Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: cabal-dev (user goal)
rejecting: cabal-dev-0.9.2, 0.9.1, 0.9, 0.8, 0.7.4.1, 0.7.4.0, 0.7.3.2,
0.7.3.1, 0.7.2.1, 0.7.2, 0.7.1 (global constraint requires ==0.7)
trying: cabal-dev-0.7
trying: base-4.8.1.0/installed-4f7... (dependency of cabal-dev-0.7)
trying: cabal-dev-0.7:-no-cabal-dev
next goal: tar (dependency of cabal-dev-0.7:-no-cabal-dev)
rejecting: tar-0.4.2.2, 0.4.2.1, 0.4.2.0, 0.4.1.0, 0.4.0.1, 0.4.0.0 (conflict:
cabal-dev-0.7:no-cabal-dev => tar>=0.3 && <0.4)
rejecting: tar-0.3.2.0 (conflict: base==4.8.1.0/installed-4f7..., tar =>
base>=3 && <4.8)
rejecting: tar-0.3.1.0, 0.3.0.0 (conflict: base==4.8.1.0/installed-4f7..., tar
=> base>=2 && <4.5)
rejecting: tar-0.1.1.3, 0.1.1.1, 0.1.1, 0.1 (conflict:
cabal-dev-0.7:no-cabal-dev => tar>=0.3 && <0.4)
Dependency tree exhaustively searched.