Please don't forget the space in `if (`. Also, please write this function as follows to avoid the extra indentation as well as moving `f` to after the condition:
```c++
void Box2DWorld::SayGoodbye(b2Fixture *fixture)
{
    if (!mEnableContactEvents)
        return;

    Box2DFixture *f = toBox2DFixture(fixture);

    QList<ContactEvent> events = mContactListener->events();
    for (int i = events.count() - 1; i >= 0; i--) {
        if (events.at(i).fixtureA == f || events.at(i).fixtureB == f)
            mContactListener->removeEvent(i);
    }
}
```