Thomas proposed some time ago to use cabal-install for haskell libraries. That is why I propose to drop haskell-gtk and it's buildchain, so we can drop:

haskell-gtk haskell-pango haskell-glib haskell-cairo haskell-hashtables

I also checked package status and I can not find it there :) [1] I would like to leave just xmonad, xmobar and some other haskell packages in [community].

If no one disagrees, I'll drop the packages tommorow.

[1] https://www.archlinux.org/news/managing-haskell-packages-with-ghc-782/