[RTU-01C] Improper Evaluation of Assert

[dkuppitz]

RTU-01C: Improper Evaluation of Assert

Type	Severity	Location
Code Style		RebaseTokenUpgradeable.sol:L244

Description:

The RebaseTokenUpgradeable::_checkRebaseOverflow function will evaluate an assert statement that can never evaluate to false.

Example:

function _checkRebaseOverflow(uint256 shares, uint256 index) private view {
    // The condition inside `assert()` can never evaluate `false`, but `toTokens()` would throw an arithmetic
    // exception in case we overflow, and that's all we need.
    assert(shares.toTokens(index) + ERC20Upgradeable.totalSupply() <= type(uint256).max);
}

Recommendation:

While this is detailed in the assert statement's comments, we still advise the code to be wrapped in an unchecked code block and to instead ensure that the addition between shares.toTokens(index) and ERC20Upgradeable::totalSupply does not overflow thus ensuring that no code is unreachable.

[dkuppitz]

Resolved in 94a1ba8.