Use Prelude.fail to avoid ambiguity with fail from GHC.Base.

src/Text/Pandoc/Extensions.hs

@@ -397,7 +397,7 @@ parseFormatSpec = parse formatSpec ""
                        Just n  -> return n
                        Nothing
                          | name == "lhs" -> return Ext_literate_haskell
-                         | otherwise -> fail $ "Unknown extension: " ++ name
+                         | otherwise -> Prelude.fail $ "Unknown extension: " ++ name
           return $ case polarity of
                         '-' -> disableExtension ext
                         _   -> enableExtension ext

src/Text/Pandoc/Parsing.hs

@@ -343,16 +343,16 @@ notFollowedBy' p  = try $ join $  do  a <- try p
 -- (This version due to Andrew Pimlott on the Haskell mailing list.)
 
 oneOfStrings' :: Stream s m Char => (Char -> Char -> Bool) -> [String] -> ParserT s st m String
-oneOfStrings' _ []   = fail "no strings"
+oneOfStrings' _ []   = Prelude.fail "no strings"
 oneOfStrings' matches strs = try $ do
   c <- anyChar
   let strs' = [xs | (x:xs) <- strs, x `matches` c]
   case strs' of
-       []  -> fail "not found"
+       []  -> Prelude.fail "not found"
        _   -> (c:) <$> oneOfStrings' matches strs'
                <|> if "" `elem` strs'
                       then return [c]
-                      else fail "not found"
+                      else Prelude.fail "not found"
 
 -- | Parses one of a list of strings.  If the list contains
 -- two strings one of which is a prefix of the other, the longer
@@ -525,7 +525,7 @@ romanNumeral upperCase = do
                 hundreds + nineties + fifties + forties + tens + nines +
                 fives + fours + ones
     if total == 0
-       then fail "not a roman numeral"
+       then Prelude.fail "not a roman numeral"
        else return total
 
 -- Parsers for email addresses and URIs
@@ -698,7 +698,7 @@ characterReference = try $ do
                   _          -> ent ++ ";"
   case lookupEntity ent' of
        Just (c : _) -> return c
-       _            -> fail "entity not found"
+       _            -> Prelude.fail "entity not found"
 
 -- | Parses an uppercase roman numeral and returns (UpperRoman, number).
 upperRoman :: Stream s m Char => ParserT s st m (ListNumberStyle, Int)
@@ -1312,7 +1312,7 @@ failIfInQuoteContext :: (HasQuoteContext st m, Stream s m t)
                      -> ParserT s st m ()
 failIfInQuoteContext context = do
   context' <- getQuoteContext
-  when (context' == context) $ fail "already inside quotes"
+  when (context' == context) $ Prelude.fail "already inside quotes"
 
 charOrRef :: Stream s m Char => String -> ParserT s st m Char
 charOrRef cs =

src/Text/Pandoc/Readers/HTML.hs

@@ -445,7 +445,7 @@ headerLevel tagtype =
 --            return (level - 1))
 --            <|>
               return level
-        Nothing -> fail "Could not retrieve header level"
+        Nothing -> Prelude.fail "Could not retrieve header level"
 
 eTitlePage :: PandocMonad m => TagParser m ()
 eTitlePage = try $ do
@@ -1238,7 +1238,7 @@ htmlTag f = try $ do
           if stripComments
              then return (next, "")
              else return (next, "<!--" <> s <> "-->")
-         | otherwise -> fail "bogus comment mode, HTML5 parse error"
+         | otherwise -> Prelude.fail "bogus comment mode, HTML5 parse error"
        TagOpen tagname attr -> do
          guard $ isPI tagname || all (isName . fst) attr
          handleTag tagname

src/Text/Pandoc/Readers/LaTeX.hs

@@ -1239,7 +1239,7 @@ romanNumeralArg = spaces *> (parser <|> inBraces)
       Tok _ Word s <- satisfyTok isWordTok
       let (digits, rest) = T.span isDigit s
       unless (T.null rest) $
-        fail "Non-digits in argument to \\Rn or \\RN"
+        Prelude.fail "Non-digits in argument to \\Rn or \\RN"
       safeRead $ T.unpack digits
 
 newToggle :: (Monoid a, PandocMonad m) => [Tok] -> LP m a
@@ -2268,7 +2268,7 @@ parseAligns = try $ do
         case safeRead ds of
              Just n  ->
                getInput >>= setInput . (mconcat (replicate n spec) ++)
-             Nothing -> fail $ "Could not parse " ++ ds ++ " as number"
+             Nothing -> Prelude.fail $ "Could not parse " ++ ds ++ " as number"
   bgroup
   spaces
   maybeBar

src/Text/Pandoc/Readers/LaTeX/Parsing.hs

@@ -244,7 +244,7 @@ applyMacros s = (guardDisabled Ext_latex_macros >> return s) <|>
                       , sMacros  = extractMacros pstate }
       res <- runParserT retokenize lstate "math" (tokenize "math" (T.pack s))
       case res of
-           Left e   -> fail (show e)
+           Left e   -> Prelude.fail (show e)
            Right s' -> return s'
 
 tokenize :: SourceName -> Text -> [Tok]
@@ -452,7 +452,7 @@ doMacros' n inp = do
              lstate <- getState
              res <- lift $ runParserT getargs' lstate "args" ts
              case res of
-               Left _ -> fail $ "Could not parse arguments for " ++
+               Left _ -> Prelude.fail $ "Could not parse arguments for " ++
                                 T.unpack name
                Right (args, rest) -> do
                  -- first boolean param is true if we're tokenizing
@@ -576,11 +576,11 @@ primEscape = do
                     Just (c, _)
                       | c >= '\64' && c <= '\127' -> return (chr (ord c - 64))
                       | otherwise                 -> return (chr (ord c + 64))
-                    Nothing -> fail "Empty content of Esc1"
+                    Nothing -> Prelude.fail "Empty content of Esc1"
        Esc2 -> case safeRead ('0':'x':T.unpack (T.drop 2 t)) of
                     Just x  -> return (chr x)
-                    Nothing -> fail $ "Could not read: " ++ T.unpack t
-       _    -> fail "Expected an Esc1 or Esc2 token" -- should not happen
+                    Nothing -> Prelude.fail $ "Could not read: " ++ T.unpack t
+       _    -> Prelude.fail "Expected an Esc1 or Esc2 token" -- should not happen
 
 bgroup :: PandocMonad m => LP m Tok
 bgroup = try $ do

src/Text/Pandoc/Readers/Man.hs

@@ -131,7 +131,7 @@ parseTable = do
       Left _  -> do
         res' <- lift $ readWithMTokens blockstcell st ts'
         case res' of
-          Left _  -> fail "Could not parse table cell"
+          Left _  -> Prelude.fail "Could not parse table cell"
           Right x -> do
             modifyState $ \s -> s{ tableCellsPlain = False }
             return x
@@ -492,4 +492,4 @@ skipUnknownMacro = do
     ControlLine mkind _ pos -> do
       report $ SkippedContent ('.':mkind) pos
       return mempty
-    _                 -> fail "the impossible happened"
+    _                 -> Prelude.fail "the impossible happened"

src/Text/Pandoc/Readers/Markdown.hs

@@ -261,7 +261,7 @@ yamlBsToMeta bstr = do
 nodeToKey :: Monad m => YAML.Node YE.Pos -> m Text
 nodeToKey (YAML.Scalar _ (YAML.SStr t))       = return t
 nodeToKey (YAML.Scalar _ (YAML.SUnknown _ t)) = return t
-nodeToKey _                                 = fail "Non-string key in YAML mapping"
+nodeToKey _                                 = Prelude.fail "Non-string key in YAML mapping"
 
 toMetaValue :: PandocMonad m
             => Text -> MarkdownParser m (F MetaValue)
@@ -767,7 +767,7 @@ lhsCodeBlockInverseBird = lhsCodeBlockBirdWith '<'
 lhsCodeBlockBirdWith :: PandocMonad m => Char -> MarkdownParser m String
 lhsCodeBlockBirdWith c = try $ do
   pos <- getPosition
-  when (sourceColumn pos /= 1) $ fail "Not in first column"
+  when (sourceColumn pos /= 1) $ Prelude.fail "Not in first column"
   lns <- many1 $ birdTrackLine c
   -- if (as is normal) there is always a space after >, drop it
   let lns' = if all (\ln -> null ln || take 1 ln == " ") lns

src/Text/Pandoc/Readers/Muse.hs

@@ -496,7 +496,7 @@ amuseNoteBlockUntil end = try $ do
   ref <- noteMarker
   pos <- getPosition
   void spaceChar <|> lookAhead eol
-  (content, e) <- allowPara $ listItemContentsUntil (sourceColumn pos) (fail "x") end
+  (content, e) <- allowPara $ listItemContentsUntil (sourceColumn pos) (Prelude.fail "x") end
   addNote ref pos content
   return (mempty, e)
 
@@ -558,7 +558,7 @@ museOrderedListMarker style =
               LowerRoman -> lowerRoman
               UpperAlpha -> upperAlpha
               LowerAlpha -> lowerAlpha
-              _          -> fail "Unhandled case"
+              _          -> Prelude.fail "Unhandled case"
 
 orderedListItemsUntil :: PandocMonad m
                       => Int

src/Text/Pandoc/Readers/RST.hs

@@ -312,7 +312,7 @@ doubleHeader' = try $ do
   txt <- trimInlines . mconcat <$> many1 (notFollowedBy blankline >> inline)
   pos <- getPosition
   let len = sourceColumn pos - 1
-  when (len > lenTop) $ fail "title longer than border"
+  when (len > lenTop) $ Prelude.fail "title longer than border"
   blankline              -- spaces and newline
   count lenTop (char c)  -- the bottom line
   blanklines

src/Text/Pandoc/Readers/Roff.hs

@@ -180,7 +180,7 @@ resolveGlyph delimChar glyph = do
             '['  -> escUnknown ("\\[" ++ glyph ++ "]")
             '('  -> escUnknown ("\\(" ++ glyph)
             '\'' -> escUnknown ("\\C'" ++ glyph ++ "'")
-            _    -> fail "resolveGlyph: unknown glyph delimiter"
+            _    -> Prelude.fail "resolveGlyph: unknown glyph delimiter"
 
 readUnicodeChar :: String -> Maybe Char
 readUnicodeChar ('u':cs@(_:_:_:_:_)) =
@@ -562,7 +562,7 @@ resolveMacro macroName args pos = do
 lexStringDef :: PandocMonad m => [Arg] -> RoffLexer m RoffTokens
 lexStringDef args = do -- string definition
    case args of
-     []     -> fail "No argument to .ds"
+     []     -> Prelude.fail "No argument to .ds"
      (x:ys) -> do
        let ts = singleTok $ TextLine (intercalate [RoffStr " " ] ys)
        let stringName = linePartsToString x
@@ -578,7 +578,7 @@ lexMacroDef args = do -- macro definition
        (x : y : _) -> return (linePartsToString x, linePartsToString y)
                       -- optional second arg
        (x:_)       -> return (linePartsToString x, ".")
-       []          -> fail "No argument to .de"
+       []          -> Prelude.fail "No argument to .de"
    let stop = try $ do
          char '.' <|> char '\''
          skipMany spacetab

src/Text/Pandoc/Readers/Textile.hs

@@ -484,7 +484,7 @@ note = try $ do
   ref <- char '[' *> many1 digit <* char ']'
   notes <- stateNotes <$> getState
   case lookup ref notes of
-    Nothing  -> fail "note not found"
+    Nothing  -> Prelude.fail "note not found"
     Just raw -> B.note <$> parseFromString' parseBlocks raw
 
 -- | Special chars

src/Text/Pandoc/Translations.hs

@@ -71,7 +71,7 @@ newtype Translations = Translations (M.Map Term String)
 instance FromJSON Term where
   parseJSON (String t) = case safeRead (T.unpack t) of
                                Just t' -> pure t'
-                               Nothing -> fail $ "Invalid Term name " ++
+                               Nothing -> Prelude.fail $ "Invalid Term name " ++
                                                  show t
   parseJSON invalid = Aeson.typeMismatch "Term" invalid
 
@@ -79,7 +79,7 @@ instance YAML.FromYAML Term where
   parseYAML (YAML.Scalar _ (YAML.SStr t)) =
                          case safeRead (T.unpack t) of
                                Just t' -> pure t'
-                               Nothing -> fail $ "Invalid Term name " ++
+                               Nothing -> Prelude.fail $ "Invalid Term name " ++
                                                  show t
   parseYAML invalid = YAML.typeMismatch "Term" invalid
 
@@ -89,7 +89,7 @@ instance FromJSON Translations where
     return $ Translations (M.fromList xs)
     where addItem (k,v) =
             case safeRead (T.unpack k) of
-                 Nothing -> fail $ "Invalid Term name " ++ show k
+                 Nothing -> Prelude.fail $ "Invalid Term name " ++ show k
                  Just t  ->
                    case v of
                         (String s) -> return (t, T.unpack $ T.strip s)

src/Text/Pandoc/Writers/Docx.hs

@@ -580,7 +580,7 @@ writeDocx opts doc@(Pandoc meta _) = do
   settingsEntry <- copyChildren refArchive distArchive settingsPath epochtime settingsList
 
   let entryFromArchive arch path =
-         maybe (fail $ path ++ " missing in reference docx")
+         maybe (Prelude.fail $ path ++ " missing in reference docx")
                return
                (findEntryByPath path arch `mplus` findEntryByPath path distArchive)
   docPropsAppEntry <- entryFromArchive refArchive "docProps/app.xml"

src/Text/Pandoc/Writers/HTML.hs

@@ -429,7 +429,7 @@ parseMailto s =
          let (name', rest) = span (/='@') addr
          let domain = drop 1 rest
          return (name', domain)
-       _ -> fail "not a mailto: URL"
+       _ -> Prelude.fail "not a mailto: URL"
 
 -- | Obfuscate a "mailto:" link.
 obfuscateLink :: PandocMonad m

src/Text/Pandoc/Writers/Muse.hs

@@ -607,7 +607,7 @@ inlineToMuse (Subscript lst) = do
   modify $ \st -> st { stUseTags = False }
   return $ "<sub>" <> contents <> "</sub>"
 inlineToMuse SmallCaps {} =
-  fail "SmallCaps should be expanded before normalization"
+  Prelude.fail "SmallCaps should be expanded before normalization"
 inlineToMuse (Quoted SingleQuote lst) = do
   contents <- inlineListToMuse lst
   modify $ \st -> st { stUseTags = False }
@@ -617,7 +617,7 @@ inlineToMuse (Quoted DoubleQuote lst) = do
   modify $ \st -> st { stUseTags = False }
   return $ "“" <> contents <> "”"
 inlineToMuse Cite {} =
-  fail "Citations should be expanded before normalization"
+  Prelude.fail "Citations should be expanded before normalization"
 inlineToMuse (Code _ str) = do
   useTags <- gets stUseTags
   modify $ \st -> st { stUseTags = False }
@@ -625,7 +625,7 @@ inlineToMuse (Code _ str) = do
              then "<code>" <> text (substitute "</code>" "<</code><code>/code>" str) <> "</code>"
              else "=" <> text str <> "="
 inlineToMuse Math{} =
-  fail "Math should be expanded before normalization"
+  Prelude.fail "Math should be expanded before normalization"
 inlineToMuse (RawInline (Format f) str) = do
   modify $ \st -> st { stUseTags = False }
   return $ "<literal style=\"" <> text f <> "\">" <> text str <> "</literal>"

src/Text/Pandoc/Writers/OOXML.hs

@@ -54,9 +54,9 @@ parseXml :: (PandocMonad m) => Archive -> Archive -> String -> m Element
 parseXml refArchive distArchive relpath =
   case findEntryByPath relpath refArchive `mplus`
          findEntryByPath relpath distArchive of
-            Nothing -> fail $ relpath ++ " missing in reference file"
+            Nothing -> Prelude.fail $ relpath ++ " missing in reference file"
             Just e  -> case parseXMLDoc . UTF8.toStringLazy . fromEntry $ e of
-                       Nothing -> fail $ relpath ++ " corrupt in reference file"
+                       Nothing -> Prelude.fail $ relpath ++ " corrupt in reference file"
                        Just d  -> return d
 
 -- Copied from Util

src/Text/Pandoc/Writers/Powerpoint/Output.hs

@@ -173,7 +173,7 @@ copyFileToArchive arch fp = do
   refArchive <- asks envRefArchive
   distArchive <- asks envDistArchive
   case findEntryByPath fp refArchive `mplus` findEntryByPath fp distArchive of
-    Nothing -> fail $ fp ++ " missing in reference file"
+    Nothing -> Prelude.fail $ fp ++ " missing in reference file"
     Just e -> return $ addEntryToArchive e arch
 
 alwaysInheritedPatterns :: [Pattern]