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
|
use std::ops::Add;
#[derive(Copy, Clone)]
struct Point {
x: isize,
y: isize,
}
impl Add<isize> for Point {
type Output = isize;
fn add(self, z: isize) -> isize {
self.x + self.y + z
}
}
impl Point {
pub fn times(&self, z: isize) -> isize {
self.x * self.y * z
}
}
fn a() {
let mut p = Point {x: 3, y: 4};
// ok (we can loan out rcvr)
p + 3;
p.times(3);
}
fn b() {
let mut p = Point {x: 3, y: 4};
// Here I create an outstanding loan and check that we get conflicts:
let q = &mut p;
p + 3; //~ ERROR cannot use `p`
p.times(3); //~ ERROR cannot borrow `p`
*q + 3; // OK to use the new alias `q`
q.x += 1; // and OK to mutate it
}
fn main() {
}
|
