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

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!