When I look at the documentation of Control.Monad.Error [1] or Control.Applicative [2] it is not said that it re-exports Control.Monad.Instances. So maybe this behaviour is normal...

[1] http://hackage.haskell.org/packages/archive/mtl/2.0.1.0/doc/html/Control-Monad-Error.html
[2] http://hackage.haskell.org/packages/archive/base/4.3.0.0/doc/html/Control-Applicative.html


2011/2/24 Yves Parès <limestrael@gmail.com>
I have the same problem with instances of Functor.
For instance when I import Control.Applicative, to get the instance
"Functor ((->) a)" I also have to import Control.Monad.Instances.


2011/2/23 Daniel Fischer <daniel.is.fischer@googlemail.com>:
> On Wednesday 23 February 2011 14:14:46, Yves Parès wrote:
>> The latest, I think :
>> GHC 7.0.1,
>> mtl-2.0.1.0,
>> base-4.3.0.0
>
> Hmm, that's exactly what I have. Weirder and weirder.
> For the moment, I'm out of ideas.
>