diff --git a/collects/typed-racket/env/lexical-env.rkt b/collects/typed-racket/env/lexical-env.rkt
index 9b9509df..d977186e 100644
--- a/collects/typed-racket/env/lexical-env.rkt
+++ b/collects/typed-racket/env/lexical-env.rkt
@@ -53,11 +53,17 @@
                                           [(syntax-procedure-converted-arguments-property i)
                                            => (λ (prop)
                                                 (define orig (car (flatten prop)))
-                                                (define t (kw-convert (lookup-type/lexical orig env)))
+                                                (define pre-t
+                                                  (lookup-type/lexical orig env
+                                                    #:fail (lambda (i) (lookup-fail i) #f)))
+                                                (define t (if pre-t
+                                                              (kw-convert pre-t)
+                                                              Err))
                                                 (register-type i t)
                                                 t)]
                                           [else ((or fail lookup-fail) i)]))))))
 
+
 ;; refine the type of i in the lexical env
 ;; (identifier type -> type) identifier -> environment
 ;; a macro for inlining :(
diff --git a/collects/typed-racket/types/kw-types.rkt b/collects/typed-racket/types/kw-types.rkt
index a1e0a307..b204773a 100644
--- a/collects/typed-racket/types/kw-types.rkt
+++ b/collects/typed-racket/types/kw-types.rkt
@@ -111,6 +111,6 @@
              [(arr: mand rng rest drest kws)
               (convert kws mand v rng rest drest split?)])))
        (make-Poly names (apply cl->* fns))]
-      [_ (int-err 'kw-convert "non-function type" ft)]))
+      [_ (int-err "kw-convert: non-function type ~a" ft)]))
 
 (provide kw-convert)