"Static polymorphism with Qt signal/slot: What is wrong?" - c++

Question

I'm trying to use static polymorphism instead of dynamics polymorphism with Qt signal/slot mechanism. But I get compile error. What is wrong in my code? What is workaround?
devices.h
#ifndef DEVICES_H
#define DEVICES_H
#include <QtCore>
#include <qdebug.h>
class DeviceController : public QObject
{
Q_OBJECT
public:
explicit DeviceController(QObject *parent = nullptr):QObject(parent){}
virtual ~DeviceController() {}
void doAllDevicesInit(){
emit deviceAInitSignal();
}
signals:
void deviceAInitSignal();
};
template<typename T> class BaseDevice {
public:
void init() {
static_cast<T*>(this)->doInit();
qDebug() << QString("BaseDevice initialized!");
}
};
class DeviceA : public BaseDevice<DeviceA> {
public:
void doInit() {
qDebug() << "DeviceA initialized!";
}
};
#endif // DEVICES_H
main.cpp
#include "devices.h"
int main(int argc, char *argv[])
{
Q_UNUSED(argc);Q_UNUSED(argv);
DeviceA deviceA;
DeviceController deviceController;
QObject::connect(&deviceController,&DeviceController::deviceAInitSignal,
&deviceA, &DeviceA::init);
deviceController.doAllDevicesInit();
return 0;
}
Compile output
Qt5.12.2/5.12.2/gcc_64/include/QtCore/qobjectdefs_impl.h:414:94:
error: invalid static_cast from type ‘QObject*’ to type
‘QtPrivate::FunctionPointer::*)()>::Object*’
{aka ‘BaseDevice*’}
FuncType::template call(static_cast(this_)->function, static_cast(r), a);

Answer 1

Thanks to drescherjm comment, a workaround is as follow
devices.h
...
template<typename T>
class BaseDevice: public QObject {
//Q_OBJECT, Error: Template classes not supported by Q_OBJECT
public:
explicit BaseDevice(QObject *parent = nullptr):QObject(parent){}
virtual ~BaseDevice() {}
void init() {
static_cast<T*>(this)->doInit();
qDebug() << QString("BaseDevice initialized!");
}
};
class DeviceA : public BaseDevice<DeviceA> {
Q_OBJECT
public:
explicit DeviceA(QObject *parent = nullptr):BaseDevice<DeviceA>(parent){}
virtual ~DeviceA() {}
void doInit() {
qDebug() << "DeviceA initialized!";
}
};
#endif // DEVICES_H