Maybe Haskell has some solution .. but it seems just an inherent problem with static typing. It's mostly a matter of boilerplate in a sense.

In Clojure, if in your application you extend a record (say from some library) and implement a new protocol, you've effectively implicitly created a new extended record type. In Clojure that happens transparently b/c its dynamic. In the static typing scenario you have to explicitly create this "extended type" that has the parent type and also implements the new protocol. You'd then explicitly use ExtendedRecordA. It can still be used where the parent was expected.

That's more verbose but maybe manageable.. Now if you have multiple libraries extending one record with different protocols .. and then you have a library/application where you included all these libraries. You want to use all these protocols from that one record.. how do you not do that? you'd need some aggregation step to make ExtendedRecordA and ExtendedRecordB and ExtendedRecordC all come together under some new super-type that has all the protocols. It's not impossible but it's just messier