Remove top-arr.

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt

@@ -665,10 +665,6 @@
           ;; parameters are just like one-arg functions
           [((Param: in1 out1) (Param: in2 out2))
            (% cset-meet (cg in2 in1) (cg out1 out2))]
-          ;; every function is trivially below top-arr
-          [((Function: _)
-            (Function: (list (top-arr:))))
-           empty]
           [((Function: (list s-arr ...))
             (Function: (list t-arr ...)))
            (% cset-meet*

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/promote-demote.rkt

@@ -37,12 +37,16 @@
     (define (contra t) (structural-recur t 'contra))
 
     (match T
-      [(? structural?) (structural-map T structural-recur)]
       [(F: name) (if (memq name V) (if change Univ -Bottom) T)]
+      [(Function: arrs)
+       (make-Function
+         (filter values
+           (for/list ([arr (in-list arrs)])
+             (match arr
               [(arr: dom rng rest drest kws)
                (cond
                  [(apply V-in? V (get-filters rng))
-          (make-top-arr)]
+                  #f]
                  [(and drest (memq (cdr drest) V))
                   (make-arr (map contra dom)
                             (co rng)
@@ -54,7 +58,8 @@
                             (co rng)
                             (and rest (contra rest))
                             (and drest (cons (contra (car drest)) (cdr drest)))
-                    (map contra kws))])]
+                            (map contra kws))])]))))]
+      [(? structural?) (structural-map T structural-recur)]
       [(? Filter?) ((sub-f co) T)]
       [(? Object?) ((sub-o co) T)]
       [(? Type?) ((sub-t co) T)]))

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/private/type-contract.rkt

@@ -475,7 +475,6 @@
   (define (t->sc/neg t #:recursive-values (recursive-values recursive-values))
     (loop t (flip-side typed-side) recursive-values))
   (match f
-    [(Function: (list (top-arr:))) (case->/sc empty)]
     [(Function: arrs)
      ;; Try to generate a single `->*' contract if possible.
      ;; This allows contracts to be generated for functions with both optional and keyword args.
@@ -545,16 +544,13 @@
        (define arities
          (for/list ([t arrs])
            (match t
-             [(arr: dom _ _ _ _) (length dom)]
+             [(arr: dom _ _ _ _) (length dom)])))
-             ;; is there something more sensible here?
-             [(top-arr:) (int-err "got top-arr")])))
        (define maybe-dup (check-duplicate arities))
        (when maybe-dup
          (fail #:reason (~a "function type has two cases of arity " maybe-dup)))
        (if (= (length arrs) 1)
            ((f #f) (first arrs))
-           (case->/sc (map (f #t) arrs)))])]
+           (case->/sc (map (f #t) arrs)))])]))
-    [_ (int-err "not a function" f)]))
 
 (module predicates racket/base
   (require racket/extflonum)

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/type-rep.rkt

@@ -347,13 +347,8 @@
                     (and drest (cons (type-rec-id (car drest)) (cdr drest)))
                     (map type-rec-id kws))])
 
-;; top-arr is the supertype of all function types
-(def-type top-arr () [#:fold-rhs #:base])
-
-(define arr/c (or/c top-arr? arr?))
-
 ;; arities : Listof[arr]
-(def-type Function ([arities (listof arr/c)])
+(def-type Function ([arities (listof arr?)])
   [#:key 'procedure]
   [#:frees (λ (f) (combine-frees (map f arities)))]
   [#:fold-rhs (*Function (map type-rec-id arities))])

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/check-class-unit.rkt

@@ -1366,10 +1366,7 @@
   (match type
     [(Function: (list arrs ...))
      (define fixed-arrs
-       (for/list ([arr arrs]
+       (for/list ([arr arrs])
-                  ;; ignore top-arr, since the arity cannot
-                  ;; be sensibly modified in that case
-                  #:when (arr? arr))
          (match-define (arr: doms rng rest drest kws) arr)
          (make-arr (cons self-type doms) rng rest drest kws)))
      (make-Function fixed-arrs)]

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/abbrev.rkt

@@ -233,7 +233,7 @@
   (make-Struct name parent flds proc poly pred))
 
 ;; Function type constructors
-(define/decl top-func (make-Function (list (make-top-arr))))
+(define/decl top-func (make-Function (list)))
 
 (define (asym-pred dom rng filter)
   (make-Function (list (make-arr* (list dom) rng #:filters filter))))

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/printer.rkt

@@ -207,7 +207,6 @@
 ;; Convert an arr (see type-rep.rkt) to its printable form
 (define (arr->sexp arr)
   (match arr
-    [(top-arr:) 'Procedure]
     [(arr: dom rng rest drest kws)
      (define out (open-output-string))
      (define (fp . args) (apply fprintf out args))

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/structural.rkt

@@ -72,8 +72,7 @@
      ;; Non Types
      [Result (#:co #:co #:co)]
      [Values ((#:listof #:co))]
-     [AnyValues ()]
+     [AnyValues ()]))
-     [top-arr ()]))
 
 (begin-for-syntax
   (define-syntax-class type-name

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/subtype.rkt

@@ -98,8 +98,6 @@
 ;; simple co/contra-variance for ->
 (define (arr-subtype*/no-fail A0 s t)
     (match* (s t)
-      ;; top for functions is above everything
-      [(_ (top-arr:)) A0]
       ;; the really simple case
       [((arr: s1 s2 #f #f '())
         (arr: t1 t2 #f #f '()))