Y2k Finance contest - tnevler's results

Report

Gas Optimizations

[G-01]: X += Y costs more gas than X = X + Y

Context:

https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/VaultFactory.sol#L195

Recommendation:

Change X += Y (X -= Y) to X = X + Y (X = X - Y).

[G-02]: Don't initialize variable with its default value

Context:

https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/Vault.sol#L443

Description:

Default value of uint is 0. It's unnecessary and costs more gas to initialize uint variavles to 0.

Recommendation:

Change uint256 i = 0; to uint256 i;

[G-03]: >0 costs more gas than !=0

Context:

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/StakingRewards.sol#L119 uint256

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/StakingRewards.sol#L134 uint256

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/Vault.sol#L187

Description:

uint type and msg.value are always non-negative.

Recommendation:

Change >0 to !=0.

[G-04]: Use new variable instead of calling function and reading array length in every loop of a for-loop

Context:

for (uint256 i = 0; i < epochsLength(); i++) {

https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/Vault.sol#L443

Description:

If you call function and read the length of the array at each iteration of the loop, this consumes a lot of gas.

Recommendation:

Store the array’s length in a variable before the for-loop, and use this new variable in the loop.

[G-05]: i++ costs more gas than ++i

Context:

https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/Vault.sol#L443

Recommendation:

Change i++ to ++i.

[G-06]: variable can be immutable

Context:

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/RewardsFactory.sol#L9

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/RewardsFactory.sol#L10

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/RewardsFactory.sol#L11

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/rewards/StakingRewards.sol#L41

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/SemiFungibleVault.sol#L21

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/oracles/PegOracle.sol#L10

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/oracles/PegOracle.sol#L11

• https://github.com/code-423n4/2022-09-y2k-finance/blob/main/src/oracles/PegOracle.sol#L13

Description:

Variable is set in the constructor and never modified after that.

Recommendation:

It is more gas efficient to mark it as immutable.