Resolving dependencies... cabal: Could not resolve dependencies: next goal: GeBoP (user goal) rejecting: GeBoP-1.7.5, GeBoP-1.7.4.1, GeBoP-1.7.4 (constraint from user target requires ==1.7.3) trying: GeBoP-1.7.3 next goal: base (dependency of GeBoP-1.7.3) rejecting: base-4.9.0.0/installed-4.9... (conflict: GeBoP => base>=4.5 && <4.7) rejecting: base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable package requires installed instance) Dependency tree exhaustively searched.