Wrong hint about needless_range_loop

[BusyJay]

Clippy warns about following snippet:

let v = vec![5; 10];
for i in 0..v.len() - 2 {
    println!("{}", v[i + 2] - v[i]);
}

It suggest me to use enumerate. But I don't think I can use enumerate in this situation.

[Manishearth]

.enumerate().first(v.len()-2)

It looks more complicated but you don't have to worry about bounds checks.

[BusyJay]

No, I need to access two items at different position. In this case, I need to access i + 2 and i.

[oli-obk]

I think the proper way would be something like

for (&a, &b) in v[2..].iter().zip(&v) {
    println!("{}", a - b);
}

[Manishearth]

(While there are ways of doing this with iterators, the hint should still be improved)

[BusyJay]

@oli-obk I think my version is more clean and simple. :)

[oli-obk]

@BusyJay you need to specify the 2 two times ;) mine is less readable for sure, but that's mainly b/c we don't have good ways to zip like for (&a, &b) in (&v[2..], &v) {}

[BusyJay]

Maybe windows is a good choice in this situation.

[y21]

Is this issue still relevant today? It doesn't seem to lint on the code provided anymore: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=ac000dbc5a08cd445b4babe76f6176bf

[Manishearth]

Yeah that lint has gotten tons of improvement but we probably had duplicate issues filed. Nice catch!