1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: c++03, c++11, c++14, c++17
10 // UNSUPPORTED: libcpp-no-concepts
11 
12 // template<class T, class U>
13 // concept regular_invocable;
14 
15 #include <chrono>
16 #include <concepts>
17 #include <memory>
18 #include <random>
19 #include <type_traits>
20 
21 template <class R, class... Args>
22 constexpr bool check_invocable() {
23   constexpr bool result = std::regular_invocable<R(Args...), Args...>;
24   static_assert(std::regular_invocable<R(Args...) noexcept, Args...> == result);
25   static_assert(std::regular_invocable<R (*)(Args...), Args...> == result);
26   static_assert(std::regular_invocable<R (*)(Args...) noexcept, Args...> ==
27                 result);
28   static_assert(std::regular_invocable<R (&)(Args...), Args...> == result);
29   static_assert(std::regular_invocable<R (&)(Args...) noexcept, Args...> ==
30                 result);
31 
32   return result;
33 }
34 
35 static_assert(check_invocable<void>());
36 static_assert(check_invocable<void, int>());
37 static_assert(check_invocable<void, int&>());
38 static_assert(check_invocable<void, int*, double>());
39 static_assert(check_invocable<int>());
40 static_assert(check_invocable<int, int[]>());
41 
42 struct S;
43 static_assert(check_invocable<int, int S::*, std::nullptr_t>());
44 static_assert(check_invocable<int, int (S::*)(), int (S::*)(int), int>());
45 static_assert(std::regular_invocable<void (*)(int const&), int&>);
46 static_assert(std::regular_invocable<void (*)(int const&), int&&>);
47 static_assert(std::regular_invocable<void (*)(int volatile&), int&>);
48 static_assert(std::regular_invocable<void (*)(int const volatile&), int&>);
49 
50 static_assert(!std::regular_invocable<void(), int>);
51 static_assert(!std::regular_invocable<void(int)>);
52 static_assert(!std::regular_invocable<void(int*), double*>);
53 static_assert(!std::regular_invocable<void (*)(int&), double*>);
54 static_assert(std::regular_invocable<int S::*, std::unique_ptr<S> >);
55 static_assert(std::regular_invocable<int S::*, std::shared_ptr<S> >);
56 static_assert(!std::regular_invocable<void (*)(int&&), int&>);
57 static_assert(!std::regular_invocable<void (*)(int&&), int const&>);
58 
59 static_assert(!std::regular_invocable<void>);
60 static_assert(!std::regular_invocable<void*>);
61 static_assert(!std::regular_invocable<int>);
62 static_assert(!std::regular_invocable<int&>);
63 static_assert(!std::regular_invocable<int&&>);
64 
65 namespace function_objects {
66 struct function_object {
67   void operator()();
68 };
69 static_assert(std::regular_invocable<function_object>);
70 static_assert(!std::regular_invocable<function_object const>);
71 static_assert(!std::regular_invocable<function_object volatile>);
72 static_assert(!std::regular_invocable<function_object const volatile>);
73 static_assert(std::regular_invocable<function_object&>);
74 static_assert(!std::regular_invocable<function_object const&>);
75 static_assert(!std::regular_invocable<function_object volatile&>);
76 static_assert(!std::regular_invocable<function_object const volatile&>);
77 
78 struct const_function_object {
79   void operator()(int) const;
80 };
81 static_assert(std::regular_invocable<const_function_object, int>);
82 static_assert(std::regular_invocable<const_function_object const, int>);
83 static_assert(!std::regular_invocable<const_function_object volatile, int>);
84 static_assert(
85     !std::regular_invocable<const_function_object const volatile, int>);
86 static_assert(std::regular_invocable<const_function_object&, int>);
87 static_assert(std::regular_invocable<const_function_object const&, int>);
88 static_assert(!std::regular_invocable<const_function_object volatile&, int>);
89 static_assert(
90     !std::regular_invocable<const_function_object const volatile&, int>);
91 
92 struct volatile_function_object {
93   void operator()(int, int) volatile;
94 };
95 static_assert(std::regular_invocable<volatile_function_object, int, int>);
96 static_assert(
97     !std::regular_invocable<volatile_function_object const, int, int>);
98 static_assert(
99     std::regular_invocable<volatile_function_object volatile, int, int>);
100 static_assert(
101     !std::regular_invocable<volatile_function_object const volatile, int, int>);
102 static_assert(std::regular_invocable<volatile_function_object&, int, int>);
103 static_assert(
104     !std::regular_invocable<volatile_function_object const&, int, int>);
105 static_assert(
106     std::regular_invocable<volatile_function_object volatile&, int, int>);
107 static_assert(!std::regular_invocable<volatile_function_object const volatile&,
108                                       int, int>);
109 
110 struct cv_function_object {
111   void operator()(int[]) const volatile;
112 };
113 static_assert(std::regular_invocable<cv_function_object, int*>);
114 static_assert(std::regular_invocable<cv_function_object const, int*>);
115 static_assert(std::regular_invocable<cv_function_object volatile, int*>);
116 static_assert(std::regular_invocable<cv_function_object const volatile, int*>);
117 static_assert(std::regular_invocable<cv_function_object&, int*>);
118 static_assert(std::regular_invocable<cv_function_object const&, int*>);
119 static_assert(std::regular_invocable<cv_function_object volatile&, int*>);
120 static_assert(std::regular_invocable<cv_function_object const volatile&, int*>);
121 
122 struct lvalue_function_object {
123   void operator()() &;
124 };
125 static_assert(!std::regular_invocable<lvalue_function_object>);
126 static_assert(!std::regular_invocable<lvalue_function_object const>);
127 static_assert(!std::regular_invocable<lvalue_function_object volatile>);
128 static_assert(!std::regular_invocable<lvalue_function_object const volatile>);
129 static_assert(std::regular_invocable<lvalue_function_object&>);
130 static_assert(!std::regular_invocable<lvalue_function_object const&>);
131 static_assert(!std::regular_invocable<lvalue_function_object volatile&>);
132 static_assert(!std::regular_invocable<lvalue_function_object const volatile&>);
133 
134 struct lvalue_const_function_object {
135   void operator()(int) const&;
136 };
137 static_assert(std::regular_invocable<lvalue_const_function_object, int>);
138 static_assert(std::regular_invocable<lvalue_const_function_object const, int>);
139 static_assert(
140     !std::regular_invocable<lvalue_const_function_object volatile, int>);
141 static_assert(
142     !std::regular_invocable<lvalue_const_function_object const volatile, int>);
143 static_assert(std::regular_invocable<lvalue_const_function_object&, int>);
144 static_assert(std::regular_invocable<lvalue_const_function_object const&, int>);
145 static_assert(
146     !std::regular_invocable<lvalue_const_function_object volatile&, int>);
147 static_assert(
148     !std::regular_invocable<lvalue_const_function_object const volatile&, int>);
149 
150 struct lvalue_volatile_function_object {
151   void operator()(int, int) volatile&;
152 };
153 static_assert(
154     !std::regular_invocable<lvalue_volatile_function_object, int, int>);
155 static_assert(
156     !std::regular_invocable<lvalue_volatile_function_object const, int, int>);
157 static_assert(!std::regular_invocable<lvalue_volatile_function_object volatile,
158                                       int, int>);
159 static_assert(!std::regular_invocable<
160               lvalue_volatile_function_object const volatile, int, int>);
161 static_assert(
162     std::regular_invocable<lvalue_volatile_function_object&, int, int>);
163 static_assert(
164     !std::regular_invocable<lvalue_volatile_function_object const&, int, int>);
165 static_assert(std::regular_invocable<lvalue_volatile_function_object volatile&,
166                                      int, int>);
167 static_assert(!std::regular_invocable<
168               lvalue_volatile_function_object const volatile&, int, int>);
169 
170 struct lvalue_cv_function_object {
171   void operator()(int[]) const volatile&;
172 };
173 static_assert(!std::regular_invocable<lvalue_cv_function_object, int*>);
174 static_assert(!std::regular_invocable<lvalue_cv_function_object const, int*>);
175 static_assert(
176     !std::regular_invocable<lvalue_cv_function_object volatile, int*>);
177 static_assert(
178     !std::regular_invocable<lvalue_cv_function_object const volatile, int*>);
179 static_assert(std::regular_invocable<lvalue_cv_function_object&, int*>);
180 static_assert(std::regular_invocable<lvalue_cv_function_object const&, int*>);
181 static_assert(
182     std::regular_invocable<lvalue_cv_function_object volatile&, int*>);
183 static_assert(
184     std::regular_invocable<lvalue_cv_function_object const volatile&, int*>);
185 //
186 struct rvalue_function_object {
187   void operator()() &&;
188 };
189 static_assert(std::regular_invocable<rvalue_function_object>);
190 static_assert(!std::regular_invocable<rvalue_function_object const>);
191 static_assert(!std::regular_invocable<rvalue_function_object volatile>);
192 static_assert(!std::regular_invocable<rvalue_function_object const volatile>);
193 static_assert(!std::regular_invocable<rvalue_function_object&>);
194 static_assert(!std::regular_invocable<rvalue_function_object const&>);
195 static_assert(!std::regular_invocable<rvalue_function_object volatile&>);
196 static_assert(!std::regular_invocable<rvalue_function_object const volatile&>);
197 
198 struct rvalue_const_function_object {
199   void operator()(int) const&&;
200 };
201 static_assert(std::regular_invocable<rvalue_const_function_object, int>);
202 static_assert(std::regular_invocable<rvalue_const_function_object const, int>);
203 static_assert(
204     !std::regular_invocable<rvalue_const_function_object volatile, int>);
205 static_assert(
206     !std::regular_invocable<rvalue_const_function_object const volatile, int>);
207 static_assert(!std::regular_invocable<rvalue_const_function_object&, int>);
208 static_assert(
209     !std::regular_invocable<rvalue_const_function_object const&, int>);
210 static_assert(
211     !std::regular_invocable<rvalue_const_function_object volatile&, int>);
212 static_assert(
213     !std::regular_invocable<rvalue_const_function_object const volatile&, int>);
214 
215 struct rvalue_volatile_function_object {
216   void operator()(int, int) volatile&&;
217 };
218 static_assert(
219     std::regular_invocable<rvalue_volatile_function_object, int, int>);
220 static_assert(
221     !std::regular_invocable<rvalue_volatile_function_object const, int, int>);
222 static_assert(
223     std::regular_invocable<rvalue_volatile_function_object volatile, int, int>);
224 static_assert(!std::regular_invocable<
225               rvalue_volatile_function_object const volatile, int, int>);
226 static_assert(
227     !std::regular_invocable<rvalue_volatile_function_object&, int, int>);
228 static_assert(
229     !std::regular_invocable<rvalue_volatile_function_object const&, int, int>);
230 static_assert(!std::regular_invocable<rvalue_volatile_function_object volatile&,
231                                       int, int>);
232 static_assert(!std::regular_invocable<
233               rvalue_volatile_function_object const volatile&, int, int>);
234 
235 struct rvalue_cv_function_object {
236   void operator()(int[]) const volatile&&;
237 };
238 static_assert(std::regular_invocable<rvalue_cv_function_object, int*>);
239 static_assert(std::regular_invocable<rvalue_cv_function_object const, int*>);
240 static_assert(std::regular_invocable<rvalue_cv_function_object volatile, int*>);
241 static_assert(
242     std::regular_invocable<rvalue_cv_function_object const volatile, int*>);
243 static_assert(!std::regular_invocable<rvalue_cv_function_object&, int*>);
244 static_assert(!std::regular_invocable<rvalue_cv_function_object const&, int*>);
245 static_assert(
246     !std::regular_invocable<rvalue_cv_function_object volatile&, int*>);
247 static_assert(
248     !std::regular_invocable<rvalue_cv_function_object const volatile&, int*>);
249 
250 struct multiple_overloads {
251   struct A {};
252   struct B { B(int); };
253   struct AB : A, B {};
254   struct O {};
255   void operator()(A) const;
256   void operator()(B) const;
257 };
258 static_assert(std::regular_invocable<multiple_overloads, multiple_overloads::A>);
259 static_assert(std::regular_invocable<multiple_overloads, multiple_overloads::B>);
260 static_assert(std::regular_invocable<multiple_overloads, int>);
261 static_assert(!std::regular_invocable<multiple_overloads, multiple_overloads::AB>);
262 static_assert(!std::regular_invocable<multiple_overloads, multiple_overloads::O>);
263 } // namespace function_objects
264 
265 namespace pointer_to_member_functions {
266   template<class Member, class T, class... Args>
267   constexpr bool check_member_is_invocable()
268   {
269     constexpr bool result = std::regular_invocable<Member, T&&, Args...>;
270     using uncv_t = std::remove_cvref_t<T>;
271     static_assert(std::regular_invocable<Member, uncv_t*, Args...> == result);
272     static_assert(std::regular_invocable<Member, std::unique_ptr<uncv_t>, Args...> == result);
273     static_assert(std::regular_invocable<Member, std::reference_wrapper<uncv_t>, Args...> == result);
274     static_assert(!std::regular_invocable<Member, std::nullptr_t, Args...>);
275     static_assert(!std::regular_invocable<Member, int, Args...>);
276     static_assert(!std::regular_invocable<Member, int*, Args...>);
277     static_assert(!std::regular_invocable<Member, double*, Args...>);
278     struct S2 {};
279     static_assert(!std::regular_invocable<Member, S2*, Args...>);
280     return result;
281   }
282 
283 static_assert(check_member_is_invocable<int S::*, S>());
284 static_assert(std::regular_invocable<int S::*, S&>);
285 static_assert(std::regular_invocable<int S::*, S const&>);
286 static_assert(std::regular_invocable<int S::*, S volatile&>);
287 static_assert(std::regular_invocable<int S::*, S const volatile&>);
288 static_assert(std::regular_invocable<int S::*, S&&>);
289 static_assert(std::regular_invocable<int S::*, S const&&>);
290 static_assert(std::regular_invocable<int S::*, S volatile&&>);
291 static_assert(std::regular_invocable<int S::*, S const volatile&&>);
292 
293 static_assert(check_member_is_invocable<int (S::*)(int), S, int>());
294 static_assert(!check_member_is_invocable<int (S::*)(int), S>());
295 using unqualified = void (S::*)();
296 static_assert(std::regular_invocable<unqualified, S&>);
297 static_assert(!std::regular_invocable<unqualified, S const&>);
298 static_assert(!std::regular_invocable<unqualified, S volatile&>);
299 static_assert(!std::regular_invocable<unqualified, S const volatile&>);
300 static_assert(std::regular_invocable<unqualified, S&&>);
301 static_assert(!std::regular_invocable<unqualified, S const&&>);
302 static_assert(!std::regular_invocable<unqualified, S volatile&&>);
303 static_assert(!std::regular_invocable<unqualified, S const volatile&&>);
304 
305 static_assert(check_member_is_invocable<int (S::*)(double) const, S, double>());
306 using const_qualified = void (S::*)() const;
307 static_assert(std::regular_invocable<const_qualified, S&>);
308 static_assert(std::regular_invocable<const_qualified, S const&>);
309 static_assert(!std::regular_invocable<const_qualified, S volatile&>);
310 static_assert(!std::regular_invocable<const_qualified, S const volatile&>);
311 static_assert(std::regular_invocable<const_qualified, S&&>);
312 static_assert(std::regular_invocable<const_qualified, S const&&>);
313 static_assert(!std::regular_invocable<const_qualified, S volatile&&>);
314 static_assert(!std::regular_invocable<const_qualified, S const volatile&&>);
315 
316 static_assert(
317     check_member_is_invocable<int (S::*)(double[]) volatile, S, double*>());
318 using volatile_qualified = void (S::*)() volatile;
319 static_assert(std::regular_invocable<volatile_qualified, S&>);
320 static_assert(!std::regular_invocable<volatile_qualified, S const&>);
321 static_assert(std::regular_invocable<volatile_qualified, S volatile&>);
322 static_assert(!std::regular_invocable<volatile_qualified, S const volatile&>);
323 static_assert(std::regular_invocable<volatile_qualified, S&&>);
324 static_assert(!std::regular_invocable<volatile_qualified, S const&&>);
325 static_assert(std::regular_invocable<volatile_qualified, S volatile&&>);
326 static_assert(!std::regular_invocable<volatile_qualified, S const volatile&&>);
327 
328 static_assert(check_member_is_invocable<int (S::*)(int, S&) const volatile, S,
329                                         int, S&>());
330 using cv_qualified = void (S::*)() const volatile;
331 static_assert(std::regular_invocable<cv_qualified, S&>);
332 static_assert(std::regular_invocable<cv_qualified, S const&>);
333 static_assert(std::regular_invocable<cv_qualified, S volatile&>);
334 static_assert(std::regular_invocable<cv_qualified, S const volatile&>);
335 static_assert(std::regular_invocable<cv_qualified, S&&>);
336 static_assert(std::regular_invocable<cv_qualified, S const&&>);
337 static_assert(std::regular_invocable<cv_qualified, S volatile&&>);
338 static_assert(std::regular_invocable<cv_qualified, S const volatile&&>);
339 
340 static_assert(check_member_is_invocable<int (S::*)() &, S&>());
341 using lvalue_qualified = void (S::*)() &;
342 static_assert(std::regular_invocable<lvalue_qualified, S&>);
343 static_assert(!std::regular_invocable<lvalue_qualified, S const&>);
344 static_assert(!std::regular_invocable<lvalue_qualified, S volatile&>);
345 static_assert(!std::regular_invocable<lvalue_qualified, S const volatile&>);
346 static_assert(!std::regular_invocable<lvalue_qualified, S&&>);
347 static_assert(!std::regular_invocable<lvalue_qualified, S const&&>);
348 static_assert(!std::regular_invocable<lvalue_qualified, S volatile&&>);
349 static_assert(!std::regular_invocable<lvalue_qualified, S const volatile&&>);
350 
351 static_assert(check_member_is_invocable<int (S::*)() const&, S>());
352 using lvalue_const_qualified = void (S::*)() const&;
353 static_assert(std::regular_invocable<lvalue_const_qualified, S&>);
354 static_assert(std::regular_invocable<lvalue_const_qualified, S const&>);
355 static_assert(!std::regular_invocable<lvalue_const_qualified, S volatile&>);
356 static_assert(
357     !std::regular_invocable<lvalue_const_qualified, S const volatile&>);
358 static_assert(std::regular_invocable<lvalue_const_qualified, S&&>);
359 static_assert(std::regular_invocable<lvalue_const_qualified, S const&&>);
360 static_assert(!std::regular_invocable<lvalue_const_qualified, S volatile&&>);
361 static_assert(
362     !std::regular_invocable<lvalue_const_qualified, S const volatile&&>);
363 
364 static_assert(check_member_is_invocable<int (S::*)() volatile&, S&>());
365 using lvalue_volatile_qualified = void (S::*)() volatile&;
366 static_assert(std::regular_invocable<lvalue_volatile_qualified, S&>);
367 static_assert(!std::regular_invocable<lvalue_volatile_qualified, S const&>);
368 static_assert(std::regular_invocable<lvalue_volatile_qualified, S volatile&>);
369 static_assert(
370     !std::regular_invocable<lvalue_volatile_qualified, S const volatile&>);
371 static_assert(!std::regular_invocable<lvalue_volatile_qualified, S&&>);
372 static_assert(!std::regular_invocable<lvalue_volatile_qualified, S const&&>);
373 static_assert(!std::regular_invocable<lvalue_volatile_qualified, S volatile&&>);
374 static_assert(
375     !std::regular_invocable<lvalue_volatile_qualified, S const volatile&&>);
376 
377 static_assert(check_member_is_invocable<int (S::*)() const volatile&, S&>());
378 using lvalue_cv_qualified = void (S::*)() const volatile&;
379 static_assert(std::regular_invocable<lvalue_cv_qualified, S&>);
380 static_assert(std::regular_invocable<lvalue_cv_qualified, S const&>);
381 static_assert(std::regular_invocable<lvalue_cv_qualified, S volatile&>);
382 static_assert(std::regular_invocable<lvalue_cv_qualified, S const volatile&>);
383 static_assert(!std::regular_invocable<lvalue_cv_qualified, S&&>);
384 static_assert(!std::regular_invocable<lvalue_cv_qualified, S const&&>);
385 static_assert(!std::regular_invocable<lvalue_cv_qualified, S volatile&&>);
386 static_assert(!std::regular_invocable<lvalue_cv_qualified, S const volatile&&>);
387 
388 using rvalue_unqualified = void (S::*)() &&;
389 static_assert(!std::regular_invocable<rvalue_unqualified, S&>);
390 static_assert(!std::regular_invocable<rvalue_unqualified, S const&>);
391 static_assert(!std::regular_invocable<rvalue_unqualified, S volatile&>);
392 static_assert(!std::regular_invocable<rvalue_unqualified, S const volatile&>);
393 static_assert(std::regular_invocable<rvalue_unqualified, S&&>);
394 static_assert(!std::regular_invocable<rvalue_unqualified, S const&&>);
395 static_assert(!std::regular_invocable<rvalue_unqualified, S volatile&&>);
396 static_assert(!std::regular_invocable<rvalue_unqualified, S const volatile&&>);
397 
398 using rvalue_const_unqualified = void (S::*)() const&&;
399 static_assert(!std::regular_invocable<rvalue_const_unqualified, S&>);
400 static_assert(!std::regular_invocable<rvalue_const_unqualified, S const&>);
401 static_assert(!std::regular_invocable<rvalue_const_unqualified, S volatile&>);
402 static_assert(
403     !std::regular_invocable<rvalue_const_unqualified, S const volatile&>);
404 static_assert(std::regular_invocable<rvalue_const_unqualified, S&&>);
405 static_assert(std::regular_invocable<rvalue_const_unqualified, S const&&>);
406 static_assert(!std::regular_invocable<rvalue_const_unqualified, S volatile&&>);
407 static_assert(
408     !std::regular_invocable<rvalue_const_unqualified, S const volatile&&>);
409 
410 using rvalue_volatile_unqualified = void (S::*)() volatile&&;
411 static_assert(!std::regular_invocable<rvalue_volatile_unqualified, S&>);
412 static_assert(!std::regular_invocable<rvalue_volatile_unqualified, S const&>);
413 static_assert(
414     !std::regular_invocable<rvalue_volatile_unqualified, S volatile&>);
415 static_assert(
416     !std::regular_invocable<rvalue_volatile_unqualified, S const volatile&>);
417 static_assert(std::regular_invocable<rvalue_volatile_unqualified, S&&>);
418 static_assert(!std::regular_invocable<rvalue_volatile_unqualified, S const&&>);
419 static_assert(
420     std::regular_invocable<rvalue_volatile_unqualified, S volatile&&>);
421 static_assert(
422     !std::regular_invocable<rvalue_volatile_unqualified, S const volatile&&>);
423 
424 using rvalue_cv_unqualified = void (S::*)() const volatile&&;
425 static_assert(!std::regular_invocable<rvalue_cv_unqualified, S&>);
426 static_assert(!std::regular_invocable<rvalue_cv_unqualified, S const&>);
427 static_assert(!std::regular_invocable<rvalue_cv_unqualified, S volatile&>);
428 static_assert(
429     !std::regular_invocable<rvalue_cv_unqualified, S const volatile&>);
430 static_assert(std::regular_invocable<rvalue_cv_unqualified, S&&>);
431 static_assert(std::regular_invocable<rvalue_cv_unqualified, S const&&>);
432 static_assert(std::regular_invocable<rvalue_cv_unqualified, S volatile&&>);
433 static_assert(
434     std::regular_invocable<rvalue_cv_unqualified, S const volatile&&>);
435 } // namespace pointer_to_member_functions
436 
437 // Check the concept with closure types (and also check for subsumption)
438 template<class F, class... Args>
439 constexpr bool is_regular_invocable(F, Args&&...) {
440   return false;
441 }
442 
443 template<class F, class... Args>
444 requires std::invocable<F, Args...>
445 constexpr bool is_regular_invocable(F, Args&&...) {
446   return false;
447 }
448 
449 template<class F, class... Args>
450 requires std::regular_invocable<F, Args...> && true
451 constexpr bool is_regular_invocable(F, Args&&...) {
452   return true;
453 }
454 
455 static_assert(is_regular_invocable([] {}));
456 static_assert(is_regular_invocable([](int) {}, 0));
457 static_assert(is_regular_invocable([](int) {}, 0L));
458 static_assert(!is_regular_invocable([](int) {}, nullptr));
459 
460 int i = 0;
461 static_assert(is_regular_invocable([](int&) {}, i));
462