Don't record nil as the macro ancestor of a form.

* eval.c (set_origin): Don't store nil value
in the origin_hash.

1 files changed, 2 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index e92c5845..ddbc17ae 100644
--- a/eval.c
+++ b/eval.c
@@ -223,7 +223,8 @@ val lookup_origin(val form)
 
 static val set_origin(val form, val origin)
 {
-  (void) sethash(origin_hash, form, origin);
+  if (origin)
+    sethash(origin_hash, form, origin);
   return form;
 }