Changing bool to uint256 can save gas

[code423n4]

Handle

WatchPug

Vulnerability details

Booleans are more expensive than uint256 or any type that takes up a full word because each write operation emits an extra SLOAD to first read the slot's contents, replace the bits taken up by the boolean, and then write back. This is the compiler's defense against contract upgrades and pointer aliasing, and it cannot be disabled.

See: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/security/ReentrancyGuard.sol#L23-L27

https://github.com/livepeer/arbitrum-lpt-bridge/blob/ebf68d11879c2798c5ec0735411b08d0bea4f287/contracts/L2/gateway/L2Migrator.sol#L51-L51

    bool public claimStakeEnabled;

https://github.com/livepeer/arbitrum-lpt-bridge/blob/ebf68d11879c2798c5ec0735411b08d0bea4f287/contracts/L2/gateway/L2Migrator.sol#L53-L57

    mapping(address => bool) public migratedDelegators;
    // mapping(address => address) public delegatorPools;
    // mapping(address => uint256) public claimedDelegatedStake;
    mapping(address => mapping(uint256 => bool)) public migratedUnbondingLocks;
    mapping(address => bool) public migratedSenders;

[yondonfu]

Likely won't change as we think keeping booleans is more readable.