VTVL contest - carrotsmuggler's results

QA

1. Contract VariableSupplyERC20Token.sol has a variable named maxSupply, which has a different meaning than mintable supply. maxSupply's meaning is closer to mintablesupply + initialsupply, or the ceiling for totalsupply. It is better to rename it to maxMintableSupply or something similar, to make it clear that it is only counting tokens yet to be minted.

Gas

1. VTVLVesting.sol:353: ++i is more efficient than i++

i++ increments i and returns the initial value of i, but ++i returns the actual incremented value skipping the creation of a temporary variable, saving ~5 gas/iteration.

2. VTVLVesting.sol:374,377,381 usrClaim.amountWithdrawn should be cached in memory

require(allowance > usrClaim.amountWithdrawn, "NOTHING_TO_WITHDRAW");
//
uint112 amountRemaining = allowance - usrClaim.amountWithdrawn;
//
usrClaim.amountWithdrawn += amountRemaining;

Multiple use of storage variable costs 100 gas to load from warm state each time. Caching in memory makes future calls cost 3 gas, saving ~97 gas each call. Caching here changes average gas cost from 69082 to 68740 (hardhat gas reporter average)

Use cached value for increment as:

numTokensReservedForVesting = cached + allocatedAmount;

3. VTVLVesting.sol:426,429 usrClaim.amountWithdrawn should be cached in memory

require( _claim.amountWithdrawn < finalVestAmt, "NO_UNVESTED_AMOUNT");
//
uint112 amountRemaining = finalVestAmt - _claim.amountWithdrawn;

Multiple use of storage variable costs 100 gas to load from warm state each time. Caching in memory makes future calls cost 3 gas, saving ~97 gas each call. Caching here changes average gas cost from 36548 to 36451 (hardhat gas reporter average)

4. VTVLVesting.sol:295,301 numTokensReservedForVesting should be cached in memory

require(tokenAddress.balanceOf(address(this)) >= numTokensReservedForVesting + allocatedAmount, "INSUFFICIENT_BALANCE");
//
numTokensReservedForVesting += allocatedAmount; // track the allocated amount

Multiple use of storage variable costs 100 gas to load from warm state each time. Caching in memory makes future calls cost 3 gas, saving ~97 gas each call. Caching here changes average gas cost from 36548 to 36451 (hardhat gas reporter average)

Use cached value for increment as:

numTokensReservedForVesting = cached + allocatedAmount;

5. VTVLVesting.sol:166,167,170 startTimestamp should be cached in memory

if(_referenceTs > _claim.startTimestamp) {
//
uint40 currentVestingDurationSecs = _referenceTs - _claim.startTimestamp; // How long since the start
//
uint40 finalVestingDurationSecs = _claim.endTimestamp - _claim.startTimestamp; // length of the interval

Multiple use of storage variable costs 100 gas to load from warm state each time. Caching in memory makes future calls cost 3 gas, saving ~97 gas each call. Caching here changes average gas cost from 36548 to 36451 (hardhat gas reporter average)