Remove unused imports, dead code, and unused deps

The test suite dependency on ghc-prim has been removed.
An import of Data.Ord in the test suite has been removed.
All shims for GHC 8.0 have been removed.

Data/Primitive/Array.hs

@@ -52,9 +52,6 @@ import qualified GHC.ST as GHCST
 import qualified Data.Foldable as F
 import Data.Semigroup
 import Data.Functor.Identity
-#if !MIN_VERSION_base(4,10,0)
-import GHC.Base (runRW#)
-#endif
 
 import Text.Read (Read (..), parens, prec)
 import Text.ParserCombinators.ReadPrec (ReadPrec)
@@ -799,14 +796,7 @@ instance Read a => Read (Array a) where
 
 -- | @since 0.6.4.0
 instance Read1 Array where
-#if MIN_VERSION_base(4,10,0)
   liftReadPrec = arrayLiftReadPrec
-#else
-  -- This is just the default implementation of liftReadsPrec, but
-  -- it is not present in older versions of base.
-  liftReadsPrec rp rl = RdPrc.readPrec_to_S $
-    arrayLiftReadPrec (RdPrc.readS_to_Prec rp) (RdPrc.readS_to_Prec (const rl))
-#endif
 
 -- Note [Forgiving Array Read Instance]
 -- We're really forgiving here. We accept

Data/Primitive/ByteArray.hs

@@ -75,9 +75,7 @@ import Control.Monad.ST
 import Data.Primitive.Types
 import Data.Proxy
 
-#if MIN_VERSION_base(4,10,0)
 import qualified GHC.ST as GHCST
-#endif
 
 import Data.Word ( Word8 )
 #if __GLASGOW_HASKELL__ >= 802
@@ -640,7 +638,6 @@ cloneMutableByteArray src off n = do
 runByteArray
   :: (forall s. ST s (MutableByteArray s))
   -> ByteArray
-#if MIN_VERSION_base(4,10,0) /* In new GHCs, runRW# is available. */
 runByteArray m = ByteArray (runByteArray# m)
 
 runByteArray#
@@ -652,9 +649,6 @@ runByteArray# m = case runRW# $ \s ->
 
 unST :: ST s a -> State# s -> (# State# s, a #)
 unST (GHCST.ST f) = f
-#else /* In older GHCs, runRW# is not available. */
-runByteArray m = runST $ m >>= unsafeFreezeByteArray
-#endif
 
 -- Create an uninitialized array of the given size in bytes, apply the function
 -- to it, and freeze the result.

Data/Primitive/PrimArray.hs

@@ -125,9 +125,7 @@ import Control.Monad.ST
 import qualified Data.List as L
 import qualified Data.Primitive.ByteArray as PB
 import qualified Data.Primitive.Types as PT
-#if MIN_VERSION_base(4,10,0)
 import qualified GHC.ST as GHCST
-#endif
 import Language.Haskell.TH.Syntax (Lift (..))
 
 import Data.Semigroup
@@ -1144,7 +1142,6 @@ cloneMutablePrimArray src off n = do
 runPrimArray
   :: (forall s. ST s (MutablePrimArray s a))
   -> PrimArray a
-#if MIN_VERSION_base(4,10,0) /* In new GHCs, runRW# is available. */
 runPrimArray m = PrimArray (runPrimArray# m)
 
 runPrimArray#
@@ -1156,9 +1153,6 @@ runPrimArray# m = case runRW# $ \s ->
 
 unST :: ST s a -> State# s -> (# State# s, a #)
 unST (GHCST.ST f) = f
-#else /* In older GHCs, runRW# is not available. */
-runPrimArray m = runST $ m >>= unsafeFreezePrimArray
-#endif
 
 -- | Create an uninitialized array of the given length, apply the function to
 -- it, and freeze the result.

Data/Primitive/SmallArray.hs

@@ -88,9 +88,6 @@ import Data.Semigroup
 import Text.ParserCombinators.ReadP
 import Text.ParserCombinators.ReadPrec (ReadPrec)
 import qualified Text.ParserCombinators.ReadPrec as RdPrc
-#if !MIN_VERSION_base(4,10,0)
-import GHC.Base (runRW#)
-#endif
 
 import Data.Functor.Classes (Eq1(..), Ord1(..), Show1(..), Read1(..))
 import Language.Haskell.TH.Syntax (Lift(..))
@@ -892,14 +889,7 @@ instance Read a => Read (SmallArray a) where
 
 -- | @since 0.6.4.0
 instance Read1 SmallArray where
-#if MIN_VERSION_base(4,10,0)
   liftReadPrec = smallArrayLiftReadPrec
-#else
-  -- This is just the default implementation of liftReadsPrec, but
-  -- it is not present in older versions of base.
-  liftReadsPrec rp rl = RdPrc.readPrec_to_S $
-    smallArrayLiftReadPrec (RdPrc.readS_to_Prec rp) (RdPrc.readS_to_Prec (const rl))
-#endif
 
 smallArrayDataType :: DataType
 smallArrayDataType =

Data/Primitive/Types.hs

@@ -410,9 +410,7 @@ deriving instance Prim CWchar
 deriving instance Prim CSigAtomic
 deriving instance Prim CLLong
 deriving instance Prim CULLong
-#if MIN_VERSION_base(4,10,0)
 deriving instance Prim CBool
-#endif
 deriving instance Prim CIntPtr
 deriving instance Prim CUIntPtr
 deriving instance Prim CIntMax

primitive.cabal

@@ -87,7 +87,6 @@ test-suite test-qc
   type: exitcode-stdio-1.0
   build-depends: base
                , base-orphans
-               , ghc-prim
                , primitive
                , quickcheck-classes-base >= 0.6 && <0.7
                , QuickCheck >= 2.13 && < 2.16

test/Main.hs

@@ -32,7 +32,6 @@ import PrimLaws (primLaws)
 
 import Data.Functor.Identity (Identity(..))
 import qualified Data.Monoid as Monoid
-import Data.Ord (Down(..))
 import Data.Semigroup (stimes, stimesMonoid)
 import qualified Data.Semigroup as Semigroup
 #if !(MIN_VERSION_base(4,11,0))