-- | Get the 'Id' from a 'TyThing' if it is a id *or* data constructor thing. Panics otherwise
tyThingId :: TyThing -> Id
tyThingId (AnId id)                   = id
tyThingId :: TyThing -> Id
tyThingId (AnId id)                   = id
tyThingId (AnId id)                   = id