| 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() { |
| } |