Const引用为类成员

即使这个话题在这里被讨论了很多次,我也找不到关于我的具体案例的结论性解释。将 const 延长的使用寿命 RefTest 短暂的下面的例子合法吗?

#include <iostream>

class RefTest
{
public:
    RefTest(const std::string &input) : str(input) {}
    ~RefTest () {std::cout << "RefTest" << std::endl;}
private:
    std::string str;
};

class Child
{
public:
    Child (const RefTest &ref) : ref_m(ref) {}
    ~Child () {std::cout << "Test" << std::endl;}
private:
    const RefTest &ref_m;
};

class Test
{
public:
    Test () : child(RefTest("child")) {}//Will the temporary get destroyed here?
    ~Test () {std::cout << "Test" << std::endl;}
private:
    const Child child;
};

int main ()
{
   Test test;
}