Nested Finance contest - Tomio's results

1. considered using require instead of && can save gas https://github.com/code-423n4/2022-02-nested/blob/main/contracts/FeeSplitter.sol#L123 // gas cost 35473

Change to:

require(accountsLength != 0);
require (accountsLength == _weights.length, "FS: INPUTS_LENGTH_MUST_MATCH");

// gas cost 35465

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2. considered add unchecked can save gas https://github.com/code-423n4/2022-02-nested/blob/main/contracts/FeeSplitter.sol#L327 // gas cost 22798

add unchecked

unchecked {
return (_amount * _weight) / _totalWeights;
}

// gas cost 22440

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3. avoid unnecessary i = 0 because the default of uint is already 0 https://github.com/code-423n4/2022-02-nested/blob/main/contracts/FeeSplitter.sol#L126

considered removing 0 value can save gas

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4. SafeERC20 Gas Optimization https://github.com/code-423n4/2022-02-nested/blob/main/contracts/NestedFactory.sol#L19 by not declaring this

using SafeERC20 for IERC20;

and for example, use this:

SafeERC20.safeTransfer(IERC20(_inputToken)_msgSender(), _amountToSpend - amounts[1]);

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5. just read it directly to storage can save gas https://github.com/code-423n4/2022-02-nested/blob/main/contracts/FeeSplitter.sol#L279 // gas cost 24794

Change to:

Shareholder[] storage shareholdersCache = shareholders;

// gas cost 24684

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6. the original function will return 0 which a default value for uint256 https://github.com/code-423n4/2022-02-nested/blob/main/contracts/FeeSplitter.sol#L216 // gas cost 24940

Change to:

     function getAmountDue(address _account, IERC20 _token) public view returns (uint256) {
        TokenRecords storage _tokenRecords = tokenRecords[address(_token)];
        if (_tokenRecords.totalShares != 0) {

        uint256 totalReceived = _tokenRecords.totalReleased + _token.balanceOf(address(this));
        return
            (totalReceived * _tokenRecords.shares[_account]) /
            _tokenRecords.totalShares -
            _tokenRecords.released[_account];
        }
    }

// gas cost 24919

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