[Haskell-cafe] Bug with QuickCheck 1.1 and GHC 6.8.2

[Patrick Perry]

The bug is in the "variant" function in QuickCheck.  I replaced

variant :: Int -> Gen a -> Gen a
variant v (Gen m) = Gen (\n r -> m n (rands r !! (v+1))
  where
   rands r0 = r1 : rands r2 where (r1, r2) = split r0

with

variant :: Int -> Gen a -> Gen a
variant v (Gen m) = Gen (\n r -> m n (rands r !! v'))
  where
   v' = abs (v+1) `mod` 10000
   rands r0 = r1 : rands r2 where (r1, r2) = split r0

and now everything works fine.  "10000" seems like a reasonable value  
here, but one could hard-code a lower or higher value as well.

Can someone make sure this gets fixed in the next version of  
QuickCheck?  I'm not sure who the maintainer is.


Patrick