heisenbug!

gistfile1.cpp

// this works!
for (RigidBodyList::const_iterator i = rigid_bodies.begin(), 
	end = rigid_bodies.end(); i != end; ++i) {
	1+1; // do nothing
	checkCollision(target_body, *i);
}

// this does not work.
for (RigidBodyList::const_iterator i = rigid_bodies.begin(), 
	end = rigid_bodies.end(); i != end; ++i) {
	checkCollision(target_body, *i);
}