scala> collection.mutable.Buffer()
val res0: collection.mutable.Buffer[Nothing] = ArrayBuffer()
scala> import collection.mutable
scala> mutable.Buffer()
val res1: mutable.Buffer[Nothing] = ArrayBuffer()
scala> import collection.mutable.ArrayBuffer
scala> ArrayBuffer(1, 2, 3)
val res2: ArrayBuffer[Int] = ArrayBuffer(1, 2, 3)
scala> import collection.mutable.{Buffer => B}
scala> B()
val res3: B[Nothing] = ArrayBuffer()
