olly 5b3ed8286c Add non-null by default to source package (last one!)
Note on UnknownNull: Where there exists a generically typed
base class and both null and non-null types are permitted,
we need to clear the default non-null that's otherwise
propagated everywhere. This then lets the nullness of the
type work properly.

PiperOrigin-RevId: 295582444
2020-02-17 17:40:30 +00:00
..