The idea is that major type features should be exposed via common metadata and represented in the IL. This allows other languages to unambiguously use such type

The idea is that major type features should be exposed via common metadata and represented in the IL. This allows other languages to unambiguously use such types. Non-nullable references are definitely a big enough feature. Conceptually, it's bigger than Nullable<T> which is just a wrapper you can toss around any struct and could be done purely as a library (though I understand there's some delicacy as far as unboxing null and converting that to a Nullable<T>). I'm not sure which interpreter you're referring to, but languages don't need to emit similar IL for executable code (why would it matter?). What counts is that the type defs end up exported in the same manner. If making a class in VB emitted substantially different IL than C#, that'd be an issue.