Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: gtk2hs-hello (user goal)
rejecting: gtk2hs-hello-1.1.0.0 (global constraint requires ==1.0.0.0)
trying: gtk2hs-hello-1.0.0.0
next goal: gtk3 (dependency of gtk2hs-hello-1.0.0.0)
rejecting: gtk3-0.14.1, 0.14.0, 0.13.9, 0.13.8, 0.13.7, 0.13.6, 0.13.4,
0.13.3, 0.13.2, 0.13.1, 0.13.0.3, 0.13.0.2, 0.13.0.1, 0.13.0.0 (conflict:
gtk2hs-hello => gtk3>=0.12.5.6 && <0.13)
trying: gtk3-0.12.5.7
trying: mtl-2.2.1 (dependency of gtk3-0.12.5.7)
next goal: transformers (dependency of gtk2hs-hello-1.0.0.0)
rejecting: transformers-0.4.2.0/installed-21d..., 0.4.3.0, 0.4.2.0, 0.4.1.0
(conflict: gtk2hs-hello => transformers>=0.3.0.0 && <0.4)
rejecting: transformers-0.3.0.0 (conflict: mtl => transformers==0.4.*)
rejecting: transformers-0.2.2.1, 0.2.2.0, 0.2.1.0, 0.2.0.0, 0.1.4.0, 0.1.3.0,
0.1.1.0, 0.1.0.1, 0.1.0.0, 0.0.1.0, 0.0.0.0, 0.4.0.0 (conflict: gtk2hs-hello
=> transformers>=0.3.0.0 && <0.4)
Dependency tree exhaustively searched.