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 10 11 // template<class... Args> 12 // constexpr explicit expected(unexpect_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 // Postconditions: has_value() is false. 19 // 20 // Throws: Any exception thrown by the initialization of unex. 21 22 #include <cassert> 23 #include <expected> 24 #include <tuple> 25 #include <type_traits> 26 #include <utility> 27 28 #include "MoveOnly.h" 29 #include "test_macros.h" 30 #include "../../types.h" 31 32 // Test Constraints: 33 static_assert(std::is_constructible_v<std::expected<int, int>, std::unexpect_t>); 34 static_assert(std::is_constructible_v<std::expected<int, int>, std::unexpect_t, int>); 35 36 // !is_constructible_v<T, Args...> 37 struct foo {}; 38 static_assert(!std::is_constructible_v<std::expected<int, foo>, std::unexpect_t, int>); 39 40 // test explicit 41 template <class T> 42 void conversion_test(T); 43 44 template <class T, class... Args> 45 concept ImplicitlyConstructible = requires(Args&&... args) { conversion_test<T>({std::forward<Args>(args)...}); }; 46 static_assert(ImplicitlyConstructible<int, int>); 47 48 static_assert(!ImplicitlyConstructible<std::expected<int, int>, std::unexpect_t>); 49 static_assert(!ImplicitlyConstructible<std::expected<int, int>, std::unexpect_t, int>); 50 51 struct CopyOnly { 52 int i; 53 constexpr CopyOnly(int ii) : i(ii) {} 54 CopyOnly(const CopyOnly&) = default; 55 CopyOnly(CopyOnly&&) = delete; 56 friend constexpr bool operator==(const CopyOnly& mi, int ii) { return mi.i == ii; } 57 }; 58 59 template <class T, class V = int> 60 constexpr void testInt() { 61 std::expected<V, T> e(std::unexpect, 5); 62 assert(!e.has_value()); 63 assert(e.error() == 5); 64 } 65 66 template <class T, class V = int> 67 constexpr void testLValue() { 68 T t(5); 69 std::expected<V, T> e(std::unexpect, t); 70 assert(!e.has_value()); 71 assert(e.error() == 5); 72 } 73 74 template <class T, class V = int> 75 constexpr void testRValue() { 76 std::expected<V, T> e(std::unexpect, T(5)); 77 assert(!e.has_value()); 78 assert(e.error() == 5); 79 } 80 81 constexpr bool test() { 82 testInt<int>(); 83 testInt<CopyOnly>(); 84 testInt<MoveOnly>(); 85 testInt<TailClobberer<1>, bool>(); 86 testLValue<int>(); 87 testLValue<CopyOnly>(); 88 testLValue<TailClobberer<1>, bool>(); 89 testRValue<int>(); 90 testRValue<MoveOnly>(); 91 testRValue<TailClobberer<1>, bool>(); 92 93 // no arg 94 { 95 std::expected<int, int> e(std::unexpect); 96 assert(!e.has_value()); 97 assert(e.error() == 0); 98 } 99 100 // one arg 101 { 102 std::expected<int, int> e(std::unexpect, 5); 103 assert(!e.has_value()); 104 assert(e.error() == 5); 105 } 106 107 // multi args 108 { 109 std::expected<int, std::tuple<int, short, MoveOnly>> e(std::unexpect, 1, short{2}, MoveOnly(3)); 110 assert(!e.has_value()); 111 assert((e.error() == std::tuple<int, short, MoveOnly>(1, short{2}, MoveOnly(3)))); 112 } 113 114 return true; 115 } 116 117 void testException() { 118 #ifndef TEST_HAS_NO_EXCEPTIONS 119 struct Throwing { 120 Throwing(int) { throw Except{}; }; 121 }; 122 123 try { 124 std::expected<int, Throwing> u(std::unexpect, 5); 125 assert(false); 126 } catch (Except) { 127 } 128 #endif // TEST_HAS_NO_EXCEPTIONS 129 } 130 131 int main(int, char**) { 132 test(); 133 static_assert(test()); 134 testException(); 135 return 0; 136 } 137