Declare keccak variables as immutable

[code423n4]

Handle

pmerkleplant

Vulnerability details

Impact

Access roles marked as constant results in computing the keccak operation
each time the variables are used, which increases gas costs.

Changing the variables to immutable results in computing the hash only
once on deployment, leading to gas savings.

For more information, see ethereum/solidity#9232 (comment).

The following declarations could be refactored:

./MovingAverage.sol:25:  bytes32 public constant UPDATER_ROLE = keccak256("UPDATER_ROLE");
./MaltDataLab.sol:28:  bytes32 public constant UPDATER_ROLE = keccak256("UPDATER_ROLE");
./Auction.sol:72:  bytes32 public constant AUCTION_AMENDER_ROLE = keccak256("AUCTION_AMENDER_ROLE");
./ERC20Permit.sol:16:  bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
./ERC20Permit.sol:17:  bytes32 public constant TRANSFER_TYPEHASH = keccak256("Transfer(address owner,address to,uint256 value,uint256 nonce,uint256 deadline)");
./Permissions.sol:17:  bytes32 public constant TIMELOCK_ROLE = keccak256("TIMELOCK_ROLE");
./Permissions.sol:18:  bytes32 public constant ADMIN_ROLE = keccak256("ADMIN_ROLE");
./Permissions.sol:19:  bytes32 public constant GOVERNOR_ROLE = keccak256("GOVERNOR_ROLE");
./Permissions.sol:22:  bytes32 public constant MONETARY_BURNER_ROLE = keccak256("MONETARY_BURNER_ROLE");
./Permissions.sol:23:  bytes32 public constant MONETARY_MINTER_ROLE = keccak256("MONETARY_MINTER_ROLE");
./Permissions.sol:26:  bytes32 public constant STABILIZER_NODE_ROLE = keccak256("STABILIZER_NODE_ROLE");
./Permissions.sol:27:  bytes32 public constant LIQUIDITY_MINE_ROLE = keccak256("LIQUIDITY_MINE_ROLE");
./Permissions.sol:28:  bytes32 public constant AUCTION_ROLE = keccak256("AUCTION_ROLE");
./Permissions.sol:29:  bytes32 public constant REWARD_THROTTLE_ROLE = keccak256("REWARD_THROTTLE_ROLE");
./AuctionParticipant.sol:15:  bytes32 public constant IMPLIED_COLLATERAL_SERVICE_ROLE = keccak256("IMPLIED_COLLATERAL_SERVICE_ROLE");
./AbstractRewardMine.sol:16:  bytes32 public constant REWARD_MANAGER_ROLE = keccak256("REWARD_MANAGER_ROLE");
./AbstractRewardMine.sol:17:  bytes32 public constant MINING_SERVICE_ROLE = keccak256("MINING_SERVICE_ROLE");
./MiningService.sol:20:  bytes32 public constant REINVESTOR_ROLE = keccak256("REINVESTOR_ROLE");
./MiningService.sol:21:  bytes32 public constant BONDING_ROLE = keccak256("BONDING_ROLE");
./RewardSystem/RewardDistributor.sol:36:  bytes32 public constant THROTTLER_ROLE = keccak256("THROTTLER_ROLE");
./RewardSystem/RewardDistributor.sol:37:  bytes32 public constant REWARD_MINE_ROLE = keccak256("REWARD_MINE_ROLE");
./RewardSystem/RewardDistributor.sol:38:  bytes32 public constant FOCAL_LENGTH_UPDATER_ROLE = keccak256("FOCAL_LENGTH_UPDATER_ROLE");
./DexHandlers/UniswapHandler.sol:24:  bytes32 public constant BUYER_ROLE = keccak256("BUYER_ROLE");

Tools used

grep -rn "keccak256(" .

[GalloDaSballo]

Finding is invalid as per: https://twitter.com/TomFrench_eth/status/1476940064122826756