1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <optional>
// UNSUPPORTED: c++03, c++11, c++14
// template<class T>
// optional(T) -> optional<T>;
#include <optional>
#include <cassert>
#include "test_macros.h"
struct A {};
int main(int, char**)
{
// Test the explicit deduction guides
{
// optional(T)
std::optional opt(5);
ASSERT_SAME_TYPE(decltype(opt), std::optional<int>);
assert(static_cast<bool>(opt));
assert(*opt == 5);
}
{
// optional(T)
std::optional opt(A{});
ASSERT_SAME_TYPE(decltype(opt), std::optional<A>);
assert(static_cast<bool>(opt));
}
{
// optional(const T&);
const int& source = 5;
std::optional opt(source);
ASSERT_SAME_TYPE(decltype(opt), std::optional<int>);
assert(static_cast<bool>(opt));
assert(*opt == 5);
}
{
// optional(T*);
const int* source = nullptr;
std::optional opt(source);
ASSERT_SAME_TYPE(decltype(opt), std::optional<const int*>);
assert(static_cast<bool>(opt));
assert(*opt == nullptr);
}
{
// optional(T[]);
int source[] = {1, 2, 3};
std::optional opt(source);
ASSERT_SAME_TYPE(decltype(opt), std::optional<int*>);
assert(static_cast<bool>(opt));
assert((*opt)[0] == 1);
}
// Test the implicit deduction guides
{
// optional(optional);
std::optional<char> source('A');
std::optional opt(source);
ASSERT_SAME_TYPE(decltype(opt), std::optional<char>);
assert(static_cast<bool>(opt) == static_cast<bool>(source));
assert(*opt == *source);
}
return 0;
}
|
