RFC: Flow-Sensitive Nullability

I guess to make it concrete, what would be the migration plan you’d suggest based on your experience?

  1. Users annotate one file at a time with Nullable where known to be possibly null
  2. Users annotate the file as “default nonnull”
  3. Users turn on a flag to enable nullable checks assuming non-annotated pointers are Nonnull, and see warnings about potential unsafe null use.

Is that right?