Why doesn't _writeCheckpoint() in ERC20Vote.sol underflow?

This part in _writeCheckpoint(), if pos, which is the length of the Checkpoint[], equals 0, why doesn't ckpts[pos - 1] cause an underflow? Doesn't == precede &&?

if (pos > 0 && ckpts[pos - 1].fromBlock == block.number) {
            ckpts[pos - 1].votes = SafeCast.toUint224(newWeight);

Edit: it seems that the function will first recognize &&, then if pos>0 is not true, it will not evaluate ckpts[pos - 1], is there a doc about it? As something like https://docs.soliditylang.org/en/v0.8.12/cheatsheet.html#order puts && in the last in precedence, so it may seem that the function will evaluate both two bools first then && at a glance.