class IncrementStackDepth {
   public:
    explicit IncrementStackDepth(PredicateFactory* parent) : parent_(parent) {
      parent_->stack_depth_++;
    }

    bool HasOverflowed() const {
      const int kMaxStackDepth = 8;
      return parent_->stack_depth_ >= kMaxStackDepth;
    }

    ~IncrementStackDepth() { parent_->stack_depth_--; }

   private: