I deployed this smartcontract few months ago and it was running perfectly well but when I compiled it today, suddenly 4 errors are coming and I am very frustrated how to resolve them. Can anyone correct the errors here.
Here is my smartcontract
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
contract FractionalNFT is ERC721, ERC721Enumerable, ERC721URIStorage, Pausable, Ownable, ERC721Burnable {
using Counters for Counters.Counter;
Counters.Counter private _tokenIdCounter;
struct _fnft{
uint256 tokenId;
address fractionalToken;
}
mapping(uint256 => _fnft) public FNFT;
constructor() ERC721("FractionalNFT", "FNFT") {}
function safeMint(address to) public onlyOwner {
_safeMint(to, _tokenIdCounter.current());
_tokenIdCounter.increment();
}
function pause() public onlyOwner {
_pause();
}
function unpause() public onlyOwner {
_unpause();
}
function _baseURI() internal pure override returns (string memory) {
return "";
}
function _beforeTokenTransfer(address from, address to, uint256 tokenId)
internal
whenNotPaused
override(ERC721, ERC721Enumerable)
{
super._beforeTokenTransfer(from, to, tokenId);
}
function _burn(uint256 tokenId) internal override(ERC721, ERC721URIStorage) {
super._burn(tokenId);
}
function tokenURI(uint256 tokenId)
public
view
override(ERC721, ERC721URIStorage)
returns (string memory)
{
return super.tokenURI(tokenId);
}
function supportsInterface(bytes4 interfaceId)
public
view
override(ERC721, ERC721Enumerable)
returns (bool)
{
return super.supportsInterface(interfaceId);
}
//is the caller of this function the owner of the NFT?
modifier isNFTOwner(uint256 _tokenURI) {
require(msg.sender == ownerOf(_tokenURI));
_;
}
function transferFNFToken(
address _to,
uint256 _tokenURI,
uint256 _amount)
onlyOwner()
private
//isNFTOwner(_tokenURI)
{
FNFToken _fnftoken = FNFToken(FNFT[_tokenURI].fractionalToken);
_fnftoken.transfer(_to, _amount);
}
function mint(
address _to,
string memory tokenURI_,
uint256 _totalFractionalTokens
) external onlyOwner() {
_safeMint(_to, _tokenIdCounter.current());
_setTokenURI(_tokenIdCounter.current(), tokenURI_);
//Create a ERC20 Token Contract for this newly minted NFT
FNFToken _fnftoken = (new FNFToken)(); //initialize
_fnftoken.mint(msg.sender, _totalFractionalTokens * 1000000000000000000); //now mint the fractional tokens and send it to the owner of this NFT
_fnft memory fnft; //constructor
fnft.tokenId = _tokenIdCounter.current();
fnft.fractionalToken = address(_fnftoken);
FNFT[_tokenIdCounter.current()] = fnft; //bind the fractional token address to this NFT token just minted
_tokenIdCounter.increment();
}
}
contract FNFToken is ERC20, ERC20Burnable, Ownable {
constructor() ERC20("FNFToken", "FNT") {}
function mint(address to, uint256 amount) public onlyOwner {
_mint(to, amount);
}
}