named.scala

class A           {          def f(x: Int, y: Int) = ((x, y)) }
class B extends A { override def f(y: Int, x: Int) = ((y, x)) }

object Test {
  val b = new B
  def main(args: Array[String]): Unit = {
    println((b: A).f(x = 1, y = 2))  // (1,2)
    println((b: B).f(x = 1, y = 2))  // (2,1)
    println((b: A).f(1, 2))          // (1,2)
    println((b: B).f(1, 2))          // (1,2)
  }
}