title: Are DummyImplicits used, and if so, how?
body: <p>While pondering through the code of <code>Predef.scala</code> I noticed the following:</p>
  <pre><code>/** A type for which there is always an implicit value.
   *  @see [[scala.Array$]], method `fallbackCanBuildFrom`
   */
  class DummyImplicit
  
  object DummyImplicit {
  
    /** An implicit value yielding a `DummyImplicit`.
     *   @see [[scala.Array$]], method `fallbackCanBuildFrom`
     */
    implicit def dummyImplicit: DummyImplicit = new DummyImplicit
  }
  </code></pre>
  <p>Does anyone have a clue why this piece of seemingly useless code exists?</p>