Am 05.01.2012 19:14 schrieb "Brandon Allbery" <allbery.b@gmail.com>:
>> What I don't get is how a new instance may break existing code. Any example? 
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> It's not unusual for people to define their own instances for things; if a new release of the library then adds its own version of those instances, even if they are identical, then those people's code will break.  Google "orphan instances" to see both general and concrete discussion of the problem.
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> I'm blanking on recent practical examples, but there have been some.

I see. No examples needed - I just had to do that myself in benchmark code, because FingerTree does not instance NFData. When it does, my code will break. Got that.

Thanks,
Chris