Generic operator overloading for immutable types?

[Kagamin via Digitalmars-d-learn]

On Tuesday, 13 June 2017 at 19:29:26 UTC, Gary Willoughby wrote:
> Is it possible for the `result` variable in the following code 
> to be returned as an immutable type if it's created by adding 
> two immutable types?

Why do you even want that? Such plain data structure is 
implicitly convertible to any const flavor: 
https://dpaste.dzfl.pl/c59c4c7131b2