dependent types with implicits

T.scala

scala> sealed trait A { type T }
defined trait A

scala> case class AImpl(x: Int) extends A { override type T = Int }
defined class AImpl

scala> case class AImpl2(x: String) extends A { override type T = String }
defined class AImpl2

scala> def f(x: A)(implicit ev: x.T): x.T = ev
f: (x: A)(implicit ev: x.T)x.T

scala> implicit val int: Int = 42
int: Int = 42

scala> implicit val str: String = "foobar"
str: String = foobar

scala> f( AImpl(1) )
res0: Int = 42

scala> f( AImpl2("f") )
res1: String = foobar