diff --git a/Language/Haskell/GhcMod/Rewrite.hs b/Language/Haskell/GhcMod/Rewrite.hs
index f1d5346..3b62783 100644
--- a/Language/Haskell/GhcMod/Rewrite.hs
+++ b/Language/Haskell/GhcMod/Rewrite.hs
@@ -257,7 +257,7 @@ sig opt file lineNo colNo = ghandle handler body
         modSum <- Gap.fileModSummary file
         sigTy <- getSignature modSum lineNo colNo
         case sigTy of
-          Nothing -> return ""
+          Nothing -> return $ convert opt ([] :: [String])
           Just (Signature loc names ty) -> do
             return $ convert opt $ ( "function"
                                    , fourInts loc
diff --git a/elisp/ghc-rewrite.el b/elisp/ghc-rewrite.el
index 05384d6..90f5138 100644
--- a/elisp/ghc-rewrite.el
+++ b/elisp/ghc-rewrite.el
@@ -23,14 +23,17 @@
   (let ((info (ghc-obtain-case-split)))
     (if (null info)
 	(message "Cannot split in cases")
-	(let ((varinfo (car info))
-	      (declinfo (cadr info))
-	      (cases (caddr info)))
-	  (message cases)
-	  )
-      )
-    )
-  )
+	(let* ((current-line    (line-number-at-pos))
+	       (begin-line      (ghc-sinfo-get-beg-line info))
+	       (begin-line-diff (+ 1 (- begin-line current-line)))
+	       (begin-line-pos  (line-beginning-position begin-line-diff))
+	       (begin-pos       (- (+ begin-line-pos (ghc-sinfo-get-beg-column info)) 1))
+	       (end-line        (ghc-sinfo-get-end-line info))
+	       (end-line-diff   (+ 1 (- end-line current-line)))
+	       (end-line-pos    (line-beginning-position end-line-diff))
+	       (end-pos         (- (+ end-line-pos (ghc-sinfo-get-end-column info)) 1)) )
+	    (delete-region begin-pos end-pos)
+	    (insert (ghc-sinfo-get-info info)) ) )))
 
 (defun ghc-obtain-case-split ()
   (let* ((ln (int-to-string (line-number-at-pos)))