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 
20 using std::optional;
21 
22 struct X
23 {
testX24     constexpr int test() const {return 3;}
25 };
26 
27 struct Y
28 {
testY29     int test() const noexcept {return 2;}
30 };
31 
32 struct Z
33 {
34     const Z* operator&() const;
testZ35     constexpr int test() const {return 1;}
36 };
37 
main(int,char **)38 int main(int, char**)
39 {
40     {
41         const std::optional<X> opt; ((void)opt);
42         ASSERT_SAME_TYPE(decltype(opt.operator->()), X const*);
43         // ASSERT_NOT_NOEXCEPT(opt.operator->());
44         // FIXME: This assertion fails with GCC because it can see that
45         // (A) operator->() is constexpr, and
46         // (B) there is no path through the function that throws.
47         // It's arguable if this is the correct behavior for the noexcept
48         // operator.
49         // Regardless this function should still be noexcept(false) because
50         // it has a narrow contract.
51     }
52     {
53         constexpr optional<X> opt(X{});
54         static_assert(opt->test() == 3, "");
55     }
56     {
57         constexpr optional<Y> opt(Y{});
58         assert(opt->test() == 2);
59     }
60     {
61         constexpr optional<Z> opt(Z{});
62         static_assert(opt->test() == 1, "");
63     }
64 
65     return 0;
66 }
67