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

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();
}