Index: masquerade.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/masquerade/masquerade.module,v
retrieving revision 1.29
diff -u -p -r1.29 masquerade.module
--- masquerade.module	22 Jul 2010 13:48:36 -0000	1.29
+++ masquerade.module	22 Jul 2010 17:17:50 -0000
@@ -573,6 +573,7 @@ function masquerade_switch_user($uid) {
   global $user;
 
   if ($user->uid == $uid || isset($user->masquerading)) {
+    watchdog('masquerade', 'This user is already %user.', array('%user' => $new_user->name), WATCHDOG_ERROR);
     return drupal_access_denied();
   }