https://bugzilla.redhat.com/show_bug.cgi?id=1093622
--- Comment #5 from Benjamin b@stbe.at --- (c) is fine for me, since I've still 3.0.5 installed and can simply ignore the update of alex.
I'm not sure if both versions can be in the repos, then haskell-platform could still be installed in a clean way. Else (b) would make more sense to me - since rebuilding all dependencies (I assume this is (a)) will be more work to do?