Reducing row/col span in QTableView results in assert at line 118 of qtableview.cpp

To reproduce, use something like this on a QTableView:-

ui.setupUi(this);
mModel = new QStandardItemModel(6,6,this);

for (int row = 0; row < 6; ++row) {
for (int column = 0; column < 6; ++column)

{ QStandardItem *item = new QStandardItem(QString("row %0, column %1").arg(row).arg(column)); mModel->setItem(row, column, item); }

}
ui.tableView->setModel(mModel);
ui.tableView->setSpan( 0, 0, 2, 2 );
ui.tableView->setSpan( 0, 0, 1, 1 );

When the span is reduced for the item at 0,0 the ASSERT occurs.

This seems to be a regression as it does not reproduce using Qt 4.5.3