Test that the NNBD implementation does not allow a nullable expression
where a non-null value is expected for language constructs.
Similarly that null-aware operations used on non=-nullable values
are caught.
Change-Id: I877e9b464666698b7f25b355b0474eb171bfc4b3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/134160
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Lasse R.H. Nielsen
3a36439abe