Drop support of GHC < 8 (#336)

* Support only GHC >= 8.0

* Fix a build warning

* Make integer-simple flag redundant

Author: Bodigrim

.github/workflows/haskell-ci.yml

@@ -44,18 +44,6 @@ jobs:
             allow-failure: false
           - compiler: ghc-8.0.2
             allow-failure: false
-          - compiler: ghc-7.10.3
-            allow-failure: false
-          - compiler: ghc-7.8.4
-            allow-failure: false
-          - compiler: ghc-7.6.3
-            allow-failure: false
-          - compiler: ghc-7.4.2
-            allow-failure: false
-          - compiler: ghc-7.2.2
-            allow-failure: false
-          - compiler: ghc-7.0.4
-            allow-failure: false
       fail-fast: false
     steps:
       - name: apt

benchmarks/haskell/Benchmarks/Builder.hs

@@ -12,9 +12,6 @@ module Benchmarks.Builder
 import Test.Tasty.Bench (Benchmark, bgroup, bench, nf)
 import Data.Binary.Builder as B
 import Data.ByteString.Char8 ()
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid (mconcat, mempty)
-#endif
 import qualified Data.ByteString.Builder as Blaze
 import qualified Data.ByteString as SB
 import qualified Data.ByteString.Lazy as LB

benchmarks/haskell/Benchmarks/FileRead.hs

@@ -11,9 +11,6 @@ module Benchmarks.FileRead
     ( benchmark
     ) where
 
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative ((<$>))
-#endif
 import Test.Tasty.Bench (Benchmark, bgroup, bench, whnfIO)
 import qualified Data.ByteString as SB
 import qualified Data.ByteString.Lazy as LB

benchmarks/haskell/Benchmarks/Programs/BigTable.hs

@@ -12,9 +12,6 @@ module Benchmarks.Programs.BigTable
     ) where
 
 import Test.Tasty.Bench (Benchmark, bench, whnfIO)
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid (mconcat, mempty, mappend)
-#endif
 import Data.Text.Lazy.Builder (Builder, fromText, toLazyText)
 import Data.Text.Lazy.IO (hPutStr)
 import System.IO (Handle)

benchmarks/haskell/Benchmarks/Programs/Fold.hs

@@ -19,9 +19,6 @@ module Benchmarks.Programs.Fold
 
 import Data.List (foldl')
 import Data.List (intersperse)
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid (mempty, mappend, mconcat)
-#endif
 import System.IO (Handle)
 import Test.Tasty.Bench (Benchmark, bench, whnfIO)
 import qualified Data.Text as T

benchmarks/haskell/Benchmarks/Programs/Sort.hs

@@ -18,9 +18,6 @@ module Benchmarks.Programs.Sort
     ) where
 
 import Test.Tasty.Bench (Benchmark, bgroup, bench, whnfIO)
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid (mconcat)
-#endif
 import System.IO (Handle)
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as BL

benchmarks/haskell/Benchmarks/Pure.hs

@@ -15,9 +15,6 @@ module Benchmarks.Pure
 import Control.DeepSeq (NFData (..))
 import Control.Exception (evaluate)
 import Test.Tasty.Bench (Benchmark, bgroup, bench, nf)
-#if !MIN_VERSION_base(4,8,0)
-import Data.Monoid (mappend, mempty)
-#endif
 import GHC.Base (Char (..), Int (..), chr#, ord#, (+#))
 import GHC.Generics (Generic)
 import GHC.Int (Int64)
@@ -305,14 +302,6 @@ benchmark kind ~Env{..} =
     len l _ = l + (1::Int)
     short = T.pack "short"
 
-#if !MIN_VERSION_bytestring(0,10,0)
-instance NFData BS.ByteString
-
-instance NFData BL.ByteString where
-    rnf BL.Empty        = ()
-    rnf (BL.Chunk _ ts) = rnf ts
-#endif
-
 data B where
     B :: NFData a => a -> B
 

cabal.project

@@ -1,4 +1,3 @@
 packages: .
 tests: True
 benchmarks: True
-constraints: semigroups -text -hashable -unordered-containers

src/Data/Text.hs

@@ -1,19 +1,8 @@
 {-# LANGUAGE BangPatterns, CPP, MagicHash, Rank2Types, UnboxedTuples, TypeFamilies #-}
-{-# OPTIONS_GHC -fno-warn-orphans #-}
-#if __GLASGOW_HASKELL__ >= 702
-{-# LANGUAGE Trustworthy #-}
-#endif
--- Using TemplateHaskell in text unconditionally is unacceptable, as
--- it's a GHC boot library. TemplateHaskellQuotes was added in 8.0, so
--- this would seem to be a problem. However, GHC's policy of only
--- needing to be able to compile itself from the last few releases
--- allows us to use full-fat TH on older versions, while using THQ for
--- GHC versions that may be used for bootstrapping.
-#if __GLASGOW_HASKELL__ >= 800
 {-# LANGUAGE TemplateHaskellQuotes #-}
-#else
-{-# LANGUAGE TemplateHaskell #-}
-#endif
+{-# LANGUAGE Trustworthy #-}
+
+{-# OPTIONS_GHC -fno-warn-orphans #-}
 
 -- |
 -- Module      : Data.Text
@@ -226,9 +215,7 @@ import qualified Data.Text.Array as A
 import qualified Data.List as L
 import Data.Binary (Binary(get, put))
 import Data.Monoid (Monoid(..))
-#if MIN_VERSION_base(4,9,0)
 import Data.Semigroup (Semigroup(..))
-#endif
 import Data.String (IsString(..))
 import qualified Data.Text.Internal.Fusion as S
 import qualified Data.Text.Internal.Fusion.Common as S
@@ -251,14 +238,10 @@ import qualified Data.Text.Lazy as L
 import Data.Int (Int64)
 #endif
 import GHC.Base (eqInt, neInt, gtInt, geInt, ltInt, leInt)
-#if MIN_VERSION_base(4,7,0)
 import qualified GHC.Exts as Exts
-#endif
 import qualified Language.Haskell.TH.Lib as TH
 import qualified Language.Haskell.TH.Syntax as TH
-#if MIN_VERSION_base(4,7,0)
 import Text.Printf (PrintfArg, formatArg, formatString)
-#endif
 
 -- $setup
 -- >>> import Data.Text
@@ -364,37 +347,23 @@ instance Ord Text where
 instance Read Text where
     readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
 
-#if MIN_VERSION_base(4,9,0)
--- | Non-orphan 'Semigroup' instance only defined for
--- @base-4.9.0.0@ and later; orphan instances for older GHCs are
--- provided by
--- the [semigroups](http://hackage.haskell.org/package/semigroups)
--- package
---
--- @since 1.2.2.0
+-- | @since 1.2.2.0
 instance Semigroup Text where
     (<>) = append
-#endif
 
 instance Monoid Text where
     mempty  = empty
-#if MIN_VERSION_base(4,9,0)
-    mappend = (<>) -- future-proof definition
-#else
-    mappend = append
-#endif
+    mappend = (<>)
     mconcat = concat
 
 instance IsString Text where
     fromString = pack
 
-#if MIN_VERSION_base(4,7,0)
 -- | @since 1.2.0.0
 instance Exts.IsList Text where
     type Item Text = Char
     fromList       = pack
     toList         = unpack
-#endif
 
 instance NFData Text where rnf !_ = ()
 
@@ -442,13 +411,9 @@ instance TH.Lift Text where
   liftTyped = TH.unsafeTExpCoerce . TH.lift
 #endif
 
-#if MIN_VERSION_base(4,7,0)
--- | Only defined for @base-4.7.0.0@ and later
---
--- @since 1.2.2.0
+-- | @since 1.2.2.0
 instance PrintfArg Text where
   formatArg txt = formatString $ unpack txt
-#endif
 
 packConstr :: Constr
 packConstr = mkConstr textDataType "pack" [] Prefix

src/Data/Text/Array.hs

@@ -42,23 +42,16 @@ module Data.Text.Array
 
 #if defined(ASSERTS)
 import Control.Exception (assert)
+import GHC.Base (sizeofByteArray#, sizeofMutableByteArray#)
 #endif
-#if MIN_VERSION_base(4,4,0)
 import Control.Monad.ST.Unsafe (unsafeIOToST)
-#else
-import Control.Monad.ST (unsafeIOToST)
-#endif
 import Data.Bits ((.&.), xor)
 import Data.Text.Internal.Unsafe (inlinePerformIO)
 import Data.Text.Internal.Unsafe.Shift (shiftL, shiftR)
-#if MIN_VERSION_base(4,5,0)
 import Foreign.C.Types (CInt(CInt), CSize(CSize))
-#else
-import Foreign.C.Types (CInt, CSize)
-#endif
 import GHC.Base (ByteArray#, MutableByteArray#, Int(..),
                  indexWord16Array#, newByteArray#,
-                 unsafeFreezeByteArray#, writeWord16Array#, sizeofByteArray#, sizeofMutableByteArray#)
+                 unsafeFreezeByteArray#, writeWord16Array#)
 import GHC.ST (ST(..), runST)
 import GHC.Word (Word16(..))
 import Prelude hiding (length, read)