functionStatic flags member callbacks

[Long Huang]

Minimal reproduction:

scratch_functionStatic_callback.h:

#pragma once

class CallbackReceiver
{
public:
   void OnEvent(int)
   {
   }
};

scratch_functionStatic_callback.cpp:

#include "scratch_functionStatic_callback.h"

template<typename Receiver>
void Register(Receiver* receiver, void (Receiver::*callback)(int))
{
   (receiver->*callback)(1);
}

int main()
{
   CallbackReceiver receiver;
   Register(&receiver, &CallbackReceiver::OnEvent);
}

Expected

• Expected: OnEvent remains a non-static member, registration requires a
  void (Receiver::*)(int), while a static method produces a different
  function-pointer type.

Actual

when Cppcheck analyzes the header by itself:

scratch_functionStatic_callback.h:6:9: style: The member function 'CallbackReceiver::OnEvent' can be static. [functionStatic]

[Long Huang]

For the record, these warnings appear when cppcheck only analyzes the header & not the translation unit. So maybe not really a defect but just how it goes...