In Flutter 1.17.0, a breaking change was made to ParentDataWdiget. A new method debugTypicalAncestorWidgetClass requires users to override and return Type of its ancestor widget.

However, the ancestor could be a generic type, and Dart does not support generic type literals.

Since it is a relatively uncommon pattern in Flutter (AFAIK), and the solution is tricky to get around this Dart limitation, it could be confusing whether the user should return with or without generic type arguments. So mentioning this in documentation for relevant APIs can be helpful.