Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: DAV (user goal)
rejecting: DAV-1.3.1, DAV-1.3, DAV-1.2, DAV-1.1, DAV-1.0.7, DAV-1.0.6,
DAV-1.0.5 (constraint from user target requires ==1.0.4)
trying: DAV-1.0.4
next goal: base (dependency of DAV-1.0.4)
rejecting: base-4.9.0.0/installed-4.9... (conflict: DAV => base>=4.5 && <4.8)
rejecting: base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0,
base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0,
base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0,
base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0,
base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable
package requires installed instance)
Dependency tree exhaustively searched.