101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//===----------------------------------------------------------------------===//
201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//
301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//                     The LLVM Compiler Infrastructure
401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//
501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// This file is dual licensed under the MIT and the University of Illinois Open
601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// Source Licenses. See LICENSE.TXT for details.
701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//
801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//===----------------------------------------------------------------------===//
901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
1001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// <optional>
1101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
1201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// template <class T>
1301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// class optional
1401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// {
1501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// public:
1601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//     typedef T value_type;
1701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//     ...
1801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
190cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow#include <experimental/optional>
2001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#include <type_traits>
2101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
2201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11
2301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
240cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clowusing std::experimental::optional;
250cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow
2601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnanttemplate <class Opt, class T>
2701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantvoid
2801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnanttest()
2901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{
3001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant    static_assert(std::is_same<typename Opt::value_type, T>::value, "");
3101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant}
3201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
3301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif  // _LIBCPP_STD_VER > 11
3401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant
3501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantint main()
3601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{
3701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11
380cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow    test<optional<int>, int>();
390cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow    test<optional<const int>, const int>();
400cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow    test<optional<double>, double>();
410cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow    test<optional<const double>, const double>();
4201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif  // _LIBCPP_STD_VER > 11
4301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant}
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