I’m trying to use the default Qfontcombobox in my qt app to change the font of a text edit, and i am getting this error for some reason.
Here is my definition for my mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    connect(ui->fontComboBox,&QFontComboBox::currentFontChanged,this,&MainWindow::fontChanged);
}
void MainWindow::fontChanged(QFont &f) {
    ui->textEdit->setFont(f);
}
MainWindow::~MainWindow()
{
    delete ui;
}

and here is the code for the mainwindow header

#include <QMainWindow>
#include <QComboBox>
#include <QObject>

QT_BEGIN_NAMESPACE
namespace Ui {
class MainWindow;
}
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

public slots:
    void fontChanged(QFont &f);
private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

Thank you