Resolving dependencies... cabal: Could not resolve dependencies: next goal: gtk3 (user goal) 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, 0.12.5.7, 0.12.5.6, 0.12.5.5, 0.12.5.4, 0.12.5.3, 0.12.5.2 (global constraint requires ==0.12.5.1) rejecting: gtk3-0.12.5.1 (conflict: gtk3 => gtk3==0.12.5.0) rejecting: gtk3-0.12.5.0 (global constraint requires ==0.12.5.1) Dependency tree exhaustively searched.