Scala Collections Pimp to add distinctBy(hash: ... => ...) for hash filterings

gistfile1.scala

implicit def seq2Distinct[T, C[T] <: Seq[T]](tees: C[T]) = new {
 import collection.generic.CanBuildFrom
 import collection.mutable.{HashSet => MutableHashSet}

 def distinctBy[S](hash: T => S)(implicit cbf: CanBuildFrom[C[T],T,C[T]]): C[T] = {
   val builder = cbf()
   val seen = MutableHashSet[S]()

   for (t <- tees) {
     if (!seen(hash(t))) {
       builder += t
       seen += hash(t)
     }
   }

   builder.result
 }
}


case class Content(id: Int, body: String)

val test = List(Content(1,"1"), Content(1,"2"), Content(2,"2"), Content(2,"2"), Content(3,"3"), Content(4,"4"), Content(5,"5"))

test.distinct
test distinctBy { _.id }