title: Automatic casting in Scala
body: <p>I have a class that inherits the Actor trait.  In my code, I have a method that creates <code>x</code> numbers of this actor using a loop and another method that simply sends the Finish message to all of them to tell them to terminate.  I made the kill method just take an array of Actor since I want to be able to use it with an array of any type of Actor.  For some reason, however, when I pass a value of type Array[Producer], where Producer extends Actor, to a method that accepts the type Array[Actor], I get a type error.  Shouldn't Scala see that Producer is a type of Actor and automatically cast this?</p>