gistfile1.scala

  def moveAttack[A <: MovableFighter](
    world: World, unit: A,
    target: SearchRes[OwnedObj], strict: Boolean=true
  )(implicit ev: A#Self =:= A): Result[A] = {
    moveAndThen(world, unit, target.path, strict) { case (newWorld, movedUnit) =>
      movedUnit.attackWS(target.value, newWorld).right.map(_.map {
        case (w, u) => (w, u)
      })
    }
  }