importImplicitForExtension.scala

import scala.language.higherKinds

// log into a trie data structure
trait LogDSL[L] {
  def (message: String) log: L
}

object LogDSL {
  implicit object LogRecsLogDSL extends LogDSL[String] {
    def (message: String) log = message
  }

  def runLog(ls: String): String = ls
}

trait Direction[D] {
  def (erased d: Direction.type) north: D
}

object Direction {

  implicit def logDirection[L](implicit L: LogDSL[L]): Direction[L] = new {
    override def (erased d: Direction.type) north = "north".log
  }
}

object Main {
  def main(args: Array[String]): Unit = {
//    implicit val ld: Direction[String] = Direction.logDirection[String] // this line makes it work
    import Direction.logDirection // this line doesn't help

    println("North log")
    println(LogDSL.runLog(Direction.logDirection.north(Direction)))
    println(LogDSL.runLog(Direction.north))
  }
}