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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... Args>
// constexpr T& emplace(Args&&... args) noexcept;
// Constraints: is_nothrow_constructible_v<T, Args...> is true.
//
// Effects: Equivalent to:
// if (has_value()) {
// destroy_at(addressof(val));
// } else {
// destroy_at(addressof(unex));
// has_val = true;
// }
// return *construct_at(addressof(val), std::forward<Args>(args)...);
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "../../types.h"
#include "test_macros.h"
template <class T, class... Args>
concept CanEmplace = requires(T t, Args&&... args) { t.emplace(std::forward<Args>(args)...); };
static_assert(CanEmplace<std::expected<int, int>, int>);
template <bool Noexcept>
struct CtorFromInt {
CtorFromInt(int) noexcept(Noexcept);
CtorFromInt(int, int) noexcept(Noexcept);
};
static_assert(CanEmplace<std::expected<CtorFromInt<true>, int>, int>);
static_assert(CanEmplace<std::expected<CtorFromInt<true>, int>, int, int>);
static_assert(!CanEmplace<std::expected<CtorFromInt<false>, int>, int>);
static_assert(!CanEmplace<std::expected<CtorFromInt<false>, int>, int, int>);
constexpr bool test() {
// has_value
{
BothNoexcept::state oldState{};
BothNoexcept::state newState{};
std::expected<BothNoexcept, int> e(std::in_place, oldState, 5);
decltype(auto) x = e.emplace(newState, 10);
static_assert(std::same_as<decltype(x), BothNoexcept&>);
assert(&x == &(*e));
assert(oldState.dtorCalled);
assert(e.has_value());
assert(e.value().data_ == 10);
}
// !has_value
{
BothMayThrow::state oldState{};
std::expected<int, BothMayThrow> e(std::unexpect, oldState, 5);
decltype(auto) x = e.emplace(10);
static_assert(std::same_as<decltype(x), int&>);
assert(&x == &(*e));
assert(oldState.dtorCalled);
assert(e.has_value());
assert(e.value() == 10);
}
// TailClobberer
{
std::expected<TailClobberer<0>, bool> e(std::unexpect);
e.emplace();
assert(e.has_value());
}
// CheckForInvalidWrites
{
{
CheckForInvalidWrites<true> e;
e.emplace();
assert(e.check());
}
{
CheckForInvalidWrites<false> e;
e.emplace();
assert(e.check());
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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