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// struct nullopt_t{see below}; 13// constexpr nullopt_t nullopt(unspecified); 14 15#include <experimental/optional> 16#include <type_traits> 17 18#if _LIBCPP_STD_VER > 11 19 20using std::experimental::optional; 21using std::experimental::nullopt_t; 22using std::experimental::nullopt; 23 24constexpr 25int 26test(const nullopt_t&) 27{ 28 return 3; 29} 30 31#endif 32 33int main() 34{ 35#if _LIBCPP_STD_VER > 11 36 static_assert((std::is_class<nullopt_t>::value), ""); 37 static_assert((std::is_empty<nullopt_t>::value), ""); 38 static_assert((std::is_literal_type<nullopt_t>::value), ""); 39 static_assert((!std::is_default_constructible<nullopt_t>::value), ""); 40 41 static_assert(test(nullopt) == 3, ""); 42#endif 43} 44