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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
// <optional>
// template<class F> constexpr auto and_then(F&&) &;
// template<class F> constexpr auto and_then(F&&) &&;
// template<class F> constexpr auto and_then(F&&) const&;
// template<class F> constexpr auto and_then(F&&) const&&;
#include <cassert>
#include <optional>
#include "test_macros.h"
struct LVal {
constexpr std::optional<int> operator()(int&) { return 1; }
std::optional<int> operator()(const int&) = delete;
std::optional<int> operator()(int&&) = delete;
std::optional<int> operator()(const int&&) = delete;
};
struct CLVal {
std::optional<int> operator()(int&) = delete;
constexpr std::optional<int> operator()(const int&) { return 1; }
std::optional<int> operator()(int&&) = delete;
std::optional<int> operator()(const int&&) = delete;
};
struct RVal {
std::optional<int> operator()(int&) = delete;
std::optional<int> operator()(const int&) = delete;
constexpr std::optional<int> operator()(int&&) { return 1; }
std::optional<int> operator()(const int&&) = delete;
};
struct CRVal {
std::optional<int> operator()(int&) = delete;
std::optional<int> operator()(const int&) = delete;
std::optional<int> operator()(int&&) = delete;
constexpr std::optional<int> operator()(const int&&) { return 1; }
};
struct RefQual {
constexpr std::optional<int> operator()(int) & { return 1; }
std::optional<int> operator()(int) const& = delete;
std::optional<int> operator()(int) && = delete;
std::optional<int> operator()(int) const&& = delete;
};
struct CRefQual {
std::optional<int> operator()(int) & = delete;
constexpr std::optional<int> operator()(int) const& { return 1; }
std::optional<int> operator()(int) && = delete;
std::optional<int> operator()(int) const&& = delete;
};
struct RVRefQual {
std::optional<int> operator()(int) & = delete;
std::optional<int> operator()(int) const& = delete;
constexpr std::optional<int> operator()(int) && { return 1; }
std::optional<int> operator()(int) const&& = delete;
};
struct RVCRefQual {
std::optional<int> operator()(int) & = delete;
std::optional<int> operator()(int) const& = delete;
std::optional<int> operator()(int) && = delete;
constexpr std::optional<int> operator()(int) const&& { return 1; }
};
struct NOLVal {
constexpr std::optional<int> operator()(int&) { return std::nullopt; }
std::optional<int> operator()(const int&) = delete;
std::optional<int> operator()(int&&) = delete;
std::optional<int> operator()(const int&&) = delete;
};
struct NOCLVal {
std::optional<int> operator()(int&) = delete;
constexpr std::optional<int> operator()(const int&) { return std::nullopt; }
std::optional<int> operator()(int&&) = delete;
std::optional<int> operator()(const int&&) = delete;
};
struct NORVal {
std::optional<int> operator()(int&) = delete;
std::optional<int> operator()(const int&) = delete;
constexpr std::optional<int> operator()(int&&) { return std::nullopt; }
std::optional<int> operator()(const int&&) = delete;
};
struct NOCRVal {
std::optional<int> operator()(int&) = delete;
std::optional<int> operator()(const int&) = delete;
std::optional<int> operator()(int&&) = delete;
constexpr std::optional<int> operator()(const int&&) { return std::nullopt; }
};
struct NORefQual {
constexpr std::optional<int> operator()(int) & { return std::nullopt; }
std::optional<int> operator()(int) const& = delete;
std::optional<int> operator()(int) && = delete;
std::optional<int> operator()(int) const&& = delete;
};
struct NOCRefQual {
std::optional<int> operator()(int) & = delete;
constexpr std::optional<int> operator()(int) const& { return std::nullopt; }
std::optional<int> operator()(int) && = delete;
std::optional<int> operator()(int) const&& = delete;
};
struct NORVRefQual {
std::optional<int> operator()(int) & = delete;
std::optional<int> operator()(int) const& = delete;
constexpr std::optional<int> operator()(int) && { return std::nullopt; }
std::optional<int> operator()(int) const&& = delete;
};
struct NORVCRefQual {
std::optional<int> operator()(int) & = delete;
std::optional<int> operator()(int) const& = delete;
std::optional<int> operator()(int) && = delete;
constexpr std::optional<int> operator()(int) const&& { return std::nullopt; }
};
struct NoCopy {
NoCopy() = default;
NoCopy(const NoCopy&) { assert(false); }
std::optional<int> operator()(const NoCopy&&) { return 1; }
};
struct NonConst {
std::optional<int> non_const() { return 1; }
};
constexpr void test_val_types() {
// Test & overload
{
// Without & qualifier on F's operator()
{
std::optional<int> i{0};
assert(i.and_then(LVal{}) == 1);
assert(i.and_then(NOLVal{}) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(LVal{})), std::optional<int>);
}
//With & qualifier on F's operator()
{
std::optional<int> i{0};
RefQual l{};
assert(i.and_then(l) == 1);
NORefQual nl{};
assert(i.and_then(nl) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(l)), std::optional<int>);
}
}
// Test const& overload
{
// Without & qualifier on F's operator()
{
const std::optional<int> i{0};
assert(i.and_then(CLVal{}) == 1);
assert(i.and_then(NOCLVal{}) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(CLVal{})), std::optional<int>);
}
//With & qualifier on F's operator()
{
const std::optional<int> i{0};
const CRefQual l{};
assert(i.and_then(l) == 1);
const NOCRefQual nl{};
assert(i.and_then(nl) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(l)), std::optional<int>);
}
}
// Test && overload
{
// Without & qualifier on F's operator()
{
std::optional<int> i{0};
assert(std::move(i).and_then(RVal{}) == 1);
assert(std::move(i).and_then(NORVal{}) == std::nullopt);
ASSERT_SAME_TYPE(decltype(std::move(i).and_then(RVal{})), std::optional<int>);
}
//With & qualifier on F's operator()
{
std::optional<int> i{0};
assert(i.and_then(RVRefQual{}) == 1);
assert(i.and_then(NORVRefQual{}) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(RVRefQual{})), std::optional<int>);
}
}
// Test const&& overload
{
// Without & qualifier on F's operator()
{
const std::optional<int> i{0};
assert(std::move(i).and_then(CRVal{}) == 1);
assert(std::move(i).and_then(NOCRVal{}) == std::nullopt);
ASSERT_SAME_TYPE(decltype(std::move(i).and_then(CRVal{})), std::optional<int>);
}
//With & qualifier on F's operator()
{
const std::optional<int> i{0};
const RVCRefQual l{};
assert(i.and_then(std::move(l)) == 1);
const NORVCRefQual nl{};
assert(i.and_then(std::move(nl)) == std::nullopt);
ASSERT_SAME_TYPE(decltype(i.and_then(std::move(l))), std::optional<int>);
}
}
}
// check that the lambda body is not instantiated during overload resolution
constexpr void test_sfinae() {
std::optional<NonConst> opt{};
auto l = [](auto&& x) { return x.non_const(); };
opt.and_then(l);
std::move(opt).and_then(l);
}
constexpr bool test() {
test_val_types();
std::optional<int> opt{};
const auto& copt = opt;
const auto never_called = [](int) {
assert(false);
return std::optional<int>{};
};
opt.and_then(never_called);
std::move(opt).and_then(never_called);
copt.and_then(never_called);
std::move(copt).and_then(never_called);
std::optional<NoCopy> nc;
const auto& cnc = nc;
std::move(cnc).and_then(NoCopy{});
std::move(nc).and_then(NoCopy{});
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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