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
|
//@ run-pass
#![allow(dead_code)]
pub fn main() {
let x = Some(3);
if let Some(y) = x {
assert_eq!(y, 3);
} else {
panic!("`if let` panicked");
}
let mut worked = false;
if let Some(_) = x {
worked = true;
}
assert!(worked);
let clause: usize;
if let None = Some("test") {
clause = 1;
} else if 4_usize > 5 {
clause = 2;
} else if let Ok(()) = Err::<(),&'static str>("test") {
clause = 3;
} else {
clause = 4;
}
assert_eq!(clause, 4_usize);
if 3 > 4 {
panic!("bad math");
} else if let 1 = 2 {
panic!("bad pattern match");
}
enum Foo {
One,
Two(usize),
Three(String, isize)
}
let foo = Foo::Three("three".to_string(), 42);
if let Foo::One = foo {
panic!("bad pattern match");
} else if let Foo::Two(_x) = foo {
panic!("bad pattern match");
} else if let Foo::Three(s, _) = foo {
assert_eq!(s, "three");
} else {
panic!("bad else");
}
if false {
panic!("wat");
} else if let a@Foo::Two(_) = Foo::Two(42_usize) {
if let Foo::Two(b) = a {
assert_eq!(b, 42_usize);
} else {
panic!("panic in nested `if let`");
}
}
}
|
