allow values with define-new-subtype types as functions

typed-racket-lib/typed-racket/typecheck/tc-funapp.rkt

@@ -153,6 +153,8 @@
       [_ (tc-error/expr
            "Wrong number of arguments to parameter - expected 0 or 1, got ~a"
            (length argtys))])]
+    [(Distinction: _ _ t)
+     (tc/funapp f-stx args-stx t args-res expected)]
     ;; resolve names, polymorphic apps, mu, etc
     [(? needs-resolving?)
      (tc/funapp f-stx args-stx (resolve-once f-type) args-res expected)]

typed-racket-test/succeed/define-new-subtype-function.rkt

@@ -0,0 +1,8 @@
+#lang typed/racket
+
+(define-new-subtype F (make-F (-> Real Real)))
+
+(: app : F Real -> Real)
+(define (app f x)
+  (f x))
+