Signal not found error solved by using old connect sythax. Why?

[nwoki]

Hi all!

As the title says, I've encountered a problem with Qt's signal/slots. I have a QQmlExtensionPlugin (Exercise) where I need to connect to its own signals in order to start/stop a timer. Now, I wanted to do it like I've been doing for some time now, with:

connect(this, &Exercise::statusChanged, this, &Exercise::startStopElapsedPausedTimer);

NOTE: arguments match (there aren't any)

but I encountered the following error during runtime:

QObject::connect: signal not found in Exercise
QObject::connect: signal not found in Exercise

After banging my head around and checking my code, I tried to change the signal/slot synthax with the following:

connect(this, SIGNAL(statusChanged()), this, SLOT(startStopElapsedPausedTimer()));

et voilà! No more connection error at runtime. Can anyone explain this to me? What's happening here? The wiki doesn't say anything about behaviour changes when adopting the new sythax

[VRonin]

could you show the definition of Exercise?

[nwoki]

The QQmlExtensionPlugin

.h

#ifndef EXERCISESETTINGSPLUGIN_H
#define EXERCISESETTINGSPLUGIN_H

#include <QtQml/QQmlExtensionPlugin>

class Q_DECL_EXPORT ExerciseSettingsPlugin : public QQmlExtensionPlugin
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID QQmlExtensionInterface_iid)

public:
    void registerTypes(const char *uri);
};

#endif // EXERCISESETTINGSPLUGIN_H

.cpp

#include "exercise.h"
#include "exercisesettingsplugin.h"

#include <QtQml/QQmlComponent>

void ExerciseSettingsPlugin::registerTypes(const char *uri)
{
    int versionMajor = 0;
    int versionMinor = 1;

    Q_UNUSED (versionMajor);
    Q_UNUSED (versionMinor);

    Q_ASSERT(uri == QLatin1String("nirvana.qml.exercisesettings"));
    qmlRegisterType<Exercise>(uri, versionMajor, versionMinor, "Exercise");
}

and Exercise .h

#ifndef EXERCISE_H
#define EXERCISE_H

#include <QtCore/QObject>

class Q_DECL_EXPORT Exercise : public QObject
{
    Q_OBJECT

    // list of properties

public:
    Exercise(QObject *parent = 0);
    Exercise(Exercise *ex);
    virtual ~Exercise();


Q_SIGNALS:
    void statusChanged();

private Q_SLOTS:
    void startStopElapsedPausedTimer();

private:
    void setupTimerConnections();


    class Private;
    Private * const d;
};

#endif // EXERCISE_H