Out Of Bound compile error with .len() function call

[jbe]

@chrefr

Edit: No, wait, it is not even the cast, it is the fact the a reference was taken.

I think that might be worth opening an issue to fix the lint (not sure how difficult that is though). I believe that taking a shared reference should have no impact here.

Edit: Done, see my post below.

[jbe]

@Cerber-Ursi

Curiously, this code does trigger the lint:

fn main() {
    let xs: [i32; 5] = [1, 2, 3, 4, 5];
    if false {
        println!("{}", xs[7]);
    }
}

...although the problematic code is not only potentially unreachable, but actually unreachable.

See also Issue #90534. I added your example as a comment to that issue.

[jbe]

I opened a new issue #98444 with the following example code:

fn main() {
    let xs: [i32; 5] = [1, 2, 3, 4, 5];
    let _ = &xs; // this line suppresses the `unconditional_panic` lint
    let _ = xs[7];
}

[bjorn3]

@chrefr

Edit: No, wait, it is not even the cast, it is the fact the a reference was taken.

This lint is emitted by the const propagation pass I believe. This pass forgets about the value of locals when a reference is taken.

[juniverse76]

Thank you for taking an action!
Glad I can help.