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, c++20
10
11 // <ranges>
12
13 // constexpr Pred const& pred() const;
14
15 #include <ranges>
16
17 #include <cassert>
18 #include <concepts>
19
20 struct Range : std::ranges::view_base {
21 int* begin() const;
22 int* end() const;
23 };
24
25 struct Pred {
26 bool operator()(int, int) const;
27 int value;
28 };
29
test()30 constexpr bool test() {
31 {
32 Pred pred{42};
33 std::ranges::chunk_by_view<Range, Pred> const view(Range{}, pred);
34 std::same_as<Pred const&> decltype(auto) result = view.pred();
35 assert(result.value == 42);
36
37 // Make sure we're really holding a reference to something inside the view
38 assert(&result == &view.pred());
39 }
40
41 // Same, but calling on a non-const view
42 {
43 Pred pred{42};
44 std::ranges::chunk_by_view<Range, Pred> view(Range{}, pred);
45 std::same_as<Pred const&> decltype(auto) result = view.pred();
46 assert(result.value == 42);
47
48 // Make sure we're really holding a reference to something inside the view
49 assert(&result == &view.pred());
50 }
51
52 return true;
53 }
54
main(int,char **)55 int main(int, char**) {
56 test();
57 static_assert(test());
58
59 return 0;
60 }
61