diff --git a/src/clj/com/rpl/specter/impl.cljx b/src/clj/com/rpl/specter/impl.cljx
index 96a00be..27eb76b 100644
--- a/src/clj/com/rpl/specter/impl.cljx
+++ b/src/clj/com/rpl/specter/impl.cljx
@@ -607,6 +607,11 @@
     ))
 
 (extend-protocol AllTransformProtocol
+  nil
+  (all-transform [structure next-fn]
+    nil
+    )
+
   ;; in cljs they're PersistentVector so don't need a special case
   #+clj clojure.lang.MapEntry
   #+clj