2 files changed, 6 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index 493645d3..766378f7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2014-12-05  Kaz Kylheku  <kaz@kylheku.com>
 
+	* lib.c (set_diff): Bugfix: use member rather than find,
+	so that a nil set element is handled properly.
+
+2014-12-05  Kaz Kylheku  <kaz@kylheku.com>
+
 	* Makefile (INSTALL): Bugfix: touch -r $(2) does not work
 	right when $(2) is a wildcard like path/to/*.txr.  It touches files in
 	the source tree to the timestamp of the argument after -r.  Putting in
diff --git a/lib.c b/lib.c
index aba04b39..82eb4755 100644
--- a/lib.c
+++ b/lib.c
@@ -5998,7 +5998,7 @@ val set_diff(val list1, val list2, val testfun, val keyfun)
       val item = car(list1);
       val list1_key = funcall1(keyfun, item);
 
-      if (!find(list1_key, list2, testfun, keyfun))
+      if (!member(list1_key, list2, testfun, keyfun))
         ptail = list_collect(ptail, item);
     }
   }