96dbdd753a
* `std::predicate`
* `std::relation`
* `std::equivalence_relation`
* `std::strict_weak_order`
Implements parts of:
- P0898R3 Standard Library Concepts
- P1754 Rename concepts to standard_case for C++20, while we still can
Differential Revision: https://reviews.llvm.org/D96477
65 lines
1.9 KiB
C++
65 lines
1.9 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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 relation;
|
|
|
|
#include <concepts>
|
|
|
|
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;
|
|
};
|
|
|
|
// clang-format off
|
|
template<class F, class T, class U>
|
|
requires std::predicate<F, T, T> && std::predicate<F, T, U> &&
|
|
std::predicate<F, U, T> && std::predicate<F, U, U>
|
|
[[nodiscard]] constexpr bool check_relation_subsumes_predicate() {
|
|
return false;
|
|
}
|
|
|
|
template<class F, class T, class U>
|
|
requires std::relation<F, T, U> && true
|
|
[[nodiscard]] constexpr bool check_relation_subsumes_predicate() {
|
|
return true;
|
|
}
|
|
// clang-format on
|
|
|
|
static_assert(
|
|
check_relation_subsumes_predicate<int (*)(int, double), int, int>());
|
|
static_assert(
|
|
check_relation_subsumes_predicate<int (*)(int, double), int, double>());
|
|
static_assert(check_relation_subsumes_predicate<R, S1, S1>());
|
|
static_assert(check_relation_subsumes_predicate<R, S1, S2>());
|
|
|
|
// clang-format off
|
|
template<class F, class T, class U>
|
|
requires std::relation<F, T, T> && std::relation<F, U, U>
|
|
[[nodiscard]] constexpr bool check_relation_subsumes_itself() {
|
|
return false;
|
|
}
|
|
|
|
template<class F, class T, class U>
|
|
requires std::relation<F, T, U>
|
|
[[nodiscard]] constexpr bool check_relation_subsumes_itself() {
|
|
return true;
|
|
}
|
|
// clang-format on
|
|
|
|
static_assert(check_relation_subsumes_itself<int (*)(int, double), int, int>());
|
|
static_assert(check_relation_subsumes_itself<R, S1, S1>());
|