gseitz/scalaz — comment on commit a380e9491a253eace05adef1e9004575323e57de
File: core/src/main/scala/scalaz/std/Either.scala line 237
By retronym:

To be consistent with other type classes, create type class implementation traits,such that `EitherRightMonoid` extends `EitherRightSemigroup`. Lookt at `Tuple2` for an example.