TokenMigrator Code Style Findings

TMR-01C: First-Time Assignment Optimization

Type	Severity	Location
Gas Optimization		TokenMigrator.sol:L149-L150

Description:

The linked statements increment the burnAmount and mintAmount variables, however, it is known that in the first if clause they will always be zero thus permitting a direct assignment to be made instead.

Example:

Copy
145uint256 burnAmount;
146uint256 mintAmount;
147
148if (wxAmount != 0) {
149    burnAmount += wxBtrfly.xBTRFLYValue(wxAmount);
150    mintAmount += _migrateWxBtrfly(wxAmount);
151}

Recommendation:

We advise this to be done so optimizing the gas cost of those statements.

Alleviation:

Both assignment operations were adjusted to simple assignments optimizing the codebase.

TMR-02C: wxBTRFLY Integration Optimization

Type	Severity	Location
Gas Optimization		TokenMigrator.sol:L91, L149-L150

Description:

The unwrapToBTRFLY function of wxBTRFLY yields the amount of BTRFLY that was ultimately unwrapped. In the TokenMigrator contract, this is measured in a separate call to xBTRFLYValue which is inefficient.

Example:

Copy
85function _migrateWxBtrfly(uint256 amount)
86    internal
87    returns (uint256 mintAmount)
88{
89    // Unwrap wxBTRFLY
90    wxBtrfly.transferFrom(msg.sender, address(this), amount);
91    wxBtrfly.unwrapToBTRFLY(amount);
92
93    return amount;
94}

Recommendation:

We advise the _migrateWxBtrfly function to yield the burnAmount instead and be assigned to it whilst the mintAmount is directly assigned to the wxAmount, optimizing the code's execution cost.

Alleviation:

The codebase was adjusted as advised optimizing the execution cost of the wxBTRFLY conversion path.