Given
std::vector<Rule>& topPriorityRules;
The correct way to remove the first element of the referenced vector is
topPriorityRules.erase(topPriorityRules.begin());
which is exactly what you suggested.
Looks like i need to do iterator overloading.
There is no need to overload an iterator in order to erase first element of std::vector.
P.S. Vector (dynamic array) is probably a wrong choice of data structure if you intend to erase from the front.