Magento – Error during compilation after upgrade in magento 2.2.3

Try with below code,

Remove var folder and run command of compile,

class BuyingListIndex extends \Magento\Framework\View\Element\Template {
    public function __construct(
    \Magento\Framework\View\Element\Template\Context $context,
    \Custom\Module\Model\ResourceModel\Posts\CollectionFactory $collectionFactory, 
    \Custom\Module\Model\Posts $posts,
    \Magento\Framework\Image\AdapterFactory $imageFactory,
    array $data = []
    ) {
        $this->collectionFactory = $collectionFactory;
        $this->posts = $posts;
        $this->_filesystem = $context->getFilesystem();
        $this->_imageFactory = $imageFactory;
        $this->scopeConfig = $context->getScopeConfig();
         parent::__construct($context, $data);
    }
}

This is because your parent constructor has redundant arguments or not correct . In your case, need to remove arguments: $storeManager and $metadataPool.

app\code\Custom\Module\Model\ResourceModel\Posts\Grid\Collection.php

parent::__construct(
        $entityFactory,
        $logger,
        $fetchStrategy,
        $eventManager,
        //$storeManager, <= Remove it
        //$metadataPool, <= Remove it
        $connection,
        $resource
    );