Deal with breaking change in QuickCheck

Author: MaximilianAlgehed

src/Constrained/Core.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ImportQualifiedPost #-}
@@ -35,11 +36,15 @@ import Constrained.PrettyUtils
 import Control.Applicative
 import Data.Function
 import Data.List.NonEmpty (NonEmpty ((:|)))
-import Data.List.NonEmpty qualified as NE
 import Data.Set (Set)
 import Data.Set qualified as Set
 import Data.Typeable
+
+-- Orphan instance for old QuickCheck versions
+#if !MIN_VERSION_QuickCheck(2, 17, 0)
+import Data.List.NonEmpty qualified as NE
 import Test.QuickCheck (Arbitrary (..), NonEmptyList (NonEmpty))
+#endif
 
 -- Variables --------------------------------------------------------------
 
@@ -135,7 +140,9 @@ instance Typeable c => Show (Evidence c) where
 unionWithMaybe :: (a -> a -> a) -> Maybe a -> Maybe a -> Maybe a
 unionWithMaybe f ma ma' = (f <$> ma <*> ma') <|> ma <|> ma'
 
+#if !MIN_VERSION_QuickCheck(2, 17, 0)
 instance Arbitrary a => Arbitrary (NonEmpty a) where
   arbitrary = do
     NonEmpty xs <- arbitrary
     pure (NE.fromList xs)
+#endif

src/Constrained/NumOrd.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE AllowAmbiguousTypes #-}
 {-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DefaultSignatures #-}
 {-# LANGUAGE DerivingVia #-}
@@ -257,9 +258,11 @@ instance (Arbitrary a, Ord a) => Arbitrary (NumSpec a) where
   shrink (NumSpecInterval m m') =
     uncurry NumSpecInterval <$> shrink (m, m')
 
+#if !MIN_VERSION_QuickCheck(2, 17, 0)
 instance Arbitrary Natural where
   arbitrary = wordToNatural . abs <$> arbitrary
   shrink n = [wordToNatural w | w <- shrink (naturalToWord n)]
+#endif
 
 instance Uniform Natural where
   uniformM g = wordToNatural . abs <$> uniformM g