Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1254
diff -u -r1.1254 common.inc
--- includes/common.inc	14 Nov 2010 21:04:45 -0000	1.1254
+++ includes/common.inc	17 Nov 2010 00:10:39 -0000
@@ -2235,7 +2235,9 @@
  * @param array $options
  *   An associative array of additional options, with the following elements:
  *   - 'attributes': An associative array of HTML attributes to apply to the
- *     anchor tag.
+ *     anchor tag. If element 'class' is included, it must be an array; 'title'
+ *     must be a string; other elements are more flexible, as they just need
+ *     to work in a call to drupal_attributes($options['attributes']).
  *   - 'html' (default FALSE): Whether $text is HTML or just plain-text. For
  *     example, to make an image tag into a link, this must be set to TRUE, or
  *     you will see the escaped HTML image tag.