// learn from null constant

The non-null case changed to work for any expression determined to be non-null, not just constants. Does this need to change too? #Closed

Refers to: src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs:2076 in e8567ea. [](commit_id = e8567ea, deletion_comment = False)

Done review pass (commit 4)

        // learn from null constant

I don't think so. I think this can stay as-is.

There are two categories: (1) null constant (most confidence of nullness), and (2) maybe-null expressions (this is the most conservative inference). I don't think we can learn from a maybe-null expression, because it offers less confidence than a null constant (the null should definitely keep a maybe-null state) or a not-null expression (that inference is stronger, more conservative, than a maybe-null inference).

In reply to: 495802426 [](ancestors = 495802426)

Refers to: src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs:2076 in e8567ea. [](commit_id = e8567ea, deletion_comment = False)