-
Notifications
You must be signed in to change notification settings - Fork 32
/
overloaded_deref_with_ref_pattern.rs
107 lines (88 loc) · 2.52 KB
/
overloaded_deref_with_ref_pattern.rs
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
//@ run-pass
#![allow(unused_mut)]
#![allow(unused_variables)]
// Test that we choose Deref or DerefMut appropriately based on mutability of ref bindings (#15609).
use std::ops::{Deref, DerefMut};
struct DerefOk<T>(T);
struct DerefMutOk<T>(T);
impl<T> Deref for DerefOk<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl<T> DerefMut for DerefOk<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
panic!()
}
}
impl<T> Deref for DerefMutOk<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
panic!()
}
}
impl<T> DerefMut for DerefMutOk<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
fn main() {
// Check that mutable ref binding in match picks DerefMut
let mut b = DerefMutOk(0);
match *b {
ref mut n => n,
};
// Check that mutable ref binding in let picks DerefMut
let mut y = DerefMutOk(1);
let ref mut z = *y;
// Check that immutable ref binding in match picks Deref
let mut b = DerefOk(2);
match *b {
ref n => n,
};
// Check that immutable ref binding in let picks Deref
let mut y = DerefOk(3);
let ref z = *y;
// Check that mixed mutable/immutable ref binding in match picks DerefMut
let mut b = DerefMutOk((0, 9));
match *b {
(ref mut n, ref m) => (n, m),
};
let mut b = DerefMutOk((0, 9));
match *b {
(ref n, ref mut m) => (n, m),
};
// Check that mixed mutable/immutable ref binding in let picks DerefMut
let mut y = DerefMutOk((1, 8));
let (ref mut z, ref a) = *y;
let mut y = DerefMutOk((1, 8));
let (ref z, ref mut a) = *y;
// Check that multiple immutable ref bindings in match picks Deref
let mut b = DerefOk((2, 7));
match *b {
(ref n, ref m) => (n, m),
};
// Check that multiple immutable ref bindings in let picks Deref
let mut y = DerefOk((3, 6));
let (ref z, ref a) = *y;
// Check that multiple mutable ref bindings in match picks DerefMut
let mut b = DerefMutOk((4, 5));
match *b {
(ref mut n, ref mut m) => (n, m),
};
// Check that multiple mutable ref bindings in let picks DerefMut
let mut y = DerefMutOk((5, 4));
let (ref mut z, ref mut a) = *y;
}
// ferrocene-annotations: fls_qztk0bkju9u
// Borrow Expression
//
// ferrocene-annotations: fls_vhpwge5123cm
// Generic Parameters
//
// ferrocene-annotations: fls_fk2m2irwpeof
// Implementations
//
// ferrocene-annotations: fls_9ucqbbd0s2yo
// Struct Types