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: libcpp-has-no-incomplete-ranges
12 
13 // template<class T>
14 //   inline constexpr bool enable_borrowed_range<common_view<T>> = enable_borrowed_range<T>;
15 
16 #include <ranges>
17 
18 // common_view can only wrap Ts that are `view<T> && !common_range<T>`, so we need to invent one.
19 struct Uncommon : std::ranges::view_base {
20     int *begin() const;
21     std::unreachable_sentinel_t end() const;
22 };
23 
24 static_assert(!std::ranges::borrowed_range<std::ranges::common_view<Uncommon>>);
25 static_assert(!std::ranges::borrowed_range<std::ranges::common_view<std::ranges::owning_view<Uncommon>>>);
26 static_assert( std::ranges::borrowed_range<std::ranges::common_view<std::ranges::ref_view<Uncommon>>>);
27