Before actually deleting QTreeWidgetItems from QTree{Model,Widget{,Item}} dtors,
their 'view' members need to be set to nullptr, lest they attempt to delist
themselves from the list of top-level items.
For the QTreeModel::headerItem, this was forgottten.
Found by UBSan:
qtreewidget.cpp:1488:70: runtime error: member call on address 0x7ffd843dd470 which does not point to an object of type 'QAbstractItemView'
0x7ffd843dd470: note: object is of type 'QWidget'
#0 0x2b83d5b48323 in QTreeWidgetItem::~QTreeWidgetItem() src/widgets/itemviews/qtreewidget.cpp:1488
#1 0x2b83d5b48860 in QTreeWidgetItem::~QTreeWidgetItem() src/widgets/itemviews/qtreewidget.cpp:1535
#2 0x2b83d5b41659 in QTreeModel::~QTreeModel() src/widgets/itemviews/qtreewidget.cpp:143
#3 0x2b83d5b41bc0 in QTreeModel::~QTreeModel() src/widgets/itemviews/qtreewidget.cpp:146
#4 0x2b83df220747 in QObjectPrivate::deleteChildren() src/corelib/kernel/qobject.cpp:2010
#5 0x2b83d4603dd0 in QWidget::~QWidget() src/widgets/kernel/qwidget.cpp:1675
#6 0x2b83d4d76066 in QFrame::~QFrame() src/widgets/widgets/qframe.cpp:256
#7 0x2b83d5270442 in QAbstractScrollArea::~QAbstractScrollArea() src/widgets/widgets/qabstractscrollarea.cpp:575
#8 0x2b83d5733eb9 in QAbstractItemView::~QAbstractItemView() src/widgets/itemviews/qabstractitemview.cpp:617
#9 0x2b83d598b216 in QTreeView::~QTreeView() src/widgets/itemviews/qtreeview.cpp:206
#10 0x2b83d5b218b6 in QTreeWidget::~QTreeWidget() src/widgets/itemviews/qtreewidget.cpp:2549
#11 0x4eef42 in tst_QTreeWidgetItemIterator::updateIfModifiedFromWidget() tests/auto/widgets/itemviews/qtreewidgetitemiterator/tst_qtreewidgetitemiterator.cpp:1089
Change-Id: I57c277adee8c99eb07b274d6d8ea1f6fbf3575be
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
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