Unnecessary checked arithmetic in for loops

[code423n4]

Handle

WatchPug

Vulnerability details

There is no risk of overflow caused by increamenting the iteration index in for loops (the i++ in for for (uint256 i = 0; i < idsIn.length; i++)).

Increments perform overflow checks that are not necessary in this case.

Recommendation

Surround the increment expressions with an unchecked { ... } block to avoid the default overflow checks. For example, change the for loop:

https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXMarketplaceZap.sol#L437-L440

    for (uint256 i = 0; i < idsIn.length; i++) {
      transferFromERC721(assetAddress, idsIn[i], vault);
      approveERC721(assetAddress, vault, idsIn[i]);
    }

to:

    for (uint256 i = 0; i < idsIn.length;) {
      transferFromERC721(assetAddress, idsIn[i], vault);
      approveERC721(assetAddress, vault, idsIn[i]);

      unchecked { ++i; }
    }

[dmvt]

duplicate of #198