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# Error code E0426

An undeclared label was used.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    loop {
        break 'a; // error: use of undeclared label `'a`
    }
    }

Please verify you spelled or declared the label correctly. Example:

    #![allow(unused)]
    fn main() {
    'a: loop {
        break 'a; // ok!
    }
    }