Error code E0584

A doc comment that is not attached to anything has been encountered.

Erroneous code example:

#![allow(unused)]
fn main() {
trait Island {
    fn lost();

    //doc.rust-lang.org/ I'm lost!
}
}

A little reminder: a doc comment has to be placed before the item it’s supposed to document. So if you want to document the Island trait, you need to put a doc comment before it, not inside it. Same goes for the lost method: the doc comment needs to be before it:

#![allow(unused)]
fn main() {
//doc.rust-lang.org/ I'm THE island!
trait Island {
    //doc.rust-lang.org/ I'm lost!
    fn lost();
}
}