diff --git a/collects/lang/private/teachprims.ss b/collects/lang/private/teachprims.ss
index e1ab3aa309..83d9800aa9 100644
--- a/collects/lang/private/teachprims.ss
+++ b/collects/lang/private/teachprims.ss
@@ -221,6 +221,7 @@ namespace.
   (lambda (x)
     (not (or (number? x)
              (boolean? x)
+             (empty? x)
              (pair? x)
              (symbol? x)
              (string? x)