Gas Optimizations

[code423n4]

State variables only set in the constructor should be declared immutable

Avoids a Gsset (20000 gas)

1. File: contracts/ManagedIndex.sol (line 17)

   bytes32 private REWEIGHT_INDEX_ROLE;

2. File: contracts/PhuturePriceOracle.sol (line 24)

   address public base;

3. File: contracts/PhuturePriceOracle.sol (line 27)

   address public registry;

4. File: contracts/PhuturePriceOracle.sol (line 33)

   uint8 private baseDecimals;

State variables can be packed into fewer storage slots

If variables occupying the same slot are both written the same function or by the constructor, avoids a separate Gsset (20000 gas). Reads of the variables are also cheaper

1. File: contracts/PhuturePriceOracle.sol (line 24)

   address public base;

   Variable ordering with 3 slots instead of the current 4: mapping(32):priceOracleOf, address(20):base, uint8(1):baseDecimals, address(20):registry

State variables should be cached in stack variables rather than re-reading them from storage

The instances below point to the second access of a state variable within a function. Caching will replace each Gwarmaccess (100 gas) with a much cheaper stack read. Less obvious optimizations include having local storage variables of mappings within state variable mappings or mappings within state variable structs, having local storage variables of structs within mappings, or having local caches of state variable contracts/addresses.

1. File: contracts/PhuturePriceOracle.sol (line 84)

       return IPriceOracle(priceOracleOf[_asset]).refreshedAssetPerBaseInUQ(_asset);

2. File: contracts/PhuturePriceOracle.sol (line 94)

       return IPriceOracle(priceOracleOf[_asset]).lastAssetPerBaseInUQ(_asset);

3. File: contracts/UniswapV2PathPriceOracle.sol (line 35) (save asset pointer for next iteration of the loop)

           address asset = path[i + 1];

4. File: contracts/UniswapV2PathPriceOracle.sol (line 50) (save asset pointer for next iteration of the loop)

           address asset = path[i + 1];

5. File: contracts/UniswapV2PriceOracle.sol (line 51)

       uint32 timeElapsed = blockTimestamp - blockTimestampLast;

6. File: contracts/vToken.sol (line 219)

       IERC20(asset).safeTransfer(_recipient, Math.min(_amount, balance));

Result of static calls should be cached in stack variables rather than re-calling storage-touching functions

Caching will replace each Gwarmaccess (100 gas) with a much cheaper stack read.

1. File: contracts/IndexLogic.sol (line 41)

           if (weightOf[assets.at(i)] == 0) {

2. File: contracts/ManagedIndexReweightingLogic.sol (line 40)

           uint availableAssets = IvToken(IvTokenFactory(vTokenFactory).createOrReturnVTokenOf(assets.at(i)))

3. File: contracts/TopNMarketCapReweightingLogic.sol (line 39)

           uint availableAssets = IvToken(IvTokenFactory(vTokenFactory).createOrReturnVTokenOf(assets.at(i)))

x = x + y is cheaper than x += y

1. File: contracts/libraries/NAV.sol (line 28)

       self.balanceOf[_from] -= _amount;

2. File: contracts/libraries/NAV.sol (line 29)

       self.balanceOf[_to] += _amount;

<array>.length should not be looked up in every loop of a for-loop

Even memory arrays incur the overhead of bit tests and bit shifts to calculate the array length. Storage array length checks incur an extra Gwarmaccess (100 gas) PER-LOOP.

1. File: contracts/BaseIndex.sol (line 78)

       for (uint i; i < _assets.length; ++i) {

2. File: contracts/ManagedIndexReweightingLogic.sol (line 50)

       for (uint i; i < _updatedAssets.length; ++i) {

3. File: contracts/ManagedIndexReweightingLogic.sol (line 96)

       for (uint i; i < _inactiveAssets.length; ++i) {

4. File: contracts/ManagedIndex.sol (line 30)

       for (uint i; i < _assets.length; ++i) {

5. File: contracts/TopNMarketCapIndex.sol (line 48)

       for (uint i; i < _assets.length; ++i) {

6. File: contracts/TopNMarketCapReweightingLogic.sol (line 104)

       for (uint i; i < _inactiveAssets.length; ++i) {

7. File: contracts/TrackedIndex.sol (line 35)

       for (uint i; i < _assets.length; ++i) {

++i/i++ should be unchecked{++i}/unchecked{++i} when it is not possible for them to overflow, as is the case when used in for- and while-loops

1. File: contracts/BaseIndex.sol (line 78)

       for (uint i; i < _assets.length; ++i) {

2. File: contracts/IndexLogic.sol (line 39)

       for (uint i; i < assets.length(); ++i) {

3. File: contracts/IndexLogic.sol (line 60)

       for (uint i; i < inactiveAssets.length(); ++i) {

4. File: contracts/IndexLogic.sol (line 102)

       for (uint i; i < length; ++i) {

5. File: contracts/IndexLogic.sol (line 125)

       for (uint i; i < length + inactiveAssets.length(); ++i) {

6. File: contracts/ManagedIndexReweightingLogic.sol (line 38)

       for (uint i; i < assets.length(); ++i) {

7. File: contracts/ManagedIndexReweightingLogic.sol (line 50)

       for (uint i; i < _updatedAssets.length; ++i) {

8. File: contracts/ManagedIndexReweightingLogic.sol (line 96)

       for (uint i; i < _inactiveAssets.length; ++i) {

9. File: contracts/ManagedIndex.sol (line 30)

       for (uint i; i < _assets.length; ++i) {

10. File: contracts/TopNMarketCapIndex.sol (line 48)

        for (uint i; i < _assets.length; ++i) {

11. File: contracts/TopNMarketCapReweightingLogic.sol (line 37)

        for (uint i; i < assets.length(); ++i) {

12. File: contracts/TopNMarketCapReweightingLogic.sol (line 51)

        for (uint _i; _i < diff.assetCount; ++_i) {

13. File: contracts/TopNMarketCapReweightingLogic.sol (line 104)

        for (uint i; i < _inactiveAssets.length; ++i) {

14. File: contracts/TrackedIndexReweightingLogic.sol (line 37)

        for (uint i; i < assets.length(); ++i) {

15. File: contracts/TrackedIndexReweightingLogic.sol (line 66)

        for (uint i; i < assets.length(); ++i) {

16. File: contracts/TrackedIndex.sol (line 35)

        for (uint i; i < _assets.length; ++i) {

17. File: contracts/UniswapV2PathPriceOracle.sol (line 34)

        for (uint i = 0; i < path.length - 1; i++) {

18. File: contracts/UniswapV2PathPriceOracle.sol (line 49)

        for (uint i = 0; i < path.length - 1; i++) {

require()/revert() strings longer than 32 bytes cost extra gas

1. File: contracts/TopNMarketCapIndex.sol (line 74)

               revert("TopNMarketCapIndex: REWEIGH_FAILED");

2. File: contracts/TopNMarketCapReweightingLogic.sol (line 67)

               require(IAccessControl(registry).hasRole(ASSET_ROLE, asset), "TopNMarketCapIndex: INVALID_ASSET");

3. File: contracts/UniswapV2PathPriceOracle.sol (line 25)

       require(_oracles.length == _path.length - 1, "UniswapV2PathPriceOracle: ORACLES");

Not using the named return variables when a function returns, wastes deployment gas

1. File: contracts/vToken.sol (line 91)

       return _mint(msg.sender);

2. File: contracts/vToken.sol (line 96)

       return _burn(_recipient);

Using > 0 costs more gas than != 0 when used on a uint in a require() statement

1. File: contracts/IndexLogic.sol (line 76)

           require(lastAssetBalanceInBase > 0, "Index: INSUFFICIENT_AMOUNT");

2. File: contracts/IndexLogic.sol (line 98)

       require(value > 0, "Index: INSUFFICIENT_AMOUNT");

3. File: contracts/libraries/FullMath.sol (line 35)

               require(denominator > 0);

4. File: contracts/libraries/IndexLibrary.sol (line 29)

       require(_assetPerBaseInUQ > 0, "IndexLibrary: ORACLE");

5. File: contracts/libraries/NAV.sol (line 49)

       require(shares > 0, "NAV: INSUFFICIENT_AMOUNT");

6. File: contracts/libraries/NAV.sol (line 59)

       require(amount > 0, "NAV: INSUFFICIENT_SHARES_BURNED");

It costs more gas to initialize variables to zero than to let the default of zero be applied

1. File: contracts/UniswapV2PathPriceOracle.sol (line 34)

       for (uint i = 0; i < path.length - 1; i++) {

2. File: contracts/UniswapV2PathPriceOracle.sol (line 49)

       for (uint i = 0; i < path.length - 1; i++) {

++i costs less gas than ++i, especially when it's used in for-loops (--i/i-- too)

1. File: contracts/UniswapV2PathPriceOracle.sol (line 34)

       for (uint i = 0; i < path.length - 1; i++) {

2. File: contracts/UniswapV2PathPriceOracle.sol (line 49)

       for (uint i = 0; i < path.length - 1; i++) {

Splitting require() statements that use && saves gas

See this issue for an example

1. File: contracts/ChainlinkPriceOracle.sol (line 51)

       require(_baseAggregator != address(0) && _base != address(0), "ChainlinkPriceOracle: ZERO");

2. File: contracts/ChainlinkPriceOracle.sol (line 86)

       require(basePrice > 0 && quotePrice > 0, "ChainlinkPriceOracle: NEGATIVE");

3. File: contracts/ManagedIndexReweightingLogic.sol (lines 29-34)

       require(
           _updatedAssets.length > 1 &&
               _updatedWeights.length == _updatedAssets.length &&
               _updatedAssets.length <= IIndexRegistry(registry).maxComponents(),
           "ManagedIndex: INVALID"
       );

4. File: contracts/UniswapV2PriceOracle.sol (line 46)

       require(reserve0 != 0 && reserve1 != 0, "UniswapV2PriceOracle: RESERVES");

Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead

When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.

https://docs.soliditylang.org/en/v0.8.11/internals/layout_in_storage.html Use a larger size then downcast where needed

1. File: contracts/ChainlinkPriceOracle.sol (line 23)

       uint8 answerDecimals;

2. File: contracts/ChainlinkPriceOracle.sol (line 24)

       uint8 decimals;

3. File: contracts/ChainlinkPriceOracle.sol (line 38)

   uint8 private immutable baseDecimals;

4. File: contracts/ChainlinkPriceOracle.sol (line 41)

   uint8 private immutable baseAnswerDecimals;

5. File: contracts/interfaces/IAnatomyUpdater.sol (line 8)

   event UpdateAnatomy(address asset, uint8 weight);

6. File: contracts/interfaces/IFeePool.sol (line 10)

   function mintingFeeInBPOf(address _index) external view returns (uint16);

7. File: contracts/interfaces/IFeePool.sol (line 14)

   function burningFeeInBPOf(address _index) external view returns (uint16);

8. File: contracts/interfaces/IPhuturePriceOracle.sol (line 23)

   function convertToIndex(uint _baseAmount, uint8 _indexDecimals) external view returns (uint);

9. File: contracts/libraries/BP.sol (line 10)

   uint16 constant DECIMAL_FACTOR = 10_000;

10. File: contracts/libraries/FixedPoint112.sol (line 8)

    uint8 internal constant RESOLUTION = 112;

11. File: contracts/libraries/IndexLibrary.sol (line 17)

    uint8 constant MAX_WEIGHT = type(uint8).max;

12. File: contracts/libraries/IndexLibrary.sol (line 26)

        uint8 _weight,

13. File: contracts/ManagedIndexReweightingLogic.sol (line 54)

            uint8 newWeight = _updatedWeights[i];

14. File: contracts/ManagedIndexReweightingLogic.sol (line 66)

                uint8 prevWeight = weightOf[asset];

15. File: contracts/ManagedIndex.sol (line 32)

            uint8 weight = _weights[i];

16. File: contracts/PhuturePriceOracle.sol (line 33)

    uint8 private baseDecimals;

17. File: contracts/PhuturePriceOracle.sol (line 68)

    function convertToIndex(uint _baseAmount, uint8 _indexDecimals) external view override returns (uint) {

18. File: contracts/TopNMarketCapIndex.sol (line 21)

    uint8 public topN;

19. File: contracts/TopNMarketCapIndex.sol (line 38)

        uint8 _topN,

20. File: contracts/TopNMarketCapIndex.sol (line 47)

        uint8 _totalWeight;

21. File: contracts/TopNMarketCapIndex.sol (line 51)

            uint8 weight = _i == 0

22. File: contracts/TopNMarketCapReweightingLogic.sol (line 50)

        uint8 _totalWeight;

23. File: contracts/TopNMarketCapReweightingLogic.sol (line 69)

                    uint8 weight;

24. File: contracts/TrackedIndexReweightingLogic.sol (line 34)

        uint8 totalWeight;

25. File: contracts/TrackedIndexReweightingLogic.sol (line 45)

            uint8 weight = uint8((_capitalizations[i] * type(uint8).max) / _totalCapitalization);

26. File: contracts/TrackedIndex.sol (line 32)

        uint8 totalWeight;

27. File: contracts/TrackedIndex.sol (line 37)

            uint8 weight = uint8((_capitalizations[i] * type(uint8).max) / _totalCapitalization);

28. File: contracts/UniswapV2PriceOracle.sol (line 29)

    uint32 private blockTimestampLast;

29. File: contracts/UniswapV2PriceOracle.sol (line 43)

        uint112 reserve0;

30. File: contracts/UniswapV2PriceOracle.sol (line 44)

        uint112 reserve1;

31. File: contracts/UniswapV2PriceOracle.sol (line 50)

        (uint price0Cml, uint price1Cml, uint32 blockTimestamp) = address(_pair).currentCumulativePrices();

32. File: contracts/UniswapV2PriceOracle.sol (line 51)

        uint32 timeElapsed = blockTimestamp - blockTimestampLast;

33. File: contracts/UniswapV2PriceOracle.sol (line 62)

        (uint price0Cumulative, uint price1Cumulative, uint32 blockTimestamp) = address(pair).currentCumulativePrices();

34. File: contracts/UniswapV2PriceOracle.sol (line 63)

        uint32 timeElapsed = blockTimestamp - blockTimestampLast;

Expressions for constant values such as a call to keccak256(), should use immutable rather than constant

See this issue for a detail description of the issue

1. File: contracts/BaseIndex.sol (line 25)

   bytes32 internal constant INDEX_MANAGER_ROLE = keccak256("INDEX_MANAGER_ROLE");

2. File: contracts/ChainlinkPriceOracle.sol (line 29)

   bytes32 private constant ASSET_MANAGER_ROLE = keccak256("ASSET_MANAGER_ROLE");

3. File: contracts/IndexLogic.sol (line 25)

   bytes32 internal constant ASSET_ROLE = keccak256("ASSET_ROLE");

4. File: contracts/IndexLogic.sol (line 27)

   bytes32 internal constant SKIPPED_ASSET_ROLE = keccak256("SKIPPED_ASSET_ROLE");

5. File: contracts/ManagedIndexReweightingLogic.sol (line 25)

   bytes32 internal constant ASSET_ROLE = keccak256("ASSET_ROLE");

6. File: contracts/PhuturePriceOracle.sol (line 21)

   bytes32 private constant ASSET_MANAGER_ROLE = keccak256("ASSET_MANAGER_ROLE");

7. File: contracts/TopNMarketCapIndex.sol (line 18)

   bytes32 internal constant ORDERER_ROLE = keccak256("ORDERER_ROLE");

8. File: contracts/TopNMarketCapReweightingLogic.sol (line 27)

   bytes32 internal constant ASSET_ROLE = keccak256("ASSET_ROLE");

9. File: contracts/TrackedIndexReweightingLogic.sol (line 25)

   bytes32 internal constant ASSET_ROLE = keccak256("ASSET_ROLE");

10. File: contracts/TrackedIndex.sol (line 17)

    bytes32 internal constant ORDERER_ROLE = keccak256("ORDERER_ROLE");

11. File: contracts/vToken.sol (line 27)

    bytes32 private constant INDEX_ROLE = keccak256("INDEX_ROLE");

12. File: contracts/vToken.sol (line 29)

    bytes32 private constant ORACLE_ROLE = keccak256("ORACLE_ROLE");

13. File: contracts/vToken.sol (line 31)

    bytes32 private constant ORDERER_ROLE = keccak256("ORDERER_ROLE");

14. File: contracts/vToken.sol (line 33)

    bytes32 private constant RESERVE_MANAGER_ROLE = keccak256("RESERVE_MANAGER_ROLE");

Duplicated require()/revert() checks should be refactored to a modifier or function

1. File: contracts/PhuturePriceOracle.sol (line 83)

       require(priceOracleOf[_asset] != address(0), "PhuturePriceOracle: UNSET");

require() or revert() statements that check input arguments should be at the top of the function

Checks that involve constants should come before checks that involve state variables

1. File: contracts/ChainlinkPriceOracle.sol (line 62)

       require(_asset != address(0), "ChainlinkPriceOracle: ZERO");

2. File: contracts/PhuturePriceOracle.sol (line 47)

       require(_base != address(0), "PhuturePriceOracle: ZERO");

3. File: contracts/vToken.sol (line 60)

       require(_asset != address(0), "vToken: ZERO");

Use custom errors rather than revert()/require() strings to save deployment gas

1. File: contracts/BaseIndex.sol (Various lines throughout the file)
2. File: contracts/ChainlinkPriceOracle.sol (Various lines throughout the file)
3. File: contracts/IndexLogic.sol (Various lines throughout the file)
4. File: contracts/libraries/FullMath.sol (Various lines throughout the file)
5. File: contracts/libraries/IndexLibrary.sol (Various lines throughout the file)
6. File: contracts/libraries/NAV.sol (Various lines throughout the file)
7. File: contracts/ManagedIndexReweightingLogic.sol (Various lines throughout the file)
8. File: contracts/ManagedIndex.sol (Various lines throughout the file)
9. File: contracts/PhuturePriceOracle.sol (Various lines throughout the file)
10. File: contracts/TopNMarketCapIndex.sol (Various lines throughout the file)
11. File: contracts/TopNMarketCapReweightingLogic.sol (Various lines throughout the file)
12. File: contracts/TrackedIndexReweightingLogic.sol (Various lines throughout the file)
13. File: contracts/TrackedIndex.sol (Various lines throughout the file)
14. File: contracts/UniswapV2PathPriceOracle.sol (Various lines throughout the file)
15. File: contracts/UniswapV2PriceOracle.sol (Various lines throughout the file)
16. File: contracts/vToken.sol (Various lines throughout the file)

Functions guaranteed to revert when called by normal users can be marked payable

If a function modifier such as onlyOwner is used, the function will revert if a normal user tries to pay the function. Marking the function as payable will lower the gas cost for legitimate callers because the compiler will not include checks for whether a payment was provided.

1. File: contracts/PhuturePriceOracle.sol (line 55)

   function setOracleOf(address _asset, address _oracle) external override onlyRole(ASSET_MANAGER_ROLE) {

2. File: contracts/PhuturePriceOracle.sol (line 62)

   function removeOracleOf(address _asset) external override onlyRole(ASSET_MANAGER_ROLE) {

3. File: contracts/TopNMarketCapIndex.sol (line 68)

   function reweight() external override onlyRole(ORDERER_ROLE) {

4. File: contracts/TrackedIndex.sol (line 57)

   function reweight() external override onlyRole(ORDERER_ROLE) {

5. File: contracts/vToken.sol (lines 81-85)

   function transferFrom(
       address _from,
       address _to,
       uint _shares
   ) external override nonReentrant onlyRole(ORDERER_ROLE) {

6. File: contracts/vToken.sol (line 90)

   function mint() external override nonReentrant onlyRole(INDEX_ROLE) returns (uint shares) {

7. File: contracts/vToken.sol (line 95)

   function burn(address _recipient) external override nonReentrant onlyRole(INDEX_ROLE) returns (uint amount) {

8. File: contracts/vToken.sol (line 100)

   function mintFor(address _recipient) external override nonReentrant onlyRole(ORDERER_ROLE) returns (uint) {

9. File: contracts/vToken.sol (line 105)

   function burnFor(address _recipient) external override nonReentrant onlyRole(ORDERER_ROLE) returns (uint) {

Use a more recent version of solidity

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

1. File: contracts/BaseIndex.sol (line 3)

   pragma solidity >=0.8.7;

2. File: contracts/ChainlinkPriceOracle.sol (line 3)

   pragma solidity >=0.8.7;

3. File: contracts/IndexLayout.sol (line 3)

   pragma solidity >=0.8.7;

4. File: contracts/IndexLogic.sol (line 3)

   pragma solidity >=0.8.7;

5. File: contracts/interfaces/external/IChainLinkFeed.sol (line 3)

   pragma solidity >=0.8.7;

6. File: contracts/interfaces/external/IWETH.sol (line 3)

   pragma solidity >=0.8.7;

7. File: contracts/interfaces/IAnatomyUpdater.sol (line 3)

   pragma solidity >=0.8.7;

8. File: contracts/interfaces/IChainlinkPriceOracle.sol (line 3)

   pragma solidity >=0.8.7;

9. File: contracts/interfaces/IFeePool.sol (line 3)

   pragma solidity >=0.8.7;

10. File: contracts/interfaces/IIndexFactory.sol (line 3)

    pragma solidity >=0.8.7;

11. File: contracts/interfaces/IIndexLayout.sol (line 3)

    pragma solidity >=0.8.7;

12. File: contracts/interfaces/IIndexLogic.sol (line 3)

    pragma solidity >=0.8.7;

13. File: contracts/interfaces/IIndexRegistry.sol (line 3)

    pragma solidity >=0.8.7;

14. File: contracts/interfaces/IIndex.sol (line 3)

    pragma solidity >=0.8.7;

15. File: contracts/interfaces/IManagedIndexReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

16. File: contracts/interfaces/IManagedIndex.sol (line 3)

    pragma solidity >=0.8.7;

17. File: contracts/interfaces/INameRegistry.sol (line 3)

    pragma solidity >=0.8.7;

18. File: contracts/interfaces/IOrderer.sol (line 3)

    pragma solidity >=0.8.7;

19. File: contracts/interfaces/IPhuturePriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

20. File: contracts/interfaces/IPriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

21. File: contracts/interfaces/IReweightableIndex.sol (line 3)

    pragma solidity >=0.8.7;

22. File: contracts/interfaces/ITopNMarketCapCategories.sol (line 3)

    pragma solidity >=0.8.7;

23. File: contracts/interfaces/ITopNMarketCapIndexFactory.sol (line 3)

    pragma solidity >=0.8.7;

24. File: contracts/interfaces/ITopNMarketCapIndexReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

25. File: contracts/interfaces/ITrackedIndexReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

26. File: contracts/interfaces/IUniswapV2PathPriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

27. File: contracts/interfaces/IUniswapV2PriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

28. File: contracts/interfaces/IvTokenFactory.sol (line 3)

    pragma solidity >=0.8.7;

29. File: contracts/interfaces/IvToken.sol (line 3)

    pragma solidity >=0.8.7;

30. File: contracts/libraries/AUMCalculationLibrary.sol (line 3)

    pragma solidity >=0.8.7;

31. File: contracts/libraries/BP.sol (line 3)

    pragma solidity >=0.8.7;

32. File: contracts/libraries/FixedPoint112.sol (line 3)

    pragma solidity >=0.8.7;

33. File: contracts/libraries/IndexLibrary.sol (line 3)

    pragma solidity >=0.8.7;

34. File: contracts/libraries/NAV.sol (line 3)

    pragma solidity >=0.8.7;

35. File: contracts/ManagedIndexReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

36. File: contracts/ManagedIndex.sol (line 3)

    pragma solidity >=0.8.7;

37. File: contracts/PhutureIndex.sol (line 3)

    pragma solidity >=0.8.7;

38. File: contracts/PhuturePriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

39. File: contracts/TopNMarketCapIndex.sol (line 3)

    pragma solidity >=0.8.7;

40. File: contracts/TopNMarketCapReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

41. File: contracts/TrackedIndexReweightingLogic.sol (line 3)

    pragma solidity >=0.8.7;

42. File: contracts/TrackedIndex.sol (line 3)

    pragma solidity >=0.8.7;

43. File: contracts/UniswapV2PathPriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

44. File: contracts/UniswapV2PriceOracle.sol (line 3)

    pragma solidity >=0.8.7;

45. File: contracts/vToken.sol (line 3)

    pragma solidity >=0.8.7;

[jn-lp]

More than half of the issues were very helpful, thanks!

[moose-code]

Very comprehensive, lots of good things here