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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
// constexpr decltype(auto) operator[](iter_difference_t<I> n) const
// requires random_access_iterator<I>;
#include <iterator>
#include "test_macros.h"
#include "test_iterators.h"
template<class Iter>
concept SubscriptEnabled = requires(Iter& iter) {
iter[1];
};
constexpr bool test() {
int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
{
std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
for (int i = 1; i < 9; ++i)
assert(iter[i - 1] == i);
}
{
std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
for (int i = 1; i < 9; ++i)
assert(iter[i - 1] == i);
}
{
const std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
assert(iter[0] == 1);
}
{
const std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
assert(iter[7] == 8);
}
{
static_assert( SubscriptEnabled<std::counted_iterator<random_access_iterator<int*>>>);
static_assert(!SubscriptEnabled<std::counted_iterator<bidirectional_iterator<int*>>>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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