code: List<JCExpression> arguments() {
          ListBuffer<JCExpression> args = new ListBuffer<>();
          if (token.kind == LPAREN) {
              nextToken();
              if (token.kind != RPAREN) {
                  args.append(parseExpression());
                  while (token.kind == COMMA) {
                      nextToken();
                      args.append(parseExpression());
                  }
              }
              accept(RPAREN);
          } else {
              syntaxError(token.pos, "expected", LPAREN);
          }
          return args.toList();
      }
docs: Arguments = "(" [Expression { COMMA Expression }] ")"