Don't understand why this overflows revert

Question

I have a timelock on an ERC20 contract, from year 0 to 9, it works until year 4, but from year 5 onwards it reverts. It fails both on minting and checking (Using 52 seconds intead of weeks for testing):

constructor() ERC20("Coin", "C") {        
    deploymentTime = block.timestamp;        
} 

function checkMintDate(uint8 year) public view returns (uint256){
    return deploymentTime + 52 seconds * year;
} 

function mint(uint8 year) public onlyOwner {        
    require (year <= 9, "cannot claim for more than 10 years");
    require(block.timestamp >= deploymentTime + 52 seconds * year, "Not that year yet");        
    require(!yearClaimed[year], "you already claimed that year");
    yearClaimed[year] = true;
    _mint(msg.sender, yearlyMintAmount);
} 

When deployed to the testnet, remix gives this data, which is the overflow one:

"code": "3", "message": "execution reverted", "output": "0x4e487b710000000000000000000000000000000000000000000000000000000000000011"

Any ideas?, thanks!

Answer 1

So on the first analyse, you didnt convert correctly in year

function checkMintDate(uint8 year) public view returns (uint256){
return deploymentTime + 52 weeks * year;} 

and for the require the same:

require(block.timestamp >= deploymentTime + 52 weeks * year, "Not that year yet");   

---

For the error : 0x11: If an arithmetic operation results in underflow or overflow outside of an unchecked { ... } block.

So it s a type conversion issue Uint8 max value is 256 but 5*52 is over 260.

To solve the problem: the best practice is to send the parameter in uint256, it's costing less gas and avoid this error.

If not just then cast : ....52 seconds * uint256(year)...

Answer 2

Resolved in another forum, had to change year to uint256:

https://forum.openzeppelin.com/t/dont-understand-this-overflow-in-my-timelock/33075/4