[Haskell-cafe] Warning when attempting to install cabal-dev on the latest HP

http://hpaste.org/69885 The warning in that paste occurs when I attempt $ cabal update $ cabal install cabal-dev This is curious because it wants to install a previous version of mtl. I can't figure out why. There doesn't seem to be any dependency between cabal-dev and mtl. According to hackage, the dependencies for cabal-dev are: cabal-dev -> (base, Cabal) Cabal -> (base, filepath) filepath -> (base) base -> () The dependencies for mtl are (just to show no conflicts) mtl -> (base, transformers) transformers -> (base) base -> () And there's not a versioning conflict with base. Why is cabal insisting on backdating mtl then?