* Rename __parameters__ to __args__, for typing.py compatibility
* Genericize, re.{Pattern,Match} and io.IO
* list != list[int], but list[int] == list[int] (and list[str] != list[int])
* Add a lazy __parameters__ that contains the unique type vars in __args__ (also for typing.py compatibility)
* make dict[str][str] fail, but dict[T, str][int] return dict[int, str]
* expose proxy type as types.GenericAlias
* Link to implementation
* Explicitly state that pickling or copying should work
Guido van Rossum
Ethan Smith
Łukasz Langa
Serhiy Storchaka