We need to add role annotations for 7.8

[Andres Löh]

[Sorry for the self-reply.]

Oh, perhaps I actually understand this:

> Please forgive my ignorance w.r.t. roles, but why aren't all of these
> representational?
>
>> Map k v -- k: nominal, v: represententional
>> Set a -- k: nominal
>
> AFAIK both Map and Set are "normal" datatypes. Not GADTs, no type
> families involved. Why would anything need to be "nominal" then?

Is this because the integrity of these types relies on the Ord
instance being sane, and a newtype could have a different Ord instance
defined?

Cheers,
  Andres