Incorrect value computed; SHIFTF is involved somehow
(funcall (compile nil '(lambda (b) (declare (optimize debug speed)) (identity (block nil (shiftf b :bad))))) :good)
==>
:BAD
(funcall (compile nil '(lambda (b) (declare (optimize debug speed)) (identity (block nil (shiftf b :bad))))) :good)
==>
:BAD