139 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 U, class G>12// constexpr explicit(!is_convertible_v<G, E>) expected(expected<U, G>&& rhs);13//14// Let GF be G15//16// Constraints:17// - is_void_v<U> is true; and18// - is_constructible_v<E, GF> is true; and19// - is_constructible_v<unexpected<E>, expected<U, G>&> is false; and20// - is_constructible_v<unexpected<E>, expected<U, G>> is false; and21// - is_constructible_v<unexpected<E>, const expected<U, G>&> is false; and22// - is_constructible_v<unexpected<E>, const expected<U, G>> is false.23//24// Effects: If rhs.has_value() is false, direct-non-list-initializes unex with std::forward<GF>(rhs.error()).25//26// Postconditions: rhs.has_value() is unchanged; rhs.has_value() == this->has_value() is true.27//28// Throws: Any exception thrown by the initialization of unex.29 30#include <cassert>31#include <concepts>32#include <expected>33#include <type_traits>34#include <utility>35 36#include "MoveOnly.h"37#include "test_macros.h"38#include "../../types.h"39 40// Test Constraints:41template <class T1, class Err1, class T2, class Err2>42concept canCstrFromExpected = std::is_constructible_v<std::expected<T1, Err1>, std::expected<T2, Err2>&&>;43 44struct CtorFromInt {45 CtorFromInt(int);46};47 48static_assert(canCstrFromExpected<void, CtorFromInt, void, int>);49 50struct NoCtorFromInt {};51 52// !is_void_v<U>53static_assert(!canCstrFromExpected<void, int, int, int>);54 55// !is_constructible_v<E, GF>56static_assert(!canCstrFromExpected<void, NoCtorFromInt, void, int>);57 58template <class T>59struct CtorFrom {60 explicit CtorFrom(int)61 requires(!std::same_as<T, int>);62 explicit CtorFrom(T);63 explicit CtorFrom(auto&&) = delete;64};65 66// Note for below 4 tests, because their E is constructible from cvref of std::expected<void, int>,67// unexpected<E> will be constructible from cvref of std::expected<void, int>68// is_constructible_v<unexpected<E>, expected<U, G>&>69static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int>&>, void, int>);70 71// is_constructible_v<unexpected<E>, expected<U, G>>72static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int>&&>, void, int>);73 74// is_constructible_v<unexpected<E>, const expected<U, G>&> is false75static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int> const&>, void, int>);76 77// is_constructible_v<unexpected<E>, const expected<U, G>>78static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int> const&&>, void, int>);79 80// test explicit81static_assert(std::is_convertible_v<std::expected<void, int>&&, std::expected<void, long>>);82 83// !is_convertible_v<GF, E>.84static_assert(std::is_constructible_v<std::expected<void, CtorFrom<int>>, std::expected<void, int>&&>);85static_assert(!std::is_convertible_v<std::expected<void, int>&&, std::expected<void, CtorFrom<int>>>);86 87struct Data {88 MoveOnly data;89 constexpr Data(MoveOnly&& m) : data(std::move(m)) {}90};91 92constexpr bool test() {93 // convert the error94 {95 std::expected<void, MoveOnly> e1(std::unexpect, 5);96 std::expected<void, Data> e2 = std::move(e1);97 assert(!e2.has_value());98 assert(e2.error().data.get() == 5);99 assert(!e1.has_value());100 assert(e1.error().get() == 0);101 }102 103 // convert TailClobberer104 {105 std::expected<void, TailClobbererNonTrivialMove<1>> e1(std::unexpect);106 std::expected<void, TailClobberer<1>> e2 = std::move(e1);107 assert(!e2.has_value());108 assert(!e1.has_value());109 }110 111 return true;112}113 114void testException() {115#ifndef TEST_HAS_NO_EXCEPTIONS116 struct ThrowingInt {117 ThrowingInt(int) { throw Except{}; }118 };119 120 // throw on converting error121 {122 const std::expected<void, int> e1(std::unexpect);123 try {124 [[maybe_unused]] std::expected<void, ThrowingInt> e2 = e1;125 assert(false);126 } catch (Except) {127 }128 }129 130#endif // TEST_HAS_NO_EXCEPTIONS131}132 133int main(int, char**) {134 test();135 static_assert(test());136 testException();137 return 0;138}139