88 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// UNSUPPORTED: c++03, c++11, c++1410// <optional>11 12// template <class T, class U> constexpr bool operator<(const optional<T>& x, const U& v);13// template <class T, class U> constexpr bool operator<(const U& v, const optional<T>& x);14 15#include <optional>16 17#include "test_comparisons.h"18#include "test_macros.h"19 20#if TEST_STD_VER >= 2621 22// Test SFINAE.23static_assert(HasOperatorLessThan<std::optional<ThreeWayComparable>, int>);24static_assert(HasOperatorLessThan<std::optional<ThreeWayComparable>, ThreeWayComparable>);25 26static_assert(!HasOperatorLessThan<std::optional<NonComparable>, NonComparable>);27static_assert(!HasOperatorLessThan<std::optional<ThreeWayComparable>, NonComparable>);28static_assert(!HasOperatorLessThan<std::optional<NonComparable>, ThreeWayComparable>);29 30static_assert(HasOperatorLessThan<int, std::optional<ThreeWayComparable>>);31static_assert(HasOperatorLessThan<ThreeWayComparable, std::optional<ThreeWayComparable>>);32 33static_assert(!HasOperatorLessThan<NonComparable, std::optional<NonComparable>>);34static_assert(!HasOperatorLessThan<NonComparable, std::optional<ThreeWayComparable>>);35static_assert(!HasOperatorLessThan<ThreeWayComparable, std::optional<NonComparable>>);36 37#endif38 39using std::optional;40 41struct X {42 int i_;43 44 constexpr X(int i) : i_(i) {}45};46 47constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }48 49int main(int, char**) {50 {51 typedef X T;52 typedef optional<T> O;53 54 constexpr T val(2);55 constexpr O o1; // disengaged56 constexpr O o2{1}; // engaged57 constexpr O o3{val}; // engaged58 59 static_assert((o1 < T(1)), "");60 static_assert(!(o2 < T(1)), ""); // equal61 static_assert(!(o3 < T(1)), "");62 static_assert((o2 < val), "");63 static_assert(!(o3 < val), ""); // equal64 static_assert((o3 < T(3)), "");65 66 static_assert(!(T(1) < o1), "");67 static_assert(!(T(1) < o2), ""); // equal68 static_assert((T(1) < o3), "");69 static_assert(!(val < o2), "");70 static_assert(!(val < o3), ""); // equal71 static_assert(!(T(3) < o3), "");72 }73 {74 using O = optional<int>;75 constexpr O o1(42);76 static_assert(o1 < 101l, "");77 static_assert(!(42l < o1), "");78 }79 {80 using O = optional<const int>;81 constexpr O o1(42);82 static_assert(o1 < 101, "");83 static_assert(!(42 < o1), "");84 }85 86 return 0;87}88