I've just tested this, and with GHC 7, cabal chooses QuickCheck 2.4,
whereas with GHC 6.12, it chooses 2.1. If I specify that 6.12 should
choose 2.4 as well, I get the same issue there. This is to be
expected, because I don't see the CPP checks you mentioned in
Test/QuickCheck/Instances.hs in testpack-2.0.1. Perhaps you haven't
released a version with those checks yet?
Erik
On Thu, Mar 24, 2011 at 14:18, John Goerzen
Hi folks,
I don't have a GHC 7 environment running yet (it's on my list...) but I received a bug report pointing me at this build failure:
http://hackage.haskell.org/packages/archive/testpack/2.0.1/logs/failure/ghc-...
Among other things, this noted:
Dependency QuickCheck >=2.1.0.3: using QuickCheck-2.4.0.1
and the errors were:
[1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist/build/Test/QuickCheck/Instances.o )
src/Test/QuickCheck/Instances.hs:39:10: Duplicate instance declarations: instance Arbitrary Word8 -- Defined at src/Test/QuickCheck/Instances.hs:39:10-24 instance Arbitrary Word8 -- Defined in Test.QuickCheck.Arbitrary
src/Test/QuickCheck/Instances.hs:42:10: Duplicate instance declarations: instance CoArbitrary Word8 -- Defined at src/Test/QuickCheck/Instances.hs:42:10-26 instance CoArbitrary Word8 -- Defined in Test.QuickCheck.Arbitrary
Now, that's fairly standard, and in fact, in my code, is wrapped with:
#if MIN_VERSION_QuickCheck(2,3,0) -- we have Word8 instances here #else instance Arbitrary Word8 where arbitrary = sized $ \n -> choose (0, min (fromIntegral n) maxBound)
instance CoArbitrary Word8 where coarbitrary n = variant (if n >= 0 then 2 * x else 2 * x + 1) where x = abs . fromIntegral $ n #endif
And that code has been working to support modern QuickCheck versions for some time.
It would appear that something in Cabal, GHC 7, or QuickCheck is breaking this check.
Ideas?
-- John
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