diff --git a/lib/erlang/transpile.sx b/lib/erlang/transpile.sx
index 1cb64268..915d31b6 100644
--- a/lib/erlang/transpile.sx
+++ b/lib/erlang/transpile.sx
@@ -1895,15 +1895,20 @@
 
 (define er-env-derived-from?
   (fn (env target-env)
+    ;; Object-identity check, NOT value `=`. On evaluators where dict `=`
+    ;; is structural/deep, comparing closure envs (which are large and
+    ;; cyclic — a module fun's env references the fun) does not terminate.
+    ;; `identical?` is pointer identity on every host and is the actual
+    ;; intended semantics: "is this the same env object".
     (cond
-      (= env target-env) true
+      (identical? env target-env) true
       :else
         (let ((ks (keys env)) (found-ref (list false)))
           (for-each
             (fn (i)
               (when (not (nth found-ref 0))
                 (let ((v (get env (nth ks i))))
-                  (when (and (er-fun? v) (= (get v :env) target-env))
+                  (when (and (er-fun? v) (identical? (get v :env) target-env))
                     (set-nth! found-ref 0 true)))))
             (range 0 (len ks)))
           (nth found-ref 0)))))