The compilation command should states which packages are used and avoid the default mechnasim that automatically search for them.

This can be done by the flags -hide-packages and then -package foo

> My ghc does not have a `--hide-packages` option.
> 
> Could you just show the build problem that you are suggesting I work
> around? --[[Joey]]


> Thanks npouillard, I see the problem now.
> <http://stackoverflow.com/questions/2048953/control-monad-state-found-in-multiple-packages-haskell>
> 
> I've added "-ignore-package monads-fd" to GHCFLAGS. I hope I don't
> really have to hide all packages and individually turn them back on;
> surely this monads-fd/mtl conflict is an exception, and Haskell's module
> system is not a mess of conflicting modules? --[[Joey]] [[done]]