Resolving dependencies... cabal: Could not resolve dependencies: next goal: esqueleto (user goal) rejecting: esqueleto-2.4.1, 2.4.0, 2.3.0, 2.2.12, 2.2.11, 2.2.10, 2.2.9, 2.2.8, 2.2.7, 2.2.6, 2.2.5, 2.2.4, 2.2.3, 2.2.2, 2.2.1, 2.2, 2.1.3, 2.1.2.3, 2.1.2.2, 2.1.2.1, 2.1.2, 2.1.1, 2.1.0, 2.0.3, 2.0.2, 2.0.1, 2.0.0, 1.4.4, 1.4.3, 1.4.2, 1.4.1.3, 1.4.1.2, 1.4.1, 1.4, 1.3.12, 1.3.11, 1.3.10, 1.3.9, 1.3.8, 1.3.7, 1.3.6, 1.3.5, 1.3.4.6, 1.3.4.5, 1.3.4.4, 1.3.4.3, 1.3.4.2, 1.3.4, 1.3.3, 1.3.2, 1.3.1 (global constraint requires ==1.3) trying: esqueleto-1.3 next goal: base (dependency of esqueleto-1.3) rejecting: base-4.8.1.0/installed-4f7... (conflict: esqueleto => base>=4.5 && <4.7) rejecting: base-4.8.1.0, 4.8.0.0, 4.7.0.2, 4.7.0.1, 4.7.0.0, 4.6.0.1, 4.6.0.0, 4.5.1.0, 4.5.0.0, 4.4.1.0, 4.4.0.0, 4.3.1.0, 4.3.0.0, 4.2.0.2, 4.2.0.1, 4.2.0.0, 4.1.0.0, 4.0.0.0, 3.0.3.2, 3.0.3.1 (global constraint requires installed instance) Dependency tree exhaustively searched.