Error code E0576

An associated item wasn't found in the given type.

Erroneous code example:

#![allow(unused)]
fn main() {
trait Hello {
    type Who;

    fn hello() -> <Self as Hello>::You; // error!
}
}

In this example, we tried to use the non-existent associated type You of the Hello trait. To fix this error, use an existing associated type:

#![allow(unused)]
fn main() {
trait Hello {
    type Who;

    fn hello() -> <Self as Hello>::Who; // ok!
}
}