Scala inverted zip extension method

ZipInvert.scala

import language.higherKinds

import collection.GenIterable
import collection.generic.CanBuildFrom

implicit class ZipInvert[A,CC[X] <: GenIterable[X]](coll: CC[A]) {
  def zipInvert[A1 >: A, B, That](that: GenIterable[B])(implicit bf: CanBuildFrom[CC[A], (B, A1), That]): That = {
    val b = bf(coll)
    val these = coll.iterator
    val those = that.iterator
    while (these.hasNext && those.hasNext)
      b += ((those.next, these.next))
    b.result
  }
}

val numberList = List.range(1,5)

numberList zipInvert Stream.continually("a")