Type class technique as used in Scalaz 7 for method injection

MethodInjection.scala

package org.uarun.typeclasses

object Main extends ToDoubleOps {
  def main(args: Array[String]) {
    val x = 100
    println(s"$x doubled is ${x.doubled}")
  }
}

trait DoubleOps[A] {
  val self: A
  val m: Numeric[A]
  def doubled: A = m.plus(self, self)
}

trait ToDoubleOps {
  implicit def toDoubleOps[A: Numeric](a: A): DoubleOps[A] = new DoubleOps[A] {
    val self: A = a
    val m: Numeric[A] = implicitly[Numeric[A]]
  }
}