On Dec 13, 2016 4:01 AM, "Oleg Grenrus" <oleg.grenrus@iki.fi> wrote: Hi, continuing pushing the adoption Data.Functor.Classes, I wrote a small package `functor-classes-compat` [1]. It provides lifted (Eq1, Ord1, etc.) classes for types in `containers`, `vector` and `unordered-containers`(not for Sequence or Tree yet though). Thanks for working on this. Obviously, some of these really belong in containers. I'll try to add them today. I guess there is no way they could depend on `transformers` to provide instances in build plans with `base < 4.9`, I'm not sure when I'll have time to write patches for the actual packages myself. No, I don't think that's likely. One option might be to add these instances to transformers when compiling with older base, but I don't know if Ross Paterson will want them. Current implementations are naive, but more obviously correct. More than what?