How To Refresh List of Auto Complete Suggestions in PyQt5 LineEdit Widget

I am using QCompleter to populate a QLineEdit widget lineEdit1 with a list of auto completions autocomplete_list. The widget successfully populates with the data in autocomplete list.

However when I enter the any of the following text into lineEdit1:

a
a1
a2
a3
a4
a5

And presss return, I get the following error message:

Process finished with exit code -1073741819 (0xC0000005)

What is happening here? The program doesn't crash when I enter 'b' into the widget. It is also fine when I enter '1' into the widget. Why does it crash when I enter 'a' or any of the 5 items in autocomplete_list?

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):

    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def setupData(self):

        self.lineEdit1 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit1.setObjectName("lineEdit1")
        self.lineEdit1.returnPressed.connect(self.return_pressed)
        self.autocomplete_list = ['a1', 'a2', 'a3', 'a4', 'a5']
        self.completer = QtWidgets.QCompleter(self.autocomplete_list)
        self.lineEdit1.setCompleter(self.completer)


    def return_pressed(self):
        user_input = self.lineEdit1.text()
        updated_list = [x for x in self.autocomplete_list if x not in user_input]
        print(updated_list)
        self.completer = QtWidgets.QCompleter(updated_list)
        self.lineEdit1.setCompleter(self.completer)
        print('Gets to here')


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    ui.setupData()
    MainWindow.show()
    sys.exit(app.exec_())

I have tested logic in C++ yourself and I don't see any errors which I can suppose the error is caused by the sip wrapper that keeps a reference to the pointer of the old QCompleter that is removed from memory when you establish a new QCompleter generating a Segmentation fault ( core dumped).

On the other hand, your methodology is not very elegant, I prefer to use a model to handle the information and then only remove the items in a simple way.

def setupData(self):

    self.lineEdit1 = QtWidgets.QLineEdit(self.centralwidget)
    self.lineEdit1.setObjectName("lineEdit1")
    self.lineEdit1.returnPressed.connect(self.return_pressed)
    autocomplete_list = ['a1', 'a2', 'a3', 'a4', 'a5']

    self.autocomplete_model = QtGui.QStandardItemModel()
    for text in autocomplete_list:
        self.autocomplete_model.appendRow(QtGui.QStandardItem(text))

    self.completer = QtWidgets.QCompleter()
    self.completer.setModel(self.autocomplete_model)
    self.lineEdit1.setCompleter(self.completer)


def return_pressed(self):
    user_input = self.lineEdit1.text()
    items = self.autocomplete_model.findItems(user_input, QtCore.Qt.MatchContains)
    for item in items:
        self.autocomplete_model.takeItem(item.row())