anchor.diff:                      // Add this new DFA state to the set of unvisited states
                       // targeted by transitions from the current DFA state.
                       let unvisitedTransitionTargets =
  -                        Set.add newDfaState unvisitedTransitionTargets
  +                        TagSet.add newDfaState unvisitedTransitionTargets
   
                       newDfaState,
                       unvisitedTransitionTargets,
  
positive.code: 
      // Compile the DFA.
      let compilationState =
          let initialPending = Set.singleton initialDfaStateId
          createDfa initialPending compilationState
  
      //
  
negative.code:             // add the DFA state to the compilation state (if necessary), then add an edge
              // to the transition graph from this DFA state to the target DFA state.
              let transitionsFromCurrentDfaState, unvisitedTransitionTargets, compilationState =
                  ((Map.empty, TagSet.empty, compilationState), derivativeClasses.Elements)
                  ||> CharSet.fold (fun state element ->
                      // TEMP : The Elements field of DerivativeClasses needs to be redefined
                      // because it is possible for a class to contain multiple values.
                      let derivClass = CharSet.singleton element
                      transitions regularVector derivClass state)
  
              // Add any newly-created, unvisited states to the
              // set of states which still need to be visited.
              let pending = TagSet.union pending unvisitedTransitionTargets
  
              let compilationState =
                  { compilationState with
  