//===----------------------------------------------------------------------===//
//
// 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=(const expected& rhs);
//
// Effects:
// - If this->has_value() && rhs.has_value() is true, equivalent to val = *rhs.
// - Otherwise, if this->has_value() is true, equivalent to:
// reinit-expected(unex, val, rhs.error())
// - Otherwise, if rhs.has_value() is true, equivalent to:
// reinit-expected(val, unex, *rhs)
// - Otherwise, equivalent to unex = rhs.error().
//
// - Then, if no exception was thrown, equivalent to: has_val = rhs.has_value(); return *this;
//
// Returns: *this.
//
// Remarks: This operator is defined as deleted unless:
// - is_copy_assignable_v<T> is true and
// - is_copy_constructible_v<T> is true and
// - is_copy_assignable_v<E> is true and
// - is_copy_constructible_v<E> is true and
// - is_nothrow_move_constructible_v<T> || is_nothrow_move_constructible_v<E> is true.
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "../../types.h"
#include "test_macros.h"
struct NotCopyConstructible {
NotCopyConstructible(const NotCopyConstructible&) = delete;
NotCopyConstructible& operator=(const NotCopyConstructible&) = default;
};
struct NotCopyAssignable {
NotCopyAssignable(const NotCopyAssignable&) = default;
NotCopyAssignable& operator=(const NotCopyAssignable&) = delete;
};
struct MoveMayThrow {
MoveMayThrow(MoveMayThrow const&) = default;
MoveMayThrow& operator=(const MoveMayThrow&) = default;
MoveMayThrow(MoveMayThrow&&) noexcept(false) {}
MoveMayThrow& operator=(MoveMayThrow&&) noexcept(false) { return *this; }
};
// Test constraints
static_assert(std::is_copy_assignable_v<std::expected<int, int>>);
// !is_copy_assignable_v<T>
static_assert(!std::is_copy_assignable_v<std::expected<NotCopyAssignable, int>>);
// !is_copy_constructible_v<T>
static_assert(!std::is_copy_assignable_v<std::expected<NotCopyConstructible, int>>);
// !is_copy_assignable_v<E>
static_assert(!std::is_copy_assignable_v<std::expected<int, NotCopyAssignable>>);
// !is_copy_constructible_v<E>
static_assert(!std::is_copy_assignable_v<std::expected<int, NotCopyConstructible>>);
// !is_nothrow_move_constructible_v<T> && is_nothrow_move_constructible_v<E>
static_assert(std::is_copy_assignable_v<std::expected<MoveMayThrow, int>>);
// is_nothrow_move_constructible_v<T> && !is_nothrow_move_constructible_v<E>
static_assert(std::is_copy_assignable_v<std::expected<int, MoveMayThrow>>);
// !is_nothrow_move_constructible_v<T> && !is_nothrow_move_constructible_v<E>
static_assert(!std::is_copy_assignable_v<std::expected<MoveMayThrow, MoveMayThrow>>);
constexpr bool test() {
// If this->has_value() && rhs.has_value() is true, equivalent to val = *rhs.
{
Traced::state oldState{};
Traced::state newState{};
std::expected<Traced, int> e1(std::in_place, oldState, 5);
const std::expected<Traced, int> e2(std::in_place, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<Traced, int>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(oldState.copyAssignCalled);
}
// - Otherwise, if this->has_value() is true, equivalent to:
// reinit-expected(unex, val, rhs.error())
// E move is not noexcept
// In this case, it should call the branch
//
// U tmp(std::move(oldval));
// destroy_at(addressof(oldval));
// try {
// construct_at(addressof(newval), std::forward<Args>(args)...);
// } catch (...) {
// construct_at(addressof(oldval), std::move(tmp));
// throw;
// }
//
{
TracedNoexcept::state oldState{};
Traced::state newState{};
std::expected<TracedNoexcept, Traced> e1(std::in_place, oldState, 5);
const std::expected<TracedNoexcept, Traced> e2(std::unexpect, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<TracedNoexcept, Traced>&>);
assert(&x == &e1);
assert(!e1.has_value());
assert(e1.error().data_ == 10);
assert(!oldState.copyAssignCalled);
assert(oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!oldState.copyCtorCalled);
assert(newState.copyCtorCalled);
assert(!newState.moveCtorCalled);
assert(!newState.dtorCalled);
}
// - Otherwise, if this->has_value() is true, equivalent to:
// reinit-expected(unex, val, rhs.error())
// E move is noexcept
// In this case, it should call the branch
//
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::forward<Args>(args)...);
//
{
Traced::state oldState{};
TracedNoexcept::state newState{};
std::expected<Traced, TracedNoexcept> e1(std::in_place, oldState, 5);
const std::expected<Traced, TracedNoexcept> e2(std::unexpect, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<Traced, TracedNoexcept>&>);
assert(&x == &e1);
assert(!e1.has_value());
assert(e1.error().data_ == 10);
assert(!oldState.copyAssignCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!oldState.copyCtorCalled);
assert(newState.copyCtorCalled);
assert(!newState.moveCtorCalled);
assert(!newState.dtorCalled);
}
// - Otherwise, if rhs.has_value() is true, equivalent to:
// reinit-expected(val, unex, *rhs)
// T move is not noexcept
// In this case, it should call the branch
//
// U tmp(std::move(oldval));
// destroy_at(addressof(oldval));
// try {
// construct_at(addressof(newval), std::forward<Args>(args)...);
// } catch (...) {
// construct_at(addressof(oldval), std::move(tmp));
// throw;
// }
//
{
TracedNoexcept::state oldState{};
Traced::state newState{};
std::expected<Traced, TracedNoexcept> e1(std::unexpect, oldState, 5);
const std::expected<Traced, TracedNoexcept> e2(std::in_place, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<Traced, TracedNoexcept>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyAssignCalled);
assert(oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!oldState.copyCtorCalled);
assert(newState.copyCtorCalled);
assert(!newState.moveCtorCalled);
assert(!newState.dtorCalled);
}
// - Otherwise, if rhs.has_value() is true, equivalent to:
// reinit-expected(val, unex, *rhs)
// T move is noexcept
// In this case, it should call the branch
//
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::forward<Args>(args)...);
//
{
Traced::state oldState{};
TracedNoexcept::state newState{};
std::expected<TracedNoexcept, Traced> e1(std::unexpect, oldState, 5);
const std::expected<TracedNoexcept, Traced> e2(std::in_place, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<TracedNoexcept, Traced>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyAssignCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!oldState.copyCtorCalled);
assert(newState.copyCtorCalled);
assert(!newState.moveCtorCalled);
assert(!newState.dtorCalled);
}
// Otherwise, equivalent to unex = rhs.error().
{
Traced::state oldState{};
Traced::state newState{};
std::expected<int, Traced> e1(std::unexpect, oldState, 5);
const std::expected<int, Traced> e2(std::unexpect, newState, 10);
decltype(auto) x = (e1 = e2);
static_assert(std::same_as<decltype(x), std::expected<int, Traced>&>);
assert(&x == &e1);
assert(!e1.has_value());
assert(e1.error().data_ == 10);
assert(oldState.copyAssignCalled);
}
// CheckForInvalidWrites
{
{
CheckForInvalidWrites<true> e1(std::unexpect);
CheckForInvalidWrites<true> e2;
e1 = e2;
assert(e1.check());
assert(e2.check());
}
{
CheckForInvalidWrites<false> e1(std::unexpect);
CheckForInvalidWrites<false> e2;
e1 = e2;
assert(e1.check());
assert(e2.check());
}
}
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
struct ThrowOnCopyMoveMayThrow {
ThrowOnCopyMoveMayThrow() = default;
ThrowOnCopyMoveMayThrow(const ThrowOnCopyMoveMayThrow&) { throw Except{}; };
ThrowOnCopyMoveMayThrow& operator=(const ThrowOnCopyMoveMayThrow&) = default;
ThrowOnCopyMoveMayThrow(ThrowOnCopyMoveMayThrow&&) noexcept(false) {}
};
// assign value throw on copy
{
std::expected<ThrowOnCopyMoveMayThrow, int> e1(std::unexpect, 5);
const std::expected<ThrowOnCopyMoveMayThrow, int> e2(std::in_place);
try {
e1 = e2;
assert(false);
} catch (Except) {
assert(!e1.has_value());
assert(e1.error() == 5);
}
}
// assign error throw on copy
{
std::expected<int, ThrowOnCopyMoveMayThrow> e1(5);
const std::expected<int, ThrowOnCopyMoveMayThrow> e2(std::unexpect);
try {
e1 = e2;
assert(false);
} catch (Except) {
assert(e1.has_value());
assert(e1.value() == 5);
}
}
#endif // TEST_HAS_NO_EXCEPTIONS
}
int main(int, char**) {
test();
static_assert(test());
testException();
return 0;
}
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