anchor.diff:                          if curSymbol derivedKernels.[j] = i && not newDerivedLookaheads.[j].IsEmpty then hasNewLookahead <- true
                       let destStates = new Dictionary<int, Set<int>>()
                       if hasNewLookahead then
  -                        let mutable stackSet = Set.empty
  -                        let mutable dontStackSet = Set.empty
  +//                        let mutable stackSet = Set.empty
  +//                        let mutable dontStackSet = Set.empty
                           for j = 0 to mainKernels.Length-1 do
                               if curSymbol mainKernels.[j] = i then
                                   let nextKernels = KernelInterpreter.nextPos grammar mainKernels.[j]
  -                                dontStackSet <- Set.add (KernelInterpreter.getProd mainKernels.[j]) dontStackSet 
  +//                                dontStackSet <- Set.add (KernelInterpreter.getProd mainKernels.[j]) dontStackSet 
                                   for nextKernel in nextKernels do
                                       if not <| destStates.ContainsKey nextKernel then
                                           destStates.[nextKernel] <- newMainLookaheads.[j]
  
positive.code:                     diffDerived.[i] <- diffSet
                  vertex, diffMain, diffDerived, needDfs
              else
                  let vertex = new Vertex<int,int * (Set<int> * Set<int>)>(nextIndex())
                  wasEdge.Add Set.empty
                  vertices.Add vertex
                  kernelsToVertex.[key] <- vertex
  
negative.code:                     for j = 0 to derivedKernels.Length-1 do
                              if curSymbol derivedKernels.[j] = i && not derivedLookaheads.[j].IsEmpty then
                                  let nextKernels = KernelInterpreter.nextPos grammar derivedKernels.[j]
  //                                stackSet <- Set.add (KernelInterpreter.getProd derivedKernels.[j]) stackSet
                                  for nextKernel in nextKernels do
                                      if not <| destStates.ContainsKey nextKernel then
                                          destStates.[nextKernel] <- derivedLookaheads.[j]
  