[m-dev.] Repeated type variables in existentially quantified data constructors

[Peter Wang]

On Mon, 22 Jul 2024 11:33:22 +1000 Julien Fischer <jfischer at opturion.com> wrote:
> Hi,
> 
> I assume the fact that the frontend accepts existentially quantified
> data constructors
> with repeated type variables is an oversight, e.g.
> 
>     :- type process_unit
>          ---> some [T, T] process_unit(T)
> 
> The above type causes all four of our code generators to abort.

Yes, Zoltan and I both think it should be rejected. It was brought up in
the recent thread "Require subtypes to repeat existential type vars and
constraints exactly."

Peter