diff --git a/collects/mzlib/private/match/gen-match.ss b/collects/mzlib/private/match/gen-match.ss
index 0b272b8c4b..a1ec48e096 100644
--- a/collects/mzlib/private/match/gen-match.ss
+++ b/collects/mzlib/private/match/gen-match.ss
@@ -34,7 +34,7 @@
   ;; returns three values representing the pattern, the body and the failure symbol
   
   (define (parse-clause clause)
-    (syntax-case clause (=>)
+    (syntax-case* clause (=>) (lambda (a b) (eq? (syntax-e a) (syntax-e b)))
       [(pat) (match:syntax-err clause
                                "missing action for pattern")]
       [(pat (=> fail-sym))