QStyledItemDelegate and index.isValid() assert

In QStyleItemDelegate on line 367 you have assert for invalid index. Maybe it's needed.

But I have a following use case:

void
WordWrapItemDelegate::paint( QPainter * painter,
    const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
    QStyledItemDelegate::paint( painter, option, QModelIndex() ); 

    painter->drawText( option.rect,
        Qt::AlignLeft | Qt::TextWordWrap | Qt::AlignVCenter,
        index.data( Qt::DisplayRole ).toString() );
} 

As you can see I draw everything with QStyledItemDelegate, but text I draw manually. To draw everything without data I pass QModelIndex() to QStyledItemDelegate:paint(). And in debug build this leads to assert dialog.

Could you clarify your opinion to dissallow invoke paint() method with invalid index in QStyledItemDelegate?

My use case, as I guess, is very common...