gistfile1.txt

scala> sealed trait B
defined trait B

scala> case class A(i: Int) extends B
defined class A

scala> implicit class AOps(a: A) {
     | def stuff: Unit = println("A")
     | }
defined class AOps

scala> implicit class BOps(b: B) {
     | def stuff: Unit = println("B")
     | }
defined class BOps

scala> A(1).stuff
A

scala> new B {}.stuff
B