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 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
13 
14 // template<class R>
15 //   take_view(R&&, range_difference_t<R>) -> take_view<views::all_t<R>>;
16 
17 #include <ranges>
18 #include <cassert>
19 #include <concepts>
20 
21 #include "test_iterators.h"
22 
23 struct View : std::ranges::view_base {
24   friend int* begin(View&);
25   friend int* begin(View const&);
26   friend sentinel_wrapper<int*> end(View&);
27   friend sentinel_wrapper<int*> end(View const&);
28 };
29 
30 struct Range {
31   friend int* begin(Range&);
32   friend int* begin(Range const&);
33   friend sentinel_wrapper<int*> end(Range&);
34   friend sentinel_wrapper<int*> end(Range const&);
35 };
36 
37 struct BorrowedRange {
38   friend int* begin(BorrowedRange&);
39   friend int* begin(BorrowedRange const&);
40   friend sentinel_wrapper<int*> end(BorrowedRange&);
41   friend sentinel_wrapper<int*> end(BorrowedRange const&);
42 };
43 
44 template<>
45 inline constexpr bool std::ranges::enable_borrowed_range<BorrowedRange> = true;
46 
47 void testCTAD() {
48     View v;
49     Range r;
50     BorrowedRange br;
51     static_assert(std::same_as<
52         decltype(std::ranges::take_view(v, 0)),
53         std::ranges::take_view<View>
54     >);
55     static_assert(std::same_as<
56         decltype(std::ranges::take_view(r, 0)),
57         std::ranges::take_view<std::ranges::ref_view<Range>>
58     >);
59     // std::ranges::take_view(std::move(r), 0) invalid. RValue range must be borrowed.
60     static_assert(std::same_as<
61         decltype(std::ranges::take_view(br, 0)),
62         std::ranges::take_view<std::ranges::ref_view<BorrowedRange>>
63     >);
64     static_assert(std::same_as<
65         decltype(std::ranges::take_view(std::move(br), 0)),
66         std::ranges::take_view<std::ranges::subrange<
67           int *, sentinel_wrapper<int *>, std::ranges::subrange_kind::unsized>>
68     >);
69 }
70