§5.4.2.(b) Method binding guards

A base method binding guard may access parameters as passed to the base method. Parameter mappings are not considered.
Additionally, for after callin bindings, the identifier result may be used to refer to the result of the base method (if any).

Note:

In order to achieve the same effect of accessing the base method's result, a regular binding guard (not a base guard) must use a suitable parameter mapping (see §4.4.(c)).