#> emerge -1 =haddock-2.10.0 =cabal-1.14.0
Calculating dependencies... done!
[ebuild   R    ] dev-haskell/cabal-1.14.0
[ebuild     U #] dev-haskell/haddock-2.10.0 [2.9.2]

The following mask changes are necessary to proceed:
#required by =haddock-2.10.0 (argument)
# /home/.../overlay/gentoo-haskell/profiles/package.mask:
# Sergei Trofimovich <[email protected]> (21 Jul 2010)
# The experimental branch.
=dev-haskell/haddock-2.10.0

NOTE: The --autounmask-keep-masks option will prevent emerge
      from creating package.unmask or ** keyword changes.

Use --autounmask-write to write changes to config files (honoring CONFIG_PROTECT).