As4626 Code Style Findings

A62-01C: Inefficient mapping Lookups

Type	Severity	Location
Gas Optimization		As4626.sol:L166, L182

Description:

The linked statements perform key-based lookup operations on mapping declarations from storage multiple times for the same key redundantly.

Example:

Copy
166Erc7540Request storage request = req.byOwner[_owner];
167uint256 claimable = claimableRedeemRequest(_owner);
168last.sharePrice = sharePrice();
169
170uint256 price = (claimable >= _shares)
171    ? AsMaths.min(last.sharePrice, request.sharePrice) // worst of if pre-existing request
172    : last.sharePrice; // current price
173
174// amount/shares cannot be higher than the share price (dictated by the inline convertToAssets below)
175if (_amount > _shares.mulDiv(price * weiPerAsset, weiPerShare ** 2))
176    revert AmountTooHigh(_amount);
177
178if (msg.sender != _owner)
179    _spendAllowance(_owner, msg.sender, _shares);
180
181if (claimable >= _shares) {
182    req.byOwner[_owner].shares -= _shares;
183    req.totalRedemption -= AsMaths.min(_shares, req.totalRedemption); // min 0
184    req.totalClaimableRedemption -= AsMaths.min(
185        _shares,
186        req.totalClaimableRedemption
187    ); // min 0
188} else {

Recommendation:

As the lookups internally perform an expensive keccak256 operation, we advise the lookups to be cached wherever possible to a single local declaration that either holds the value of the mapping in case of primitive types or holds a storage pointer to the struct contained.

Alleviation (59b75fbee1d8f3dee807c928f18be41c58b904e1):

The optimization has been applied per our recommendation, using the request storage pointer that already exists for the shares member mutation in the second highlighted line.

A62-02C: Redundant Duplication of Code

Type	Severity	Location
Code Style		As4626.sol:L146

Description:

The referenced statement will locally perform the statements of the As4626::previewDeposit function redundantly.

Example:

Copy
146shares = _deposit(_amount, convertToShares(_amount, false).subBp(exemptionList[_receiver] ? 0 : fees.entry), _receiver);

Recommendation:

We advise the function to be invoked directly, optimizing the legibility of the code.

Alleviation (59b75fbee1d8f3dee807c928f18be41c58b904e1):

The referenced statements are no longer part of the As4626::safeDeposit function, rendering this exhibit no longer applicable.

A62-03C: Redundant Parenthesis Statements

Type	Severity	Location
Code Style		As4626.sol:L170, L801

Description:

The referenced statements are redundantly wrapped in parenthesis' (()).

Example:

Copy
170uint256 price = (claimable >= _shares)

Recommendation:

We advise them to be safely omitted, increasing the legibility of the codebase.

Alleviation (59b75fbee1d8f3dee807c928f18be41c58b904e1):

The first of the two referenced instances is no longer applicable whilst the second instance has been corrected in its updated form rendering this exhibit fully addressed.

A62-04C: Repetitive Value Literal

Type	Severity	Location
Code Style		As4626.sol:L96, L175, L190, L200

Description:

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

Example:

Copy
96if (_amount > maxDeposit(address(0)) || _shares > _amount.mulDiv(weiPerShare ** 2, last.sharePrice * weiPerAsset))

Recommendation:

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

Alleviation (59b75fbee1d8f3dee807c928f18be41c58b904e1):

All referenced instances of weiPerShare ** 2 have been replaced by a _WEI_PER_SHARE_SQUARED constant per our recommendation, optimizing the code's legibility.