89c8a253d7
We haven't yet decided what we want the `optional::iterator` type to be in the end, so let's make it experimental for now so that we don't commit to an ABI yet.
72 lines
2.0 KiB
C++
72 lines
2.0 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// REQUIRES: std-at-least-c++26
|
|
|
|
// UNSUPPORTED: libcpp-has-no-experimental-optional-iterator
|
|
|
|
// <optional>
|
|
|
|
// constexpr iterator optional::begin() noexcept;
|
|
// constexpr const_iterator optional::begin() const noexcept;
|
|
|
|
#include <cassert>
|
|
#include <iterator>
|
|
#include <optional>
|
|
#include <type_traits>
|
|
#include <utility>
|
|
|
|
template <typename T>
|
|
constexpr bool test() {
|
|
std::remove_reference_t<T> t = std::remove_reference_t<T>{};
|
|
std::optional<T> opt{t};
|
|
|
|
{ // begin() is marked noexcept
|
|
static_assert(noexcept(opt.begin()));
|
|
static_assert(noexcept(std::as_const(opt).begin()));
|
|
}
|
|
|
|
{ // Dereferencing an iterator at the beginning == indexing the 0th element, and that calling begin() again return the same iterator.
|
|
auto iter1 = opt.begin();
|
|
auto iter2 = std::as_const(opt).begin();
|
|
assert(*iter1 == iter1[0]);
|
|
assert(*iter2 == iter2[0]);
|
|
assert(iter1 == opt.begin());
|
|
assert(iter2 == std::as_const(opt).begin());
|
|
}
|
|
|
|
{ // Calling begin() multiple times on a disengaged optional returns the same iterator.
|
|
std::optional<T> disengaged{std::nullopt};
|
|
auto iter1 = disengaged.begin();
|
|
auto iter2 = std::as_const(disengaged).begin();
|
|
assert(iter1 == disengaged.begin());
|
|
assert(iter2 == std::as_const(disengaged).begin());
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
constexpr bool tests() {
|
|
assert(test<int>());
|
|
assert(test<char>());
|
|
assert(test<const int>());
|
|
assert(test<const char>());
|
|
assert(test<int&>());
|
|
assert(test<char&>());
|
|
assert(test<const int&>());
|
|
assert(test<const char&>());
|
|
return true;
|
|
}
|
|
|
|
int main(int, char**) {
|
|
assert(tests());
|
|
static_assert(tests());
|
|
|
|
return 0;
|
|
}
|