Hello Georgi, I'm confused about WrappedMonoid. How can something have a Monoid instance already without having a Semigroup instance in the first place? But also what is the benefit of WrappedMonoid over the standard way of defining Semigroups and Monoids for your example data List a = Nil | Cons a (List a) instance Semigroup (List a) where Nil <> ys = ys Cons x xs <> ys = Cons x (xs <> ys) instance Monoid (List a) where mempty = Nil ? Cheers,John On Saturday, 14 September 2019, 19:18:01 UTC, Georgi Lyubenov <godzbanebane@gmail.com> wrote: Hello! Sorry if this is not the right place to ask! As of right now (14.09.2019) Data.Semigroup.WrappedMonoid is slated to be deprecated. I believe that this newtype is actually useful in tandem with DerivingVia, as it allows you to derive the Semigroup instance for something that has a Monoid instance already, as discussed in this twitter thread. Would it be possible to *not* deprecate it in the future, and instead keep it around for exactly this purpose? Cheers, Georgi_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries