How to implement From on Borrow for higher kinded types?

help
1

I've seen how Borrow can help provide implementations for both &T and T but what tricks exist when T is a higher-kinded type?:


use aws_smithy_runtime_api::client::result::SdkError;

impl<E, R> From<SdkError<E, R>> for Error
where
    E: std::error::Error + Send + Sync + CreateUnhandledError + 'static,
    R: std::fmt::Debug + Send + Sync + 'static,
{
    fn from(err: SdkError<E, R>) -> Self {
        do_conversion_stuff(&err)
    }
}

impl<E, R> From<&SdkError<E, R>> for Error
where
    E: std::error::Error + Send + Sync + CreateUnhandledError + 'static,
    R: std::fmt::Debug + Send + Sync + 'static,
{
    fn from(err: &SdkError<E, R>) -> Self {
        do_conversion_stuff(err)
    }
}

In this case I would think adding another generic, S: Borrow<SdkError<E, R>> would work, but then there's no way to infer E and R.

So more broadly how can I avoid typing everything twice in this case?