[Haskell-beginners] `coarbitrary' is not a (visible) method of class `Arbitrary'

Amy de Buitléir amy at nualeargais.ie
Sat Dec 19 09:30:10 EST 2009

Thank you Daniel, that solved it. In case anyone else is struggling
with this, here's a revised version of Test.hs which works fine for

import Char
import List
import Test.QuickCheck
import Text.Printf

main  = mapM_ (\(s,a) -> printf "%-25s: " s >> a) tests

-- reversing twice a finite list, is the same as identity
prop_reversereverse s = (reverse . reverse) s == id s
    where _ = s :: [Int]

-- and add this to the tests list
tests  = [("reverse.reverse/id", quickCheck prop_reversereverse)]

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