[Haskell-cafe] Injective type families for GHC

[Roman Cheplyaka]

Huh, that's a tough question! I've certainly run into the
non-injectivity issue quite a few times, but it's hard to remember a
single specific case.

You may want to look at the uses of data families. In my experience, a
programmer would often (almost always?) prefer a type family, but has to
resort to a data family when s/he runs into non-injectivity.

Is your design described anywhere?

On 09/02/15 17:58, Jan Stolarek wrote:
> Haskellers,
> 
> I am finishing work on adding injective type families to GHC. I know that in the past many people 
> have asked for this feature. If you have use cases for injective type families I would appreciate 
> if you could show them to me. My implementation has some restrictions and I want to see how 
> severe these restrictions are from a practical point of view.
> 
> Janek
> 
> ---
> Politechnika Łódzka
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