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 // constexpr iterator<false> begin();
13 // constexpr iterator<true> begin() const
14 //   requires range<const V> &&
15 //            regular_invocable<const F&, range_reference_t<const V>>;
16 
17 #include <ranges>
18 
19 #include "test_macros.h"
20 #include "types.h"
21 
22 template<class T>
23 concept BeginInvocable = requires(T t) { t.begin(); };
24 
25 constexpr bool test() {
26   int buff[8] = {0, 1, 2, 3, 4, 5, 6, 7};
27 
28   {
29     std::ranges::transform_view transformView(MoveOnlyView{buff}, PlusOneMutable{});
30     assert(transformView.begin().base() == buff);
31     assert(*transformView.begin() == 1);
32   }
33 
34   {
35     std::ranges::transform_view transformView(ForwardView{buff}, PlusOneMutable{});
36     assert(base(transformView.begin().base()) == buff);
37     assert(*transformView.begin() == 1);
38   }
39 
40   {
41     std::ranges::transform_view transformView(InputView{buff}, PlusOneMutable{});
42     assert(base(transformView.begin().base()) == buff);
43     assert(*transformView.begin() == 1);
44   }
45 
46   {
47     const std::ranges::transform_view transformView(MoveOnlyView{buff}, PlusOne{});
48     assert(*transformView.begin() == 1);
49   }
50 
51   static_assert(!BeginInvocable<const std::ranges::transform_view<MoveOnlyView, PlusOneMutable>>);
52 
53   return true;
54 }
55 
56 int main(int, char**) {
57   test();
58   static_assert(test());
59 
60   return 0;
61 }
62