I noticed a mistake in one of the examples in the hyperspec, and went looking for an errata. I saw this page on cliki but didn't find the issue there, so I am wondering if the "comprehensive" list is elsewhere:
http://www.cliki.net/Proposed%20ANSI%20Revisions%20and%20Clarifications
FWIW, the issue is in the second example under the documentation for SHADOW[1].
(package-shadowing-symbols (make-package 'temp)) => NIL (find-symbol 'car 'temp) => CAR, :INHERITED
FIND-SYMBOL does not accept a symbol as the first argument. All the Lisps that I have checked this on signal an error.
Also, I think the first example should be modified to:
(package-shadowing-symbols (make-package 'temp :use '("CL")))
SBCL by default does not use the CL package. So (find-symbol "CAR" 'temp) returns NIL, NIL instead. It took me a while to figure why the spec example returned a different set of values.
Chaitanya
1. http://www.lispworks.com/documentation/HyperSpec/Body/f_shadow.htm