gistfile1.txt

  implicit def varEqual1[A:Equal]: Equal1[({type λ[α] = Var[A,α]})#λ] = new Equal1[({type λ[α] = Var[A,α]})#λ] {
    def equal[B](a1: ({type λ[α] = Var[A,α]})#λ[B], a2: ({type λ[α] = Var[A,α]})#λ[B])(implicit a: Equal[B]): Boolean =
      implicitly[Equal[({type λ[α] = Var[A,α]})#λ[B]]].equal(a1, a1)
  }

Compare with:

instance Eq a => Eq1 (Var a) where { x === y = x == y }