理解使用＆＃34;这个：SomeClassOrTrait =＆gt;＆＃34;在斯卡拉

Question

以下CoreActors中的“ this：Core =＆gt; ”是什么。

import akka.actor.ActorSystem
import com.demo.service.DemoService
import com.typesafe.config.ConfigFactory

trait Core {
  implicit def system: ActorSystem
}

trait BootedCore extends Core {
  implicit lazy val system = ActorSystem("demo-microservice-system")

  sys.addShutdownHook(system.shutdown())
}

trait ConfigHolder {
  val config = ConfigFactory.load()
}

trait CoreActors extends ConfigHolder {
  this: Core =>

  val demoService = system.actorOf(
    DemoService.props("identity"), "DemoService")

  val services: Services = Map(
    "demoService" -> demoService
  )
}