[Haskell-cafe] Why can't I promote data family constructors, and what to do instead?

[Tom Ellis]

On Sat, Sep 16, 2023 at 08:45:59AM -0400, Ryan Scott wrote:
> Regarding the first question ("Is this restriction *really* necessary?"), I
> think the answer is likely "no", at least for most data family instances.
> This discussion [1] is the most up-to-date reference on the history and
> motivations behind the current restriction. 
>
> [1] https://github.com/ghc-proposals/ghc-proposals/discussions/456

Very interesting. Thanks Ryan!