diff --git a/src/util-proc.scm b/src/util-proc.scm
index 5e08745..2129515 100644
--- a/src/util-proc.scm
+++ b/src/util-proc.scm
@@ -28,6 +28,8 @@
 (module
  util-proc
  (
+  improper-list-info
+
   procedure-arity=?
   procedure-arity>=?
   procedure-arity>?