Disassociate & associate

[erisco]

Not sure about the names but I am interested in two definitions like this:

disassociate :: forall u v s
  .   Contractable s u
  =>  R.Union u v s
  =>  Variant s
  ->  Either (Variant u) (Variant v)
disassociate s =
  case contract s of
    Just u -> Left u
    Nothing -> Right (unsafeCoerce s)

associate :: forall u v s
  .   R.Union u v s
  =>  R.Union v u s
  =>  Either (Variant u) (Variant v)
  ->  Variant s
associate (Left u) = expand u
associate (Right v) = expand v

Idealistically, the conversions would be with a variant of variants, but the inference for a big-union constraint I am anticipating to be a nightmare. This is more simplistic.