Proposal for non-nullable types in Dart

I think that non-nullable types by default are one of Dart's biggest missed opportunities, so I'm really hoping that the Dart team ends up adopting this.

This is also a really great example of the DEP system in action. DEPs (Dart Enhancement Proposals) allow anyone to suggest improvements to the Dart platform, and work with the Dart team to determine if it can be accepted and implemented. This means that individual community members can advance the language forward and that's exactly what's happening here. The author of the proposal, Patrice Chalin, is not on the Dart team but that hasn't stopped him from creating an awesome proposal that has earned praise from Dart team members.