Hi David,

I'm going to add Type Families support to the Haddock HTML backend.

Great!

What would be the best way to do it? I'm thinking it could work similar to how classes and instances are currently rendered, so that type/data/newtype instances are collected and attached to type family declarations. Is this too simplistic? Should we render type/data/newtype instances as separate entities in the module documentation instead (and perhaps do the same thing with class instances)?

Currently, when packages export instances that belong to classes from other packages, those instances are not documented anywhere. An advantage of having instances as separate entities in the exporting module documentation is that no instances are "lost".

I think the basic idea to treat class and family declarations and instances in essentially the same way is a good. Losing instances is of course bad for both classes and families. I think it still makes sense to bunch the instances of one class or one family up in a block. In fact, for type synonyms instances, there are many applications, where this is really important for readability. Please also remember that family declarations and instances can be nested in class declarations and instances (as associated types). Manuel