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 T&& optional<T>::operator*() &&;
13 
14 #include <optional>
15 #include <type_traits>
16 #include <cassert>
17 
18 #include "test_macros.h"
19 
20 using std::optional;
21 
22 struct X
23 {
testX24     constexpr int test() const& {return 3;}
testX25     int test() & {return 4;}
testX26     constexpr int test() const&& {return 5;}
testX27     int test() && {return 6;}
28 };
29 
30 struct Y
31 {
testY32     constexpr int test() && {return 7;}
33 };
34 
35 constexpr int
test()36 test()
37 {
38     optional<Y> opt{Y{}};
39     return (*std::move(opt)).test();
40 }
41 
main(int,char **)42 int main(int, char**)
43 {
44     {
45         optional<X> opt; ((void)opt);
46         ASSERT_SAME_TYPE(decltype(*std::move(opt)), X&&);
47         // ASSERT_NOT_NOEXCEPT(*std::move(opt));
48         // FIXME: This assertion fails with GCC because it can see that
49         // (A) operator*() is constexpr, and
50         // (B) there is no path through the function that throws.
51         // It's arguable if this is the correct behavior for the noexcept
52         // operator.
53         // Regardless this function should still be noexcept(false) because
54         // it has a narrow contract.
55     }
56     {
57         optional<X> opt(X{});
58         assert((*std::move(opt)).test() == 6);
59     }
60     static_assert(test() == 7, "");
61 
62     return 0;
63 }
64