Add a case-> type-constructor as a synonym for case-lambda.

original commit: 1b3052748e3278deefabf646f4990dc1f8064202

collects/tests/typed-scheme/unit-tests/parse-type-tests.rkt

@@ -98,6 +98,8 @@
     (-polydots (a) (t:-> (make-ValuesDots (list) a 'a)))]
    [(case-lambda (Number -> Boolean) (Number Number -> Number)) (cl-> [(N) B]
                                                                       [(N N) N])]
+   [(case-> (Number -> Boolean) (Number Number -> Number)) (cl-> [(N) B]
+                                                                 [(N N) N])]
    [1 (-val 1)]
    [#t (-val #t)]
    [#f (-val #f)]

collects/typed-scheme/private/base-types-extra.rkt

@@ -12,7 +12,7 @@
 
 ;; special type names that are not bound to particular types
 (define-other-types
-  -> U Rec All Opaque Vector
+  -> case-> U Rec All Opaque Vector
   Parameterof List List* Class Values Instance Refinement
   pred)
 

collects/typed-scheme/private/parse-type.rkt

@@ -152,7 +152,7 @@
   (parameterize ([current-orig-stx stx])    
     (syntax-parse
         stx
-      #:literals (t:Class t:Refinement t:Instance t:List t:List* cons t:pred t:-> : case-lambda
+      #:literals (t:Class t:Refinement t:Instance t:List t:List* cons t:pred t:-> : case-lambda t:case->
                           t:Rec t:U t:All t:Opaque t:Parameter t:Vector quote)
       [t
        #:declare t (3d Type?)
@@ -202,7 +202,7 @@
       [((~and kw t:pred) t) 
        (add-type-name-reference #'kw)
        (make-pred-ty (parse-type #'t))]     
-      [((~and kw case-lambda) tys ...)
+      [((~and kw (~or case-lambda t:case->)) tys ...)
        (add-type-name-reference #'kw)
        (make-Function 
         (for/list ([ty (syntax->list #'(tys ...))])

collects/typed-scheme/private/prims.rkt

@@ -30,7 +30,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
 (require "../utils/require-contract.rkt"
          "colon.rkt"
          "../typecheck/internal-forms.rkt"
-         (rename-in racket/contract [-> c->])
+         (rename-in racket/contract [-> c->] [case-> c:case->])
          "base-types.rkt"
          "base-types-extra.rkt"
          racket/flonum ; for for/flvector and for*/flvector