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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
// constexpr expected& operator=(expected&& rhs) noexcept(see below);
//
// Effects:
// - If this->has_value() && rhs.has_value() is true, no effects.
// - Otherwise, if this->has_value() is true, equivalent to:
// construct_at(addressof(unex), std::move(rhs.unex));
// has_val = false;
// - Otherwise, if rhs.has_value() is true, destroys unex and sets has_val to true.
// - Otherwise, equivalent to unex = std::move(rhs.error()).
//
// Returns: *this.
//
// Remarks: The exception specification is equivalent to is_nothrow_move_constructible_v<E> && is_nothrow_move_assignable_v<E>.
//
// This operator is defined as deleted unless is_move_constructible_v<E> is true and is_move_assignable_v<E> is true.
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "../../types.h"
#include "test_macros.h"
struct NotMoveConstructible {
NotMoveConstructible(NotMoveConstructible&&) = delete;
NotMoveConstructible& operator=(NotMoveConstructible&&) = default;
};
struct NotMoveAssignable {
NotMoveAssignable(NotMoveAssignable&&) = default;
NotMoveAssignable& operator=(NotMoveAssignable&&) = delete;
};
// Test constraints
static_assert(std::is_move_assignable_v<std::expected<void, int>>);
// !is_move_assignable_v<E>
static_assert(!std::is_move_assignable_v<std::expected<void, NotMoveAssignable>>);
// !is_move_constructible_v<E>
static_assert(!std::is_move_assignable_v<std::expected<void, NotMoveConstructible>>);
// Test noexcept
struct MoveCtorMayThrow {
MoveCtorMayThrow(MoveCtorMayThrow&&) noexcept(false) {}
MoveCtorMayThrow& operator=(MoveCtorMayThrow&&) noexcept = default;
};
struct MoveAssignMayThrow {
MoveAssignMayThrow(MoveAssignMayThrow&&) noexcept = default;
MoveAssignMayThrow& operator=(MoveAssignMayThrow&&) noexcept(false) { return *this; }
};
// Test noexcept
static_assert(std::is_nothrow_move_assignable_v<std::expected<void, int>>);
// !is_nothrow_move_assignable_v<E>
static_assert(!std::is_nothrow_move_assignable_v<std::expected<void, MoveAssignMayThrow>>);
// !is_nothrow_move_constructible_v<E>
static_assert(!std::is_nothrow_move_assignable_v<std::expected<void, MoveCtorMayThrow>>);
constexpr bool test() {
// If this->has_value() && rhs.has_value() is true, no effects.
{
std::expected<void, int> e1;
std::expected<void, int> e2;
decltype(auto) x = (e1 = std::move(e2));
static_assert(std::same_as<decltype(x), std::expected<void, int>&>);
assert(&x == &e1);
assert(e1.has_value());
}
// Otherwise, if this->has_value() is true, equivalent to:
// construct_at(addressof(unex), std::move(rhs.unex));
// has_val = false;
{
Traced::state state{};
std::expected<void, Traced> e1;
std::expected<void, Traced> e2(std::unexpect, state, 5);
decltype(auto) x = (e1 = std::move(e2));
static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
assert(&x == &e1);
assert(!e1.has_value());
assert(e1.error().data_ == 5);
assert(state.moveCtorCalled);
}
// Otherwise, if rhs.has_value() is true, destroys unex and sets has_val to true.
{
Traced::state state{};
std::expected<void, Traced> e1(std::unexpect, state, 5);
std::expected<void, Traced> e2;
decltype(auto) x = (e1 = std::move(e2));
static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(state.dtorCalled);
}
// Otherwise, equivalent to unex = rhs.error().
{
Traced::state state{};
std::expected<void, Traced> e1(std::unexpect, state, 5);
std::expected<void, Traced> e2(std::unexpect, state, 10);
decltype(auto) x = (e1 = std::move(e2));
static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
assert(&x == &e1);
assert(!e1.has_value());
assert(e1.error().data_ == 10);
assert(state.moveAssignCalled);
}
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
std::expected<void, ThrowOnMoveConstruct> e1(std::in_place);
std::expected<void, ThrowOnMoveConstruct> e2(std::unexpect);
try {
e1 = std::move(e2);
assert(false);
} catch (Except) {
assert(e1.has_value());
}
#endif // TEST_HAS_NO_EXCEPTIONS
}
int main(int, char**) {
test();
static_assert(test());
testException();
return 0;
}
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