Function beforeTokenTransfer

Hello everybody,

I m new here and in Solidity and I try to learn. I have an issue with this function (_beforeTokenTransfer), here is the code :

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract SoulboundToken is ERC721 {
uint256 public nextTokenId;

mapping(uint256 => bool) public soulbound;

constructor() ERC721("SoulboundToken", "MTK") {}

function mint(address to) public {
    _mint(to, nextTokenId);
    soulbound[nextTokenId] = true;
    nextTokenId++;
}

// Override the transfer functions to prevent transferring of SBTs
function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal override {
    require(from == address(0), "SBTs are non-transferable");
    super._beforeTokenTransfer(from, to, tokenId);
}

}

Remix or VScode send me an error : "Function has override specified but does not override anything"

I don't understand why and how can I fix it

Could you please help me e-and explain me what to do and what is the matter ?

Thank you very much

William

Start by checking the OpenZeppelin Contracts version used by the import, then compare its ERC721 transfer-hook signature with the _beforeTokenTransfer override shown in the issue. Confirm the version-compatible extension point and verify that the SoulboundToken example compiles in Remix or VSCode without the override error.