Hi, I've pushed a patch to haskeline's repo which will let it build with the new version of mtl. This change will be included in the next release of haskeline (0.7). Best, -Judah On Fri, Apr 27, 2012 at 6:23 AM, Christian Maeder wrote:

Hi,

trying to install haskeline together with other packages using cabal-install-0.14.0 resulted in a failure due to a too restrictive constraint.

...

cabal install mtl haskeline --dry-run Resolving dependencies... In order, the following would be installed (use -v for more details): haskeline-0.4

# because mtl-2.1.1 is already installed

This installation of haskeline-0.4 fails!

...

cabal install transformers haskeline --dry-run Resolving dependencies... In order, the following would be installed (use -v for more details): mtl-1.1.1.1 haskeline-0.6.4.6

# transformers-0.3.0.0 is already installed

...

cabal install haskeline --dry-run Resolving dependencies... In order, the following would be installed (use -v for more details): transformers-0.2.2.0 mtl-2.0.1.0 haskeline-0.6.4.6

Cheers Christian