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