diff --git a/src/wp-includes/class-walker-nav-menu.php b/src/wp-includes/class-walker-nav-menu.php
index 171243b1b9..06070ed0c8 100644
--- a/src/wp-includes/class-walker-nav-menu.php
+++ b/src/wp-includes/class-walker-nav-menu.php
@@ -50,7 +50,7 @@ class Walker_Nav_Menu extends Walker {
 	 * @param int      $depth  Depth of menu item. Used for padding.
 	 * @param stdClass $args   An object of wp_nav_menu() arguments.
 	 */
-	public function start_lvl( &$output, $depth = 0, $args = array() ) {
+	public function start_lvl( &$output, $depth = 0, $args = null ) {
 		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
 			$t = '';
 			$n = '';
@@ -89,7 +89,7 @@ class Walker_Nav_Menu extends Walker {
 	 * @param int      $depth  Depth of menu item. Used for padding.
 	 * @param stdClass $args   An object of wp_nav_menu() arguments.
 	 */
-	public function end_lvl( &$output, $depth = 0, $args = array() ) {
+	public function end_lvl( &$output, $depth = 0, $args = null ) {
 		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
 			$t = '';
 			$n = '';
@@ -115,7 +115,7 @@ class Walker_Nav_Menu extends Walker {
 	 * @param stdClass $args   An object of wp_nav_menu() arguments.
 	 * @param int      $id     Current item ID.
 	 */
-	public function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
+	public function start_el( &$output, $item, $depth = 0, $args = null, $id = 0 ) {
 		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
 			$t = '';
 			$n = '';
@@ -259,7 +259,7 @@ class Walker_Nav_Menu extends Walker {
 	 * @param int      $depth  Depth of page. Not Used.
 	 * @param stdClass $args   An object of wp_nav_menu() arguments.
 	 */
-	public function end_el( &$output, $item, $depth = 0, $args = array() ) {
+	public function end_el( &$output, $item, $depth = 0, $args = null ) {
 		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
 			$t = '';
 			$n = '';