The AMOP defines that the standard primary method for
validate-superclass
should return true if the class of one of the arguments is
standard-class
and the class of the other is
funcallable-standard-class
.
In LispWorks, objects of these metaclasses are not completely compatible, so
validate-superclass
will return false in these cases.
Beware that defining a class that mixes
standard-class
and
funcallable-standard-class
can lead to inconsistencies with the predicate
functionp
, the type
function
and the class
function
.