QML Cannot assign to non-existent default property

pragma Singleton
import QtQuick 2.15
import Qt.labs.settings 1.1

QtObject {

    property string name: "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
    // 配置存储
    Settings {
        id: settings
        category: "Theme"

qrc:/QPlayer/layout/Theme.qml:9:5: Cannot assign to non-existent default property

property必须赋给可视对象，或者说是QtQuick对象，QtObject是最基础的基类，无法添加子对象，或者

// 声明一个默认属性，这样任何子对象都能被自动加进来
    default property list<QtObject> children