MailsFoldersManager::processDelete

private function processDelete($folderTrashName, $deleteImmediately = false)
{
	$messagesToMove = $messagesToDelete = [];

	foreach ($this->messages as $messageUid)
	{
		if ($this->isMailToBeDeleted($messageUid) || $deleteImmediately)
		{
			$messagesToDelete[] = $messageUid;
		}
		else
		{
			$messagesToMove[] = $messageUid;
		}
	}

	$result = $this->processMoving($messagesToMove, $folderTrashName);
	if (!$result->isSuccess())
	{
		return (new MainResult())->addError(new MainError(Loc::getMessage('MAIL_CLIENT_SYNC_ERROR'), 'MAIL_CLIENT_SYNC_ERROR'));
	}

	return $this->deleteMessages($messagesToDelete, $this->mailbox);
}