Thanks, Philipp. Worked for me as well. For others with the same symptoms,
here's the incantation I used:
sudo cabal install --reinstall --force-reinstalls --enable-documentation
--global random-1.0.1.1
And similarly for all of the other pre-installed packages. I reversed the
order listed by
Since installing GHC 7.4.1 (from sources), I'm getting lots of complaints
from 'ghc-pkg check', of the following form:
Warning: haddock-interfaces:
/usr/local/share/doc/transformers-0.2.2.0/html/transformers.haddock doesn't
exist or isn't a file
Warning: haddock-html:
