Specifying the error type for TryFrom implementations

[tpoliaw]

Would it be possible to allow users to specify the error type returned from TryFrom implementations? Something like

#[derive(From)]
struct UnknownMode(u8);

#[derive(TryFrom)]
#[try_from(repr, error = UnknownMode)]
#[repr(u8)]
enum Mode {
    Foo,
    Bar,
}

where the given error has to implement From<T> where T is the type for which TryFrom<T> is being implemented.