87 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, const T&); // Since C++2618 19#include <cassert>20#include <concepts>21#include <functional>22 23#include "test_comparisons.h"24#include "test_macros.h"25 26// Test SFINAE.27 28static_assert(HasOperatorSpaceship<std::reference_wrapper<StrongOrder>, int>);29static_assert(HasOperatorSpaceship<std::reference_wrapper<WeakOrder>, int>);30static_assert(HasOperatorSpaceship<std::reference_wrapper<PartialOrder>, int>);31 32static_assert(!HasOperatorSpaceship<std::reference_wrapper<NonComparable>, int>);33 34// Test comparisons.35 36template <typename T, typename Order>37constexpr void test() {38 T t{47};39 40 T bigger{94};41 T smaller{82};42 43 T unordered{std::numeric_limits<int>::min()};44 45 // Identical contents46 {47 std::reference_wrapper<T> rw1{t};48 assert(testOrder(rw1, t, Order::equivalent));49 }50 // Less51 {52 std::reference_wrapper<T> rw1{smaller};53 assert(testOrder(rw1, bigger, Order::less));54 }55 // Greater56 {57 std::reference_wrapper<T> rw1{bigger};58 assert(testOrder(rw1, smaller, Order::greater));59 }60 // Unordered61 if constexpr (std::same_as<T, PartialOrder>) {62 std::reference_wrapper<T> rw1{bigger};63 assert(testOrder(rw1, unordered, Order::unordered));64 }65}66 67constexpr bool test() {68 test<int, std::strong_ordering>();69 test<StrongOrder, std::strong_ordering>();70 test<int, std::weak_ordering>();71 test<WeakOrder, std::weak_ordering>();72 test<int, std::partial_ordering>();73 test<PartialOrder, std::partial_ordering>();74 75 // `LessAndEqComp` does not have `operator<=>`. Ordering is synthesized based on `operator<`76 test<LessAndEqComp, std::weak_ordering>();77 78 return true;79}80 81int main(int, char**) {82 test();83 static_assert(test());84 85 return 0;86}87