Same as https://github.com/facebook/react/issues/10103, but for the server renderer. You can look at implementation in https://github.com/facebook/react/pull/11168 and do something very similar in `ReactPartialRenderer.js`.
} else if (!React.isValidElement(nextChild)) {
        if (nextChild != null && nextChild.$$typeof != null) {
          // Catch unexpected special types early.
          const $$typeof = nextChild.$$typeof;
          invariant(
            $$typeof !== REACT_PORTAL_TYPE,
            'Portals are not currently supported by the server renderer. ' +
              'Render them conditionally so that they only appear on the client render.',
          );
          
          invariant(
            false,
            'Unknown element-like object type: %s. This is likely a bug in React. ' +
              'Please file an issue.',
            ($$typeof: any).toString(),
          );
        }
        const nextChildren = toArray(nextChild);
        const frame: Frame = {
          domNamespace: parentNamespace,
          children: nextChildren,
          childIndex: 0,
          context: context,
          footer: '',
        };
        if (__DEV__) {
          ((frame: any): FrameDev).debugElementStack = [];
        }
        this.stack.push(frame);
        return '';