Please apply the following forward-and-backward compatible diff for SBCL.
closure-header-widetag is pending removed in the next release.
diff --git a/ginspect.lisp b/ginspect.lisp
index 3d448f8..a5ad37d 100644
--- a/ginspect.lisp
+++ b/ginspect.lisp
@@ -252,8 +252,7 @@
(inspected-standard-object-elements object)))
#+:sbcl
(defmethod inspected-parts ((object function))
- (let* ((type (sb-kernel:widetag-of object))
- (object (if (= type sb-vm:closure-header-widetag)
+ (let ((object (if (sb-kernel:closurep object)
(sb-kernel:%closure-fun object)
object)))
(values (format nil "FUNCTION ~S.~@[~%Argument List: ~A~]." object
