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