Wrong parameter name

In the body of the method, in "case 'node'" this patch changes $node_type to $object_type - this is incorrect. It should stay $node_type (since we know this is a node by then).

Perhaps a cleaner way to do this, is to do something like:

function vote_up_down_link($type, $object, $teaser = FALSE) {
  switch ($type) {
    case 'node':
      $node = $object; // alias for clarity
      $node_type = in_array($node->type, variable_get('vote_up_down_node_types', array()), TRUE);
      ...
    case 'comment':
      $comment = $object; // alias for clarity
      ...
      $comment->cid

Or even:

function vote_up_down_link($type, $object, $teaser = FALSE) {
  $$type = $object; // type-specific alias for clarity
  ...

Yes, I like this patch now - nice and simple.

Fixed. Thanks!