diff --git a/collects/typed-scheme/info.ss b/collects/typed-scheme/info.ss
new file mode 100644
index 0000000000..e59bcb1832
--- /dev/null
+++ b/collects/typed-scheme/info.ss
@@ -0,0 +1,4 @@
+#lang setup/infotab
+
+(define name "Typed Scheme")
+(define scribblings '(("typed-scheme.scrbl")))
diff --git a/collects/typed-scheme/lang/main.ss b/collects/typed-scheme/lang/main.ss
new file mode 100644
index 0000000000..a31d5925a6
--- /dev/null
+++ b/collects/typed-scheme/lang/main.ss
@@ -0,0 +1,9 @@
+#lang s-exp "minimal.ss"
+           
+(providing (libs (except scheme/base require #%module-begin #%top-interaction with-handlers lambda #%app))
+	   (basics #%module-begin		   		   		   
+		   #%top-interaction
+		   with-handlers
+		   lambda
+		   #%app)
+	   (from scheme require))
diff --git a/collects/typed-scheme/lang/minimal.ss b/collects/typed-scheme/lang/minimal.ss
new file mode 100644
index 0000000000..c732931f44
--- /dev/null
+++ b/collects/typed-scheme/lang/minimal.ss
@@ -0,0 +1,29 @@
+#lang scheme/base
+
+(provide #%module-begin provide require rename-in rename-out prefix-in only-in all-from-out except-out except-in
+         providing begin)
+
+(require (for-syntax scheme/base))
+
+(define-for-syntax ts-mod "../typed-scheme.ss")
+
+(define-syntax (providing stx)
+  (syntax-case stx (libs from basics except)
+    [(form (libs (except lb ex ...) ...) (basics b ...) (from spec id ...) ...)
+     (datum->syntax 
+      stx
+      (syntax->datum
+       (with-syntax ([(b* ...) (generate-temporaries #'(b ...))]
+                     [ts ts-mod])
+         (syntax/loc 
+             stx
+           (begin
+             (require (except-in ts b ...))
+             (require (only-in ts [b b*] ...))
+             (require (except-in lb ex ...) ...)
+             (require (only-in spec id ...) ...)
+             (provide id ...) ...
+             (provide (rename-out [b* b] ...))
+             (provide (all-from-out ts))
+             (provide (all-from-out lb) ...))))))]))
+	
\ No newline at end of file
diff --git a/collects/typed-scheme/lang/reader.ss b/collects/typed-scheme/lang/reader.ss
new file mode 100644
index 0000000000..8794ba5907
--- /dev/null
+++ b/collects/typed-scheme/lang/reader.ss
@@ -0,0 +1,15 @@
+(module reader scheme/base
+  (require (prefix-in r: "../typed-reader.ss")
+	   (only-in syntax/module-reader wrap-read-all))
+  
+  (define (*read in)
+    (wrap-read-all 'typed-scheme/lang/main in r:read))
+  
+  (define (*read-syntax src in)
+    (wrap-read-all 'typed-scheme/lang/main
+		   in
+		   (lambda (in)
+		     (r:read-syntax src in))))
+  
+  (provide (rename-out [*read read] [*read-syntax read-syntax])))
+
diff --git a/collects/typed-scheme/private/base-env.ss b/collects/typed-scheme/private/base-env.ss
new file mode 100644
index 0000000000..514259e871
--- /dev/null
+++ b/collects/typed-scheme/private/base-env.ss
@@ -0,0 +1,570 @@
+#lang scheme/base
+
+(require (for-template (only-in (lib "list.ss") foldl)
+                       scheme/base
+                       '#%paramz
+                       scheme/promise
+                       string-constants/string-constant
+                       #;'#%more-scheme
+                       #;'#%qq-and-or
+                       (lib "match-error.ss" "mzlib" "private" "match"))
+         )
+
+
+(require
+ "extra-procs.ss"
+ scheme/promise
+ (except-in "type-rep.ss" make-arr)
+ (only-in scheme/list cons?)
+ "type-effect-convenience.ss"
+ (only-in "type-effect-convenience.ss" [make-arr* make-arr])
+ "union.ss"
+ string-constants/string-constant
+ (lib "match-error.ss" "mzlib" "private" "match")
+ "tc-structs.ss")
+
+(require (for-syntax
+          scheme/base
+          "init-envs.ss"
+          (except-in "type-rep.ss" make-arr)
+          (only-in (lib "list.ss") foldl)
+          "type-effect-convenience.ss"
+          (only-in "type-effect-convenience.ss" [make-arr* make-arr])
+          "union.ss"
+          string-constants/string-constant
+          (lib "match-error.ss" "mzlib" "private" "match")
+          "tc-structs.ss"))
+
+(define-for-syntax (initialize-others) 
+  (d-s date 
+       ([second : N] [minute : N] [hour : N] [day : N] [month : N] 
+        [year : N] [weekday : N] [year-day : N] [dst? : B] [time-zone-offset : N])
+       ())
+  (d-s exn ([message : -String] [continuation-marks : Univ]) ())
+  (d-s (exn:fail exn) () (-String Univ))
+  (d-s (exn:fail:read exn:fail) ([srclocs : (-lst Univ)]) (-String Univ))
+  )
+
+(provide (for-syntax initial-env initialize-others))
+
+(define-for-syntax initial-env
+  (let ([make-lst make-Listof]
+        [make-lst/elements -pair])
+    (make-env
+     
+     [string->sexpr (-> -String (-mu x (Un Sym -String N B (-lst x))))]
+     
+     (car (make-Poly (list 'a 'b) (cl-> [((-pair (-v a) (-v b))) (-v a)]
+                                        [((make-lst (-v a))) (-v a)])))
+     [first (make-Poly (list 'a 'b) (cl-> [((-pair (-v a) (-v b))) (-v a)]
+                                          [((make-lst (-v a))) (-v a)]))]
+     [second (-poly (a b c)
+                    (cl->                
+                     [((-pair a (-pair b c))) b]
+                     [((-lst a)) a]))]
+     [third (-poly (a b c d)
+                   (cl->                
+                    [((-pair a (-pair b (-pair c d)))) c]
+                    [((-lst a)) a]))]
+     [fourth (-poly (a) ((-lst a) . -> .  a))]
+     [fifth (-poly (a) ((-lst a) . -> .  a))]
+     [sixth (-poly (a) ((-lst a) . -> .  a))]
+     [rest (-poly (a) ((-lst a) . -> .  (-lst a)))]
+     (cadr 
+      (-poly (a b c)
+             (cl->                
+              [((-pair a (-pair b c))) b]
+              [((-lst a)) a])))
+     (caddr (-poly (a) (-> (-lst a) a)))
+     (cadddr (-poly (a) (-> (-lst a) a)))
+     (cdr (make-Poly (list 'a 'b) (cl-> [((-pair (-v a) (-v b))) (-v b)]
+                                        [((make-lst (-v a))) (make-lst (-v a))])))
+     (cddr (make-Poly (list 'a) (-> (make-lst (-v a)) (make-lst (-v a)))))
+     (cdddr (make-Poly (list 'a) (-> (make-lst (-v a)) (make-lst (-v a)))))
+     (cons (-poly (a b) 
+                  (cl-> [(a (-lst a)) (-lst a)]
+                        [(a b) (-pair a b)])))
+     [*cons (-poly (a b) (cl-> 
+                               [(a b) (-pair a b)]
+                               [(a (-lst a)) (-lst a)]))]
+     [*list? (make-pred-ty (-lst Univ))]
+     
+     (null? (make-pred-ty (-val null)))
+     (eof-object? (make-pred-ty (-val eof)))
+     [null (-val null)]
+     (number? (make-pred-ty N))
+     (integer? (make-pred-ty -Integer))
+     (boolean? (make-pred-ty B))
+     (add1 (-> N N))
+     (sub1 (-> N N))
+     (eq? (-> Univ Univ B))
+     (eqv? (-> Univ Univ B))
+     (equal? (-> Univ Univ B))
+     (even? (-> N B))
+     [assert (-poly (a) (-> (*Un a (-val #f)) a))]
+     [gensym (cl-> [(Sym) Sym]
+                   [() Sym])]
+     [string-append (->* null -String -String)]
+     [open-input-string (-> -String -Input-Port)]
+     [open-output-file 
+      (cl->
+       [(-Pathlike) -Port]
+       [(-Pathlike Sym) -Port])]
+     [read (cl-> 
+            [(-Port) -Sexp]
+            [() -Sexp])]
+     [ormap (-poly (a b) ((-> a b) (-lst a) . -> . b))]
+     [andmap (-poly (a b) ((-> a b) (-lst a) . -> . b))]
+     [newline (cl-> [() -Void]
+                    [(-Port) -Void])]
+     [not (-> Univ B)]
+     [floor (-> N N)]
+     [box (-poly (a) (a . -> . (make-Box a)))]
+     [unbox (-poly (a) ((make-Box a) . -> . a))]
+     [set-box! (-poly (a) ((make-Box a) a . -> . -Void))]
+     [box? (make-pred-ty (make-Box Univ))]
+     [cons? (make-pred-ty (-pair Univ Univ))]
+     [pair? (make-pred-ty (-pair Univ Univ)) #;(-poly (a b) (make-pred-ty (-pair a b)))]
+     [empty? (make-pred-ty (-val null))]
+     [empty (-val null)]
+     [string? (make-pred-ty -String)]
+     [string (->* '() -Char -String)]
+     [symbol? (make-pred-ty Sym)]
+     [list? (make-pred-ty (-lst Univ))]
+     [list (-poly (a) (->* '() a (-lst a)))]
+     [procedure? (make-pred-ty (make-Function (list (make-top-arr))))]
+     [map 
+      (-poly (a b c d)
+             (cl-> [((-> a b) (-lst a)) (-lst b)]
+                   [((-> a b c) (-lst a) (-lst b)) (-lst c)]
+                   [((-> a b c d) (-lst a) (-lst b) (-lst c)) (-lst d)]))]
+     [for-each 
+      (-poly (a b c)
+             (cl-> [((-> a b) (-lst a)) -Void]
+                   [((-> a b c) (-lst a) (-lst b)) -Void]))]
+     [foldl (-poly (a b) 
+                   ((a b . -> . b) b (make-lst a) . -> . b))]
+     
+     [call-with-values (-poly (a b) (-> (-> a) (-> a b) b))]
+     
+     (error 
+      (make-Function (list 
+                      (make-arr null (Un))
+                      (make-arr (list Sym -String) (Un) Univ)
+                      (make-arr (list -String) (Un) Univ)
+                      (make-arr (list Sym) (Un)))))
+     
+     
+     [namespace-variable-value 
+      (cl-> 
+       [(Sym) Univ]
+       [(Sym B -Namespace (-> Univ)) Univ])]
+     
+     (match:error (Univ . -> . (Un)))
+     (display 
+      (cl->
+       [(Univ) -Void]
+       [(Univ -Port) -Void]))
+     [void (->* '() Univ -Void)]
+     [void? (make-pred-ty -Void)]
+     [printf (->* (list -String) Univ -Void)]
+     [fprintf (->* (list -Output-Port -String) Univ -Void)]
+     [format (->* (list -String) Univ -String)]   
+     (fst (make-Poly (list 'a 'b) (-> (make-lst/elements (-v a) (-v b)) (-v a))))
+     (snd (make-Poly (list 'a 'b) (-> (make-lst/elements (-v a) (-v b)) (-v b))))
+     
+     (= (->* (list N N) N B))
+     (>= (->* (list N N) N B))
+     (< (->* (list N N) N B))
+     (<= (->* (list N N) N B))
+     [> (->* (list N) N B)]
+     (zero? (N . -> . B))
+     (* (->* '() N N))
+     (/ (->* (list N) N N))
+     (+ (->* '() N N))
+     (- (->* (list N) N N))
+     (max (->* (list N) N N))
+     (min (->* (list N) N N))
+     [values  (make-Poly '(a) (-> (-v a) (-v a)))]
+     [vector-ref 
+      (make-Poly (list 'a) ((make-Vector (-v a)) N . -> . (-v a)))]
+     [build-vector (-poly (a) (N (N . -> . a) . -> . (make-Vector a)))]
+     [reverse (make-Poly '(a) (-> (make-lst (-v a)) (make-lst (-v a))))]
+     [append (-poly (a) (->* (list) (-lst a) (-lst a)))]
+     [length (make-Poly '(a) (-> (make-lst (-v a)) N))]
+     [memq (make-Poly (list 'a) (-> (-v a) (make-lst (-v a)) (-opt (make-lst (-v a)))))]
+     [memv (make-Poly (list 'a) (-> (-v a) (make-lst (-v a)) (-opt (make-lst (-v a)))))]
+     [member 
+      (-poly (a) (a (-lst a) . -> . (-opt (-lst a))))]
+     
+     [string<? (->* (list -String -String) -String B)]
+     [string>? (->* (list -String -String) -String B)]
+     [string=? (->* (list -String -String) -String B)]
+     [char=? (->* (list -Char -Char) -Char B)]
+     [string<=? (->* (list -String -String) -String B)]
+     [string>=? (->* (list -String -String) -String B)]
+     
+     [string-ci<? (->* (list -String -String) -String B)]
+     [string-ci>? (->* (list -String -String) -String B)]
+     [string-ci=? (->* (list -String -String) -String B)]
+     [string-ci<=? (->* (list -String -String) -String B)]
+     [string-ci>=? (->* (list -String -String) -String B)]
+     
+     [string-upcase (-> -String -String)]
+     [string-downcase (-> -String -String)]
+     [string-titlecase (-> -String -String)]
+     [string-foldcase (-> -String -String)]
+     
+     [string-normalize-nfd (-> -String -String)]
+     [string-normalize-nfkd (-> -String -String)]
+     [string-normalize-nfc (-> -String -String)]
+     [string-normalize-nfkc (-> -String -String)]
+     
+     [string-ref (-> -String N -Char)]
+     [substring (cl->*
+                 (-> -String N -String)
+                 (-> -String N N -String))]
+     [string->path (-> -String -Path)]
+     [file-exists? (-> -Pathlike B)]
+     
+     [assq (-poly (a) (-> Univ (-lst (-pair Univ a)) a))]
+     
+     [build-path ((list -Pathlike*) -Pathlike* . ->* . -Path)]
+     [string->number (-> -String (-opt N))]
+     [with-input-from-file 
+         (-poly (a) 
+                (cl->
+                 [(-Pathlike  (-> a))  a]
+                 [(-Pathlike (-> a) Sym) a]))]
+     [with-output-to-file
+         (-poly (a) 
+                (cl->
+                 [(-Pathlike  (-> a))  a]
+                 [(-Pathlike (-> a) Sym) a]))]
+     
+     [random (cl->
+              [(N) N]
+              [() N])]
+     
+     [assoc (-poly (a b) (a (-lst (-pair a b)) . -> . (-opt (-pair a b))))]
+     
+     [list-ref (-poly (a) ((-lst a) N . -> . a))]
+     [positive? (-> N B)]
+     [negative? (-> N B)]
+     [odd? (-> N B)]
+     [even? (-> N B)]
+     
+     [apply (-poly (a b) (((list) a . ->* . b) (-lst a) . -> . b))]
+     
+     [call/cc (-poly (a b) (((a . -> . (Un)) . -> . b) . -> . (*Un a b)))]
+     [call/ec (-poly (a b) (((a . -> . (Un)) . -> . b) . -> . (*Un a b)))]
+     
+     [quotient (N N . -> . N)]
+     [remainder (N N . -> . N)]
+     [quotient/remainder (N N . -> . (-values (list N N)))]
+     
+     ;; parameter stuff
+     
+     [parameterization-key Sym]
+     [extend-parameterization (-poly (a b) (-> Univ (-Param a b) a Univ))]
+     [continuation-mark-set-first (-> (-opt -Cont-Mark-Set) Univ Univ)]
+     [make-parameter (-poly (a b) (cl-> [(a) (-Param a a)]
+                                        [(b (a . -> . b)) (-Param a b)]))]
+     [current-directory (-Param -Pathlike -Path)]
+     [current-namespace (-Param -Namespace -Namespace)]
+     [print-struct (-Param B B)]
+     [read-decimal-as-inexact (-Param B B)]
+     [current-command-line-arguments (-Param (make-Vector -String) (make-Vector -String))]
+     
+     ;; regexp stuff
+     [regexp-match 
+      (cl->
+       [((*Un -String -Regexp) -String) (-opt (-lst (-opt -String)))]
+       [(-Pattern -String) (-opt (-lst (-opt (*Un -Bytes -String))))]
+       [(-Pattern -String N) (-opt (-lst (-opt (*Un -Bytes -String))))]
+       [(-Pattern -String N (-opt N)) (-opt (-lst (-opt (*Un -Bytes -String))))]
+       [(-Pattern -String N (-opt N) (-opt -Output-Port)) (-lst (-opt (*Un -Bytes -String)))]
+       [(-Pattern -String (-opt N) (-opt -Output-Port)) (-lst (-opt (*Un -Bytes -String)))]
+       [(-Pattern -String (-opt -Output-Port)) (-lst (-opt (*Un -Bytes -String)))]
+       [(-Pattern (*Un -Input-Port -Bytes)) (-opt (-lst (-opt -Bytes)))]
+       [(-Pattern (*Un -Input-Port -Bytes) N) (-opt (-lst (-opt -Bytes)))]
+       [(-Pattern (*Un -Input-Port -Bytes) N (-opt N)) (-opt (-lst (-opt -Bytes)))]
+       [(-Pattern (*Un -Input-Port -Bytes) (-opt N)) (-opt (-lst (-opt -Bytes)))]
+       [(-Pattern (*Un -Input-Port -Bytes) N (-opt N) (-opt -Output-Port)) (-lst (-opt -Bytes))])]
+     
+     
+     [number->string (N . -> . -String)]
+     
+     [current-milliseconds (-> N)]
+     [modulo (N N . -> . N)]
+     
+     ;; errors
+     
+     [raise-type-error
+      (cl->
+       [(Sym -String Univ) (Un)]
+       [(Sym -String N (-lst Univ)) (Un)])]
+     
+     ;; this is a hack
+     
+     [match:error ((list) Univ . ->* . (Un))]
+     
+     [vector-set! (-poly (a) (-> (make-Vector a) N a -Void))]
+     
+     [vector->list (-poly (a) (-> (make-Vector a) (-lst a)))]
+     [list->vector (-poly (a) (-> (-lst a) (make-Vector a)))]
+     [exact? (N . -> . B)]
+     [inexact? (N . -> . B)]
+     [expt (N N . -> . N)]
+     [vector (-poly (a) (->* (list) a (make-Vector a)))]
+     [real? (Univ . -> . B)]
+     [real-part (N . -> . N)]
+     [imag-part (N . -> . N)]
+     [magnitude (N . -> . N)]
+     [angle (N . -> . N)]
+     [numerator (N . -> . N)]
+     [denominator (N . -> . N)]
+     [exact->inexact (N . -> . N)]
+     [inexact->exact (N . -> . N)]
+     [make-string
+      (cl->
+       [(N) -String]
+       [(N -Char) -String])]
+     [arithmetic-shift (N N . -> . N)]
+     [abs (N . -> . N)]
+     [substring (cl-> [(-String N) -String]
+                      [(-String N N) -String])]
+     [string-length (-String . -> . N)]
+     [string-set! (-String N -Char . -> . -Void)]
+     [make-vector
+      (-poly (a)
+             (cl->
+              [(N) (make-Vector N)]
+              [(N a) (make-Vector a)]))]
+     
+     [file-exists? (-Pathlike . -> . B)]
+     [string->symbol (-String . -> . Sym)]
+     [symbol->string (Sym . -> . -String)]
+     [vector-length (-poly (a) ((make-Vector a) . -> . N))]
+     
+     [call-with-input-file (-poly (a) 
+                                  (cl->
+                                   [(-String (-Port . -> . a))  a]
+                                   [(-String (-Port . -> . a) Sym)  a]))]
+     
+     [call-with-output-file (-poly (a) 
+                                   (cl->
+                                    [(-String (-Port . -> . a))  a]
+                                    [(-String (-Port . -> . a) Sym)  a]))]
+     [current-output-port (-Param -Output-Port -Output-Port)]
+     [current-error-port (-Param -Output-Port -Output-Port)]
+     [current-input-port (-Param -Input-Port -Input-Port)]
+     [round (N . -> . N)]
+     [seconds->date (N . -> . (make-Struct 'date #f (list N N N N N N N N B N) #f))]
+     [current-seconds (-> N)]
+     [sqrt (-> N N)]
+     [path->string (-> -Path -String)]       
+     
+     [link-exists? (-> -Pathlike B)]
+     [directory-exists? (-> -Pathlike B)]
+     [file-exists? (-> -Pathlike B)]
+     [directory-list (cl-> [() (-lst -Path)]
+                           [(-Path) (-lst -Path)])]
+     
+     [make-hash-table (let ([ht-opt (*Un (-val 'weak) (-val 'equal))])
+                        (-poly (a b) 
+                               (cl-> [() (-HT a b)]
+                                     [(ht-opt) (-HT a b)]
+                                     [(ht-opt ht-opt) (-HT a b)])))]
+     
+     [hash-table-put! (-poly (a b) ((-HT a b) a b . -> . -Void))]
+     [hash-table-map (-poly (a b c) ((-HT a b) (a b . -> . c) . -> . (-lst c)))]
+     [hash-table-get (-poly (a b c)
+                            (cl->
+                             (((-HT a b) a) b)
+                             (((-HT a b) a (-> c)) (*Un b c))
+                             (((-HT a b) a c) (*Un b c))))]
+     #;[hash-table-index (-poly (a b) ((-HT a b) a b . -> . -Void))]
+     
+     [bytes (->* (list) N -Bytes)]
+     [bytes-ref (-> -Bytes N N)]
+     [bytes-append (->* (list -Bytes) -Bytes -Bytes)]
+     [subbytes (cl->
+                [(-Bytes N) -Bytes]
+                [(-Bytes N N) -Bytes])]
+     [bytes-length (-> -Bytes N)]
+     [open-input-file (-> -Pathlike -Input-Port)]
+     [close-input-port (-> -Input-Port -Void)]
+     [close-output-port (-> -Output-Port -Void)]   
+     [read-line (cl->
+                 [() -String]
+                 [(-Input-Port) -String]
+                 [(-Input-Port Sym) -String])]
+     [copy-file (-> -Pathlike -Pathlike -Void)]  
+     [bytes->string/utf-8 (-> -Bytes -String)]
+     ;; language
+     [(expand #'(this-language))
+      Sym
+      string-constants/string-constant]
+     ;; make-promise 
+     
+     [(cadr (syntax->list (expand #'(delay 3)))) 
+      (-poly (a) (-> (-> a) (-Promise a)))
+      scheme/promise]
+     ;; qq-append
+     
+     [(cadr (syntax->list (expand #'`(,@'() 1)))) 
+      (-poly (a b) 
+             (cl->*
+              (-> (-lst a) (-val '()) (-lst a))
+              (-> (-lst a) (-lst b) (-lst (*Un a b)))))]
+     
+     [force (-poly (a) (-> (-Promise a) a))]
+     [bytes<? (->* (list -Bytes) -Bytes B)]
+     [regexp-replace* 
+      (cl->*
+       (-Pattern (*Un -Bytes -String) (*Un -Bytes -String) . -> . -Bytes)
+       (-Pattern -String -String . -> . -String))]
+     [peek-char
+      (cl->*
+       [-> -Char]
+       [-Input-Port . -> . -Char]
+       [-Input-Port N . -> . -Char]
+       [N . -> . -Char])]
+     [peek-byte
+      (cl->*
+       [-> -Byte]
+       [-Input-Port . -> . -Byte]
+       [-Input-Port N . -> . -Byte]
+       [N . -> . -Byte])]
+     [make-pipe
+      (cl->*
+       [-> (-values (list -Input-Port -Output-Port))]
+       [N . -> . (-values (list -Input-Port -Output-Port))])]
+     [open-output-bytes
+      (cl->*
+       [-> -Output-Port]
+       [Univ . -> . -Output-Port])]
+     [get-output-bytes
+      (cl->*
+       [-Output-Port . -> . -Bytes]
+       [-Output-Port Univ . -> . -Bytes]
+       [-Output-Port Univ N . -> . -Bytes]
+       [-Output-Port Univ N N . -> . -Bytes]
+       [-Output-Port N . -> . -Bytes]
+       [-Output-Port N N . -> . -Bytes])]
+     #;[exn:fail? (-> Univ B)]
+     #;[exn:fail:read? (-> Univ B)]
+     
+     [write (-> -Sexp -Void)]
+     [open-output-string (-> -Output-Port)]
+     ;; FIXME - wrong
+     [get-output-string (-> -Output-Port -String)]
+     
+     [make-directory (-> -Path -Void)]
+     
+     [hash-table-for-each (-poly (a b c)
+                                 (-> (-HT a b) (-> a b c) -Void))]
+     
+     [delete-file (-> -Pathlike -Void)]
+     [make-namespace (cl->* (-> -Namespace)
+                            (-> (*Un (-val 'empty) (-val 'initial)) -Namespace))]
+     [eval (-> -Sexp Univ)]
+     
+     [exit (-> (Un))]
+     
+     ;; syntax operations
+     
+     [syntax-source (-poly (a) (-> (-Syntax a) Univ))]
+     [syntax-position (-poly (a) (-> (-Syntax a) (-opt N)))]
+     [datum->syntax (cl->* 
+                     (-> (-opt (-Syntax Univ)) Sym (-Syntax Sym))
+                     (-> (-opt (-Syntax Univ)) Univ (-Syntax Univ)))]
+     [syntax->datum (-poly (a) (-> (-Syntax a) Univ))]
+     [syntax-e (-poly (a) (-> (-Syntax a) a))]
+     [syntax-original? (-poly (a) (-> (-Syntax a) B))]
+     [identifier? (make-pred-ty (-Syntax Sym))]
+     [syntax? (make-pred-ty (-Syntax Univ))]
+     [syntax-property (-poly (a) (cl->* (-> (-Syntax a) Univ Univ (-Syntax a))
+                                        (-> (-Syntax Univ) Univ Univ)))]
+     )))
+
+(begin-for-syntax (initialize-type-env initial-env)
+                  (initialize-others))
+
+;; the initial type name environment - just the base types
+(define-syntax (define-tname-env stx)
+  (syntax-case stx ()
+    [(_ var provider [nm ty] ...)
+     #`(begin
+         (define-syntax nm (lambda (stx) (raise-syntax-error 'type-check "type name used out of context" stx))) ...
+         (provide nm) ...
+         (define-syntax provider (lambda (stx) #'(begin (provide nm) ...)))
+         (provide provider)
+         (begin-for-syntax
+           (initialize-type-name-env
+            (list (list #'nm ty) ...))))]))
+
+(define-syntax (define-other-types stx)
+  (syntax-case stx ()
+    [(_ provider requirer nm ...)
+     (with-syntax ([(nms ...) (generate-temporaries #'(nm ...))])
+       (let ([body-maker (lambda (stx)
+                           (map (lambda (nm nms) (datum->syntax stx `(rename ,#'mod ,nm ,nms)))
+                                (syntax->list #'(nm ...))
+                                (syntax->list #'(nms ...))))])
+         #'(begin (define-syntax nms (lambda (stx) (raise-syntax-error 'type-check "type name used out of context" stx))) ...
+                  (provide nms) ...
+                  (define-syntax (requirer stx) 
+                    (syntax-case stx () 
+                      [(_ mod) 
+                       (datum->syntax
+                        stx
+                        `(require . ,(map (lambda (nm* nms*) (datum->syntax stx `(rename ,#'mod ,nm* ,nms*)))
+                                          (list 'nm ...)
+                                          (list #'nms ...))))]))                  
+                  (define-syntax provider (lambda (stx) #'(begin (provide (rename-out [nms nm])) ...)))
+                  (provide provider requirer))))]))
+
+;; the initial set of available type names
+(define-tname-env initial-type-names provide-tnames
+  [Number N]
+  [Integer -Integer]
+  [Void -Void]
+  [Boolean B]
+  [Symbol Sym]
+  [String -String]
+  [Any Univ]
+  [Port -Port]
+  [Path -Path]
+  [Regexp -Regexp]
+  [PRegexp -PRegexp]
+  [Char -Char]
+  [Option (-poly (a) (-opt a))]
+  [List (-lst Univ)]
+  [Listof -Listof]
+  [Namespace -Namespace]
+  [Input-Port -Input-Port]
+  [Output-Port -Output-Port]
+  [Bytes -Bytes]
+  [EOF (-val eof)]
+  [Keyword -Keyword]
+  [HashTable (-poly (a b) (-HT a b))]
+  [Promise (-poly (a) (-Promise a))]
+  [Pair (-poly (a b) (-pair a b))]
+  [Box (-poly (a) (make-Box a))]
+  [Syntax Any-Syntax]
+  [Identifier Ident]
+  )
+
+(define-other-types
+  provide-extra-tnames
+  require-extra-tnames
+  
+  
+  -> U mu Un All Opaque Vectorof
+  Parameter Tuple Class
+  )  
+
+(provide-extra-tnames)
+
diff --git a/collects/typed-scheme/private/check-subforms-unit.ss b/collects/typed-scheme/private/check-subforms-unit.ss
new file mode 100644
index 0000000000..79298be97c
--- /dev/null
+++ b/collects/typed-scheme/private/check-subforms-unit.ss
@@ -0,0 +1,110 @@
+#lang scheme/unit
+
+(require (prefix-in 1: srfi/1)
+         syntax/kerncase
+         syntax/struct
+         syntax/stx
+         mzlib/etc
+         mzlib/plt-match
+         "type-contract.ss"
+         "signatures.ss"
+         "tc-structs.ss"
+         "type-utils.ss"
+         "utils.ss" ;; doesn't need tests
+         "type-rep.ss" ;; doesn't need tests
+         "unify.ss" ;; needs tests
+         "infer.ss"
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "union.ss"
+         "subtype.ss" ;; has tests
+         "internal-forms.ss" ;; doesn't need tests
+         "planet-requires.ss" ;; doesn't need tests
+         "type-env.ss" ;; maybe needs tests
+         "parse-type.ss" ;; has tests
+         "tc-utils.ss" ;; doesn't need tests
+         "type-environments.ss" ;; doesn't need tests
+         "lexical-env.ss" ;; maybe needs tests
+         "type-annotation.ss" ;; has tests
+         "type-name-env.ss" ;; maybe needs tests
+         "init-envs.ss"
+         "effect-rep.ss"
+         "mutated-vars.ss")
+
+(import tc-if^ tc-lambda^ tc-app^ tc-let^ tc-expr^)
+(export check-subforms^)
+
+;; find the subexpressions that need to be typechecked in an ignored form
+;; syntax -> void
+(define (check-subforms/with-handlers form)
+  (define handler-tys '())
+  (define body-ty #f)    
+  (define (get-result-ty t)
+    (match t
+      [(Function: (list (arr: _ rngs _ _ _) ...)) (apply Un rngs)]
+      [_ (tc-error "Internal error in get-result-ty: not a function type: ~n~a" t)]))
+  (let loop ([form form])
+    (parameterize ([current-orig-stx form])
+      (kernel-syntax-case* form #f (#%app)
+        [stx
+         ;; if this needs to be checked
+         (syntax-property form 'typechecker:with-type)
+         ;; the form should be already ascribed the relevant type
+         (void 
+          (tc-expr form))]
+        [stx
+         ;; this is a hander function
+         (syntax-property form 'typechecker:exn-handler)
+         (let ([t (tc-expr/t form)])
+           (unless (subtype t (-> (Un) Univ))
+             (tc-error "Exception handler must be a single-argument function, got ~n~a"))
+           (set! handler-tys (cons (get-result-ty t) handler-tys)))]
+        [stx
+         ;; this is the body of the with-handlers
+         (syntax-property form 'typechecker:exn-body)
+         (let ([t (tc-expr/t form)])
+           (set! body-ty t))]
+        [(a . b)
+         (begin
+           (loop #'a)
+           (loop #'b))]
+        [_ (void)])))
+  (ret (apply Un body-ty handler-tys)))
+
+(define (check-subforms/with-handlers/check form expected)
+  (let loop ([form form])
+    (parameterize ([current-orig-stx form])
+      (kernel-syntax-case* form #f ()
+        [stx
+         ;; if this needs to be checked
+         (syntax-property form 'typechecker:with-type)
+         ;; the form should be already ascribed the relevant type
+         (tc-expr form)]
+        [stx
+         ;; this is a hander function
+         (syntax-property form 'typechecker:exn-handler)
+         (tc-expr/check form (-> (Un) expected))]
+        [stx
+         ;; this is the body of the with-handlers
+         (syntax-property form 'typechecker:exn-body)
+         (tc-expr/check form expected)]
+        [(a . b)
+         (begin
+           (loop #'a)
+           (loop #'b))]
+        [_ (void)])))
+  expected)
+
+;; typecheck the expansion of a with-handlers form
+;; syntax -> type
+(define (check-subforms/ignore form)
+  (let loop ([form form])
+    (kernel-syntax-case* form #f ()
+      [stx
+       ;; if this needs to be checked
+       (syntax-property form 'typechecker:with-type)
+       ;; the form should be already ascribed the relevant type
+       (tc-expr form)]
+      [(a . b)
+       (loop #'a)
+       (loop #'b)]
+      [_ (void)])))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/def-binding.ss b/collects/typed-scheme/private/def-binding.ss
new file mode 100644
index 0000000000..41d3136105
--- /dev/null
+++ b/collects/typed-scheme/private/def-binding.ss
@@ -0,0 +1,10 @@
+#lang scheme/base
+
+
+(provide (struct-out binding)
+         (struct-out def-binding)
+         (struct-out def-stx-binding))
+
+(define-struct binding (name) #:inspector #f)
+(define-struct (def-binding binding) (ty) #:inspector #f)
+(define-struct (def-stx-binding binding) () #:inspector #f)
\ No newline at end of file
diff --git a/collects/typed-scheme/private/defstruct-unit.ss b/collects/typed-scheme/private/defstruct-unit.ss
new file mode 100644
index 0000000000..fa4e6b29de
--- /dev/null
+++ b/collects/typed-scheme/private/defstruct-unit.ss
@@ -0,0 +1,22 @@
+(module defstruct-unit mzscheme
+  (require (lib "struct.ss") (lib "unit.ss"))
+  (provide (all-defined))
+  
+  (define-syntax defstructs/sig/unit
+    (syntax-rules (define-struct/properties)
+      [(_ signame unitname (imps ...)
+          def
+          (define-struct/properties nm1 (flds1 ...) props #f)
+          (define-struct/properties (nm par) (flds ...) () #f) ...)
+       (begin
+         (define-signature signame
+           ((struct nm1 (flds1 ...))
+            (struct nm (flds ...)) ...))
+         (define-unit unitname           
+           (import imps ...)
+           (export signame)
+           def
+           (define-struct/properties nm1 (flds1 ...) props #f)
+           (define-struct (nm par) (flds ...) #f) ...))]))
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/effect-rep.ss b/collects/typed-scheme/private/effect-rep.ss
new file mode 100644
index 0000000000..e33977f9b6
--- /dev/null
+++ b/collects/typed-scheme/private/effect-rep.ss
@@ -0,0 +1,39 @@
+#lang scheme/base
+
+(require (lib "plt-match.ss"))
+(require (lib "etc.ss"))
+(require "rep-utils.ss" "free-variance.ss")
+
+(de True-Effect () [#:frees #f] [#:fold-rhs #:base])
+
+(de False-Effect () [#:frees #f] [#:fold-rhs #:base])
+
+;; v is an identifier
+(de Var-True-Effect (v) [#:intern (hash-id v)] [#:frees #f] [#:fold-rhs #:base])
+
+;; v is an identifier
+(de Var-False-Effect (v) [#:intern (hash-id v)] [#:frees #f] [#:fold-rhs #:base])
+
+;; t is a Type
+;; v is an identifier
+(de Restrict-Effect (t v) [#:intern (list t (hash-id v))] [#:frees (free-vars* t) (free-idxs* t)]
+    [#:fold-rhs (*Restrict-Effect (type-rec-id t) v)])
+
+;; t is a Type
+;; v is an identifier
+(de Remove-Effect (t v) 
+    [#:intern (list t (hash-id v))]
+    [#:frees (free-vars* t) (free-idxs* t)]
+    [#:fold-rhs (*Remove-Effect (type-rec-id t) v)])
+
+;; t is a Type
+(de Latent-Restrict-Effect (t))
+
+;; t is a Type
+(de Latent-Remove-Effect (t))
+
+(de Latent-Var-True-Effect () [#:frees #f] [#:fold-rhs #:base])
+
+(de Latent-Var-False-Effect () [#:frees #f] [#:fold-rhs #:base])
+
+;; could also have latent true/false effects, but seems pointless
diff --git a/collects/typed-scheme/private/extra-procs.ss b/collects/typed-scheme/private/extra-procs.ss
new file mode 100644
index 0000000000..cd8af3b267
--- /dev/null
+++ b/collects/typed-scheme/private/extra-procs.ss
@@ -0,0 +1,9 @@
+(module extra-procs mzscheme  
+  (provide assert)    
+  
+  (define (assert v)
+    (unless v
+      (error "Assertion failed - value was #f"))
+    v)
+
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/free-variance.ss b/collects/typed-scheme/private/free-variance.ss
new file mode 100644
index 0000000000..8bf8664d06
--- /dev/null
+++ b/collects/typed-scheme/private/free-variance.ss
@@ -0,0 +1,98 @@
+#lang scheme/base
+
+(require (for-syntax scheme/base)
+         mzlib/etc)
+
+;; this file contains support for calculating the free variables/indexes of types
+;; actual computation is done in rep-utils.ss  and type-rep.ss
+
+(define-values (Covariant Contravariant Invariant Constant)
+  (let ()
+    (define-struct Variance () #:inspector #f)
+    (define-struct (Covariant Variance) () #:inspector #f)
+    (define-struct (Contravariant Variance) () #:inspector #f)
+    (define-struct (Invariant Variance) () #:inspector #f)
+    (define-struct (Constant Variance) () #:inspector #f)
+    (values (make-Covariant) (make-Contravariant) (make-Invariant) (make-Constant))))
+
+
+(provide Covariant Contravariant Invariant Constant)
+
+;; hashtables for keeping track of free variables and indexes
+(define index-table (make-hash-table 'weak))
+;; maps Type to List[Cons[Number,Variance]]
+(define var-table (make-hash-table 'weak))
+;; maps Type to List[Cons[Symbol,Variance]]
+
+(define (free-idxs* t) (hash-table-get index-table t (lambda _ (error "type not in index-table" (syntax-e t)))))
+(define (free-vars* t) (hash-table-get var-table t (lambda _ (error "type not in var-table" (syntax-e t)))))
+
+
+(define empty-hash-table (make-immutable-hash-table null))
+
+(provide free-vars* free-idxs* empty-hash-table make-invariant)
+
+;; frees = HT[Idx,Variance] where Idx is either Symbol or Number
+;; (listof frees) -> frees
+(define (combine-frees freess)    
+  (define ht (make-hash-table))
+  (define (combine-var v w)
+    (cond
+      [(eq? v w) v]
+      [(eq? v Constant) w]
+      [(eq? w Constant) v]
+      [else Invariant]))
+  (for-each
+   (lambda (old-ht)
+     (hash-table-for-each 
+      old-ht
+      (lambda (sym var)
+        (let* ([sym-var (hash-table-get ht sym (lambda () #f))])
+          (if sym-var
+              (hash-table-put! ht sym (combine-var var sym-var))
+              (hash-table-put! ht sym var))))))
+   freess)
+  ht)
+
+;; frees -> frees
+(define (flip-variances vs)
+  (hash-table-map* 
+   (lambda (k v) 
+     (evcase 
+         v
+       [Covariant Contravariant]
+       [Contravariant Covariant]
+       [v v]))
+   vs))
+
+(define (make-invariant vs)
+  (hash-table-map* 
+   (lambda (k v) Invariant)
+   vs))
+
+(define (hash-table-map* f ht)
+  (define new-ht (hash-table-copy ht))
+  (hash-table-for-each 
+   new-ht
+   (lambda (k v)
+     (hash-table-put! 
+      new-ht
+      k
+      (f k v))))
+  new-ht)
+
+(define (without-below n frees)
+  (define new-ht (hash-table-copy frees))
+  (hash-table-for-each 
+   new-ht
+   (lambda (k v)
+     (when (< k n) (hash-table-remove! new-ht k))))
+  new-ht)
+
+(provide combine-frees flip-variances without-below unless-in-table var-table index-table empty-hash-table)
+
+(define-syntax (unless-in-table stx) 
+  (syntax-case stx ()
+    [(_ table val . body)
+     (quasisyntax/loc stx
+       (hash-table-get table val #,(syntax/loc #'body (lambda () . body))))]))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/infer.ss b/collects/typed-scheme/private/infer.ss
new file mode 100644
index 0000000000..c1f1c6f407
--- /dev/null
+++ b/collects/typed-scheme/private/infer.ss
@@ -0,0 +1,410 @@
+#lang scheme/base
+
+(require "unify.ss" "type-comparison.ss" "type-rep.ss" "effect-rep.ss" "subtype.ss"
+         "planet-requires.ss" "tc-utils.ss" "union.ss"
+         "resolve-type.ss"
+         "type-effect-convenience.ss"
+         (lib "trace.ss")
+         (lib "plt-match.ss")
+         (lib "list.ss"))
+(require (galore))
+
+(provide infer infer/list infer/list/vararg combine table:un exn:infer?)
+
+;; exn representing failure of inference
+;; s,t both types
+#;
+(define-struct (exn:infer exn:fail) (s t))
+
+(define-values (fail-sym exn:infer?)
+  (let ([sym (gensym)])
+    (values sym (lambda (s) (eq? s sym)))))
+
+;; inference failure - masked before it gets to the user program
+(define-syntax fail!
+  (syntax-rules ()
+    [(_ s t) (raise fail-sym)
+             #;(raise (make-exn:infer "inference failed" (current-continuation-marks) s t))
+             #;(error "inference failed" s t)]))
+
+;; conveneice function
+(define (alist->mapping vars) (table:alist->eq (map (lambda (x) (cons x 'fail)) vars)))
+
+;; flag is one of: 'co, 'contra, 'both, #f
+
+;; Mapping is a table that maps symbols to Results
+
+;; A Result is one of:
+;; - 'fail (not yet filled in)
+;; - #f (not a variable we're concerned with)
+;; - (list flag type)
+;; 
+
+;; s, t : Type
+;; vars : Listof[Symbol]
+;; produces a substitution for vars, or #f
+;; the substitution makes s a supertype of t
+;; only vars will be substituted, regardless of other free vars
+(define ((mk-infer f) s t vars)
+  (let ([mapping (alist->mapping vars)])
+    (with-handlers
+        ([exn:infer? (lambda _ #f)])
+      (mapping->subst (f s t mapping 'co)))))
+
+;; table[symbol, (list flag type)] -> substitution
+;; convert a mapping to a substitution
+(define (mapping->subst x) 
+  (define sexp (table:to-sexp x))    
+  (define result (filter (lambda (x) (list? (cadr x))) sexp))    
+  ;(printf "sexp: ~a~n" sexp)
+  (map (lambda (x) (list (car x) (cadr (cadr x)))) result))
+
+;(trace mapping->subst)
+
+;; least upper bound of two flags
+;; the lattice is like this:
+;;         'both
+;;        /      \
+;;     'co      'contra
+;;        \      /
+;;           #f
+(define (lub a b)
+  (match (list a b)
+    [(list x  x)  x]
+    [(list #f x)  x]
+    [(list x  #f) x]
+    [(list 'both x) 'both]
+    [(list x 'both) 'both]
+    [(list x y) 'both]))
+
+;; combine: flag -> Result Result -> Result
+;; combine two results into one
+(define ((combine flag*) s t)
+  (define (type-lub s t)
+    (cond [(subtype s t) t]
+          [(subtype t s) s]
+          [else (Un s t)]))
+  (define (type-glb s t)
+    (cond [(subtype s t) s]
+          [(subtype t s) t]
+          [else (fail! s t)]))
+  (define (go flag s t)
+    (cond [(and (eq? flag 'both) (type-equal? s t)) s]
+          [(eq? flag 'both) (fail! s t)]
+          [(eq? flag 'co) (type-lub s t)]
+          [(eq? flag 'contra) (type-glb s t)]
+          [(eq? flag #f) (go flag* s t)]
+          [else (int-err "bad flag value ~a" flag)]))
+  (match (list s t)
+    [(list 'fail t) t]
+    [(list t 'fail) t]
+    [(list (list sf s) (list tf t))
+     (let* ([flag (lub flag* (lub sf tf))]
+            [new-ty (go flag s t)])
+       (list flag new-ty))]))
+       #;
+     
+     ;(printf "flags : ~a ~a~n" sf tf)
+     (cond 
+       [(and sf tf (type-equal? s t)) (list (if (eq? sf tf) sf 'both) s)] ;; equal is fine
+       [(memq 'both (list sf tf)) (fail! s t)] ;; not equal, needed to be
+       [(and sf tf (not (eq? sf tf))) (fail! s t)] ;; not equal, needed to be
+       [else
+        (let ([flag (or sf tf flag)])
+          (printf "flag is ~a~n" flag)
+          (cond 
+            [(eq? 'co flag) (list 'co (Un s t))]
+            [(and (eq? 'contra flag) (subtype s t)) (list 'contra s)]
+            [(and (eq? 'contra flag) (subtype t s)) (list 'contra t)]
+            [else (fail! s t)]))])
+
+
+;(trace combine)
+
+;; combine two tables
+;; table:un : flag -> Mapping Mapping -> Mapping
+(define ((table:un flag) a b) (table:union/value a b (combine flag)))
+
+;; infer/int/union : Listof[Type] Listof[Type] Mapping Flag -> Mapping
+;; ss and ts represent unions of types
+(define (infer/int/union ss ts mapping flag)
+  (unless (= (length ss) (length ts))
+    (fail! ss ts))
+  ;; first, we remove common elements of ss and ts
+  (let-values ([(ss* ts*)
+                (values (filter (lambda (se) (not (memq se ts))) ss)
+                        (filter (lambda (te) (not (memq te ss))) ts))])
+    ;; we need to try all the pairwise possibilites
+    (let ([l (map (lambda (x y) (infer/int x y mapping flag)) ss* ts*)])
+      (foldl (table:un flag) (table:make-eq) l))))
+
+;; infer/int/list : Listof[Type] Listof[Type] Mapping Flag -> Mapping
+(define (infer/int/list ss ts mapping flag)
+  (unless (= (length ss) (length ts))
+    (fail! ss ts))
+  (let ([l (map (lambda (x y) (infer/int x y mapping flag)) ss ts)])
+    (foldl (table:un flag) (table:make-eq) l)))
+
+;; infer/int/list/eff : Listof[Effect] Listof[Effect] Mapping Flag -> Mapping
+(define (infer/int/list/eff ss ts mapping flag)
+  (cond [(or (null? ss) (null? ts)) mapping]        
+        [(not (= (length ss) (length ts)))
+         ;(error 'bad "~a ~a" ss ts)
+         (fail! ss ts)]
+        [else (let ([l (map (lambda (x y) (infer/int/eff x y mapping flag)) ss ts)])
+                (foldl (table:un flag) (table:make-eq) l))]))
+
+
+;; infer/int/list/vararg : Listof[Type] Type Listof[Type] Mapping Flag Boolean -> Mapping
+(define (infer/int/list/vararg ss rest ts mapping flag [direction #t])
+  (unless (<= (length ss) (length ts))
+    (printf "failing!~n")
+    (fail! ss ts))
+  (let loop-types
+    ([ss ss]
+     [ts ts]
+     [tbl mapping])
+    (define (ii a b)
+      (if direction
+          (infer/int a b tbl flag)
+          (infer/int b a tbl flag)))
+    (cond [(null? ts) tbl]
+          [(and rest (null? ss))
+           (let ([tbl* (ii rest (car ts))])
+             (loop-types ss (cdr ts) tbl*))]
+          [else 
+           (let ([tbl* (ii (car ss) (car ts))])
+             (loop-types (cdr ss) (cdr ts) tbl*))])))
+
+(define (infer/list/vararg ss rest ts vars)
+  (let ([mapping (alist->mapping vars)])
+    (with-handlers
+        ([exn:infer? (lambda _ #f)])
+      (mapping->subst (infer/int/list/vararg ss rest ts mapping 'co)))))
+
+
+;; Flag -> Flag
+(define (swap flag) (case flag
+                      [(co) 'contra]
+                      [(contra) 'co]
+                      [(both) 'both]
+                      [(start) 'start]
+                      [else (int-err "bad flag: ~a" flag)]))
+
+(define (co? x) (eq? x 'co))
+(define (contra? x) (eq? x 'contra))
+
+(define (infer/int/eff s t mapping flag)
+  (let ([fail! (case-lambda [() (fail! s t)]
+                            [(s t) (fail! s t)])])
+    (parameterize ([match-equality-test type-equal?])
+      (match (list s t)
+        [(list t t) mapping]
+        [(list (Latent-Restrict-Effect: t1) (Latent-Restrict-Effect: t2)) (infer/int t1 t2 mapping flag)]
+        [(list (Latent-Remove-Effect: t1) (Latent-Remove-Effect: t2)) (infer/int t1 t2 mapping flag)]
+        ))))
+
+;(trace fail!)
+
+;; type type mapping -> mapping
+(define (infer/int s t mapping flag)
+  (let ([fail! (case-lambda [() (fail! s t)]
+                            [(s t) (fail! s t)])])
+    (define (i/i s t) (infer/int s t mapping flag))
+    (parameterize ([match-equality-test type-equal?])
+      (match (list s t)
+        [(list t t) mapping]
+        [(list (F: v) t)
+         (let ([cur (table:lookup v mapping)])
+           (match cur
+             ;; we haven't yet seen this variable
+             ['fail 
+              (cond [(and (eq? flag 'contra) (type-equal? Univ t)) mapping]
+                    [(and (eq? flag 'co) (type-equal? (Un) t)) mapping]
+                    [else 
+                     (table:insert v (list #f t) mapping)])]
+             ;; we are ignoring this variable, but they weren't the same
+             [#f (fail!)]
+             ;; this variable has already been unified
+             [(list cur-flag cur-t)
+              (cond
+                [(or (not cur-flag) (eq? flag cur-flag))
+                 ;; this variable has only been handled once, or
+                 ;; we're still going in the correct direction
+                 (cond
+                   ;; this is the same type we've already seen, so don't change the flag
+                   [(type-equal? cur-t t) mapping]
+                   ;; this is a supertype of what's been found before
+                   [(and (eq? flag 'co) (subtype cur-t t)) 
+                    (table:insert v (list flag t) mapping)] 
+                   ;; this is a subtype of what's been found before
+                   [(and (eq? flag 'co) (subtype t cur-t))
+                    (table:insert v (list flag cur-t) mapping)]
+                   [(eq? flag 'co)
+                    (table:insert v (list flag (Un t cur-t)) mapping)]
+                   ;; this is a subtype of what we found before
+                   [(and (eq? flag 'contra) (subtype t cur-t))  
+                    (table:insert v (list flag t) mapping)]
+                   ;; this is a supertype of what we found before
+                   [(and (eq? flag 'contra) (subtype t cur-t))
+                    (table:insert v (list flag cur-t) mapping)]
+                   [(and (eq? flag 'both) (subtype t cur-t) (subtype cur-t t))
+                    mapping]
+                   [(eq? flag 'both)
+                    (fail! cur-t t)]
+                   ;; impossible
+                   [else (int-err "bad flag value: ~a" flag)])]
+                ;; we've switched directions at least once
+                [(type-equal? cur-t t) 
+                 ;; we're still ok
+                 (table:insert (list 'both cur-t) mapping)]
+                [else
+                 ;; we're not ok
+                 (fail! cur-t t)])]))]
+        ;; names are compared for equality
+        [(list (Name: n) (Name: n*))
+         (if (free-identifier=? n n*)
+             mapping
+             (fail!))]
+        ;; type application          
+        [(list (App: (Name: n) args _)
+               (App: (Name: n*) args* _))
+         (unless (free-identifier=? n n*)
+           (fail!))
+         (infer/int/list args args* mapping flag)]
+        ;; vectors and boxes just recur, but are invariant
+        [(list (Vector: s) (Vector: t)) (infer/int s t mapping 'both)]
+        [(list (Box: s) (Box: t)) (infer/int s t mapping 'both)]
+        ;; pairs just recur
+        [(list (Pair: s1 s2) (Pair: t1 t2))
+         (infer/int/list (list s1 s2) (list t1 t2) mapping flag)]
+        ;; ht just recur
+        [(list (Hashtable: s1 s2) (Hashtable: t1 t2))
+         (infer/int/list (list s1 s2) (list t1 t2) mapping 'both)]
+        [(list (Syntax: s1) (Syntax: s2))
+         (infer/int s1 s2 mapping flag)]
+        ;; structs just recur
+        [(list (Struct: nm p flds proc) (Struct: nm p flds* proc*))
+         (cond [(and proc proc*)
+                (infer/int/list (cons proc flds) (cons proc* flds*) mapping flag)]
+               [(or proc proc*)
+                (fail!)]
+               [else (infer/int/list flds flds* mapping flag)])]
+        ;; parameters just recur
+        [(list (Param: in1 out1) (Param: in2 out2))
+         (infer/int/list (list in1 out1) (list in2 out2) mapping flag)]
+        ;; if we have two mu's, we rename them to have the same variable
+        ;; and then compare the bodies
+        [(list (Mu-unsafe: s) (Mu-unsafe: t)) 
+         (infer/int s t mapping flag)]
+        ;; other mu's just get unfolded
+        [(list s (? Mu? t)) (infer/int s (unfold t) mapping flag)]
+        [(list (? Mu? s) t) (infer/int (unfold s) t mapping flag)]
+        ;; two unions with the same number of elements, so we just try to unify them pairwise
+        [(list (Union: l1) (Union: l2)) 
+         (=> unmatch)
+         (unless (= (length l1) (length l2))
+           (unmatch))
+         (infer/int/union l1 l2 mapping flag)]
+        
+        ;; new impl for functions
+        [(list (Function: (list t-arr ...))
+               (Function: (list s-arr ...)))
+         (=> unmatch)
+         (let loop ([t-arr t-arr] [s-arr s-arr] [mapping mapping])
+           (define (U a b) ((table:un flag) a b))
+           (define (unmatch!) (unmatch))
+           (cond [(and (null? t-arr) (null? s-arr)) mapping]
+                 [(or (null? t-arr) (null? s-arr)) (unmatch!)]
+                 [else (match (list (car t-arr) (car s-arr))
+                         [(list (arr: ts t t-rest t-thn-eff t-els-eff) (arr: ss s s-rest s-thn-eff s-els-eff))
+                          (let ([arg-mapping 
+                                 (cond [(and t-rest s-rest (= (length ts) (length ss)))
+                                        (infer/int/list (cons t-rest ts) (cons s-rest ss) mapping (swap flag))]
+                                       [(and (not t-rest) (not s-rest) (= (length ts) (length ss)))
+                                        (infer/int/list ts ss mapping (swap flag))]
+                                       [(and t-rest (not s-rest) (<= (length ts) (length ss)))
+                                        (infer/int/list/vararg ts t-rest ss mapping (swap flag) #t)]
+                                       [(and s-rest (not t-rest) (>= (length ts) (length ss)))
+                                        (infer/int/list/vararg ss s-rest ts mapping (swap flag) #f)]
+                                       [else (unmatch!)])]
+                                [ret-mapping (infer/int t s mapping flag)]
+                                [thn-mapping (infer/int/list/eff t-thn-eff s-thn-eff mapping flag)]
+                                [els-mapping (infer/int/list/eff t-els-eff s-els-eff mapping flag)])
+                            (loop (cdr t-arr) (cdr s-arr)
+                                  (U mapping (U (U arg-mapping ret-mapping) (U thn-mapping els-mapping)))))])]))]
+        ;; arrow types - just add a whole bunch of new constraints
+        [(list (Function: (list (arr: ts t t-rest t-thn-eff t-els-eff) ...))
+               (Function: (list (arr: ss s s-rest s-thn-eff s-els-eff) ...)))
+         (=> unmatch)
+         (define (compatible-rest t-rest s-rest)
+           (andmap (lambda (x y) (or (and x y) (and (not x) (not y)))) ;; either both #f or both not #f
+                   t-rest s-rest))
+         (define (U a b) ((table:un flag) a b))
+         (let-values ([(s-thn-eff s-els-eff) (if (and (null? (car t-thn-eff)) (null? (cdr t-thn-eff))
+                                                      (null? (car t-els-eff)) (null? (cdr t-els-eff)))
+                                                 (values (list null) (list null))
+                                                 (values s-thn-eff s-els-eff))])
+           (unless (and (= (length ts) (length ss))
+                        (= (length t-thn-eff) (length s-thn-eff))
+                        (= (length t-els-eff) (length s-els-eff))
+                        (compatible-rest t-rest s-rest))
+             (unmatch))
+           (let ([arg-mapping (infer/int/list (apply append ts) (apply append ss) mapping (swap flag))]
+                 [ret-mapping (infer/int/list t s mapping flag)]
+                 [thn-mapping (infer/int/list/eff (apply append t-thn-eff) (apply append s-thn-eff) mapping flag)]
+                 [els-mapping (infer/int/list/eff (apply append t-els-eff) (apply append s-els-eff) mapping flag)])             
+             (U (U arg-mapping ret-mapping) (U thn-mapping els-mapping))))]
+        ;; here, we try to handle a case-lambda as the argument to a polymorphic function
+        [(list (Function: ftys) (and t (Function: (list (arr: ss s s-rest s-thn-eff s-els-eff)))))
+         (=> unmatch)
+         (when (= 1 (length ftys)) (unmatch)) ;; we should have handled this case already
+         (or 
+          (ormap
+           (lambda (fty)
+             (with-handlers
+                 ([exn:infer? (lambda _ #f)])
+               (infer/int (make-Function (list fty)) t mapping flag)))
+           ftys)
+          (fail!))]
+        [(list (and t (Function: (list (arr: ss s s-rest s-thn-eff s-els-eff)))) (Function: ftys))
+         (=> unmatch)          
+         (when (= 1 (length ftys))  (unmatch)) ;; we should have handled this case already
+         (or 
+          (ormap
+           (lambda (fty)
+             (with-handlers
+                 ([exn:infer? (lambda _ #f)])
+               (infer/int t (make-Function (list fty)) mapping flag)))
+           ftys)
+          (fail!))]
+        ;; if t is a union, all of the elements have to match
+        [(list s (Union: e1))
+         (infer/int/list (map (lambda (_) s) e1) e1 mapping flag)]
+        ;; if s is a union, we can just try to find one of its elements that works
+        [(list (Union: e1) t) 
+         (or 
+          (ormap
+           (lambda (e)
+             (with-handlers
+                 ([exn:infer? (lambda _ #f)])
+               (infer/int e t mapping flag)))
+           e1)
+          (fail!))]
+        ;; otherwise, if we have a {sub,super}type, we're all good
+        [else (cond [(and (co? flag) (subtype t s)) mapping]
+                    [(and (contra? flag) (subtype s t)) mapping]
+                    ;; or, nothing worked, and we fail
+                    [else (fail!)])]
+        ))))
+
+;; infer: Type Type List[Symbol] -> Substitution
+(define infer (mk-infer infer/int))
+;; infer/list: Listof[Type] Listof[Type] List[Symbol] -> Substitution
+(define infer/list (mk-infer infer/int/list))
+
+;(trace infer infer/int/list infer/int infer/list)
+
+
+
+
diff --git a/collects/typed-scheme/private/init-envs.ss b/collects/typed-scheme/private/init-envs.ss
new file mode 100644
index 0000000000..957efd1ae0
--- /dev/null
+++ b/collects/typed-scheme/private/init-envs.ss
@@ -0,0 +1,78 @@
+(module init-envs mzscheme
+  (provide (all-defined))
+  
+  (require "type-env.ss" "type-rep.ss" "type-name-env.ss" "union.ss" "effect-rep.ss" (lib "shared.ss")
+           "type-effect-convenience.ss" "type-alias-env.ss"
+           "type-alias-env.ss")
+  (require (lib "pconvert.ss") (lib "plt-match.ss") (lib "list.ss"))
+  (require-for-template (lib "pconvert.ss"))
+  (require-for-template (lib "shared.ss"))
+  (require-for-template mzscheme "type-rep.ss" "union.ss" "effect-rep.ss" (lib "shared.ss"))    
+  
+  (define (initialize-type-name-env initial-type-names)
+    (for-each (lambda (nm/ty) (register-resolved-type-alias (car nm/ty) (cadr nm/ty))) initial-type-names))
+
+  (define (initialize-type-env initial-env)
+    (for-each (lambda (nm/ty) (register-type (car nm/ty) (cadr nm/ty))) initial-env))
+ 
+  (define (converter v basic sub)
+    (define (gen-constructor sym)
+      (string->symbol (string-append "make-" (substring (symbol->string sym) 7))))
+    (match v
+      [(Union: elems) `(make-Union (list ,@(map sub elems)))]
+      [(Name: stx) `(make-Name (quote-syntax ,stx))]
+      [(App: rator rands stx) `(make-App ,(sub rator) ,(sub rands) (quote-syntax ,stx))]
+      [(Opaque: pred cert) `(make-Opaque (quote-syntax ,pred) (syntax-local-certifier))]
+      [(Mu-name: n b) `(make-Mu ,(sub n) ,(sub b))]
+      [(Poly-names: ns b) `(make-Poly (list ,@(map sub ns)) ,(sub b))]
+      [(? Type? (app (lambda (v) (vector->list (struct->vector v))) (list-rest tag seq vals))) 
+       `(,(gen-constructor tag) ,@(map sub vals))]
+      [(? Effect? (app (lambda (v) (vector->list (struct->vector v))) (list-rest tag seq vals))) 
+       `(,(gen-constructor tag) ,@(map sub vals))]
+      [_ (basic v)]))
+  
+  (define (bound-in-this-module id) 
+      (let ([binding (identifier-binding id)])
+        (if (and (list? binding) (module-path-index? (car binding)))
+            (let-values ([(mp base) (module-path-index-split (car binding))])
+              (not mp))
+            #f)))
+  
+  (define (tname-env-init-code)    
+    (define (f id ty)
+        (if (bound-in-this-module id)
+            #`(register-type-name #'#,id #,(datum->syntax-object #'here (print-convert ty)))
+            #f))
+    (parameterize ((current-print-convert-hook converter)
+                   (show-sharing #f)
+                   (booleans-as-true/false #f))                   
+      (with-syntax ([registers (filter (lambda (x) x) (type-name-env-map f))])
+        #'(begin (begin-for-syntax  . registers)))))
+  
+  (define (talias-env-init-code)    
+    (define (f id ty)
+        (if (bound-in-this-module id)
+            #`(register-resolved-type-alias #'#,id #,(datum->syntax-object #'here (print-convert ty)))
+            #f))
+    (parameterize ((current-print-convert-hook converter)
+                   (show-sharing #f)
+                   (booleans-as-true/false #f))                   
+      (with-syntax ([registers (filter (lambda (x) x) (type-alias-env-map f))])
+        #'(begin (begin-for-syntax  . registers)))))
+  
+  (define (env-init-code)    
+    (define (f id ty)
+        (if (bound-in-this-module id)
+            #`(register-type #'#,id #,(datum->syntax-object #'here (print-convert ty)))
+            #f))
+    (parameterize ((current-print-convert-hook converter)
+                   (show-sharing #f)
+                   (booleans-as-true/false #f))                   
+      (with-syntax ([registers (filter (lambda (x) x) (type-env-map f))])
+        #'(begin (begin-for-syntax  . registers)))))
+
+
+
+
+
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/internal-forms.ss b/collects/typed-scheme/private/internal-forms.ss
new file mode 100644
index 0000000000..b1808af506
--- /dev/null
+++ b/collects/typed-scheme/private/internal-forms.ss
@@ -0,0 +1,15 @@
+(module internal-forms mzscheme
+  
+  (define-syntax internal-forms
+    (syntax-rules ()
+      [(_ nms ...)
+       (begin
+         (provide nms ...)
+         (define-syntax (nms stx) (raise-syntax-error 'typecheck "Internal typechecker form used out of context" stx)) ...)]))
+  
+  (internal-forms require/typed-internal define-type-alias-internal
+                  define-typed-struct-internal
+                  define-typed-struct/exec-internal
+                  assert-predicate-internal
+                  :-internal)
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/interning.ss b/collects/typed-scheme/private/interning.ss
new file mode 100644
index 0000000000..130a46a874
--- /dev/null
+++ b/collects/typed-scheme/private/interning.ss
@@ -0,0 +1,50 @@
+#lang scheme/base
+
+(require syntax/boundmap)
+
+(provide defintern hash-id)
+
+
+(define-syntax defintern
+  (syntax-rules ()
+    [(_ name+args make-name key) 
+     (defintern name+args (lambda () (make-hash-table #;'weak 'equal)) make-name key)]
+    [(_ (*name arg ...) make-ht make-name key-expr)
+     (define *name
+       (let ([table (make-ht)])
+         (lambda (arg ...)
+           #;(all-count!)
+           (let ([key key-expr])
+             (hash-table-get table key
+                             (lambda ()
+                               (let ([new (make-name (count!) arg ...)])
+                                 (hash-table-put! table key new)
+                                 new)))))))]))
+
+(define (make-count!)
+  
+  (let ([state 0])
+    (lambda () (begin0 state (set! state (add1 state)))))   
+  #;
+  (let ([ch (make-channel)])
+    (thread (lambda () (let loop ([n 0]) (channel-put ch n) (loop (add1 n)))))
+    (lambda () (channel-get ch))))
+
+(provide #;count! #;all-count! union-count!)
+
+(define count! (make-count!))
+(define union-count! (make-count!))
+(define all-count! (make-count!))
+(define id-count! (make-count!))
+
+
+
+(define identifier-table (make-module-identifier-mapping))
+
+(define (hash-id id)
+  (module-identifier-mapping-get 
+   identifier-table 
+   id 
+   (lambda () (let ([c (id-count!)])
+                (module-identifier-mapping-put! identifier-table id c)
+                c))))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/lexical-env.ss b/collects/typed-scheme/private/lexical-env.ss
new file mode 100644
index 0000000000..ffea848ebb
--- /dev/null
+++ b/collects/typed-scheme/private/lexical-env.ss
@@ -0,0 +1,51 @@
+(module lexical-env mzscheme
+  
+  (require "type-environments.ss" "tc-utils.ss" "type-env.ss" "mutated-vars.ss")
+  
+  (provide (all-defined))
+  
+  ;; the current lexical environment
+  (define lexical-env (make-parameter (make-empty-env module-identifier=?)))
+  
+  ;; run code in a new env
+  (define-syntax with-lexical-env
+    (syntax-rules ()
+      [(_ e . b) (parameterize ([lexical-env e]) . b)]))
+  
+  ;; run code in an extended env
+  (define-syntax with-lexical-env/extend
+    (syntax-rules ()
+      [(_ is ts . b) (parameterize ([lexical-env (extend/values is ts (lexical-env))]) . b)]))
+
+  ;; find the type of identifier i, looking first in the lexical env, then in the top-level env
+  ;; identifer -> Type
+  (define (lookup-type/lexical i)
+    (lookup (lexical-env) i 
+            (lambda (i) (lookup-type i))))
+  
+  ;; refine the type of i in the lexical env
+  ;; (identifier type -> type) identifier -> environment
+  (define (update-type/lexical f i)
+    ;; do the updating on the given env
+    ;; (identifier type -> type) identifier environment -> environment
+    (define (update f k env)
+      (parameterize
+          ([current-orig-stx k])
+        (let* ([v (lookup-type/lexical k)]
+               [new-v (f k v)]
+               [new-env (extend env k new-v)])
+          new-env)))
+    ;; check if i is ever the target of a set!
+    (if (is-var-mutated? i)
+        ;; if it is, we do nothing
+        (lexical-env)
+        ;; otherwise, refine the type
+        (update f i (lexical-env))))
+  
+  ;; convenience macro for typechecking in the context of an updated env
+  (define-syntax with-update-type/lexical
+    (syntax-rules ()
+      [(_ f i . b)
+       (with-lexical-env (update-type/lexical f i) . b)]))
+
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/mutated-vars.ss b/collects/typed-scheme/private/mutated-vars.ss
new file mode 100644
index 0000000000..b55ce41c3e
--- /dev/null
+++ b/collects/typed-scheme/private/mutated-vars.ss
@@ -0,0 +1,52 @@
+(module mutated-vars mzscheme
+    
+  (require-for-template mzscheme)
+  (require (lib "boundmap.ss" "syntax")
+           (lib "kerncase.ss" "syntax")
+           (lib "trace.ss"))
+  
+  ;; mapping telling whether an identifer is mutated
+  ;; maps id -> boolean
+  (define table (make-module-identifier-mapping))
+  
+  ;; find and add to mapping all the set!'ed variables in form
+  ;; syntax -> void
+  (define (find-mutated-vars form)
+    ;; syntax -> void
+    (define (fmv/list lstx)
+      (for-each find-mutated-vars (syntax->list lstx)))
+    ;(printf "called with ~a~n" (syntax-object->datum form))
+    (kernel-syntax-case* form #f (define-type-alias-internal define-typed-struct-internal require/typed-internal #%app lambda)     
+      ;; what we care about: set!
+      [(set! v e)
+       (begin
+         ;(printf "mutated var found: ~a~n" (syntax-e #'v))
+         (module-identifier-mapping-put! table #'v #t))]
+      [(define-values (var ...) expr)
+       (find-mutated-vars #'expr)]
+      [(#%app . rest) (fmv/list #'rest)]
+      [(begin . rest) (fmv/list #'rest)]
+      [(begin0 . rest) (fmv/list #'rest)]
+      [(lambda _ . rest) (fmv/list #'rest)]
+      [(case-lambda (_ . rest) ...) (for-each fmv/list (syntax->list #'(rest ...)))]
+      [(if e1 e2) (begin (find-mutated-vars #'e1) (find-mutated-vars #'e2))]
+      [(if e1 e2 e3) (begin (find-mutated-vars #'e1) (find-mutated-vars #'e1) (find-mutated-vars #'e3))]
+      [(with-continuation-mark e1 e2 e3) (begin (find-mutated-vars #'e1) 
+                                                (find-mutated-vars #'e1)
+                                                (find-mutated-vars #'e3))]
+      [(let-values ([_ e] ...) . b) (begin (fmv/list #'(e ...))
+                                           (fmv/list #'b))]
+      [(letrec-values ([_ e] ...) . b) (begin (fmv/list #'(e ...))
+                                              (fmv/list #'b))]  
+      ;; 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)))
+  
+  (provide find-mutated-vars is-var-mutated?)
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/nest.ss b/collects/typed-scheme/private/nest.ss
new file mode 100644
index 0000000000..1cccc99ed0
--- /dev/null
+++ b/collects/typed-scheme/private/nest.ss
@@ -0,0 +1,10 @@
+#lang scheme/base
+
+(provide nest)
+
+(define-syntax nest
+  (syntax-rules ()
+    [(nest () body0 body ...)
+     (let () body0 body ...)]
+    [(nest ([form forms ...] . more) body0 body ...)
+     (form forms ... (nest more body0 body ...))]))
diff --git a/collects/typed-scheme/private/parse-type.ss b/collects/typed-scheme/private/parse-type.ss
new file mode 100644
index 0000000000..f4e16dd98e
--- /dev/null
+++ b/collects/typed-scheme/private/parse-type.ss
@@ -0,0 +1,210 @@
+#lang scheme/base
+
+(provide parse-type parse-type/id)
+
+(require (except-in "type-rep.ss" make-arr)
+         "type-effect-convenience.ss"
+         (only-in "type-effect-convenience.ss" [make-arr* make-arr])
+         "tc-utils.ss"
+         "union.ss"
+         (lib "stx.ss" "syntax")
+         (except-in "type-environments.ss")
+         "type-name-env.ss"
+         "type-alias-env.ss"
+         "type-utils.ss"
+         (only-in (lib "list.ss") foldl foldr)
+         #;(except-in (lib "list.ss"  "srfi" "1") unfold remove)
+         (lib "plt-match.ss"))
+
+(define enable-mu-parsing (make-parameter #t))
+
+
+(define (parse-type/id loc datum)
+  #;(printf "parse-type/id id : ~a~n ty: ~a~n" (syntax-object->datum loc) (syntax-object->datum stx))
+  (let* ([stx* (datum->syntax loc datum loc loc)])
+    (parse-type stx*)))
+
+(define (stx-cadr stx) (stx-car (stx-cdr stx)))
+
+
+(define (parse-type stx)    
+  (parameterize ([current-orig-stx stx])
+    (syntax-case* stx ()
+      symbolic-identifier=?             
+      [(fst . rst)
+       (not (syntax->list #'rst))
+       (-pair (parse-type #'fst) (parse-type #'rst))]
+      [(Class (pos-args ...) ([fname fty . rest] ...) ([mname mty] ...))
+       (eq? (syntax-e #'Class) 'Class)
+       (make-Class
+        (map parse-type (syntax->list #'(pos-args ...)))
+        (map list
+             (map syntax-e (syntax->list #'(fname ...)))
+             (map parse-type (syntax->list #'(fty ...)))
+             (map (lambda (e) (syntax-case e ()
+                                [(#t) #t]
+                                [_ #f]))
+                  (syntax->list #'(rest ...))))
+        (map list
+             (map syntax-e (syntax->list #'(mname ...)))
+             (map parse-type (syntax->list #'(mty ...)))))]
+      [(Instance t)
+       (eq? (syntax-e #'Instance) 'Instance)
+       (let ([v (parse-type #'t)])
+         (unless (or (Mu? v) (Class? v) (Union? v))
+           (tc-error "Argument to Instance must be a class type, got ~a" v))
+         (make-Instance v))]
+      [(Tuple ts ...)
+       (or (eq? (syntax-e #'Tuple) 'Tuple)
+           (eq? (syntax-e #'Tuple) 'List))
+       (begin
+         (add-type-name-reference (stx-car stx))
+         (-Tuple (map parse-type (syntax->list #'(ts ...)))))]
+      [(cons fst rst)
+       (eq? (syntax-e #'cons) 'cons)
+       (-pair (parse-type #'fst) (parse-type #'rst))]
+      [(pred t) 
+       (eq? (syntax-e #'pred) 'pred)
+       (make-pred-ty (parse-type #'t))]
+      [(dom -> rng : pred-ty)
+       (and 
+        (eq? (syntax-e #'->) '->)
+        (eq? (syntax-e #':) ':))
+       (begin
+         (add-type-name-reference (stx-cadr stx))
+         (make-pred-ty (list (parse-type #'dom)) (parse-type #'rng) (parse-type #'pred-ty)))]
+      [(dom ... rest ::: -> rng)
+       (and (eq? (syntax-e #'->) '->) 
+            (or (symbolic-identifier=? #'::: (quote-syntax ..))
+                (symbolic-identifier=? #'::: (quote-syntax ...))))
+       (begin
+         (add-type-name-reference #'->)
+         (->* (map parse-type (syntax->list #'(dom ...))) (parse-type #'rest) (parse-type #'rng)))]
+      ;; has to be below the previous one
+      [(dom ... -> rng) 
+       (eq? (syntax-e #'->) '->)
+       (begin
+         (add-type-name-reference #'->)
+         (->* (map parse-type (syntax->list #'(dom ...))) (parse-type #'rng)))]
+      [(values tys ...) 
+       (eq? (syntax-e #'values) 'values)
+       (-values (map parse-type (syntax->list #'(tys ...))))]
+      [(case-lambda tys ...) 
+       (eq? (syntax-e #'case-lambda) 'case-lambda)
+       (make-Function (map (lambda (ty) 
+                             (syntax-case* ty (->) symbolic-identifier=?
+                               [(dom ... -> rng)
+                                (make-arr 
+                                 (map parse-type (syntax->list #'(dom ...))) 
+                                 (parse-type #'rng))]))
+                           (syntax->list #'(tys ...))))]
+      ;; I wish I could write this
+      #;[(case-lambda ([dom ... -> rng] ...)) (make-funty (list (make-arr (list (parse-type #'dom) ...) (parse-type #'rng)) ...))]
+      #;[(list-of t) (make-lst (parse-type #'t))]
+      #;[(Listof t) (make-lst (parse-type #'t))]
+      [(Vectorof t) 
+       (eq? (syntax-e #'Vectorof) 'Vectorof)
+       (begin
+         (add-type-name-reference #'Vectorof)
+         (make-Vector (parse-type #'t)))]
+      [(mu x t) 
+       (and (identifier? #'x)
+            (memq (syntax-e #'mu) '(mu Rec))
+            (enable-mu-parsing))
+       (let* ([var (syntax-e #'x)]
+              [tvar (make-F var)])
+         (add-type-name-reference #'mu)           
+         (parameterize ([current-tvars (extend-env (list var) (list tvar) (current-tvars))])
+           (make-Mu var (parse-type #'t))))]
+      [(U ts ...)
+       (eq? (syntax-e #'U) 'U)
+       (begin
+         (add-type-name-reference #'U)
+         (apply Un (map parse-type (syntax->list #'(ts ...)))))]
+      [(Un-pat ts ...) 
+       (eq? (syntax-e #'Un-pat) 'Un)
+       (apply Un (map parse-type (syntax->list #'(ts ...))))]
+      [(quot t)
+       (eq? (syntax-e #'quot) 'quote)
+       (-val (syntax-e #'t))]
+      [(All (vars ...) t) 
+       (and (eq? (syntax-e #'All) 'All)
+            (andmap identifier? (syntax->list #'(vars ...))))
+       (let* ([vars (map syntax-e (syntax->list #'(vars ...)))]
+              [tvars (map make-F vars)])
+         (add-type-name-reference #'All)
+         (parameterize ([current-tvars (extend-env vars tvars (current-tvars))])
+           (make-Poly vars (parse-type #'t))))]        
+      [(Opaque p?) 
+       (eq? (syntax-e #'Opaque) 'Opaque)
+       (begin
+         (add-type-name-reference #'Opaque)
+         (make-Opaque #'p? (syntax-local-certifier)))]
+      [(Parameter t) 
+       (eq? (syntax-e #'Parameter) 'Parameter)
+       (let ([ty (parse-type #'t)])
+         (add-type-name-reference #'Parameter)
+         (-Param ty ty))]
+      [(Parameter t1 t2)
+       (eq? (syntax-e #'Parameter) 'Parameter)
+       (begin
+         (add-type-name-reference #'Parameter)
+         (-Param (parse-type #'t1) (parse-type #'t2)))]
+      
+      [id
+       (identifier? #'id)
+       (cond 
+         ;; if it's a type variable, we just produce the corresponding reference (which is in the HT)
+         [(lookup (current-tvars) (syntax-e #'id) (lambda (_) #f))]
+         ;; if it's a type alias, we expand it (the expanded type is stored in the HT)
+         [(lookup-type-alias #'id parse-type (lambda () #f))
+          =>
+          (lambda (t)
+            (add-type-name-reference #'id)
+            t)]
+         ;; if it's a type name, we just use the name
+         [(lookup-type-name #'id (lambda () #f))
+          (add-type-name-reference #'id)
+          (make-Name #'id)]
+         [else
+          (tc-error "unbound type ~a" (syntax-e #'id))])]     
+
+      [(All . rest) (eq? (syntax-e #'All) 'All) (tc-error "All: bad syntax")]
+      [(Opaque . rest) (eq? (syntax-e #'Opaque) 'Opqaue) (tc-error "Opaque: bad syntax")]
+      [(U . rest) (eq? (syntax-e #'U) 'U) (tc-error "Union: bad syntax")]
+      [(Vectorof . rest) (eq? (syntax-e #'Vectorof) 'Vectorof) (tc-error "Vectorof: bad syntax")]
+      [(mu . rest) (eq? (syntax-e #'mu) 'mu) (tc-error "mu: bad syntax")]
+      [(Un . rest) (eq? (syntax-e #'Un) 'Un) (tc-error "Union: bad syntax")]
+      [(t ... -> . rest) (eq? (syntax-e #'->) '->) (tc-error "->: bad syntax")]
+      
+
+      [(id arg args ...)
+       (let loop 
+         ([rator (parse-type #'id)]
+          [args (map parse-type (syntax->list #'(arg args ...)))])
+         (match rator
+           [(Name: _)
+            (make-App rator args stx)]
+           [(Poly: ns _)
+            (unless (= (length args) (length ns))
+              (tc-error "Wrong number of arguments to type ~a, expected ~a but got ~a" rator (length ns) (length args)))
+            (instantiate-poly rator args)]
+           [(Mu: _ _) (loop (unfold rator) args)]
+           [_ (tc-error "Type ~a cannot be applied, arguments were: ~a" rator args)]))
+       #;
+       (let ([ty (parse-type #'id)])
+         #;(printf "ty is ~a" ty)
+         (unless (Poly? ty)
+           (tc-error "not a polymorphic type: ~a" (syntax-e #'id)))
+         (unless (= (length (syntax->list #'(arg args ...))) (Poly-n ty))
+           (tc-error "wrong number of arguments to type constructor ~a: expected ~a, got ~a" 
+                     (syntax-e #'id)
+                     (Poly-n ty)
+                     (length (syntax->list #'(arg args ...)))))
+         (instantiate-poly ty (map parse-type (syntax->list #'(arg args ...)))))]
+      [t
+       (or (boolean? (syntax-e #'t)) (number? (syntax-e #'t))
+           (string? (syntax-e #'t)))
+       (-val (syntax-e #'t))]
+      [_ (tc-error "not a valid type: ~a" (syntax->datum stx))])))
+
diff --git a/collects/typed-scheme/private/planet-requires.ss b/collects/typed-scheme/private/planet-requires.ss
new file mode 100644
index 0000000000..0c21dc6017
--- /dev/null
+++ b/collects/typed-scheme/private/planet-requires.ss
@@ -0,0 +1,49 @@
+#lang scheme/base
+
+(require (for-syntax scheme/base scheme/require-transform))
+
+(define-for-syntax (splice-requires specs)  
+  (define subs (map (compose cons expand-import) specs))
+  (values (apply append (map car subs)) (apply append (map cdr subs))))
+
+(define-syntax define-module
+  (lambda (stx)
+    (syntax-case stx ()
+      [(_ nm spec ...)
+       (syntax/loc stx
+         (define-syntax nm
+           (make-require-transformer
+            (lambda (stx)
+              (splice-requires (list (syntax-local-introduce (quote-syntax spec)) ...))))))])))
+
+(define-syntax planet/multiple
+  (make-require-transformer
+   (lambda (stx)
+     (syntax-case stx ()
+       [(_ plt files ...)
+        (let ([mk (lambda (spc)
+                    (syntax-case spc (prefix-in)
+                      [e
+                       (string? (syntax-e #'e))
+                       (datum->syntax spc `(planet ,#'e ,#'plt) spc)]
+                      [(prefix-in p e)
+                       (datum->syntax spc `(prefix-in ,#'p (planet ,#'e ,#'plt)) spc)]))])
+          (splice-requires (map mk (syntax->list #'(files ...)))))]))))
+
+
+(provide galore schemeunit)
+;; why is this neccessary?
+(provide planet/multiple)
+
+(define-module galore
+  (prefix-in table: "tables.ss"))
+
+(define-module schemeunit 
+  (planet/multiple ("schematics" "schemeunit.plt" 2 3)
+                   "test.ss"
+                   "graphical-ui.ss"
+                   "text-ui.ss"
+                   "util.ss")
+  (planet/multiple ("cce" "fasttest.plt" 1 2)
+                   "random.ss"
+                   "schemeunit.ss"))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/prims.ss b/collects/typed-scheme/private/prims.ss
new file mode 100644
index 0000000000..29bb988ab1
--- /dev/null
+++ b/collects/typed-scheme/private/prims.ss
@@ -0,0 +1,335 @@
+#lang scheme/base
+
+#|
+
+This file defines two sorts of primitives. All of them are provided into any module using the typed scheme language.
+
+1. macros for defining type annotated code. 
+   this includes: lambda:, define:, etc
+   potentially, these macros should be replacements for the mzscheme ones in the user program
+   however, it's nice to be able to use both when the sugar is more limited
+   for example: (define ((f x) y) (+ x y))
+
+2. macros for defining 'magic' code
+   examples: define-typed-struct, require/typed
+   these expand into (ignored) mzscheme code, and declarations that a typechecker understands
+   in order to protect the declarations, they are wrapped in `#%app void' so that local-expand of the module body
+   will not expand them on the first pass of the macro expander (when the stop list is ignored)
+
+|#
+
+
+(provide (all-defined-out))
+
+(require (for-syntax 
+          scheme/base
+          "type-rep.ss"
+          (lib "match.ss")
+          "parse-type.ss"
+          (lib "struct.ss" "syntax")
+          (lib "stx.ss" "syntax")
+          "utils.ss"   
+          "tc-utils.ss"
+          "type-name-env.ss"
+          "type-contract.ss"))
+
+(require "require-contract.ss"
+         "internal-forms.ss"
+         "planet-requires.ss"           
+         (lib "etc.ss")
+         (except-in (lib "contract.ss") ->)
+         (only-in (lib "contract.ss") [-> c->])
+         (lib "struct.ss")
+         "base-env.ss")
+
+
+
+
+
+
+
+(define-for-syntax (ignore stx) (syntax-property stx 'typechecker:ignore #t))
+
+(define-for-syntax (internal stx)
+  (quasisyntax/loc stx
+    (define-values ()
+      (begin
+        (quote-syntax #,stx)
+        (#%plain-app values)))))
+
+
+
+(define-syntax (require/typed stx)
+  
+  (syntax-case* stx (rename) (lambda (x y) (eq? (syntax-e x) (syntax-e y)))
+    [(_ lib [nm ty] ...)
+     #'(begin (require/typed nm ty lib) ...)]
+    [(_ nm ty lib)
+     (identifier? #'nm)
+     (quasisyntax/loc stx (begin 
+                            #,(syntax-property (syntax-property #'(define cnt* #f)
+                                                                'typechecker:contract-def #'ty)
+                                               'typechecker:ignore #t)
+                            #,(internal #'(require/typed-internal nm ty))
+                            #,(syntax-property #'(require/contract nm cnt* lib)
+                                               'typechecker:ignore #t)))]
+    [(_ (rename internal-nm nm) ty lib)
+     (raise-syntax-error "rename not currently supported" stx)
+     #; #;
+     (identifier? #'nm)
+     (quasisyntax/loc stx (begin 
+                            #,(syntax-property (syntax-property #'(define cnt* #f)
+                                                                'typechecker:contract-def #'ty)
+                                               'typechecker:ignore #t)
+                            #,(internal #'(require/typed-internal internal-nm ty))
+                            #,(syntax-property #'(require/contract nm cnt* lib)
+                                               'typechecker:ignore #t)))]))      
+
+(define-syntax (require/opaque-type stx)
+  (syntax-case stx ()
+    [(_ ty pred lib)
+     (and (identifier? #'ty) (identifier? #'pred))
+     (begin
+       (register-type-name #'ty (make-Opaque #'pred (syntax-local-certifier)))
+       (quasisyntax/loc stx
+         (begin 
+           #,(syntax-property #'(define pred-cnt (any/c . c-> . boolean?))
+                              'typechecker:ignore #t)
+           #,(internal #'(require/typed-internal pred (Any -> Boolean : (Opaque pred))))
+           (define-type-alias ty (Opaque pred))
+           #,(syntax-property #'(require/contract pred pred-cnt lib)
+                              'typechecker:ignore #t))))]))
+
+(define-for-syntax (types-of-formals stx src)
+  (syntax-case stx (:)
+    [([var : ty] ...) (quasisyntax/loc stx (ty ...))]
+    [([var : ty] ... . [rest : rest-ty]) (syntax/loc stx (ty ... rest-ty ..))]
+    [_
+     (let loop ([stx stx])
+       (syntax-case stx ()
+         ;; should never happen
+         [() (raise-syntax-error #f "bad annotation syntax" src stx)]
+         [([var : ty] . rest)
+          (identifier? #'var)
+          (loop #'rest)]
+         [([var : ty] . rest)
+          (raise-syntax-error #f "not a variable" src #'var)]
+         [(e . rest)
+          (raise-syntax-error #f "expected annotated variable of the form [x : T], got something else" src #'e)]))]))
+
+
+(define-syntax (plambda: stx)
+  (syntax-case stx ()
+    [(plambda: (tvars ...) formals . body)
+     (syntax-property #'(lambda: formals . body)
+                      'typechecker:plambda
+                      #'(tvars ...))]))
+
+(define-syntax (pcase-lambda: stx)
+  (syntax-case stx ()
+    [(pcase-lambda: (tvars ...) cl ...)
+     (syntax-property #'(case-lambda: cl ...)
+                      'typechecker:plambda
+                      #'(tvars ...))]))
+
+(define-syntax (pdefine: stx)
+  (syntax-case stx (:)
+    [(pdefine: tvars (nm . formals) : ret-ty . body)
+     (with-syntax* ([(tys ...) (types-of-formals #'formals stx)]
+                    [type (syntax/loc #'ret-ty (All tvars (tys ... -> ret-ty)))])
+                   (syntax/loc stx
+                     (define: nm : type
+                       (plambda: tvars formals . body))))]))
+
+(define-syntax (ann stx)
+  (syntax-case stx (:)
+    [(_ arg : ty)
+     #;#'(let: ([id : ty arg]) id)
+     (syntax-property #'arg 'type-ascription #'ty)]))
+
+(define-syntax (: stx)
+  (let ([stx*
+         ;; make it possible to add another colon after the id for clarity
+         (syntax-case stx (:)
+           [(: id : . more) (syntax/loc stx (: id . more))]
+           [_ stx])])
+    (syntax-case stx* ()
+      [(_ id ty)
+       (identifier? #'id)
+       (syntax-property
+        (internal (syntax/loc stx (:-internal id ty)))
+        'disappeared-use #'id)]
+      [(_ id ty)
+       (raise-syntax-error '|type declaration| "can only annotate identifiers with types"
+                           stx #'id)]
+      [(_ _ _ _ . _)
+       (raise-syntax-error '|type declaration| "too many arguments" stx)]
+      [(_ _)
+       (raise-syntax-error '|type declaration| "too few arguments" stx)])))
+
+(define-syntax (inst stx)
+  (syntax-case stx (:)
+    [(_ arg : tys ...)
+     (syntax-property #'arg 'type-inst #'(tys ...))]))
+
+(define-syntax (define: stx)
+  (syntax-case stx (:)
+    [(define: (nm . formals) : ret-ty body ...)
+     (identifier? #'nm)
+     (with-syntax* ([(tys ...) (types-of-formals #'formals stx)]
+                    [arrty (syntax/loc stx (tys ... -> ret-ty))])
+                   (syntax/loc stx
+                     (define: nm : arrty
+                       (lambda: formals body ...))))]
+    [(define: nm : ty body)
+     (identifier? #'nm)
+     (with-syntax ([new-nm (syntax-property #'nm 'type-label #'ty)])
+       (syntax/loc stx (define new-nm body)))]
+    [(define: (vars ...) (f args ...) : ret body ...)
+     (andmap identifier? (syntax->list #'(vars ...)))
+     #'(pdefine: (vars ...) (f args ...) : ret body ...)]
+    [(define: (nm . formals) body ...)
+     (raise-syntax-error #f "missing return type annotation" stx)]
+    [(define: nm body)
+     (raise-syntax-error #f "missing type annotation" stx)]))
+
+
+;; helper function for annoating the bound names
+(define-for-syntax (annotate-names stx)
+  (define (label-one var ty)
+    (syntax-property var 'type-label ty))
+  (define (label vars tys)
+    (map label-one
+         (syntax->list vars)
+         (syntax->list tys)))
+  (syntax-case stx (:)
+    [[var : ty] (label-one #'var #'ty)]
+    [([var : ty] ...)
+     (label #'(var ...) #'(ty ...))]
+    [([var : ty] ... . [rest : rest-ty])
+     (append (label #'(var ...) #'(ty ...)) (label-one #'rest #'rest-ty))]))       
+
+(define-syntax-rule (λ: . args) (lambda: . args))
+
+(define-syntax (lambda: stx)
+  (syntax-case stx (:)
+    [(lambda: formals . body)
+     (with-syntax ([labeled-formals (annotate-names #'formals)])
+       (syntax/loc stx (lambda labeled-formals . body)))]))
+
+(define-syntax (case-lambda: stx)
+  (syntax-case stx (:)
+    [(case-lambda: [formals . body] ...)
+     (with-syntax ([(lab-formals ...) (map annotate-names (syntax->list #'(formals ...)))])
+       (syntax/loc stx (case-lambda [lab-formals . body] ...)))]))
+
+(define-syntaxes (let-internal: let*: letrec:)
+  (let ([mk (lambda (form)
+              (lambda (stx)
+                (syntax-case stx (:)
+                  [(_ ([nm : ty . exprs] ...) . body)
+                   (with-syntax* ([(vars ...) (annotate-names #'([nm : ty] ...))]
+                                  [bindings (map (lambda (v e loc)
+                                                   (quasisyntax/loc loc [#,v . #,e]))
+                                                 (syntax->list #'(vars ...))
+                                                 (syntax->list #'(exprs ...))
+                                                 (syntax->list (syntax-case stx () [(_ bs . body) #'bs])))])
+                                 (quasisyntax/loc stx (#,form bindings . body)))])))])
+    (values (mk #'let) (mk #'let*) (mk #'letrec))))
+
+(define-syntax (let: stx)
+  (syntax-case stx (:)
+    [(let: nm : ret-ty ([arg : ty val] ...) . body)
+     (identifier? #'nm)
+     (syntax/loc stx ((letrec: ([nm : (ty ... -> ret-ty) (lambda: ([arg : ty] ...) . body)]) nm) val ...))]
+    [(let: . rest)
+     (syntax/loc stx (let-internal: . rest))]))
+
+(define-syntax (define-type-alias stx)
+  (syntax-case stx ()
+    [(_ tname rest) 
+     (identifier? #'tname)
+     (begin
+       #`(begin
+           #,(ignore #'(define-syntax tname (lambda (stx) (raise-syntax-error 'type-check "type name used out of context" stx))))
+           #,(internal (syntax/loc stx (define-type-alias-internal tname rest)))))]
+    [(_ (tname . args) rest)
+     (andmap identifier? (syntax->list #'args))
+     #'(define-type-alias tname (All args rest))]))
+
+(define-syntax (define-typed-struct/exec stx)
+  (syntax-case stx (:)
+    [(_ nm ([fld : ty] ...) [proc : proc-ty])
+     (with-syntax* 
+      ([proc* (syntax-property #'(ann proc : proc-ty) 'typechecker:with-type #t)]
+       [d-s (syntax-property (syntax/loc stx (define-struct/properties nm (fld ...)
+                                               ([prop:procedure proc*])))
+                             'typechecker:ignore-some #t)]
+       [dtsi (internal (syntax/loc stx (define-typed-struct/exec-internal nm ([fld : ty] ...) proc-ty)))])
+      #'(begin d-s dtsi))]))
+
+(define-syntax (with-handlers: stx)
+  (syntax-case stx ()
+    [(_ ([pred? action] ...) . body)
+     (with-syntax ([(pred?* ...) (map (lambda (s) (syntax-property #`(ann #,s : (Any -> Any)) 'typechecker:with-type #t))
+                                      (syntax->list #'(pred? ...)))]
+                   [(action* ...)
+                    (map (lambda (s) (syntax-property s 'typechecker:exn-handler #t)) (syntax->list #'(action ...)))]
+                   [body* (syntax-property #'(begin . body) 'typechecker:exn-body #t)])
+       (syntax-property #'(with-handlers ([pred?* action*] ...) body*)
+                        'typechecker:with-handlers
+                        #t))]))
+
+(define-syntax (define-typed-struct stx)
+  (syntax-case stx (:)
+    [(_ nm ([fld : ty] ...) . opts)
+     (with-syntax ([d-s (syntax-property (syntax/loc stx (define-struct nm (fld ...) . opts))
+                                         'typechecker:ignore #t)]
+                   [dtsi (internal (syntax/loc stx (define-typed-struct-internal nm ([fld : ty] ...))))])
+       #'(begin d-s dtsi))]
+    [(_ (vars ...) nm ([fld : ty] ...) . opts)
+     (with-syntax ([d-s (syntax-property (syntax/loc stx (define-struct nm (fld ...) . opts))
+                                         'typechecker:ignore #t)]
+                   [dtsi (internal (syntax/loc stx (define-typed-struct-internal (vars ...) nm ([fld : ty] ...))))])
+       #'(begin d-s dtsi))]))
+
+(define-syntax (require-typed-struct stx)
+  (syntax-case stx (:)
+    [(_ nm ([fld : ty] ...) lib)
+     (with-syntax* ([(struct-info maker pred sel ...) (build-struct-names #'nm (syntax->list #'(fld ...)) #f #t)]
+                    [oty #'(Opaque pred)])
+                   #'(begin
+                       (require/opaque-type nm pred lib)
+                       (require/typed maker (ty ... -> oty) lib)
+                       (require/typed sel (oty -> ty) lib) ...))]))
+
+(define-syntax (do: stx)
+  (syntax-case stx (:)
+    [(_ : ty ((var : tys init . step) ...) (e0 e1 ...) c ...)
+     (with-syntax ([(step ...)
+                    (map (lambda (v s)
+                           (syntax-case s ()
+                             [() v]
+                             [(e) #'e]
+                             [_ (raise-syntax-error 
+                                 #f
+                                 "bad variable syntax"
+                                 stx)]))
+                         (syntax->list #'(var ...))
+                         (syntax->list #'(step ...)))])
+       (syntax-case #'(e1 ...) ()
+         [() (syntax/loc
+                 stx
+               (let: doloop : ty ([var : tys init] ...)
+                     (if (not e0)
+                         (begin c ... (doloop step ...)))))]
+         [(e1 e2 ...)
+          (syntax/loc
+              stx
+            (let: doloop : ty ([var : tys init] ...)
+                  (if e0
+                      (begin e1 e2 ...)
+                      (begin c ... (doloop step ...)))))]))]))
+
+
+
diff --git a/collects/typed-scheme/private/provide-handling.ss b/collects/typed-scheme/private/provide-handling.ss
new file mode 100644
index 0000000000..e9fcc99e75
--- /dev/null
+++ b/collects/typed-scheme/private/provide-handling.ss
@@ -0,0 +1,109 @@
+#lang scheme/base
+
+(require (only-in (lib "1.ss" "srfi") [assoc assoc*])
+         (prefix-in 1: (lib "1.ss" "srfi"))
+         (lib "kerncase.ss" "syntax")
+         (lib "struct.ss" "syntax")
+         (lib "stx.ss" "syntax")
+         (lib "etc.ss")
+         (except-in (lib "list.ss") remove)
+         "type-contract.ss"
+         "signatures.ss"
+         "tc-structs.ss"
+         "utils.ss" ;; doesn't need tests
+         "type-rep.ss" ;; doesn't need tests
+         "unify.ss" ;; needs tests
+         "infer.ss"
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "union.ss"
+         "subtype.ss" ;; has tests
+         "internal-forms.ss" ;; doesn't need tests
+         "planet-requires.ss" ;; doesn't need tests
+         "type-env.ss" ;; maybe needs tests
+         "parse-type.ss" ;; has tests
+         "tc-utils.ss" ;; doesn't need tests
+         "type-environments.ss" ;; doesn't need tests
+         "lexical-env.ss" ;; maybe needs tests
+         "type-annotation.ss" ;; has tests
+         "type-name-env.ss" ;; maybe needs tests
+         "init-envs.ss"
+         "effect-rep.ss"
+         "mutated-vars.ss"
+         "def-binding.ss"
+         (lib "plt-match.ss"))
+
+(provide remove-provides provide? generate-prov)
+
+(define (provide? form)
+  (kernel-syntax-case form #f
+    [(#%provide . rest) form]
+    [_ #f]))
+
+(define (remove-provides forms)
+  (filter (lambda (e) (not (provide? e))) (syntax->list forms)))
+
+(define ((generate-prov stx-defs val-defs) form)
+  (define (mem? i vd)
+    (cond [(1:member i vd (lambda (i j) (free-identifier=? i (binding-name j)))) => car]
+          [else #f]))
+  (define (lookup-id i vd)
+    (def-binding-ty (mem? i vd)))
+  (define (mk internal-id external-id)
+    (cond
+      [(mem? internal-id val-defs) 
+       =>
+       (lambda (b)
+         (with-syntax ([id internal-id]
+                       [out-id external-id])
+           (cond [(type->contract (def-binding-ty b) (lambda () #f)) 
+                  =>
+                  (lambda (cnt)                                    
+                    (with-syntax ([(export-id cnt-id) (generate-temporaries #'(id id))])
+                      #`(begin 
+                          (define/contract cnt-id #,cnt id)
+                          (define-syntax export-id
+                            (if (unbox typed-context?)
+                                (make-rename-transformer #'id)
+                                (make-rename-transformer #'cnt-id)))
+                          (#%provide (rename export-id out-id)))))]
+                 [else 
+                  (with-syntax ([(export-id) (generate-temporaries #'(id))])
+                    #`(begin                             
+                        (define-syntax export-id
+                          (if (unbox typed-context?)
+                              (make-rename-transformer #'id)
+                              (lambda (stx) (tc-error/stx stx "The type of ~a cannot be converted to a contract" (syntax-e #'id)))))
+                        (provide (rename export-id out-id))))])))]
+      [(mem? internal-id stx-defs) 
+       =>
+       (lambda (b)
+         (with-syntax ([id internal-id]
+                       [out-id external-id])
+           (with-syntax ([(export-id cnt-id) (generate-temporaries #'(id id))])
+             #`(begin                    
+                 (define-syntax export-id
+                   (if (unbox typed-context?)
+                       (make-rename-transformer #'id)
+                       (lambda (stx)
+                         (tc-error/stx stx "Macro ~a from typed module used in untyped code" (syntax-e #'out-id)))))
+                 (provide (rename export-id out-id))))))]
+      [(eq? (syntax-e internal-id) (syntax-e external-id))
+       #`(provide #,internal-id)]
+      [else #`(provide (rename #,internal-id #,external-id))]))
+  (kernel-syntax-case form #f
+    [(#%provide form ...)
+     (map 
+      (lambda (f)
+        (parameterize ([current-orig-stx f])
+          (syntax-case* f (struct rename all-defined protect all-defined-except all-from all-from-except) 
+            (lambda (a b) (eq? (syntax-e a) (syntax-e b)))
+            [id 
+             (identifier? #'id)
+             (mk #'id #'id)]
+            [(rename in out)
+             (mk #'in #'out)]
+            [(protect . _)
+             (tc-error "provide: protect not supported by Typed Scheme")]
+            [_ (int-err "unknown provide form")])))
+      (syntax->list #'(form ...)))]
+    [_ (int-err "non-provide form! ~a" (syntax->datum form))]))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/remove-intersect.ss b/collects/typed-scheme/private/remove-intersect.ss
new file mode 100644
index 0000000000..6765e21574
--- /dev/null
+++ b/collects/typed-scheme/private/remove-intersect.ss
@@ -0,0 +1,96 @@
+#lang scheme/base
+
+(require "type-rep.ss" "unify.ss" "union.ss" "infer.ss" "subtype.ss"
+         "type-utils.ss" "resolve-type.ss" "type-effect-convenience.ss"
+         mzlib/plt-match mzlib/trace)
+
+(provide restrict (rename-out [*remove remove]) overlap)
+
+
+(define (overlap t1 t2)
+  (match (list t1 t2)        
+    [(list (Univ:) _) #t]
+    [(list _ (Univ:)) #t]
+    [(list (F: _) _) #t]
+    [(list _ (F: _)) #t]
+    [(list (Name: n) (Name: n*)) (free-identifier=? n n*)]
+    [(list (? Mu?) _) (overlap (unfold t1) t2)]
+    [(list _ (? Mu?)) (overlap t1 (unfold t2))]
+    [(list (Union: e) t)
+     (ormap (lambda (t*) (overlap t* t)) e)]
+    [(list t (Union: e))
+     (ormap (lambda (t*) (overlap t t*)) e)]
+    [(or (list _ (? Poly?)) (list (? Poly?) _))
+     #t] ;; these can have overlap, conservatively
+    [(list (Base: s1) (Base: s2)) (eq? s1 s2)]
+    [(list (Base: _) (Value: _)) (subtype t2 t1)] ;; conservative
+    [(list (Value: _) (Base: _)) (subtype t1 t2)] ;; conservative
+    [(list (Syntax: t) (Syntax: t*))
+     (overlap t t*)]
+    [(or (list (Syntax: _) _)
+         (list _ (Syntax: _)))
+     #f]    
+    [(list (Base: _) _) #f]
+    [(list _ (Base: _)) #f]
+    [(list (Value: (? pair? v)) (Pair: _ _)) #t]
+    [(list (Pair: _ _) (Value: (? pair? v))) #t]
+    [(list (Pair: a b) (Pair: a* b*))
+     (and (overlap a a*)
+          (overlap b b*))]
+    [(or (list (Pair: _ _) _)
+         (list _ (Pair: _ _)))
+     #f]
+    [else #t]))
+
+;; this is *definitely* not yet correct
+
+;; NEW IMPL
+;; restrict t1 to be a subtype of t2
+(define (restrict t1 t2)     
+  ;; we don't use union map directly, since that might produce too many elements
+  (define (union-map f l)
+    (match l
+      [(Union: es) 
+       (let ([l (map f es)])
+         ;(printf "l is ~a~n" l)
+         (apply Un l))]))
+  (cond
+    [(subtype t1 t2) t1] ;; already a subtype          
+    [(match t2
+       [(Poly: vars t)
+        (let ([subst (infer t t1 vars)])
+          (and subst (restrict t1 (subst-all subst t1))))]
+       [_ #f])]           
+    [(Union? t1) (union-map (lambda (e) (restrict e t2)) t1)]
+    [(Mu? t1)
+     (restrict (unfold t1) t2)]
+    [(Mu? t2) (restrict t1 (unfold t2))]
+    [(subtype t2 t1) t2] ;; we don't actually want this - want something that's a part of t1
+    [(not (overlap t1 t2)) (Un)] ;; there's no overlap, so the restriction is empty
+    [else t2] ;; t2 and t1 have a complex relationship, so we punt
+    ))
+
+;(trace restrict)
+
+;; also not yet correct
+;; produces old without the contents of rem
+(define (*remove old rem)
+  (define initial
+    (if (subtype old rem) 
+        (Un) ;; the empty type
+        (match (list old rem)
+          [(list (or (App: _ _ _) (Name: _)) t)
+           ;; must be different, since they're not subtypes
+           ;; and n must refer to a distinct struct type
+           old]          
+          [(list (Union: l) rem)
+           (apply Un (map (lambda (e) (*remove e rem)) l))]                  
+          [(list (? Mu? old) t) (*remove (unfold old) t)]
+          [(list (Poly: vs b) t) (make-Poly vs (*remove b rem))]
+          [_ old])))
+  (if (subtype old initial) old initial))
+
+;(trace *remove)
+;(trace restrict)
+
+
diff --git a/collects/typed-scheme/private/rep-utils.ss b/collects/typed-scheme/private/rep-utils.ss
new file mode 100644
index 0000000000..19939a6358
--- /dev/null
+++ b/collects/typed-scheme/private/rep-utils.ss
@@ -0,0 +1,164 @@
+#lang scheme/base
+
+(require mzlib/struct 
+         mzlib/plt-match
+         syntax/boundmap
+         "planet-requires.ss"
+         "free-variance.ss"
+         "utils.ss"
+         "interning.ss"
+         mzlib/etc
+         (for-syntax 
+          scheme/base
+          syntax/struct
+          syntax/stx
+          "utils.ss"))
+
+(provide == dt de print-type* print-effect* Type Type? Effect Effect? defintern hash-id Type-seq Effect-seq)
+
+
+
+;; hash table for defining folds over types
+(define-values-for-syntax (type-name-ht effect-name-ht)
+  (values (make-hash-table) (make-hash-table)))
+
+(provide (for-syntax type-name-ht effect-name-ht))
+
+
+;; all types are Type?
+(define-struct/printer Type (seq) (lambda (a b c) ((unbox print-type*) a b c)))
+
+(define-struct/printer Effect (seq) (lambda (a b c) ((unbox print-effect*) a b c)))
+
+
+
+
+
+;; type/effect definition macro
+
+(define-for-syntax type-rec-id #'type-rec-id)
+(define-for-syntax effect-rec-id #'effect-rec-id)
+(define-for-syntax fold-target #'fold-target)
+
+(provide (for-syntax type-rec-id effect-rec-id fold-target))
+
+(define-syntaxes (dt de)
+  (let ()
+    (define (parse-opts opts stx)
+      (let loop ([provide? #t] [intern? #f] [frees #t] [fold-rhs #f] [opts opts])
+        (cond 
+          [(null? opts) (values provide? intern? frees fold-rhs)]
+          [(eq? '#:no-provide (syntax-e (stx-car opts)))
+           (loop #f intern? frees fold-rhs (cdr opts))]
+          [(eq? '#:no-frees (syntax-e (stx-car opts)))
+           (loop #f intern? #f fold-rhs (cdr opts))]
+          [(not (and (stx-pair? opts) (stx-pair? (stx-car opts))))
+           (raise-syntax-error #f "bad options" stx)]
+          [(eq? '#:intern (syntax-e (stx-car (car opts))))
+           (loop provide? (stx-car (stx-cdr (car opts))) frees fold-rhs (cdr opts))]
+          [(eq? '#:frees (syntax-e (stx-car (car opts))))
+           (loop provide? intern? (stx-cdr (car opts)) fold-rhs (cdr opts))]
+          [(eq? '#:fold-rhs (syntax-e (stx-car (car opts))))
+           (loop provide? intern? frees (stx-cdr (car opts)) (cdr opts))]
+          [else (raise-syntax-error #f "bad options" stx)])))
+    (define (mk par ht-stx)        
+      (lambda (stx)          
+        (syntax-case stx ()
+          [(dform nm flds . opts)
+           (let*-values ([(provide? intern? frees fold-rhs) (parse-opts (syntax->list #'opts) #'opts)]
+                         [(kw) (string->keyword (symbol->string (syntax-e #'nm)))])
+             (with-syntax* 
+                 ([ex (id #'nm #'nm ":")]
+                  [kw-stx kw]
+                  [parent par]
+                  [(s:ty maker pred acc ...) (build-struct-names #'nm (syntax->list #'flds) #f #t #'nm)]
+                  [(flds* ...) #'flds]
+                  [*maker (id #'nm "*" #'nm)]
+                  [**maker (id #'nm "**" #'nm)]
+                  [ht-stx ht-stx]
+                  [bfs-fold-rhs (cond [(and fold-rhs (eq? (syntax-e (stx-car fold-rhs)) '#:base))
+                                       #`(lambda (tr er) #,fold-target)]
+                                      [(and fold-rhs (stx-pair? fold-rhs))
+                                       (with-syntax ([fr (stx-car fold-rhs)])
+                                         #'(lambda (tr er) 
+                                             #'fr))]
+                                      [fold-rhs (raise-syntax-error fold-rhs "something went wrong")]
+                                      [else #'(lambda (type-rec-id effect-rec-id) #`(*maker (#,type-rec-id flds*) ...))])]
+                  [provides (if provide? 
+                                #`(begin 
+                                    (provide ex pred acc ...)
+                                    (provide (rename-out [*maker maker])))
+                                #'(begin))]
+                  [intern (cond 
+                            [(syntax? intern?)
+                             #`(defintern (**maker . flds) maker #,intern?)]                                        
+                            [(null? (syntax-e #'flds))
+                             #'(defintern (**maker . flds) maker #f)]
+                            [(stx-null? (stx-cdr #'flds)) #'(defintern (**maker . flds) maker . flds)]
+                            [else #'(defintern (**maker . flds) maker (list . flds))])]
+                  [frees (cond
+                           [(not frees) #'(begin)]
+                           ;; we know that this has no free vars
+                           [(and (pair? frees) (syntax? (car frees)) (not (syntax-e (car frees))))
+                            (syntax/loc stx
+                              (define (*maker . flds)
+                                (define v (**maker . flds)) 
+                                #;(printf  "~a entered in #f case~n" '*maker)
+                                (unless-in-table 
+                                 var-table v
+                                 (hash-table-put! var-table v empty-hash-table)
+                                 (hash-table-put! index-table v empty-hash-table))
+                                v))]
+                           ;; we provided an expression each for calculating the free vars and free idxs
+                           ;; this should really be 2 expressions, one for each kind
+                           [(and (pair? frees) (pair? (cdr frees)))
+                            (quasisyntax/loc
+                                stx
+                              (define (*maker . flds)
+                                (define v (**maker . flds))
+                                #;(printf  "~a entered in expr case ~n~a~n~a ~n" '*maker '#,(car frees) '#,(cadr frees))
+                                #,
+                                (quasisyntax/loc (car frees)
+                                  (unless-in-table 
+                                   var-table v
+                                   (hash-table-put! var-table v #,(car frees))
+                                   (hash-table-put! index-table v #,(cadr frees))))
+                                #;(printf  "~a exited in expr case~n" '*maker)
+                                v))]                                       
+                           [else 
+                            (let 
+                                ([combiner 
+                                  (lambda (f flds)
+                                    (syntax-case flds ()
+                                      [() #'empty-hash-table]
+                                      [(e) #`(#,f e)]
+                                      [(e ...) #`(combine-frees (list (#,f e) ...))]))])
+                              (quasisyntax/loc stx
+                                (define (*maker . flds)
+                                  (define v (**maker . flds))
+                                  #;(printf  "~a entered in default case~n" '*maker)
+                                  (unless-in-table 
+                                   var-table v
+                                   (define fvs #,(combiner #'free-vars* #'flds))
+                                   (define fis #,(combiner #'free-idxs* #'flds))
+                                   (hash-table-put! var-table v fvs)
+                                   (hash-table-put! index-table v fis))
+                                  v)))])])
+               #'(begin
+                   (define-struct (nm parent) flds #:inspector #f)
+                   (define-match-expander ex
+                     (lambda (s)
+                       (... 
+                        (syntax-case s ()
+                          [(__ fs ...) (syntax/loc s (struct nm (_ fs ...)))]))))
+                   (begin-for-syntax
+                     (hash-table-put! ht-stx 'kw-stx (list #'ex #'flds bfs-fold-rhs)))
+                   intern
+                   provides
+                   frees)))])))
+    (values (mk #'Type #'type-name-ht) (mk #'Effect #'effect-name-ht))))
+
+
+
+
+
diff --git a/collects/typed-scheme/private/require-contract.ss b/collects/typed-scheme/private/require-contract.ss
new file mode 100644
index 0000000000..c6157919ef
--- /dev/null
+++ b/collects/typed-scheme/private/require-contract.ss
@@ -0,0 +1,40 @@
+#lang scheme/base
+
+(require scheme/contract (for-syntax scheme/base syntax/kerncase))
+(provide require/contract define-ignored)
+
+(define-syntax (define-ignored stx)
+  (syntax-case stx ()
+    [(_ name expr)
+     (syntax-case (local-expand/capture-lifts #'expr 'expression 
+                                              (list #'define-values))
+       (begin define-values)
+       [(begin (define-values (n) e) e*)
+        #'(begin (define-values (n) e)
+                 (define name e*))]
+       [e #'(define name e)])]))
+
+(define-syntax (require/contract stx)
+  (syntax-case stx ()
+    [(require/contract nm cnt lib)
+     #`(begin (require (only-in lib [nm tmp]))     
+              (define-ignored nm (contract cnt tmp '#,(syntax->datum #'nm) 'never-happen #'#,stx)))]))
+#|
+(module a mzscheme
+  (provide x)
+  (define (x a) 'hi))
+
+(module z mzscheme
+  (require require-contract)
+  
+  (require (lib "contract.ss"))
+  
+  (define-struct b (X Y))
+  
+  (require/contract x (b? . -> . b?) a )
+  
+  (x 'no)
+  )
+
+(require z)
+|#
diff --git a/collects/typed-scheme/private/resolve-type.ss b/collects/typed-scheme/private/resolve-type.ss
new file mode 100644
index 0000000000..b07bf88d92
--- /dev/null
+++ b/collects/typed-scheme/private/resolve-type.ss
@@ -0,0 +1,79 @@
+#lang scheme/base
+
+(require "type-rep.ss"  "type-name-env.ss" "tc-utils.ss"
+         "type-utils.ss" 
+         mzlib/plt-match
+         mzlib/trace)
+
+(provide resolve-name resolve-app needs-resolving? resolve-once)
+
+(define (resolve-name t)
+  (match t
+    [(Name: n) (lookup-type-name n)]
+    [_ (int-err "resolve-name: not a name ~a" t)]))
+
+(define (resolve-app rator rands stx)
+  (parameterize ([current-orig-stx stx])
+    (match rator
+      [(Poly: _ _)
+       (instantiate-poly rator rands)]
+      [(Name: _) (resolve-app (resolve-name rator) rands stx)]
+      [(Mu: _ _) (resolve-app (unfold rator) rands)]
+      [(App: r r* s) (resolve-app (resolve-app r r* s) rands)]
+      [_ (tc-error "resolve-app: not a proper operator ~a" rator)])))
+
+(define (needs-resolving? t)
+  (or (Mu? t) (App? t) (Name? t)))
+
+(define (resolve-once t)
+  (match t
+    [(Mu: _ _) (unfold t)]
+    [(App: r r* s) (resolve-app r r* s)]
+    [(Name: _) (resolve-name t)]))
+
+#|
+
+(define (resolve-tc-result tcr)
+  (match tcr
+    [(tc-result: t e1s e2s)
+     (ret (resolve-type t) (map resolve-effect e1s) (map resolve-effect e2s))]))
+
+(define (resolve-effect* e)
+  (effect-case resolve-type resolve-effect e))
+
+
+
+(define (resolve-type* t)
+  (define (int t)
+    (type-case resolve-type t
+               [#:Name stx (lookup-type-name stx)]
+               [#:Poly #:matcher Poly: names body (make-Poly names (resolve-type body))]
+               [#:Mu #:matcher Mu: name body (make-Mu name (resolve-type body))]
+               [#:App rator rands stx
+                      (let ([rator (resolve-type rator)]
+                            [rands (map resolve-type rands)])
+                        (unless (Poly? rator)
+                          (tc-error/stx stx "Cannot apply non-polymorphic type: ~a, arguments were: ~a" rator rands))
+                        (instantiate-poly rator rands))]))             
+  (let loop ([t (int t)])
+    (if (or (Name? t) (App? t))
+        (loop (resolve-type t))
+        t)))
+
+(define table (make-hash-table))
+
+(define (resolve-type t)
+  (hash-table-get table t
+                  (lambda () (let ([v (resolve-type* t)])
+                               (hash-table-put! table t v)
+                               v))))
+
+(define (resolve-effect t)
+  (hash-table-get table t
+                  (lambda () (let ([v (resolve-effect* t)])
+                               (hash-table-put! table t v)
+                               v))))
+
+;(trace resolve-type)
+
+|#
\ No newline at end of file
diff --git a/collects/typed-scheme/private/signatures.ss b/collects/typed-scheme/private/signatures.ss
new file mode 100644
index 0000000000..19812bf322
--- /dev/null
+++ b/collects/typed-scheme/private/signatures.ss
@@ -0,0 +1,42 @@
+(module signatures mzscheme
+  (require (lib "unit.ss"))
+  (provide (all-defined))
+  
+  ;; cycle 1
+  
+  (define-signature type-printer^
+    (print-type has-name print-effect)) ;; done
+  
+  (define-signature infer^
+    (unify1 fv fv/list unfold)) ;; done 
+   
+  (define-signature subst^
+    (subst subst-all)) ;; done
+  
+  (define-signature type-equal^
+    (type-equal? type-compare type<? rename tc-result-equal?)) ;; done
+  
+  ;; cycle 2
+  
+  (define-signature typechecker^
+    (type-check tc-toplevel-form))
+  
+  (define-signature tc-expr^
+    (tc-expr tc-expr/check check-below tc-literal tc-exprs tc-exprs/check tc-expr/t #;check-expr))
+  
+  (define-signature check-subforms^
+    (check-subforms/ignore check-subforms/with-handlers check-subforms/with-handlers/check))
+  
+  (define-signature tc-if^
+    (tc/if-onearm tc/if-twoarm tc/if-onearm/check tc/if-twoarm/check))
+  
+  (define-signature tc-lambda^
+    (tc/lambda tc/lambda/check tc/rec-lambda/check))
+  
+  (define-signature tc-app^
+    (tc/app tc/app/check tc/funapp))
+  
+  (define-signature tc-let^
+    (tc/let-values tc/letrec-values tc/let-values/check tc/letrec-values/check))
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/subtype.ss b/collects/typed-scheme/private/subtype.ss
new file mode 100644
index 0000000000..dcda390b32
--- /dev/null
+++ b/collects/typed-scheme/private/subtype.ss
@@ -0,0 +1,272 @@
+#lang scheme/base
+
+(require "type-rep.ss" "unify.ss" "type-utils.ss"
+         "tc-utils.ss"
+         "effect-rep.ss"
+         "type-comparison.ss"
+         "resolve-type.ss"
+         "type-name-env.ss"
+         mzlib/plt-match
+         mzlib/trace)
+
+
+
+;; exn representing failure of subtyping
+;; s,t both types
+
+(define-struct (exn:subtype exn:fail) (s t))
+#;
+(define-values (fail-sym exn:subtype?)
+  (let ([sym (gensym)])
+    (values sym (lambda (s) (eq? s sym)))))
+
+;; inference failure - masked before it gets to the user program
+(define-syntax fail!
+  (syntax-rules ()
+    [(_ s t) #;(raise fail-sym)
+             (raise (make-exn:subtype "subtyping failed" (current-continuation-marks) s t))
+             #;(error "inference failed" s t)]))
+
+
+;; data structures for remembering things on recursive calls
+(define (empty-set) '())  
+
+(define current-seen (make-parameter (empty-set)))
+
+(define (seen-before s t) (cons (Type-seq s) (Type-seq t)))
+(define (remember s t A) (cons (seen-before s t) A))
+(define (seen? s t) (member (seen-before s t) (current-seen)))
+
+
+;; is s a subtype of t?
+;; type type -> boolean
+(define (subtype s t)
+  (with-handlers
+      ([exn:subtype? (lambda _ #f)])
+    (subtype* (current-seen) s t)))
+
+;; are all the s's subtypes of all the t's?
+;; [type] [type] -> boolean
+(define (subtypes s t)
+  (with-handlers
+      ([exn:subtype? (lambda _ #f)])
+    (subtypes* (current-seen) s t)))
+
+;; subtyping under constraint set, but produces boolean result instead of raising exn
+;; List[(cons Number Number)] type type -> maybe[List[(cons Number Number)]]
+(define (subtype*/no-fail A s t)
+  (with-handlers
+      ([exn:subtype? (lambda _ #f)])
+    (subtype* A s t)))
+
+;; type type -> (does not return)
+;; subtying fails
+#;
+(define (fail! s t) (raise (make-exn:subtype "subtyping failed" (current-continuation-marks) s t)))
+
+;; check subtyping for two lists of types
+;; List[(cons Number Number)] listof[type] listof[type] -> List[(cons Number Number)]
+(define (subtypes* A ss ts)
+  (cond [(and (null? ss) (null? ts) A)]
+        [(or (null? ss) (null? ts)) (fail! ss ts)]
+        [(subtype* A (car ss) (car ts)) 
+         =>
+         (lambda (A*) (subtypes* A* (cdr ss) (cdr ts)))]
+        [else (fail! (car ss) (car ts))]))
+
+;; check if s is a supertype of any element of ts
+(define (supertype-of-one/arr A s ts)
+  (ormap (lambda (e) (arr-subtype*/no-fail A e s)) ts))
+
+(define (sub-eff e1 e2)
+  (match (list e1 e2)
+    [(list e e) #t]
+    [(list (Latent-Restrict-Effect: t) (Latent-Restrict-Effect: t*))
+     (and (subtype t t*)
+          (subtype t* t))]
+    [(list (Latent-Remove-Effect: t) (Latent-Remove-Effect: t*))
+     (and (subtype t t*)
+          (subtype t* t))]
+    [else #f]))
+
+;(trace sub-eff)
+
+
+;; simple co/contra-variance for ->
+(define (arr-subtype*/no-fail A0 s t)
+  (with-handlers
+      ([exn:subtype? (lambda _ #f)])
+    (match (list s t)
+      ;; top for functions is above everything
+      [(list _ (top-arr:)) A0]
+      [(list (arr: s1 s2 #f thn-eff els-eff) (arr: t1 t2 #f (or '() thn-eff) (or '() els-eff)))
+       (let ([A1 (subtypes* A0 t1 s1)])
+         (subtype* A1 s2 t2))]
+      [(list (arr: s1 s2 s3 thn-eff els-eff) (arr: t1 t2 t3 thn-eff* els-eff*))
+       (unless 
+           (or (and (null? thn-eff*) (null? els-eff*))
+               (and (effects-equal? thn-eff thn-eff*)
+                    (effects-equal? els-eff els-eff*))
+               (and (andmap sub-eff thn-eff thn-eff*)
+                    (andmap sub-eff els-eff els-eff*)))
+         (fail! s t))
+       ;; either the effects have to be the same, or the supertype can't have effects
+       (let ([A (subtypes*/varargs A0 t1 s1 s3)])
+         (if (not t3)
+             (subtype* A s2 t2)
+             (let ([A1 (subtype* A t3 s3)])
+               (subtype* A1 s2 t2))))]
+      [else 
+       (fail! s t)])))
+
+(define (subtypes/varargs args dom rst)
+  (with-handlers
+      ([exn:subtype? (lambda _ #f)])      
+    (subtypes*/varargs (empty-set) args dom rst)))
+
+(define (subtypes*/varargs A0 argtys dom rst)
+  (let loop-varargs ([dom dom] [argtys argtys] [A A0])
+    (cond
+      [(and (null? dom) (null? argtys)) A]
+      [(null? argtys) (fail! argtys dom)]
+      [(and (null? dom) rst)
+       (cond [(subtype* A (car argtys) rst) => (lambda (A) (loop-varargs dom (cdr argtys) A))]
+             [else (fail! (car argtys) rst)])]
+      [(null? dom) (fail! argtys dom)]
+      [(subtype* A (car argtys) (car dom)) => (lambda (A) (loop-varargs (cdr dom) (cdr argtys) A))]
+      [else (fail! (car argtys) (car dom))])))
+
+;(trace subtypes*/varargs)
+
+
+;; the algorithm for recursive types transcribed directly from TAPL, pg 305
+;; List[(cons Number Number)] type type -> List[(cons Number Number)]
+;; potentially raises exn:subtype, when the algorithm fails
+;; is s a subtype of t, taking into account constraints A
+(define (subtype* A s t)
+  (parameterize ([match-equality-test type-equal?]
+                 [current-seen A])
+    (if (seen? s t)
+        A
+        (let* ([A0 (remember s t A)])
+          (parameterize ([current-seen A0])
+            #;(match t
+              [(Name: n) (when (eq? 'heap (syntax-e n))
+                             (trace subtype*))]
+              [_ #f])
+            (match (list s t)
+              ;; subtyping is reflexive
+              [(list t t) A0]              
+              ;; univ is top
+              [(list _ (Univ:)) A0]
+              ;; (Un) is bot
+              [(list _ (Union: (list))) (fail! s t)]
+              [(list (Union: (list)) _) A0]
+              ;; value types              
+              [(list (Value: v1) (Value: v2)) (=> unmatch) (if (equal? v1 v2) A0 (unmatch))]
+              ;; integers are numbers too
+              [(list (Base: 'Integer) (Base: 'Number)) A0]
+              ;; values are subtypes of their "type"
+              [(list (Value: (? integer? n)) (Base: 'Integer)) A0]
+              [(list (Value: (? number? n)) (Base: 'Number)) A0]
+              [(list (Value: (? boolean? n)) (Base: 'Boolean)) A0]
+              [(list (Value: (? symbol? n)) (Base: 'Symbol)) A0]
+              [(list (Value: (? string? n)) (Base: 'String)) A0]
+              ;; tvars are equal if they are the same variable
+              [(list (F: t) (F: t*)) (if (eq? t t*) A0 (fail! s t))]
+              ;; case-lambda
+              [(list (Function: arr1) (Function: arr2))
+               (when (null? arr1) (fail! s t))
+               (let loop-arities ([A* A0]
+                                  [arr2 arr2])
+                 (cond 
+                   [(null? arr2) A*]
+                   [(supertype-of-one/arr A* (car arr2) arr1) => (lambda (A) (loop-arities A (cdr arr2)))]
+                   [else (fail! s t)]))]
+              ;; recur structurally on pairs
+              [(list (Pair: a d) (Pair: a* d*))
+               (let ([A1 (subtype* A0 a a*)])
+                 (and A1 (subtype* A1 d d*)))]
+              ;; quantification over two types preserves subtyping
+              [(list (Poly: ns b1) (Poly: ms b2)) 
+               (=> unmatch)
+               (unless (= (length ns) (length ms)) 
+                 (unmatch))
+               ;(printf "Poly: ~n~a ~n~a~n" b1 (subst-all (map list ms (map make-F ns)) b2))
+               (subtype* A0 b1 (subst-all (map list ms (map make-F ns)) b2))]
+              ;; use unification to see if we can use the polytype here
+              [(list (Poly: vs b) s)
+               (=> unmatch)
+               (if (unify1 s b) A0 (unmatch))]
+              [(list s (Poly: vs b))
+               (=> unmatch)
+               (if (null? (fv b)) (subtype* A0 s b) (unmatch))]
+              ;; names are compared for equality:
+              [(list (Name: n) (Name: n*))
+               (=> unmatch)
+               (if (free-identifier=? n n*)
+                   A0
+                   (unmatch))]
+              ;; just unfold the recursive types
+              [(list _ (? Mu?)) (subtype* A0 s (unfold t))]
+              [(list (? Mu?) _) (subtype* A0 (unfold s) t)]
+              ;; for unions, we check the cross-product
+              [(list (Union: es) t) (and (andmap (lambda (elem) (subtype* A0 elem t)) es) A0)]
+              [(list s (Union: es)) (and (ormap (lambda (elem) (subtype*/no-fail A0 s elem)) es) A0)]
+              ;; subtyping on immutable structs is covariant
+              [(list (Struct: nm _ flds #f) (Struct: nm _ flds* #f))
+               (subtypes* A0 flds flds*)]
+              [(list (Struct: nm _ flds proc) (Struct: nm _ flds* proc*))
+               (subtypes* A0 (cons proc flds) (cons proc* flds*))]
+              ;; subtyping on structs follows the declared hierarchy
+              [(list (Struct: nm (? Type? parent) flds proc) other) 
+               ;(printf "subtype - hierarchy : ~a ~a ~a~n" nm parent other)
+               (subtype* A0 parent other)]
+              ;; applications and names are structs too
+              [(list (App: (Name: n) args _) other)
+               (let ([t (lookup-type-name n)])
+                 (unless (Type? t)                     
+                   (fail! s t))
+                 #;(printf "subtype: app-name: name: ~a type: ~a other: ~a ~ninst: ~a~n" (syntax-e n) t other 
+                           (instantiate-poly t args))
+                 (let ([v (subtype* A0 (instantiate-poly t args) other)])                    
+                   #;(printf "val: ~a~n"  v)
+                   v))]
+              [(list (Name: n) other)
+               (let ([t (lookup-type-name n)])
+                 ;(printf "subtype: name: ~a ~a ~a~n" (syntax-e n) t other)
+                 (if (Type? t)                     
+                     (subtype* A0 t other)
+                     (fail! s t)))]
+              ;; Promises are covariant
+              [(list (Struct: 'Promise _ (list t) _) (Struct: 'Promise _ (list t*) _)) (subtype* A0 t t*)]
+              ;; subtyping on values is pointwise
+              [(list (Values: vals1) (Values: vals2)) (subtypes* A0 vals1 vals2)]
+              ;; single values shouldn't actually happen, but they're just like the type
+              [(list t (Values: (list t*))) (int-err "BUG - singleton values type~a" (make-Values (list t*)))]
+              [(list (Values: (list t)) t*) (int-err "BUG - singleton values type~a" (make-Values (list t)))]
+              ;; subtyping on other stuff
+              [(list (Syntax: t) (Syntax: t*))
+               (subtype* A0 t t*)]
+              [(list (Instance: t) (Instance: t*))
+               (subtype* A0 t t*)]
+              ;; otherwise, not a subtype
+              [_ (fail! s t) (printf "failed")]))))))
+
+(define (type-compare? a b)
+  (and (subtype a b) (subtype b a)))
+
+(provide subtype type-compare? subtypes/varargs subtypes)
+
+;(trace subtype*)
+;(trace supertype-of-one/arr)
+;(trace arr-subtype*/no-fail)
+;(trace subtype-of-one)
+;(trace subtype*/no-fail)
+;(trace subtypes*)
+;(trace subtype)
+
+;(subtype (-> Univ B) (-> Univ Univ))
+;(subtype (make-poly '(a) (make-tvar 'a)) (make-lst N))
+
+
diff --git a/collects/typed-scheme/private/syntax-traversal.ss b/collects/typed-scheme/private/syntax-traversal.ss
new file mode 100644
index 0000000000..e2cfe31685
--- /dev/null
+++ b/collects/typed-scheme/private/syntax-traversal.ss
@@ -0,0 +1,59 @@
+#lang scheme/base
+
+(require mzlib/trace)
+
+;; from Eli
+
+(provide (all-defined-out))
+
+;; -------------------- utilities
+
+(define (pull-from-syntax stx . locs)
+  (let loop ([stx stx] [locs locs])
+    (if (null? locs)
+      stx
+      (loop (list-ref (syntax->list stx) (car locs)) (cdr locs)))))
+
+(define (syntax-loc stx) (list (syntax-position stx) (syntax-span stx)))
+
+;; -------------------- the real stuff
+
+;; Look for `lookfor' in `enclosing', return chain of syntaxes from
+;; the innermost out of only syntaxes with the given src, returns #f
+;; if it can't find it.
+(define (enclosing-syntaxes-with-source enclosing lookfor src)
+  (let loop ([r '()] [stx enclosing])
+    (let* ([r (if (and (syntax? stx) (eq? src (syntax-source stx)))
+                (cons stx r)
+                r)]
+           [loop (lambda (stx) (loop r stx))])
+      (if (eq? stx lookfor)
+        r
+        (let ([stx (if (syntax? stx) (syntax-e stx) stx)])
+          (and (pair? stx)
+               (or (loop (car stx)) (loop (cdr stx)))))))))
+
+
+
+;; Look for (the outermost) syntax in `orig' that has the same
+;; location as `lookfor' which is coming from the expanded `orig',
+;; given in `expanded'.
+(define (look-for-in-orig orig expanded lookfor)
+  (define src (syntax-source orig))
+  ;; we just might get a lookfor that is already in the original
+  (if (eq? src (syntax-source lookfor))
+    lookfor
+    (let ([enclosing (enclosing-syntaxes-with-source expanded lookfor src)]
+          [syntax-locs (make-hash-table 'equal)])
+      ;; find all syntax locations in original code
+      (let loop ([stx orig])
+        (when (syntax? stx) (hash-table-put! syntax-locs (syntax-loc stx) stx))
+        (let ([stx (if (syntax? stx) (syntax-e stx) stx)])
+          (when (pair? stx) (loop (car stx)) (loop (cdr stx)))))
+      ;; look for some enclosing expression
+      (and enclosing
+           (ormap (lambda (enc) (hash-table-get syntax-locs (syntax-loc enc) #f))
+                  enclosing)))))
+
+;(trace look-for-in-orig)
+
diff --git a/collects/typed-scheme/private/tables.ss b/collects/typed-scheme/private/tables.ss
new file mode 100644
index 0000000000..6d52dd436e
--- /dev/null
+++ b/collects/typed-scheme/private/tables.ss
@@ -0,0 +1,42 @@
+#lang scheme/base
+
+(require mzlib/plt-match)
+
+(provide (all-defined-out))
+
+;; a table is represented by an association list, (cons key value)
+
+;; alist->eq : alist -> table
+(define (alist->eq l) l)
+
+;; to-sexp : table -> Listof(List k v)
+(define (to-sexp t)
+  (map (match-lambda [(cons k v) (list k v)]) t))
+
+;; union/value : table(k,v) table(k,v) (v v -> v) -> table(k,v)
+(define (union/value t1 t2 f)
+  (define ks1 (map car t1))
+  (define ks2 (map car t2))
+  ;; everything but the common ones
+  (define t1* (filter (match-lambda [(cons k v) (not (memq k ks2))]) t1))
+  (define t2* (filter (match-lambda [(cons k v) (not (memq k ks1))]) t2))
+  (define pre-result (append t1* t2*))
+  ;; the common ones
+  (define *t1 (filter (match-lambda [(cons k v) (memq k ks2)]) t1))
+  (define *t2 (filter (match-lambda [(cons k v) (memq k ks1)]) t2))
+  (define merged (map (match-lambda [(cons k v1)
+                                     (let ([v2 (cdr (assq k *t2))])
+                                       (cons k (f v1 v2)))])
+                      *t1))
+  (append pre-result merged))
+
+(define (make-eq) null)
+
+(define (lookup k t) 
+  (cond [(assq k t) => cdr]
+        [else #f]))
+
+(define (insert k v t)
+  (cons (cons k v) t))
+
+
diff --git a/collects/typed-scheme/private/tc-app-unit.ss b/collects/typed-scheme/private/tc-app-unit.ss
new file mode 100644
index 0000000000..21c33a2b9b
--- /dev/null
+++ b/collects/typed-scheme/private/tc-app-unit.ss
@@ -0,0 +1,462 @@
+#lang scheme/unit
+
+(require "signatures.ss"
+         (lib "plt-match.ss")
+         (lib "list.ss")
+         (prefix-in 1: srfi/1)
+         "type-rep.ss"
+         "effect-rep.ss"
+         "tc-utils.ss"
+         "subtype.ss"
+         "unify.ss"
+         "infer.ss"
+         "union.ss"
+         "type-utils.ss"
+         "type-effect-convenience.ss"
+         "type-effect-printer.ss"
+         "type-annotation.ss"
+         "resolve-type.ss"
+         (only-in scheme/private/class-internal make-object do-make-object)
+         (lib "pretty.ss")
+         (lib "trace.ss")
+         (lib "kerncase.ss" "syntax"))
+
+(require (for-template (lib "plt-match.ss") "internal-forms.ss" scheme/base 
+                       (only-in scheme/private/class-internal make-object do-make-object)))
+(require (for-syntax (lib "plt-match.ss") "internal-forms.ss"))
+
+
+(import tc-expr^ tc-lambda^)
+(export tc-app^)
+
+;; comparators that inform the type system
+(define (comparator? i)
+  (or (free-identifier=? i #'eq?)
+      (free-identifier=? i #'equal?)
+      (free-identifier=? i #'eqv?)
+      (free-identifier=? i #'=)
+      (free-identifier=? i #'string=?)))
+
+;; typecheck eq? applications
+;; identifier identifier expression expression expression
+;; identifier expr expr expr expr -> tc-result
+(define (tc/eq comparator v1 v2)
+  (define (e? i) (free-identifier=? i comparator))
+  (define (do id val)
+    (define-syntax alt (syntax-rules () [(_ nm pred ...) 
+                                         (and (e? #'nm) (or (pred val) ...))]))
+    (if (or (alt symbol=? symbol?)
+            (alt string=? string?)
+            (alt = number?)
+            (alt eq? boolean? keyword? symbol?)
+            (alt eqv? boolean? keyword? symbol? number?)
+            (alt equal? (lambda (x) #t)))
+        (values (list (make-Restrict-Effect (-val val) id))
+                (list (make-Remove-Effect (-val val) id)))          
+        (values (list) (list))))
+  (match (list (tc-expr v1) (tc-expr v2))
+    [(list (tc-result: id-t (list (Var-True-Effect: id1)) (list (Var-False-Effect: id2))) (tc-result: (Value: val)))
+     (do id1 val)]
+    [(list (tc-result: (Value: val)) (tc-result: id-t (list (Var-True-Effect: id1)) (list (Var-False-Effect: id2))))
+     (do id1 val)]
+    [_ (values (list) (list))]))
+
+
+;; typecheck an application:
+;; arg-types: the types of the actual parameters
+;; arg-effs: the effects of the arguments
+;; dom-types: the types of the function's fixed arguments
+;; rest-type: the type of the functions's rest parameter, or #f
+;; latent-eff: the latent effect of the function
+;; arg-stxs: the syntax for each actual parameter, for error reporting
+;; [Type] [Type] Maybe[Type] [Syntax] -> Effect  
+(define (tc-args arg-types arg-thn-effs arg-els-effs dom-types rest-type latent-thn-eff latent-els-eff arg-stxs)
+  (define (var-true-effect-v e) (match e
+                                  [(Var-True-Effect: v) v]))
+  (define (var-false-effect-v e) (match e
+                                   [(Var-False-Effect: v) v]))
+  ;; special case for predicates:
+  (if (and (not (null? latent-thn-eff))
+           (not (null? latent-els-eff))
+           (not rest-type)
+           ;(printf "got to =~n")
+           (= (length arg-types) (length dom-types) 1)             
+           ;(printf "got to var preds~n")
+           (= (length (car arg-thn-effs)) (length (car arg-els-effs)) 1)
+           (Var-True-Effect? (caar arg-thn-effs)) ;; thn-effs is a list for each arg
+           (Var-False-Effect? (caar arg-els-effs)) ;; same with els-effs
+           #;(printf "got to mi= ~a ~a ~n~a ~a~n" 
+                     (var-true-effect-v (caar arg-thn-effs)) (var-true-effect-v (caar arg-els-effs))
+                     (syntax-e (var-true-effect-v (caar arg-thn-effs))) (syntax-e (var-false-effect-v (caar arg-els-effs))))
+           (free-identifier=? (var-true-effect-v (caar arg-thn-effs))
+                              (var-false-effect-v (caar arg-els-effs)))
+           (subtype (car arg-types) (car dom-types)))
+      ;; then this was a predicate application, so we construct the appropriate type effect
+      (values (map (add-var (var-true-effect-v (caar arg-thn-effs))) latent-thn-eff)
+              (map (add-var (var-true-effect-v (caar arg-thn-effs))) latent-els-eff))
+      ;; otherwise, we just ignore the effects.
+      (let loop ([args arg-types] [doms dom-types] [stxs arg-stxs] [arg-count 1])
+        (cond 
+          [(and (null? args) (null? doms)) (values null null)] ;; here, we just return the empty effect
+          [(null? args) (tc-error "Insufficient arguments to function application, expected ~a, got ~a" 
+                                  (length dom-types) (length arg-types))]
+          [(and (null? doms) rest-type)
+           (if (subtype (car args) rest-type)
+               (loop (cdr args) doms (cdr stxs) (add1 arg-count))
+               (tc-error/stx (car stxs) "Rest argument had wrong type, expected: ~a and got: ~a" rest-type (car args)))]
+          [(null? doms)
+           (tc-error "Too many arguments to function, expected ~a, got ~a" (length dom-types) (length arg-types))]
+          [(subtype (car args) (car doms))
+           (loop (cdr args) (cdr doms) (cdr stxs) (add1 arg-count))]
+          [else
+           (tc-error/stx (car stxs) "Wrong function argument type, expected ~a, got ~a for argument ~a" 
+                         (car doms) (car args) arg-count)]))))
+
+
+;(trace tc-args)
+
+(define (tc/apply f args)
+  (let* ([f-ty (tc-expr f)]
+         [arg-tys0 (map tc-expr/t (syntax->list args))])
+    ;; produces the first n-1 elements of the list, and the last element
+    (define (split l)
+      (let loop ([l l] [acc '()])
+        (if (null? (cdr l))
+            (values (reverse acc) (car l))
+            (loop (cdr l) (cons (car l) acc)))))
+    (let-values ([(arg-tys tail-ty) (split arg-tys0)])
+      (define (printable dom rst)
+        (list dom rst '..))
+      (match f-ty
+        [(tc-result: (Function: (list (arr: doms rngs rests thn-effs els-effs) ..1)))
+         (let loop ([doms* doms] [rngs* rngs] [rests* rests])
+           (cond [(null? doms*) 
+                  (if (and (not (null? doms)) (null? (cdr doms)))
+                      (tc-error
+                       "bad arguments to apply - function expected ~a fixed arguments and (Listof ~a) rest argument, given ~a"
+                       (car doms) (car rests) arg-tys0)
+                      (tc-error "no function domain matched - domains were: ~a arguments were ~a" 
+                                (map printable doms rests)
+                                arg-tys0))]
+                 [(and (subtypes arg-tys (car doms*)) (car rests*) (subtype tail-ty (make-Listof (car rests*))))
+                  (ret (car rngs*))]
+                 [else (loop (cdr doms*) (cdr rngs*) (cdr rests*))]))]                      
+        [(tc-result: (Poly: vars (Function: (list (arr: doms rngs rests thn-effs els-effs) ..1))))
+         (for-each (lambda (x) (unless (not (Poly? x))                                      
+                                 (tc-error "Polymorphic argument ~a to polymorphic function not allowed" x)))
+                   arg-tys0)
+         (let loop ([doms* doms] [rngs* rngs] [rests* rests])
+           (cond [(null? doms*)
+                  (if (= 1 (length doms))
+                      (tc-error "polymorphic function domain did not match - domain was: ~a arguments were ~a" 
+                                (car doms) arg-tys0)
+                      (tc-error "no polymorphic function domain matched - domains were: ~a arguments were ~a" doms arg-tys0))]
+                 [(and (= (length (car doms*))
+                          (length arg-tys))
+                       (infer/list (append (car doms*) (list (make-Listof (car rests*)))) arg-tys0 vars))
+                  => (lambda (substitution) 
+                       (let* ([s (lambda (t) (subst-all substitution t))]
+                              [new-doms* (append (map s (car doms*)) (list (make-Listof (s (car rests*)))))])
+                         (unless (andmap subtype arg-tys0 new-doms*)
+                           (int-err "Inconsistent substitution - arguments not subtypes")))                         
+                       (ret (subst-all substitution (car rngs*))))]
+                 [else (loop (cdr doms*) (cdr rngs*) (cdr rests*))]))]
+        [(tc-result: (Poly: vars (Function: '())))
+         (tc-error "Function has no cases")]
+        [f-ty (tc-error "Type of argument to apply is not a function type: ~n~a" f-ty)]))))
+
+(define (stringify l [between " "])
+  (define (intersperse v l)
+    (cond [(null? l) null]
+          [(null? (cdr l)) l]
+          [else (cons (car l) (cons v (intersperse v (cdr l))))]))
+  (apply string-append (intersperse between (map (lambda (s) (format "~a" s)) l))))
+
+(define (tc/funapp f-stx args-stx ftype0 argtys)
+  (match-let* ([(list (tc-result: argtypes arg-thn-effs arg-els-effs) ...) argtys])
+    (let outer-loop ([ftype ftype0] 
+                     [argtypes argtypes]
+                     [arg-thn-effs arg-thn-effs]
+                     [arg-els-effs arg-els-effs]
+                     [args args-stx])
+      (match ftype
+        [(tc-result: (and sty (Struct: _ _ _ (? Type? proc-ty))) thn-eff els-eff)
+         (outer-loop (ret proc-ty thn-eff els-eff)
+                     (cons (tc-result-t ftype0) argtypes)
+                     (cons (list) arg-thn-effs)
+                     (cons (list) arg-els-effs)
+                     #`(#,(syntax/loc f-stx dummy) #,@args))]
+        [(tc-result: (? needs-resolving? t) thn-eff els-eff)
+         (outer-loop (ret (resolve-once t) thn-eff els-eff) argtypes arg-thn-effs arg-els-effs args)]
+        [(tc-result: (Param: in out))
+         (match argtypes
+           [(list) (ret out)]
+           [(list t)
+            (if (subtype t in) 
+                (ret -Void)
+                (tc-error "Wrong argument to parameter - expected ~a and got ~a" in t))]
+           [_ (tc-error "Wrong number of arguments to parameter - expected 0 or 1, got ~a" (length argtypes))])]
+        [(tc-result: (Function: (list (arr: doms rngs rests latent-thn-effs latent-els-effs) ..1)) thn-eff els-eff)
+         (if (= 1 (length doms))
+             (let-values ([(thn-eff els-eff)
+                           (tc-args argtypes arg-thn-effs arg-els-effs (car doms) (car rests) 
+                                    (car latent-thn-effs) (car latent-els-effs) 
+                                    (syntax->list args))])
+               (ret (car rngs) thn-eff els-eff)
+               #;(if (false-effect? eff)
+                     (ret (-val #f) eff)
+                     (ret (car rngs) eff)))
+             (let loop ([doms* doms] [rngs rngs] [rests rests])
+               (cond [(null? doms*) 
+                      (tc-error "no function domain matched - domains were: ~a arguments were ~a" doms argtypes)]
+                     [(subtypes/varargs argtypes (car doms*) (car rests)) (ret (car rngs))]
+                     [else (loop (cdr doms*) (cdr rngs) (cdr rests))])))]
+        [(and rft (tc-result: (Poly: vars (Function: (list (arr: doms rngs #f thn-effs els-effs) ...)))))
+         ;(printf "Typechecking poly app~nftype:          ~a~n" ftype)
+         ;(printf "ftype again:    ~a~n" ftype)
+         ;(printf "resolved ftype: ~a : ~a~n" (equal? rft ftype) rft)
+         ;(printf "reresolving: ~a~n" (resolve-tc-result ftype))
+         ;(printf "argtypes: ~a~ndoms: ~a~n" argtypes doms)
+         (for-each (lambda (x) (unless (not (Poly? x))
+                                 (tc-error "Polymorphic argument ~a to polymorphic function not allowed" x)))
+                   argtypes)
+         (let loop ([doms* doms] [rngs* rngs])
+           (cond [(null? doms*)
+                  (match-let ([(tc-result: (Poly-names: msg-vars (Function: (list (arr: msg-doms msg-rngs #f _ _) ...)))) ftype])
+                    (if (= 1 (length doms))
+                        (tc-error "Polymorphic function could not be applied to arguments:~nExpected: ~a ~nActual: ~a" 
+                                  (car msg-doms) argtypes)
+                        (tc-error "no polymorphic function domain matched - possible domains were: ~n~a~narguments: were ~n~a"
+                                  (stringify (map stringify msg-doms) "\n") (stringify argtypes))))]
+                 [(and (= (length (car doms*))
+                          (length argtypes))
+                       (infer/list (car doms*) argtypes vars))
+                  => (lambda (substitution)
+                       (let* ([s (lambda (t) (subst-all substitution t))]
+                              [new-doms* (map s (car doms*))])
+                         (unless (andmap subtype argtypes new-doms*)
+                           (int-err "Inconsistent substitution - arguments not subtypes")))
+                       #;(printf "subst is:~a~nret is: ~a~nvars is: ~a~n" substitution (car rngs*) vars)
+                       (ret (subst-all substitution (car rngs*))))]
+                 [else (loop (cdr doms*) (cdr rngs*))]))]
+        ;; polymorphic varargs
+        [(tc-result: (Poly: vars (Function: (list (arr: dom rng rest thn-eff els-eff)))))
+         (for-each (lambda (x) (unless (not (Poly? x))                                      
+                                 (tc-error "Polymorphic argument ~a to polymorphic function not allowed" x)))
+                   argtypes)
+         (unless (<= (length dom) (length argtypes))
+           (tc-error "incorrect number of arguments to function: ~a ~a" dom argtypes))
+         (let ([substitution (infer/list/vararg dom rest argtypes vars)])
+           (if substitution
+               (let* ([s (lambda (t) (subst-all substitution t))]
+                      [new-dom (map s dom)]
+                      [new-rest (s rest)])                                  
+                 (unless (subtypes/varargs argtypes new-dom new-rest)
+                   (int-err "Inconsistent substitution - arguments not subtypes"))
+                 (ret (subst-all substitution rng)))
+               (tc-error "no polymorphic function domain matched - domain was: ~a rest type was: ~a arguments were ~a"
+                         (stringify dom) rest (stringify argtypes))))]
+        [(tc-result: (Poly: vars (Function: (list (arr: doms rngs rests thn-effs els-effs) ...))))
+         (tc-error "polymorphic vararg case-lambda application not yet supported")]
+        ;; Union of function types works if we can apply all of them
+        [(tc-result: (Union: (list (and fs (Function: _)) ...)) e1 e2)
+         (match-let ([(list (tc-result: ts) ...) (map (lambda (f) (outer-loop 
+                                                                   (ret f e1 e2) argtypes arg-thn-effs arg-els-effs args)) fs)])
+           (ret (apply Un ts)))]
+        [(tc-result: f-ty _ _) (tc-error "Cannot apply expression of type ~a, since it is not a function type" f-ty)]))))
+
+;(trace tc/funapp)
+
+(define (tc/app form) (tc/app/internal form #f))
+
+(define (tc/app/check form expected)
+  (define t (tc/app/internal form expected))
+  (check-below t expected)
+  (ret expected))
+
+;; expr id -> type or #f
+;; if there is a binding in stx of the form:
+;; (let ([x (reverse name)]) e)
+;; where x has a type annotation, return that annotation, otherwise #f
+(define (find-annotation stx name)
+  (define (find s) (find-annotation s name))
+  (define (match? b)
+    (kernel-syntax-case* b #f (reverse)
+      [[(v) (#%plain-app reverse n)]
+       (free-identifier=? name #'n)
+       (type-annotation #'v)]
+      [_ #f]))
+  (kernel-syntax-case* 
+   stx #f (reverse)
+   [(let-values (binding ...) body)
+    (cond [(ormap match? (syntax->list #'(binding ...)))]
+          [else (find #'body)])]
+   [(#%plain-app e ...) (ormap find (syntax->list #'(e ...)))]
+   [(if e1 e2 e3) (ormap find (syntax->list #'(e1 e2 e3)))]
+   [(letrec-values ([(v ...) e] ...) b)
+    (ormap find (syntax->list #'(e ... b)))]
+   [(#%plain-lambda (v ...) e)
+    (find #'e)]
+   [_ #f]))
+
+(define (matches? stx)
+  (let loop ([stx stx] [ress null] [acc*s null])
+    (syntax-case stx (#%plain-app reverse)
+      [([(res) (#%plain-app reverse acc*)] . more)
+       (loop #'more (cons #'res ress) (cons #'acc* acc*s))]
+      [rest
+       (syntax->list #'rest)
+       (begin
+         ;(printf "ress: ~a~n" (map syntax-e ress))
+         (list (reverse ress) (reverse acc*s) #'rest))]
+      [_ #f])))
+
+
+(define (tc/app/internal form expected)
+  (kernel-syntax-case* form #f 
+    (values apply not list list* call-with-values do-make-object make-object cons) ;; the special-cased functions   
+    ;; special cases for classes
+    [(#%plain-app make-object cl args ...)
+     (tc/app/internal #'(#%plain-app do-make-object cl (#%plain-app list args ...) (#%plain-app list)) expected)]     
+    [(#%plain-app do-make-object cl (#%plain-app list pos-args ...) (#%plain-app list (#%plain-app cons 'names named-args) ...))
+     (let* ([names (map syntax-e (syntax->list #'(names ...)))]
+            [name-assoc (map list names (syntax->list #'(named-args ...)))])
+       (let loop ([t (tc-expr #'cl)])
+         (match t
+           [(tc-result: (? Mu? t)) (loop (ret (unfold t)))]
+           [(tc-result: (and c (Class: pos-tys (list (and tnflds (list tnames _ _)) ...) _))) 
+            (unless (= (length pos-tys)
+                       (length (syntax->list #'(pos-args ...))))
+              (tc-error "expected ~a positional arguments, but got ~a" (length pos-tys) (length (syntax->list #'(pos-args ...)))))
+            (for-each tc-expr/check (syntax->list #'(pos-args ...)) pos-tys)
+            (for-each (lambda (n) (unless (memq n tnames)
+                                    (tc-error "unknown named argument ~a for class~nlegal named arguments are ~a" n (stringify tnames))))
+                      names)
+            (for-each (match-lambda
+                        [(list tname tfty opt?)
+                         (let ([s (cond [(assq tname name-assoc) => cadr]
+                                        [(not opt?)
+                                         (tc-error "value not provided for named init arg ~a" tname)]
+                                        [else #f])])
+                           (if s
+                               ;; this argument was present
+                               (tc-expr/check s tfty)
+                               ;; this argument wasn't provided, and was optional
+                               #f))])
+                      tnflds)
+            (ret (make-Instance c))]
+           [(tc-result: t)
+            (tc-error "expected a class value for object creation, got: ~a" t)])))]
+    [(#%plain-app do-make-object . args)
+     (int-err "bad do-make-object : ~a" (syntax->datum #'args))]
+    ;; call-with-values
+    [(#%plain-app call-with-values prod con)
+     (match-let* ([(tc-result: prod-t) (tc-expr #'prod)]
+                  [(tc-result: con-t) (tc-expr #'con)])
+       (match (list prod-t con-t)
+         [(list (Function: (list (arr: (list) vals #f _ _))) (Function: (list (arr: dom rng #f _ _))))
+          (=> unmatch)
+          (match (list vals dom)
+            [(list (Values: v) (list t ...))
+             (if (subtypes v t)
+                 (ret rng)
+                 (unmatch))]
+            [(list t1 (list t2))
+             (if (subtype t1 t2) (ret rng) (unmatch))]
+            [_ (unmatch)])]
+         [_ (tc-error "Incorrect arguments to call with values: ~a ~a" prod-t con-t)]))]
+    ;; special cases for `values'
+    [(#%plain-app values arg) (tc-expr #'arg)]
+    [(#%plain-app values . args)
+     (let ([tys (map tc-expr/t (syntax->list #'args))])
+       (ret (list->values-ty tys)))]
+    ;; special case for `list'
+    [(#%plain-app list . args)
+     (let ([tys (map tc-expr/t (syntax->list #'args))])
+       (ret (apply -lst* tys)))]
+    ;; special case for `list*'
+    [(#%plain-app list* . args)
+     (match-let* ([(list last tys-r ...) (reverse (map tc-expr/t (syntax->list #'args)))]
+                  [tys (reverse tys-r)])
+       (ret (foldr make-Pair last tys)))]
+    ;; in eq? cases, call tc/eq
+    [(#%plain-app eq? v1 v2) 
+     (and (identifier? #'eq?) (comparator? #'eq?))
+     (begin
+       ;; make sure the whole expression is type correct
+       (tc/funapp #'eq? #'(v1 v2) (tc-expr #'eq?) (map tc-expr (syntax->list #'(v1 v2))))
+       ;; check thn and els with the eq? info
+       (let-values ([(thn-eff els-eff) (tc/eq #'eq? #'v1 #'v2)])
+         (ret B thn-eff els-eff)))]
+    ;; special case for `not'
+    [(#%plain-app not arg)
+     (match (tc-expr #'arg)
+       ;; if arg was a predicate application, we swap the effects
+       [(tc-result: t thn-eff els-eff)
+        (ret B (map var->type-eff els-eff) (map var->type-eff thn-eff))])]
+    ;; special case for `apply'
+    [(#%plain-app apply f . args) (tc/apply #'f #'args)]
+    
+    ;; even more special case for match
+    [(#%plain-app 
+      (letrec-values 
+          ([(lp) (#%plain-lambda (val acc ...)
+                   (if (#%plain-app null? val*)
+                       thn
+                       els))])
+        lp*)
+      actual actuals ...)
+     (and ;(printf "got here 0:~a~n" (syntax->datum #'body))
+          expected
+          ;(printf "got here 1~n")
+          (not (andmap type-annotation (syntax->list #'(val acc ...))))
+          (free-identifier=? #'val #'val*)
+          (andmap (lambda (a) (find-annotation #'(if (#%plain-app null? val*) thn els) a))
+                  (syntax->list #'(acc ...)))
+          ;(printf "got here 2~n")
+          #;
+          (match (matches? #'lv-bindings)
+            [(list res acc* more)
+             (and
+              (andmap type-annotation res)
+              (andmap free-identifier=? (syntax->list #'(acc ...)) acc*)
+              (free-identifier=? #'lp #'lp*))]
+            [_ #f]))
+     (let* ([ts1 (tc-expr/t #'actual)]
+            [ts1 (generalize ts1)]
+            [ann-ts (map (lambda (a) (find-annotation #'(if (#%plain-app null? val*) thn els) a)) 
+                         (syntax->list #'(acc ...)))]
+            [ts (cons ts1 ann-ts)])                 
+       ;(printf "doing match case actuals:~a ann-ts: ~a~n" 
+       ;           (syntax->datum #'(actuals ...)) ann-ts)
+       ;; check that the actual arguments are ok here
+       (map tc-expr/check (syntax->list #'(actuals ...)) ann-ts)
+       ;(printf "done here ts = ~a~n" ts)
+       ;; then check that the function typechecks with the inferred types
+       (tc/rec-lambda/check form
+                            #'(val acc ...)
+                            #'((if (#%plain-app null? val*)
+                                   thn
+                                   els))
+                            #'lp
+                            ts
+                            expected)
+       (ret expected))]
+    ;; special case when argument needs inference
+    [(#%plain-app (letrec-values ([(lp) (#%plain-lambda (args ...) . body)]) lp*) . actuals)
+     (and ;(printf "special case 0 ~a~n" expected)
+          expected
+          ;(printf "special case 1~n")
+          (not (andmap type-annotation (syntax->list #'(args ...))))
+          (free-identifier=? #'lp #'lp*))
+     (let ([ts (map tc-expr/t (syntax->list #'actuals))])
+       ;(printf "special case~n")
+       (tc/rec-lambda/check form #'(args ...) #'body #'lp ts expected)
+       (ret expected))]
+    ;; default case
+    [(#%plain-app f args ...) 
+     (begin
+       ;(printf "default case~n~a~n" (syntax->datum form))
+       (tc/funapp #'f #'(args ...) (tc-expr #'f) (map tc-expr (syntax->list #'(args ...)))))]))
+  
+;(trace tc/app/internal)
diff --git a/collects/typed-scheme/private/tc-expr-unit.ss b/collects/typed-scheme/private/tc-expr-unit.ss
new file mode 100644
index 0000000000..528d6513a8
--- /dev/null
+++ b/collects/typed-scheme/private/tc-expr-unit.ss
@@ -0,0 +1,314 @@
+#lang scheme/unit
+
+
+(require (prefix-in 1: srfi/1)
+         syntax/kerncase
+         syntax/struct
+         syntax/stx
+         mzlib/etc
+         mzlib/plt-match
+         "type-contract.ss"
+         "signatures.ss"
+         "tc-structs.ss"
+         "type-utils.ss"
+         "utils.ss" ;; doesn't need tests
+         "type-rep.ss" ;; doesn't need tests
+         "unify.ss" ;; needs tests
+         "infer.ss"
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "union.ss"
+         "subtype.ss" ;; has tests
+         "internal-forms.ss" ;; doesn't need tests
+         "planet-requires.ss" ;; doesn't need tests
+         "type-env.ss" ;; maybe needs tests
+         "parse-type.ss" ;; has tests
+         "tc-utils.ss" ;; doesn't need tests
+         "type-environments.ss" ;; doesn't need tests
+         "lexical-env.ss" ;; maybe needs tests
+         "type-annotation.ss" ;; has tests
+         "type-name-env.ss" ;; maybe needs tests
+         "init-envs.ss"
+         "effect-rep.ss"
+         "mutated-vars.ss"
+         (lib "plt-match.ss")
+         scheme/private/class-internal)
+
+(require (for-template scheme/base scheme/private/class-internal))
+
+(import tc-if^ tc-lambda^ tc-app^ tc-let^ check-subforms^)
+(export tc-expr^)
+
+
+;; return the type of a literal value
+;; scheme-value -> type
+(define (tc-literal v-stx)
+  ;; find the meet of the types of a list of expressions
+  ;; list[syntax] -> type
+  (define (types-of-literals es)
+    (apply Un (map tc-literal es)))
+  (define v (syntax-e v-stx))
+  (cond
+    [(integer? v) -Integer]
+    [(number? v) N]
+    [(char? v) -Char]
+    [(boolean? v) (-val v)]
+    [(null? v) (-val null)]
+    [(symbol? v) (-val v)]
+    [(string? v) -String]
+    [(keyword? v) -Keyword]
+    [(bytes? v) -Bytes]
+    [(list? v) (-Tuple (map tc-literal v))]
+    [(vector? v) (make-Vector (types-of-literals (vector->list v)))]
+    [(pregexp? v) -PRegexp]
+    [(byte-pregexp? v) -Byte-PRegexp]
+    [(byte-regexp? v) -Byte-Regexp]
+    [(regexp? v) -Regexp]
+    [else (begin (printf "checking literal : ~a~n" v) Univ)]))
+
+;; typecheck an identifier
+;; the identifier has variable effect
+;; tc-id : identifier -> tc-result
+(define (tc-id id)
+  (let* ([ty (lookup-type/lexical id)]
+         [inst (syntax-property id 'type-inst)])
+    (when (and inst
+               (not (Poly? ty)))
+      (tc-error "Cannot instantiate non-polymorphic type ~a" ty))
+    (when (and inst
+               (not (= (length (syntax->list inst)) (Poly-n ty))))
+      (tc-error "Wrong number of type arguments to polymorphic type ~a:~nexpected: ~a~ngot: ~a"
+                ty (Poly-n ty) (length (syntax->list inst))))
+    (let ([ty* (if inst
+                   (begin
+                     (printf/log "Type Instantiation: ~a~n" (syntax-e id))
+                     (instantiate-poly ty (map parse-type (syntax->list inst))))
+                   ty)])
+      (ret ty* (list (make-Var-True-Effect id)) (list (make-Var-False-Effect id))))))
+
+;; typecheck an expression, but throw away the effect
+;; tc-expr/t : Expr -> Type
+(define (tc-expr/t e) (match (tc-expr e)
+                        [(tc-result: t) t]))
+
+(define (check-below tr1 expected)
+  (match (list tr1 expected)      
+    [(list (tc-result: t1 te1 ee1) t2)
+     (unless (subtype t1 t2)
+       (tc-error "Expected ~a, but got ~a" t2 t1))
+     (ret expected)]
+    [(list t1 t2)
+     (unless (subtype t1 t2)
+       (tc-error "Expected ~a, but got ~a" t2 t1))
+     (ret expected)]
+    [_ (error "bad arguments to check-below")]))
+
+(define (tc-expr/check form expected)
+  (parameterize ([current-orig-stx form])
+    ;(printf "form: ~a~n" (syntax-object->datum form))
+    ;; the argument must be syntax
+    (unless (syntax? form) 
+      (int-err "bad form input to tc-expr: ~a" form))
+    (let (;; a local version of ret that does the checking
+          [ret 
+           (lambda args
+             (define te (apply ret args))
+             (check-below te expected)
+             (ret expected))])
+      (kernel-syntax-case* form #f 
+        (letrec-syntaxes+values find-method/who) ;; letrec-syntaxes+values is not in kernel-syntax-case literals
+        [stx
+         (syntax-property form 'typechecker:with-handlers)
+         (check-subforms/with-handlers/check form expected)]
+        [stx 
+         (syntax-property form 'typechecker:ignore-some)
+         (let ([ty (check-subforms/ignore form)])
+           (unless ty
+             (tc-error "internal error: ignore-some"))
+           (check-below ty expected))]
+        ;; data
+        [(quote #f) (ret (-val #f) (list (make-False-Effect)) (list (make-False-Effect)))]
+        [(quote #t) (ret (-val #t) (list (make-True-Effect)) (list (make-True-Effect)))]
+        [(quote val)  (ret (tc-literal #'val))]
+        ;; syntax
+        [(quote-syntax datum) (ret Any-Syntax)]
+        ;; mutation!
+        [(set! id val)
+         (match-let* ([(tc-result: id-t) (tc-id #'id)]
+                      [(tc-result: val-t) (tc-expr #'val)])
+           (unless (subtype val-t id-t)
+             (tc-error "Mutation only allowed with compatible types:~n~a is not a subtype of ~a" val-t id-t))
+           (ret -Void))]
+        ;; top-level variable reference - occurs at top level
+        [(#%top . id) (check-below (tc-id #'id) expected)]
+        ;; weird
+        [(#%variable-reference . _)
+         (tc-error "#%variable-reference is not supported by Typed Scheme")]
+        ;; identifiers
+        [x (identifier? #'x) (check-below (tc-id #'x) expected)]
+        ;; w-c-m
+        [(with-continuation-mark e1 e2 e3)
+         (begin (tc-expr/check #'e1 Univ)
+                (tc-expr/check #'e2 Univ)
+                (tc-expr/check #'e3 expected))]  
+        ;; application        
+        [(#%plain-app . _) (tc/app/check form expected)]
+        ;; #%expression
+        [(#%expression e) (tc-expr/check #'e expected)]
+        ;; syntax
+        ;; for now, we ignore the rhs of macros
+        [(letrec-syntaxes+values stxs vals . body)
+         (tc-expr/check (syntax/loc form (letrec-values vals . body)) expected)]
+        ;; begin
+        [(begin e . es) (tc-exprs/check (syntax->list #'(e . es)) expected)]
+        [(begin0 e . es)
+         (begin (tc-exprs/check (syntax->list #'es) Univ)
+                (tc-expr/check #'e expected))]          
+        ;; if
+        [(if tst body) (tc/if-onearm/check #'tst #'body expected)]
+        [(if tst thn els) (tc/if-twoarm/check #'tst #'thn #'els expected)]
+        ;; lambda
+        [(#%plain-lambda formals . body)
+         (tc/lambda/check form #'(formals) #'(body) expected)]        
+        [(case-lambda [formals . body] ...)
+         (tc/lambda/check form #'(formals ...) #'(body ...) expected)] 
+        ;; send
+        [(let-values (((_) meth))
+           (let-values (((_ _) (#%plain-app find-method/who _ rcvr _)))
+             (#%plain-app _ _ args ...)))
+         (tc/send #'rcvr #'meth #'(args ...) expected)]
+        ;; let
+        [(let-values ([(name ...) expr] ...) . body)
+         (tc/let-values/check #'((name ...) ...) #'(expr ...) #'body form expected)]
+        [(letrec-values ([(name ...) expr] ...) . body)
+         (tc/letrec-values/check #'((name ...) ...) #'(expr ...) #'body form expected)]
+        ;; other
+        [_ (tc-error "cannot typecheck unknown form : ~a~n" (syntax->datum form))]
+        ))))
+
+;; type check form in the current type environment
+;; if there is a type error in form, or if it has the wrong annotation, error
+;; otherwise, produce the type of form
+;; syntax[expr] -> type
+(define (tc-expr form)
+  ;; do the actual typechecking of form
+  ;; internal-tc-expr : syntax -> Type    
+  (define (internal-tc-expr form)
+    (kernel-syntax-case* form #f 
+      (letrec-syntaxes+values #%datum #%app lambda find-method/who) ;; letrec-syntaxes+values is not in kernel-syntax-case literals
+      ;; 
+      [stx
+       (syntax-property form 'typechecker:with-handlers)
+       (let ([ty (check-subforms/with-handlers form)])
+         (unless ty
+           (tc-error "internal error: with-handlers"))
+         ty)]
+      [stx 
+       (syntax-property form 'typechecker:ignore-some)
+       (let ([ty (check-subforms/ignore form)])
+         (unless ty
+           (tc-error "internal error: ignore-some"))
+         ty)]
+      
+      ;; data
+      [(quote #f) (ret (-val #f) (list (make-False-Effect)) (list (make-False-Effect)))]
+      [(quote #t) (ret (-val #t) (list (make-True-Effect)) (list (make-True-Effect)))]
+      
+      [(quote val)  (ret (tc-literal #'val))]
+      ;; syntax
+      [(quote-syntax datum) (ret Any-Syntax)]
+      ;; w-c-m
+      [(with-continuation-mark e1 e2 e3)
+       (begin (tc-expr/check #'e1 Univ)
+              (tc-expr/check #'e2 Univ)
+              (tc-expr #'e3))]
+      ;; lambda
+      [(#%plain-lambda formals . body)
+       (tc/lambda form #'(formals) #'(body))]        
+      [(case-lambda [formals . body] ...)
+       (tc/lambda form #'(formals ...) #'(body ...))]  
+      ;; send
+      [(let-values (((_) meth))
+         (let-values (((_ _) (#%plain-app find-method/who _ rcvr _)))
+           (#%plain-app _ _ args ...)))
+       (tc/send #'rcvr #'meth #'(args ...))]
+      ;; let
+      [(let-values ([(name ...) expr] ...) . body)
+       (tc/let-values #'((name ...) ...) #'(expr ...) #'body form)]
+      [(letrec-values ([(name ...) expr] ...) . body)
+       (tc/letrec-values #'((name ...) ...) #'(expr ...) #'body form)]        
+      ;; mutation!
+      [(set! id val)
+       (match-let* ([(tc-result: id-t) (tc-id #'id)]
+                    [(tc-result: val-t) (tc-expr #'val)])
+         (unless (subtype val-t id-t)
+           (tc-error "Mutation only allowed with compatible types:~n~a is not a subtype of ~a" val-t id-t))
+         (ret -Void))]        
+      ;; top-level variable reference - occurs at top level
+      [(#%top . id) (tc-id #'id)]
+      ;; #%expression
+      [(#%expression e) (tc-expr #'e)]
+      ;; weird
+      [(#%variable-reference . _)
+       (tc-error "do not use #%variable-reference")]
+      ;; identifiers
+      [x (identifier? #'x) (tc-id #'x)]                 
+      ;; application        
+      [(#%plain-app . _) (tc/app form)]
+      ;; if
+      [(if tst body) (tc/if-twoarm #'tst #'body #'(#%app void))]
+      [(if tst thn els) (tc/if-twoarm #'tst #'thn #'els)]                          
+
+      
+      
+      ;; syntax
+      ;; for now, we ignore the rhs of macros
+      [(letrec-syntaxes+values stxs vals . body)
+       (tc-expr (syntax/loc form (letrec-values vals . body)))]
+      
+      ;; begin
+      [(begin e . es) (tc-exprs (syntax->list #'(e . es)))]
+      [(begin0 e . es)
+       (begin (tc-exprs (syntax->list #'es))
+              (tc-expr #'e))]
+      ;; other
+      [_ (tc-error "cannot typecheck unknown form : ~a~n" (syntax->datum form))]))
+  
+  (parameterize ([current-orig-stx form])
+    ;(printf "form: ~a~n" (syntax->datum form))
+    ;; the argument must be syntax
+    (unless (syntax? form) 
+      (int-err "bad form input to tc-expr: ~a" form))
+    ;; typecheck form
+    (cond [(type-annotation form) => (lambda (ann) 
+                                       ;(printf "annotated~n")
+                                       (tc-expr/check form ann))]
+          [else (internal-tc-expr form)])))
+
+(define (tc/send rcvr method args [expected #f])
+  (match (tc-expr rcvr)
+    [(tc-result: (Instance: (and c (Class: _ _ methods))))
+     (match (tc-expr method)
+       [(tc-result: (Value: (? symbol? s)))
+        (let* ([ftype (cond [(assq s methods) => cadr]
+                           [else (tc-error "send: method ~a not understood by class ~a" s c)])]
+               [ret-ty (tc/funapp rcvr args (ret ftype) (map tc-expr (syntax->list args)))])
+          (if expected
+              (begin (check-below ret-ty expected) (ret expected))
+              ret-ty))]
+       [(tc-result: t) (int-err "non-symbol methods not yet supported: ~a" t)])]
+    [(tc-result: t) (tc-error "send: expected a class instance, got ~a" t)]))
+
+;; type-check a list of exprs, producing the type of the last one.
+;; if the list is empty, the type is Void.
+;; list[syntax[expr]] -> tc-result
+(define (tc-exprs exprs)
+  (cond [(null? exprs) (ret -Void)]
+        [(null? (cdr exprs)) (tc-expr (car exprs))]
+        [else (tc-expr/check (car exprs) Univ)
+              (tc-exprs (cdr exprs))]))
+
+(define (tc-exprs/check exprs expected)
+  (cond [(null? exprs) (check-below (ret -Void) expected)]
+        [(null? (cdr exprs)) (tc-expr/check (car exprs) expected)]
+        [else (tc-expr/check (car exprs) Univ)
+              (tc-exprs/check (cdr exprs) expected)]))
\ No newline at end of file
diff --git a/collects/typed-scheme/private/tc-if-unit.ss b/collects/typed-scheme/private/tc-if-unit.ss
new file mode 100644
index 0000000000..cf9064803a
--- /dev/null
+++ b/collects/typed-scheme/private/tc-if-unit.ss
@@ -0,0 +1,225 @@
+#lang scheme/unit
+
+(require "planet-requires.ss"
+         "signatures.ss"
+         "type-rep.ss" ;; doesn't need tests
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "lexical-env.ss" ;; maybe needs tests
+         "effect-rep.ss"
+         "mutated-vars.ss"
+         "subtype.ss"
+         (only-in "remove-intersect.ss" 
+                  [remove *remove]
+                  restrict)
+         "union.ss"
+         "type-utils.ss"
+         "tc-utils.ss"
+         "type-comparison.ss"
+         syntax/kerncase
+         mzlib/trace
+         mzlib/plt-match)
+
+;; necessary for creating (#%app void) in tc-if/onearm
+(require (for-template scheme/base))
+
+;; if typechecking   
+(import tc-expr^)
+(export tc-if^)
+
+
+
+;; combinators for typechecking in the context of effects
+;; t/f tells us whether this is the true or the false branch of an if
+;;      neccessary for handling true/false effects
+;; Boolean Expr listof[Effect] option[type] -> TC-Result
+(define (tc-expr/eff t/f expr effs expected)
+  #;(printf "tc-expr/eff : ~a~n" (syntax-object->datum expr))
+  ;; this flag represents whether the refinement proves that this expression cannot be executed
+  (let ([flag (box #f)])
+    ;; this does the operation on the old type
+    ;; type-op : (Type Type -> Type) Type -> _ Type -> Type
+    (define ((type-op f t) _ old)
+      (let ([new-t (f old t)])
+        ;(printf "new-t ~a~n" new-t)
+        ;; if this operation produces an uninhabitable type, then this expression can't be executed
+        (when (type-equal? new-t (Un))
+          ;(printf "setting flag!~n")
+          (set-box! flag #t))
+        ;; have to return something here, so that we can continue typechecking
+        new-t))
+    ;; loop : listof[effect] -> tc-result
+    (let loop ([effs effs])
+      ;; convenience macro for checking the rest of the list
+      (define-syntax check-rest
+        (syntax-rules ()
+          [(check-rest f v)
+           (with-update-type/lexical f v (loop (cdr effs)))]
+          [(check-rest f t v) (check-rest (type-op f t) v)]))
+      (if (null? effs)
+          ;; base case
+          (let* ([reachable? (not (unbox flag))])
+            (cond
+              ;; if flag is true, then we don't want to verify that this branch has the appropriate type
+              ;; in particular, it might be (void)
+              [(and expected reachable?)
+               (tc-expr/check expr expected)]
+              ;; this code is reachable, but we have no expected type
+              [reachable?
+               (tc-expr expr)]
+              ;; otherwise, this code is unreachable
+              ;; and the resulting type should be the empty type
+              [(check-unreachable-code?)
+               (tc-expr/check expr Univ)
+               (ret (Un))]
+              [else
+               (ret (Un))]))
+          ;; recursive case
+          (match (car effs)
+            ;; these effects have no consequence for the typechecking
+            [(True-Effect:)
+             (or t/f (set-box! flag #t)) 
+             (loop (cdr effs))]
+            [(False-Effect:) 
+             (and t/f (set-box! flag #t))
+             (loop (cdr effs))]
+            ;; restrict v to have a type that's a subtype of t
+            [(Restrict-Effect: t v) 
+             (check-rest restrict t v)]
+            ;; remove t from the type of v
+            [(Remove-Effect: t v) (check-rest *remove t v)]
+            ;; just replace the type of v with (-val #f)
+            [(Var-False-Effect: v) (check-rest (lambda (_ old) (-val #f)) v)]
+            ;; v cannot have type (-val #f)
+            [(Var-True-Effect: v) (check-rest *remove (-val #f) v)])))))
+
+;; create a dummy else branch for typechecking
+(define (tc/if-onearm tst body) (tc/if-twoarm tst body (syntax/loc body (#%app void))))
+
+(define (tc/if-onearm/check tst body expected)
+  #;(unless (subtype -Void expected)
+      (tc-error "Single-armed if may return void, but void is not allowed in this context"))
+  (tc/if-twoarm/check tst body (syntax/loc body (#%app void)) expected))
+
+;; the main function
+(define (tc/if-twoarm tst thn els)
+  #;(printf "tc-if/twoarm~n")
+  ;; check in the context of the effects, and return
+  (match-let* ([(tc-result: tst-ty tst-thn-eff tst-els-eff) (tc-expr tst)]
+               [(tc-result: thn-ty thn-thn-eff thn-els-eff) (tc-expr/eff #t thn tst-thn-eff #f)]
+               #;[_ (printf "v is ~a~n" v)]
+               #;[c (current-milliseconds)]
+               [(tc-result: els-ty els-thn-eff els-els-eff) (tc-expr/eff #f els tst-els-eff #f)])
+    #;(printf "v now is ~a~n" (ret els-ty els-thn-eff els-els-eff))
+    #;
+    (printf "els-ty ~a ~a~n" 
+            els-ty c)
+    (match (list thn-thn-eff thn-els-eff els-thn-eff els-els-eff) 
+      ;; this is the case for `or'
+      ;; the then branch has to be #t
+      ;; the else branch has to be a simple predicate
+      ;; FIXME - can something simpler be done by using demorgan's law?
+      ;; note that demorgan's law doesn't hold for scheme `and' and `or' because they can produce arbitrary values
+      ;; FIXME - mzscheme's or macro doesn't match this!
+      [(list (list (True-Effect:)) (list (True-Effect:)) (list (Restrict-Effect: t v)) (list (Remove-Effect: t v*)))
+       (=> unmatch)
+       #;(printf "or branch~n")
+       (match (list tst-thn-eff tst-els-eff)
+         ;; check that the test was also a simple predicate
+         [(list (list (Restrict-Effect: s u)) (list (Remove-Effect: s u*)))
+          (if (and 
+               ;; check that all the predicates are for the for the same identifier
+               (free-identifier=? u u*)
+               (free-identifier=? v v*)
+               (free-identifier=? v u))
+              ;; this is just a very simple or
+              (ret (Un (-val #t) els-ty)
+                   ;; the then and else effects are just the union of the two types
+                   (list (make-Restrict-Effect (Un s t) v))
+                   (list (make-Remove-Effect (Un s t) v)))
+              ;; otherwise, something complicated is happening and we bail
+              (unmatch))]
+         ;; similarly, bail here
+         [_ (unmatch)])]
+      ;; this is the case for `and'
+      [(list _ _ (list (False-Effect:)) (list (False-Effect:)))
+       #;(printf "and branch~n")
+       (ret (Un (-val #f) thn-ty) 
+            ;; we change variable effects to type effects in the test, 
+            ;; because only the boolean result of the test is used
+            ;; whereas, the actual value of the then branch is returned, not just the boolean result
+            (append (map var->type-eff tst-thn-eff) thn-thn-eff)
+            ;; no else effects for and, because any branch could have been false
+            (list))]
+      ;; otherwise this expression has no effects
+      [_ 
+       #;(printf "if base case:~a ~n" (syntax-object->datum tst))
+       #;(printf "els-ty ~a ~a~n" 
+                 els-ty c)
+       #;(printf "----------------------~nels-ty ~a ~nUn~a~n ~a~n" 
+                 els-ty (Un thn-ty els-ty) c)
+       (ret (Un thn-ty els-ty))])))
+
+;; checking version
+(define (tc/if-twoarm/check tst thn els expected)
+  ;; check in the context of the effects, and return
+  (match-let* ([(tc-result: tst-ty tst-thn-eff tst-els-eff) (tc-expr tst)]
+               #;[_ (printf "got to here 0~n")]
+               [(tc-result: thn-ty thn-thn-eff thn-els-eff) (tc-expr/eff #t thn tst-thn-eff expected)]
+               #;[_ (printf "v is ~a~n" v)]
+               #;[c (current-milliseconds)]
+               #;[_ (printf "got to here 1~n")]
+               [(tc-result: els-ty els-thn-eff els-els-eff) (tc-expr/eff #f els tst-els-eff expected)]
+               #;[_ (printf "got to here 2~n")])
+    #;(printf "check: v now is ~a~n" (ret els-ty els-thn-eff els-els-eff))
+    #;(printf "els-ty ~a ~a~n" 
+              els-ty c)
+    (match (list thn-thn-eff thn-els-eff els-thn-eff els-els-eff) 
+      ;; this is the case for `or'
+      ;; the then branch has to be #t
+      ;; the else branch has to be a simple predicate
+      ;; FIXME - can something simpler be done by using demorgan's law?
+      ;; note that demorgan's law doesn't hold for scheme `and' and `or' because they can produce arbitrary values
+      ;; FIXME - mzscheme's or macro doesn't match this!
+      [(list (list (True-Effect:)) (list (True-Effect:)) (list (Restrict-Effect: t v)) (list (Remove-Effect: t v*)))
+       (=> unmatch)
+       ;(printf "or branch~n")
+       (match (list tst-thn-eff tst-els-eff)
+         ;; check that the test was also a simple predicate
+         [(list (list (Restrict-Effect: s u)) (list (Remove-Effect: s u*)))
+          (if (and 
+               ;; check that all the predicates are for the for the same identifier
+               (free-identifier=? u u*)
+               (free-identifier=? v v*)
+               (free-identifier=? v u))
+              ;; this is just a very simple or
+              (let ([t (Un (-val #t) els-ty)])
+                (check-below t expected)
+                (ret t
+                     ;; the then and else effects are just the union of the two types
+                     (list (make-Restrict-Effect (Un s t) v))
+                     (list (make-Remove-Effect (Un s t) v))))
+              ;; otherwise, something complicated is happening and we bail
+              (unmatch))]
+         ;; similarly, bail here
+         [_ (unmatch)])]
+      ;; this is the case for `and'
+      [(list _ _ (list (False-Effect:)) (list (False-Effect:)))
+       ;(printf "and branch~n")
+       (let ([t (Un thn-ty (-val #f))])
+         (check-below t expected)              
+         (ret t 
+              ;; we change variable effects to type effects in the test, 
+              ;; because only the boolean result of the test is used
+              ;; whereas, the actual value of the then branch is returned, not just the boolean result
+              (append (map var->type-eff tst-thn-eff) thn-thn-eff)
+              ;; no else effects for and, because any branch could have been false
+              (list)))]
+      ;; otherwise this expression has no effects
+      [_ 
+       (let ([t (Un thn-ty els-ty)])
+         (check-below t expected)
+         (ret t))])))
+
+
+
+;)
\ No newline at end of file
diff --git a/collects/typed-scheme/private/tc-lambda-unit.ss b/collects/typed-scheme/private/tc-lambda-unit.ss
new file mode 100644
index 0000000000..deeb33b997
--- /dev/null
+++ b/collects/typed-scheme/private/tc-lambda-unit.ss
@@ -0,0 +1,196 @@
+#lang scheme/unit
+
+(require "signatures.ss"
+         (lib "trace.ss")
+         (except-in "type-rep.ss" make-arr) ;; doesn't need tests
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "type-environments.ss" ;; doesn't need tests
+         "lexical-env.ss" ;; maybe needs tests
+         "type-annotation.ss" ;; has tests
+         "utils.ss"
+         "type-utils.ss"
+         "effect-rep.ss"
+         "tc-utils.ss"
+         "resolve-type.ss"
+         (lib "plt-match.ss")
+         (only-in "type-effect-convenience.ss" [make-arr* make-arr]))
+(require (for-template mzscheme "internal-forms.ss"))
+
+(import tc-expr^)
+(export tc-lambda^)
+
+(define (remove-var id thns elss)
+  (let/ec exit
+    (define (fail) (exit #f))
+    (define (rv e)
+      (match e
+        [(Var-True-Effect: v) (if (free-identifier=? v id) (make-Latent-Var-True-Effect) (fail))]
+        [(Var-False-Effect: v) (if (free-identifier=? v id) (make-Latent-Var-False-Effect) (fail))]
+        [(or (True-Effect:) (False-Effect:)) e]
+        [(Restrict-Effect: t v) (if (free-identifier=? v id) (make-Latent-Restrict-Effect t) (fail))]
+        [(Remove-Effect: t v) (if (free-identifier=? v id) (make-Latent-Remove-Effect t) (fail))]))
+    (cons (map rv thns) (map rv elss))))
+
+
+;; typecheck a single lambda, with argument list and body
+;; fixme: abstract the two cases!
+;; syntax-list[id] block listof[type] type option[type] -> arr
+(define (tc/lambda-clause/check args body arg-tys ret-ty rest-ty)
+  (syntax-case args ()
+    [(args* ...)    
+     (if (ormap (lambda (e) (not (type-annotation e))) (syntax->list #'(args* ...)))
+         (let* ([arg-list (syntax->list #'(args* ...))])
+           (unless (= (length arg-list) (length arg-tys))
+             (tc-error "Expected function with ~a arguments, but got function with ~a arguments" (length arg-tys) (length arg-list)))
+           (for-each (lambda (a) (printf/log "Lambda Var: ~a~n" (syntax-e a))) arg-list)
+           (with-lexical-env/extend 
+            arg-list arg-tys
+            (match (tc-exprs/check (syntax->list body) ret-ty)
+              [(tc-result: t thn els)
+               (cond
+                 ;; this is T-AbsPred                
+                 ;; if this function takes only one argument, and all the effects are about that one argument
+                 [(and (= 1 (length arg-list)) (remove-var (car arg-list) thn els))
+                  => (lambda (thn/els) (make-arr arg-tys t #f (car thn/els) (cdr thn/els)))]
+                 ;; otherwise, the simple case
+                 [else (make-arr arg-tys t)])]
+              [t (int-err "bad match - not a tc-result: ~a" t)])))
+         (let* ([arg-list (syntax->list #'(args* ...))]
+                [arg-types (map get-type arg-list)])
+           (for-each (lambda (a) (printf/log "Lambda Var: ~a~n" (syntax-e a))) arg-list)
+           (with-lexical-env/extend 
+            arg-list arg-types
+            (match (tc-exprs/check (syntax->list body) ret-ty)
+              [(tc-result: t thn els)
+               (cond
+                 ;; this is T-AbsPred                
+                 ;; if this function takes only one argument, and all the effects are about that one argument
+                 [(and (= 1 (length arg-list)) (remove-var (car arg-list) thn els))
+                  => (lambda (thn/els) (make-arr arg-types t #f (car thn/els) (cdr thn/els)))]
+                 ;; otherwise, the simple case
+                 [else (make-arr arg-types t)])]
+              [t (int-err "bad match - not a tc-result: ~a" t)]))))]
+    [(args* ... . rest)
+     (let ([t (tc/lambda-clause args body)])               
+       (check-below (make-Function (list t)) (make-Function (list (make-arr arg-tys ret-ty rest-ty))))
+       t)]))
+
+;; syntax-list[id] block -> arr
+(define (tc/lambda-clause args body)
+  (syntax-case args ()
+    [(args ...)       
+     (let* ([arg-list (syntax->list #'(args ...))]
+            [arg-types (map get-type arg-list)])
+       (for-each (lambda (a) (printf/log "Lambda Var: ~a~n" (syntax-e a))) arg-list)
+       (with-lexical-env/extend 
+        arg-list arg-types
+        (match (tc-exprs (syntax->list body))
+          [(tc-result: t thn els)
+           (cond
+             ;; this is T-AbsPred                
+             ;; if this function takes only one argument, and all the effects are about that one argument
+             [(and (= 1 (length arg-list)) (remove-var (car arg-list) thn els))
+              => (lambda (thn/els) (make-arr arg-types t #f (car thn/els) (cdr thn/els)))]
+             ;; otherwise, the simple case
+             [else (make-arr arg-types t)])]
+          [t (int-err "bad match - not a tc-result: ~a" t)])))]
+    [(args ... . rest)
+     (let* ([arg-list (syntax->list #'(args ...))]
+            [arg-types (map get-type arg-list)]
+            [rest-type (get-type #'rest)])
+       (for-each (lambda (a) (printf/log "Lambda Var: ~a~n" (syntax-e a))) (cons #'rest arg-list))
+       (with-lexical-env/extend 
+        (cons #'rest arg-list) 
+        (cons (make-Listof rest-type) arg-types)
+        (match-let ([(tc-result: t thn els) (tc-exprs (syntax->list body))])
+          (make-arr arg-types t rest-type))))]))
+
+;(trace tc-args)
+
+;; tc/mono-lambda : syntax-list syntax-list -> Funty
+;; typecheck a sequence of case-lambda clauses
+(define (tc/mono-lambda formals bodies expected)
+  (define (syntax-len s)
+    (cond [(syntax->list s) => length]
+          [else (let loop ([s s])
+                  (if (pair? (syntax-e s))
+                      (+ 1 (loop (cdr (syntax-e s))))
+                      1))]))
+  (if (and expected
+           (= 1 (length (syntax->list formals))))
+      ;; special case for not-case-lambda
+      (let loop ([expected expected])
+        (match expected          
+          [(Mu: _ _) (loop (unfold expected))]
+          [(Function: (list (arr: args ret rest _ _))) 
+           (tc/lambda-clause/check (car (syntax->list formals)) (car (syntax->list bodies)) args ret rest)]
+          [t (let ([t (tc/mono-lambda formals bodies #f)])
+               (check-below t expected))]))
+      (let loop ([formals (syntax->list formals)] 
+                 [bodies (syntax->list bodies)]
+                 [formals* null]
+                 [bodies* null]
+                 [nums-seen null])
+        (cond 
+          [(null? formals)
+           (make-Function (map tc/lambda-clause (reverse formals*) (reverse bodies*)))]
+          [(memv (syntax-len (car formals)) nums-seen)
+           ;; we check this clause, but it doesn't contribute to the overall type
+           (tc/lambda-clause (car formals) (car bodies))
+           (loop (cdr formals) (cdr bodies) formals* bodies* nums-seen)]
+          [else
+           (loop (cdr formals) (cdr bodies) 
+                 (cons (car formals) formals*)
+                 (cons (car bodies) bodies*)
+                 (cons (syntax-len (car formals)) nums-seen))]))))
+
+(define (tc/lambda form formals bodies)
+  (tc/lambda/internal form formals bodies #f))
+
+;; typecheck a sequence of case-lambda clauses, which is possibly polymorphic
+;; tc/lambda/internal syntax syntax-list syntax-list option[type] -> Type
+(define (tc/lambda/internal form formals bodies expected)
+  (if (or (syntax-property form 'typechecker:plambda) (Poly? expected))
+      (tc/plambda form formals bodies expected)
+      (ret (tc/mono-lambda formals bodies expected))))
+
+(define (tc/lambda/check form formals bodies expected)
+  (tc/lambda/internal form formals bodies expected))
+
+;; tc/plambda syntax syntax-list syntax-list type -> Poly
+;; formals and bodies must by syntax-lists
+(define (tc/plambda form formals bodies expected)
+  (match expected
+    [(Poly-names: ns (and expected* (Function: _)))
+     (with-syntax ()
+       (let* ([tvars (let ([p (syntax-property form 'typechecker:plambda)])
+                       (or (and p (map syntax-e (syntax->list p)))
+                           ns))]
+              [literal-tvars tvars]
+              [new-tvars (map make-F literal-tvars)]
+              [ty (parameterize ([current-tvars (extend-env literal-tvars new-tvars (current-tvars))])
+                    (tc/mono-lambda formals bodies expected*))])
+         ;(printf "plambda: ~a ~a ~a ~n" literal-tvars new-tvars ty)
+         (ret (make-Poly literal-tvars ty))))]
+    [_ (tc-error "Expected a value of type ~a, but got a polymorphic function." expected)]))
+    
+
+;; form : a syntax object for error reporting
+;; formals : the formal arguments to the loop
+;; body : a block containing the body of the loop
+;; name : the name of the loop
+;; args : the types of the actual arguments to the loop
+;; ret : the expected return type of the whole expression
+(define (tc/rec-lambda/check form formals body name args ret)
+  #;(printf "formals: ~a~n" (syntax->datum formals))
+  (with-lexical-env/extend
+   (syntax->list formals) args
+   (let ([t (->* args ret)])
+     (with-lexical-env/extend
+      (list name) (list t)
+      (begin (tc-exprs/check (syntax->list body) ret)
+             (make-Function (list t)))))))
+
+;(trace tc/mono-lambda)
+
+
diff --git a/collects/typed-scheme/private/tc-let-unit.ss b/collects/typed-scheme/private/tc-let-unit.ss
new file mode 100644
index 0000000000..8a137fc785
--- /dev/null
+++ b/collects/typed-scheme/private/tc-let-unit.ss
@@ -0,0 +1,121 @@
+#lang scheme/unit
+
+(require "signatures.ss"
+         "type-effect-convenience.ss"
+         "lexical-env.ss"
+         "type-annotation.ss"
+         "type-alias-env.ss"
+         "type-env.ss"
+         "parse-type.ss"
+         "utils.ss"
+         syntax/free-vars
+         mzlib/trace
+         syntax/kerncase
+         (for-template 
+          scheme/base
+          "internal-forms.ss"))
+
+(require (only-in srfi/1 [member member1]))
+
+
+(import tc-expr^)
+(export tc-let^)
+
+(define (do-check expr->type namess types form exprs body clauses expected)
+  ;; just for error reporting
+  #;(define clauses (syntax-case form () [(lv cl . b) (syntax->list #'cl)]))
+  ;; extend the lexical environment for checking the body
+  (with-lexical-env/extend 
+   ;; the list of lists of name
+   namess
+   ;; the types
+   types
+   (for-each (lambda (stx e t) (check-type stx (expr->type e) t))
+             clauses
+             exprs 
+             (map list->values-ty types))
+   (if expected 
+       (tc-exprs/check (syntax->list body) expected)
+       (tc-exprs (syntax->list body)))))
+
+#|
+;; this is more abstract, but sucks
+  (define ((mk f) namess exprs body form)
+    (let* ([names (map syntax->list (syntax->list namess))]
+           [exprs (syntax->list exprs)])
+      (f (lambda (e->t namess types exprs) (do-check e->t namess types form exprs body)) names exprs)))
+  
+  (define tc/letrec-values 
+    (mk (lambda (do names exprs)
+          (let ([types (map (lambda (l) (map get-type l)) names)])
+            (do tc-expr/t names types exprs)))))
+  
+  (define tc/let-values
+    (mk (lambda (do names exprs)
+          (let* (;; the types of the exprs
+                 [inferred-types (map tc-expr/t exprs)]
+                 ;; the annotated types of the name (possibly using the inferred types)
+                 [types (map get-type/infer names inferred-types)])
+            (do (lambda (x) x) names types inferred-types)))))
+  |#
+
+(define (tc/letrec-values/check namess exprs body form expected)
+  (tc/letrec-values/internal namess exprs body form expected))
+
+(define (tc/letrec-values namess exprs body form)
+  (tc/letrec-values/internal namess exprs body form #f))
+
+(define (tc/letrec-values/internal namess exprs body form expected)
+  (let* ([names (map syntax->list (syntax->list namess))]
+         [flat-names (apply append names)]
+         [exprs (syntax->list exprs)]           
+         ;; the clauses for error reporting
+         [clauses (syntax-case form () [(lv cl . b) (syntax->list #'cl)])])
+    (for-each (lambda (names body)
+                (kernel-syntax-case* body #f (values :-internal define-type-alias-internal)
+                  [(begin (quote-syntax (define-type-alias-internal nm ty)) (#%plain-app values))
+                   (register-resolved-type-alias #'nm (parse-type #'ty))]
+                  [(begin (quote-syntax (:-internal nm ty)) (#%plain-app values))
+                   (register-type/undefined #'nm (parse-type #'ty))]
+                  [_ (void)]))
+              names
+              exprs)
+    (let loop ([names names] [exprs exprs] [flat-names flat-names] [clauses clauses])
+      (cond 
+        ;; after everything, check the body expressions
+        [(null? names) 
+         (if expected (tc-exprs/check (syntax->list body) expected) (tc-exprs (syntax->list body)))]
+        ;; if none of the names bound in the letrec are free vars of this rhs
+        [(not (ormap (lambda (n) (member1 n flat-names bound-identifier=?)) (free-vars (car exprs))))
+         ;; then check this expression separately
+         (let ([t (tc-expr/t (car exprs))])               
+           (with-lexical-env/extend
+            (list (car names))
+            (list (get-type/infer (car names) t))
+            (loop (cdr names) (cdr exprs) (apply append (cdr names)) (cdr clauses))))]
+        [else
+         ;(for-each (lambda (vs) (for-each (lambda (v) (printf/log "Letrec Var: ~a~n" (syntax-e v))) vs)) names)
+         (do-check tc-expr/t names (map (lambda (l) (map get-type l)) names) form exprs body clauses expected)]))))
+
+(define (tc/let-values/internal namess exprs body form expected)
+  (let* (;; a list of each name clause
+         [names (map syntax->list (syntax->list namess))]
+         ;; all the trailing expressions - the ones actually bound to the names
+         [exprs (syntax->list exprs)]
+         ;; the types of the exprs
+         [inferred-types (map tc-expr/t exprs)]
+         ;; the annotated types of the name (possibly using the inferred types)
+         [types (map get-type/infer names inferred-types)]
+         ;; the clauses for error reporting
+         [clauses (syntax-case form () [(lv cl . b) (syntax->list #'cl)])])
+    (do-check (lambda (x) x) names types form inferred-types body clauses expected)))
+
+(define (tc/let-values/check namess exprs body form expected)
+  (tc/let-values/internal namess exprs body form expected))
+
+(define (tc/let-values namess exprs body form)
+  (tc/let-values/internal namess exprs body form #f))
+
+;(trace tc/letrec-values/internal)
+
+
diff --git a/collects/typed-scheme/private/tc-structs.ss b/collects/typed-scheme/private/tc-structs.ss
new file mode 100644
index 0000000000..8237507ddd
--- /dev/null
+++ b/collects/typed-scheme/private/tc-structs.ss
@@ -0,0 +1,252 @@
+#lang scheme/base
+
+(require (lib "struct.ss" "syntax")
+         (lib "etc.ss")
+         "type-rep.ss" ;; doesn't need tests
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "type-env.ss" ;; maybe needs tests
+         "type-utils.ss"
+         "parse-type.ss" ;; has tests
+         "type-environments.ss" ;; doesn't need tests
+         "type-name-env.ss" ;; maybe needs tests
+         "union.ss"
+         "tc-utils.ss"
+         "resolve-type.ss"
+         (lib "kerncase.ss" "syntax")
+         (lib "trace.ss")
+         (lib "kw.ss")
+         (lib "plt-match.ss"))
+
+
+(require (for-template scheme/base
+                       "internal-forms.ss"))
+
+(provide tc/struct tc/poly-struct names-of-struct tc/builtin-struct d-s)
+
+(define (names-of-struct stx)
+  (define (parent? stx)
+    (syntax-case stx ()
+      [(a b)
+       (and (identifier? #'a)
+            (identifier? #'b))
+       #t]
+      [a
+       (identifier? #'a)
+       #t]
+      [_ #f]))
+  (kernel-syntax-case* stx #f 
+    (define-typed-struct-internal values)
+    [(#%define-values () (begin (quote-syntax (define-typed-struct-internal (ids ...) nm/par . rest)) (#%plain-app values)))
+     (and (andmap identifier? (syntax->list #'(ids ...)))
+          (parent? #'nm/par))
+     (let-values ([(nm _1 _2 _3 _4) (parse-parent #'nm/par)])
+       (list nm))]
+    [(#%define-values () (begin (quote-syntax (define-typed-struct-internal nm/par . rest)) (#%plain-app values)))
+     (let-values ([(nm _1 _2 _3 _4) (parse-parent #'nm/par)])
+       (list nm))]
+    [(#%define-values () (begin (quote-syntax (define-typed-struct/exec-internal nm/par . rest)) (#%plain-app values)))
+     (let-values ([(nm _1 _2 _3 _4) (parse-parent #'nm/par)])
+       (list nm))]
+    [_ (int-err "not define-typed-struct: ~a" (syntax->datum stx))]))
+
+;; parse name field of struct, determining whether a parent struct was specified
+;; syntax -> (values identifier Option[Type](must be name) Option[Type](must be struct) List[Types] Symbol Type)
+(define (parse-parent nm/par)
+  (syntax-case nm/par ()
+    [nm (identifier? #'nm) (values #'nm #f #f (syntax-e #'nm) (make-F (syntax-e #'nm)))]
+    [(nm par) (let* ([parent0 (parse-type #'par)]
+                     [parent (resolve-name parent0)])
+                (values #'nm parent0 parent (syntax-e #'nm) (make-F (syntax-e #'nm))))]
+    [_ (int-err "not a parent: ~a" (syntax->datum nm/par))]))
+
+;; generate struct names given type name and field names
+;; generate setters if setters? is true
+;; all have syntax loc of name
+;; identifier listof[identifier] boolean -> (values identifier identifier list[identifier] Option[list[identifier]])
+(define (struct-names nm flds setters?)
+  (define (split l)
+    (let loop ([l l] [getters '()] [setters '()])
+      (if (null? l)
+          (values (reverse getters) (reverse setters))
+          (loop (cddr l) (cons (car l) getters) (cons (cadr l) setters)))))
+  (match (build-struct-names nm flds #f (not setters?) nm)
+    [(list _ maker pred getters/setters ...) 
+     (if setters?
+         (let-values ([(getters setters) (split getters/setters)])
+           (values maker pred getters setters))
+         (values maker pred getters/setters #f))]))
+
+;; gets the fields of the parent type, if they exist
+;; Option[Struct-Ty] -> Listof[Type]
+(define (get-parent-flds p)
+  (match p
+    [(Struct: _ _ flds _) flds]
+    [(Name: n) (get-parent-flds (lookup-type-name n))]
+    [#f null]))
+
+
+;; construct all the various types for structs, and then register the approriate names
+;; identifier listof[identifier] type listof[Type] listof[Type] boolean -> Type listof[Type] listof[Type]
+(define (mk/register-sty nm flds parent parent-field-types types 
+                         #:wrapper [wrapper values] 
+                         #:type-wrapper [type-wrapper values]
+                         #:mutable [setters? #f]
+                         #:proc-ty [proc-ty #f]
+                         #:maker [maker #f])
+  (let* ([name (syntax-e nm)]
+         [fld-types (append parent-field-types types)]
+         [sty (make-Struct name parent fld-types proc-ty)]
+         [external-fld-types/no-parent types]
+         [external-fld-types fld-types])
+    (register-struct-types nm sty flds external-fld-types external-fld-types/no-parent setters? 
+                           #:wrapper wrapper
+                           #:type-wrapper type-wrapper
+                           #:maker maker)))
+
+;; generate names, and register the approriate types give field types and structure type
+;; optionally wrap things
+;; identifier Type Listof[identifer] Listof[Type] Listof[Type] #:wrapper (Type -> Type) #:maker identifier
+(define (register-struct-types nm sty flds external-fld-types external-fld-types/no-parent setters?
+                               #:wrapper [wrapper (lambda (x) x)]
+                               #:type-wrapper [type-wrapper values]
+                               #:maker [maker* #f])
+  ;; create the approriate names that define-struct will bind
+  (define-values (maker pred getters setters) (struct-names nm flds setters?))
+  ;; the type name that is used in all the types
+  (define name (type-wrapper (make-Name nm)))
+  ;; register the type name
+  (register-type-name nm (wrapper sty))
+  ;; register the various function types
+  (register-type (or maker* maker) (wrapper (->* external-fld-types name)))
+  (register-types getters
+                  (map (lambda (t) (wrapper (->* (list name) t))) external-fld-types/no-parent))
+  (when setters?    
+    #;(printf "setters: ~a~n" (syntax-object->datum setters))
+    (register-types setters
+                    (map (lambda (t) (wrapper (->* (list name t) -Void))) external-fld-types/no-parent)))
+  (register-type pred (make-pred-ty (wrapper name))))
+
+;; check and register types for a polymorphic define struct
+;; tc/poly-struct : Listof[identifier] (U identifier (list identifier identifier)) Listof[identifier] Listof[syntax] -> void
+(define (tc/poly-struct vars nm/par flds tys)
+  ;; parent field types can't actually be determined here
+  (define-values (nm parent-name parent name name-tvar) (parse-parent nm/par))
+  ;; create type variables for the new type parameters
+  (define tvars (map syntax-e vars))
+  (define new-tvars (map make-F tvars))
+  ;; parse the types
+  (define types
+    ;; add the type parameters of this structure to the tvar env
+    (parameterize ([current-tvars (extend-env tvars new-tvars (current-tvars))])
+      ;; parse the field types
+      (map parse-type tys)))
+  ;; instantiate the parent if necessary, with new-tvars
+  (define concrete-parent 
+    (if (Poly? parent)
+        (instantiate-poly parent new-tvars)
+        parent))
+  ;; get the fields of the parent, if it exists
+  (define parent-field-types (get-parent-flds concrete-parent))
+  ;; create the actual structure type, and the types of the fields
+  ;; that the outside world will see
+  ;; then register them
+  (mk/register-sty nm flds parent-name parent-field-types types
+                   ;; wrap everything in the approriate forall
+                   #:wrapper (lambda (t) (make-Poly tvars t))
+                   #:type-wrapper (lambda (t) (make-App t new-tvars #f))))
+
+
+;; typecheck a non-polymophic struct and register the approriate types
+;; tc/struct : (U identifier (list identifier identifier)) Listof[identifier] Listof[syntax] -> void
+(define (tc/struct nm/par flds tys [proc-ty #f] #:maker [maker #f])
+  ;; get the parent info and create some types and type variables
+  (define-values (nm parent-name parent name name-tvar) (parse-parent nm/par))
+  ;; parse the field types, and determine if the type is recursive
+  (define types (map parse-type tys))
+  (define proc-ty-parsed  
+    (if proc-ty
+        (parse-type proc-ty)
+        #f))
+  ;; create the actual structure type, and the types of the fields
+  ;; that the outside world will see
+  (mk/register-sty nm flds parent-name (get-parent-flds parent) types
+                   ;; procedure
+                   #:proc-ty proc-ty-parsed
+                   #:maker maker))
+
+;; register a struct type
+;; convenience function for built-in structs
+;; tc/builtin-struct : identifier identifier Listof[identifier] Listof[Type] Listof[Type] -> void
+(define (tc/builtin-struct nm parent flds tys parent-tys)
+  (let ([parent* (if parent (make-Name parent) #f)])
+    (mk/register-sty nm flds parent* parent-tys tys #:mutable #t)))
+
+;; syntax for tc/builtin-struct
+(define-syntax d-s 
+  (syntax-rules (:) 
+    [(_ (nm par) ([fld : ty] ...) (par-ty ...))
+     (tc/builtin-struct #'nm #'par
+                        (list #'fld ...)
+                        (list ty ...)
+                        (list par-ty ...))]
+    [(_ nm ([fld : ty] ...) (par-ty ...))
+     (tc/builtin-struct #'nm #f
+                        (list #'fld ...)
+                        (list ty ...)
+                        (list par-ty ...))]))
+
+;; This is going away!
+#|
+
+;; parent-nm is an identifier with the name of the defined type
+;; variants is (list id id (list (cons id unparsed-type))) - first id is name of variant, second is name of maker, 
+;;     list is name of field w/ type
+;; top-pred is an identifier
+;; produces void
+(define (tc/define-type parent-nm top-pred variants)
+  ;; the symbol and type variable used for parsing
+  (define parent-sym (syntax-e parent-nm))
+  (define parent-tvar (make-F parent-sym))
+  
+  ;; create the initial struct type, which contains type variables
+  (define (mk-initial-variant nm fld-tys-stx)
+    ;; parse the types (recursiveness doesn't matter)
+    (define-values (fld-tys _) (FIXME parent-sym parent-tvar fld-tys-stx))     
+    (make-Struct (syntax-e nm) #f fld-tys #f))
+  
+  ;; create the union type that is the total type
+  (define (mk-un-ty parent-sym variant-struct-tys)
+    (make-Mu parent-sym (apply Un variant-struct-tys)))     
+  
+  ;; generate the names and call mk-variant
+  (define (mk-variant nm maker-name fld-names un-ty variant-struct-ty parent-nm)
+    ;; construct the actual type of this variant
+    (define variant-ty (subst parent-nm un-ty variant-struct-ty))
+    ;; the fields of this variant
+    (match-define (Struct: _ _ fld-types _) variant-ty)
+    ;; register all the types (with custon maker name)
+    (register-struct-types nm variant-ty fld-names fld-types fld-types #f #:maker maker-name))
+  
+  ;; all the names
+  (define variant-names (map car variants))
+  (define variant-makers (map cadr variants))
+  (define variant-flds (map caddr variants))    
+  ;; create the initial variants, which don't have the parent substituted in
+  (define variant-struct-tys (map (lambda (n flds) (mk-initial-variant n (map car flds))) variant-names variant-flds))
+  ;; just the names of each variant's fields
+  (define variant-fld-names (map (lambda (x) (map cdr x)) variant-flds))
+  
+  ;; the type of the parent
+  (define un-ty (mk-un-ty parent-sym variant-struct-tys))
+  
+  ;; register the types for the parent
+  (register-type top-pred (make-pred-ty un-ty))
+  (register-type-name parent-nm un-ty)
+  
+  ;; construct all the variants, and register the appropriate names
+  (for-each (lambda (nm mk fld-names sty) (mk-variant nm mk fld-names un-ty sty parent-sym))
+            variant-names variant-makers variant-fld-names variant-struct-tys))
+
+
+
+|#
\ No newline at end of file
diff --git a/collects/typed-scheme/private/tc-toplevel.ss b/collects/typed-scheme/private/tc-toplevel.ss
new file mode 100644
index 0000000000..496df7905b
--- /dev/null
+++ b/collects/typed-scheme/private/tc-toplevel.ss
@@ -0,0 +1,245 @@
+#lang scheme/unit
+
+
+(require syntax/kerncase
+         mzlib/etc
+         mzlib/plt-match
+         "signatures.ss"
+         "tc-structs.ss"
+         "type-utils.ss"
+         "utils.ss" ;; doesn't need tests
+         "type-effect-convenience.ss" ;; maybe needs tests
+         "internal-forms.ss" ;; doesn't need tests
+         "type-env.ss" ;; maybe needs tests
+         "parse-type.ss" ;; has tests
+         "tc-utils.ss" ;; doesn't need tests
+         "type-annotation.ss" ;; has tests
+         "type-name-env.ss" ;; maybe needs tests
+         "init-envs.ss"
+         "mutated-vars.ss"
+         "def-binding.ss"
+         "provide-handling.ss"
+         "type-alias-env.ss"
+         "type-contract.ss"
+         (only-in "prims.ss" :)
+         (for-template
+          (only-in "prims.ss" :)
+          "internal-forms.ss"
+          "tc-utils.ss"
+          (lib "contract.ss")
+          scheme/base))
+
+(import tc-expr^ check-subforms^)
+(export typechecker^)
+
+(define (tc-toplevel/pass1 form)
+  ;(printf "form-top: ~a~n" form)
+  ;; first, find the mutated variables:
+  (find-mutated-vars form)
+  (parameterize ([current-orig-stx form])
+    (kernel-syntax-case* form #f (define-type-alias-internal define-typed-struct-internal define-type-internal 
+                                   define-typed-struct/exec-internal :-internal assert-predicate-internal
+                                   require/typed-internal values :)
+      ;; forms that are handled in other ways
+      [stx 
+       (or (syntax-property form 'typechecker:ignore) 
+           (syntax-property form 'typechecker:ignore-some))
+       (list)]
+      
+      ;; type aliases have already been handled by an earlier pass
+      [(define-values () (begin (quote-syntax (define-type-alias-internal nm ty)) (#%plain-app values)))
+       (list)]
+      
+      ;; require/typed
+      [(define-values () (begin (quote-syntax (require/typed-internal nm ty)) (#%plain-app values)))
+       (register-type #'nm (parse-type #'ty))]
+      
+      ;; define-typed-struct
+      [(define-values () (begin (quote-syntax (define-typed-struct-internal nm ([fld : ty] ...))) (#%plain-app values)))
+       (tc/struct #'nm (syntax->list #'(fld ...)) (syntax->list #'(ty ...)))]
+      [(define-values () (begin (quote-syntax (define-typed-struct-internal nm ([fld : ty] ...) #:maker m)) (#%plain-app values)))
+       (tc/struct #'nm (syntax->list #'(fld ...)) (syntax->list #'(ty ...)) #:maker #'m)]
+      ;; define-typed-struct w/ polymorphism
+      [(define-values () (begin (quote-syntax (define-typed-struct-internal (vars ...) nm ([fld : ty] ...))) (#%plain-app values)))
+       (tc/poly-struct (syntax->list #'(vars ...)) #'nm (syntax->list #'(fld ...)) (syntax->list #'(ty ...)))]    
+      
+      ;; executable structs - this is a big hack
+      [(define-values () (begin (quote-syntax (define-typed-struct/exec-internal nm ([fld : ty] ...) proc-ty)) (#%plain-app values)))
+       (tc/struct #'nm (syntax->list #'(fld ...)) (syntax->list #'(ty ...)) #'proc-ty)]
+      
+      ;; predicate assertion - needed for define-type b/c or doesn't work
+      [(define-values () (begin (quote-syntax (assert-predicate-internal ty pred)) (#%plain-app values)))
+       (register-type #'pred (make-pred-ty (parse-type #'ty)))]
+      
+      ;; top-level type annotation
+      [(define-values () (begin (quote-syntax (:-internal id ty)) (#%plain-app values)))
+       (identifier? #'id)
+       (register-type/undefined #'id (parse-type #'ty))]
+      
+      ;; values definitions
+      [(define-values (var ...) expr)
+       (let* ([vars (syntax->list #'(var ...))])
+         (cond
+           ;; if all the variables have types, we stick them into the environment
+           [(andmap (lambda (s) (syntax-property s 'type-label)) vars)        
+            (let ([ts (map get-type vars)])
+              (for-each register-type vars ts)
+              (map make-def-binding ts vars))]
+           ;; if this already had an annotation, we just construct the binding reps
+           [(andmap (lambda (s) (lookup-type s (lambda () #f))) vars)
+            (for-each finish-register-type vars)
+            (map (lambda (s) (make-def-binding s (lookup-type s))) vars)]
+           ;; special case to infer types for top level defines - should handle the multiple values case here
+           [(and (= 1 (length vars)) 
+                 (with-handlers ([exn:fail? (lambda _ #f)]) (tc-expr #'expr)))
+            => (match-lambda 
+                 [(tc-result: t)
+                  (register-type (car vars) t)
+                  (list (car vars) t)])]
+           [else
+            (tc-error "Untyped definition : ~a" (map syntax-e vars))]))]
+      
+      ;; to handle the top-level, we have to recur into begins
+      [(begin . rest)
+       (apply append (filter list? (map tc-toplevel/pass1 (syntax->list #'rest))))]
+      
+      ;; define-syntaxes just get noted
+      [(define-syntaxes (var ...) . rest)
+       (andmap identifier? (syntax->list #'(var ...)))
+       (map make-def-stx-binding (syntax->list #'(var ...)))]
+      
+      ;; otherwise, do nothing in this pass
+      ;; handles expressions, provides, requires, etc and whatnot
+      [_ (list)])))
+
+
+
+
+
+;; typecheck the expressions of a module-top-level form
+;; no side-effects
+;; syntax -> void
+(define (tc-toplevel/pass2 form)
+  (parameterize ([current-orig-stx form])
+    (kernel-syntax-case* form #f (define-type-alias-internal define-typed-struct-internal define-type-internal 
+                                   require/typed-internal values)
+      ;; these forms we have been instructed to ignore
+      [stx 
+       (syntax-property form 'typechecker:ignore)
+       (void)]
+      
+      ;; this is a form that we mostly ignore, but we check some interior parts
+      [stx 
+       (syntax-property form 'typechecker:ignore-some)
+       (check-subforms/ignore form)]
+      
+      ;; these forms should always be ignored
+      [(#%require . _) (void)]
+      [(#%provide . _) (void)]
+      [(define-syntaxes . _) (void)]
+      [(define-values-for-syntax . _) (void)]
+      
+      ;; these forms are handled in pass1
+      [(define-values () (begin (quote-syntax (require/typed-internal . rest)) (#%plain-app values)))
+       (void)]
+      [(define-values () (begin (quote-syntax (define-type-alias-internal . rest)) (#%plain-app values)))
+       (void)]
+      [(define-values () (begin (quote-syntax (define-typed-struct-internal . rest)) (#%plain-app values)))
+       (void)]          
+      
+      ;; definitions just need to typecheck their bodies
+      [(define-values (var ...) expr)
+       (let* ([vars (syntax->list #'(var ...))]
+              [ts (map lookup-type vars)])
+         (tc-expr/check #'expr (list->values-ty ts)))
+       (void)]
+      
+      ;; to handle the top-level, we have to recur into begins
+      [(begin) (void)]
+      [(begin . rest)
+       (let loop ([l (syntax->list #'rest)])
+         (if (null? (cdr l))
+             (tc-toplevel/pass2 (car l))
+             (begin (tc-toplevel/pass2 (car l))
+                    (loop (cdr l)))))]
+      
+      ;; otherwise, the form was just an expression
+      [_ (tc-expr form)])))
+
+
+
+;; new implementation of type-check
+(define-syntax-rule (internal-syntax-pred nm)
+  (lambda (form)
+    (kernel-syntax-case* form #f 
+      (nm values)
+      [(define-values () (begin (quote-syntax (nm . rest)) (#%plain-app values)))
+       #t]
+      [_ #f])))
+
+(define (parse-def x)
+  (kernel-syntax-case x #f
+    [(define-values (nm ...) . rest) (syntax->list #'(nm ...))]
+    [_ #f]))
+
+(define (parse-syntax-def x)
+  (kernel-syntax-case x #f
+    [(define-syntaxes (nm ...) . rest) (syntax->list #'(nm ...))]
+    [_ #f]))
+
+
+(define (add-type-name! names)
+  (for-each register-type-name names))
+
+(define (parse-type-alias form)
+  (kernel-syntax-case* form #f 
+    (define-type-alias-internal values)
+    [(define-values () (begin (quote-syntax (define-type-alias-internal nm ty)) (#%plain-app values)))
+     (values #'nm #'ty)]
+    [_ (int-err "not define-type-alias")]))
+
+(define (type-check forms0)
+  (begin-with-definitions
+    (define forms (syntax->list forms0))
+    (define-values (type-aliases struct-defs stx-defs0 val-defs0 provs reqs)
+      (filter-multiple 
+       forms
+       (internal-syntax-pred define-type-alias-internal)
+       (lambda (e) (or ((internal-syntax-pred define-typed-struct-internal) e)
+                       ((internal-syntax-pred define-typed-struct/exec-internal) e)))
+       parse-syntax-def
+       parse-def 
+       provide?
+       define/fixup-contract?))
+    (for-each (compose register-type-alias parse-type-alias) type-aliases)   
+    ;; add the struct names to the type table
+    (for-each (compose add-type-name! names-of-struct) struct-defs)
+    ;; resolve all the type aliases, and error if there are cycles
+    (resolve-type-aliases parse-type)
+    ;; do pass 1, and collect the defintions
+    (define defs (filter list? (map tc-toplevel/pass1 forms)))
+    ;; separate the definitions into structures we'll handle for provides    
+    (define stx-defs (filter def-stx-binding? defs))
+    (define val-defs (filter def-binding? defs))
+    ;; typecheck the expressions and the rhss of defintions
+    (for-each tc-toplevel/pass2 forms)
+    ;; check that declarations correspond to definitions
+    (check-all-registered-types)
+    ;; compute the new provides
+    (with-syntax
+        ([((new-provs ...) ...) (map (generate-prov stx-defs val-defs) provs)])
+      #`(begin
+           #,(env-init-code)
+           #,(tname-env-init-code)
+           #,(talias-env-init-code)
+           (begin new-provs ... ...)))))
+
+;; typecheck a top-level form
+;; used only from #%top-interaction
+;; syntax -> void
+(define (tc-toplevel-form form)
+  (tc-toplevel/pass1 form)  
+  (tc-toplevel/pass2 form))
+
+
+
diff --git a/collects/typed-scheme/private/tc-utils.ss b/collects/typed-scheme/private/tc-utils.ss
new file mode 100644
index 0000000000..9b60c143af
--- /dev/null
+++ b/collects/typed-scheme/private/tc-utils.ss
@@ -0,0 +1,88 @@
+(module tc-utils mzscheme
+  (provide (all-defined))
+  (require (lib "list.ss") (lib "etc.ss")
+           "syntax-traversal.ss")
+
+  ;; a parameter representing the original location of the syntax being currently checked
+  (define current-orig-stx (make-parameter #'here))
+  (define orig-module-stx (make-parameter #f))
+  (define expanded-module-stx (make-parameter #f))
+  
+  ;; helper function, not currently used
+  (define (find-origin stx)
+    (cond [(syntax-property stx 'origin) => (lambda (orig)
+                                              (let ([r (reverse orig)])
+                                                (let loop ([r (reverse orig)])
+                                                  (if (null? r) #f
+                                                      (if (syntax-source (car r)) (car r)
+                                                          (loop (cdr r)))))))]
+          [else #f]))
+  
+  ;; do we print the fully-expanded syntax in error messages?
+  (define print-syntax? (make-parameter #f))
+  
+  
+  (define check-unreachable-code? (make-parameter #f))
+  
+  (define (locate-stx stx)
+    (define omodule (orig-module-stx))
+    (define emodule (expanded-module-stx))
+    ;(printf "orig: ~a~n" (syntax-object->datum omodule))
+    ;(printf "exp: ~a~n" (syntax-object->datum emodule))
+    ;(printf "stx (locate): ~a~n" (syntax-object->datum stx))
+    (look-for-in-orig omodule emodule stx))
+  
+  ;; produce a type error, using the current syntax
+  (define (tc-error msg . rest)
+    (define cur-stx 
+      (begin 
+        ;(printf "stx : ~a~n" (current-orig-stx))
+        (if (print-syntax?)
+            (current-orig-stx)
+            (locate-stx (current-orig-stx)))))
+    
+    ;(printf "Aliases: ~a~n" ((current-type-names)))
+    (raise-syntax-error 'typecheck (apply format msg rest) cur-stx cur-stx))
+  
+  ;; produce a type error, given a particular syntax
+  (define (tc-error/stx stx msg . rest)
+    (parameterize ([current-orig-stx stx])
+      (apply tc-error msg rest)))
+  
+  ;; check two identifiers to see if they have the same name
+  (define (symbolic-identifier=? a b)
+    (eq? (syntax-e a) (syntax-e b)))
+  
+  ;; parameter for currently-defined type aliases
+  ;; this is used only for printing type names
+  (define current-type-names (make-parameter (lambda () '())))
+  
+  ;; error for unbound variables
+  (define (lookup-fail e) (tc-error "unbound identifier ~a" e))  
+
+
+  ;; for reporting internal errors in the type checker
+  (define-struct (exn:fail:tc exn:fail) ())
+  
+  ;; raise an internal error - typechecker bug!
+  (define (int-err msg . args) 
+    (raise (make-exn:fail:tc (string-append "Internal Typechecker Error: " (apply format msg args))
+                             (current-continuation-marks))))
+  
+  (define-syntax (nyi stx)
+    (syntax-case stx ()
+      [(_ str)
+       (quasisyntax/loc stx (int-err "~a: not yet implemented: ~a" str #,(syntax/loc stx (this-expression-file-name))))]
+      [(_) (syntax/loc stx (nyi ""))]))
+
+  
+  ;; are we currently expanding in a typed module (or top-level form)?
+  (define typed-context? (box #f))
+  
+  ;; what type names have been referred to in this module?
+  (define type-name-references (make-parameter '()))
+  
+  (define (add-type-name-reference t)
+    (type-name-references (cons t (type-name-references))))
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/tool.ss b/collects/typed-scheme/private/tool.ss
new file mode 100644
index 0000000000..4071ff7f19
--- /dev/null
+++ b/collects/typed-scheme/private/tool.ss
@@ -0,0 +1,54 @@
+(module tool mzscheme
+  (require (lib "unit.ss")
+	   (lib "class.ss")
+	   (lib "tool.ss" "drscheme")
+           (lib "string-constant.ss" "string-constants")
+           (prefix r: "../typed-reader.ss"))
+  
+
+  (provide tool@)
+  
+  (define tool@
+    (unit
+      (import drscheme:tool^)
+      (export drscheme:tool-exports^)
+      
+      (define mbl% (drscheme:language:module-based-language->language-mixin
+		    (drscheme:language:simple-module-based-language->module-based-language-mixin 
+		     drscheme:language:simple-module-based-language%)))
+      
+      (define planet-module '(planet "typed-scheme.ss" ("plt" "typed-scheme.plt" 3)))
+
+      (define (typed-scheme-language% cl%)
+	(class* cl% (drscheme:language:simple-module-based-language<%>)
+	  (define/override (get-language-numbers)
+	    '(1000 -401))
+	  (define/override (get-language-name) "Typed Scheme")
+	  (define/override (get-language-position)
+	    (list (string-constant experimental-languages) "Typed Scheme"))
+	  (define/override (get-module) planet-module)
+          (define/override (get-reader) 
+	    (lambda (src port)
+       	      (let ([v (r:read-syntax src port)])
+                (if (eof-object? v)
+                  v
+                  (namespace-syntax-introduce v)))))
+ 	  (define/override (get-one-line-summary)
+	    "Scheme with types!")
+          (define/override (get-language-url) "http://www.ccs.neu.edu/~samth/typed-scheme.html")
+	  (define/override (enable-macro-stepper?) #t)
+          (define/override (use-namespace-require/copy?) #f)
+	  (super-new [module (get-module)] [language-position (get-language-position)])))
+      
+      (define (phase1) (void))
+      (define (phase2)
+        (drscheme:language-configuration:add-language 
+	 (make-object (typed-scheme-language%
+		       ((drscheme:language:get-default-mixin) 
+			mbl%)))))))
+  )
+      
+      
+  
+  
+  
diff --git a/collects/typed-scheme/private/type-alias-env.ss b/collects/typed-scheme/private/type-alias-env.ss
new file mode 100644
index 0000000000..33d6d82ef1
--- /dev/null
+++ b/collects/typed-scheme/private/type-alias-env.ss
@@ -0,0 +1,65 @@
+#lang scheme/base
+
+(require syntax/boundmap
+         "tc-utils.ss"
+         mzlib/trace
+         mzlib/plt-match)
+
+(provide register-type-alias
+         lookup-type-alias
+         resolve-type-aliases
+         register-resolved-type-alias
+         type-alias-env-map)
+
+(define-struct alias-def () #:inspector #f)
+(define-struct (unresolved alias-def) (stx [in-process #:mutable]) #:inspector #f)
+(define-struct (resolved alias-def) (ty) #:inspector #f)
+
+;; a mapping from id -> alias-def (where id is the name of the type)
+(define the-mapping 
+  (make-module-identifier-mapping))
+
+(define (mapping-put! id v) (module-identifier-mapping-put! the-mapping id v))
+
+;(trace mapping-put!)
+
+;; add a name to the mapping
+;; identifier type-stx -> void
+(define (register-type-alias id stx)
+  ;(printf "registering type ~a~n~a~n" (syntax-e id) id)
+  (mapping-put! id (make-unresolved stx #f)))
+
+(define (register-resolved-type-alias id ty)
+  (mapping-put! id (make-resolved ty)))
+
+(define (lookup-type-alias id parse-type [k (lambda () (tc-error "Unknown type alias: ~a" (syntax-e id)))])
+  (let/ec return
+    (match (module-identifier-mapping-get the-mapping id (lambda () (return (k))))
+      [(struct unresolved (stx #f))
+       (resolve-type-alias id parse-type)]
+      [(struct unresolved (stx #t)) 
+       (tc-error/stx stx "Recursive Type Alias Reference")]
+      [(struct resolved (t)) t])))
+
+(define (resolve-type-alias id parse-type)
+  (define v (module-identifier-mapping-get the-mapping id))  
+  (match v
+    [(struct unresolved (stx _))
+     (set-unresolved-in-process! v #t)
+     (let ([t (parse-type stx)])
+       (mapping-put! id (make-resolved t))
+       t)]
+    [(struct resolved (t))
+     t]))
+
+(define (resolve-type-aliases parse-type)
+  (module-identifier-mapping-for-each the-mapping (lambda (id _) (resolve-type-alias id parse-type))))
+
+;; map over the-mapping, producing a list
+;; (id type -> T) -> listof[T]
+(define (type-alias-env-map f)
+  (define sym (gensym))
+  (filter (lambda (e) (not (eq? sym e)))
+          (module-identifier-mapping-map the-mapping (lambda (id t) (if (resolved? t)
+                                                                        (f id (resolved-ty t))
+                                                                        sym)))))
diff --git a/collects/typed-scheme/private/type-annotation.ss b/collects/typed-scheme/private/type-annotation.ss
new file mode 100644
index 0000000000..3b61281ab7
--- /dev/null
+++ b/collects/typed-scheme/private/type-annotation.ss
@@ -0,0 +1,92 @@
+#lang scheme/base
+
+(require "type-rep.ss" "parse-type.ss" "tc-utils.ss" "subtype.ss" "utils.ss" "union.ss" "resolve-type.ss"
+         "type-env.ss")
+(require (lib "plt-match.ss"))
+(provide type-annotation
+         get-type
+         get-type/infer
+         type-label-symbol
+         type-ascrip-symbol
+         check-type)
+
+(define type-label-symbol 'type-label)
+(define type-ascrip-symbol 'type-ascription)    
+
+(define (print-size stx)
+  (syntax-case stx ()
+    [(a . b) (begin
+               (printf/log "Annotation Sexp Pair ~n")
+               (print-size #'a)
+               (print-size #'b))]      
+    [_ (printf/log "Annotation Sexp ~n" )]))
+
+;; get the type annotation of this syntax
+;; syntax -> Maybe[Type]
+(define (type-annotation stx)
+  (define (pt prop)
+    (print-size prop)
+    (if (syntax? prop)
+        (parse-type prop)
+        (parse-type/id stx prop)))
+  (cond       
+    [(syntax-property stx type-label-symbol) => pt]
+    [(syntax-property stx type-ascrip-symbol) => pt]
+    [(and (identifier? stx) (lookup-type stx (lambda () #f)))
+     =>
+     (lambda (t)
+       (maybe-finish-register-type stx)
+       t)]
+    [else #f]))
+
+(define (log/ann stx ty)
+  (printf/log "Required Annotated Variable: ~a ~a~n" (syntax-e stx) ty))
+(define (log/extra stx ty ty2)
+  (printf/log "Extra Annotated Variable: ~a ~a ~a~n" (syntax-e stx) ty ty2))
+(define (log/noann stx ty)
+  (printf/log "Unannotated Variable: ~a ~a~n" (syntax-e stx) ty))
+
+;; get the type annotation of this identifier, otherwise error
+;; identifier -> Type
+(define (get-type stx)
+  (parameterize
+      ([current-orig-stx stx])
+    (cond
+      [(type-annotation stx) => (lambda (x) 
+                                  (log/ann stx x)
+                                  x)]
+      [(not (syntax-original? stx)) 
+       (tc-error "untyped var: ~a" (syntax-e stx))]
+      [else
+       (tc-error "no type information on variable ~a" (syntax-e stx))])))
+
+;; get the type annotations on this list of identifiers
+;; if not all identifiers have annotations, return the supplied inferred type
+;; list[identifier] type -> list[type]
+(define (get-type/infer stxs e-type)
+  (match (list stxs e-type)
+    [(list '() (Values: '())) (list)]
+    [(list (list stx ...) (Values: (list ty ...)))
+     (map (lambda (stx ty)
+            (cond [(type-annotation stx) => (lambda (ann) (check-type stx ty ann) (log/extra stx ty ann) ann)]
+                  [else (log/noann stx ty) ty]))
+          stx ty)]      
+    [(list (list stx) ty)
+     (cond [(type-annotation stx) => (lambda (ann)
+                                       (check-type stx ty ann) 
+                                       (log/extra stx ty ann)
+                                       (list ann))]
+           [else (log/noann stx ty) (list ty)])]
+    [else (int-err "wrong type arity - get-type/infer ~a ~a" stxs e-type)]))
+
+
+;; check that e-type is compatible with ty in context of stx
+;; otherwise, error
+;; syntax type type -> void
+
+(define (check-type stx e-type ty)
+  (let ([stx* (current-orig-stx)])
+    (parameterize ([current-orig-stx stx])
+      (unless (subtype e-type ty)
+        ;(printf "orig-stx: ~a" (syntax->datum stx*))
+        (tc-error "Body had type:~n~a~nVariable had type:~n~a~n" e-type ty)))))
diff --git a/collects/typed-scheme/private/type-comparison.ss b/collects/typed-scheme/private/type-comparison.ss
new file mode 100644
index 0000000000..b421fd8625
--- /dev/null
+++ b/collects/typed-scheme/private/type-comparison.ss
@@ -0,0 +1,8 @@
+(module type-comparison mzscheme
+  (require "type-rep.ss" "type-utils.ss")
+  
+  (provide type-equal? tc-result-equal? type<? type-compare effects-equal?)
+  
+  
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/type-contract.ss b/collects/typed-scheme/private/type-contract.ss
new file mode 100644
index 0000000000..e366ad6dd6
--- /dev/null
+++ b/collects/typed-scheme/private/type-contract.ss
@@ -0,0 +1,131 @@
+(module type-contract mzscheme
+  
+  (provide type->contract define/fixup-contract? generate-contract-def change-contract-fixups)
+  
+  (require
+   "type-rep.ss"   
+   "parse-type.ss"
+   "utils.ss"      
+   "type-name-env.ss"
+   "require-contract.ss"
+   "internal-forms.ss"
+   "tc-utils.ss"
+   "resolve-type.ss"
+   "type-utils.ss"
+   mzlib/list   
+   (only "type-effect-convenience.ss" Any-Syntax))
+  
+  (require
+   (lib "plt-match.ss")
+   (lib "struct.ss" "syntax")
+   (lib "stx.ss" "syntax")
+   (lib "trace.ss")
+   (only (lib "contract.ss") -> ->* case-> cons/c flat-rec-contract)
+   (lib "etc.ss")           
+   (lib "struct.ss")
+   #;(lib "syntax-browser.ss" "macro-debugger"))
+  
+  (require-for-template mzscheme (lib "contract.ss") (only scheme/class object%))
+  
+  (define (define/fixup-contract? stx)
+    (syntax-property stx 'typechecker:contract-def))
+  
+  (define (generate-contract-def stx)
+    (define prop (syntax-property stx 'typechecker:contract-def))
+    (define typ (parse-type prop))
+    (syntax-case stx (define-values)
+      [(_ (n) __)
+       (with-syntax ([cnt (type->contract typ (lambda () (tc-error/stx prop "Type ~a could not be converted to a contract." typ)))])
+         (syntax/loc stx (define-values (n) cnt)))]
+      [_ (int-err "should never happen - not a define-values: ~a" (syntax-object->datum stx))]))
+  
+  (define (change-contract-fixups forms)
+    (map (lambda (e)
+           (if (not (define/fixup-contract? e))
+               e
+               (generate-contract-def e)))
+         (syntax->list forms)))
+  
+  
+  (define (type->contract ty fail)
+    (define vars (make-parameter '()))
+    (let/cc exit
+      (let t->c ([ty ty])
+        (match ty
+          [(or (App: _ _ _) (Name: _)) (t->c (resolve-once ty))]
+          [(Univ:) #'any/c]
+          ;; we special-case lists:
+          [(Mu: var (Union: (list (Value: '()) (Pair: elem-ty (F: var)))))
+           #`(listof #,(t->c elem-ty))]
+          [(? (lambda (e) (eq? Any-Syntax e))) #'syntax?]
+          [(Base: sym)
+           (case sym
+             [(Number) #'number?]
+             [(Boolean) #'boolean?]
+             [(Keyword) #'keyword?]
+             [(Port) #'port?]
+             [(Path) #'path?]
+             [(String) #'string?]
+             [(Symbol) #'symbol?]
+             [(Bytes) #'bytes?]
+             [(Void) #'void?]
+             [(Syntax) #'syntax?]
+             [(Output-Port) #'output-port?]
+             [(Input-Port) #'input-port?]
+             [(Char) #'char?]
+             [(Namespace) #'namespace?]
+             [else (int-err "Base type ~a cannot be converted to contract" sym)])]
+          [(Union: elems) 
+           (with-syntax 
+               ([cnts (map t->c elems)])
+             #;(printf "~a~n" (syntax-object->datum #'cnts))
+             #'(or/c . cnts))]
+          [(Function: arrs)
+           (let ()
+             (define (f a)
+               (define-values (dom* rngs* rst)
+                 (match a
+                   [(arr: dom (Values: rngs) #f _ _)
+                    (values (map t->c dom) (map t->c rngs) #f)]
+                   [(arr: dom rng #f _ _)
+                    (values (map t->c dom) (list (t->c rng)) #f)]
+                   [(arr: dom (Values: rngs) rst _ _)
+                    (values (map t->c dom) (map t->c rngs) (t->c rst))]
+                   [(arr: dom rng rst _ _)
+                    (values (map t->c dom) (list (t->c rng)) (t->c rst))]))
+               (with-syntax 
+                   ([(dom* ...) dom*]
+                    [(rng* ...) rngs*]
+                    [rst* rst])
+                 (if rst
+                     #'((dom* ...) (listof rst*) . ->* . (rng* ...))
+                     #'((dom* ...) . ->* . (rng* ...)))))
+             (let ([l (map f arrs)])
+               (if (and (pair? l) (null? (cdr l)))
+                   (car l)
+                   #`(case-> #,@l))))]
+          [(Vector: t)
+           #`(vectorof #,(t->c t))]
+          [(Pair: t1 t2)
+           #`(cons/c #,(t->c t1) #,(t->c t2))]
+          [(Opaque: p? cert)
+           #`(flat-contract #,(cert p?))]
+          [(F: v) (cond [(assoc v (vars)) => cadr]
+                        [else (int-err "unknown var: ~a" v)])]
+          [(Mu: n b)
+           (with-syntax ([(n*) (generate-temporaries (list n))])
+             (parameterize ([vars (cons (list n #'n*) (vars))])
+               #`(flat-rec-contract n* #,(t->c b))))]
+          [(Value: #f) #'false/c]    
+          [(Instance: _) #'(is-a?/c object%)]
+          [(Class: _ _ _) #'(subclass?/c object%)]
+          [(Value: '()) #'null?]
+          [(Syntax: (Base: 'Symbol)) #'identifier?]
+          [(Syntax: t)
+           (if (equal? ty Any-Syntax)
+               #`syntax?
+               #`(syntax/c #,(t->c t)))]
+          [(Value: v) #`(flat-named-contract #,(format "~a" v) (lambda (x) (equal? x #,v)))]
+          [else (exit (fail))]))))
+  
+  )
diff --git a/collects/typed-scheme/private/type-effect-convenience.ss b/collects/typed-scheme/private/type-effect-convenience.ss
new file mode 100644
index 0000000000..d12f0cbd58
--- /dev/null
+++ b/collects/typed-scheme/private/type-effect-convenience.ss
@@ -0,0 +1,231 @@
+(module type-effect-convenience scheme/base
+  
+  (require "type-rep.ss" 
+           "effect-rep.ss"
+           mzlib/plt-match
+           "type-comparison.ss"
+           "type-effect-printer.ss"
+           "union.ss"
+           "subtype.ss"
+           "type-utils.ss"
+           (lib "list.ss")
+           scheme/promise
+           (prefix-in 1: srfi/1)
+           (for-syntax scheme/base))
+  
+  (provide (all-defined-out))
+    
+  
+  (define (-vet id) (make-Var-True-Effect id))
+  (define (-vef id) (make-Var-False-Effect id))
+  
+  (define -rem make-Remove-Effect)
+  (define -rest make-Restrict-Effect)
+  
+  (define (var->type-eff eff)
+    (match eff
+      [(Var-True-Effect: v) (make-Remove-Effect (make-Value #f) v)]
+      [(Var-False-Effect: v) (make-Restrict-Effect (make-Value #f) v)]
+      [_ eff]))
+  
+  (define ((add-var v) eff)
+    (match eff
+      [(Latent-Var-True-Effect:) (-vet v)]
+      [(Latent-Var-False-Effect:) (-vef v)]
+      [(Latent-Restrict-Effect: t) (make-Restrict-Effect t v)]
+      [(Latent-Remove-Effect: t) (make-Remove-Effect t v)]
+      [(True-Effect:) eff]
+      [(False-Effect:) eff]
+      [_ (error 'internal-tc-error "can't add var to effect ~a" eff)]))
+  
+  (define-syntax ->
+    (syntax-rules (:)
+      [(_ dom ... rng)
+       (->* (list dom ...) rng)]
+      [(_ dom ... rng : eff1 eff2)
+       (->* (list dom ...) : eff1 eff2)]))
+  (define-syntax ->*
+    (syntax-rules (:)
+      [(_ dom rng)       
+       (make-Function (list (make-arr* dom rng)))]
+      [(_ dom rst rng)
+       (make-Function (list (make-arr* dom rng rst)))]
+      [(_ dom rng : eff1 eff2)
+       (make-Function (list (make-arr* dom rng #f eff1 eff2)))]
+      [(_ dom rst rng : eff1 eff2)
+       (make-Function (list (make-arr* dom rng rst eff1 eff2)))]))
+  (define-syntax cl->
+    (syntax-rules (:)
+      [(_ [(dom ...) rng] ...)
+       (make-Function (list (make-arr* (list dom ...) rng) ...))]
+      [(_ [(dom ...) rng : eff1 eff2] ...)
+       (make-Function (list (make-arr* (list dom ...) rng #f eff1 eff2) ...))]
+      [(_ [(dom ...) rng rst : eff1 eff2] ...)
+       (make-Function (list (make-arr* (list dom ...) rng rst eff1 eff2) ...))]))
+  (define (cl->* . args)
+    (define (funty-arities f)
+      (match f
+        [(Function: as) as]))
+    (make-Function (map car (map funty-arities args))))
+  
+  (define make-arr*
+    (case-lambda [(dom rng) (make-arr* dom rng #f (list) (list))]
+                 [(dom rng rest) (make-arr dom rng rest (list) (list))]
+                 [(dom rng rest eff1 eff2) (make-arr dom rng rest eff1 eff2)]))
+  
+  (define (make-promise-ty t)
+    (make-Struct (string->uninterned-symbol "Promise") #f (list t) #f))
+  
+  (define N (make-Base 'Number))
+  (define -Integer (make-Base 'Integer))
+  (define B (make-Base 'Boolean))
+  (define Sym (make-Base 'Symbol))
+  (define -Void (make-Base 'Void))
+  (define -Bytes (make-Base 'Bytes))
+  (define -Regexp (make-Base 'Regexp))
+  (define -PRegexp (make-Base 'PRegexp))
+  (define -Byte-Regexp (make-Base 'Byte-Regexp))
+  (define -Byte-PRegexp (make-Base 'Byte-PRegexp))
+  (define -String (make-Base 'String))
+  (define -Keyword (make-Base 'Keyword))
+  (define -Char (make-Base 'Char))
+  (define -Syntax make-Syntax)
+  (define -Prompt-Tag (make-Base 'Prompt-Tag))
+  (define -Cont-Mark-Set (make-Base 'Continuation-Mark-Set))
+  (define -Path (make-Base 'Path))
+  (define -Namespace (make-Base 'Namespace))
+  (define -Output-Port (make-Base 'Output-Port))
+  (define -Input-Port (make-Base 'Input-Port))  
+  
+  (define -HT make-Hashtable)
+  (define -Promise make-promise-ty)
+
+  (define Univ (make-Univ))
+  
+  (define-syntax -v 
+    (syntax-rules ()
+      [(_ x) (make-F 'x)]))
+  
+  (define-syntax -poly
+    (syntax-rules ()
+      [(_ (vars ...) ty)
+       (let ([vars (-v vars)] ...)
+         (make-Poly (list 'vars ...) ty))]))
+  
+  (define-syntax -mu
+    (syntax-rules ()
+      [(_ var ty)
+       (let ([var (-v var)])
+         (make-Mu 'var ty))]))
+  
+  
+  (define -values make-Values)
+  
+  ;; produce the appropriate type of a list of types
+  ;; that is - if there is exactly one type, just produce it, otherwise produce a values-ty
+  ;; list[type] -> type
+  (define (list->values-ty l)
+    (if (= 1 (length l)) (car l) (-values l)))
+  
+  (define-syntax *Un
+    (syntax-rules ()
+      [(_ . args) (make-Union (list . args))]))
+
+  
+  (define -pair make-Pair)
+  (define -base make-Base)
+  
+  (define -struct make-Struct)
+  (define -val make-Value)
+      
+  (define (make-Listof elem) (-mu list-rec (*Un (-val null) (-pair elem list-rec))))
+  (define -Listof (-poly (list-elem) (make-Listof list-elem)))
+  
+  (define -lst make-Listof)
+  (define -Sexp (-mu x (*Un Sym N B -String (-val null) (-pair x x))))
+  (define -Port (*Un -Input-Port -Output-Port))
+  
+  (define (-lst* . args) (if (null? args)
+                             (-val null)
+                             (-pair (car args) (apply -lst* (cdr args)))))
+  
+
+  #;(define NE (-mu x (Un N (make-Listof x))))
+  (define -NE (-mu x (*Un N (-pair x (-pair Sym (-pair x (-val null)))))))
+  
+  (define (Un/eff . args)
+    (apply Un (map tc-result-t args)))
+
+  (define -Param make-Param)
+  
+  (define make-pred-ty
+    (case-lambda 
+      [(in out t)
+       (->* in out : (list (make-Latent-Restrict-Effect t)) (list (make-Latent-Remove-Effect t)))]
+      [(t) (make-pred-ty (list Univ) B t)]))
+
+  (define -Pathlike (*Un -Path -String))
+  (define -Pathlike* (*Un (-val 'up) (-val 'same) -Path -String))
+  (define -Pattern (*Un -String -Bytes -Regexp -Byte-Regexp -PRegexp -Byte-PRegexp))
+  (define -Byte N)
+  
+  (define (-Tuple l)
+    (foldr -pair (-val '()) l))
+  
+  (define Any-Syntax 
+    (-mu x
+         (-Syntax (*Un 
+                       (-lst x)                       
+                       (-mu y (*Un x (-pair x y)))
+                       (make-Vector x)
+                       (make-Box x)
+                       N
+                       B
+                       -String
+                       Sym))))
+  
+  (define Ident (-Syntax Sym))
+  
+  ;; DO NOT USE if t contains #f
+  (define (-opt t) (*Un (-val #f) t))
+  
+  (define-syntax (make-env stx)
+    (syntax-case stx ()
+      [(_ e ...)
+       #`(list
+          #,@(map (lambda (e)
+                    (syntax-case e ()
+                      [(nm ty)
+                       (identifier? #'nm)
+                       #`(list  #'nm ty)]
+                      [(e ty extra-mods ...)
+                       #'(list (let ([new-ns
+                                      (let* ([ns (make-empty-namespace)])
+                                        (namespace-attach-module (current-namespace)
+                                                                 'scheme/base
+                                                                 ns)
+                                        ns)])
+                                 (parameterize ([current-namespace new-ns])
+                                   (namespace-require 'extra-mods) ...
+                                   e))
+                               ty)]))
+                  (syntax->list #'(e ...))))]))
+  
+  ;; if t is of the form (Pair t* (Pair t* ... (Listof t*)))
+  ;; return t*
+  ;; otherwise, return t
+  ;; generalize : Type -> Type
+  (define (generalize t)
+    (let/ec exit
+      (let loop ([t* t])
+        (match t*
+          [(Mu: var (Union: (list (Value: '()) (Pair: _ (F: var))))) t*]
+          [(Pair: t1 t2)
+           (let ([t-new (loop t2)])
+             (if (type-equal? (-lst t1) t-new)
+                 t-new
+                 (exit t)))]
+          [_ (exit t)]))))
+
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/type-effect-printer.ss b/collects/typed-scheme/private/type-effect-printer.ss
new file mode 100644
index 0000000000..9424048944
--- /dev/null
+++ b/collects/typed-scheme/private/type-effect-printer.ss
@@ -0,0 +1,145 @@
+(module type-effect-printer mzscheme
+  (require "type-rep.ss" "effect-rep.ss" "rep-utils.ss" "tc-utils.ss")
+  (require (lib "plt-match.ss"))
+  (require "planet-requires.ss")  
+  
+  ;; do we attempt to find instantiations of polymorphic types to print? 
+  ;; FIXME - currently broken
+  (define print-poly-types? #f)
+  ;; do we use simple type aliases in printing
+  (define print-aliases #t)
+
+  ;; does t have a type name associated with it currently?
+  ;; has-name : Type -> Maybe[Symbol]
+  (define (has-name? t) 
+    (define ns ((current-type-names)))
+    (let/cc return
+      (unless print-aliases
+        (return #f))
+      (for-each
+       (lambda (pair)
+         (cond [(eq? t (cdr pair))
+                (return (car pair))]))
+       ns)
+      #f))
+      
+  ;; print out an effect
+  ;; print-effect : Effect Port Boolean -> Void
+  (define (print-effect c port write?)
+    (define (fp . args) (apply fprintf port args))    
+    (match c
+      [(Restrict-Effect: t v) (fp "(restrict ~a ~a)" t (syntax-e v))]
+      [(Remove-Effect: t v) (fp "(remove ~a ~a)" t (syntax-e v))]
+      [(Latent-Restrict-Effect: t) (fp "(restrict ~a)" t)]
+      [(Latent-Remove-Effect: t) (fp "(remove ~a)" t)]
+      [(Latent-Var-True-Effect:) (fp "(var #t)")]
+      [(Latent-Var-False-Effect:) (fp "(var #f)")]
+      [(True-Effect:) (fp "T")]
+      [(False-Effect:) (fp "F")]
+      [(Var-True-Effect: v) (fp "(var #t ~a)" (syntax-e v))]
+      [(Var-False-Effect: v) (fp "(var #f ~a)" (syntax-e v))]))
+  
+  
+  ;; print out a type
+  ;; print-type : Type Port Boolean -> Void
+  (define (print-type c port write?)
+    (define (fp . args) (apply fprintf port args)) 
+    (define (print-arr a)
+      (match a
+        [(top-arr:)
+         (fp "Procedure")]
+        [(arr: dom rng rest thn-eff els-eff)
+         (fp "(")
+         (for-each (lambda (t) (fp "~a " t)) dom)
+         (when rest
+           (fp "~a .. " rest))
+         (fp "-> ~a" rng)
+         (unless (and (null? thn-eff) (null? els-eff))
+           (fp " : ~a ~a" thn-eff els-eff))
+         (fp ")")]))
+    (define (tuple? t)
+      (match t
+        [(Pair: a (? tuple?)) #t]
+        [(Value: '()) #t]
+        [_ #f]))
+    (define (tuple-elems t)
+      (match t
+        [(Pair: a e) (cons a (tuple-elems e))]
+        [(Value: '()) null]))
+    ;(fp "~a~n" (Type-seq c))
+    (match c 
+      [(Univ:) (fp "Any")]
+      [(? has-name?) (fp "~a" (has-name? c))]
+      ;; names are just the printed as the original syntax
+      [(Name: stx) (fp "[~a]" (syntax-e stx))]
+      [(App: rator rands stx) 
+       (fp "~a" (cons rator rands))]
+      ;; special cases for lists
+      [(Mu: var (Union: (list (Value: '()) (Pair: elem-ty (F: var)))))
+       (fp "(Listof ~a)" elem-ty)]
+      [(Mu: var (Union: (list (Pair: elem-ty (F: var)) (Value: '()))))
+       (fp "(Listof ~a)" elem-ty)]
+      [(Value: v) (cond [(or (symbol? v) (null? v))
+                         (fp "'~a" v)]
+                        [else (fp "~a" v)])]
+      [(? tuple? t)
+       (fp "~a" (cons 'List (tuple-elems t)))]
+      [(Base: n) (fp "~a" n)]      
+      [(Opaque: pred _) (fp "(Opaque ~a)" (syntax-object->datum pred))]
+      [(Struct: 'Promise par (list fld) proc) (fp "(Promise ~a)" fld)]      
+      [(Struct: nm par flds proc) 
+        (fp "#(struct:~a ~a" nm flds)
+        (when proc
+          (fp " ~a" proc))
+        (fp ")")]
+      [(Function: arities)
+       (let ()         
+         (match arities
+           [(list) (fp "(case-lambda)")]
+           [(list a) (print-arr a)]
+           [(list a ...) (fp "(case-lambda ") (for-each print-arr a) (fp ")")]))]
+      [(arr: _ _ _ _ _) (print-arr c)]
+      [(Vector: e) (fp "(Vectorof ~a)" e)]
+      [(Box: e) (fp "(Box ~a)" e)]
+      [(Union: elems) (fp "~a" (cons 'U elems))]
+      [(Pair: l r) (fp "(Pair ~a ~a)" l r)]
+      [(F: nm) (fp "<~a>" nm)]      
+      [(Values: (list v ...)) (fp "~a" (cons 'values v))]
+      [(Param: in out) 
+       (if (equal? in out)
+           (fp "(Paramter ~a)" in)           
+           (fp "(Parameter ~a ~a)" in out))]
+      [(Hashtable: k v) (fp "(HashTable ~a ~a)" k v)]
+      #;
+      [(Poly-unsafe: n b) (fp "(unsafe-poly ~a ~a ~a)" (Type-seq c) n b)]
+      [(Poly-names: names body) 
+       #;(fprintf (current-error-port) "POLY SEQ: ~a~n" (Type-seq body))
+       (fp "(All ~a ~a)" names body)]
+      #;
+      [(Mu-unsafe: b) (fp "(unsafe-mu ~a ~a)" (Type-seq c) b)]
+      [(Mu: x (Syntax: (Union: (list
+                                (Base: 'Number) 
+                                (Base: 'Boolean)
+                                (Base: 'Symbol)
+                                (Base: 'String)
+                                (Mu: var (Union: (list (Value: '()) (Pair: (F: x) (F: var)))))
+                                (Mu: y (Union: (list (F: x) (Pair: (F: x) (F: y)))))
+                                (Vector: (F: x))
+                                (Box: (F: x))))))
+       (fp "SyntaxObject")]
+      [(Mu-name: name body) (fp "(mu ~a ~a ~a)" (Type-seq c) name body)]
+      ;; FIXME - this should not be used
+      #;
+      [(Scope: sc) (fp "(Scope ~a)" sc)]
+      #;
+      [(B: idx) (fp "(B ~a)" idx)]      
+      [(Syntax: t) (fp "(Syntax ~a)" t)]
+      [(Instance: t) (fp "(Instance ~a)" t)]
+      [(Class: pf nf ms) (fp "(Class)")]
+      [else (fp "Unknown Type: ~a" (struct->vector c))]
+      ))
+  
+  (set-box! print-type* print-type)
+  (set-box! print-effect* print-effect)
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/type-env.ss b/collects/typed-scheme/private/type-env.ss
new file mode 100644
index 0000000000..c42d110d04
--- /dev/null
+++ b/collects/typed-scheme/private/type-env.ss
@@ -0,0 +1,61 @@
+#lang scheme/base
+
+(require (lib "boundmap.ss" "syntax")
+         "tc-utils.ss")
+
+(provide register-type
+         finish-register-type
+         maybe-finish-register-type
+         register-type/undefined
+         lookup-type
+         register-types
+         check-all-registered-types
+         type-env-map)
+
+;; module-identifier-mapping from id -> type or Box[type]
+;; where id is a variable, and type is the type of the variable
+;; if the result is a box, then the type has not actually been defined, just registered
+(define the-mapping (make-module-identifier-mapping))
+
+;; add a single type to the mapping
+;; identifier type -> void
+(define (register-type id type)
+  (module-identifier-mapping-put! the-mapping id type))
+
+;; add a single type to the mapping
+;; identifier type -> void
+(define (register-type/undefined id type)
+  (module-identifier-mapping-put! the-mapping id (box type)))
+
+;; add a bunch of types to the mapping
+;; listof[id] listof[type] -> void
+(define (register-types ids types)
+  (for-each register-type ids types))
+
+;; given an identifier, return the type associated with it
+;; if none found, calls lookup-fail
+;; identifier -> type 
+(define (lookup-type id [fail-handler (lambda () (lookup-fail (syntax-e id)))])
+  (let ([v (module-identifier-mapping-get the-mapping id fail-handler)])
+    (if (box? v) (unbox v) v)))
+
+(define (maybe-finish-register-type id)
+  (let ([v (module-identifier-mapping-get the-mapping id)])
+    (if (box? v)
+        (register-type id (unbox v))
+        #f)))
+
+(define (finish-register-type id)
+  (unless (maybe-finish-register-type id)
+    (int-err "finishing type that was already finished: ~a" (syntax-e id))))
+
+(define (check-all-registered-types)
+  (module-identifier-mapping-for-each 
+   the-mapping 
+   (lambda (id e) 
+     (when (box? e) (tc-error/stx id "Declaration for ~a provided, but with no definition" (syntax-e id))))))
+
+;; map over the-mapping, producing a list
+;; (id type -> T) -> listof[T]  
+(define (type-env-map f)
+  (module-identifier-mapping-map the-mapping f))
diff --git a/collects/typed-scheme/private/type-environments.ss b/collects/typed-scheme/private/type-environments.ss
new file mode 100644
index 0000000000..54d5b008b2
--- /dev/null
+++ b/collects/typed-scheme/private/type-environments.ss
@@ -0,0 +1,60 @@
+(module type-environments mzscheme
+  
+  (provide current-tvars
+           extend
+           lookup
+           make-empty-env
+           extend-env
+           extend/values
+           initial-tvar-env)
+  
+  (require (lib "plt-match.ss")
+           (lib "list.ss")
+           "tc-utils.ss")
+  
+  ;; eq? has the type of equal?, and l is an alist (with conses!)
+  (define-struct env (eq? l))
+  
+  ;; the initial type variable environment - empty
+  ;; this is used in the parsing of types
+  (define initial-tvar-env (make-env eq? '()))
+
+  ;; a parameter for the current type variables
+  (define current-tvars (make-parameter initial-tvar-env))  
+  
+  (define (make-empty-env p?) (make-env p? '()))
+  
+
+  ;; extend that works on single arguments
+  (define (extend e k v) 
+    (match e
+      [(struct env (f l)) (make-env f (cons (cons k v) l))]
+      [_ (int-err "extend: expected environment, got ~a" e)]))
+    
+  (define (extend-env ks vs e)
+    (match e
+      [(struct env (f l)) (make-env f (append (map cons ks vs) l))]
+      [_ (int-err "extend-env: expected environment, got ~a" e)]))
+  
+  (define (lookup e key fail)
+    (match e
+      [(struct env (f? l))
+       (let loop ([l l])
+         (cond [(null? l) (fail key)]
+               [(f? (caar l) key) (cdar l)]
+               [else (loop (cdr l))]))]
+      [_ (int-err "lookup: expected environment, got ~a" e)]))
+    
+  
+  ;; takes two lists of sets to be added, which are either added one at a time, if the 
+  ;; elements are not lists, or all at once, if the elements are lists
+  (define (extend/values kss vss env)
+    (foldr (lambda (ks vs env) 
+             (cond [(and (list? ks) (list? vs))                                      
+                    (extend-env ks vs env)]
+                   [(or (list? ks) (list? vs))
+                    (int-err "not both lists in extend/values: ~a ~a" ks vs)]
+                   [else (extend-env (list ks) (list vs) env)]))
+           env kss vss))
+
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/type-name-env.ss b/collects/typed-scheme/private/type-name-env.ss
new file mode 100644
index 0000000000..3031f28ada
--- /dev/null
+++ b/collects/typed-scheme/private/type-name-env.ss
@@ -0,0 +1,44 @@
+#lang scheme/base
+
+(require syntax/boundmap
+         mzlib/trace
+         "tc-utils.ss")
+
+(provide register-type-name
+         lookup-type-name
+         register-type-names
+         type-name-env-map)
+
+;; a mapping from id -> type (where id is the name of the type)
+(define the-mapping 
+  (make-module-identifier-mapping))
+
+(define (mapping-put! id v) (module-identifier-mapping-put! the-mapping id v))
+;(trace mapping-put!)
+
+;; add a name to the mapping
+;; identifier Type -> void
+(define (register-type-name id [type #t])
+  ;(printf "registering type ~a~n~a~n" (syntax-e id) id)
+  (mapping-put! id type))
+
+;; add a bunch of names to the mapping
+;; listof[identifier] listof[type] -> void
+(define (register-type-names ids types)
+  (for-each register-type-name ids types))
+
+;; given an identifier, return the type associated with it
+;; optional argument is failure continuation - default calls lookup-fail
+;; identifier (-> error) -> type 
+(define (lookup-type-name id [k (lambda () (lookup-fail (syntax-e id)))])
+  (begin0
+    (module-identifier-mapping-get the-mapping id k)
+    (add-type-name-reference id)))
+
+
+;; map over the-mapping, producing a list
+;; (id type -> T) -> listof[T]
+(define (type-name-env-map f)
+  (module-identifier-mapping-map the-mapping f))
+
+
diff --git a/collects/typed-scheme/private/type-rep.ss b/collects/typed-scheme/private/type-rep.ss
new file mode 100644
index 0000000000..0c7c274930
--- /dev/null
+++ b/collects/typed-scheme/private/type-rep.ss
@@ -0,0 +1,434 @@
+#lang scheme/base
+  
+  (require (lib "plt-match.ss"))
+  (require (lib "etc.ss") (lib "list.ss"))
+  (require "planet-requires.ss" "rep-utils.ss" "effect-rep.ss" "tc-utils.ss"
+           "free-variance.ss")
+  (require (prefix-in 1: (lib "list.ss" "srfi" "1"))
+           (lib "trace.ss")
+           (for-syntax scheme/base))
+  
+  (define name-table (make-hash-table 'weak))
+  
+  ;; Name = Symbol
+  
+  ;; Type is defined in rep-utils.ss
+  
+  ;; t must be a Type
+  (dt Scope (t))
+  
+  ;; i is an nat
+  (dt B (i)
+      [#:frees empty-hash-table (make-immutable-hash-table (list (cons i Covariant)))]
+      [#:fold-rhs #:base])
+  
+  ;; n is a Name
+  (dt F (n) [#:frees (make-immutable-hash-table (list (cons n Covariant))) empty-hash-table] [#:fold-rhs #:base])
+  
+  ;; id is an Identifier
+  (dt Name (id) [#:intern (hash-id id)] [#:frees #f] [#:fold-rhs #:base])
+    
+  ;; rator is a type
+  ;; rands is a list of types
+  ;; stx is the syntax of the pair of parens
+  (dt App (rator rands stx)
+      [#:intern (list rator rands)]
+      [#:frees (combine-frees (map free-vars* (cons rator rands)))
+               (combine-frees (map free-idxs* (cons rator rands)))]
+      [#:fold-rhs (*App (type-rec-id rator)
+                        (map type-rec-id rands)
+                        stx)])
+  
+  ;; left and right are Types
+  (dt Pair (left right))
+  
+  ;; elem is a Type
+  (dt Vector (elem) [#:frees (make-invariant (free-vars* elem)) (make-invariant (free-idxs* elem))])
+  
+  ;; elem is a Type
+  (dt Box (elem) [#:frees (make-invariant (free-vars* elem)) (make-invariant (free-idxs* elem))])  
+  
+  ;; name is a Symbol (not a Name)
+  (dt Base (name) [#:frees #f] [#:fold-rhs #:base])
+  
+  ;; body is a Scope
+  (dt Mu (body) #:no-provide [#:frees (free-vars* body) (without-below 1 (free-idxs* body))]
+      [#:fold-rhs (*Mu (*Scope (type-rec-id (Scope-t body))))])    
+  
+  ;; n is how many variables are bound here
+  ;; body is a Scope
+  (dt Poly (n body) #:no-provide [#:frees (free-vars* body) (without-below n (free-idxs* body))]
+      [#:fold-rhs (let ([body* (remove-scopes n body)])
+                    (*Poly n (add-scopes n (type-rec-id body*))))])
+  
+  ;; pred : identifier
+  ;; cert : syntax certifier
+  (dt Opaque (pred cert) [#:intern (hash-id pred)] [#:frees #f] [#:fold-rhs #:base])
+  
+  ;; name : symbol
+  ;; parent : Struct
+  ;; flds : Listof[Type]
+  ;; proc : Function Type
+  (dt Struct (name parent flds proc) 
+      [#:frees (combine-frees (map free-vars* (append (if proc (list proc) null) (if parent (list parent) null) flds)))
+               (combine-frees (map free-idxs* (append (if proc (list proc) null) (if parent (list parent) null) flds)))]
+      [#:fold-rhs (*Struct name 
+                           (and parent (type-rec-id parent))
+                           (map type-rec-id flds)
+                           (and proc (type-rec-id proc)))])
+  
+  ;; dom : Listof[Type]
+  ;; rng : Type
+  ;; rest : Type
+  ;; thn-eff : Effect
+  ;; els-eff : Effect
+  ;; arr is NOT a Type
+  (dt arr (dom rng rest thn-eff els-eff)
+      [#:frees (combine-frees (append (map flip-variances (map free-vars* dom)) 
+                                      (map free-vars* (append (list rng) 
+                                                              (if rest (list rest) null)
+                                                              thn-eff
+                                                              els-eff))))
+               (combine-frees (append (map flip-variances (map free-idxs* dom))
+                                      (map free-idxs* (append (list rng) 
+                                                              (if rest (list rest) null)
+                                                              thn-eff
+                                                              els-eff))))]
+      [#:fold-rhs (*arr (map type-rec-id dom)
+                        (type-rec-id rng)
+                        (and rest (type-rec-id rest))
+                        (map effect-rec-id thn-eff)
+                        (map effect-rec-id els-eff))])
+  
+  ;; top-arr is the supertype of all function types
+  (dt top-arr ()
+      [#:frees #f] [#:fold-rhs #:base])
+  
+  ;; arities : Listof[arr]
+  (dt Function (arities) [#:frees (combine-frees (map free-vars* arities))
+                                  (combine-frees (map free-idxs* arities))]
+      [#:fold-rhs (*Function (map type-rec-id arities))])
+  
+  ;; v : Scheme Value
+  (dt Value (v) [#:frees #f] [#:fold-rhs #:base])
+  
+  ;; elems : Listof[Type]
+  (dt Union (elems) [#:frees (combine-frees (map free-vars* elems))
+                             (combine-frees (map free-idxs* elems))]
+      [#:fold-rhs ((unbox union-maker) (map type-rec-id elems))])
+  
+  (dt Univ () [#:frees #f] [#:fold-rhs #:base])
+  
+  ;; types : Listof[Type]
+  (dt Values (types) [#:frees (combine-frees (map free-vars* types))
+                              (combine-frees (map free-idxs* types))]
+      [#:fold-rhs (*Values (map type-rec-id types))])
+  
+  ;; in : Type
+  ;; out : Type
+  (dt Param (in out))
+  
+  ;; key : Type
+  ;; value : Type
+  (dt Hashtable (key value))
+  
+  ;; t : Type
+  (dt Syntax (t))
+  
+  ;; pos-flds  : (Listof Type)
+  ;; name-flds : (Listof (Tuple Symbol Type Boolean))
+  ;; methods   : (Listof (Tuple Symbol Function))
+  (dt Class (pos-flds name-flds methods)
+      [#:frees (combine-frees
+                (map free-vars* (append pos-flds 
+                                        (map cadr name-flds)
+                                        (map cadr methods))))
+               (combine-frees
+                (map free-idxs* (append pos-flds 
+                                        (map cadr name-flds)
+                                        (map cadr methods))))]
+      
+      [#:fold-rhs (match (list pos-flds name-flds methods)
+                    [(list
+                      pos-tys 
+                      (list (list init-names init-tys) ___)
+                      (list (list mname mty) ___))
+                     (*Class
+                      (map type-rec-id pos-tys)
+                      (map list
+                           init-names
+                           (map type-rec-id init-tys))
+                      (map list mname (map type-rec-id mty)))])])
+  
+  ;; cls : Class
+  (dt Instance (cls))
+  
+  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+  
+  ;; Ugly hack - should use units
+  
+  (define union-maker (box #f))
+  
+  (define (set-union-maker! v) (set-box! union-maker v))
+  
+  (provide set-union-maker!)
+  
+  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+  
+  ;; remove-dups: List[Type] -> List[Type]
+  ;; removes duplicate types from a SORTED list
+  (define (remove-dups types)
+    (cond [(null? types) types]
+          [(null? (cdr types)) types]
+          [(type-equal? (car types) (cadr types)) (remove-dups (cdr types))]
+          [else (cons (car types) (remove-dups (cdr types)))]))
+  
+  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; type/effect fold
+
+(define-syntaxes (type-case effect-case)
+  (let ()
+    (define (mk ht)
+      (lambda (stx)
+        (let ([ht (hash-table-copy ht)])
+          (define (mk-matcher kw) 
+            (datum->syntax stx (string->symbol (string-append (keyword->string kw) ":"))))
+          (define (add-clause cl)
+            (syntax-case cl ()
+              [(kw #:matcher mtch pats ... expr)
+               (hash-table-put! ht (syntax-e #'kw) (list #'mtch 
+                                                         (syntax/loc cl (pats ...))
+                                                         (lambda (tr er) #'expr)))]
+              [(kw pats ... expr) 
+               (hash-table-put! ht (syntax-e #'kw) (list (mk-matcher (syntax-e #'kw)) 
+                                                         (syntax/loc cl (pats ...))
+                                                         (lambda (tr er) #'expr)))]))
+          (define rid #'type-rec-id)
+          (define erid #'effect-rec-id)
+          (define (gen-clause k v)
+            (define match-ex (car v))
+            (define pats (cadr v))
+            (define body-f (caddr v))
+            (define pat (quasisyntax/loc pats (#,match-ex  . #,pats)))
+            (define cl (quasisyntax/loc match-ex (#,pat #,(body-f rid erid))))
+            cl)
+          (syntax-case stx ()
+            [(tc rec-id ty [kw pats ... es] ...)
+             #;(andmap (lambda (k) (keyword? (syntax-e k))) (syntax->list #'(kw ...)))
+             (syntax/loc stx (tc rec-id (lambda (e) (sub-eff rec-id e)) ty [kw pats ... es] ...))]
+            [(tc rec-id e-rec-id ty clauses  ...)
+             (begin 
+               (map add-clause (syntax->list #'(clauses ...)))
+               (with-syntax ([old-rec-id type-rec-id])
+                 #`(let ([#,rid rec-id]
+                         [#,erid e-rec-id]
+                         [#,fold-target ty])
+                     ;; then generate the fold
+                     #,(quasisyntax/loc stx
+                         (match #,fold-target
+                           #,@(hash-table-map ht gen-clause))))))]))))
+    (values (mk type-name-ht) (mk effect-name-ht))))
+
+(provide type-case effect-case)
+  
+  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+    
+  
+  ;; sub-eff : (Type -> Type) Eff -> Eff
+  (define (sub-eff sb eff)
+    (effect-case sb eff))  
+  
+  (define (add-scopes n t)
+    (if (zero? n) t
+        (add-scopes (sub1 n) (*Scope t))))
+  
+  (define (remove-scopes n sc)
+    (if (zero? n) 
+        sc
+        (match sc
+          [(Scope: sc*) (remove-scopes (sub1 n) sc*)]
+          [_ (int-err "Tried to remove too many scopes: ~a" sc)])))
+  
+  ;; abstract-many : Names Type -> Scope^n 
+  ;; where n is the length of names  
+  (define (abstract-many names ty)
+    (define (nameTo name count type)
+      (let loop ([outer 0] [ty type])
+        (define (sb t) (loop outer t))
+        (type-case 
+         sb ty
+         [#:F name* (if (eq? name name*) (*B (+ count outer)) ty)]
+         ;; necessary to avoid infinite loops
+         [#:Union elems (*Union (remove-dups (sort (map sb elems) type<?)))]
+         [#:Mu (Scope: body) (*Mu (*Scope (loop (add1 outer) body)))]
+         [#:Poly n body* 
+                 (let ([body (remove-scopes n body*)])
+                   (*Poly n (*Scope (loop (+ n outer) body))))])))
+    (let ([n (length names)])
+      (let loop ([ty ty] [names names] [count (sub1 n)])
+        (if (zero? count)
+            (add-scopes n (nameTo (car names) 0 ty))
+            (loop (nameTo (car names) count ty)
+                  (cdr names)
+                  (sub1 count))))))
+  
+  ;; instantiate-many : List[Type] Scope^n -> Type 
+  ;; where n is the length of types  
+  (define (instantiate-many images sc)
+    (define (replace image count type)
+      (let loop ([outer 0] [ty type])
+        (define (sb t) (loop outer t))
+        (type-case 
+         sb ty
+         [#:B idx (if (= (+ count outer) idx)
+                      image
+                      ty)]      
+         ;; necessary to avoid infinite loops
+         [#:Union elems (*Union (remove-dups (sort (map sb elems) type<?)))]
+         [#:Mu (Scope: body) (*Mu (*Scope (loop (add1 outer) body)))]
+         [#:Poly n body* 
+                 (let ([body (remove-scopes n body*)])
+                   (*Poly n (*Scope (loop (+ n outer) body))))])))
+    (let ([n (length images)])
+      (let loop ([ty (remove-scopes n sc)] [images images] [count (sub1 n)])
+        (if (zero? count)
+            (replace (car images) 0 ty)
+            (loop (replace (car images) count ty)
+                  (cdr images)
+                  (sub1 count))))))
+  
+  (define (abstract name ty)
+    (abstract-many (list name) ty))
+  
+  (define (instantiate type sc)
+    (instantiate-many (list type) sc))
+  
+  #;(trace instantiate-many abstract-many)
+  
+  ;; the 'smart' constructor
+  (define (Mu* name body)    
+    (let ([v (*Mu (abstract name body))])
+      (hash-table-put! name-table v name)
+      v))
+  
+  ;; the 'smart' destructor
+  (define (Mu-body* name t)
+    (match t
+      [(Mu: scope)
+       (instantiate (*F name) scope)]))
+  
+  ;; the 'smart' constructor
+  (define (Poly* names body)
+    (if (null? names) body
+        (let ([v (*Poly (length names) (abstract-many names body))])
+          (hash-table-put! name-table v names)
+          v)))
+  
+  ;; the 'smart' destructor
+  (define (Poly-body* names t)
+    (match t
+      [(Poly: n scope)
+       (unless (= (length names) n)
+         (error "Wrong number of names"))
+       (instantiate-many (map *F names) scope)]))
+  
+  (print-struct #t)
+  
+  (define-match-expander Mu-unsafe:
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ bp) #'(? Mu? (app (lambda (t) (Scope-t (Mu-body t))) bp))])))
+  
+  (define-match-expander Poly-unsafe:
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ n bp) #'(? Poly? (app (lambda (t) (list (Poly-n t) (Poly-body t))) (list n bp)))])))
+  
+  (define-match-expander Mu:*
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ np bp)
+         #'(? Mu?
+              (app (lambda (t) (let ([sym (gensym)])
+                                 (list sym (Mu-body* sym t))))
+                   (list np bp)))])))
+  
+  (define-match-expander Mu-name:
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ np bp)
+         #'(? Mu?
+              (app (lambda (t) (let ([sym (hash-table-get name-table t (lambda _ (gensym)))])
+                                 (list sym (Mu-body* sym t))))
+                   (list np bp)))])))
+  
+  ;; This match expander wraps the smart constructor
+  ;; names are generated with gensym
+  (define-match-expander Poly:*
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ nps bp)
+         #'(? Poly?
+              (app (lambda (t) 
+                     (let* ([n (Poly-n t)]
+                            [syms (build-list n (lambda _ (gensym)))])
+                       (list syms (Poly-body* syms t))))
+                   (list nps bp)))])))
+  
+  ;; This match expander uses the names from the hashtable  
+  (define-match-expander Poly-names:
+    (lambda (stx)
+      (syntax-case stx ()
+        [(_ nps bp)
+         #'(? Poly?
+              (app (lambda (t) 
+                     (let* ([n (Poly-n t)]
+                            [syms (hash-table-get name-table t)])
+                       (list syms (Poly-body* syms t))))
+                   (list nps bp)))])))
+  
+  ;; unfold : Type -> Type
+  ;; must be applied to a Mu
+  (define (unfold t)
+    (match t
+      [(Mu: sc) (instantiate t sc)]
+      [_ (int-err "unfold: requires Mu type, got ~a" t)]))
+  
+  ;; type equality
+  (define type-equal? eq?)
+
+  ;; inequality - good
+  
+  (define (type<? s t)
+    (< (Type-seq s) (Type-seq t)))
+  
+  (define (type-compare s t)
+    (cond [(eq? s t) 0]
+          [(type<? s t) 1]
+          [else -1]))
+  
+  ;(trace subst subst-all)
+  
+  (provide
+   unfold
+   Mu-name: Poly-names:
+   Type-seq Effect-seq  
+   Mu-unsafe: Poly-unsafe:
+   Mu? Poly?
+   arr
+   Type? Effect?
+   Poly-n
+   free-vars*
+   type-equal? type-compare type<?
+   remove-dups
+   (rename-out [Mu:* Mu:]               
+               [Poly:* Poly:]
+               [Mu* make-Mu]
+               [Poly* make-Poly]
+               [Mu-body* Mu-body]
+               [Poly-body* Poly-body]))
+  
+  ;(trace unfold)
+  
+  
\ No newline at end of file
diff --git a/collects/typed-scheme/private/type-utils.ss b/collects/typed-scheme/private/type-utils.ss
new file mode 100644
index 0000000000..edfc6dc833
--- /dev/null
+++ b/collects/typed-scheme/private/type-utils.ss
@@ -0,0 +1,78 @@
+#lang scheme/base
+
+(require "type-rep.ss"
+         "effect-rep.ss"
+         "tc-utils.ss"
+         "rep-utils.ss"
+         "free-variance.ss"
+         mzlib/plt-match
+         (for-syntax scheme/base))
+
+(provide fv fv/list
+         substitute
+         subst-all
+         subst 
+         ret
+         instantiate-poly
+         tc-result: 
+         tc-result-equal? 
+         effects-equal?
+         tc-result-t)
+
+
+;; substitute : Type Name Type -> Type
+(define (substitute image name target)    
+  (define (sb t) (substitute image name t))
+  (if (hash-table-get (free-vars* target) name #f)
+      (type-case sb target
+                 [#:F name* (if (eq? name* name) image target)])
+      target))
+
+;; substitute many variables
+;; substitution = Listof[List[Name,Type]]
+;; subst-all : substition Type -> Type
+(define (subst-all s t)
+  (foldr (lambda (e acc) (substitute (cadr e) (car e) acc)) t s))
+
+
+
+
+(define (instantiate-poly t types)
+  (match t
+    [(Poly: ns body) 
+     (unless (= (length types) (length ns))
+       (int-err "instantiate-poly: wrong number of types: expected ~a, got ~a" (length ns) (length types)))
+     (subst-all (map list ns types) body)]
+    [_ (int-err "instantiate-many: requires Poly type, got ~a" t)]))
+
+
+;; this structure represents the result of typechecking an expression
+(define-struct tc-result (t thn els) #:inspector #f)
+
+(define-match-expander tc-result:
+  (lambda (stx)
+    (syntax-case stx ()
+      [(form pt) #'(struct tc-result (pt _ _))]
+      [(form pt pe1 pe2) #'(struct tc-result (pt pe1 pe2))])))
+
+;; convenience function for returning the result of typechecking an expression
+(define ret
+  (case-lambda [(t) (make-tc-result t (list) (list))]
+               [(t thn els) (make-tc-result t thn els)]))
+
+(define (subst v t e) (substitute t v e))
+
+
+;; type comparison
+
+;; equality - good
+
+(define tc-result-equal? equal?)
+(define (effects-equal? fs1 fs2) (andmap eq? fs1 fs2))
+
+
+;; fv : Type -> Listof[Name]
+(define (fv t) (hash-table-map (free-vars* t) (lambda (k v) k)))
+
+;; fv/list : Listof[Type] -> Listof[Name]
+(define (fv/list ts) (hash-table-map (combine-frees (map free-vars* ts)) (lambda (k v) k)))  
diff --git a/collects/typed-scheme/private/typechecker.ss b/collects/typed-scheme/private/typechecker.ss
new file mode 100644
index 0000000000..5b48745b83
--- /dev/null
+++ b/collects/typed-scheme/private/typechecker.ss
@@ -0,0 +1,16 @@
+#lang scheme/base
+
+(require "unit-utils.ss"
+         mzlib/trace
+         (only-in mzlib/unit provide-signature-elements)
+         "signatures.ss" #;"typechecker-unit.ss" "tc-toplevel.ss"
+         "tc-if-unit.ss" "tc-lambda-unit.ss" "tc-app-unit.ss"
+         "tc-let-unit.ss"
+         "tc-expr-unit.ss" "check-subforms-unit.ss")
+
+(provide-signature-elements typechecker^)
+
+(define-values/link-units/infer
+  ;typechecker@ 
+  tc-toplevel@
+  tc-if@ tc-lambda@ tc-app@ tc-let@ tc-expr@ check-subforms@)
diff --git a/collects/typed-scheme/private/unify.ss b/collects/typed-scheme/private/unify.ss
new file mode 100644
index 0000000000..71eeb582f0
--- /dev/null
+++ b/collects/typed-scheme/private/unify.ss
@@ -0,0 +1,106 @@
+#lang scheme/base
+
+(require "planet-requires.ss" 
+         "type-rep.ss"
+         "effect-rep.ss"
+         "type-comparison.ss"
+         "resolve-type.ss"
+         "type-utils.ss") 
+(require mzlib/plt-match         
+         mzlib/trace)
+
+(provide unify1)
+
+
+;; the types in the constraint list must be well-formed
+(define (unify cl) (unify/acc cl '()))
+
+(define (unify1 t1 t2) (unify (list (list t1 t2))))
+
+(define (unify/acc constraint-list acc)
+  (parameterize ([match-equality-test type-equal?])
+    (match constraint-list
+      ;; done!
+      [(list) acc]
+      ;; equal constraints can be discarded
+      [(list (list t t) rest ...) (unify/acc rest acc)]
+      ;; name resolution
+      [(list (list (Name: n) (Name: n*)) rest ...) 
+       (if (free-identifier=? n n*)
+           (unify/acc rest acc)
+           #f)]        
+      ;; type application
+      [(list (list (App: r args _) (App: r* args* _)) rest ...)
+       (unify/acc (append (map list (cons r args) (cons r* args*)) rest) acc)]
+      ;; unequal bound variables do not unify
+      [(list (list (B: _) (B: _)) rest ...) #f]
+      ;; unify a variable (skipping the occurs check for now)
+      [(list (list (F: v) t) rest ...) 
+       (unify/acc (map (lambda (p) (map (lambda (e) (subst v t e)) p)) rest) 
+                  (cons (list v t) acc))]
+      [(list (list t (F: v)) rest ...) 
+       (unify/acc (map (lambda (p) (map (lambda (e) (subst v t e)) p)) rest) 
+                  (cons (list v t) acc))]
+      ;; arrow types - just add a whole bunch of new constraints
+      [(list (list (Function: (list (arr: ts t t-rest t-thn-eff t-els-eff) ...)) 
+                   (Function: (list (arr: ss s s-rest s-thn-eff s-els-eff) ...)))
+             rest ...)
+       #;(printf "arrow unification~n")
+       (let ()
+         (define (compatible-rest t-rest s-rest)
+           (andmap (lambda (x y) (or (and x y) (and (not x) (not y)))) ;; either both #f or both not #f
+                   t-rest s-rest))
+         (define (flatten/zip x y) (map list (apply append x) (apply append y)))
+         (if (and (= (length ts) (length ss))
+                  (compatible-rest t-rest s-rest)
+                  (effects-equal? t-thn-eff s-thn-eff)
+                  (effects-equal? t-els-eff s-els-eff))
+             (let ([ret-constraints (map list t s)]
+                   ;; remove the #f's before adding to the constraints
+                   [rest-constraints (map list (filter values t-rest) (filter values s-rest))]
+                   ;; transform ((a b c) (d e)) ((1 2 3) (4 5)) into ((a 1) (b 2) (c 3) (d 4) (e 5))
+                   [arg-constraints (flatten/zip ts ss)])
+               #;(printf "constraints ~a~n"(append ret-constraints rest-constraints arg-constraints))
+               (unify/acc (append arg-constraints rest-constraints ret-constraints rest) acc))
+             (begin #;(printf "failure!~n") #f)))]
+      ;; aggregate types are simple
+      [(list (list (Vector: t) (Vector: s)) rest ...) (unify/acc (cons (list t s) rest) acc)]
+      [(list (list (Pair: t1 t2) (Pair: s1 s2)) rest ...) 
+       (unify/acc (list* (list t1 s1) (list t2 s2) rest) acc)]
+      [(list (list (Hashtable: t1 t2) (Hashtable: s1 s2)) rest ...) 
+       (unify/acc (list* (list t1 s1) (list t2 s2) rest) acc)]
+      [(list (list (Param: t1 t2) (Param: s1 s2)) rest ...) 
+       (unify/acc (list* (list t1 s1) (list t2 s2) rest) acc)]
+      ;; structs
+      [(list (list (Struct: nm p elems proc) (Struct: nm p elems* proc*)) rest ...)
+       (cond [(and proc proc*)
+              (unify/acc (append rest (map list elems elems*) (list (list proc proc*))) acc)]
+             [(or proc proc*) #f]
+             [else (unify/acc (append rest (map list elems elems*)) acc)])]
+      ;; union types - oh no!
+      [(list (list (Union: l1) (Union: l2)) rest ...)
+       (and (= (length l1) (length l2))
+            (unify/acc (append (map list l1 l2) rest) acc))]
+      [(list (or (list (Union: _) _) (list _ (Union: _))) rest ...) 
+       #;(printf "FIXME: union type ~n~a~n---------~n~a~n in unifier~n" 
+                 (caar constraint-list)
+                 (cadar constraint-list)) 
+       #f]
+      ;; mu types
+      [(list (list (Mu-unsafe: s) (Mu-unsafe: t)) rest ...) 
+       (unify/acc (cons (list s t) rest) acc)]
+      [(list (list t (? Mu? s)) rest ...) (unify/acc (cons (list t (unfold s)) rest) acc)]
+      [(list (list (? Mu? s) t) rest ...) (unify/acc (cons (list (unfold s) t) rest) acc)]
+      #;[((or (($ mu _ _) _) (_ ($ mu _ _))) rest ...) 
+         (printf "FIXME: mu types ~a in unifier~n" constraint-list)
+         #f]
+      ;; polymorphic types - don't do that
+      [(list (or (list _ (? Poly?)) (list _ (? Poly?))) rest ...)
+       ;(printf "FIXME: poly type in unifier~n")
+       #f]
+      ;; nothing else can have type variables
+      [else #f]
+      )))
+
+;(trace unify/acc)
+
diff --git a/collects/typed-scheme/private/union.ss b/collects/typed-scheme/private/union.ss
new file mode 100644
index 0000000000..a58d59fb75
--- /dev/null
+++ b/collects/typed-scheme/private/union.ss
@@ -0,0 +1,62 @@
+(module union mzscheme
+  
+  (require "type-rep.ss" "subtype.ss" "tc-utils.ss"
+           "type-effect-printer.ss" "rep-utils.ss"
+           "type-comparison.ss")
+  (require (lib "plt-match.ss") (lib "list.ss") (lib "trace.ss"))
+  
+  (provide Un #;(rename *Un Un))
+  
+  (define (make-union* set)
+    (match set
+      [(list t) t]
+      [_ (make-Union set)]))
+  
+  (define empty-union (make-Union null))
+  
+  (define (flat t) 
+    (match t
+      [(Union: es) es]
+      [_ (list t)]))    
+  #;(define (Values-types t) (match t [(Values: ts) ts]))
+  (define (remove-subtypes ts)
+    (let loop ([ts* ts] [result '()])
+      (cond [(null? ts*) (reverse result)]
+            [(ormap (lambda (t) (subtype (car ts*) t)) result) (loop (cdr ts*) result)]
+            [else (loop (cdr ts*) (cons (car ts*) result))])))
+  
+  (define Un
+    (case-lambda 
+      [() empty-union]
+      [args
+       ;; a is a Type (not a union type)
+       ;; b is a List[Type]
+       (define (union2 a b)     
+         (define b* (make-union* b))
+         (cond 
+           [(subtype a b*) (list b*)]
+           [(subtype b* a) (list a)]            
+           [else (cons a b)]))
+       #;(union-count!)    
+       (let ([types (remove-dups (sort (apply append (map flat args)) type<?))])
+         (cond
+           [(null? types) (make-union* null)]
+           [(null? (cdr types)) (car types)]           
+           [(ormap Values? types)
+            (if (andmap Values? types)
+                (make-Values (apply map Un (map Values-types types)))
+                (int-err "Un: should not take the union of multiple values with some other type: ~a" types))]
+           [else (make-union* #;(remove-subtypes types) (foldr union2 null types))]))]))
+  
+  #;(defintern (Un-intern args) (lambda (_ args) (apply Un args)) args)
+  
+  #;(define (*Un . args) (Un-intern args))
+  
+  ;(trace Un)
+  
+  (define (u-maker args) (apply Un args))
+  
+  ;(trace u-maker)
+  (set-union-maker! u-maker)
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/unit-utils.ss b/collects/typed-scheme/private/unit-utils.ss
new file mode 100644
index 0000000000..60b37a2a21
--- /dev/null
+++ b/collects/typed-scheme/private/unit-utils.ss
@@ -0,0 +1,93 @@
+(module unit-utils mzscheme
+  (require (lib "unit.ss"))
+  (require-for-syntax (lib "unit-exptime.ss")
+                      (lib "list.ss" "srfi" "1")
+                      (lib "match.ss"))
+  
+  (provide define-values/link-units/infer)
+
+  (define-syntax (define-values/link-units/infer stx)
+    ;; construct something we can put in the imports/exports clause from the datum
+    (define (datum->sig-elem d)
+      (if (car d)
+          (quasisyntax/loc (cdr d) (tag . #,(cdr d)))
+          (cdr d)))
+    
+    ;; identifier -> (list (listof imports) (listof exports))
+    (define (get-sigs id)
+      (define-values (imps exps) (unit-static-signatures id id))
+      (list imps exps))
+    
+    ;; flatten one level of a list
+    ;; listof[listof[a]] -> listof[a]
+    (define (flatten l) (apply append l))
+    
+    ;; returns two lists of sig-elems
+    (define (get-all-sigs ids)
+      (define imps/exps (map get-sigs ids))
+      (define-values (imps exps) (unzip2 imps/exps))
+      (values (flatten imps) (flatten exps)))
+    
+    ;; construct the runtime code
+    ;; takes 3 lists of identifiers and a syntax object for location info
+    (define (mk imports exports units stx)
+      (quasisyntax/loc stx
+        (begin (define-compound-unit/infer new-unit@ 
+                 (import #,@imports)
+                 (export #,@exports)
+                 (link #,@units))
+               (define-values/invoke-unit/infer new-unit@))))
+    
+    ;; compares two signature datums for equality
+    (define (sig=? sig1 sig2)
+      (and (eq? (car sig1) (car sig2))
+           (or (symbol? (car sig1)) (not (car sig1)))
+           (bound-identifier=? (cdr sig1) (cdr sig2))))
+    
+    ;; is imp in the list of exports?
+    (define (imp-in-exps? imp exps)
+      (s:member imp exps sig=?))
+    
+    ;; produce the imports not satisfied by the exports, and all the exports
+    ;; exports should not have duplicates
+    (define (imps/exps-from-units units)
+      (let-values ([(imps exps) (get-all-sigs units)])
+         (let* ([exps* (map datum->sig-elem exps)]
+                [imps* (map datum->sig-elem (filter (lambda (imp) (not (imp-in-exps? imp exps))) imps))])
+           (values imps* exps*))))
+    
+    (syntax-case stx (import export)
+      ;; here the exports are specified - they ought to be a subset of the allowable exports
+      [(_ (export . sigs) . units)
+       (let*-values ([(units) (syntax->list #'units)]
+                     [(imps exps) (imps/exps-from-units units)])
+         (mk imps (syntax->list #'sigs) units stx))]
+      ;; here we just export everything that's available
+      [(_ . units)
+       (andmap identifier? (syntax->list #'units))
+       (let*-values ([(units) (syntax->list #'units)]
+                     [(imps exps) (imps/exps-from-units units)])
+         (mk imps exps units stx))]))
+  
+    
+  ;; Tests
+  
+  (define-signature x^ (x))
+  (define-signature y^ (y))
+  (define-signature z^ (z))
+  
+  (define-unit y@
+    (import z^)
+    (export y^)
+    (define y (* 2 z)))
+  
+  (define-unit x@
+    (import y^)
+    (export x^)
+    (define (x) (+ y 1)))
+  
+  (define z 45)
+    
+  (define-values/link-units/infer (export x^) x@ y@)
+  
+  )
\ No newline at end of file
diff --git a/collects/typed-scheme/private/utils.ss b/collects/typed-scheme/private/utils.ss
new file mode 100644
index 0000000000..01a9317d61
--- /dev/null
+++ b/collects/typed-scheme/private/utils.ss
@@ -0,0 +1,121 @@
+#lang scheme/base
+
+(require (for-syntax scheme/base)
+         mzlib/plt-match
+         mzlib/struct)
+
+(provide with-syntax* syntax-map start-timing do-time reverse-begin define-simple-syntax printf/log
+         with-logging-to-file log-file-name ==
+         print-type*
+         print-effect*
+         define-struct/printer
+         id
+         filter-multiple)
+
+(define-syntax (with-syntax* stx)
+  (syntax-case stx ()
+    [(_ (cl) body ...) #'(with-syntax (cl) body ...)]
+    [(_ (cl cls ...) body ...)
+     #'(with-syntax (cl) (with-syntax* (cls ...) body ...))]
+    ))
+
+(define (filter-multiple l . fs)
+  (apply values
+         (map (lambda (f) (filter f l)) fs)))
+
+(define (syntax-map f stxl)
+  (map f (syntax->list stxl)))
+
+(define-syntax reverse-begin
+  (syntax-rules () [(_ h . forms) (begin0 (begin . forms) h)]))
+
+(define-syntax define-simple-syntax
+  (syntax-rules ()
+    [(dss (n . pattern) template)
+     (define-syntax n (syntax-rules () [(n . pattern) template]))]))
+
+(define log-file (make-parameter #f))
+(define-for-syntax logging? #f)
+
+(require (only-in (lib "file.ss") file-name-from-path))
+
+(define-syntax (printf/log stx)
+  (if logging?         
+      (syntax-case stx ()
+        [(_ fmt . args) 
+         #'(when (log-file)
+             (apply fprintf (log-file) (string-append "~a: " fmt) 
+                    (file-name-from-path (object-name (log-file)))
+                    args))])
+      #'(void)))
+
+(define (log-file-name src module-name)
+  (if (path? src)
+      (path-replace-suffix src ".log")
+      (format "~a.log" module-name)))
+
+(define-syntax (with-logging-to-file stx)
+  (syntax-case stx ()
+    [(_ file . body)
+     (if logging?
+         #'(parameterize ([log-file (open-output-file file 'truncate/replace)])
+             . body)
+         #'(begin . body))]))
+
+
+(define-for-syntax timing? #f)
+
+(define last-time (make-parameter #f))
+(define-syntaxes (start-timing do-time)
+  (if timing?        
+      (values
+       (syntax-rules ()
+         [(_ msg)
+          (begin
+            (when (last-time)
+              (error #f "Timing already started"))
+            (last-time (current-process-milliseconds))
+            (printf "Starting ~a at ~a~n" msg (last-time)))])
+       (syntax-rules ()
+         [(_ msg)
+          (begin
+            (unless (last-time)
+              (start-timing msg))
+            (let* ([t (current-process-milliseconds)]
+                   [old (last-time)]
+                   [diff (- t old)])
+              (last-time t)
+              (printf "Timing ~a at ~a@~a~n" msg diff t)))]))
+      (values (lambda _ #'(void)) (lambda _ #'(void)))))
+
+
+(define (symbol-append . args)
+  (string->symbol (apply string-append (map symbol->string args))))
+
+(define-match-expander
+  ==
+  (lambda (stx)
+    (syntax-case stx ()
+      [(_ val)
+       #'(? (lambda (x) (equal? val x)))])))
+
+(define-for-syntax printing? #t)
+
+(define print-type* (box (lambda _ (error "print-type* not yet defined"))))
+(define print-effect* (box (lambda _ (error "print-effect* not yet defined"))))
+
+(define-syntax (define-struct/printer stx)
+  (syntax-case stx ()
+    [(form name (flds ...) printer)
+     #`(define-struct/properties name (flds ...) 
+         #,(if printing? #'([prop:custom-write printer]) #'())
+         #f)]))
+
+(define (id kw . args)
+  (define (f v)
+    (cond [(string? v) v]
+          [(symbol? v) (symbol->string v)]
+          [(identifier? v) (symbol->string (syntax-e v))]))
+  (datum->syntax kw (string->symbol (apply string-append (map f args)))))
+
+
diff --git a/collects/typed-scheme/typed-reader.ss b/collects/typed-scheme/typed-reader.ss
new file mode 100644
index 0000000000..1bf7835585
--- /dev/null
+++ b/collects/typed-scheme/typed-reader.ss
@@ -0,0 +1,90 @@
+(module typed-reader mzscheme
+  (require (lib "etc.ss"))
+  
+  (require-for-template "private/prims.ss")  
+  
+  ;; Provides raise-read-error and raise-read-eof-error
+  (require (lib "readerr.ss" "syntax"))
+  
+  (define (skip-whitespace port)
+    ;; Skips whitespace characters, sensitive to the current
+    ;; readtable's definition of whitespace
+    (let ([ch (peek-char port)])
+      (unless (eof-object? ch)
+        ;; Consult current readtable:
+        (let-values ([(like-ch/sym proc dispatch-proc) 
+                      (readtable-mapping (current-readtable) ch)])
+          ;; If like-ch/sym is whitespace, then ch is whitespace
+          (when (and (char? like-ch/sym)
+                     (char-whitespace? like-ch/sym))
+            (read-char port)
+            (skip-whitespace port))))))
+  
+  (define (skip-comments read-one port src)
+    ;; Recursive read, but skip comments and detect EOF
+    (let loop ()
+      (let ([v (read-one)])
+        (cond
+          [(special-comment? v) (loop)]
+          [(eof-object? v)
+           (let-values ([(l c p) (port-next-location port)])
+             (raise-read-eof-error "unexpected EOF in type annotation" src l c p 1))]
+          [else v]))))
+
+  (define (parse port read-one src)    
+    (skip-whitespace port)
+    (let ([name (read-one)])
+      (begin0
+        (begin (skip-whitespace port)
+               (let ([next (read-one)])
+                 (case (syntax-e next)
+                   ;; type annotation
+                   [(:) (skip-whitespace port)
+                        (syntax-property name 'type-label (syntax-object->datum (read-one)))]
+                   [(::) (skip-whitespace port)
+                         (datum->syntax-object name `(ann ,name : ,(read-one)))]
+                   [(@) (let ([elems (let loop ([es '()])
+                                       (skip-whitespace port)
+                                       (if (equal? #\} (peek-char port))
+                                           (reverse es)
+                                           (loop (cons (read-one) es))))])
+                          (datum->syntax-object name `(inst ,name : ,@elems)))]
+                   ;; arbitrary property annotation
+                   [(PROP) (skip-whitespace port)
+                           (let* ([prop-name (syntax-e (read-one))])   
+                             (skip-whitespace port)
+                             (syntax-property name prop-name (read-one)))]
+                   ;; type annotation
+                   [else (syntax-property name 'type-label (syntax-object->datum next))])))
+        (skip-whitespace port)
+        (let ([c (read-char port)])
+          #;(printf "char: ~a" c)
+          (unless (equal? #\} c)
+            (let-values ([(l c p) (port-next-location port)])
+              (raise-read-error (format "typed expression ~a not properly terminated" (syntax-object->datum name)) src l c p 1)))))))
+  
+  (define parse-id-type
+    (case-lambda
+      [(ch port src line col pos)
+       ;; `read-syntax' mode
+       (datum->syntax-object
+        #f
+        (parse port 
+                     (lambda () (read-syntax src port ))
+                     src)
+        (let-values ([(l c p) (port-next-location port)])
+          (list src line col pos (and pos (- p pos)))))]))
+
+  (define readtable
+    (make-readtable #f #\{ 'dispatch-macro parse-id-type))
+  
+  (define (*read inp)
+    (parameterize ([current-readtable readtable])
+      (read inp)))
+  
+  (define (*read-syntax src port)
+    (parameterize ([current-readtable readtable])
+      (read-syntax src port)))
+  
+  (provide (rename *read read) (rename *read-syntax read-syntax))
+  )
diff --git a/collects/typed-scheme/typed-scheme.scrbl b/collects/typed-scheme/typed-scheme.scrbl
new file mode 100644
index 0000000000..c534db2bb3
--- /dev/null
+++ b/collects/typed-scheme/typed-scheme.scrbl
@@ -0,0 +1,392 @@
+#lang scribble/doc
+
+@begin[(require scribble/manual)
+       (require (for-label typed-scheme/lang/main))]
+
+@begin[
+(define (item* header . args) (apply item @bold[header]{: } args))
+(define-syntax-rule (tmod forms ...) (schememod typed-scheme forms ...))
+]
+
+@title[#:tag "top"]{@bold{Typed Scheme}: Scheme with Static Types}
+
+@(defmodulelang typed-scheme #:use-sources (typed-scheme/lang/main))
+
+Typed Scheme is a Scheme-like language, with a type system that
+supports common Scheme programming idioms.  Explicit type declarations
+are required --- that is, there is no type inference.  The language
+supports a number of features from previous work on type systems that
+make it easier to type Scheme programs, as well as a novel idea dubbed
+@italic{occurrence typing} for case discrimination.
+
+Typed Scheme is also designed to integrate with the rest of your PLT
+Scheme system.  It is possible to convert a single module to Typed
+Scheme, while leaving the rest of the program unchanged.  The typed
+module is protected from the untyped code base via
+automatically-synthesized contracts.
+
+Further information on Typed Scheme is available from
+@link["http://www.ccs.neu.edu/home/samth/typed-scheme"]{the homepage}.
+
+@section{Starting with Typed Scheme}
+
+If you already know PLT Scheme, or even some other Scheme, it should be
+easy to start using Typed Scheme.
+
+@subsection{A First Function}
+
+The following program defines the Fibonacci function in PLT Scheme:
+
+@schememod[scheme
+(define (fib n)
+  (cond [(= 0 n) 1]
+	[(= 1 n) 1]
+	[else (+ (fib (- n 1)) (fib (- n 2)))]))
+]
+
+This program defines the same program using Typed Scheme.
+ 
+@schememod[typed-scheme
+(: fib (Number -> Number))
+(define (fib n)
+  (cond [(= 0 n) 1]
+        [(= 1 n) 1]
+        [else (+ (fib (- n 1)) (fib (- n 2)))]))
+]
+
+There are two differences between these programs:
+
+@itemize{
+  @item*[@elem{The Language}]{@schememodname[scheme] has been replaced by @schememodname[typed-scheme].}
+
+  @item*[@elem{The Type Annotation}]{We have added a type annotation
+for the @scheme[fib] function, using the @scheme[:] form.}  }
+
+In general, these are most of the changes that have to be made to a
+PLT Scheme program to transform it into a Typed Scheme program.
+@margin-note{Changes to uses of @scheme[require] may also be necessary
+- these are described later.}
+
+@subsection[#:tag "complex"]{Adding more complexity}
+
+Other typed binding forms are also available.  For example, we could have
+rewritten our fibonacci program as follows:
+
+@schememod[typed-scheme
+(: fib (Number -> Number))
+(define (fib n)
+  (let ([base? (or (= 0 n) (= 1 n))])
+    (if base? 1
+        (+ (fib (- n 1)) (fib (- n 2))))))
+]
+
+This program uses the @scheme[let] binding form, but no new type
+annotations are required.  Typed Scheme infers the type of
+@scheme[base?].  
+
+We can also define mutually-recursive functions:
+
+@schememod[typed-scheme
+(: my-odd? (Number -> Boolean))
+(define (my-odd? n)
+  (if (= 0 n) #f
+      (my-even? (- n 1))))
+
+(: my-even? (Number -> Boolean))
+(define (my-even? n)
+  (if (= 0 n) #t
+      (my-odd? (- n 1))))
+
+(display (my-even? 12))
+]
+
+As expected, this program prints @schemeresult[#t].
+
+
+@subsection{Defining New Datatypes}
+
+If our program requires anything more than atomic data, we must define
+new datatypes.  In Typed Scheme, structures can be defined, similarly
+to PLT Scheme structures.  The following program defines a date
+structure and a function that formats a date as a string, using PLT
+Scheme's built-in @scheme[format] function.
+
+@schememod[typed-scheme
+(define-typed-struct Date ([day : Number] [month : String] [year : Number]))
+
+(: format-date (Date -> String))
+(define (format-date d)
+  (format "Today is day ~a of ~a in the year ~a" 
+          (Date-day d) (Date-month d) (Date-year d)))
+
+(display (format-date (make-Date 28 "November" 2006)))
+]
+
+Here we see the new built-in type @scheme[String] as well as a definition
+of the new user-defined type @scheme[my-date].  To define
+@scheme[my-date], we provide all the information usually found in a
+@scheme[define-struct], but added type annotations to the fields using
+the @scheme[define-typed-struct] form.
+Then we can use the functions that this declaration creates, just as
+we would have with @scheme[define-struct].
+
+
+@subsection{Recursive Datatypes and Unions}
+
+Many data structures involve multiple variants.  In Typed Scheme, we
+represent these using @italic{union types}, written @scheme[(U t1 t2 ...)].
+
+@schememod[typed-scheme
+(define-type-alias Tree (U leaf node))
+(define-typed-struct leaf ([val : Number]))
+(define-typed-struct node ([left : Tree] [right : Tree]))
+
+(: tree-height (Tree -> Number))
+(define (tree-height t)
+  (cond [(leaf? t) 1]
+        [else (max (tree-height (node-left t))
+                   (tree-height (node-right t)))]))
+
+(: tree-sum (Tree -> Number))
+(define (tree-sum t)
+  (cond [(leaf? t) (leaf-val t)]
+        [else (+ (tree-sum (node-left t))
+                 (tree-sum (node-right t)))]))
+]
+
+In this module, we have defined two new datatypes: @scheme[leaf] and
+@scheme[node].  We've also defined the type alias @scheme[Tree] to be
+@scheme[(U node leaf)], which represents a binary tree of numbers.  In
+essence, we are saying that the @scheme[tree-height] function accepts
+a @scheme[Tree], which is either a @scheme[node] or a @scheme[leaf],
+and produces a number.
+
+In order to calculate interesting facts about trees, we have to take
+them apart and get at their contents.  But since accessors such as
+@scheme[node-left] require a @scheme[node] as input, not a
+@scheme[Tree], we have to determine which kind of input we
+were passed.  
+
+For this purpose, we use the predicates that come with each defined
+structure.  For example, the @scheme[leaf?] predicate distinguishes
+@scheme[leaf]s from all other Typed Scheme values.  Therefore, in the
+first branch of the @scheme[cond] clause in @scheme[tree-sum], we know
+that @scheme[t] is a @scheme[leaf], and therefore we can get its value
+with the @scheme[leaf-val] function.
+
+In the else clauses of both functions, we know that @scheme[t] is not
+a @scheme[leaf], and since the type of @scheme[t] was @scheme[Tree] by
+process of elimination we can determine that @scheme[t] must be a
+@scheme[node].  Therefore, we can use accessors such as
+@scheme[node-left] and @scheme[node-right] with @scheme[t] as input.
+
+@section{Polymorphism}
+
+Virtually every Scheme program uses lists and sexpressions.  Fortunately, Typed
+Scheme can handle these as well.  A simple list processing program can be
+written like this:
+
+@schememod[typed-scheme
+(: sum-list ((Listof Number) -> Number))
+(define (sum-list l)
+  (cond [(null? l) 0]
+        [else (+ (car l) (sum-list (cdr l)))]))
+]
+
+This looks similar to our earlier programs --- except for the type
+of @scheme[l], which looks like a function application.  In fact, it's
+a use of the @italic{type constructor} @scheme[Listof], which takes
+another type as its input, here @scheme[Number].  We can use
+@scheme[Listof] to construct the type of any kind of list we might
+want.  
+
+We can define our own type constructors as well.  For example, here is
+an analog of the @tt{Maybe} type constructor from Haskell:
+
+@schememod[typed-scheme
+(define-typed-struct Nothing ())
+(define-typed-struct (a) Just ([v : a]))
+
+(define-type-alias (Maybe a) (U Nothing (Just a)))
+
+(: find (Number (Listof Number) -> (Maybe Number)))
+(define (find v l)
+  (cond [(null? l) (make-Nothing)]
+        [(= v (car l)) (make-Just v)]
+        [else (find v (cdr l))]))
+]
+
+The first @scheme[define-typed-struct] defines @scheme[Nothing] to be
+a structure with no contents.  
+
+The second definition
+
+@schemeblock[
+(define-typed-struct (a) Just ([v : a]))
+]
+
+creates a parameterized type, @scheme[Just], which is a structure with
+one element, whose type is that of the type argument to
+@scheme[Just].  Here the type parameters (only one, @scheme[a], in
+this case) are written before the type name, and can be referred to in
+the types of the fields.
+
+The type alias definiton
+@schemeblock[
+  (define-type-alias (Maybe a) (U Nothing (Just a)))
+]
+creates a parameterized alias --- @scheme[Maybe] is a potential
+container for whatever type is supplied.
+
+The @scheme[find] function takes a number @scheme[v] and list, and
+produces @scheme[(make-Just v)] when the number is found in the list,
+and @scheme[(make-Nothing)] otherwise.  Therefore, it produces a
+@scheme[(Maybe Number)], just as the annotation specified.  
+
+@section[#:tag "type-ref"]{Type Reference}
+
+@subsubsub*section{Base Types}
+These types represent primitive Scheme data.
+@defidform[Number]{Any number}
+@defidform[Boolean]{Either @scheme[#t] or @scheme[#f]}
+@defidform[String]{A string}
+@defidform[Keyword]{A PLT Scheme literal keyword}
+@defidform[Symbol]{A symbol}
+@defidform[Any]{Any value}
+
+@subsubsub*section{Type Constructors}
+The following constructors are parameteric in their type arguments.
+
+@defform[(Listof t)]{Homogenous lists of @scheme[t]}
+@defform[(Vectorof t)]{Homogenous vectors of @scheme[t]}
+@defform[(Option t)]{Either @scheme[t] of @scheme[#f]}
+
+@;{
+@schemeblock[
+(define: f : (Number -> Number) (lambda: ([x : Number]) 3))
+]
+}
+
+@begin[
+(require (for-syntax scheme/base))
+(define-syntax (definfixform stx)
+  (syntax-case stx ()
+    [(_ dummy . rest) #'(begin (specform . rest))]))
+#;
+(define-syntax (definfixform stx)
+  (syntax-case stx ()
+    [(_ id spec desc ...)
+     #'(*defforms (quote-syntax id) 
+		  '()
+		  '(spec) 
+		  (list (lambda (x) (schemeblock0 spec)))
+		  '()
+		  '()
+		  (lambda () (list desc ...)))]))
+]
+
+@defform[(Pair s t)]{is the pair containing @scheme[s] as the @scheme[car]
+  and @scheme[t] as the @scheme[cdr]}
+@defform[(-> dom ... rng)]{is the type of functions from the (possibly-empty)
+  sequence @scheme[dom ...] to the @scheme[rng] type.}
+@defform[(U t ...)]{is the union of the types @scheme[t ...]}
+@defform[(case-lambda fun-ty ...)]{is a function that behaves like all of
+  the @scheme[fun-ty]s.  The @scheme[fun-ty]s must all be function
+  types constructed with @scheme[->].}
+@defform/none[(t t1 t2 ...)]{is the instantiation of the parametric type
+  @scheme[t] at types @scheme[t1 t2 ...]}
+@defform[(All (v ...) t)]{is a parameterization of type @scheme[t], with
+  type variables @scheme[v ...]}
+@defform[(values t ...)]{is the type of a sequence of multiple values, with
+types @scheme[t ...].  This can only appear as the return type of a
+function.}
+@defform/none[v]{where @scheme[v] is a number, boolean or string, is the singleton type containing
+only that value}
+@defform/none[i]{where @scheme[i] is an identifier can be a reference to a type
+name or a type variable}
+@defform[(Rec n t)]{is a recursive type where @scheme[n] is bound to the
+recursive type in the body @scheme[t]}
+
+Other types cannot be written by the programmer, but are used
+internally and may appear in error messages.
+
+@defform/none[(struct:n (t ...))]{is the type of structures named
+@scheme[n] with field types @scheme[t].  There may be multiple such
+types with the same printed representation.}
+@defform/none[<n>]{is the printed representation of a reference to the
+type variable @scheme[n]}
+
+@section[#:tag "special-forms"]{Special Form Reference}
+
+Typed Scheme provides a variety of special forms above and beyond
+those in PLT Scheme.  They are used for annotating variables with types,
+creating new types, and annotating expressions.
+
+@subsection{Binding Forms}
+
+@scheme[_loop], @scheme[_f], @scheme[_a], and @scheme[_v] are names, @scheme[_t] is a type.
+ @scheme[_e] is an expression and @scheme[_body] is a block.
+
+@defform*[[(define: (f [v : t] ...) : t body)
+	   (define: v : t e)]]{}
+@defform[
+  (pdefine: (a ...) (f [v : t] ...) : t body)]{}
+
+@defform*[[
+  (let: ([v : t e] ...) body)
+  (let: loop : t0 ([v : t e] ...) body)]]{where @scheme[_t0] is the type of the
+  result of @scheme[_loop] (and thus the result of the entire expression).}
+@defform[
+  (letrec: ([v : t e] ...) body)]{}
+@defform[
+  (let*: ([v : t e] ...) body)]{}
+@defform*[[
+  (lambda: ([v : t] ...) body)
+  (lambda: ([v : t] ... . [v : t]) body)]]{}
+@defform*[[
+  (plambda: (a ...) ([v : t] ...) body)
+  (plambda: (a ...) ([v : t] ... . [v : t]) body)]]{}
+@defform[
+  (case-lambda: [formals body] ...)]{where @scheme[_formals] is like
+  the second element of a @scheme[lambda:]}
+@defform[
+  (pcase-lambda: (a ...) [formals body] ...)]{where @scheme[_formals] is like
+  the third element of a @scheme[plambda:]}
+
+
+@subsection{Structure Definitions}
+@defform*[[
+(define-typed-struct name ([f : t] ...))
+(define-typed-struct (name parent) ([f : t] ...))
+(define-typed-struct (v ...) name ([f : t] ...))
+(define-typed-struct (v ...) (name parent) ([f : t] ...))]]
+
+@subsection{Type Aliases}
+@defform*[[(define-type-alias name t)
+	   (define-type-alias (name v ...) t)]]{}
+
+
+@subsection{Type Annotation}
+
+@defform[
+(: v t)
+]
+
+@litchar{#{v : t}} This is legal only for binding occurences of @scheme[_v].
+
+@litchar{#{e :: t}} This is legal only in expression contexts.
+
+
+@subsection{Require}
+
+Here, @scheme[_m] is a module spec, @scheme[_pred] is an identifier
+naming a predicate, and @scheme[_r] is an optionally-renamed identifier.
+
+@defform*[[
+(require/typed r t m)
+(require/typed m [r t] ...)
+]]{}
+
+@defform[(require/opaque-type t pred m)]{}
+
+@defform[(require-typed-struct name ([f : t] ...) m)]{}
diff --git a/collects/typed-scheme/typed-scheme.ss b/collects/typed-scheme/typed-scheme.ss
new file mode 100644
index 0000000000..4a85636203
--- /dev/null
+++ b/collects/typed-scheme/typed-scheme.ss
@@ -0,0 +1,150 @@
+#lang scheme/base
+
+(require "private/prims.ss" 
+         "private/init-envs.ss"
+         "private/extra-procs.ss"
+         "private/internal-forms.ss"
+         "private/base-env.ss"
+         (for-syntax 
+          scheme/base
+          "private/type-utils.ss"
+          "private/typechecker.ss" 
+          "private/type-rep.ss"
+          "private/provide-handling.ss"
+          "private/type-environments.ss" "private/tc-utils.ss"
+          "private/type-env.ss" "private/type-name-env.ss"
+          "private/type-alias-env.ss"
+          "private/utils.ss"
+          "private/internal-forms.ss"
+          "private/init-envs.ss"
+          "private/type-effect-convenience.ss"
+          "private/effect-rep.ss"
+          "private/rep-utils.ss"
+          "private/type-contract.ss"
+          "private/nest.ss"
+          syntax/kerncase
+          mzlib/list
+          mzlib/plt-match))
+
+
+(provide 
+ ;; provides syntax such as define: and define-typed-struct
+ (all-from-out "private/prims.ss")
+ ;; provides some pointless procedures - should be removed
+ (all-from-out "private/extra-procs.ss"))
+
+(provide-tnames)
+(provide-extra-tnames)
+
+
+(provide (rename-out [module-begin #%module-begin]
+                     [with-handlers: with-handlers]
+                     [top-interaction #%top-interaction]
+                     [#%plain-lambda lambda]
+                     [#%plain-app #%app]
+                     [require require]))
+
+(define-for-syntax catch-errors? #f)
+
+
+(define-syntax (module-begin stx)
+  (define module-name (syntax-property stx 'enclosing-module-name))
+  ;(printf "BEGIN: ~a~n" (syntax->datum stx))
+  (with-logging-to-file 
+   (log-file-name (syntax-src stx) module-name)
+   (syntax-case stx ()
+     [(mb forms ...)
+      (nest
+          ([begin (set-box! typed-context? #t)
+                  (start-timing module-name)]
+           [with-handlers
+               ([(lambda (e) (and catch-errors? (exn:fail? e) (not (exn:fail:syntax? e))))
+                 (lambda (e) (tc-error "Internal error: ~a" e))])]
+           [parameterize (;; this parameter is for parsing types
+                          [current-tvars initial-tvar-env]
+                          ;; this parameter is just for printing types
+                          ;; this is a parameter to avoid dependency issues
+                          [current-type-names
+                           (lambda ()
+                             (append 
+                              (type-name-env-map (lambda (id ty)
+                                                   (cons (syntax-e id) ty)))
+                              (type-alias-env-map (lambda (id ty)
+                                                    (cons (syntax-e id) ty)))))]
+                          ;; reinitialize seen type variables
+                          [type-name-references null])]
+           [begin (do-time "Initialized Envs")]
+           ;; local-expand the module
+           ;; pmb = #%plain-module-begin                            
+           [with-syntax ([new-mod 
+                          (local-expand #`(#%plain-module-begin 
+                                           forms ...)
+                                        'module-begin 
+                                        null
+                                        #;stop-list)])]
+           [with-syntax ([(pmb body2 ...) #'new-mod])]
+           [begin (do-time "Local Expand Done")]
+           [with-syntax ([after-code (parameterize ([orig-module-stx stx]
+                                                    [expanded-module-stx #'new-mod])
+                                       (type-check #'(body2 ...)))]
+                         [check-syntax-help (syntax-property #'(void) 'disappeared-use (type-name-references))]
+                         [(transformed-body ...) (remove-provides #'(body2 ...))])]
+           [with-syntax ([(transformed-body ...) (change-contract-fixups #'(transformed-body ...))])])
+        (do-time "Typechecked")
+        (printf "checked ~a~n" module-name)
+        #;(printf "created ~a types~n" (count!))
+        #;(printf "tried to create ~a types~n" (all-count!))
+        #;(printf "created ~a union types~n" (union-count!))
+        ;; reconstruct the module with the extra code
+        #'(#%module-begin transformed-body ... after-code check-syntax-help))])))
+
+(define-syntax (top-interaction stx)
+  (syntax-case stx ()
+    [(_ . (module . rest))
+     (eq? 'module (syntax-e #'module))
+     #'(module . rest)]
+    [(_ . form)     
+     (nest
+         ([begin (set-box! typed-context? #t)]
+          [parameterize (;; this paramter is for parsing types
+                         [current-tvars initial-tvar-env]
+                         ;; this parameter is just for printing types
+                         ;; this is a parameter to avoid dependency issues
+                         [current-type-names
+                          (lambda () 
+                            (append 
+                             (type-name-env-map (lambda (id ty)
+                                                  (cons (syntax-e id) ty)))
+                             (type-alias-env-map (lambda (id ty)
+                                                   (cons (syntax-e id) ty)))))])]
+         ;(do-time "Initialized Envs")
+          ;; local-expand the module
+          [let ([body2 (local-expand #'(#%top-interaction . form) 'top-level null)])]
+          [parameterize ([orig-module-stx #'form]
+                         [expanded-module-stx body2])]
+          ;; typecheck the body, and produce syntax-time code that registers types
+          [let ([type (tc-toplevel-form body2)])])
+       (kernel-syntax-case body2 #f
+         [(head . _)
+          (or (free-identifier=? #'head #'define-values)
+              (free-identifier=? #'head #'define-syntaxes)
+              (free-identifier=? #'head #'require)
+              (free-identifier=? #'head #'provide)
+              (free-identifier=? #'head #'begin)
+              (type-equal? -Void (tc-result-t type)))
+          body2]
+         ;; construct code to print the type
+         [_           
+          (nest
+              ([with-syntax ([b body2]
+                             [ty-str (match type
+                                       [(tc-result: t)
+                                        (format "- : ~a\n" t)]
+                                       [x (int-err "bad type result: ~a" x)])])])
+            #`(let ([v b] [type 'ty-str])
+                (begin0 
+                  v
+                  (printf type))))]))]))
+
+
+