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// template <class U> constexpr T optional<T>::value_or(U&& v) const&;
13
14#include <optional>
15#include <type_traits>
16#include <cassert>
17
18#include "test_macros.h"
19
20using std::optional;
21
22struct Y
23{
24 int i_;
25
26 constexpr Y(int i) : i_(i) {}
27};
28
29struct X
30{
31 int i_;
32
33 constexpr X(int i) : i_(i) {}
34 constexpr X(const Y& y) : i_(y.i_) {}
35 constexpr X(Y&& y) : i_(y.i_+1) {}
36 friend constexpr bool operator==(const X& x, const X& y)
37 {return x.i_ == y.i_;}
38};
39
40int main(int, char**)
41{
42 {
43 constexpr optional<X> opt(2);
44 constexpr Y y(3);
45 static_assert(opt.value_or(u: y) == 2, "");
46 }
47 {
48 constexpr optional<X> opt(2);
49 static_assert(opt.value_or(u: Y(3)) == 2, "");
50 }
51 {
52 constexpr optional<X> opt;
53 constexpr Y y(3);
54 static_assert(opt.value_or(u: y) == 3, "");
55 }
56 {
57 constexpr optional<X> opt;
58 static_assert(opt.value_or(u: Y(3)) == 4, "");
59 }
60 {
61 const optional<X> opt(2);
62 const Y y(3);
63 assert(opt.value_or(y) == 2);
64 }
65 {
66 const optional<X> opt(2);
67 assert(opt.value_or(Y(3)) == 2);
68 }
69 {
70 const optional<X> opt;
71 const Y y(3);
72 assert(opt.value_or(y) == 3);
73 }
74 {
75 const optional<X> opt;
76 assert(opt.value_or(Y(3)) == 4);
77 }
78
79 return 0;
80}
81

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