MerkleDistributor Code Style Findings

MDR-01C: Potential Error Practicality Enhancement

Type	Severity	Location
Language Specific		MerkleDistributor.sol:L9, L48

Description:

The InvalidProof error is meant to be yielded whenever a Merkle proof verification fails, however, it does not yield the merkleRoot which the verification failed for.

Example:

Copy
39function claim(uint256 index, address account, uint256 amount, bytes32[] calldata merkleProof)
40    public
41    virtual
42    override
43{
44    if (isClaimed(index)) revert AlreadyClaimed();
45
46    // Verify the merkle proof.
47    bytes32 node = keccak256(abi.encodePacked(index, account, amount));
48    if (!MerkleProof.verify(merkleProof, merkleRoot, node)) revert InvalidProof();
49
50    // Mark it claimed and send the token.
51    _setClaimed(index);
52    IERC20(token).safeTransfer(account, amount);
53
54    emit Claimed(index, account, amount);
55}

Recommendation:

We advise a bytes32 argument to be added to the InvalidProof error which signals the merkleRoot the proof failed for, enhancing its off-chain usability.

Alleviation:

The InvalidProof error was expanded to contain a bytes32 variable representing the merkleRoot the validation failed for as per our recommendation.

MDR-02C: Repetitive Value Literal

Type	Severity	Location
Code Style		MerkleDistributor.sol:L26, L27, L34, L35

Description:

The linked value literal is repeated across the codebase multiple times.

Example:

Copy
26uint256 claimedWordIndex = index / 256;

Recommendation:

We advise it to be set to a constant variable instead optimizing the legibility of the codebase.

Alleviation:

The 256 value literal was relocated to an aptly named WORD_SIZE contract-level constant variable, increasing the legibility of the codebase.