Question

I am trying to find memory leak with Visual Leak Detector.
It shows me m_neighbors.push_back(ent); causes leak.

(brief callstack = NeighborCalculatorDummy -> foreach -> list -> allocate)

I use it as NeighborCalculatorDummy<Entity *>, so pushback should just insert pointer in list without any allocation.
All pointers to entities which come through addEntity are deleted elsewhere in code…

How is it possible for push_back to cause a leak?

template <typename entity_type>
class NeighborCalculatorDummy
{
public:
    inline void addEntity(const entity_type & entity)
    {
        m_entities.push_back(entity);
    }

    void calculateNeighbors(const vector_type & position, flt32 radius)
    {
        flt32 rSq = radius*radius;
        m_neighbors.clear();

        std::for_each(m_entities.begin(), m_entities.end(), [&](entity_type ent){
            if(lengthSq(ent->getPosition() - position) <= rSq)
                m_neighbors.push_back(ent);
        });
    }

private:
    std::vector<entity_type> m_entities;
    std::list<entity_type> m_neighbors;
};

edit

here is the code around NeighborCalculator

//#1 
std::list<Vehicle *> vehicles;
vehicles.push_back(new Vehicle);
vehicles.push_back(new Vehicle);
vehicles.push_back(new Vehicle);

//#2 
NeighborCalculatorDummy<Vehicle *> neighborCalculator = new NeighborCalculatorDummy<Vehicle *>();

std::for_each(vehicles.begin(), vehicles.end(), [&](Vehicle * vehicle){
    neighborCalculator->addEntity(vehicle);
});

//#3 impl of addEntity
template <typename entity_type>
void NeighborCalculatorDummy<entity_type>::addEntity(const entity_type & entity)
{
    ...
    m_entities.push_back(entity);  //m_entities is - std::vector<Vehicle *> 
}

//#4 end of program
delete neighborCalculator;

std::for_each(vehicles.begin(), vehicles.end(), [&](Vehicle * vehicle){
    delete vehicle;
});

Answer 1

I have omitted virtual destructor in Entity’s parent. That is why pushbacking it caused a leak.