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
900template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
901template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
902
903template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
904#if defined(_LIBCPP_HAS_OBJC_ARC)
905template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
906template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
907template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
908template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
909#endif
910
911template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
912    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
913
914#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
915template <class _Tp>
916_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v
917    = is_pointer<_Tp>::value;
918#endif
919
920// is_reference
921
922#if __has_keyword(__is_lvalue_reference) && \
923    __has_keyword(__is_rvalue_reference) && \
924    __has_keyword(__is_reference)
925
926template<class _Tp>
927struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
928
929template<class _Tp>
930struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
931
932template<class _Tp>
933struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
934
935#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
936template <class _Tp>
937_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v = __is_reference(_Tp);
938
939template <class _Tp>
940_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
941
942template <class _Tp>
943_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
944#endif
945
946#else // __has_keyword(__is_lvalue_reference) && etc...
947
948template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
949template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
950
951template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
952template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
953
954template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
955template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
956template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
957
958#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
959template <class _Tp>
960_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v
961    = is_reference<_Tp>::value;
962
963template <class _Tp>
964_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v
965    = is_lvalue_reference<_Tp>::value;
966
967template <class _Tp>
968_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v
969    = is_rvalue_reference<_Tp>::value;
970#endif
971
972#endif // __has_keyword(__is_lvalue_reference) && etc...
973
974// is_union
975
976#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
977
978template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
979    : public integral_constant<bool, __is_union(_Tp)> {};
980
981#else
982
983template <class _Tp> struct __libcpp_union : public false_type {};
984template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
985    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
986
987#endif
988
989#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
990template <class _Tp>
991_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_union_v
992    = is_union<_Tp>::value;
993#endif
994
995// is_class
996
997#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
998
999template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
1000    : public integral_constant<bool, __is_class(_Tp)> {};
1001
1002#else
1003
1004namespace __is_class_imp
1005{
1006template <class _Tp> char  __test(int _Tp::*);
1007template <class _Tp> __two __test(...);
1008}
1009
1010template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
1011    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
1012
1013#endif
1014
1015#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1016template <class _Tp>
1017_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_class_v
1018    = is_class<_Tp>::value;
1019#endif
1020
1021// is_function
1022
1023template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
1024    : public _BoolConstant<
1025#ifdef __clang__
1026    __is_function(_Tp)
1027#else
1028 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
1029#endif
1030    > {};
1031
1032
1033#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1034template <class _Tp>
1035_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_function_v
1036    = is_function<_Tp>::value;
1037#endif
1038
1039template <class _Tp> struct __libcpp_is_member_pointer {
1040  enum {
1041    __is_member = false,
1042    __is_func = false,
1043    __is_obj = false
1044  };
1045};
1046template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
1047  enum {
1048    __is_member = true,
1049    __is_func = is_function<_Tp>::value,
1050    __is_obj = !__is_func,
1051  };
1052};
1053
1054#if __has_keyword(__is_member_function_pointer)
1055
1056template<class _Tp>
1057struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1058    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1059
1060#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1061template <class _Tp>
1062_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1063    = __is_member_function_pointer(_Tp);
1064#endif
1065
1066#else // __has_keyword(__is_member_function_pointer)
1067
1068template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1069    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1070
1071#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1072template <class _Tp>
1073_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1074    = is_member_function_pointer<_Tp>::value;
1075#endif
1076
1077#endif // __has_keyword(__is_member_function_pointer)
1078
1079// is_member_pointer
1080
1081#if __has_keyword(__is_member_pointer)
1082
1083template<class _Tp>
1084struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
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_pointer_v = __is_member_pointer(_Tp);
1089#endif
1090
1091#else // __has_keyword(__is_member_pointer)
1092
1093template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1094 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1095
1096#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1097template <class _Tp>
1098_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v
1099    = is_member_pointer<_Tp>::value;
1100#endif
1101
1102#endif // __has_keyword(__is_member_pointer)
1103
1104// is_member_object_pointer
1105
1106#if __has_keyword(__is_member_object_pointer)
1107
1108template<class _Tp>
1109struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1110    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1111
1112#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1113template <class _Tp>
1114_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1115    = __is_member_object_pointer(_Tp);
1116#endif
1117
1118#else // __has_keyword(__is_member_object_pointer)
1119
1120template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1121    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1122
1123#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1124template <class _Tp>
1125_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1126    = is_member_object_pointer<_Tp>::value;
1127#endif
1128
1129#endif // __has_keyword(__is_member_object_pointer)
1130
1131// is_enum
1132
1133#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1134
1135template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1136    : public integral_constant<bool, __is_enum(_Tp)> {};
1137
1138#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1139template <class _Tp>
1140_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v = __is_enum(_Tp);
1141#endif
1142
1143#else
1144
1145template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1146    : public integral_constant<bool, !is_void<_Tp>::value             &&
1147                                     !is_integral<_Tp>::value         &&
1148                                     !is_floating_point<_Tp>::value   &&
1149                                     !is_array<_Tp>::value            &&
1150                                     !is_pointer<_Tp>::value          &&
1151                                     !is_reference<_Tp>::value        &&
1152                                     !is_member_pointer<_Tp>::value   &&
1153                                     !is_union<_Tp>::value            &&
1154                                     !is_class<_Tp>::value            &&
1155                                     !is_function<_Tp>::value         > {};
1156
1157#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1158template <class _Tp>
1159_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v
1160    = is_enum<_Tp>::value;
1161#endif
1162
1163#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1164
1165// is_arithmetic
1166
1167
1168template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1169    : public integral_constant<bool, is_integral<_Tp>::value      ||
1170                                     is_floating_point<_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_arithmetic_v
1175    = is_arithmetic<_Tp>::value;
1176#endif
1177
1178// is_fundamental
1179
1180// In clang 9 and lower, this builtin did not work for nullptr_t. Additionally, in C++03 mode,
1181// nullptr isn't defined by the compiler so, this builtin won't work.
1182#if __has_keyword(__is_fundamental) && _LIBCPP_CLANG_VER > 900 && !defined(_LIBCPP_CXX03_LANG)
1183
1184template<class _Tp>
1185struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1186
1187#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1188template <class _Tp>
1189_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v = __is_fundamental(_Tp);
1190#endif
1191
1192#else // __has_keyword(__is_fundamental)
1193
1194template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1195    : public integral_constant<bool, is_void<_Tp>::value        ||
1196                                     __is_nullptr_t<_Tp>::value ||
1197                                     is_arithmetic<_Tp>::value> {};
1198
1199#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1200template <class _Tp>
1201_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v
1202    = is_fundamental<_Tp>::value;
1203#endif
1204
1205#endif // __has_keyword(__is_fundamental)
1206
1207// is_scalar
1208
1209// >= 11 because in C++03 nullptr isn't actually nullptr
1210#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1211
1212template<class _Tp>
1213struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1214
1215#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1216template <class _Tp>
1217_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v = __is_scalar(_Tp);
1218#endif
1219
1220#else // __has_keyword(__is_scalar)
1221
1222template <class _Tp> struct __is_block : false_type {};
1223#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1224template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1225#endif
1226
1227template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1228    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1229                                     is_member_pointer<_Tp>::value ||
1230                                     is_pointer<_Tp>::value        ||
1231                                     __is_nullptr_t<_Tp>::value    ||
1232                                     __is_block<_Tp>::value        ||
1233                                     is_enum<_Tp>::value           > {};
1234
1235template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1236
1237#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1238template <class _Tp>
1239_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v
1240    = is_scalar<_Tp>::value;
1241#endif
1242
1243#endif // __has_keyword(__is_scalar)
1244
1245// is_object
1246
1247#if __has_keyword(__is_object)
1248
1249template<class _Tp>
1250struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1251
1252#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1253template <class _Tp>
1254_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v = __is_object(_Tp);
1255#endif
1256
1257#else // __has_keyword(__is_object)
1258
1259template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1260    : public integral_constant<bool, is_scalar<_Tp>::value ||
1261                                     is_array<_Tp>::value  ||
1262                                     is_union<_Tp>::value  ||
1263                                     is_class<_Tp>::value  > {};
1264
1265#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1266template <class _Tp>
1267_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v
1268    = is_object<_Tp>::value;
1269#endif
1270
1271#endif // __has_keyword(__is_object)
1272
1273// is_compound
1274
1275// >= 11 because in C++03 nullptr isn't actually nullptr
1276#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1277
1278template<class _Tp>
1279struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1280
1281#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1282template <class _Tp>
1283_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v = __is_compound(_Tp);
1284#endif
1285
1286#else // __has_keyword(__is_compound)
1287
1288template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1289    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1290
1291#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1292template <class _Tp>
1293_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v
1294    = is_compound<_Tp>::value;
1295#endif
1296
1297#endif // __has_keyword(__is_compound)
1298
1299// __is_referenceable  [defns.referenceable]
1300
1301struct __is_referenceable_impl {
1302    template <class _Tp> static _Tp& __test(int);
1303    template <class _Tp> static __two __test(...);
1304};
1305
1306template <class _Tp>
1307struct __is_referenceable : integral_constant<bool,
1308    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1309
1310
1311// add_const
1312
1313template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1314  typedef _LIBCPP_NODEBUG_TYPE const _Tp type;
1315};
1316
1317#if _LIBCPP_STD_VER > 11
1318template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1319#endif
1320
1321// add_volatile
1322
1323template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1324  typedef _LIBCPP_NODEBUG_TYPE volatile _Tp type;
1325};
1326
1327#if _LIBCPP_STD_VER > 11
1328template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1329#endif
1330
1331// add_cv
1332template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1333  typedef _LIBCPP_NODEBUG_TYPE const volatile _Tp type;
1334};
1335
1336#if _LIBCPP_STD_VER > 11
1337template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1338#endif
1339
1340// remove_reference
1341
1342#if __has_keyword(__remove_reference)
1343
1344template<class _Tp>
1345struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1346
1347#else // __has_keyword(__remove_reference)
1348
1349template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1350template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1351template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1352
1353#if _LIBCPP_STD_VER > 11
1354template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1355#endif
1356
1357#endif // __has_keyword(__remove_reference)
1358
1359// add_lvalue_reference
1360
1361template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE _Tp  type; };
1362template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
1363
1364template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1365{typedef _LIBCPP_NODEBUG_TYPE typename  __add_lvalue_reference_impl<_Tp>::type type;};
1366
1367#if _LIBCPP_STD_VER > 11
1368template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1369#endif
1370
1371template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE  _Tp   type; };
1372template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE  _Tp&& type; };
1373
1374template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1375{typedef _LIBCPP_NODEBUG_TYPE  typename __add_rvalue_reference_impl<_Tp>::type type;};
1376
1377#if _LIBCPP_STD_VER > 11
1378template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1379#endif
1380
1381// Suppress deprecation notice for volatile-qualified return type resulting
1382// from volatile-qualified types _Tp.
1383_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1384template <class _Tp> _Tp&& __declval(int);
1385template <class _Tp> _Tp   __declval(long);
1386_LIBCPP_SUPPRESS_DEPRECATED_POP
1387
1388template <class _Tp>
1389decltype(_VSTD::__declval<_Tp>(0))
1390declval() _NOEXCEPT;
1391
1392// __uncvref
1393
1394template <class _Tp>
1395struct __uncvref  {
1396    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1397};
1398
1399template <class _Tp>
1400struct __unconstref {
1401    typedef _LIBCPP_NODEBUG_TYPE typename remove_const<typename remove_reference<_Tp>::type>::type type;
1402};
1403
1404#ifndef _LIBCPP_CXX03_LANG
1405template <class _Tp>
1406using __uncvref_t _LIBCPP_NODEBUG_TYPE = typename __uncvref<_Tp>::type;
1407#endif
1408
1409// __is_same_uncvref
1410
1411template <class _Tp, class _Up>
1412struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1413                                   typename __uncvref<_Up>::type> {};
1414
1415#if _LIBCPP_STD_VER > 17
1416// remove_cvref - same as __uncvref
1417template <class _Tp>
1418struct remove_cvref : public __uncvref<_Tp> {};
1419
1420template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1421#endif
1422
1423
1424struct __any
1425{
1426    __any(...);
1427};
1428
1429// remove_pointer
1430
1431template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1432template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1433template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1434template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1435template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1436
1437#if _LIBCPP_STD_VER > 11
1438template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1439#endif
1440
1441// add_pointer
1442
1443template <class _Tp,
1444        bool = __is_referenceable<_Tp>::value ||
1445                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1446struct __add_pointer_impl
1447    {typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type* type;};
1448template <class _Tp> struct __add_pointer_impl<_Tp, false>
1449    {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1450
1451template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1452    {typedef _LIBCPP_NODEBUG_TYPE typename __add_pointer_impl<_Tp>::type type;};
1453
1454#if _LIBCPP_STD_VER > 11
1455template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1456#endif
1457
1458// type_identity
1459#if _LIBCPP_STD_VER > 17
1460template<class _Tp> struct type_identity { typedef _Tp type; };
1461template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1462#endif
1463
1464// is_signed
1465
1466// In clang 9 and earlier, this builtin did not work for floating points or enums
1467#if __has_keyword(__is_signed) && _LIBCPP_CLANG_VER > 900
1468
1469template<class _Tp>
1470struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1471
1472#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1473template <class _Tp>
1474_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v = __is_signed(_Tp);
1475#endif
1476
1477#else // __has_keyword(__is_signed)
1478
1479template <class _Tp, bool = is_integral<_Tp>::value>
1480struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1481
1482template <class _Tp>
1483struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1484
1485template <class _Tp, bool = is_arithmetic<_Tp>::value>
1486struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1487
1488template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1489
1490template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1491
1492#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1493template <class _Tp>
1494_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v
1495    = is_signed<_Tp>::value;
1496#endif
1497
1498#endif // __has_keyword(__is_signed)
1499
1500// is_unsigned
1501
1502#if __has_keyword(__is_unsigned)
1503
1504template<class _Tp>
1505struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_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_unsigned_v = __is_unsigned(_Tp);
1510#endif
1511
1512#else // __has_keyword(__is_unsigned)
1513
1514template <class _Tp, bool = is_integral<_Tp>::value>
1515struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1516
1517template <class _Tp>
1518struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1519
1520template <class _Tp, bool = is_arithmetic<_Tp>::value>
1521struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1522
1523template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1524
1525template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1526
1527#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1528template <class _Tp>
1529_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v
1530    = is_unsigned<_Tp>::value;
1531#endif
1532
1533#endif // __has_keyword(__is_unsigned)
1534
1535// rank
1536
1537template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1538    : public integral_constant<size_t, 0> {};
1539template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1540    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1541template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1542    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1543
1544#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1545template <class _Tp>
1546_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t rank_v
1547    = rank<_Tp>::value;
1548#endif
1549
1550// extent
1551
1552#if __has_keyword(__array_extent)
1553
1554template<class _Tp, size_t _Dim = 0>
1555struct _LIBCPP_TEMPLATE_VIS extent
1556    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1557
1558#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1559template <class _Tp, unsigned _Ip = 0>
1560_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v = __array_extent(_Tp, _Ip);
1561#endif
1562
1563#else // __has_keyword(__array_extent)
1564
1565template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1566    : public integral_constant<size_t, 0> {};
1567template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1568    : public integral_constant<size_t, 0> {};
1569template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1570    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1571template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1572    : public integral_constant<size_t, _Np> {};
1573template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1574    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1575
1576#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1577template <class _Tp, unsigned _Ip = 0>
1578_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v
1579    = extent<_Tp, _Ip>::value;
1580#endif
1581
1582#endif // __has_keyword(__array_extent)
1583
1584// remove_extent
1585
1586template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1587    {typedef _Tp type;};
1588template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1589    {typedef _Tp type;};
1590template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1591    {typedef _Tp type;};
1592
1593#if _LIBCPP_STD_VER > 11
1594template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1595#endif
1596
1597// remove_all_extents
1598
1599template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1600    {typedef _Tp type;};
1601template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1602    {typedef typename remove_all_extents<_Tp>::type type;};
1603template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1604    {typedef typename remove_all_extents<_Tp>::type type;};
1605
1606#if _LIBCPP_STD_VER > 11
1607template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1608#endif
1609
1610#if _LIBCPP_STD_VER > 17
1611// is_bounded_array
1612
1613template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1614template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1615
1616template <class _Tp>
1617_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1618bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1619
1620// is_unbounded_array
1621
1622template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1623template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1624
1625template <class _Tp>
1626_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1627bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1628#endif
1629
1630// decay
1631
1632template <class _Up, bool>
1633struct __decay {
1634    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<_Up>::type type;
1635};
1636
1637template <class _Up>
1638struct __decay<_Up, true> {
1639public:
1640    typedef _LIBCPP_NODEBUG_TYPE typename conditional
1641                     <
1642                         is_array<_Up>::value,
1643                         typename remove_extent<_Up>::type*,
1644                         typename conditional
1645                         <
1646                              is_function<_Up>::value,
1647                              typename add_pointer<_Up>::type,
1648                              typename remove_cv<_Up>::type
1649                         >::type
1650                     >::type type;
1651};
1652
1653template <class _Tp>
1654struct _LIBCPP_TEMPLATE_VIS decay
1655{
1656private:
1657    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
1658public:
1659    typedef _LIBCPP_NODEBUG_TYPE typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1660};
1661
1662#if _LIBCPP_STD_VER > 11
1663template <class _Tp> using decay_t = typename decay<_Tp>::type;
1664#endif
1665
1666// is_abstract
1667
1668template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1669    : public integral_constant<bool, __is_abstract(_Tp)> {};
1670
1671#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1672template <class _Tp>
1673_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_abstract_v
1674    = is_abstract<_Tp>::value;
1675#endif
1676
1677// is_final
1678
1679template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1680__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1681
1682#if _LIBCPP_STD_VER > 11
1683template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1684is_final : public integral_constant<bool, __is_final(_Tp)> {};
1685#endif
1686
1687#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1688template <class _Tp>
1689_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_final_v
1690    = is_final<_Tp>::value;
1691#endif
1692
1693// is_aggregate
1694#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1695
1696template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1697is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1698
1699#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1700template <class _Tp>
1701_LIBCPP_INLINE_VAR constexpr bool is_aggregate_v
1702    = is_aggregate<_Tp>::value;
1703#endif
1704
1705#endif // _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1706
1707// is_base_of
1708
1709template <class _Bp, class _Dp>
1710struct _LIBCPP_TEMPLATE_VIS is_base_of
1711    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1712
1713#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1714template <class _Bp, class _Dp>
1715_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_base_of_v
1716    = is_base_of<_Bp, _Dp>::value;
1717#endif
1718
1719// is_convertible
1720
1721#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1722
1723template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1724    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1725
1726#else  // __has_feature(is_convertible_to)
1727
1728namespace __is_convertible_imp
1729{
1730template <class _Tp> void  __test_convert(_Tp);
1731
1732template <class _From, class _To, class = void>
1733struct __is_convertible_test : public false_type {};
1734
1735template <class _From, class _To>
1736struct __is_convertible_test<_From, _To,
1737    decltype(_VSTD::__is_convertible_imp::__test_convert<_To>(_VSTD::declval<_From>()))> : public true_type
1738{};
1739
1740template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1741                     bool _IsFunction = is_function<_Tp>::value,
1742                     bool _IsVoid =     is_void<_Tp>::value>
1743                     struct __is_array_function_or_void                          {enum {value = 0};};
1744template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1745template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1746template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1747}
1748
1749template <class _Tp,
1750    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1751struct __is_convertible_check
1752{
1753    static const size_t __v = 0;
1754};
1755
1756template <class _Tp>
1757struct __is_convertible_check<_Tp, 0>
1758{
1759    static const size_t __v = sizeof(_Tp);
1760};
1761
1762template <class _T1, class _T2,
1763    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1764    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1765struct __is_convertible
1766    : public integral_constant<bool,
1767        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1768    >
1769{};
1770
1771template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1772template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1773template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1774template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1775
1776template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1777template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1778template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1779template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1780
1781template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1782template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1783template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1784template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1785
1786template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1787    : public __is_convertible<_T1, _T2>
1788{
1789    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1790    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1791};
1792
1793#endif  // __has_feature(is_convertible_to)
1794
1795#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1796template <class _From, class _To>
1797_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_convertible_v
1798    = is_convertible<_From, _To>::value;
1799#endif
1800
1801// is_nothrow_convertible
1802
1803#if _LIBCPP_STD_VER > 17
1804
1805template <typename _Tp>
1806static void __test_noexcept(_Tp) noexcept;
1807
1808template<typename _Fm, typename _To>
1809static bool_constant<noexcept(__test_noexcept<_To>(declval<_Fm>()))>
1810__is_nothrow_convertible_test();
1811
1812template <typename _Fm, typename _To>
1813struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1814{ };
1815
1816template <typename _Fm, typename _To>
1817struct is_nothrow_convertible : _Or<
1818    _And<is_void<_To>, is_void<_Fm>>,
1819    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1820>::type { };
1821
1822template <typename _Fm, typename _To>
1823inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1824
1825#endif // _LIBCPP_STD_VER > 17
1826
1827// is_empty
1828
1829#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1830
1831template <class _Tp>
1832struct _LIBCPP_TEMPLATE_VIS is_empty
1833    : public integral_constant<bool, __is_empty(_Tp)> {};
1834
1835#else  // __has_feature(is_empty)
1836
1837template <class _Tp>
1838struct __is_empty1
1839    : public _Tp
1840{
1841    double __lx;
1842};
1843
1844struct __is_empty2
1845{
1846    double __lx;
1847};
1848
1849template <class _Tp, bool = is_class<_Tp>::value>
1850struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1851
1852template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1853
1854template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1855
1856#endif  // __has_feature(is_empty)
1857
1858#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1859template <class _Tp>
1860_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_empty_v
1861    = is_empty<_Tp>::value;
1862#endif
1863
1864// is_polymorphic
1865
1866#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1867
1868template <class _Tp>
1869struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1870    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1871
1872#else
1873
1874template<typename _Tp> char &__is_polymorphic_impl(
1875    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1876                       int>::type);
1877template<typename _Tp> __two &__is_polymorphic_impl(...);
1878
1879template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1880    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1881
1882#endif // __has_feature(is_polymorphic)
1883
1884#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1885template <class _Tp>
1886_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_polymorphic_v
1887    = is_polymorphic<_Tp>::value;
1888#endif
1889
1890// has_virtual_destructor
1891
1892#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1893
1894template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1895    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1896
1897#else
1898
1899template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1900    : public false_type {};
1901
1902#endif
1903
1904#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1905template <class _Tp>
1906_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_virtual_destructor_v
1907    = has_virtual_destructor<_Tp>::value;
1908#endif
1909
1910// has_unique_object_representations
1911
1912#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_UNIQUE_OBJECT_REPRESENTATIONS)
1913
1914template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1915    : public integral_constant<bool,
1916       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1917
1918#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1919template <class _Tp>
1920_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_unique_object_representations_v
1921    = has_unique_object_representations<_Tp>::value;
1922#endif
1923
1924#endif
1925
1926// alignment_of
1927
1928template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1929    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1930
1931#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1932template <class _Tp>
1933_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t alignment_of_v
1934    = alignment_of<_Tp>::value;
1935#endif
1936
1937// aligned_storage
1938
1939template <class _Hp, class _Tp>
1940struct __type_list
1941{
1942    typedef _Hp _Head;
1943    typedef _Tp _Tail;
1944};
1945
1946struct __nat
1947{
1948#ifndef _LIBCPP_CXX03_LANG
1949    __nat() = delete;
1950    __nat(const __nat&) = delete;
1951    __nat& operator=(const __nat&) = delete;
1952    ~__nat() = delete;
1953#endif
1954};
1955
1956template <class _Tp>
1957struct __align_type
1958{
1959    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1960    typedef _Tp type;
1961};
1962
1963struct __struct_double {long double __lx;};
1964struct __struct_double4 {double __lx[4];};
1965
1966typedef
1967    __type_list<__align_type<unsigned char>,
1968    __type_list<__align_type<unsigned short>,
1969    __type_list<__align_type<unsigned int>,
1970    __type_list<__align_type<unsigned long>,
1971    __type_list<__align_type<unsigned long long>,
1972    __type_list<__align_type<double>,
1973    __type_list<__align_type<long double>,
1974    __type_list<__align_type<__struct_double>,
1975    __type_list<__align_type<__struct_double4>,
1976    __type_list<__align_type<int*>,
1977    __nat
1978    > > > > > > > > > > __all_types;
1979
1980template <size_t _Align>
1981struct _ALIGNAS(_Align) __fallback_overaligned {};
1982
1983template <class _TL, size_t _Align> struct __find_pod;
1984
1985template <class _Hp, size_t _Align>
1986struct __find_pod<__type_list<_Hp, __nat>, _Align>
1987{
1988    typedef typename conditional<
1989                             _Align == _Hp::value,
1990                             typename _Hp::type,
1991                             __fallback_overaligned<_Align>
1992                         >::type type;
1993};
1994
1995template <class _Hp, class _Tp, size_t _Align>
1996struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1997{
1998    typedef typename conditional<
1999                             _Align == _Hp::value,
2000                             typename _Hp::type,
2001                             typename __find_pod<_Tp, _Align>::type
2002                         >::type type;
2003};
2004
2005template <class _TL, size_t _Len> struct __find_max_align;
2006
2007template <class _Hp, size_t _Len>
2008struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
2009
2010template <size_t _Len, size_t _A1, size_t _A2>
2011struct __select_align
2012{
2013private:
2014    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
2015    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
2016public:
2017    static const size_t value = _Len < __max ? __min : __max;
2018};
2019
2020template <class _Hp, class _Tp, size_t _Len>
2021struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
2022    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
2023
2024template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2025struct _LIBCPP_TEMPLATE_VIS aligned_storage
2026{
2027    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
2028    union type
2029    {
2030        _Aligner __align;
2031        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
2032    };
2033};
2034
2035#if _LIBCPP_STD_VER > 11
2036template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
2037    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
2038#endif
2039
2040#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
2041template <size_t _Len>\
2042struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
2043{\
2044    struct _ALIGNAS(n) type\
2045    {\
2046        unsigned char __lx[(_Len + n - 1)/n * n];\
2047    };\
2048}
2049
2050_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2051_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2052_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2053_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2054_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2055_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2056_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2057_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2058_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2059_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2060_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2061_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2062_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2063_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2064// PE/COFF does not support alignment beyond 8192 (=0x2000)
2065#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2066_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2067#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2068
2069#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2070
2071
2072// aligned_union
2073
2074template <size_t _I0, size_t ..._In>
2075struct __static_max;
2076
2077template <size_t _I0>
2078struct __static_max<_I0>
2079{
2080    static const size_t value = _I0;
2081};
2082
2083template <size_t _I0, size_t _I1, size_t ..._In>
2084struct __static_max<_I0, _I1, _In...>
2085{
2086    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2087                                             __static_max<_I1, _In...>::value;
2088};
2089
2090template <size_t _Len, class _Type0, class ..._Types>
2091struct aligned_union
2092{
2093    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2094                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2095    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2096                                             sizeof(_Types)...>::value;
2097    typedef typename aligned_storage<__len, alignment_value>::type type;
2098};
2099
2100#if _LIBCPP_STD_VER > 11
2101template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2102#endif
2103
2104template <class _Tp>
2105struct __numeric_type
2106{
2107   static void __test(...);
2108   static float __test(float);
2109   static double __test(char);
2110   static double __test(int);
2111   static double __test(unsigned);
2112   static double __test(long);
2113   static double __test(unsigned long);
2114   static double __test(long long);
2115   static double __test(unsigned long long);
2116   static double __test(double);
2117   static long double __test(long double);
2118
2119   typedef decltype(__test(declval<_Tp>())) type;
2120   static const bool value = _IsNotSame<type, void>::value;
2121};
2122
2123template <>
2124struct __numeric_type<void>
2125{
2126   static const bool value = true;
2127};
2128
2129// __promote
2130
2131template <class _A1, class _A2 = void, class _A3 = void,
2132          bool = __numeric_type<_A1>::value &&
2133                 __numeric_type<_A2>::value &&
2134                 __numeric_type<_A3>::value>
2135class __promote_imp
2136{
2137public:
2138    static const bool value = false;
2139};
2140
2141template <class _A1, class _A2, class _A3>
2142class __promote_imp<_A1, _A2, _A3, true>
2143{
2144private:
2145    typedef typename __promote_imp<_A1>::type __type1;
2146    typedef typename __promote_imp<_A2>::type __type2;
2147    typedef typename __promote_imp<_A3>::type __type3;
2148public:
2149    typedef decltype(__type1() + __type2() + __type3()) type;
2150    static const bool value = true;
2151};
2152
2153template <class _A1, class _A2>
2154class __promote_imp<_A1, _A2, void, true>
2155{
2156private:
2157    typedef typename __promote_imp<_A1>::type __type1;
2158    typedef typename __promote_imp<_A2>::type __type2;
2159public:
2160    typedef decltype(__type1() + __type2()) type;
2161    static const bool value = true;
2162};
2163
2164template <class _A1>
2165class __promote_imp<_A1, void, void, true>
2166{
2167public:
2168    typedef typename __numeric_type<_A1>::type type;
2169    static const bool value = true;
2170};
2171
2172template <class _A1, class _A2 = void, class _A3 = void>
2173class __promote : public __promote_imp<_A1, _A2, _A3> {};
2174
2175// make_signed / make_unsigned
2176
2177typedef
2178    __type_list<signed char,
2179    __type_list<signed short,
2180    __type_list<signed int,
2181    __type_list<signed long,
2182    __type_list<signed long long,
2183#ifndef _LIBCPP_HAS_NO_INT128
2184    __type_list<__int128_t,
2185#endif
2186    __nat
2187#ifndef _LIBCPP_HAS_NO_INT128
2188    >
2189#endif
2190    > > > > > __signed_types;
2191
2192typedef
2193    __type_list<unsigned char,
2194    __type_list<unsigned short,
2195    __type_list<unsigned int,
2196    __type_list<unsigned long,
2197    __type_list<unsigned long long,
2198#ifndef _LIBCPP_HAS_NO_INT128
2199    __type_list<__uint128_t,
2200#endif
2201    __nat
2202#ifndef _LIBCPP_HAS_NO_INT128
2203    >
2204#endif
2205    > > > > > __unsigned_types;
2206
2207template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2208
2209template <class _Hp, class _Tp, size_t _Size>
2210struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2211{
2212    typedef _LIBCPP_NODEBUG_TYPE _Hp type;
2213};
2214
2215template <class _Hp, class _Tp, size_t _Size>
2216struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2217{
2218    typedef _LIBCPP_NODEBUG_TYPE typename __find_first<_Tp, _Size>::type type;
2219};
2220
2221template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2222                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2223struct __apply_cv
2224{
2225    typedef _LIBCPP_NODEBUG_TYPE _Up type;
2226};
2227
2228template <class _Tp, class _Up>
2229struct __apply_cv<_Tp, _Up, true, false>
2230{
2231    typedef _LIBCPP_NODEBUG_TYPE const _Up type;
2232};
2233
2234template <class _Tp, class _Up>
2235struct __apply_cv<_Tp, _Up, false, true>
2236{
2237    typedef volatile _Up type;
2238};
2239
2240template <class _Tp, class _Up>
2241struct __apply_cv<_Tp, _Up, true, true>
2242{
2243    typedef const volatile _Up type;
2244};
2245
2246template <class _Tp, class _Up>
2247struct __apply_cv<_Tp&, _Up, false, false>
2248{
2249    typedef _Up& type;
2250};
2251
2252template <class _Tp, class _Up>
2253struct __apply_cv<_Tp&, _Up, true, false>
2254{
2255    typedef const _Up& type;
2256};
2257
2258template <class _Tp, class _Up>
2259struct __apply_cv<_Tp&, _Up, false, true>
2260{
2261    typedef volatile _Up& type;
2262};
2263
2264template <class _Tp, class _Up>
2265struct __apply_cv<_Tp&, _Up, true, true>
2266{
2267    typedef const volatile _Up& type;
2268};
2269
2270template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2271struct __make_signed {};
2272
2273template <class _Tp>
2274struct __make_signed<_Tp, true>
2275{
2276    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2277};
2278
2279template <> struct __make_signed<bool,               true> {};
2280template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2281template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2282template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2283template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2284template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2285template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2286template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2287template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2288#ifndef _LIBCPP_HAS_NO_INT128
2289template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2290template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2291#endif
2292
2293template <class _Tp>
2294struct _LIBCPP_TEMPLATE_VIS make_signed
2295{
2296    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2297};
2298
2299#if _LIBCPP_STD_VER > 11
2300template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2301#endif
2302
2303template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2304struct __make_unsigned {};
2305
2306template <class _Tp>
2307struct __make_unsigned<_Tp, true>
2308{
2309    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2310};
2311
2312template <> struct __make_unsigned<bool,               true> {};
2313template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2314template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2315template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2316template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2317template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2318template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2319template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2320template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2321#ifndef _LIBCPP_HAS_NO_INT128
2322template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2323template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2324#endif
2325
2326template <class _Tp>
2327struct _LIBCPP_TEMPLATE_VIS make_unsigned
2328{
2329    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2330};
2331
2332#if _LIBCPP_STD_VER > 11
2333template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2334#endif
2335
2336template <class _Tp, class _Up, class = void>
2337struct __common_type2_imp {};
2338
2339template <class _Tp, class _Up>
2340struct __common_type2_imp<_Tp, _Up,
2341                          typename __void_t<decltype(
2342                                            true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2343                                            )>::type>
2344{
2345  typedef _LIBCPP_NODEBUG_TYPE typename decay<decltype(
2346                         true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2347                         )>::type type;
2348};
2349
2350template <class, class = void>
2351struct __common_type_impl {};
2352
2353// Clang provides variadic templates in C++03 as an extension.
2354#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2355# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2356template <class... Tp>
2357struct __common_types;
2358template <class... _Tp>
2359struct _LIBCPP_TEMPLATE_VIS common_type;
2360#else
2361# define _LIBCPP_OPTIONAL_PACK(...)
2362struct __no_arg;
2363template <class _Tp, class _Up, class = __no_arg>
2364struct __common_types;
2365template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2366          class _Unused = __no_arg>
2367struct common_type {
2368  static_assert(sizeof(_Unused) == 0,
2369                "common_type accepts at most 3 arguments in C++03");
2370};
2371#endif // _LIBCPP_CXX03_LANG
2372
2373template <class _Tp, class _Up>
2374struct __common_type_impl<
2375    __common_types<_Tp, _Up>,
2376    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2377{
2378  typedef typename common_type<_Tp, _Up>::type type;
2379};
2380
2381template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2382struct __common_type_impl<
2383    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2384    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2385    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2386                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2387};
2388
2389// bullet 1 - sizeof...(Tp) == 0
2390
2391template <>
2392struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2393
2394// bullet 2 - sizeof...(Tp) == 1
2395
2396template <class _Tp>
2397struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2398    : public common_type<_Tp, _Tp> {};
2399
2400// bullet 3 - sizeof...(Tp) == 2
2401
2402template <class _Tp, class _Up>
2403struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2404    : conditional<
2405        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2406        __common_type2_imp<_Tp, _Up>,
2407        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2408    >::type
2409{};
2410
2411// bullet 4 - sizeof...(Tp) > 2
2412
2413template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2414struct _LIBCPP_TEMPLATE_VIS
2415    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2416    : __common_type_impl<
2417          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2418
2419#undef _LIBCPP_OPTIONAL_PACK
2420
2421#if _LIBCPP_STD_VER > 11
2422template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2423#endif
2424
2425// is_assignable
2426
2427template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
2428
2429#if __has_keyword(__is_assignable)
2430
2431template<class _Tp, class _Up>
2432struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2433
2434#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2435template <class _Tp, class _Arg>
2436_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v = __is_assignable(_Tp, _Arg);
2437#endif
2438
2439#else // __has_keyword(__is_assignable)
2440
2441template <class _Tp, class _Arg>
2442typename __select_2nd<decltype((_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>())), true_type>::type
2443__is_assignable_test(int);
2444
2445template <class, class>
2446false_type __is_assignable_test(...);
2447
2448
2449template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2450struct __is_assignable_imp
2451    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2452
2453template <class _Tp, class _Arg>
2454struct __is_assignable_imp<_Tp, _Arg, true>
2455    : public false_type
2456{
2457};
2458
2459template <class _Tp, class _Arg>
2460struct is_assignable
2461    : public __is_assignable_imp<_Tp, _Arg> {};
2462
2463#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2464template <class _Tp, class _Arg>
2465_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v
2466    = is_assignable<_Tp, _Arg>::value;
2467#endif
2468
2469#endif  // __has_keyword(__is_assignable)
2470
2471// is_copy_assignable
2472
2473template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2474    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2475                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2476
2477#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2478template <class _Tp>
2479_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_assignable_v
2480    = is_copy_assignable<_Tp>::value;
2481#endif
2482
2483// is_move_assignable
2484
2485template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2486    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2487                           typename add_rvalue_reference<_Tp>::type> {};
2488
2489#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2490template <class _Tp>
2491_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_assignable_v
2492    = is_move_assignable<_Tp>::value;
2493#endif
2494
2495// is_destructible
2496
2497#if __has_keyword(__is_destructible)
2498
2499template<class _Tp>
2500struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2501
2502#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2503template <class _Tp>
2504_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v = __is_destructible(_Tp);
2505#endif
2506
2507#else // __has_keyword(__is_destructible)
2508
2509//  if it's a reference, return true
2510//  if it's a function, return false
2511//  if it's   void,     return false
2512//  if it's an array of unknown bound, return false
2513//  Otherwise, return "std::declval<_Up&>().~_Up()" is well-formed
2514//    where _Up is remove_all_extents<_Tp>::type
2515
2516template <class>
2517struct __is_destructible_apply { typedef int type; };
2518
2519template <typename _Tp>
2520struct __is_destructor_wellformed {
2521    template <typename _Tp1>
2522    static char  __test (
2523        typename __is_destructible_apply<decltype(_VSTD::declval<_Tp1&>().~_Tp1())>::type
2524    );
2525
2526    template <typename _Tp1>
2527    static __two __test (...);
2528
2529    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2530};
2531
2532template <class _Tp, bool>
2533struct __destructible_imp;
2534
2535template <class _Tp>
2536struct __destructible_imp<_Tp, false>
2537   : public _VSTD::integral_constant<bool,
2538        __is_destructor_wellformed<typename _VSTD::remove_all_extents<_Tp>::type>::value> {};
2539
2540template <class _Tp>
2541struct __destructible_imp<_Tp, true>
2542    : public _VSTD::true_type {};
2543
2544template <class _Tp, bool>
2545struct __destructible_false;
2546
2547template <class _Tp>
2548struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, _VSTD::is_reference<_Tp>::value> {};
2549
2550template <class _Tp>
2551struct __destructible_false<_Tp, true> : public _VSTD::false_type {};
2552
2553template <class _Tp>
2554struct is_destructible
2555    : public __destructible_false<_Tp, _VSTD::is_function<_Tp>::value> {};
2556
2557template <class _Tp>
2558struct is_destructible<_Tp[]>
2559    : public _VSTD::false_type {};
2560
2561template <>
2562struct is_destructible<void>
2563    : public _VSTD::false_type {};
2564
2565#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2566template <class _Tp>
2567_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v
2568    = is_destructible<_Tp>::value;
2569#endif
2570
2571#endif // __has_keyword(__is_destructible)
2572
2573// move
2574
2575template <class _Tp>
2576inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2577typename remove_reference<_Tp>::type&&
2578move(_Tp&& __t) _NOEXCEPT
2579{
2580    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
2581    return static_cast<_Up&&>(__t);
2582}
2583
2584template <class _Tp>
2585inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2586_Tp&&
2587forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT
2588{
2589    return static_cast<_Tp&&>(__t);
2590}
2591
2592template <class _Tp>
2593inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2594_Tp&&
2595forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT
2596{
2597    static_assert(!is_lvalue_reference<_Tp>::value,
2598                  "can not forward an rvalue as an lvalue");
2599    return static_cast<_Tp&&>(__t);
2600}
2601
2602template <class _Tp>
2603inline _LIBCPP_INLINE_VISIBILITY
2604typename decay<_Tp>::type
2605__decay_copy(_Tp&& __t)
2606{
2607    return _VSTD::forward<_Tp>(__t);
2608}
2609
2610template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2611struct __member_pointer_traits_imp
2612{
2613};
2614
2615template <class _Rp, class _Class, class ..._Param>
2616struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2617{
2618    typedef _Class _ClassType;
2619    typedef _Rp _ReturnType;
2620    typedef _Rp (_FnType) (_Param...);
2621};
2622
2623template <class _Rp, class _Class, class ..._Param>
2624struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2625{
2626    typedef _Class _ClassType;
2627    typedef _Rp _ReturnType;
2628    typedef _Rp (_FnType) (_Param..., ...);
2629};
2630
2631template <class _Rp, class _Class, class ..._Param>
2632struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2633{
2634    typedef _Class const _ClassType;
2635    typedef _Rp _ReturnType;
2636    typedef _Rp (_FnType) (_Param...);
2637};
2638
2639template <class _Rp, class _Class, class ..._Param>
2640struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2641{
2642    typedef _Class const _ClassType;
2643    typedef _Rp _ReturnType;
2644    typedef _Rp (_FnType) (_Param..., ...);
2645};
2646
2647template <class _Rp, class _Class, class ..._Param>
2648struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2649{
2650    typedef _Class volatile _ClassType;
2651    typedef _Rp _ReturnType;
2652    typedef _Rp (_FnType) (_Param...);
2653};
2654
2655template <class _Rp, class _Class, class ..._Param>
2656struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2657{
2658    typedef _Class volatile _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...) const volatile, true, false>
2665{
2666    typedef _Class const volatile _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 volatile, true, false>
2673{
2674    typedef _Class const volatile _ClassType;
2675    typedef _Rp _ReturnType;
2676    typedef _Rp (_FnType) (_Param..., ...);
2677};
2678
2679#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2680
2681template <class _Rp, class _Class, class ..._Param>
2682struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2683{
2684    typedef _Class& _ClassType;
2685    typedef _Rp _ReturnType;
2686    typedef _Rp (_FnType) (_Param...);
2687};
2688
2689template <class _Rp, class _Class, class ..._Param>
2690struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2691{
2692    typedef _Class& _ClassType;
2693    typedef _Rp _ReturnType;
2694    typedef _Rp (_FnType) (_Param..., ...);
2695};
2696
2697template <class _Rp, class _Class, class ..._Param>
2698struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2699{
2700    typedef _Class const& _ClassType;
2701    typedef _Rp _ReturnType;
2702    typedef _Rp (_FnType) (_Param...);
2703};
2704
2705template <class _Rp, class _Class, class ..._Param>
2706struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2707{
2708    typedef _Class const& _ClassType;
2709    typedef _Rp _ReturnType;
2710    typedef _Rp (_FnType) (_Param..., ...);
2711};
2712
2713template <class _Rp, class _Class, class ..._Param>
2714struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2715{
2716    typedef _Class volatile& _ClassType;
2717    typedef _Rp _ReturnType;
2718    typedef _Rp (_FnType) (_Param...);
2719};
2720
2721template <class _Rp, class _Class, class ..._Param>
2722struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2723{
2724    typedef _Class volatile& _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...) const volatile&, true, false>
2731{
2732    typedef _Class const volatile& _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 volatile&, true, false>
2739{
2740    typedef _Class const volatile& _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...) &&, true, false>
2747{
2748    typedef _Class&& _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..., ...) &&, true, false>
2755{
2756    typedef _Class&& _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...) const&&, true, false>
2763{
2764    typedef _Class const&& _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&&, true, false>
2771{
2772    typedef _Class const&& _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...) volatile&&, true, false>
2779{
2780    typedef _Class 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..., ...) volatile&&, true, false>
2787{
2788    typedef _Class volatile&& _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...) const volatile&&, true, false>
2795{
2796    typedef _Class const volatile&& _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 volatile&&, true, false>
2803{
2804    typedef _Class const volatile&& _ClassType;
2805    typedef _Rp _ReturnType;
2806    typedef _Rp (_FnType) (_Param..., ...);
2807};
2808
2809#endif  // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2810
2811
2812template <class _Rp, class _Class>
2813struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2814{
2815    typedef _Class _ClassType;
2816    typedef _Rp _ReturnType;
2817};
2818
2819template <class _MP>
2820struct __member_pointer_traits
2821    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2822                    is_member_function_pointer<_MP>::value,
2823                    is_member_object_pointer<_MP>::value>
2824{
2825//     typedef ... _ClassType;
2826//     typedef ... _ReturnType;
2827//     typedef ... _FnType;
2828};
2829
2830
2831template <class _DecayedFp>
2832struct __member_pointer_class_type {};
2833
2834template <class _Ret, class _ClassType>
2835struct __member_pointer_class_type<_Ret _ClassType::*> {
2836  typedef _ClassType type;
2837};
2838
2839// result_of
2840
2841template <class _Callable> class result_of;
2842
2843#ifdef _LIBCPP_HAS_NO_VARIADICS
2844
2845template <class _Fn, bool, bool>
2846class __result_of
2847{
2848};
2849
2850template <class _Fn>
2851class __result_of<_Fn(), true, false>
2852{
2853public:
2854    typedef decltype(declval<_Fn>()()) type;
2855};
2856
2857template <class _Fn, class _A0>
2858class __result_of<_Fn(_A0), true, false>
2859{
2860public:
2861    typedef decltype(declval<_Fn>()(declval<_A0>())) type;
2862};
2863
2864template <class _Fn, class _A0, class _A1>
2865class __result_of<_Fn(_A0, _A1), true, false>
2866{
2867public:
2868    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>())) type;
2869};
2870
2871template <class _Fn, class _A0, class _A1, class _A2>
2872class __result_of<_Fn(_A0, _A1, _A2), true, false>
2873{
2874public:
2875    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>(), declval<_A2>())) type;
2876};
2877
2878template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
2879struct __result_of_mp;
2880
2881// member function pointer
2882
2883template <class _MP, class _Tp>
2884struct __result_of_mp<_MP, _Tp, true>
2885    : public __identity<typename __member_pointer_traits<_MP>::_ReturnType>
2886{
2887};
2888
2889// member data pointer
2890
2891template <class _MP, class _Tp, bool>
2892struct __result_of_mdp;
2893
2894template <class _Rp, class _Class, class _Tp>
2895struct __result_of_mdp<_Rp _Class::*, _Tp, false>
2896{
2897    typedef typename __apply_cv<decltype(*_VSTD::declval<_Tp>()), _Rp>::type& type;
2898};
2899
2900template <class _Rp, class _Class, class _Tp>
2901struct __result_of_mdp<_Rp _Class::*, _Tp, true>
2902{
2903    typedef typename __apply_cv<_Tp, _Rp>::type& type;
2904};
2905
2906template <class _Rp, class _Class, class _Tp>
2907struct __result_of_mp<_Rp _Class::*, _Tp, false>
2908    : public __result_of_mdp<_Rp _Class::*, _Tp,
2909            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
2910{
2911};
2912
2913
2914
2915template <class _Fn, class _Tp>
2916class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
2917    : public __result_of_mp<typename remove_reference<_Fn>::type,
2918                            _Tp,
2919                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2920{
2921};
2922
2923template <class _Fn, class _Tp, class _A0>
2924class __result_of<_Fn(_Tp, _A0), false, true>  // _Fn must be member pointer
2925    : public __result_of_mp<typename remove_reference<_Fn>::type,
2926                            _Tp,
2927                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2928{
2929};
2930
2931template <class _Fn, class _Tp, class _A0, class _A1>
2932class __result_of<_Fn(_Tp, _A0, _A1), false, true>  // _Fn must be member pointer
2933    : public __result_of_mp<typename remove_reference<_Fn>::type,
2934                            _Tp,
2935                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2936{
2937};
2938
2939template <class _Fn, class _Tp, class _A0, class _A1, class _A2>
2940class __result_of<_Fn(_Tp, _A0, _A1, _A2), false, true>  // _Fn must be member pointer
2941    : public __result_of_mp<typename remove_reference<_Fn>::type,
2942                            _Tp,
2943                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2944{
2945};
2946
2947// result_of
2948
2949template <class _Fn>
2950class _LIBCPP_TEMPLATE_VIS result_of<_Fn()>
2951    : public __result_of<_Fn(),
2952                         is_class<typename remove_reference<_Fn>::type>::value ||
2953                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2954                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2955                        >
2956{
2957};
2958
2959template <class _Fn, class _A0>
2960class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0)>
2961    : public __result_of<_Fn(_A0),
2962                         is_class<typename remove_reference<_Fn>::type>::value ||
2963                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2964                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2965                        >
2966{
2967};
2968
2969template <class _Fn, class _A0, class _A1>
2970class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0, _A1)>
2971    : public __result_of<_Fn(_A0, _A1),
2972                         is_class<typename remove_reference<_Fn>::type>::value ||
2973                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2974                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2975                        >
2976{
2977};
2978
2979template <class _Fn, class _A0, class _A1, class _A2>
2980class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_A0, _A1, _A2)>
2981    : public __result_of<_Fn(_A0, _A1, _A2),
2982                         is_class<typename remove_reference<_Fn>::type>::value ||
2983                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2984                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2985                        >
2986{
2987};
2988
2989#endif  // _LIBCPP_HAS_NO_VARIADICS
2990
2991// template <class T, class... Args> struct is_constructible;
2992
2993namespace __is_construct
2994{
2995struct __nat {};
2996}
2997
2998#if !defined(_LIBCPP_CXX03_LANG) && (!__has_feature(is_constructible) || \
2999    defined(_LIBCPP_TESTING_FALLBACK_IS_CONSTRUCTIBLE))
3000
3001template <class _Tp, class... _Args>
3002struct __libcpp_is_constructible;
3003
3004template <class _To, class _From>
3005struct __is_invalid_base_to_derived_cast {
3006  static_assert(is_reference<_To>::value, "Wrong specialization");
3007  using _RawFrom = __uncvref_t<_From>;
3008  using _RawTo = __uncvref_t<_To>;
3009  static const bool value = _And<
3010        _IsNotSame<_RawFrom, _RawTo>,
3011        is_base_of<_RawFrom, _RawTo>,
3012        _Not<__libcpp_is_constructible<_RawTo, _From>>
3013  >::value;
3014};
3015
3016template <class _To, class _From>
3017struct __is_invalid_lvalue_to_rvalue_cast : false_type {
3018  static_assert(is_reference<_To>::value, "Wrong specialization");
3019};
3020
3021template <class _ToRef, class _FromRef>
3022struct __is_invalid_lvalue_to_rvalue_cast<_ToRef&&, _FromRef&> {
3023  using _RawFrom = __uncvref_t<_FromRef>;
3024  using _RawTo = __uncvref_t<_ToRef>;
3025  static const bool value = _And<
3026      _Not<is_function<_RawTo>>,
3027      _Or<
3028        _IsSame<_RawFrom, _RawTo>,
3029        is_base_of<_RawTo, _RawFrom>>
3030    >::value;
3031};
3032
3033struct __is_constructible_helper
3034{
3035    template <class _To>
3036    static void __eat(_To);
3037
3038    // This overload is needed to work around a Clang bug that disallows
3039    // static_cast<T&&>(e) for non-reference-compatible types.
3040    // Example: static_cast<int&&>(declval<double>());
3041    // NOTE: The static_cast implementation below is required to support
3042    //  classes with explicit conversion operators.
3043    template <class _To, class _From,
3044              class = decltype(__eat<_To>(_VSTD::declval<_From>()))>
3045    static true_type __test_cast(int);
3046
3047    template <class _To, class _From,
3048              class = decltype(static_cast<_To>(_VSTD::declval<_From>()))>
3049    static integral_constant<bool,
3050        !__is_invalid_base_to_derived_cast<_To, _From>::value &&
3051        !__is_invalid_lvalue_to_rvalue_cast<_To, _From>::value
3052    > __test_cast(long);
3053
3054    template <class, class>
3055    static false_type __test_cast(...);
3056
3057    template <class _Tp, class ..._Args,
3058        class = decltype(_Tp(_VSTD::declval<_Args>()...))>
3059    static true_type __test_nary(int);
3060    template <class _Tp, class...>
3061    static false_type __test_nary(...);
3062
3063    template <class _Tp, class _A0, class = decltype(::new _Tp(_VSTD::declval<_A0>()))>
3064    static is_destructible<_Tp> __test_unary(int);
3065    template <class, class>
3066    static false_type __test_unary(...);
3067};
3068
3069template <class _Tp, bool = is_void<_Tp>::value>
3070struct __is_default_constructible
3071    : decltype(__is_constructible_helper::__test_nary<_Tp>(0))
3072{};
3073
3074template <class _Tp>
3075struct __is_default_constructible<_Tp, true> : false_type {};
3076
3077template <class _Tp>
3078struct __is_default_constructible<_Tp[], false> : false_type {};
3079
3080template <class _Tp, size_t _Nx>
3081struct __is_default_constructible<_Tp[_Nx], false>
3082    : __is_default_constructible<typename remove_all_extents<_Tp>::type>  {};
3083
3084template <class _Tp, class... _Args>
3085struct __libcpp_is_constructible
3086{
3087  static_assert(sizeof...(_Args) > 1, "Wrong specialization");
3088  typedef decltype(__is_constructible_helper::__test_nary<_Tp, _Args...>(0))
3089      type;
3090};
3091
3092template <class _Tp>
3093struct __libcpp_is_constructible<_Tp> : __is_default_constructible<_Tp> {};
3094
3095template <class _Tp, class _A0>
3096struct __libcpp_is_constructible<_Tp, _A0>
3097    : public decltype(__is_constructible_helper::__test_unary<_Tp, _A0>(0))
3098{};
3099
3100template <class _Tp, class _A0>
3101struct __libcpp_is_constructible<_Tp&, _A0>
3102    : public decltype(__is_constructible_helper::
3103    __test_cast<_Tp&, _A0>(0))
3104{};
3105
3106template <class _Tp, class _A0>
3107struct __libcpp_is_constructible<_Tp&&, _A0>
3108    : public decltype(__is_constructible_helper::
3109    __test_cast<_Tp&&, _A0>(0))
3110{};
3111
3112#endif
3113
3114#if __has_feature(is_constructible)
3115template <class _Tp, class ..._Args>
3116struct _LIBCPP_TEMPLATE_VIS is_constructible
3117    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
3118    {};
3119#else
3120template <class _Tp, class... _Args>
3121struct _LIBCPP_TEMPLATE_VIS is_constructible
3122    : public __libcpp_is_constructible<_Tp, _Args...>::type {};
3123#endif
3124
3125#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3126template <class _Tp, class ..._Args>
3127_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_constructible_v
3128    = is_constructible<_Tp, _Args...>::value;
3129#endif
3130
3131// is_default_constructible
3132
3133template <class _Tp>
3134struct _LIBCPP_TEMPLATE_VIS is_default_constructible
3135    : public is_constructible<_Tp>
3136    {};
3137
3138#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3139template <class _Tp>
3140_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_default_constructible_v
3141    = is_default_constructible<_Tp>::value;
3142#endif
3143
3144#ifndef _LIBCPP_CXX03_LANG
3145// First of all, we can't implement this check in C++03 mode because the {}
3146// default initialization syntax isn't valid.
3147// Second, we implement the trait in a funny manner with two defaulted template
3148// arguments to workaround Clang's PR43454.
3149template <class _Tp>
3150void __test_implicit_default_constructible(_Tp);
3151
3152template <class _Tp, class = void, bool = is_default_constructible<_Tp>::value>
3153struct __is_implicitly_default_constructible
3154    : false_type
3155{ };
3156
3157template <class _Tp>
3158struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true>
3159    : true_type
3160{ };
3161
3162template <class _Tp>
3163struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false>
3164    : false_type
3165{ };
3166#endif // !C++03
3167
3168// is_copy_constructible
3169
3170template <class _Tp>
3171struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
3172    : public is_constructible<_Tp,
3173                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3174
3175#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3176template <class _Tp>
3177_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_constructible_v
3178    = is_copy_constructible<_Tp>::value;
3179#endif
3180
3181// is_move_constructible
3182
3183template <class _Tp>
3184struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3185    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3186    {};
3187
3188#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3189template <class _Tp>
3190_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_constructible_v
3191    = is_move_constructible<_Tp>::value;
3192#endif
3193
3194// is_trivially_constructible
3195
3196#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3197
3198template <class _Tp, class... _Args>
3199struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3200    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3201{
3202};
3203
3204#else  // !__has_feature(is_trivially_constructible)
3205
3206template <class _Tp, class... _Args>
3207struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3208    : false_type
3209{
3210};
3211
3212template <class _Tp>
3213struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp>
3214#if __has_feature(has_trivial_constructor) || defined(_LIBCPP_COMPILER_GCC)
3215    : integral_constant<bool, __has_trivial_constructor(_Tp)>
3216#else
3217    : integral_constant<bool, is_scalar<_Tp>::value>
3218#endif
3219{
3220};
3221
3222template <class _Tp>
3223struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&&>
3224    : integral_constant<bool, is_scalar<_Tp>::value>
3225{
3226};
3227
3228template <class _Tp>
3229struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, const _Tp&>
3230    : integral_constant<bool, is_scalar<_Tp>::value>
3231{
3232};
3233
3234template <class _Tp>
3235struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&>
3236    : integral_constant<bool, is_scalar<_Tp>::value>
3237{
3238};
3239
3240#endif  // !__has_feature(is_trivially_constructible)
3241
3242
3243#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3244template <class _Tp, class... _Args>
3245_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_constructible_v
3246    = is_trivially_constructible<_Tp, _Args...>::value;
3247#endif
3248
3249// is_trivially_default_constructible
3250
3251template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3252    : public is_trivially_constructible<_Tp>
3253    {};
3254
3255#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3256template <class _Tp>
3257_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_default_constructible_v
3258    = is_trivially_default_constructible<_Tp>::value;
3259#endif
3260
3261// is_trivially_copy_constructible
3262
3263template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3264    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3265    {};
3266
3267#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3268template <class _Tp>
3269_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_constructible_v
3270    = is_trivially_copy_constructible<_Tp>::value;
3271#endif
3272
3273// is_trivially_move_constructible
3274
3275template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3276    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3277    {};
3278
3279#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3280template <class _Tp>
3281_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_constructible_v
3282    = is_trivially_move_constructible<_Tp>::value;
3283#endif
3284
3285// is_trivially_assignable
3286
3287#if __has_feature(is_trivially_assignable) || _GNUC_VER >= 501
3288
3289template <class _Tp, class _Arg>
3290struct is_trivially_assignable
3291    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3292{
3293};
3294
3295#else  // !__has_feature(is_trivially_assignable)
3296
3297template <class _Tp, class _Arg>
3298struct is_trivially_assignable
3299    : public false_type {};
3300
3301template <class _Tp>
3302struct is_trivially_assignable<_Tp&, _Tp>
3303    : integral_constant<bool, is_scalar<_Tp>::value> {};
3304
3305template <class _Tp>
3306struct is_trivially_assignable<_Tp&, _Tp&>
3307    : integral_constant<bool, is_scalar<_Tp>::value> {};
3308
3309template <class _Tp>
3310struct is_trivially_assignable<_Tp&, const _Tp&>
3311    : integral_constant<bool, is_scalar<_Tp>::value> {};
3312
3313template <class _Tp>
3314struct is_trivially_assignable<_Tp&, _Tp&&>
3315    : integral_constant<bool, is_scalar<_Tp>::value> {};
3316
3317#endif  // !__has_feature(is_trivially_assignable)
3318
3319#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3320template <class _Tp, class _Arg>
3321_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_assignable_v
3322    = is_trivially_assignable<_Tp, _Arg>::value;
3323#endif
3324
3325// is_trivially_copy_assignable
3326
3327template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3328    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3329                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3330
3331#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3332template <class _Tp>
3333_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_assignable_v
3334    = is_trivially_copy_assignable<_Tp>::value;
3335#endif
3336
3337// is_trivially_move_assignable
3338
3339template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3340    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3341                                     typename add_rvalue_reference<_Tp>::type>
3342    {};
3343
3344#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3345template <class _Tp>
3346_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_assignable_v
3347    = is_trivially_move_assignable<_Tp>::value;
3348#endif
3349
3350// is_trivially_destructible
3351
3352#if __has_keyword(__is_trivially_destructible)
3353
3354template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3355    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3356
3357#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3358
3359template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3360    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3361
3362#else
3363
3364template <class _Tp> struct __libcpp_trivial_destructor
3365    : public integral_constant<bool, is_scalar<_Tp>::value ||
3366                                     is_reference<_Tp>::value> {};
3367
3368template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3369    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3370
3371template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3372    : public false_type {};
3373
3374#endif
3375
3376#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3377template <class _Tp>
3378_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_destructible_v
3379    = is_trivially_destructible<_Tp>::value;
3380#endif
3381
3382// is_nothrow_constructible
3383
3384#if __has_keyword(__is_nothrow_constructible)
3385
3386template <class _Tp, class... _Args>
3387struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3388    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3389
3390#else
3391
3392template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3393
3394template <class _Tp, class... _Args>
3395struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3396    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3397{
3398};
3399
3400template <class _Tp>
3401void __implicit_conversion_to(_Tp) noexcept { }
3402
3403template <class _Tp, class _Arg>
3404struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3405    : public integral_constant<bool, noexcept(__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3406{
3407};
3408
3409template <class _Tp, bool _IsReference, class... _Args>
3410struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3411    : public false_type
3412{
3413};
3414
3415template <class _Tp, class... _Args>
3416struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3417    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3418{
3419};
3420
3421template <class _Tp, size_t _Ns>
3422struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3423    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3424{
3425};
3426
3427#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3428
3429
3430#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3431template <class _Tp, class ..._Args>
3432_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_constructible_v
3433    = is_nothrow_constructible<_Tp, _Args...>::value;
3434#endif
3435
3436// is_nothrow_default_constructible
3437
3438template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3439    : public is_nothrow_constructible<_Tp>
3440    {};
3441
3442#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3443template <class _Tp>
3444_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_default_constructible_v
3445    = is_nothrow_default_constructible<_Tp>::value;
3446#endif
3447
3448// is_nothrow_copy_constructible
3449
3450template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3451    : public is_nothrow_constructible<_Tp,
3452                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3453
3454#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3455template <class _Tp>
3456_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_constructible_v
3457    = is_nothrow_copy_constructible<_Tp>::value;
3458#endif
3459
3460// is_nothrow_move_constructible
3461
3462template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3463    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3464    {};
3465
3466#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3467template <class _Tp>
3468_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_constructible_v
3469    = is_nothrow_move_constructible<_Tp>::value;
3470#endif
3471
3472// is_nothrow_assignable
3473
3474#if __has_keyword(__is_nothrow_assignable)
3475
3476template <class _Tp, class _Arg>
3477struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3478    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3479
3480#else
3481
3482template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3483
3484template <class _Tp, class _Arg>
3485struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3486    : public false_type
3487{
3488};
3489
3490template <class _Tp, class _Arg>
3491struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3492    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>()) >
3493{
3494};
3495
3496template <class _Tp, class _Arg>
3497struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3498    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3499{
3500};
3501
3502#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3503
3504#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3505template <class _Tp, class _Arg>
3506_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_assignable_v
3507    = is_nothrow_assignable<_Tp, _Arg>::value;
3508#endif
3509
3510// is_nothrow_copy_assignable
3511
3512template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3513    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3514                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3515
3516#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3517template <class _Tp>
3518_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_assignable_v
3519    = is_nothrow_copy_assignable<_Tp>::value;
3520#endif
3521
3522// is_nothrow_move_assignable
3523
3524template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3525    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3526                                     typename add_rvalue_reference<_Tp>::type>
3527    {};
3528
3529#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3530template <class _Tp>
3531_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_assignable_v
3532    = is_nothrow_move_assignable<_Tp>::value;
3533#endif
3534
3535// is_nothrow_destructible
3536
3537#if !defined(_LIBCPP_CXX03_LANG)
3538
3539template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3540
3541template <class _Tp>
3542struct __libcpp_is_nothrow_destructible<false, _Tp>
3543    : public false_type
3544{
3545};
3546
3547template <class _Tp>
3548struct __libcpp_is_nothrow_destructible<true, _Tp>
3549    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>().~_Tp()) >
3550{
3551};
3552
3553template <class _Tp>
3554struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3555    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3556{
3557};
3558
3559template <class _Tp, size_t _Ns>
3560struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3561    : public is_nothrow_destructible<_Tp>
3562{
3563};
3564
3565template <class _Tp>
3566struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3567    : public true_type
3568{
3569};
3570
3571template <class _Tp>
3572struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3573    : public true_type
3574{
3575};
3576
3577#else
3578
3579template <class _Tp> struct __libcpp_nothrow_destructor
3580    : public integral_constant<bool, is_scalar<_Tp>::value ||
3581                                     is_reference<_Tp>::value> {};
3582
3583template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3584    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3585
3586template <class _Tp>
3587struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3588    : public false_type {};
3589
3590#endif
3591
3592#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3593template <class _Tp>
3594_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_destructible_v
3595    = is_nothrow_destructible<_Tp>::value;
3596#endif
3597
3598// is_pod
3599
3600#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3601
3602template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3603    : public integral_constant<bool, __is_pod(_Tp)> {};
3604
3605#else
3606
3607template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3608    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3609                                     is_trivially_copy_constructible<_Tp>::value      &&
3610                                     is_trivially_copy_assignable<_Tp>::value    &&
3611                                     is_trivially_destructible<_Tp>::value> {};
3612
3613#endif
3614
3615#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3616template <class _Tp>
3617_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pod_v
3618    = is_pod<_Tp>::value;
3619#endif
3620
3621// is_literal_type;
3622
3623template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_literal_type
3624    : public integral_constant<bool, __is_literal_type(_Tp)>
3625    {};
3626
3627#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3628template <class _Tp>
3629_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_literal_type_v
3630    = is_literal_type<_Tp>::value;
3631#endif
3632
3633// is_standard_layout;
3634
3635template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3636#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3637    : public integral_constant<bool, __is_standard_layout(_Tp)>
3638#else
3639    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3640#endif
3641    {};
3642
3643#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3644template <class _Tp>
3645_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_standard_layout_v
3646    = is_standard_layout<_Tp>::value;
3647#endif
3648
3649// is_trivially_copyable;
3650
3651template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3652#if __has_feature(is_trivially_copyable)
3653    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3654#elif _GNUC_VER >= 501
3655    : public integral_constant<bool, !is_volatile<_Tp>::value && __is_trivially_copyable(_Tp)>
3656#else
3657    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3658#endif
3659    {};
3660
3661#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3662template <class _Tp>
3663_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copyable_v
3664    = is_trivially_copyable<_Tp>::value;
3665#endif
3666
3667// is_trivial;
3668
3669template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3670#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3671    : public integral_constant<bool, __is_trivial(_Tp)>
3672#else
3673    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3674                                 is_trivially_default_constructible<_Tp>::value>
3675#endif
3676    {};
3677
3678#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3679template <class _Tp>
3680_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivial_v
3681    = is_trivial<_Tp>::value;
3682#endif
3683
3684template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3685template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3686template <class _Tp> struct __is_reference_wrapper
3687    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3688
3689#ifndef _LIBCPP_CXX03_LANG
3690
3691template <class _Fp, class _A0,
3692         class _DecayFp = typename decay<_Fp>::type,
3693         class _DecayA0 = typename decay<_A0>::type,
3694         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3695using __enable_if_bullet1 = typename enable_if
3696    <
3697        is_member_function_pointer<_DecayFp>::value
3698        && is_base_of<_ClassT, _DecayA0>::value
3699    >::type;
3700
3701template <class _Fp, class _A0,
3702         class _DecayFp = typename decay<_Fp>::type,
3703         class _DecayA0 = typename decay<_A0>::type>
3704using __enable_if_bullet2 = typename enable_if
3705    <
3706        is_member_function_pointer<_DecayFp>::value
3707        && __is_reference_wrapper<_DecayA0>::value
3708    >::type;
3709
3710template <class _Fp, class _A0,
3711         class _DecayFp = typename decay<_Fp>::type,
3712         class _DecayA0 = typename decay<_A0>::type,
3713         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3714using __enable_if_bullet3 = typename enable_if
3715    <
3716        is_member_function_pointer<_DecayFp>::value
3717        && !is_base_of<_ClassT, _DecayA0>::value
3718        && !__is_reference_wrapper<_DecayA0>::value
3719    >::type;
3720
3721template <class _Fp, class _A0,
3722         class _DecayFp = typename decay<_Fp>::type,
3723         class _DecayA0 = typename decay<_A0>::type,
3724         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3725using __enable_if_bullet4 = typename enable_if
3726    <
3727        is_member_object_pointer<_DecayFp>::value
3728        && is_base_of<_ClassT, _DecayA0>::value
3729    >::type;
3730
3731template <class _Fp, class _A0,
3732         class _DecayFp = typename decay<_Fp>::type,
3733         class _DecayA0 = typename decay<_A0>::type>
3734using __enable_if_bullet5 = typename enable_if
3735    <
3736        is_member_object_pointer<_DecayFp>::value
3737        && __is_reference_wrapper<_DecayA0>::value
3738    >::type;
3739
3740template <class _Fp, class _A0,
3741         class _DecayFp = typename decay<_Fp>::type,
3742         class _DecayA0 = typename decay<_A0>::type,
3743         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3744using __enable_if_bullet6 = typename enable_if
3745    <
3746        is_member_object_pointer<_DecayFp>::value
3747        && !is_base_of<_ClassT, _DecayA0>::value
3748        && !__is_reference_wrapper<_DecayA0>::value
3749    >::type;
3750
3751// __invoke forward declarations
3752
3753// fall back - none of the bullets
3754
3755#define _LIBCPP_INVOKE_RETURN(...) \
3756    noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) \
3757    { return __VA_ARGS__; }
3758
3759template <class ..._Args>
3760auto __invoke(__any, _Args&& ...__args) -> __nat;
3761
3762template <class ..._Args>
3763auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3764
3765// bullets 1, 2 and 3
3766
3767template <class _Fp, class _A0, class ..._Args,
3768          class = __enable_if_bullet1<_Fp, _A0>>
3769inline _LIBCPP_INLINE_VISIBILITY
3770auto
3771__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3772_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3773
3774template <class _Fp, class _A0, class ..._Args,
3775          class = __enable_if_bullet1<_Fp, _A0>>
3776inline _LIBCPP_INLINE_VISIBILITY
3777_LIBCPP_CONSTEXPR auto
3778__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3779_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3780
3781template <class _Fp, class _A0, class ..._Args,
3782          class = __enable_if_bullet2<_Fp, _A0>>
3783inline _LIBCPP_INLINE_VISIBILITY
3784auto
3785__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3786_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3787
3788template <class _Fp, class _A0, class ..._Args,
3789          class = __enable_if_bullet2<_Fp, _A0>>
3790inline _LIBCPP_INLINE_VISIBILITY
3791_LIBCPP_CONSTEXPR auto
3792__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3793_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3794
3795template <class _Fp, class _A0, class ..._Args,
3796          class = __enable_if_bullet3<_Fp, _A0>>
3797inline _LIBCPP_INLINE_VISIBILITY
3798auto
3799__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3800_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3801
3802template <class _Fp, class _A0, class ..._Args,
3803          class = __enable_if_bullet3<_Fp, _A0>>
3804inline _LIBCPP_INLINE_VISIBILITY
3805_LIBCPP_CONSTEXPR auto
3806__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3807_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3808
3809// bullets 4, 5 and 6
3810
3811template <class _Fp, class _A0,
3812          class = __enable_if_bullet4<_Fp, _A0>>
3813inline _LIBCPP_INLINE_VISIBILITY
3814auto
3815__invoke(_Fp&& __f, _A0&& __a0)
3816_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3817
3818template <class _Fp, class _A0,
3819          class = __enable_if_bullet4<_Fp, _A0>>
3820inline _LIBCPP_INLINE_VISIBILITY
3821_LIBCPP_CONSTEXPR auto
3822__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3823_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3824
3825template <class _Fp, class _A0,
3826          class = __enable_if_bullet5<_Fp, _A0>>
3827inline _LIBCPP_INLINE_VISIBILITY
3828auto
3829__invoke(_Fp&& __f, _A0&& __a0)
3830_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3831
3832template <class _Fp, class _A0,
3833          class = __enable_if_bullet5<_Fp, _A0>>
3834inline _LIBCPP_INLINE_VISIBILITY
3835_LIBCPP_CONSTEXPR auto
3836__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3837_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3838
3839template <class _Fp, class _A0,
3840          class = __enable_if_bullet6<_Fp, _A0>>
3841inline _LIBCPP_INLINE_VISIBILITY
3842auto
3843__invoke(_Fp&& __f, _A0&& __a0)
3844_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3845
3846template <class _Fp, class _A0,
3847          class = __enable_if_bullet6<_Fp, _A0>>
3848inline _LIBCPP_INLINE_VISIBILITY
3849_LIBCPP_CONSTEXPR auto
3850__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3851_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3852
3853// bullet 7
3854
3855template <class _Fp, class ..._Args>
3856inline _LIBCPP_INLINE_VISIBILITY
3857auto
3858__invoke(_Fp&& __f, _Args&& ...__args)
3859_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3860
3861template <class _Fp, class ..._Args>
3862inline _LIBCPP_INLINE_VISIBILITY
3863_LIBCPP_CONSTEXPR auto
3864__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3865_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3866
3867#undef _LIBCPP_INVOKE_RETURN
3868
3869// __invokable
3870template <class _Ret, class _Fp, class ..._Args>
3871struct __invokable_r
3872{
3873  template <class _XFp, class ..._XArgs>
3874  static auto __try_call(int) -> decltype(
3875    _VSTD::__invoke(_VSTD::declval<_XFp>(), _VSTD::declval<_XArgs>()...));
3876  template <class _XFp, class ..._XArgs>
3877  static __nat __try_call(...);
3878
3879  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3880  // or incomplete array types as required by the standard.
3881  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3882
3883  using type =
3884  typename conditional<
3885      _IsNotSame<_Result, __nat>::value,
3886      typename conditional<
3887          is_void<_Ret>::value,
3888          true_type,
3889          is_convertible<_Result, _Ret>
3890      >::type,
3891      false_type
3892  >::type;
3893  static const bool value = type::value;
3894};
3895template <class _Fp, class ..._Args>
3896using __invokable = __invokable_r<void, _Fp, _Args...>;
3897
3898template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3899struct __nothrow_invokable_r_imp {
3900  static const bool value = false;
3901};
3902
3903template <class _Ret, class _Fp, class ..._Args>
3904struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3905{
3906    typedef __nothrow_invokable_r_imp _ThisT;
3907
3908    template <class _Tp>
3909    static void __test_noexcept(_Tp) noexcept;
3910
3911    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3912        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...)));
3913};
3914
3915template <class _Ret, class _Fp, class ..._Args>
3916struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3917{
3918    static const bool value = noexcept(
3919        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...));
3920};
3921
3922template <class _Ret, class _Fp, class ..._Args>
3923using __nothrow_invokable_r =
3924    __nothrow_invokable_r_imp<
3925            __invokable_r<_Ret, _Fp, _Args...>::value,
3926            is_void<_Ret>::value,
3927            _Ret, _Fp, _Args...
3928    >;
3929
3930template <class _Fp, class ..._Args>
3931using __nothrow_invokable =
3932    __nothrow_invokable_r_imp<
3933            __invokable<_Fp, _Args...>::value,
3934            true, void, _Fp, _Args...
3935    >;
3936
3937template <class _Fp, class ..._Args>
3938struct __invoke_of
3939    : public enable_if<
3940        __invokable<_Fp, _Args...>::value,
3941        typename __invokable_r<void, _Fp, _Args...>::_Result>
3942{
3943};
3944
3945// result_of
3946
3947template <class _Fp, class ..._Args>
3948class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3949    : public __invoke_of<_Fp, _Args...>
3950{
3951};
3952
3953#if _LIBCPP_STD_VER > 11
3954template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
3955#endif
3956
3957#if _LIBCPP_STD_VER > 14
3958
3959// invoke_result
3960
3961template <class _Fn, class... _Args>
3962struct _LIBCPP_TEMPLATE_VIS invoke_result
3963    : __invoke_of<_Fn, _Args...>
3964{
3965};
3966
3967template <class _Fn, class... _Args>
3968using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3969
3970// is_invocable
3971
3972template <class _Fn, class ..._Args>
3973struct _LIBCPP_TEMPLATE_VIS is_invocable
3974    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
3975
3976template <class _Ret, class _Fn, class ..._Args>
3977struct _LIBCPP_TEMPLATE_VIS is_invocable_r
3978    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
3979
3980template <class _Fn, class ..._Args>
3981_LIBCPP_INLINE_VAR constexpr bool is_invocable_v
3982    = is_invocable<_Fn, _Args...>::value;
3983
3984template <class _Ret, class _Fn, class ..._Args>
3985_LIBCPP_INLINE_VAR constexpr bool is_invocable_r_v
3986    = is_invocable_r<_Ret, _Fn, _Args...>::value;
3987
3988// is_nothrow_invocable
3989
3990template <class _Fn, class ..._Args>
3991struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
3992    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
3993
3994template <class _Ret, class _Fn, class ..._Args>
3995struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
3996    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
3997
3998template <class _Fn, class ..._Args>
3999_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_v
4000    = is_nothrow_invocable<_Fn, _Args...>::value;
4001
4002template <class _Ret, class _Fn, class ..._Args>
4003_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_r_v
4004    = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
4005
4006#endif // _LIBCPP_STD_VER > 14
4007
4008#endif  // !defined(_LIBCPP_CXX03_LANG)
4009
4010template <class _Tp> struct __is_swappable;
4011template <class _Tp> struct __is_nothrow_swappable;
4012
4013// swap, swap_ranges
4014
4015template <class _ForwardIterator1, class _ForwardIterator2>
4016inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4017_ForwardIterator2
4018swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2);
4019
4020template <class _Tp>
4021inline _LIBCPP_INLINE_VISIBILITY
4022#ifndef _LIBCPP_CXX03_LANG
4023typename enable_if
4024<
4025    is_move_constructible<_Tp>::value &&
4026    is_move_assignable<_Tp>::value
4027>::type
4028#else
4029void
4030#endif
4031_LIBCPP_CONSTEXPR_AFTER_CXX17
4032swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
4033                                    is_nothrow_move_assignable<_Tp>::value)
4034{
4035    _Tp __t(_VSTD::move(__x));
4036    __x = _VSTD::move(__y);
4037    __y = _VSTD::move(__t);
4038}
4039
4040template<class _Tp, size_t _Np>
4041inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4042typename enable_if<
4043    __is_swappable<_Tp>::value
4044>::type
4045swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
4046{
4047    _VSTD::swap_ranges(__a, __a + _Np, __b);
4048}
4049
4050template <class _ForwardIterator1, class _ForwardIterator2>
4051inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4052_ForwardIterator2
4053swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
4054{
4055    for(; __first1 != __last1; ++__first1, (void) ++__first2)
4056        swap(*__first1, *__first2);
4057    return __first2;
4058}
4059
4060// iter_swap
4061
4062template <class _ForwardIterator1, class _ForwardIterator2>
4063inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
4064void
4065iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
4066    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
4067               _NOEXCEPT_(_NOEXCEPT_(swap(*_VSTD::declval<_ForwardIterator1>(),
4068                                          *_VSTD::declval<_ForwardIterator2>())))
4069{
4070    swap(*__a, *__b);
4071}
4072
4073// __swappable
4074
4075namespace __detail
4076{
4077// ALL generic swap overloads MUST already have a declaration available at this point.
4078
4079template <class _Tp, class _Up = _Tp,
4080          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
4081struct __swappable_with
4082{
4083    template <class _LHS, class _RHS>
4084    static decltype(swap(_VSTD::declval<_LHS>(), _VSTD::declval<_RHS>()))
4085    __test_swap(int);
4086    template <class, class>
4087    static __nat __test_swap(long);
4088
4089    // Extra parens are needed for the C++03 definition of decltype.
4090    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
4091    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
4092
4093    static const bool value = _IsNotSame<__swap1, __nat>::value
4094                           && _IsNotSame<__swap2, __nat>::value;
4095};
4096
4097template <class _Tp, class _Up>
4098struct __swappable_with<_Tp, _Up,  false> : false_type {};
4099
4100template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
4101struct __nothrow_swappable_with {
4102  static const bool value =
4103#ifndef _LIBCPP_HAS_NO_NOEXCEPT
4104      noexcept(swap(_VSTD::declval<_Tp>(), _VSTD::declval<_Up>()))
4105  &&  noexcept(swap(_VSTD::declval<_Up>(), _VSTD::declval<_Tp>()));
4106#else
4107      false;
4108#endif
4109};
4110
4111template <class _Tp, class _Up>
4112struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
4113
4114}  // __detail
4115
4116template <class _Tp>
4117struct __is_swappable
4118    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
4119{
4120};
4121
4122template <class _Tp>
4123struct __is_nothrow_swappable
4124    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
4125{
4126};
4127
4128#if _LIBCPP_STD_VER > 14
4129
4130template <class _Tp, class _Up>
4131struct _LIBCPP_TEMPLATE_VIS is_swappable_with
4132    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
4133{
4134};
4135
4136template <class _Tp>
4137struct _LIBCPP_TEMPLATE_VIS is_swappable
4138    : public conditional<
4139        __is_referenceable<_Tp>::value,
4140        is_swappable_with<
4141            typename add_lvalue_reference<_Tp>::type,
4142            typename add_lvalue_reference<_Tp>::type>,
4143        false_type
4144    >::type
4145{
4146};
4147
4148template <class _Tp, class _Up>
4149struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
4150    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
4151{
4152};
4153
4154template <class _Tp>
4155struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
4156    : public conditional<
4157        __is_referenceable<_Tp>::value,
4158        is_nothrow_swappable_with<
4159            typename add_lvalue_reference<_Tp>::type,
4160            typename add_lvalue_reference<_Tp>::type>,
4161        false_type
4162    >::type
4163{
4164};
4165
4166template <class _Tp, class _Up>
4167_LIBCPP_INLINE_VAR constexpr bool is_swappable_with_v
4168    = is_swappable_with<_Tp, _Up>::value;
4169
4170template <class _Tp>
4171_LIBCPP_INLINE_VAR constexpr bool is_swappable_v
4172    = is_swappable<_Tp>::value;
4173
4174template <class _Tp, class _Up>
4175_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_with_v
4176    = is_nothrow_swappable_with<_Tp, _Up>::value;
4177
4178template <class _Tp>
4179_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_v
4180    = is_nothrow_swappable<_Tp>::value;
4181
4182#endif // _LIBCPP_STD_VER > 14
4183
4184template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4185
4186template <class _Tp>
4187struct __underlying_type_impl<_Tp, false> {};
4188
4189template <class _Tp>
4190struct __underlying_type_impl<_Tp, true>
4191{
4192    typedef __underlying_type(_Tp) type;
4193};
4194
4195template <class _Tp>
4196struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4197
4198#if _LIBCPP_STD_VER > 11
4199template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4200#endif
4201
4202template <class _Tp, bool = is_enum<_Tp>::value>
4203struct __sfinae_underlying_type
4204{
4205    typedef typename underlying_type<_Tp>::type type;
4206    typedef decltype(((type)1) + 0) __promoted_type;
4207};
4208
4209template <class _Tp>
4210struct __sfinae_underlying_type<_Tp, false> {};
4211
4212inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4213int __convert_to_integral(int __val) { return __val; }
4214
4215inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4216unsigned __convert_to_integral(unsigned __val) { return __val; }
4217
4218inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4219long __convert_to_integral(long __val) { return __val; }
4220
4221inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4222unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4223
4224inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4225long long __convert_to_integral(long long __val) { return __val; }
4226
4227inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4228unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4229
4230template<typename _Fp>
4231inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4232typename enable_if<is_floating_point<_Fp>::value, long long>::type
4233 __convert_to_integral(_Fp __val) { return __val; }
4234
4235#ifndef _LIBCPP_HAS_NO_INT128
4236inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4237__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4238
4239inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4240__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4241#endif
4242
4243template <class _Tp>
4244inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4245typename __sfinae_underlying_type<_Tp>::__promoted_type
4246__convert_to_integral(_Tp __val) { return __val; }
4247
4248#ifndef _LIBCPP_CXX03_LANG
4249
4250template <class _Tp>
4251struct __has_operator_addressof_member_imp
4252{
4253    template <class _Up>
4254        static auto __test(int)
4255            -> typename __select_2nd<decltype(_VSTD::declval<_Up>().operator&()), true_type>::type;
4256    template <class>
4257        static auto __test(long) -> false_type;
4258
4259    static const bool value = decltype(__test<_Tp>(0))::value;
4260};
4261
4262template <class _Tp>
4263struct __has_operator_addressof_free_imp
4264{
4265    template <class _Up>
4266        static auto __test(int)
4267            -> typename __select_2nd<decltype(operator&(_VSTD::declval<_Up>())), true_type>::type;
4268    template <class>
4269        static auto __test(long) -> false_type;
4270
4271    static const bool value = decltype(__test<_Tp>(0))::value;
4272};
4273
4274template <class _Tp>
4275struct __has_operator_addressof
4276    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
4277                                  || __has_operator_addressof_free_imp<_Tp>::value>
4278{};
4279
4280#endif  // _LIBCPP_CXX03_LANG
4281
4282#if _LIBCPP_STD_VER > 14
4283
4284template <class...> using void_t = void;
4285
4286template <class... _Args>
4287struct conjunction : _And<_Args...> {};
4288template<class... _Args>
4289_LIBCPP_INLINE_VAR constexpr bool conjunction_v
4290    = conjunction<_Args...>::value;
4291
4292template <class... _Args>
4293struct disjunction : _Or<_Args...> {};
4294template<class... _Args>
4295_LIBCPP_INLINE_VAR constexpr bool disjunction_v
4296    = disjunction<_Args...>::value;
4297
4298template <class _Tp>
4299struct negation : _Not<_Tp> {};
4300template<class _Tp>
4301_LIBCPP_INLINE_VAR constexpr bool negation_v
4302    = negation<_Tp>::value;
4303#endif  // _LIBCPP_STD_VER > 14
4304
4305// These traits are used in __tree and __hash_table
4306#ifndef _LIBCPP_CXX03_LANG
4307struct __extract_key_fail_tag {};
4308struct __extract_key_self_tag {};
4309struct __extract_key_first_tag {};
4310
4311template <class _ValTy, class _Key,
4312          class _RawValTy = typename __unconstref<_ValTy>::type>
4313struct __can_extract_key
4314    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4315                  __extract_key_fail_tag>::type {};
4316
4317template <class _Pair, class _Key, class _First, class _Second>
4318struct __can_extract_key<_Pair, _Key, pair<_First, _Second>>
4319    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4320                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4321
4322// __can_extract_map_key uses true_type/false_type instead of the tags.
4323// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4324// and _ValTy == _Key.
4325template <class _ValTy, class _Key, class _ContainerValueTy,
4326          class _RawValTy = typename __unconstref<_ValTy>::type>
4327struct __can_extract_map_key
4328    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4329
4330// This specialization returns __extract_key_fail_tag for non-map containers
4331// because _Key == _ContainerValueTy
4332template <class _ValTy, class _Key, class _RawValTy>
4333struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4334    : false_type {};
4335
4336#endif
4337
4338#ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
4339#if _LIBCPP_STD_VER > 17
4340_LIBCPP_INLINE_VISIBILITY
4341inline constexpr bool is_constant_evaluated() noexcept {
4342  return __builtin_is_constant_evaluated();
4343}
4344#endif
4345
4346inline _LIBCPP_CONSTEXPR
4347bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4348#else
4349inline _LIBCPP_CONSTEXPR
4350bool __libcpp_is_constant_evaluated() _NOEXCEPT { return false; }
4351#endif
4352
4353template <class _CharT>
4354using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4355
4356_LIBCPP_END_NAMESPACE_STD
4357
4358#if _LIBCPP_STD_VER > 14
4359// std::byte
4360namespace std  // purposefully not versioned
4361{
4362
4363
4364}
4365#endif
4366
4367#endif  // _LIBCPP_TYPE_TRAITS
4368