I use library msgpack-types-0.0.4 and I have a type:

newtype A = A Text

and I tried deriving MessagePack, deriving newtype MessagePack, standalone derivings, it seems nothing works (or I do something wrong). There is MessagePack instances for Text, for String, I thought that newtype deriving works always... Is it possible to derive this instance automatically? Why does not it work with newtype deriving?

EDIT:

An error message:

for newtype A = A Text deriving newtype MessagePack:

• Couldn't match representation of type ‘m Text’ with that of ‘m A’
    arising from the coercion of the method ‘fromObject’
      from type ‘forall (m :: * -> *).
                 (Applicative m, Monad m, MonadFail m) =>
                 Data.MessagePack.Object -> m Text’
        to type ‘forall (m :: * -> *).
                 (Applicative m, Monad m, MonadFail m) =>
                 Data.MessagePack.Object -> m A’
  NB: We cannot know what roles the parameters to ‘m’ have;
    we must assume that the role is nominal
• When deriving the instance for (MessagePack A)