diff --git a/whalesong/lang/private/traced-app.rkt b/whalesong/lang/private/traced-app.rkt
index 738ee4b..1dbbb16 100644
--- a/whalesong/lang/private/traced-app.rkt
+++ b/whalesong/lang/private/traced-app.rkt
@@ -21,5 +21,6 @@
          (syntax/loc stx
            (with-continuation-mark key 'pos
                                    (#%plain-app operator operands ...))))]
-      [else
-       stx])))
+      [(_)
+       (syntax/loc stx
+         (#%app))])))