Tigris Trade contest - JC's results

---

summary

• G‑01 Multiple address/ID mappings can be combined into a single mapping of an address/ID to a struct, where appropriate | 18 instances
• G‑02 State variables that never change should be declared immutable or constant | 12 instances
• G-03 <x> += <y> costs more gas than <x> = <x> + <y> for state variables | 27 instances
• G-04 Not using the named return variables when a function returns, wastes deployment gas | 44 instances
• G-05 Use a more recent version of solidity | 22 instances

Total: 123 instances in 5 issues

---

[G‑01] Multiple address/ID mappings can be combined into a single mapping of an address/ID to a struct, where appropriate

Saves a storage slot for the mapping. Depending on the circumstances and sizes of types, can avoid a Gsset (20000 gas) per mapping combined. Reads and subsequent writes can also be cheaper when a function requires both values and they both fit in the same storage slot. Finally, if both fields are accessed in the same function, can save ~42 gas per access due to not having to recalculate the key’s keccak256 hash (Gkeccak256 - 30 gas) and that calculation’s associated stack operations.

Instances (18)

TradingExtension.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L17 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L18 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L19

Position.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L33 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L34 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L35 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L36 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L37 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L38

StableVault.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/StableVault.sol#L29 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/StableVault.sol#L30

Lock.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L18 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L19

BondNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L32 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L33 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L35 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L37 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L38

[G‑02] State variables that never change should be declared immutable or constant

Avoids a Gsset (20000 gas) in the constructor, and replaces the first access in each transaction (Gcoldsload - 2100 gas) and each access thereafter (Gwarmacces - 100 gas) with a PUSH32 (3 gas).

Instances (12):

Trading.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L121 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L123 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L123

TradingExtension.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L13 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L22 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L23 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L24

Position.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L73 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L74

GovNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L18 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L20

BondNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L28

[G-03] <x> += <y> costs more gas than <x> = <x> + <y> for state variables

Instances (27)

Trading.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L509

TradingExtension.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L185

Position.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L62 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L102 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L109

PairsContract.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/PairsContract.sol#L156 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/PairsContract.sol#L176

GovNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L52 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L54 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L68 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L79 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L96 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L99 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L278 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L290

Lock.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L73

BondNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L68 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L115 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L117 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L119 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L152 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L180 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L183 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L221 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L225 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L333 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L334

[G-04] Not using the named return variables when a function returns, wastes deployment gas

Instances (44):

IBondNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IBondNFT.sol#L12 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IBondNFT.sol#L35

IGovNFT.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IGovNFT.sol#L6 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IGovNFT.sol#L7 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IGovNFT.sol#L8

ILayerZeroEndpoint.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroEndpoint.sol#L15 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroEndpoint.sol#L24 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroEndpoint.sol#L50

ILayerZeroReceiver.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroReceiver.sol#L11

ILayerZeroUserApplicationConfig.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroUserApplicationConfig.sol#L11 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroUserApplicationConfig.sol#L15 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroUserApplicationConfig.sol#L19 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroUserApplicationConfig.sol#L24

IPairsContract.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPairsContract.sol#L25 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPairsContract.sol#L26 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPairsContract.sol#L27

IPosition.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L36 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L37 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L38 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L39 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L40 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L41 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L42 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L47 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L48 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L49 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L50 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L51 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L52 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L53

IReferrals.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IReferrals.sol#L7 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IReferrals.sol#L8

IStableVault.sol https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IStableVault.sol#L6

ITrading.so https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L30 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L38 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L48 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L57 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L67 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L78 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L86 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L91 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L100 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L106 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L112

[G-05] Use a more recent version of solidity

Use a solidity version of at least 0.8.0 to get overflow protection without SafeMath. Use a solidity version of at least 0.8.2 to get compiler automatic inlining. Use a solidity version of at least 0.8.3 to get better struct packing and cheaper multiple storage reads. Use a solidity version of at least 0.8.4 to get custom errors, which are cheaper at deployment than revert()/require() strings. Use a solidity version of at least 0.8.10 to have external calls skip contract existence checks if the external call has a return value. Use a solidity version of at least 0.8.12 to get string.concat() instead of abi.encodePacked(<str>,<str>). Use a solidity version of at least 0.8.13 to get the ability to use using for with a list of free functions.

Instances (22):

https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/TradingExtension.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Position.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/PairsContract.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Referrals.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/StableToken.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/StableVault.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L2

https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/utils/MetaContext.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IBondNFT.sol#L2 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IGovNFT.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroEndpoint.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroReceiver.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ILayerZeroUserApplicationConfig.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPairsContract.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IPosition.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IReferrals.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/IStableVault.sol#L3 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/interfaces/ITrading.sol#L5

https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/utils/TradingLibrary.sol#L2