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 // <ranges>
14 
15 // template<class T>
16 // concept view = ...;
17 
18 #include <ranges>
19 
20 #include "test_macros.h"
21 
22 // The type would be a view, but it's not moveable.
23 struct NotMoveable : std::ranges::view_base {
24   NotMoveable() = default;
25   NotMoveable(NotMoveable&&) = delete;
26   NotMoveable& operator=(NotMoveable&&) = delete;
27   friend int* begin(NotMoveable&);
28   friend int* begin(NotMoveable const&);
29   friend int* end(NotMoveable&);
30   friend int* end(NotMoveable const&);
31 };
32 static_assert(std::ranges::range<NotMoveable>);
33 static_assert(!std::movable<NotMoveable>);
34 static_assert(std::default_initializable<NotMoveable>);
35 static_assert(std::ranges::enable_view<NotMoveable>);
36 static_assert(!std::ranges::view<NotMoveable>);
37 
38 // The type would be a view, but it's not default initializable
39 struct NotDefaultInit : std::ranges::view_base {
40   NotDefaultInit() = delete;
41   friend int* begin(NotDefaultInit&);
42   friend int* begin(NotDefaultInit const&);
43   friend int* end(NotDefaultInit&);
44   friend int* end(NotDefaultInit const&);
45 };
46 static_assert(std::ranges::range<NotDefaultInit>);
47 static_assert(std::movable<NotDefaultInit>);
48 static_assert(!std::default_initializable<NotDefaultInit>);
49 static_assert(std::ranges::enable_view<NotDefaultInit>);
50 static_assert(std::ranges::view<NotDefaultInit>);
51 
52 // The type would be a view, but it doesn't enable it with enable_view
53 struct NotExplicitlyEnabled {
54   NotExplicitlyEnabled() = default;
55   NotExplicitlyEnabled(NotExplicitlyEnabled&&) = default;
56   NotExplicitlyEnabled& operator=(NotExplicitlyEnabled&&) = default;
57   friend int* begin(NotExplicitlyEnabled&);
58   friend int* begin(NotExplicitlyEnabled const&);
59   friend int* end(NotExplicitlyEnabled&);
60   friend int* end(NotExplicitlyEnabled const&);
61 };
62 static_assert(std::ranges::range<NotExplicitlyEnabled>);
63 static_assert(std::movable<NotExplicitlyEnabled>);
64 static_assert(std::default_initializable<NotExplicitlyEnabled>);
65 static_assert(!std::ranges::enable_view<NotExplicitlyEnabled>);
66 static_assert(!std::ranges::view<NotExplicitlyEnabled>);
67 
68 // The type has everything else, but it's not a range
69 struct NotARange : std::ranges::view_base {
70   NotARange() = default;
71   NotARange(NotARange&&) = default;
72   NotARange& operator=(NotARange&&) = default;
73 };
74 static_assert(!std::ranges::range<NotARange>);
75 static_assert(std::movable<NotARange>);
76 static_assert(std::default_initializable<NotARange>);
77 static_assert(std::ranges::enable_view<NotARange>);
78 static_assert(!std::ranges::view<NotARange>);
79 
80 // The type satisfies all requirements
81 struct View : std::ranges::view_base {
82   View() = default;
83   View(View&&) = default;
84   View& operator=(View&&) = default;
85   friend int* begin(View&);
86   friend int* begin(View const&);
87   friend int* end(View&);
88   friend int* end(View const&);
89 };
90 static_assert(std::ranges::range<View>);
91 static_assert(std::movable<View>);
92 static_assert(std::default_initializable<View>);
93 static_assert(std::ranges::enable_view<View>);
94 static_assert(std::ranges::view<View>);
95