rust/tests/ui/self_assignment.rs
Tomasz Miąsko 4f4abf4e06 Warn about explicit self-assignment
Warn about assignments where left-hand side place expression is the same
as right-hand side value expression. For example, warn about assignment in:

```rust
pub struct Event {
    id: usize,
    x: i32,
    y: i32,
}

pub fn copy_position(a: &mut Event, b: &Event) {
    a.x = b.x;
    a.y = a.y;
}
```
2020-08-16 23:31:36 +02:00

68 lines
1.2 KiB
Rust

#![warn(clippy::self_assignment)]
pub struct S<'a> {
a: i32,
b: [i32; 10],
c: Vec<Vec<i32>>,
e: &'a mut i32,
f: &'a mut i32,
}
pub fn positives(mut a: usize, b: &mut u32, mut s: S) {
a = a;
*b = *b;
s = s;
s.a = s.a;
s.b[10] = s.b[5 + 5];
s.c[0][1] = s.c[0][1];
s.b[a] = s.b[a];
*s.e = *s.e;
s.b[a + 10] = s.b[10 + a];
let mut t = (0, 1);
t.1 = t.1;
t.0 = (t.0);
}
pub fn negatives_not_equal(mut a: usize, b: &mut usize, mut s: S) {
dbg!(&a);
a = *b;
dbg!(&a);
s.b[1] += s.b[1];
s.b[1] = s.b[2];
s.c[1][0] = s.c[0][1];
s.b[a] = s.b[*b];
s.b[a + 10] = s.b[a + 11];
*s.e = *s.f;
let mut t = (0, 1);
t.0 = t.1;
}
#[allow(clippy::eval_order_dependence)]
pub fn negatives_side_effects() {
let mut v = vec![1, 2, 3, 4, 5];
let mut i = 0;
v[{
i += 1;
i
}] = v[{
i += 1;
i
}];
fn next(n: &mut usize) -> usize {
let v = *n;
*n += 1;
v
}
let mut w = vec![1, 2, 3, 4, 5];
let mut i = 0;
let i = &mut i;
w[next(i)] = w[next(i)];
w[next(i)] = w[next(i)];
}
fn main() {}