1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_TYPE_TRAITS
11#define _LIBCPP_TYPE_TRAITS
12
13/*
14 type_traits synopsis
15
16namespace std
17{
18
19 // helper class:
20 template <class T, T v> struct integral_constant;
21 typedef integral_constant<bool, true> true_type; // since C++11
22 typedef integral_constant<bool, false> false_type; // since C++11
23
24 template <bool B>
25 using bool_constant = integral_constant<bool, B>; // since C++17
26
27 // helper traits
28 template <bool, class T = void> struct enable_if;
29 template <bool, class T, class F> struct conditional;
30
31 // Primary classification traits:
32 template <class T> struct is_void;
33 template <class T> struct is_null_pointer; // since C++14
34 template <class T> struct is_integral;
35 template <class T> struct is_floating_point;
36 template <class T> struct is_array;
37 template <class T> struct is_pointer;
38 template <class T> struct is_lvalue_reference;
39 template <class T> struct is_rvalue_reference;
40 template <class T> struct is_member_object_pointer;
41 template <class T> struct is_member_function_pointer;
42 template <class T> struct is_enum;
43 template <class T> struct is_union;
44 template <class T> struct is_class;
45 template <class T> struct is_function;
46
47 // Secondary classification traits:
48 template <class T> struct is_reference;
49 template <class T> struct is_arithmetic;
50 template <class T> struct is_fundamental;
51 template <class T> struct is_member_pointer;
52 template <class T> struct is_scoped_enum; // since C++23
53 template <class T> struct is_scalar;
54 template <class T> struct is_object;
55 template <class T> struct is_compound;
56
57 // Const-volatile properties and transformations:
58 template <class T> struct is_const;
59 template <class T> struct is_volatile;
60 template <class T> struct remove_const;
61 template <class T> struct remove_volatile;
62 template <class T> struct remove_cv;
63 template <class T> struct add_const;
64 template <class T> struct add_volatile;
65 template <class T> struct add_cv;
66
67 // Reference transformations:
68 template <class T> struct remove_reference;
69 template <class T> struct add_lvalue_reference;
70 template <class T> struct add_rvalue_reference;
71
72 // Pointer transformations:
73 template <class T> struct remove_pointer;
74 template <class T> struct add_pointer;
75
76 template<class T> struct type_identity; // since C++20
77 template<class T>
78 using type_identity_t = typename type_identity<T>::type; // since C++20
79
80 // Integral properties:
81 template <class T> struct is_signed;
82 template <class T> struct is_unsigned;
83 template <class T> struct make_signed;
84 template <class T> struct make_unsigned;
85
86 // Array properties and transformations:
87 template <class T> struct rank;
88 template <class T, unsigned I = 0> struct extent;
89 template <class T> struct remove_extent;
90 template <class T> struct remove_all_extents;
91
92 template <class T> struct is_bounded_array; // since C++20
93 template <class T> struct is_unbounded_array; // since C++20
94
95 // Member introspection:
96 template <class T> struct is_trivial; // deprecated in C++26
97 template <class T> struct is_pod; // deprecated in C++20
98 template <class T> struct is_trivially_copyable;
99 template <class T> struct is_standard_layout;
100 template <class T> struct is_literal_type; // deprecated in C++17; removed in C++20
101 template <class T> struct is_empty;
102 template <class T> struct is_polymorphic;
103 template <class T> struct is_abstract;
104 template <class T> struct is_final; // since C++14
105 template <class T> struct is_aggregate; // since C++17
106
107 template <class T, class... Args> struct is_constructible;
108 template <class T> struct is_default_constructible;
109 template <class T> struct is_copy_constructible;
110 template <class T> struct is_move_constructible;
111 template <class T, class U> struct is_assignable;
112 template <class T> struct is_copy_assignable;
113 template <class T> struct is_move_assignable;
114 template <class T, class U> struct is_swappable_with; // since C++17
115 template <class T> struct is_swappable; // since C++17
116 template <class T> struct is_destructible;
117
118 template <class T, class... Args> struct is_trivially_constructible;
119 template <class T> struct is_trivially_default_constructible;
120 template <class T> struct is_trivially_copy_constructible;
121 template <class T> struct is_trivially_move_constructible;
122 template <class T, class U> struct is_trivially_assignable;
123 template <class T> struct is_trivially_copy_assignable;
124 template <class T> struct is_trivially_move_assignable;
125 template <class T> struct is_trivially_destructible;
126
127 template <class T, class... Args> struct is_nothrow_constructible;
128 template <class T> struct is_nothrow_default_constructible;
129 template <class T> struct is_nothrow_copy_constructible;
130 template <class T> struct is_nothrow_move_constructible;
131 template <class T, class U> struct is_nothrow_assignable;
132 template <class T> struct is_nothrow_copy_assignable;
133 template <class T> struct is_nothrow_move_assignable;
134 template <class T, class U>
135 struct is_nothrow_swappable_with; // since C++17
136 template <class T>
137 struct is_nothrow_swappable; // since C++17
138 template <class T> struct is_nothrow_destructible;
139
140 template <class T> struct is_implicit_lifetime; // since C++23
141
142 template <class T> struct has_virtual_destructor;
143
144 template <class T>
145 struct has_unique_object_representations; // since C++17
146
147 template<class T, class U>
148 struct reference_constructs_from_temporary; // since C++23
149 template<class T, class U>
150 struct reference_converts_from_temporary; // since C++23
151
152 // Relationships between types:
153 template <class T, class U> struct is_same;
154 template <class Base, class Derived> struct is_base_of;
155 template <class Base, class Derived>
156 struct is_virtual_base_of; // since C++26
157
158 template <class From, class To> struct is_convertible;
159 template <class From, class To>
160 struct is_nothrow_convertible; // since C++20
161
162 template <class Fn, class... ArgTypes> struct is_invocable; // since C++17
163 template <class R, class Fn, class... ArgTypes>
164 struct is_invocable_r; // since C++17
165
166 template <class Fn, class... ArgTypes>
167 struct is_nothrow_invocable; // since C++17
168 template <class R, class Fn, class... ArgTypes>
169 struct is_nothrow_invocable_r; // since C++17
170
171 // Alignment properties and transformations:
172 template <class T> struct alignment_of;
173 template <size_t Len, size_t Align = most_stringent_alignment_requirement>
174 struct aligned_storage; // deprecated in C++23
175 template <size_t Len, class... Types> struct aligned_union; // deprecated in C++23
176 template <class T> struct remove_cvref; // since C++20
177
178 template <class T> struct decay;
179 template <class... T> struct common_type;
180 template <class T> struct underlying_type;
181 template <class> struct result_of; // undefined; deprecated in C++17; removed in C++20
182 template <class Fn, class... ArgTypes>
183 struct result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
184 template <class Fn, class... ArgTypes>
185 struct invoke_result; // since C++17
186
187 // const-volatile modifications:
188 template <class T>
189 using remove_const_t = typename remove_const<T>::type; // since C++14
190 template <class T>
191 using remove_volatile_t
192 = typename remove_volatile<T>::type; // since C++14
193 template <class T>
194 using remove_cv_t = typename remove_cv<T>::type; // since C++14
195 template <class T>
196 using add_const_t = typename add_const<T>::type; // since C++14
197 template <class T>
198 using add_volatile_t = typename add_volatile<T>::type; // since C++14
199 template <class T>
200 using add_cv_t = typename add_cv<T>::type; // since C++14
201
202 // reference modifications:
203 template <class T>
204 using remove_reference_t
205 = typename remove_reference<T>::type; // since C++14
206 template <class T>
207 using add_lvalue_reference_t
208 = typename add_lvalue_reference<T>::type; // since C++14
209 template <class T>
210 using add_rvalue_reference_t
211 = typename add_rvalue_reference<T>::type; // since C++14
212
213 // sign modifications:
214 template <class T>
215 using make_signed_t = typename make_signed<T>::type; // since C++14
216 template <class T>
217 using make_unsigned_t = typename make_unsigned<T>::type; // since C++14
218
219 // array modifications:
220 template <class T>
221 using remove_extent_t
222 = typename remove_extent<T>::type; // since C++14
223 template <class T>
224 using remove_all_extents_t
225 = typename remove_all_extents<T>::type; // since C++14
226
227 template <class T>
228 inline constexpr bool is_bounded_array_v
229 = is_bounded_array<T>::value; // since C++20
230 inline constexpr bool is_unbounded_array_v
231 = is_unbounded_array<T>::value; // since C++20
232
233 // pointer modifications:
234 template <class T>
235 using remove_pointer_t
236 = typename remove_pointer<T>::type; // since C++14
237 template <class T>
238 using add_pointer_t = typename add_pointer<T>::type; // since C++14
239
240 // other transformations:
241 template <size_t Len, size_t Align=default-alignment>
242 using aligned_storage_t
243 = typename aligned_storage<Len,Align>::type; // since C++14
244 template <size_t Len, class... Types>
245 using aligned_union_t
246 = typename aligned_union<Len,Types...>::type; // since C++14
247 template <class T>
248 using remove_cvref_t
249 = typename remove_cvref<T>::type; // since C++20
250 template <class T>
251 using decay_t = typename decay<T>::type; // since C++14
252 template <bool b, class T=void>
253 using enable_if_t = typename enable_if<b,T>::type; // since C++14
254 template <bool b, class T, class F>
255 using conditional_t
256 = typename conditional<b,T,F>::type; // since C++14
257 template <class... T>
258 using common_type_t
259 = typename common_type<T...>::type; // since C++14
260 template <class T>
261 using underlying_type_t
262 = typename underlying_type<T>::type; // since C++14
263 template <class T>
264 using result_of_t = typename result_of<T>::type; // since C++14; deprecated in C++17; removed in C++20
265 template <class Fn, class... ArgTypes>
266 using invoke_result_t
267 = typename invoke_result<Fn, ArgTypes...>::type; // since C++17
268
269 template <class...>
270 using void_t = void; // since C++17
271
272 // See C++14 20.10.4.1, primary type categories
273 template <class T> inline constexpr bool is_void_v
274 = is_void<T>::value; // since C++17
275 template <class T> inline constexpr bool is_null_pointer_v
276 = is_null_pointer<T>::value; // since C++17
277 template <class T> inline constexpr bool is_integral_v
278 = is_integral<T>::value; // since C++17
279 template <class T> inline constexpr bool is_floating_point_v
280 = is_floating_point<T>::value; // since C++17
281 template <class T> inline constexpr bool is_array_v
282 = is_array<T>::value; // since C++17
283 template <class T> inline constexpr bool is_pointer_v
284 = is_pointer<T>::value; // since C++17
285 template <class T> inline constexpr bool is_lvalue_reference_v
286 = is_lvalue_reference<T>::value; // since C++17
287 template <class T> inline constexpr bool is_rvalue_reference_v
288 = is_rvalue_reference<T>::value; // since C++17
289 template <class T> inline constexpr bool is_member_object_pointer_v
290 = is_member_object_pointer<T>::value; // since C++17
291 template <class T> inline constexpr bool is_member_function_pointer_v
292 = is_member_function_pointer<T>::value; // since C++17
293 template <class T> inline constexpr bool is_enum_v
294 = is_enum<T>::value; // since C++17
295 template <class T> inline constexpr bool is_union_v
296 = is_union<T>::value; // since C++17
297 template <class T> inline constexpr bool is_class_v
298 = is_class<T>::value; // since C++17
299 template <class T> inline constexpr bool is_function_v
300 = is_function<T>::value; // since C++17
301
302 // See C++14 20.10.4.2, composite type categories
303 template <class T> inline constexpr bool is_reference_v
304 = is_reference<T>::value; // since C++17
305 template <class T> inline constexpr bool is_arithmetic_v
306 = is_arithmetic<T>::value; // since C++17
307 template <class T> inline constexpr bool is_fundamental_v
308 = is_fundamental<T>::value; // since C++17
309 template <class T> inline constexpr bool is_object_v
310 = is_object<T>::value; // since C++17
311 template <class T> inline constexpr bool is_scalar_v
312 = is_scalar<T>::value; // since C++17
313 template <class T> inline constexpr bool is_compound_v
314 = is_compound<T>::value; // since C++17
315 template <class T> inline constexpr bool is_member_pointer_v
316 = is_member_pointer<T>::value; // since C++17
317 template <class T> inline constexpr bool is_scoped_enum_v
318 = is_scoped_enum<T>::value; // since C++23
319
320 // See C++14 20.10.4.3, type properties
321 template <class T> inline constexpr bool is_const_v
322 = is_const<T>::value; // since C++17
323 template <class T> inline constexpr bool is_volatile_v
324 = is_volatile<T>::value; // since C++17
325 template <class T> inline constexpr bool is_trivial_v
326 = is_trivial<T>::value; // since C++17; deprecated in C++26
327 template <class T> inline constexpr bool is_trivially_copyable_v
328 = is_trivially_copyable<T>::value; // since C++17
329 template <class T> inline constexpr bool is_standard_layout_v
330 = is_standard_layout<T>::value; // since C++17
331 template <class T> inline constexpr bool is_pod_v
332 = is_pod<T>::value; // since C++17; deprecated in C++20
333 template <class T> inline constexpr bool is_literal_type_v
334 = is_literal_type<T>::value; // since C++17; deprecated in C++17; removed in C++20
335 template <class T> inline constexpr bool is_empty_v
336 = is_empty<T>::value; // since C++17
337 template <class T> inline constexpr bool is_polymorphic_v
338 = is_polymorphic<T>::value; // since C++17
339 template <class T> inline constexpr bool is_abstract_v
340 = is_abstract<T>::value; // since C++17
341 template <class T> inline constexpr bool is_final_v
342 = is_final<T>::value; // since C++17
343 template <class T> inline constexpr bool is_aggregate_v
344 = is_aggregate<T>::value; // since C++17
345 template <class T> inline constexpr bool is_signed_v
346 = is_signed<T>::value; // since C++17
347 template <class T> inline constexpr bool is_unsigned_v
348 = is_unsigned<T>::value; // since C++17
349 template <class T, class... Args> inline constexpr bool is_constructible_v
350 = is_constructible<T, Args...>::value; // since C++17
351 template <class T> inline constexpr bool is_default_constructible_v
352 = is_default_constructible<T>::value; // since C++17
353 template <class T> inline constexpr bool is_copy_constructible_v
354 = is_copy_constructible<T>::value; // since C++17
355 template <class T> inline constexpr bool is_move_constructible_v
356 = is_move_constructible<T>::value; // since C++17
357 template <class T, class U> inline constexpr bool is_assignable_v
358 = is_assignable<T, U>::value; // since C++17
359 template <class T> inline constexpr bool is_copy_assignable_v
360 = is_copy_assignable<T>::value; // since C++17
361 template <class T> inline constexpr bool is_move_assignable_v
362 = is_move_assignable<T>::value; // since C++17
363 template <class T, class U> inline constexpr bool is_swappable_with_v
364 = is_swappable_with<T, U>::value; // since C++17
365 template <class T> inline constexpr bool is_swappable_v
366 = is_swappable<T>::value; // since C++17
367 template <class T> inline constexpr bool is_destructible_v
368 = is_destructible<T>::value; // since C++17
369 template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
370 = is_trivially_constructible<T, Args...>::value; // since C++17
371 template <class T> inline constexpr bool is_trivially_default_constructible_v
372 = is_trivially_default_constructible<T>::value; // since C++17
373 template <class T> inline constexpr bool is_trivially_copy_constructible_v
374 = is_trivially_copy_constructible<T>::value; // since C++17
375 template <class T> inline constexpr bool is_trivially_move_constructible_v
376 = is_trivially_move_constructible<T>::value; // since C++17
377 template <class T, class U> inline constexpr bool is_trivially_assignable_v
378 = is_trivially_assignable<T, U>::value; // since C++17
379 template <class T> inline constexpr bool is_trivially_copy_assignable_v
380 = is_trivially_copy_assignable<T>::value; // since C++17
381 template <class T> inline constexpr bool is_trivially_move_assignable_v
382 = is_trivially_move_assignable<T>::value; // since C++17
383 template <class T> inline constexpr bool is_trivially_destructible_v
384 = is_trivially_destructible<T>::value; // since C++17
385 template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
386 = is_nothrow_constructible<T, Args...>::value; // since C++17
387 template <class T> inline constexpr bool is_nothrow_default_constructible_v
388 = is_nothrow_default_constructible<T>::value; // since C++17
389 template <class T> inline constexpr bool is_nothrow_copy_constructible_v
390 = is_nothrow_copy_constructible<T>::value; // since C++17
391 template <class T> inline constexpr bool is_nothrow_move_constructible_v
392 = is_nothrow_move_constructible<T>::value; // since C++17
393 template <class T, class U> inline constexpr bool is_nothrow_assignable_v
394 = is_nothrow_assignable<T, U>::value; // since C++17
395 template <class T> inline constexpr bool is_nothrow_copy_assignable_v
396 = is_nothrow_copy_assignable<T>::value; // since C++17
397 template <class T> inline constexpr bool is_nothrow_move_assignable_v
398 = is_nothrow_move_assignable<T>::value; // since C++17
399 template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
400 = is_nothrow_swappable_with<T, U>::value; // since C++17
401 template <class T> inline constexpr bool is_nothrow_swappable_v
402 = is_nothrow_swappable<T>::value; // since C++17
403 template <class T> inline constexpr bool is_nothrow_destructible_v
404 = is_nothrow_destructible<T>::value; // since C++17
405 template <class T> inline constexpr bool is_implicit_lifetime_v
406 = is_implicit_lifetime<T>::value; // since C++23
407 template <class T> inline constexpr bool has_virtual_destructor_v
408 = has_virtual_destructor<T>::value; // since C++17
409 template<class T> inline constexpr bool has_unique_object_representations_v
410 = has_unique_object_representations<T>::value; // since C++17
411 template<class T, class U>
412 constexpr bool reference_constructs_from_temporary_v
413 = reference_constructs_from_temporary<T, U>::value; // since C++23
414 template<class T, class U>
415 constexpr bool reference_converts_from_temporary_v
416 = reference_converts_from_temporary<T, U>::value; // since C++23
417
418 // See C++14 20.10.5, type property queries
419 template <class T> inline constexpr size_t alignment_of_v
420 = alignment_of<T>::value; // since C++17
421 template <class T> inline constexpr size_t rank_v
422 = rank<T>::value; // since C++17
423 template <class T, unsigned I = 0> inline constexpr size_t extent_v
424 = extent<T, I>::value; // since C++17
425
426 // See C++14 20.10.6, type relations
427 template <class T, class U> inline constexpr bool is_same_v
428 = is_same<T, U>::value; // since C++17
429 template <class Base, class Derived> inline constexpr bool is_base_of_v
430 = is_base_of<Base, Derived>::value; // since C++17
431 template <class Base, class Derived> inline constexpr bool is_virtual_base_of_v
432 = is_virtual_base_of<Base, Derived>::value; // since C++26
433 template <class From, class To> inline constexpr bool is_convertible_v
434 = is_convertible<From, To>::value; // since C++17
435 template <class From, class To> inline constexpr bool is_nothrow_convertible_v
436 = is_nothrow_convertible<From, To>::value; // since C++20
437 template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
438 = is_invocable<Fn, ArgTypes...>::value; // since C++17
439 template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
440 = is_invocable_r<R, Fn, ArgTypes...>::value; // since C++17
441 template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
442 = is_nothrow_invocable<Fn, ArgTypes...>::value; // since C++17
443 template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
444 = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value; // since C++17
445
446 // [meta.logical], logical operator traits:
447 template<class... B> struct conjunction; // since C++17
448 template<class... B> inline constexpr bool conjunction_v
449 = conjunction<B...>::value; // since C++17
450 template<class... B> struct disjunction; // since C++17
451 template<class... B> inline constexpr bool disjunction_v
452 = disjunction<B...>::value; // since C++17
453 template<class B> struct negation; // since C++17
454 template<class B> inline constexpr bool negation_v
455 = negation<B>::value; // since C++17
456
457 // [meta.const.eval], constant evaluation context
458 constexpr bool is_constant_evaluated() noexcept; // C++20
459 template<class T>
460 consteval bool is_within_lifetime(const T*) noexcept; // C++26
461}
462
463*/
464
465#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
466# include <__cxx03/type_traits>
467#else
468# include <__config>
469# include <__type_traits/add_cv_quals.h>
470# include <__type_traits/add_pointer.h>
471# include <__type_traits/add_reference.h>
472# include <__type_traits/aligned_storage.h>
473# include <__type_traits/aligned_union.h>
474# include <__type_traits/alignment_of.h>
475# include <__type_traits/common_type.h>
476# include <__type_traits/conditional.h>
477# include <__type_traits/decay.h>
478# include <__type_traits/enable_if.h>
479# include <__type_traits/extent.h>
480# include <__type_traits/has_virtual_destructor.h>
481# include <__type_traits/integral_constant.h>
482# include <__type_traits/is_abstract.h>
483# include <__type_traits/is_arithmetic.h>
484# include <__type_traits/is_array.h>
485# include <__type_traits/is_assignable.h>
486# include <__type_traits/is_base_of.h>
487# include <__type_traits/is_class.h>
488# include <__type_traits/is_compound.h>
489# include <__type_traits/is_const.h>
490# include <__type_traits/is_constructible.h>
491# include <__type_traits/is_convertible.h>
492# include <__type_traits/is_destructible.h>
493# include <__type_traits/is_empty.h>
494# include <__type_traits/is_enum.h>
495# include <__type_traits/is_floating_point.h>
496# include <__type_traits/is_function.h>
497# include <__type_traits/is_fundamental.h>
498# include <__type_traits/is_integral.h>
499# include <__type_traits/is_literal_type.h>
500# include <__type_traits/is_member_pointer.h>
501# include <__type_traits/is_nothrow_assignable.h>
502# include <__type_traits/is_nothrow_constructible.h>
503# include <__type_traits/is_nothrow_destructible.h>
504# include <__type_traits/is_object.h>
505# include <__type_traits/is_pod.h>
506# include <__type_traits/is_pointer.h>
507# include <__type_traits/is_polymorphic.h>
508# include <__type_traits/is_reference.h>
509# include <__type_traits/is_same.h>
510# include <__type_traits/is_scalar.h>
511# include <__type_traits/is_signed.h>
512# include <__type_traits/is_standard_layout.h>
513# include <__type_traits/is_trivial.h>
514# include <__type_traits/is_trivially_assignable.h>
515# include <__type_traits/is_trivially_constructible.h>
516# include <__type_traits/is_trivially_copyable.h>
517# include <__type_traits/is_trivially_destructible.h>
518# include <__type_traits/is_union.h>
519# include <__type_traits/is_unsigned.h>
520# include <__type_traits/is_void.h>
521# include <__type_traits/is_volatile.h>
522# include <__type_traits/make_signed.h>
523# include <__type_traits/make_unsigned.h>
524# include <__type_traits/rank.h>
525# include <__type_traits/remove_all_extents.h>
526# include <__type_traits/remove_const.h>
527# include <__type_traits/remove_cv.h>
528# include <__type_traits/remove_extent.h>
529# include <__type_traits/remove_pointer.h>
530# include <__type_traits/remove_reference.h>
531# include <__type_traits/remove_volatile.h>
532# include <__type_traits/result_of.h>
533# include <__type_traits/underlying_type.h>
534
535# if _LIBCPP_STD_VER >= 14
536# include <__type_traits/is_final.h>
537# include <__type_traits/is_null_pointer.h>
538# endif
539
540# if _LIBCPP_STD_VER >= 17
541# include <__type_traits/conjunction.h>
542# include <__type_traits/disjunction.h>
543# include <__type_traits/has_unique_object_representation.h>
544# include <__type_traits/invoke.h>
545# include <__type_traits/is_aggregate.h>
546# include <__type_traits/is_swappable.h>
547# include <__type_traits/negation.h>
548# include <__type_traits/void_t.h>
549# endif
550
551# if _LIBCPP_STD_VER >= 20
552# include <__type_traits/common_reference.h>
553# include <__type_traits/is_constant_evaluated.h>
554# include <__type_traits/type_identity.h>
555# include <__type_traits/unwrap_ref.h>
556# endif
557
558# if _LIBCPP_STD_VER >= 23
559# include <__type_traits/is_implicit_lifetime.h>
560# include <__type_traits/reference_constructs_from_temporary.h>
561# include <__type_traits/reference_converts_from_temporary.h>
562# endif
563
564# if _LIBCPP_STD_VER >= 26
565# include <__type_traits/is_within_lifetime.h>
566# endif
567
568# include <version>
569
570# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
571# pragma GCC system_header
572# endif
573#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
574
575#endif // _LIBCPP_TYPE_TRAITS