From 9c48cee548dd6354a4cf5da4b17e648e6b800893 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sat, 22 Sep 2007 00:50:09 +0000
Subject: [PATCH] handle case where native trace in sub-cont is NULL

svn: r7396
---
 src/mzscheme/src/fun.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index 5251ad1c95..8518221f59 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -4997,6 +4997,7 @@ internal_call_cc (int argc, Scheme_Object *argv[])
 	    /* Maybe a single-function loop, where we re-allocated the
 	       last pair in the trace, but it's the same name: */
 	    || (SCHEME_PAIRP(ret)
+                && sub_cont->native_trace
 		&& SCHEME_PAIRP(sub_cont->native_trace)
 		&& SAME_OBJ(SCHEME_CAR(ret), SCHEME_CAR(sub_cont->native_trace))
 		&& SAME_OBJ(SCHEME_CDR(ret), SCHEME_CDR(sub_cont->native_trace))))