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-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
10
11// <functional>
12
13// class reference_wrapper
14
15// [refwrap.comparisons], comparisons
16
17// friend constexpr auto operator<=>(reference_wrapper, const T&); // Since C++26
18
19#include <cassert>
20#include <concepts>
21#include <functional>
22
23#include "test_comparisons.h"
24#include "test_macros.h"
25
26#include "helper_concepts.h"
27#include "helper_types.h"
28
29// Test SFINAE.
30
31static_assert(HasSpaceshipOperatorWithInt<std::reference_wrapper<StrongOrder>>);
32static_assert(HasSpaceshipOperatorWithInt<std::reference_wrapper<WeakOrder>>);
33static_assert(HasSpaceshipOperatorWithInt<std::reference_wrapper<PartialOrder>>);
34
35static_assert(!HasSpaceshipOperatorWithInt<std::reference_wrapper<NonComparable>>);
36
37// Test comparisons.
38
39template <typename T, typename Order>
40constexpr void test() {
41 T t{47};
42
43 T bigger{94};
44 T smaller{82};
45
46 T unordered{std::numeric_limits<int>::min()};
47
48 // Identical contents
49 {
50 std::reference_wrapper<T> rw1{t};
51 assert(testOrder(rw1, t, Order::equivalent));
52 }
53 // Less
54 {
55 std::reference_wrapper<T> rw1{smaller};
56 assert(testOrder(rw1, bigger, Order::less));
57 }
58 // Greater
59 {
60 std::reference_wrapper<T> rw1{bigger};
61 assert(testOrder(rw1, smaller, Order::greater));
62 }
63 // Unordered
64 if constexpr (std::same_as<T, PartialOrder>) {
65 std::reference_wrapper<T> rw1{bigger};
66 assert(testOrder(rw1, unordered, 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

source code of libcxx/test/std/utilities/function.objects/refwrap/refwrap.comparissons/compare.three_way.refwrap.const_ref.pass.cpp