diff --git a/collects/mzlib/contract.rkt b/collects/mzlib/contract.rkt
index b5152e0..c8f9724 100644
--- a/collects/mzlib/contract.rkt
+++ b/collects/mzlib/contract.rkt
@@ -2,11 +2,13 @@
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
-;;  provide arrow contracts from our local copy
+;;  provide arrow contracts from our local copy (mostly)
 ;;
 
 (require "private/contract-arrow.rkt")
 (provide (all-from-out "private/contract-arrow.rkt"))
+(require (only-in racket/contract unconstrained-domain->))
+(provide unconstrained-domain->)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
@@ -15,6 +17,18 @@
 (require "private/contract-object.rkt")
 (provide (all-from-out "private/contract-object.rkt"))
 
+(require (only-in racket/class
+                  is-a?/c
+                  implementation?/c
+                  subclass?/c
+                  mixin-contract
+                  make-mixin-contract))
+(provide is-a?/c
+         implementation?/c
+         subclass?/c
+         mixin-contract
+         make-mixin-contract)
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 ;; old-style define/contract
@@ -54,13 +68,16 @@
          racket/contract/private/basic-opters
          racket/contract/combinator)
 
+
+(define (build-flat-contract name pred) (make-predicate-contract name pred))
+
 (provide 
  opt/c define-opt/c ;(all-from "private/contract-opt.rkt")
  (except-out (all-from-out racket/contract/private/ds)
              contract-struct)
  
- (all-from-out racket/contract/private/base)
- (all-from-out racket/contract/private/provide)
+ (all-from-out racket/contract/private/base
+               racket/contract/private/provide)
  (except-out (all-from-out racket/contract/private/misc)
              check-between/c
              string-len/c
@@ -69,8 +86,17 @@
  (rename-out [string-len/c string/len])
  (except-out (all-from-out racket/contract/private/guts)
              check-flat-contract
-             check-flat-named-contract)
- (all-from-out racket/contract/private/prop
-               racket/contract/private/blame
-               racket/contract/combinator))
-
+             check-flat-named-contract
+             make-predicate-contract)
+ (except-out (all-from-out racket/contract/private/blame)
+             make-blame)
+ (except-out (all-from-out racket/contract/private/prop)
+             chaperone-contract-struct?
+             contract-struct-first-order
+             contract-struct-name
+             contract-struct-projection
+             contract-struct-stronger?
+             contract-struct?
+             flat-contract-struct?)
+ (all-from-out racket/contract/combinator)
+ build-flat-contract)
diff --git a/collects/mzlib/private/contract-arrow.rkt b/collects/mzlib/private/contract-arrow.rkt
index 6471de6..6c40637 100644
--- a/collects/mzlib/private/contract-arrow.rkt
+++ b/collects/mzlib/private/contract-arrow.rkt
@@ -22,51 +22,12 @@
          ->pp-rest
          case->
          opt->
-         opt->*
-         unconstrained-domain->)
+         opt->*)
 
 (define-struct contracted-function (proc ctc)
   #:property prop:procedure 0
   #:property prop:contracted 1)
 
-(define-syntax (unconstrained-domain-> stx)
-  (syntax-case stx ()
-    [(_ rngs ...)
-     (with-syntax ([(rngs-x ...) (generate-temporaries #'(rngs ...))]
-                   [(proj-x ...) (generate-temporaries #'(rngs ...))]
-                   [(p-app-x ...) (generate-temporaries #'(rngs ...))]
-                   [(res-x ...) (generate-temporaries #'(rngs ...))])
-       #'(let ([rngs-x (coerce-contract 'unconstrained-domain-> rngs)] ...)
-           (let ([proj-x (contract-projection rngs-x)] ...)
-             (define name
-               (build-compound-type-name 'unconstrained-domain-> (contract-name rngs-x) ...))
-             (define (proj wrapper)
-               (λ (blame)
-                 (let* ([p-app-x (proj-x blame)] ...
-                        [res-checker (λ (res-x ...) (values (p-app-x res-x) ...))])
-                   (λ (val)
-                     (if (procedure? val)
-                         (wrapper
-                          val
-                          (make-keyword-procedure
-                           (λ (kwds kwd-vals . args)
-                             (apply values res-checker kwd-vals args))
-                           (λ args
-                             (apply values res-checker args)))
-                          impersonator-prop:contracted ctc)
-                         (raise-blame-error blame val "expected a procedure"))))))
-             (define ctc
-               (if (and (chaperone-contract? rngs-x) ...)
-                   (make-chaperone-contract
-                    #:name name
-                    #:projection (proj chaperone-procedure)
-                    #:first-order procedure?)
-                   (make-contract
-                    #:name name
-                    #:projection (proj impersonate-procedure)
-                    #:first-order procedure?)))
-             ctc)))]))
-
 (define (build--> name doms doms-rest rngs kwds quoted-kwds rng-any? func)
   (let ([doms/c (map (λ (dom) (coerce-contract name dom)) doms)]
         [rngs/c (map (λ (rng) (coerce-contract name rng)) rngs)]
diff --git a/collects/mzlib/private/contract-object.rkt b/collects/mzlib/private/contract-object.rkt
index 57b9ee0..1a5840b 100644
--- a/collects/mzlib/private/contract-object.rkt
+++ b/collects/mzlib/private/contract-object.rkt
@@ -10,12 +10,7 @@
                      racket/contract/private/helpers
                      "contract-arr-obj-helpers.rkt"))
 
-(provide mixin-contract
-         make-mixin-contract
-         is-a?/c 
-         subclass?/c 
-         implementation?/c
-         object-contract)
+(provide object-contract)
 
 (define-syntax object-contract
   (let ()
@@ -303,46 +298,4 @@
                   ctc))))]))))
 
 
-(define (make-mixin-contract . %/<%>s)
-  ((and/c (flat-contract class?)
-          (apply and/c (map sub/impl?/c %/<%>s)))
-   . ->d .
-   subclass?/c))
 
-(define (subclass?/c %)
-  (unless (class? %)
-    (error 'subclass?/c "expected <class>, given: ~e" %))
-  (let ([name (object-name %)])
-    (flat-named-contract
-     `(subclass?/c ,(or name 'unknown%))
-     (lambda (x) (subclass? x %)))))
-
-(define (implementation?/c <%>)
-  (unless (interface? <%>)
-    (error 'implementation?/c "expected <interface>, given: ~e" <%>))
-  (let ([name (object-name <%>)])
-    (flat-named-contract
-     `(implementation?/c ,(or name 'unknown<%>))
-     (lambda (x) (implementation? x <%>)))))
-
-(define (sub/impl?/c %/<%>)
-  (cond
-    [(interface? %/<%>) (implementation?/c %/<%>)]
-    [(class? %/<%>) (subclass?/c %/<%>)]
-    [else (error 'make-mixin-contract "unknown input ~e" %/<%>)]))
-
-(define (is-a?/c <%>)
-  (unless (or (interface? <%>)
-              (class? <%>))
-    (error 'is-a?/c "expected <interface> or <class>, given: ~e" <%>))
-  (let ([name (object-name <%>)])
-    (flat-named-contract
-     (cond
-       [name
-        `(is-a?/c ,name)]
-       [(class? <%>)
-        `(is-a?/c unknown%)]
-       [else `(is-a?/c unknown<%>)])
-     (lambda (x) (is-a? x <%>)))))
-
-(define mixin-contract (class? . ->d . subclass?/c))