| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // UNSUPPORTED: libcpp-no-concepts |
| // UNSUPPORTED: gcc-10 |
| |
| // 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; |
| } |