| //===----------------------------------------------------------------------===// |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 |
| |
| // template<class U, class G> |
| // constexpr explicit(!is_convertible_v<const G&, E>) expected(const expected<U, G>& rhs); |
| // |
| // Let GF be const G& |
| // |
| // Constraints: |
| // - is_void_v<U> is true; and |
| // - is_constructible_v<E, GF> is true; and |
| // - is_constructible_v<unexpected<E>, expected<U, G>&> is false; and |
| // - is_constructible_v<unexpected<E>, expected<U, G>> is false; and |
| // - is_constructible_v<unexpected<E>, const expected<U, G>&> is false; and |
| // - is_constructible_v<unexpected<E>, const expected<U, G>> is false. |
| // |
| // Effects: If rhs.has_value() is false, direct-non-list-initializes unex with std::forward<GF>(rhs.error()). |
| // |
| // Postconditions: rhs.has_value() is unchanged; rhs.has_value() == this->has_value() is true. |
| // |
| // Throws: Any exception thrown by the initialization of unex. |
| |
| #include <cassert> |
| #include <concepts> |
| #include <expected> |
| #include <type_traits> |
| #include <utility> |
| |
| #include "test_macros.h" |
| |
| // Test Constraints: |
| template <class T1, class Err1, class T2, class Err2> |
| concept canCstrFromExpected = std::is_constructible_v<std::expected<T1, Err1>, const std::expected<T2, Err2>&>; |
| |
| struct CtorFromInt { |
| CtorFromInt(int); |
| }; |
| |
| static_assert(canCstrFromExpected<void, CtorFromInt, void, int>); |
| |
| struct NoCtorFromInt {}; |
| |
| // !is_void_v<E> |
| static_assert(!canCstrFromExpected<void, int, int, int>); |
| |
| // !is_constructible_v<E, GF> |
| static_assert(!canCstrFromExpected<void, NoCtorFromInt, void, int>); |
| |
| template <class T> |
| struct CtorFrom { |
| explicit CtorFrom(int) |
| requires(!std::same_as<T, int>); |
| explicit CtorFrom(T); |
| explicit CtorFrom(auto&&) = delete; |
| }; |
| |
| // Note for below 4 tests, because their E is constructible from cvref of std::expected<void, int>, |
| // unexpected<E> will be constructible from cvref of std::expected<void, int> |
| // is_constructible_v<unexpected<E>, expected<U, G>&> |
| static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int>&>, void, int>); |
| |
| // is_constructible_v<unexpected<E>, expected<U, G>> |
| static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int>&&>, void, int>); |
| |
| // is_constructible_v<unexpected<E>, const expected<U, G>&> is false |
| static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int> const&>, void, int>); |
| |
| // is_constructible_v<unexpected<E>, const expected<U, G>> |
| static_assert(!canCstrFromExpected<void, CtorFrom<std::expected<void, int> const&&>, void, int>); |
| |
| // test explicit |
| static_assert(std::is_convertible_v<const std::expected<void, int>&, std::expected<void, long>>); |
| |
| // !is_convertible_v<GF, E>. |
| static_assert(std::is_constructible_v<std::expected<void, CtorFrom<int>>, const std::expected<void, int>&>); |
| static_assert(!std::is_convertible_v<const std::expected<void, int>&, std::expected<void, CtorFrom<int>>>); |
| |
| struct Data { |
| int i; |
| constexpr Data(int ii) : i(ii) {} |
| }; |
| |
| constexpr bool test() { |
| // convert the error |
| { |
| const std::expected<void, int> e1(std::unexpect, 5); |
| std::expected<void, Data> e2 = e1; |
| assert(!e2.has_value()); |
| assert(e2.error().i == 5); |
| assert(!e1.has_value()); |
| assert(e1.error() == 5); |
| } |
| |
| return true; |
| } |
| |
| void testException() { |
| #ifndef TEST_HAS_NO_EXCEPTIONS |
| struct Except {}; |
| |
| struct ThrowingInt { |
| ThrowingInt(int) { throw Except{}; } |
| }; |
| |
| // throw on converting error |
| { |
| const std::expected<void, int> e1(std::unexpect); |
| try { |
| [[maybe_unused]] std::expected<void, ThrowingInt> e2 = e1; |
| assert(false); |
| } catch (Except) { |
| } |
| } |
| |
| #endif // TEST_HAS_NO_EXCEPTIONS |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| testException(); |
| return 0; |
| } |