[wtfishackernews]

For json marshalling, I would defer to the underlying type's marshalling if it's present, and return `null` otherwise.

[shhsshs]

I think this is appropriate in some cases but not others. For example how does the JSON value distinguish between `Some(null)` and `None`?

[dialogbox]

IMO using Optional type means the inner value must be not null. And if it's Some(null), it should mean exactly same as None.