FailDay.scala

(0 to Int.MaxValue) == Range() // empty!

class X extends Actor {
  def act {
    val a = actor {
      loop {
        receive { // FAIL, must use 'self.receive'
          case ... 
        }
      }
    }
  }
}

class X extends Actor {
  def act {
    loop {
        computeSomething (not react/receive) // FAIL, it blocks all actors
    }
  }
}



def gimmeSize[A,B](m: Map[A,B]) = m.size

val m = scala.collection.mutable.Map[String, Int]()

gimmeSize(m)
//<console>:8: error: type mismatch;
// found   : scala.collection.mutable.Map[String,Int]
// required: Map[?,?]
//       s(m)

// By default 'Map' is 'scala.collection.immutable.Map' and shared trait betwen 
// mutable and immutable map is 'scala.collection.Map'

// Correct version:
def gimmeSize[A,B](m: scala.collection.Map[A,B]) = m.size