Index: wp-includes/capabilities.php
===================================================================
--- wp-includes/capabilities.php	(revision 19234)
+++ wp-includes/capabilities.php	(working copy)
@@ -721,7 +721,7 @@
 		foreach ( (array) $this->roles as $oldrole )
 			unset( $this->caps[$oldrole] );
 
-		if ( 1 == count( $this->roles ) && $role == $this->roles[0] )
+		if ( 1 == count( $this->roles ) && $role == current($this->roles) )
 			return;
 
 		if ( !empty( $role ) ) {