Solidity - How to set to null or empty a payable address

Question

I am quite new to solidity and I have the following situation: I have this struct

struct Item {
    uint    sku;  
    uint    upc;
    address ownerID;  
    address originProducerID; 
    string  originProducerName;
    string  originProducerInformation; 
    uint    productId;  
    string  productNotes; 
    uint    productPrice;
    State   itemState;  
    address payable consumerID; 
}

In the last one (consumerID) I had to make it payable for this (I need to use transfer):

modifier checkValue(uint _upc) {
    _;
    uint _price = items[_upc].productPrice;
    uint amountToReturn = msg.value - _price;
    items[_upc].consumerID.transfer(amountToReturn);
}

The problem is when I try to create an item, I need to set that value to what it would be null or empty.

function collectMaterials(address _originProducerId, string memory _originProducerName, string memory _originProducerInformation, uint _productId, string memory _productNotes, uint _productPrice) public 
{
    items[sku] = Item(
        {
            sku: sku, 
            upc: upc,
            ownerID: msg.sender, 
            originProducerID: msg.sender, 
            originProducerName: _originProducerName, 
            originProducerInformation: _originProducerInformation, 
            productId: sku + upc, 
            productNotes: _productNotes, 
            productPrice: _productPrice, 
            itemState: State.MaterialSelection, 
            consumerID: address(0)
        });

But I get this error

Invalid type for argument in function call. Invalid implicit conversion from address to address payable requested

How can I initialise that value to empty or null? Or is there a way to make it optional to add?

Thanks!

Answer 1

consumerID is of type address payable (an extension of the type address).

However, in the collectMaterials() function, you're passing type address as the value of consumerID.

Solution: Typecast the value 0 to address payable

consumerID: payable(address(0))