UnhelpfulSpan fixes

haddock-api/src/Haddock/Backends/Hyperlinker/Parser.hs

@@ -31,12 +31,20 @@ chunk str@(c:_)
 chunk str
     | "--" `isPrefixOf` str = chunk' $ spanToNewline str
     | "{-" `isPrefixOf` str = chunk' $ chunkComment 0 str
-    | otherwise = case lex str of
+    | otherwise = case lex' str of
         (tok:_) -> chunk' tok
         [] -> [str]
   where
     chunk' (c, rest) = c:(chunk rest)
 
+-- | A bit better lexer then the default, i.e. handles DataKinds quotes
+lex' :: ReadS String
+lex' ('\'' : '\'' : rest)              = [("''", rest)]
+lex' str@('\'' : '\\' : _ : '\'' : _)  = lex str
+lex' str@('\'' : _ : '\'' : _)         = lex str
+lex' ('\'' : rest)                     = [("'", rest)]
+lex' str                               = lex str
+
 -- | Split input to "first line" string and the rest of it.
 --
 -- Ideally, this should be done simply with @'break' (== '\n')@. However,
@@ -124,6 +132,8 @@ classify str
     | "--" `isPrefixOf` str = TkComment
     | "{-#" `isPrefixOf` str = TkPragma
     | "{-" `isPrefixOf` str = TkComment
+classify "''" = TkSpecial
+classify "'"  = TkSpecial
 classify str@(c:_)
     | isSpace c = TkSpace
     | isDigit c = TkNumber

haddock-api/src/Haddock/Backends/Hyperlinker/Types.hs

@@ -12,16 +12,19 @@ data Token = Token
     , tkValue :: String
     , tkSpan :: Span
     }
+    deriving (Show)
 
 data Position = Position
     { posRow :: !Int
     , posCol :: !Int
     }
+    deriving (Show)
 
 data Span = Span
     { spStart :: Position
     , spEnd :: Position
     }
+    deriving (Show)
 
 data TokenType
     = TkIdentifier

haddock-api/src/Haddock/Backends/Xhtml/Utils.hs

@@ -75,8 +75,7 @@ spliceURL' maybe_file maybe_mod maybe_name maybe_loc = run
       case span_ of
       RealSrcSpan span__ ->
         show $ srcSpanStartLine span__
-      UnhelpfulSpan _ ->
-        error "spliceURL UnhelpfulSpan"
+      UnhelpfulSpan _ -> ""
 
   run "" = ""
   run ('%':'M':rest) = mdl  ++ run rest