#include <iostream>
#include <functional>
#include <vector>
 
int add(int a, int b) { return a + b; }
 
using bound_add_t = decltype(std::bind(add, std::placeholders::_1, int()));
 
int main() {
  std::vector<bound_add_t> vec;
  int y = 2;
  vec.emplace_back(add,std::placeholders::_1, y); // <- this causes the problem
  vec.emplace_back(add,std::placeholders::_1, 2);
  vec.emplace_back(add,std::placeholders::_1, 3);
 
  for (auto &b : vec)
    std::cout << b(5) << std::endl;
 
  return 0;   
}

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