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 T>
15 // class empty_view;
16 
17 #include <ranges>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 
22 template<class T>
23 constexpr void testType() {
24   static_assert(std::ranges::range<std::ranges::empty_view<T>>);
25   static_assert(std::ranges::range<const std::ranges::empty_view<T>>);
26   static_assert(std::ranges::view<std::ranges::empty_view<T>>);
27 
28   std::ranges::empty_view<T> empty;
29 
30   assert(empty.begin() == nullptr);
31   assert(empty.end() == nullptr);
32   assert(empty.data() == nullptr);
33   assert(empty.size() == 0);
34   assert(empty.empty() == true);
35 
36   assert(std::ranges::begin(empty) == nullptr);
37   assert(std::ranges::end(empty) == nullptr);
38   assert(std::ranges::data(empty) == nullptr);
39   assert(std::ranges::size(empty) == 0);
40   assert(std::ranges::empty(empty) == true);
41 }
42 
43 struct Empty {};
44 struct BigType { char buff[8]; };
45 
46 template<class T>
47 concept ValidEmptyView = requires { typename std::ranges::empty_view<T>; };
48 
49 constexpr bool test() {
50   // Not objects:
51   static_assert(!ValidEmptyView<int&>);
52   static_assert(!ValidEmptyView<void>);
53 
54   testType<int>();
55   testType<const int>();
56   testType<int*>();
57   testType<Empty>();
58   testType<const Empty>();
59   testType<BigType>();
60 
61   return true;
62 }
63 
64 int main(int, char**) {
65   test();
66   static_assert(test());
67 
68   return 0;
69 }
70