I'm trying to define a structural type defining anything that has an "add" method (for instance, a java collection or a java map). Using this, I want to define a few higher order functions that operate on a certain collection

object GenericTypes {
  type GenericCollection[T] = { def add(value: T): java.lang.Boolean}
}

import GenericTypes._
trait HigherOrderFunctions[T, CollectionType[X] <: GenericCollection[X]] {
    def map[V](fn: (T) => V): CollectionType[V]
    ....
}

class RichJList[T](list: List[T]) extends HigherOrderFunctions[T, java.util.List]

This does not compile with the following error

error: Parameter type in structural refinement may not refer to abstract type defined outside that same refinement 

I tried removing the parameter on GenericCollection and putting it on the method:

object GenericTypes {
  type GenericCollection = { def add[T](value: T): java.lang.Boolean}
}
import GenericTypes._
trait HigherOrderFunctions[T, CollectionType[X] <: GenericCollection]

class RichJList[T](list: List[T]) extends HigherOrderFunctions[T, java.util.List]

but I get another error:

error: type arguments [T,java.util.List] do not conform to trait HigherOrderFunctions's type parameter bounds [T,CollectionType[X] <: org.scala_tools.javautils.j2s.GenericTypes.GenericCollection]

Can anyone give me some advice on how to use structural typing with abstract typed parameters in Scala? Or how to achieve what I'm looking to accomplish? Thanks so much!