Oh, that makes sense. If you regularly do stuff with OverlappingInstances,
... which you wouldn't, at a basic level? Rather than split off a whole set of basic categories like - basic Haskell - really basic Haskell - really, really basic Haskell ... it makes sense to me to distinguish "basic" from "what we use all the time at our shop." Basic would be, as Johan Larson proposed, the things you'd really need to write in Haskell, with fundamental properties of the language that contribute to reusability, type safety etc. We could reasonably put type classes at that level, for example, if for no other reason than it's hard to make any sense out of the platform libraries without knowing about classes and instances etc. But language features that aren't even supported by default? Is that even Haskell, as opposed to GHC? Donn