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 R>
14 //   explicit join_view(R&&) -> join_view<views::all_t<R>>;
15 
16 #include <ranges>
17 
18 #include "test_iterators.h"
19 
20 template<class T>
21 struct View : std::ranges::view_base {
22   // All friends here are defined to prevent GCC warnings.
23   friend T* begin(View&) { return nullptr; }
24   friend T* begin(View const&) { return nullptr; }
25   friend sentinel_wrapper<T*> end(View&) { return sentinel_wrapper<T*>(nullptr); }
26   friend sentinel_wrapper<T*> end(View const&) { return sentinel_wrapper<T*>(nullptr); }
27 };
28 
29 template<class T>
30 struct Range {
31   friend T* begin(Range&) { return nullptr; }
32   friend T* begin(Range const&) { return nullptr; }
33   friend sentinel_wrapper<T*> end(Range&) { return sentinel_wrapper<T*>(nullptr); }
34   friend sentinel_wrapper<T*> end(Range const&) { return sentinel_wrapper<T*>(nullptr); }
35 };
36 
37 template<class T>
38 struct BorrowedRange {
39   friend T* begin(BorrowedRange&) { return nullptr; }
40   friend T* begin(BorrowedRange const&) { return nullptr; }
41   friend sentinel_wrapper<T*> end(BorrowedRange&) { return sentinel_wrapper<T*>(nullptr); }
42   friend sentinel_wrapper<T*> end(BorrowedRange const&) { return sentinel_wrapper<T*>(nullptr); }
43 };
44 
45 template<>
46 inline constexpr bool std::ranges::enable_borrowed_range<BorrowedRange<BorrowedRange<int>>> = true;
47 
48 void testCTAD() {
49     View<View<int>> v;
50     Range<Range<int>> r;
51     BorrowedRange<BorrowedRange<int>> br;
52 
53     static_assert(std::same_as<
54         decltype(std::ranges::join_view(v)),
55         std::ranges::join_view<View<View<int>>>
56     >);
57     static_assert(std::same_as<
58         decltype(std::ranges::join_view(r)),
59         std::ranges::join_view<std::ranges::ref_view<Range<Range<int>>>>
60     >);
61     // std::ranges::join_view(std::move(r)) invalid. RValue range must be borrowed.
62     static_assert(std::same_as<
63         decltype(std::ranges::join_view(br)),
64         std::ranges::join_view<std::ranges::ref_view<BorrowedRange<BorrowedRange<int>>>>
65     >);
66     static_assert(std::same_as<
67         decltype(std::ranges::join_view(std::move(br))),
68         std::ranges::join_view<std::ranges::subrange<BorrowedRange<int> *,
69                                sentinel_wrapper<BorrowedRange<int> *>,
70                                std::ranges::subrange_kind::unsized>>
71     >);
72 }
73