diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-env.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-env.rkt
index 7b2b241a..d0fec520 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-env.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-env.rkt
@@ -964,9 +964,7 @@
 
 ;; Section 6.2 (Classes)
 [object% (make-Class #f null null null null)]
-[is-a? (-> (make-Instance (make-Class #f null null null null))
-           (make-ClassTop)
-           -Boolean)]
+[is-a? (-> Univ (make-ClassTop) -Boolean)]
 
 ;; Section 9.1
 [exn:misc:match? (-> Univ B)]