I need some help! I did someone a good deed on a blog the other day, so I'm swallowing my pride and asking for a random kind deed from someone who knows something.

While trying to compile this snippet, I get this compilation error - a complaint about a missing instance.

This occurs with:

• GHC 6.8.2
• Various packages installed system wide (ubuntu 8.04 packages) and locally (using cabal --user --prefix=$HOME/local)
• bytestring-0.9.0.2 or anything later

If I revert to the bytestring that comes with my system, 0.9.0.1 , the error goes away. Having finally looked at the differences between 0.9.0.1 and 0.9.0.2, which are tiny, and do not include any differences when it comes to the definition of typeclass instances, it seems clear that this isn't really the problem, but something else very funny is going on. But I do not have the first what.

I was just coping with it by sticking with bytestring-0.9.0.1, but I won't be able to do that forever...

Do I have to rebuild all the packages in my system or something evil? Any ideas?

Thanks in advance!