90 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// REQUIRES: std-at-least-c++2610 11// <functional>12 13// class reference_wrapper14 15// [refwrap.comparisons], comparisons16 17// friend constexpr auto operator<=>(reference_wrapper, reference_wrapper); // Since C++2618 19#include <cassert>20#include <concepts>21#include <functional>22 23#include "test_comparisons.h"24#include "test_macros.h"25// Test SFINAE.26 27static_assert(HasOperatorSpaceship<std::reference_wrapper<StrongOrder>>);28static_assert(HasOperatorSpaceship<std::reference_wrapper<WeakOrder>>);29static_assert(HasOperatorSpaceship<std::reference_wrapper<PartialOrder>>);30 31static_assert(!HasOperatorSpaceship<std::reference_wrapper<NonComparable>>);32 33// Test comparisons.34 35template <typename T, typename Order>36constexpr void test() {37 T t{47};38 39 T bigger{94};40 T smaller{82};41 42 T unordered{std::numeric_limits<int>::min()};43 44 // Identical contents45 {46 std::reference_wrapper<T> rw1{t};47 std::reference_wrapper<T> rw2{t};48 assert(testOrder(rw1, rw2, Order::equivalent));49 }50 // Less51 {52 std::reference_wrapper<T> rw1{smaller};53 std::reference_wrapper<T> rw2{bigger};54 assert(testOrder(rw1, rw2, Order::less));55 }56 // Greater57 {58 std::reference_wrapper<T> rw1{bigger};59 std::reference_wrapper<T> rw2{smaller};60 assert(testOrder(rw1, rw2, Order::greater));61 }62 // Unordered63 if constexpr (std::same_as<T, PartialOrder>) {64 std::reference_wrapper<T> rw1{bigger};65 std::reference_wrapper<T> rw2{unordered};66 assert(testOrder(rw1, rw2, Order::unordered));67 }68}69 70constexpr bool test() {71 test<int, std::strong_ordering>();72 test<StrongOrder, std::strong_ordering>();73 test<int, std::weak_ordering>();74 test<WeakOrder, std::weak_ordering>();75 test<int, std::partial_ordering>();76 test<PartialOrder, std::partial_ordering>();77 78 // `LessAndEqComp` does not have `operator<=>`. Ordering is synthesized based on `operator<`79 test<LessAndEqComp, std::weak_ordering>();80 81 return true;82}83 84int main(int, char**) {85 test();86 static_assert(test());87 88 return 0;89}90