Remove `Documentation.Haddock.Utf8`

The circumstances under which this module appeared are completely gone.
The Hyperlinker backend no longer needs this module (it uses the more
efficient `Encoding` module from `ghc`).

Why no deprecation? Because this module really shouldn't exist!

  - It isn't used in `haddock-library`/`haddock-api` anymore
  - It was copy pasted directly from `utf8-string`
  - Folks seeking a boot-lib only solution can use `ghc`'s `Encoding`

6 files changed, 7 insertions, 96 deletions

diff --git a/haddock-api/haddock-api.cabal b/haddock-api/haddock-api.cabal
index a4dea01f..af5fd683 100644
--- a/haddock-api/haddock-api.cabal
+++ b/haddock-api/haddock-api.cabal
@@ -46,7 +46,7 @@ library
                , Cabal           ^>= 2.4.0
                , ghc             ^>= 8.7
                , ghc-paths       ^>= 0.1.0.9
-               , haddock-library ^>= 1.7.0
+               , haddock-library ^>= 1.8.0
                , xhtml           ^>= 3000.2.2
 
   -- Versions for the dependencies below are transitively pinned by
@@ -170,7 +170,7 @@ test-suite spec
   build-depends: Cabal           ^>= 2.4
                , ghc             ^>= 8.7
                , ghc-paths       ^>= 0.1.0.9
-               , haddock-library ^>= 1.7.0
+               , haddock-library ^>= 1.8.0
                , xhtml           ^>= 3000.2.2
                , hspec           >= 2.4.4 && < 2.6
                , QuickCheck      ^>= 2.11
diff --git a/haddock-library/CHANGES.md b/haddock-library/CHANGES.md
index 971d8dc7..265579ca 100644
--- a/haddock-library/CHANGES.md
+++ b/haddock-library/CHANGES.md
@@ -1,7 +1,10 @@
-## TBA
+## Changes in version 1.8.0
 
  * Support inline markup in markdown-style links (#875)
 
+ * Remove now unused `Documentation.Haddock.Utf8` module.
+   This module was anyways copied from the `utf8-string` package.
+
 ## Changes in version 1.7.0
 
  * Make `Documentation.Haddock.Parser.Monad` an internal module
diff --git a/haddock-library/haddock-library.cabal b/haddock-library/haddock-library.cabal
index b19642ab..b24db5d4 100644
--- a/haddock-library/haddock-library.cabal
+++ b/haddock-library/haddock-library.cabal
@@ -1,6 +1,6 @@
 cabal-version:        2.2
 name:                 haddock-library
-version:              1.7.0
+version:              1.8.0
 synopsis:             Library exposing some functionality of Haddock.
 
 description:          Haddock is a documentation-generation tool for Haskell
@@ -45,7 +45,6 @@ library
     Documentation.Haddock.Markup
     Documentation.Haddock.Parser
     Documentation.Haddock.Types
-    Documentation.Haddock.Utf8
 
   other-modules:
     Documentation.Haddock.Parser.Util
@@ -71,8 +70,6 @@ test-suite spec
       Documentation.Haddock.Parser.UtilSpec
       Documentation.Haddock.ParserSpec
       Documentation.Haddock.Types
-      Documentation.Haddock.Utf8
-      Documentation.Haddock.Utf8Spec
 
   build-depends:
     , base-compat  ^>= 0.9.3 || ^>= 0.10.0
diff --git a/haddock-library/src/Documentation/Haddock/Utf8.hs b/haddock-library/src/Documentation/Haddock/Utf8.hs
deleted file mode 100644
index 3f75e53b..00000000
--- a/haddock-library/src/Documentation/Haddock/Utf8.hs
+++ /dev/null
@@ -1,74 +0,0 @@
-module Documentation.Haddock.Utf8 (encodeUtf8, decodeUtf8) where
-import           Data.Bits ((.|.), (.&.), shiftL, shiftR)
-import qualified Data.ByteString as BS
-import           Data.Char (chr, ord)
-import           Data.Word (Word8)
-
--- | Helper that encodes and packs a 'String' into a 'BS.ByteString'
-encodeUtf8 :: String -> BS.ByteString
-encodeUtf8 = BS.pack . encode
-
--- | Helper that unpacks and decodes a 'BS.ByteString' into a 'String'
-decodeUtf8 :: BS.ByteString -> String
-decodeUtf8 = decode . BS.unpack
-
--- Copy/pasted functions from Codec.Binary.UTF8.String for encoding/decoding
--- | Character to use when 'encode' or 'decode' fail for a byte.
-replacementCharacter :: Char
-replacementCharacter = '\xfffd'
-
--- | Encode a Haskell String to a list of Word8 values, in UTF8 format.
-encode :: String -> [Word8]
-encode = concatMap (map fromIntegral . go . ord)
- where
-  go oc
-   | oc <= 0x7f       = [oc]
-
-   | oc <= 0x7ff      = [ 0xc0 + (oc `shiftR` 6)
-                        , 0x80 + oc .&. 0x3f
-                        ]
-
-   | oc <= 0xffff     = [ 0xe0 + (oc `shiftR` 12)
-                        , 0x80 + ((oc `shiftR` 6) .&. 0x3f)
-                        , 0x80 + oc .&. 0x3f
-                        ]
-   | otherwise        = [ 0xf0 + (oc `shiftR` 18)
-                        , 0x80 + ((oc `shiftR` 12) .&. 0x3f)
-                        , 0x80 + ((oc `shiftR` 6) .&. 0x3f)
-                        , 0x80 + oc .&. 0x3f
-                        ]
-
--- | Decode a UTF8 string packed into a list of Word8 values, directly to String
-decode :: [Word8] -> String
-decode [    ] = ""
-decode (c:cs)
-  | c < 0x80  = chr (fromEnum c) : decode cs
-  | c < 0xc0  = replacementCharacter : decode cs
-  | c < 0xe0  = multi1
-  | c < 0xf0  = multi_byte 2 0xf  0x800
-  | c < 0xf8  = multi_byte 3 0x7  0x10000
-  | c < 0xfc  = multi_byte 4 0x3  0x200000
-  | c < 0xfe  = multi_byte 5 0x1  0x4000000
-  | otherwise = replacementCharacter : decode cs
-  where
-    multi1 = case cs of
-      c1 : ds | c1 .&. 0xc0 == 0x80 ->
-        let d = ((fromEnum c .&. 0x1f) `shiftL` 6) .|.  fromEnum (c1 .&. 0x3f)
-        in if d >= 0x000080 then toEnum d : decode ds
-                            else replacementCharacter : decode ds
-      _ -> replacementCharacter : decode cs
-
-    multi_byte :: Int -> Word8 -> Int -> String
-    multi_byte i mask overlong = aux i cs (fromEnum (c .&. mask))
-      where
-        aux 0 rs acc
-          | overlong <= acc && acc <= 0x10ffff &&
-            (acc < 0xd800 || 0xdfff < acc)     &&
-            (acc < 0xfffe || 0xffff < acc)      = chr acc : decode rs
-          | otherwise = replacementCharacter : decode rs
-
-        aux n (r:rs) acc
-          | r .&. 0xc0 == 0x80 = aux (n-1) rs
-                               $ shiftL acc 6 .|. fromEnum (r .&. 0x3f)
-
-        aux _ rs     _ = replacementCharacter : decode rs
diff --git a/haddock-library/test/Documentation/Haddock/Utf8Spec.hs b/haddock-library/test/Documentation/Haddock/Utf8Spec.hs
deleted file mode 100644
index 47e12704..00000000
--- a/haddock-library/test/Documentation/Haddock/Utf8Spec.hs
+++ /dev/null
@@ -1,14 +0,0 @@
-module Documentation.Haddock.Utf8Spec (main, spec) where
-
-import Test.Hspec
-import Test.QuickCheck
-import Documentation.Haddock.Utf8
-
-main :: IO ()
-main = hspec spec
-
-spec :: Spec
-spec = do
-  describe "decodeUtf8" $ do
-    it "is inverse to encodeUtf8" $ do
-      property $ \xs -> (decodeUtf8 . encodeUtf8) xs `shouldBe` xs
diff --git a/haddock.cabal b/haddock.cabal
index c0fc3a4f..2b8ee6ff 100644
--- a/haddock.cabal
+++ b/haddock.cabal
@@ -91,7 +91,6 @@ executable haddock
       Documentation.Haddock.Parser.Monad
       Documentation.Haddock.Types
       Documentation.Haddock.Doc
-      Documentation.Haddock.Utf8
       Documentation.Haddock.Parser.Util
       Documentation.Haddock.Markup