如何在Scala中组合类型类？

/**
  * A divisor that operates on real numbers.
  */
case class RealDivisor(divisor: Long)
  extends Divisor[Double,Double]
  with Divisor[Long,Double] // ... with Divisor[Int,Double],etc.
  {

  override def divide(dividend: Double): Double =
    if (divisor != 0) dividend / divisor.toDouble else 0

  def divide(dividend: Long): Double = divide(dividend.toDouble)

}

我宁愿能做这样的事情：

case class RealDivisor(divisor: Long) extends Divisor[A: Numeric] {
  // ...
}

因此,我只需要实现一次除法.我该怎么办？