Resolving dependencies...
cabal: Could not resolve dependencies:
trying: cabal-install-ghc74-0.10.4 (user goal)
trying: base-4.9.0.0/installed-4.9... (dependency of
cabal-install-ghc74-0.10.4)
next goal: unix (dependency of cabal-install-ghc74-0.10.4)
rejecting: unix-2.7.2.0/installed-2.7..., unix-2.7.2.0, unix-2.7.1.0,
unix-2.7.0.1, unix-2.7.0.0, unix-2.6.0.1, unix-2.6.0.0 (conflict:
cabal-install-ghc74 => unix>=1.0 && <2.6)
rejecting: unix-2.5.1.1, unix-2.5.1.0 (conflict:
base==4.9.0.0/installed-4.9..., unix => base>=4.5 && <4.6)
rejecting: unix-2.5.0.0 (conflict: base==4.9.0.0/installed-4.9..., unix =>
base>=4.2 && <4.5)
rejecting: unix-2.4.2.0, unix-2.4.1.0 (conflict:
base==4.9.0.0/installed-4.9..., unix => base>=4.2 && <4.4)
rejecting: unix-2.4.0.2, unix-2.4.0.1 (conflict:
base==4.9.0.0/installed-4.9..., unix => base>=4.2 && <4.3)
rejecting: unix-2.4.0.0 (conflict: base==4.9.0.0/installed-4.9..., unix =>
base>=4.1 && <4.3)
rejecting: unix-2.3.2.0, unix-2.3.1.0, unix-2.3.0.0, unix-2.2.0.0, unix-2.0
(conflict: base==4.9.0.0/installed-4.9..., unix => base<4.3)
Dependency tree exhaustively searched.