Hi, Simon's recent changes to the package system have the effect that cabal-built packages cannot be used. Example error (from lambdabot, using fps that was previously built using cabal): scripts/BotPP.hs:20:0: Failed to load interface for `Data.ByteString.Char8': Bad interface file: /opt/ghc/lib/fps-0.7/ghc-6.5/Data/ByteString/Char8.hi Something is amiss; requested module fps-0.7:Data.ByteString.Char8 differs from name found in the interface file fps:Data.ByteString.Char8 The attached patch fixes this in Cabal by passing the full package name (including version) to the -package-name option. I expect that it breaks on older ghc versions, and thus should not be applied to the official darcs repository. But I hope it's still useful for someone while the underlying issue is resolved. (Maybe ghc shouldn't be unhappy about this in the first place?) regards, Bertram