Abel Nieto

1. Pattern matching already works. 2. Thanks for the suggestions. We're still deciding how general the flow sensitivity will be.

Implemented the following algorithm in https://github.com/abeln/dotty/commit/740790e2d21c251980ea3acf167f4db53ba2e801 Let `NN(cond, true/false)` be the set of `TermRefs` that we can infer to be non-null in `cond` if `cond` is true/false, respectively. Then define...

We can type all of https://github.com/abeln/dotty/blob/explicit-null/tests/pos/explicit-null-flow.scala We still need to propagate the new type information _inside_ the conditional: ``` val x: String|Null = ??? if (x != null && x.length...

Another TODO: support for the feature in TASTy.

> We still need to propagate the new type information inside the conditional: This is now done in https://github.com/abeln/dotty/commit/74039292ea9e10fbc23639ffcf5afee00585adf6 So we can now additionally support ``` val x: String|Null =...

https://github.com/abeln/dotty/issues/7#issuecomment-445057335 is still a TODO. Another TODO: make sure that the error message mentions the refined type and not the symbol type. e.g. ``` 2 class Foo { 3 class...

Algorithm for propagating nullability inside a condition: ``` When typing `A && B` - type `A` - compute NN(A) - type B in the context augmented with NN(A, true) Similarly,...

We now also support inference within blocks. See https://github.com/abeln/explicit-null-docs/blob/master/migration.md#non-local-control-flow-and-blocks for details. This allows to handle cases like ```scala def foo(x: String|Null): String = { if (x == null) return ""...

@olhotak do you remember what we agreed for this one?

This should be fixed when we port the standard library, but the more general solution will require binary compatibility.