#include <iostream>
#include <iomanip>
#include <type_traits>

using namespace std;

class Policy1 {
};

class Policy2 {
};

/********** General settings *********/
template<typename Policy>
struct PolicyTraits {
  static const bool somePolicyProperty = false;

  static const bool anotherPolicyProperty = true;
};

/****** Overriding settings for Policy1       ****************/
template<>
struct PolicyTraits<Policy1> {
  static const bool somePolicyProperty = false;

  static const bool anotherPolicyProperty = false;
};

class SomeClass {
public:

  // Some general template
  template<typename Policy, typename ValueType>
  void SomeFunction(Policy policy, ValueType value) {
    cout << "General template: " << value << endl;
  }

  // The specialization is not avaliable for Policy1
  template<typename Policy>
  void SomeFunction(Policy policy, int value, typename enable_if<PolicyTraits<Policy>::anotherPolicyProperty>::type* = 0) {
    cout << "Some function: integer " << value << endl;
  }
};

int main() {
  cout << boolalpha;
  cout << PolicyTraits<Policy1>::anotherPolicyProperty << endl;  // false
  cout << PolicyTraits<Policy2>::anotherPolicyProperty << endl;  // true

  SomeClass someClass;

  someClass.SomeFunction(Policy2(), "policy 2");  // correct: General template
  someClass.SomeFunction(Policy2(), 123);  // correct: Specialization

  someClass.SomeFunction(Policy1(), "policy 1");  // correct: General template
  someClass.SomeFunction(Policy1(), 456);  // correct: General template
  return 0;
}