class Opal::Rewriters::MlhsArgs

def on_def(node)
  node = super(node)
  mid, args, body = *node
  arguments = Arguments.new(args)
  args = args.updated(nil, arguments.rewritten)
  if arguments.initialization
    body ||= s(:nil) # prevent returning mlhs assignment
    body = prepend_to_body(body, arguments.initialization)
  end
  node.updated(nil, [mid, args, body])
end