From 78e460ec9a1cdad1c90eef0eccccf8782789774b Mon Sep 17 00:00:00 2001
From: Gerd Heber <gheber@hdfgroup.org>
Date: Wed, 15 Jul 2015 17:45:00 -0500
Subject: [PATCH] NULL is a permissible value for INTR.

---
 src/chain-complexes.lisp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/chain-complexes.lisp b/src/chain-complexes.lisp
index 189f5ed..61ef51e 100644
--- a/src/chain-complexes.lisp
+++ b/src/chain-complexes.lisp
@@ -215,7 +215,7 @@ instances via the standard constructor MAKE-INSTANCE."
   (declare
    (type chain-complex sorc trgt)
    (fixnum degr)
-   (type intr-mrph intr)
+   (type (or intr-mrph null) intr)
    (type strt strt)
    (list orgn))
   "Returns an instance of MORPHISM. Use this function instead of creating