1 files changed, 8 insertions, 7 deletions
diff --git a/def.lisp b/def.lisp
index c4ab58b..715ab7f 100644
--- a/def.lisp
+++ b/def.lisp
@@ -18,13 +18,14 @@ easily document uninitialized special variables."
   "Define a constant in a way that is redefinable whenever the form is
 reevaluated."
   (assert (good-muffed-var-name-p name :muffer "+"))
-  `(progn
-     (handler-bind ((error
-                      (lambda (&rest ignore)
-                        (declare (ignore ignore))
-                        (invoke-restart 'cl:continue))))
-       (makunbound ',name))
-     (defconstant ,name ,value ,@(when doc (list doc)))))
+  (let ((newval (gensym "NEWVAL-")))
+   `(let ((,newval ,value))
+      (handler-bind ((error
+                       (lambda (&rest ignore)
+                         (declare (ignore ignore))
+                         (invoke-restart 'cl:continue))))
+        (makunbound ',name))
+      (defconstant ,name ,newval ,@(when doc (list doc))))))
 
 (defmacro class (name (&rest supers) &body slots-and-options)
   "Define a class.