Index: codegen.scm
===================================================================
--- codegen.scm	(revision 33693)
+++ codegen.scm	(working copy)
@@ -129,12 +129,12 @@
 	   (indent
 	    (lambda ()
 	      (let ((y (walk y dest loc)))
-		(emit nl t " = " y ";"))))
+		(unless (eq? y 'undefined) (emit nl t " = " y ";")))))
 	   (emit nl "}" nl "else {")
 	   (indent
 	    (lambda ()
 	      (let ((z (walk z dest loc)))
-		(emit nl t " = " z ";"))))
+                (unless (eq? z 'undefined) (emit nl t " = " z ";")))))
 	   (emit nl "}")
 	   t))
 	(('%host-ref name) name)