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