False positive for unnecessary_filter_map

[emabee]

cargo clippy -V
clippy 0.0.212 (e3cb40e 2019-06-25)

A warning is produced from

#[warn(clippy::unnecessary_filter_map)]
let errors: Vec<ServerError> = server_errors
    .into_iter()
    .filter_map(|se| match se.severity() {
        Severity::Warning => {
            self.warnings.push(se);
            None
        }
        _ => Some(se),
    })
    .collect();

The code splits moves some items from one collection into a second. If I'd use filter, as recommended, then I would have to clone the ses, and discard the original instances.

[ghost]

duplicate of #4433 .
please close 😉