#include <QApplication>
#include <QWidget>
#include <QMouseEvent>

struct MyWidget3:QWidget{
	using QWidget::QWidget;//inherit constructors
	void mousePressEvent(QMouseEvent *event){
		this->hide();
		this->deleteLater();//`delete this;` or `this->destroy();` also crash
	}
};

struct MyWidget2:QWidget{
	using QWidget::QWidget;//inherit constructors
	void mousePressEvent(QMouseEvent *event){
		MyWidget3 *w3=new MyWidget3(nullptr,Qt::Window);
		w3->setAttribute(Qt::WA_DeleteOnClose);//delete this line if you want memory leak
		w3->setWindowTitle("click me (MyWidget3)");
		w3->setWindowModality(Qt::ApplicationModal);
		w3->show();
	}
};

struct MyWidget1:QWidget{
	using QWidget::QWidget;//inherit constructors
	void mousePressEvent(QMouseEvent *event){
		MyWidget2 *w2=new MyWidget2(nullptr,Qt::Window);
		w2->setAttribute(Qt::WA_DeleteOnClose);//delete this line if you want memory leak
		w2->setWindowTitle("click me (MyWidget2)");
		w2->setWindowModality(Qt::ApplicationModal);
		w2->show();
	}
};

int main(int argc,char **argv){
	QApplication a(argc,argv);
	MyWidget1 w1(nullptr,Qt::Window);
	w1.setWindowTitle("click me (MyWidget1)");
	w1.show();
	a.exec();
}

g++ \
cppcrash.cpp \
-o cppcrash \
-O0 \
-ggdb \
-I/usr/include/x86_64-linux-gnu/qt6 \
-I/usr/include/x86_64-linux-gnu/qt6/QtWidgets \
-I/usr/include/x86_64-linux-gnu/qt6/QtGui \
-I/usr/include/x86_64-linux-gnu/qt6/QtCore \
-lQt6Core \
-lQt6Gui \
-lQt6Widgets

./cppcrash