@Override
  public boolean isSame(Object o) {
    if (o instanceof ExprNodeDynamicListDesc) {
      return source.equals(((ExprNodeDynamicListDesc)o).getSource());
    }
    return false;
  }
This expression represents a list that will be available at runtime.
ql/src/java/org/apache/hadoop/hive/ql/plan/ExprNodeDynamicListDesc.java