Behaviour of QStandardItem::setItemData() is inconsistent with QAbstractItemModel::setItemData()

Documentation for QAbstractItemModel::setItemData() states:

Roles that are not in roles will not be modified.

However, QStandardItemModel's reimplementation uses QStandardItem::setItemData(), which replaces the existing values with the new values:

if (values!=newValues)

{ values=newValues; if (model) model->d_func()->itemChanged(q); }

So the behaviour is inconsistent.