Designing Nullable Reference Types in F#

Together with C#, F# will be incorporating nullability as a concept for .NET reference types. From the F# perspective, this fits with the default non-nullness of other F# types. But compatibility with existing code makes designing this a wild ride!

In this talk, we'll briefly explain what nullability means for F#, some existing mitigations for null in the language, and how we must consider compatibility with everything in mind. This deep dive into language design should give you an idea about what it is like designing a nontrivial feature that improves existing code while remaining compatible with it.