diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-let.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-let.rkt
index 6823b56a..8394847e 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-let.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-let.rkt
@@ -100,9 +100,7 @@
                                     ;; if so, add to the table of functions with
                                     ;; unboxed params, so we can modify its call
                                     ;; sites, its body and its header
-                                    (dict-set! unboxed-funs-table fun-name
-                                               (list (reverse unboxed)
-                                                     (reverse boxed))))]
+                                    (add-unboxed-fun! fun-name unboxed boxed))]
                               [(and (equal? (car doms) -FloatComplex)
                                     (could-be-unboxed-in?
                                      (car params) #'(begin body ...)))
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-tables.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-tables.rkt
index 25c3fd00..0d46442c 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-tables.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/unboxed-tables.rkt
@@ -6,6 +6,7 @@
 
 (provide
   unboxed-funs-table
+  add-unboxed-fun!
   add-unboxed-var!
   unboxed-var)
 
@@ -35,3 +36,6 @@
 ;; the new calling convention for these functions have all real parts of unboxed
 ;; params first, then all imaginary parts, then all boxed arguments
 (define unboxed-funs-table (make-free-id-table))
+
+(define (add-unboxed-fun! fun-name unboxed boxed)
+  (dict-set! unboxed-funs-table fun-name (list unboxed boxed)))