docs: protected Set<AbstractExpression> findAllSubexpressionsOfClass(Class< ? extends AbstractExpression> aeClass) {
          HashSet<AbstractExpression> exprs = new HashSet<>();
          if (m_joinTree != null) {
              AbstractExpression treeExpr = m_joinTree.getAllFilters();
              if (treeExpr != null) {
                  exprs.addAll(treeExpr.findAllSubexpressionsOfClass(aeClass));
              }
          }
          return exprs;
      }