when reporting missing modules, report them all at once
Currently, when a module is missing I get the message:
Main.hs:6:18: Could not find module `Data.StorableVector.Base' It is a member of the hidden package `storablevector-0.2.8'. Perhaps you need to add `storablevector' to the build-depends in your .cabal file. It is a member of the hidden package `storablevector-0.2.8.1'. Perhaps you need to add `storablevector' to the build-depends in your .cabal file. Use -v to see a list of the files searched for.
In order to solve the problem I add the package name to the Cabal file as suggested. However, if many modules are missing, then it becomes tedious to add every package individually and recompile with Cabal. It would be great if GHC shows all missing modules and their according packages. This helps a lot when converting from the old Cabal style "recompile all library modules for an executable" to the new style "import the main library for every executable".