This is also how the Monoid instance of basically everything with an Applicative instance is defined. The only one that I feel should differ from the others is Maybe, and that's getting fixed when Semigroup becomes a superclass of Monoid.

On Tue, Nov 28, 2017 at 2:22 PM, M Farkas-Dyck <m.farkasdyck@gmail.com> wrote:

On 28/11/2017, Andrew Martin <andrew.thaddeus@gmail.com> wrote:
> instance (Applicative m, Monoid a) => Monoid (ReaderT r m a)

> I believe there is good reason to prefer the first instance over the other
> two.

+1

This is also how the `Monoid` instance of `(->)` is defined.

-Andrew Thaddeus Martin