pdt.scala

gistfile1.scala

trait Foo[A] {
  type Out
  def apply(): Out
}

object Foo {
  type Aux[A, B] = Foo[A] { type Out = B }
  
  implicit val bfoo: Aux[Bar, Int] = new Foo[Bar] {
    type Out = Int
    def apply(): Int = 42
  }
}

trait Bar

object DepType {
  def foo[A](implicit fooOp: Foo[A]): fooOp.Out = fooOp()
  
  def main(args: Array[String]): Unit = {
    println(foo[Bar])
  }
  
}