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 // <optional> 11 12 // struct nullopt_t{see below}; 13 // inline constexpr nullopt_t nullopt(unspecified); 14 15 // [optional.nullopt]/2: 16 // Type nullopt_t shall not have a default constructor or an initializer-list 17 // constructor, and shall not be an aggregate. 18 19 #include <optional> 20 #include <type_traits> 21 22 #include "test_macros.h" 23 24 using std::nullopt_t; 25 using std::nullopt; 26 test()27constexpr bool test() 28 { 29 nullopt_t foo{nullopt}; 30 (void)foo; 31 return true; 32 } 33 main(int,char **)34int main(int, char**) 35 { 36 static_assert(std::is_empty_v<nullopt_t>); 37 static_assert(!std::is_default_constructible_v<nullopt_t>); 38 39 static_assert(std::is_same_v<const nullopt_t, decltype(nullopt)>); 40 static_assert(test()); 41 42 return 0; 43 } 44