Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: sizes (user goal)
rejecting: sizes-2.3.2, 2.3.1.1, 2.3.1, 2.3.0, 2.1.3, 2.1.2, 2.1.1, 2.1.0,
2.0.7, 2.0.6, 2.0.5, 2.0.4, 2.0.3, 2.0.2 (global constraint requires ==2.0.1)
trying: sizes-2.0.1
trying: base-4.8.1.0/installed-4f7... (dependency of sizes-2.0.1)
next goal: unix (dependency of sizes-2.0.1)
rejecting: unix-2.7.1.0/installed-643..., 2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1
(conflict: sizes => unix==2.6.0.0)
rejecting: unix-2.6.0.0 (conflict: base==4.8.1.0/installed-4f7..., unix =>
base>=4.5 && <4.7)
rejecting: unix-2.5.1.1, 2.5.1.0, 2.5.0.0, 2.4.2.0, 2.4.1.0, 2.4.0.2, 2.4.0.1,
2.4.0.0, 2.3.2.0, 2.3.1.0, 2.3.0.0, 2.2.0.0, 2.0 (conflict: sizes =>
unix==2.6.0.0)
Dependency tree exhaustively searched.