1// -*- C++ -*-
2//===------------------------ type_traits ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_TYPE_TRAITS
12#define _LIBCPP_TYPE_TRAITS
13
14/*
15    type_traits synopsis
16
17namespace std
18{
19
20    // helper class:
21    template <class T, T v> struct integral_constant;
22    typedef integral_constant<bool, true>  true_type;   // C++11
23    typedef integral_constant<bool, false> false_type;  // C++11
24
25    template <bool B>                                   // C++14
26    using bool_constant = integral_constant<bool, B>;   // C++14
27    typedef bool_constant<true> true_type;              // C++14
28    typedef bool_constant<false> false_type;            // C++14
29
30    // helper traits
31    template <bool, class T = void> struct enable_if;
32    template <bool, class T, class F> struct conditional;
33
34    // Primary classification traits:
35    template <class T> struct is_void;
36    template <class T> struct is_null_pointer;  // C++14
37    template <class T> struct is_integral;
38    template <class T> struct is_floating_point;
39    template <class T> struct is_array;
40    template <class T> struct is_pointer;
41    template <class T> struct is_lvalue_reference;
42    template <class T> struct is_rvalue_reference;
43    template <class T> struct is_member_object_pointer;
44    template <class T> struct is_member_function_pointer;
45    template <class T> struct is_enum;
46    template <class T> struct is_union;
47    template <class T> struct is_class;
48    template <class T> struct is_function;
49
50    // Secondary classification traits:
51    template <class T> struct is_reference;
52    template <class T> struct is_arithmetic;
53    template <class T> struct is_fundamental;
54    template <class T> struct is_member_pointer;
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    // Integral properties:
79    template <class T> struct is_signed;
80    template <class T> struct is_unsigned;
81    template <class T> struct make_signed;
82    template <class T> struct make_unsigned;
83
84    // Array properties and transformations:
85    template <class T> struct rank;
86    template <class T, unsigned I = 0> struct extent;
87    template <class T> struct remove_extent;
88    template <class T> struct remove_all_extents;
89
90    // Member introspection:
91    template <class T> struct is_pod;
92    template <class T> struct is_trivial;
93    template <class T> struct is_trivially_copyable;
94    template <class T> struct is_standard_layout;
95    template <class T> struct is_literal_type;
96    template <class T> struct is_empty;
97    template <class T> struct is_polymorphic;
98    template <class T> struct is_abstract;
99    template <class T> struct is_final; // C++14
100
101    template <class T, class... Args> struct is_constructible;
102    template <class T>                struct is_default_constructible;
103    template <class T>                struct is_copy_constructible;
104    template <class T>                struct is_move_constructible;
105    template <class T, class U>       struct is_assignable;
106    template <class T>                struct is_copy_assignable;
107    template <class T>                struct is_move_assignable;
108    template <class T, class U>       struct is_swappable_with;       // C++17
109    template <class T>                struct is_swappable;            // C++17
110    template <class T>                struct is_destructible;
111
112    template <class T, class... Args> struct is_trivially_constructible;
113    template <class T>                struct is_trivially_default_constructible;
114    template <class T>                struct is_trivially_copy_constructible;
115    template <class T>                struct is_trivially_move_constructible;
116    template <class T, class U>       struct is_trivially_assignable;
117    template <class T>                struct is_trivially_copy_assignable;
118    template <class T>                struct is_trivially_move_assignable;
119    template <class T>                struct is_trivially_destructible;
120
121    template <class T, class... Args> struct is_nothrow_constructible;
122    template <class T>                struct is_nothrow_default_constructible;
123    template <class T>                struct is_nothrow_copy_constructible;
124    template <class T>                struct is_nothrow_move_constructible;
125    template <class T, class U>       struct is_nothrow_assignable;
126    template <class T>                struct is_nothrow_copy_assignable;
127    template <class T>                struct is_nothrow_move_assignable;
128    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
129    template <class T>                struct is_nothrow_swappable;      // C++17
130    template <class T>                struct is_nothrow_destructible;
131
132    template <class T> struct has_virtual_destructor;
133
134    // Relationships between types:
135    template <class T, class U> struct is_same;
136    template <class Base, class Derived> struct is_base_of;
137    template <class From, class To> struct is_convertible;
138
139    template <class, class R = void> struct is_callable; // not defined
140    template <class Fn, class... ArgTypes, class R>
141      struct is_callable<Fn(ArgTypes...), R>;
142
143    template <class, class R = void> struct is_nothrow_callable; // not defined
144    template <class Fn, class... ArgTypes, class R>
145      struct is_nothrow_callable<Fn(ArgTypes...), R>;
146
147    // Alignment properties and transformations:
148    template <class T> struct alignment_of;
149    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
150        struct aligned_storage;
151    template <size_t Len, class... Types> struct aligned_union;
152
153    template <class T> struct decay;
154    template <class... T> struct common_type;
155    template <class T> struct underlying_type;
156    template <class> class result_of; // undefined
157    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>;
158
159    // const-volatile modifications:
160    template <class T>
161      using remove_const_t    = typename remove_const<T>::type;  // C++14
162    template <class T>
163      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
164    template <class T>
165      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
166    template <class T>
167      using add_const_t       = typename add_const<T>::type;  // C++14
168    template <class T>
169      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
170    template <class T>
171      using add_cv_t          = typename add_cv<T>::type;  // C++14
172
173    // reference modifications:
174    template <class T>
175      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
176    template <class T>
177      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
178    template <class T>
179      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
180
181    // sign modifications:
182    template <class T>
183      using make_signed_t   = typename make_signed<T>::type;  // C++14
184    template <class T>
185      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
186
187    // array modifications:
188    template <class T>
189      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
190    template <class T>
191      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
192
193    // pointer modifications:
194    template <class T>
195      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
196    template <class T>
197      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
198
199    // other transformations:
200    template <size_t Len, std::size_t Align=default-alignment>
201      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
202    template <std::size_t Len, class... Types>
203      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
204    template <class T>
205      using decay_t           = typename decay<T>::type;  // C++14
206    template <bool b, class T=void>
207      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
208    template <bool b, class T, class F>
209      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
210    template <class... T>
211      using common_type_t     = typename common_type<T...>::type;  // C++14
212    template <class T>
213      using underlying_type_t = typename underlying_type<T>::type;  // C++14
214    template <class F, class... ArgTypes>
215      using result_of_t       = typename result_of<F(ArgTypes...)>::type;  // C++14
216
217    template <class...>
218      using void_t = void;   // C++17
219
220      // See C++14 20.10.4.1, primary type categories
221      template <class T> constexpr bool is_void_v
222        = is_void<T>::value;                                             // C++17
223      template <class T> constexpr bool is_null_pointer_v
224        = is_null_pointer<T>::value;                                     // C++17
225      template <class T> constexpr bool is_integral_v
226        = is_integral<T>::value;                                         // C++17
227      template <class T> constexpr bool is_floating_point_v
228        = is_floating_point<T>::value;                                   // C++17
229      template <class T> constexpr bool is_array_v
230        = is_array<T>::value;                                            // C++17
231      template <class T> constexpr bool is_pointer_v
232        = is_pointer<T>::value;                                          // C++17
233      template <class T> constexpr bool is_lvalue_reference_v
234        = is_lvalue_reference<T>::value;                                 // C++17
235      template <class T> constexpr bool is_rvalue_reference_v
236        = is_rvalue_reference<T>::value;                                 // C++17
237      template <class T> constexpr bool is_member_object_pointer_v
238        = is_member_object_pointer<T>::value;                            // C++17
239      template <class T> constexpr bool is_member_function_pointer_v
240        = is_member_function_pointer<T>::value;                          // C++17
241      template <class T> constexpr bool is_enum_v
242        = is_enum<T>::value;                                             // C++17
243      template <class T> constexpr bool is_union_v
244        = is_union<T>::value;                                            // C++17
245      template <class T> constexpr bool is_class_v
246        = is_class<T>::value;                                            // C++17
247      template <class T> constexpr bool is_function_v
248        = is_function<T>::value;                                         // C++17
249
250      // See C++14 20.10.4.2, composite type categories
251      template <class T> constexpr bool is_reference_v
252        = is_reference<T>::value;                                        // C++17
253      template <class T> constexpr bool is_arithmetic_v
254        = is_arithmetic<T>::value;                                       // C++17
255      template <class T> constexpr bool is_fundamental_v
256        = is_fundamental<T>::value;                                      // C++17
257      template <class T> constexpr bool is_object_v
258        = is_object<T>::value;                                           // C++17
259      template <class T> constexpr bool is_scalar_v
260        = is_scalar<T>::value;                                           // C++17
261      template <class T> constexpr bool is_compound_v
262        = is_compound<T>::value;                                         // C++17
263      template <class T> constexpr bool is_member_pointer_v
264        = is_member_pointer<T>::value;                                   // C++17
265
266      // See C++14 20.10.4.3, type properties
267      template <class T> constexpr bool is_const_v
268        = is_const<T>::value;                                            // C++17
269      template <class T> constexpr bool is_volatile_v
270        = is_volatile<T>::value;                                         // C++17
271      template <class T> constexpr bool is_trivial_v
272        = is_trivial<T>::value;                                          // C++17
273      template <class T> constexpr bool is_trivially_copyable_v
274        = is_trivially_copyable<T>::value;                               // C++17
275      template <class T> constexpr bool is_standard_layout_v
276        = is_standard_layout<T>::value;                                  // C++17
277      template <class T> constexpr bool is_pod_v
278        = is_pod<T>::value;                                              // C++17
279      template <class T> constexpr bool is_literal_type_v
280        = is_literal_type<T>::value;                                     // C++17
281      template <class T> constexpr bool is_empty_v
282        = is_empty<T>::value;                                            // C++17
283      template <class T> constexpr bool is_polymorphic_v
284        = is_polymorphic<T>::value;                                      // C++17
285      template <class T> constexpr bool is_abstract_v
286        = is_abstract<T>::value;                                         // C++17
287      template <class T> constexpr bool is_final_v
288        = is_final<T>::value;                                            // C++17
289      template <class T> constexpr bool is_signed_v
290        = is_signed<T>::value;                                           // C++17
291      template <class T> constexpr bool is_unsigned_v
292        = is_unsigned<T>::value;                                         // C++17
293      template <class T, class... Args> constexpr bool is_constructible_v
294        = is_constructible<T, Args...>::value;                           // C++17
295      template <class T> constexpr bool is_default_constructible_v
296        = is_default_constructible<T>::value;                            // C++17
297      template <class T> constexpr bool is_copy_constructible_v
298        = is_copy_constructible<T>::value;                               // C++17
299      template <class T> constexpr bool is_move_constructible_v
300        = is_move_constructible<T>::value;                               // C++17
301      template <class T, class U> constexpr bool is_assignable_v
302        = is_assignable<T, U>::value;                                    // C++17
303      template <class T> constexpr bool is_copy_assignable_v
304        = is_copy_assignable<T>::value;                                  // C++17
305      template <class T> constexpr bool is_move_assignable_v
306        = is_move_assignable<T>::value;                                  // C++17
307      template <class T, class U> constexpr bool is_swappable_with_v
308        = is_swappable_with<T, U>::value;                                // C++17
309      template <class T> constexpr bool is_swappable_v
310        = is_swappable<T>::value;                                        // C++17
311      template <class T> constexpr bool is_destructible_v
312        = is_destructible<T>::value;                                     // C++17
313      template <class T, class... Args> constexpr bool is_trivially_constructible_v
314        = is_trivially_constructible<T, Args...>::value;                 // C++17
315      template <class T> constexpr bool is_trivially_default_constructible_v
316        = is_trivially_default_constructible<T>::value;                  // C++17
317      template <class T> constexpr bool is_trivially_copy_constructible_v
318        = is_trivially_copy_constructible<T>::value;                     // C++17
319      template <class T> constexpr bool is_trivially_move_constructible_v
320        = is_trivially_move_constructible<T>::value;                     // C++17
321      template <class T, class U> constexpr bool is_trivially_assignable_v
322        = is_trivially_assignable<T, U>::value;                          // C++17
323      template <class T> constexpr bool is_trivially_copy_assignable_v
324        = is_trivially_copy_assignable<T>::value;                        // C++17
325      template <class T> constexpr bool is_trivially_move_assignable_v
326        = is_trivially_move_assignable<T>::value;                        // C++17
327      template <class T> constexpr bool is_trivially_destructible_v
328        = is_trivially_destructible<T>::value;                           // C++17
329      template <class T, class... Args> constexpr bool is_nothrow_constructible_v
330        = is_nothrow_constructible<T, Args...>::value;                   // C++17
331      template <class T> constexpr bool is_nothrow_default_constructible_v
332        = is_nothrow_default_constructible<T>::value;                    // C++17
333      template <class T> constexpr bool is_nothrow_copy_constructible_v
334        = is_nothrow_copy_constructible<T>::value;                       // C++17
335      template <class T> constexpr bool is_nothrow_move_constructible_v
336        = is_nothrow_move_constructible<T>::value;                       // C++17
337      template <class T, class U> constexpr bool is_nothrow_assignable_v
338        = is_nothrow_assignable<T, U>::value;                            // C++17
339      template <class T> constexpr bool is_nothrow_copy_assignable_v
340        = is_nothrow_copy_assignable<T>::value;                          // C++17
341      template <class T> constexpr bool is_nothrow_move_assignable_v
342        = is_nothrow_move_assignable<T>::value;                          // C++17
343      template <class T, class U> constexpr bool is_nothrow_swappable_with_v
344        = is_nothrow_swappable_with<T, U>::value;                       // C++17
345      template <class T> constexpr bool is_nothrow_swappable_v
346        = is_nothrow_swappable<T>::value;                               // C++17
347      template <class T> constexpr bool is_nothrow_destructible_v
348        = is_nothrow_destructible<T>::value;                             // C++17
349      template <class T> constexpr bool has_virtual_destructor_v
350        = has_virtual_destructor<T>::value;                              // C++17
351
352      // See C++14 20.10.5, type property queries
353      template <class T> constexpr size_t alignment_of_v
354        = alignment_of<T>::value;                                        // C++17
355      template <class T> constexpr size_t rank_v
356        = rank<T>::value;                                                // C++17
357      template <class T, unsigned I = 0> constexpr size_t extent_v
358        = extent<T, I>::value;                                           // C++17
359
360      // See C++14 20.10.6, type relations
361      template <class T, class U> constexpr bool is_same_v
362        = is_same<T, U>::value;                                          // C++17
363      template <class Base, class Derived> constexpr bool is_base_of_v
364        = is_base_of<Base, Derived>::value;                              // C++17
365      template <class From, class To> constexpr bool is_convertible_v
366        = is_convertible<From, To>::value;                               // C++17
367      template <class T, class R = void> constexpr bool is_callable_v
368        = is_callable<T, R>::value;                                      // C++17
369      template <class T, class R = void> constexpr bool is_nothrow_callable_v
370        = is_nothrow_callable<T, R>::value;                              // C++17
371
372      // [meta.logical], logical operator traits:
373      template<class... B> struct conjunction;                           // C++17
374      template<class... B>
375        constexpr bool conjunction_v = conjunction<B...>::value;         // C++17
376      template<class... B> struct disjunction;                           // C++17
377      template<class... B>
378        constexpr bool disjunction_v = disjunction<B...>::value;         // C++17
379      template<class B> struct negation;                                 // C++17
380      template<class B>
381        constexpr bool negation_v = negation<B>::value;                  // C++17
382
383}
384
385*/
386#include <__config>
387#include <cstddef>
388
389#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
390#pragma GCC system_header
391#endif
392
393_LIBCPP_BEGIN_NAMESPACE_STD
394
395template <class _T1, class _T2> struct _LIBCPP_TYPE_VIS_ONLY pair;
396template <class _Tp> class _LIBCPP_TYPE_VIS_ONLY reference_wrapper;
397template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY hash;
398
399template <class>
400struct __void_t { typedef void type; };
401
402template <class _Tp>
403struct __identity { typedef _Tp type; };
404
405template <class _Tp, bool>
406struct _LIBCPP_TYPE_VIS_ONLY __dependent_type : public _Tp {};
407
408template <bool _Bp, class _If, class _Then>
409    struct _LIBCPP_TYPE_VIS_ONLY conditional {typedef _If type;};
410template <class _If, class _Then>
411    struct _LIBCPP_TYPE_VIS_ONLY conditional<false, _If, _Then> {typedef _Then type;};
412
413#if _LIBCPP_STD_VER > 11
414template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
415#endif
416
417template <bool, class _Tp> struct _LIBCPP_TYPE_VIS_ONLY __lazy_enable_if {};
418template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY __lazy_enable_if<true, _Tp> {typedef typename _Tp::type type;};
419
420template <bool, class _Tp = void> struct _LIBCPP_TYPE_VIS_ONLY enable_if {};
421template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY enable_if<true, _Tp> {typedef _Tp type;};
422
423#if _LIBCPP_STD_VER > 11
424template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
425#endif
426
427// addressof
428#if __has_builtin(__builtin_addressof) || _GNUC_VER >= 700
429
430template <class _Tp>
431inline _LIBCPP_CONSTEXPR_AFTER_CXX14
432_LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
433_Tp*
434addressof(_Tp& __x) _NOEXCEPT
435{
436    return __builtin_addressof(__x);
437}
438
439#else
440
441template <class _Tp>
442inline _LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
443_Tp*
444addressof(_Tp& __x) _NOEXCEPT
445{
446    return (_Tp*)&reinterpret_cast<const volatile char&>(__x);
447}
448
449#endif // __has_builtin(__builtin_addressof)
450
451#if defined(_LIBCPP_HAS_OBJC_ARC) && !defined(_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF)
452// Objective-C++ Automatic Reference Counting uses qualified pointers
453// that require special addressof() signatures. When
454// _LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF is defined, the compiler
455// itself is providing these definitions. Otherwise, we provide them.
456template <class _Tp>
457inline _LIBCPP_INLINE_VISIBILITY
458__strong _Tp*
459addressof(__strong _Tp& __x) _NOEXCEPT
460{
461  return &__x;
462}
463
464#ifdef _LIBCPP_HAS_OBJC_ARC_WEAK
465template <class _Tp>
466inline _LIBCPP_INLINE_VISIBILITY
467__weak _Tp*
468addressof(__weak _Tp& __x) _NOEXCEPT
469{
470  return &__x;
471}
472#endif
473
474template <class _Tp>
475inline _LIBCPP_INLINE_VISIBILITY
476__autoreleasing _Tp*
477addressof(__autoreleasing _Tp& __x) _NOEXCEPT
478{
479  return &__x;
480}
481
482template <class _Tp>
483inline _LIBCPP_INLINE_VISIBILITY
484__unsafe_unretained _Tp*
485addressof(__unsafe_unretained _Tp& __x) _NOEXCEPT
486{
487  return &__x;
488}
489#endif
490
491struct __two {char __lx[2];};
492
493// helper class:
494
495template <class _Tp, _Tp __v>
496struct _LIBCPP_TYPE_VIS_ONLY integral_constant
497{
498    static _LIBCPP_CONSTEXPR const _Tp      value = __v;
499    typedef _Tp               value_type;
500    typedef integral_constant type;
501    _LIBCPP_INLINE_VISIBILITY
502        _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
503#if _LIBCPP_STD_VER > 11
504    _LIBCPP_INLINE_VISIBILITY
505         constexpr value_type operator ()() const _NOEXCEPT {return value;}
506#endif
507};
508
509template <class _Tp, _Tp __v>
510_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
511
512#if _LIBCPP_STD_VER > 14
513template <bool __b>
514using bool_constant = integral_constant<bool, __b>;
515#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
516#else
517#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
518#endif
519
520typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
521typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
522
523#if !defined(_LIBCPP_HAS_NO_VARIADICS)
524
525// __lazy_and
526
527template <bool _Last, class ..._Preds>
528struct __lazy_and_impl;
529
530template <class ..._Preds>
531struct __lazy_and_impl<false, _Preds...> : false_type {};
532
533template <>
534struct __lazy_and_impl<true> : true_type {};
535
536template <class _Pred>
537struct __lazy_and_impl<true, _Pred> : integral_constant<bool, _Pred::type::value> {};
538
539template <class _Hp, class ..._Tp>
540struct __lazy_and_impl<true, _Hp, _Tp...> : __lazy_and_impl<_Hp::type::value, _Tp...> {};
541
542template <class _P1, class ..._Pr>
543struct __lazy_and : __lazy_and_impl<_P1::type::value, _Pr...> {};
544
545// __lazy_or
546
547template <bool _List, class ..._Preds>
548struct __lazy_or_impl;
549
550template <class ..._Preds>
551struct __lazy_or_impl<true, _Preds...> : true_type {};
552
553template <>
554struct __lazy_or_impl<false> : false_type {};
555
556template <class _Hp, class ..._Tp>
557struct __lazy_or_impl<false, _Hp, _Tp...>
558        : __lazy_or_impl<_Hp::type::value, _Tp...> {};
559
560template <class _P1, class ..._Pr>
561struct __lazy_or : __lazy_or_impl<_P1::type::value, _Pr...> {};
562
563// __lazy_not
564
565template <class _Pred>
566struct __lazy_not : integral_constant<bool, !_Pred::type::value> {};
567
568// __and_
569template<class...> struct __and_;
570template<> struct __and_<> : true_type {};
571
572template<class _B0> struct __and_<_B0> : _B0 {};
573
574template<class _B0, class _B1>
575struct __and_<_B0, _B1> : conditional<_B0::value, _B1, _B0>::type {};
576
577template<class _B0, class _B1, class _B2, class... _Bn>
578struct __and_<_B0, _B1, _B2, _Bn...>
579        : conditional<_B0::value, __and_<_B1, _B2, _Bn...>, _B0>::type {};
580
581// __or_
582template<class...> struct __or_;
583template<> struct __or_<> : false_type {};
584
585template<class _B0> struct __or_<_B0> : _B0 {};
586
587template<class _B0, class _B1>
588struct __or_<_B0, _B1> : conditional<_B0::value, _B0, _B1>::type {};
589
590template<class _B0, class _B1, class _B2, class... _Bn>
591struct __or_<_B0, _B1, _B2, _Bn...>
592        : conditional<_B0::value, _B0, __or_<_B1, _B2, _Bn...> >::type {};
593
594// __not_
595template<class _Tp>
596struct __not_ : conditional<_Tp::value, false_type, true_type>::type {};
597
598#endif // !defined(_LIBCPP_HAS_NO_VARIADICS)
599
600// is_const
601
602template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_const            : public false_type {};
603template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_const<_Tp const> : public true_type {};
604
605#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
606template <class _Tp> _LIBCPP_CONSTEXPR bool is_const_v
607    = is_const<_Tp>::value;
608#endif
609
610// is_volatile
611
612template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_volatile               : public false_type {};
613template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_volatile<_Tp volatile> : public true_type {};
614
615#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
616template <class _Tp> _LIBCPP_CONSTEXPR bool is_volatile_v
617    = is_volatile<_Tp>::value;
618#endif
619
620// remove_const
621
622template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_const            {typedef _Tp type;};
623template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_const<const _Tp> {typedef _Tp type;};
624#if _LIBCPP_STD_VER > 11
625template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
626#endif
627
628// remove_volatile
629
630template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_volatile               {typedef _Tp type;};
631template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_volatile<volatile _Tp> {typedef _Tp type;};
632#if _LIBCPP_STD_VER > 11
633template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
634#endif
635
636// remove_cv
637
638template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_cv
639{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
640#if _LIBCPP_STD_VER > 11
641template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
642#endif
643
644// is_void
645
646template <class _Tp> struct __libcpp_is_void       : public false_type {};
647template <>          struct __libcpp_is_void<void> : public true_type {};
648
649template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_void
650    : public __libcpp_is_void<typename remove_cv<_Tp>::type> {};
651
652#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
653template <class _Tp> _LIBCPP_CONSTEXPR bool is_void_v
654    = is_void<_Tp>::value;
655#endif
656
657// __is_nullptr_t
658
659template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
660template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
661
662template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY __is_nullptr_t
663    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
664
665#if _LIBCPP_STD_VER > 11
666template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_null_pointer
667    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
668
669#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
670template <class _Tp> _LIBCPP_CONSTEXPR bool is_null_pointer_v
671    = is_null_pointer<_Tp>::value;
672#endif
673#endif
674
675// is_integral
676
677template <class _Tp> struct __libcpp_is_integral                     : public false_type {};
678template <>          struct __libcpp_is_integral<bool>               : public true_type {};
679template <>          struct __libcpp_is_integral<char>               : public true_type {};
680template <>          struct __libcpp_is_integral<signed char>        : public true_type {};
681template <>          struct __libcpp_is_integral<unsigned char>      : public true_type {};
682template <>          struct __libcpp_is_integral<wchar_t>            : public true_type {};
683#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
684template <>          struct __libcpp_is_integral<char16_t>           : public true_type {};
685template <>          struct __libcpp_is_integral<char32_t>           : public true_type {};
686#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
687template <>          struct __libcpp_is_integral<short>              : public true_type {};
688template <>          struct __libcpp_is_integral<unsigned short>     : public true_type {};
689template <>          struct __libcpp_is_integral<int>                : public true_type {};
690template <>          struct __libcpp_is_integral<unsigned int>       : public true_type {};
691template <>          struct __libcpp_is_integral<long>               : public true_type {};
692template <>          struct __libcpp_is_integral<unsigned long>      : public true_type {};
693template <>          struct __libcpp_is_integral<long long>          : public true_type {};
694template <>          struct __libcpp_is_integral<unsigned long long> : public true_type {};
695#ifndef _LIBCPP_HAS_NO_INT128
696template <>          struct __libcpp_is_integral<__int128_t>         : public true_type {};
697template <>          struct __libcpp_is_integral<__uint128_t>        : public true_type {};
698#endif
699
700template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_integral
701    : public __libcpp_is_integral<typename remove_cv<_Tp>::type> {};
702
703#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
704template <class _Tp> _LIBCPP_CONSTEXPR bool is_integral_v
705    = is_integral<_Tp>::value;
706#endif
707
708// is_floating_point
709
710template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
711template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
712template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
713template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
714
715template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_floating_point
716    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
717
718#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
719template <class _Tp> _LIBCPP_CONSTEXPR bool is_floating_point_v
720    = is_floating_point<_Tp>::value;
721#endif
722
723// is_array
724
725template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_array
726    : public false_type {};
727template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_array<_Tp[]>
728    : public true_type {};
729template <class _Tp, size_t _Np> struct _LIBCPP_TYPE_VIS_ONLY is_array<_Tp[_Np]>
730    : public true_type {};
731
732#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
733template <class _Tp> _LIBCPP_CONSTEXPR bool is_array_v
734    = is_array<_Tp>::value;
735#endif
736
737// is_pointer
738
739template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
740template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
741
742template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_pointer
743    : public __libcpp_is_pointer<typename remove_cv<_Tp>::type> {};
744
745#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
746template <class _Tp> _LIBCPP_CONSTEXPR bool is_pointer_v
747    = is_pointer<_Tp>::value;
748#endif
749
750// is_reference
751
752template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_lvalue_reference       : public false_type {};
753template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_lvalue_reference<_Tp&> : public true_type {};
754
755template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_rvalue_reference        : public false_type {};
756#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
757template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_rvalue_reference<_Tp&&> : public true_type {};
758#endif
759
760template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_reference        : public false_type {};
761template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_reference<_Tp&>  : public true_type {};
762#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
763template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_reference<_Tp&&> : public true_type {};
764#endif
765
766#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
767template <class _Tp> _LIBCPP_CONSTEXPR bool is_reference_v
768    = is_reference<_Tp>::value;
769
770template <class _Tp> _LIBCPP_CONSTEXPR bool is_lvalue_reference_v
771    = is_lvalue_reference<_Tp>::value;
772
773template <class _Tp> _LIBCPP_CONSTEXPR bool is_rvalue_reference_v
774    = is_rvalue_reference<_Tp>::value;
775#endif
776// is_union
777
778#if __has_feature(is_union) || (_GNUC_VER >= 403)
779
780template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_union
781    : public integral_constant<bool, __is_union(_Tp)> {};
782
783#else
784
785template <class _Tp> struct __libcpp_union : public false_type {};
786template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_union
787    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
788
789#endif
790
791#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
792template <class _Tp> _LIBCPP_CONSTEXPR bool is_union_v
793    = is_union<_Tp>::value;
794#endif
795
796// is_class
797
798#if __has_feature(is_class) || (_GNUC_VER >= 403)
799
800template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_class
801    : public integral_constant<bool, __is_class(_Tp)> {};
802
803#else
804
805namespace __is_class_imp
806{
807template <class _Tp> char  __test(int _Tp::*);
808template <class _Tp> __two __test(...);
809}
810
811template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_class
812    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
813
814#endif
815
816#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
817template <class _Tp> _LIBCPP_CONSTEXPR bool is_class_v
818    = is_class<_Tp>::value;
819#endif
820
821// is_same
822
823template <class _Tp, class _Up> struct _LIBCPP_TYPE_VIS_ONLY is_same           : public false_type {};
824template <class _Tp>            struct _LIBCPP_TYPE_VIS_ONLY is_same<_Tp, _Tp> : public true_type {};
825
826#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
827template <class _Tp, class _Up> _LIBCPP_CONSTEXPR bool is_same_v
828    = is_same<_Tp, _Up>::value;
829#endif
830
831// is_function
832
833namespace __libcpp_is_function_imp
834{
835struct __dummy_type {};
836template <class _Tp> char  __test(_Tp*);
837template <class _Tp> char __test(__dummy_type);
838template <class _Tp> __two __test(...);
839template <class _Tp> _Tp&  __source(int);
840template <class _Tp> __dummy_type __source(...);
841}
842
843template <class _Tp, bool = is_class<_Tp>::value ||
844                            is_union<_Tp>::value ||
845                            is_void<_Tp>::value  ||
846                            is_reference<_Tp>::value ||
847                            __is_nullptr_t<_Tp>::value >
848struct __libcpp_is_function
849    : public integral_constant<bool, sizeof(__libcpp_is_function_imp::__test<_Tp>(__libcpp_is_function_imp::__source<_Tp>(0))) == 1>
850    {};
851template <class _Tp> struct __libcpp_is_function<_Tp, true> : public false_type {};
852
853template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_function
854    : public __libcpp_is_function<_Tp> {};
855
856#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
857template <class _Tp> _LIBCPP_CONSTEXPR bool is_function_v
858    = is_function<_Tp>::value;
859#endif
860
861// is_member_function_pointer
862
863// template <class _Tp> struct            __libcpp_is_member_function_pointer             : public false_type {};
864// template <class _Tp, class _Up> struct __libcpp_is_member_function_pointer<_Tp _Up::*> : public is_function<_Tp> {};
865//
866
867template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
868struct __member_pointer_traits_imp
869{  // forward declaration; specializations later
870};
871
872
873template <class _Tp> struct __libcpp_is_member_function_pointer
874    : public false_type {};
875
876template <class _Ret, class _Class>
877struct __libcpp_is_member_function_pointer<_Ret _Class::*>
878    : public is_function<_Ret> {};
879
880template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_member_function_pointer
881    : public __libcpp_is_member_function_pointer<typename remove_cv<_Tp>::type>::type {};
882
883#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
884template <class _Tp> _LIBCPP_CONSTEXPR bool is_member_function_pointer_v
885    = is_member_function_pointer<_Tp>::value;
886#endif
887
888// is_member_pointer
889
890template <class _Tp>            struct __libcpp_is_member_pointer             : public false_type {};
891template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> : public true_type {};
892
893template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_member_pointer
894    : public __libcpp_is_member_pointer<typename remove_cv<_Tp>::type> {};
895
896#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
897template <class _Tp> _LIBCPP_CONSTEXPR bool is_member_pointer_v
898    = is_member_pointer<_Tp>::value;
899#endif
900
901// is_member_object_pointer
902
903template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_member_object_pointer
904    : public integral_constant<bool, is_member_pointer<_Tp>::value &&
905                                    !is_member_function_pointer<_Tp>::value> {};
906
907#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
908template <class _Tp> _LIBCPP_CONSTEXPR bool is_member_object_pointer_v
909    = is_member_object_pointer<_Tp>::value;
910#endif
911
912// is_enum
913
914#if __has_feature(is_enum) || (_GNUC_VER >= 403)
915
916template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_enum
917    : public integral_constant<bool, __is_enum(_Tp)> {};
918
919#else
920
921template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_enum
922    : public integral_constant<bool, !is_void<_Tp>::value             &&
923                                     !is_integral<_Tp>::value         &&
924                                     !is_floating_point<_Tp>::value   &&
925                                     !is_array<_Tp>::value            &&
926                                     !is_pointer<_Tp>::value          &&
927                                     !is_reference<_Tp>::value        &&
928                                     !is_member_pointer<_Tp>::value   &&
929                                     !is_union<_Tp>::value            &&
930                                     !is_class<_Tp>::value            &&
931                                     !is_function<_Tp>::value         > {};
932
933#endif
934
935#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
936template <class _Tp> _LIBCPP_CONSTEXPR bool is_enum_v
937    = is_enum<_Tp>::value;
938#endif
939
940// is_arithmetic
941
942template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_arithmetic
943    : public integral_constant<bool, is_integral<_Tp>::value      ||
944                                     is_floating_point<_Tp>::value> {};
945
946#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
947template <class _Tp> _LIBCPP_CONSTEXPR bool is_arithmetic_v
948    = is_arithmetic<_Tp>::value;
949#endif
950
951// is_fundamental
952
953template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_fundamental
954    : public integral_constant<bool, is_void<_Tp>::value        ||
955                                     __is_nullptr_t<_Tp>::value ||
956                                     is_arithmetic<_Tp>::value> {};
957
958#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
959template <class _Tp> _LIBCPP_CONSTEXPR bool is_fundamental_v
960    = is_fundamental<_Tp>::value;
961#endif
962
963// is_scalar
964
965template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_scalar
966    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
967                                     is_member_pointer<_Tp>::value ||
968                                     is_pointer<_Tp>::value        ||
969                                     __is_nullptr_t<_Tp>::value    ||
970                                     is_enum<_Tp>::value           > {};
971
972template <> struct _LIBCPP_TYPE_VIS_ONLY is_scalar<nullptr_t> : public true_type {};
973
974#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
975template <class _Tp> _LIBCPP_CONSTEXPR bool is_scalar_v
976    = is_scalar<_Tp>::value;
977#endif
978
979// is_object
980
981template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_object
982    : public integral_constant<bool, is_scalar<_Tp>::value ||
983                                     is_array<_Tp>::value  ||
984                                     is_union<_Tp>::value  ||
985                                     is_class<_Tp>::value  > {};
986
987#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
988template <class _Tp> _LIBCPP_CONSTEXPR bool is_object_v
989    = is_object<_Tp>::value;
990#endif
991
992// is_compound
993
994template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_compound
995    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
996
997#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
998template <class _Tp> _LIBCPP_CONSTEXPR bool is_compound_v
999    = is_compound<_Tp>::value;
1000#endif
1001
1002
1003// __is_referenceable  [defns.referenceable]
1004
1005struct __is_referenceable_impl {
1006    template <class _Tp> static _Tp& __test(int);
1007    template <class _Tp> static __two __test(...);
1008};
1009
1010template <class _Tp>
1011struct __is_referenceable : integral_constant<bool,
1012    !is_same<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1013
1014
1015// add_const
1016
1017template <class _Tp, bool = is_reference<_Tp>::value ||
1018                            is_function<_Tp>::value  ||
1019                            is_const<_Tp>::value     >
1020struct __add_const             {typedef _Tp type;};
1021
1022template <class _Tp>
1023struct __add_const<_Tp, false> {typedef const _Tp type;};
1024
1025template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_const
1026    {typedef typename __add_const<_Tp>::type type;};
1027
1028#if _LIBCPP_STD_VER > 11
1029template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1030#endif
1031
1032// add_volatile
1033
1034template <class _Tp, bool = is_reference<_Tp>::value ||
1035                            is_function<_Tp>::value  ||
1036                            is_volatile<_Tp>::value  >
1037struct __add_volatile             {typedef _Tp type;};
1038
1039template <class _Tp>
1040struct __add_volatile<_Tp, false> {typedef volatile _Tp type;};
1041
1042template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_volatile
1043    {typedef typename __add_volatile<_Tp>::type type;};
1044
1045#if _LIBCPP_STD_VER > 11
1046template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1047#endif
1048
1049// add_cv
1050
1051template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_cv
1052    {typedef typename add_const<typename add_volatile<_Tp>::type>::type type;};
1053
1054#if _LIBCPP_STD_VER > 11
1055template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1056#endif
1057
1058// remove_reference
1059
1060template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_reference        {typedef _Tp type;};
1061template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_reference<_Tp&>  {typedef _Tp type;};
1062#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1063template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_reference<_Tp&&> {typedef _Tp type;};
1064#endif
1065
1066#if _LIBCPP_STD_VER > 11
1067template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1068#endif
1069
1070// add_lvalue_reference
1071
1072template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _Tp  type; };
1073template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _Tp& type; };
1074
1075template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_lvalue_reference
1076{typedef typename __add_lvalue_reference_impl<_Tp>::type type;};
1077
1078#if _LIBCPP_STD_VER > 11
1079template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1080#endif
1081
1082#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1083
1084template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _Tp   type; };
1085template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _Tp&& type; };
1086
1087template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_rvalue_reference
1088{typedef typename __add_rvalue_reference_impl<_Tp>::type type;};
1089
1090#if _LIBCPP_STD_VER > 11
1091template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1092#endif
1093
1094#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1095
1096#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1097
1098template <class _Tp> _Tp&& __declval(int);
1099template <class _Tp> _Tp   __declval(long);
1100
1101template <class _Tp>
1102decltype(_VSTD::__declval<_Tp>(0))
1103declval() _NOEXCEPT;
1104
1105#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1106
1107template <class _Tp>
1108typename add_lvalue_reference<_Tp>::type
1109declval();
1110
1111#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1112
1113// __uncvref
1114
1115template <class _Tp>
1116struct __uncvref  {
1117    typedef typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1118};
1119
1120template <class _Tp>
1121struct __unconstref {
1122    typedef typename remove_const<typename remove_reference<_Tp>::type>::type type;
1123};
1124
1125#ifndef _LIBCPP_CXX03_LANG
1126template <class _Tp>
1127using __uncvref_t = typename __uncvref<_Tp>::type;
1128#endif
1129
1130// __is_same_uncvref
1131
1132template <class _Tp, class _Up>
1133struct __is_same_uncvref : is_same<typename __uncvref<_Tp>::type,
1134                                   typename __uncvref<_Up>::type> {};
1135
1136struct __any
1137{
1138    __any(...);
1139};
1140
1141// remove_pointer
1142
1143template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_pointer                      {typedef _Tp type;};
1144template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_pointer<_Tp*>                {typedef _Tp type;};
1145template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_pointer<_Tp* const>          {typedef _Tp type;};
1146template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_pointer<_Tp* volatile>       {typedef _Tp type;};
1147template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_pointer<_Tp* const volatile> {typedef _Tp type;};
1148
1149#if _LIBCPP_STD_VER > 11
1150template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1151#endif
1152
1153// add_pointer
1154
1155template <class _Tp,
1156        bool = __is_referenceable<_Tp>::value ||
1157                is_same<typename remove_cv<_Tp>::type, void>::value>
1158struct __add_pointer_impl
1159    {typedef typename remove_reference<_Tp>::type* type;};
1160template <class _Tp> struct __add_pointer_impl<_Tp, false>
1161    {typedef _Tp type;};
1162
1163template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY add_pointer
1164    {typedef typename __add_pointer_impl<_Tp>::type type;};
1165
1166#if _LIBCPP_STD_VER > 11
1167template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1168#endif
1169
1170// is_signed
1171
1172template <class _Tp, bool = is_integral<_Tp>::value>
1173struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1174
1175template <class _Tp>
1176struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1177
1178template <class _Tp, bool = is_arithmetic<_Tp>::value>
1179struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1180
1181template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1182
1183template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_signed : public __libcpp_is_signed<_Tp> {};
1184
1185#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1186template <class _Tp> _LIBCPP_CONSTEXPR bool is_signed_v
1187    = is_signed<_Tp>::value;
1188#endif
1189
1190// is_unsigned
1191
1192template <class _Tp, bool = is_integral<_Tp>::value>
1193struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1194
1195template <class _Tp>
1196struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1197
1198template <class _Tp, bool = is_arithmetic<_Tp>::value>
1199struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1200
1201template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1202
1203template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1204
1205#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1206template <class _Tp> _LIBCPP_CONSTEXPR bool is_unsigned_v
1207    = is_unsigned<_Tp>::value;
1208#endif
1209
1210// rank
1211
1212template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY rank
1213    : public integral_constant<size_t, 0> {};
1214template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY rank<_Tp[]>
1215    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1216template <class _Tp, size_t _Np> struct _LIBCPP_TYPE_VIS_ONLY rank<_Tp[_Np]>
1217    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1218
1219#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1220template <class _Tp> _LIBCPP_CONSTEXPR size_t rank_v
1221    = rank<_Tp>::value;
1222#endif
1223
1224// extent
1225
1226template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TYPE_VIS_ONLY extent
1227    : public integral_constant<size_t, 0> {};
1228template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY extent<_Tp[], 0>
1229    : public integral_constant<size_t, 0> {};
1230template <class _Tp, unsigned _Ip> struct _LIBCPP_TYPE_VIS_ONLY extent<_Tp[], _Ip>
1231    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1232template <class _Tp, size_t _Np> struct _LIBCPP_TYPE_VIS_ONLY extent<_Tp[_Np], 0>
1233    : public integral_constant<size_t, _Np> {};
1234template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TYPE_VIS_ONLY extent<_Tp[_Np], _Ip>
1235    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1236
1237#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1238template <class _Tp, unsigned _Ip = 0> _LIBCPP_CONSTEXPR size_t extent_v
1239    = extent<_Tp, _Ip>::value;
1240#endif
1241
1242// remove_extent
1243
1244template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_extent
1245    {typedef _Tp type;};
1246template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_extent<_Tp[]>
1247    {typedef _Tp type;};
1248template <class _Tp, size_t _Np> struct _LIBCPP_TYPE_VIS_ONLY remove_extent<_Tp[_Np]>
1249    {typedef _Tp type;};
1250
1251#if _LIBCPP_STD_VER > 11
1252template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1253#endif
1254
1255// remove_all_extents
1256
1257template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_all_extents
1258    {typedef _Tp type;};
1259template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY remove_all_extents<_Tp[]>
1260    {typedef typename remove_all_extents<_Tp>::type type;};
1261template <class _Tp, size_t _Np> struct _LIBCPP_TYPE_VIS_ONLY remove_all_extents<_Tp[_Np]>
1262    {typedef typename remove_all_extents<_Tp>::type type;};
1263
1264#if _LIBCPP_STD_VER > 11
1265template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1266#endif
1267
1268// decay
1269
1270template <class _Tp>
1271struct _LIBCPP_TYPE_VIS_ONLY decay
1272{
1273private:
1274    typedef typename remove_reference<_Tp>::type _Up;
1275public:
1276    typedef typename conditional
1277                     <
1278                         is_array<_Up>::value,
1279                         typename remove_extent<_Up>::type*,
1280                         typename conditional
1281                         <
1282                              is_function<_Up>::value,
1283                              typename add_pointer<_Up>::type,
1284                              typename remove_cv<_Up>::type
1285                         >::type
1286                     >::type type;
1287};
1288
1289#if _LIBCPP_STD_VER > 11
1290template <class _Tp> using decay_t = typename decay<_Tp>::type;
1291#endif
1292
1293// is_abstract
1294
1295namespace __is_abstract_imp
1296{
1297template <class _Tp> char  __test(_Tp (*)[1]);
1298template <class _Tp> __two __test(...);
1299}
1300
1301template <class _Tp, bool = is_class<_Tp>::value>
1302struct __libcpp_abstract : public integral_constant<bool, sizeof(__is_abstract_imp::__test<_Tp>(0)) != 1> {};
1303
1304template <class _Tp> struct __libcpp_abstract<_Tp, false> : public false_type {};
1305
1306template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_abstract : public __libcpp_abstract<_Tp> {};
1307
1308#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1309template <class _Tp> _LIBCPP_CONSTEXPR bool is_abstract_v
1310    = is_abstract<_Tp>::value;
1311#endif
1312
1313// is_final
1314
1315#if defined(_LIBCPP_HAS_IS_FINAL)
1316template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY
1317__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1318#else
1319template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY
1320__libcpp_is_final : public false_type {};
1321#endif
1322
1323#if defined(_LIBCPP_HAS_IS_FINAL) && _LIBCPP_STD_VER > 11
1324template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY
1325is_final : public integral_constant<bool, __is_final(_Tp)> {};
1326#endif
1327
1328#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1329template <class _Tp> _LIBCPP_CONSTEXPR bool is_final_v
1330    = is_final<_Tp>::value;
1331#endif
1332
1333// is_base_of
1334
1335#ifdef _LIBCPP_HAS_IS_BASE_OF
1336
1337template <class _Bp, class _Dp>
1338struct _LIBCPP_TYPE_VIS_ONLY is_base_of
1339    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1340
1341#else  // _LIBCPP_HAS_IS_BASE_OF
1342
1343namespace __is_base_of_imp
1344{
1345template <class _Tp>
1346struct _Dst
1347{
1348    _Dst(const volatile _Tp &);
1349};
1350template <class _Tp>
1351struct _Src
1352{
1353    operator const volatile _Tp &();
1354    template <class _Up> operator const _Dst<_Up> &();
1355};
1356template <size_t> struct __one { typedef char type; };
1357template <class _Bp, class _Dp> typename __one<sizeof(_Dst<_Bp>(declval<_Src<_Dp> >()))>::type __test(int);
1358template <class _Bp, class _Dp> __two __test(...);
1359}
1360
1361template <class _Bp, class _Dp>
1362struct _LIBCPP_TYPE_VIS_ONLY is_base_of
1363    : public integral_constant<bool, is_class<_Bp>::value &&
1364                                     sizeof(__is_base_of_imp::__test<_Bp, _Dp>(0)) == 2> {};
1365
1366#endif  // _LIBCPP_HAS_IS_BASE_OF
1367
1368#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1369template <class _Bp, class _Dp> _LIBCPP_CONSTEXPR bool is_base_of_v
1370    = is_base_of<_Bp, _Dp>::value;
1371#endif
1372
1373// is_convertible
1374
1375#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1376
1377template <class _T1, class _T2> struct _LIBCPP_TYPE_VIS_ONLY is_convertible
1378    : public integral_constant<bool, __is_convertible_to(_T1, _T2) &&
1379                                     !is_abstract<_T2>::value> {};
1380
1381#else  // __has_feature(is_convertible_to)
1382
1383namespace __is_convertible_imp
1384{
1385template <class _Tp> void  __test_convert(_Tp);
1386
1387template <class _From, class _To, class = void>
1388struct __is_convertible_test : public false_type {};
1389
1390template <class _From, class _To>
1391struct __is_convertible_test<_From, _To,
1392    decltype(_VSTD::__is_convertible_imp::__test_convert<_To>(_VSTD::declval<_From>()))> : public true_type
1393{};
1394
1395template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1396                     bool _IsFunction = is_function<_Tp>::value,
1397                     bool _IsVoid =     is_void<_Tp>::value>
1398                     struct __is_array_function_or_void                          {enum {value = 0};};
1399template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1400template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1401template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1402}
1403
1404template <class _Tp,
1405    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1406struct __is_convertible_check
1407{
1408    static const size_t __v = 0;
1409};
1410
1411template <class _Tp>
1412struct __is_convertible_check<_Tp, 0>
1413{
1414    static const size_t __v = sizeof(_Tp);
1415};
1416
1417template <class _T1, class _T2,
1418    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1419    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1420struct __is_convertible
1421    : public integral_constant<bool,
1422        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1423#if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
1424         && !(!is_function<_T1>::value && !is_reference<_T1>::value && is_reference<_T2>::value
1425              && (!is_const<typename remove_reference<_T2>::type>::value
1426                  || is_volatile<typename remove_reference<_T2>::type>::value)
1427                  && (is_same<typename remove_cv<_T1>::type,
1428                              typename remove_cv<typename remove_reference<_T2>::type>::type>::value
1429                      || is_base_of<typename remove_reference<_T2>::type, _T1>::value))
1430#endif
1431    >
1432{};
1433
1434template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1435template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1436template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1437template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1438
1439template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1440template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1441template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1442template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1443
1444template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1445template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1446template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1447template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1448
1449template <class _T1, class _T2> struct _LIBCPP_TYPE_VIS_ONLY is_convertible
1450    : public __is_convertible<_T1, _T2>
1451{
1452    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1453    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1454};
1455
1456#endif  // __has_feature(is_convertible_to)
1457
1458#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1459template <class _From, class _To> _LIBCPP_CONSTEXPR bool is_convertible_v
1460    = is_convertible<_From, _To>::value;
1461#endif
1462
1463// is_empty
1464
1465#if __has_feature(is_empty) || (_GNUC_VER >= 407)
1466
1467template <class _Tp>
1468struct _LIBCPP_TYPE_VIS_ONLY is_empty
1469    : public integral_constant<bool, __is_empty(_Tp)> {};
1470
1471#else  // __has_feature(is_empty)
1472
1473template <class _Tp>
1474struct __is_empty1
1475    : public _Tp
1476{
1477    double __lx;
1478};
1479
1480struct __is_empty2
1481{
1482    double __lx;
1483};
1484
1485template <class _Tp, bool = is_class<_Tp>::value>
1486struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1487
1488template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1489
1490template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_empty : public __libcpp_empty<_Tp> {};
1491
1492#endif  // __has_feature(is_empty)
1493
1494#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1495template <class _Tp> _LIBCPP_CONSTEXPR bool is_empty_v
1496    = is_empty<_Tp>::value;
1497#endif
1498
1499// is_polymorphic
1500
1501#if __has_feature(is_polymorphic) || defined(_LIBCPP_MSVC)
1502
1503template <class _Tp>
1504struct _LIBCPP_TYPE_VIS_ONLY is_polymorphic
1505    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1506
1507#else
1508
1509template<typename _Tp> char &__is_polymorphic_impl(
1510    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1511                       int>::type);
1512template<typename _Tp> __two &__is_polymorphic_impl(...);
1513
1514template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_polymorphic
1515    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1516
1517#endif // __has_feature(is_polymorphic)
1518
1519#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1520template <class _Tp> _LIBCPP_CONSTEXPR bool is_polymorphic_v
1521    = is_polymorphic<_Tp>::value;
1522#endif
1523
1524// has_virtual_destructor
1525
1526#if __has_feature(has_virtual_destructor) || (_GNUC_VER >= 403)
1527
1528template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY has_virtual_destructor
1529    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1530
1531#else
1532
1533template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY has_virtual_destructor
1534    : public false_type {};
1535
1536#endif
1537
1538#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1539template <class _Tp> _LIBCPP_CONSTEXPR bool has_virtual_destructor_v
1540    = has_virtual_destructor<_Tp>::value;
1541#endif
1542
1543// alignment_of
1544
1545template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY alignment_of
1546    : public integral_constant<size_t, __alignof__(_Tp)> {};
1547
1548#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
1549template <class _Tp> _LIBCPP_CONSTEXPR size_t alignment_of_v
1550    = alignment_of<_Tp>::value;
1551#endif
1552
1553// aligned_storage
1554
1555template <class _Hp, class _Tp>
1556struct __type_list
1557{
1558    typedef _Hp _Head;
1559    typedef _Tp _Tail;
1560};
1561
1562struct __nat
1563{
1564#ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
1565    __nat() = delete;
1566    __nat(const __nat&) = delete;
1567    __nat& operator=(const __nat&) = delete;
1568    ~__nat() = delete;
1569#endif
1570};
1571
1572template <class _Tp>
1573struct __align_type
1574{
1575    static const size_t value = alignment_of<_Tp>::value;
1576    typedef _Tp type;
1577};
1578
1579struct __struct_double {long double __lx;};
1580struct __struct_double4 {double __lx[4];};
1581
1582typedef
1583    __type_list<__align_type<unsigned char>,
1584    __type_list<__align_type<unsigned short>,
1585    __type_list<__align_type<unsigned int>,
1586    __type_list<__align_type<unsigned long>,
1587    __type_list<__align_type<unsigned long long>,
1588    __type_list<__align_type<double>,
1589    __type_list<__align_type<long double>,
1590    __type_list<__align_type<__struct_double>,
1591    __type_list<__align_type<__struct_double4>,
1592    __type_list<__align_type<int*>,
1593    __nat
1594    > > > > > > > > > > __all_types;
1595
1596template <class _TL, size_t _Align> struct __find_pod;
1597
1598template <class _Hp, size_t _Align>
1599struct __find_pod<__type_list<_Hp, __nat>, _Align>
1600{
1601    typedef typename conditional<
1602                             _Align == _Hp::value,
1603                             typename _Hp::type,
1604                             void
1605                         >::type type;
1606};
1607
1608template <class _Hp, class _Tp, size_t _Align>
1609struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1610{
1611    typedef typename conditional<
1612                             _Align == _Hp::value,
1613                             typename _Hp::type,
1614                             typename __find_pod<_Tp, _Align>::type
1615                         >::type type;
1616};
1617
1618template <class _TL, size_t _Len> struct __find_max_align;
1619
1620template <class _Hp, size_t _Len>
1621struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
1622
1623template <size_t _Len, size_t _A1, size_t _A2>
1624struct __select_align
1625{
1626private:
1627    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
1628    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
1629public:
1630    static const size_t value = _Len < __max ? __min : __max;
1631};
1632
1633template <class _Hp, class _Tp, size_t _Len>
1634struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
1635    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
1636
1637template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1638struct _LIBCPP_TYPE_VIS_ONLY aligned_storage
1639{
1640    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
1641    static_assert(!is_void<_Aligner>::value, "");
1642    union type
1643    {
1644        _Aligner __align;
1645        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
1646    };
1647};
1648
1649#if _LIBCPP_STD_VER > 11
1650template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1651    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
1652#endif
1653
1654#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
1655template <size_t _Len>\
1656struct _LIBCPP_TYPE_VIS_ONLY aligned_storage<_Len, n>\
1657{\
1658    struct _ALIGNAS(n) type\
1659    {\
1660        unsigned char __lx[(_Len + n - 1)/n * n];\
1661    };\
1662}
1663
1664_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
1665_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
1666_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
1667_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
1668_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
1669_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
1670_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
1671_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
1672_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
1673_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
1674_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
1675_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
1676_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
1677_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
1678// PE/COFF does not support alignment beyond 8192 (=0x2000)
1679#if !defined(_WIN32)
1680_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
1681#endif // !_WIN32
1682
1683#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
1684
1685#ifndef _LIBCPP_HAS_NO_VARIADICS
1686
1687// aligned_union
1688
1689template <size_t _I0, size_t ..._In>
1690struct __static_max;
1691
1692template <size_t _I0>
1693struct __static_max<_I0>
1694{
1695    static const size_t value = _I0;
1696};
1697
1698template <size_t _I0, size_t _I1, size_t ..._In>
1699struct __static_max<_I0, _I1, _In...>
1700{
1701    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
1702                                             __static_max<_I1, _In...>::value;
1703};
1704
1705template <size_t _Len, class _Type0, class ..._Types>
1706struct aligned_union
1707{
1708    static const size_t alignment_value = __static_max<__alignof__(_Type0),
1709                                                       __alignof__(_Types)...>::value;
1710    static const size_t __len = __static_max<_Len, sizeof(_Type0),
1711                                             sizeof(_Types)...>::value;
1712    typedef typename aligned_storage<__len, alignment_value>::type type;
1713};
1714
1715#if _LIBCPP_STD_VER > 11
1716template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
1717#endif
1718
1719#endif  // _LIBCPP_HAS_NO_VARIADICS
1720
1721template <class _Tp>
1722struct __numeric_type
1723{
1724   static void __test(...);
1725   static float __test(float);
1726   static double __test(char);
1727   static double __test(int);
1728   static double __test(unsigned);
1729   static double __test(long);
1730   static double __test(unsigned long);
1731   static double __test(long long);
1732   static double __test(unsigned long long);
1733   static double __test(double);
1734   static long double __test(long double);
1735
1736   typedef decltype(__test(declval<_Tp>())) type;
1737   static const bool value = !is_same<type, void>::value;
1738};
1739
1740template <>
1741struct __numeric_type<void>
1742{
1743   static const bool value = true;
1744};
1745
1746// __promote
1747
1748template <class _A1, class _A2 = void, class _A3 = void,
1749          bool = __numeric_type<_A1>::value &&
1750                 __numeric_type<_A2>::value &&
1751                 __numeric_type<_A3>::value>
1752class __promote_imp
1753{
1754public:
1755    static const bool value = false;
1756};
1757
1758template <class _A1, class _A2, class _A3>
1759class __promote_imp<_A1, _A2, _A3, true>
1760{
1761private:
1762    typedef typename __promote_imp<_A1>::type __type1;
1763    typedef typename __promote_imp<_A2>::type __type2;
1764    typedef typename __promote_imp<_A3>::type __type3;
1765public:
1766    typedef decltype(__type1() + __type2() + __type3()) type;
1767    static const bool value = true;
1768};
1769
1770template <class _A1, class _A2>
1771class __promote_imp<_A1, _A2, void, true>
1772{
1773private:
1774    typedef typename __promote_imp<_A1>::type __type1;
1775    typedef typename __promote_imp<_A2>::type __type2;
1776public:
1777    typedef decltype(__type1() + __type2()) type;
1778    static const bool value = true;
1779};
1780
1781template <class _A1>
1782class __promote_imp<_A1, void, void, true>
1783{
1784public:
1785    typedef typename __numeric_type<_A1>::type type;
1786    static const bool value = true;
1787};
1788
1789template <class _A1, class _A2 = void, class _A3 = void>
1790class __promote : public __promote_imp<_A1, _A2, _A3> {};
1791
1792// make_signed / make_unsigned
1793
1794typedef
1795    __type_list<signed char,
1796    __type_list<signed short,
1797    __type_list<signed int,
1798    __type_list<signed long,
1799    __type_list<signed long long,
1800#ifndef _LIBCPP_HAS_NO_INT128
1801    __type_list<__int128_t,
1802#endif
1803    __nat
1804#ifndef _LIBCPP_HAS_NO_INT128
1805    >
1806#endif
1807    > > > > > __signed_types;
1808
1809typedef
1810    __type_list<unsigned char,
1811    __type_list<unsigned short,
1812    __type_list<unsigned int,
1813    __type_list<unsigned long,
1814    __type_list<unsigned long long,
1815#ifndef _LIBCPP_HAS_NO_INT128
1816    __type_list<__uint128_t,
1817#endif
1818    __nat
1819#ifndef _LIBCPP_HAS_NO_INT128
1820    >
1821#endif
1822    > > > > > __unsigned_types;
1823
1824template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
1825
1826template <class _Hp, class _Tp, size_t _Size>
1827struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
1828{
1829    typedef _Hp type;
1830};
1831
1832template <class _Hp, class _Tp, size_t _Size>
1833struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
1834{
1835    typedef typename __find_first<_Tp, _Size>::type type;
1836};
1837
1838template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
1839                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
1840struct __apply_cv
1841{
1842    typedef _Up type;
1843};
1844
1845template <class _Tp, class _Up>
1846struct __apply_cv<_Tp, _Up, true, false>
1847{
1848    typedef const _Up type;
1849};
1850
1851template <class _Tp, class _Up>
1852struct __apply_cv<_Tp, _Up, false, true>
1853{
1854    typedef volatile _Up type;
1855};
1856
1857template <class _Tp, class _Up>
1858struct __apply_cv<_Tp, _Up, true, true>
1859{
1860    typedef const volatile _Up type;
1861};
1862
1863template <class _Tp, class _Up>
1864struct __apply_cv<_Tp&, _Up, false, false>
1865{
1866    typedef _Up& type;
1867};
1868
1869template <class _Tp, class _Up>
1870struct __apply_cv<_Tp&, _Up, true, false>
1871{
1872    typedef const _Up& type;
1873};
1874
1875template <class _Tp, class _Up>
1876struct __apply_cv<_Tp&, _Up, false, true>
1877{
1878    typedef volatile _Up& type;
1879};
1880
1881template <class _Tp, class _Up>
1882struct __apply_cv<_Tp&, _Up, true, true>
1883{
1884    typedef const volatile _Up& type;
1885};
1886
1887template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
1888struct __make_signed {};
1889
1890template <class _Tp>
1891struct __make_signed<_Tp, true>
1892{
1893    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
1894};
1895
1896template <> struct __make_signed<bool,               true> {};
1897template <> struct __make_signed<  signed short,     true> {typedef short     type;};
1898template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
1899template <> struct __make_signed<  signed int,       true> {typedef int       type;};
1900template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
1901template <> struct __make_signed<  signed long,      true> {typedef long      type;};
1902template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
1903template <> struct __make_signed<  signed long long, true> {typedef long long type;};
1904template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
1905#ifndef _LIBCPP_HAS_NO_INT128
1906template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
1907template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
1908#endif
1909
1910template <class _Tp>
1911struct _LIBCPP_TYPE_VIS_ONLY make_signed
1912{
1913    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
1914};
1915
1916#if _LIBCPP_STD_VER > 11
1917template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
1918#endif
1919
1920template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
1921struct __make_unsigned {};
1922
1923template <class _Tp>
1924struct __make_unsigned<_Tp, true>
1925{
1926    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
1927};
1928
1929template <> struct __make_unsigned<bool,               true> {};
1930template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
1931template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
1932template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
1933template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
1934template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
1935template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
1936template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
1937template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
1938#ifndef _LIBCPP_HAS_NO_INT128
1939template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
1940template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
1941#endif
1942
1943template <class _Tp>
1944struct _LIBCPP_TYPE_VIS_ONLY make_unsigned
1945{
1946    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
1947};
1948
1949#if _LIBCPP_STD_VER > 11
1950template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
1951#endif
1952
1953#ifdef _LIBCPP_HAS_NO_VARIADICS
1954
1955template <class _Tp, class _Up = void, class _Vp = void>
1956struct _LIBCPP_TYPE_VIS_ONLY common_type
1957{
1958public:
1959    typedef typename common_type<typename common_type<_Tp, _Up>::type, _Vp>::type type;
1960};
1961
1962template <class _Tp>
1963struct _LIBCPP_TYPE_VIS_ONLY common_type<_Tp, void, void>
1964{
1965public:
1966    typedef typename decay<_Tp>::type type;
1967};
1968
1969template <class _Tp, class _Up>
1970struct _LIBCPP_TYPE_VIS_ONLY common_type<_Tp, _Up, void>
1971{
1972    typedef typename decay<decltype(
1973        true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
1974      )>::type type;
1975};
1976
1977#else  // _LIBCPP_HAS_NO_VARIADICS
1978
1979// bullet 1 - sizeof...(Tp) == 0
1980
1981template <class ..._Tp>
1982struct _LIBCPP_TYPE_VIS_ONLY common_type {};
1983
1984// bullet 2 - sizeof...(Tp) == 1
1985
1986template <class _Tp>
1987struct _LIBCPP_TYPE_VIS_ONLY common_type<_Tp>
1988{
1989    typedef typename decay<_Tp>::type type;
1990};
1991
1992// bullet 3 - sizeof...(Tp) == 2
1993
1994template <class _Tp, class _Up, class = void>
1995struct __common_type2 {};
1996
1997template <class _Tp, class _Up>
1998struct __common_type2<_Tp, _Up,
1999    typename __void_t<decltype(
2000        true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2001    )>::type>
2002{
2003    typedef typename decay<decltype(
2004        true ? _VSTD::declval<_Tp>() : _VSTD::declval<_Up>()
2005    )>::type type;
2006};
2007
2008template <class _Tp, class _Up>
2009struct _LIBCPP_TYPE_VIS_ONLY common_type<_Tp, _Up>
2010    : __common_type2<_Tp, _Up> {};
2011
2012// bullet 4 - sizeof...(Tp) > 2
2013
2014template <class ...Tp> struct __common_types;
2015
2016template <class, class = void>
2017struct __common_type_impl {};
2018
2019template <class _Tp, class _Up, class ..._Vp>
2020struct __common_type_impl<__common_types<_Tp, _Up, _Vp...>,
2021    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2022{
2023    typedef typename common_type<
2024        typename common_type<_Tp, _Up>::type, _Vp...
2025    >::type type;
2026};
2027
2028template <class _Tp, class _Up, class ..._Vp>
2029struct _LIBCPP_TYPE_VIS_ONLY common_type<_Tp, _Up, _Vp...>
2030    : __common_type_impl<__common_types<_Tp, _Up, _Vp...> > {};
2031
2032#if _LIBCPP_STD_VER > 11
2033template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2034#endif
2035
2036#endif  // _LIBCPP_HAS_NO_VARIADICS
2037
2038// is_assignable
2039
2040template<typename, typename _Tp> struct __select_2nd { typedef _Tp type; };
2041
2042template <class _Tp, class _Arg>
2043typename __select_2nd<decltype((_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>())), true_type>::type
2044__is_assignable_test(int);
2045
2046template <class, class>
2047false_type __is_assignable_test(...);
2048
2049
2050template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2051struct __is_assignable_imp
2052    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2053
2054template <class _Tp, class _Arg>
2055struct __is_assignable_imp<_Tp, _Arg, true>
2056    : public false_type
2057{
2058};
2059
2060template <class _Tp, class _Arg>
2061struct is_assignable
2062    : public __is_assignable_imp<_Tp, _Arg> {};
2063
2064#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2065template <class _Tp, class _Arg> _LIBCPP_CONSTEXPR bool is_assignable_v
2066    = is_assignable<_Tp, _Arg>::value;
2067#endif
2068
2069// is_copy_assignable
2070
2071template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_copy_assignable
2072    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2073                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2074
2075#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2076template <class _Tp> _LIBCPP_CONSTEXPR bool is_copy_assignable_v
2077    = is_copy_assignable<_Tp>::value;
2078#endif
2079
2080// is_move_assignable
2081
2082template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_move_assignable
2083#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2084    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2085                     const typename add_rvalue_reference<_Tp>::type> {};
2086#else
2087    : public is_copy_assignable<_Tp> {};
2088#endif
2089
2090#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2091template <class _Tp> _LIBCPP_CONSTEXPR bool is_move_assignable_v
2092    = is_move_assignable<_Tp>::value;
2093#endif
2094
2095// is_destructible
2096
2097//  if it's a reference, return true
2098//  if it's a function, return false
2099//  if it's   void,     return false
2100//  if it's an array of unknown bound, return false
2101//  Otherwise, return "std::declval<_Up&>().~_Up()" is well-formed
2102//    where _Up is remove_all_extents<_Tp>::type
2103
2104template <class>
2105struct __is_destructible_apply { typedef int type; };
2106
2107template <typename _Tp>
2108struct __is_destructor_wellformed {
2109    template <typename _Tp1>
2110    static char  __test (
2111        typename __is_destructible_apply<decltype(_VSTD::declval<_Tp1&>().~_Tp1())>::type
2112    );
2113
2114    template <typename _Tp1>
2115    static __two __test (...);
2116
2117    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2118};
2119
2120template <class _Tp, bool>
2121struct __destructible_imp;
2122
2123template <class _Tp>
2124struct __destructible_imp<_Tp, false>
2125   : public _VSTD::integral_constant<bool,
2126        __is_destructor_wellformed<typename _VSTD::remove_all_extents<_Tp>::type>::value> {};
2127
2128template <class _Tp>
2129struct __destructible_imp<_Tp, true>
2130    : public _VSTD::true_type {};
2131
2132template <class _Tp, bool>
2133struct __destructible_false;
2134
2135template <class _Tp>
2136struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, _VSTD::is_reference<_Tp>::value> {};
2137
2138template <class _Tp>
2139struct __destructible_false<_Tp, true> : public _VSTD::false_type {};
2140
2141template <class _Tp>
2142struct is_destructible
2143    : public __destructible_false<_Tp, _VSTD::is_function<_Tp>::value> {};
2144
2145template <class _Tp>
2146struct is_destructible<_Tp[]>
2147    : public _VSTD::false_type {};
2148
2149template <>
2150struct is_destructible<void>
2151    : public _VSTD::false_type {};
2152
2153#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
2154template <class _Tp> _LIBCPP_CONSTEXPR bool is_destructible_v
2155    = is_destructible<_Tp>::value;
2156#endif
2157
2158// move
2159
2160#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2161
2162template <class _Tp>
2163inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2164typename remove_reference<_Tp>::type&&
2165move(_Tp&& __t) _NOEXCEPT
2166{
2167    typedef typename remove_reference<_Tp>::type _Up;
2168    return static_cast<_Up&&>(__t);
2169}
2170
2171template <class _Tp>
2172inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2173_Tp&&
2174forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT
2175{
2176    return static_cast<_Tp&&>(__t);
2177}
2178
2179template <class _Tp>
2180inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2181_Tp&&
2182forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT
2183{
2184    static_assert(!is_lvalue_reference<_Tp>::value,
2185                  "can not forward an rvalue as an lvalue");
2186    return static_cast<_Tp&&>(__t);
2187}
2188
2189#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2190
2191template <class _Tp>
2192inline _LIBCPP_INLINE_VISIBILITY
2193_Tp&
2194move(_Tp& __t)
2195{
2196    return __t;
2197}
2198
2199template <class _Tp>
2200inline _LIBCPP_INLINE_VISIBILITY
2201const _Tp&
2202move(const _Tp& __t)
2203{
2204    return __t;
2205}
2206
2207template <class _Tp>
2208inline _LIBCPP_INLINE_VISIBILITY
2209_Tp&
2210forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT
2211{
2212    return __t;
2213}
2214
2215
2216template <class _Tp>
2217class __rv
2218{
2219    typedef typename remove_reference<_Tp>::type _Trr;
2220    _Trr& t_;
2221public:
2222    _LIBCPP_INLINE_VISIBILITY
2223    _Trr* operator->() {return &t_;}
2224    _LIBCPP_INLINE_VISIBILITY
2225    explicit __rv(_Trr& __t) : t_(__t) {}
2226};
2227
2228#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2229
2230#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2231
2232template <class _Tp>
2233inline _LIBCPP_INLINE_VISIBILITY
2234typename decay<_Tp>::type
2235__decay_copy(_Tp&& __t)
2236{
2237    return _VSTD::forward<_Tp>(__t);
2238}
2239
2240#else
2241
2242template <class _Tp>
2243inline _LIBCPP_INLINE_VISIBILITY
2244typename decay<_Tp>::type
2245__decay_copy(const _Tp& __t)
2246{
2247    return _VSTD::forward<_Tp>(__t);
2248}
2249
2250#endif
2251
2252#ifndef _LIBCPP_HAS_NO_VARIADICS
2253
2254template <class _Rp, class _Class, class ..._Param>
2255struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2256{
2257    typedef _Class _ClassType;
2258    typedef _Rp _ReturnType;
2259    typedef _Rp (_FnType) (_Param...);
2260};
2261
2262template <class _Rp, class _Class, class ..._Param>
2263struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2264{
2265    typedef _Class _ClassType;
2266    typedef _Rp _ReturnType;
2267    typedef _Rp (_FnType) (_Param..., ...);
2268};
2269
2270template <class _Rp, class _Class, class ..._Param>
2271struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2272{
2273    typedef _Class const _ClassType;
2274    typedef _Rp _ReturnType;
2275    typedef _Rp (_FnType) (_Param...);
2276};
2277
2278template <class _Rp, class _Class, class ..._Param>
2279struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2280{
2281    typedef _Class const _ClassType;
2282    typedef _Rp _ReturnType;
2283    typedef _Rp (_FnType) (_Param..., ...);
2284};
2285
2286template <class _Rp, class _Class, class ..._Param>
2287struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2288{
2289    typedef _Class volatile _ClassType;
2290    typedef _Rp _ReturnType;
2291    typedef _Rp (_FnType) (_Param...);
2292};
2293
2294template <class _Rp, class _Class, class ..._Param>
2295struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2296{
2297    typedef _Class volatile _ClassType;
2298    typedef _Rp _ReturnType;
2299    typedef _Rp (_FnType) (_Param..., ...);
2300};
2301
2302template <class _Rp, class _Class, class ..._Param>
2303struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2304{
2305    typedef _Class const volatile _ClassType;
2306    typedef _Rp _ReturnType;
2307    typedef _Rp (_FnType) (_Param...);
2308};
2309
2310template <class _Rp, class _Class, class ..._Param>
2311struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2312{
2313    typedef _Class const volatile _ClassType;
2314    typedef _Rp _ReturnType;
2315    typedef _Rp (_FnType) (_Param..., ...);
2316};
2317
2318#if __has_feature(cxx_reference_qualified_functions) || \
2319    (defined(_GNUC_VER) && _GNUC_VER >= 409)
2320
2321template <class _Rp, class _Class, class ..._Param>
2322struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2323{
2324    typedef _Class& _ClassType;
2325    typedef _Rp _ReturnType;
2326    typedef _Rp (_FnType) (_Param...);
2327};
2328
2329template <class _Rp, class _Class, class ..._Param>
2330struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2331{
2332    typedef _Class& _ClassType;
2333    typedef _Rp _ReturnType;
2334    typedef _Rp (_FnType) (_Param..., ...);
2335};
2336
2337template <class _Rp, class _Class, class ..._Param>
2338struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2339{
2340    typedef _Class const& _ClassType;
2341    typedef _Rp _ReturnType;
2342    typedef _Rp (_FnType) (_Param...);
2343};
2344
2345template <class _Rp, class _Class, class ..._Param>
2346struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2347{
2348    typedef _Class const& _ClassType;
2349    typedef _Rp _ReturnType;
2350    typedef _Rp (_FnType) (_Param..., ...);
2351};
2352
2353template <class _Rp, class _Class, class ..._Param>
2354struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2355{
2356    typedef _Class volatile& _ClassType;
2357    typedef _Rp _ReturnType;
2358    typedef _Rp (_FnType) (_Param...);
2359};
2360
2361template <class _Rp, class _Class, class ..._Param>
2362struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2363{
2364    typedef _Class volatile& _ClassType;
2365    typedef _Rp _ReturnType;
2366    typedef _Rp (_FnType) (_Param..., ...);
2367};
2368
2369template <class _Rp, class _Class, class ..._Param>
2370struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2371{
2372    typedef _Class const volatile& _ClassType;
2373    typedef _Rp _ReturnType;
2374    typedef _Rp (_FnType) (_Param...);
2375};
2376
2377template <class _Rp, class _Class, class ..._Param>
2378struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2379{
2380    typedef _Class const volatile& _ClassType;
2381    typedef _Rp _ReturnType;
2382    typedef _Rp (_FnType) (_Param..., ...);
2383};
2384
2385template <class _Rp, class _Class, class ..._Param>
2386struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2387{
2388    typedef _Class&& _ClassType;
2389    typedef _Rp _ReturnType;
2390    typedef _Rp (_FnType) (_Param...);
2391};
2392
2393template <class _Rp, class _Class, class ..._Param>
2394struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2395{
2396    typedef _Class&& _ClassType;
2397    typedef _Rp _ReturnType;
2398    typedef _Rp (_FnType) (_Param..., ...);
2399};
2400
2401template <class _Rp, class _Class, class ..._Param>
2402struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2403{
2404    typedef _Class const&& _ClassType;
2405    typedef _Rp _ReturnType;
2406    typedef _Rp (_FnType) (_Param...);
2407};
2408
2409template <class _Rp, class _Class, class ..._Param>
2410struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2411{
2412    typedef _Class const&& _ClassType;
2413    typedef _Rp _ReturnType;
2414    typedef _Rp (_FnType) (_Param..., ...);
2415};
2416
2417template <class _Rp, class _Class, class ..._Param>
2418struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2419{
2420    typedef _Class volatile&& _ClassType;
2421    typedef _Rp _ReturnType;
2422    typedef _Rp (_FnType) (_Param...);
2423};
2424
2425template <class _Rp, class _Class, class ..._Param>
2426struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2427{
2428    typedef _Class volatile&& _ClassType;
2429    typedef _Rp _ReturnType;
2430    typedef _Rp (_FnType) (_Param..., ...);
2431};
2432
2433template <class _Rp, class _Class, class ..._Param>
2434struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2435{
2436    typedef _Class const volatile&& _ClassType;
2437    typedef _Rp _ReturnType;
2438    typedef _Rp (_FnType) (_Param...);
2439};
2440
2441template <class _Rp, class _Class, class ..._Param>
2442struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2443{
2444    typedef _Class const volatile&& _ClassType;
2445    typedef _Rp _ReturnType;
2446    typedef _Rp (_FnType) (_Param..., ...);
2447};
2448
2449#endif  // __has_feature(cxx_reference_qualified_functions) || _GNUC_VER >= 409
2450
2451#else  // _LIBCPP_HAS_NO_VARIADICS
2452
2453template <class _Rp, class _Class>
2454struct __member_pointer_traits_imp<_Rp (_Class::*)(), true, false>
2455{
2456    typedef _Class _ClassType;
2457    typedef _Rp _ReturnType;
2458    typedef _Rp (_FnType) ();
2459};
2460
2461template <class _Rp, class _Class>
2462struct __member_pointer_traits_imp<_Rp (_Class::*)(...), true, false>
2463{
2464    typedef _Class _ClassType;
2465    typedef _Rp _ReturnType;
2466    typedef _Rp (_FnType) (...);
2467};
2468
2469template <class _Rp, class _Class, class _P0>
2470struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0), true, false>
2471{
2472    typedef _Class _ClassType;
2473    typedef _Rp _ReturnType;
2474    typedef _Rp (_FnType) (_P0);
2475};
2476
2477template <class _Rp, class _Class, class _P0>
2478struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, ...), true, false>
2479{
2480    typedef _Class _ClassType;
2481    typedef _Rp _ReturnType;
2482    typedef _Rp (_FnType) (_P0, ...);
2483};
2484
2485template <class _Rp, class _Class, class _P0, class _P1>
2486struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1), true, false>
2487{
2488    typedef _Class _ClassType;
2489    typedef _Rp _ReturnType;
2490    typedef _Rp (_FnType) (_P0, _P1);
2491};
2492
2493template <class _Rp, class _Class, class _P0, class _P1>
2494struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, ...), true, false>
2495{
2496    typedef _Class _ClassType;
2497    typedef _Rp _ReturnType;
2498    typedef _Rp (_FnType) (_P0, _P1, ...);
2499};
2500
2501template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2502struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2), true, false>
2503{
2504    typedef _Class _ClassType;
2505    typedef _Rp _ReturnType;
2506    typedef _Rp (_FnType) (_P0, _P1, _P2);
2507};
2508
2509template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2510struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2, ...), true, false>
2511{
2512    typedef _Class _ClassType;
2513    typedef _Rp _ReturnType;
2514    typedef _Rp (_FnType) (_P0, _P1, _P2, ...);
2515};
2516
2517template <class _Rp, class _Class>
2518struct __member_pointer_traits_imp<_Rp (_Class::*)() const, true, false>
2519{
2520    typedef _Class const _ClassType;
2521    typedef _Rp _ReturnType;
2522    typedef _Rp (_FnType) ();
2523};
2524
2525template <class _Rp, class _Class>
2526struct __member_pointer_traits_imp<_Rp (_Class::*)(...) const, true, false>
2527{
2528    typedef _Class const _ClassType;
2529    typedef _Rp _ReturnType;
2530    typedef _Rp (_FnType) (...);
2531};
2532
2533template <class _Rp, class _Class, class _P0>
2534struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0) const, true, false>
2535{
2536    typedef _Class const _ClassType;
2537    typedef _Rp _ReturnType;
2538    typedef _Rp (_FnType) (_P0);
2539};
2540
2541template <class _Rp, class _Class, class _P0>
2542struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, ...) const, true, false>
2543{
2544    typedef _Class const _ClassType;
2545    typedef _Rp _ReturnType;
2546    typedef _Rp (_FnType) (_P0, ...);
2547};
2548
2549template <class _Rp, class _Class, class _P0, class _P1>
2550struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1) const, true, false>
2551{
2552    typedef _Class const _ClassType;
2553    typedef _Rp _ReturnType;
2554    typedef _Rp (_FnType) (_P0, _P1);
2555};
2556
2557template <class _Rp, class _Class, class _P0, class _P1>
2558struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, ...) const, true, false>
2559{
2560    typedef _Class const _ClassType;
2561    typedef _Rp _ReturnType;
2562    typedef _Rp (_FnType) (_P0, _P1, ...);
2563};
2564
2565template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2566struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2) const, true, false>
2567{
2568    typedef _Class const _ClassType;
2569    typedef _Rp _ReturnType;
2570    typedef _Rp (_FnType) (_P0, _P1, _P2);
2571};
2572
2573template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2574struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2, ...) const, true, false>
2575{
2576    typedef _Class const _ClassType;
2577    typedef _Rp _ReturnType;
2578    typedef _Rp (_FnType) (_P0, _P1, _P2, ...);
2579};
2580
2581template <class _Rp, class _Class>
2582struct __member_pointer_traits_imp<_Rp (_Class::*)() volatile, true, false>
2583{
2584    typedef _Class volatile _ClassType;
2585    typedef _Rp _ReturnType;
2586    typedef _Rp (_FnType) ();
2587};
2588
2589template <class _Rp, class _Class>
2590struct __member_pointer_traits_imp<_Rp (_Class::*)(...) volatile, true, false>
2591{
2592    typedef _Class volatile _ClassType;
2593    typedef _Rp _ReturnType;
2594    typedef _Rp (_FnType) (...);
2595};
2596
2597template <class _Rp, class _Class, class _P0>
2598struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0) volatile, true, false>
2599{
2600    typedef _Class volatile _ClassType;
2601    typedef _Rp _ReturnType;
2602    typedef _Rp (_FnType) (_P0);
2603};
2604
2605template <class _Rp, class _Class, class _P0>
2606struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, ...) volatile, true, false>
2607{
2608    typedef _Class volatile _ClassType;
2609    typedef _Rp _ReturnType;
2610    typedef _Rp (_FnType) (_P0, ...);
2611};
2612
2613template <class _Rp, class _Class, class _P0, class _P1>
2614struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1) volatile, true, false>
2615{
2616    typedef _Class volatile _ClassType;
2617    typedef _Rp _ReturnType;
2618    typedef _Rp (_FnType) (_P0, _P1);
2619};
2620
2621template <class _Rp, class _Class, class _P0, class _P1>
2622struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, ...) volatile, true, false>
2623{
2624    typedef _Class volatile _ClassType;
2625    typedef _Rp _ReturnType;
2626    typedef _Rp (_FnType) (_P0, _P1, ...);
2627};
2628
2629template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2630struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2) volatile, true, false>
2631{
2632    typedef _Class volatile _ClassType;
2633    typedef _Rp _ReturnType;
2634    typedef _Rp (_FnType) (_P0, _P1, _P2);
2635};
2636
2637template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2638struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2, ...) volatile, true, false>
2639{
2640    typedef _Class volatile _ClassType;
2641    typedef _Rp _ReturnType;
2642    typedef _Rp (_FnType) (_P0, _P1, _P2, ...);
2643};
2644
2645template <class _Rp, class _Class>
2646struct __member_pointer_traits_imp<_Rp (_Class::*)() const volatile, true, false>
2647{
2648    typedef _Class const volatile _ClassType;
2649    typedef _Rp _ReturnType;
2650    typedef _Rp (_FnType) ();
2651};
2652
2653template <class _Rp, class _Class>
2654struct __member_pointer_traits_imp<_Rp (_Class::*)(...) const volatile, true, false>
2655{
2656    typedef _Class const volatile _ClassType;
2657    typedef _Rp _ReturnType;
2658    typedef _Rp (_FnType) (...);
2659};
2660
2661template <class _Rp, class _Class, class _P0>
2662struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0) const volatile, true, false>
2663{
2664    typedef _Class const volatile _ClassType;
2665    typedef _Rp _ReturnType;
2666    typedef _Rp (_FnType) (_P0);
2667};
2668
2669template <class _Rp, class _Class, class _P0>
2670struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, ...) const volatile, true, false>
2671{
2672    typedef _Class const volatile _ClassType;
2673    typedef _Rp _ReturnType;
2674    typedef _Rp (_FnType) (_P0, ...);
2675};
2676
2677template <class _Rp, class _Class, class _P0, class _P1>
2678struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1) const volatile, true, false>
2679{
2680    typedef _Class const volatile _ClassType;
2681    typedef _Rp _ReturnType;
2682    typedef _Rp (_FnType) (_P0, _P1);
2683};
2684
2685template <class _Rp, class _Class, class _P0, class _P1>
2686struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, ...) const volatile, true, false>
2687{
2688    typedef _Class const volatile _ClassType;
2689    typedef _Rp _ReturnType;
2690    typedef _Rp (_FnType) (_P0, _P1, ...);
2691};
2692
2693template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2694struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2) const volatile, true, false>
2695{
2696    typedef _Class const volatile _ClassType;
2697    typedef _Rp _ReturnType;
2698    typedef _Rp (_FnType) (_P0, _P1, _P2);
2699};
2700
2701template <class _Rp, class _Class, class _P0, class _P1, class _P2>
2702struct __member_pointer_traits_imp<_Rp (_Class::*)(_P0, _P1, _P2, ...) const volatile, true, false>
2703{
2704    typedef _Class const volatile _ClassType;
2705    typedef _Rp _ReturnType;
2706    typedef _Rp (_FnType) (_P0, _P1, _P2, ...);
2707};
2708
2709#endif  // _LIBCPP_HAS_NO_VARIADICS
2710
2711template <class _Rp, class _Class>
2712struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2713{
2714    typedef _Class _ClassType;
2715    typedef _Rp _ReturnType;
2716};
2717
2718template <class _MP>
2719struct __member_pointer_traits
2720    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2721                    is_member_function_pointer<_MP>::value,
2722                    is_member_object_pointer<_MP>::value>
2723{
2724//     typedef ... _ClassType;
2725//     typedef ... _ReturnType;
2726//     typedef ... _FnType;
2727};
2728
2729
2730template <class _DecayedFp>
2731struct __member_pointer_class_type {};
2732
2733template <class _Ret, class _ClassType>
2734struct __member_pointer_class_type<_Ret _ClassType::*> {
2735  typedef _ClassType type;
2736};
2737
2738// result_of
2739
2740template <class _Callable> class result_of;
2741
2742#ifdef _LIBCPP_HAS_NO_VARIADICS
2743
2744template <class _Fn, bool, bool>
2745class __result_of
2746{
2747};
2748
2749template <class _Fn>
2750class __result_of<_Fn(), true, false>
2751{
2752public:
2753    typedef decltype(declval<_Fn>()()) type;
2754};
2755
2756template <class _Fn, class _A0>
2757class __result_of<_Fn(_A0), true, false>
2758{
2759public:
2760    typedef decltype(declval<_Fn>()(declval<_A0>())) type;
2761};
2762
2763template <class _Fn, class _A0, class _A1>
2764class __result_of<_Fn(_A0, _A1), true, false>
2765{
2766public:
2767    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>())) type;
2768};
2769
2770template <class _Fn, class _A0, class _A1, class _A2>
2771class __result_of<_Fn(_A0, _A1, _A2), true, false>
2772{
2773public:
2774    typedef decltype(declval<_Fn>()(declval<_A0>(), declval<_A1>(), declval<_A2>())) type;
2775};
2776
2777template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
2778struct __result_of_mp;
2779
2780// member function pointer
2781
2782template <class _MP, class _Tp>
2783struct __result_of_mp<_MP, _Tp, true>
2784    : public __identity<typename __member_pointer_traits<_MP>::_ReturnType>
2785{
2786};
2787
2788// member data pointer
2789
2790template <class _MP, class _Tp, bool>
2791struct __result_of_mdp;
2792
2793template <class _Rp, class _Class, class _Tp>
2794struct __result_of_mdp<_Rp _Class::*, _Tp, false>
2795{
2796    typedef typename __apply_cv<decltype(*_VSTD::declval<_Tp>()), _Rp>::type& type;
2797};
2798
2799template <class _Rp, class _Class, class _Tp>
2800struct __result_of_mdp<_Rp _Class::*, _Tp, true>
2801{
2802    typedef typename __apply_cv<_Tp, _Rp>::type& type;
2803};
2804
2805template <class _Rp, class _Class, class _Tp>
2806struct __result_of_mp<_Rp _Class::*, _Tp, false>
2807    : public __result_of_mdp<_Rp _Class::*, _Tp,
2808            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
2809{
2810};
2811
2812
2813
2814template <class _Fn, class _Tp>
2815class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
2816    : public __result_of_mp<typename remove_reference<_Fn>::type,
2817                            _Tp,
2818                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2819{
2820};
2821
2822template <class _Fn, class _Tp, class _A0>
2823class __result_of<_Fn(_Tp, _A0), false, true>  // _Fn must be member pointer
2824    : public __result_of_mp<typename remove_reference<_Fn>::type,
2825                            _Tp,
2826                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2827{
2828};
2829
2830template <class _Fn, class _Tp, class _A0, class _A1>
2831class __result_of<_Fn(_Tp, _A0, _A1), false, true>  // _Fn must be member pointer
2832    : public __result_of_mp<typename remove_reference<_Fn>::type,
2833                            _Tp,
2834                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2835{
2836};
2837
2838template <class _Fn, class _Tp, class _A0, class _A1, class _A2>
2839class __result_of<_Fn(_Tp, _A0, _A1, _A2), false, true>  // _Fn must be member pointer
2840    : public __result_of_mp<typename remove_reference<_Fn>::type,
2841                            _Tp,
2842                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
2843{
2844};
2845
2846// result_of
2847
2848template <class _Fn>
2849class _LIBCPP_TYPE_VIS_ONLY result_of<_Fn()>
2850    : public __result_of<_Fn(),
2851                         is_class<typename remove_reference<_Fn>::type>::value ||
2852                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2853                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2854                        >
2855{
2856};
2857
2858template <class _Fn, class _A0>
2859class _LIBCPP_TYPE_VIS_ONLY result_of<_Fn(_A0)>
2860    : public __result_of<_Fn(_A0),
2861                         is_class<typename remove_reference<_Fn>::type>::value ||
2862                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2863                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2864                        >
2865{
2866};
2867
2868template <class _Fn, class _A0, class _A1>
2869class _LIBCPP_TYPE_VIS_ONLY result_of<_Fn(_A0, _A1)>
2870    : public __result_of<_Fn(_A0, _A1),
2871                         is_class<typename remove_reference<_Fn>::type>::value ||
2872                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2873                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2874                        >
2875{
2876};
2877
2878template <class _Fn, class _A0, class _A1, class _A2>
2879class _LIBCPP_TYPE_VIS_ONLY result_of<_Fn(_A0, _A1, _A2)>
2880    : public __result_of<_Fn(_A0, _A1, _A2),
2881                         is_class<typename remove_reference<_Fn>::type>::value ||
2882                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
2883                         is_member_pointer<typename remove_reference<_Fn>::type>::value
2884                        >
2885{
2886};
2887
2888#endif  // _LIBCPP_HAS_NO_VARIADICS
2889
2890// template <class T, class... Args> struct is_constructible;
2891
2892namespace __is_construct
2893{
2894struct __nat {};
2895}
2896
2897#if __has_feature(is_constructible)
2898
2899template <class _Tp, class ..._Args>
2900struct _LIBCPP_TYPE_VIS_ONLY is_constructible
2901    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
2902    {};
2903
2904#else
2905
2906#ifndef _LIBCPP_HAS_NO_VARIADICS
2907
2908//      main is_constructible test
2909
2910
2911struct __is_constructible_helper
2912{
2913    template <class _Tp>
2914    static true_type __test_ref(_Tp);
2915    template <class>
2916    static false_type __test_ref(...);
2917
2918    template <class _Tp, class ..._Args,
2919        class = decltype(_Tp(_VSTD::declval<_Args>()...))>
2920    static true_type __test_nary(int);
2921    template <class _Tp, class...>
2922    static false_type __test_nary(...);
2923
2924    template <class _Tp, class _A0, class = decltype(::new _Tp(_VSTD::declval<_A0>()))>
2925    static is_destructible<_Tp> __test_unary(int);
2926    template <class, class>
2927    static false_type __test_unary(...);
2928};
2929
2930template <class _Tp, bool = is_void<_Tp>::value>
2931struct __is_default_constructible
2932    : decltype(__is_constructible_helper::__test_nary<_Tp>(0))
2933{};
2934
2935template <class _Tp>
2936struct __is_default_constructible<_Tp, true> : false_type {};
2937
2938template <class _Tp>
2939struct __is_default_constructible<_Tp[], false> : false_type {};
2940
2941template <class _Tp, size_t _Nx>
2942struct __is_default_constructible<_Tp[_Nx], false>
2943    : __is_default_constructible<typename remove_all_extents<_Tp>::type>  {};
2944
2945template <class _Tp, class... _Args>
2946struct __libcpp_is_constructible
2947{
2948  static_assert(sizeof...(_Args) > 1, "Wrong specialization");
2949  typedef decltype(__is_constructible_helper::__test_nary<_Tp, _Args...>(0))
2950      type;
2951};
2952
2953template <class _Tp>
2954struct __libcpp_is_constructible<_Tp> : __is_default_constructible<_Tp> {};
2955
2956template <class _Tp, class _A0>
2957struct __libcpp_is_constructible<_Tp, _A0>
2958    : public decltype(__is_constructible_helper::__test_unary<_Tp, _A0>(0))
2959{};
2960
2961template <class _Tp, class _A0>
2962struct __libcpp_is_constructible<_Tp&, _A0>
2963    : public decltype(__is_constructible_helper::
2964    __test_ref<_Tp&>(_VSTD::declval<_A0>()))
2965{};
2966
2967template <class _Tp, class _A0>
2968struct __libcpp_is_constructible<_Tp&&, _A0>
2969    : public decltype(__is_constructible_helper::
2970    __test_ref<_Tp&&>(_VSTD::declval<_A0>()))
2971{};
2972
2973//      is_constructible entry point
2974
2975template <class _Tp, class... _Args>
2976struct _LIBCPP_TYPE_VIS_ONLY is_constructible
2977    : public __libcpp_is_constructible<_Tp, _Args...>::type {};
2978
2979
2980#else  // _LIBCPP_HAS_NO_VARIADICS
2981
2982// template <class T> struct is_constructible0;
2983
2984//      main is_constructible0 test
2985
2986template <class _Tp>
2987decltype((_Tp(), true_type()))
2988__is_constructible0_test(_Tp&);
2989
2990false_type
2991__is_constructible0_test(__any);
2992
2993template <class _Tp, class _A0>
2994decltype((_Tp(_VSTD::declval<_A0>()), true_type()))
2995__is_constructible1_test(_Tp&, _A0&);
2996
2997template <class _A0>
2998false_type
2999__is_constructible1_test(__any, _A0&);
3000
3001template <class _Tp, class _A0, class _A1>
3002decltype((_Tp(_VSTD::declval<_A0>(), _VSTD::declval<_A1>()), true_type()))
3003__is_constructible2_test(_Tp&, _A0&, _A1&);
3004
3005template <class _A0, class _A1>
3006false_type
3007__is_constructible2_test(__any, _A0&, _A1&);
3008
3009template <bool, class _Tp>
3010struct __is_constructible0_imp // false, _Tp is not a scalar
3011    : public common_type
3012             <
3013                 decltype(__is_constructible0_test(declval<_Tp&>()))
3014             >::type
3015    {};
3016
3017template <bool, class _Tp, class _A0>
3018struct __is_constructible1_imp // false, _Tp is not a scalar
3019    : public common_type
3020             <
3021                 decltype(__is_constructible1_test(declval<_Tp&>(), declval<_A0&>()))
3022             >::type
3023    {};
3024
3025template <bool, class _Tp, class _A0, class _A1>
3026struct __is_constructible2_imp // false, _Tp is not a scalar
3027    : public common_type
3028             <
3029                 decltype(__is_constructible2_test(declval<_Tp&>(), declval<_A0>(), declval<_A1>()))
3030             >::type
3031    {};
3032
3033//      handle scalars and reference types
3034
3035//      Scalars are default constructible, references are not
3036
3037template <class _Tp>
3038struct __is_constructible0_imp<true, _Tp>
3039    : public is_scalar<_Tp>
3040    {};
3041
3042template <class _Tp, class _A0>
3043struct __is_constructible1_imp<true, _Tp, _A0>
3044    : public is_convertible<_A0, _Tp>
3045    {};
3046
3047template <class _Tp, class _A0, class _A1>
3048struct __is_constructible2_imp<true, _Tp, _A0, _A1>
3049    : public false_type
3050    {};
3051
3052//      Treat scalars and reference types separately
3053
3054template <bool, class _Tp>
3055struct __is_constructible0_void_check
3056    : public __is_constructible0_imp<is_scalar<_Tp>::value || is_reference<_Tp>::value,
3057                                _Tp>
3058    {};
3059
3060template <bool, class _Tp, class _A0>
3061struct __is_constructible1_void_check
3062    : public __is_constructible1_imp<is_scalar<_Tp>::value || is_reference<_Tp>::value,
3063                                _Tp, _A0>
3064    {};
3065
3066template <bool, class _Tp, class _A0, class _A1>
3067struct __is_constructible2_void_check
3068    : public __is_constructible2_imp<is_scalar<_Tp>::value || is_reference<_Tp>::value,
3069                                _Tp, _A0, _A1>
3070    {};
3071
3072//      If any of T or Args is void, is_constructible should be false
3073
3074template <class _Tp>
3075struct __is_constructible0_void_check<true, _Tp>
3076    : public false_type
3077    {};
3078
3079template <class _Tp, class _A0>
3080struct __is_constructible1_void_check<true, _Tp, _A0>
3081    : public false_type
3082    {};
3083
3084template <class _Tp, class _A0, class _A1>
3085struct __is_constructible2_void_check<true, _Tp, _A0, _A1>
3086    : public false_type
3087    {};
3088
3089//      is_constructible entry point
3090
3091template <class _Tp, class _A0 = __is_construct::__nat,
3092                     class _A1 = __is_construct::__nat>
3093struct _LIBCPP_TYPE_VIS_ONLY is_constructible
3094    : public __is_constructible2_void_check<is_void<_Tp>::value
3095                                        || is_abstract<_Tp>::value
3096                                        || is_function<_Tp>::value
3097                                        || is_void<_A0>::value
3098                                        || is_void<_A1>::value,
3099                                           _Tp, _A0, _A1>
3100    {};
3101
3102template <class _Tp>
3103struct _LIBCPP_TYPE_VIS_ONLY is_constructible<_Tp, __is_construct::__nat, __is_construct::__nat>
3104    : public __is_constructible0_void_check<is_void<_Tp>::value
3105                                        || is_abstract<_Tp>::value
3106                                        || is_function<_Tp>::value,
3107                                           _Tp>
3108    {};
3109
3110template <class _Tp, class _A0>
3111struct _LIBCPP_TYPE_VIS_ONLY is_constructible<_Tp, _A0, __is_construct::__nat>
3112    : public __is_constructible1_void_check<is_void<_Tp>::value
3113                                        || is_abstract<_Tp>::value
3114                                        || is_function<_Tp>::value
3115                                        || is_void<_A0>::value,
3116                                           _Tp, _A0>
3117    {};
3118
3119//      Array types are default constructible if their element type
3120//      is default constructible
3121
3122template <class _Ap, size_t _Np>
3123struct __is_constructible0_imp<false, _Ap[_Np]>
3124    : public is_constructible<typename remove_all_extents<_Ap>::type>
3125    {};
3126
3127template <class _Ap, size_t _Np, class _A0>
3128struct __is_constructible1_imp<false, _Ap[_Np], _A0>
3129    : public false_type
3130    {};
3131
3132template <class _Ap, size_t _Np, class _A0, class _A1>
3133struct __is_constructible2_imp<false, _Ap[_Np], _A0, _A1>
3134    : public false_type
3135    {};
3136
3137//      Incomplete array types are not constructible
3138
3139template <class _Ap>
3140struct __is_constructible0_imp<false, _Ap[]>
3141    : public false_type
3142    {};
3143
3144template <class _Ap, class _A0>
3145struct __is_constructible1_imp<false, _Ap[], _A0>
3146    : public false_type
3147    {};
3148
3149template <class _Ap, class _A0, class _A1>
3150struct __is_constructible2_imp<false, _Ap[], _A0, _A1>
3151    : public false_type
3152    {};
3153
3154#endif  // _LIBCPP_HAS_NO_VARIADICS
3155#endif  // __has_feature(is_constructible)
3156
3157#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
3158template <class _Tp, class ..._Args> _LIBCPP_CONSTEXPR bool is_constructible_v
3159    = is_constructible<_Tp, _Args...>::value;
3160#endif
3161
3162// is_default_constructible
3163
3164template <class _Tp>
3165struct _LIBCPP_TYPE_VIS_ONLY is_default_constructible
3166    : public is_constructible<_Tp>
3167    {};
3168
3169#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3170template <class _Tp> _LIBCPP_CONSTEXPR bool is_default_constructible_v
3171    = is_default_constructible<_Tp>::value;
3172#endif
3173
3174// is_copy_constructible
3175
3176template <class _Tp>
3177struct _LIBCPP_TYPE_VIS_ONLY is_copy_constructible
3178    : public is_constructible<_Tp,
3179                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3180
3181#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3182template <class _Tp> _LIBCPP_CONSTEXPR bool is_copy_constructible_v
3183    = is_copy_constructible<_Tp>::value;
3184#endif
3185
3186// is_move_constructible
3187
3188template <class _Tp>
3189struct _LIBCPP_TYPE_VIS_ONLY is_move_constructible
3190#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3191    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3192#else
3193    : public is_copy_constructible<_Tp>
3194#endif
3195    {};
3196
3197#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3198template <class _Tp> _LIBCPP_CONSTEXPR bool is_move_constructible_v
3199    = is_move_constructible<_Tp>::value;
3200#endif
3201
3202// is_trivially_constructible
3203
3204#ifndef _LIBCPP_HAS_NO_VARIADICS
3205
3206#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3207
3208template <class _Tp, class... _Args>
3209struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible
3210    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3211{
3212};
3213
3214#else  // !__has_feature(is_trivially_constructible)
3215
3216template <class _Tp, class... _Args>
3217struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible
3218    : false_type
3219{
3220};
3221
3222template <class _Tp>
3223struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp>
3224#if __has_feature(has_trivial_constructor) || (_GNUC_VER >= 403)
3225    : integral_constant<bool, __has_trivial_constructor(_Tp)>
3226#else
3227    : integral_constant<bool, is_scalar<_Tp>::value>
3228#endif
3229{
3230};
3231
3232template <class _Tp>
3233#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3234struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp&&>
3235#else
3236struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp>
3237#endif
3238    : integral_constant<bool, is_scalar<_Tp>::value>
3239{
3240};
3241
3242template <class _Tp>
3243struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, const _Tp&>
3244    : integral_constant<bool, is_scalar<_Tp>::value>
3245{
3246};
3247
3248template <class _Tp>
3249struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp&>
3250    : integral_constant<bool, is_scalar<_Tp>::value>
3251{
3252};
3253
3254#endif  // !__has_feature(is_trivially_constructible)
3255
3256#else  // _LIBCPP_HAS_NO_VARIADICS
3257
3258template <class _Tp, class _A0 = __is_construct::__nat,
3259                     class _A1 = __is_construct::__nat>
3260struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible
3261    : false_type
3262{
3263};
3264
3265#if __has_feature(is_trivially_constructible) || _GNUC_VER >= 501
3266
3267template <class _Tp>
3268struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, __is_construct::__nat,
3269                                                       __is_construct::__nat>
3270    : integral_constant<bool, __is_trivially_constructible(_Tp)>
3271{
3272};
3273
3274template <class _Tp>
3275struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp,
3276                                                       __is_construct::__nat>
3277    : integral_constant<bool, __is_trivially_constructible(_Tp, _Tp)>
3278{
3279};
3280
3281template <class _Tp>
3282struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, const _Tp&,
3283                                                       __is_construct::__nat>
3284    : integral_constant<bool, __is_trivially_constructible(_Tp, const _Tp&)>
3285{
3286};
3287
3288template <class _Tp>
3289struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp&,
3290                                                       __is_construct::__nat>
3291    : integral_constant<bool, __is_trivially_constructible(_Tp, _Tp&)>
3292{
3293};
3294
3295#else  // !__has_feature(is_trivially_constructible)
3296
3297template <class _Tp>
3298struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, __is_construct::__nat,
3299                                                       __is_construct::__nat>
3300    : integral_constant<bool, is_scalar<_Tp>::value>
3301{
3302};
3303
3304template <class _Tp>
3305struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp,
3306                                                       __is_construct::__nat>
3307    : integral_constant<bool, is_scalar<_Tp>::value>
3308{
3309};
3310
3311template <class _Tp>
3312struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, const _Tp&,
3313                                                       __is_construct::__nat>
3314    : integral_constant<bool, is_scalar<_Tp>::value>
3315{
3316};
3317
3318template <class _Tp>
3319struct _LIBCPP_TYPE_VIS_ONLY is_trivially_constructible<_Tp, _Tp&,
3320                                                       __is_construct::__nat>
3321    : integral_constant<bool, is_scalar<_Tp>::value>
3322{
3323};
3324
3325#endif  // !__has_feature(is_trivially_constructible)
3326
3327#endif  // _LIBCPP_HAS_NO_VARIADICS
3328
3329#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
3330template <class _Tp, class... _Args> _LIBCPP_CONSTEXPR bool is_trivially_constructible_v
3331    = is_trivially_constructible<_Tp, _Args...>::value;
3332#endif
3333
3334// is_trivially_default_constructible
3335
3336template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_default_constructible
3337    : public is_trivially_constructible<_Tp>
3338    {};
3339
3340#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3341template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_default_constructible_v
3342    = is_trivially_default_constructible<_Tp>::value;
3343#endif
3344
3345// is_trivially_copy_constructible
3346
3347template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_copy_constructible
3348    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3349    {};
3350
3351#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3352template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_copy_constructible_v
3353    = is_trivially_copy_constructible<_Tp>::value;
3354#endif
3355
3356// is_trivially_move_constructible
3357
3358template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_move_constructible
3359#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3360    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3361#else
3362    : public is_trivially_copy_constructible<_Tp>
3363#endif
3364    {};
3365
3366#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3367template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_move_constructible_v
3368    = is_trivially_move_constructible<_Tp>::value;
3369#endif
3370
3371// is_trivially_assignable
3372
3373#if __has_feature(is_trivially_assignable) || _GNUC_VER >= 501
3374
3375template <class _Tp, class _Arg>
3376struct is_trivially_assignable
3377    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3378{
3379};
3380
3381#else  // !__has_feature(is_trivially_assignable)
3382
3383template <class _Tp, class _Arg>
3384struct is_trivially_assignable
3385    : public false_type {};
3386
3387template <class _Tp>
3388struct is_trivially_assignable<_Tp&, _Tp>
3389    : integral_constant<bool, is_scalar<_Tp>::value> {};
3390
3391template <class _Tp>
3392struct is_trivially_assignable<_Tp&, _Tp&>
3393    : integral_constant<bool, is_scalar<_Tp>::value> {};
3394
3395template <class _Tp>
3396struct is_trivially_assignable<_Tp&, const _Tp&>
3397    : integral_constant<bool, is_scalar<_Tp>::value> {};
3398
3399#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3400
3401template <class _Tp>
3402struct is_trivially_assignable<_Tp&, _Tp&&>
3403    : integral_constant<bool, is_scalar<_Tp>::value> {};
3404
3405#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
3406
3407#endif  // !__has_feature(is_trivially_assignable)
3408
3409#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3410template <class _Tp, class _Arg> _LIBCPP_CONSTEXPR bool is_trivially_assignable_v
3411    = is_trivially_assignable<_Tp, _Arg>::value;
3412#endif
3413
3414// is_trivially_copy_assignable
3415
3416template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_copy_assignable
3417    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3418                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3419
3420#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3421template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_copy_assignable_v
3422    = is_trivially_copy_assignable<_Tp>::value;
3423#endif
3424
3425// is_trivially_move_assignable
3426
3427template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_move_assignable
3428    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3429#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3430                                     typename add_rvalue_reference<_Tp>::type>
3431#else
3432                                     typename add_lvalue_reference<_Tp>::type>
3433#endif
3434    {};
3435
3436#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3437template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_move_assignable_v
3438    = is_trivially_move_assignable<_Tp>::value;
3439#endif
3440
3441// is_trivially_destructible
3442
3443#if __has_feature(has_trivial_destructor) || (_GNUC_VER >= 403)
3444
3445template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_destructible
3446    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3447
3448#else
3449
3450template <class _Tp> struct __libcpp_trivial_destructor
3451    : public integral_constant<bool, is_scalar<_Tp>::value ||
3452                                     is_reference<_Tp>::value> {};
3453
3454template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_destructible
3455    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3456
3457template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_destructible<_Tp[]>
3458    : public false_type {};
3459
3460#endif
3461
3462#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3463template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_destructible_v
3464    = is_trivially_destructible<_Tp>::value;
3465#endif
3466
3467// is_nothrow_constructible
3468
3469#if 0
3470template <class _Tp, class... _Args>
3471struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible
3472    : public integral_constant<bool, __is_nothrow_constructible(_Tp(_Args...))>
3473{
3474};
3475
3476#else
3477
3478#ifndef _LIBCPP_HAS_NO_VARIADICS
3479
3480#if __has_feature(cxx_noexcept) || (_GNUC_VER >= 407 && __cplusplus >= 201103L)
3481
3482template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3483
3484template <class _Tp, class... _Args>
3485struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3486    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3487{
3488};
3489
3490template <class _Tp>
3491void __implicit_conversion_to(_Tp) noexcept { }
3492
3493template <class _Tp, class _Arg>
3494struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3495    : public integral_constant<bool, noexcept(__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3496{
3497};
3498
3499template <class _Tp, bool _IsReference, class... _Args>
3500struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3501    : public false_type
3502{
3503};
3504
3505template <class _Tp, class... _Args>
3506struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible
3507    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3508{
3509};
3510
3511template <class _Tp, size_t _Ns>
3512struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp[_Ns]>
3513    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3514{
3515};
3516
3517#else  // __has_feature(cxx_noexcept)
3518
3519template <class _Tp, class... _Args>
3520struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible
3521    : false_type
3522{
3523};
3524
3525template <class _Tp>
3526struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp>
3527#if __has_feature(has_nothrow_constructor) || (_GNUC_VER >= 403)
3528    : integral_constant<bool, __has_nothrow_constructor(_Tp)>
3529#else
3530    : integral_constant<bool, is_scalar<_Tp>::value>
3531#endif
3532{
3533};
3534
3535template <class _Tp>
3536#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3537struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, _Tp&&>
3538#else
3539struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, _Tp>
3540#endif
3541#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3542    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3543#else
3544    : integral_constant<bool, is_scalar<_Tp>::value>
3545#endif
3546{
3547};
3548
3549template <class _Tp>
3550struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, const _Tp&>
3551#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3552    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3553#else
3554    : integral_constant<bool, is_scalar<_Tp>::value>
3555#endif
3556{
3557};
3558
3559template <class _Tp>
3560struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, _Tp&>
3561#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3562    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3563#else
3564    : integral_constant<bool, is_scalar<_Tp>::value>
3565#endif
3566{
3567};
3568
3569#endif  // __has_feature(cxx_noexcept)
3570
3571#else  // _LIBCPP_HAS_NO_VARIADICS
3572
3573template <class _Tp, class _A0 = __is_construct::__nat,
3574                     class _A1 = __is_construct::__nat>
3575struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible
3576    : false_type
3577{
3578};
3579
3580template <class _Tp>
3581struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, __is_construct::__nat,
3582                                                       __is_construct::__nat>
3583#if __has_feature(has_nothrow_constructor) || (_GNUC_VER >= 403)
3584    : integral_constant<bool, __has_nothrow_constructor(_Tp)>
3585#else
3586    : integral_constant<bool, is_scalar<_Tp>::value>
3587#endif
3588{
3589};
3590
3591template <class _Tp>
3592struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, _Tp,
3593                                                       __is_construct::__nat>
3594#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3595    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3596#else
3597    : integral_constant<bool, is_scalar<_Tp>::value>
3598#endif
3599{
3600};
3601
3602template <class _Tp>
3603struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, const _Tp&,
3604                                                       __is_construct::__nat>
3605#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3606    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3607#else
3608    : integral_constant<bool, is_scalar<_Tp>::value>
3609#endif
3610{
3611};
3612
3613template <class _Tp>
3614struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_constructible<_Tp, _Tp&,
3615                                                       __is_construct::__nat>
3616#if __has_feature(has_nothrow_copy) || (_GNUC_VER >= 403)
3617    : integral_constant<bool, __has_nothrow_copy(_Tp)>
3618#else
3619    : integral_constant<bool, is_scalar<_Tp>::value>
3620#endif
3621{
3622};
3623
3624#endif  // _LIBCPP_HAS_NO_VARIADICS
3625#endif  // __has_feature(is_nothrow_constructible)
3626
3627#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
3628template <class _Tp, class ..._Args> _LIBCPP_CONSTEXPR bool is_nothrow_constructible_v
3629    = is_nothrow_constructible<_Tp, _Args...>::value;
3630#endif
3631
3632// is_nothrow_default_constructible
3633
3634template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_default_constructible
3635    : public is_nothrow_constructible<_Tp>
3636    {};
3637
3638#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3639template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_default_constructible_v
3640    = is_nothrow_default_constructible<_Tp>::value;
3641#endif
3642
3643// is_nothrow_copy_constructible
3644
3645template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_copy_constructible
3646    : public is_nothrow_constructible<_Tp,
3647                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3648
3649#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3650template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_copy_constructible_v
3651    = is_nothrow_copy_constructible<_Tp>::value;
3652#endif
3653
3654// is_nothrow_move_constructible
3655
3656template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_move_constructible
3657#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3658    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3659#else
3660    : public is_nothrow_copy_constructible<_Tp>
3661#endif
3662    {};
3663
3664#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3665template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_move_constructible_v
3666    = is_nothrow_move_constructible<_Tp>::value;
3667#endif
3668
3669// is_nothrow_assignable
3670
3671#if __has_feature(cxx_noexcept) || (_GNUC_VER >= 407 && __cplusplus >= 201103L)
3672
3673template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3674
3675template <class _Tp, class _Arg>
3676struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3677    : public false_type
3678{
3679};
3680
3681template <class _Tp, class _Arg>
3682struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3683    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>()) >
3684{
3685};
3686
3687template <class _Tp, class _Arg>
3688struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_assignable
3689    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3690{
3691};
3692
3693#else  // __has_feature(cxx_noexcept)
3694
3695template <class _Tp, class _Arg>
3696struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_assignable
3697    : public false_type {};
3698
3699template <class _Tp>
3700struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_assignable<_Tp&, _Tp>
3701#if __has_feature(has_nothrow_assign) || (_GNUC_VER >= 403)
3702    : integral_constant<bool, __has_nothrow_assign(_Tp)> {};
3703#else
3704    : integral_constant<bool, is_scalar<_Tp>::value> {};
3705#endif
3706
3707template <class _Tp>
3708struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_assignable<_Tp&, _Tp&>
3709#if __has_feature(has_nothrow_assign) || (_GNUC_VER >= 403)
3710    : integral_constant<bool, __has_nothrow_assign(_Tp)> {};
3711#else
3712    : integral_constant<bool, is_scalar<_Tp>::value> {};
3713#endif
3714
3715template <class _Tp>
3716struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_assignable<_Tp&, const _Tp&>
3717#if __has_feature(has_nothrow_assign) || (_GNUC_VER >= 403)
3718    : integral_constant<bool, __has_nothrow_assign(_Tp)> {};
3719#else
3720    : integral_constant<bool, is_scalar<_Tp>::value> {};
3721#endif
3722
3723#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3724
3725template <class _Tp>
3726struct is_nothrow_assignable<_Tp&, _Tp&&>
3727#if __has_feature(has_nothrow_assign) || (_GNUC_VER >= 403)
3728    : integral_constant<bool, __has_nothrow_assign(_Tp)> {};
3729#else
3730    : integral_constant<bool, is_scalar<_Tp>::value> {};
3731#endif
3732
3733#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
3734
3735#endif  // __has_feature(cxx_noexcept)
3736
3737#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3738template <class _Tp, class _Arg> _LIBCPP_CONSTEXPR bool is_nothrow_assignable_v
3739    = is_nothrow_assignable<_Tp, _Arg>::value;
3740#endif
3741
3742// is_nothrow_copy_assignable
3743
3744template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_copy_assignable
3745    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3746                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3747
3748#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3749template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_copy_assignable_v
3750    = is_nothrow_copy_assignable<_Tp>::value;
3751#endif
3752
3753// is_nothrow_move_assignable
3754
3755template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_move_assignable
3756    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3757#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3758                                     typename add_rvalue_reference<_Tp>::type>
3759#else
3760                                     typename add_lvalue_reference<_Tp>::type>
3761#endif
3762    {};
3763
3764#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3765template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_move_assignable_v
3766    = is_nothrow_move_assignable<_Tp>::value;
3767#endif
3768
3769// is_nothrow_destructible
3770
3771#if __has_feature(cxx_noexcept) || (_GNUC_VER >= 407 && __cplusplus >= 201103L)
3772
3773template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3774
3775template <class _Tp>
3776struct __libcpp_is_nothrow_destructible<false, _Tp>
3777    : public false_type
3778{
3779};
3780
3781template <class _Tp>
3782struct __libcpp_is_nothrow_destructible<true, _Tp>
3783    : public integral_constant<bool, noexcept(_VSTD::declval<_Tp>().~_Tp()) >
3784{
3785};
3786
3787template <class _Tp>
3788struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible
3789    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3790{
3791};
3792
3793template <class _Tp, size_t _Ns>
3794struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible<_Tp[_Ns]>
3795    : public is_nothrow_destructible<_Tp>
3796{
3797};
3798
3799template <class _Tp>
3800struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible<_Tp&>
3801    : public true_type
3802{
3803};
3804
3805#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3806
3807template <class _Tp>
3808struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible<_Tp&&>
3809    : public true_type
3810{
3811};
3812
3813#endif
3814
3815#else
3816
3817template <class _Tp> struct __libcpp_nothrow_destructor
3818    : public integral_constant<bool, is_scalar<_Tp>::value ||
3819                                     is_reference<_Tp>::value> {};
3820
3821template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible
3822    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3823
3824template <class _Tp>
3825struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_destructible<_Tp[]>
3826    : public false_type {};
3827
3828#endif
3829
3830#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3831template <class _Tp> _LIBCPP_CONSTEXPR bool is_nothrow_destructible_v
3832    = is_nothrow_destructible<_Tp>::value;
3833#endif
3834
3835// is_pod
3836
3837#if __has_feature(is_pod) || (_GNUC_VER >= 403)
3838
3839template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_pod
3840    : public integral_constant<bool, __is_pod(_Tp)> {};
3841
3842#else
3843
3844template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_pod
3845    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3846                                     is_trivially_copy_constructible<_Tp>::value      &&
3847                                     is_trivially_copy_assignable<_Tp>::value    &&
3848                                     is_trivially_destructible<_Tp>::value> {};
3849
3850#endif
3851
3852#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3853template <class _Tp> _LIBCPP_CONSTEXPR bool is_pod_v
3854    = is_pod<_Tp>::value;
3855#endif
3856
3857// is_literal_type;
3858
3859template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_literal_type
3860#ifdef _LIBCPP_IS_LITERAL
3861    : public integral_constant<bool, _LIBCPP_IS_LITERAL(_Tp)>
3862#else
3863    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value ||
3864                              is_reference<typename remove_all_extents<_Tp>::type>::value>
3865#endif
3866    {};
3867
3868#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3869template <class _Tp> _LIBCPP_CONSTEXPR bool is_literal_type_v
3870    = is_literal_type<_Tp>::value;
3871#endif
3872
3873// is_standard_layout;
3874
3875template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_standard_layout
3876#if __has_feature(is_standard_layout) || (_GNUC_VER >= 407)
3877    : public integral_constant<bool, __is_standard_layout(_Tp)>
3878#else
3879    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3880#endif
3881    {};
3882
3883#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3884template <class _Tp> _LIBCPP_CONSTEXPR bool is_standard_layout_v
3885    = is_standard_layout<_Tp>::value;
3886#endif
3887
3888// is_trivially_copyable;
3889
3890template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivially_copyable
3891#if __has_feature(is_trivially_copyable)
3892    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3893#elif _GNUC_VER >= 501
3894    : public integral_constant<bool, !is_volatile<_Tp>::value && __is_trivially_copyable(_Tp)>
3895#else
3896    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3897#endif
3898    {};
3899
3900#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3901template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivially_copyable_v
3902    = is_trivially_copyable<_Tp>::value;
3903#endif
3904
3905// is_trivial;
3906
3907template <class _Tp> struct _LIBCPP_TYPE_VIS_ONLY is_trivial
3908#if __has_feature(is_trivial) || _GNUC_VER >= 407
3909    : public integral_constant<bool, __is_trivial(_Tp)>
3910#else
3911    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3912                                 is_trivially_default_constructible<_Tp>::value>
3913#endif
3914    {};
3915
3916#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
3917template <class _Tp> _LIBCPP_CONSTEXPR bool is_trivial_v
3918    = is_trivial<_Tp>::value;
3919#endif
3920
3921template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3922template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3923template <class _Tp> struct __is_reference_wrapper
3924    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3925
3926#ifndef _LIBCPP_CXX03_LANG
3927
3928// Check for complete types
3929
3930template <class ..._Tp> struct __check_complete;
3931
3932template <>
3933struct __check_complete<>
3934{
3935};
3936
3937template <class _Hp, class _T0, class ..._Tp>
3938struct __check_complete<_Hp, _T0, _Tp...>
3939    : private __check_complete<_Hp>,
3940      private __check_complete<_T0, _Tp...>
3941{
3942};
3943
3944template <class _Hp>
3945struct __check_complete<_Hp, _Hp>
3946    : private __check_complete<_Hp>
3947{
3948};
3949
3950template <class _Tp>
3951struct __check_complete<_Tp>
3952{
3953    static_assert(sizeof(_Tp) > 0, "Type must be complete.");
3954};
3955
3956template <class _Tp>
3957struct __check_complete<_Tp&>
3958    : private __check_complete<_Tp>
3959{
3960};
3961
3962template <class _Tp>
3963struct __check_complete<_Tp&&>
3964    : private __check_complete<_Tp>
3965{
3966};
3967
3968template <class _Rp, class ..._Param>
3969struct __check_complete<_Rp (*)(_Param...)>
3970    : private __check_complete<_Rp>
3971{
3972};
3973
3974template <class ..._Param>
3975struct __check_complete<void (*)(_Param...)>
3976{
3977};
3978
3979template <class _Rp, class ..._Param>
3980struct __check_complete<_Rp (_Param...)>
3981    : private __check_complete<_Rp>
3982{
3983};
3984
3985template <class ..._Param>
3986struct __check_complete<void (_Param...)>
3987{
3988};
3989
3990template <class _Rp, class _Class, class ..._Param>
3991struct __check_complete<_Rp (_Class::*)(_Param...)>
3992    : private __check_complete<_Class>
3993{
3994};
3995
3996template <class _Rp, class _Class, class ..._Param>
3997struct __check_complete<_Rp (_Class::*)(_Param...) const>
3998    : private __check_complete<_Class>
3999{
4000};
4001
4002template <class _Rp, class _Class, class ..._Param>
4003struct __check_complete<_Rp (_Class::*)(_Param...) volatile>
4004    : private __check_complete<_Class>
4005{
4006};
4007
4008template <class _Rp, class _Class, class ..._Param>
4009struct __check_complete<_Rp (_Class::*)(_Param...) const volatile>
4010    : private __check_complete<_Class>
4011{
4012};
4013
4014template <class _Rp, class _Class, class ..._Param>
4015struct __check_complete<_Rp (_Class::*)(_Param...) &>
4016    : private __check_complete<_Class>
4017{
4018};
4019
4020template <class _Rp, class _Class, class ..._Param>
4021struct __check_complete<_Rp (_Class::*)(_Param...) const&>
4022    : private __check_complete<_Class>
4023{
4024};
4025
4026template <class _Rp, class _Class, class ..._Param>
4027struct __check_complete<_Rp (_Class::*)(_Param...) volatile&>
4028    : private __check_complete<_Class>
4029{
4030};
4031
4032template <class _Rp, class _Class, class ..._Param>
4033struct __check_complete<_Rp (_Class::*)(_Param...) const volatile&>
4034    : private __check_complete<_Class>
4035{
4036};
4037
4038template <class _Rp, class _Class, class ..._Param>
4039struct __check_complete<_Rp (_Class::*)(_Param...) &&>
4040    : private __check_complete<_Class>
4041{
4042};
4043
4044template <class _Rp, class _Class, class ..._Param>
4045struct __check_complete<_Rp (_Class::*)(_Param...) const&&>
4046    : private __check_complete<_Class>
4047{
4048};
4049
4050template <class _Rp, class _Class, class ..._Param>
4051struct __check_complete<_Rp (_Class::*)(_Param...) volatile&&>
4052    : private __check_complete<_Class>
4053{
4054};
4055
4056template <class _Rp, class _Class, class ..._Param>
4057struct __check_complete<_Rp (_Class::*)(_Param...) const volatile&&>
4058    : private __check_complete<_Class>
4059{
4060};
4061
4062template <class _Rp, class _Class>
4063struct __check_complete<_Rp _Class::*>
4064    : private __check_complete<_Class>
4065{
4066};
4067
4068
4069template <class _Fp, class _A0,
4070         class _DecayFp = typename decay<_Fp>::type,
4071         class _DecayA0 = typename decay<_A0>::type,
4072         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
4073using __enable_if_bullet1 = typename enable_if
4074    <
4075        is_member_function_pointer<_DecayFp>::value
4076        && is_base_of<_ClassT, _DecayA0>::value
4077    >::type;
4078
4079template <class _Fp, class _A0,
4080         class _DecayFp = typename decay<_Fp>::type,
4081         class _DecayA0 = typename decay<_A0>::type>
4082using __enable_if_bullet2 = typename enable_if
4083    <
4084        is_member_function_pointer<_DecayFp>::value
4085        && __is_reference_wrapper<_DecayA0>::value
4086    >::type;
4087
4088template <class _Fp, class _A0,
4089         class _DecayFp = typename decay<_Fp>::type,
4090         class _DecayA0 = typename decay<_A0>::type,
4091         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
4092using __enable_if_bullet3 = typename enable_if
4093    <
4094        is_member_function_pointer<_DecayFp>::value
4095        && !is_base_of<_ClassT, _DecayA0>::value
4096        && !__is_reference_wrapper<_DecayA0>::value
4097    >::type;
4098
4099template <class _Fp, class _A0,
4100         class _DecayFp = typename decay<_Fp>::type,
4101         class _DecayA0 = typename decay<_A0>::type,
4102         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
4103using __enable_if_bullet4 = typename enable_if
4104    <
4105        is_member_object_pointer<_DecayFp>::value
4106        && is_base_of<_ClassT, _DecayA0>::value
4107    >::type;
4108
4109template <class _Fp, class _A0,
4110         class _DecayFp = typename decay<_Fp>::type,
4111         class _DecayA0 = typename decay<_A0>::type>
4112using __enable_if_bullet5 = typename enable_if
4113    <
4114        is_member_object_pointer<_DecayFp>::value
4115        && __is_reference_wrapper<_DecayA0>::value
4116    >::type;
4117
4118template <class _Fp, class _A0,
4119         class _DecayFp = typename decay<_Fp>::type,
4120         class _DecayA0 = typename decay<_A0>::type,
4121         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
4122using __enable_if_bullet6 = typename enable_if
4123    <
4124        is_member_object_pointer<_DecayFp>::value
4125        && !is_base_of<_ClassT, _DecayA0>::value
4126        && !__is_reference_wrapper<_DecayA0>::value
4127    >::type;
4128
4129// __invoke forward declarations
4130
4131// fall back - none of the bullets
4132
4133#define _LIBCPP_INVOKE_RETURN(...) \
4134    noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) \
4135    { return __VA_ARGS__; }
4136
4137template <class ..._Args>
4138auto __invoke(__any, _Args&& ...__args) -> __nat;
4139
4140template <class ..._Args>
4141auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
4142
4143// bullets 1, 2 and 3
4144
4145template <class _Fp, class _A0, class ..._Args,
4146          class = __enable_if_bullet1<_Fp, _A0>>
4147inline _LIBCPP_INLINE_VISIBILITY
4148auto
4149__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4150_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
4151
4152template <class _Fp, class _A0, class ..._Args,
4153          class = __enable_if_bullet1<_Fp, _A0>>
4154inline _LIBCPP_INLINE_VISIBILITY
4155_LIBCPP_CONSTEXPR auto
4156__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4157_LIBCPP_INVOKE_RETURN((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
4158
4159template <class _Fp, class _A0, class ..._Args,
4160          class = __enable_if_bullet2<_Fp, _A0>>
4161inline _LIBCPP_INLINE_VISIBILITY
4162auto
4163__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4164_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
4165
4166template <class _Fp, class _A0, class ..._Args,
4167          class = __enable_if_bullet2<_Fp, _A0>>
4168inline _LIBCPP_INLINE_VISIBILITY
4169_LIBCPP_CONSTEXPR auto
4170__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4171_LIBCPP_INVOKE_RETURN((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
4172
4173template <class _Fp, class _A0, class ..._Args,
4174          class = __enable_if_bullet3<_Fp, _A0>>
4175inline _LIBCPP_INLINE_VISIBILITY
4176auto
4177__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4178_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
4179
4180template <class _Fp, class _A0, class ..._Args,
4181          class = __enable_if_bullet3<_Fp, _A0>>
4182inline _LIBCPP_INLINE_VISIBILITY
4183_LIBCPP_CONSTEXPR auto
4184__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
4185_LIBCPP_INVOKE_RETURN(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
4186
4187// bullets 4, 5 and 6
4188
4189template <class _Fp, class _A0,
4190          class = __enable_if_bullet4<_Fp, _A0>>
4191inline _LIBCPP_INLINE_VISIBILITY
4192auto
4193__invoke(_Fp&& __f, _A0&& __a0)
4194_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
4195
4196template <class _Fp, class _A0,
4197          class = __enable_if_bullet4<_Fp, _A0>>
4198inline _LIBCPP_INLINE_VISIBILITY
4199_LIBCPP_CONSTEXPR auto
4200__invoke_constexpr(_Fp&& __f, _A0&& __a0)
4201_LIBCPP_INVOKE_RETURN(_VSTD::forward<_A0>(__a0).*__f)
4202
4203template <class _Fp, class _A0,
4204          class = __enable_if_bullet5<_Fp, _A0>>
4205inline _LIBCPP_INLINE_VISIBILITY
4206auto
4207__invoke(_Fp&& __f, _A0&& __a0)
4208_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
4209
4210template <class _Fp, class _A0,
4211          class = __enable_if_bullet5<_Fp, _A0>>
4212inline _LIBCPP_INLINE_VISIBILITY
4213_LIBCPP_CONSTEXPR auto
4214__invoke_constexpr(_Fp&& __f, _A0&& __a0)
4215_LIBCPP_INVOKE_RETURN(__a0.get().*__f)
4216
4217template <class _Fp, class _A0,
4218          class = __enable_if_bullet6<_Fp, _A0>>
4219inline _LIBCPP_INLINE_VISIBILITY
4220auto
4221__invoke(_Fp&& __f, _A0&& __a0)
4222_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
4223
4224template <class _Fp, class _A0,
4225          class = __enable_if_bullet6<_Fp, _A0>>
4226inline _LIBCPP_INLINE_VISIBILITY
4227_LIBCPP_CONSTEXPR auto
4228__invoke_constexpr(_Fp&& __f, _A0&& __a0)
4229_LIBCPP_INVOKE_RETURN((*_VSTD::forward<_A0>(__a0)).*__f)
4230
4231// bullet 7
4232
4233template <class _Fp, class ..._Args>
4234inline _LIBCPP_INLINE_VISIBILITY
4235auto
4236__invoke(_Fp&& __f, _Args&& ...__args)
4237_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
4238
4239template <class _Fp, class ..._Args>
4240inline _LIBCPP_INLINE_VISIBILITY
4241_LIBCPP_CONSTEXPR auto
4242__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
4243_LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
4244
4245#undef _LIBCPP_INVOKE_RETURN
4246
4247// __invokable
4248
4249template <class _Ret, class _Fp, class ..._Args>
4250struct __invokable_r
4251    : private __check_complete<_Fp>
4252{
4253    using _Result = decltype(
4254        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...));
4255
4256    static const bool value =
4257        conditional<
4258            !is_same<_Result, __nat>::value,
4259            typename conditional<
4260                is_void<_Ret>::value,
4261                true_type,
4262                is_convertible<_Result, _Ret>
4263            >::type,
4264            false_type
4265        >::type::value;
4266};
4267
4268template <class _Fp, class ..._Args>
4269using __invokable = __invokable_r<void, _Fp, _Args...>;
4270
4271template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
4272struct __nothrow_invokable_r_imp {
4273  static const bool value = false;
4274};
4275
4276template <class _Ret, class _Fp, class ..._Args>
4277struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
4278{
4279    typedef __nothrow_invokable_r_imp _ThisT;
4280
4281    template <class _Tp>
4282    static void __test_noexcept(_Tp) noexcept;
4283
4284    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
4285        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...)));
4286};
4287
4288template <class _Ret, class _Fp, class ..._Args>
4289struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
4290{
4291    static const bool value = noexcept(
4292        _VSTD::__invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...));
4293};
4294
4295template <class _Ret, class _Fp, class ..._Args>
4296using __nothrow_invokable_r =
4297    __nothrow_invokable_r_imp<
4298            __invokable_r<_Ret, _Fp, _Args...>::value,
4299            is_void<_Ret>::value,
4300            _Ret, _Fp, _Args...
4301    >;
4302
4303template <class _Fp, class ..._Args>
4304struct __invoke_of
4305    : public enable_if<
4306        __invokable<_Fp, _Args...>::value,
4307        typename __invokable_r<void, _Fp, _Args...>::_Result>
4308{
4309};
4310
4311// result_of
4312
4313template <class _Fp, class ..._Args>
4314class _LIBCPP_TYPE_VIS_ONLY result_of<_Fp(_Args...)>
4315    : public __invoke_of<_Fp, _Args...>
4316{
4317};
4318
4319#if _LIBCPP_STD_VER > 11
4320template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
4321#endif
4322
4323#if _LIBCPP_STD_VER > 14
4324
4325// is_callable
4326
4327template <class _Fn, class _Ret = void>
4328struct _LIBCPP_TYPE_VIS_ONLY is_callable;
4329
4330template <class _Fn, class ..._Args, class _Ret>
4331struct _LIBCPP_TYPE_VIS_ONLY is_callable<_Fn(_Args...), _Ret>
4332    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
4333
4334template <class _Fn, class _Ret = void>
4335constexpr bool is_callable_v = is_callable<_Fn, _Ret>::value;
4336
4337// is_nothrow_callable
4338
4339template <class _Fn, class _Ret = void>
4340struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_callable;
4341
4342template <class _Fn, class ..._Args, class _Ret>
4343struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_callable<_Fn(_Args...), _Ret>
4344    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value>
4345{};
4346
4347template <class _Fn, class _Ret = void>
4348constexpr bool is_nothrow_callable_v = is_nothrow_callable<_Fn, _Ret>::value;
4349
4350#endif // _LIBCPP_STD_VER > 14
4351
4352#endif  // !defined(_LIBCPP_CXX03_LANG)
4353
4354template <class _Tp> struct __is_swappable;
4355template <class _Tp> struct __is_nothrow_swappable;
4356
4357template <class _Tp>
4358inline _LIBCPP_INLINE_VISIBILITY
4359#ifndef _LIBCPP_CXX03_LANG
4360typename enable_if
4361<
4362    is_move_constructible<_Tp>::value &&
4363    is_move_assignable<_Tp>::value
4364>::type
4365#else
4366void
4367#endif
4368swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
4369                                    is_nothrow_move_assignable<_Tp>::value)
4370{
4371    _Tp __t(_VSTD::move(__x));
4372    __x = _VSTD::move(__y);
4373    __y = _VSTD::move(__t);
4374}
4375
4376template<class _Tp, size_t _Np>
4377inline _LIBCPP_INLINE_VISIBILITY
4378typename enable_if<
4379    __is_swappable<_Tp>::value
4380>::type
4381swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
4382
4383template <class _ForwardIterator1, class _ForwardIterator2>
4384inline _LIBCPP_INLINE_VISIBILITY
4385void
4386iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
4387    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
4388               _NOEXCEPT_(_NOEXCEPT_(swap(*_VSTD::declval<_ForwardIterator1>(),
4389                                          *_VSTD::declval<_ForwardIterator2>())))
4390{
4391    swap(*__a, *__b);
4392}
4393
4394// __swappable
4395
4396namespace __detail
4397{
4398// ALL generic swap overloads MUST already have a declaration available at this point.
4399
4400template <class _Tp, class _Up = _Tp,
4401          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
4402struct __swappable_with
4403{
4404    template <class _LHS, class _RHS>
4405    static decltype(swap(_VSTD::declval<_LHS>(), _VSTD::declval<_RHS>()))
4406    __test_swap(int);
4407    template <class, class>
4408    static __nat __test_swap(long);
4409
4410    // Extra parens are needed for the C++03 definition of decltype.
4411    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
4412    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
4413
4414    static const bool value = !is_same<__swap1, __nat>::value
4415                           && !is_same<__swap2, __nat>::value;
4416};
4417
4418template <class _Tp, class _Up>
4419struct __swappable_with<_Tp, _Up,  false> : false_type {};
4420
4421template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
4422struct __nothrow_swappable_with {
4423  static const bool value =
4424#ifndef _LIBCPP_HAS_NO_NOEXCEPT
4425      noexcept(swap(_VSTD::declval<_Tp>(), _VSTD::declval<_Up>()))
4426  &&  noexcept(swap(_VSTD::declval<_Up>(), _VSTD::declval<_Tp>()));
4427#else
4428      false;
4429#endif
4430};
4431
4432template <class _Tp, class _Up>
4433struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
4434
4435}  // __detail
4436
4437template <class _Tp>
4438struct __is_swappable
4439    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
4440{
4441};
4442
4443template <class _Tp>
4444struct __is_nothrow_swappable
4445    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
4446{
4447};
4448
4449#if _LIBCPP_STD_VER > 14
4450
4451template <class _Tp, class _Up>
4452struct _LIBCPP_TYPE_VIS_ONLY is_swappable_with
4453    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
4454{
4455};
4456
4457template <class _Tp>
4458struct _LIBCPP_TYPE_VIS_ONLY is_swappable
4459    : public conditional<
4460        __is_referenceable<_Tp>::value,
4461        is_swappable_with<
4462            typename add_lvalue_reference<_Tp>::type,
4463            typename add_lvalue_reference<_Tp>::type>,
4464        false_type
4465    >::type
4466{
4467};
4468
4469template <class _Tp, class _Up>
4470struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_swappable_with
4471    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
4472{
4473};
4474
4475template <class _Tp>
4476struct _LIBCPP_TYPE_VIS_ONLY is_nothrow_swappable
4477    : public conditional<
4478        __is_referenceable<_Tp>::value,
4479        is_nothrow_swappable_with<
4480            typename add_lvalue_reference<_Tp>::type,
4481            typename add_lvalue_reference<_Tp>::type>,
4482        false_type
4483    >::type
4484{
4485};
4486
4487template <class _Tp, class _Up>
4488constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
4489
4490template <class _Tp>
4491constexpr bool is_swappable_v = is_swappable<_Tp>::value;
4492
4493template <class _Tp, class _Up>
4494constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
4495
4496template <class _Tp>
4497constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
4498
4499#endif // _LIBCPP_STD_VER > 14
4500
4501#ifdef _LIBCPP_UNDERLYING_TYPE
4502
4503template <class _Tp>
4504struct underlying_type
4505{
4506    typedef _LIBCPP_UNDERLYING_TYPE(_Tp) type;
4507};
4508
4509#if _LIBCPP_STD_VER > 11
4510template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4511#endif
4512
4513#else  // _LIBCPP_UNDERLYING_TYPE
4514
4515template <class _Tp, bool _Support = false>
4516struct underlying_type
4517{
4518    static_assert(_Support, "The underyling_type trait requires compiler "
4519                            "support. Either no such support exists or "
4520                            "libc++ does not know how to use it.");
4521};
4522
4523#endif // _LIBCPP_UNDERLYING_TYPE
4524
4525
4526template <class _Tp, bool = is_enum<_Tp>::value>
4527struct __sfinae_underlying_type
4528{
4529    typedef typename underlying_type<_Tp>::type type;
4530    typedef decltype(((type)1) + 0) __promoted_type;
4531};
4532
4533template <class _Tp>
4534struct __sfinae_underlying_type<_Tp, false> {};
4535
4536inline _LIBCPP_INLINE_VISIBILITY
4537int __convert_to_integral(int __val) { return __val; }
4538
4539inline _LIBCPP_INLINE_VISIBILITY
4540unsigned __convert_to_integral(unsigned __val) { return __val; }
4541
4542inline _LIBCPP_INLINE_VISIBILITY
4543long __convert_to_integral(long __val) { return __val; }
4544
4545inline _LIBCPP_INLINE_VISIBILITY
4546unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4547
4548inline _LIBCPP_INLINE_VISIBILITY
4549long long __convert_to_integral(long long __val) { return __val; }
4550
4551inline _LIBCPP_INLINE_VISIBILITY
4552unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4553
4554#ifndef _LIBCPP_HAS_NO_INT128
4555inline _LIBCPP_INLINE_VISIBILITY
4556__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4557
4558inline _LIBCPP_INLINE_VISIBILITY
4559__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4560#endif
4561
4562template <class _Tp>
4563inline _LIBCPP_INLINE_VISIBILITY
4564typename __sfinae_underlying_type<_Tp>::__promoted_type
4565__convert_to_integral(_Tp __val) { return __val; }
4566
4567#ifndef _LIBCPP_CXX03_LANG
4568
4569template <class _Tp>
4570struct __has_operator_addressof_member_imp
4571{
4572    template <class _Up>
4573        static auto __test(int)
4574            -> typename __select_2nd<decltype(_VSTD::declval<_Up>().operator&()), true_type>::type;
4575    template <class>
4576        static auto __test(long) -> false_type;
4577
4578    static const bool value = decltype(__test<_Tp>(0))::value;
4579};
4580
4581template <class _Tp>
4582struct __has_operator_addressof_free_imp
4583{
4584    template <class _Up>
4585        static auto __test(int)
4586            -> typename __select_2nd<decltype(operator&(_VSTD::declval<_Up>())), true_type>::type;
4587    template <class>
4588        static auto __test(long) -> false_type;
4589
4590    static const bool value = decltype(__test<_Tp>(0))::value;
4591};
4592
4593template <class _Tp>
4594struct __has_operator_addressof
4595    : public integral_constant<bool, __has_operator_addressof_member_imp<_Tp>::value
4596                                  || __has_operator_addressof_free_imp<_Tp>::value>
4597{};
4598
4599#endif  // _LIBCPP_CXX03_LANG
4600
4601#if _LIBCPP_STD_VER > 14
4602template <class...> using void_t = void;
4603
4604# ifndef _LIBCPP_HAS_NO_VARIADICS
4605template <class... _Args>
4606struct conjunction : __and_<_Args...> {};
4607template<class... _Args> constexpr bool conjunction_v = conjunction<_Args...>::value;
4608
4609template <class... _Args>
4610struct disjunction : __or_<_Args...> {};
4611template<class... _Args> constexpr bool disjunction_v = disjunction<_Args...>::value;
4612
4613template <class _Tp>
4614struct negation : __not_<_Tp> {};
4615template<class _Tp> constexpr bool negation_v = negation<_Tp>::value;
4616# endif // _LIBCPP_HAS_NO_VARIADICS
4617#endif  // _LIBCPP_STD_VER > 14
4618
4619// These traits are used in __tree and __hash_table
4620#ifndef _LIBCPP_CXX03_LANG
4621struct __extract_key_fail_tag {};
4622struct __extract_key_self_tag {};
4623struct __extract_key_first_tag {};
4624
4625template <class _ValTy, class _Key,
4626          class _RawValTy = typename __unconstref<_ValTy>::type>
4627struct __can_extract_key
4628    : conditional<is_same<_RawValTy, _Key>::value, __extract_key_self_tag,
4629                  __extract_key_fail_tag>::type {};
4630
4631template <class _Pair, class _Key, class _First, class _Second>
4632struct __can_extract_key<_Pair, _Key, pair<_First, _Second>>
4633    : conditional<is_same<typename remove_const<_First>::type, _Key>::value,
4634                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4635
4636// __can_extract_map_key uses true_type/false_type instead of the tags.
4637// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4638// and _ValTy == _Key.
4639template <class _ValTy, class _Key, class _ContainerValueTy,
4640          class _RawValTy = typename __unconstref<_ValTy>::type>
4641struct __can_extract_map_key
4642    : integral_constant<bool, is_same<_RawValTy, _Key>::value> {};
4643
4644// This specialization returns __extract_key_fail_tag for non-map containers
4645// because _Key == _ContainerValueTy
4646template <class _ValTy, class _Key, class _RawValTy>
4647struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4648    : false_type {};
4649
4650#endif
4651
4652_LIBCPP_END_NAMESPACE_STD
4653
4654#endif  // _LIBCPP_TYPE_TRAITS
4655