The procedure goops-error is called to raise an appropriate error
by the default methods of the following generic functions:
slot-missing (see slot-missing)
slot-unbound (see slot-unbound)
no-method (see no-method)
no-applicable-method (see no-applicable-method)
no-next-method (see no-next-method)
If you customize these functions for particular classes or metaclasses,
you may still want to use goops-error to signal any error
conditions that you detect.
Raise an error with key goops-error and error message constructed
from format-string and arg .... Error message
formatting is as done by scm-error.