From 06315bf0fab0cfab299a8fa98b26221471f4e389 Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Fri, 29 Mar 2013 11:57:26 -0500
Subject: [PATCH] syntax error check fix

closes PR 13639
---
 collects/redex/private/reduction-semantics.rkt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/collects/redex/private/reduction-semantics.rkt b/collects/redex/private/reduction-semantics.rkt
index a0c3ed8ac2..a1cfe033d6 100644
--- a/collects/redex/private/reduction-semantics.rkt
+++ b/collects/redex/private/reduction-semantics.rkt
@@ -509,7 +509,9 @@
                                                      #,(to-lw/uq/proc tl-pat)))
                                            (syntax->list #'(tl-id ...))
                                            (syntax->list #'(tl-pat ...))))
-                             (list fvars ...))))]))
+                             (list fvars ...))))]
+      ;; just skip over junk here, since syntax error checks elsewhere will catch this
+      [_ #f]))
   
   (define (reduction-relation/helper stx orig-name orig-red-expr lang-id rules shortcuts 
                                      lws