Unused private function false positive but it is used in a "compare" functor

[Roy]

Code :

struct key_compare;
struct key {
  bool top;
  int serial_num;

  friend struct key_compare;

private:
  size_t get_hash() const { return (serial_num >> 1) + (top << 10); }
};

struct key_compare {
  bool operator()(const key &lhs, const key &rhs) const {
    return lhs.get_hash() < rhs.get_hash();
  }
};

struct items {
  int a;
  int b;
  int c;
  std::string g;
}

std::map<key, items, key_compare>
    map_;

int main() {
  map_.insert_or_assign({true, 1}, items());
  map_.insert_or_assign({true, 2}, items());
}

Cpp check output:

foo.cpp:9:10: style: Unused private function: 'key::get_hash' [unusedPrivateFunction]
  size_t get_hash() const { return (serial_num >> 1) + (top << 10); }

cppcheck version : 2.4.1

[Daniel Marjamäki]

Thanks! I can reproduce. I have created ticket https://trac.cppcheck.net/ticket/10265