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-has-no-incomplete-ranges
11 
12 // std::ranges::borrowed_subrange_t;
13 
14 #include <ranges>
15 
16 #include <concepts>
17 #include <span>
18 #include <string>
19 #include <string_view>
20 #include <vector>
21 
22 static_assert(std::same_as<std::ranges::borrowed_subrange_t<std::string>, std::ranges::dangling>);
23 static_assert(std::same_as<std::ranges::borrowed_subrange_t<std::string&&>, std::ranges::dangling>);
24 static_assert(std::same_as<std::ranges::borrowed_subrange_t<std::vector<int> >, std::ranges::dangling>);
25 
26 static_assert(
27     std::same_as<std::ranges::borrowed_subrange_t<std::string&>, std::ranges::subrange<std::string::iterator> >);
28 
29 static_assert(
30     std::same_as<std::ranges::borrowed_subrange_t<std::span<int> >, std::ranges::subrange<std::span<int>::iterator> >);
31 
32 static_assert(std::same_as<std::ranges::borrowed_subrange_t<std::string_view>,
33                            std::ranges::subrange<std::string_view::iterator> >);
34 
35 template <class T>
36 constexpr bool has_type = requires {
37   typename std::ranges::borrowed_subrange_t<T>;
38 };
39 
40 static_assert(!has_type<int>);
41 
42 struct S {};
43 static_assert(!has_type<S>);
44