Index: wp-includes/nav-menu-template.php
===================================================================
--- wp-includes/nav-menu-template.php	(revision 15303)
+++ wp-includes/nav-menu-template.php	(working copy)
@@ -311,6 +311,7 @@
 		$classes = (array) $menu_item->classes;
 		$classes[] = 'menu-item';
 		$classes[] = 'menu-item-type-' . $menu_item->type;
+		$classes[] = 'menu-item-object-' . $menu_item->object;
 
 		// if the menu item corresponds to a taxonomy term for the currently-queried non-hierarchical post object
 		if ( $wp_query->is_singular && 'taxonomy' == $menu_item->type && in_array( $menu_item->object_id, $possible_object_parents ) ) {