Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: hdocs (user goal)
rejecting: hdocs-0.4.2.1 (global constraint requires ==0.4.2.0)
trying: hdocs-0.4.2.0
trying: haddock-api-2.16.0 (dependency of hdocs-0.4.2.0)
next goal: ghc (dependency of hdocs-0.4.2.0)
rejecting: ghc-7.8.3/installed-4df... (conflict: haddock-api => ghc>=7.10 &&
<7.10.2)
Dependency tree exhaustively searched.