Compilation error when using C++ template functions that accept as arguments another functions that accept references to pointers

Question

Here is the most basic example of the C++ code that raises this compilation error:

template <typename T>
void TestF(int(*func)(const T&)) {

}

int IntNormal(const int& x) {
    return x;
}

int IntPointer(const int*& x) {
    return *x;
}

int main() {
    TestF<int>(IntNormal); //Works just fine
    TestF<int*>(IntPointer); //Gives compilation error
    return 0;
};

The error Intellisense gives me is :

Error (active)  E0304   no instance of function template "TestF" matches the argument list

Error   C2664   'void TestF<const int*>(int (__cdecl *)(const T &))': cannot convert argument 1 from 'int (__cdecl *)(const int *&)' to 'int (__cdecl *)(const T &)'
        with
        [
            T=const int *
        ]

I just don't understand why it works just fine with normal int but it doesn't with int*, even though it looks as if I was using correct method signature.

Answer 1

At first I wanted to thank Drew Dormann for his link: What is the difference between const int*, const int * const, and int * const?

I have read this and managed to write working code:

template <typename T>
void TestF(int(*func)(const T&)) {

}


int IntNormal(const int& x) {
    return x;
}

int IntPointer(int*const& x) {  //Here is fix - I write int * const & instead of const int * &
    return *x;
}

int main() {
    TestF<int>(IntNormal); //Works just fine
    TestF<int*>(IntPointer);  //Now works after above fix
    return 0;
};