Contract fixes.

original commit: c739128703d917540ff963775459b6c75ccf2c80

collects/typed-scheme/typecheck/tc-envops.rkt

@@ -72,7 +72,8 @@
 
 ;; sets the flag box to #f if anything becomes (U)
 (d/c (env+ env fs flag)
-  (env? (listof Filter/c) (box/c #t). -> . env?)
+  (([e env?] [fs (listof Filter/c)] [bx (box/c boolean?)])
+   #:pre (bx) (unbox bx) . ->i . [_ env?])
   (define-values (props atoms) (combine-props fs (env-props env) flag))
   (for/fold ([Γ (replace-props env (append atoms props))]) ([f atoms])
     (match f
@@ -85,4 +86,5 @@
                             x Γ)]
       [_ Γ])))
 
-(p/c [env+ (env? (listof Filter/c) (box/c #t). -> . env?)])
+(p/c [env+ (([e env?] [fs (listof Filter/c)] [bx (box/c boolean?)])
+	    #:pre (bx) (unbox bx) . ->i . [_ env?])])

collects/typed-scheme/types/substitute.rkt

@@ -12,13 +12,6 @@
          (struct-out t-subst) (struct-out i-subst) (struct-out i-subst/starred) (struct-out i-subst/dotted)
          substitution/c make-simple-substitution)
 
-(define (subst v t e) (substitute t v e))
-
-(d/c (make-simple-substitution vs ts)
-  (([vs (listof symbol?)] [ts (listof Type/c)]) () #:pre-cond (= (length vs) (length ts)) . ->d . [_ substitution/c])
-  (for/hash ([v (in-list vs)] [t (in-list ts)])
-    (values v (t-subst t))))
-
 (d-s/c subst-rhs () #:transparent)
 (d-s/c (t-subst subst-rhs) ([type Type/c]) #:transparent)
 (d-s/c (i-subst subst-rhs) ([types (listof Type/c)]) #:transparent)
@@ -27,6 +20,16 @@
 
 (define substitution/c (hash/c symbol? subst-rhs? #:immutable #t))
 
+(define (subst v t e) (substitute t v e))
+
+(d/c (make-simple-substitution vs ts)
+  (([vs (listof symbol?)] [ts (listof Type/c)]) ()
+   #:pre (vs ts) (= (length vs) (length ts))
+    . ->i . [_ substitution/c])
+  (for/hash ([v (in-list vs)] [t (in-list ts)])
+    (values v (t-subst t))))
+
+
 ;; substitute : Type Name Type -> Type
 (d/c (substitute image name target #:Un [Un (get-union-maker)])
   ((Type/c symbol? Type?) (#:Un procedure?) . ->* . Type?)