diff --git a/collects/typed-racket/rep/rep-utils.rkt b/collects/typed-racket/rep/rep-utils.rkt
index bef2b412..8fc19f35 100644
--- a/collects/typed-racket/rep/rep-utils.rkt
+++ b/collects/typed-racket/rep/rep-utils.rkt
@@ -360,14 +360,4 @@
 (provide/cond-contract (struct Rep ([seq exact-nonnegative-integer?]
                                     [free-vars (hash/c symbol? variance?)]
                                     [free-idxs (hash/c symbol? variance?)]
-                                    [stx (or/c #f syntax?)]))
-                       [replace-syntax (Rep? syntax? . -> . Rep?)])
-
-(define (replace-field val new-val idx)
-  (define-values (type skipped) (struct-info val))
-  (define maker (struct-type-make-constructor type))
-  (define flds (struct->list val))
-  (apply maker (list-set flds idx new-val)))
-
-(define (replace-syntax rep stx)
-  (replace-field rep stx 3))
+                                    [stx (or/c #f syntax?)])))
diff --git a/collects/typed-racket/typecheck/tc-envops.rkt b/collects/typed-racket/typecheck/tc-envops.rkt
index 795b9317..107848f6 100644
--- a/collects/typed-racket/typecheck/tc-envops.rkt
+++ b/collects/typed-racket/typecheck/tc-envops.rkt
@@ -13,6 +13,7 @@
                   env? update-type/lexical env-map env-props replace-props)
          racket/contract racket/match
          unstable/struct
+         unstable/list
          "tc-metafunctions.rkt"
          (for-syntax racket/base))
 
diff --git a/collects/typed-racket/utils/utils.rkt b/collects/typed-racket/utils/utils.rkt
index bbbfde39..b1c9ed66 100644
--- a/collects/typed-racket/utils/utils.rkt
+++ b/collects/typed-racket/utils/utils.rkt
@@ -9,9 +9,6 @@ at least theoretically.
          racket/require-syntax racket/provide-syntax         
          racket/struct-info "timing.rkt")
 
-;; to move to unstable
-(provide list-update list-set)
-
 (provide
  ;; optimization
  optimize?
@@ -157,16 +154,6 @@ at least theoretically.
         [(_ hd ([i c] ...) . opts)
          (define-struct hd (i ...) . opts)])))
 
-(define (list-update l i f)
-  (cond [(null? l) (error 'list-update "list not long enough" l i f)]
-        [(zero? i) (cons (f (car l)) (cdr l))]
-        [else (cons (car l) (list-update (cdr l) (sub1 i) f))]))
-
-(define (list-set l k v)
-  (if (zero? k)
-      (cons v (cdr l))
-      (cons (car l) (list-set (cdr l) (sub1 k) v))))
-
 
 (provide make-struct-info-self-ctor)
 ;Copied from racket/private/define-struct