`WriterT` currently has `Monad` and `Eq` instances, but there are many more that it could have. Some examples that I think can be added are: - [x] Functor (#628) - [x] Apply (#628) - [x] Applicative (#628) - [x] FlatMap (#628) - [x] MonadFilter (#696) - [x] Alternative (#696) - [x] MonadCombine (#696) - [x] ApplicativeError (#689) - [x] MonadError (#689) - [x] Show (#928) - [x] Foldable - [x] Traverse - [x] Bifunctor (#673) - [x] CoflatMap (#1049) - [x] Comonad - [x] Semigroup (#1014) - [x] Monoid (#1014) - [x] SemigroupK (#696) - [x] MonoidK (#696)
WriterTcurrently hasMonadandEqinstances, but there are many more that it could have. Some examples that I think can be added are: