ERC20Rewards.sol: Consider making rewardsToken immutable

Handle hickuphh3 Vulnerability details Impact While it might seem like a good feature to have, being able to switch reward tokens will only be useful for tokens which are equivalent in value probably stablecoins, pegged tokens since it carries over unclaimed rewards from the previous reward...

ERC20Rewards returns wrong rewards if no tokens initially exist

Handle cmichel Vulnerability details The ERC20Rewards.updateRewardsPerToken function exits without updating rewardsPerToken.lastUpdated if totalSupply is zero, i.e., if there are no tokens initially. This leads to an error if there is an active rewards period but not tokens have been minted yet...

ERC20Rewards breaks when setting a different token

Handle cmichel Vulnerability details The setRewards function allows setting a different token. Holders of a previous reward period cannot all be paid out and will receive their old reward amount in the new token. This leads to issues when the new token is more less valuable, or uses different...