// When a huge deposit is made, the casting of _value in createLock can allow delegated to overflow into negative a value...
if (_oldLocked.end > block.timestamp && _oldLocked.delegated > 0) {
    // ...these can become negative as a result
    userOldPoint.slope = _oldLocked.delegated / int128(int256(LOCKTIME));
    userOldPoint.bias = userOldPoint.slope * int128(int256(_oldLocked.end - block.timestamp));
}
if (_newLocked.end > block.timestamp && _newLocked.delegated > 0) {
    // ...these can become negative as a result
    userNewPoint.slope = _newLocked.delegated / int128(int256(LOCKTIME));
    userNewPoint.bias = userNewPoint.slope * int128(int256(_newLocked.end - block.timestamp));
}
