Can't use the properties and signals when definitions such as them are enabled by `__has_include`

When enabling definitions of properties, signals, etc. using `TEST_EXIST_FOR_TEST_NG` defined by `__has_include` as follows, the following issues.

1. Properties or signals cannot be used from QML.
2. When using `SIGNAL` or `SLOT` in QObject::connect, the target function cannot use.

• testNG.h

  #ifndef TESTNG_H
  #define TESTNG_H
  
  #include <QDebug>
  
  #if __has_include("test.h")
  #include "test.h"
  #define TEST_EXIST_FOR_TEST_NG
  #endif
  
  class TestNG : public QObject
  {
      Q_OBJECT
  #ifdef TEST_EXIST_FOR_TEST_NG
      Q_PROPERTY(int num READ num WRITE setNum NOTIFY numChanged)
  #endif // TEST_EXIST_FOR_TEST_NG
  
  public:
      TestNG() : QObject(nullptr) {}
  #ifdef TEST_EXIST_FOR_TEST_NG
      TestNG(Test *test)
          : QObject(nullptr)
          , mTest(test)
      {
          qDebug()
              << static_cast<bool>(
                  QObject::connect(
                      mTest,
                      SIGNAL(numChanged()),
                      this,
                      SLOT(slotTest())));
      }
      int num() const
      {
          return mNum;
      }
  
  signals:
      void numChanged();
      void calledSlotTest();
  
  public slots:
      void setNum(const int &nNum)
      {
          if (nNum != mNum) {
              mNum = nNum;
              emit numChanged();
          }
      }
      void slotTest()
      {
          qDebug() << __FUNCTION__;
          emit calledSlotTest();
      }
  
  private:
      Test *mTest;
  
  protected:
      int mNum = 0;
  #endif // TEST_EXIST_FOR_TEST_NG
  };
  
  #endif // TESTNG_H
  

• test.h

  #ifndef TEST_H
  #define TEST_H
  
  #include <QObject>
  #include <QDebug>
  
  class Test : public QObject
  {
      Q_OBJECT
      Q_PROPERTY(int num READ num WRITE setNum NOTIFY numChanged)
  
  public:
      Test() : QObject(nullptr) {}
      int num() const
      {
          return mNum;
      }
  
  signals:
      void numChanged();
      void calledSlotTest();
  
  public slots:
      void setNum(const int &nNum)
      {
          if (nNum != mNum) {
              mNum = nNum;
              emit numChanged();
          }
      }
      void slotTest()
      {
          qDebug() << __FUNCTION__;
          emit calledSlotTest();
      }
  
  protected:
      int mNum = 0;
  };
  
  #endif // TEST_H
  

• main.cpp

  #include <QGuiApplication>
  #include <QQmlApplicationEngine>
  #include <QQmlContext>
  
  #include "test.h"
  #include "testNG.h"
  
  int main(int argc, char *argv[])
  {
      QGuiApplication app(argc, argv);
  
      QQmlApplicationEngine engine;
  
      Test testObj;
      engine.rootContext()->setContextProperty("Test", &testObj);
  #ifdef TEST_EXIST_FOR_TEST_NG
      TestNG testNGObj(&testObj);
  #else
      TestNG testNGObj();
  #endif // TEST_EXIST_FOR_TEST_NG
      engine.rootContext()->setContextProperty("TestNG", &testNGObj);
  
      QObject::connect(
          &engine,
          &QQmlApplicationEngine::objectCreationFailed,
          &app,
          []() { QCoreApplication::exit(-1); },
          Qt::QueuedConnection);
      engine.loadFromModule("Main", "Main");
  
      return app.exec();
  }
  

• Main.qml

  import QtQuick
  import QtQuick.Controls
  import QtQuick.Layouts
  import QtQml.Models
  import Main
  
  Window {
      id: root
      objectName: "Main.qml"
      width: 640
      height: 480
      visible: true
      title: qsTr("Main")
  
      property ObjectModel testModel: ObjectModel {
          Component.onCompleted: {
              root.testModel.append(Test)
              root.testModel.append(TestNG)
          }
      }
  
      ScrollView {
          anchors.fill: parent
          ColumnLayout {
              Repeater {
                  id: contentsRepeater
                  model: root.testModel.count
                  delegate: RowLayout {
                      id: contentsRepeaterDelegate
                      required property int index
                      readonly property var target: root.testModel.get(index)
                      Text {
                          text: "" + contentsRepeaterDelegate.target
                      }
                      GridLayout {
                          columns: 2
                          Text {
                              text: "num"
                          }
                          Text {
                              text: contentsRepeaterDelegate.target.num
                          }
                          Button {
                              Layout.columnSpan: 2
                              text: "num count up"
                              onReleased: {
                                  contentsRepeaterDelegate.target.num = contentsRepeaterDelegate.target.num + 1;
                              }
                          }
                          Text {
                              text: "onNumChangedTime"
                          }
                          Text {
                              id: onNumChangedTimeText
                          }
                          Text {
                              text: "onCalledSlotTestTime"
                          }
                          Text {
                              id: onCalledSlotTestTimeText
                          }
                          Connections {
                              target: contentsRepeaterDelegate.target
                              function onNumChanged() {
                                  onNumChangedTimeText.text = new Date().toLocaleTimeString(Qt.locale(), "hh:mm:ss.zzz")
                              }
                              function onCalledSlotTest() {
                                  onCalledSlotTestTimeText.text = new Date().toLocaleTimeString(Qt.locale(), "hh:mm:ss.zzz")
                              }
                          }
                      }
                  }
              }
          }
      }
  }
  

The following warning will be displayed when executed.

2025-04-21 17:19:27.269 [37532] [21912] [warning] [qt.core.qobject.connect] - QObject::connect: No such slot TestNG::slotTest() in C:\work\projects\JVC\git\cannot-connect-to-slot\main\testNG.h:31
2025-04-21 17:19:27.879 [37532] [21912] [warning] [default] - QML Connections: Detected function "onNumChanged" in Connections element. This is probably intended to be a signal handler but no signal of the target matches the name.
2025-04-21 17:19:27.879 [37532] [21912] [warning] [default] - QML Connections: Detected function "onCalledSlotTest" in Connections element. This is probably intended to be a signal handler but no signal of the target matches the name.
2025-04-21 17:19:27.881 [37532] [21912] [warning] [default] - Unable to assign [undefined] to QString
2025-04-21 17:19:41.881 [37532] [21912] [warning] [default] - TypeError: Value is null and could not be converted to an object

The issue seems to be that the created moc does not contain items enabled with `__has_include`.

• moc_testNG.cpp

  /****************************************************************************
  ** Meta object code from reading C++ file 'testNG.h'
  **
  ** Created by: The Qt Meta Object Compiler version 68 (Qt 6.8.3)
  **
  ** WARNING! All changes made in this file will be lost!
  *****************************************************************************/
  
  #include "../../../../../../cannot-connect-to-slot/main/testNG.h"
  #include <QtCore/qmetatype.h>
  
  #include <QtCore/qtmochelpers.h>
  
  #include <memory>
  
  
  #include <QtCore/qxptype_traits.h>
  #if !defined(Q_MOC_OUTPUT_REVISION)
  #error "The header file 'testNG.h' doesn't include <QObject>."
  #elif Q_MOC_OUTPUT_REVISION != 68
  #error "This file was generated using the moc from 6.8.3. It"
  #error "cannot be used with the include files from this version of Qt."
  #error "(The moc has changed too much.)"
  #endif
  
  #ifndef Q_CONSTINIT
  #define Q_CONSTINIT
  #endif
  
  QT_WARNING_PUSH
  QT_WARNING_DISABLE_DEPRECATED
  QT_WARNING_DISABLE_GCC("-Wuseless-cast")
  namespace {
  struct qt_meta_tag_ZN6TestNGE_t {};
  } // unnamed namespace
  
  
  #ifdef QT_MOC_HAS_STRINGDATA
  static constexpr auto qt_meta_stringdata_ZN6TestNGE = QtMocHelpers::stringData(
      "TestNG"
  );
  #else  // !QT_MOC_HAS_STRINGDATA
  #error "qtmochelpers.h not found or too old."
  #endif // !QT_MOC_HAS_STRINGDATA
  
  Q_CONSTINIT static const uint qt_meta_data_ZN6TestNGE[] = {
  
  // content:
      12,       // revision
      0,       // classname
      0,    0, // classinfo
      0,    0, // methods
      0,    0, // properties
      0,    0, // enums/sets
      0,    0, // constructors
      0,       // flags
      0,       // signalCount
  
      0        // eod
  };
  
  Q_CONSTINIT const QMetaObject TestNG::staticMetaObject = { {
      QMetaObject::SuperData::link<QObject::staticMetaObject>(),
      qt_meta_stringdata_ZN6TestNGE.offsetsAndSizes,
      qt_meta_data_ZN6TestNGE,
      qt_static_metacall,
      nullptr,
      qt_incomplete_metaTypeArray<qt_meta_tag_ZN6TestNGE_t,
          // Q_OBJECT / Q_GADGET
          QtPrivate::TypeAndForceComplete<TestNG, std::true_type>
      >,
      nullptr
  } };
  
  void TestNG::qt_static_metacall(QObject *_o, QMetaObject::Call _c, int _id, void **_a)
  {
      auto *_t = static_cast<TestNG *>(_o);
      (void)_t;
      (void)_c;
      (void)_id;
      (void)_a;
  }
  
  const QMetaObject *TestNG::metaObject() const
  {
      return QObject::d_ptr->metaObject ? QObject::d_ptr->dynamicMetaObject() : &staticMetaObject;
  }
  
  void *TestNG::qt_metacast(const char *_clname)
  {
      if (!_clname) return nullptr;
      if (!strcmp(_clname, qt_meta_stringdata_ZN6TestNGE.stringdata0))
          return static_cast<void*>(this);
      return QObject::qt_metacast(_clname);
  }
  
  int TestNG::qt_metacall(QMetaObject::Call _c, int _id, void **_a)
  {
      _id = QObject::qt_metacall(_c, _id, _a);
      return _id;
  }
  QT_WARNING_POP