code: List<JCCase> switchBlockStatementGroups() {
          ListBuffer<JCCase> cases = new ListBuffer<JCCase>();
          while (true) {
              int pos = token.pos;
              switch (token.kind) {
              case CASE:
              case DEFAULT:
                  cases.append(switchBlockStatementGroup());
                  break;
              case RBRACE: case EOF:
                  return cases.toList();
              default:
                  nextToken(); // to ensure progress
                  syntaxError(pos, "expected3",
                      CASE, DEFAULT, RBRACE);
              }
          }
      }
docs: SwitchBlockStatementGroups = { SwitchBlockStatementGroup }
  SwitchBlockStatementGroup = SwitchLabel BlockStatements
  SwitchLabel = CASE ConstantExpression ":" | DEFAULT ":"