I've just installed GHC 8.0.1, and it seems that my QuickCheck is now broken. I'm presuming that these two facts are connected.

I have a trivially small QuickCheck example:

> import Test.QuickCheck
> prop_PlusAssociative :: Integer -> Integer -> Integer -> Bool
> prop_PlusAssociative x y z = (x+y)+z == x+(y+z)

This loads fine, but when I try to test the property I get a mysterious error:

jg$ ghci quickcheck.lhs
GHCi, version 7.10.2: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( quickcheck.lhs, interpreted )
Ok, modules loaded: Main.
*Main> quickCheck prop_PlusAssociative 
can't load .so/.DLL for: /Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib (dlopen(/Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib, 5): Library not loaded: @rpath/libHSrandom-1.1-1z8Ujelqc6aKgvPnbRUKkP-ghc7.10.2.dylib
  Referenced from: /Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib
  Reason: image not found)

I don't think it's anything to do with QuickCheck itself; I get the same error just trying to use the System.Random.TF library directly:

jg$ ghci
GHCi, version 7.10.2: http://www.haskell.org/ghc/  :? for help
Prelude> import System.Random.TF.Gen
Prelude System.Random.TF.Gen> seedTFGen (1,1,1,1)
can't load .so/.DLL for: /Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib (dlopen(/Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib, 5): Library not loaded: @rpath/libHSrandom-1.1-1z8Ujelqc6aKgvPnbRUKkP-ghc7.10.2.dylib
  Referenced from: /Library/Haskell/ghc-7.10.2-x86_64/lib/tf-random-0.5/libHStf-random-0.5-926BwEbiHzi7pBkp4dTxOe-ghc7.10.2.dylib
  Reason: image not found)

The "7.10.2" is because I deactivated 8.0.1, then installed 7.10.3, then uninstalled both, then uninstalled all GHCs and deleted /Library/Haskell and reinstalled GHC 7.10.2 (my last working version) from what I hoped would be a clean slate. All to no avail. However, I do appear still to have a ghc-7.4.2, overlooked by uninstall-hs; and that does work fine - apparently not using the same System.Random.TF library.

Can anyone suggest what I'm doing wrong, and more importantly, how to fix it?

Jeremy

Jeremy.Gibbons@cs.ox.ac.uk
Oxford University Department of Computer Science,
Wolfson Building, Parks Road, Oxford OX1 3QD, UK.
+44 1865 283521
http://www.cs.ox.ac.uk/people/jeremy.gibbons/