Index: wp-includes/class-wp-error.php
===================================================================
--- wp-includes/class-wp-error.php	(revision 17501)
+++ wp-includes/class-wp-error.php	(working copy)
@@ -18,7 +18,7 @@
  * @package WordPress
  * @since 2.1.0
  */
-class WP_Error {
+class WP_Error extends Exception {
 	/**
 	 * Stores the list of errors.
 	 *
@@ -56,7 +56,7 @@
 	 */
 	function WP_Error($code = '', $message = '', $data = '') {
 		if ( empty($code) )
-			return;
+			throw new WP_Error( '', 'Code parameter is missing.' );
 
 		$this->errors[$code][] = $message;