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_scoped_enum; // C++2b
55    template <class T> struct is_scalar;
56    template <class T> struct is_object;
57    template <class T> struct is_compound;
58
59    // Const-volatile properties and transformations:
60    template <class T> struct is_const;
61    template <class T> struct is_volatile;
62    template <class T> struct remove_const;
63    template <class T> struct remove_volatile;
64    template <class T> struct remove_cv;
65    template <class T> struct add_const;
66    template <class T> struct add_volatile;
67    template <class T> struct add_cv;
68
69    // Reference transformations:
70    template <class T> struct remove_reference;
71    template <class T> struct add_lvalue_reference;
72    template <class T> struct add_rvalue_reference;
73
74    // Pointer transformations:
75    template <class T> struct remove_pointer;
76    template <class T> struct add_pointer;
77
78    template<class T> struct type_identity;                     // C++20
79    template<class T>
80      using type_identity_t = typename type_identity<T>::type;  // C++20
81
82    // Integral properties:
83    template <class T> struct is_signed;
84    template <class T> struct is_unsigned;
85    template <class T> struct make_signed;
86    template <class T> struct make_unsigned;
87
88    // Array properties and transformations:
89    template <class T> struct rank;
90    template <class T, unsigned I = 0> struct extent;
91    template <class T> struct remove_extent;
92    template <class T> struct remove_all_extents;
93
94    template <class T> struct is_bounded_array;                 // C++20
95    template <class T> struct is_unbounded_array;               // C++20
96
97    // Member introspection:
98    template <class T> struct is_pod;
99    template <class T> struct is_trivial;
100    template <class T> struct is_trivially_copyable;
101    template <class T> struct is_standard_layout;
102    template <class T> struct is_literal_type;
103    template <class T> struct is_empty;
104    template <class T> struct is_polymorphic;
105    template <class T> struct is_abstract;
106    template <class T> struct is_final; // C++14
107    template <class T> struct is_aggregate; // C++17
108
109    template <class T, class... Args> struct is_constructible;
110    template <class T>                struct is_default_constructible;
111    template <class T>                struct is_copy_constructible;
112    template <class T>                struct is_move_constructible;
113    template <class T, class U>       struct is_assignable;
114    template <class T>                struct is_copy_assignable;
115    template <class T>                struct is_move_assignable;
116    template <class T, class U>       struct is_swappable_with;       // C++17
117    template <class T>                struct is_swappable;            // C++17
118    template <class T>                struct is_destructible;
119
120    template <class T, class... Args> struct is_trivially_constructible;
121    template <class T>                struct is_trivially_default_constructible;
122    template <class T>                struct is_trivially_copy_constructible;
123    template <class T>                struct is_trivially_move_constructible;
124    template <class T, class U>       struct is_trivially_assignable;
125    template <class T>                struct is_trivially_copy_assignable;
126    template <class T>                struct is_trivially_move_assignable;
127    template <class T>                struct is_trivially_destructible;
128
129    template <class T, class... Args> struct is_nothrow_constructible;
130    template <class T>                struct is_nothrow_default_constructible;
131    template <class T>                struct is_nothrow_copy_constructible;
132    template <class T>                struct is_nothrow_move_constructible;
133    template <class T, class U>       struct is_nothrow_assignable;
134    template <class T>                struct is_nothrow_copy_assignable;
135    template <class T>                struct is_nothrow_move_assignable;
136    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
137    template <class T>                struct is_nothrow_swappable;      // C++17
138    template <class T>                struct is_nothrow_destructible;
139
140    template <class T> struct has_virtual_destructor;
141
142    template<class T> struct has_unique_object_representations;         // C++17
143
144    // Relationships between types:
145    template <class T, class U> struct is_same;
146    template <class Base, class Derived> struct is_base_of;
147
148    template <class From, class To> struct is_convertible;
149    template <typename From, typename To> struct is_nothrow_convertible;                  // C++20
150    template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
151
152    template <class Fn, class... ArgTypes> struct is_invocable;
153    template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
154
155    template <class Fn, class... ArgTypes> struct is_nothrow_invocable;
156    template <class R, class Fn, class... ArgTypes> struct is_nothrow_invocable_r;
157
158    // Alignment properties and transformations:
159    template <class T> struct alignment_of;
160    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
161        struct aligned_storage;
162    template <size_t Len, class... Types> struct aligned_union;
163    template <class T> struct remove_cvref; // C++20
164
165    template <class T> struct decay;
166    template <class... T> struct common_type;
167    template <class T> struct underlying_type;
168    template <class> class result_of; // undefined
169    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>;
170    template <class Fn, class... ArgTypes> struct invoke_result;  // C++17
171
172    // const-volatile modifications:
173    template <class T>
174      using remove_const_t    = typename remove_const<T>::type;  // C++14
175    template <class T>
176      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
177    template <class T>
178      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
179    template <class T>
180      using add_const_t       = typename add_const<T>::type;  // C++14
181    template <class T>
182      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
183    template <class T>
184      using add_cv_t          = typename add_cv<T>::type;  // C++14
185
186    // reference modifications:
187    template <class T>
188      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
189    template <class T>
190      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
191    template <class T>
192      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
193
194    // sign modifications:
195    template <class T>
196      using make_signed_t   = typename make_signed<T>::type;  // C++14
197    template <class T>
198      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
199
200    // array modifications:
201    template <class T>
202      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
203    template <class T>
204      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
205
206    template <class T>
207      inline constexpr bool is_bounded_array_v
208        = is_bounded_array<T>::value;                                     // C++20
209      inline constexpr bool is_unbounded_array_v
210        = is_unbounded_array<T>::value;                                   // C++20
211
212    // pointer modifications:
213    template <class T>
214      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
215    template <class T>
216      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
217
218    // other transformations:
219    template <size_t Len, std::size_t Align=default-alignment>
220      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
221    template <std::size_t Len, class... Types>
222      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
223    template <class T>
224      using remove_cvref_t    = typename remove_cvref<T>::type;  // C++20
225    template <class T>
226      using decay_t           = typename decay<T>::type;  // C++14
227    template <bool b, class T=void>
228      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
229    template <bool b, class T, class F>
230      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
231    template <class... T>
232      using common_type_t     = typename common_type<T...>::type;  // C++14
233    template <class T>
234      using underlying_type_t = typename underlying_type<T>::type;  // C++14
235    template <class T>
236      using result_of_t       = typename result_of<T>::type;  // C++14
237    template <class Fn, class... ArgTypes>
238      using invoke_result_t   = typename invoke_result<Fn, ArgTypes...>::type;  // C++17
239
240    template <class...>
241      using void_t = void;   // C++17
242
243      // See C++14 20.10.4.1, primary type categories
244      template <class T> inline constexpr bool is_void_v
245        = is_void<T>::value;                                             // C++17
246      template <class T> inline constexpr bool is_null_pointer_v
247        = is_null_pointer<T>::value;                                     // C++17
248      template <class T> inline constexpr bool is_integral_v
249        = is_integral<T>::value;                                         // C++17
250      template <class T> inline constexpr bool is_floating_point_v
251        = is_floating_point<T>::value;                                   // C++17
252      template <class T> inline constexpr bool is_array_v
253        = is_array<T>::value;                                            // C++17
254      template <class T> inline constexpr bool is_pointer_v
255        = is_pointer<T>::value;                                          // C++17
256      template <class T> inline constexpr bool is_lvalue_reference_v
257        = is_lvalue_reference<T>::value;                                 // C++17
258      template <class T> inline constexpr bool is_rvalue_reference_v
259        = is_rvalue_reference<T>::value;                                 // C++17
260      template <class T> inline constexpr bool is_member_object_pointer_v
261        = is_member_object_pointer<T>::value;                            // C++17
262      template <class T> inline constexpr bool is_member_function_pointer_v
263        = is_member_function_pointer<T>::value;                          // C++17
264      template <class T> inline constexpr bool is_enum_v
265        = is_enum<T>::value;                                             // C++17
266      template <class T> inline constexpr bool is_union_v
267        = is_union<T>::value;                                            // C++17
268      template <class T> inline constexpr bool is_class_v
269        = is_class<T>::value;                                            // C++17
270      template <class T> inline constexpr bool is_function_v
271        = is_function<T>::value;                                         // C++17
272
273      // See C++14 20.10.4.2, composite type categories
274      template <class T> inline constexpr bool is_reference_v
275        = is_reference<T>::value;                                        // C++17
276      template <class T> inline constexpr bool is_arithmetic_v
277        = is_arithmetic<T>::value;                                       // C++17
278      template <class T> inline constexpr bool is_fundamental_v
279        = is_fundamental<T>::value;                                      // C++17
280      template <class T> inline constexpr bool is_object_v
281        = is_object<T>::value;                                           // C++17
282      template <class T> inline constexpr bool is_scalar_v
283        = is_scalar<T>::value;                                           // C++17
284      template <class T> inline constexpr bool is_compound_v
285        = is_compound<T>::value;                                         // C++17
286      template <class T> inline constexpr bool is_member_pointer_v
287        = is_member_pointer<T>::value;                                   // C++17
288      template <class T> inline constexpr bool is_scoped_enum_v
289        = is_scoped_enum<T>::value;                                      // C++2b
290
291      // See C++14 20.10.4.3, type properties
292      template <class T> inline constexpr bool is_const_v
293        = is_const<T>::value;                                            // C++17
294      template <class T> inline constexpr bool is_volatile_v
295        = is_volatile<T>::value;                                         // C++17
296      template <class T> inline constexpr bool is_trivial_v
297        = is_trivial<T>::value;                                          // C++17
298      template <class T> inline constexpr bool is_trivially_copyable_v
299        = is_trivially_copyable<T>::value;                               // C++17
300      template <class T> inline constexpr bool is_standard_layout_v
301        = is_standard_layout<T>::value;                                  // C++17
302      template <class T> inline constexpr bool is_pod_v
303        = is_pod<T>::value;                                              // C++17
304      template <class T> inline constexpr bool is_literal_type_v
305        = is_literal_type<T>::value;                                     // C++17
306      template <class T> inline constexpr bool is_empty_v
307        = is_empty<T>::value;                                            // C++17
308      template <class T> inline constexpr bool is_polymorphic_v
309        = is_polymorphic<T>::value;                                      // C++17
310      template <class T> inline constexpr bool is_abstract_v
311        = is_abstract<T>::value;                                         // C++17
312      template <class T> inline constexpr bool is_final_v
313        = is_final<T>::value;                                            // C++17
314      template <class T> inline constexpr bool is_aggregate_v
315        = is_aggregate<T>::value;                                        // C++17
316      template <class T> inline constexpr bool is_signed_v
317        = is_signed<T>::value;                                           // C++17
318      template <class T> inline constexpr bool is_unsigned_v
319        = is_unsigned<T>::value;                                         // C++17
320      template <class T, class... Args> inline constexpr bool is_constructible_v
321        = is_constructible<T, Args...>::value;                           // C++17
322      template <class T> inline constexpr bool is_default_constructible_v
323        = is_default_constructible<T>::value;                            // C++17
324      template <class T> inline constexpr bool is_copy_constructible_v
325        = is_copy_constructible<T>::value;                               // C++17
326      template <class T> inline constexpr bool is_move_constructible_v
327        = is_move_constructible<T>::value;                               // C++17
328      template <class T, class U> inline constexpr bool is_assignable_v
329        = is_assignable<T, U>::value;                                    // C++17
330      template <class T> inline constexpr bool is_copy_assignable_v
331        = is_copy_assignable<T>::value;                                  // C++17
332      template <class T> inline constexpr bool is_move_assignable_v
333        = is_move_assignable<T>::value;                                  // C++17
334      template <class T, class U> inline constexpr bool is_swappable_with_v
335        = is_swappable_with<T, U>::value;                                // C++17
336      template <class T> inline constexpr bool is_swappable_v
337        = is_swappable<T>::value;                                        // C++17
338      template <class T> inline constexpr bool is_destructible_v
339        = is_destructible<T>::value;                                     // C++17
340      template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
341        = is_trivially_constructible<T, Args...>::value;                 // C++17
342      template <class T> inline constexpr bool is_trivially_default_constructible_v
343        = is_trivially_default_constructible<T>::value;                  // C++17
344      template <class T> inline constexpr bool is_trivially_copy_constructible_v
345        = is_trivially_copy_constructible<T>::value;                     // C++17
346      template <class T> inline constexpr bool is_trivially_move_constructible_v
347        = is_trivially_move_constructible<T>::value;                     // C++17
348      template <class T, class U> inline constexpr bool is_trivially_assignable_v
349        = is_trivially_assignable<T, U>::value;                          // C++17
350      template <class T> inline constexpr bool is_trivially_copy_assignable_v
351        = is_trivially_copy_assignable<T>::value;                        // C++17
352      template <class T> inline constexpr bool is_trivially_move_assignable_v
353        = is_trivially_move_assignable<T>::value;                        // C++17
354      template <class T> inline constexpr bool is_trivially_destructible_v
355        = is_trivially_destructible<T>::value;                           // C++17
356      template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
357        = is_nothrow_constructible<T, Args...>::value;                   // C++17
358      template <class T> inline constexpr bool is_nothrow_default_constructible_v
359        = is_nothrow_default_constructible<T>::value;                    // C++17
360      template <class T> inline constexpr bool is_nothrow_copy_constructible_v
361        = is_nothrow_copy_constructible<T>::value;                       // C++17
362      template <class T> inline constexpr bool is_nothrow_move_constructible_v
363        = is_nothrow_move_constructible<T>::value;                       // C++17
364      template <class T, class U> inline constexpr bool is_nothrow_assignable_v
365        = is_nothrow_assignable<T, U>::value;                            // C++17
366      template <class T> inline constexpr bool is_nothrow_copy_assignable_v
367        = is_nothrow_copy_assignable<T>::value;                          // C++17
368      template <class T> inline constexpr bool is_nothrow_move_assignable_v
369        = is_nothrow_move_assignable<T>::value;                          // C++17
370      template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
371        = is_nothrow_swappable_with<T, U>::value;                       // C++17
372      template <class T> inline constexpr bool is_nothrow_swappable_v
373        = is_nothrow_swappable<T>::value;                               // C++17
374      template <class T> inline constexpr bool is_nothrow_destructible_v
375        = is_nothrow_destructible<T>::value;                             // C++17
376      template <class T> inline constexpr bool has_virtual_destructor_v
377        = has_virtual_destructor<T>::value;                              // C++17
378      template<class T> inline constexpr bool has_unique_object_representations_v // C++17
379        = has_unique_object_representations<T>::value;
380
381      // See C++14 20.10.5, type property queries
382      template <class T> inline constexpr size_t alignment_of_v
383        = alignment_of<T>::value;                                        // C++17
384      template <class T> inline constexpr size_t rank_v
385        = rank<T>::value;                                                // C++17
386      template <class T, unsigned I = 0> inline constexpr size_t extent_v
387        = extent<T, I>::value;                                           // C++17
388
389      // See C++14 20.10.6, type relations
390      template <class T, class U> inline constexpr bool is_same_v
391        = is_same<T, U>::value;                                          // C++17
392      template <class Base, class Derived> inline constexpr bool is_base_of_v
393        = is_base_of<Base, Derived>::value;                              // C++17
394      template <class From, class To> inline constexpr bool is_convertible_v
395        = is_convertible<From, To>::value;                               // C++17
396      template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
397        = is_invocable<Fn, ArgTypes...>::value;                          // C++17
398      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
399        = is_invocable_r<R, Fn, ArgTypes...>::value;                     // C++17
400      template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
401        = is_nothrow_invocable<Fn, ArgTypes...>::value;                  // C++17
402      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
403        = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value;             // C++17
404
405      // [meta.logical], logical operator traits:
406      template<class... B> struct conjunction;                           // C++17
407      template<class... B>
408        inline constexpr bool conjunction_v = conjunction<B...>::value;  // C++17
409      template<class... B> struct disjunction;                           // C++17
410      template<class... B>
411        inline constexpr bool disjunction_v = disjunction<B...>::value;  // C++17
412      template<class B> struct negation;                                 // C++17
413      template<class B>
414        inline constexpr bool negation_v = negation<B>::value;           // C++17
415
416}
417
418*/
419#include <__config>
420#include <cstddef>
421#include <version>
422
423#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
424#pragma GCC system_header
425#endif
426
427_LIBCPP_BEGIN_NAMESPACE_STD
428
429template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
430template <class _Tp> class _LIBCPP_TEMPLATE_VIS reference_wrapper;
431template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
432
433template <class _Tp, _Tp __v>
434struct _LIBCPP_TEMPLATE_VIS integral_constant
435{
436  static _LIBCPP_CONSTEXPR const _Tp      value = __v;
437  typedef _Tp               value_type;
438  typedef integral_constant type;
439  _LIBCPP_INLINE_VISIBILITY
440  _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
441#if _LIBCPP_STD_VER > 11
442  _LIBCPP_INLINE_VISIBILITY
443  constexpr value_type operator ()() const _NOEXCEPT {return value;}
444#endif
445};
446
447template <class _Tp, _Tp __v>
448_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
449
450#if _LIBCPP_STD_VER > 14
451template <bool __b>
452using bool_constant = integral_constant<bool, __b>;
453#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
454#else
455#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
456#endif
457
458typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
459typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
460
461template <bool _Val>
462using _BoolConstant _LIBCPP_NODEBUG_TYPE = integral_constant<bool, _Val>;
463
464template <bool> struct _MetaBase;
465template <>
466struct _MetaBase<true> {
467  template <class _Tp, class _Up>
468  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Tp;
469  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
470  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _FirstFn<_Args...>;
471  template <class _First, class...>
472  using _FirstImpl _LIBCPP_NODEBUG_TYPE = _First;
473  template <class, class _Second, class...>
474  using _SecondImpl _LIBCPP_NODEBUG_TYPE = _Second;
475  template <class _Tp = void>
476  using _EnableIfImpl _LIBCPP_NODEBUG_TYPE = _Tp;
477  template <class _Result, class _First, class ..._Rest>
478  using _OrImpl _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
479  template <class _Result, class _First, class ..._Rest>
480  using _AndImpl _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_First::value == true && sizeof...(_Rest) != 0>::template _AndImpl<_First, _Rest...>;
481};
482
483template <>
484struct _MetaBase<false> {
485  template <class _Tp, class _Up>
486  using _SelectImpl _LIBCPP_NODEBUG_TYPE = _Up;
487  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
488  using _SelectApplyImpl _LIBCPP_NODEBUG_TYPE = _SecondFn<_Args...>;
489  template <class _Result, class ...>
490  using _OrImpl _LIBCPP_NODEBUG_TYPE = _Result;
491  template <class _Result, class ...>
492  using _AndImpl _LIBCPP_NODEBUG_TYPE = _Result;
493};
494template <bool _Cond, class _Ret = void>
495using _EnableIf _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _EnableIfImpl<_Ret>;
496template <bool _Cond, class _IfRes, class _ElseRes>
497using _If _LIBCPP_NODEBUG_TYPE = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
498template <class ..._Rest>
499using _Or _LIBCPP_NODEBUG_TYPE = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
500template <class ..._Rest>
501using _And _LIBCPP_NODEBUG_TYPE = typename _MetaBase< sizeof...(_Rest) != 0 >::template _AndImpl<true_type, _Rest...>;
502template <class _Pred>
503struct _Not : _BoolConstant<!_Pred::value> {};
504template <class ..._Args>
505using _FirstType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
506template <class ..._Args>
507using _SecondType _LIBCPP_NODEBUG_TYPE = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
508
509template <template <class...> class _Func, class ..._Args>
510struct _Lazy : _Func<_Args...> {};
511
512// Member detector base
513
514template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
515true_type __sfinae_test_impl(int);
516template <template <class...> class, class ...>
517false_type __sfinae_test_impl(...);
518
519template <template <class ...> class _Templ, class ..._Args>
520using _IsValidExpansion _LIBCPP_NODEBUG_TYPE = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
521
522template <class>
523struct __void_t { typedef void type; };
524
525template <class _Tp>
526struct __identity { typedef _Tp type; };
527
528template <class _Tp, bool>
529struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
530
531
532template <bool _Bp, class _If, class _Then>
533    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
534template <class _If, class _Then>
535    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
536
537#if _LIBCPP_STD_VER > 11
538template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
539#endif
540
541template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
542template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
543
544#if _LIBCPP_STD_VER > 11
545template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
546#endif
547
548// is_same
549
550#if __has_keyword(__is_same)
551
552template <class _Tp, class _Up>
553struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
554
555#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
556template <class _Tp, class _Up>
557_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v = __is_same(_Tp, _Up);
558#endif
559
560#else
561
562template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
563template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
564
565#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
566template <class _Tp, class _Up>
567_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_same_v
568    = is_same<_Tp, _Up>::value;
569#endif
570
571#endif // __is_same
572
573template <class _Tp, class _Up>
574using _IsSame = _BoolConstant<
575#ifdef __clang__
576    __is_same(_Tp, _Up)
577#else
578    _VSTD::is_same<_Tp, _Up>::value
579#endif
580>;
581
582template <class _Tp, class _Up>
583using _IsNotSame = _BoolConstant<
584#ifdef __clang__
585    !__is_same(_Tp, _Up)
586#else
587    !_VSTD::is_same<_Tp, _Up>::value
588#endif
589>;
590
591
592template <class _Tp>
593using __test_for_primary_template = _EnableIf<
594    _IsSame<_Tp, typename _Tp::__primary_template>::value
595  >;
596template <class _Tp>
597using __is_primary_template = _IsValidExpansion<
598    __test_for_primary_template, _Tp
599  >;
600
601struct __two {char __lx[2];};
602
603// helper class:
604
605// is_const
606
607#if __has_keyword(__is_const)
608
609template <class _Tp>
610struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
611
612#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
613template <class _Tp>
614_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v = __is_const(_Tp);
615#endif
616
617#else
618
619template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
620template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
621
622#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
623template <class _Tp>
624_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_const_v
625    = is_const<_Tp>::value;
626#endif
627
628#endif // __has_keyword(__is_const)
629
630// is_volatile
631
632#if __has_keyword(__is_volatile)
633
634template <class _Tp>
635struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
636
637#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
638template <class _Tp>
639_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v = __is_volatile(_Tp);
640#endif
641
642#else
643
644template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
645template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
646
647#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
648template <class _Tp>
649_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_volatile_v
650    = is_volatile<_Tp>::value;
651#endif
652
653#endif // __has_keyword(__is_volatile)
654
655// remove_const
656
657#if __has_keyword(__remove_const)
658
659template <class _Tp>
660struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
661
662#if _LIBCPP_STD_VER > 11
663template <class _Tp> using remove_const_t = __remove_const(_Tp);
664#endif
665
666#else
667
668template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
669template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
670#if _LIBCPP_STD_VER > 11
671template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
672#endif
673
674#endif // __has_keyword(__remove_const)
675
676// remove_volatile
677
678#if __has_keyword(__remove_volatile)
679
680template <class _Tp>
681struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
682
683#if _LIBCPP_STD_VER > 11
684template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
685#endif
686
687#else
688
689template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
690template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
691#if _LIBCPP_STD_VER > 11
692template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
693#endif
694
695#endif // __has_keyword(__remove_volatile)
696
697// remove_cv
698
699#if __has_keyword(__remove_cv)
700
701template <class _Tp>
702struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
703
704#if _LIBCPP_STD_VER > 11
705template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
706#endif
707
708#else
709
710template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
711{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
712#if _LIBCPP_STD_VER > 11
713template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
714#endif
715
716#endif // __has_keyword(__remove_cv)
717
718// is_void
719
720#if __has_keyword(__is_void)
721
722template <class _Tp>
723struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
724
725#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
726template <class _Tp>
727_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v = __is_void(_Tp);
728#endif
729
730#else
731
732template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
733    : public is_same<typename remove_cv<_Tp>::type, void> {};
734
735#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
736template <class _Tp>
737_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_void_v
738    = is_void<_Tp>::value;
739#endif
740
741#endif // __has_keyword(__is_void)
742
743// __is_nullptr_t
744
745template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
746template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
747
748template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
749    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
750
751#if _LIBCPP_STD_VER > 11
752template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
753    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
754
755#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
756template <class _Tp>
757_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_null_pointer_v
758    = is_null_pointer<_Tp>::value;
759#endif
760#endif // _LIBCPP_STD_VER > 11
761
762// is_integral
763
764#if __has_keyword(__is_integral)
765
766template <class _Tp>
767struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
768
769#if _LIBCPP_STD_VER > 14
770template <class _Tp>
771_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v = __is_integral(_Tp);
772#endif
773
774#else
775
776template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
777    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
778
779#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
780template <class _Tp>
781_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_integral_v
782    = is_integral<_Tp>::value;
783#endif
784
785#endif // __has_keyword(__is_integral)
786
787// is_floating_point
788
789template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
790template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
791template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
792template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
793
794template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
795    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
796
797#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
798template <class _Tp>
799_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_floating_point_v
800    = is_floating_point<_Tp>::value;
801#endif
802
803// is_array
804
805#if __has_keyword(__is_array)
806
807template <class _Tp>
808struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
809
810#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
811template <class _Tp>
812_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v = __is_array(_Tp);
813#endif
814
815#else
816
817template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
818    : public false_type {};
819template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
820    : public true_type {};
821template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
822    : public true_type {};
823
824#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
825template <class _Tp>
826_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v
827    = is_array<_Tp>::value;
828#endif
829
830#endif // __has_keyword(__is_array)
831
832// is_pointer
833
834// In clang 10.0.0 and earlier __is_pointer didn't work with Objective-C types.
835#if __has_keyword(__is_pointer) && _LIBCPP_CLANG_VER > 1000
836
837template<class _Tp>
838struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
839
840#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
841template <class _Tp>
842_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v = __is_pointer(_Tp);
843#endif
844
845#else // __has_keyword(__is_pointer)
846
847template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
848template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
849
850template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
851#if defined(_LIBCPP_HAS_OBJC_ARC)
852template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
853template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
854template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
855template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
856#endif
857
858template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
859    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
860
861#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
862template <class _Tp>
863_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pointer_v
864    = is_pointer<_Tp>::value;
865#endif
866
867#endif // __has_keyword(__is_pointer)
868
869// is_reference
870
871#if __has_keyword(__is_lvalue_reference) && \
872    __has_keyword(__is_rvalue_reference) && \
873    __has_keyword(__is_reference)
874
875template<class _Tp>
876struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
877
878template<class _Tp>
879struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
880
881template<class _Tp>
882struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
883
884#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
885template <class _Tp>
886_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v = __is_reference(_Tp);
887
888template <class _Tp>
889_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
890
891template <class _Tp>
892_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
893#endif
894
895#else // __has_keyword(__is_lvalue_reference) && etc...
896
897template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
898template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
899
900template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
901template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
902
903template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
904template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
905template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
906
907#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
908template <class _Tp>
909_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_reference_v
910    = is_reference<_Tp>::value;
911
912template <class _Tp>
913_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_lvalue_reference_v
914    = is_lvalue_reference<_Tp>::value;
915
916template <class _Tp>
917_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_rvalue_reference_v
918    = is_rvalue_reference<_Tp>::value;
919#endif
920
921#endif // __has_keyword(__is_lvalue_reference) && etc...
922
923// is_union
924
925#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
926
927template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
928    : public integral_constant<bool, __is_union(_Tp)> {};
929
930#else
931
932template <class _Tp> struct __libcpp_union : public false_type {};
933template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
934    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
935
936#endif
937
938#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
939template <class _Tp>
940_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_union_v
941    = is_union<_Tp>::value;
942#endif
943
944// is_class
945
946#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
947
948template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
949    : public integral_constant<bool, __is_class(_Tp)> {};
950
951#else
952
953namespace __is_class_imp
954{
955template <class _Tp> char  __test(int _Tp::*);
956template <class _Tp> __two __test(...);
957}
958
959template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
960    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
961
962#endif
963
964#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
965template <class _Tp>
966_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_class_v
967    = is_class<_Tp>::value;
968#endif
969
970// is_function
971
972template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
973    : public _BoolConstant<
974#ifdef __clang__
975    __is_function(_Tp)
976#else
977 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
978#endif
979    > {};
980
981
982#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
983template <class _Tp>
984_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_function_v
985    = is_function<_Tp>::value;
986#endif
987
988template <class _Tp> struct __libcpp_is_member_pointer {
989  enum {
990    __is_member = false,
991    __is_func = false,
992    __is_obj = false
993  };
994};
995template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
996  enum {
997    __is_member = true,
998    __is_func = is_function<_Tp>::value,
999    __is_obj = !__is_func,
1000  };
1001};
1002
1003#if __has_keyword(__is_member_function_pointer)
1004
1005template<class _Tp>
1006struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1007    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1008
1009#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1010template <class _Tp>
1011_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1012    = __is_member_function_pointer(_Tp);
1013#endif
1014
1015#else // __has_keyword(__is_member_function_pointer)
1016
1017template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1018    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1019
1020#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1021template <class _Tp>
1022_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
1023    = is_member_function_pointer<_Tp>::value;
1024#endif
1025
1026#endif // __has_keyword(__is_member_function_pointer)
1027
1028// is_member_pointer
1029
1030#if __has_keyword(__is_member_pointer)
1031
1032template<class _Tp>
1033struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
1034
1035#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1036template <class _Tp>
1037_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v = __is_member_pointer(_Tp);
1038#endif
1039
1040#else // __has_keyword(__is_member_pointer)
1041
1042template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1043 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1044
1045#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1046template <class _Tp>
1047_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_pointer_v
1048    = is_member_pointer<_Tp>::value;
1049#endif
1050
1051#endif // __has_keyword(__is_member_pointer)
1052
1053// is_member_object_pointer
1054
1055#if __has_keyword(__is_member_object_pointer)
1056
1057template<class _Tp>
1058struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1059    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1060
1061#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1062template <class _Tp>
1063_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1064    = __is_member_object_pointer(_Tp);
1065#endif
1066
1067#else // __has_keyword(__is_member_object_pointer)
1068
1069template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1070    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1071
1072#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1073template <class _Tp>
1074_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
1075    = is_member_object_pointer<_Tp>::value;
1076#endif
1077
1078#endif // __has_keyword(__is_member_object_pointer)
1079
1080// is_enum
1081
1082#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1083
1084template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1085    : public integral_constant<bool, __is_enum(_Tp)> {};
1086
1087#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1088template <class _Tp>
1089_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v = __is_enum(_Tp);
1090#endif
1091
1092#else
1093
1094template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1095    : public integral_constant<bool, !is_void<_Tp>::value             &&
1096                                     !is_integral<_Tp>::value         &&
1097                                     !is_floating_point<_Tp>::value   &&
1098                                     !is_array<_Tp>::value            &&
1099                                     !is_pointer<_Tp>::value          &&
1100                                     !is_reference<_Tp>::value        &&
1101                                     !is_member_pointer<_Tp>::value   &&
1102                                     !is_union<_Tp>::value            &&
1103                                     !is_class<_Tp>::value            &&
1104                                     !is_function<_Tp>::value         > {};
1105
1106#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1107template <class _Tp>
1108_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_enum_v
1109    = is_enum<_Tp>::value;
1110#endif
1111
1112#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1113
1114// is_arithmetic
1115
1116
1117template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1118    : public integral_constant<bool, is_integral<_Tp>::value      ||
1119                                     is_floating_point<_Tp>::value> {};
1120
1121#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1122template <class _Tp>
1123_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_arithmetic_v
1124    = is_arithmetic<_Tp>::value;
1125#endif
1126
1127// is_fundamental
1128
1129// In clang 9 and lower, this builtin did not work for nullptr_t. Additionally, in C++03 mode,
1130// nullptr isn't defined by the compiler so, this builtin won't work.
1131#if __has_keyword(__is_fundamental) && _LIBCPP_CLANG_VER > 900 && !defined(_LIBCPP_CXX03_LANG)
1132
1133template<class _Tp>
1134struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1135
1136#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1137template <class _Tp>
1138_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v = __is_fundamental(_Tp);
1139#endif
1140
1141#else // __has_keyword(__is_fundamental)
1142
1143template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1144    : public integral_constant<bool, is_void<_Tp>::value        ||
1145                                     __is_nullptr_t<_Tp>::value ||
1146                                     is_arithmetic<_Tp>::value> {};
1147
1148#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1149template <class _Tp>
1150_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_fundamental_v
1151    = is_fundamental<_Tp>::value;
1152#endif
1153
1154#endif // __has_keyword(__is_fundamental)
1155
1156// is_scalar
1157
1158// >= 11 because in C++03 nullptr isn't actually nullptr
1159#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1160
1161template<class _Tp>
1162struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1163
1164#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1165template <class _Tp>
1166_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v = __is_scalar(_Tp);
1167#endif
1168
1169#else // __has_keyword(__is_scalar)
1170
1171template <class _Tp> struct __is_block : false_type {};
1172#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1173template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1174#endif
1175
1176template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1177    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1178                                     is_member_pointer<_Tp>::value ||
1179                                     is_pointer<_Tp>::value        ||
1180                                     __is_nullptr_t<_Tp>::value    ||
1181                                     __is_block<_Tp>::value        ||
1182                                     is_enum<_Tp>::value           > {};
1183
1184template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1185
1186#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1187template <class _Tp>
1188_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scalar_v
1189    = is_scalar<_Tp>::value;
1190#endif
1191
1192#endif // __has_keyword(__is_scalar)
1193
1194// is_object
1195
1196#if __has_keyword(__is_object)
1197
1198template<class _Tp>
1199struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1200
1201#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1202template <class _Tp>
1203_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v = __is_object(_Tp);
1204#endif
1205
1206#else // __has_keyword(__is_object)
1207
1208template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1209    : public integral_constant<bool, is_scalar<_Tp>::value ||
1210                                     is_array<_Tp>::value  ||
1211                                     is_union<_Tp>::value  ||
1212                                     is_class<_Tp>::value  > {};
1213
1214#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1215template <class _Tp>
1216_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_object_v
1217    = is_object<_Tp>::value;
1218#endif
1219
1220#endif // __has_keyword(__is_object)
1221
1222// is_compound
1223
1224// >= 11 because in C++03 nullptr isn't actually nullptr
1225#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1226
1227template<class _Tp>
1228struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1229
1230#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1231template <class _Tp>
1232_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v = __is_compound(_Tp);
1233#endif
1234
1235#else // __has_keyword(__is_compound)
1236
1237template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1238    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1239
1240#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1241template <class _Tp>
1242_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_compound_v
1243    = is_compound<_Tp>::value;
1244#endif
1245
1246#endif // __has_keyword(__is_compound)
1247
1248// __is_referenceable  [defns.referenceable]
1249
1250struct __is_referenceable_impl {
1251    template <class _Tp> static _Tp& __test(int);
1252    template <class _Tp> static __two __test(...);
1253};
1254
1255template <class _Tp>
1256struct __is_referenceable : integral_constant<bool,
1257    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1258
1259
1260// add_const
1261
1262template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1263  typedef _LIBCPP_NODEBUG_TYPE const _Tp type;
1264};
1265
1266#if _LIBCPP_STD_VER > 11
1267template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1268#endif
1269
1270// add_volatile
1271
1272template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1273  typedef _LIBCPP_NODEBUG_TYPE volatile _Tp type;
1274};
1275
1276#if _LIBCPP_STD_VER > 11
1277template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1278#endif
1279
1280// add_cv
1281template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1282  typedef _LIBCPP_NODEBUG_TYPE const volatile _Tp type;
1283};
1284
1285#if _LIBCPP_STD_VER > 11
1286template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1287#endif
1288
1289// remove_reference
1290
1291#if __has_keyword(__remove_reference)
1292
1293template<class _Tp>
1294struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1295
1296#else // __has_keyword(__remove_reference)
1297
1298template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1299template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1300template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1301
1302#if _LIBCPP_STD_VER > 11
1303template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1304#endif
1305
1306#endif // __has_keyword(__remove_reference)
1307
1308// add_lvalue_reference
1309
1310template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE _Tp  type; };
1311template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
1312
1313template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1314{typedef _LIBCPP_NODEBUG_TYPE typename  __add_lvalue_reference_impl<_Tp>::type type;};
1315
1316#if _LIBCPP_STD_VER > 11
1317template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1318#endif
1319
1320template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG_TYPE  _Tp   type; };
1321template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG_TYPE  _Tp&& type; };
1322
1323template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1324{typedef _LIBCPP_NODEBUG_TYPE  typename __add_rvalue_reference_impl<_Tp>::type type;};
1325
1326#if _LIBCPP_STD_VER > 11
1327template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1328#endif
1329
1330// Suppress deprecation notice for volatile-qualified return type resulting
1331// from volatile-qualified types _Tp.
1332_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1333template <class _Tp> _Tp&& __declval(int);
1334template <class _Tp> _Tp   __declval(long);
1335_LIBCPP_SUPPRESS_DEPRECATED_POP
1336
1337template <class _Tp>
1338decltype(_VSTD::__declval<_Tp>(0))
1339declval() _NOEXCEPT;
1340
1341// __uncvref
1342
1343template <class _Tp>
1344struct __uncvref  {
1345    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1346};
1347
1348template <class _Tp>
1349struct __unconstref {
1350    typedef _LIBCPP_NODEBUG_TYPE typename remove_const<typename remove_reference<_Tp>::type>::type type;
1351};
1352
1353#ifndef _LIBCPP_CXX03_LANG
1354template <class _Tp>
1355using __uncvref_t _LIBCPP_NODEBUG_TYPE = typename __uncvref<_Tp>::type;
1356#endif
1357
1358// __is_same_uncvref
1359
1360template <class _Tp, class _Up>
1361struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1362                                   typename __uncvref<_Up>::type> {};
1363
1364#if _LIBCPP_STD_VER > 17
1365// remove_cvref - same as __uncvref
1366template <class _Tp>
1367struct remove_cvref : public __uncvref<_Tp> {};
1368
1369template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1370#endif
1371
1372
1373struct __any
1374{
1375    __any(...);
1376};
1377
1378// remove_pointer
1379
1380template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1381template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1382template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1383template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1384template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1385
1386#if _LIBCPP_STD_VER > 11
1387template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1388#endif
1389
1390// add_pointer
1391
1392template <class _Tp,
1393        bool = __is_referenceable<_Tp>::value ||
1394                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1395struct __add_pointer_impl
1396    {typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type* type;};
1397template <class _Tp> struct __add_pointer_impl<_Tp, false>
1398    {typedef _LIBCPP_NODEBUG_TYPE _Tp type;};
1399
1400template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1401    {typedef _LIBCPP_NODEBUG_TYPE typename __add_pointer_impl<_Tp>::type type;};
1402
1403#if _LIBCPP_STD_VER > 11
1404template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1405#endif
1406
1407// type_identity
1408#if _LIBCPP_STD_VER > 17
1409template<class _Tp> struct type_identity { typedef _Tp type; };
1410template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1411#endif
1412
1413// is_signed
1414
1415// In clang 9 and earlier, this builtin did not work for floating points or enums
1416#if __has_keyword(__is_signed) && _LIBCPP_CLANG_VER > 900
1417
1418template<class _Tp>
1419struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1420
1421#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1422template <class _Tp>
1423_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v = __is_signed(_Tp);
1424#endif
1425
1426#else // __has_keyword(__is_signed)
1427
1428template <class _Tp, bool = is_integral<_Tp>::value>
1429struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1430
1431template <class _Tp>
1432struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1433
1434template <class _Tp, bool = is_arithmetic<_Tp>::value>
1435struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1436
1437template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1438
1439template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1440
1441#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1442template <class _Tp>
1443_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v
1444    = is_signed<_Tp>::value;
1445#endif
1446
1447#endif // __has_keyword(__is_signed)
1448
1449// is_unsigned
1450
1451#if __has_keyword(__is_unsigned)
1452
1453template<class _Tp>
1454struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
1455
1456#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1457template <class _Tp>
1458_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v = __is_unsigned(_Tp);
1459#endif
1460
1461#else // __has_keyword(__is_unsigned)
1462
1463template <class _Tp, bool = is_integral<_Tp>::value>
1464struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1465
1466template <class _Tp>
1467struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1468
1469template <class _Tp, bool = is_arithmetic<_Tp>::value>
1470struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1471
1472template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1473
1474template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1475
1476#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1477template <class _Tp>
1478_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_unsigned_v
1479    = is_unsigned<_Tp>::value;
1480#endif
1481
1482#endif // __has_keyword(__is_unsigned)
1483
1484// rank
1485
1486template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1487    : public integral_constant<size_t, 0> {};
1488template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1489    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1490template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1491    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1492
1493#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1494template <class _Tp>
1495_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t rank_v
1496    = rank<_Tp>::value;
1497#endif
1498
1499// extent
1500
1501#if __has_keyword(__array_extent)
1502
1503template<class _Tp, size_t _Dim = 0>
1504struct _LIBCPP_TEMPLATE_VIS extent
1505    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1506
1507#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1508template <class _Tp, unsigned _Ip = 0>
1509_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v = __array_extent(_Tp, _Ip);
1510#endif
1511
1512#else // __has_keyword(__array_extent)
1513
1514template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1515    : public integral_constant<size_t, 0> {};
1516template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1517    : public integral_constant<size_t, 0> {};
1518template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1519    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1520template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1521    : public integral_constant<size_t, _Np> {};
1522template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1523    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1524
1525#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1526template <class _Tp, unsigned _Ip = 0>
1527_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t extent_v
1528    = extent<_Tp, _Ip>::value;
1529#endif
1530
1531#endif // __has_keyword(__array_extent)
1532
1533// remove_extent
1534
1535template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1536    {typedef _Tp type;};
1537template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1538    {typedef _Tp type;};
1539template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1540    {typedef _Tp type;};
1541
1542#if _LIBCPP_STD_VER > 11
1543template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1544#endif
1545
1546// remove_all_extents
1547
1548template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1549    {typedef _Tp type;};
1550template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1551    {typedef typename remove_all_extents<_Tp>::type type;};
1552template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1553    {typedef typename remove_all_extents<_Tp>::type type;};
1554
1555#if _LIBCPP_STD_VER > 11
1556template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1557#endif
1558
1559#if _LIBCPP_STD_VER > 17
1560// is_bounded_array
1561
1562template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1563template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1564
1565template <class _Tp>
1566_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1567bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1568
1569// is_unbounded_array
1570
1571template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1572template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1573
1574template <class _Tp>
1575_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
1576bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1577#endif
1578
1579// decay
1580
1581template <class _Up, bool>
1582struct __decay {
1583    typedef _LIBCPP_NODEBUG_TYPE typename remove_cv<_Up>::type type;
1584};
1585
1586template <class _Up>
1587struct __decay<_Up, true> {
1588public:
1589    typedef _LIBCPP_NODEBUG_TYPE typename conditional
1590                     <
1591                         is_array<_Up>::value,
1592                         typename remove_extent<_Up>::type*,
1593                         typename conditional
1594                         <
1595                              is_function<_Up>::value,
1596                              typename add_pointer<_Up>::type,
1597                              typename remove_cv<_Up>::type
1598                         >::type
1599                     >::type type;
1600};
1601
1602template <class _Tp>
1603struct _LIBCPP_TEMPLATE_VIS decay
1604{
1605private:
1606    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
1607public:
1608    typedef _LIBCPP_NODEBUG_TYPE typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1609};
1610
1611#if _LIBCPP_STD_VER > 11
1612template <class _Tp> using decay_t = typename decay<_Tp>::type;
1613#endif
1614
1615// is_abstract
1616
1617template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1618    : public integral_constant<bool, __is_abstract(_Tp)> {};
1619
1620#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1621template <class _Tp>
1622_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_abstract_v
1623    = is_abstract<_Tp>::value;
1624#endif
1625
1626// is_final
1627
1628template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1629__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1630
1631#if _LIBCPP_STD_VER > 11
1632template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1633is_final : public integral_constant<bool, __is_final(_Tp)> {};
1634#endif
1635
1636#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1637template <class _Tp>
1638_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_final_v
1639    = is_final<_Tp>::value;
1640#endif
1641
1642// is_aggregate
1643#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1644
1645template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1646is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1647
1648#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1649template <class _Tp>
1650_LIBCPP_INLINE_VAR constexpr bool is_aggregate_v
1651    = is_aggregate<_Tp>::value;
1652#endif
1653
1654#endif // _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_IS_AGGREGATE)
1655
1656// is_base_of
1657
1658template <class _Bp, class _Dp>
1659struct _LIBCPP_TEMPLATE_VIS is_base_of
1660    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1661
1662#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1663template <class _Bp, class _Dp>
1664_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_base_of_v
1665    = is_base_of<_Bp, _Dp>::value;
1666#endif
1667
1668// is_convertible
1669
1670#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1671
1672template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1673    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1674
1675#else  // __has_feature(is_convertible_to)
1676
1677namespace __is_convertible_imp
1678{
1679template <class _Tp> void  __test_convert(_Tp);
1680
1681template <class _From, class _To, class = void>
1682struct __is_convertible_test : public false_type {};
1683
1684template <class _From, class _To>
1685struct __is_convertible_test<_From, _To,
1686    decltype(_VSTD::__is_convertible_imp::__test_convert<_To>(_VSTD::declval<_From>()))> : public true_type
1687{};
1688
1689template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1690                     bool _IsFunction = is_function<_Tp>::value,
1691                     bool _IsVoid =     is_void<_Tp>::value>
1692                     struct __is_array_function_or_void                          {enum {value = 0};};
1693template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1694template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1695template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1696}
1697
1698template <class _Tp,
1699    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1700struct __is_convertible_check
1701{
1702    static const size_t __v = 0;
1703};
1704
1705template <class _Tp>
1706struct __is_convertible_check<_Tp, 0>
1707{
1708    static const size_t __v = sizeof(_Tp);
1709};
1710
1711template <class _T1, class _T2,
1712    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1713    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1714struct __is_convertible
1715    : public integral_constant<bool,
1716        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1717    >
1718{};
1719
1720template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1721template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1722template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1723template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1724
1725template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1726template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1727template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1728template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1729
1730template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1731template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1732template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1733template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1734
1735template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1736    : public __is_convertible<_T1, _T2>
1737{
1738    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1739    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1740};
1741
1742#endif  // __has_feature(is_convertible_to)
1743
1744#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1745template <class _From, class _To>
1746_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_convertible_v
1747    = is_convertible<_From, _To>::value;
1748#endif
1749
1750// is_nothrow_convertible
1751
1752#if _LIBCPP_STD_VER > 17
1753
1754template <typename _Tp>
1755static void __test_noexcept(_Tp) noexcept;
1756
1757template<typename _Fm, typename _To>
1758static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
1759__is_nothrow_convertible_test();
1760
1761template <typename _Fm, typename _To>
1762struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1763{ };
1764
1765template <typename _Fm, typename _To>
1766struct is_nothrow_convertible : _Or<
1767    _And<is_void<_To>, is_void<_Fm>>,
1768    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1769>::type { };
1770
1771template <typename _Fm, typename _To>
1772inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1773
1774#endif // _LIBCPP_STD_VER > 17
1775
1776// is_empty
1777
1778#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1779
1780template <class _Tp>
1781struct _LIBCPP_TEMPLATE_VIS is_empty
1782    : public integral_constant<bool, __is_empty(_Tp)> {};
1783
1784#else  // __has_feature(is_empty)
1785
1786template <class _Tp>
1787struct __is_empty1
1788    : public _Tp
1789{
1790    double __lx;
1791};
1792
1793struct __is_empty2
1794{
1795    double __lx;
1796};
1797
1798template <class _Tp, bool = is_class<_Tp>::value>
1799struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1800
1801template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1802
1803template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1804
1805#endif  // __has_feature(is_empty)
1806
1807#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1808template <class _Tp>
1809_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_empty_v
1810    = is_empty<_Tp>::value;
1811#endif
1812
1813// is_polymorphic
1814
1815#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1816
1817template <class _Tp>
1818struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1819    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1820
1821#else
1822
1823template<typename _Tp> char &__is_polymorphic_impl(
1824    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1825                       int>::type);
1826template<typename _Tp> __two &__is_polymorphic_impl(...);
1827
1828template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1829    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1830
1831#endif // __has_feature(is_polymorphic)
1832
1833#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1834template <class _Tp>
1835_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_polymorphic_v
1836    = is_polymorphic<_Tp>::value;
1837#endif
1838
1839// has_virtual_destructor
1840
1841#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1842
1843template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1844    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1845
1846#else
1847
1848template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1849    : public false_type {};
1850
1851#endif
1852
1853#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1854template <class _Tp>
1855_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_virtual_destructor_v
1856    = has_virtual_destructor<_Tp>::value;
1857#endif
1858
1859// has_unique_object_representations
1860
1861#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_UNIQUE_OBJECT_REPRESENTATIONS)
1862
1863template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1864    : public integral_constant<bool,
1865       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1866
1867#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1868template <class _Tp>
1869_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool has_unique_object_representations_v
1870    = has_unique_object_representations<_Tp>::value;
1871#endif
1872
1873#endif
1874
1875// alignment_of
1876
1877template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1878    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1879
1880#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1881template <class _Tp>
1882_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR size_t alignment_of_v
1883    = alignment_of<_Tp>::value;
1884#endif
1885
1886// aligned_storage
1887
1888template <class _Hp, class _Tp>
1889struct __type_list
1890{
1891    typedef _Hp _Head;
1892    typedef _Tp _Tail;
1893};
1894
1895struct __nat
1896{
1897#ifndef _LIBCPP_CXX03_LANG
1898    __nat() = delete;
1899    __nat(const __nat&) = delete;
1900    __nat& operator=(const __nat&) = delete;
1901    ~__nat() = delete;
1902#endif
1903};
1904
1905template <class _Tp>
1906struct __align_type
1907{
1908    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1909    typedef _Tp type;
1910};
1911
1912struct __struct_double {long double __lx;};
1913struct __struct_double4 {double __lx[4];};
1914
1915typedef
1916    __type_list<__align_type<unsigned char>,
1917    __type_list<__align_type<unsigned short>,
1918    __type_list<__align_type<unsigned int>,
1919    __type_list<__align_type<unsigned long>,
1920    __type_list<__align_type<unsigned long long>,
1921    __type_list<__align_type<double>,
1922    __type_list<__align_type<long double>,
1923    __type_list<__align_type<__struct_double>,
1924    __type_list<__align_type<__struct_double4>,
1925    __type_list<__align_type<int*>,
1926    __nat
1927    > > > > > > > > > > __all_types;
1928
1929template <size_t _Align>
1930struct _ALIGNAS(_Align) __fallback_overaligned {};
1931
1932template <class _TL, size_t _Align> struct __find_pod;
1933
1934template <class _Hp, size_t _Align>
1935struct __find_pod<__type_list<_Hp, __nat>, _Align>
1936{
1937    typedef typename conditional<
1938                             _Align == _Hp::value,
1939                             typename _Hp::type,
1940                             __fallback_overaligned<_Align>
1941                         >::type type;
1942};
1943
1944template <class _Hp, class _Tp, size_t _Align>
1945struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1946{
1947    typedef typename conditional<
1948                             _Align == _Hp::value,
1949                             typename _Hp::type,
1950                             typename __find_pod<_Tp, _Align>::type
1951                         >::type type;
1952};
1953
1954template <class _TL, size_t _Len> struct __find_max_align;
1955
1956template <class _Hp, size_t _Len>
1957struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
1958
1959template <size_t _Len, size_t _A1, size_t _A2>
1960struct __select_align
1961{
1962private:
1963    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
1964    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
1965public:
1966    static const size_t value = _Len < __max ? __min : __max;
1967};
1968
1969template <class _Hp, class _Tp, size_t _Len>
1970struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
1971    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
1972
1973template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1974struct _LIBCPP_TEMPLATE_VIS aligned_storage
1975{
1976    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
1977    union type
1978    {
1979        _Aligner __align;
1980        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
1981    };
1982};
1983
1984#if _LIBCPP_STD_VER > 11
1985template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1986    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
1987#endif
1988
1989#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
1990template <size_t _Len>\
1991struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
1992{\
1993    struct _ALIGNAS(n) type\
1994    {\
1995        unsigned char __lx[(_Len + n - 1)/n * n];\
1996    };\
1997}
1998
1999_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2000_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2001_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2002_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2003_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2004_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2005_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2006_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2007_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2008_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2009_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2010_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2011_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2012_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2013// PE/COFF does not support alignment beyond 8192 (=0x2000)
2014#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2015_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2016#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2017
2018#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2019
2020
2021// aligned_union
2022
2023template <size_t _I0, size_t ..._In>
2024struct __static_max;
2025
2026template <size_t _I0>
2027struct __static_max<_I0>
2028{
2029    static const size_t value = _I0;
2030};
2031
2032template <size_t _I0, size_t _I1, size_t ..._In>
2033struct __static_max<_I0, _I1, _In...>
2034{
2035    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2036                                             __static_max<_I1, _In...>::value;
2037};
2038
2039template <size_t _Len, class _Type0, class ..._Types>
2040struct aligned_union
2041{
2042    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2043                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2044    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2045                                             sizeof(_Types)...>::value;
2046    typedef typename aligned_storage<__len, alignment_value>::type type;
2047};
2048
2049#if _LIBCPP_STD_VER > 11
2050template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2051#endif
2052
2053template <class _Tp>
2054struct __numeric_type
2055{
2056   static void __test(...);
2057   static float __test(float);
2058   static double __test(char);
2059   static double __test(int);
2060   static double __test(unsigned);
2061   static double __test(long);
2062   static double __test(unsigned long);
2063   static double __test(long long);
2064   static double __test(unsigned long long);
2065   static double __test(double);
2066   static long double __test(long double);
2067
2068   typedef decltype(__test(declval<_Tp>())) type;
2069   static const bool value = _IsNotSame<type, void>::value;
2070};
2071
2072template <>
2073struct __numeric_type<void>
2074{
2075   static const bool value = true;
2076};
2077
2078// __promote
2079
2080template <class _A1, class _A2 = void, class _A3 = void,
2081          bool = __numeric_type<_A1>::value &&
2082                 __numeric_type<_A2>::value &&
2083                 __numeric_type<_A3>::value>
2084class __promote_imp
2085{
2086public:
2087    static const bool value = false;
2088};
2089
2090template <class _A1, class _A2, class _A3>
2091class __promote_imp<_A1, _A2, _A3, true>
2092{
2093private:
2094    typedef typename __promote_imp<_A1>::type __type1;
2095    typedef typename __promote_imp<_A2>::type __type2;
2096    typedef typename __promote_imp<_A3>::type __type3;
2097public:
2098    typedef decltype(__type1() + __type2() + __type3()) type;
2099    static const bool value = true;
2100};
2101
2102template <class _A1, class _A2>
2103class __promote_imp<_A1, _A2, void, true>
2104{
2105private:
2106    typedef typename __promote_imp<_A1>::type __type1;
2107    typedef typename __promote_imp<_A2>::type __type2;
2108public:
2109    typedef decltype(__type1() + __type2()) type;
2110    static const bool value = true;
2111};
2112
2113template <class _A1>
2114class __promote_imp<_A1, void, void, true>
2115{
2116public:
2117    typedef typename __numeric_type<_A1>::type type;
2118    static const bool value = true;
2119};
2120
2121template <class _A1, class _A2 = void, class _A3 = void>
2122class __promote : public __promote_imp<_A1, _A2, _A3> {};
2123
2124// make_signed / make_unsigned
2125
2126typedef
2127    __type_list<signed char,
2128    __type_list<signed short,
2129    __type_list<signed int,
2130    __type_list<signed long,
2131    __type_list<signed long long,
2132#ifndef _LIBCPP_HAS_NO_INT128
2133    __type_list<__int128_t,
2134#endif
2135    __nat
2136#ifndef _LIBCPP_HAS_NO_INT128
2137    >
2138#endif
2139    > > > > > __signed_types;
2140
2141typedef
2142    __type_list<unsigned char,
2143    __type_list<unsigned short,
2144    __type_list<unsigned int,
2145    __type_list<unsigned long,
2146    __type_list<unsigned long long,
2147#ifndef _LIBCPP_HAS_NO_INT128
2148    __type_list<__uint128_t,
2149#endif
2150    __nat
2151#ifndef _LIBCPP_HAS_NO_INT128
2152    >
2153#endif
2154    > > > > > __unsigned_types;
2155
2156template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2157
2158template <class _Hp, class _Tp, size_t _Size>
2159struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2160{
2161    typedef _LIBCPP_NODEBUG_TYPE _Hp type;
2162};
2163
2164template <class _Hp, class _Tp, size_t _Size>
2165struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2166{
2167    typedef _LIBCPP_NODEBUG_TYPE typename __find_first<_Tp, _Size>::type type;
2168};
2169
2170template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2171                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2172struct __apply_cv
2173{
2174    typedef _LIBCPP_NODEBUG_TYPE _Up type;
2175};
2176
2177template <class _Tp, class _Up>
2178struct __apply_cv<_Tp, _Up, true, false>
2179{
2180    typedef _LIBCPP_NODEBUG_TYPE const _Up type;
2181};
2182
2183template <class _Tp, class _Up>
2184struct __apply_cv<_Tp, _Up, false, true>
2185{
2186    typedef volatile _Up type;
2187};
2188
2189template <class _Tp, class _Up>
2190struct __apply_cv<_Tp, _Up, true, true>
2191{
2192    typedef const volatile _Up type;
2193};
2194
2195template <class _Tp, class _Up>
2196struct __apply_cv<_Tp&, _Up, false, false>
2197{
2198    typedef _Up& type;
2199};
2200
2201template <class _Tp, class _Up>
2202struct __apply_cv<_Tp&, _Up, true, false>
2203{
2204    typedef const _Up& type;
2205};
2206
2207template <class _Tp, class _Up>
2208struct __apply_cv<_Tp&, _Up, false, true>
2209{
2210    typedef volatile _Up& type;
2211};
2212
2213template <class _Tp, class _Up>
2214struct __apply_cv<_Tp&, _Up, true, true>
2215{
2216    typedef const volatile _Up& type;
2217};
2218
2219template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2220struct __make_signed {};
2221
2222template <class _Tp>
2223struct __make_signed<_Tp, true>
2224{
2225    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2226};
2227
2228template <> struct __make_signed<bool,               true> {};
2229template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2230template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2231template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2232template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2233template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2234template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2235template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2236template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2237#ifndef _LIBCPP_HAS_NO_INT128
2238template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2239template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2240#endif
2241
2242template <class _Tp>
2243struct _LIBCPP_TEMPLATE_VIS make_signed
2244{
2245    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2246};
2247
2248#if _LIBCPP_STD_VER > 11
2249template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2250#endif
2251
2252template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2253struct __make_unsigned {};
2254
2255template <class _Tp>
2256struct __make_unsigned<_Tp, true>
2257{
2258    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2259};
2260
2261template <> struct __make_unsigned<bool,               true> {};
2262template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2263template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2264template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2265template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2266template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2267template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2268template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2269template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2270#ifndef _LIBCPP_HAS_NO_INT128
2271template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2272template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2273#endif
2274
2275template <class _Tp>
2276struct _LIBCPP_TEMPLATE_VIS make_unsigned
2277{
2278    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2279};
2280
2281#if _LIBCPP_STD_VER > 11
2282template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2283#endif
2284
2285#if _LIBCPP_STD_VER > 14
2286template <class...> using void_t = void;
2287#endif
2288
2289#if _LIBCPP_STD_VER > 17
2290// Let COND_RES(X, Y) be:
2291template <class _Tp, class _Up>
2292using __cond_type = decltype(false ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>());
2293
2294template <class _Tp, class _Up, class = void>
2295struct __common_type3 {};
2296
2297// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
2298template <class _Tp, class _Up>
2299struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
2300{
2301    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
2302};
2303
2304template <class _Tp, class _Up, class = void>
2305struct __common_type2_imp : __common_type3<_Tp, _Up> {};
2306#else
2307template <class _Tp, class _Up, class = void>
2308struct __common_type2_imp {};
2309#endif
2310
2311// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
2312template <class _Tp, class _Up>
2313struct __common_type2_imp<_Tp, _Up,
2314                          typename __void_t<decltype(
2315                                            true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2316                                            )>::type>
2317{
2318  typedef _LIBCPP_NODEBUG_TYPE typename decay<decltype(
2319                         true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2320                         )>::type type;
2321};
2322
2323template <class, class = void>
2324struct __common_type_impl {};
2325
2326// Clang provides variadic templates in C++03 as an extension.
2327#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2328# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2329template <class... Tp>
2330struct __common_types;
2331template <class... _Tp>
2332struct _LIBCPP_TEMPLATE_VIS common_type;
2333#else
2334# define _LIBCPP_OPTIONAL_PACK(...)
2335struct __no_arg;
2336template <class _Tp, class _Up, class = __no_arg>
2337struct __common_types;
2338template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2339          class _Unused = __no_arg>
2340struct common_type {
2341  static_assert(sizeof(_Unused) == 0,
2342                "common_type accepts at most 3 arguments in C++03");
2343};
2344#endif // _LIBCPP_CXX03_LANG
2345
2346template <class _Tp, class _Up>
2347struct __common_type_impl<
2348    __common_types<_Tp, _Up>,
2349    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2350{
2351  typedef typename common_type<_Tp, _Up>::type type;
2352};
2353
2354template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2355struct __common_type_impl<
2356    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2357    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2358    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2359                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2360};
2361
2362// bullet 1 - sizeof...(Tp) == 0
2363
2364template <>
2365struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2366
2367// bullet 2 - sizeof...(Tp) == 1
2368
2369template <class _Tp>
2370struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2371    : public common_type<_Tp, _Tp> {};
2372
2373// bullet 3 - sizeof...(Tp) == 2
2374
2375// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
2376template <class _Tp, class _Up>
2377struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2378    : conditional<
2379        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2380        __common_type2_imp<_Tp, _Up>,
2381        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2382    >::type
2383{};
2384
2385// bullet 4 - sizeof...(Tp) > 2
2386
2387template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2388struct _LIBCPP_TEMPLATE_VIS
2389    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2390    : __common_type_impl<
2391          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2392
2393#undef _LIBCPP_OPTIONAL_PACK
2394
2395#if _LIBCPP_STD_VER > 11
2396template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2397#endif
2398
2399// is_assignable
2400
2401template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
2402
2403#if __has_keyword(__is_assignable)
2404
2405template<class _Tp, class _Up>
2406struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2407
2408#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2409template <class _Tp, class _Arg>
2410_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v = __is_assignable(_Tp, _Arg);
2411#endif
2412
2413#else // __has_keyword(__is_assignable)
2414
2415template <class _Tp, class _Arg>
2416typename __select_2nd<decltype((_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>())), true_type>::type
2417__is_assignable_test(int);
2418
2419template <class, class>
2420false_type __is_assignable_test(...);
2421
2422
2423template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2424struct __is_assignable_imp
2425    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2426
2427template <class _Tp, class _Arg>
2428struct __is_assignable_imp<_Tp, _Arg, true>
2429    : public false_type
2430{
2431};
2432
2433template <class _Tp, class _Arg>
2434struct is_assignable
2435    : public __is_assignable_imp<_Tp, _Arg> {};
2436
2437#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2438template <class _Tp, class _Arg>
2439_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_assignable_v
2440    = is_assignable<_Tp, _Arg>::value;
2441#endif
2442
2443#endif  // __has_keyword(__is_assignable)
2444
2445// is_copy_assignable
2446
2447template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2448    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2449                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2450
2451#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2452template <class _Tp>
2453_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_assignable_v
2454    = is_copy_assignable<_Tp>::value;
2455#endif
2456
2457// is_move_assignable
2458
2459template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2460    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2461                           typename add_rvalue_reference<_Tp>::type> {};
2462
2463#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2464template <class _Tp>
2465_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_assignable_v
2466    = is_move_assignable<_Tp>::value;
2467#endif
2468
2469// is_destructible
2470
2471#if __has_keyword(__is_destructible)
2472
2473template<class _Tp>
2474struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2475
2476#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2477template <class _Tp>
2478_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v = __is_destructible(_Tp);
2479#endif
2480
2481#else // __has_keyword(__is_destructible)
2482
2483//  if it's a reference, return true
2484//  if it's a function, return false
2485//  if it's   void,     return false
2486//  if it's an array of unknown bound, return false
2487//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
2488//    where _Up is remove_all_extents<_Tp>::type
2489
2490template <class>
2491struct __is_destructible_apply { typedef int type; };
2492
2493template <typename _Tp>
2494struct __is_destructor_wellformed {
2495    template <typename _Tp1>
2496    static char  __test (
2497        typename __is_destructible_apply<decltype(_VSTD::declval<_Tp1&>().~_Tp1())>::type
2498    );
2499
2500    template <typename _Tp1>
2501    static __two __test (...);
2502
2503    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2504};
2505
2506template <class _Tp, bool>
2507struct __destructible_imp;
2508
2509template <class _Tp>
2510struct __destructible_imp<_Tp, false>
2511   : public _VSTD::integral_constant<bool,
2512        __is_destructor_wellformed<typename _VSTD::remove_all_extents<_Tp>::type>::value> {};
2513
2514template <class _Tp>
2515struct __destructible_imp<_Tp, true>
2516    : public _VSTD::true_type {};
2517
2518template <class _Tp, bool>
2519struct __destructible_false;
2520
2521template <class _Tp>
2522struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, _VSTD::is_reference<_Tp>::value> {};
2523
2524template <class _Tp>
2525struct __destructible_false<_Tp, true> : public _VSTD::false_type {};
2526
2527template <class _Tp>
2528struct is_destructible
2529    : public __destructible_false<_Tp, _VSTD::is_function<_Tp>::value> {};
2530
2531template <class _Tp>
2532struct is_destructible<_Tp[]>
2533    : public _VSTD::false_type {};
2534
2535template <>
2536struct is_destructible<void>
2537    : public _VSTD::false_type {};
2538
2539#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2540template <class _Tp>
2541_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_destructible_v
2542    = is_destructible<_Tp>::value;
2543#endif
2544
2545#endif // __has_keyword(__is_destructible)
2546
2547// move
2548
2549template <class _Tp>
2550inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2551typename remove_reference<_Tp>::type&&
2552move(_Tp&& __t) _NOEXCEPT
2553{
2554    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tp>::type _Up;
2555    return static_cast<_Up&&>(__t);
2556}
2557
2558template <class _Tp>
2559inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2560_Tp&&
2561forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT
2562{
2563    return static_cast<_Tp&&>(__t);
2564}
2565
2566template <class _Tp>
2567inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2568_Tp&&
2569forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT
2570{
2571    static_assert(!is_lvalue_reference<_Tp>::value,
2572                  "can not forward an rvalue as an lvalue");
2573    return static_cast<_Tp&&>(__t);
2574}
2575
2576template <class _Tp>
2577inline _LIBCPP_INLINE_VISIBILITY
2578typename decay<_Tp>::type
2579__decay_copy(_Tp&& __t)
2580{
2581    return _VSTD::forward<_Tp>(__t);
2582}
2583
2584template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2585struct __member_pointer_traits_imp
2586{
2587};
2588
2589template <class _Rp, class _Class, class ..._Param>
2590struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2591{
2592    typedef _Class _ClassType;
2593    typedef _Rp _ReturnType;
2594    typedef _Rp (_FnType) (_Param...);
2595};
2596
2597template <class _Rp, class _Class, class ..._Param>
2598struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2599{
2600    typedef _Class _ClassType;
2601    typedef _Rp _ReturnType;
2602    typedef _Rp (_FnType) (_Param..., ...);
2603};
2604
2605template <class _Rp, class _Class, class ..._Param>
2606struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2607{
2608    typedef _Class const _ClassType;
2609    typedef _Rp _ReturnType;
2610    typedef _Rp (_FnType) (_Param...);
2611};
2612
2613template <class _Rp, class _Class, class ..._Param>
2614struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2615{
2616    typedef _Class const _ClassType;
2617    typedef _Rp _ReturnType;
2618    typedef _Rp (_FnType) (_Param..., ...);
2619};
2620
2621template <class _Rp, class _Class, class ..._Param>
2622struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2623{
2624    typedef _Class volatile _ClassType;
2625    typedef _Rp _ReturnType;
2626    typedef _Rp (_FnType) (_Param...);
2627};
2628
2629template <class _Rp, class _Class, class ..._Param>
2630struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2631{
2632    typedef _Class volatile _ClassType;
2633    typedef _Rp _ReturnType;
2634    typedef _Rp (_FnType) (_Param..., ...);
2635};
2636
2637template <class _Rp, class _Class, class ..._Param>
2638struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2639{
2640    typedef _Class const volatile _ClassType;
2641    typedef _Rp _ReturnType;
2642    typedef _Rp (_FnType) (_Param...);
2643};
2644
2645template <class _Rp, class _Class, class ..._Param>
2646struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2647{
2648    typedef _Class const volatile _ClassType;
2649    typedef _Rp _ReturnType;
2650    typedef _Rp (_FnType) (_Param..., ...);
2651};
2652
2653#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2654
2655template <class _Rp, class _Class, class ..._Param>
2656struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2657{
2658    typedef _Class& _ClassType;
2659    typedef _Rp _ReturnType;
2660    typedef _Rp (_FnType) (_Param...);
2661};
2662
2663template <class _Rp, class _Class, class ..._Param>
2664struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2665{
2666    typedef _Class& _ClassType;
2667    typedef _Rp _ReturnType;
2668    typedef _Rp (_FnType) (_Param..., ...);
2669};
2670
2671template <class _Rp, class _Class, class ..._Param>
2672struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2673{
2674    typedef _Class const& _ClassType;
2675    typedef _Rp _ReturnType;
2676    typedef _Rp (_FnType) (_Param...);
2677};
2678
2679template <class _Rp, class _Class, class ..._Param>
2680struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2681{
2682    typedef _Class const& _ClassType;
2683    typedef _Rp _ReturnType;
2684    typedef _Rp (_FnType) (_Param..., ...);
2685};
2686
2687template <class _Rp, class _Class, class ..._Param>
2688struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2689{
2690    typedef _Class volatile& _ClassType;
2691    typedef _Rp _ReturnType;
2692    typedef _Rp (_FnType) (_Param...);
2693};
2694
2695template <class _Rp, class _Class, class ..._Param>
2696struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2697{
2698    typedef _Class volatile& _ClassType;
2699    typedef _Rp _ReturnType;
2700    typedef _Rp (_FnType) (_Param..., ...);
2701};
2702
2703template <class _Rp, class _Class, class ..._Param>
2704struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2705{
2706    typedef _Class const volatile& _ClassType;
2707    typedef _Rp _ReturnType;
2708    typedef _Rp (_FnType) (_Param...);
2709};
2710
2711template <class _Rp, class _Class, class ..._Param>
2712struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2713{
2714    typedef _Class const volatile& _ClassType;
2715    typedef _Rp _ReturnType;
2716    typedef _Rp (_FnType) (_Param..., ...);
2717};
2718
2719template <class _Rp, class _Class, class ..._Param>
2720struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2721{
2722    typedef _Class&& _ClassType;
2723    typedef _Rp _ReturnType;
2724    typedef _Rp (_FnType) (_Param...);
2725};
2726
2727template <class _Rp, class _Class, class ..._Param>
2728struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2729{
2730    typedef _Class&& _ClassType;
2731    typedef _Rp _ReturnType;
2732    typedef _Rp (_FnType) (_Param..., ...);
2733};
2734
2735template <class _Rp, class _Class, class ..._Param>
2736struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2737{
2738    typedef _Class const&& _ClassType;
2739    typedef _Rp _ReturnType;
2740    typedef _Rp (_FnType) (_Param...);
2741};
2742
2743template <class _Rp, class _Class, class ..._Param>
2744struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2745{
2746    typedef _Class const&& _ClassType;
2747    typedef _Rp _ReturnType;
2748    typedef _Rp (_FnType) (_Param..., ...);
2749};
2750
2751template <class _Rp, class _Class, class ..._Param>
2752struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2753{
2754    typedef _Class volatile&& _ClassType;
2755    typedef _Rp _ReturnType;
2756    typedef _Rp (_FnType) (_Param...);
2757};
2758
2759template <class _Rp, class _Class, class ..._Param>
2760struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2761{
2762    typedef _Class volatile&& _ClassType;
2763    typedef _Rp _ReturnType;
2764    typedef _Rp (_FnType) (_Param..., ...);
2765};
2766
2767template <class _Rp, class _Class, class ..._Param>
2768struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2769{
2770    typedef _Class const volatile&& _ClassType;
2771    typedef _Rp _ReturnType;
2772    typedef _Rp (_FnType) (_Param...);
2773};
2774
2775template <class _Rp, class _Class, class ..._Param>
2776struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2777{
2778    typedef _Class const volatile&& _ClassType;
2779    typedef _Rp _ReturnType;
2780    typedef _Rp (_FnType) (_Param..., ...);
2781};
2782
2783#endif  // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2784
2785
2786template <class _Rp, class _Class>
2787struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2788{
2789    typedef _Class _ClassType;
2790    typedef _Rp _ReturnType;
2791};
2792
2793template <class _MP>
2794struct __member_pointer_traits
2795    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2796                    is_member_function_pointer<_MP>::value,
2797                    is_member_object_pointer<_MP>::value>
2798{
2799//     typedef ... _ClassType;
2800//     typedef ... _ReturnType;
2801//     typedef ... _FnType;
2802};
2803
2804
2805template <class _DecayedFp>
2806struct __member_pointer_class_type {};
2807
2808template <class _Ret, class _ClassType>
2809struct __member_pointer_class_type<_Ret _ClassType::*> {
2810  typedef _ClassType type;
2811};
2812
2813// template <class T, class... Args> struct is_constructible;
2814
2815#if defined(_LIBCPP_COMPILER_GCC) && _GNUC_VER_NEW >= 10000
2816# define _LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE
2817#endif
2818
2819#if !defined(_LIBCPP_CXX03_LANG) && !__has_feature(is_constructible) && !defined(_LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE)
2820
2821template <class _Tp, class... _Args>
2822struct __libcpp_is_constructible;
2823
2824template <class _To, class _From>
2825struct __is_invalid_base_to_derived_cast {
2826  static_assert(is_reference<_To>::value, "Wrong specialization");
2827  using _RawFrom = __uncvref_t<_From>;
2828  using _RawTo = __uncvref_t<_To>;
2829  static const bool value = _And<
2830        _IsNotSame<_RawFrom, _RawTo>,
2831        is_base_of<_RawFrom, _RawTo>,
2832        _Not<__libcpp_is_constructible<_RawTo, _From>>
2833  >::value;
2834};
2835
2836template <class _To, class _From>
2837struct __is_invalid_lvalue_to_rvalue_cast : false_type {
2838  static_assert(is_reference<_To>::value, "Wrong specialization");
2839};
2840
2841template <class _ToRef, class _FromRef>
2842struct __is_invalid_lvalue_to_rvalue_cast<_ToRef&&, _FromRef&> {
2843  using _RawFrom = __uncvref_t<_FromRef>;
2844  using _RawTo = __uncvref_t<_ToRef>;
2845  static const bool value = _And<
2846      _Not<is_function<_RawTo>>,
2847      _Or<
2848        _IsSame<_RawFrom, _RawTo>,
2849        is_base_of<_RawTo, _RawFrom>>
2850    >::value;
2851};
2852
2853struct __is_constructible_helper
2854{
2855    template <class _To>
2856    static void __eat(_To);
2857
2858    // This overload is needed to work around a Clang bug that disallows
2859    // static_cast<T&&>(e) for non-reference-compatible types.
2860    // Example: static_cast<int&&>(declval<double>());
2861    // NOTE: The static_cast implementation below is required to support
2862    //  classes with explicit conversion operators.
2863    template <class _To, class _From,
2864              class = decltype(__eat<_To>(_VSTD::declval<_From>()))>
2865    static true_type __test_cast(int);
2866
2867    template <class _To, class _From,
2868              class = decltype(static_cast<_To>(_VSTD::declval<_From>()))>
2869    static integral_constant<bool,
2870        !__is_invalid_base_to_derived_cast<_To, _From>::value &&
2871        !__is_invalid_lvalue_to_rvalue_cast<_To, _From>::value
2872    > __test_cast(long);
2873
2874    template <class, class>
2875    static false_type __test_cast(...);
2876
2877    template <class _Tp, class ..._Args,
2878        class = decltype(_Tp(_VSTD::declval<_Args>()...))>
2879    static true_type __test_nary(int);
2880    template <class _Tp, class...>
2881    static false_type __test_nary(...);
2882
2883    template <class _Tp, class _A0, class = decltype(::new _Tp(_VSTD::declval<_A0>()))>
2884    static is_destructible<_Tp> __test_unary(int);
2885    template <class, class>
2886    static false_type __test_unary(...);
2887};
2888
2889template <class _Tp, bool = is_void<_Tp>::value>
2890struct __is_default_constructible
2891    : decltype(__is_constructible_helper::__test_nary<_Tp>(0))
2892{};
2893
2894template <class _Tp>
2895struct __is_default_constructible<_Tp, true> : false_type {};
2896
2897template <class _Tp>
2898struct __is_default_constructible<_Tp[], false> : false_type {};
2899
2900template <class _Tp, size_t _Nx>
2901struct __is_default_constructible<_Tp[_Nx], false>
2902    : __is_default_constructible<typename remove_all_extents<_Tp>::type>  {};
2903
2904template <class _Tp, class... _Args>
2905struct __libcpp_is_constructible
2906{
2907  static_assert(sizeof...(_Args) > 1, "Wrong specialization");
2908  typedef decltype(__is_constructible_helper::__test_nary<_Tp, _Args...>(0))
2909      type;
2910};
2911
2912template <class _Tp>
2913struct __libcpp_is_constructible<_Tp> : __is_default_constructible<_Tp> {};
2914
2915template <class _Tp, class _A0>
2916struct __libcpp_is_constructible<_Tp, _A0>
2917    : public decltype(__is_constructible_helper::__test_unary<_Tp, _A0>(0))
2918{};
2919
2920template <class _Tp, class _A0>
2921struct __libcpp_is_constructible<_Tp&, _A0>
2922    : public decltype(__is_constructible_helper::
2923    __test_cast<_Tp&, _A0>(0))
2924{};
2925
2926template <class _Tp, class _A0>
2927struct __libcpp_is_constructible<_Tp&&, _A0>
2928    : public decltype(__is_constructible_helper::
2929    __test_cast<_Tp&&, _A0>(0))
2930{};
2931
2932#endif
2933
2934#if __has_feature(is_constructible) || defined(_LIBCPP_GCC_SUPPORTS_IS_CONSTRUCTIBLE)
2935template <class _Tp, class ..._Args>
2936struct _LIBCPP_TEMPLATE_VIS is_constructible
2937    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
2938    {};
2939#else
2940template <class _Tp, class... _Args>
2941struct _LIBCPP_TEMPLATE_VIS is_constructible
2942    : public __libcpp_is_constructible<_Tp, _Args...>::type {};
2943#endif
2944
2945#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2946template <class _Tp, class ..._Args>
2947_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_constructible_v
2948    = is_constructible<_Tp, _Args...>::value;
2949#endif
2950
2951// is_default_constructible
2952
2953template <class _Tp>
2954struct _LIBCPP_TEMPLATE_VIS is_default_constructible
2955    : public is_constructible<_Tp>
2956    {};
2957
2958#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2959template <class _Tp>
2960_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_default_constructible_v
2961    = is_default_constructible<_Tp>::value;
2962#endif
2963
2964#ifndef _LIBCPP_CXX03_LANG
2965// First of all, we can't implement this check in C++03 mode because the {}
2966// default initialization syntax isn't valid.
2967// Second, we implement the trait in a funny manner with two defaulted template
2968// arguments to workaround Clang's PR43454.
2969template <class _Tp>
2970void __test_implicit_default_constructible(_Tp);
2971
2972template <class _Tp, class = void, bool = is_default_constructible<_Tp>::value>
2973struct __is_implicitly_default_constructible
2974    : false_type
2975{ };
2976
2977template <class _Tp>
2978struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true>
2979    : true_type
2980{ };
2981
2982template <class _Tp>
2983struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false>
2984    : false_type
2985{ };
2986#endif // !C++03
2987
2988// is_copy_constructible
2989
2990template <class _Tp>
2991struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
2992    : public is_constructible<_Tp,
2993                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2994
2995#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2996template <class _Tp>
2997_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_copy_constructible_v
2998    = is_copy_constructible<_Tp>::value;
2999#endif
3000
3001// is_move_constructible
3002
3003template <class _Tp>
3004struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3005    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3006    {};
3007
3008#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3009template <class _Tp>
3010_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_move_constructible_v
3011    = is_move_constructible<_Tp>::value;
3012#endif
3013
3014// is_trivially_constructible
3015
3016#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3017
3018template <class _Tp, class... _Args>
3019struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3020    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3021{
3022};
3023
3024#else  // !__has_feature(is_trivially_constructible)
3025
3026template <class _Tp, class... _Args>
3027struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3028    : false_type
3029{
3030};
3031
3032template <class _Tp>
3033struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp>
3034#if __has_feature(has_trivial_constructor) || defined(_LIBCPP_COMPILER_GCC)
3035    : integral_constant<bool, __has_trivial_constructor(_Tp)>
3036#else
3037    : integral_constant<bool, is_scalar<_Tp>::value>
3038#endif
3039{
3040};
3041
3042template <class _Tp>
3043struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&&>
3044    : integral_constant<bool, is_scalar<_Tp>::value>
3045{
3046};
3047
3048template <class _Tp>
3049struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, const _Tp&>
3050    : integral_constant<bool, is_scalar<_Tp>::value>
3051{
3052};
3053
3054template <class _Tp>
3055struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible<_Tp, _Tp&>
3056    : integral_constant<bool, is_scalar<_Tp>::value>
3057{
3058};
3059
3060#endif  // !__has_feature(is_trivially_constructible)
3061
3062
3063#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3064template <class _Tp, class... _Args>
3065_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_constructible_v
3066    = is_trivially_constructible<_Tp, _Args...>::value;
3067#endif
3068
3069// is_trivially_default_constructible
3070
3071template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3072    : public is_trivially_constructible<_Tp>
3073    {};
3074
3075#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3076template <class _Tp>
3077_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_default_constructible_v
3078    = is_trivially_default_constructible<_Tp>::value;
3079#endif
3080
3081// is_trivially_copy_constructible
3082
3083template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3084    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3085    {};
3086
3087#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3088template <class _Tp>
3089_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_constructible_v
3090    = is_trivially_copy_constructible<_Tp>::value;
3091#endif
3092
3093// is_trivially_move_constructible
3094
3095template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3096    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3097    {};
3098
3099#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3100template <class _Tp>
3101_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_constructible_v
3102    = is_trivially_move_constructible<_Tp>::value;
3103#endif
3104
3105// is_trivially_assignable
3106
3107#if __has_feature(is_trivially_assignable) || _GNUC_VER >= 501
3108
3109template <class _Tp, class _Arg>
3110struct is_trivially_assignable
3111    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3112{
3113};
3114
3115#else  // !__has_feature(is_trivially_assignable)
3116
3117template <class _Tp, class _Arg>
3118struct is_trivially_assignable
3119    : public false_type {};
3120
3121template <class _Tp>
3122struct is_trivially_assignable<_Tp&, _Tp>
3123    : integral_constant<bool, is_scalar<_Tp>::value> {};
3124
3125template <class _Tp>
3126struct is_trivially_assignable<_Tp&, _Tp&>
3127    : integral_constant<bool, is_scalar<_Tp>::value> {};
3128
3129template <class _Tp>
3130struct is_trivially_assignable<_Tp&, const _Tp&>
3131    : integral_constant<bool, is_scalar<_Tp>::value> {};
3132
3133template <class _Tp>
3134struct is_trivially_assignable<_Tp&, _Tp&&>
3135    : integral_constant<bool, is_scalar<_Tp>::value> {};
3136
3137#endif  // !__has_feature(is_trivially_assignable)
3138
3139#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3140template <class _Tp, class _Arg>
3141_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_assignable_v
3142    = is_trivially_assignable<_Tp, _Arg>::value;
3143#endif
3144
3145// is_trivially_copy_assignable
3146
3147template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3148    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3149                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3150
3151#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3152template <class _Tp>
3153_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copy_assignable_v
3154    = is_trivially_copy_assignable<_Tp>::value;
3155#endif
3156
3157// is_trivially_move_assignable
3158
3159template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3160    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3161                                     typename add_rvalue_reference<_Tp>::type>
3162    {};
3163
3164#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3165template <class _Tp>
3166_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_move_assignable_v
3167    = is_trivially_move_assignable<_Tp>::value;
3168#endif
3169
3170// is_trivially_destructible
3171
3172#if __has_keyword(__is_trivially_destructible)
3173
3174template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3175    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3176
3177#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3178
3179template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3180    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3181
3182#else
3183
3184template <class _Tp> struct __libcpp_trivial_destructor
3185    : public integral_constant<bool, is_scalar<_Tp>::value ||
3186                                     is_reference<_Tp>::value> {};
3187
3188template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3189    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3190
3191template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3192    : public false_type {};
3193
3194#endif
3195
3196#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3197template <class _Tp>
3198_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_destructible_v
3199    = is_trivially_destructible<_Tp>::value;
3200#endif
3201
3202// is_nothrow_constructible
3203
3204#if __has_keyword(__is_nothrow_constructible)
3205
3206template <class _Tp, class... _Args>
3207struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3208    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3209
3210#else
3211
3212template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3213
3214template <class _Tp, class... _Args>
3215struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3216    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3217{
3218};
3219
3220template <class _Tp>
3221void __implicit_conversion_to(_Tp) noexcept { }
3222
3223template <class _Tp, class _Arg>
3224struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3225    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3226{
3227};
3228
3229template <class _Tp, bool _IsReference, class... _Args>
3230struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3231    : public false_type
3232{
3233};
3234
3235template <class _Tp, class... _Args>
3236struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3237    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3238{
3239};
3240
3241template <class _Tp, size_t _Ns>
3242struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3243    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3244{
3245};
3246
3247#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3248
3249
3250#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3251template <class _Tp, class ..._Args>
3252_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_constructible_v
3253    = is_nothrow_constructible<_Tp, _Args...>::value;
3254#endif
3255
3256// is_nothrow_default_constructible
3257
3258template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3259    : public is_nothrow_constructible<_Tp>
3260    {};
3261
3262#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3263template <class _Tp>
3264_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_default_constructible_v
3265    = is_nothrow_default_constructible<_Tp>::value;
3266#endif
3267
3268// is_nothrow_copy_constructible
3269
3270template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3271    : public is_nothrow_constructible<_Tp,
3272                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3273
3274#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3275template <class _Tp>
3276_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_constructible_v
3277    = is_nothrow_copy_constructible<_Tp>::value;
3278#endif
3279
3280// is_nothrow_move_constructible
3281
3282template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3283    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3284    {};
3285
3286#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3287template <class _Tp>
3288_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_constructible_v
3289    = is_nothrow_move_constructible<_Tp>::value;
3290#endif
3291
3292// is_nothrow_assignable
3293
3294#if __has_keyword(__is_nothrow_assignable)
3295
3296template <class _Tp, class _Arg>
3297struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3298    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3299
3300#else
3301
3302template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3303
3304template <class _Tp, class _Arg>
3305struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3306    : public false_type
3307{
3308};
3309
3310template <class _Tp, class _Arg>
3311struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3312    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>()) >
3313{
3314};
3315
3316template <class _Tp, class _Arg>
3317struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3318    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3319{
3320};
3321
3322#endif  // _LIBCPP_HAS_NO_NOEXCEPT
3323
3324#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3325template <class _Tp, class _Arg>
3326_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_assignable_v
3327    = is_nothrow_assignable<_Tp, _Arg>::value;
3328#endif
3329
3330// is_nothrow_copy_assignable
3331
3332template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3333    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3334                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3335
3336#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3337template <class _Tp>
3338_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_copy_assignable_v
3339    = is_nothrow_copy_assignable<_Tp>::value;
3340#endif
3341
3342// is_nothrow_move_assignable
3343
3344template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3345    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3346                                     typename add_rvalue_reference<_Tp>::type>
3347    {};
3348
3349#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3350template <class _Tp>
3351_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_move_assignable_v
3352    = is_nothrow_move_assignable<_Tp>::value;
3353#endif
3354
3355// is_nothrow_destructible
3356
3357#if !defined(_LIBCPP_CXX03_LANG)
3358
3359template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3360
3361template <class _Tp>
3362struct __libcpp_is_nothrow_destructible<false, _Tp>
3363    : public false_type
3364{
3365};
3366
3367template <class _Tp>
3368struct __libcpp_is_nothrow_destructible<true, _Tp>
3369    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>().~_Tp()) >
3370{
3371};
3372
3373template <class _Tp>
3374struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3375    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3376{
3377};
3378
3379template <class _Tp, size_t _Ns>
3380struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3381    : public is_nothrow_destructible<_Tp>
3382{
3383};
3384
3385template <class _Tp>
3386struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3387    : public true_type
3388{
3389};
3390
3391template <class _Tp>
3392struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3393    : public true_type
3394{
3395};
3396
3397#else
3398
3399template <class _Tp> struct __libcpp_nothrow_destructor
3400    : public integral_constant<bool, is_scalar<_Tp>::value ||
3401                                     is_reference<_Tp>::value> {};
3402
3403template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3404    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3405
3406template <class _Tp>
3407struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3408    : public false_type {};
3409
3410#endif
3411
3412#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3413template <class _Tp>
3414_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_nothrow_destructible_v
3415    = is_nothrow_destructible<_Tp>::value;
3416#endif
3417
3418// is_pod
3419
3420#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3421
3422template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3423    : public integral_constant<bool, __is_pod(_Tp)> {};
3424
3425#else
3426
3427template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3428    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3429                                     is_trivially_copy_constructible<_Tp>::value      &&
3430                                     is_trivially_copy_assignable<_Tp>::value    &&
3431                                     is_trivially_destructible<_Tp>::value> {};
3432
3433#endif
3434
3435#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3436template <class _Tp>
3437_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_pod_v
3438    = is_pod<_Tp>::value;
3439#endif
3440
3441// is_literal_type;
3442
3443template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_literal_type
3444    : public integral_constant<bool, __is_literal_type(_Tp)>
3445    {};
3446
3447#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3448template <class _Tp>
3449_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_literal_type_v
3450    = is_literal_type<_Tp>::value;
3451#endif
3452
3453// is_standard_layout;
3454
3455template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3456#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3457    : public integral_constant<bool, __is_standard_layout(_Tp)>
3458#else
3459    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3460#endif
3461    {};
3462
3463#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3464template <class _Tp>
3465_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_standard_layout_v
3466    = is_standard_layout<_Tp>::value;
3467#endif
3468
3469// is_trivially_copyable;
3470
3471template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3472#if __has_feature(is_trivially_copyable)
3473    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3474#elif _GNUC_VER >= 501
3475    : public integral_constant<bool, !is_volatile<_Tp>::value && __is_trivially_copyable(_Tp)>
3476#else
3477    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3478#endif
3479    {};
3480
3481#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3482template <class _Tp>
3483_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivially_copyable_v
3484    = is_trivially_copyable<_Tp>::value;
3485#endif
3486
3487// is_trivial;
3488
3489template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3490#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3491    : public integral_constant<bool, __is_trivial(_Tp)>
3492#else
3493    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3494                                 is_trivially_default_constructible<_Tp>::value>
3495#endif
3496    {};
3497
3498#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3499template <class _Tp>
3500_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_trivial_v
3501    = is_trivial<_Tp>::value;
3502#endif
3503
3504template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3505template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3506template <class _Tp> struct __is_reference_wrapper
3507    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3508
3509#ifndef _LIBCPP_CXX03_LANG
3510
3511template <class _Fp, class _A0,
3512         class _DecayFp = typename decay<_Fp>::type,
3513         class _DecayA0 = typename decay<_A0>::type,
3514         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3515using __enable_if_bullet1 = typename enable_if
3516    <
3517        is_member_function_pointer<_DecayFp>::value
3518        && is_base_of<_ClassT, _DecayA0>::value
3519    >::type;
3520
3521template <class _Fp, class _A0,
3522         class _DecayFp = typename decay<_Fp>::type,
3523         class _DecayA0 = typename decay<_A0>::type>
3524using __enable_if_bullet2 = typename enable_if
3525    <
3526        is_member_function_pointer<_DecayFp>::value
3527        && __is_reference_wrapper<_DecayA0>::value
3528    >::type;
3529
3530template <class _Fp, class _A0,
3531         class _DecayFp = typename decay<_Fp>::type,
3532         class _DecayA0 = typename decay<_A0>::type,
3533         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3534using __enable_if_bullet3 = typename enable_if
3535    <
3536        is_member_function_pointer<_DecayFp>::value
3537        && !is_base_of<_ClassT, _DecayA0>::value
3538        && !__is_reference_wrapper<_DecayA0>::value
3539    >::type;
3540
3541template <class _Fp, class _A0,
3542         class _DecayFp = typename decay<_Fp>::type,
3543         class _DecayA0 = typename decay<_A0>::type,
3544         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3545using __enable_if_bullet4 = typename enable_if
3546    <
3547        is_member_object_pointer<_DecayFp>::value
3548        && is_base_of<_ClassT, _DecayA0>::value
3549    >::type;
3550
3551template <class _Fp, class _A0,
3552         class _DecayFp = typename decay<_Fp>::type,
3553         class _DecayA0 = typename decay<_A0>::type>
3554using __enable_if_bullet5 = typename enable_if
3555    <
3556        is_member_object_pointer<_DecayFp>::value
3557        && __is_reference_wrapper<_DecayA0>::value
3558    >::type;
3559
3560template <class _Fp, class _A0,
3561         class _DecayFp = typename decay<_Fp>::type,
3562         class _DecayA0 = typename decay<_A0>::type,
3563         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3564using __enable_if_bullet6 = typename enable_if
3565    <
3566        is_member_object_pointer<_DecayFp>::value
3567        && !is_base_of<_ClassT, _DecayA0>::value
3568        && !__is_reference_wrapper<_DecayA0>::value
3569    >::type;
3570
3571// __invoke forward declarations
3572
3573// fall back - none of the bullets
3574
3575#define _LIBCPP_INVOKE_RETURN(...) \
3576    noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) \
3577    { return __VA_ARGS__; }
3578
3579template <class ..._Args>
3580auto __invoke(__any, _Args&& ...__args) -> __nat;
3581
3582template <class ..._Args>
3583auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3584
3585// bullets 1, 2 and 3
3586
3587template <class _Fp, class _A0, class ..._Args,
3588          class = __enable_if_bullet1<_Fp, _A0>>
3589inline _LIBCPP_INLINE_VISIBILITY
3590_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3591__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3592_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3593
3594template <class _Fp, class _A0, class ..._Args,
3595          class = __enable_if_bullet1<_Fp, _A0>>
3596inline _LIBCPP_INLINE_VISIBILITY
3597_LIBCPP_CONSTEXPR auto
3598__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3599_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
3600
3601template <class _Fp, class _A0, class ..._Args,
3602          class = __enable_if_bullet2<_Fp, _A0>>
3603inline _LIBCPP_INLINE_VISIBILITY
3604_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3605__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3606_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3607
3608template <class _Fp, class _A0, class ..._Args,
3609          class = __enable_if_bullet2<_Fp, _A0>>
3610inline _LIBCPP_INLINE_VISIBILITY
3611_LIBCPP_CONSTEXPR auto
3612__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3613_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
3614
3615template <class _Fp, class _A0, class ..._Args,
3616          class = __enable_if_bullet3<_Fp, _A0>>
3617inline _LIBCPP_INLINE_VISIBILITY
3618_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3619__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3620_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3621
3622template <class _Fp, class _A0, class ..._Args,
3623          class = __enable_if_bullet3<_Fp, _A0>>
3624inline _LIBCPP_INLINE_VISIBILITY
3625_LIBCPP_CONSTEXPR auto
3626__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3627_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
3628
3629// bullets 4, 5 and 6
3630
3631template <class _Fp, class _A0,
3632          class = __enable_if_bullet4<_Fp, _A0>>
3633inline _LIBCPP_INLINE_VISIBILITY
3634_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3635__invoke(_Fp&& __f, _A0&& __a0)
3636_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3637
3638template <class _Fp, class _A0,
3639          class = __enable_if_bullet4<_Fp, _A0>>
3640inline _LIBCPP_INLINE_VISIBILITY
3641_LIBCPP_CONSTEXPR auto
3642__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3643_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
3644
3645template <class _Fp, class _A0,
3646          class = __enable_if_bullet5<_Fp, _A0>>
3647inline _LIBCPP_INLINE_VISIBILITY
3648_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3649__invoke(_Fp&& __f, _A0&& __a0)
3650_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3651
3652template <class _Fp, class _A0,
3653          class = __enable_if_bullet5<_Fp, _A0>>
3654inline _LIBCPP_INLINE_VISIBILITY
3655_LIBCPP_CONSTEXPR auto
3656__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3657_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
3658
3659template <class _Fp, class _A0,
3660          class = __enable_if_bullet6<_Fp, _A0>>
3661inline _LIBCPP_INLINE_VISIBILITY
3662_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3663__invoke(_Fp&& __f, _A0&& __a0)
3664_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3665
3666template <class _Fp, class _A0,
3667          class = __enable_if_bullet6<_Fp, _A0>>
3668inline _LIBCPP_INLINE_VISIBILITY
3669_LIBCPP_CONSTEXPR auto
3670__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3671_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
3672
3673// bullet 7
3674
3675template <class _Fp, class ..._Args>
3676inline _LIBCPP_INLINE_VISIBILITY
3677_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3678__invoke(_Fp&& __f, _Args&& ...__args)
3679_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3680
3681template <class _Fp, class ..._Args>
3682inline _LIBCPP_INLINE_VISIBILITY
3683_LIBCPP_CONSTEXPR auto
3684__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3685_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
3686
3687#undef _LIBCPP_INVOKE_RETURN
3688
3689// __invokable
3690template <class _Ret, class _Fp, class ..._Args>
3691struct __invokable_r
3692{
3693  template <class _XFp, class ..._XArgs>
3694  static auto __try_call(int) -> decltype(
3695    _VSTD::__invoke(_VSTD::declval<_XFp>(), _VSTD::declval<_XArgs>()...));
3696  template <class _XFp, class ..._XArgs>
3697  static __nat __try_call(...);
3698
3699  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3700  // or incomplete array types as required by the standard.
3701  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3702
3703  using type =
3704  typename conditional<
3705      _IsNotSame<_Result, __nat>::value,
3706      typename conditional<
3707          is_void<_Ret>::value,
3708          true_type,
3709          is_convertible<_Result, _Ret>
3710      >::type,
3711      false_type
3712  >::type;
3713  static const bool value = type::value;
3714};
3715template <class _Fp, class ..._Args>
3716using __invokable = __invokable_r<void, _Fp, _Args...>;
3717
3718template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3719struct __nothrow_invokable_r_imp {
3720  static const bool value = false;
3721};
3722
3723template <class _Ret, class _Fp, class ..._Args>
3724struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3725{
3726    typedef __nothrow_invokable_r_imp _ThisT;
3727
3728    template <class _Tp>
3729    static void __test_noexcept(_Tp) noexcept;
3730
3731    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3732        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...)));
3733};
3734
3735template <class _Ret, class _Fp, class ..._Args>
3736struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3737{
3738    static const bool value = noexcept(
3739        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...));
3740};
3741
3742template <class _Ret, class _Fp, class ..._Args>
3743using __nothrow_invokable_r =
3744    __nothrow_invokable_r_imp<
3745            __invokable_r<_Ret, _Fp, _Args...>::value,
3746            is_void<_Ret>::value,
3747            _Ret, _Fp, _Args...
3748    >;
3749
3750template <class _Fp, class ..._Args>
3751using __nothrow_invokable =
3752    __nothrow_invokable_r_imp<
3753            __invokable<_Fp, _Args...>::value,
3754            true, void, _Fp, _Args...
3755    >;
3756
3757template <class _Fp, class ..._Args>
3758struct __invoke_of
3759    : public enable_if<
3760        __invokable<_Fp, _Args...>::value,
3761        typename __invokable_r<void, _Fp, _Args...>::_Result>
3762{
3763};
3764
3765#endif // _LIBCPP_CXX03_LANG
3766
3767// result_of
3768
3769template <class _Callable> class result_of;
3770
3771#ifndef _LIBCPP_CXX03_LANG
3772
3773template <class _Fp, class ..._Args>
3774class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3775    : public __invoke_of<_Fp, _Args...>
3776{
3777};
3778
3779#else // C++03
3780
3781template <class _Fn, bool, bool>
3782class __result_of
3783{
3784};
3785
3786template <class _Fn, class ..._Args>
3787class __result_of<_Fn(_Args...), true, false>
3788{
3789public:
3790    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
3791};
3792
3793template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
3794struct __result_of_mp;
3795
3796// member function pointer
3797
3798template <class _MP, class _Tp>
3799struct __result_of_mp<_MP, _Tp, true>
3800    : public __identity<typename __member_pointer_traits<_MP>::_ReturnType>
3801{
3802};
3803
3804// member data pointer
3805
3806template <class _MP, class _Tp, bool>
3807struct __result_of_mdp;
3808
3809template <class _Rp, class _Class, class _Tp>
3810struct __result_of_mdp<_Rp _Class::*, _Tp, false>
3811{
3812    typedef typename __apply_cv<decltype(*_VSTD::declval<_Tp>()), _Rp>::type& type;
3813};
3814
3815template <class _Rp, class _Class, class _Tp>
3816struct __result_of_mdp<_Rp _Class::*, _Tp, true>
3817{
3818    typedef typename __apply_cv<_Tp, _Rp>::type& type;
3819};
3820
3821template <class _Rp, class _Class, class _Tp>
3822struct __result_of_mp<_Rp _Class::*, _Tp, false>
3823    : public __result_of_mdp<_Rp _Class::*, _Tp,
3824            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
3825{
3826};
3827
3828template <class _Fn, class _Tp>
3829class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
3830    : public __result_of_mp<typename remove_reference<_Fn>::type,
3831                            _Tp,
3832                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3833{
3834};
3835
3836template <class _Fn, class _Tp, class ..._Args>
3837class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
3838    : public __result_of_mp<typename remove_reference<_Fn>::type,
3839                            _Tp,
3840                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3841{
3842};
3843
3844template <class _Fn, class ..._Args>
3845class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
3846    : public __result_of<_Fn(_Args...),
3847                         is_class<typename remove_reference<_Fn>::type>::value ||
3848                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3849                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3850                        >
3851{
3852};
3853
3854#endif  // C++03
3855
3856#if _LIBCPP_STD_VER > 11
3857template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
3858#endif
3859
3860#if _LIBCPP_STD_VER > 14
3861
3862// invoke_result
3863
3864template <class _Fn, class... _Args>
3865struct _LIBCPP_TEMPLATE_VIS invoke_result
3866    : __invoke_of<_Fn, _Args...>
3867{
3868};
3869
3870template <class _Fn, class... _Args>
3871using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3872
3873// is_invocable
3874
3875template <class _Fn, class ..._Args>
3876struct _LIBCPP_TEMPLATE_VIS is_invocable
3877    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
3878
3879template <class _Ret, class _Fn, class ..._Args>
3880struct _LIBCPP_TEMPLATE_VIS is_invocable_r
3881    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
3882
3883template <class _Fn, class ..._Args>
3884_LIBCPP_INLINE_VAR constexpr bool is_invocable_v
3885    = is_invocable<_Fn, _Args...>::value;
3886
3887template <class _Ret, class _Fn, class ..._Args>
3888_LIBCPP_INLINE_VAR constexpr bool is_invocable_r_v
3889    = is_invocable_r<_Ret, _Fn, _Args...>::value;
3890
3891// is_nothrow_invocable
3892
3893template <class _Fn, class ..._Args>
3894struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
3895    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
3896
3897template <class _Ret, class _Fn, class ..._Args>
3898struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
3899    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
3900
3901template <class _Fn, class ..._Args>
3902_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_v
3903    = is_nothrow_invocable<_Fn, _Args...>::value;
3904
3905template <class _Ret, class _Fn, class ..._Args>
3906_LIBCPP_INLINE_VAR constexpr bool is_nothrow_invocable_r_v
3907    = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3908
3909#endif // _LIBCPP_STD_VER > 14
3910
3911template <class _Tp> struct __is_swappable;
3912template <class _Tp> struct __is_nothrow_swappable;
3913
3914// swap, swap_ranges
3915
3916template <class _ForwardIterator1, class _ForwardIterator2>
3917inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3918_ForwardIterator2
3919swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2);
3920
3921template <class _Tp>
3922inline _LIBCPP_INLINE_VISIBILITY
3923#ifndef _LIBCPP_CXX03_LANG
3924typename enable_if
3925<
3926    is_move_constructible<_Tp>::value &&
3927    is_move_assignable<_Tp>::value
3928>::type
3929#else
3930void
3931#endif
3932_LIBCPP_CONSTEXPR_AFTER_CXX17
3933swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
3934                                    is_nothrow_move_assignable<_Tp>::value)
3935{
3936    _Tp __t(_VSTD::move(__x));
3937    __x = _VSTD::move(__y);
3938    __y = _VSTD::move(__t);
3939}
3940
3941template<class _Tp, size_t _Np>
3942inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3943typename enable_if<
3944    __is_swappable<_Tp>::value
3945>::type
3946swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
3947{
3948    _VSTD::swap_ranges(__a, __a + _Np, __b);
3949}
3950
3951template <class _ForwardIterator1, class _ForwardIterator2>
3952inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3953_ForwardIterator2
3954swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
3955{
3956    for(; __first1 != __last1; ++__first1, (void) ++__first2)
3957        swap(*__first1, *__first2);
3958    return __first2;
3959}
3960
3961// iter_swap
3962
3963template <class _ForwardIterator1, class _ForwardIterator2>
3964inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3965void
3966iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
3967    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
3968               _NOEXCEPT_(_NOEXCEPT_(swap(*_VSTD::declval<_ForwardIterator1>(),
3969                                          *_VSTD::declval<_ForwardIterator2>())))
3970{
3971    swap(*__a, *__b);
3972}
3973
3974// __swappable
3975
3976namespace __detail
3977{
3978// ALL generic swap overloads MUST already have a declaration available at this point.
3979
3980template <class _Tp, class _Up = _Tp,
3981          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
3982struct __swappable_with
3983{
3984    template <class _LHS, class _RHS>
3985    static decltype(swap(_VSTD::declval<_LHS>(), _VSTD::declval<_RHS>()))
3986    __test_swap(int);
3987    template <class, class>
3988    static __nat __test_swap(long);
3989
3990    // Extra parens are needed for the C++03 definition of decltype.
3991    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
3992    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
3993
3994    static const bool value = _IsNotSame<__swap1, __nat>::value
3995                           && _IsNotSame<__swap2, __nat>::value;
3996};
3997
3998template <class _Tp, class _Up>
3999struct __swappable_with<_Tp, _Up,  false> : false_type {};
4000
4001template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
4002struct __nothrow_swappable_with {
4003  static const bool value =
4004#ifndef _LIBCPP_HAS_NO_NOEXCEPT
4005      noexcept(swap(_VSTD::declval<_Tp>(), _VSTD::declval<_Up>()))
4006  &&  noexcept(swap(_VSTD::declval<_Up>(), _VSTD::declval<_Tp>()));
4007#else
4008      false;
4009#endif
4010};
4011
4012template <class _Tp, class _Up>
4013struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
4014
4015}  // __detail
4016
4017template <class _Tp>
4018struct __is_swappable
4019    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
4020{
4021};
4022
4023template <class _Tp>
4024struct __is_nothrow_swappable
4025    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
4026{
4027};
4028
4029#if _LIBCPP_STD_VER > 14
4030
4031template <class _Tp, class _Up>
4032struct _LIBCPP_TEMPLATE_VIS is_swappable_with
4033    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
4034{
4035};
4036
4037template <class _Tp>
4038struct _LIBCPP_TEMPLATE_VIS is_swappable
4039    : public conditional<
4040        __is_referenceable<_Tp>::value,
4041        is_swappable_with<
4042            typename add_lvalue_reference<_Tp>::type,
4043            typename add_lvalue_reference<_Tp>::type>,
4044        false_type
4045    >::type
4046{
4047};
4048
4049template <class _Tp, class _Up>
4050struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
4051    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
4052{
4053};
4054
4055template <class _Tp>
4056struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
4057    : public conditional<
4058        __is_referenceable<_Tp>::value,
4059        is_nothrow_swappable_with<
4060            typename add_lvalue_reference<_Tp>::type,
4061            typename add_lvalue_reference<_Tp>::type>,
4062        false_type
4063    >::type
4064{
4065};
4066
4067template <class _Tp, class _Up>
4068_LIBCPP_INLINE_VAR constexpr bool is_swappable_with_v
4069    = is_swappable_with<_Tp, _Up>::value;
4070
4071template <class _Tp>
4072_LIBCPP_INLINE_VAR constexpr bool is_swappable_v
4073    = is_swappable<_Tp>::value;
4074
4075template <class _Tp, class _Up>
4076_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_with_v
4077    = is_nothrow_swappable_with<_Tp, _Up>::value;
4078
4079template <class _Tp>
4080_LIBCPP_INLINE_VAR constexpr bool is_nothrow_swappable_v
4081    = is_nothrow_swappable<_Tp>::value;
4082
4083#endif // _LIBCPP_STD_VER > 14
4084
4085template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4086
4087template <class _Tp>
4088struct __underlying_type_impl<_Tp, false> {};
4089
4090template <class _Tp>
4091struct __underlying_type_impl<_Tp, true>
4092{
4093    typedef __underlying_type(_Tp) type;
4094};
4095
4096template <class _Tp>
4097struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4098
4099#if _LIBCPP_STD_VER > 11
4100template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4101#endif
4102
4103template <class _Tp, bool = is_enum<_Tp>::value>
4104struct __sfinae_underlying_type
4105{
4106    typedef typename underlying_type<_Tp>::type type;
4107    typedef decltype(((type)1) + 0) __promoted_type;
4108};
4109
4110template <class _Tp>
4111struct __sfinae_underlying_type<_Tp, false> {};
4112
4113inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4114int __convert_to_integral(int __val) { return __val; }
4115
4116inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4117unsigned __convert_to_integral(unsigned __val) { return __val; }
4118
4119inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4120long __convert_to_integral(long __val) { return __val; }
4121
4122inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4123unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4124
4125inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4126long long __convert_to_integral(long long __val) { return __val; }
4127
4128inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4129unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4130
4131template<typename _Fp>
4132inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4133typename enable_if<is_floating_point<_Fp>::value, long long>::type
4134 __convert_to_integral(_Fp __val) { return __val; }
4135
4136#ifndef _LIBCPP_HAS_NO_INT128
4137inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4138__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4139
4140inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4141__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4142#endif
4143
4144template <class _Tp>
4145inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4146typename __sfinae_underlying_type<_Tp>::__promoted_type
4147__convert_to_integral(_Tp __val) { return __val; }
4148
4149#ifndef _LIBCPP_CXX03_LANG
4150
4151template <class _Tp>
4152struct __has_operator_addressof_member_imp
4153{
4154    template <class _Up>
4155        static auto __test(int)
4156            -> typename __select_2nd<decltype(_VSTD::declval<_Up>().operator&()), true_type>::type;
4157    template <class>
4158        static auto __test(long) -> false_type;
4159
4160    static const bool value = decltype(__test<_Tp>(0))::value;
4161};
4162
4163template <class _Tp>
4164struct __has_operator_addressof_free_imp
4165{
4166    template <class _Up>
4167        static auto __test(int)
4168            -> typename __select_2nd<decltype(operator&(_VSTD::declval<_Up>())), true_type>::type;
4169    template <class>
4170        static auto __test(long) -> false_type;
4171
4172    static const bool value = decltype(__test<_Tp>(0))::value;
4173};
4174
4175template <class _Tp>
4176struct __has_operator_addressof
4177    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
4178                                  || __has_operator_addressof_free_imp<_Tp>::value>
4179{};
4180
4181#endif  // _LIBCPP_CXX03_LANG
4182
4183// is_scoped_enum [meta.unary.prop]
4184
4185#if _LIBCPP_STD_VER > 20
4186template <class _Tp, bool = is_enum_v<_Tp> >
4187struct __is_scoped_enum_helper : false_type {};
4188
4189template <class _Tp>
4190struct __is_scoped_enum_helper<_Tp, true>
4191    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
4192
4193template <class _Tp>
4194struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
4195    : public __is_scoped_enum_helper<_Tp> {};
4196
4197template <class _Tp>
4198_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_scoped_enum_v =
4199    is_scoped_enum<_Tp>::value;
4200#endif
4201
4202#if _LIBCPP_STD_VER > 14
4203
4204template <class... _Args>
4205struct conjunction : _And<_Args...> {};
4206template<class... _Args>
4207_LIBCPP_INLINE_VAR constexpr bool conjunction_v
4208    = conjunction<_Args...>::value;
4209
4210template <class... _Args>
4211struct disjunction : _Or<_Args...> {};
4212template<class... _Args>
4213_LIBCPP_INLINE_VAR constexpr bool disjunction_v
4214    = disjunction<_Args...>::value;
4215
4216template <class _Tp>
4217struct negation : _Not<_Tp> {};
4218template<class _Tp>
4219_LIBCPP_INLINE_VAR constexpr bool negation_v
4220    = negation<_Tp>::value;
4221#endif  // _LIBCPP_STD_VER > 14
4222
4223// These traits are used in __tree and __hash_table
4224struct __extract_key_fail_tag {};
4225struct __extract_key_self_tag {};
4226struct __extract_key_first_tag {};
4227
4228template <class _ValTy, class _Key,
4229          class _RawValTy = typename __unconstref<_ValTy>::type>
4230struct __can_extract_key
4231    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4232                  __extract_key_fail_tag>::type {};
4233
4234template <class _Pair, class _Key, class _First, class _Second>
4235struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
4236    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4237                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4238
4239// __can_extract_map_key uses true_type/false_type instead of the tags.
4240// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4241// and _ValTy == _Key.
4242template <class _ValTy, class _Key, class _ContainerValueTy,
4243          class _RawValTy = typename __unconstref<_ValTy>::type>
4244struct __can_extract_map_key
4245    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4246
4247// This specialization returns __extract_key_fail_tag for non-map containers
4248// because _Key == _ContainerValueTy
4249template <class _ValTy, class _Key, class _RawValTy>
4250struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4251    : false_type {};
4252
4253#ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
4254#if _LIBCPP_STD_VER > 17
4255_LIBCPP_INLINE_VISIBILITY
4256inline constexpr bool is_constant_evaluated() noexcept {
4257  return __builtin_is_constant_evaluated();
4258}
4259#endif
4260
4261inline _LIBCPP_CONSTEXPR
4262bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4263#else
4264inline _LIBCPP_CONSTEXPR
4265bool __libcpp_is_constant_evaluated() _NOEXCEPT { return false; }
4266#endif
4267
4268template <class _CharT>
4269using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4270
4271_LIBCPP_END_NAMESPACE_STD
4272
4273#if _LIBCPP_STD_VER > 14
4274// std::byte
4275namespace std  // purposefully not versioned
4276{
4277
4278
4279}
4280#endif
4281
4282#endif  // _LIBCPP_TYPE_TRAITS
4283