When the analyzer detects an unused parameter, it reports unused_element which can be ignored with an inline ignore like // ignore: unused_element. The analyzer will start reporting instead, unused_element_parameter. There are ignores in flutter/flutter that need to be updated to the new code. In order to incrementally migrate, they can be changed to // ignore: unused_element, unused_element_parameter.

After flutter/flutter is using a new enough analyzer, we can then change those to // ignore: unused_element_parameter.