object Thing {
  implicit class ThingOps1(val x: String) extends AnyVal {
    def fn[A] : Ordering[A] = new Ordering[A] {
      def compare(x1: A, x2: A): Int = ???
    }
  }
  implicit class ThingOps2[A](val x: String) extends AnyVal {
    def fn: Ordering[A] = new Ordering[A] {
      def compare(x1: A, x2: A): Int = ???
    }
  }
}
// a.scala:3: error: object creation impossible, since method compare
// in trait Ordering of type (x: A, y: A)Int is not defined
//     def fn[A] : Ordering[A] = new Ordering[A] {
//                                   ^
// a.scala:8: error: object creation impossible, since method compare
// in trait Ordering of type (x: A, y: A)Int is not defined
//     def fn: Ordering[A] = new Ordering[A] {
//                               ^
// two errors found

implicit class ThingOps1(val x: String) extends AnyVal {
  def fn: Ordering[Boolean] = new Ordering[Boolean] {
    def compare(x1: Boolean, x2: Boolean): Int = ???
  }
}

  class Ord[A](f: (A, A) => Int) extends Ordering[A] { 
    def compare(x1: A, x2: A): Int = f(x1, x2)
  }
  implicit class ThingOps1(val x: String) extends AnyVal {
    def fn[A] : Ordering[A] = new Ord[A]((x1, x2) => ???)
  }