gistfile1.scala

import scala.reflect._

trait History

case class SlotHistory(t: Int) extends History

case class RouletteHistory(t: String) extends History

def test[T <: History : ClassTag](): T = {
  classTag[T].runtimeClass match {
    case h if h.isAssignableFrom(classOf[SlotHistory]) ⇒ SlotHistory(1).asInstanceOf[T]
    case h if h.isAssignableFrom(classOf[RouletteHistory]) ⇒ RouletteHistory("One").asInstanceOf[T]
  }
}