typename conditional<
1994                             _Align == _Hp::value,
1995                             typename _Hp::type,
1996                             __fallback_overaligned<_Align>
1997                         >::type type;
1998};
1999
2000template <class _Hp, class _Tp, size_t _Align>
2001struct __find_pod<__type_list<_Hp, _Tp>, _Align>
2002{
2003    typedef typename conditional<
2004                             _Align == _Hp::value,
2005                             typename _Hp::type,
2006                             typename __find_pod<_Tp, _Align>::type
2007                         >::type type;
2008};
2009
2010template <class _TL, size_t _Len> struct __find_max_align;
2011
2012template <class _Hp, size_t _Len>
2013struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
2014
2015template <size_t _Len, size_t _A1, size_t _A2>
2016struct __select_align
2017{
2018private:
2019    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
2020    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
2021public:
2022    static const size_t value = _Len < __max ? __min : __max;
2023};
2024
2025template <class _Hp, class _Tp, size_t _Len>
2026struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
2027    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
2028
2029template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2030struct _LIBCPP_TEMPLATE_VIS aligned_storage
2031{
2032    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
2033    union type
2034    {
2035        _Aligner __align;
2036        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
2037    };
2038};
2039
2040#if _LIBCPP_STD_VER > 11
2041template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2042    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
2043#endif
2044
2045#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
2046template <size_t _Len>\
2047struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
2048{\
2049    struct _ALIGNAS(n) type\
2050    {\
2051        unsigned char __lx[(_Len + n - 1)/n * n];\
2052    };\
2053}
2054
2055_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2056_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2057_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2058_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2059_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2060_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2061_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2062_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2063_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2064_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2065_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2066_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2067_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2068_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2069// PE/COFF does not support alignment beyond 8192 (=0x2000)
2070#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2071_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2072#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2073
2074#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2075
2076
2077// aligned_union
2078
2079template <size_t _I0, size_t ..._In>
2080struct __static_max;
2081
2082template <size_t _I0>
2083struct __static_max<_I0>
2084{
2085    static const size_t value = _I0;
2086};
2087
2088template <size_t _I0, size_t _I1, size_t ..._In>
2089struct __static_max<_I0, _I1, _In...>
2090{
2091    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2092                                             __static_max<_I1, _In...>::value;
2093};
2094
2095template <size_t _Len, class _Type0, class ..._Types>
2096struct aligned_union
2097{
2098    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2099                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2100    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2101                                             sizeof(_Types)...>::value;
2102    typedef typename aligned_storage<__len, alignment_value>::type type;
2103};
2104
2105#if _LIBCPP_STD_VER > 11
2106template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2107#endif
2108
2109template <class _Tp>
2110struct __numeric_type
2111{
2112   static void __test(...);
2113   static float __test(float);
2114   static double __test(char);
2115   static double __test(int);
2116   static double __test(unsigned);
2117   static double __test(long);
2118   static double __test(unsigned long);
2119   static double __test(long long);
2120   static double __test(unsigned long long);
2121   static double __test(double);
2122   static long double __test(long double);
2123
2124   typedef decltype(__test(declval<_Tp>())) type;
2125   static const bool value = _IsNotSame<type, void>::value;
2126};
2127
2128template <>
2129struct __numeric_type<void>
2130{
2131   static const bool value = true;
2132};
2133
2134// __promote
2135
2136template <class _A1, class _A2 = void, class _A3 = void,
2137          bool = __numeric_type<_A1>::value &&
2138                 __numeric_type<_A2>::value &&
2139                 __numeric_type<_A3>::value>
2140class __promote_imp
2141{
2142public:
2143    static const bool value = false;
2144};
2145
2146template <class _A1, class _A2, class _A3>
2147class __promote_imp<_A1, _A2, _A3, true>
2148{
2149private:
2150    typedef typename __promote_imp<_A1>::type __type1;
2151    typedef typename __promote_imp<_A2>::type __type2;
2152    typedef typename __promote_imp<_A3>::type __type3;
2153public:
2154    typedef decltype(__type1() + __type2() + __type3()) type;
2155    static const bool value = true;
2156};
2157
2158template <class _A1, class _A2>
2159class __promote_imp<_A1, _A2, void, true>
2160{
2161private:
2162    typedef typename __promote_imp<_A1>::type __type1;
2163    typedef typename __promote_imp<_A2>::type __type2;
2164public:
2165    typedef decltype(__type1() + __type2()) type;
2166    static const bool value = true;
2167};
2168
2169template <class _A1>
2170class __promote_imp<_A1, void, void, true>
2171{
2172public:
2173    typedef typename __numeric_type<_A1>::type type;
2174    static const bool value = true;
2175};
2176
2177template <class _A1, class _A2 = void, class _A3 = void>
2178class __promote : public __promote_imp<_A1, _A2, _A3> {};
2179
2180// make_signed / make_unsigned
2181
2182typedef
2183    __type_list<signed char,
2184    __type_list<signed short,
2185    __type_list<signed int,
2186    __type_list<signed long,
2187    __type_list<signed long long,
2188#ifndef _LIBCPP_HAS_NO_INT128
2189    __type_list<__int128_t,
2190#endif
2191    __nat
2192#ifndef _LIBCPP_HAS_NO_INT128
2193    >
2194#endif
2195    > > > > > __signed_types;
2196
2197typedef
2198    __type_list<unsigned char,
2199    __type_list<unsigned short,
2200    __type_list<unsigned int,
2201    __type_list<unsigned long,
2202    __type_list<unsigned long long,
2203#ifndef _LIBCPP_HAS_NO_INT128
2204    __type_list<__uint128_t,
2205#endif
2206    __nat
2207#ifndef _LIBCPP_HAS_NO_INT128
2208    >
2209#endif
2210    > > > > > __unsigned_types;
2211
2212template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2213
2214template <class _Hp, class _Tp, size_t _Size>
2215struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2216{
2217    typedef _LIBCPP_NODEBUG_TYPE _Hp type;
2218};
2219
2220template <class _Hp, class _Tp, size_t _Size>
2221struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2222{
2223    typedef _LIBCPP_NODEBUG_TYPE typename __find_first<_Tp, _Size>::type type;
2224};
2225
2226template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2227                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2228struct __apply_cv
2229{
2230    typedef _LIBCPP_NODEBUG_TYPE _Up type;
2231};
2232
2233template <class _Tp, class _Up>
2234struct __apply_cv<_Tp, _Up, true, false>
2235{
2236    typedef _LIBCPP_NODEBUG_TYPE const _Up type;
2237};
2238
2239template <class _Tp, class _Up>
2240struct __apply_cv<_Tp, _Up, false, true>
2241{
2242    typedef volatile _Up type;
2243};
2244
2245template <class _Tp, class _Up>
2246struct __apply_cv<_Tp, _Up, true, true>
2247{
2248    typedef const volatile _Up type;
2249};
2250
2251template <class _Tp, class _Up>
2252struct __apply_cv<_Tp&, _Up, false, false>
2253{
2254    typedef _Up& type;
2255};
2256
2257template <class _Tp, class _Up>
2258struct __apply_cv<_Tp&, _Up, true, false>
2259{
2260    typedef const _Up& type;
2261};
2262
2263template <class _Tp, class _Up>
2264struct __apply_cv<_Tp&, _Up, false, true>
2265{
2266    typedef volatile _Up& type;
2267};
2268
2269template <class _Tp, class _Up>
2270struct __apply_cv<_Tp&, _Up, true, true>
2271{
2272    typedef const volatile _Up& type;
2273};
2274
2275template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2276struct __make_signed {};
2277
2278template <class _Tp>
2279struct __make_signed<_Tp, true>
2280{
2281    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2282};
2283
2284template <> struct __make_signed<bool,               true> {};
2285template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2286template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2287template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2288template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2289template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2290template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2291template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2292template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2293#ifndef _LIBCPP_HAS_NO_INT128
2294template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2295template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2296#endif
2297
2298template <class _Tp>
2299struct _LIBCPP_TEMPLATE_VIS make_signed
2300{
2301    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2302};
2303
2304#if _LIBCPP_STD_VER > 11
2305template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2306#endif
2307
2308template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2309struct __make_unsigned {};
2310
2311template <class _Tp>
2312struct __make_unsigned<_Tp, true>
2313{
2314    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2315};
2316
2317template <> struct __make_unsigned<bool,               true> {};
2318template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2319template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2320template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2321template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2322template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2323template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2324template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2325template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2326#ifndef _LIBCPP_HAS_NO_INT128
2327template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2328template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2329#endif
2330
2331template <class _Tp>
2332struct _LIBCPP_TEMPLATE_VIS make_unsigned
2333{
2334    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2335};
2336
2337#if _LIBCPP_STD_VER > 11
2338template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2339#endif
2340
2341#ifndef _LIBCPP_CXX03_LANG
2342template <class _Tp>
2343_LIBCPP_NODISCARD_ATTRIBUTE _LIBCPP_INLINE_VISIBILITY constexpr
2344typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
2345    return static_cast<typename make_unsigned<_Tp>::type>(__x);
2346}
2347#endif
2348
2349#if _LIBCPP_STD_VER > 14
2350template <class...> using void_t = void;
2351#endif
2352
2353#if _LIBCPP_STD_VER > 17
2354// Let COND_RES(X, Y) be:
2355template <class _Tp, class _Up>
2356using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
2357
2358template <class _Tp, class _Up, class = void>
2359struct __common_type3 {};
2360
2361// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
2362template <class _Tp, class _Up>
2363struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
2364{
2365    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
2366};
2367
2368template <class _Tp, class _Up, class = void>
2369struct __common_type2_imp : __common_type3<_Tp, _Up> {};
2370#else
2371template <class _Tp, class _Up, class = void>
2372struct __common_type2_imp {};
2373#endif
2374
2375// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
2376template <class _Tp, class _Up>
2377struct __common_type2_imp<_Tp, _Up,
2378                          typename __void_t<decltype(
2379                                            true ? declval<_Tp>() : declval<_Up>()
2380                                            )>::type>
2381{
2382  typedef _LIBCPP_NODEBUG_TYPE typename decay<decltype(
2383                         true ? declval<_Tp>() : declval<_Up>()
2384                         )>::type type;
2385};
2386
2387template <class, class = void>
2388struct __common_type_impl {};
2389
2390// Clang provides variadic templates in C++03 as an extension.
2391#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2392# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2393template <class... Tp>
2394struct __common_types;
2395template <class... _Tp>
2396struct _LIBCPP_TEMPLATE_VIS common_type;
2397#else
2398# define _LIBCPP_OPTIONAL_PACK(...)
2399struct __no_arg;
2400template <class _Tp, class _Up, class = __no_arg>
2401struct __common_types;
2402template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2403          class _Unused = __no_arg>
2404struct common_type {
2405  static_assert(sizeof(_Unused) == 0,
2406                "common_type accepts at most 3 arguments in C++03");
2407};
2408#endif // _LIBCPP_CXX03_LANG
2409
2410template <class _Tp, class _Up>
2411struct __common_type_impl<
2412    __common_types<_Tp, _Up>,
2413    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2414{
2415  typedef typename common_type<_Tp, _Up>::type type;
2416};
2417
2418template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2419struct __common_type_impl<
2420    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2421    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2422    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2423                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2424};
2425
2426// bullet 1 - sizeof...(Tp) == 0
2427
2428template <>
2429struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2430
2431// bullet 2 - sizeof...(Tp) == 1
2432
2433template <class _Tp>
2434struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2435    : public common_type<_Tp, _Tp> {};
2436
2437// bullet 3 - sizeof...(Tp) == 2
2438
2439// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
2440template <class _Tp, class _Up>
2441struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2442    : conditional<
2443        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2444        __common_type2_imp<_Tp, _Up>,
2445        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2446    >::type
2447{};
2448
2449// bullet 4 - sizeof...(Tp) > 2
2450
2451template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2452struct _LIBCPP_TEMPLATE_VIS
2453    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2454    : __common_type_impl<
2455          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2456
2457#undef _LIBCPP_OPTIONAL_PACK
2458
2459#if _LIBCPP_STD_VER > 11
2460template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2461#endif
2462
2463#if _LIBCPP_STD_VER > 11
2464// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
2465// top-level cv-qualifiers.
2466template <class _From, class _To>
2467struct __copy_cv
2468{
2469    using type = _To;
2470};
2471
2472template <class _From, class _To>
2473struct __copy_cv<const _From, _To>
2474{
2475    using type = add_const_t<_To>;
2476};
2477
2478template <class _From, class _To>
2479struct __copy_cv<volatile _From, _To>
2480{
2481    using type = add_volatile_t<_To>;
2482};
2483
2484template <class _From, class _To>
2485struct __copy_cv<const volatile _From, _To>
2486{
2487    using type = add_cv_t<_To>;
2488};
2489
2490template <class _From, class _To>
2491using __copy_cv_t = typename __copy_cv<_From, _To>::type;
2492
2493template <class _From, class _To>
2494struct __copy_cvref
2495{
2496    using type = __copy_cv_t<_From, _To>;
2497};
2498
2499template <class _From, class _To>
2500struct __copy_cvref<_From&, _To>
2501{
2502    using type = add_lvalue_reference_t<__copy_cv_t<_From, _To>>;
2503};
2504
2505template <class _From, class _To>
2506struct __copy_cvref<_From&&, _To>
2507{
2508    using type = add_rvalue_reference_t<__copy_cv_t<_From, _To>>;
2509};
2510
2511template <class _From, class _To>
2512using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
2513
2514#endif // _LIBCPP_STD_VER > 11
2515
2516// common_reference
2517#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2518// Let COND_RES(X, Y) be:
2519template <class _Xp, class _Yp>
2520using __cond_res =
2521    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
2522
2523// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
2524// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
2525// `U`.
2526// [Note: `XREF(A)` is `__xref<A>::template __apply`]
2527template <class _Tp>
2528struct __xref {
2529  template<class _Up>
2530  using __apply = __copy_cvref_t<_Tp, _Up>;
2531};
2532
2533// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
2534// and let COMMON-REF(A, B) be:
2535template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
2536struct __common_ref;
2537
2538template<class _Xp, class _Yp>
2539using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
2540
2541template<class _Xp, class _Yp>
2542using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
2543
2544
2545//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
2546//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
2547template<class _Ap, class _Bp, class _Xp, class _Yp>
2548requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
2549struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
2550{
2551    using __type = __cv_cond_res<_Xp, _Yp>;
2552};
2553
2554//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
2555template <class _Xp, class _Yp>
2556using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
2557
2558
2559//    .... If A and B are both rvalue reference types, C is well-formed, and
2560//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
2561template<class _Ap, class _Bp, class _Xp, class _Yp>
2562requires
2563  requires { typename __common_ref_C<_Xp, _Yp>; } &&
2564  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
2565  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
2566struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
2567{
2568    using __type = __common_ref_C<_Xp, _Yp>;
2569};
2570
2571//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
2572template <class _Tp, class _Up>
2573using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
2574
2575//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
2576//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
2577template<class _Ap, class _Bp, class _Xp, class _Yp>
2578requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
2579         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
2580struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
2581{
2582    using __type = __common_ref_D<_Xp, _Yp>;
2583};
2584
2585//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
2586//    COMMON-REF(A, B) is COMMON-REF(B, A).
2587template<class _Ap, class _Bp, class _Xp, class _Yp>
2588struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
2589
2590//    Otherwise, COMMON-REF(A, B) is ill-formed.
2591template<class _Ap, class _Bp, class _Xp, class _Yp>
2592struct __common_ref {};
2593
2594// Note C: For the common_reference trait applied to a parameter pack [...]
2595
2596template <class...>
2597struct common_reference;
2598
2599template <class... _Types>
2600using common_reference_t = typename common_reference<_Types...>::type;
2601
2602// bullet 1 - sizeof...(T) == 0
2603template<>
2604struct common_reference<> {};
2605
2606// bullet 2 - sizeof...(T) == 1
2607template <class _Tp>
2608struct common_reference<_Tp>
2609{
2610    using type = _Tp;
2611};
2612
2613// bullet 3 - sizeof...(T) == 2
2614template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
2615template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
2616template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
2617
2618// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
2619// the member typedef `type` denotes that type.
2620template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
2621
2622template <class _Tp, class _Up>
2623requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
2624struct __common_reference_sub_bullet1<_Tp, _Up>
2625{
2626    using type = __common_ref_t<_Tp, _Up>;
2627};
2628
2629// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
2630// is well-formed, then the member typedef `type` denotes that type.
2631template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
2632
2633template <class _Tp, class _Up>
2634using __basic_common_reference_t = typename basic_common_reference<
2635    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
2636    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
2637
2638template <class _Tp, class _Up>
2639requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
2640struct __common_reference_sub_bullet2<_Tp, _Up>
2641{
2642    using type = __basic_common_reference_t<_Tp, _Up>;
2643};
2644
2645// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
2646// then the member typedef `type` denotes that type.
2647template <class _Tp, class _Up>
2648requires requires { typename __cond_res<_Tp, _Up>; }
2649struct __common_reference_sub_bullet3<_Tp, _Up>
2650{
2651    using type = __cond_res<_Tp, _Up>;
2652};
2653
2654
2655// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
2656//                    then the member typedef `type` denotes that type.
2657//                  - Otherwise, there shall be no member `type`.
2658template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
2659
2660// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
2661//            any, as `common_reference_t<C, Rest...>`.
2662template <class _Tp, class _Up, class _Vp, class... _Rest>
2663requires requires { typename common_reference_t<_Tp, _Up>; }
2664struct common_reference<_Tp, _Up, _Vp, _Rest...>
2665    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
2666{};
2667
2668// bullet 5 - Otherwise, there shall be no member `type`.
2669template <class...> struct common_reference {};
2670
2671#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2672
2673// is_assignable
2674
2675template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
2676
2677#if __has_keyword(__is_assignable)
2678
2679template<class _Tp, class _Up>
2680struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2681
2682#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2683template <class _Tp, class _Arg>
2684_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v = __is_assignable(_Tp, _Arg);
2685#endif
2686
2687#else // __has_keyword(__is_assignable)
2688
2689template <class _Tp, class _Arg>
2690typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
2691__is_assignable_test(int);
2692
2693template <class, class>
2694false_type __is_assignable_test(...);
2695
2696
2697template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2698struct __is_assignable_imp
2699    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2700
2701template <class _Tp, class _Arg>
2702struct __is_assignable_imp<_Tp, _Arg, true>
2703    : public false_type
2704{
2705};
2706
2707template <class _Tp, class _Arg>
2708struct is_assignable
2709    : public __is_assignable_imp<_Tp, _Arg> {};
2710
2711#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2712template <class _Tp, class _Arg>
2713_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v
2714    = is_assignable<_Tp, _Arg>::value;
2715#endif
2716
2717#endif // __has_keyword(__is_assignable)
2718
2719// is_copy_assignable
2720
2721template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2722    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2723                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2724
2725#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2726template <class _Tp>
2727_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_assignable_v
2728    = is_copy_assignable<_Tp>::value;
2729#endif
2730
2731// is_move_assignable
2732
2733template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2734    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2735                           typename add_rvalue_reference<_Tp>::type> {};
2736
2737#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2738template <class _Tp>
2739_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_assignable_v
2740    = is_move_assignable<_Tp>::value;
2741#endif
2742
2743// is_destructible
2744
2745#if __has_keyword(__is_destructible)
2746
2747template<class _Tp>
2748struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2749
2750#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2751template <class _Tp>
2752_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v = __is_destructible(_Tp);
2753#endif
2754
2755#else // __has_keyword(__is_destructible)
2756
2757//  if it's a reference, return true
2758//  if it's a function, return false
2759//  if it's   void,     return false
2760//  if it's an array of unknown bound, return false
2761//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
2762//    where _Up is remove_all_extents<_Tp>::type
2763
2764template <class>
2765struct __is_destructible_apply { typedef int type; };
2766
2767template <typename _Tp>
2768struct __is_destructor_wellformed {
2769    template <typename _Tp1>
2770    static char  __test (
2771        typename __is_destructible_apply<decltype(declval<_Tp1&>().~_Tp1())>::type
2772    );
2773
2774    template <typename _Tp1>
2775    static __two __test (...);
2776
2777    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2778};
2779
2780template <class _Tp, bool>
2781struct __destructible_imp;
2782
2783template <class _Tp>
2784struct __destructible_imp<_Tp, false>
2785   : public integral_constant<bool,
2786        __is_destructor_wellformed<typename remove_all_extents<_Tp>::type>::value> {};
2787
2788template <class _Tp>
2789struct __destructible_imp<_Tp, true>
2790    : public true_type {};
2791
2792template <class _Tp, bool>
2793struct __destructible_false;
2794
2795template <class _Tp>
2796struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, is_reference<_Tp>::value> {};
2797
2798template <class _Tp>
2799struct __destructible_false<_Tp, true> : public false_type {};
2800
2801template <class _Tp>
2802struct is_destructible
2803    : public __destructible_false<_Tp, is_function<_Tp>::value> {};
2804
2805template <class _Tp>
2806struct is_destructible<_Tp[]>
2807    : public false_type {};
2808
2809template <>
2810struct is_destructible<void>
2811    : public false_type {};
2812
2813#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2814template <class _Tp>
2815_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v
2816    = is_destructible<_Tp>::value;
2817#endif
2818
2819#endif // __has_keyword(__is_destructible)
2820
2821template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2822struct __member_pointer_traits_imp
2823{
2824};
2825
2826template <class _Rp, class _Class, class ..._Param>
2827struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2828{
2829    typedef _Class _ClassType;
2830    typedef _Rp _ReturnType;
2831    typedef _Rp (_FnType) (_Param...);
2832};
2833
2834template <class _Rp, class _Class, class ..._Param>
2835struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2836{
2837    typedef _Class _ClassType;
2838    typedef _Rp _ReturnType;
2839    typedef _Rp (_FnType) (_Param..., ...);
2840};
2841
2842template <class _Rp, class _Class, class ..._Param>
2843struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2844{
2845    typedef _Class const _ClassType;
2846    typedef _Rp _ReturnType;
2847    typedef _Rp (_FnType) (_Param...);
2848};
2849
2850template <class _Rp, class _Class, class ..._Param>
2851struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2852{
2853    typedef _Class const _ClassType;
2854    typedef _Rp _ReturnType;
2855    typedef _Rp (_FnType) (_Param..., ...);
2856};
2857
2858template <class _Rp, class _Class, class ..._Param>
2859struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2860{
2861    typedef _Class volatile _ClassType;
2862    typedef _Rp _ReturnType;
2863    typedef _Rp (_FnType) (_Param...);
2864};
2865
2866template <class _Rp, class _Class, class ..._Param>
2867struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2868{
2869    typedef _Class volatile _ClassType;
2870    typedef _Rp _ReturnType;
2871    typedef _Rp (_FnType) (_Param..., ...);
2872};
2873
2874template <class _Rp, class _Class, class ..._Param>
2875struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2876{
2877    typedef _Class const volatile _ClassType;
2878    typedef _Rp _ReturnType;
2879    typedef _Rp (_FnType) (_Param...);
2880};
2881
2882template <class _Rp, class _Class, class ..._Param>
2883struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2884{
2885    typedef _Class const volatile _ClassType;
2886    typedef _Rp _ReturnType;
2887    typedef _Rp (_FnType) (_Param..., ...);
2888};
2889
2890#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2891
2892template <class _Rp, class _Class, class ..._Param>
2893struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2894{
2895    typedef _Class& _ClassType;
2896    typedef _Rp _ReturnType;
2897    typedef _Rp (_FnType) (_Param...);
2898};
2899
2900template <class _Rp, class _Class, class ..._Param>
2901struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2902{
2903    typedef _Class& _ClassType;
2904    typedef _Rp _ReturnType;
2905    typedef _Rp (_FnType) (_Param..., ...);
2906};
2907
2908template <class _Rp, class _Class, class ..._Param>
2909struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2910{
2911    typedef _Class const& _ClassType;
2912    typedef _Rp _ReturnType;
2913    typedef _Rp (_FnType) (_Param...);
2914};
2915
2916template <class _Rp, class _Class, class ..._Param>
2917struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2918{
2919    typedef _Class const& _ClassType;
2920    typedef _Rp _ReturnType;
2921    typedef _Rp (_FnType) (_Param..., ...);
2922};
2923
2924template <class _Rp, class _Class, class ..._Param>
2925struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2926{
2927    typedef _Class volatile& _ClassType;
2928    typedef _Rp _ReturnType;
2929    typedef _Rp (_FnType) (_Param...);
2930};
2931
2932template <class _Rp, class _Class, class ..._Param>
2933struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2934{
2935    typedef _Class volatile& _ClassType;
2936    typedef _Rp _ReturnType;
2937    typedef _Rp (_FnType) (_Param..., ...);
2938};
2939
2940template <class _Rp, class _Class, class ..._Param>
2941struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2942{
2943    typedef _Class const volatile& _ClassType;
2944    typedef _Rp _ReturnType;
2945    typedef _Rp (_FnType) (_Param...);
2946};
2947
2948template <class _Rp, class _Class, class ..._Param>
2949struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2950{
2951    typedef _Class const volatile& _ClassType;
2952    typedef _Rp _ReturnType;
2953    typedef _Rp (_FnType) (_Param..., ...);
2954};
2955
2956template <class _Rp, class _Class, class ..._Param>
2957struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2958{
2959    typedef _Class&& _ClassType;
2960    typedef _Rp _ReturnType;
2961    typedef _Rp (_FnType) (_Param...);
2962};
2963
2964template <class _Rp, class _Class, class ..._Param>
2965struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2966{
2967    typedef _Class&& _ClassType;
2968    typedef _Rp _ReturnType;
2969    typedef _Rp (_FnType) (_Param..., ...);
2970};
2971
2972template <class _Rp, class _Class, class ..._Param>
2973struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2974{
2975    typedef _Class const&& _ClassType;
2976    typedef _Rp _ReturnType;
2977    typedef _Rp (_FnType) (_Param...);
2978};
2979
2980template <class _Rp, class _Class, class ..._Param>
2981struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2982{
2983    typedef _Class const&& _ClassType;
2984    typedef _Rp _ReturnType;
2985    typedef _Rp (_FnType) (_Param..., ...);
2986};
2987
2988template <class _Rp, class _Class, class ..._Param>
2989struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2990{
2991    typedef _Class volatile&& _ClassType;
2992    typedef _Rp _ReturnType;
2993    typedef _Rp (_FnType) (_Param...);
2994};
2995
2996template <class _Rp, class _Class, class ..._Param>
2997struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2998{
2999    typedef _Class volatile&& _ClassType;
3000    typedef _Rp _ReturnType;
3001    typedef _Rp (_FnType) (_Param..., ...);
3002};
3003
3004template <class _Rp, class _Class, class ..._Param>
3005struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
3006{
3007    typedef _Class const volatile&& _ClassType;
3008    typedef _Rp _ReturnType;
3009    typedef _Rp (_FnType) (_Param...);
3010};
3011
3012template <class _Rp, class _Class, class ..._Param>
3013struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
3014{
3015    typedef _Class const volatile&& _ClassType;
3016    typedef _Rp _ReturnType;
3017    typedef _Rp (_FnType) (_Param..., ...);
3018};
3019
3020#endif // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
3021
3022
3023template <class _Rp, class _Class>
3024struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
3025{
3026    typedef _Class _ClassType;
3027    typedef _Rp _ReturnType;
3028};
3029
3030template <class _MP>
3031struct __member_pointer_traits
3032    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
3033                    is_member_function_pointer<_MP>::value,
3034                    is_member_object_pointer<_MP>::value>
3035{
3036//     typedef ... _ClassType;
3037//     typedef ... _ReturnType;
3038//     typedef ... _FnType;
3039};
3040
3041
3042template <class _DecayedFp>
3043struct __member_pointer_class_type {};
3044
3045template <class _Ret, class _ClassType>
3046struct __member_pointer_class_type<_Ret _ClassType::*> {
3047  typedef _ClassType type;
3048};
3049
3050// template <class T, class... Args> struct is_constructible;
3051
3052#if defined(_LIBCPP_COMPILER_GCC) && _GNUC_VER_NEW >= 10000
3053# define _LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE
3054#endif
3055
3056#if !defined(_LIBCPP_CXX03_LANG) && !__has_feature(is_constructible) && !defined(_LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE)
3057
3058template <class _Tp, class... _Args>
3059struct __libcpp_is_constructible;
3060
3061template <class _To, class _From>
3062struct __is_invalid_base_to_derived_cast {
3063  static_assert(is_reference<_To>::value, "Wrong specialization");
3064  using _RawFrom = __uncvref_t<_From>;
3065  using _RawTo = __uncvref_t<_To>;
3066  static const bool value = _And<
3067        _IsNotSame<_RawFrom, _RawTo>,
3068        is_base_of<_RawFrom, _RawTo>,
3069        _Not<__libcpp_is_constructible<_RawTo, _From>>
3070  >::value;
3071};
3072
3073template <class _To, class _From>
3074struct __is_invalid_lvalue_to_rvalue_cast : false_type {
3075  static_assert(is_reference<_To>::value, "Wrong specialization");
3076};
3077
3078template <class _ToRef, class _FromRef>
3079struct __is_invalid_lvalue_to_rvalue_cast<_ToRef&&, _FromRef&> {
3080  using _RawFrom = __uncvref_t<_FromRef>;
3081  using _RawTo = __uncvref_t<_ToRef>;
3082  static const bool value = _And<
3083      _Not<is_function<_RawTo>>,
3084      _Or<
3085        _IsSame<_RawFrom, _RawTo>,
3086        is_base_of<_RawTo, _RawFrom>>
3087    >::value;
3088};
3089
3090struct __is_constructible_helper
3091{
3092    template <class _To>
3093    static void __eat(_To);
3094
3095    // This overload is needed to work around a Clang bug that disallows
3096    // static_cast<T&&>(e) for non-reference-compatible types.
3097    // Example: static_cast<int&&>(declval<double>());
3098    // NOTE: The static_cast implementation below is required to support
3099    //  classes with explicit conversion operators.
3100    template <class _To, class _From,
3101              class = decltype(__eat<_To>(declval<_From>()))>
3102    static true_type __test_cast(int);
3103
3104    template <class _To, class _From,
3105              class = decltype(static_cast<_To>(declval<_From>()))>
3106    static integral_constant<bool,
3107        !__is_invalid_base_to_derived_cast<_To, _From>::value &&
3108        !__is_invalid_lvalue_to_rvalue_cast<_To, _From>::value
3109    > __test_cast(long);
3110
3111    template <class, class>
3112    static false_type __test_cast(...);
3113
3114    template <class _Tp, class ..._Args,
3115        class = decltype(_Tp(declval<_Args>()...))>
3116    static true_type __test_nary(int);
3117    template <class _Tp, class...>
3118    static false_type __test_nary(...);
3119
3120    template <class _Tp, class _A0, class = decltype(::new _Tp(declval<_A0>()))>
3121    static is_destructible<_Tp> __test_unary(int);
3122    template <class, class>
3123    static false_type __test_unary(...);
3124};
3125
3126template <class _Tp, bool = is_void<_Tp>::value>
3127struct __is_default_constructible
3128    : decltype(__is_constructible_helper::__test_nary<_Tp>(0))
3129{};
3130
3131template <class _Tp>
3132struct __is_default_constructible<_Tp, true> : false_type {};
3133
3134template <class _Tp>
3135struct __is_default_constructible<_Tp[], false> : false_type {};
3136
3137template <class _Tp, size_t _Nx>
3138struct __is_default_constructible<_Tp[_Nx], false>
3139    : __is_default_constructible<typename remove_all_extents<_Tp>::type>  {};
3140
3141template <class _Tp, class... _Args>
3142struct __libcpp_is_constructible
3143{
3144  static_assert(sizeof...(_Args) > 1, "Wrong specialization");
3145  typedef decltype(__is_constructible_helper::__test_nary<_Tp, _Args...>(0))
3146      type;
3147};
3148
3149template <class _Tp>
3150struct __libcpp_is_constructible<_Tp> : __is_default_constructible<_Tp> {};
3151
3152template <class _Tp, class _A0>
3153struct __libcpp_is_constructible<_Tp, _A0>
3154    : public decltype(__is_constructible_helper::__test_unary<_Tp, _A0>(0))
3155{};
3156
3157template <class _Tp, class _A0>
3158struct __libcpp_is_constructible<_Tp&, _A0>
3159    : public decltype(__is_constructible_helper::
3160    __test_cast<_Tp&, _A0>(0))
3161{};
3162
3163template <class _Tp, class _A0>
3164struct __libcpp_is_constructible<_Tp&&, _A0>
3165    : public decltype(__is_constructible_helper::
3166    __test_cast<_Tp&&, _A0>(0))
3167{};
3168
3169#endif
3170
3171#if __has_feature(is_constructible) || defined(_LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE)
3172template <class _Tp, class ..._Args>
3173struct _LIBCPP_TEMPLATE_VIS is_constructible
3174    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
3175    {};
3176#else
3177template <class _Tp, class... _Args>
3178struct _LIBCPP_TEMPLATE_VIS is_constructible
3179    : public __libcpp_is_constructible<_Tp, _Args...>::type {};
3180#endif
3181
3182#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3183template <class _Tp, class ..._Args>
3184_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_constructible_v
3185    = is_constructible<_Tp, _Args...>::value;
3186#endif
3187
3188// is_default_constructible
3189
3190template <class _Tp>
3191struct _LIBCPP_TEMPLATE_VIS is_default_constructible
3192    : public is_constructible<_Tp>
3193    {};
3194
3195#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3196template <class _Tp>
3197_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_default_constructible_v
3198    = is_default_constructible<_Tp>::value;
3199#endif
3200
3201#ifndef _LIBCPP_CXX03_LANG
3202// First of all, we can't implement this check in C++03 mode because the {}
3203// default initialization syntax isn't valid.
3204// Second, we implement the trait in a funny manner with two defaulted template
3205// arguments to workaround Clang's PR43454.
3206template <class _Tp>
3207void __test_implicit_default_constructible(_Tp);
3208
3209template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
3210struct __is_implicitly_default_constructible
3211    : false_type
3212{ };
3213
3214template <class _Tp>
3215struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
3216    : true_type
3217{ };
3218
3219template <class _Tp>
3220struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
3221    : false_type
3222{ };
3223#endif // !C++03
3224
3225// is_copy_constructible
3226
3227template <class _Tp>
3228struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
3229    : public is_constructible<_Tp,
3230                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3231
3232#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3233template <class _Tp>
3234_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_constructible_v
3235    = is_copy_constructible<_Tp>::value;
3236#endif
3237
3238// is_move_constructible
3239
3240template <class _Tp>
3241struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3242    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3243    {};
3244
3245#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3246template <class _Tp>
3247_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_constructible_v
3248    = is_move_constructible<_Tp>::value;
3249#endif
3250
3251// is_trivially_constructible
3252
3253#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3254
3255template <class _Tp, class... _Args>
3256struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3257    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3258{
3259};
3260
3261#else  // !__has_feature(is_trivially_constructible)
3262
3263template <class _Tp, class... _Args>
3264struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3265    : false_type
3266{
3267};
3268
3269template <class _Tp>
3270struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp>
3271#if __has_feature(has_trivial_constructor) || defined(_LIBCPP_COMPILER_GCC)
3272    : integral_constant<bool, __has_trivial_constructor(_Tp)>
3273#else
3274    : integral_constant<bool, is_scalar<_Tp>::value>
3275#endif
3276{
3277};
3278
3279template <class _Tp>
3280struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&&>
3281    : integral_constant<bool, is_scalar<_Tp>::value>
3282{
3283};
3284
3285template <class _Tp>
3286struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, const _Tp&>
3287    : integral_constant<bool, is_scalar<_Tp>::value>
3288{
3289};
3290
3291template <class _Tp>
3292struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&>
3293    : integral_constant<bool, is_scalar<_Tp>::value>
3294{
3295};
3296
3297#endif // !__has_feature(is_trivially_constructible)
3298
3299
3300#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3301template <class _Tp, class... _Args>
3302_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_constructible_v
3303    = is_trivially_constructible<_Tp, _Args...>::value;
3304#endif
3305
3306// is_trivially_default_constructible
3307
3308template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3309    : public is_trivially_constructible<_Tp>
3310    {};
3311
3312#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3313template <class _Tp>
3314_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_default_constructible_v
3315    = is_trivially_default_constructible<_Tp>::value;
3316#endif
3317
3318// is_trivially_copy_constructible
3319
3320template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3321    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3322    {};
3323
3324#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3325template <class _Tp>
3326_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_constructible_v
3327    = is_trivially_copy_constructible<_Tp>::value;
3328#endif
3329
3330// is_trivially_move_constructible
3331
3332template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3333    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3334    {};
3335
3336#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3337template <class _Tp>
3338_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_constructible_v
3339    = is_trivially_move_constructible<_Tp>::value;
3340#endif
3341
3342// is_trivially_assignable
3343
3344#if __has_feature(is_trivially_assignable) || _GNUC_VER >= 501
3345
3346template <class _Tp, class _Arg>
3347struct is_trivially_assignable
3348    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3349{
3350};
3351
3352#else  // !__has_feature(is_trivially_assignable)
3353
3354template <class _Tp, class _Arg>
3355struct is_trivially_assignable
3356    : public false_type {};
3357
3358template <class _Tp>
3359struct is_trivially_assignable<_Tp&, _Tp>
3360    : integral_constant<bool, is_scalar<_Tp>::value> {};
3361
3362template <class _Tp>
3363struct is_trivially_assignable<_Tp&, _Tp&>
3364    : integral_constant<bool, is_scalar<_Tp>::value> {};
3365
3366template <class _Tp>
3367struct is_trivially_assignable<_Tp&, const _Tp&>
3368    : integral_constant<bool, is_scalar<_Tp>::value> {};
3369
3370template <class _Tp>
3371struct is_trivially_assignable<_Tp&, _Tp&&>
3372    : integral_constant<bool, is_scalar<_Tp>::value> {};
3373
3374#endif // !__has_feature(is_trivially_assignable)
3375
3376#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3377template <class _Tp, class _Arg>
3378_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_assignable_v
3379    = is_trivially_assignable<_Tp, _Arg>::value;
3380#endif
3381
3382// is_trivially_copy_assignable
3383
3384template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3385    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3386                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3387
3388#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3389template <class _Tp>
3390_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_assignable_v
3391    = is_trivially_copy_assignable<_Tp>::value;
3392#endif
3393
3394// is_trivially_move_assignable
3395
3396template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3397    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3398                                     typename add_rvalue_reference<_Tp>::type>
3399    {};
3400
3401#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3402template <class _Tp>
3403_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_assignable_v
3404    = is_trivially_move_assignable<_Tp>::value;
3405#endif
3406
3407// is_trivially_destructible
3408
3409#if __has_keyword(__is_trivially_destructible)
3410
3411template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3412    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3413
3414#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3415
3416template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3417    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3418
3419#else
3420
3421template <class _Tp> struct __libcpp_trivial_destructor
3422    : public integral_constant<bool, is_scalar<_Tp>::value ||
3423                                     is_reference<_Tp>::value> {};
3424
3425template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3426    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3427
3428template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3429    : public false_type {};
3430
3431#endif
3432
3433#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3434template <class _Tp>
3435_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_destructible_v
3436    = is_trivially_destructible<_Tp>::value;
3437#endif
3438
3439// is_nothrow_constructible
3440
3441#if __has_keyword(__is_nothrow_constructible)
3442
3443template <class _Tp, class... _Args>
3444struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3445    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3446
3447#else
3448
3449template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3450
3451template <class _Tp, class... _Args>
3452struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3453    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3454{
3455};
3456
3457template <class _Tp>
3458void __implicit_conversion_to(_Tp) noexcept { }
3459
3460template <class _Tp, class _Arg>
3461struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3462    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3463{
3464};
3465
3466template <class _Tp, bool _IsReference, class... _Args>
3467struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3468    : public false_type
3469{
3470};
3471
3472template <class _Tp, class... _Args>
3473struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3474    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3475{
3476};
3477
3478template <class _Tp, size_t _Ns>
3479struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3480    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3481{
3482};
3483
3484#endif // _LIBCPP_HAS_NO_NOEXCEPT
3485
3486
3487#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3488template <class _Tp, class ..._Args>
3489_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_constructible_v
3490    = is_nothrow_constructible<_Tp, _Args...>::value;
3491#endif
3492
3493// is_nothrow_default_constructible
3494
3495template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3496    : public is_nothrow_constructible<_Tp>
3497    {};
3498
3499#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3500template <class _Tp>
3501_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_default_constructible_v
3502    = is_nothrow_default_constructible<_Tp>::value;
3503#endif
3504
3505// is_nothrow_copy_constructible
3506
3507template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3508    : public is_nothrow_constructible<_Tp,
3509                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3510
3511#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3512template <class _Tp>
3513_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_constructible_v
3514    = is_nothrow_copy_constructible<_Tp>::value;
3515#endif
3516
3517// is_nothrow_move_constructible
3518
3519template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3520    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3521    {};
3522
3523#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3524template <class _Tp>
3525_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_constructible_v
3526    = is_nothrow_move_constructible<_Tp>::value;
3527#endif
3528
3529// is_nothrow_assignable
3530
3531#if __has_keyword(__is_nothrow_assignable)
3532
3533template <class _Tp, class _Arg>
3534struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3535    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3536
3537#else
3538
3539template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3540
3541template <class _Tp, class _Arg>
3542struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3543    : public false_type
3544{
3545};
3546
3547template <class _Tp, class _Arg>
3548struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3549    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
3550{
3551};
3552
3553template <class _Tp, class _Arg>
3554struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3555    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3556{
3557};
3558
3559#endif // _LIBCPP_HAS_NO_NOEXCEPT
3560
3561#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3562template <class _Tp, class _Arg>
3563_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_assignable_v
3564    = is_nothrow_assignable<_Tp, _Arg>::value;
3565#endif
3566
3567// is_nothrow_copy_assignable
3568
3569template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3570    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3571                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3572
3573#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3574template <class _Tp>
3575_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_assignable_v
3576    = is_nothrow_copy_assignable<_Tp>::value;
3577#endif
3578
3579// is_nothrow_move_assignable
3580
3581template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3582    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3583                                     typename add_rvalue_reference<_Tp>::type>
3584    {};
3585
3586#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3587template <class _Tp>
3588_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_assignable_v
3589    = is_nothrow_move_assignable<_Tp>::value;
3590#endif
3591
3592// is_nothrow_destructible
3593
3594#if !defined(_LIBCPP_CXX03_LANG)
3595
3596template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3597
3598template <class _Tp>
3599struct __libcpp_is_nothrow_destructible<false, _Tp>
3600    : public false_type
3601{
3602};
3603
3604template <class _Tp>
3605struct __libcpp_is_nothrow_destructible<true, _Tp>
3606    : public integral_constant<bool, noexcept(declval<_Tp>().~_Tp()) >
3607{
3608};
3609
3610template <class _Tp>
3611struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3612    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3613{
3614};
3615
3616template <class _Tp, size_t _Ns>
3617struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3618    : public is_nothrow_destructible<_Tp>
3619{
3620};
3621
3622template <class _Tp>
3623struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3624    : public true_type
3625{
3626};
3627
3628template <class _Tp>
3629struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3630    : public true_type
3631{
3632};
3633
3634#else
3635
3636template <class _Tp> struct __libcpp_nothrow_destructor
3637    : public integral_constant<bool, is_scalar<_Tp>::value ||
3638                                     is_reference<_Tp>::value> {};
3639
3640template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3641    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3642
3643template <class _Tp>
3644struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3645    : public false_type {};
3646
3647#endif
3648
3649#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3650template <class _Tp>
3651_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_destructible_v
3652    = is_nothrow_destructible<_Tp>::value;
3653#endif
3654
3655// is_pod
3656
3657#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3658
3659template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3660    : public integral_constant<bool, __is_pod(_Tp)> {};
3661
3662#else
3663
3664template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3665    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3666                                     is_trivially_copy_constructible<_Tp>::value      &&
3667                                     is_trivially_copy_assignable<_Tp>::value    &&
3668                                     is_trivially_destructible<_Tp>::value> {};
3669
3670#endif
3671
3672#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3673template <class _Tp>
3674_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pod_v
3675    = is_pod<_Tp>::value;
3676#endif
3677
3678// is_literal_type;
3679
3680#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3681template <class _Tp> struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 is_literal_type
3682    : public integral_constant<bool, __is_literal_type(_Tp)>
3683    {};
3684
3685#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3686template <class _Tp>
3687_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_literal_type_v
3688    = is_literal_type<_Tp>::value;
3689#endif // _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3690#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3691
3692// is_standard_layout;
3693
3694template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3695#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3696    : public integral_constant<bool, __is_standard_layout(_Tp)>
3697#else
3698    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3699#endif
3700    {};
3701
3702#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3703template <class _Tp>
3704_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_standard_layout_v
3705    = is_standard_layout<_Tp>::value;
3706#endif
3707
3708// is_trivially_copyable;
3709
3710template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3711#if __has_feature(is_trivially_copyable)
3712    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3713#elif _GNUC_VER >= 501
3714    : public integral_constant<bool, !is_volatile<_Tp>::value && __is_trivially_copyable(_Tp)>
3715#else
3716    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3717#endif
3718    {};
3719
3720#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3721template <class _Tp>
3722_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copyable_v
3723    = is_trivially_copyable<_Tp>::value;
3724#endif
3725
3726// is_trivial;
3727
3728template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3729#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3730    : public integral_constant<bool, __is_trivial(_Tp)>
3731#else
3732    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3733                                 is_trivially_default_constructible<_Tp>::value>
3734#endif
3735    {};
3736
3737#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3738template <class _Tp>
3739_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivial_v
3740    = is_trivial<_Tp>::value;
3741#endif
3742
3743template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3744template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3745template <class _Tp> struct __is_reference_wrapper
3746    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3747
3748#ifndef _LIBCPP_CXX03_LANG
3749
3750template <class _Fp, class _A0,
3751         class _DecayFp = typename decay<_Fp>::type,
3752         class _DecayA0 = typename decay<_A0>::type,
3753         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3754using __enable_if_bullet1 = typename enable_if
3755    <
3756        is_member_function_pointer<_DecayFp>::value
3757        && is_base_of<_ClassT, _DecayA0>::value
3758    >::type;
3759
3760template <class _Fp, class _A0,
3761         class _DecayFp = typename decay<_Fp>::type,
3762         class _DecayA0 = typename decay<_A0>::type>
3763using __enable_if_bullet2 = typename enable_if
3764    <
3765        is_member_function_pointer<_DecayFp>::value
3766        && __is_reference_wrapper<_DecayA0>::value
3767    >::type;
3768
3769template <class _Fp, class _A0,
3770         class _DecayFp = typename decay<_Fp>::type,
3771         class _DecayA0 = typename decay<_A0>::type,
3772         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3773using __enable_if_bullet3 = typename enable_if
3774    <
3775        is_member_function_pointer<_DecayFp>::value
3776        && !is_base_of<_ClassT, _DecayA0>::value
3777        && !__is_reference_wrapper<_DecayA0>::value
3778    >::type;
3779
3780template <class _Fp, class _A0,
3781         class _DecayFp = typename decay<_Fp>::type,
3782         class _DecayA0 = typename decay<_A0>::type,
3783         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3784using __enable_if_bullet4 = typename enable_if
3785    <
3786        is_member_object_pointer<_DecayFp>::value
3787        && is_base_of<_ClassT, _DecayA0>::value
3788    >::type;
3789
3790template <class _Fp, class _A0,
3791         class _DecayFp = typename decay<_Fp>::type,
3792         class _DecayA0 = typename decay<_A0>::type>
3793using __enable_if_bullet5 = typename enable_if
3794    <
3795        is_member_object_pointer<_DecayFp>::value
3796        && __is_reference_wrapper<_DecayA0>::value
3797    >::type;
3798
3799template <class _Fp, class _A0,
3800         class _DecayFp = typename decay<_Fp>::type,
3801         class _DecayA0 = typename decay<_A0>::type,
3802         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3803using __enable_if_bullet6 = typename enable_if
3804    <
3805        is_member_object_pointer<_DecayFp>::value
3806        && !is_base_of<_ClassT, _DecayA0>::value
3807        && !__is_reference_wrapper<_DecayA0>::value
3808    >::type;
3809
3810// __invoke forward declarations
3811
3812// fall back - none of the bullets
3813
3814#define _LIBCPP_INVOKE_RETURN(...) \
3815    noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) \
3816    { return __VA_ARGS__; }
3817
3818template <class ..._Args>
3819auto __invoke(__any, _Args&& ...__args) -> __nat;
3820
3821template <class ..._Args>
3822auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3823
3824// bullets 1, 2 and 3
3825
3826template <class _Fp, class _A0, class ..._Args,
3827          class = __enable_if_bullet1<_Fp, _A0>>
3828inline _LIBCPP_INLINE_VISIBILITY
3829_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3830__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3831_LIBCPP_INVOKE_RETURN((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3832
3833template <class _Fp, class _A0, class ..._Args,
3834          class = __enable_if_bullet1<_Fp, _A0>>
3835inline _LIBCPP_INLINE_VISIBILITY
3836_LIBCPP_CONSTEXPR auto
3837__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3838_LIBCPP_INVOKE_RETURN((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3839
3840template <class _Fp, class _A0, class ..._Args,
3841          class = __enable_if_bullet2<_Fp, _A0>>
3842inline _LIBCPP_INLINE_VISIBILITY
3843_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3844__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3845_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3846
3847template <class _Fp, class _A0, class ..._Args,
3848          class = __enable_if_bullet2<_Fp, _A0>>
3849inline _LIBCPP_INLINE_VISIBILITY
3850_LIBCPP_CONSTEXPR auto
3851__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3852_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3853
3854template <class _Fp, class _A0, class ..._Args,
3855          class = __enable_if_bullet3<_Fp, _A0>>
3856inline _LIBCPP_INLINE_VISIBILITY
3857_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3858__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3859_LIBCPP_INVOKE_RETURN(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3860
3861template <class _Fp, class _A0, class ..._Args,
3862          class = __enable_if_bullet3<_Fp, _A0>>
3863inline _LIBCPP_INLINE_VISIBILITY
3864_LIBCPP_CONSTEXPR auto
3865__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3866_LIBCPP_INVOKE_RETURN(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3867
3868// bullets 4, 5 and 6
3869
3870template <class _Fp, class _A0,
3871          class = __enable_if_bullet4<_Fp, _A0>>
3872inline _LIBCPP_INLINE_VISIBILITY
3873_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3874__invoke(_Fp&& __f, _A0&& __a0)
3875_LIBCPP_INVOKE_RETURN(static_cast<_A0&&>(__a0).*__f)
3876
3877template <class _Fp, class _A0,
3878          class = __enable_if_bullet4<_Fp, _A0>>
3879inline _LIBCPP_INLINE_VISIBILITY
3880_LIBCPP_CONSTEXPR auto
3881__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3882_LIBCPP_INVOKE_RETURN(static_cast<_A0&&>(__a0).*__f)
3883
3884template <class _Fp, class _A0,
3885          class = __enable_if_bullet5<_Fp, _A0>>
3886inline _LIBCPP_INLINE_VISIBILITY
3887_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3888__invoke(_Fp&& __f, _A0&& __a0)
3889_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3890
3891template <class _Fp, class _A0,
3892          class = __enable_if_bullet5<_Fp, _A0>>
3893inline _LIBCPP_INLINE_VISIBILITY
3894_LIBCPP_CONSTEXPR auto
3895__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3896_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3897
3898template <class _Fp, class _A0,
3899          class = __enable_if_bullet6<_Fp, _A0>>
3900inline _LIBCPP_INLINE_VISIBILITY
3901_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3902__invoke(_Fp&& __f, _A0&& __a0)
3903_LIBCPP_INVOKE_RETURN((*static_cast<_A0&&>(__a0)).*__f)
3904
3905template <class _Fp, class _A0,
3906          class = __enable_if_bullet6<_Fp, _A0>>
3907inline _LIBCPP_INLINE_VISIBILITY
3908_LIBCPP_CONSTEXPR auto
3909__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3910_LIBCPP_INVOKE_RETURN((*static_cast<_A0&&>(__a0)).*__f)
3911
3912// bullet 7
3913
3914template <class _Fp, class ..._Args>
3915inline _LIBCPP_INLINE_VISIBILITY
3916_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3917__invoke(_Fp&& __f, _Args&& ...__args)
3918_LIBCPP_INVOKE_RETURN(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3919
3920template <class _Fp, class ..._Args>
3921inline _LIBCPP_INLINE_VISIBILITY
3922_LIBCPP_CONSTEXPR auto
3923__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3924_LIBCPP_INVOKE_RETURN(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3925
3926#undef _LIBCPP_INVOKE_RETURN
3927
3928// __invokable
3929template <class _Ret, class _Fp, class ..._Args>
3930struct __invokable_r
3931{
3932  template <class _XFp, class ..._XArgs>
3933  static auto __try_call(int) -> decltype(
3934    _VSTD::__invoke(declval<_XFp>(), declval<_XArgs>()...));
3935  template <class _XFp, class ..._XArgs>
3936  static __nat __try_call(...);
3937
3938  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3939  // or incomplete array types as required by the standard.
3940  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3941
3942  using type =
3943  typename conditional<
3944      _IsNotSame<_Result, __nat>::value,
3945      typename conditional<
3946          is_void<_Ret>::value,
3947          true_type,
3948          is_convertible<_Result, _Ret>
3949      >::type,
3950      false_type
3951  >::type;
3952  static const bool value = type::value;
3953};
3954template <class _Fp, class ..._Args>
3955using __invokable = __invokable_r<void, _Fp, _Args...>;
3956
3957template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3958struct __nothrow_invokable_r_imp {
3959  static const bool value = false;
3960};
3961
3962template <class _Ret, class _Fp, class ..._Args>
3963struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3964{
3965    typedef __nothrow_invokable_r_imp _ThisT;
3966
3967    template <class _Tp>
3968    static void __test_noexcept(_Tp) noexcept;
3969
3970    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3971        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...)));
3972};
3973
3974template <class _Ret, class _Fp, class ..._Args>
3975struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3976{
3977    static const bool value = noexcept(
3978        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...));
3979};
3980
3981template <class _Ret, class _Fp, class ..._Args>
3982using __nothrow_invokable_r =
3983    __nothrow_invokable_r_imp<
3984            __invokable_r<_Ret, _Fp, _Args...>::value,
3985            is_void<_Ret>::value,
3986            _Ret, _Fp, _Args...
3987    >;
3988
3989template <class _Fp, class ..._Args>
3990using __nothrow_invokable =
3991    __nothrow_invokable_r_imp<
3992            __invokable<_Fp, _Args...>::value,
3993            true, void, _Fp, _Args...
3994    >;
3995
3996template <class _Fp, class ..._Args>
3997struct __invoke_of
3998    : public enable_if<
3999        __invokable<_Fp, _Args...>::value,
4000        typename __invokable_r<void, _Fp, _Args...>::_Result>
4001{
4002};
4003
4004#endif // _LIBCPP_CXX03_LANG
4005
4006// result_of
4007
4008#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
4009template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
4010
4011#ifndef _LIBCPP_CXX03_LANG
4012
4013template <class _Fp, class ..._Args>
4014class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
4015    : public __invoke_of<_Fp, _Args...>
4016{
4017};
4018
4019#else // C++03
4020
4021template <class _Fn, bool, bool>
4022class __result_of
4023{
4024};
4025
4026template <class _Fn, class ..._Args>
4027class __result_of<_Fn(_Args...), true, false>
4028{
4029public:
4030    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
4031};
4032
4033template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
4034struct __result_of_mp;
4035
4036// member function pointer
4037
4038template <class _MP, class _Tp>
4039struct __result_of_mp<_MP, _Tp, true>
4040{
4041    using type = typename __member_pointer_traits<_MP>::_ReturnType;
4042};
4043
4044// member data pointer
4045
4046template <class _MP, class _Tp, bool>
4047struct __result_of_mdp;
4048
4049template <class _Rp, class _Class, class _Tp>
4050struct __result_of_mdp<_Rp _Class::*, _Tp, false>
4051{
4052    using type = typename __apply_cv<decltype(*declval<_Tp>()), _Rp>::type&;
4053};
4054
4055template <class _Rp, class _Class, class _Tp>
4056struct __result_of_mdp<_Rp _Class::*, _Tp, true>
4057{
4058    using type = typename __apply_cv<_Tp, _Rp>::type&;
4059};
4060
4061template <class _Rp, class _Class, class _Tp>
4062struct __result_of_mp<_Rp _Class::*, _Tp, false>
4063    : public __result_of_mdp<_Rp _Class::*, _Tp,
4064            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
4065{
4066};
4067
4068template <class _Fn, class _Tp>
4069class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
4070    : public __result_of_mp<typename remove_reference<_Fn>::type,
4071                            _Tp,
4072                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
4073{
4074};
4075
4076template <class _Fn, class _Tp, class ..._Args>
4077class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
4078    : public __result_of_mp<typename remove_reference<_Fn>::type,
4079                            _Tp,
4080                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
4081{
4082};
4083
4084template <class _Fn, class ..._Args>
4085class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
4086    : public __result_of<_Fn(_Args...),
4087                         is_class<typename remove_reference<_Fn>::type>::value ||
4088                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
4089                         is_member_pointer<typename remove_reference<_Fn>::type>::value
4090                        >
4091{
4092};
4093
4094#endif // C++03
4095
4096#if _LIBCPP_STD_VER > 11
4097template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
4098#endif // _LIBCPP_STD_VER > 11
4099#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
4100
4101#if _LIBCPP_STD_VER > 14
4102
4103// invoke_result
4104
4105template <class _Fn, class... _Args>
4106struct _LIBCPP_TEMPLATE_VIS invoke_result
4107    : __invoke_of<_Fn, _Args...>
4108{
4109};
4110
4111template <class _Fn, class... _Args>
4112using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
4113
4114// is_invocable
4115
4116template <class _Fn, class ..._Args>
4117struct _LIBCPP_TEMPLATE_VIS is_invocable
4118    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
4119
4120template <class _Ret, class _Fn, class ..._Args>
4121struct _LIBCPP_TEMPLATE_VIS is_invocable_r
4122    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
4123
4124template <class _Fn, class ..._Args>
4125_LIBCPP_INLINE_VAR constexpr bool is_invocable_v
4126    = is_invocable<_Fn, _Args...>::value;
4127
4128template <class _Ret, class _Fn, class ..._Args>
4129_LIBCPP_INLINE_VAR constexpr bool is_invocable_r_v
4130    = is_invocable_r<_Ret, _Fn, _Args...>::value;
4131
4132// is_nothrow_invocable
4133
4134template <class _Fn, class ..._Args>
4135struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
4136    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
4137
4138template <class _Ret, class _Fn, class ..._Args>
4139struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
4140    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
4141
4142template <class _Fn, class ..._Args>
4143_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_v
4144    = is_nothrow_invocable<_Fn, _Args...>::value;
4145
4146template <class _Ret, class _Fn, class ..._Args>
4147_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_r_v
4148    = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
4149
4150#endif // _LIBCPP_STD_VER > 14
4151
4152// __swappable
4153
4154template <class _Tp> struct __is_swappable;
4155template <class _Tp> struct __is_nothrow_swappable;
4156
4157
4158#ifndef _LIBCPP_CXX03_LANG
4159template <class _Tp>
4160using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
4161#else
4162template <class>
4163using __swap_result_t = void;
4164#endif
4165
4166template <class _Tp>
4167inline _LIBCPP_INLINE_VISIBILITY
4168_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
4169swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
4170                                    is_nothrow_move_assignable<_Tp>::value);
4171
4172template<class _Tp, size_t _Np>
4173inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4174typename enable_if<
4175    __is_swappable<_Tp>::value
4176>::type
4177swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
4178
4179namespace __detail
4180{
4181// ALL generic swap overloads MUST already have a declaration available at this point.
4182
4183template <class _Tp, class _Up = _Tp,
4184          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
4185struct __swappable_with
4186{
4187    template <class _LHS, class _RHS>
4188    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
4189    __test_swap(int);
4190    template <class, class>
4191    static __nat __test_swap(long);
4192
4193    // Extra parens are needed for the C++03 definition of decltype.
4194    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
4195    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
4196
4197    static const bool value = _IsNotSame<__swap1, __nat>::value
4198                           && _IsNotSame<__swap2, __nat>::value;
4199};
4200
4201template <class _Tp, class _Up>
4202struct __swappable_with<_Tp, _Up,  false> : false_type {};
4203
4204template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
4205struct __nothrow_swappable_with {
4206  static const bool value =
4207#ifndef _LIBCPP_HAS_NO_NOEXCEPT
4208      noexcept(swap(declval<_Tp>(), declval<_Up>()))
4209  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
4210#else
4211      false;
4212#endif
4213};
4214
4215template <class _Tp, class _Up>
4216struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
4217
4218}  // __detail
4219
4220template <class _Tp>
4221struct __is_swappable
4222    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
4223{
4224};
4225
4226template <class _Tp>
4227struct __is_nothrow_swappable
4228    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
4229{
4230};
4231
4232#if _LIBCPP_STD_VER > 14
4233
4234template <class _Tp, class _Up>
4235struct _LIBCPP_TEMPLATE_VIS is_swappable_with
4236    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
4237{
4238};
4239
4240template <class _Tp>
4241struct _LIBCPP_TEMPLATE_VIS is_swappable
4242    : public conditional<
4243        __is_referenceable<_Tp>::value,
4244        is_swappable_with<
4245            typename add_lvalue_reference<_Tp>::type,
4246            typename add_lvalue_reference<_Tp>::type>,
4247        false_type
4248    >::type
4249{
4250};
4251
4252template <class _Tp, class _Up>
4253struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
4254    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
4255{
4256};
4257
4258template <class _Tp>
4259struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
4260    : public conditional<
4261        __is_referenceable<_Tp>::value,
4262        is_nothrow_swappable_with<
4263            typename add_lvalue_reference<_Tp>::type,
4264            typename add_lvalue_reference<_Tp>::type>,
4265        false_type
4266    >::type
4267{
4268};
4269
4270template <class _Tp, class _Up>
4271_LIBCPP_INLINE_VAR constexpr bool is_swappable_with_v
4272    = is_swappable_with<_Tp, _Up>::value;
4273
4274template <class _Tp>
4275_LIBCPP_INLINE_VAR constexpr bool is_swappable_v
4276    = is_swappable<_Tp>::value;
4277
4278template <class _Tp, class _Up>
4279_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_with_v
4280    = is_nothrow_swappable_with<_Tp, _Up>::value;
4281
4282template <class _Tp>
4283_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_v
4284    = is_nothrow_swappable<_Tp>::value;
4285
4286#endif // _LIBCPP_STD_VER > 14
4287
4288template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4289
4290template <class _Tp>
4291struct __underlying_type_impl<_Tp, false> {};
4292
4293template <class _Tp>
4294struct __underlying_type_impl<_Tp, true>
4295{
4296    typedef __underlying_type(_Tp) type;
4297};
4298
4299template <class _Tp>
4300struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4301
4302#if _LIBCPP_STD_VER > 11
4303template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4304#endif
4305
4306template <class _Tp, bool = is_enum<_Tp>::value>
4307struct __sfinae_underlying_type
4308{
4309    typedef typename underlying_type<_Tp>::type type;
4310    typedef decltype(((type)1) + 0) __promoted_type;
4311};
4312
4313template <class _Tp>
4314struct __sfinae_underlying_type<_Tp, false> {};
4315
4316inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4317int __convert_to_integral(int __val) { return __val; }
4318
4319inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4320unsigned __convert_to_integral(unsigned __val) { return __val; }
4321
4322inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4323long __convert_to_integral(long __val) { return __val; }
4324
4325inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4326unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4327
4328inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4329long long __convert_to_integral(long long __val) { return __val; }
4330
4331inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4332unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4333
4334template<typename _Fp>
4335inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4336typename enable_if<is_floating_point<_Fp>::value, long long>::type
4337 __convert_to_integral(_Fp __val) { return __val; }
4338
4339#ifndef _LIBCPP_HAS_NO_INT128
4340inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4341__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4342
4343inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4344__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4345#endif
4346
4347template <class _Tp>
4348inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4349typename __sfinae_underlying_type<_Tp>::__promoted_type
4350__convert_to_integral(_Tp __val) { return __val; }
4351
4352#ifndef _LIBCPP_CXX03_LANG
4353
4354template <class _Tp>
4355struct __has_operator_addressof_member_imp
4356{
4357    template <class _Up>
4358        static auto __test(int)
4359            -> typename __select_2nd<decltype(declval<_Up>().operator&()), true_type>::type;
4360    template <class>
4361        static auto __test(long) -> false_type;
4362
4363    static const bool value = decltype(__test<_Tp>(0))::value;
4364};
4365
4366template <class _Tp>
4367struct __has_operator_addressof_free_imp
4368{
4369    template <class _Up>
4370        static auto __test(int)
4371            -> typename __select_2nd<decltype(operator&(declval<_Up>())), true_type>::type;
4372    template <class>
4373        static auto __test(long) -> false_type;
4374
4375    static const bool value = decltype(__test<_Tp>(0))::value;
4376};
4377
4378template <class _Tp>
4379struct __has_operator_addressof
4380    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
4381                                  || __has_operator_addressof_free_imp<_Tp>::value>
4382{};
4383
4384#endif // _LIBCPP_CXX03_LANG
4385
4386// is_scoped_enum [meta.unary.prop]
4387
4388#if _LIBCPP_STD_VER > 20
4389template <class _Tp, bool = is_enum_v<_Tp> >
4390struct __is_scoped_enum_helper : false_type {};
4391
4392template <class _Tp>
4393struct __is_scoped_enum_helper<_Tp, true>
4394    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
4395
4396template <class _Tp>
4397struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
4398    : public __is_scoped_enum_helper<_Tp> {};
4399
4400template <class _Tp>
4401_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scoped_enum_v =
4402    is_scoped_enum<_Tp>::value;
4403#endif
4404
4405#if _LIBCPP_STD_VER > 14
4406
4407template <class... _Args>
4408struct conjunction : _And<_Args...> {};
4409template<class... _Args>
4410_LIBCPP_INLINE_VAR constexpr bool conjunction_v
4411    = conjunction<_Args...>::value;
4412
4413template <class... _Args>
4414struct disjunction : _Or<_Args...> {};
4415template<class... _Args>
4416_LIBCPP_INLINE_VAR constexpr bool disjunction_v
4417    = disjunction<_Args...>::value;
4418
4419template <class _Tp>
4420struct negation : _Not<_Tp> {};
4421template<class _Tp>
4422_LIBCPP_INLINE_VAR constexpr bool negation_v
4423    = negation<_Tp>::value;
4424#endif // _LIBCPP_STD_VER > 14
4425
4426// These traits are used in __tree and __hash_table
4427struct __extract_key_fail_tag {};
4428struct __extract_key_self_tag {};
4429struct __extract_key_first_tag {};
4430
4431template <class _ValTy, class _Key,
4432          class _RawValTy = typename __unconstref<_ValTy>::type>
4433struct __can_extract_key
4434    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4435                  __extract_key_fail_tag>::type {};
4436
4437template <class _Pair, class _Key, class _First, class _Second>
4438struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
4439    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4440                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4441
4442// __can_extract_map_key uses true_type/false_type instead of the tags.
4443// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4444// and _ValTy == _Key.
4445template <class _ValTy, class _Key, class _ContainerValueTy,
4446          class _RawValTy = typename __unconstref<_ValTy>::type>
4447struct __can_extract_map_key
4448    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4449
4450// This specialization returns __extract_key_fail_tag for non-map containers
4451// because _Key == _ContainerValueTy
4452template <class _ValTy, class _Key, class _RawValTy>
4453struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4454    : false_type {};
4455
4456#ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
4457#if _LIBCPP_STD_VER > 17
4458_LIBCPP_INLINE_VISIBILITY
4459inline constexpr bool is_constant_evaluated() noexcept {
4460  return __builtin_is_constant_evaluated();
4461}
4462#endif
4463
4464inline _LIBCPP_CONSTEXPR
4465bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4466#else
4467inline _LIBCPP_CONSTEXPR
4468bool __libcpp_is_constant_evaluated() _NOEXCEPT { return false; }
4469#endif
4470
4471template <class _CharT>
4472using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4473
4474template<class _Tp>
4475using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
4476
4477#if _LIBCPP_STD_VER > 17
4478template<bool _Const, class _Tp>
4479using __maybe_const = conditional_t<_Const, const _Tp, _Tp>;
4480#endif // _LIBCPP_STD_VER > 17
4481
4482_LIBCPP_END_NAMESPACE_STD
4483
4484#if _LIBCPP_STD_VER > 14
4485// std::byte
4486namespace std  // purposefully not versioned
4487{
4488
4489
4490}
4491#endif
4492
4493#endif // _LIBCPP_TYPE_TRAITS
4494