Frax Ether Liquid Staking contest - Pheonix's results

If a variable is not set/initialized, it is assumed to have the default value (0 for uint, false for bool, address(0) for address…). Explicitly initializing it with its default value is an anti-pattern and wastes gas.

As an example: for (uint256 i = 0; i < numIterations; ++i) { should be replaced with for (uint256 i; i < numIterations; ++i) {

Affected code :

1. ( frxETHMinter.sol)

    // Give each deposit chunk to an empty validator
    for (uint256 i = 0; i < numDeposits; ++i) {
        // Get validator information
        (

2. OperatorRegistery.sol

// Fill the new validators array with all except the value to remove

        for (uint256 i = 0; i < original_validators.length; ++i) {
            if (i != remove_idx) {
                validators.push(original_validators[i]);
            }
        

3. OperatorRegistery.sol

/// @notice Remove validators from the end of the validators array, in case they were added in error

function popValidators(uint256 times) public onlyByOwnGov {
    // Loop through and remove validator entries at the end
    for (uint256 i = 0; i < times; ++i) {
        validators.pop();
    }

4. OperatorRegistery.sol

/// @notice Add multiple new validators in one function call

/** @dev You should verify offchain that the validators are indeed valid before adding them
    Reason we don't do that here is for gas */
function addValidators(Validator[] calldata validatorArray) external onlyByOwnGov {
    uint arrayLength = validatorArray.length;
    for (uint256 i = 0; i < arrayLength; ++i) {
        addValidator(validatorArray[i]);
    }
}    

5. ERC20PermitPermissionedMint.sol

// 'Delete' from the array by setting the address to 0x0

    for (uint i = 0; i < minters_array.length; i++){ 
        if (minters_array[i] == minter_address) {
            minters_array[i] = address(0); // This will leave a null in the array and keep the indices the same
            break;
        }
    }