c++ - Move-assignment and reference member

Question

Copy-assignment for a class with a reference member variable is a no-no because you can't reassign the reference. But what about move-assignment? I tried simply moveing it but, of course, that destroys the source object when I just want to move the reference itself:

class C
{
public:
    C(X& x) : x_(x) {}
    C(C&& other) : x_(std::move(other.x_)) {}
    C& operator=(C&& other)
    {
        x_ = std::move(other.x_);
    }
private:
    X& x_;
};

X y;
C c1(y);

X z;
C c2(z);

c2 = c1; // destroys y as well as z

Should I just not be implementing move-assignment and sticking with move-construction only? That makes swap(C&, C&) hard to implement.

Answer 1

(Posted as an answer from comment as suggested by the OP)

In general if one wants to do non-trivial stuff with references in C++, one would be using reference_wrapper<T>, which is essentially a fancy value-semantic stand-in for a T&, then one would be done with it - it already provides (re)assignment and other operations. I'm sure that would make move constructor and assignment near-trivial, if not trivial (note not trivial as in per the is_trivially_* semantics).

"Reference wrapper" is added to C++03 as part of TR1, and is part of C++11.

Documentation: http://en.cppreference.com/w/cpp/utility/functional/reference_wrapper