受保護的範圍

受保護的作用域允許從當前類的任何子類訪問該值。

class FooClass {
  protected val x = "foo"
}
class BarClass extends FooClass {
  val y = x // It is a subclass instance, will compile
}
class ClassB {
  val f = new FooClass
  f.x // <- This will not compile
}