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// constexpr const T& optional<T>::operator*() const &;
13
14#include <optional>
15#include <type_traits>
16#include <cassert>
17
18#include "test_macros.h"
19
20using std::optional;
21
22struct X
23{
24 constexpr int test() const& {return 3;}
25 int test() & {return 4;}
26 constexpr int test() const&& {return 5;}
27 int test() && {return 6;}
28};
29
30struct Y
31{
32 int test() const {return 2;}
33};
34
35int main(int, char**)
36{
37 {
38 const optional<X> opt; ((void)opt);
39 ASSERT_SAME_TYPE(decltype(*opt), X const&);
40 LIBCPP_STATIC_ASSERT(noexcept(*opt));
41 // ASSERT_NOT_NOEXCEPT(*opt);
42 // FIXME: This assertion fails with GCC because it can see that
43 // (A) operator*() is constexpr, and
44 // (B) there is no path through the function that throws.
45 // It's arguable if this is the correct behavior for the noexcept
46 // operator.
47 // Regardless this function should still be noexcept(false) because
48 // it has a narrow contract.
49 }
50 {
51 constexpr optional<X> opt(X{});
52 static_assert((*opt).test() == 3, "");
53 }
54 {
55 constexpr optional<Y> opt(Y{});
56 assert((*opt).test() == 2);
57 }
58
59 return 0;
60}
61

source code of libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp