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 // UNSUPPORTED: c++03, c++11, c++14, c++17
9 
10 // <chrono>
11 // class day;
12 
13 //  constexpr day& operator--() noexcept;
14 //  constexpr day operator--(int) noexcept;
15 
16 
17 #include <chrono>
18 #include <type_traits>
19 #include <cassert>
20 
21 #include "test_macros.h"
22 
23 template <typename D>
testConstexpr()24 constexpr bool testConstexpr()
25 {
26     D d1{10};
27     if (static_cast<unsigned>(--d1) != 9) return false;
28     if (static_cast<unsigned>(d1--) != 9) return false;
29     if (static_cast<unsigned>(d1)   != 8) return false;
30     return true;
31 }
32 
main(int,char **)33 int main(int, char**)
34 {
35     using day = std::chrono::day;
36     ASSERT_NOEXCEPT(--(std::declval<day&>())  );
37     ASSERT_NOEXCEPT(  (std::declval<day&>())--);
38 
39     ASSERT_SAME_TYPE(day , decltype(  std::declval<day&>()--));
40     ASSERT_SAME_TYPE(day&, decltype(--std::declval<day&>()  ));
41 
42     static_assert(testConstexpr<day>(), "");
43 
44     for (unsigned i = 10; i <= 20; ++i)
45     {
46         day d(i);
47         assert(static_cast<unsigned>(--d) == i - 1);
48         assert(static_cast<unsigned>(d--) == i - 1);
49         assert(static_cast<unsigned>(d)   == i - 2);
50     }
51 
52   return 0;
53 }
54