object X
object Y extends X

trait T{
    // some behavior goes here
}

object X extends T

object Y extends T {
    // additional stuff here
}

object X{
  def x = 5
}

object Y{
  import X._
  val y = x
}

object X {
}

object Y {
    def a = 5
}

implicit def xToY(x: X.type) = Y

println(X.a)

class Parent {}

object Parent extends Parent {}

object Child extends Parent {}

object X { def f = 5 }

object Y {
  export X._
  def g = 42
  def h = f * g
}

Y.f // 5
Y.g // 42
Y.h // 210

object X { def f = 5; def g = 6 }
object Y { export X.f }
Y.f // 5
Y.g
^^^
value g is not a member of Y