Scala type erasure gotcha.

gistfile1.scala

// from here http://stackoverflow.com/questions/1094173/how-do-i-get-around-type-erasure-on-scala-or-why-cant-i-get-the-type-paramete

List(1,2,3) match {
     case l : List[String] => println("A list of strings?!")
     case _ => println("Ok")
}

// <console>:9: warning: fruitless type test: a value of type List[Int] cannot also be a List[String] (but still might match its erasure)
//              case l : List[String] => println("A list of strings?!")