fix MultilineStrings with let

compiler/GHC/Driver/MultilineStrings.hs

@@ -3,30 +3,32 @@ module GHC.Driver.MultilineStrings where
 import GHC.Prelude
 
 convertMultilineStrings :: String -> String
-convertMultilineStrings s = go s WaitingForString
+convertMultilineStrings s = go s WaitingForString 0
  where
- go s state = case state of
+ go s state charCnt = case state of
   WaitingForString -> case s of
    "" -> ""
    '-':'-':s -> '-':'-': skipOneLineComment s
    '{':'-':s -> '{':'-': skipComment s
-   '"':'"':'"':'\n':'"':'"':'"':s -> '"':'"': go s state
-   '"':'"':'"':'\n':s -> '\n':' ':'"' : go s InString
-   c:s -> c : go s state
+   '"':'"':'"':'\n':'"':'"':'"':s -> '"':'"': go s state 3
+   '"':'"':'"':'\n':s -> '\n':' ':'"' : go s InString charCnt
+   '\n':s -> '\n' : go s state 0
+   c:s -> c : go s state (charCnt + 1)
   InString -> case s of
    "" -> error "we are in a mutline string, but text ended unexpectedly"
-   '\n':'"':'"':'"':s -> '"':'\n' : go s WaitingForString
-   '"':s -> '\\':'"' : go s state
-   '\\':s -> '\\':'\\' : go s state
-   '\n':s -> '\\':'n':'"':'\n':' ':'+':'+':' ':'"' : go s state
-   c:s -> c : go s state
+   '\n':'"':'"':'"':s -> '"':'\n' : go s WaitingForString 0
+   '"':s -> '\\':'"' : go s state charCnt
+   '\\':s -> '\\':'\\' : go s state charCnt
+   -- '\n':s -> '\\':'n':'"':'\n':' ':'+':'+':' ':'"' : go s state charCnt
+   '\n':s -> "\\n\"\n" ++ replicate charCnt ' ' ++ " ++ \"" ++ go s state charCnt
+   c:s -> c : go s state charCnt
   where
-  skipOneLineComment "" = go "" state
-  skipOneLineComment s@('\n':_) = go s state
+  skipOneLineComment "" = go "" state charCnt
+  skipOneLineComment s@('\n':_) = go s state charCnt
   skipOneLineComment (c:s) = c : skipOneLineComment s
 
-  skipComment "" = go "" state
-  skipComment ('-':'}':s) = '-':'}': go s state
+  skipComment "" = go "" state charCnt
+  skipComment ('-':'}':s) = '-':'}': go s state charCnt
   skipComment (c:s) = c : skipComment s
 
 data State