Resolving dependencies... cabal: Could not resolve dependencies: next goal: levmar (user goal) rejecting: levmar-1.2.1.6, levmar-1.2.1.5, levmar-1.2.1.4, levmar-1.2.1.3, levmar-1.2.1.2, levmar-1.2.1.1, levmar-1.2.1, levmar-1.2.0.1, levmar-1.2, levmar-1.1.0.1, levmar-1.1, levmar-1.0, levmar-0.3, levmar-0.2.1 (constraint from user target requires ==0.2) trying: levmar-0.2 next goal: base (dependency of levmar-0.2) rejecting: base-4.9.0.0/installed-4.9... (conflict: levmar => base>=3 && <4.2) 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.