Why do I get a c26486 warning when passing a shared ptr object

Question

I have written some test code to use with the c++ guidelines code checker in vs2019. I get the following warnings and I am not sure how to get rid of them.

Line 60 - warning C26486: Don't pass a pointer that may be invalid to a function. Parameter 0 '@@v' in call to 'icall' may be invalid (lifetime.3).

line 79 warning C26486: Don't pass a pointer that may be invalid to a function. Parameter 0 '@a' in call to 'icall' may be invalid (lifetime.3).

#include <memory>
#include <string>
#include <iostream>
#include <vector>

using namespace::std;
class IReconQElem {

public:
    virtual string getDesc() = 0;
};
class classA : public IReconQElem {

public:
    int a;
    int b;
    string desc;
    string getDesc() override {
        return desc;
    }

    classA(int a) noexcept {
        this->a = a;
        b = 0;
    }
    virtual ~classA() {

    }

};

static void g(string a) {
    cout << a;
}

typedef shared_ptr<IReconQElem> IReconQElemPtr;
typedef vector<IReconQElemPtr>  IReconQElemPtrsV;
IReconQElemPtrsV v;

static IReconQElemPtr func(IReconQElemPtr tid)
{

    v.push_back(tid);
    IReconQElemPtr ptr;
    for (auto& elem1 : v) {
        g(elem1->getDesc()); //this generates the warning
        break;
    }
    return ptr;
}

int main()
{
    IReconQElemPtr tid = make_shared<classA>(1); 
    IReconQElemPtr tid1 = make_shared<classA>(2);
    v.push_back(tid);
    v.push_back(tid1);

    auto a = func(tid);
    auto a1 = func(tid1);
    auto copy = a;
    g(a->getDesc()); //this generates the warning
    return 0;
}

Answer 1

The warning is correct, elem1 in func and a in main could both be a shared_ptr holding a nullptr . You could use gsl::not_null to make clear that the pointer can't be nullptr .