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
24using std::nullopt_t;
25using std::nullopt;
26
27constexpr bool test()
28{
29 nullopt_t foo{nullopt};
30 (void)foo;
31 return true;
32}
33
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

source code of libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp