At 2001-09-29 09:11, Mike Gunter wrote:

class Add a b c where add :: a -> b -> c

There does not seem to be a way to do everything I'd like in GHC even in its most permissive mode (I'm using "-fallow-overlapping-instances -fallow-undecidable-instances".) In particular, I'd like to use bare

You know about fundeps, right? This may help: class Add a b c | a b -> c where {add :: a -> b -> c;}; -- Ashley Yakeley, Seattle WA