Which language futures make D overcompicated?

[jmh530]

On Friday, 9 February 2018 at 13:47:51 UTC, Atila Neves wrote:
> On Friday, 9 February 2018 at 08:27:21 UTC, Nick Sabalausky
>>
>> And yes, things like "inout", "auto ref" or whatever, and 
>> such, strike me as indicative of more fundamental design 
>> flaws. (Not "flaw" in the sence of "mistakes" necessarily, but 
>> "flaw" in the sence of "there must be a better way to design 
>> these things...")
>>
>> [...]
>
> Yeah, something like traits in Rust or typeclasses in Haskell 
> would be a lot better. Fortunately, one can kinda-sorta get 
> there with a library solution. Check out `@implements` in 
> https://github.com/atilaneves/concepts
>

I'm confused. While I get how @implements resolves the same 
issues as Rusts's traits, I don't see how traits resolve the same 
issues as inout/auto ref. My understanding is that inout and auto 
ref mean you don't have to write multiple versions of the 
relevant functions. Moreover, while one could use templates to do 
something similar, inout/auto ref are designed to reduce code 
bloat. I don't think Rust's traits can accomplish the same thing, 
but I'm not familiar enough with Haskell's typeclasses to know.