Simo (and others who work on Haskell packages),

Currently, every even minor ghc update breaks all packages that are registered via Cabal. This is not because of API incompatibilities but because the new version of ghc overwrites the Cabal db. This can be manually fixed by running all /usr/share/haskell/*/register.sh.

I was wondering... could ghc do that itself in post_upgrade()?