libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.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 // XFAIL: availability-bad_optional_access-missing && !no-exceptions
  13
  14 // constexpr T& optional<T>::value() &&;
  15
  16 #include <optional>
  17 #include <type_traits>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21
  22 using std::optional;
  23 using std::bad_optional_access;
  24
  25 struct X
  26 {
  27     X() = default;
  28     X(const X&) = delete;
  29     constexpr int test() const & {return 3;}
  30     int test() & {return 4;}
  31     constexpr int test() const && {return 5;}
  32     int test() && {return 6;}
  33 };
  34
  35 struct Y
  36 {
  37     constexpr int test() && {return 7;}
  38 };
  39
  40 constexpr int
  41 test()
  42 {
  43     optional<Y> opt{Y{}};
  44     return std::move(opt).value().test();
  45 }
  46
  47 int main(int, char**)
  48 {
  49     {
  50         optional<X> opt; ((void)opt);
  51         ASSERT_NOT_NOEXCEPT(std::move(opt).value());
  52         ASSERT_SAME_TYPE(decltype(std::move(opt).value()), X&&);
  53     }
  54     {
  55         optional<X> opt;
  56         opt.emplace();
  57         assert(std::move(opt).value().test() == 6);
  58     }
  59 #ifndef TEST_HAS_NO_EXCEPTIONS
  60     {
  61         optional<X> opt;
  62         try
  63         {
  64             (void)std::move(opt).value();
  65             assert(false);
  66         }
  67         catch (const bad_optional_access&)
  68         {
  69         }
  70     }
  71 #endif
  72     static_assert(test() == 7, "");
  73
  74   return 0;
  75 }