[Haskell-beginners] Re: Debugging overlapping instances (mtl vs transformers)

[Paolo Losi]

On 09/09/2010 10:35, Paolo Losi wrote:

> Overlapping instances for Monad (Either String)
> arising from a use of `tstampToForecasts'
> at ThreeLab/Gfs.hs:94:32-55
> Matching instances:
> instance (Control.Monad.Trans.Error.Error e) => Monad (Either e)
> -- Defined in Control.Monad.Trans.Error
> instance Monad (Either e)
> -- Defined in mtl-1.1.1.0:Control.Monad.Error

Forgot to say... that's the error I get using cabal build