The generic function compute-class-potential-initargs is called to compute the initialization arguments of a class. This set of valid initargs is used by make-instance when its arguments are checked.
class is the class passed to make-instance. That is, compute-class-potential-initargs specializes on the metaclass.
The other supplied method is on
standard-class. This consults the Relevant Methods, which are the applicable methods of make-instance,
shared-initialize. If any of the Relevant Methods have a lambda list containing
&allow-other-keys then initargs is t. Otherwise initargs is a list containing:
&keyarguments from Relevant Method lambda lists, and
:extra-initargs(see defclass for details of this), and
The list initargs contains no duplicates, and the result of compute-class-potential-initargs is cached so that it is not recomputed unless one of the Relevant Methods, the class or its class precedence list is altered.
LispWorks User Guide and Reference Manual - 20 Sep 2017