libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp

   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
  10 // <optional>
  11
  12 // constexpr bool optional<T>::has_value() const noexcept;
  13
  14 #include <optional>
  15 #include <type_traits>
  16 #include <cassert>
  17
  18 #include "test_macros.h"
  19
  20 int main(int, char**)
  21 {
  22     using std::optional;
  23     {
  24         const optional<int> opt; ((void)opt);
  25         ASSERT_NOEXCEPT(opt.has_value());
  26         ASSERT_SAME_TYPE(decltype(opt.has_value()), bool);
  27     }
  28     {
  29         constexpr optional<int> opt;
  30         static_assert(!opt.has_value(), "");
  31     }
  32     {
  33         constexpr optional<int> opt(0);
  34         static_assert(opt.has_value(), "");
  35     }
  36
  37   return 0;
  38 }