ANNOUNCE: GHC 6.8.3 Release Candidate

Ian Lynagh igloo at
Sun Jun 1 10:34:00 EDT 2008

On Sun, Jun 01, 2008 at 05:39:49PM +0400, Serge D. Mechveliani wrote:
> This is why  res  and  1*res  are not equivalent in Haskell-98 for  
> res :: Num a => a.
> Am I missing something?

The library functions assume that class instances obey some unwritten
laws; it's all a bit vague, but if your instances don't obey them then
you might find that things go wrong when using library functions. For
example, if your (*) isn't associative then (^) is going to give odd
results, and if the type of the second argument to (^) doesn't do
arithmetic in the normal way then very strange things could happen.

Anyway, I've just tweaked the (^) definition again, so your code should
work in 6.8.3.


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