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// constexpr const T& optional<T>::value() const; 1301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 140cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow#include <experimental/optional> 1501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#include <type_traits> 1601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#include <cassert> 1701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11 1901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 200cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clowusing std::experimental::optional; 210cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow 2201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantstruct X 2301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{ 2401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant constexpr int test() const {return 3;} 2501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant int test() {return 4;} 2601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant}; 2701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 2801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif // _LIBCPP_STD_VER > 11 2901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 3001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantint main() 3101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{ 3201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11 3301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant { 340cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow constexpr optional<X> opt; 3501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant static_assert(opt.value().test() == 3, ""); 3601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant } 3701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#else 3801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#error 3901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif // _LIBCPP_STD_VER > 11 4001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant} 41