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 F, class... Args>
13 // concept predicate;
14 
15 #include <concepts>
16 
17 constexpr bool check_subsumption(std::regular_invocable auto) {
18   return false;
19 }
20 
21 // clang-format off
22 template<class F>
23 requires std::predicate<F> && true
24 constexpr bool check_subsumption(F)
25 {
26   return true;
27 }
28 // clang-format on
29 
30 static_assert(!check_subsumption([] {}));
31 static_assert(check_subsumption([] { return true; }));
32