The standard requires that an error is signaled when a generic function is called and
define-method-combination. The latter includes the
standardized method combinations like progn, and, etc.
In CMUCL, this generic function is called in the above erroneous
cases. The parameter gf is the generic function being
called, and args is a list of actual arguments in the generic
function call.
This method signals a continuable error of type
pcl:no-primary-method-error.