Hide implementation details of type contexts

Author: iitalics

hackett-lib/hackett/private/base.rkt

@@ -241,9 +241,7 @@
       #:literal-sets [type-literals]
       [(#%type:wobbly-var x^)
        #:with [x1^ x2^] (generate-temporaries #'[x^ x^])
-       (modify-type-context
-        #{snoc % (ctx:solution #'x^ (template
-                                     (?->* (#%type:wobbly-var x1^) (#%type:wobbly-var x2^))))})
+       (type-inst-l! #'x^ (template (?->* (#%type:wobbly-var x1^) (#%type:wobbly-var x2^))))
        (values (quasisyntax/loc src
                  (lazy- (#%app- (force- #,e_fn) #,(τ⇐! e_arg #'(#%type:wobbly-var x1^)))))
                #'(#%type:wobbly-var x2^))]

hackett-lib/hackett/private/typecheck.rkt

@@ -31,11 +31,9 @@
          hackett/private/util/list
          hackett/private/util/stx)
 
-(provide (contract-out [struct ctx:solution ([x^ identifier?] [t type?])])
-         type? type=? constr? type-mono? type-vars^ type->string
+(provide type? type=? constr? type-mono? type-vars^ type->string
          generalize inst insts type<:/full! type<:/elaborate! type<:! type-inst-l! type-inst-r!
-         ctx-elem? ctx? ctx-elem=? ctx-member? ctx-remove
-         ctx-find-solution current-ctx-solution apply-subst apply-current-subst
+         apply-subst apply-current-subst
          current-type-context modify-type-context
          attach-type attach-expected get-type get-expected apply-current-subst-in-tooltips
          make-typed-var-transformer
@@ -155,11 +153,9 @@
 
 (define/contract (ctx-find-solution ctx x^)
   (-> ctx? identifier? (or/c type? #f))
-  (and~> (findf #{and (ctx:solution? %) (free-identifier=? x^ (ctx:solution-x^ %))} ctx)
+  (and~> (findf #{and (ctx:solution? %)
+                      (free-identifier=? x^ (ctx:solution-x^ %))} ctx)
          ctx:solution-t))
-(define/contract (current-ctx-solution x^)
-  (-> identifier? (or/c type? #f))
-  (ctx-find-solution (current-type-context) x^))
 
 (define/contract (apply-subst ctx t)
   (-> ctx? type? type?)

hackett-lib/hackett/private/typeclass.rkt

@@ -273,7 +273,7 @@
      #t]
     [[(#%type:wobbly-var x^) t]
      #:when (type-mono? #'t)
-     (modify-type-context #{snoc % (ctx:solution #'x^ #'t)})
+     (type-inst-l! #'x^ #'t)
      #t]
     [[(#%type:con a) (#%type:con b)]
      #:when (free-identifier=? #'a #'b)