| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| |
| // struct unreachable_sentinel_t; |
| // inline constexpr unreachable_sentinel_t unreachable_sentinel; |
| |
| #include <iterator> |
| |
| #include <cassert> |
| #include <concepts> |
| #include <type_traits> |
| |
| #include "test_macros.h" |
| |
| template<class T, class U> |
| concept weakly_equality_comparable_with = requires(const T& t, const U& u) { |
| { t == u } -> std::same_as<bool>; |
| { t != u } -> std::same_as<bool>; |
| { u == t } -> std::same_as<bool>; |
| { u != t } -> std::same_as<bool>; |
| }; |
| |
| constexpr bool test() { |
| static_assert(std::is_empty_v<std::unreachable_sentinel_t>); |
| static_assert(std::semiregular<std::unreachable_sentinel_t>); |
| |
| static_assert(std::same_as<decltype(std::unreachable_sentinel), const std::unreachable_sentinel_t>); |
| |
| auto sentinel = std::unreachable_sentinel; |
| int i = 42; |
| assert(i != sentinel); |
| assert(sentinel != i); |
| assert(!(i == sentinel)); |
| assert(!(sentinel == i)); |
| |
| assert(&i != sentinel); |
| assert(sentinel != &i); |
| assert(!(&i == sentinel)); |
| assert(!(sentinel == &i)); |
| |
| int *p = nullptr; |
| assert(p != sentinel); |
| assert(sentinel != p); |
| assert(!(p == sentinel)); |
| assert(!(sentinel == p)); |
| |
| static_assert( weakly_equality_comparable_with<std::unreachable_sentinel_t, int>); |
| static_assert( weakly_equality_comparable_with<std::unreachable_sentinel_t, int*>); |
| static_assert(!weakly_equality_comparable_with<std::unreachable_sentinel_t, void*>); |
| ASSERT_NOEXCEPT(sentinel == p); |
| ASSERT_NOEXCEPT(sentinel != p); |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |