Will move constructor and move assignment be generated if I default the copy constructor?

Question

I am a little confused about how best to define a copyable but not moveable class. It seems to me that deleting the move constructor is a bad idea because then I couldn't construct from a temporary. On the other hand I don't want the compiler to implicitly generate a move constructor for me that may be wrong or may lead to unexpected behavior. My question is whether the compiler is allowed to implicitly generate a move constructor for the following class:

class C {
    public:
    int i_;
    C(const C&) = default;
}

Answer 1

If the definition of a class X does not explicitly declare a move constructor, one will be implicitly declared as defaulted if and only if

• X does not have a user-declared copy constructor
• [and ...]

Since the copy constructor is user-declared (even though it is defaulted, which means it is not user-provided), a move constructor will not be implicitly declared as defaulted.

You're right that if you were to explicitly delete the move constructor, you would not be able to construct from temporaries because the deleted move constructor would be chosen by overload resolution. So the approach you have used for a copyable but not moveable class is the right one.