xref: /llvm-project/libcxx/test/std/ranges/range.utility/range.subrange/lwg3470.pass.cpp (revision b8cb1dc9ea87faa8e8e9ab7a31710a8c0bb8b084)
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 
11 // class std::ranges::subrange;
12 //   Test the example from LWG 3470,
13 //   qualification conversions in __convertible_to_non_slicing
14 
15 #include <ranges>
16 
17 #include <cassert>
18 
19 #include "test_macros.h"
20 
test()21 constexpr bool test()
22 {
23   // The example from LWG3470, using implicit conversion.
24   int a[3] = { 1, 2, 3 };
25   int* b[3] = { &a[2], &a[0], &a[1] };
26   std::ranges::subrange<const int* const*> c = b;
27   assert(c.begin() == b + 0);
28   assert(c.end() == b + 3);
29 
30   // Also test CTAD and a subrange-to-subrange conversion.
31   std::same_as<std::ranges::subrange<int**>> auto d = std::ranges::subrange(b);
32   assert(d.begin() == b + 0);
33   assert(d.end() == b + 3);
34 
35   std::ranges::subrange<const int* const*> e = d;
36   assert(e.begin() == b + 0);
37   assert(e.end() == b + 3);
38 
39   return true;
40 }
41 
main(int,char **)42 int main(int, char**)
43 {
44   test();
45   static_assert(test());
46 
47   return 0;
48 }
49