Upgrading ghc to 7.0.3 breaks wai-handler-devel

I'm developing a web app on Yesod framework, using wai-handler-devel to run the server.

A pacman -Syu (on Arch Linux) upgraded ghc from 7.0.2 to 7.0.3 and now the server throws an exception.

$ wai-handler-devel 3000 App.Controller withAppSimple
Attempting to interpret your app...
wai-handler-devel: /usr/lib/ghc-7.0.2/package.conf.d/package.cache:
openBinaryFile: does not exist (No such file or directory)

After a bit of digging I realized that the file existed in /usr/lib/ghc-7.0.3/package.conf.d/, so I renamed that folder to ghc-7.0.3 in the hopes that that would at least temporarily sol开发者_JAVA技巧ve the problem (until our Haskell-guy comes back from holiday).

Any suggestion on where to even begin would be very helpful. Thanks!

you need to re-install all your packages when you upgrade a ghc version (not just wai-handler-devel). You may as well delete all the old ones.