1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_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 <__assert> // all public C++ headers provide the assertion handler
420#include <__config>
421#include <__type_traits/add_pointer.h>
422#include <__type_traits/conditional.h>
423#include <__type_traits/decay.h>
424#include <__type_traits/enable_if.h>
425#include <__type_traits/integral_constant.h>
426#include <__type_traits/is_array.h>
427#include <__type_traits/is_base_of.h>
428#include <__type_traits/is_callable.h>
429#include <__type_traits/is_const.h>
430#include <__type_traits/is_convertible.h>
431#include <__type_traits/is_floating_point.h>
432#include <__type_traits/is_function.h>
433#include <__type_traits/is_integral.h>
434#include <__type_traits/is_member_function_pointer.h>
435#include <__type_traits/is_member_object_pointer.h>
436#include <__type_traits/is_null_pointer.h>
437#include <__type_traits/is_reference.h>
438#include <__type_traits/is_reference_wrapper.h>
439#include <__type_traits/is_referenceable.h>
440#include <__type_traits/is_same.h>
441#include <__type_traits/is_void.h>
442#include <__type_traits/is_volatile.h>
443#include <__type_traits/remove_const.h>
444#include <__type_traits/remove_cv.h>
445#include <__type_traits/remove_extent.h>
446#include <__type_traits/remove_reference.h>
447#include <__type_traits/remove_volatile.h>
448#include <__utility/declval.h>
449#include <cstddef>
450#include <version>
451
452#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
453#  pragma GCC system_header
454#endif
455
456_LIBCPP_BEGIN_NAMESPACE_STD
457
458template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
459template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
460
461template <bool> struct _MetaBase;
462template <>
463struct _MetaBase<true> {
464  template <class _Tp, class _Up>
465  using _SelectImpl _LIBCPP_NODEBUG = _Tp;
466  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
467  using _SelectApplyImpl _LIBCPP_NODEBUG = _FirstFn<_Args...>;
468  template <class _First, class...>
469  using _FirstImpl _LIBCPP_NODEBUG = _First;
470  template <class, class _Second, class...>
471  using _SecondImpl _LIBCPP_NODEBUG = _Second;
472  template <class _Result, class _First, class ..._Rest>
473  using _OrImpl _LIBCPP_NODEBUG = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
474};
475
476template <>
477struct _MetaBase<false> {
478  template <class _Tp, class _Up>
479  using _SelectImpl _LIBCPP_NODEBUG = _Up;
480  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
481  using _SelectApplyImpl _LIBCPP_NODEBUG = _SecondFn<_Args...>;
482  template <class _Result, class ...>
483  using _OrImpl _LIBCPP_NODEBUG = _Result;
484};
485template <bool _Cond, class _IfRes, class _ElseRes>
486using _If _LIBCPP_NODEBUG = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
487template <class ..._Rest>
488using _Or _LIBCPP_NODEBUG = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
489template <class _Pred>
490struct _Not : _BoolConstant<!_Pred::value> {};
491template <class ..._Args>
492using _FirstType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
493template <class ..._Args>
494using _SecondType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
495
496template <class ...> using __expand_to_true = true_type;
497template <class ..._Pred>
498__expand_to_true<__enable_if_t<_Pred::value>...> __and_helper(int);
499template <class ...>
500false_type __and_helper(...);
501template <class ..._Pred>
502using _And _LIBCPP_NODEBUG = decltype(__and_helper<_Pred...>(0));
503
504template <template <class...> class _Func, class ..._Args>
505struct _Lazy : _Func<_Args...> {};
506
507// Member detector base
508
509template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
510true_type __sfinae_test_impl(int);
511template <template <class...> class, class ...>
512false_type __sfinae_test_impl(...);
513
514template <template <class ...> class _Templ, class ..._Args>
515using _IsValidExpansion _LIBCPP_NODEBUG = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
516
517template <class>
518struct __void_t { typedef void type; };
519
520template <class _Tp, bool>
521struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
522
523// is_same
524
525template <class _Tp>
526using __test_for_primary_template = __enable_if_t<
527    _IsSame<_Tp, typename _Tp::__primary_template>::value
528  >;
529template <class _Tp>
530using __is_primary_template = _IsValidExpansion<
531    __test_for_primary_template, _Tp
532  >;
533
534// is_integral
535
536// [basic.fundamental] defines five standard signed integer types;
537// __int128_t is an extended signed integer type.
538// The signed and unsigned integer types, plus bool and the
539// five types with "char" in their name, compose the "integral" types.
540
541template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
542template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
543template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
544template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
545template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
546template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
547#ifndef _LIBCPP_HAS_NO_INT128
548template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
549#endif
550
551template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
552template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
553template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
554template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
555template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
556template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
557#ifndef _LIBCPP_HAS_NO_INT128
558template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
559#endif
560
561// is_pointer
562
563// Before AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
564#if __has_keyword(__is_pointer) &&                                             \
565    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
566
567template<class _Tp>
568struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
569
570#if _LIBCPP_STD_VER > 14
571template <class _Tp>
572inline constexpr bool is_pointer_v = __is_pointer(_Tp);
573#endif
574
575#else // __has_keyword(__is_pointer)
576
577template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
578template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
579
580template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
581#if defined(_LIBCPP_HAS_OBJC_ARC)
582template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
583template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
584template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
585template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
586#endif
587
588template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
589    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
590
591#if _LIBCPP_STD_VER > 14
592template <class _Tp>
593inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
594#endif
595
596#endif // __has_keyword(__is_pointer)
597
598// is_union
599
600#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
601
602template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
603    : public integral_constant<bool, __is_union(_Tp)> {};
604
605#else
606
607template <class _Tp> struct __libcpp_union : public false_type {};
608template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
609    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
610
611#endif
612
613#if _LIBCPP_STD_VER > 14
614template <class _Tp>
615inline constexpr bool is_union_v = is_union<_Tp>::value;
616#endif
617
618// is_class
619
620#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
621
622template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
623    : public integral_constant<bool, __is_class(_Tp)> {};
624
625#else
626
627namespace __is_class_imp
628{
629template <class _Tp> char  __test(int _Tp::*);
630template <class _Tp> __two __test(...);
631}
632
633template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
634    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
635
636#endif
637
638#if _LIBCPP_STD_VER > 14
639template <class _Tp>
640inline constexpr bool is_class_v = is_class<_Tp>::value;
641#endif
642
643// is_member_pointer
644
645#if __has_keyword(__is_member_pointer)
646
647template<class _Tp>
648struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
649
650#if _LIBCPP_STD_VER > 14
651template <class _Tp>
652inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
653#endif
654
655#else // __has_keyword(__is_member_pointer)
656
657template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
658 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
659
660#if _LIBCPP_STD_VER > 14
661template <class _Tp>
662inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
663#endif
664
665#endif // __has_keyword(__is_member_pointer)
666
667// is_enum
668
669#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
670
671template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
672    : public integral_constant<bool, __is_enum(_Tp)> {};
673
674#if _LIBCPP_STD_VER > 14
675template <class _Tp>
676inline constexpr bool is_enum_v = __is_enum(_Tp);
677#endif
678
679#else
680
681template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
682    : public integral_constant<bool, !is_void<_Tp>::value             &&
683                                     !is_integral<_Tp>::value         &&
684                                     !is_floating_point<_Tp>::value   &&
685                                     !is_array<_Tp>::value            &&
686                                     !is_pointer<_Tp>::value          &&
687                                     !is_reference<_Tp>::value        &&
688                                     !is_member_pointer<_Tp>::value   &&
689                                     !is_union<_Tp>::value            &&
690                                     !is_class<_Tp>::value            &&
691                                     !is_function<_Tp>::value         > {};
692
693#if _LIBCPP_STD_VER > 14
694template <class _Tp>
695inline constexpr bool is_enum_v = is_enum<_Tp>::value;
696#endif
697
698#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
699
700// is_arithmetic
701
702
703template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
704    : public integral_constant<bool, is_integral<_Tp>::value      ||
705                                     is_floating_point<_Tp>::value> {};
706
707#if _LIBCPP_STD_VER > 14
708template <class _Tp>
709inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
710#endif
711
712// is_fundamental
713
714// Before Clang 10, __is_fundamental didn't work for nullptr_t.
715// In C++03 nullptr_t is library-provided but must still count as "fundamental."
716#if __has_keyword(__is_fundamental) &&                                         \
717    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
718    !defined(_LIBCPP_CXX03_LANG)
719
720template<class _Tp>
721struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
722
723#if _LIBCPP_STD_VER > 14
724template <class _Tp>
725inline constexpr bool is_fundamental_v = __is_fundamental(_Tp);
726#endif
727
728#else // __has_keyword(__is_fundamental)
729
730template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
731    : public integral_constant<bool, is_void<_Tp>::value        ||
732                                     __is_nullptr_t<_Tp>::value ||
733                                     is_arithmetic<_Tp>::value> {};
734
735#if _LIBCPP_STD_VER > 14
736template <class _Tp>
737inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
738#endif
739
740#endif // __has_keyword(__is_fundamental)
741
742// is_scalar
743
744// In C++03 nullptr_t is library-provided but must still count as "scalar."
745#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
746
747template<class _Tp>
748struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
749
750#if _LIBCPP_STD_VER > 14
751template <class _Tp>
752inline constexpr bool is_scalar_v = __is_scalar(_Tp);
753#endif
754
755#else // __has_keyword(__is_scalar)
756
757template <class _Tp> struct __is_block : false_type {};
758#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
759template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
760#endif
761
762template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
763    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
764                                     is_member_pointer<_Tp>::value ||
765                                     is_pointer<_Tp>::value        ||
766                                     __is_nullptr_t<_Tp>::value    ||
767                                     __is_block<_Tp>::value        ||
768                                     is_enum<_Tp>::value           > {};
769
770template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
771
772#if _LIBCPP_STD_VER > 14
773template <class _Tp>
774inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
775#endif
776
777#endif // __has_keyword(__is_scalar)
778
779// is_object
780
781#if __has_keyword(__is_object)
782
783template<class _Tp>
784struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
785
786#if _LIBCPP_STD_VER > 14
787template <class _Tp>
788inline constexpr bool is_object_v = __is_object(_Tp);
789#endif
790
791#else // __has_keyword(__is_object)
792
793template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
794    : public integral_constant<bool, is_scalar<_Tp>::value ||
795                                     is_array<_Tp>::value  ||
796                                     is_union<_Tp>::value  ||
797                                     is_class<_Tp>::value  > {};
798
799#if _LIBCPP_STD_VER > 14
800template <class _Tp>
801inline constexpr bool is_object_v = is_object<_Tp>::value;
802#endif
803
804#endif // __has_keyword(__is_object)
805
806// is_compound
807
808// >= 11 because in C++03 nullptr isn't actually nullptr
809#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
810
811template<class _Tp>
812struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
813
814#if _LIBCPP_STD_VER > 14
815template <class _Tp>
816inline constexpr bool is_compound_v = __is_compound(_Tp);
817#endif
818
819#else // __has_keyword(__is_compound)
820
821template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
822    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
823
824#if _LIBCPP_STD_VER > 14
825template <class _Tp>
826inline constexpr bool is_compound_v = is_compound<_Tp>::value;
827#endif
828
829#endif // __has_keyword(__is_compound)
830
831// add_const
832
833template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
834  typedef _LIBCPP_NODEBUG const _Tp type;
835};
836
837#if _LIBCPP_STD_VER > 11
838template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
839#endif
840
841// add_volatile
842
843template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
844  typedef _LIBCPP_NODEBUG volatile _Tp type;
845};
846
847#if _LIBCPP_STD_VER > 11
848template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
849#endif
850
851// add_cv
852template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
853  typedef _LIBCPP_NODEBUG const volatile _Tp type;
854};
855
856#if _LIBCPP_STD_VER > 11
857template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
858#endif
859
860// add_lvalue_reference
861
862template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp  type; };
863template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp& type; };
864
865template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
866{typedef _LIBCPP_NODEBUG typename  __add_lvalue_reference_impl<_Tp>::type type;};
867
868#if _LIBCPP_STD_VER > 11
869template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
870#endif
871
872template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp   type; };
873template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp&& type; };
874
875template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
876{typedef _LIBCPP_NODEBUG typename __add_rvalue_reference_impl<_Tp>::type type;};
877
878#if _LIBCPP_STD_VER > 11
879template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
880#endif
881
882template <class _Tp>
883struct __unconstref {
884    typedef _LIBCPP_NODEBUG typename remove_const<typename remove_reference<_Tp>::type>::type type;
885};
886
887template <class _Tp>
888using __uncvref_t _LIBCPP_NODEBUG = typename remove_cv<typename remove_reference<_Tp>::type>::type;
889
890// __is_same_uncvref
891
892template <class _Tp, class _Up>
893struct __is_same_uncvref : _IsSame<__uncvref_t<_Tp>, __uncvref_t<_Up> > {};
894
895#if _LIBCPP_STD_VER > 17
896// remove_cvref - same as __uncvref
897template <class _Tp>
898struct remove_cvref {
899    using type _LIBCPP_NODEBUG = __uncvref_t<_Tp>;
900};
901
902template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
903#endif
904
905
906struct __any
907{
908    __any(...);
909};
910
911// remove_pointer
912
913template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG _Tp type;};
914template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG _Tp type;};
915template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG _Tp type;};
916template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG _Tp type;};
917template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG _Tp type;};
918
919#if _LIBCPP_STD_VER > 11
920template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
921#endif
922
923// add_pointer
924
925// type_identity
926
927template <class _Tp>
928struct __type_identity { typedef _Tp type; };
929
930template <class _Tp>
931using __type_identity_t _LIBCPP_NODEBUG = typename __type_identity<_Tp>::type;
932
933#if _LIBCPP_STD_VER > 17
934template<class _Tp> struct type_identity { typedef _Tp type; };
935template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
936#endif
937
938// is_signed
939
940#if __has_keyword(__is_signed)
941
942template<class _Tp>
943struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
944
945#if _LIBCPP_STD_VER > 14
946template <class _Tp>
947inline constexpr bool is_signed_v = __is_signed(_Tp);
948#endif
949
950#else // __has_keyword(__is_signed)
951
952template <class _Tp, bool = is_integral<_Tp>::value>
953struct __libcpp_is_signed_impl : public _BoolConstant<(_Tp(-1) < _Tp(0))> {};
954
955template <class _Tp>
956struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
957
958template <class _Tp, bool = is_arithmetic<_Tp>::value>
959struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
960
961template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
962
963template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
964
965#if _LIBCPP_STD_VER > 14
966template <class _Tp>
967inline constexpr bool is_signed_v = is_signed<_Tp>::value;
968#endif
969
970#endif // __has_keyword(__is_signed)
971
972// is_unsigned
973
974// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
975// No currently-released version of AppleClang contains the fixed intrinsic.
976#if __has_keyword(__is_unsigned) &&                                            \
977    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
978    !defined(_LIBCPP_APPLE_CLANG_VER)
979
980template<class _Tp>
981struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
982
983#if _LIBCPP_STD_VER > 14
984template <class _Tp>
985inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
986#endif
987
988#else // __has_keyword(__is_unsigned)
989
990template <class _Tp, bool = is_integral<_Tp>::value>
991struct __libcpp_is_unsigned_impl : public _BoolConstant<(_Tp(0) < _Tp(-1))> {};
992
993template <class _Tp>
994struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
995
996template <class _Tp, bool = is_arithmetic<_Tp>::value>
997struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
998
999template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1000
1001template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1002
1003#if _LIBCPP_STD_VER > 14
1004template <class _Tp>
1005inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
1006#endif
1007
1008#endif // __has_keyword(__is_unsigned)
1009
1010// rank
1011
1012template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1013    : public integral_constant<size_t, 0> {};
1014template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1015    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1016template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1017    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1018
1019#if _LIBCPP_STD_VER > 14
1020template <class _Tp>
1021inline constexpr size_t rank_v = rank<_Tp>::value;
1022#endif
1023
1024// extent
1025
1026#if __has_keyword(__array_extent)
1027
1028template<class _Tp, size_t _Dim = 0>
1029struct _LIBCPP_TEMPLATE_VIS extent
1030    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1031
1032#if _LIBCPP_STD_VER > 14
1033template <class _Tp, unsigned _Ip = 0>
1034inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
1035#endif
1036
1037#else // __has_keyword(__array_extent)
1038
1039template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1040    : public integral_constant<size_t, 0> {};
1041template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1042    : public integral_constant<size_t, 0> {};
1043template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1044    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1045template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1046    : public integral_constant<size_t, _Np> {};
1047template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1048    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1049
1050#if _LIBCPP_STD_VER > 14
1051template <class _Tp, unsigned _Ip = 0>
1052inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
1053#endif
1054
1055#endif // __has_keyword(__array_extent)
1056
1057// remove_all_extents
1058
1059template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1060    {typedef _Tp type;};
1061template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1062    {typedef typename remove_all_extents<_Tp>::type type;};
1063template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1064    {typedef typename remove_all_extents<_Tp>::type type;};
1065
1066#if _LIBCPP_STD_VER > 11
1067template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1068#endif
1069
1070#if _LIBCPP_STD_VER > 17
1071// is_bounded_array
1072
1073template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1074template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1075
1076template <class _Tp>
1077inline constexpr
1078bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1079
1080// is_unbounded_array
1081
1082template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1083template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1084
1085template <class _Tp>
1086inline constexpr
1087bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1088#endif
1089
1090// is_abstract
1091
1092template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1093    : public integral_constant<bool, __is_abstract(_Tp)> {};
1094
1095#if _LIBCPP_STD_VER > 14
1096template <class _Tp>
1097inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
1098#endif
1099
1100// is_final
1101
1102template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1103__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1104
1105#if _LIBCPP_STD_VER > 11
1106template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1107is_final : public integral_constant<bool, __is_final(_Tp)> {};
1108#endif
1109
1110#if _LIBCPP_STD_VER > 14
1111template <class _Tp>
1112inline constexpr bool is_final_v = is_final<_Tp>::value;
1113#endif
1114
1115// is_aggregate
1116#if _LIBCPP_STD_VER > 14
1117
1118template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1119is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1120
1121template <class _Tp>
1122inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
1123
1124#endif // _LIBCPP_STD_VER > 14
1125
1126// __is_core_convertible
1127
1128// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
1129// We can't test for that, but we can test implicit convertibility by passing it
1130// to a function. Notice that __is_core_convertible<void,void> is false,
1131// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.
1132
1133template <class _Tp, class _Up, class = void>
1134struct __is_core_convertible : public false_type {};
1135
1136template <class _Tp, class _Up>
1137struct __is_core_convertible<_Tp, _Up, decltype(
1138    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
1139)> : public true_type {};
1140
1141// is_nothrow_convertible
1142
1143#if _LIBCPP_STD_VER > 17
1144
1145template <typename _Tp>
1146static void __test_noexcept(_Tp) noexcept;
1147
1148template<typename _Fm, typename _To>
1149static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
1150__is_nothrow_convertible_test();
1151
1152template <typename _Fm, typename _To>
1153struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1154{ };
1155
1156template <typename _Fm, typename _To>
1157struct is_nothrow_convertible : _Or<
1158    _And<is_void<_To>, is_void<_Fm>>,
1159    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1160>::type { };
1161
1162template <typename _Fm, typename _To>
1163inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1164
1165#endif // _LIBCPP_STD_VER > 17
1166
1167// is_empty
1168
1169#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1170
1171template <class _Tp>
1172struct _LIBCPP_TEMPLATE_VIS is_empty
1173    : public integral_constant<bool, __is_empty(_Tp)> {};
1174
1175#else  // __has_feature(is_empty)
1176
1177template <class _Tp>
1178struct __is_empty1
1179    : public _Tp
1180{
1181    double __lx;
1182};
1183
1184struct __is_empty2
1185{
1186    double __lx;
1187};
1188
1189template <class _Tp, bool = is_class<_Tp>::value>
1190struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1191
1192template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1193
1194template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1195
1196#endif // __has_feature(is_empty)
1197
1198#if _LIBCPP_STD_VER > 14
1199template <class _Tp>
1200inline constexpr bool is_empty_v = is_empty<_Tp>::value;
1201#endif
1202
1203// is_polymorphic
1204
1205#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1206
1207template <class _Tp>
1208struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1209    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1210
1211#else
1212
1213template<typename _Tp> char &__is_polymorphic_impl(
1214    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1215                       int>::type);
1216template<typename _Tp> __two &__is_polymorphic_impl(...);
1217
1218template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1219    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1220
1221#endif // __has_feature(is_polymorphic)
1222
1223#if _LIBCPP_STD_VER > 14
1224template <class _Tp>
1225inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
1226#endif
1227
1228// has_virtual_destructor
1229
1230#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1231
1232template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1233    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1234
1235#else
1236
1237template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1238    : public false_type {};
1239
1240#endif
1241
1242#if _LIBCPP_STD_VER > 14
1243template <class _Tp>
1244inline constexpr bool has_virtual_destructor_v = has_virtual_destructor<_Tp>::value;
1245#endif
1246
1247// has_unique_object_representations
1248
1249#if _LIBCPP_STD_VER > 14
1250
1251template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1252    : public integral_constant<bool,
1253       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1254
1255template <class _Tp>
1256inline constexpr bool has_unique_object_representations_v = has_unique_object_representations<_Tp>::value;
1257
1258#endif
1259
1260// alignment_of
1261
1262template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1263    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1264
1265#if _LIBCPP_STD_VER > 14
1266template <class _Tp>
1267inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
1268#endif
1269
1270// aligned_storage
1271
1272template <class _Hp, class _Tp>
1273struct __type_list
1274{
1275    typedef _Hp _Head;
1276    typedef _Tp _Tail;
1277};
1278
1279struct __nat
1280{
1281#ifndef _LIBCPP_CXX03_LANG
1282    __nat() = delete;
1283    __nat(const __nat&) = delete;
1284    __nat& operator=(const __nat&) = delete;
1285    ~__nat() = delete;
1286#endif
1287};
1288
1289template <class _Tp>
1290struct __align_type
1291{
1292    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1293    typedef _Tp type;
1294};
1295
1296struct __struct_double {long double __lx;};
1297struct __struct_double4 {double __lx[4];};
1298
1299typedef
1300    __type_list<__align_type<unsigned char>,
1301    __type_list<__align_type<unsigned short>,
1302    __type_list<__align_type<unsigned int>,
1303    __type_list<__align_type<unsigned long>,
1304    __type_list<__align_type<unsigned long long>,
1305    __type_list<__align_type<double>,
1306    __type_list<__align_type<long double>,
1307    __type_list<__align_type<__struct_double>,
1308    __type_list<__align_type<__struct_double4>,
1309    __type_list<__align_type<int*>,
1310    __nat
1311    > > > > > > > > > > __all_types;
1312
1313template <size_t _Align>
1314struct _ALIGNAS(_Align) __fallback_overaligned {};
1315
1316template <class _TL, size_t _Align> struct __find_pod;
1317
1318template <class _Hp, size_t _Align>
1319struct __find_pod<__type_list<_Hp, __nat>, _Align>
1320{
1321    typedef typename conditional<
1322                             _Align == _Hp::value,
1323                             typename _Hp::type,
1324                             __fallback_overaligned<_Align>
1325                         >::type type;
1326};
1327
1328template <class _Hp, class _Tp, size_t _Align>
1329struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1330{
1331    typedef typename conditional<
1332                             _Align == _Hp::value,
1333                             typename _Hp::type,
1334                             typename __find_pod<_Tp, _Align>::type
1335                         >::type type;
1336};
1337
1338template <class _TL, size_t _Len> struct __find_max_align;
1339
1340template <class _Hp, size_t _Len>
1341struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
1342
1343template <size_t _Len, size_t _A1, size_t _A2>
1344struct __select_align
1345{
1346private:
1347    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
1348    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
1349public:
1350    static const size_t value = _Len < __max ? __min : __max;
1351};
1352
1353template <class _Hp, class _Tp, size_t _Len>
1354struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
1355    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
1356
1357template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1358struct _LIBCPP_TEMPLATE_VIS aligned_storage
1359{
1360    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
1361    union type
1362    {
1363        _Aligner __align;
1364        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
1365    };
1366};
1367
1368#if _LIBCPP_STD_VER > 11
1369template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1370    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
1371#endif
1372
1373#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
1374template <size_t _Len>\
1375struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
1376{\
1377    struct _ALIGNAS(n) type\
1378    {\
1379        unsigned char __lx[(_Len + n - 1)/n * n];\
1380    };\
1381}
1382
1383_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
1384_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
1385_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
1386_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
1387_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
1388_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
1389_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
1390_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
1391_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
1392_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
1393_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
1394_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
1395_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
1396_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
1397// PE/COFF does not support alignment beyond 8192 (=0x2000)
1398#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
1399_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
1400#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
1401
1402#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
1403
1404
1405// aligned_union
1406
1407template <size_t _I0, size_t ..._In>
1408struct __static_max;
1409
1410template <size_t _I0>
1411struct __static_max<_I0>
1412{
1413    static const size_t value = _I0;
1414};
1415
1416template <size_t _I0, size_t _I1, size_t ..._In>
1417struct __static_max<_I0, _I1, _In...>
1418{
1419    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
1420                                             __static_max<_I1, _In...>::value;
1421};
1422
1423template <size_t _Len, class _Type0, class ..._Types>
1424struct aligned_union
1425{
1426    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
1427                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
1428    static const size_t __len = __static_max<_Len, sizeof(_Type0),
1429                                             sizeof(_Types)...>::value;
1430    typedef typename aligned_storage<__len, alignment_value>::type type;
1431};
1432
1433#if _LIBCPP_STD_VER > 11
1434template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
1435#endif
1436
1437template <class _Tp>
1438struct __numeric_type
1439{
1440   static void __test(...);
1441   static float __test(float);
1442   static double __test(char);
1443   static double __test(int);
1444   static double __test(unsigned);
1445   static double __test(long);
1446   static double __test(unsigned long);
1447   static double __test(long long);
1448   static double __test(unsigned long long);
1449   static double __test(double);
1450   static long double __test(long double);
1451
1452   typedef decltype(__test(declval<_Tp>())) type;
1453   static const bool value = _IsNotSame<type, void>::value;
1454};
1455
1456template <>
1457struct __numeric_type<void>
1458{
1459   static const bool value = true;
1460};
1461
1462// __promote
1463
1464template <class _A1, class _A2 = void, class _A3 = void,
1465          bool = __numeric_type<_A1>::value &&
1466                 __numeric_type<_A2>::value &&
1467                 __numeric_type<_A3>::value>
1468class __promote_imp
1469{
1470public:
1471    static const bool value = false;
1472};
1473
1474template <class _A1, class _A2, class _A3>
1475class __promote_imp<_A1, _A2, _A3, true>
1476{
1477private:
1478    typedef typename __promote_imp<_A1>::type __type1;
1479    typedef typename __promote_imp<_A2>::type __type2;
1480    typedef typename __promote_imp<_A3>::type __type3;
1481public:
1482    typedef decltype(__type1() + __type2() + __type3()) type;
1483    static const bool value = true;
1484};
1485
1486template <class _A1, class _A2>
1487class __promote_imp<_A1, _A2, void, true>
1488{
1489private:
1490    typedef typename __promote_imp<_A1>::type __type1;
1491    typedef typename __promote_imp<_A2>::type __type2;
1492public:
1493    typedef decltype(__type1() + __type2()) type;
1494    static const bool value = true;
1495};
1496
1497template <class _A1>
1498class __promote_imp<_A1, void, void, true>
1499{
1500public:
1501    typedef typename __numeric_type<_A1>::type type;
1502    static const bool value = true;
1503};
1504
1505template <class _A1, class _A2 = void, class _A3 = void>
1506class __promote : public __promote_imp<_A1, _A2, _A3> {};
1507
1508// make_signed / make_unsigned
1509
1510typedef
1511    __type_list<signed char,
1512    __type_list<signed short,
1513    __type_list<signed int,
1514    __type_list<signed long,
1515    __type_list<signed long long,
1516#ifndef _LIBCPP_HAS_NO_INT128
1517    __type_list<__int128_t,
1518#endif
1519    __nat
1520#ifndef _LIBCPP_HAS_NO_INT128
1521    >
1522#endif
1523    > > > > > __signed_types;
1524
1525typedef
1526    __type_list<unsigned char,
1527    __type_list<unsigned short,
1528    __type_list<unsigned int,
1529    __type_list<unsigned long,
1530    __type_list<unsigned long long,
1531#ifndef _LIBCPP_HAS_NO_INT128
1532    __type_list<__uint128_t,
1533#endif
1534    __nat
1535#ifndef _LIBCPP_HAS_NO_INT128
1536    >
1537#endif
1538    > > > > > __unsigned_types;
1539
1540template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
1541
1542template <class _Hp, class _Tp, size_t _Size>
1543struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
1544{
1545    typedef _LIBCPP_NODEBUG _Hp type;
1546};
1547
1548template <class _Hp, class _Tp, size_t _Size>
1549struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
1550{
1551    typedef _LIBCPP_NODEBUG typename __find_first<_Tp, _Size>::type type;
1552};
1553
1554template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
1555                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
1556struct __apply_cv
1557{
1558    typedef _LIBCPP_NODEBUG _Up type;
1559};
1560
1561template <class _Tp, class _Up>
1562struct __apply_cv<_Tp, _Up, true, false>
1563{
1564    typedef _LIBCPP_NODEBUG const _Up type;
1565};
1566
1567template <class _Tp, class _Up>
1568struct __apply_cv<_Tp, _Up, false, true>
1569{
1570    typedef volatile _Up type;
1571};
1572
1573template <class _Tp, class _Up>
1574struct __apply_cv<_Tp, _Up, true, true>
1575{
1576    typedef const volatile _Up type;
1577};
1578
1579template <class _Tp, class _Up>
1580struct __apply_cv<_Tp&, _Up, false, false>
1581{
1582    typedef _Up& type;
1583};
1584
1585template <class _Tp, class _Up>
1586struct __apply_cv<_Tp&, _Up, true, false>
1587{
1588    typedef const _Up& type;
1589};
1590
1591template <class _Tp, class _Up>
1592struct __apply_cv<_Tp&, _Up, false, true>
1593{
1594    typedef volatile _Up& type;
1595};
1596
1597template <class _Tp, class _Up>
1598struct __apply_cv<_Tp&, _Up, true, true>
1599{
1600    typedef const volatile _Up& type;
1601};
1602
1603template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
1604struct __make_signed {};
1605
1606template <class _Tp>
1607struct __make_signed<_Tp, true>
1608{
1609    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
1610};
1611
1612template <> struct __make_signed<bool,               true> {};
1613template <> struct __make_signed<  signed short,     true> {typedef short     type;};
1614template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
1615template <> struct __make_signed<  signed int,       true> {typedef int       type;};
1616template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
1617template <> struct __make_signed<  signed long,      true> {typedef long      type;};
1618template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
1619template <> struct __make_signed<  signed long long, true> {typedef long long type;};
1620template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
1621#ifndef _LIBCPP_HAS_NO_INT128
1622template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
1623template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
1624#endif
1625
1626template <class _Tp>
1627struct _LIBCPP_TEMPLATE_VIS make_signed
1628{
1629    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
1630};
1631
1632#if _LIBCPP_STD_VER > 11
1633template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
1634#endif
1635
1636template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
1637struct __make_unsigned {};
1638
1639template <class _Tp>
1640struct __make_unsigned<_Tp, true>
1641{
1642    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
1643};
1644
1645template <> struct __make_unsigned<bool,               true> {};
1646template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
1647template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
1648template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
1649template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
1650template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
1651template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
1652template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
1653template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
1654#ifndef _LIBCPP_HAS_NO_INT128
1655template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
1656template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
1657#endif
1658
1659template <class _Tp>
1660struct _LIBCPP_TEMPLATE_VIS make_unsigned
1661{
1662    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
1663};
1664
1665#if _LIBCPP_STD_VER > 11
1666template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
1667#endif
1668
1669#ifndef _LIBCPP_CXX03_LANG
1670template <class _Tp>
1671_LIBCPP_HIDE_FROM_ABI constexpr
1672typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
1673    return static_cast<typename make_unsigned<_Tp>::type>(__x);
1674}
1675#endif
1676
1677#if _LIBCPP_STD_VER > 14
1678template <class...> using void_t = void;
1679#endif
1680
1681#if _LIBCPP_STD_VER > 17
1682// Let COND_RES(X, Y) be:
1683template <class _Tp, class _Up>
1684using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
1685
1686template <class _Tp, class _Up, class = void>
1687struct __common_type3 {};
1688
1689// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
1690template <class _Tp, class _Up>
1691struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
1692{
1693    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
1694};
1695
1696template <class _Tp, class _Up, class = void>
1697struct __common_type2_imp : __common_type3<_Tp, _Up> {};
1698#else
1699template <class _Tp, class _Up, class = void>
1700struct __common_type2_imp {};
1701#endif
1702
1703// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
1704template <class _Tp, class _Up>
1705struct __common_type2_imp<_Tp, _Up,
1706                          typename __void_t<decltype(
1707                                            true ? declval<_Tp>() : declval<_Up>()
1708                                            )>::type>
1709{
1710  typedef _LIBCPP_NODEBUG typename decay<decltype(
1711                         true ? declval<_Tp>() : declval<_Up>()
1712                         )>::type type;
1713};
1714
1715template <class, class = void>
1716struct __common_type_impl {};
1717
1718// Clang provides variadic templates in C++03 as an extension.
1719#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
1720# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
1721template <class... _Tp>
1722struct __common_types;
1723template <class... _Tp>
1724struct _LIBCPP_TEMPLATE_VIS common_type;
1725#else
1726# define _LIBCPP_OPTIONAL_PACK(...)
1727struct __no_arg;
1728template <class _Tp, class _Up, class = __no_arg>
1729struct __common_types;
1730template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
1731          class _Unused = __no_arg>
1732struct common_type {
1733  static_assert(sizeof(_Unused) == 0,
1734                "common_type accepts at most 3 arguments in C++03");
1735};
1736#endif // _LIBCPP_CXX03_LANG
1737
1738template <class _Tp, class _Up>
1739struct __common_type_impl<
1740    __common_types<_Tp, _Up>,
1741    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
1742{
1743  typedef typename common_type<_Tp, _Up>::type type;
1744};
1745
1746template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
1747struct __common_type_impl<
1748    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
1749    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
1750    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
1751                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
1752};
1753
1754// bullet 1 - sizeof...(Tp) == 0
1755
1756template <>
1757struct _LIBCPP_TEMPLATE_VIS common_type<> {};
1758
1759// bullet 2 - sizeof...(Tp) == 1
1760
1761template <class _Tp>
1762struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
1763    : public common_type<_Tp, _Tp> {};
1764
1765// bullet 3 - sizeof...(Tp) == 2
1766
1767// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
1768template <class _Tp, class _Up>
1769struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
1770    : conditional<
1771        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
1772        __common_type2_imp<_Tp, _Up>,
1773        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
1774    >::type
1775{};
1776
1777// bullet 4 - sizeof...(Tp) > 2
1778
1779template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
1780struct _LIBCPP_TEMPLATE_VIS
1781    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
1782    : __common_type_impl<
1783          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
1784
1785#undef _LIBCPP_OPTIONAL_PACK
1786
1787#if _LIBCPP_STD_VER > 11
1788template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
1789#endif
1790
1791#if _LIBCPP_STD_VER > 11
1792// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
1793// top-level cv-qualifiers.
1794template <class _From, class _To>
1795struct __copy_cv
1796{
1797    using type = _To;
1798};
1799
1800template <class _From, class _To>
1801struct __copy_cv<const _From, _To>
1802{
1803    using type = add_const_t<_To>;
1804};
1805
1806template <class _From, class _To>
1807struct __copy_cv<volatile _From, _To>
1808{
1809    using type = add_volatile_t<_To>;
1810};
1811
1812template <class _From, class _To>
1813struct __copy_cv<const volatile _From, _To>
1814{
1815    using type = add_cv_t<_To>;
1816};
1817
1818template <class _From, class _To>
1819using __copy_cv_t = typename __copy_cv<_From, _To>::type;
1820
1821template <class _From, class _To>
1822struct __copy_cvref
1823{
1824    using type = __copy_cv_t<_From, _To>;
1825};
1826
1827template <class _From, class _To>
1828struct __copy_cvref<_From&, _To>
1829{
1830    using type = add_lvalue_reference_t<__copy_cv_t<_From, _To>>;
1831};
1832
1833template <class _From, class _To>
1834struct __copy_cvref<_From&&, _To>
1835{
1836    using type = add_rvalue_reference_t<__copy_cv_t<_From, _To>>;
1837};
1838
1839template <class _From, class _To>
1840using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
1841
1842#endif // _LIBCPP_STD_VER > 11
1843
1844// common_reference
1845#if _LIBCPP_STD_VER > 17
1846// Let COND_RES(X, Y) be:
1847template <class _Xp, class _Yp>
1848using __cond_res =
1849    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
1850
1851// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
1852// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
1853// `U`.
1854// [Note: `XREF(A)` is `__xref<A>::template __apply`]
1855template <class _Tp>
1856struct __xref {
1857  template<class _Up>
1858  using __apply = __copy_cvref_t<_Tp, _Up>;
1859};
1860
1861// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
1862// and let COMMON-REF(A, B) be:
1863template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
1864struct __common_ref;
1865
1866template<class _Xp, class _Yp>
1867using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
1868
1869template<class _Xp, class _Yp>
1870using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
1871
1872
1873//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
1874//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
1875template<class _Ap, class _Bp, class _Xp, class _Yp>
1876requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
1877struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
1878{
1879    using __type = __cv_cond_res<_Xp, _Yp>;
1880};
1881
1882//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
1883template <class _Xp, class _Yp>
1884using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
1885
1886
1887//    .... If A and B are both rvalue reference types, C is well-formed, and
1888//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
1889template<class _Ap, class _Bp, class _Xp, class _Yp>
1890requires
1891  requires { typename __common_ref_C<_Xp, _Yp>; } &&
1892  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
1893  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
1894struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
1895{
1896    using __type = __common_ref_C<_Xp, _Yp>;
1897};
1898
1899//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
1900template <class _Tp, class _Up>
1901using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
1902
1903//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
1904//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
1905template<class _Ap, class _Bp, class _Xp, class _Yp>
1906requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
1907         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
1908struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
1909{
1910    using __type = __common_ref_D<_Xp, _Yp>;
1911};
1912
1913//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
1914//    COMMON-REF(A, B) is COMMON-REF(B, A).
1915template<class _Ap, class _Bp, class _Xp, class _Yp>
1916struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
1917
1918//    Otherwise, COMMON-REF(A, B) is ill-formed.
1919template<class _Ap, class _Bp, class _Xp, class _Yp>
1920struct __common_ref {};
1921
1922// Note C: For the common_reference trait applied to a parameter pack [...]
1923
1924template <class...>
1925struct common_reference;
1926
1927template <class... _Types>
1928using common_reference_t = typename common_reference<_Types...>::type;
1929
1930// bullet 1 - sizeof...(T) == 0
1931template<>
1932struct common_reference<> {};
1933
1934// bullet 2 - sizeof...(T) == 1
1935template <class _Tp>
1936struct common_reference<_Tp>
1937{
1938    using type = _Tp;
1939};
1940
1941// bullet 3 - sizeof...(T) == 2
1942template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
1943template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
1944template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
1945
1946// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
1947// the member typedef `type` denotes that type.
1948template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
1949
1950template <class _Tp, class _Up>
1951requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
1952struct __common_reference_sub_bullet1<_Tp, _Up>
1953{
1954    using type = __common_ref_t<_Tp, _Up>;
1955};
1956
1957// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
1958// is well-formed, then the member typedef `type` denotes that type.
1959template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
1960
1961template <class _Tp, class _Up>
1962using __basic_common_reference_t = typename basic_common_reference<
1963    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
1964    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
1965
1966template <class _Tp, class _Up>
1967requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
1968struct __common_reference_sub_bullet2<_Tp, _Up>
1969{
1970    using type = __basic_common_reference_t<_Tp, _Up>;
1971};
1972
1973// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
1974// then the member typedef `type` denotes that type.
1975template <class _Tp, class _Up>
1976requires requires { typename __cond_res<_Tp, _Up>; }
1977struct __common_reference_sub_bullet3<_Tp, _Up>
1978{
1979    using type = __cond_res<_Tp, _Up>;
1980};
1981
1982
1983// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
1984//                    then the member typedef `type` denotes that type.
1985//                  - Otherwise, there shall be no member `type`.
1986template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
1987
1988// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
1989//            any, as `common_reference_t<C, Rest...>`.
1990template <class _Tp, class _Up, class _Vp, class... _Rest>
1991requires requires { typename common_reference_t<_Tp, _Up>; }
1992struct common_reference<_Tp, _Up, _Vp, _Rest...>
1993    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
1994{};
1995
1996// bullet 5 - Otherwise, there shall be no member `type`.
1997template <class...> struct common_reference {};
1998
1999#endif // _LIBCPP_STD_VER > 17
2000
2001// is_assignable
2002
2003template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG _Tp type; };
2004
2005#if __has_keyword(__is_assignable)
2006
2007template<class _Tp, class _Up>
2008struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2009
2010#if _LIBCPP_STD_VER > 14
2011template <class _Tp, class _Arg>
2012inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Arg);
2013#endif
2014
2015#else // __has_keyword(__is_assignable)
2016
2017template <class _Tp, class _Arg>
2018typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
2019__is_assignable_test(int);
2020
2021template <class, class>
2022false_type __is_assignable_test(...);
2023
2024
2025template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2026struct __is_assignable_imp
2027    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2028
2029template <class _Tp, class _Arg>
2030struct __is_assignable_imp<_Tp, _Arg, true>
2031    : public false_type
2032{
2033};
2034
2035template <class _Tp, class _Arg>
2036struct is_assignable
2037    : public __is_assignable_imp<_Tp, _Arg> {};
2038
2039#if _LIBCPP_STD_VER > 14
2040template <class _Tp, class _Arg>
2041inline constexpr bool is_assignable_v = is_assignable<_Tp, _Arg>::value;
2042#endif
2043
2044#endif // __has_keyword(__is_assignable)
2045
2046// is_copy_assignable
2047
2048template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2049    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2050                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2051
2052#if _LIBCPP_STD_VER > 14
2053template <class _Tp>
2054inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
2055#endif
2056
2057// is_move_assignable
2058
2059template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2060    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2061                           typename add_rvalue_reference<_Tp>::type> {};
2062
2063#if _LIBCPP_STD_VER > 14
2064template <class _Tp>
2065inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
2066#endif
2067
2068// is_destructible
2069
2070#if __has_keyword(__is_destructible)
2071
2072template<class _Tp>
2073struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2074
2075#if _LIBCPP_STD_VER > 14
2076template <class _Tp>
2077inline constexpr bool is_destructible_v = __is_destructible(_Tp);
2078#endif
2079
2080#else // __has_keyword(__is_destructible)
2081
2082//  if it's a reference, return true
2083//  if it's a function, return false
2084//  if it's   void,     return false
2085//  if it's an array of unknown bound, return false
2086//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
2087//    where _Up is remove_all_extents<_Tp>::type
2088
2089template <class>
2090struct __is_destructible_apply { typedef int type; };
2091
2092template <typename _Tp>
2093struct __is_destructor_wellformed {
2094    template <typename _Tp1>
2095    static char  __test (
2096        typename __is_destructible_apply<decltype(declval<_Tp1&>().~_Tp1())>::type
2097    );
2098
2099    template <typename _Tp1>
2100    static __two __test (...);
2101
2102    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2103};
2104
2105template <class _Tp, bool>
2106struct __destructible_imp;
2107
2108template <class _Tp>
2109struct __destructible_imp<_Tp, false>
2110   : public integral_constant<bool,
2111        __is_destructor_wellformed<typename remove_all_extents<_Tp>::type>::value> {};
2112
2113template <class _Tp>
2114struct __destructible_imp<_Tp, true>
2115    : public true_type {};
2116
2117template <class _Tp, bool>
2118struct __destructible_false;
2119
2120template <class _Tp>
2121struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, is_reference<_Tp>::value> {};
2122
2123template <class _Tp>
2124struct __destructible_false<_Tp, true> : public false_type {};
2125
2126template <class _Tp>
2127struct is_destructible
2128    : public __destructible_false<_Tp, is_function<_Tp>::value> {};
2129
2130template <class _Tp>
2131struct is_destructible<_Tp[]>
2132    : public false_type {};
2133
2134template <>
2135struct is_destructible<void>
2136    : public false_type {};
2137
2138#if _LIBCPP_STD_VER > 14
2139template <class _Tp>
2140inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
2141#endif
2142
2143#endif // __has_keyword(__is_destructible)
2144
2145template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2146struct __member_pointer_traits_imp
2147{
2148};
2149
2150template <class _Rp, class _Class, class ..._Param>
2151struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2152{
2153    typedef _Class _ClassType;
2154    typedef _Rp _ReturnType;
2155    typedef _Rp (_FnType) (_Param...);
2156};
2157
2158template <class _Rp, class _Class, class ..._Param>
2159struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2160{
2161    typedef _Class _ClassType;
2162    typedef _Rp _ReturnType;
2163    typedef _Rp (_FnType) (_Param..., ...);
2164};
2165
2166template <class _Rp, class _Class, class ..._Param>
2167struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2168{
2169    typedef _Class const _ClassType;
2170    typedef _Rp _ReturnType;
2171    typedef _Rp (_FnType) (_Param...);
2172};
2173
2174template <class _Rp, class _Class, class ..._Param>
2175struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2176{
2177    typedef _Class const _ClassType;
2178    typedef _Rp _ReturnType;
2179    typedef _Rp (_FnType) (_Param..., ...);
2180};
2181
2182template <class _Rp, class _Class, class ..._Param>
2183struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2184{
2185    typedef _Class volatile _ClassType;
2186    typedef _Rp _ReturnType;
2187    typedef _Rp (_FnType) (_Param...);
2188};
2189
2190template <class _Rp, class _Class, class ..._Param>
2191struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2192{
2193    typedef _Class volatile _ClassType;
2194    typedef _Rp _ReturnType;
2195    typedef _Rp (_FnType) (_Param..., ...);
2196};
2197
2198template <class _Rp, class _Class, class ..._Param>
2199struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2200{
2201    typedef _Class const volatile _ClassType;
2202    typedef _Rp _ReturnType;
2203    typedef _Rp (_FnType) (_Param...);
2204};
2205
2206template <class _Rp, class _Class, class ..._Param>
2207struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2208{
2209    typedef _Class const volatile _ClassType;
2210    typedef _Rp _ReturnType;
2211    typedef _Rp (_FnType) (_Param..., ...);
2212};
2213
2214#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2215
2216template <class _Rp, class _Class, class ..._Param>
2217struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2218{
2219    typedef _Class& _ClassType;
2220    typedef _Rp _ReturnType;
2221    typedef _Rp (_FnType) (_Param...);
2222};
2223
2224template <class _Rp, class _Class, class ..._Param>
2225struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2226{
2227    typedef _Class& _ClassType;
2228    typedef _Rp _ReturnType;
2229    typedef _Rp (_FnType) (_Param..., ...);
2230};
2231
2232template <class _Rp, class _Class, class ..._Param>
2233struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2234{
2235    typedef _Class const& _ClassType;
2236    typedef _Rp _ReturnType;
2237    typedef _Rp (_FnType) (_Param...);
2238};
2239
2240template <class _Rp, class _Class, class ..._Param>
2241struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2242{
2243    typedef _Class const& _ClassType;
2244    typedef _Rp _ReturnType;
2245    typedef _Rp (_FnType) (_Param..., ...);
2246};
2247
2248template <class _Rp, class _Class, class ..._Param>
2249struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2250{
2251    typedef _Class volatile& _ClassType;
2252    typedef _Rp _ReturnType;
2253    typedef _Rp (_FnType) (_Param...);
2254};
2255
2256template <class _Rp, class _Class, class ..._Param>
2257struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2258{
2259    typedef _Class volatile& _ClassType;
2260    typedef _Rp _ReturnType;
2261    typedef _Rp (_FnType) (_Param..., ...);
2262};
2263
2264template <class _Rp, class _Class, class ..._Param>
2265struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2266{
2267    typedef _Class const volatile& _ClassType;
2268    typedef _Rp _ReturnType;
2269    typedef _Rp (_FnType) (_Param...);
2270};
2271
2272template <class _Rp, class _Class, class ..._Param>
2273struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2274{
2275    typedef _Class const volatile& _ClassType;
2276    typedef _Rp _ReturnType;
2277    typedef _Rp (_FnType) (_Param..., ...);
2278};
2279
2280template <class _Rp, class _Class, class ..._Param>
2281struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2282{
2283    typedef _Class&& _ClassType;
2284    typedef _Rp _ReturnType;
2285    typedef _Rp (_FnType) (_Param...);
2286};
2287
2288template <class _Rp, class _Class, class ..._Param>
2289struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2290{
2291    typedef _Class&& _ClassType;
2292    typedef _Rp _ReturnType;
2293    typedef _Rp (_FnType) (_Param..., ...);
2294};
2295
2296template <class _Rp, class _Class, class ..._Param>
2297struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2298{
2299    typedef _Class const&& _ClassType;
2300    typedef _Rp _ReturnType;
2301    typedef _Rp (_FnType) (_Param...);
2302};
2303
2304template <class _Rp, class _Class, class ..._Param>
2305struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2306{
2307    typedef _Class const&& _ClassType;
2308    typedef _Rp _ReturnType;
2309    typedef _Rp (_FnType) (_Param..., ...);
2310};
2311
2312template <class _Rp, class _Class, class ..._Param>
2313struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2314{
2315    typedef _Class volatile&& _ClassType;
2316    typedef _Rp _ReturnType;
2317    typedef _Rp (_FnType) (_Param...);
2318};
2319
2320template <class _Rp, class _Class, class ..._Param>
2321struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2322{
2323    typedef _Class volatile&& _ClassType;
2324    typedef _Rp _ReturnType;
2325    typedef _Rp (_FnType) (_Param..., ...);
2326};
2327
2328template <class _Rp, class _Class, class ..._Param>
2329struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2330{
2331    typedef _Class const volatile&& _ClassType;
2332    typedef _Rp _ReturnType;
2333    typedef _Rp (_FnType) (_Param...);
2334};
2335
2336template <class _Rp, class _Class, class ..._Param>
2337struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2338{
2339    typedef _Class const volatile&& _ClassType;
2340    typedef _Rp _ReturnType;
2341    typedef _Rp (_FnType) (_Param..., ...);
2342};
2343
2344#endif // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2345
2346
2347template <class _Rp, class _Class>
2348struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2349{
2350    typedef _Class _ClassType;
2351    typedef _Rp _ReturnType;
2352};
2353
2354template <class _MP>
2355struct __member_pointer_traits
2356    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2357                    is_member_function_pointer<_MP>::value,
2358                    is_member_object_pointer<_MP>::value>
2359{
2360//     typedef ... _ClassType;
2361//     typedef ... _ReturnType;
2362//     typedef ... _FnType;
2363};
2364
2365
2366template <class _DecayedFp>
2367struct __member_pointer_class_type {};
2368
2369template <class _Ret, class _ClassType>
2370struct __member_pointer_class_type<_Ret _ClassType::*> {
2371  typedef _ClassType type;
2372};
2373
2374// template <class T, class... Args> struct is_constructible;
2375
2376template <class _Tp, class ..._Args>
2377struct _LIBCPP_TEMPLATE_VIS is_constructible
2378    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
2379{ };
2380
2381#if _LIBCPP_STD_VER > 14
2382template <class _Tp, class ..._Args>
2383inline constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
2384#endif
2385
2386// is_default_constructible
2387
2388template <class _Tp>
2389struct _LIBCPP_TEMPLATE_VIS is_default_constructible
2390    : public is_constructible<_Tp>
2391    {};
2392
2393#if _LIBCPP_STD_VER > 14
2394template <class _Tp>
2395inline constexpr bool is_default_constructible_v = is_default_constructible<_Tp>::value;
2396#endif
2397
2398#ifndef _LIBCPP_CXX03_LANG
2399// First of all, we can't implement this check in C++03 mode because the {}
2400// default initialization syntax isn't valid.
2401// Second, we implement the trait in a funny manner with two defaulted template
2402// arguments to workaround Clang's PR43454.
2403template <class _Tp>
2404void __test_implicit_default_constructible(_Tp);
2405
2406template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
2407struct __is_implicitly_default_constructible
2408    : false_type
2409{ };
2410
2411template <class _Tp>
2412struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
2413    : true_type
2414{ };
2415
2416template <class _Tp>
2417struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
2418    : false_type
2419{ };
2420#endif // !C++03
2421
2422// is_copy_constructible
2423
2424template <class _Tp>
2425struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
2426    : public is_constructible<_Tp,
2427                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2428
2429#if _LIBCPP_STD_VER > 14
2430template <class _Tp>
2431inline constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
2432#endif
2433
2434// is_move_constructible
2435
2436template <class _Tp>
2437struct _LIBCPP_TEMPLATE_VIS is_move_constructible
2438    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
2439    {};
2440
2441#if _LIBCPP_STD_VER > 14
2442template <class _Tp>
2443inline constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
2444#endif
2445
2446// is_trivially_constructible
2447
2448template <class _Tp, class... _Args>
2449struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
2450    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
2451{
2452};
2453
2454#if _LIBCPP_STD_VER > 14
2455template <class _Tp, class... _Args>
2456inline constexpr bool is_trivially_constructible_v = is_trivially_constructible<_Tp, _Args...>::value;
2457#endif
2458
2459// is_trivially_default_constructible
2460
2461template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
2462    : public is_trivially_constructible<_Tp>
2463    {};
2464
2465#if _LIBCPP_STD_VER > 14
2466template <class _Tp>
2467inline constexpr bool is_trivially_default_constructible_v = is_trivially_default_constructible<_Tp>::value;
2468#endif
2469
2470// is_trivially_copy_constructible
2471
2472template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
2473    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
2474    {};
2475
2476#if _LIBCPP_STD_VER > 14
2477template <class _Tp>
2478inline constexpr bool is_trivially_copy_constructible_v = is_trivially_copy_constructible<_Tp>::value;
2479#endif
2480
2481// is_trivially_move_constructible
2482
2483template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
2484    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
2485    {};
2486
2487#if _LIBCPP_STD_VER > 14
2488template <class _Tp>
2489inline constexpr bool is_trivially_move_constructible_v = is_trivially_move_constructible<_Tp>::value;
2490#endif
2491
2492// is_trivially_assignable
2493
2494template <class _Tp, class _Arg>
2495struct is_trivially_assignable
2496    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
2497{ };
2498
2499#if _LIBCPP_STD_VER > 14
2500template <class _Tp, class _Arg>
2501inline constexpr bool is_trivially_assignable_v = is_trivially_assignable<_Tp, _Arg>::value;
2502#endif
2503
2504// is_trivially_copy_assignable
2505
2506template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
2507    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
2508                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2509
2510#if _LIBCPP_STD_VER > 14
2511template <class _Tp>
2512inline constexpr bool is_trivially_copy_assignable_v = is_trivially_copy_assignable<_Tp>::value;
2513#endif
2514
2515// is_trivially_move_assignable
2516
2517template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
2518    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
2519                                     typename add_rvalue_reference<_Tp>::type>
2520    {};
2521
2522#if _LIBCPP_STD_VER > 14
2523template <class _Tp>
2524inline constexpr bool is_trivially_move_assignable_v = is_trivially_move_assignable<_Tp>::value;
2525#endif
2526
2527// is_trivially_destructible
2528
2529#if __has_keyword(__is_trivially_destructible)
2530
2531template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
2532    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
2533
2534#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
2535
2536template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
2537    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
2538
2539#else
2540
2541template <class _Tp> struct __libcpp_trivial_destructor
2542    : public integral_constant<bool, is_scalar<_Tp>::value ||
2543                                     is_reference<_Tp>::value> {};
2544
2545template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
2546    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
2547
2548template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
2549    : public false_type {};
2550
2551#endif
2552
2553#if _LIBCPP_STD_VER > 14
2554template <class _Tp>
2555inline constexpr bool is_trivially_destructible_v = is_trivially_destructible<_Tp>::value;
2556#endif
2557
2558// is_nothrow_constructible
2559
2560#if __has_keyword(__is_nothrow_constructible)
2561
2562template <class _Tp, class... _Args>
2563struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
2564    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
2565
2566#else
2567
2568template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
2569
2570template <class _Tp, class... _Args>
2571struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
2572    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
2573{
2574};
2575
2576template <class _Tp>
2577void __implicit_conversion_to(_Tp) noexcept { }
2578
2579template <class _Tp, class _Arg>
2580struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
2581    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
2582{
2583};
2584
2585template <class _Tp, bool _IsReference, class... _Args>
2586struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
2587    : public false_type
2588{
2589};
2590
2591template <class _Tp, class... _Args>
2592struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
2593    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
2594{
2595};
2596
2597template <class _Tp, size_t _Ns>
2598struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
2599    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
2600{
2601};
2602
2603#endif // _LIBCPP_HAS_NO_NOEXCEPT
2604
2605
2606#if _LIBCPP_STD_VER > 14
2607template <class _Tp, class ..._Args>
2608inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
2609#endif
2610
2611// is_nothrow_default_constructible
2612
2613template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
2614    : public is_nothrow_constructible<_Tp>
2615    {};
2616
2617#if _LIBCPP_STD_VER > 14
2618template <class _Tp>
2619inline constexpr bool is_nothrow_default_constructible_v = is_nothrow_default_constructible<_Tp>::value;
2620#endif
2621
2622// is_nothrow_copy_constructible
2623
2624template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
2625    : public is_nothrow_constructible<_Tp,
2626                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2627
2628#if _LIBCPP_STD_VER > 14
2629template <class _Tp>
2630inline constexpr bool is_nothrow_copy_constructible_v = is_nothrow_copy_constructible<_Tp>::value;
2631#endif
2632
2633// is_nothrow_move_constructible
2634
2635template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
2636    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
2637    {};
2638
2639#if _LIBCPP_STD_VER > 14
2640template <class _Tp>
2641inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<_Tp>::value;
2642#endif
2643
2644// is_nothrow_assignable
2645
2646#if __has_keyword(__is_nothrow_assignable)
2647
2648template <class _Tp, class _Arg>
2649struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
2650    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
2651
2652#else
2653
2654template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
2655
2656template <class _Tp, class _Arg>
2657struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
2658    : public false_type
2659{
2660};
2661
2662template <class _Tp, class _Arg>
2663struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
2664    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
2665{
2666};
2667
2668template <class _Tp, class _Arg>
2669struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
2670    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
2671{
2672};
2673
2674#endif // _LIBCPP_HAS_NO_NOEXCEPT
2675
2676#if _LIBCPP_STD_VER > 14
2677template <class _Tp, class _Arg>
2678inline constexpr bool is_nothrow_assignable_v = is_nothrow_assignable<_Tp, _Arg>::value;
2679#endif
2680
2681// is_nothrow_copy_assignable
2682
2683template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
2684    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
2685                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2686
2687#if _LIBCPP_STD_VER > 14
2688template <class _Tp>
2689inline constexpr bool is_nothrow_copy_assignable_v = is_nothrow_copy_assignable<_Tp>::value;
2690#endif
2691
2692// is_nothrow_move_assignable
2693
2694template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
2695    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
2696                                     typename add_rvalue_reference<_Tp>::type>
2697    {};
2698
2699#if _LIBCPP_STD_VER > 14
2700template <class _Tp>
2701inline constexpr bool is_nothrow_move_assignable_v = is_nothrow_move_assignable<_Tp>::value;
2702#endif
2703
2704// is_nothrow_destructible
2705
2706#if !defined(_LIBCPP_CXX03_LANG)
2707
2708template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
2709
2710template <class _Tp>
2711struct __libcpp_is_nothrow_destructible<false, _Tp>
2712    : public false_type
2713{
2714};
2715
2716template <class _Tp>
2717struct __libcpp_is_nothrow_destructible<true, _Tp>
2718    : public integral_constant<bool, noexcept(declval<_Tp>().~_Tp()) >
2719{
2720};
2721
2722template <class _Tp>
2723struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
2724    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
2725{
2726};
2727
2728template <class _Tp, size_t _Ns>
2729struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
2730    : public is_nothrow_destructible<_Tp>
2731{
2732};
2733
2734template <class _Tp>
2735struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
2736    : public true_type
2737{
2738};
2739
2740template <class _Tp>
2741struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
2742    : public true_type
2743{
2744};
2745
2746#else
2747
2748template <class _Tp> struct __libcpp_nothrow_destructor
2749    : public integral_constant<bool, is_scalar<_Tp>::value ||
2750                                     is_reference<_Tp>::value> {};
2751
2752template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
2753    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
2754
2755template <class _Tp>
2756struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
2757    : public false_type {};
2758
2759#endif
2760
2761#if _LIBCPP_STD_VER > 14
2762template <class _Tp>
2763inline constexpr bool is_nothrow_destructible_v = is_nothrow_destructible<_Tp>::value;
2764#endif
2765
2766// is_pod
2767
2768#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
2769
2770template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
2771    : public integral_constant<bool, __is_pod(_Tp)> {};
2772
2773#else
2774
2775template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
2776    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
2777                                     is_trivially_copy_constructible<_Tp>::value      &&
2778                                     is_trivially_copy_assignable<_Tp>::value    &&
2779                                     is_trivially_destructible<_Tp>::value> {};
2780
2781#endif
2782
2783#if _LIBCPP_STD_VER > 14
2784template <class _Tp>
2785inline constexpr bool is_pod_v = is_pod<_Tp>::value;
2786#endif
2787
2788// is_literal_type;
2789
2790#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
2791template <class _Tp> struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 is_literal_type
2792    : public integral_constant<bool, __is_literal_type(_Tp)>
2793    {};
2794
2795#if _LIBCPP_STD_VER > 14
2796template <class _Tp>
2797_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
2798#endif // _LIBCPP_STD_VER > 14
2799#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
2800
2801// is_standard_layout;
2802
2803template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
2804#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
2805    : public integral_constant<bool, __is_standard_layout(_Tp)>
2806#else
2807    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
2808#endif
2809    {};
2810
2811#if _LIBCPP_STD_VER > 14
2812template <class _Tp>
2813inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
2814#endif
2815
2816// is_trivially_copyable;
2817
2818template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
2819    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
2820    {};
2821
2822#if _LIBCPP_STD_VER > 14
2823template <class _Tp>
2824inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
2825#endif
2826
2827// is_trivial;
2828
2829template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
2830#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
2831    : public integral_constant<bool, __is_trivial(_Tp)>
2832#else
2833    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
2834                                 is_trivially_default_constructible<_Tp>::value>
2835#endif
2836    {};
2837
2838#if _LIBCPP_STD_VER > 14
2839template <class _Tp>
2840inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
2841#endif
2842
2843
2844#ifndef _LIBCPP_CXX03_LANG
2845
2846template <class _Fp, class _A0,
2847         class _DecayFp = typename decay<_Fp>::type,
2848         class _DecayA0 = typename decay<_A0>::type,
2849         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
2850using __enable_if_bullet1 = typename enable_if
2851    <
2852        is_member_function_pointer<_DecayFp>::value
2853        && is_base_of<_ClassT, _DecayA0>::value
2854    >::type;
2855
2856template <class _Fp, class _A0,
2857         class _DecayFp = typename decay<_Fp>::type,
2858         class _DecayA0 = typename decay<_A0>::type>
2859using __enable_if_bullet2 = typename enable_if
2860    <
2861        is_member_function_pointer<_DecayFp>::value
2862        && __is_reference_wrapper<_DecayA0>::value
2863    >::type;
2864
2865template <class _Fp, class _A0,
2866         class _DecayFp = typename decay<_Fp>::type,
2867         class _DecayA0 = typename decay<_A0>::type,
2868         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
2869using __enable_if_bullet3 = typename enable_if
2870    <
2871        is_member_function_pointer<_DecayFp>::value
2872        && !is_base_of<_ClassT, _DecayA0>::value
2873        && !__is_reference_wrapper<_DecayA0>::value
2874    >::type;
2875
2876template <class _Fp, class _A0,
2877         class _DecayFp = typename decay<_Fp>::type,
2878         class _DecayA0 = typename decay<_A0>::type,
2879         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
2880using __enable_if_bullet4 = typename enable_if
2881    <
2882        is_member_object_pointer<_DecayFp>::value
2883        && is_base_of<_ClassT, _DecayA0>::value
2884    >::type;
2885
2886template <class _Fp, class _A0,
2887         class _DecayFp = typename decay<_Fp>::type,
2888         class _DecayA0 = typename decay<_A0>::type>
2889using __enable_if_bullet5 = typename enable_if
2890    <
2891        is_member_object_pointer<_DecayFp>::value
2892        && __is_reference_wrapper<_DecayA0>::value
2893    >::type;
2894
2895template <class _Fp, class _A0,
2896         class _DecayFp = typename decay<_Fp>::type,
2897         class _DecayA0 = typename decay<_A0>::type,
2898         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
2899using __enable_if_bullet6 = typename enable_if
2900    <
2901        is_member_object_pointer<_DecayFp>::value
2902        && !is_base_of<_ClassT, _DecayA0>::value
2903        && !__is_reference_wrapper<_DecayA0>::value
2904    >::type;
2905
2906// __invoke forward declarations
2907
2908// fall back - none of the bullets
2909
2910template <class ..._Args>
2911auto __invoke(__any, _Args&& ...__args) -> __nat;
2912
2913// bullets 1, 2 and 3
2914
2915template <class _Fp, class _A0, class ..._Args,
2916          class = __enable_if_bullet1<_Fp, _A0>>
2917inline _LIBCPP_INLINE_VISIBILITY
2918constexpr auto
2919__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
2920    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
2921    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
2922    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
2923
2924template <class _Fp, class _A0, class ..._Args,
2925          class = __enable_if_bullet2<_Fp, _A0>>
2926inline _LIBCPP_INLINE_VISIBILITY
2927constexpr auto
2928__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
2929    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
2930    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
2931    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
2932
2933template <class _Fp, class _A0, class ..._Args,
2934          class = __enable_if_bullet3<_Fp, _A0>>
2935inline _LIBCPP_INLINE_VISIBILITY
2936constexpr auto
2937__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
2938    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
2939    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
2940    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
2941
2942// bullets 4, 5 and 6
2943
2944template <class _Fp, class _A0,
2945          class = __enable_if_bullet4<_Fp, _A0>>
2946inline _LIBCPP_INLINE_VISIBILITY
2947constexpr auto
2948__invoke(_Fp&& __f, _A0&& __a0)
2949    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
2950    -> decltype(      static_cast<_A0&&>(__a0).*__f)
2951    { return          static_cast<_A0&&>(__a0).*__f; }
2952
2953template <class _Fp, class _A0,
2954          class = __enable_if_bullet5<_Fp, _A0>>
2955inline _LIBCPP_INLINE_VISIBILITY
2956constexpr auto
2957__invoke(_Fp&& __f, _A0&& __a0)
2958    noexcept(noexcept(__a0.get().*__f))
2959    -> decltype(      __a0.get().*__f)
2960    { return          __a0.get().*__f; }
2961
2962template <class _Fp, class _A0,
2963          class = __enable_if_bullet6<_Fp, _A0>>
2964inline _LIBCPP_INLINE_VISIBILITY
2965constexpr auto
2966__invoke(_Fp&& __f, _A0&& __a0)
2967    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
2968    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
2969    { return          (*static_cast<_A0&&>(__a0)).*__f; }
2970
2971// bullet 7
2972
2973template <class _Fp, class ..._Args>
2974inline _LIBCPP_INLINE_VISIBILITY
2975constexpr auto
2976__invoke(_Fp&& __f, _Args&& ...__args)
2977    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
2978    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
2979    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
2980
2981// __invokable
2982template <class _Ret, class _Fp, class ..._Args>
2983struct __invokable_r
2984{
2985  template <class _XFp, class ..._XArgs>
2986  static auto __try_call(int) -> decltype(
2987    _VSTD::__invoke(declval<_XFp>(), declval<_XArgs>()...));
2988  template <class _XFp, class ..._XArgs>
2989  static __nat __try_call(...);
2990
2991  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
2992  // or incomplete array types as required by the standard.
2993  using _Result = decltype(__try_call<_Fp, _Args...>(0));
2994
2995  using type = typename conditional<
2996      _IsNotSame<_Result, __nat>::value,
2997      typename conditional< is_void<_Ret>::value, true_type, __is_core_convertible<_Result, _Ret> >::type,
2998      false_type >::type;
2999  static const bool value = type::value;
3000};
3001template <class _Fp, class ..._Args>
3002using __invokable = __invokable_r<void, _Fp, _Args...>;
3003
3004template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3005struct __nothrow_invokable_r_imp {
3006  static const bool value = false;
3007};
3008
3009template <class _Ret, class _Fp, class ..._Args>
3010struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3011{
3012    typedef __nothrow_invokable_r_imp _ThisT;
3013
3014    template <class _Tp>
3015    static void __test_noexcept(_Tp) noexcept;
3016
3017    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3018        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...)));
3019};
3020
3021template <class _Ret, class _Fp, class ..._Args>
3022struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3023{
3024    static const bool value = noexcept(
3025        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...));
3026};
3027
3028template <class _Ret, class _Fp, class ..._Args>
3029using __nothrow_invokable_r =
3030    __nothrow_invokable_r_imp<
3031            __invokable_r<_Ret, _Fp, _Args...>::value,
3032            is_void<_Ret>::value,
3033            _Ret, _Fp, _Args...
3034    >;
3035
3036template <class _Fp, class ..._Args>
3037using __nothrow_invokable =
3038    __nothrow_invokable_r_imp<
3039            __invokable<_Fp, _Args...>::value,
3040            true, void, _Fp, _Args...
3041    >;
3042
3043template <class _Fp, class ..._Args>
3044struct __invoke_of
3045    : public enable_if<
3046        __invokable<_Fp, _Args...>::value,
3047        typename __invokable_r<void, _Fp, _Args...>::_Result>
3048{
3049};
3050
3051#else
3052
3053// Assume that it's a functor in C++03
3054template <class _Func, class... _Args>
3055_LIBCPP_HIDE_FROM_ABI
3056decltype(std::declval<_Func>()(std::declval<_Args>()...)) __invoke(_Func&& __func, _Args&&... __args) {
3057    return static_cast<_Func&&>(__func)(static_cast<_Args&&>(__args)...);
3058}
3059
3060#endif // _LIBCPP_CXX03_LANG
3061
3062// result_of
3063
3064#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3065template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
3066
3067#ifndef _LIBCPP_CXX03_LANG
3068
3069template <class _Fp, class ..._Args>
3070class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3071    : public __invoke_of<_Fp, _Args...>
3072{
3073};
3074
3075#else // C++03
3076
3077template <class _Fn, bool, bool>
3078class __result_of
3079{
3080};
3081
3082template <class _Fn, class ..._Args>
3083class __result_of<_Fn(_Args...), true, false>
3084{
3085public:
3086    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
3087};
3088
3089template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
3090struct __result_of_mp;
3091
3092// member function pointer
3093
3094template <class _MP, class _Tp>
3095struct __result_of_mp<_MP, _Tp, true>
3096{
3097    using type = typename __member_pointer_traits<_MP>::_ReturnType;
3098};
3099
3100// member data pointer
3101
3102template <class _MP, class _Tp, bool>
3103struct __result_of_mdp;
3104
3105template <class _Rp, class _Class, class _Tp>
3106struct __result_of_mdp<_Rp _Class::*, _Tp, false>
3107{
3108    using type = typename __apply_cv<decltype(*declval<_Tp>()), _Rp>::type&;
3109};
3110
3111template <class _Rp, class _Class, class _Tp>
3112struct __result_of_mdp<_Rp _Class::*, _Tp, true>
3113{
3114    using type = typename __apply_cv<_Tp, _Rp>::type&;
3115};
3116
3117template <class _Rp, class _Class, class _Tp>
3118struct __result_of_mp<_Rp _Class::*, _Tp, false>
3119    : public __result_of_mdp<_Rp _Class::*, _Tp,
3120            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
3121{
3122};
3123
3124template <class _Fn, class _Tp>
3125class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
3126    : public __result_of_mp<typename remove_reference<_Fn>::type,
3127                            _Tp,
3128                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3129{
3130};
3131
3132template <class _Fn, class _Tp, class ..._Args>
3133class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
3134    : public __result_of_mp<typename remove_reference<_Fn>::type,
3135                            _Tp,
3136                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3137{
3138};
3139
3140template <class _Fn, class ..._Args>
3141class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
3142    : public __result_of<_Fn(_Args...),
3143                         is_class<typename remove_reference<_Fn>::type>::value ||
3144                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3145                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3146                        >
3147{
3148};
3149
3150#endif // C++03
3151
3152#if _LIBCPP_STD_VER > 11
3153template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
3154#endif // _LIBCPP_STD_VER > 11
3155#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3156
3157#if _LIBCPP_STD_VER > 14
3158
3159// invoke_result
3160
3161template <class _Fn, class... _Args>
3162struct _LIBCPP_TEMPLATE_VIS invoke_result
3163    : __invoke_of<_Fn, _Args...>
3164{
3165};
3166
3167template <class _Fn, class... _Args>
3168using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3169
3170// is_invocable
3171
3172template <class _Fn, class ..._Args>
3173struct _LIBCPP_TEMPLATE_VIS is_invocable
3174    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
3175
3176template <class _Ret, class _Fn, class ..._Args>
3177struct _LIBCPP_TEMPLATE_VIS is_invocable_r
3178    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
3179
3180template <class _Fn, class ..._Args>
3181inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
3182
3183template <class _Ret, class _Fn, class ..._Args>
3184inline constexpr bool is_invocable_r_v = is_invocable_r<_Ret, _Fn, _Args...>::value;
3185
3186// is_nothrow_invocable
3187
3188template <class _Fn, class ..._Args>
3189struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
3190    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
3191
3192template <class _Ret, class _Fn, class ..._Args>
3193struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
3194    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
3195
3196template <class _Fn, class ..._Args>
3197inline constexpr bool is_nothrow_invocable_v = is_nothrow_invocable<_Fn, _Args...>::value;
3198
3199template <class _Ret, class _Fn, class ..._Args>
3200inline constexpr bool is_nothrow_invocable_r_v = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3201
3202#endif // _LIBCPP_STD_VER > 14
3203
3204// __swappable
3205
3206template <class _Tp> struct __is_swappable;
3207template <class _Tp> struct __is_nothrow_swappable;
3208
3209
3210#ifndef _LIBCPP_CXX03_LANG
3211template <class _Tp>
3212using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
3213#else
3214template <class>
3215using __swap_result_t = void;
3216#endif
3217
3218template <class _Tp>
3219inline _LIBCPP_INLINE_VISIBILITY
3220_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
3221swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
3222                                    is_nothrow_move_assignable<_Tp>::value);
3223
3224template<class _Tp, size_t _Np>
3225inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3226typename enable_if<
3227    __is_swappable<_Tp>::value
3228>::type
3229swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
3230
3231namespace __detail
3232{
3233// ALL generic swap overloads MUST already have a declaration available at this point.
3234
3235template <class _Tp, class _Up = _Tp,
3236          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
3237struct __swappable_with
3238{
3239    template <class _LHS, class _RHS>
3240    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
3241    __test_swap(int);
3242    template <class, class>
3243    static __nat __test_swap(long);
3244
3245    // Extra parens are needed for the C++03 definition of decltype.
3246    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
3247    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
3248
3249    static const bool value = _IsNotSame<__swap1, __nat>::value
3250                           && _IsNotSame<__swap2, __nat>::value;
3251};
3252
3253template <class _Tp, class _Up>
3254struct __swappable_with<_Tp, _Up,  false> : false_type {};
3255
3256template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
3257struct __nothrow_swappable_with {
3258  static const bool value =
3259#ifndef _LIBCPP_HAS_NO_NOEXCEPT
3260      noexcept(swap(declval<_Tp>(), declval<_Up>()))
3261  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
3262#else
3263      false;
3264#endif
3265};
3266
3267template <class _Tp, class _Up>
3268struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
3269
3270} // namespace __detail
3271
3272template <class _Tp>
3273struct __is_swappable
3274    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
3275{
3276};
3277
3278template <class _Tp>
3279struct __is_nothrow_swappable
3280    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
3281{
3282};
3283
3284#if _LIBCPP_STD_VER > 14
3285
3286template <class _Tp, class _Up>
3287struct _LIBCPP_TEMPLATE_VIS is_swappable_with
3288    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
3289{
3290};
3291
3292template <class _Tp>
3293struct _LIBCPP_TEMPLATE_VIS is_swappable
3294    : public conditional<
3295        __is_referenceable<_Tp>::value,
3296        is_swappable_with<
3297            typename add_lvalue_reference<_Tp>::type,
3298            typename add_lvalue_reference<_Tp>::type>,
3299        false_type
3300    >::type
3301{
3302};
3303
3304template <class _Tp, class _Up>
3305struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
3306    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
3307{
3308};
3309
3310template <class _Tp>
3311struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
3312    : public conditional<
3313        __is_referenceable<_Tp>::value,
3314        is_nothrow_swappable_with<
3315            typename add_lvalue_reference<_Tp>::type,
3316            typename add_lvalue_reference<_Tp>::type>,
3317        false_type
3318    >::type
3319{
3320};
3321
3322template <class _Tp, class _Up>
3323inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
3324
3325template <class _Tp>
3326inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;
3327
3328template <class _Tp, class _Up>
3329inline constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
3330
3331template <class _Tp>
3332inline constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
3333
3334#endif // _LIBCPP_STD_VER > 14
3335
3336template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
3337
3338template <class _Tp>
3339struct __underlying_type_impl<_Tp, false> {};
3340
3341template <class _Tp>
3342struct __underlying_type_impl<_Tp, true>
3343{
3344    typedef __underlying_type(_Tp) type;
3345};
3346
3347template <class _Tp>
3348struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
3349
3350#if _LIBCPP_STD_VER > 11
3351template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
3352#endif
3353
3354template <class _Tp, bool = is_enum<_Tp>::value>
3355struct __sfinae_underlying_type
3356{
3357    typedef typename underlying_type<_Tp>::type type;
3358    typedef decltype(((type)1) + 0) __promoted_type;
3359};
3360
3361template <class _Tp>
3362struct __sfinae_underlying_type<_Tp, false> {};
3363
3364inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3365int __convert_to_integral(int __val) { return __val; }
3366
3367inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3368unsigned __convert_to_integral(unsigned __val) { return __val; }
3369
3370inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3371long __convert_to_integral(long __val) { return __val; }
3372
3373inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3374unsigned long __convert_to_integral(unsigned long __val) { return __val; }
3375
3376inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3377long long __convert_to_integral(long long __val) { return __val; }
3378
3379inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3380unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
3381
3382template<typename _Fp>
3383inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3384typename enable_if<is_floating_point<_Fp>::value, long long>::type
3385 __convert_to_integral(_Fp __val) { return __val; }
3386
3387#ifndef _LIBCPP_HAS_NO_INT128
3388inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3389__int128_t __convert_to_integral(__int128_t __val) { return __val; }
3390
3391inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3392__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
3393#endif
3394
3395template <class _Tp>
3396inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
3397typename __sfinae_underlying_type<_Tp>::__promoted_type
3398__convert_to_integral(_Tp __val) { return __val; }
3399
3400// is_scoped_enum [meta.unary.prop]
3401
3402#if _LIBCPP_STD_VER > 20
3403template <class _Tp, bool = is_enum_v<_Tp> >
3404struct __is_scoped_enum_helper : false_type {};
3405
3406template <class _Tp>
3407struct __is_scoped_enum_helper<_Tp, true>
3408    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
3409
3410template <class _Tp>
3411struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
3412    : public __is_scoped_enum_helper<_Tp> {};
3413
3414template <class _Tp>
3415inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
3416#endif
3417
3418#if _LIBCPP_STD_VER > 14
3419
3420template <class... _Args>
3421struct conjunction : _And<_Args...> {};
3422template<class... _Args>
3423inline constexpr bool conjunction_v = conjunction<_Args...>::value;
3424
3425template <class... _Args>
3426struct disjunction : _Or<_Args...> {};
3427template<class... _Args>
3428inline constexpr bool disjunction_v = disjunction<_Args...>::value;
3429
3430template <class _Tp>
3431struct negation : _Not<_Tp> {};
3432template<class _Tp>
3433inline constexpr bool negation_v = negation<_Tp>::value;
3434#endif // _LIBCPP_STD_VER > 14
3435
3436// These traits are used in __tree and __hash_table
3437struct __extract_key_fail_tag {};
3438struct __extract_key_self_tag {};
3439struct __extract_key_first_tag {};
3440
3441template <class _ValTy, class _Key,
3442          class _RawValTy = typename __unconstref<_ValTy>::type>
3443struct __can_extract_key
3444    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
3445                  __extract_key_fail_tag>::type {};
3446
3447template <class _Pair, class _Key, class _First, class _Second>
3448struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
3449    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
3450                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
3451
3452// __can_extract_map_key uses true_type/false_type instead of the tags.
3453// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
3454// and _ValTy == _Key.
3455template <class _ValTy, class _Key, class _ContainerValueTy,
3456          class _RawValTy = typename __unconstref<_ValTy>::type>
3457struct __can_extract_map_key
3458    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
3459
3460// This specialization returns __extract_key_fail_tag for non-map containers
3461// because _Key == _ContainerValueTy
3462template <class _ValTy, class _Key, class _RawValTy>
3463struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
3464    : false_type {};
3465
3466#if _LIBCPP_STD_VER > 17
3467_LIBCPP_INLINE_VISIBILITY
3468inline constexpr bool is_constant_evaluated() noexcept {
3469  return __builtin_is_constant_evaluated();
3470}
3471#endif
3472
3473inline _LIBCPP_CONSTEXPR
3474bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
3475
3476template <class _CharT>
3477using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
3478
3479template<class _Tp>
3480using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
3481
3482#if _LIBCPP_STD_VER > 17
3483template<bool _Const, class _Tp>
3484using __maybe_const = conditional_t<_Const, const _Tp, _Tp>;
3485#endif // _LIBCPP_STD_VER > 17
3486
3487_LIBCPP_END_NAMESPACE_STD
3488
3489#endif // _LIBCPP_TYPE_TRAITS
3490