GAS: packing structs saves gas

[code423n4]

Handle

Ruhum

Vulnerability details

Impact

Structs should always be packed to save gas

Proof of Concept

• https://github.com/code-423n4/2021-12-yetifinance/blob/main/packages/contracts/contracts/PriceFeed.sol#L56

• https://github.com/code-423n4/2021-12-yetifinance/blob/main/packages/contracts/contracts/PriceFeed.sol#L64

• https://github.com/code-423n4/2021-12-yetifinance/blob/main/packages/contracts/contracts/Dependencies/Whitelist.sol#L28

Tools Used

none

Recommended Mitigation Steps

Pack structs, e.g.:

// unpacked, higher gas (6 storage slots):
    struct CollateralParams {
        uint256 ratio;
        address oracle;
        uint256 decimals;
        bool active;
        address priceCurve;
        uint256 index;
        bool isWrapped;
    }

// packed (needs 5 storage slots)
    struct CollateralParams {
        uint256 ratio;
        uint256 decimals;
        uint256 index;
        address oracle;
        bool active;
        address priceCurve;
        bool isWrapped;
    }

[kingyetifinance]

@LilYeti : Duplicate with #4 #5 and #6

[alcueca]

Taking as main