ScalaPB type class instance on the generated message companion object

Question

Suppose there is a proto MyMessage and a type class TypeClass[T].

Is it possible to have a custom instance TypeClass[MyMessage] in the generated companion object of MyMessage, so any (implicit TypeClass[Message]) would get automatically resolved without any import?

The solution I've thought of is to have a trait defining the implicit instance

trait MyMessageCompanionTrait {
  implicit val myMessageType = new TypeClass[MyMessage] = ???
}

and then make that extend the companion object

message MyMessage {
  option (scalapb.message).companion_extends = "MyMessageCompanionTrait";

  int32 field = 1;
}

Obviously this adds a circular dependency in the build.