How can an initblock access private member

Question
1 
import scala.util.control.NonFatal

class Base(a: Int)(initBlock: Base => Unit) {

  try (initBlock(this))
  catch {
    case NonFatal(ex) => // ...
  }

  def doSomething(): Unit = println("do something")
}

object MyApp extends App {
  Base(1) { base =>
    base.doSomething()
  }
}

I want the initBlock can access the doSomething even if it’s private, any hint? thanks.