Simon Marlow wrote:
Brian Hulley wrote:
Hi - I have the following code:
[snip]
Is this just a bug in Haddock or am I misunderstanding something about Haskell?
It's a bug / missing feature in Haddock. Haddock is basically pretty dumb when it comes to understanding Haskell code; it knows about the syntax and the module system, and that's about all. It makes a half-hearted attempt to figure out what instances you get from deriving clauses, but it's not complete, and you've encountered a case it doesn't handle.
One day Haddock will be built on top of the GHC API, and all this will be fixed...
Thanks - I'm glad it's not just me! In the meantime, I found a better workaround (since the type decl using a class name is not legal Haskell) is just to use -cpp to preprocess for both ghc and haddock so that haddock sees explicitly defined dummy instances instead of a newtype deriving clause, then perfect results are obtained... :-) Regards, Brian.