Resolving dependencies...
cabal: Could not resolve dependencies:
trying: cabal-install-ghc74-0.10.4 (user goal)
trying: base-4.7.0.1/installed-e4b... (dependency of
cabal-install-ghc74-0.10.4)
next goal: unix (dependency of cabal-install-ghc74-0.10.4)
rejecting: unix-2.7.0.1/installed-0d8..., 2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1,
2.6.0.0 (conflict: cabal-install-ghc74 => unix>=1.0 && <2.6)
rejecting: unix-2.5.1.1, 2.5.1.0 (conflict: base==4.7.0.1/installed-e4b...,
unix => base>=4.5 && <4.6)
rejecting: unix-2.5.0.0 (conflict: base==4.7.0.1/installed-e4b..., unix =>
base>=4.2 && <4.5)
rejecting: unix-2.4.2.0, 2.4.1.0 (conflict: base==4.7.0.1/installed-e4b...,
unix => base>=4.2 && <4.4)
rejecting: unix-2.4.0.2, 2.4.0.1 (conflict: base==4.7.0.1/installed-e4b...,
unix => base>=4.2 && <4.3)
rejecting: unix-2.4.0.0 (conflict: base==4.7.0.1/installed-e4b..., unix =>
base>=4.1 && <4.3)
rejecting: unix-2.3.2.0, 2.3.1.0, 2.3.0.0, 2.2.0.0, 2.0 (conflict:
base==4.7.0.1/installed-e4b..., unix => base<4.3)
Dependency tree exhaustively searched.