1//===----------------------------------------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is dual licensed under the MIT and the University of Illinois Open 6// Source Licenses. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10// <optional> 11 12// constexpr const T& optional<T>::value() const; 13 14#include <experimental/optional> 15#include <type_traits> 16#include <cassert> 17 18#if _LIBCPP_STD_VER > 11 19 20using std::experimental::optional; 21 22struct X 23{ 24 constexpr int test() const {return 3;} 25 int test() {return 4;} 26}; 27 28#endif // _LIBCPP_STD_VER > 11 29 30int main() 31{ 32#if _LIBCPP_STD_VER > 11 33 { 34 constexpr optional<X> opt; 35 static_assert(opt.value().test() == 3, ""); 36 } 37#else 38#error 39#endif // _LIBCPP_STD_VER > 11 40} 41