src/class-output.lisp: Leave `*instance-class*' unbound at top-level.

diff --git a/src/class-output.lisp b/src/class-output.lisp
index ef82355..45a4909 100644 (file)
--- a/src/class-output.lisp
+++ b/src/class-output.lisp
@@ -542,7 +542,7 @@
 ;;; Implementation output.
 
 (export '*instance-class*)
-(defvar *instance-class* nil
+(defvar-unbound *instance-class*
   "The class currently being output.
 
    This is bound during the `hook-output' traversal of a class layout for