For analyzer backend only:
* Implements `x!`
* Uses non-null type info where possible to elide null checks.
* Does not yet reify.
No hurry on this - starting to look at what's there. Some notes:
* NNBD doesn't seem to be exposed directly on DartType yet.
* x!.y doesn't seem to parse - need to write (x!).y.
* Can't run existing tests yet - `package:expect`, etc., have NNBD errors.
Change-Id: I58c24c950d00f3a40d789d4a7adf049786977c50
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/103040
Commit-Queue: Vijay Menon <vsm@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>
Vijay Menon
77f2603052