-- | Is this an algebraic 'TyCon' which is just an enumeration of values?
isEnumerationTyCon :: TyCon -> Bool
isEnumerationTyCon (AlgTyCon {algTcRhs = DataTyCon { is_enum = res }}) = res
+isEnumerationTyCon (TupleTyCon {tyConArity = arity}) = arity == 0
isEnumerationTyCon _ = False
-- | Is this a 'TyCon', synonym or otherwise, that may have further instances appear?
-- | Extract an 'AlgTyConRhs' with information about data constructors from an algebraic or tuple
-- 'TyCon'. Panics for any other sort of 'TyCon'
algTyConRhs :: TyCon -> AlgTyConRhs
-algTyConRhs (AlgTyCon {algTcRhs = rhs}) = rhs
-algTyConRhs (TupleTyCon {dataCon = con}) = DataTyCon { data_cons = [con], is_enum = False }
+algTyConRhs (AlgTyCon {algTcRhs = rhs}) = rhs
+algTyConRhs (TupleTyCon {dataCon = con, tyConArity = arity})
+ = DataTyCon { data_cons = [con], is_enum = arity == 0 }
algTyConRhs other = pprPanic "algTyConRhs" (ppr other)
\end{code}