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//===----------------------------------------------------------------------===//
// 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;
}
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