I'm extending the \Magento\Catalog\Block\Product\View file in AddToCart.php.
In my AddTocart, I've added this line :
$stock = $this->isInStockCustom($sku);
Now, I'm adding options to my products. It was working find until now.
But if I add an option to this product, in my log, I have this
Invalid method Magento\Catalog\Block\Product\View\Interceptor::isInStockCustom  
But if I remove the options, I don't have this error anymore.
Any help would be very appreciated.