) $menu_items as $key => $parent_item ) {
		$classes                                   = (array) $parent_item->classes;
		$menu_items[ $key ]->current_item_ancestor = false;
		$menu_items[ $key ]->current_item_parent   = false;

		if (
			isset( $parent_item->type )
			&& (
				// Ancestral post object.
				(
					'post_type' === $parent_item->type
					&& ! empty( $queried_object->post_type )
					&& is_post_type_hierarchical( $queried_object->post_type )
					&& in_array( (int) $parent_item->object_id, $queried_object->ancestors, true )
					&& $parent_item->object != $queried_object->ID
				) ||

				// Ancestral term.
				(
					'taxonomy' === $parent_item->type
					&& isset( $possible_taxonomy_ancestors[ $parent_item->object ] )
					&& in_array( (int) $parent_item->object_id, $possible_taxonomy_ancestors[ $parent_item->object ], true )
					&& (
						! isset( $queried_object->term_id ) ||
						$parent_item->object_id != $queried_object->term_id
					)
				)
			)
		) {
			if ( ! empty( $queried_object->taxonomy ) ) {
				$classes[] = 'current-' . $queried_object->taxonomy . '-ancestor';
			} else {
				$classes[] = 'current-' . $queried_object->post_type . '-ancestor';
			}
		}

		if ( in_array( (int) $parent_item->db_id, $active_ancestor_item_ids, true ) ) {
			$classes[] = 'current-menu-ancestor';

			$menu_items[ $key ]->current_item_ancestor = true;
		}
		if ( in_array( (int) $parent_item->db_id, $active_parent_item_ids, true ) ) {
			$classes[] = 'current-menu-parent';

			$menu_items[ $key ]->current_item_parent = true;
		}
		if ( in_array( (int) $parent_item->object_id, $active_parent_object_ids, true ) ) {
			$classes[] = 'current-' . $active_object . '-parent';
		}

		if ( 'post_type' === $parent_item->type && 'page' === $parent_item->object ) {
			// Back compat classes for pages to match wp_page_menu().
			if ( in_array( 'current-menu-parent', $classes, true ) ) {
				$classes[] = 'current_page_parent';
			}
			if ( in_array( 'current-menu-ancestor', $classes, true ) ) {
				$classes[] = 'current_page_ancestor';
			}
		}

		$menu_items[ $key ]->classes = array_unique( $classes );
	}
}

/**
 * Retrieves the HTML list content for nav menu items.
 *
 * @uses Walker_Nav_Menu to create HTML list content.
 * @since 3.0.0
 *
 * @param array    $items The menu items, sorted by each menu item's menu order.
 * @param int      $depth Depth of the item in reference to parents.
 * @param stdClass $args  An object containing wp_nav_menu() arguments.
 * @return string The HTML list content for the menu items.
 */
function walk_nav_menu_tree( $items, $depth, $args ) {
	$walker = ( empty( $args->walker ) ) ? new Walker_Nav_Menu() : $args->walker;

	return $walker->walk( $items, $depth, $args );
}

/**
 * Prevents a menu item ID from being used more than once.
 *
 * @since 3.0.1
 * @access private
 *
 * @param string $id
 * @param object $item
 * @return string
 */
function _nav_menu_item_id_use_once( $id, $item ) {
	static $_used_ids = array();

	if ( in_array( $item->ID, $_used_ids, true ) ) {
		return '';
	}

	$_used_ids[] = $item->ID;

	return $id;
}

/**
 * Remove the `menu-item-has-children` class from bottom level menu items.
 *
 * This runs on the {@see 'nav_menu_css_class'} filter. The $args and $depth
 * parameters were added after the filter was originally introduced in
 * WordPress 3.0.0 so this needs to allow for cases in which the filter is
 * called without them.
 *
 * @see https://core.trac.wordpress.org/ticket/56926
 *
 * @since 6.2.0
 *
 * @param string[]       $classes   Array of the CSS classes that are applied to the menu item's `<li>` element.
 * @param WP_Post        $menu_item The current menu item object.
 * @param stdClass|false $args      An object of wp_nav_menu() arguments. Default false ($args unspecified when filter is called).
 * @param int|false      $depth     Depth of menu item. Default false ($depth unspecified when filter is called).
 * @return string[] Modified nav menu classes.
 */
function wp_nav_menu_remove_menu_item_has_children_class( $classes, $menu_item, $args = false, $depth = false ) {
	/*
	 * Account for the filter being called without the $args or $depth parameters.
	 *
	 * This occurs when a theme uses a custom walker calling the `nav_menu_css_class`
	 * filter using the legacy formats prior to the introduction of the $args and
	 * $depth parameters.
	 *
	 * As both of these parameters are required for this function to determine
	 * both the current and maximum depth of the menu tree, the function does not
	 * attempt to remove the `menu-item-has-children` class if these parameters
	 * are not set.
	 */
	if ( false === $depth || false === $args ) {
		return $classes;
	}

	// Max-depth is 1-based.
	$max_depth = isset( $args->depth ) ? (int) $args->depth : 0;
	// Depth is 0-based so needs to be increased by one.
	$depth = $depth + 1;

	// Complete menu tree is displayed.
	if ( 0 === $max_depth ) {
		return $classes;
	}

	/*
	 * Remove the `menu-item-has-children` class from bottom level menu items.
	 * -1 is used to display all menu items in one level so the class should
	 * be removed from all menu items.
	 */
	if ( -1 === $max_depth || $depth >= $max_depth ) {
		$classes = array_diff( $classes, array( 'menu-item-has-children' ) );
	}

	return $classes;
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class 'Walker_Nav_Menu' not found in /home/islamicf/public_html/wp-content/plugins/coming-soon/app/nestednavmenu.php:48
Stack trace:
#0 /home/islamicf/public_html/wp-content/plugins/coming-soon/app/load_controller.php(20): require_once()
#1 /home/islamicf/public_html/wp-content/plugins/coming-soon/coming-soon.php(129): require_once('/home/islamicf/...')
#2 /home/islamicf/public_html/wp-settings.php(517): include_once('/home/islamicf/...')
#3 /home/islamicf/public_html/wp-config.php(99): require_once('/home/islamicf/...')
#4 /home/islamicf/public_html/wp-load.php(50): require_once('/home/islamicf/...')
#5 /home/islamicf/public_html/wp-blog-header.php(13): require_once('/home/islamicf/...')
#6 /home/islamicf/public_html/index.php(17): require('/home/islamicf/...')
#7 {main}
  thrown in <b>/home/islamicf/public_html/wp-content/plugins/coming-soon/app/nestednavmenu.php</b> on line <b>48</b><br />