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