docs: private void checkViewSources(ArrayList<Table> tableList) throws VoltCompilerException {
          HashSet<String> tableSet = new HashSet<>();
          for (Table tbl : tableList) {
              if (! tableSet.add(tbl.getTypeName())) {
                  String errMsg = "Table " + tbl.getTypeName() + " appeared in the table list more than once: " +
                                  "materialized view does not support self-join.";
                  throw m_compiler.new VoltCompilerException(errMsg);
              }
          }
      }