Adding the ?. operator to D

[Per Nordlöw]

On Wednesday, 16 September 2020 at 19:01:28 UTC, Jacob Carlborg 
wrote:
>>      C ? C.EXPR : nullable(EXPR).init
>> 
> I would like that. It should work for an Optional/Nullable type 
> as well.

You're saying you want the variant with `nullable` and make 
`nullable` builtin?

A interesting alternative would be to return `&C.EXPR` on success 
and null otherwise. Kind of like the `in` operator does.