diff --git a/collects/typed-scheme/env/lexical-env.ss b/collects/typed-scheme/env/lexical-env.ss
index 51b7d22e..5e64695a 100644
--- a/collects/typed-scheme/env/lexical-env.ss
+++ b/collects/typed-scheme/env/lexical-env.ss
@@ -3,8 +3,9 @@
 (require (except-in "../utils/utils.ss" extend))
 (require "type-environments.ss" 
 	 "type-env.ss"
+	 unstable/mutated-vars
          (only-in scheme/contract ->* ->)
-         (utils tc-utils mutated-vars)
+         (utils tc-utils)
          (only-in (rep type-rep) Type/c)
 	 (except-in (types utils convenience) -> ->*))
 
diff --git a/collects/typed-scheme/private/type-contract.ss b/collects/typed-scheme/private/type-contract.ss
index 2c305836..07a5d1cb 100644
--- a/collects/typed-scheme/private/type-contract.ss
+++ b/collects/typed-scheme/private/type-contract.ss
@@ -17,7 +17,7 @@
  mzlib/trace
  scheme/list
  (only-in scheme/contract -> ->* case-> cons/c flat-rec-contract provide/contract any/c)
- (for-template scheme/base scheme/contract (utils poly-c) (only-in scheme/class object% is-a?/c subclass?/c)))
+ (for-template scheme/base scheme/contract unstable/poly-c (only-in scheme/class object% is-a?/c subclass?/c)))
 
 (define (define/fixup-contract? stx)
   (or (syntax-property stx 'typechecker:contract-def)
diff --git a/collects/typed-scheme/typecheck/tc-if.ss b/collects/typed-scheme/typecheck/tc-if.ss
index 1584e867..5e037518 100644
--- a/collects/typed-scheme/typecheck/tc-if.ss
+++ b/collects/typed-scheme/typecheck/tc-if.ss
@@ -8,7 +8,7 @@
                     [remove *remove])
          (env lexical-env type-environments)
          (r:infer infer)
-	 (utils tc-utils mutated-vars)
+	 (utils tc-utils)
          (typecheck tc-envops tc-metafunctions)
          syntax/kerncase
          mzlib/trace
diff --git a/collects/typed-scheme/typecheck/tc-toplevel.ss b/collects/typed-scheme/typecheck/tc-toplevel.ss
index a14e0125..793eefb8 100644
--- a/collects/typed-scheme/typecheck/tc-toplevel.ss
+++ b/collects/typed-scheme/typecheck/tc-toplevel.ss
@@ -11,7 +11,8 @@
          (types utils convenience)
          (private parse-type type-annotation type-contract)
          (env type-env init-envs type-name-env type-alias-env lexical-env)
-         (utils tc-utils mutated-vars)
+	 unstable/mutated-vars
+         (utils tc-utils)
          "provide-handling.ss"
          "def-binding.ss"
          (for-template
diff --git a/collects/typed-scheme/utils/mutated-vars.ss b/collects/unstable/mutated-vars.ss
similarity index 92%
rename from collects/typed-scheme/utils/mutated-vars.ss
rename to collects/unstable/mutated-vars.ss
index a362bd53..1e141c54 100644
--- a/collects/typed-scheme/utils/mutated-vars.ss
+++ b/collects/unstable/mutated-vars.ss
@@ -1,8 +1,7 @@
 #lang scheme/base
 
 (require (for-template scheme/base)
-         syntax/boundmap syntax/kerncase
-         mzlib/trace)
+         syntax/boundmap syntax/kerncase)
 
 ;; mapping telling whether an identifer is mutated
 ;; maps id -> boolean
@@ -33,12 +32,12 @@
                                          (fmv/list #'b))]
     [(letrec-values ([_ e] ...) . b) (begin (fmv/list #'(e ...))
                                             (fmv/list #'b))]
+    [(letrec-syntaxes+values _ ([_ e] ...) . b) (begin (fmv/list #'(e ...))
+						       (fmv/list #'b))]
     [(#%expression e) (find-mutated-vars #'e)]
     ;; all the other forms don't have any expression subforms (like #%top)
     [_ (void)]))
 
-;(trace find-mutated-vars)
-
 ;; checks to see if a particular variable is ever set!'d
 ;; is-var-mutated? : identifier -> boolean
 (define (is-var-mutated? id) (module-identifier-mapping-get table id (lambda _ #f)))