Why does parameterized constructor with vector of strings as argument does fail to compile?

Question

In below code default constructor as well as parameterized constructor with int argument are creating temporary objects. But vector of string as a parameter to constructor is not even compiling. Can anybody explain this behavior?

#include <vector>
#include <string>

class C {                                                                                                                                                     
public:                                                                                                                                                       
    std::vector<std::string> v;                                                                                                                               
    int i;                                                                                                                                                    
    C() {                                                                                                                                                     

    }                                                                                                                                                         
    C(int j) {                                                                                                                                                
        i = j;                                                                                                                                                
    }                                                                                                                                                         

    C(std::vector<std::string> tmp) {                                                                                                                         
        v = tmp;                                                                                                                                              
    }                                                                                                                                                         
};

int main() {                                                                                                                                                  
    std::vector<std::string> v = {"Stack", "Overflow"};                                                                                                       
    C();                        // works..                                                                                                                    
    C(1);                       // works..                                                                                                                    
    C(v);                       // compilation fails..                                                                                                        
    return 0;                                                                                                                                                 
}

Below is the compilation output:

g++ -g constructor.cpp -std=c++1z
constructor.cpp: In function ‘int main()’:
constructor.cpp:25:8: error: conflicting declaration ‘C v’
     C(v);      // compilation fails..
        ^
constructor.cpp:22:27: note: previous declaration as ‘std::vector<std::__cxx11::basic_string<char> > v’
  std::vector<std::string> v = {"Stack", "Overflow"};
                           ^