Resolving dependencies... cabal: Could not resolve dependencies: next goal: system-fileio (user goal) rejecting: system-fileio-0.3.16.3, 0.3.16.2, 0.3.16.1, 0.3.16, 0.3.15, 0.3.14, 0.3.13, 0.3.12, 0.3.11, 0.3.10, 0.3.9, 0.3.8, 0.3.7, 0.3.6, 0.3.5, 0.3.4, 0.3.3, 0.3.2.1, 0.3.2, 0.3.1, 0.3, 0.2.7, 0.2.6, 0.2.5 (global constraint requires ==0.2.4) trying: system-fileio-0.2.4 trying: base-4.8.1.0/installed-4f7... (dependency of system-fileio-0.2.4) next goal: unix (dependency of system-fileio-0.2.4) rejecting: unix-2.7.1.0/installed-643..., 2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1, 2.6.0.0 (conflict: system-fileio => unix>=2.3 && <2.6) rejecting: unix-2.5.1.1, 2.5.1.0 (conflict: base==4.8.1.0/installed-4f7..., unix => base>=4.5 && <4.6) rejecting: unix-2.5.0.0 (conflict: base==4.8.1.0/installed-4f7..., unix => base>=4.2 && <4.5) rejecting: unix-2.4.2.0, 2.4.1.0 (conflict: base==4.8.1.0/installed-4f7..., unix => base>=4.2 && <4.4) rejecting: unix-2.4.0.2, 2.4.0.1 (conflict: base==4.8.1.0/installed-4f7..., unix => base>=4.2 && <4.3) rejecting: unix-2.4.0.0 (conflict: base==4.8.1.0/installed-4f7..., unix => base>=4.1 && <4.3) rejecting: unix-2.3.2.0, 2.3.1.0, 2.3.0.0 (conflict: base==4.8.1.0/installed-4f7..., unix => base<4.3) rejecting: unix-2.2.0.0, 2.0 (conflict: system-fileio => unix>=2.3 && <2.6) Dependency tree exhaustively searched.