Solidity related question when i change compiler version 0.8 then through error

Question

by using solidity compiler 0.8 through Explicit type conversion not allowed from "address" to "uint256".

for (uint idx = 0; idx < v.length; idx++){
            address signer = ecrecover(signedHash, v[idx], r[idx], s[idx]);
            require(admins[signer]);
            require(uint256(signer) > uint256(lastVoter));
            lastVoter = signer;
            emit NewCheckpointVote(_sectionIndex, _hash, v[idx], r[idx], s[idx]);

            // Sufficient signatures present, update latest checkpoint.
            if (idx+1 >= threshold){
                hash = _hash;
                height = block.number;
                sectionIndex = _sectionIndex;
                return true;
            }
        }
        // We shouldn't wind up here, reverting un-emits the events
        revert();
    }