1// -*- C++ -*-
2//===------------------------ type_traits ---------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_TYPE_TRAITS
11#define _LIBCPP_TYPE_TRAITS
12
13/*
14    type_traits synopsis
15
16namespace std
17{
18
19    // helper class:
20    template <class T, T v> struct integral_constant;
21    typedef integral_constant<bool, true>  true_type;   // C++11
22    typedef integral_constant<bool, false> false_type;  // C++11
23
24    template <bool B>                                   // C++14
25    using bool_constant = integral_constant<bool, B>;   // C++14
26    typedef bool_constant<true> true_type;              // C++14
27    typedef bool_constant<false> false_type;            // C++14
28
29    // helper traits
30    template <bool, class T = void> struct enable_if;
31    template <bool, class T, class F> struct conditional;
32
33    // Primary classification traits:
34    template <class T> struct is_void;
35    template <class T> struct is_null_pointer;  // C++14
36    template <class T> struct is_integral;
37    template <class T> struct is_floating_point;
38    template <class T> struct is_array;
39    template <class T> struct is_pointer;
40    template <class T> struct is_lvalue_reference;
41    template <class T> struct is_rvalue_reference;
42    template <class T> struct is_member_object_pointer;
43    template <class T> struct is_member_function_pointer;
44    template <class T> struct is_enum;
45    template <class T> struct is_union;
46    template <class T> struct is_class;
47    template <class T> struct is_function;
48
49    // Secondary classification traits:
50    template <class T> struct is_reference;
51    template <class T> struct is_arithmetic;
52    template <class T> struct is_fundamental;
53    template <class T> struct is_member_pointer;
54    template <class T> struct is_scalar;
55    template <class T> struct is_object;
56    template <class T> struct is_compound;
57
58    // Const-volatile properties and transformations:
59    template <class T> struct is_const;
60    template <class T> struct is_volatile;
61    template <class T> struct remove_const;
62    template <class T> struct remove_volatile;
63    template <class T> struct remove_cv;
64    template <class T> struct add_const;
65    template <class T> struct add_volatile;
66    template <class T> struct add_cv;
67
68    // Reference transformations:
69    template <class T> struct remove_reference;
70    template <class T> struct add_lvalue_reference;
71    template <class T> struct add_rvalue_reference;
72
73    // Pointer transformations:
74    template <class T> struct remove_pointer;
75    template <class T> struct add_pointer;
76
77    template<class T> struct type_identity;                     // C++20
78    template<class T>
79      using type_identity_t = typename type_identity<T>::type;  // C++20
80
81    // Integral properties:
82    template <class T> struct is_signed;
83    template <class T> struct is_unsigned;
84    template <class T> struct make_signed;
85    template <class T> struct make_unsigned;
86
87    // Array properties and transformations:
88    template <class T> struct rank;
89    template <class T, unsigned I = 0> struct extent;
90    template <class T> struct remove_extent;
91    template <class T> struct remove_all_extents;
92
93    template <class T> struct is_bounded_array;                 // C++20
94    template <class T> struct is_unbounded_array;               // C++20
95
96    // Member introspection:
97    template <class T> struct is_pod;
98    template <class T> struct is_trivial;
99    template <class T> struct is_trivially_copyable;
100    template <class T> struct is_standard_layout;
101    template <class T> struct is_literal_type;
102    template <class T> struct is_empty;
103    template <class T> struct is_polymorphic;
104    template <class T> struct is_abstract;
105    template <class T> struct is_final; // C++14
106    template <class T> struct is_aggregate; // C++17
107
108    template <class T, class... Args> struct is_constructible;
109    template <class T>                struct is_default_constructible;
110    template <class T>                struct is_copy_constructible;
111    template <class T>                struct is_move_constructible;
112    template <class T, class U>       struct is_assignable;
113    template <class T>                struct is_copy_assignable;
114    template <class T>                struct is_move_assignable;
115    template <class T, class U>       struct is_swappable_with;       // C++17
116    template <class T>                struct is_swappable;            // C++17
117    template <class T>                struct is_destructible;
118
119    template <class T, class... Args> struct is_trivially_constructible;
120    template <class T>                struct is_trivially_default_constructible;
121    template <class T>                struct is_trivially_copy_constructible;
122    template <class T>                struct is_trivially_move_constructible;
123    template <class T, class U>       struct is_trivially_assignable;
124    template <class T>                struct is_trivially_copy_assignable;
125    template <class T>                struct is_trivially_move_assignable;
126    template <class T>                struct is_trivially_destructible;
127
128    template <class T, class... Args> struct is_nothrow_constructible;
129    template <class T>                struct is_nothrow_default_constructible;
130    template <class T>                struct is_nothrow_copy_constructible;
131    template <class T>                struct is_nothrow_move_constructible;
132    template <class T, class U>       struct is_nothrow_assignable;
133    template <class T>                struct is_nothrow_copy_assignable;
134    template <class T>                struct is_nothrow_move_assignable;
135    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
136    template <class T>                struct is_nothrow_swappable;      // C++17
137    template <class T>                struct is_nothrow_destructible;
138
139    template <class T> struct has_virtual_destructor;
140
141    template<class T> struct has_unique_object_representations;         // C++17
142
143    // Relationships between types:
144    template <class T, class U> struct is_same;
145    template <class Base, class Derived> struct is_base_of;
146
147    template <class From, class To> struct is_convertible;
148    template <typename From, typename To> struct is_nothrow_convertible;                  // C++20
149    template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
150
151    template <class Fn, class... ArgTypes> struct is_invocable;
152    template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
153
154    template <class Fn, class... ArgTypes> struct is_nothrow_invocable;
155    template <class R, class Fn, class... ArgTypes> struct is_nothrow_invocable_r;
156
157    // Alignment properties and transformations:
158    template <class T> struct alignment_of;
159    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
160        struct aligned_storage;
161    template <size_t Len, class... Types> struct aligned_union;
162    template <class T> struct remove_cvref; // C++20
163
164    template <class T> struct decay;
165    template <class... T> struct common_type;
166    template <class T> struct underlying_type;
167    template <class> class result_of; // undefined
168    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>;
169    template <class Fn, class... ArgTypes> struct invoke_result;  // C++17
170
171    // const-volatile modifications:
172    template <class T>
173      using remove_const_t    = typename remove_const<T>::type;  // C++14
174    template <class T>
175      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
176    template <class T>
177      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
178    template <class T>
179      using add_const_t       = typename add_const<T>::type;  // C++14
180    template <class T>
181      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
182    template <class T>
183      using add_cv_t          = typename add_cv<T>::type;  // C++14
184
185    // reference modifications:
186    template <class T>
187      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
188    template <class T>
189      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
190    template <class T>
191      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
192
193    // sign modifications:
194    template <class T>
195      using make_signed_t   = typename make_signed<T>::type;  // C++14
196    template <class T>
197      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
198
199    // array modifications:
200    template <class T>
201      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
202    template <class T>
203      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
204
205    template <class T>
206      inline constexpr bool is_bounded_array_v
207        = is_bounded_array<T>::value;                                     // C++20
208      inline constexpr bool is_unbounded_array_v
209        = is_unbounded_array<T>::value;                                   // C++20
210
211    // pointer modifications:
212    template <class T>
213      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
214    template <class T>
215      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
216
217    // other transformations:
218    template <size_t Len, std::size_t Align=default-alignment>
219      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
220    template <std::size_t Len, class... Types>
221      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
222    template <class T>
223      using remove_cvref_t    = typename remove_cvref<T>::type;  // C++20
224    template <class T>
225      using decay_t           = typename decay<T>::type;  // C++14
226    template <bool b, class T=void>
227      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
228    template <bool b, class T, class F>
229      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
230    template <class... T>
231      using common_type_t     = typename common_type<T...>::type;  // C++14
232    template <class T>
233      using underlying_type_t = typename underlying_type<T>::type;  // C++14
234    template <class T>
235      using result_of_t       = typename result_of<T>::type;  // C++14
236    template <class Fn, class... ArgTypes>
237      using invoke_result_t   = typename invoke_result<Fn, ArgTypes...>::type;  // C++17
238
239    template <class...>
240      using void_t = void;   // C++17
241
242      // See C++14 20.10.4.1, primary type categories
243      template <class T> inline constexpr bool is_void_v
244        = is_void<T>::value;                                             // C++17
245      template <class T> inline constexpr bool is_null_pointer_v
246        = is_null_pointer<T>::value;                                     // C++17
247      template <class T> inline constexpr bool is_integral_v
248        = is_integral<T>::value;                                         // C++17
249      template <class T> inline constexpr bool is_floating_point_v
250        = is_floating_point<T>::value;                                   // C++17
251      template <class T> inline constexpr bool is_array_v
252        = is_array<T>::value;                                            // C++17
253      template <class T> inline constexpr bool is_pointer_v
254        = is_pointer<T>::value;                                          // C++17
255      template <class T> inline constexpr bool is_lvalue_reference_v
256        = is_lvalue_reference<T>::value;                                 // C++17
257      template <class T> inline constexpr bool is_rvalue_reference_v
258        = is_rvalue_reference<T>::value;                                 // C++17
259      template <class T> inline constexpr bool is_member_object_pointer_v
260        = is_member_object_pointer<T>::value;                            // C++17
261      template <class T> inline constexpr bool is_member_function_pointer_v
262        = is_member_function_pointer<T>::value;                          // C++17
263      template <class T> inline constexpr bool is_enum_v
264        = is_enum<T>::value;                                             // C++17
265      template <class T> inline constexpr bool is_union_v
266        = is_union<T>::value;                                            // C++17
267      template <class T> inline constexpr bool is_class_v
268        = is_class<T>::value;                                            // C++17
269      template <class T> inline constexpr bool is_function_v
270        = is_function<T>::value;                                         // C++17
271
272      // See C++14 20.10.4.2, composite type categories
273      template <class T> inline constexpr bool is_reference_v
274        = is_reference<T>::value;                                        // C++17
275      template <class T> inline constexpr bool is_arithmetic_v
276        = is_arithmetic<T>::value;                                       // C++17
277      template <class T> inline constexpr bool is_fundamental_v
278        = is_fundamental<T>::value;                                      // C++17
279      template <class T> inline constexpr bool is_object_v
280        = is_object<T>::value;                                           // C++17
281      template <class T> inline constexpr bool is_scalar_v
282        = is_scalar<T>::value;                                           // C++17
283      template <class T> inline constexpr bool is_compound_v
284        = is_compound<T>::value;                                         // C++17
285      template <class T> inline constexpr bool is_member_pointer_v
286        = is_member_pointer<T>::value;                                   // C++17
287
288      // See C++14 20.10.4.3, type properties
289      template <class T> inline constexpr bool is_const_v
290        = is_const<T>::value;                                            // C++17
291      template <class T> inline constexpr bool is_volatile_v
292        = is_volatile<T>::value;                                         // C++17
293      template <class T> inline constexpr bool is_trivial_v
294        = is_trivial<T>::value;                                          // C++17
295      template <class T> inline constexpr bool is_trivially_copyable_v
296        = is_trivially_copyable<T>::value;                               // C++17
297      template <class T> inline constexpr bool is_standard_layout_v
298        = is_standard_layout<T>::value;                                  // C++17
299      template <class T> inline constexpr bool is_pod_v
300        = is_pod<T>::value;                                              // C++17
301      template <class T> inline constexpr bool is_literal_type_v
302        = is_literal_type<T>::value;                                     // C++17
303      template <class T> inline constexpr bool is_empty_v
304        = is_empty<T>::value;                                            // C++17
305      template <class T> inline constexpr bool is_polymorphic_v
306        = is_polymorphic<T>::value;                                      // C++17
307      template <class T> inline constexpr bool is_abstract_v
308        = is_abstract<T>::value;                                         // C++17
309      template <class T> inline constexpr bool is_final_v
310        = is_final<T>::value;                                            // C++17
311      template <class T> inline constexpr bool is_aggregate_v
312        = is_aggregate<T>::value;                                        // C++17
313      template <class T> inline constexpr bool is_signed_v
314        = is_signed<T>::value;                                           // C++17
315      template <class T> inline constexpr bool is_unsigned_v
316        = is_unsigned<T>::value;                                         // C++17
317      template <class T, class... Args> inline constexpr bool is_constructible_v
318        = is_constructible<T, Args...>::value;                           // C++17
319      template <class T> inline constexpr bool is_default_constructible_v
320        = is_default_constructible<T>::value;                            // C++17
321      template <class T> inline constexpr bool is_copy_constructible_v
322        = is_copy_constructible<T>::value;                               // C++17
323      template <class T> inline constexpr bool is_move_constructible_v
324        = is_move_constructible<T>::value;                               // C++17
325      template <class T, class U> inline constexpr bool is_assignable_v
326        = is_assignable<T, U>::value;                                    // C++17
327      template <class T> inline constexpr bool is_copy_assignable_v
328        = is_copy_assignable<T>::value;                                  // C++17
329      template <class T> inline constexpr bool is_move_assignable_v
330        = is_move_assignable<T>::value;                                  // C++17
331      template <class T, class U> inline constexpr bool is_swappable_with_v
332        = is_swappable_with<T, U>::value;                                // C++17
333      template <class T> inline constexpr bool is_swappable_v
334        = is_swappable<T>::value;                                        // C++17
335      template <class T> inline constexpr bool is_destructible_v
336        = is_destructible<T>::value;                                     // C++17
337      template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
338        = is_trivially_constructible<T, Args...>::value;                 // C++17
339      template <class T> inline constexpr bool is_trivially_default_constructible_v
340        = is_trivially_default_constructible<T>::value;                  // C++17
341      template <class T> inline constexpr bool is_trivially_copy_constructible_v
342        = is_trivially_copy_constructible<T>::value;                     // C++17
343      template <class T> inline constexpr bool is_trivially_move_constructible_v
344        = is_trivially_move_constructible<T>::value;                     // C++17
345      template <class T, class U> inline constexpr bool is_trivially_assignable_v
346        = is_trivially_assignable<T, U>::value;                          // C++17
347      template <class T> inline constexpr bool is_trivially_copy_assignable_v
348        = is_trivially_copy_assignable<T>::value;                        // C++17
349      template <class T> inline constexpr bool is_trivially_move_assignable_v
350        = is_trivially_move_assignable<T>::value;                        // C++17
351      template <class T> inline constexpr bool is_trivially_destructible_v
352        = is_trivially_destructible<T>::value;                           // C++17
353      template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
354        = is_nothrow_constructible<T, Args...>::value;                   // C++17
355      template <class T> inline constexpr bool is_nothrow_default_constructible_v
356        = is_nothrow_default_constructible<T>::value;                    // C++17
357      template <class T> inline constexpr bool is_nothrow_copy_constructible_v
358        = is_nothrow_copy_constructible<T>::value;                       // C++17
359      template <class T> inline constexpr bool is_nothrow_move_constructible_v
360        = is_nothrow_move_constructible<T>::value;                       // C++17
361      template <class T, class U> inline constexpr bool is_nothrow_assignable_v
362        = is_nothrow_assignable<T, U>::value;                            // C++17
363      template <class T> inline constexpr bool is_nothrow_copy_assignable_v
364        = is_nothrow_copy_assignable<T>::value;                          // C++17
365      template <class T> inline constexpr bool is_nothrow_move_assignable_v
366        = is_nothrow_move_assignable<T>::value;                          // C++17
367      template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
368        = is_nothrow_swappable_with<T, U>::value;                       // C++17
369      template <class T> inline constexpr bool is_nothrow_swappable_v
370        = is_nothrow_swappable<T>::value;                               // C++17
371      template <class T> inline constexpr bool is_nothrow_destructible_v
372        = is_nothrow_destructible<T>::value;                             // C++17
373      template <class T> inline constexpr bool has_virtual_destructor_v
374        = has_virtual_destructor<T>::value;                              // C++17
375      template<class T> inline constexpr bool has_unique_object_representations_v // C++17
376        = has_unique_object_representations<T>::value;
377
378      // See C++14 20.10.5, type property queries
379      template <class T> inline constexpr size_t alignment_of_v
380        = alignment_of<T>::value;                                        // C++17
381      template <class T> inline constexpr size_t rank_v
382        = rank<T>::value;                                                // C++17
383      template <class T, unsigned I = 0> inline constexpr size_t extent_v
384        = extent<T, I>::value;                                           // C++17
385
386      // See C++14 20.10.6, type relations
387      template <class T, class U> inline constexpr bool is_same_v
388        = is_same<T, U>::value;                                          // C++17
389      template <class Base, class Derived> inline constexpr bool is_base_of_v
390        = is_base_of<Base, Derived>::value;                              // C++17
391      template <class From, class To> inline constexpr bool is_convertible_v
392        = is_convertible<From, To>::value;                               // C++17
393      template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
394        = is_invocable<Fn, ArgTypes...>::value;                          // C++17
395      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
396        = is_invocable_r<R, Fn, ArgTypes...>::value;                     // C++17
397      template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
398        = is_nothrow_invocable<Fn, ArgTypes...>::value;                  // C++17
399      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
400        = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value;             // C++17
401
402      // [meta.logical], logical operator traits:
403      template<class... B> struct conjunction;                           // C++17
404      template<class... B>
405        inline constexpr bool conjunction_v = conjunction<B...>::value;  // C++17
406      template<class... B> struct disjunction;                           // C++17
407      template<class... B>
408        inline constexpr bool disjunction_v = disjunction<B...>::value;  // C++17
409      template<class B> struct negation;                                 // C++17
410      template<class B>
411        inline constexpr bool negation_v = negation<B>::value;           // C++17
412
413}
414
415*/
416#include <__config>
417#include <cstddef>
418#include <version>
419
420#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
421#pragma GCC system_header
422#endif
423
424_LIBCPP_BEGIN_NAMESPACE_STD
425
426template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
427template <class _Tp> class _LIBCPP_TEMPLATE_VIS reference_wrapper;
428template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
429
430template <class _Tp, _Tp __v>
431struct _LIBCPP_TEMPLATE_VIS integral_constant
432{
433  static _LIBCPP_CONSTEXPR const _Tp      value = __v;
434  typedef _Tp               value_type;
435  typedef integral_constant type;
436  _LIBCPP_INLINE_VISIBILITY
437  _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
438#if _LIBCPP_STD_VER > 11
439  _LIBCPP_INLINE_VISIBILITY
440  constexpr value_type operator ()() const _NOEXCEPT {return value;}
441#endif
442};
443
444template <class _Tp, _Tp __v>
445_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
446
447#if _LIBCPP_STD_VER > 14
448template <bool __b>
449using bool_constant = integral_constant<bool, __b>;
450#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
451#else
452#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
453#endif
454
455typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
456typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
457
458template <bool _Val>
459using _BoolConstant _LIBCPP_NODEBUG_TYPE = integral_constant<bool, _Val>;
460
461template <bool> struct _MetaBase;
462template <>
463struct _MetaBase<true> {
464  template <class _Tp, class _Up>
465  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Tp;
466  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
467  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _FirstFn<_Args...>;
468  template <class _First, class...>
469  using _FirstImpl _LIBCPP_NODEBUG_TYPE = _First;
470  template <class, class _Second, class...>
471  using _SecondImpl _LIBCPP_NODEBUG_TYPE = _Second;
472  template <class _Tp = void>
473  using _EnableIfImpl _LIBCPP_NODEBUG_TYPE = _Tp;
474  template <class _Result, class _First, class ..._Rest>
475  using _OrImpl _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
476  template <class _Result, class _First, class ..._Rest>
477  using _AndImpl _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_First::value == true && sizeof...(_Rest) != 0>::template _AndImpl<_First, _Rest...>;
478};
479
480template <>
481struct _MetaBase<false> {
482  template <class _Tp, class _Up>
483  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Up;
484  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
485  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _SecondFn<_Args...>;
486  template <class _Result, class ...>
487  using _OrImpl _LIBCPP_NODEBUG_TYPE = _Result;
488  template <class _Result, class ...>
489  using _AndImpl _LIBCPP_NODEBUG_TYPE = _Result;
490};
491template <bool _Cond, class _Ret = void>
492using _EnableIf _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _EnableIfImpl<_Ret>;
493template <bool _Cond, class _IfRes, class _ElseRes>
494using _If _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
495template <class ..._Rest>
496using _Or _LIBCPP_NODEBUG_TYPE = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
497template <class ..._Rest>
498using _And _LIBCPP_NODEBUG_TYPE = typename _MetaBase< sizeof...(_Rest) != 0 >::template _AndImpl<true_type, _Rest...>;
499template <class _Pred>
500struct _Not : _BoolConstant<!_Pred::value> {};
501template <class ..._Args>
502using _FirstType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
503template <class ..._Args>
504using _SecondType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
505
506template <template <class...> class _Func, class ..._Args>
507struct _Lazy : _Func<_Args...> {};
508
509// Member detector base
510
511template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
512true_type __sfinae_test_impl(int);
513template <template <class...> class, class ...>
514false_type __sfinae_test_impl(...);
515
516template <template <class ...> class _Templ, class ..._Args>
517using _IsValidExpansion _LIBCPP_NODEBUG_TYPE = decltype(std::__sfinae_test_impl<_Templ, _Args...>(0));
518
519template <class>
520struct __void_t { typedef void type; };
521
522template <class _Tp>
523struct __identity { typedef _Tp type; };
524
525template <class _Tp, bool>
526struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
527
528
529template <bool _Bp, class _If, class _Then>
530    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
531template <class _If, class _Then>
532    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
533
534#if _LIBCPP_STD_VER > 11
535template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
536#endif
537
538template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
539template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
540
541#if _LIBCPP_STD_VER > 11
542template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
543#endif
544
545// is_same
546
547#if __has_keyword(__is_same)
548
549template <class _Tp, class _Up>
550struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
551
552#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
553template <class _Tp, class _Up>
554_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v = __is_same(_Tp, _Up);
555#endif
556
557#else
558
559template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
560template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
561
562#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
563template <class _Tp, class _Up>
564_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v
565    = is_same<_Tp, _Up>::value;
566#endif
567
568#endif // __is_same
569
570template <class _Tp, class _Up>
571using _IsSame = _BoolConstant<
572#ifdef __clang__
573    __is_same(_Tp, _Up)
574#else
575    _VSTD::is_same<_Tp, _Up>::value
576#endif
577>;
578
579template <class _Tp, class _Up>
580using _IsNotSame = _BoolConstant<
581#ifdef __clang__
582    !__is_same(_Tp, _Up)
583#else
584    !_VSTD::is_same<_Tp, _Up>::value
585#endif
586>;
587
588
589template <class _Tp>
590using __test_for_primary_template = _EnableIf<
591    _IsSame<_Tp, typename _Tp::__primary_template>::value
592  >;
593template <class _Tp>
594using __is_primary_template = _IsValidExpansion<
595    __test_for_primary_template, _Tp
596  >;
597
598// addressof
599#ifndef _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
600
601template <class _Tp>
602inline _LIBCPP_CONSTEXPR_AFTER_CXX14
603_LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
604_Tp*
605addressof(_Tp& __x) _NOEXCEPT
606{
607    return __builtin_addressof(__x);
608}
609
610#else
611
612template <class _Tp>
613inline _LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
614_Tp*
615addressof(_Tp& __x) _NOEXCEPT
616{
617  return reinterpret_cast<_Tp *>(
618      const_cast<char *>(&reinterpret_cast<const volatile char &>(__x)));
619}
620
621#endif // _LIBCPP_HAS_NO_BUILTIN_ADDRESSOF
622
623#if defined(_LIBCPP_HAS_OBJC_ARC) && !defined(_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF)
624// Objective-C++ Automatic Reference Counting uses qualified pointers
625// that require special addressof() signatures. When
626// _LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF is defined, the compiler
627// itself is providing these definitions. Otherwise, we provide them.
628template <class _Tp>
629inline _LIBCPP_INLINE_VISIBILITY
630__strong _Tp*
631addressof(__strong _Tp& __x) _NOEXCEPT
632{
633  return &__x;
634}
635
636#ifdef _LIBCPP_HAS_OBJC_ARC_WEAK
637template <class _Tp>
638inline _LIBCPP_INLINE_VISIBILITY
639__weak _Tp*
640addressof(__weak _Tp& __x) _NOEXCEPT
641{
642  return &__x;
643}
644#endif
645
646template <class _Tp>
647inline _LIBCPP_INLINE_VISIBILITY
648__autoreleasing _Tp*
649addressof(__autoreleasing _Tp& __x) _NOEXCEPT
650{
651  return &__x;
652}
653
654template <class _Tp>
655inline _LIBCPP_INLINE_VISIBILITY
656__unsafe_unretained _Tp*
657addressof(__unsafe_unretained _Tp& __x) _NOEXCEPT
658{
659  return &__x;
660}
661#endif
662
663#if !defined(_LIBCPP_CXX03_LANG)
664template <class _Tp> _Tp* addressof(const _Tp&&) noexcept = delete;
665#endif
666
667struct __two {char __lx[2];};
668
669// helper class:
670
671// is_const
672
673#if __has_keyword(__is_const)
674
675template <class _Tp>
676struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
677
678#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
679template <class _Tp>
680_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v = __is_const(_Tp);
681#endif
682
683#else
684
685template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
686template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
687
688#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
689template <class _Tp>
690_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v
691    = is_const<_Tp>::value;
692#endif
693
694#endif // __has_keyword(__is_const)
695
696// is_volatile
697
698#if __has_keyword(__is_volatile)
699
700template <class _Tp>
701struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
702
703#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
704template <class _Tp>
705_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v = __is_volatile(_Tp);
706#endif
707
708#else
709
710template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
711template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
712
713#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
714template <class _Tp>
715_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v
716    = is_volatile<_Tp>::value;
717#endif
718
719#endif // __has_keyword(__is_volatile)
720
721// remove_const
722
723#if __has_keyword(__remove_const)
724
725template <class _Tp>
726struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
727
728#if _LIBCPP_STD_VER > 11
729template <class _Tp> using remove_const_t = __remove_const(_Tp);
730#endif
731
732#else
733
734template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
735template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
736#if _LIBCPP_STD_VER > 11
737template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
738#endif
739
740#endif // __has_keyword(__remove_const)
741
742// remove_volatile
743
744#if __has_keyword(__remove_volatile)
745
746template <class _Tp>
747struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
748
749#if _LIBCPP_STD_VER > 11
750template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
751#endif
752
753#else
754
755template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
756template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
757#if _LIBCPP_STD_VER > 11
758template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
759#endif
760
761#endif // __has_keyword(__remove_volatile)
762
763// remove_cv
764
765#if __has_keyword(__remove_cv)
766
767template <class _Tp>
768struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
769
770#if _LIBCPP_STD_VER > 11
771template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
772#endif
773
774#else
775
776template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
777{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
778#if _LIBCPP_STD_VER > 11
779template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
780#endif
781
782#endif // __has_keyword(__remove_cv)
783
784// is_void
785
786#if __has_keyword(__is_void)
787
788template <class _Tp>
789struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
790
791#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
792template <class _Tp>
793_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v = __is_void(_Tp);
794#endif
795
796#else
797
798template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
799    : public is_same<typename remove_cv<_Tp>::type, void> {};
800
801#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
802template <class _Tp>
803_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v
804    = is_void<_Tp>::value;
805#endif
806
807#endif // __has_keyword(__is_void)
808
809// __is_nullptr_t
810
811template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
812template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
813
814template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
815    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
816
817#if _LIBCPP_STD_VER > 11
818template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
819    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
820
821#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
822template <class _Tp>
823_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_null_pointer_v
824    = is_null_pointer<_Tp>::value;
825#endif
826#endif // _LIBCPP_STD_VER > 11
827
828// is_integral
829
830#if __has_keyword(__is_integral)
831
832template <class _Tp>
833struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
834
835#if _LIBCPP_STD_VER > 14
836template <class _Tp>
837_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v = __is_integral(_Tp);
838#endif
839
840#else
841
842template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
843    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
844
845#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
846template <class _Tp>
847_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v
848    = is_integral<_Tp>::value;
849#endif
850
851#endif // __has_keyword(__is_integral)
852
853// is_floating_point
854
855template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
856template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
857template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
858template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
859
860template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
861    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
862
863#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
864template <class _Tp>
865_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_floating_point_v
866    = is_floating_point<_Tp>::value;
867#endif
868
869// is_array
870
871#if __has_keyword(__is_array)
872
873template <class _Tp>
874struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
875
876#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
877template <class _Tp>
878_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v = __is_array(_Tp);
879#endif
880
881#else
882
883template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
884    : public false_type {};
885template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
886    : public true_type {};
887template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
888    : public true_type {};
889
890#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
891template <class _Tp>
892_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v
893    = is_array<_Tp>::value;
894#endif
895
896#endif // __has_keyword(__is_array)
897
898// is_pointer
899
900// In clang 10.0.0 and earlier __is_pointer didn't work with Objective-C types.
901#if __has_keyword(__is_pointer) && _LIBCPP_CLANG_VER > 1000
902
903template<class _Tp>
904struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
905
906#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
907template <class _Tp>
908_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v = __is_pointer(_Tp);
909#endif
910
911#else // __has_keyword(__is_pointer)
912
913template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
914template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
915
916template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
917#if defined(_LIBCPP_HAS_OBJC_ARC)
918template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
919template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
920template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
921template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
922#endif
923
924template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
925    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
926
927#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
928template <class _Tp>
929_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v
930    = is_pointer<_Tp>::value;
931#endif
932
933#endif // __has_keyword(__is_pointer)
934
935// is_reference
936
937#if __has_keyword(__is_lvalue_reference) && \
938    __has_keyword(__is_rvalue_reference) && \
939    __has_keyword(__is_reference)
940
941template<class _Tp>
942struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
943
944template<class _Tp>
945struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
946
947template<class _Tp>
948struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
949
950#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
951template <class _Tp>
952_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v = __is_reference(_Tp);
953
954template <class _Tp>
955_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
956
957template <class _Tp>
958_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
959#endif
960
961#else // __has_keyword(__is_lvalue_reference) && etc...
962
963template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
964template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
965
966template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
967template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
968
969template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
970template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
971template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
972
973#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
974template <class _Tp>
975_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v
976    = is_reference<_Tp>::value;
977
978template <class _Tp>
979_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v
980    = is_lvalue_reference<_Tp>::value;
981
982template <class _Tp>
983_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v
984    = is_rvalue_reference<_Tp>::value;
985#endif
986
987#endif // __has_keyword(__is_lvalue_reference) && etc...
988
989// is_union
990
991#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
992
993template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
994    : public integral_constant<bool, __is_union(_Tp)> {};
995
996#else
997
998template <class _Tp> struct __libcpp_union : public false_type {};
999template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
1000    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
1001
1002#endif
1003
1004#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1005template <class _Tp>
1006_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_union_v
1007    = is_union<_Tp>::value;
1008#endif
1009
1010// is_class
1011
1012#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
1013
1014template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
1015    : public integral_constant<bool, __is_class(_Tp)> {};
1016
1017#else
1018
1019namespace __is_class_imp
1020{
1021template <class _Tp> char  __test(int _Tp::*);
1022template <class _Tp> __two __test(...);
1023}
1024
1025template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
1026    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
1027
1028#endif
1029
1030#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1031template <class _Tp>
1032_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_class_v
1033    = is_class<_Tp>::value;
1034#endif
1035
1036// is_function
1037
1038template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
1039    : public _BoolConstant<
1040#ifdef __clang__
1041    __is_function(_Tp)
1042#else
1043 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
1044#endif
1045    > {};
1046
1047
1048#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1049template <class _Tp>
1050_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_function_v
1051    = is_function<_Tp>::value;
1052#endif
1053
1054template <class _Tp> struct __libcpp_is_member_pointer {
1055  enum {
1056    __is_member = false,
1057    __is_func = false,
1058    __is_obj = false
1059  };
1060};
1061template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
1062  enum {
1063    __is_member = true,
1064    __is_func = is_function<_Tp>::value,
1065    __is_obj = !__is_func,
1066  };
1067};
1068
1069#if __has_keyword(__is_member_function_pointer)
1070
1071template<class _Tp>
1072struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1073    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1074
1075#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1076template <class _Tp>
1077_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1078    = __is_member_function_pointer(_Tp);
1079#endif
1080
1081#else // __has_keyword(__is_member_function_pointer)
1082
1083template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1084    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1085
1086#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1087template <class _Tp>
1088_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1089    = is_member_function_pointer<_Tp>::value;
1090#endif
1091
1092#endif // __has_keyword(__is_member_function_pointer)
1093
1094// is_member_pointer
1095
1096#if __has_keyword(__is_member_pointer)
1097
1098template<class _Tp>
1099struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
1100
1101#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1102template <class _Tp>
1103_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v = __is_member_pointer(_Tp);
1104#endif
1105
1106#else // __has_keyword(__is_member_pointer)
1107
1108template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1109 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1110
1111#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1112template <class _Tp>
1113_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v
1114    = is_member_pointer<_Tp>::value;
1115#endif
1116
1117#endif // __has_keyword(__is_member_pointer)
1118
1119// is_member_object_pointer
1120
1121#if __has_keyword(__is_member_object_pointer)
1122
1123template<class _Tp>
1124struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1125    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1126
1127#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1128template <class _Tp>
1129_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1130    = __is_member_object_pointer(_Tp);
1131#endif
1132
1133#else // __has_keyword(__is_member_object_pointer)
1134
1135template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1136    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1137
1138#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1139template <class _Tp>
1140_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1141    = is_member_object_pointer<_Tp>::value;
1142#endif
1143
1144#endif // __has_keyword(__is_member_object_pointer)
1145
1146// is_enum
1147
1148#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1149
1150template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1151    : public integral_constant<bool, __is_enum(_Tp)> {};
1152
1153#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1154template <class _Tp>
1155_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v = __is_enum(_Tp);
1156#endif
1157
1158#else
1159
1160template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1161    : public integral_constant<bool, !is_void<_Tp>::value             &&
1162                                     !is_integral<_Tp>::value         &&
1163                                     !is_floating_point<_Tp>::value   &&
1164                                     !is_array<_Tp>::value            &&
1165                                     !is_pointer<_Tp>::value          &&
1166                                     !is_reference<_Tp>::value        &&
1167                                     !is_member_pointer<_Tp>::value   &&
1168                                     !is_union<_Tp>::value            &&
1169                                     !is_class<_Tp>::value            &&
1170                                     !is_function<_Tp>::value         > {};
1171
1172#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1173template <class _Tp>
1174_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v
1175    = is_enum<_Tp>::value;
1176#endif
1177
1178#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1179
1180// is_arithmetic
1181
1182
1183template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1184    : public integral_constant<bool, is_integral<_Tp>::value      ||
1185                                     is_floating_point<_Tp>::value> {};
1186
1187#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1188template <class _Tp>
1189_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_arithmetic_v
1190    = is_arithmetic<_Tp>::value;
1191#endif
1192
1193// is_fundamental
1194
1195// In clang 9 and lower, this builtin did not work for nullptr_t. Additionally, in C++03 mode,
1196// nullptr isn't defined by the compiler so, this builtin won't work.
1197#if __has_keyword(__is_fundamental) && _LIBCPP_CLANG_VER > 900 && !defined(_LIBCPP_CXX03_LANG)
1198
1199template<class _Tp>
1200struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1201
1202#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1203template <class _Tp>
1204_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v = __is_fundamental(_Tp);
1205#endif
1206
1207#else // __has_keyword(__is_fundamental)
1208
1209template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1210    : public integral_constant<bool, is_void<_Tp>::value        ||
1211                                     __is_nullptr_t<_Tp>::value ||
1212                                     is_arithmetic<_Tp>::value> {};
1213
1214#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1215template <class _Tp>
1216_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v
1217    = is_fundamental<_Tp>::value;
1218#endif
1219
1220#endif // __has_keyword(__is_fundamental)
1221
1222// is_scalar
1223
1224// >= 11 because in C++03 nullptr isn't actually nullptr
1225#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1226
1227template<class _Tp>
1228struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1229
1230#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1231template <class _Tp>
1232_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v = __is_scalar(_Tp);
1233#endif
1234
1235#else // __has_keyword(__is_scalar)
1236
1237template <class _Tp> struct __is_block : false_type {};
1238#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1239template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1240#endif
1241
1242template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1243    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1244                                     is_member_pointer<_Tp>::value ||
1245                                     is_pointer<_Tp>::value        ||
1246                                     __is_nullptr_t<_Tp>::value    ||
1247                                     __is_block<_Tp>::value        ||
1248                                     is_enum<_Tp>::value           > {};
1249
1250template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1251
1252#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1253template <class _Tp>
1254_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v
1255    = is_scalar<_Tp>::value;
1256#endif
1257
1258#endif // __has_keyword(__is_scalar)
1259
1260// is_object
1261
1262#if __has_keyword(__is_object)
1263
1264template<class _Tp>
1265struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1266
1267#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1268template <class _Tp>
1269_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v = __is_object(_Tp);
1270#endif
1271
1272#else // __has_keyword(__is_object)
1273
1274template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1275    : public integral_constant<bool, is_scalar<_Tp>::value ||
1276                                     is_array<_Tp>::value  ||
1277                                     is_union<_Tp>::value  ||
1278                                     is_class<_Tp>::value  > {};
1279
1280#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1281template <class _Tp>
1282_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v
1283    = is_object<_Tp>::value;
1284#endif
1285
1286#endif // __has_keyword(__is_object)
1287
1288// is_compound
1289
1290// >= 11 because in C++03 nullptr isn't actually nullptr
1291#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1292
1293template<class _Tp>
1294struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1295
1296#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1297template <class _Tp>
1298_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v = __is_compound(_Tp);
1299#endif
1300
1301#else // __has_keyword(__is_compound)
1302
1303template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1304    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1305
1306#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1307template <class _Tp>
1308_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v
1309    = is_compound<_Tp>::value;
1310#endif
1311
1312#endif // __has_keyword(__is_compound)
1313
1314// __is_referenceable  [defns.referenceable]
1315
1316struct __is_referenceable_impl {
1317    template <class _Tp> static _Tp& __test(int);
1318    template <class _Tp> static __two __test(...);
1319};
1320
1321template <class _Tp>
1322struct __is_referenceable : integral_constant<bool,
1323    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1324
1325
1326// add_const
1327
1328template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1329  typedef _LIBCPP_NODEBUG_TYPE const _Tp type;
1330};
1331
1332#if _LIBCPP_STD_VER > 11
1333template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1334#endif
1335
1336// add_volatile
1337
1338template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1339  typedef _LIBCPP_NODEBUG_TYPE volatile _Tp type;
1340};
1341
1342#if _LIBCPP_STD_VER > 11
1343template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1344#endif
1345
1346// add_cv
1347template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1348  typedef _LIBCPP_NODEBUG_TYPE const volatile _Tp type;
1349};
1350
1351#if _LIBCPP_STD_VER > 11
1352template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1353#endif
1354
1355// remove_reference
1356
1357#if __has_keyword(__remove_reference)
1358
1359template<class _Tp>
1360struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1361
1362#else // __has_keyword(__remove_reference)
1363
1364template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1365template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1366template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1367
1368#if _LIBCPP_STD_VER > 11
1369template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1370#endif
1371
1372#endif // __has_keyword(__remove_reference)
1373
1374// add_lvalue_reference
1375
1376template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE _Tp  type; };
1377template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
1378
1379template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1380{typedef _LIBCPP_NODEBUG_TYPE typename  __add_lvalue_reference_impl<_Tp>::type type;};
1381
1382#if _LIBCPP_STD_VER > 11
1383template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1384#endif
1385
1386template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE  _Tp   type; };
1387template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE  _Tp&& type; };
1388
1389template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1390{typedef _LIBCPP_NODEBUG_TYPE  typename __add_rvalue_reference_impl<_Tp>::type type;};
1391
1392#if _LIBCPP_STD_VER > 11
1393template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1394#endif
1395
1396// Suppress deprecation notice for volatile-qualified return type resulting
1397// from volatile-qualified types _Tp.
1398_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1399template <class _Tp> _Tp&& __declval(int);
1400template <class _Tp> _Tp   __declval(long);
1401_LIBCPP_SUPPRESS_DEPRECATED_POP
1402
1403template <class _Tp>
1404decltype(_VSTD::__declval<_Tp>(0))
1405declval() _NOEXCEPT;
1406
1407// __uncvref
1408
1409template <class _Tp>
1410struct __uncvref  {
1411    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1412};
1413
1414template <class _Tp>
1415struct __unconstref {
1416    typedef _LIBCPP_NODEBUG_TYPE typename remove_const<typename remove_reference<_Tp>::type>::type type;
1417};
1418
1419#ifndef _LIBCPP_CXX03_LANG
1420template <class _Tp>
1421using __uncvref_t _LIBCPP_NODEBUG_TYPE = typename __uncvref<_Tp>::type;
1422#endif
1423
1424// __is_same_uncvref
1425
1426template <class _Tp, class _Up>
1427struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1428                                   typename __uncvref<_Up>::type> {};
1429
1430#if _LIBCPP_STD_VER > 17
1431// remove_cvref - same as __uncvref
1432template <class _Tp>
1433struct remove_cvref : public __uncvref<_Tp> {};
1434
1435template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1436#endif
1437
1438
1439struct __any
1440{
1441    __any(...);
1442};
1443
1444// remove_pointer
1445
1446template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1447template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1448template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1449template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1450template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1451
1452#if _LIBCPP_STD_VER > 11
1453template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1454#endif
1455
1456// add_pointer
1457
1458template <class _Tp,
1459        bool = __is_referenceable<_Tp>::value ||
1460                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1461struct __add_pointer_impl
1462    {typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type* type;};
1463template <class _Tp> struct __add_pointer_impl<_Tp, false>
1464    {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1465
1466template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1467    {typedef _LIBCPP_NODEBUG_TYPE typename __add_pointer_impl<_Tp>::type type;};
1468
1469#if _LIBCPP_STD_VER > 11
1470template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1471#endif
1472
1473// type_identity
1474#if _LIBCPP_STD_VER > 17
1475template<class _Tp> struct type_identity { typedef _Tp type; };
1476template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1477#endif
1478
1479// is_signed
1480
1481// In clang 9 and earlier, this builtin did not work for floating points or enums
1482#if __has_keyword(__is_signed) && _LIBCPP_CLANG_VER > 900
1483
1484template<class _Tp>
1485struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1486
1487#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1488template <class _Tp>
1489_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v = __is_signed(_Tp);
1490#endif
1491
1492#else // __has_keyword(__is_signed)
1493
1494template <class _Tp, bool = is_integral<_Tp>::value>
1495struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1496
1497template <class _Tp>
1498struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1499
1500template <class _Tp, bool = is_arithmetic<_Tp>::value>
1501struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1502
1503template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1504
1505template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1506
1507#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1508template <class _Tp>
1509_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v
1510    = is_signed<_Tp>::value;
1511#endif
1512
1513#endif // __has_keyword(__is_signed)
1514
1515// is_unsigned
1516
1517#if __has_keyword(__is_unsigned)
1518
1519template<class _Tp>
1520struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
1521
1522#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1523template <class _Tp>
1524_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v = __is_unsigned(_Tp);
1525#endif
1526
1527#else // __has_keyword(__is_unsigned)
1528
1529template <class _Tp, bool = is_integral<_Tp>::value>
1530struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1531
1532template <class _Tp>
1533struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1534
1535template <class _Tp, bool = is_arithmetic<_Tp>::value>
1536struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1537
1538template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1539
1540template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1541
1542#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1543template <class _Tp>
1544_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v
1545    = is_unsigned<_Tp>::value;
1546#endif
1547
1548#endif // __has_keyword(__is_unsigned)
1549
1550// rank
1551
1552template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1553    : public integral_constant<size_t, 0> {};
1554template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1555    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1556template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1557    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1558
1559#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1560template <class _Tp>
1561_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t rank_v
1562    = rank<_Tp>::value;
1563#endif
1564
1565// extent
1566
1567#if __has_keyword(__array_extent)
1568
1569template<class _Tp, size_t _Dim = 0>
1570struct _LIBCPP_TEMPLATE_VIS extent
1571    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1572
1573#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1574template <class _Tp, unsigned _Ip = 0>
1575_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v = __array_extent(_Tp, _Ip);
1576#endif
1577
1578#else // __has_keyword(__array_extent)
1579
1580template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1581    : public integral_constant<size_t, 0> {};
1582template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1583    : public integral_constant<size_t, 0> {};
1584template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1585    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1586template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1587    : public integral_constant<size_t, _Np> {};
1588template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1589    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1590
1591#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1592template <class _Tp, unsigned _Ip = 0>
1593_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v
1594    = extent<_Tp, _Ip>::value;
1595#endif
1596
1597#endif // __has_keyword(__array_extent)
1598
1599// remove_extent
1600
1601template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1602    {typedef _Tp type;};
1603template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1604    {typedef _Tp type;};
1605template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1606    {typedef _Tp type;};
1607
1608#if _LIBCPP_STD_VER > 11
1609template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1610#endif
1611
1612// remove_all_extents
1613
1614template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1615    {typedef _Tp type;};
1616template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1617    {typedef typename remove_all_extents<_Tp>::type type;};
1618template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1619    {typedef typename remove_all_extents<_Tp>::type type;};
1620
1621#if _LIBCPP_STD_VER > 11
1622template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1623#endif
1624
1625#if _LIBCPP_STD_VER > 17
1626// is_bounded_array
1627
1628template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1629template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1630
1631template <class _Tp>
1632_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1633bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1634
1635// is_unbounded_array
1636
1637template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1638template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1639
1640template <class _Tp>
1641_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1642bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1643#endif
1644
1645// decay
1646
1647template <class _Up, bool>
1648struct __decay {
1649    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<_Up>::type type;
1650};
1651
1652template <class _Up>
1653struct __decay<_Up, true> {
1654public:
1655    typedef _LIBCPP_NODEBUG_TYPE typename conditional
1656                     <
1657                         is_array<_Up>::value,
1658                         typename remove_extent<_Up>::type*,
1659                         typename conditional
1660                         <
1661                              is_function<_Up>::value,
1662                              typename add_pointer<_Up>::type,
1663                              typename remove_cv<_Up>::type
1664                         >::type
1665                     >::type type;
1666};
1667
1668template <class _Tp>
1669struct _LIBCPP_TEMPLATE_VIS decay
1670{
1671private:
1672    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
1673public:
1674    typedef _LIBCPP_NODEBUG_TYPE typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1675};
1676
1677#if _LIBCPP_STD_VER > 11
1678template <class _Tp> using decay_t = typename decay<_Tp>::type;
1679#endif
1680
1681// is_abstract
1682
1683template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1684    : public integral_constant<bool, __is_abstract(_Tp)> {};
1685
1686#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1687template <class _Tp>
1688_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_abstract_v
1689    = is_abstract<_Tp>::value;
1690#endif
1691
1692// is_final
1693
1694template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1695__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1696
1697#if _LIBCPP_STD_VER > 11
1698template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1699is_final : public integral_constant<bool, __is_final(_Tp)> {};
1700#endif
1701
1702#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1703template <class _Tp>
1704_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_final_v
1705    = is_final<_Tp>::value;
1706#endif
1707
1708// is_aggregate
1709#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1710
1711template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1712is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1713
1714#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1715template <class _Tp>
1716_LIBCPP_INLINE_VAR constexpr bool is_aggregate_v
1717    = is_aggregate<_Tp>::value;
1718#endif
1719
1720#endif // _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1721
1722// is_base_of
1723
1724template <class _Bp, class _Dp>
1725struct _LIBCPP_TEMPLATE_VIS is_base_of
1726    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1727
1728#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1729template <class _Bp, class _Dp>
1730_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_base_of_v
1731    = is_base_of<_Bp, _Dp>::value;
1732#endif
1733
1734// is_convertible
1735
1736#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1737
1738template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1739    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1740
1741#else  // __has_feature(is_convertible_to)
1742
1743namespace __is_convertible_imp
1744{
1745template <class _Tp> void  __test_convert(_Tp);
1746
1747template <class _From, class _To, class = void>
1748struct __is_convertible_test : public false_type {};
1749
1750template <class _From, class _To>
1751struct __is_convertible_test<_From, _To,
1752    decltype(_VSTD::__is_convertible_imp::__test_convert<_To>(_VSTD::declval<_From>()))> : public true_type
1753{};
1754
1755template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1756                     bool _IsFunction = is_function<_Tp>::value,
1757                     bool _IsVoid =     is_void<_Tp>::value>
1758                     struct __is_array_function_or_void                          {enum {value = 0};};
1759template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1760template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1761template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1762}
1763
1764template <class _Tp,
1765    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1766struct __is_convertible_check
1767{
1768    static const size_t __v = 0;
1769};
1770
1771template <class _Tp>
1772struct __is_convertible_check<_Tp, 0>
1773{
1774    static const size_t __v = sizeof(_Tp);
1775};
1776
1777template <class _T1, class _T2,
1778    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1779    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1780struct __is_convertible
1781    : public integral_constant<bool,
1782        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1783    >
1784{};
1785
1786template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1787template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1788template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1789template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1790
1791template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1792template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1793template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1794template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1795
1796template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1797template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1798template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1799template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1800
1801template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1802    : public __is_convertible<_T1, _T2>
1803{
1804    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1805    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1806};
1807
1808#endif  // __has_feature(is_convertible_to)
1809
1810#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1811template <class _From, class _To>
1812_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_convertible_v
1813    = is_convertible<_From, _To>::value;
1814#endif
1815
1816// is_nothrow_convertible
1817
1818#if _LIBCPP_STD_VER > 17
1819
1820template <typename _Tp>
1821static void __test_noexcept(_Tp) noexcept;
1822
1823template<typename _Fm, typename _To>
1824static bool_constant<noexcept(__test_noexcept<_To>(declval<_Fm>()))>
1825__is_nothrow_convertible_test();
1826
1827template <typename _Fm, typename _To>
1828struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1829{ };
1830
1831template <typename _Fm, typename _To>
1832struct is_nothrow_convertible : _Or<
1833    _And<is_void<_To>, is_void<_Fm>>,
1834    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1835>::type { };
1836
1837template <typename _Fm, typename _To>
1838inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1839
1840#endif // _LIBCPP_STD_VER > 17
1841
1842// is_empty
1843
1844#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1845
1846template <class _Tp>
1847struct _LIBCPP_TEMPLATE_VIS is_empty
1848    : public integral_constant<bool, __is_empty(_Tp)> {};
1849
1850#else  // __has_feature(is_empty)
1851
1852template <class _Tp>
1853struct __is_empty1
1854    : public _Tp
1855{
1856    double __lx;
1857};
1858
1859struct __is_empty2
1860{
1861    double __lx;
1862};
1863
1864template <class _Tp, bool = is_class<_Tp>::value>
1865struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1866
1867template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1868
1869template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1870
1871#endif  // __has_feature(is_empty)
1872
1873#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1874template <class _Tp>
1875_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_empty_v
1876    = is_empty<_Tp>::value;
1877#endif
1878
1879// is_polymorphic
1880
1881#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1882
1883template <class _Tp>
1884struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1885    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1886
1887#else
1888
1889template<typename _Tp> char &__is_polymorphic_impl(
1890    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1891                       int>::type);
1892template<typename _Tp> __two &__is_polymorphic_impl(...);
1893
1894template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1895    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1896
1897#endif // __has_feature(is_polymorphic)
1898
1899#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1900template <class _Tp>
1901_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_polymorphic_v
1902    = is_polymorphic<_Tp>::value;
1903#endif
1904
1905// has_virtual_destructor
1906
1907#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1908
1909template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1910    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1911
1912#else
1913
1914template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1915    : public false_type {};
1916
1917#endif
1918
1919#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1920template <class _Tp>
1921_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_virtual_destructor_v
1922    = has_virtual_destructor<_Tp>::value;
1923#endif
1924
1925// has_unique_object_representations
1926
1927#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_UNIQUE_OBJECT_REPRESENTATIONS)
1928
1929template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1930    : public integral_constant<bool,
1931       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1932
1933#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1934template <class _Tp>
1935_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_unique_object_representations_v
1936    = has_unique_object_representations<_Tp>::value;
1937#endif
1938
1939#endif
1940
1941// alignment_of
1942
1943template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1944    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1945
1946#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1947template <class _Tp>
1948_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t alignment_of_v
1949    = alignment_of<_Tp>::value;
1950#endif
1951
1952// aligned_storage
1953
1954template <class _Hp, class _Tp>
1955struct __type_list
1956{
1957    typedef _Hp _Head;
1958    typedef _Tp _Tail;
1959};
1960
1961struct __nat
1962{
1963#ifndef _LIBCPP_CXX03_LANG
1964    __nat() = delete;
1965    __nat(const __nat&) = delete;
1966    __nat& operator=(const __nat&) = delete;
1967    ~__nat() = delete;
1968#endif
1969};
1970
1971template <class _Tp>
1972struct __align_type
1973{
1974    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1975    typedef _Tp type;
1976};
1977
1978struct __struct_double {long double __lx;};
1979struct __struct_double4 {double __lx[4];};
1980
1981typedef
1982    __type_list<__align_type<unsigned char>,
1983    __type_list<__align_type<unsigned short>,
1984    __type_list<__align_type<unsigned int>,
1985    __type_list<__align_type<unsigned long>,
1986    __type_list<__align_type<unsigned long long>,
1987    __type_list<__align_type<double>,
1988    __type_list<__align_type<long double>,
1989    __type_list<__align_type<__struct_double>,
1990    __type_list<__align_type<__struct_double4>,
1991    __type_list<__align_type<int*>,
1992    __nat
1993    > > > > > > > > > > __all_types;
1994
1995template <size_t _Align>
1996struct _ALIGNAS(_Align) __fallback_overaligned {};
1997
1998template <class _TL, size_t _Align> struct __find_pod;
1999
2000template <class _Hp, size_t _Align>
2001struct __find_pod<__type_list<_Hp, __nat>, _Align>
2002{
2003    typedef typename conditional<
2004                             _Align == _Hp::value,
2005                             typename _Hp::type,
2006                             __fallback_overaligned<_Align>
2007                         >::type type;
2008};
2009
2010template <class _Hp, class _Tp, size_t _Align>
2011struct __find_pod<__type_list<_Hp, _Tp>, _Align>
2012{
2013    typedef typename conditional<
2014                             _Align == _Hp::value,
2015                             typename _Hp::type,
2016                             typename __find_pod<_Tp, _Align>::type
2017                         >::type type;
2018};
2019
2020template <class _TL, size_t _Len> struct __find_max_align;
2021
2022template <class _Hp, size_t _Len>
2023struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
2024
2025template <size_t _Len, size_t _A1, size_t _A2>
2026struct __select_align
2027{
2028private:
2029    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
2030    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
2031public:
2032    static const size_t value = _Len < __max ? __min : __max;
2033};
2034
2035template <class _Hp, class _Tp, size_t _Len>
2036struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
2037    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
2038
2039template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2040struct _LIBCPP_TEMPLATE_VIS aligned_storage
2041{
2042    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
2043    union type
2044    {
2045        _Aligner __align;
2046        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
2047    };
2048};
2049
2050#if _LIBCPP_STD_VER > 11
2051template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2052    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
2053#endif
2054
2055#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
2056template <size_t _Len>\
2057struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
2058{\
2059    struct _ALIGNAS(n) type\
2060    {\
2061        unsigned char __lx[(_Len + n - 1)/n * n];\
2062    };\
2063}
2064
2065_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2066_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2067_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2068_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2069_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2070_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2071_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2072_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2073_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2074_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2075_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2076_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2077_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2078_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2079// PE/COFF does not support alignment beyond 8192 (=0x2000)
2080#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2081_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2082#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2083
2084#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2085
2086
2087// aligned_union
2088
2089template <size_t _I0, size_t ..._In>
2090struct __static_max;
2091
2092template <size_t _I0>
2093struct __static_max<_I0>
2094{
2095    static const size_t value = _I0;
2096};
2097
2098template <size_t _I0, size_t _I1, size_t ..._In>
2099struct __static_max<_I0, _I1, _In...>
2100{
2101    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2102                                             __static_max<_I1, _In...>::value;
2103};
2104
2105template <size_t _Len, class _Type0, class ..._Types>
2106struct aligned_union
2107{
2108    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2109                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2110    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2111                                             sizeof(_Types)...>::value;
2112    typedef typename aligned_storage<__len, alignment_value>::type type;
2113};
2114
2115#if _LIBCPP_STD_VER > 11
2116template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2117#endif
2118
2119template <class _Tp>
2120struct __numeric_type
2121{
2122   static void __test(...);
2123   static float __test(float);
2124   static double __test(char);
2125   static double __test(int);
2126   static double __test(unsigned);
2127   static double __test(long);
2128   static double __test(unsigned long);
2129   static double __test(long long);
2130   static double __test(unsigned long long);
2131   static double __test(double);
2132   static long double __test(long double);
2133
2134   typedef decltype(__test(declval<_Tp>())) type;
2135   static const bool value = _IsNotSame<type, void>::value;
2136};
2137
2138template <>
2139struct __numeric_type<void>
2140{
2141   static const bool value = true;
2142};
2143
2144// __promote
2145
2146template <class _A1, class _A2 = void, class _A3 = void,
2147          bool = __numeric_type<_A1>::value &&
2148                 __numeric_type<_A2>::value &&
2149                 __numeric_type<_A3>::value>
2150class __promote_imp
2151{
2152public:
2153    static const bool value = false;
2154};
2155
2156template <class _A1, class _A2, class _A3>
2157class __promote_imp<_A1, _A2, _A3, true>
2158{
2159private:
2160    typedef typename __promote_imp<_A1>::type __type1;
2161    typedef typename __promote_imp<_A2>::type __type2;
2162    typedef typename __promote_imp<_A3>::type __type3;
2163public:
2164    typedef decltype(__type1() + __type2() + __type3()) type;
2165    static const bool value = true;
2166};
2167
2168template <class _A1, class _A2>
2169class __promote_imp<_A1, _A2, void, true>
2170{
2171private:
2172    typedef typename __promote_imp<_A1>::type __type1;
2173    typedef typename __promote_imp<_A2>::type __type2;
2174public:
2175    typedef decltype(__type1() + __type2()) type;
2176    static const bool value = true;
2177};
2178
2179template <class _A1>
2180class __promote_imp<_A1, void, void, true>
2181{
2182public:
2183    typedef typename __numeric_type<_A1>::type type;
2184    static const bool value = true;
2185};
2186
2187template <class _A1, class _A2 = void, class _A3 = void>
2188class __promote : public __promote_imp<_A1, _A2, _A3> {};
2189
2190// make_signed / make_unsigned
2191
2192typedef
2193    __type_list<signed char,
2194    __type_list<signed short,
2195    __type_list<signed int,
2196    __type_list<signed long,
2197    __type_list<signed long long,
2198#ifndef _LIBCPP_HAS_NO_INT128
2199    __type_list<__int128_t,
2200#endif
2201    __nat
2202#ifndef _LIBCPP_HAS_NO_INT128
2203    >
2204#endif
2205    > > > > > __signed_types;
2206
2207typedef
2208    __type_list<unsigned char,
2209    __type_list<unsigned short,
2210    __type_list<unsigned int,
2211    __type_list<unsigned long,
2212    __type_list<unsigned long long,
2213#ifndef _LIBCPP_HAS_NO_INT128
2214    __type_list<__uint128_t,
2215#endif
2216    __nat
2217#ifndef _LIBCPP_HAS_NO_INT128
2218    >
2219#endif
2220    > > > > > __unsigned_types;
2221
2222template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2223
2224template <class _Hp, class _Tp, size_t _Size>
2225struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2226{
2227    typedef _LIBCPP_NODEBUG_TYPE _Hp type;
2228};
2229
2230template <class _Hp, class _Tp, size_t _Size>
2231struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2232{
2233    typedef _LIBCPP_NODEBUG_TYPE typename __find_first<_Tp, _Size>::type type;
2234};
2235
2236template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2237                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2238struct __apply_cv
2239{
2240    typedef _LIBCPP_NODEBUG_TYPE _Up type;
2241};
2242
2243template <class _Tp, class _Up>
2244struct __apply_cv<_Tp, _Up, true, false>
2245{
2246    typedef _LIBCPP_NODEBUG_TYPE const _Up type;
2247};
2248
2249template <class _Tp, class _Up>
2250struct __apply_cv<_Tp, _Up, false, true>
2251{
2252    typedef volatile _Up type;
2253};
2254
2255template <class _Tp, class _Up>
2256struct __apply_cv<_Tp, _Up, true, true>
2257{
2258    typedef const volatile _Up type;
2259};
2260
2261template <class _Tp, class _Up>
2262struct __apply_cv<_Tp&, _Up, false, false>
2263{
2264    typedef _Up& type;
2265};
2266
2267template <class _Tp, class _Up>
2268struct __apply_cv<_Tp&, _Up, true, false>
2269{
2270    typedef const _Up& type;
2271};
2272
2273template <class _Tp, class _Up>
2274struct __apply_cv<_Tp&, _Up, false, true>
2275{
2276    typedef volatile _Up& type;
2277};
2278
2279template <class _Tp, class _Up>
2280struct __apply_cv<_Tp&, _Up, true, true>
2281{
2282    typedef const volatile _Up& type;
2283};
2284
2285template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2286struct __make_signed {};
2287
2288template <class _Tp>
2289struct __make_signed<_Tp, true>
2290{
2291    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2292};
2293
2294template <> struct __make_signed<bool,               true> {};
2295template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2296template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2297template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2298template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2299template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2300template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2301template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2302template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2303#ifndef _LIBCPP_HAS_NO_INT128
2304template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2305template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2306#endif
2307
2308template <class _Tp>
2309struct _LIBCPP_TEMPLATE_VIS make_signed
2310{
2311    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2312};
2313
2314#if _LIBCPP_STD_VER > 11
2315template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2316#endif
2317
2318template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2319struct __make_unsigned {};
2320
2321template <class _Tp>
2322struct __make_unsigned<_Tp, true>
2323{
2324    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2325};
2326
2327template <> struct __make_unsigned<bool,               true> {};
2328template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2329template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2330template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2331template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2332template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2333template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2334template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2335template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2336#ifndef _LIBCPP_HAS_NO_INT128
2337template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2338template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2339#endif
2340
2341template <class _Tp>
2342struct _LIBCPP_TEMPLATE_VIS make_unsigned
2343{
2344    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2345};
2346
2347#if _LIBCPP_STD_VER > 11
2348template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2349#endif
2350
2351#if _LIBCPP_STD_VER > 14
2352template <class...> using void_t = void;
2353#endif
2354
2355#if _LIBCPP_STD_VER > 17
2356// Let COND_RES(X, Y) be:
2357template <class _Tp, class _Up>
2358using __cond_type = decltype(false ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>());
2359
2360template <class _Tp, class _Up, class = void>
2361struct __common_type3 {};
2362
2363// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
2364template <class _Tp, class _Up>
2365struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
2366{
2367    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
2368};
2369
2370template <class _Tp, class _Up, class = void>
2371struct __common_type2_imp : __common_type3<_Tp, _Up> {};
2372#else
2373template <class _Tp, class _Up, class = void>
2374struct __common_type2_imp {};
2375#endif
2376
2377// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
2378template <class _Tp, class _Up>
2379struct __common_type2_imp<_Tp, _Up,
2380                          typename __void_t<decltype(
2381                                            true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2382                                            )>::type>
2383{
2384  typedef _LIBCPP_NODEBUG_TYPE typename decay<decltype(
2385                         true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2386                         )>::type type;
2387};
2388
2389template <class, class = void>
2390struct __common_type_impl {};
2391
2392// Clang provides variadic templates in C++03 as an extension.
2393#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2394# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2395template <class... Tp>
2396struct __common_types;
2397template <class... _Tp>
2398struct _LIBCPP_TEMPLATE_VIS common_type;
2399#else
2400# define _LIBCPP_OPTIONAL_PACK(...)
2401struct __no_arg;
2402template <class _Tp, class _Up, class = __no_arg>
2403struct __common_types;
2404template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2405          class _Unused = __no_arg>
2406struct common_type {
2407  static_assert(sizeof(_Unused) == 0,
2408                "common_type accepts at most 3 arguments in C++03");
2409};
2410#endif // _LIBCPP_CXX03_LANG
2411
2412template <class _Tp, class _Up>
2413struct __common_type_impl<
2414    __common_types<_Tp, _Up>,
2415    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2416{
2417  typedef typename common_type<_Tp, _Up>::type type;
2418};
2419
2420template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2421struct __common_type_impl<
2422    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2423    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2424    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2425                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2426};
2427
2428// bullet 1 - sizeof...(Tp) == 0
2429
2430template <>
2431struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2432
2433// bullet 2 - sizeof...(Tp) == 1
2434
2435template <class _Tp>
2436struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2437    : public common_type<_Tp, _Tp> {};
2438
2439// bullet 3 - sizeof...(Tp) == 2
2440
2441// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
2442template <class _Tp, class _Up>
2443struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2444    : conditional<
2445        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2446        __common_type2_imp<_Tp, _Up>,
2447        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2448    >::type
2449{};
2450
2451// bullet 4 - sizeof...(Tp) > 2
2452
2453template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2454struct _LIBCPP_TEMPLATE_VIS
2455    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2456    : __common_type_impl<
2457          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2458
2459#undef _LIBCPP_OPTIONAL_PACK
2460
2461#if _LIBCPP_STD_VER > 11
2462template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2463#endif
2464
2465// is_assignable
2466
2467template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
2468
2469#if __has_keyword(__is_assignable)
2470
2471template<class _Tp, class _Up>
2472struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2473
2474#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2475template <class _Tp, class _Arg>
2476_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v = __is_assignable(_Tp, _Arg);
2477#endif
2478
2479#else // __has_keyword(__is_assignable)
2480
2481template <class _Tp, class _Arg>
2482typename __select_2nd<decltype((_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>())), true_type>::type
2483__is_assignable_test(int);
2484
2485template <class, class>
2486false_type __is_assignable_test(...);
2487
2488
2489template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2490struct __is_assignable_imp
2491    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2492
2493template <class _Tp, class _Arg>
2494struct __is_assignable_imp<_Tp, _Arg, true>
2495    : public false_type
2496{
2497};
2498
2499template <class _Tp, class _Arg>
2500struct is_assignable
2501    : public __is_assignable_imp<_Tp, _Arg> {};
2502
2503#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2504template <class _Tp, class _Arg>
2505_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v
2506    = is_assignable<_Tp, _Arg>::value;
2507#endif
2508
2509#endif  // __has_keyword(__is_assignable)
2510
2511// is_copy_assignable
2512
2513template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2514    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2515                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2516
2517#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2518template <class _Tp>
2519_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_assignable_v
2520    = is_copy_assignable<_Tp>::value;
2521#endif
2522
2523// is_move_assignable
2524
2525template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2526    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2527                           typename add_rvalue_reference<_Tp>::type> {};
2528
2529#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2530template <class _Tp>
2531_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_assignable_v
2532    = is_move_assignable<_Tp>::value;
2533#endif
2534
2535// is_destructible
2536
2537#if __has_keyword(__is_destructible)
2538
2539template<class _Tp>
2540struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2541
2542#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2543template <class _Tp>
2544_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v = __is_destructible(_Tp);
2545#endif
2546
2547#else // __has_keyword(__is_destructible)
2548
2549//  if it's a reference, return true
2550//  if it's a function, return false
2551//  if it's   void,     return false
2552//  if it's an array of unknown bound, return false
2553//  Otherwise, return "std::declval<_Up&>().~_Up()" is well-formed
2554//    where _Up is remove_all_extents<_Tp>::type
2555
2556template <class>
2557struct __is_destructible_apply { typedef int type; };
2558
2559template <typename _Tp>
2560struct __is_destructor_wellformed {
2561    template <typename _Tp1>
2562    static char  __test (
2563        typename __is_destructible_apply<decltype(_VSTD::declval<_Tp1&>().~_Tp1())>::type
2564    );
2565
2566    template <typename _Tp1>
2567    static __two __test (...);
2568
2569    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2570};
2571
2572template <class _Tp, bool>
2573struct __destructible_imp;
2574
2575template <class _Tp>
2576struct __destructible_imp<_Tp, false>
2577   : public _VSTD::integral_constant<bool,
2578        __is_destructor_wellformed<typename _VSTD::remove_all_extents<_Tp>::type>::value> {};
2579
2580template <class _Tp>
2581struct __destructible_imp<_Tp, true>
2582    : public _VSTD::true_type {};
2583
2584template <class _Tp, bool>
2585struct __destructible_false;
2586
2587template <class _Tp>
2588struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, _VSTD::is_reference<_Tp>::value> {};
2589
2590template <class _Tp>
2591struct __destructible_false<_Tp, true> : public _VSTD::false_type {};
2592
2593template <class _Tp>
2594struct is_destructible
2595    : public __destructible_false<_Tp, _VSTD::is_function<_Tp>::value> {};
2596
2597template <class _Tp>
2598struct is_destructible<_Tp[]>
2599    : public _VSTD::false_type {};
2600
2601template <>
2602struct is_destructible<void>
2603    : public _VSTD::false_type {};
2604
2605#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2606template <class _Tp>
2607_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v
2608    = is_destructible<_Tp>::value;
2609#endif
2610
2611#endif // __has_keyword(__is_destructible)
2612
2613// move
2614
2615template <class _Tp>
2616inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2617typename remove_reference<_Tp>::type&&
2618move(_Tp&& __t) _NOEXCEPT
2619{
2620    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
2621    return static_cast<_Up&&>(__t);
2622}
2623
2624template <class _Tp>
2625inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2626_Tp&&
2627forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT
2628{
2629    return static_cast<_Tp&&>(__t);
2630}
2631
2632template <class _Tp>
2633inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2634_Tp&&
2635forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT
2636{
2637    static_assert(!is_lvalue_reference<_Tp>::value,
2638                  "can not forward an rvalue as an lvalue");
2639    return static_cast<_Tp&&>(__t);
2640}
2641
2642template <class _Tp>
2643inline _LIBCPP_INLINE_VISIBILITY
2644typename decay<_Tp>::type
2645__decay_copy(_Tp&& __t)
2646{
2647    return _VSTD::forward<_Tp>(__t);
2648}
2649
2650template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2651struct __member_pointer_traits_imp
2652{
2653};
2654
2655template <class _Rp, class _Class, class ..._Param>
2656struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2657{
2658    typedef _Class _ClassType;
2659    typedef _Rp _ReturnType;
2660    typedef _Rp (_FnType) (_Param...);
2661};
2662
2663template <class _Rp, class _Class, class ..._Param>
2664struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2665{
2666    typedef _Class _ClassType;
2667    typedef _Rp _ReturnType;
2668    typedef _Rp (_FnType) (_Param..., ...);
2669};
2670
2671template <class _Rp, class _Class, class ..._Param>
2672struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2673{
2674    typedef _Class const _ClassType;
2675    typedef _Rp _ReturnType;
2676    typedef _Rp (_FnType) (_Param...);
2677};
2678
2679template <class _Rp, class _Class, class ..._Param>
2680struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2681{
2682    typedef _Class const _ClassType;
2683    typedef _Rp _ReturnType;
2684    typedef _Rp (_FnType) (_Param..., ...);
2685};
2686
2687template <class _Rp, class _Class, class ..._Param>
2688struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2689{
2690    typedef _Class volatile _ClassType;
2691    typedef _Rp _ReturnType;
2692    typedef _Rp (_FnType) (_Param...);
2693};
2694
2695template <class _Rp, class _Class, class ..._Param>
2696struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2697{
2698    typedef _Class volatile _ClassType;
2699    typedef _Rp _ReturnType;
2700    typedef _Rp (_FnType) (_Param..., ...);
2701};
2702
2703template <class _Rp, class _Class, class ..._Param>
2704struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2705{
2706    typedef _Class const volatile _ClassType;
2707    typedef _Rp _ReturnType;
2708    typedef _Rp (_FnType) (_Param...);
2709};
2710
2711template <class _Rp, class _Class, class ..._Param>
2712struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2713{
2714    typedef _Class const volatile _ClassType;
2715    typedef _Rp _ReturnType;
2716    typedef _Rp (_FnType) (_Param..., ...);
2717};
2718
2719#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2720
2721template <class _Rp, class _Class, class ..._Param>
2722struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2723{
2724    typedef _Class& _ClassType;
2725    typedef _Rp _ReturnType;
2726    typedef _Rp (_FnType) (_Param...);
2727};
2728
2729template <class _Rp, class _Class, class ..._Param>
2730struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2731{
2732    typedef _Class& _ClassType;
2733    typedef _Rp _ReturnType;
2734    typedef _Rp (_FnType) (_Param..., ...);
2735};
2736
2737template <class _Rp, class _Class, class ..._Param>
2738struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2739{
2740    typedef _Class const& _ClassType;
2741    typedef _Rp _ReturnType;
2742    typedef _Rp (_FnType) (_Param...);
2743};
2744
2745template <class _Rp, class _Class, class ..._Param>
2746struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2747{
2748    typedef _Class const& _ClassType;
2749    typedef _Rp _ReturnType;
2750    typedef _Rp (_FnType) (_Param..., ...);
2751};
2752
2753template <class _Rp, class _Class, class ..._Param>
2754struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2755{
2756    typedef _Class volatile& _ClassType;
2757    typedef _Rp _ReturnType;
2758    typedef _Rp (_FnType) (_Param...);
2759};
2760
2761template <class _Rp, class _Class, class ..._Param>
2762struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2763{
2764    typedef _Class volatile& _ClassType;
2765    typedef _Rp _ReturnType;
2766    typedef _Rp (_FnType) (_Param..., ...);
2767};
2768
2769template <class _Rp, class _Class, class ..._Param>
2770struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2771{
2772    typedef _Class const volatile& _ClassType;
2773    typedef _Rp _ReturnType;
2774    typedef _Rp (_FnType) (_Param...);
2775};
2776
2777template <class _Rp, class _Class, class ..._Param>
2778struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2779{
2780    typedef _Class const volatile& _ClassType;
2781    typedef _Rp _ReturnType;
2782    typedef _Rp (_FnType) (_Param..., ...);
2783};
2784
2785template <class _Rp, class _Class, class ..._Param>
2786struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2787{
2788    typedef _Class&& _ClassType;
2789    typedef _Rp _ReturnType;
2790    typedef _Rp (_FnType) (_Param...);
2791};
2792
2793template <class _Rp, class _Class, class ..._Param>
2794struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2795{
2796    typedef _Class&& _ClassType;
2797    typedef _Rp _ReturnType;
2798    typedef _Rp (_FnType) (_Param..., ...);
2799};
2800
2801template <class _Rp, class _Class, class ..._Param>
2802struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2803{
2804    typedef _Class const&& _ClassType;
2805    typedef _Rp _ReturnType;
2806    typedef _Rp (_FnType) (_Param...);
2807};
2808
2809template <class _Rp, class _Class, class ..._Param>
2810struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2811{
2812    typedef _Class const&& _ClassType;
2813    typedef _Rp _ReturnType;
2814    typedef _Rp (_FnType) (_Param..., ...);
2815};
2816
2817template <class _Rp, class _Class, class ..._Param>
2818struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2819{
2820    typedef _Class volatile&& _ClassType;
2821    typedef _Rp _ReturnType;
2822    typedef _Rp (_FnType) (_Param...);
2823};
2824
2825template <class _Rp, class _Class, class ..._Param>
2826struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2827{
2828    typedef _Class volatile&& _ClassType;
2829    typedef _Rp _ReturnType;
2830    typedef _Rp (_FnType) (_Param..., ...);
2831};
2832
2833template <class _Rp, class _Class, class ..._Param>
2834struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2835{
2836    typedef _Class const volatile&& _ClassType;
2837    typedef _Rp _ReturnType;
2838    typedef _Rp (_FnType) (_Param...);
2839};
2840
2841template <class _Rp, class _Class, class ..._Param>
2842struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2843{
2844    typedef _Class const volatile&& _ClassType;
2845    typedef _Rp _ReturnType;
2846    typedef _Rp (_FnType) (_Param..., ...);
2847};
2848
2849#endif  // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2850
2851
2852template <class _Rp, class _Class>
2853struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2854{
2855    typedef _Class _ClassType;
2856    typedef _Rp _ReturnType;
2857};
2858
2859template <class _MP>
2860struct __member_pointer_traits
2861    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2862                    is_member_function_pointer<_MP>::value,
2863                    is_member_object_pointer<_MP>::value>
2864{
2865//     typedef ... _ClassType;
2866//     typedef ... _ReturnType;
2867//     typedef ... _FnType;
2868};
2869
2870
2871template <class _DecayedFp>
2872struct __member_pointer_class_type {};
2873
2874template <class _Ret, class _ClassType>
2875struct __member_pointer_class_type<_Ret _ClassType::*> {
2876  typedef _ClassType type;
2877};
2878
2879// result_of
2880
2881template <class _Callable> class result_of;
2882
2883#ifdef _LIBCPP_HAS_NO_VARIADICS
2884
2885template <class _Fn, bool, bool>
2886class __result_of
2887{
2888};
2889
2890template <class _Fn>
2891class __result_of<_Fn(), true, false>
2892{
2893public:
2894    typedef decltype(declval<_Fn>()()) type;
2895};
2896
2897template <class _Fn, class _A0>
2898class __result_of<_Fn(_A0), true, false>
2899{
2900public:
2901    typedef decltype(declval<_Fn>()(declval<_A0>())) type;
2902};
2903
2904template <class _Fn, class _A0, class _A1>
2905class __result_of<_Fn(_A0, _A1), true, false>
2906{
2907public:
2908    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>())) type;
2909};
2910
2911template <class _Fn, class _A0, class _A1, class _A2>
2912class __result_of<_Fn(_A0, _A1, _A2), true, false>
2913{
2914public:
2915    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>(), declval<_A2>())) type;
2916};
2917
2918template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
2919struct __result_of_mp;
2920
2921// member function pointer
2922
2923template <class _MP, class _Tp>
2924struct __result_of_mp<_MP, _Tp, true>
2925    : public __identity<typename __member_pointer_traits<_MP>::_ReturnType>
2926{
2927};
2928
2929// member data pointer
2930
2931template <class _MP, class _Tp, bool>
2932struct __result_of_mdp;
2933
2934template <class _Rp, class _Class, class _Tp>
2935struct __result_of_mdp<_Rp _Class::*, _Tp, false>
2936{
2937    typedef typename __apply_cv<decltype(*_VSTD::declval<_Tp>()), _Rp>::type& type;
2938};
2939
2940template <class _Rp, class _Class, class _Tp>
2941struct __result_of_mdp<_Rp _Class::*, _Tp, true>
2942{
2943    typedef typename __apply_cv<_Tp, _Rp>::type& type;
2944};
2945
2946template <class _Rp, class _Class, class _Tp>
2947struct __result_of_mp<_Rp _Class::*, _Tp, false>
2948    : public __result_of_mdp<_Rp _Class::*, _Tp,
2949            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
2950{
2951};
2952
2953
2954
2955template <class _Fn, class _Tp>
2956class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
2957    : public __result_of_mp<typename remove_reference<_Fn>::type,
2958                            _Tp,
2959                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2960{
2961};
2962
2963template <class _Fn, class _Tp, class _A0>
2964class __result_of<_Fn(_Tp, _A0), false, true>  // _Fn must be member pointer
2965    : public __result_of_mp<typename remove_reference<_Fn>::type,
2966                            _Tp,
2967                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2968{
2969};
2970
2971template <class _Fn, class _Tp, class _A0, class _A1>
2972class __result_of<_Fn(_Tp, _A0, _A1), false, true>  // _Fn must be member pointer
2973    : public __result_of_mp<typename remove_reference<_Fn>::type,
2974                            _Tp,
2975                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2976{
2977};
2978
2979template <class _Fn, class _Tp, class _A0, class _A1, class _A2>
2980class __result_of<_Fn(_Tp, _A0, _A1, _A2), false, true>  // _Fn must be member pointer
2981    : public __result_of_mp<typename remove_reference<_Fn>::type,
2982                            _Tp,
2983                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2984{
2985};
2986
2987// result_of
2988
2989template <class _Fn>
2990class _LIBCPP_TEMPLATE_VIS result_of<_Fn()>
2991    : public __result_of<_Fn(),
2992                         is_class<typename remove_reference<_Fn>::type>::value ||
2993                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2994                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2995                        >
2996{
2997};
2998
2999template <class _Fn, class _A0>
3000class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0)>
3001    : public __result_of<_Fn(_A0),
3002                         is_class<typename remove_reference<_Fn>::type>::value ||
3003                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3004                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3005                        >
3006{
3007};
3008
3009template <class _Fn, class _A0, class _A1>
3010class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0, _A1)>
3011    : public __result_of<_Fn(_A0, _A1),
3012                         is_class<typename remove_reference<_Fn>::type>::value ||
3013                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3014                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3015                        >
3016{
3017};
3018
3019template <class _Fn, class _A0, class _A1, class _A2>
3020class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0, _A1, _A2)>
3021    : public __result_of<_Fn(_A0, _A1, _A2),
3022                         is_class<typename remove_reference<_Fn>::type>::value ||
3023                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3024                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3025                        >
3026{
3027};
3028
3029#endif  // _LIBCPP_HAS_NO_VARIADICS
3030
3031// template <class T, class... Args> struct is_constructible;
3032
3033namespace __is_construct
3034{
3035struct __nat {};
3036}
3037
3038#if !defined(_LIBCPP_CXX03_LANG) && (!__has_feature(is_constructible) || \
3039    defined(_LIBCPP_TESTING_FALLBACK_IS_CONSTRUCTIBLE))
3040
3041template <class _Tp, class... _Args>
3042struct __libcpp_is_constructible;
3043
3044template <class _To, class _From>
3045struct __is_invalid_base_to_derived_cast {
3046  static_assert(is_reference<_To>::value, "Wrong specialization");
3047  using _RawFrom = __uncvref_t<_From>;
3048  using _RawTo = __uncvref_t<_To>;
3049  static const bool value = _And<
3050        _IsNotSame<_RawFrom, _RawTo>,
3051        is_base_of<_RawFrom, _RawTo>,
3052        _Not<__libcpp_is_constructible<_RawTo, _From>>
3053  >::value;
3054};
3055
3056template <class _To, class _From>
3057struct __is_invalid_lvalue_to_rvalue_cast : false_type {
3058  static_assert(is_reference<_To>::value, "Wrong specialization");
3059};
3060
3061template <class _ToRef, class _FromRef>
3062struct __is_invalid_lvalue_to_rvalue_cast<_ToRef&&, _FromRef&> {
3063  using _RawFrom = __uncvref_t<_FromRef>;
3064  using _RawTo = __uncvref_t<_ToRef>;
3065  static const bool value = _And<
3066      _Not<is_function<_RawTo>>,
3067      _Or<
3068        _IsSame<_RawFrom, _RawTo>,
3069        is_base_of<_RawTo, _RawFrom>>
3070    >::value;
3071};
3072
3073struct __is_constructible_helper
3074{
3075    template <class _To>
3076    static void __eat(_To);
3077
3078    // This overload is needed to work around a Clang bug that disallows
3079    // static_cast<T&&>(e) for non-reference-compatible types.
3080    // Example: static_cast<int&&>(declval<double>());
3081    // NOTE: The static_cast implementation below is required to support
3082    //  classes with explicit conversion operators.
3083    template <class _To, class _From,
3084              class = decltype(__eat<_To>(_VSTD::declval<_From>()))>
3085    static true_type __test_cast(int);
3086
3087    template <class _To, class _From,
3088              class = decltype(static_cast<_To>(_VSTD::declval<_From>()))>
3089    static integral_constant<bool,
3090        !__is_invalid_base_to_derived_cast<_To, _From>::value &&
3091        !__is_invalid_lvalue_to_rvalue_cast<_To, _From>::value
3092    > __test_cast(long);
3093
3094    template <class, class>
3095    static false_type __test_cast(...);
3096
3097    template <class _Tp, class ..._Args,
3098        class = decltype(_Tp(_VSTD::declval<_Args>()...))>
3099    static true_type __test_nary(int);
3100    template <class _Tp, class...>
3101    static false_type __test_nary(...);
3102
3103    template <class _Tp, class _A0, class = decltype(::new _Tp(_VSTD::declval<_A0>()))>
3104    static is_destructible<_Tp> __test_unary(int);
3105    template <class, class>
3106    static false_type __test_unary(...);
3107};
3108
3109template <class _Tp, bool = is_void<_Tp>::value>
3110struct __is_default_constructible
3111    : decltype(__is_constructible_helper::__test_nary<_Tp>(0))
3112{};
3113
3114template <class _Tp>
3115struct __is_default_constructible<_Tp, true> : false_type {};
3116
3117template <class _Tp>
3118struct __is_default_constructible<_Tp[], false> : false_type {};
3119
3120template <class _Tp, size_t _Nx>
3121struct __is_default_constructible<_Tp[_Nx], false>
3122    : __is_default_constructible<typename remove_all_extents<_Tp>::type>  {};
3123
3124template <class _Tp, class... _Args>
3125struct __libcpp_is_constructible
3126{
3127  static_assert(sizeof...(_Args) > 1, "Wrong specialization");
3128  typedef decltype(__is_constructible_helper::__test_nary<_Tp, _Args...>(0))
3129      type;
3130};
3131
3132template <class _Tp>
3133struct __libcpp_is_constructible<_Tp> : __is_default_constructible<_Tp> {};
3134
3135template <class _Tp, class _A0>
3136struct __libcpp_is_constructible<_Tp, _A0>
3137    : public decltype(__is_constructible_helper::__test_unary<_Tp, _A0>(0))
3138{};
3139
3140template <class _Tp, class _A0>
3141struct __libcpp_is_constructible<_Tp&, _A0>
3142    : public decltype(__is_constructible_helper::
3143    __test_cast<_Tp&, _A0>(0))
3144{};
3145
3146template <class _Tp, class _A0>
3147struct __libcpp_is_constructible<_Tp&&, _A0>
3148    : public decltype(__is_constructible_helper::
3149    __test_cast<_Tp&&, _A0>(0))
3150{};
3151
3152#endif
3153
3154#if __has_feature(is_constructible)
3155template <class _Tp, class ..._Args>
3156struct _LIBCPP_TEMPLATE_VIS is_constructible
3157    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
3158    {};
3159#else
3160template <class _Tp, class... _Args>
3161struct _LIBCPP_TEMPLATE_VIS is_constructible
3162    : public __libcpp_is_constructible<_Tp, _Args...>::type {};
3163#endif
3164
3165#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3166template <class _Tp, class ..._Args>
3167_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_constructible_v
3168    = is_constructible<_Tp, _Args...>::value;
3169#endif
3170
3171// is_default_constructible
3172
3173template <class _Tp>
3174struct _LIBCPP_TEMPLATE_VIS is_default_constructible
3175    : public is_constructible<_Tp>
3176    {};
3177
3178#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3179template <class _Tp>
3180_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_default_constructible_v
3181    = is_default_constructible<_Tp>::value;
3182#endif
3183
3184#ifndef _LIBCPP_CXX03_LANG
3185// First of all, we can't implement this check in C++03 mode because the {}
3186// default initialization syntax isn't valid.
3187// Second, we implement the trait in a funny manner with two defaulted template
3188// arguments to workaround Clang's PR43454.
3189template <class _Tp>
3190void __test_implicit_default_constructible(_Tp);
3191
3192template <class _Tp, class = void, bool = is_default_constructible<_Tp>::value>
3193struct __is_implicitly_default_constructible
3194    : false_type
3195{ };
3196
3197template <class _Tp>
3198struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true>
3199    : true_type
3200{ };
3201
3202template <class _Tp>
3203struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false>
3204    : false_type
3205{ };
3206#endif // !C++03
3207
3208// is_copy_constructible
3209
3210template <class _Tp>
3211struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
3212    : public is_constructible<_Tp,
3213                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3214
3215#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3216template <class _Tp>
3217_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_constructible_v
3218    = is_copy_constructible<_Tp>::value;
3219#endif
3220
3221// is_move_constructible
3222
3223template <class _Tp>
3224struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3225    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3226    {};
3227
3228#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3229template <class _Tp>
3230_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_constructible_v
3231    = is_move_constructible<_Tp>::value;
3232#endif
3233
3234// is_trivially_constructible
3235
3236#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3237
3238template <class _Tp, class... _Args>
3239struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3240    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3241{
3242};
3243
3244#else  // !__has_feature(is_trivially_constructible)
3245
3246template <class _Tp, class... _Args>
3247struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3248    : false_type
3249{
3250};
3251
3252template <class _Tp>
3253struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp>
3254#if __has_feature(has_trivial_constructor) || defined(_LIBCPP_COMPILER_GCC)
3255    : integral_constant<bool, __has_trivial_constructor(_Tp)>
3256#else
3257    : integral_constant<bool, is_scalar<_Tp>::value>
3258#endif
3259{
3260};
3261
3262template <class _Tp>
3263struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&&>
3264    : integral_constant<bool, is_scalar<_Tp>::value>
3265{
3266};
3267
3268template <class _Tp>
3269struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, const _Tp&>
3270    : integral_constant<bool, is_scalar<_Tp>::value>
3271{
3272};
3273
3274template <class _Tp>
3275struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&>
3276    : integral_constant<bool, is_scalar<_Tp>::value>
3277{
3278};
3279
3280#endif  // !__has_feature(is_trivially_constructible)
3281
3282
3283#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3284template <class _Tp, class... _Args>
3285_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_constructible_v
3286    = is_trivially_constructible<_Tp, _Args...>::value;
3287#endif
3288
3289// is_trivially_default_constructible
3290
3291template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3292    : public is_trivially_constructible<_Tp>
3293    {};
3294
3295#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3296template <class _Tp>
3297_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_default_constructible_v
3298    = is_trivially_default_constructible<_Tp>::value;
3299#endif
3300
3301// is_trivially_copy_constructible
3302
3303template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3304    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3305    {};
3306
3307#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3308template <class _Tp>
3309_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_constructible_v
3310    = is_trivially_copy_constructible<_Tp>::value;
3311#endif
3312
3313// is_trivially_move_constructible
3314
3315template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3316    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3317    {};
3318
3319#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3320template <class _Tp>
3321_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_constructible_v
3322    = is_trivially_move_constructible<_Tp>::value;
3323#endif
3324
3325// is_trivially_assignable
3326
3327#if __has_feature(is_trivially_assignable) || _GNUC_VER >= 501
3328
3329template <class _Tp, class _Arg>
3330struct is_trivially_assignable
3331    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3332{
3333};
3334
3335#else  // !__has_feature(is_trivially_assignable)
3336
3337template <class _Tp, class _Arg>
3338struct is_trivially_assignable
3339    : public false_type {};
3340
3341template <class _Tp>
3342struct is_trivially_assignable<_Tp&, _Tp>
3343    : integral_constant<bool, is_scalar<_Tp>::value> {};
3344
3345template <class _Tp>
3346struct is_trivially_assignable<_Tp&, _Tp&>
3347    : integral_constant<bool, is_scalar<_Tp>::value> {};
3348
3349template <class _Tp>
3350struct is_trivially_assignable<_Tp&, const _Tp&>
3351    : integral_constant<bool, is_scalar<_Tp>::value> {};
3352
3353template <class _Tp>
3354struct is_trivially_assignable<_Tp&, _Tp&&>
3355    : integral_constant<bool, is_scalar<_Tp>::value> {};
3356
3357#endif  // !__has_feature(is_trivially_assignable)
3358
3359#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3360template <class _Tp, class _Arg>
3361_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_assignable_v
3362    = is_trivially_assignable<_Tp, _Arg>::value;
3363#endif
3364
3365// is_trivially_copy_assignable
3366
3367template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3368    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3369                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3370
3371#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3372template <class _Tp>
3373_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_assignable_v
3374    = is_trivially_copy_assignable<_Tp>::value;
3375#endif
3376
3377// is_trivially_move_assignable
3378
3379template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3380    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3381                                     typename add_rvalue_reference<_Tp>::type>
3382    {};
3383
3384#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3385template <class _Tp>
3386_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_assignable_v
3387    = is_trivially_move_assignable<_Tp>::value;
3388#endif
3389
3390// is_trivially_destructible
3391
3392#if __has_keyword(__is_trivially_destructible)
3393
3394template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3395    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3396
3397#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3398
3399template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3400    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3401
3402#else
3403
3404template <class _Tp> struct __libcpp_trivial_destructor
3405    : public integral_constant<bool, is_scalar<_Tp>::value ||
3406                                     is_reference<_Tp>::value> {};
3407
3408template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3409    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3410
3411template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3412    : public false_type {};
3413
3414#endif
3415
3416#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3417template <class _Tp>
3418_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_destructible_v
3419    = is_trivially_destructible<_Tp>::value;
3420#endif
3421
3422// is_nothrow_constructible
3423
3424#if __has_keyword(__is_nothrow_constructible)
3425
3426template <class _Tp, class... _Args>
3427struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3428    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3429
3430#else
3431
3432template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3433
3434template <class _Tp, class... _Args>
3435struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3436    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3437{
3438};
3439
3440template <class _Tp>
3441void __implicit_conversion_to(_Tp) noexcept { }
3442
3443template <class _Tp, class _Arg>
3444struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3445    : public integral_constant<bool, noexcept(__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3446{
3447};
3448
3449template <class _Tp, bool _IsReference, class... _Args>
3450struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3451    : public false_type
3452{
3453};
3454
3455template <class _Tp, class... _Args>
3456struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3457    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3458{
3459};
3460
3461template <class _Tp, size_t _Ns>
3462struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3463    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3464{
3465};
3466
3467#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3468
3469
3470#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3471template <class _Tp, class ..._Args>
3472_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_constructible_v
3473    = is_nothrow_constructible<_Tp, _Args...>::value;
3474#endif
3475
3476// is_nothrow_default_constructible
3477
3478template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3479    : public is_nothrow_constructible<_Tp>
3480    {};
3481
3482#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3483template <class _Tp>
3484_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_default_constructible_v
3485    = is_nothrow_default_constructible<_Tp>::value;
3486#endif
3487
3488// is_nothrow_copy_constructible
3489
3490template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3491    : public is_nothrow_constructible<_Tp,
3492                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3493
3494#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3495template <class _Tp>
3496_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_constructible_v
3497    = is_nothrow_copy_constructible<_Tp>::value;
3498#endif
3499
3500// is_nothrow_move_constructible
3501
3502template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3503    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3504    {};
3505
3506#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3507template <class _Tp>
3508_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_constructible_v
3509    = is_nothrow_move_constructible<_Tp>::value;
3510#endif
3511
3512// is_nothrow_assignable
3513
3514#if __has_keyword(__is_nothrow_assignable)
3515
3516template <class _Tp, class _Arg>
3517struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3518    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3519
3520#else
3521
3522template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3523
3524template <class _Tp, class _Arg>
3525struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3526    : public false_type
3527{
3528};
3529
3530template <class _Tp, class _Arg>
3531struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3532    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>()) >
3533{
3534};
3535
3536template <class _Tp, class _Arg>
3537struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3538    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3539{
3540};
3541
3542#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3543
3544#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3545template <class _Tp, class _Arg>
3546_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_assignable_v
3547    = is_nothrow_assignable<_Tp, _Arg>::value;
3548#endif
3549
3550// is_nothrow_copy_assignable
3551
3552template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3553    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3554                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3555
3556#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3557template <class _Tp>
3558_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_assignable_v
3559    = is_nothrow_copy_assignable<_Tp>::value;
3560#endif
3561
3562// is_nothrow_move_assignable
3563
3564template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3565    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3566                                     typename add_rvalue_reference<_Tp>::type>
3567    {};
3568
3569#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3570template <class _Tp>
3571_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_assignable_v
3572    = is_nothrow_move_assignable<_Tp>::value;
3573#endif
3574
3575// is_nothrow_destructible
3576
3577#if !defined(_LIBCPP_CXX03_LANG)
3578
3579template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3580
3581template <class _Tp>
3582struct __libcpp_is_nothrow_destructible<false, _Tp>
3583    : public false_type
3584{
3585};
3586
3587template <class _Tp>
3588struct __libcpp_is_nothrow_destructible<true, _Tp>
3589    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>().~_Tp()) >
3590{
3591};
3592
3593template <class _Tp>
3594struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3595    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3596{
3597};
3598
3599template <class _Tp, size_t _Ns>
3600struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3601    : public is_nothrow_destructible<_Tp>
3602{
3603};
3604
3605template <class _Tp>
3606struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3607    : public true_type
3608{
3609};
3610
3611template <class _Tp>
3612struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3613    : public true_type
3614{
3615};
3616
3617#else
3618
3619template <class _Tp> struct __libcpp_nothrow_destructor
3620    : public integral_constant<bool, is_scalar<_Tp>::value ||
3621                                     is_reference<_Tp>::value> {};
3622
3623template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3624    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3625
3626template <class _Tp>
3627struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3628    : public false_type {};
3629
3630#endif
3631
3632#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3633template <class _Tp>
3634_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_destructible_v
3635    = is_nothrow_destructible<_Tp>::value;
3636#endif
3637
3638// is_pod
3639
3640#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3641
3642template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3643    : public integral_constant<bool, __is_pod(_Tp)> {};
3644
3645#else
3646
3647template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3648    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3649                                     is_trivially_copy_constructible<_Tp>::value      &&
3650                                     is_trivially_copy_assignable<_Tp>::value    &&
3651                                     is_trivially_destructible<_Tp>::value> {};
3652
3653#endif
3654
3655#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3656template <class _Tp>
3657_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pod_v
3658    = is_pod<_Tp>::value;
3659#endif
3660
3661// is_literal_type;
3662
3663template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_literal_type
3664    : public integral_constant<bool, __is_literal_type(_Tp)>
3665    {};
3666
3667#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3668template <class _Tp>
3669_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_literal_type_v
3670    = is_literal_type<_Tp>::value;
3671#endif
3672
3673// is_standard_layout;
3674
3675template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3676#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3677    : public integral_constant<bool, __is_standard_layout(_Tp)>
3678#else
3679    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3680#endif
3681    {};
3682
3683#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3684template <class _Tp>
3685_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_standard_layout_v
3686    = is_standard_layout<_Tp>::value;
3687#endif
3688
3689// is_trivially_copyable;
3690
3691template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3692#if __has_feature(is_trivially_copyable)
3693    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3694#elif _GNUC_VER >= 501
3695    : public integral_constant<bool, !is_volatile<_Tp>::value && __is_trivially_copyable(_Tp)>
3696#else
3697    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3698#endif
3699    {};
3700
3701#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3702template <class _Tp>
3703_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copyable_v
3704    = is_trivially_copyable<_Tp>::value;
3705#endif
3706
3707// is_trivial;
3708
3709template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3710#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3711    : public integral_constant<bool, __is_trivial(_Tp)>
3712#else
3713    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3714                                 is_trivially_default_constructible<_Tp>::value>
3715#endif
3716    {};
3717
3718#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3719template <class _Tp>
3720_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivial_v
3721    = is_trivial<_Tp>::value;
3722#endif
3723
3724template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3725template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3726template <class _Tp> struct __is_reference_wrapper
3727    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3728
3729#ifndef _LIBCPP_CXX03_LANG
3730
3731template <class _Fp, class _A0,
3732         class _DecayFp = typename decay<_Fp>::type,
3733         class _DecayA0 = typename decay<_A0>::type,
3734         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3735using __enable_if_bullet1 = typename enable_if
3736    <
3737        is_member_function_pointer<_DecayFp>::value
3738        && is_base_of<_ClassT, _DecayA0>::value
3739    >::type;
3740
3741template <class _Fp, class _A0,
3742         class _DecayFp = typename decay<_Fp>::type,
3743         class _DecayA0 = typename decay<_A0>::type>
3744using __enable_if_bullet2 = typename enable_if
3745    <
3746        is_member_function_pointer<_DecayFp>::value
3747        && __is_reference_wrapper<_DecayA0>::value
3748    >::type;
3749
3750template <class _Fp, class _A0,
3751         class _DecayFp = typename decay<_Fp>::type,
3752         class _DecayA0 = typename decay<_A0>::type,
3753         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3754using __enable_if_bullet3 = typename enable_if
3755    <
3756        is_member_function_pointer<_DecayFp>::value
3757        && !is_base_of<_ClassT, _DecayA0>::value
3758        && !__is_reference_wrapper<_DecayA0>::value
3759    >::type;
3760
3761template <class _Fp, class _A0,
3762         class _DecayFp = typename decay<_Fp>::type,
3763         class _DecayA0 = typename decay<_A0>::type,
3764         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3765using __enable_if_bullet4 = typename enable_if
3766    <
3767        is_member_object_pointer<_DecayFp>::value
3768        && is_base_of<_ClassT, _DecayA0>::value
3769    >::type;
3770
3771template <class _Fp, class _A0,
3772         class _DecayFp = typename decay<_Fp>::type,
3773         class _DecayA0 = typename decay<_A0>::type>
3774using __enable_if_bullet5 = typename enable_if
3775    <
3776        is_member_object_pointer<_DecayFp>::value
3777        && __is_reference_wrapper<_DecayA0>::value
3778    >::type;
3779
3780template <class _Fp, class _A0,
3781         class _DecayFp = typename decay<_Fp>::type,
3782         class _DecayA0 = typename decay<_A0>::type,
3783         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3784using __enable_if_bullet6 = typename enable_if
3785    <
3786        is_member_object_pointer<_DecayFp>::value
3787        && !is_base_of<_ClassT, _DecayA0>::value
3788        && !__is_reference_wrapper<_DecayA0>::value
3789    >::type;
3790
3791// __invoke forward declarations
3792
3793// fall back - none of the bullets
3794
3795#define _LIBCPP_INVOKE_RETURN(...) \
3796    noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) \
3797    { return __VA_ARGS__; }
3798
3799template <class ..._Args>
3800auto __invoke(__any, _Args&& ...__args) -> __nat;
3801
3802template <class ..._Args>
3803auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3804
3805// bullets 1, 2 and 3
3806
3807template <class _Fp, class _A0, class ..._Args,
3808          class = __enable_if_bullet1<_Fp, _A0>>
3809inline _LIBCPP_INLINE_VISIBILITY
3810auto
3811__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3812_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3813
3814template <class _Fp, class _A0, class ..._Args,
3815          class = __enable_if_bullet1<_Fp, _A0>>
3816inline _LIBCPP_INLINE_VISIBILITY
3817_LIBCPP_CONSTEXPR auto
3818__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3819_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3820
3821template <class _Fp, class _A0, class ..._Args,
3822          class = __enable_if_bullet2<_Fp, _A0>>
3823inline _LIBCPP_INLINE_VISIBILITY
3824auto
3825__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3826_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3827
3828template <class _Fp, class _A0, class ..._Args,
3829          class = __enable_if_bullet2<_Fp, _A0>>
3830inline _LIBCPP_INLINE_VISIBILITY
3831_LIBCPP_CONSTEXPR auto
3832__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3833_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3834
3835template <class _Fp, class _A0, class ..._Args,
3836          class = __enable_if_bullet3<_Fp, _A0>>
3837inline _LIBCPP_INLINE_VISIBILITY
3838auto
3839__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3840_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3841
3842template <class _Fp, class _A0, class ..._Args,
3843          class = __enable_if_bullet3<_Fp, _A0>>
3844inline _LIBCPP_INLINE_VISIBILITY
3845_LIBCPP_CONSTEXPR auto
3846__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3847_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3848
3849// bullets 4, 5 and 6
3850
3851template <class _Fp, class _A0,
3852          class = __enable_if_bullet4<_Fp, _A0>>
3853inline _LIBCPP_INLINE_VISIBILITY
3854auto
3855__invoke(_Fp&& __f, _A0&& __a0)
3856_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3857
3858template <class _Fp, class _A0,
3859          class = __enable_if_bullet4<_Fp, _A0>>
3860inline _LIBCPP_INLINE_VISIBILITY
3861_LIBCPP_CONSTEXPR auto
3862__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3863_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3864
3865template <class _Fp, class _A0,
3866          class = __enable_if_bullet5<_Fp, _A0>>
3867inline _LIBCPP_INLINE_VISIBILITY
3868auto
3869__invoke(_Fp&& __f, _A0&& __a0)
3870_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3871
3872template <class _Fp, class _A0,
3873          class = __enable_if_bullet5<_Fp, _A0>>
3874inline _LIBCPP_INLINE_VISIBILITY
3875_LIBCPP_CONSTEXPR auto
3876__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3877_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3878
3879template <class _Fp, class _A0,
3880          class = __enable_if_bullet6<_Fp, _A0>>
3881inline _LIBCPP_INLINE_VISIBILITY
3882auto
3883__invoke(_Fp&& __f, _A0&& __a0)
3884_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3885
3886template <class _Fp, class _A0,
3887          class = __enable_if_bullet6<_Fp, _A0>>
3888inline _LIBCPP_INLINE_VISIBILITY
3889_LIBCPP_CONSTEXPR auto
3890__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3891_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3892
3893// bullet 7
3894
3895template <class _Fp, class ..._Args>
3896inline _LIBCPP_INLINE_VISIBILITY
3897auto
3898__invoke(_Fp&& __f, _Args&& ...__args)
3899_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3900
3901template <class _Fp, class ..._Args>
3902inline _LIBCPP_INLINE_VISIBILITY
3903_LIBCPP_CONSTEXPR auto
3904__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3905_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3906
3907#undef _LIBCPP_INVOKE_RETURN
3908
3909// __invokable
3910template <class _Ret, class _Fp, class ..._Args>
3911struct __invokable_r
3912{
3913  template <class _XFp, class ..._XArgs>
3914  static auto __try_call(int) -> decltype(
3915    _VSTD::__invoke(_VSTD::declval<_XFp>(), _VSTD::declval<_XArgs>()...));
3916  template <class _XFp, class ..._XArgs>
3917  static __nat __try_call(...);
3918
3919  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3920  // or incomplete array types as required by the standard.
3921  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3922
3923  using type =
3924  typename conditional<
3925      _IsNotSame<_Result, __nat>::value,
3926      typename conditional<
3927          is_void<_Ret>::value,
3928          true_type,
3929          is_convertible<_Result, _Ret>
3930      >::type,
3931      false_type
3932  >::type;
3933  static const bool value = type::value;
3934};
3935template <class _Fp, class ..._Args>
3936using __invokable = __invokable_r<void, _Fp, _Args...>;
3937
3938template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3939struct __nothrow_invokable_r_imp {
3940  static const bool value = false;
3941};
3942
3943template <class _Ret, class _Fp, class ..._Args>
3944struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3945{
3946    typedef __nothrow_invokable_r_imp _ThisT;
3947
3948    template <class _Tp>
3949    static void __test_noexcept(_Tp) noexcept;
3950
3951    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3952        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...)));
3953};
3954
3955template <class _Ret, class _Fp, class ..._Args>
3956struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3957{
3958    static const bool value = noexcept(
3959        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...));
3960};
3961
3962template <class _Ret, class _Fp, class ..._Args>
3963using __nothrow_invokable_r =
3964    __nothrow_invokable_r_imp<
3965            __invokable_r<_Ret, _Fp, _Args...>::value,
3966            is_void<_Ret>::value,
3967            _Ret, _Fp, _Args...
3968    >;
3969
3970template <class _Fp, class ..._Args>
3971using __nothrow_invokable =
3972    __nothrow_invokable_r_imp<
3973            __invokable<_Fp, _Args...>::value,
3974            true, void, _Fp, _Args...
3975    >;
3976
3977template <class _Fp, class ..._Args>
3978struct __invoke_of
3979    : public enable_if<
3980        __invokable<_Fp, _Args...>::value,
3981        typename __invokable_r<void, _Fp, _Args...>::_Result>
3982{
3983};
3984
3985// result_of
3986
3987template <class _Fp, class ..._Args>
3988class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3989    : public __invoke_of<_Fp, _Args...>
3990{
3991};
3992
3993#if _LIBCPP_STD_VER > 11
3994template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
3995#endif
3996
3997#if _LIBCPP_STD_VER > 14
3998
3999// invoke_result
4000
4001template <class _Fn, class... _Args>
4002struct _LIBCPP_TEMPLATE_VIS invoke_result
4003    : __invoke_of<_Fn, _Args...>
4004{
4005};
4006
4007template <class _Fn, class... _Args>
4008using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
4009
4010// is_invocable
4011
4012template <class _Fn, class ..._Args>
4013struct _LIBCPP_TEMPLATE_VIS is_invocable
4014    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
4015
4016template <class _Ret, class _Fn, class ..._Args>
4017struct _LIBCPP_TEMPLATE_VIS is_invocable_r
4018    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
4019
4020template <class _Fn, class ..._Args>
4021_LIBCPP_INLINE_VAR constexpr bool is_invocable_v
4022    = is_invocable<_Fn, _Args...>::value;
4023
4024template <class _Ret, class _Fn, class ..._Args>
4025_LIBCPP_INLINE_VAR constexpr bool is_invocable_r_v
4026    = is_invocable_r<_Ret, _Fn, _Args...>::value;
4027
4028// is_nothrow_invocable
4029
4030template <class _Fn, class ..._Args>
4031struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
4032    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
4033
4034template <class _Ret, class _Fn, class ..._Args>
4035struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
4036    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
4037
4038template <class _Fn, class ..._Args>
4039_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_v
4040    = is_nothrow_invocable<_Fn, _Args...>::value;
4041
4042template <class _Ret, class _Fn, class ..._Args>
4043_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_r_v
4044    = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
4045
4046#endif // _LIBCPP_STD_VER > 14
4047
4048#endif  // !defined(_LIBCPP_CXX03_LANG)
4049
4050template <class _Tp> struct __is_swappable;
4051template <class _Tp> struct __is_nothrow_swappable;
4052
4053// swap, swap_ranges
4054
4055template <class _ForwardIterator1, class _ForwardIterator2>
4056inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4057_ForwardIterator2
4058swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2);
4059
4060template <class _Tp>
4061inline _LIBCPP_INLINE_VISIBILITY
4062#ifndef _LIBCPP_CXX03_LANG
4063typename enable_if
4064<
4065    is_move_constructible<_Tp>::value &&
4066    is_move_assignable<_Tp>::value
4067>::type
4068#else
4069void
4070#endif
4071_LIBCPP_CONSTEXPR_AFTER_CXX17
4072swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
4073                                    is_nothrow_move_assignable<_Tp>::value)
4074{
4075    _Tp __t(_VSTD::move(__x));
4076    __x = _VSTD::move(__y);
4077    __y = _VSTD::move(__t);
4078}
4079
4080template<class _Tp, size_t _Np>
4081inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4082typename enable_if<
4083    __is_swappable<_Tp>::value
4084>::type
4085swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
4086{
4087    _VSTD::swap_ranges(__a, __a + _Np, __b);
4088}
4089
4090template <class _ForwardIterator1, class _ForwardIterator2>
4091inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4092_ForwardIterator2
4093swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
4094{
4095    for(; __first1 != __last1; ++__first1, (void) ++__first2)
4096        swap(*__first1, *__first2);
4097    return __first2;
4098}
4099
4100// iter_swap
4101
4102template <class _ForwardIterator1, class _ForwardIterator2>
4103inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4104void
4105iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
4106    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
4107               _NOEXCEPT_(_NOEXCEPT_(swap(*_VSTD::declval<_ForwardIterator1>(),
4108                                          *_VSTD::declval<_ForwardIterator2>())))
4109{
4110    swap(*__a, *__b);
4111}
4112
4113// __swappable
4114
4115namespace __detail
4116{
4117// ALL generic swap overloads MUST already have a declaration available at this point.
4118
4119template <class _Tp, class _Up = _Tp,
4120          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
4121struct __swappable_with
4122{
4123    template <class _LHS, class _RHS>
4124    static decltype(swap(_VSTD::declval<_LHS>(), _VSTD::declval<_RHS>()))
4125    __test_swap(int);
4126    template <class, class>
4127    static __nat __test_swap(long);
4128
4129    // Extra parens are needed for the C++03 definition of decltype.
4130    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
4131    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
4132
4133    static const bool value = _IsNotSame<__swap1, __nat>::value
4134                           && _IsNotSame<__swap2, __nat>::value;
4135};
4136
4137template <class _Tp, class _Up>
4138struct __swappable_with<_Tp, _Up,  false> : false_type {};
4139
4140template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
4141struct __nothrow_swappable_with {
4142  static const bool value =
4143#ifndef _LIBCPP_HAS_NO_NOEXCEPT
4144      noexcept(swap(_VSTD::declval<_Tp>(), _VSTD::declval<_Up>()))
4145  &&  noexcept(swap(_VSTD::declval<_Up>(), _VSTD::declval<_Tp>()));
4146#else
4147      false;
4148#endif
4149};
4150
4151template <class _Tp, class _Up>
4152struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
4153
4154}  // __detail
4155
4156template <class _Tp>
4157struct __is_swappable
4158    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
4159{
4160};
4161
4162template <class _Tp>
4163struct __is_nothrow_swappable
4164    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
4165{
4166};
4167
4168#if _LIBCPP_STD_VER > 14
4169
4170template <class _Tp, class _Up>
4171struct _LIBCPP_TEMPLATE_VIS is_swappable_with
4172    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
4173{
4174};
4175
4176template <class _Tp>
4177struct _LIBCPP_TEMPLATE_VIS is_swappable
4178    : public conditional<
4179        __is_referenceable<_Tp>::value,
4180        is_swappable_with<
4181            typename add_lvalue_reference<_Tp>::type,
4182            typename add_lvalue_reference<_Tp>::type>,
4183        false_type
4184    >::type
4185{
4186};
4187
4188template <class _Tp, class _Up>
4189struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
4190    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
4191{
4192};
4193
4194template <class _Tp>
4195struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
4196    : public conditional<
4197        __is_referenceable<_Tp>::value,
4198        is_nothrow_swappable_with<
4199            typename add_lvalue_reference<_Tp>::type,
4200            typename add_lvalue_reference<_Tp>::type>,
4201        false_type
4202    >::type
4203{
4204};
4205
4206template <class _Tp, class _Up>
4207_LIBCPP_INLINE_VAR constexpr bool is_swappable_with_v
4208    = is_swappable_with<_Tp, _Up>::value;
4209
4210template <class _Tp>
4211_LIBCPP_INLINE_VAR constexpr bool is_swappable_v
4212    = is_swappable<_Tp>::value;
4213
4214template <class _Tp, class _Up>
4215_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_with_v
4216    = is_nothrow_swappable_with<_Tp, _Up>::value;
4217
4218template <class _Tp>
4219_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_v
4220    = is_nothrow_swappable<_Tp>::value;
4221
4222#endif // _LIBCPP_STD_VER > 14
4223
4224template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4225
4226template <class _Tp>
4227struct __underlying_type_impl<_Tp, false> {};
4228
4229template <class _Tp>
4230struct __underlying_type_impl<_Tp, true>
4231{
4232    typedef __underlying_type(_Tp) type;
4233};
4234
4235template <class _Tp>
4236struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4237
4238#if _LIBCPP_STD_VER > 11
4239template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4240#endif
4241
4242template <class _Tp, bool = is_enum<_Tp>::value>
4243struct __sfinae_underlying_type
4244{
4245    typedef typename underlying_type<_Tp>::type type;
4246    typedef decltype(((type)1) + 0) __promoted_type;
4247};
4248
4249template <class _Tp>
4250struct __sfinae_underlying_type<_Tp, false> {};
4251
4252inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4253int __convert_to_integral(int __val) { return __val; }
4254
4255inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4256unsigned __convert_to_integral(unsigned __val) { return __val; }
4257
4258inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4259long __convert_to_integral(long __val) { return __val; }
4260
4261inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4262unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4263
4264inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4265long long __convert_to_integral(long long __val) { return __val; }
4266
4267inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4268unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4269
4270template<typename _Fp>
4271inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4272typename enable_if<is_floating_point<_Fp>::value, long long>::type
4273 __convert_to_integral(_Fp __val) { return __val; }
4274
4275#ifndef _LIBCPP_HAS_NO_INT128
4276inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4277__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4278
4279inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4280__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4281#endif
4282
4283template <class _Tp>
4284inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4285typename __sfinae_underlying_type<_Tp>::__promoted_type
4286__convert_to_integral(_Tp __val) { return __val; }
4287
4288#ifndef _LIBCPP_CXX03_LANG
4289
4290template <class _Tp>
4291struct __has_operator_addressof_member_imp
4292{
4293    template <class _Up>
4294        static auto __test(int)
4295            -> typename __select_2nd<decltype(_VSTD::declval<_Up>().operator&()), true_type>::type;
4296    template <class>
4297        static auto __test(long) -> false_type;
4298
4299    static const bool value = decltype(__test<_Tp>(0))::value;
4300};
4301
4302template <class _Tp>
4303struct __has_operator_addressof_free_imp
4304{
4305    template <class _Up>
4306        static auto __test(int)
4307            -> typename __select_2nd<decltype(operator&(_VSTD::declval<_Up>())), true_type>::type;
4308    template <class>
4309        static auto __test(long) -> false_type;
4310
4311    static const bool value = decltype(__test<_Tp>(0))::value;
4312};
4313
4314template <class _Tp>
4315struct __has_operator_addressof
4316    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
4317                                  || __has_operator_addressof_free_imp<_Tp>::value>
4318{};
4319
4320#endif  // _LIBCPP_CXX03_LANG
4321
4322#if _LIBCPP_STD_VER > 14
4323
4324template <class... _Args>
4325struct conjunction : _And<_Args...> {};
4326template<class... _Args>
4327_LIBCPP_INLINE_VAR constexpr bool conjunction_v
4328    = conjunction<_Args...>::value;
4329
4330template <class... _Args>
4331struct disjunction : _Or<_Args...> {};
4332template<class... _Args>
4333_LIBCPP_INLINE_VAR constexpr bool disjunction_v
4334    = disjunction<_Args...>::value;
4335
4336template <class _Tp>
4337struct negation : _Not<_Tp> {};
4338template<class _Tp>
4339_LIBCPP_INLINE_VAR constexpr bool negation_v
4340    = negation<_Tp>::value;
4341#endif  // _LIBCPP_STD_VER > 14
4342
4343// These traits are used in __tree and __hash_table
4344#ifndef _LIBCPP_CXX03_LANG
4345struct __extract_key_fail_tag {};
4346struct __extract_key_self_tag {};
4347struct __extract_key_first_tag {};
4348
4349template <class _ValTy, class _Key,
4350          class _RawValTy = typename __unconstref<_ValTy>::type>
4351struct __can_extract_key
4352    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4353                  __extract_key_fail_tag>::type {};
4354
4355template <class _Pair, class _Key, class _First, class _Second>
4356struct __can_extract_key<_Pair, _Key, pair<_First, _Second>>
4357    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4358                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4359
4360// __can_extract_map_key uses true_type/false_type instead of the tags.
4361// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4362// and _ValTy == _Key.
4363template <class _ValTy, class _Key, class _ContainerValueTy,
4364          class _RawValTy = typename __unconstref<_ValTy>::type>
4365struct __can_extract_map_key
4366    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4367
4368// This specialization returns __extract_key_fail_tag for non-map containers
4369// because _Key == _ContainerValueTy
4370template <class _ValTy, class _Key, class _RawValTy>
4371struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4372    : false_type {};
4373
4374#endif
4375
4376#ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
4377#if _LIBCPP_STD_VER > 17
4378_LIBCPP_INLINE_VISIBILITY
4379inline constexpr bool is_constant_evaluated() noexcept {
4380  return __builtin_is_constant_evaluated();
4381}
4382#endif
4383
4384inline _LIBCPP_CONSTEXPR
4385bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4386#else
4387inline _LIBCPP_CONSTEXPR
4388bool __libcpp_is_constant_evaluated() _NOEXCEPT { return false; }
4389#endif
4390
4391template <class _CharT>
4392using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4393
4394_LIBCPP_END_NAMESPACE_STD
4395
4396#if _LIBCPP_STD_VER > 14
4397// std::byte
4398namespace std  // purposefully not versioned
4399{
4400
4401
4402}
4403#endif
4404
4405#endif  // _LIBCPP_TYPE_TRAITS
4406