Array length is not bigger than a negative number

[asterite]

fn main() {
  assert!([1i].len() > -1);
}

This assertion incorrectly fails.

[asterite]

Forgot this:

$ rustc --version
rustc 0.12.0-pre (3570095e3 2014-08-19 10:20:54 +0000)

[killercup]

I'm quite certain this is because array length is an unsigned integer and your -1 is cast to an unsigned int as well. Basically, this is a duplicate of #5477.

fn main() {
    let a = [1i];
    let mut b = a.len();
    println!("{}", b);
    b = -1;
    println!("{}", b);
}

prints

1
18446744073709551615

[emberian]

Closing as dup of #5477. This isn't a bug, but can be surprising.

[asterite]

And it will be, approximately two or three times a month in your forums. Good luck :-)