1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: c++03, c++11, c++14, c++17
10 // UNSUPPORTED: libcpp-no-concepts
11 // UNSUPPORTED: gcc-10
12 
13 // ranges::next
14 // Make sure we're SFINAE-friendly when the template argument constraints are not met.
15 
16 #include <iterator>
17 
18 #include <cstddef>
19 #include <memory>
20 #include <utility>
21 #include "test_iterators.h"
22 
23 template <class ...Args>
24 concept has_ranges_next = requires (Args&& ...args) {
25   { std::ranges::next(std::forward<Args>(args)...) };
26 };
27 
28 using It = std::unique_ptr<int>;
29 static_assert(!has_ranges_next<It>);
30 static_assert(!has_ranges_next<It, std::ptrdiff_t>);
31 static_assert(!has_ranges_next<It, It>);
32 static_assert(!has_ranges_next<It, std::ptrdiff_t, It>);
33 
34 // Test the test
35 using It2 = forward_iterator<int*>;
36 static_assert(has_ranges_next<It2>);
37 static_assert(has_ranges_next<It2, std::ptrdiff_t>);
38 static_assert(has_ranges_next<It2, std::ptrdiff_t, It2>);
39