- Spanner *sp = dynamic_cast<Spanner*> (me);
- int left = sp->get_bound (LEFT)->get_column ()->get_rank ();
- int right = sp->get_bound (RIGHT)->get_column ()->get_rank ();
+ Spanner *sp = dynamic_cast<Spanner *> (me);
+ int left = 0;
+ int right = INT_MAX;
+ if (Item *l = sp->get_bound (LEFT))
+ left = l->get_column ()->get_rank ();
+ if (Item *r = sp->get_bound (RIGHT))
+ right = r->get_column ()->get_rank ();