gistfile1.scala

trait Fresh[N] { 
  def fresh:N 
}

class Term[N](implicit F: Fresh[N]) { 
  def foo = "made a " + F.fresh 
}

val ti = new Term[Int] // won't compile

implicit val FreshInt = new Fresh[Int] { 
  val nums = (1 to Int.MaxValue).iterator
  def fresh = nums.next
}

val ti = new Term[Int] // now it will compile

ti.foo // made a 1
ti.foo // made a 2