Add instance of Arbitrary for Vector.

Author: jonathanknowles

src/test/ClassSpec.hs

@@ -89,13 +89,12 @@ import Test.QuickCheck.Classes.Semigroup.Cancellative
     )
 import Test.QuickCheck.Classes.Semigroup.Factorial
     ( factorialLaws, stableFactorialLaws )
-import Test.QuickCheck.Instances.Vector
-    ()
 import Test.QuickCheck.Property
     ( Result (..), mapTotalResult )
 
 import qualified Data.ByteString.Lazy as ByteString
 import qualified Data.Text as Text
+import qualified Data.Vector as Vector
 
 spec :: Spec
 spec = do
@@ -591,6 +590,10 @@ instance Arbitrary Natural where
     arbitrary = elements [0 .. 3]
     shrink = shrinkIntegral
 
+instance Arbitrary a => Arbitrary (Vector a) where
+    arbitrary = Vector.fromList <$> arbitrary
+    shrink = shrinkMap Vector.fromList Vector.toList
+
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