Proposal: Add a wrapped applicative type to Data.Monoid

[Daniel Cartwright]

I see this as being generally (as in, to the users of Haskell as a whole)
useful:

newtype Ap f a = Ap { getAp :: f a }
  deriving (Applicative, Eq, Foldable, Functor, Generic, Generic1
                ,Monad, Ord, Read, Show, Traversable)

Some hand-written instances:
instance (Applicative f, Semigroup a) => Semigroup (Ap f a) where
  (Ap x) <> (Ap y) = Ap $ liftA2 (<>) x y

instance (Applicative f, Monoid a) => Monoid (Ap f a) where
  mempty = Ap $ pure mempty
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