Adam Gundry
writes: I've started to document the plan on the GHC wiki:
http://hackage.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/Pla n
Thank you Adam, (Simon) I like the approach for Representation hiding. (That was something I was particularly trying to preserve out of H98 records.) At first I was worried this would involve 'scoped' instances -- which seems a wild departure. But I see in the 'Multiple modules' section that you're generating instances on-the-fly. So I agree that option (2) looks best. As I understand it, this means that the extensions switched on in the importing module is all we have to worry about, not what extensions applied where the data type is declared. So for backward compatibility, I can import historic Library L ( R(x) ) which knows nothing about the new stuff. And in my module (with the extension on) declare data type T with field x, and not have a clash of field names. Sweet!