diff --git a/collects/typed-scheme/private/base-env.rkt b/collects/typed-scheme/private/base-env.rkt
index d2252e2b..56651fef 100644
--- a/collects/typed-scheme/private/base-env.rkt
+++ b/collects/typed-scheme/private/base-env.rkt
@@ -536,7 +536,8 @@
                  (cl-> [((-HT a b) a) b]
                        [((-HT a b) a (-> c)) (Un b c)]))]
 [hash-ref! (-poly (a b)
-                  (cl-> [((-HT a b) a (-> b)) b]))]
+                  (cl-> [((-HT a b) a b) b]
+                        [((-HT a b) a (-> b)) b]))]
 [hash-has-key? (-poly (a b) (-> (-HT a b) a B))]
 [hash-update! (-poly (a b)
                      (cl-> [((-HT a b) a (-> b b)) -Void]