interactTopCmpNat :: [Xi] -> Xi -> [Pair Type]
interactTopCmpNat [s,t] r
  | Just EQ <- isOrderingLitTy r = [ s === t ]
interactTopCmpNat :: [Xi] -> Xi -> [Pair Type]
interactTopCmpNat [s,t] r
  | Just EQ <- isOrderingLitTy r = [ s === t ]
interactTopCmpNat [s,t] r
  | Just EQ <- isOrderingLitTy r = [ s === t ]