Control.Monad.State found in multiple packages haskell
cabal, hackage, haskell
Solution
You have several options. Either:
- `ghc-pkg hide monads-fd`. This will cause GHC and GHCi to ignore the presence of the `monads-fd` by default until you later `ghc-pkg expose monads-fd`, but software installed by Cabal will still be able to build against it.
- Use the `{-# LANGUAGE PackageImports #-}` pragma, and change your import statement to `import "mtl" Control.Monad.State`.
- Use Cabal to build your project, and specify `mtl` in the `Build-depends` line.
The first is best for casual hacking, and the last is best for production builds.
These all assume you want the `mtl` module and not the `monads-fd` module; otherwise swap them.
Problem
While evaluating the line "import Control.Monad.State" in a Haskell module, GHC gives me the following error: ``` Could not find module `Control.Monad.State': it was found in multiple packages: monads-fd-0.0.0.1 mtl-1.1.0.2 Failed, modules loaded: none. ``` How do I resolve this conflict?