Neo Tokyo contest - 0xSolus's results

---- Bytes.sol ----

Constructor not checking for 0 addresses when deployed in Bytes.sol L80. A mistake on the address is going to affect the whole implementation of the contract and can affect the tokens being minted and burned to 0 address.

UpgradeBytes(_amounts) avoids 0 amount check in Bytes.sol L95, if a user by accident calls the function with 0 as _amount it will actually execute costing gas to the user. The recommendation is to make sure that require(_amount != 0). The following assertion in the tests doesn't revert:

it("should revert on amount 0", async function () {
   await expect(NTBytes2_0.connect(alice.signer).upgradeBytes(0)).to.be.reverted
   })

---- NeoTokyoStaker.sol ----

In L1205 consider omitting the check of the range of enum _assetType as solidity already checks for it and emits a Panic error check. In this case the revert InvalidAssetType(uint256(_assetType)) is never hit.
In any case, the range of enum AssetType is 0..3, so the proper range check will be:

if (uint8(_assetType) > 3) {
  revert InvalidAssetType(uint256(_assetType));
}  

There's a similar occurrence in L1688

---- NeoTokyoStaker.sol ----

Redundant Code because of repetition in the following lines:
L638-L641 L663-L667 Consider moving that logic into a seperate function to save gas.

function getVaultMultiplier(uint256 _vaultId) internal returns(string memory){
  // Retrieve the credit rate multiplier of the Vault.
  IGenericGetter vault = IGenericGetter(VAULT);
  return (_vaultId != 0) ? vault.getCreditMultiplier(_vaultId) : "";
}

Replace L644 return identityCreditYield[rewardRate][getVaultMultiplier(_vaultId)];
Replace L670
return vaultCreditMultiplier[getVaultMultiplier(_vaultId)];

---- NeoTokyoStaker.sol ---- Consider changing _stringEquals(_a, _b) in L824 with 2107 gas cost for:

/**
 * @dev Returns true if the two strings are equal.
 */
function equal(string memory a, string memory b) internal pure returns (bool) {
  return keccak256(bytes(a)) == keccak256(bytes(b));
}

This is implemented by openzeppelin, it's less code, easier to read and more gas efficient with 1931 gas of execution cost vs 2107.