When a modal dialog is shown on top of another one and then if application exits it will cause a crash

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   org.qt-project.QtGui          	0x00000001065f1658 QWindow::handle() const + 8
1   org.qt-project.QtWidgets      	0x0000000105ede52a QApplicationPrivate::isWindowBlocked(QWindow*, QWindow**) const + 266
2   org.qt-project.QtGui          	0x00000001065df105 QGuiApplicationPrivate::hideModalWindow(QWindow*) + 149
3   org.qt-project.QtGui          	0x00000001065ee08e QWindow::setVisible(bool) + 1006
4   org.qt-project.QtWidgets      	0x0000000105f1d58f QWidgetPrivate::hide_sys() + 335
5   org.qt-project.QtWidgets      	0x0000000105f1ec7a QWidgetPrivate::hide_helper() + 186
6   org.qt-project.QtWidgets      	0x0000000105f1f0ec QWidget::setVisible(bool) + 284
7   org.qt-project.QtWidgets      	0x00000001060dfef0 QDialog::setVisible(bool) + 368
8   org.qt-project.QtWidgets      	0x00000001060deec3 QDialog::~QDialog() + 35
9   org.qt-project.QtCore         	0x0000000106e1868d QObjectPrivate::deleteChildren() + 221
10  org.qt-project.QtWidgets      	0x0000000105f0f582 QWidget::~QWidget() + 1458
11  Digia.qtbug54566              	0x0000000105ebaf4a MainWindow::~MainWindow() + 90 (mainwindow.cpp:22)
12  Digia.qtbug54566              	0x0000000105ebaf65 MainWindow::~MainWindow() + 21 (mainwindow.cpp:22)
13  Digia.qtbug54566              	0x0000000105ebafa9 MainWindow::~MainWindow() + 25 (mainwindow.cpp:20)
14  Digia.qtbug54566              	0x0000000105ebc5a1 tApplication::~tApplication() + 65 (tApplication.cpp:17)
15  Digia.qtbug54566              	0x0000000105ebc5d5 tApplication::~tApplication() + 21 (tApplication.cpp:17)
16  Digia.qtbug54566              	0x0000000105ebadca main + 74 (main.cpp:9)
17  Digia.qtbug54566              	0x0000000105ebad74 start + 52