Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.860
diff -u -p -r1.860 common.inc
--- includes/common.inc	31 Jan 2009 19:07:45 -0000	1.860
+++ includes/common.inc	2 Feb 2009 00:18:04 -0000
@@ -1884,12 +1884,8 @@ function drupal_page_footer() {
  */
 function drupal_map_assoc($array, $function = NULL) {
   if (!isset($function)) {
-    $result = array();
-    foreach ($array as $value) {
-      $result[$value] = $value;
-    }
-    return $result;
-  }
+    return array_combine($array, $array);
+  }
   elseif (function_exists($function)) {
     $result = array();
     foreach ($array as $value) {