3.5.1.9 Errors When Calling a Next Method

If call-next-method is called with arguments, the ordered set of applicable methods for the changed set of arguments for call-next-method must be the same as the ordered set of applicable methods for the original arguments to the generic function, or else an error should be signaled.

The comparison between the set of methods applicable to the new arguments and the set applicable to the original arguments is insensitive to order differences among methods with the same specializers.

If call-next-method is called with arguments that specify a different ordered set of applicable methods and there is no next method available, the test for different methods and the associated error signaling (when present) takes precedence over calling no-next-method.