Resolving dependencies... cabal: Could not resolve dependencies: next goal: hailgun-send (user goal) rejecting: hailgun-send-0.1.1.1, hailgun-send-0.1.1.0 (constraint from user target requires ==0.1.0.0) trying: hailgun-send-0.1.0.0 next goal: base (dependency of hailgun-send-0.1.0.0) rejecting: base-4.9.0.0/installed-4.9... (conflict: hailgun-send => base>=4.6 && <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.