Ah, I've figured it out. The new .hi-boot file format is actually Haskell!! Well almost. You have to fully qualify type names (you can't use Int, you must use GHC.Base.Int) and the input isn't run through -cpp.

Yes, that's the idea. Now that we don't have an interface file parser as such, .hi-boot parsing is done by the main parser with the result that the syntax is much more Haskellish (and hence more readable). We wondered about various schemes to make the recursive module story easier, but couldn't come up with anything that was worth the effort to implement - "doing it properly" i.e. reading the Haskell source to get the type signatures and data declarations, or even allowing unqualified names in the .hi-boot file is a total swamp. Hope the new .hi-boot syntax doesn't cause you too much hassle... Cheers, Simon