anchor.diff:      constructor() ERC20("MyToken", "TKN") {
           // Grant the contract deployer the default admin role: it will be able
           // to grant and revoke any roles
  -        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
  +        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
       }
   
       function mint(address to, uint256 amount) public onlyRole(MINTER_ROLE) {
  
positive.code: 
      constructor(address minter) ERC20("MyToken", "TKN") {
          // Grant the minter role to a specified account
          _setupRole(MINTER_ROLE, minter);
      }
  
      function mint(address to, uint256 amount) public {
  
negative.code:     bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
  
      constructor(address minter, address burner) ERC20("MyToken", "TKN") {
          _grantRole(MINTER_ROLE, minter);
          _grantRole(BURNER_ROLE, burner);
      }
  
      function mint(address to, uint256 amount) public onlyRole(MINTER_ROLE) {
  