QueryChainElement::isBackReference

public function isBackReference()
{
	if ($this->type === 3)
	{
		return true;
	}

	if ($this->value instanceof ExpressionField)
	{
		foreach ($this->value->getBuildFromChains() as $bfChain)
		{
			if ($bfChain->hasBackReference())
			{
				return true;
			}
		}
	}

	return false;
}