anchor.diff:        // We didn't split here, so add this chunk and its rule value to the
         // prefix and continue on to the next.
         var added = prefix.extend(_advancePrefix(prefix, value));
  -      _tryChunkRuleValues(solution, added, length);
  +      _tryChunkRuleValues(solution, added);
       }
     }
   
  
positive.code:     }
  
      var solution = new Solution(prefix);
      _tryChunkRuleValues(solution, prefix, prefix.column);
  
      if (debug.traceSplitter) {
        debug.unindent();
  
negative.code: 
    /// Updates [solution] with the best rule value selection for the chunk
    /// immediately following [prefix].
    void _tryChunkRuleValues(Solution solution, LinePrefix prefix) {
      // If we made it to the end, this prefix can be solved without splitting
      // any chunks.
      if (prefix.length == _chunks.length - 1) {
  