diff --git a/collects/tests/typed-scheme/fail/port-to-list.rkt b/collects/tests/typed-scheme/fail/port-to-list.rkt
new file mode 100644
index 00000000..11ea3942
--- /dev/null
+++ b/collects/tests/typed-scheme/fail/port-to-list.rkt
@@ -0,0 +1,5 @@
+#lang typed/racket 
+(car (car
+      (parameterize ((current-input-port (open-input-string "2")))
+              ((inst port->list (List Number))))))
+
diff --git a/collects/typed-scheme/base-env/base-env.rkt b/collects/typed-scheme/base-env/base-env.rkt
index 282071b4..038fbb6b 100644
--- a/collects/typed-scheme/base-env/base-env.rkt
+++ b/collects/typed-scheme/base-env/base-env.rkt
@@ -902,7 +902,10 @@
 ;; scheme/port
 [port->lines (cl->* ([-Input-Port] . ->opt . (-lst -String)))]
 [port->bytes-lines (cl->* ([-Input-Port] . ->opt . (-lst -Bytes)))]
-[port->list (-poly (a) (->opt [(-> -Input-Port a) -Input-Port] (-lst a)))]
+[port->list
+ (-poly (a) (cl->*
+  (-> (-lst Univ))
+  (->opt (-> -Input-Port a) [-Input-Port] (-lst a))))]
 [port->bytes (->opt [-Input-Port] -Bytes)]
 [port->string (->opt [-Input-Port] -String)]
 [with-output-to-string