src/Pure/General/scan.ML

 
 (* finite scans *)
 
 fun finite' (stopper, is_stopper) scan (state, input) =
   let
-    fun lost () = raise ABORT "Scanner bug: lost stopper of finite scan!";
+    fun lost () = raise ABORT "Bad scanner: lost stopper of finite scan!";
 
     fun stop [] = lost ()
       | stop lst =
           let val (xs, x) = split_last lst
           in if is_stopper x then ((), xs) else lost () end;