//===----------------------------------------------------------------------===//
//
// 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 = T>
// constexpr expected& operator=(U&& v);
//
// Constraints:
// - is_same_v<expected, remove_cvref_t<U>> is false; and
// - remove_cvref_t<U> is not a specialization of unexpected; and
// - is_constructible_v<T, U> is true; and
// - is_assignable_v<T&, U> is true; and
// - is_nothrow_constructible_v<T, U> || is_nothrow_move_constructible_v<T> ||
// is_nothrow_move_constructible_v<E> is true.
//
// Effects:
// - If has_value() is true, equivalent to: val = std::forward<U>(v);
// - Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// has_val = true;
// - Returns: *this.
#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;
};
// Test constraints
static_assert(std::is_assignable_v<std::expected<int, int>&, int>);
// is_same_v<expected, remove_cvref_t<U>>
// it is true because it covered by the copy assignment
static_assert(std::is_assignable_v<std::expected<int, int>&, std::expected<int, int>>);
// remove_cvref_t<U> is a specialization of unexpected
// it is true because it covered the unexpected overload
static_assert(std::is_assignable_v<std::expected<int, int>&, std::unexpected<int>>);
// !is_constructible_v<T, U>
struct NoCtorFromInt {
NoCtorFromInt(int) = delete;
NoCtorFromInt& operator=(int);
};
static_assert(!std::is_assignable_v<std::expected<NoCtorFromInt, int>&, int>);
// !is_assignable_v<T&, U>
struct NoAssignFromInt {
explicit NoAssignFromInt(int);
NoAssignFromInt& operator=(int) = delete;
};
static_assert(!std::is_assignable_v<std::expected<NoAssignFromInt, int>&, int>);
template <bool moveNoexcept, bool convertNoexcept>
struct MaybeNoexcept {
explicit MaybeNoexcept(int) noexcept(convertNoexcept);
MaybeNoexcept(MaybeNoexcept&&) noexcept(moveNoexcept);
MaybeNoexcept& operator=(MaybeNoexcept&&) = default;
MaybeNoexcept& operator=(int);
};
// !is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// is_nothrow_move_constructible_v<E>
static_assert(std::is_assignable_v<std::expected<MaybeNoexcept<false, false>, int>&, int>);
// is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
static_assert(std::is_assignable_v<std::expected<MaybeNoexcept<false, true>, MaybeNoexcept<false, false>>&, int>);
// !is_nothrow_constructible_v<T, U> && is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
static_assert(std::is_assignable_v<std::expected<MaybeNoexcept<true, false>, MaybeNoexcept<false, false>>&, int>);
// !is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
static_assert(!std::is_assignable_v<std::expected<MaybeNoexcept<false, false>, MaybeNoexcept<false, false>>&, int>);
constexpr bool test() {
// If has_value() is true, equivalent to: val = std::forward<U>(v);
// Copy
{
Traced::state oldState{};
Traced::state newState{};
std::expected<Traced, int> e1(std::in_place, oldState, 5);
Traced u(newState, 10);
decltype(auto) x = (e1 = u);
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);
}
// If has_value() is true, equivalent to: val = std::forward<U>(v);
// Move
{
Traced::state oldState{};
Traced::state newState{};
std::expected<Traced, int> e1(std::in_place, oldState, 5);
Traced u(newState, 10);
decltype(auto) x = (e1 = std::move(u));
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.moveAssignCalled);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
// copy
//
// In this case, it should call the branch
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::forward<Args>(args)...);
{
BothMayThrow::state oldState{};
std::expected<MoveThrowConvNoexcept, BothMayThrow> e1(std::unexpect, oldState, 5);
const int i = 10;
decltype(auto) x = (e1 = i);
static_assert(std::same_as<decltype(x), std::expected<MoveThrowConvNoexcept, BothMayThrow>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(e1.value().copiedFromInt);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
// move
//
// In this case, it should call the branch
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::forward<Args>(args)...);
{
BothMayThrow::state oldState{};
std::expected<MoveThrowConvNoexcept, BothMayThrow> e1(std::unexpect, oldState, 5);
decltype(auto) x = (e1 = 10);
static_assert(std::same_as<decltype(x), std::expected<MoveThrowConvNoexcept, BothMayThrow>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(e1.value().movedFromInt);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// !is_nothrow_constructible_v<T, U> && is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
// copy
//
// In this case, it should call the branch
// T tmp(std::forward<Args>(args)...);
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::move(tmp));
{
BothMayThrow::state oldState{};
std::expected<MoveNoexceptConvThrow, BothMayThrow> e1(std::unexpect, oldState, 5);
const int i = 10;
decltype(auto) x = (e1 = i);
static_assert(std::same_as<decltype(x), std::expected<MoveNoexceptConvThrow, BothMayThrow>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!e1.value().copiedFromInt);
assert(e1.value().movedFromTmp);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// !is_nothrow_constructible_v<T, U> && is_nothrow_move_constructible_v<T> &&
// !is_nothrow_move_constructible_v<E>
// move
//
// In this case, it should call the branch
// T tmp(std::forward<Args>(args)...);
// destroy_at(addressof(oldval));
// construct_at(addressof(newval), std::move(tmp));
{
BothMayThrow::state oldState{};
std::expected<MoveNoexceptConvThrow, BothMayThrow> e1(std::unexpect, oldState, 5);
decltype(auto) x = (e1 = 10);
static_assert(std::same_as<decltype(x), std::expected<MoveNoexceptConvThrow, BothMayThrow>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(!oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(!e1.value().copiedFromInt);
assert(e1.value().movedFromTmp);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// !is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// is_nothrow_move_constructible_v<E>
// copy
//
// 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{};
std::expected<BothMayThrow, TracedNoexcept> e1(std::unexpect, oldState, 5);
const int i = 10;
decltype(auto) x = (e1 = i);
static_assert(std::same_as<decltype(x), std::expected<BothMayThrow, TracedNoexcept>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(e1.value().copiedFromInt);
}
// Otherwise, equivalent to:
// reinit-expected(val, unex, std::forward<U>(v));
// !is_nothrow_constructible_v<T, U> && !is_nothrow_move_constructible_v<T> &&
// is_nothrow_move_constructible_v<E>
// move
//
// 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{};
std::expected<BothMayThrow, TracedNoexcept> e1(std::unexpect, oldState, 5);
decltype(auto) x = (e1 = 10);
static_assert(std::same_as<decltype(x), std::expected<BothMayThrow, TracedNoexcept>&>);
assert(&x == &e1);
assert(e1.has_value());
assert(e1.value().data_ == 10);
assert(!oldState.copyCtorCalled);
assert(oldState.moveCtorCalled);
assert(oldState.dtorCalled);
assert(e1.value().movedFromInt);
}
// Test default template argument.
// Without it, the template parameter cannot be deduced from an initializer list
{
struct Bar {
int i;
int j;
constexpr Bar(int ii, int jj) : i(ii), j(jj) {}
};
std::expected<Bar, int> e({5, 6});
e = {7, 8};
assert(e.value().i == 7);
assert(e.value().j == 8);
}
// CheckForInvalidWrites
{
{
CheckForInvalidWrites<true> e1(std::unexpect);
e1 = 42;
assert(e1.check());
}
{
CheckForInvalidWrites<false> e1(std::unexpect);
e1 = true;
assert(e1.check());
}
}
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
std::expected<ThrowOnConvert, int> e1(std::unexpect, 5);
try {
e1 = 10;
assert(false);
} catch (Except) {
assert(!e1.has_value());
assert(e1.error() == 5);
}
#endif // TEST_HAS_NO_EXCEPTIONS
}
int main(int, char**) {
test();
static_assert(test());
testException();
return 0;
}
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