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
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
// run-pass
use std::cell::RefCell;
use std::convert::TryInto;
#[derive(Default)]
struct DropOrderCollector(RefCell<Vec<u32>>);
struct LoudDrop<'a>(&'a DropOrderCollector, u32);
impl Drop for LoudDrop<'_> {
fn drop(&mut self) {
println!("{}", self.1);
self.0.0.borrow_mut().push(self.1);
}
}
impl DropOrderCollector {
fn option_loud_drop(&self, n: u32) -> Option<LoudDrop> {
Some(LoudDrop(self, n))
}
fn loud_drop(&self, n: u32) -> LoudDrop {
LoudDrop(self, n)
}
fn print(&self, n: u32) {
println!("{}", n);
self.0.borrow_mut().push(n)
}
fn if_(&self) {
if self.option_loud_drop(1).is_some() {
self.print(2);
}
if self.option_loud_drop(3).is_none() {
unreachable!();
} else if self.option_loud_drop(4).is_some() {
self.print(5);
}
if {
if self.option_loud_drop(7).is_some() && self.option_loud_drop(6).is_some() {
self.loud_drop(8);
true
} else {
false
}
} {
self.print(9);
}
}
fn if_let(&self) {
if let None = self.option_loud_drop(2) {
unreachable!();
} else {
self.print(1);
}
if let Some(_) = self.option_loud_drop(4) {
self.print(3);
}
if let Some(_d) = self.option_loud_drop(6) {
self.print(5);
}
}
fn match_(&self) {
match self.option_loud_drop(2) {
_any => self.print(1),
}
match self.option_loud_drop(4) {
_ => self.print(3),
}
match self.option_loud_drop(6) {
Some(_) => self.print(5),
_ => unreachable!(),
}
match {
let _ = self.loud_drop(7);
let _d = self.loud_drop(9);
self.print(8);
()
} {
() => self.print(10),
}
match {
match self.option_loud_drop(14) {
_ => {
self.print(11);
self.option_loud_drop(13)
}
}
} {
_ => self.print(12),
}
match {
loop {
break match self.option_loud_drop(16) {
_ => {
self.print(15);
self.option_loud_drop(18)
}
};
}
} {
_ => self.print(17),
}
}
fn assert_sorted(self) {
assert!(
self.0
.into_inner()
.into_iter()
.enumerate()
.all(|(idx, item)| idx + 1 == item.try_into().unwrap())
);
}
}
fn main() {
println!("-- if --");
let collector = DropOrderCollector::default();
collector.if_();
collector.assert_sorted();
println!("-- if let --");
let collector = DropOrderCollector::default();
collector.if_let();
collector.assert_sorted();
println!("-- match --");
let collector = DropOrderCollector::default();
collector.match_();
collector.assert_sorted();
}
|
