Steel Bank Common Lisp

I can't seem to find the manual on sb-mop, but once I redefine a class
not to have a certain super-class, I'd expect the super-class to lose
the class from its subclasses as well...


* (defclass vegetable () ())

#<STANDARD-CLASS VEGETABLE>
* (defclass tomato (vegetable) ())

#<STANDARD-CLASS TOMATO>
* (sb-mop:class-direct-subclasses (find-class 'vegetable))

(#<STANDARD-CLASS TOMATO>)
* (defclass tomato () ()) ; tomato turns out to be fruit

#<STANDARD-CLASS TOMATO>
* (sb-mop:class-direct-subclasses (find-class 'vegetable))

(#<STANDARD-CLASS TOMATO>)

Now I was expecting NIL