draft proposal for Sum Types for D

[rikki cattermole]

On 30/11/2022 4:10 AM, 12345swordy wrote:
> More importantly does it support?
> 
> sumtype A{
>      Null;
>      A a;
> }

At least in the theory that Null is equivalent to None which should be 
added to our type system and not just defined inline (as it is an 
existing hole).

Question is what to do when you do want to store that typed null.