Oddity with 'cabal install' in GHC 7.4.1

[Andres Löh]

>> I've been
>> unable to avoid this error message by any other means that (a) 'ghc-pkg
>> unregister <package>' or (b) '--force-reinstall'. So far, '--solver=modular'
>> hasn't helped. So I'm hoping for something less aggressive. In particular,
>> in case nothing has changed, I want 'cabal install' to succeed (exit code 0)
>> so that my automated build & install & release processes will continue
>> rather than get stopped.
>
> The message appears, but building should work, with --force-reinstall
> and no --dry-run. Can you confirm that you've tried that?

Actually, the message should not even appear if --force-reinstalls is
given. Are you using the latest development version of cabal-install
from darcs?

Cheers,
  Andres