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 cc80fabf..a99975f7 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
@@ -1210,7 +1210,7 @@
 [make-parameter (-poly (a b) (cl-> [(a) (-Param a a)]
                                    [(b (a . -> . b)) (-Param a b)]))]
 [make-derived-parameter (-poly (a b c d) (-> (-Param a b) (-> c a) (-> b d) (-Param c d)))]
-[parameter? (make-pred-ty (-poly (a b) (-Param a b)))]
+[parameter? (make-pred-ty (-Param -Bottom Univ))]
 [parameter-procedure=? (-poly (a b c d) (-> (-Param a b) (-Param c d) B))]
 
 [current-parameterization (-> -Parameterization)]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/typecheck-tests.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/typecheck-tests.rkt
index fe777ac9..6fe278b5 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/typecheck-tests.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/typecheck-tests.rkt
@@ -1948,6 +1948,14 @@
              #:ret (ret (list (-val 'a) (-val 'b)))]
        [tc-e (call-with-input-bytes #"abcd" (lambda: ([input : Input-Port]) (values 'a 'b)))
              #:ret (ret (list (-val 'a) (-val 'b)))]
+
+       [tc-e (lambda: ([x : (U (Parameter Symbol) Symbol)])
+               (if (parameter? x)
+                   (x)
+                   x))
+             #:ret (ret (t:-> (t:Un (-Param -Symbol -Symbol) -Symbol) -Symbol))
+             #:expected (ret (t:-> (t:Un (-Param -Symbol -Symbol) -Symbol) -Symbol))]
+
         )
   (test-suite
    "tc-literal tests"