Gas Optimizations

[code423n4]

1. Use Custom Error instead of Revert String to Save Gas

Custom error from solidity 0.8.4 are cheaper than revert strings, custom error are defined using the error statement can use inside and outside the contract.

source https://blog.soliditylang.org/2021/04/21/custom-errors/

i suggest replacing revert error strings with custom error

POC :

https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashLogic.sol#L57
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashLogic.sol#L122
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashLogic.sol#L211
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashLogic.sol#L225
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashBase.sol#L37
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashBase.sol#L42
https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashERC4626.sol#L23

2. > 0 is less efficient than != 0 for unsigned integers

!= 0 costs less gas compared to > 0 for unsigned integers in require statements with the optimizer enabled (6 gas)

While it may seem that > 0 is cheaper than !=, this is only true without the optimizer enabled and outside a require statement. If you enable the optimizer at 10k AND you’re in a require statement, this will save gas.

source : https://twitter.com/gzeon/status/1485428085885640706

I suggest changing > 0 with != 0

POC :

https://github.com/code-423n4/2022-06-notional-coop/blob/main/notional-wrapped-fcash/contracts/wfCashERC4626.sol#L23