1. Vulnerability Description

• Using AsInstanceOf, IsInstanceOf to deduce types can lead to incorrect type reasoning and unexpected errors. In particular, since Scala has a type erase at the time of compilation, the developer must know the type of variable explicitly.

2. Vulnerability Countermeasure

• Use pattern matching for Type to explicitly enable type-specific processing.

3. Sample Code

• Pattern matching example

abstract class Device
case class Phone(model: String) extends Device {
  def screenOff = "Turning screen off"
}
case class Computer(model: String) extends Device {
  def screenSaverOn = "Turning screen saver on..."
}

def goIdle(device: Device) = device match {
  case p: Phone => p.screenOff
  case c: Computer => c.screenSaverOn
}