fa6399ff81
The added messages handle the situation in which null safety is enabled by default but is turned off either by language version or by explicitly passing --enable-experiment=no-non-nullable Change-Id: Iec43daf19a80f555e838635c83542fdb243b8ed4 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/168647 Reviewed-by: Jens Johansen <jensj@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com>