Re: [Haskell] Empty instance declaration

Neil Mitchell wrote:

If the default methods form a cycle, and the user has not broken that cycle by inserting a real implementation, that's almost certainly a bug - I'd go as far as to say its an error rather than a warning.

I'd agree except that "instance Num () where" with no specified definitions is already allowed in Haskell and can only generate warnings in GHC already. Isaac