gistfile1.scala

import language.existentials

trait MetaModel[+M <: Model[M]] {
  def speak:String
}

trait Model[+A <: Model[A]] {
  self: A =>
}

object A1 extends MetaModel[Model1] { def speak="Model1, A1"}
object B1 extends MetaModel[Model1] { def speak="Model1, B1"}
object A2 extends MetaModel[Model2] { def speak="Model2, A2"}

case class Model1(a: Int) extends Model[Model1]
case class Model2(a: Int, b: String) extends Model[Model2]

object MyTest extends App {
  val list = List[MetaModel[T] forSome { type T <: Model[T] }](A1, A2, B1) //Looking to specify type for list.
  list.foreach { x => println(x.speak) }
}