105 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++14, c++17, c++2010 11// template<class... Args>12// constexpr explicit unexpected(in_place_t, Args&&... args);13//14// Constraints: is_constructible_v<E, Args...> is true.15//16// Effects: Direct-non-list-initializes unex with std::forward<Args>(args)....17//18// Throws: Any exception thrown by the initialization of unex.19 20#include <cassert>21#include <concepts>22#include <expected>23#include <utility>24 25#include "test_macros.h"26 27// Test Constraints:28static_assert(std::constructible_from<std::unexpected<int>, std::in_place_t, int>);29 30// !is_constructible_v<E, Args...>31struct Foo {};32static_assert(!std::constructible_from<std::unexpected<Foo>, std::in_place_t, int>);33 34// test explicit35template <class T>36void conversion_test(T);37 38template <class T, class... Args>39concept ImplicitlyConstructible = requires(Args&&... args) { conversion_test<T>({std::forward<Args>(args)...}); };40 41static_assert(ImplicitlyConstructible<int, int>);42static_assert(!ImplicitlyConstructible<std::unexpected<int>, std::in_place_t, int>);43 44struct Arg {45 int i;46 constexpr Arg(int ii) : i(ii) {}47 constexpr Arg(const Arg& other) : i(other.i) {}48 constexpr Arg(Arg&& other) : i(other.i) { other.i = 0; }49};50 51struct Error {52 Arg arg;53 constexpr explicit Error(const Arg& a) : arg(a) {}54 constexpr explicit Error(Arg&& a) : arg(std::move(a)) {}55 Error(std::initializer_list<Error>) :arg(0){ assert(false); }56};57 58constexpr bool test() {59 // lvalue60 {61 Arg a{5};62 std::unexpected<Error> unex(std::in_place, a);63 assert(unex.error().arg.i == 5);64 assert(a.i == 5);65 }66 67 // rvalue68 {69 Arg a{5};70 std::unexpected<Error> unex(std::in_place, std::move(a));71 assert(unex.error().arg.i == 5);72 assert(a.i == 0);73 }74 75 // Direct-non-list-initializes: does not trigger initializer_list overload76 {77 Error e(5);78 [[maybe_unused]] std::unexpected<Error> unex(std::in_place, e);79 }80 return true;81}82 83void testException() {84#ifndef TEST_HAS_NO_EXCEPTIONS85 struct Except {};86 87 struct Throwing {88 Throwing(int) { throw Except{}; }89 };90 91 try {92 std::unexpected<Throwing> u(std::in_place, 5);93 assert(false);94 } catch (Except) {95 }96#endif // TEST_HAS_NO_EXCEPTIONS97}98 99int main(int, char**) {100 test();101 static_assert(test());102 testException();103 return 0;104}105