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/