Core Contracts

Summary

When looking at AAVE ScaledBalanceTokenBase contract, we can see the following line:

scaledBalance is effectively the amount of interest-bearing token (RToken).

But in our case, scaleBalance is computed as follows:

This is problematic, because the balanceOf function in RToken is meant to return the balance of underlying token, i.e, balance after multiplying the RToken amount by the index :

Impact

The impact is medium as it leads to incorrect computation of scaledBalance. With the current design, there are no consequences because scaledBalance is only used to compute balanceIncrease which is never used.

In AAVE aToken implementation, balanceIncrease is used for event emission, but this part has been forgotten in RAAC protocol.

Tools Used

Manual review.

Recommendations

Make sure to correctly compute scaledBalance using super.balanceOf just like AAVE aTokens implementation.