Error trait is crucial in usage like converting error to something like Anyhow::Error,which can be used to propagate errors simply. Some functions use Error<()>, but unit type is not Display, so it will not have Error trait.

A workaround looks like this, which requires manual conversion of error.

let serial = bs.open_protocol_exclusive::<Serial>(serial_handle).map_err(|x| anyhow!("Failed to open serial protocol, status {}",x.status()))?;

Due to implementation of a trait cannot overlap, simply do impl<Data: Debug> Display for Error<Data> will not work.