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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
// GCC has a issue for `Guaranteed copy elision for potentially-overlapping non-static data members`,
// please refer to: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108333
// XFAIL: gcc-13
// <expected>
// template<class F> constexpr auto transform_error(F&& f) &;
// template<class F> constexpr auto transform_error(F&& f) const &;
// template<class F> constexpr auto transform_error(F&& f) &&;
// template<class F> constexpr auto transform_error(F&& f) const &&;
#include <expected>
#include <concepts>
#include <cassert>
#include <type_traits>
#include <utility>
struct NonCopy {
int value;
constexpr explicit NonCopy(int val) : value(val) {}
NonCopy(const NonCopy&) = delete;
};
constexpr void test_val_types() {
// Test & overload
{
auto l = [](auto) -> int { return 1; };
std::expected<void, int> v(std::unexpected<int>(2));
std::same_as<std::expected<void, int>> decltype(auto) val = v.transform_error(l);
assert(val.error() == 1);
}
// Test const& overload
{
auto l = [](auto) -> int { return 1; };
const std::expected<void, int> v(std::unexpected<int>(2));
std::same_as<std::expected<void, int>> decltype(auto) val = v.transform_error(l);
assert(val.error() == 1);
}
// Test && overload
{
auto l = [](auto) -> int { return 1; };
std::expected<void, int> v(std::unexpected<int>(2));
std::same_as<std::expected<void, int>> decltype(auto) val = std::move(v).transform_error(l);
assert(val.error() == 1);
}
// Test const&& overload
{
auto l = [](auto) -> int { return 1; };
const std::expected<void, int> v(std::unexpected<int>(2));
std::same_as<std::expected<void, int>> decltype(auto) val = std::move(v).transform_error(l);
assert(val.error() == 1);
}
}
constexpr void test_fail() {
// Test & overload
{
auto l = [](auto) -> int {
assert(false);
return 0;
};
std::expected<void, int> v;
std::same_as<std::expected<void, int>> decltype(auto) val = v.transform_error(l);
assert(val.has_value());
}
// Test const& overload
{
auto l = [](auto) -> int {
assert(false);
return 0;
};
const std::expected<void, int> v;
std::same_as<std::expected<void, int>> decltype(auto) val = v.transform_error(l);
assert(val.has_value());
}
// Test && overload
{
auto l = [](auto) -> int {
assert(false);
return 0;
};
std::expected<void, int> v;
std::same_as<std::expected<void, int>> decltype(auto) val = std::move(v).transform_error(l);
assert(val.has_value());
}
// Test const&& overload
{
auto l = [](auto) -> int {
assert(false);
return 0;
};
const std::expected<void, int> v;
std::same_as<std::expected<void, int>> decltype(auto) val = std::move(v).transform_error(l);
assert(val.has_value());
}
}
// check unex member is direct-non-list-initialized with invoke(std::forward<F>(f))
constexpr void test_direct_non_list_init() {
auto x = [](int i) { return NonCopy(i); };
std::expected<void, int> v(std::unexpected<int>(2));
std::expected<void, NonCopy> nv = v.transform_error(x);
assert(nv.error().value == 2);
}
constexpr bool test() {
test_fail();
test_val_types();
test_direct_non_list_init();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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