[Hs-Generics] RE: Traversible Functor Data, or: X marks the spot (Re: Haddock version during build)

| I suggest to separate the vacuous from the proper instances, | and to expose only the former via Data.Generics. That way, | the convenience is only an import away, but doesn't get in | the way of non-standard applications. Probably the right thing is to use the libraries modification process to effect the change. (For what it's worth, I don't feel strongly about this.) Simon