draft proposal for Sum Types for D

[deadalnix]

On Wednesday, 30 November 2022 at 04:09:10 UTC, Paul Backus wrote:
> Off the top of my head, I can tell you that most of the code 
> volume comes from having to copy and paste each function 4 
> times to handle different mutability qualifiers (mutable, 
> const, immutable, inout). Which is tedious (and a symptom of a 
> missing language feature IMO), but not exactly complex.

It's amazing how many of these these discussion surfaced. This is 
the actual things that we need to fix.

And when they are fixed, if we still feel like the need for 
builtin sum types remains, then yes, go for it. In the meantime, 
it is just adding to the pile of things that don't really work.