code: @Override
      public R visitModule(ModuleElement e, P p) {
          return scan(e.getEnclosedElements(), p); // TODO: Hmmm, this might not be right
      }
docs: Visits a {@code ModuleElement} by scanning the enclosed
  elements.
  
  @param e the element to visit
  @param p a visitor-specified parameter
  @return  the result of the scan