| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++03, c++11, c++14, c++17 |
| // UNSUPPORTED: libcpp-no-concepts |
| |
| // template<class F, class... Args> |
| // concept strict_weak_order; |
| |
| #include <concepts> |
| |
| // clang-format off |
| template<class F, class T, class U> |
| requires std::relation<F, T, U> |
| [[nodiscard]] constexpr bool check_subsumption() { return false; } |
| |
| template<class F, class T, class U> |
| requires std::strict_weak_order<F, T, U> && true |
| [[nodiscard]] constexpr bool check_subsumption() { return true; } |
| // clang-format on |
| |
| static_assert(check_subsumption<int (*)(int, double), int, double>()); |
| |
| struct S1 {}; |
| struct S2 {}; |
| |
| struct R { |
| bool operator()(S1, S1) const; |
| bool operator()(S1, S2) const; |
| bool operator()(S2, S1) const; |
| bool operator()(S2, S2) const; |
| }; |
| static_assert(check_subsumption<R, S1, S2>()); |
| |
| int main(int, char**) { return 0; } |