compilerMetadata is modifyingartifacts/NFTContract.json

Solidity Programming
#1

I’m getting this error " compilerMetadata is modifyingartifacts/NFTContract.json" when trying to compile this smart contract in Remix:

pragma solidity ^0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC1155/ERC1155.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";

contract NFTContract is ERC1155, Ownable {
    uint256 public constant ARTWORK = 0;
    uint256 public constant PHOTO = 1;
    
    constructor() ERC1155("") {
        _mint(msg.sender, ARTWORK, 1, "");  
        _mint(msg.sender, PHOTO, 2, "");  
    }
    
    function mint(address account, uint256 id, uint256 amount) public onlyOwner {
        _mint(account, id, amount, "");
    }
    
    function burn(address account, uint256 id, uint256 amount) public {
        require(msg.sender == account);
        _burn(account, id, amount);
    }
}

Exactly the same code worked yesterday so maybe it’s an IDE bug?

#2

I think that it only says that it is going to override previous build files.

#3

Yes, but it does not compile after that. One more waring I’m seeing is this:

"Warning: SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing “SPDX-License-Identifier: " to each source file. Use “SPDX-License-Identifier: UNLICENSED” for non-open-source code. Please see https://spdx.org for more information.
–> opensea_nft.sol”

#4

You could try to create a new contract with same code and compile it.