Multi-model AI security review with cross-examination

A staker who withdraws everything forfeits the rewards accrued since their last checkpoint. The forfeited amount stays in the vault and is paid out to the remaining stakers.

1. withdraw calls _checkpoint only when remaining != 0 (lines 91-93).
2. A full withdrawal sets the balance to 0 at line 94 without settling earned for the period since the last checkpoint.
3. claim reads earned[msg.sender], which was never updated for that period (lines 61-64).

function withdraw(uint256 shares) external nonReentrant {
    if (shares == 0) revert ZeroAmount();
    uint256 remaining = balanceOf[msg.sender] - shares;
    if (remaining != 0) {
        _checkpoint(msg.sender);
    }
    balanceOf[msg.sender] = remaining;
    totalShares -= shares;
    token.safeTransfer(msg.sender, shares);
}

A full exit is meant to go through exit(), which claims first.

Resolvedwithdraw is external and accepts the full balance. Nothing at lines 88-97 sends a full withdrawal to exit().

• No test was run. The forfeited amount follows from lines 61-64 and 91-94.

Call _checkpoint(msg.sender) before the balance changes, with no condition on remaining.

Write the test: stake, accrue, withdraw the full balance, then assert earned equals the accrued amount.