rapid_check_overflow_detection.hs

instance Arbitrary Int where
  arbitrary = Gen $ \rand -> fst (next rand)

prop_gcd_overflow :: Int -> Int -> Bool
prop_gcd_overflow a b = a * b == gcd a b * lcm a b

rapidCheck prop_gcd_overflow
> Failure {seed = -881134321,
           counterExample = ["171542757","1235104953"]}