int i =2;
double &r =i;
r = 3;
cout << i << endl;
cout << r << endl;
will report
error: non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'
But
int i =2;
double &&r =i;
r = 3;
cout << i << endl;
cout << r << endl;
just works fine.
The reason is that implicit typecast has created a anonymous(rvalue) variable.
