Index: nav-menu-template.php
===================================================================
--- nav-menu-template.php	(revision 31782)
+++ nav-menu-template.php	(working copy)
@@ -148,6 +148,8 @@
 			}
 		}
 
+		$args = (object) $args;
+
 		$item_output = $args->before;
 		$item_output .= '<a'. $attributes .'>';
 		/** This filter is documented in wp-includes/post-template.php */