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 // template<class T>
13 //   inline constexpr bool enable_borrowed_range<common_view<T>> = enable_borrowed_range<T>;
14 
15 #include <ranges>
16 
17 // common_view can only wrap Ts that are `view<T> && !common_range<T>`, so we need to invent one.
18 struct Uncommon : std::ranges::view_base {
19     int *begin() const;
20     std::unreachable_sentinel_t end() const;
21 };
22 
23 static_assert(!std::ranges::borrowed_range<std::ranges::common_view<Uncommon>>);
24 static_assert(!std::ranges::borrowed_range<std::ranges::common_view<std::ranges::owning_view<Uncommon>>>);
25 static_assert( std::ranges::borrowed_range<std::ranges::common_view<std::ranges::ref_view<Uncommon>>>);
26