libcxx/test/std/utilities/optional/optional.object/optional.object.observe/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
  11 // XFAIL: availability-bad_optional_access-missing && !no-exceptions
  12
  13 // <optional>
  14
  15 // constexpr T& optional<T>::value() &;
  16
  17 #include <optional>
  18 #include <type_traits>
  19 #include <cassert>
  20
  21 #include "test_macros.h"
  22
  23 using std::optional;
  24 using std::bad_optional_access;
  25
  26 struct X
  27 {
  28     X() = default;
  29     X(const X&) = delete;
  30     constexpr int test() const & {return 3;}
  31     int test() & {return 4;}
  32     constexpr int test() const && {return 5;}
  33     int test() && {return 6;}
  34 };
  35
  36 struct Y
  37 {
  38     constexpr int test() & {return 7;}
  39 };
  40
  41 constexpr int
  42 test()
  43 {
  44     optional<Y> opt{Y{}};
  45     return opt.value().test();
  46 }
  47
  48
  49 int main(int, char**)
  50 {
  51     {
  52         optional<X> opt; ((void)opt);
  53         ASSERT_NOT_NOEXCEPT(opt.value());
  54         ASSERT_SAME_TYPE(decltype(opt.value()), X&);
  55     }
  56     {
  57         optional<X> opt;
  58         opt.emplace();
  59         assert(opt.value().test() == 4);
  60     }
  61 #ifndef TEST_HAS_NO_EXCEPTIONS
  62     {
  63         optional<X> opt;
  64         try
  65         {
  66             (void)opt.value();
  67             assert(false);
  68         }
  69         catch (const bad_optional_access&)
  70         {
  71         }
  72     }
  73 #endif
  74     static_assert(test() == 7, "");
  75
  76   return 0;
  77 }