If you can avoid defining default operations, do

Reason

It's the simplest and gives the cleanest semantics.

Example

struct Named_map {
public:
    explicit Named_map(const string& n) : name(n) {}
    // no copy/move constructors
    // no copy/move assignment operators
    // no destructor
private:
    string name;
    map<int, int> rep;
};

Named_map nm("map"); // construct
Named_map nm2 {nm};  // copy construct

Since std::map and string have all the special functions, no further work is needed.

Note

This is known as "the rule of zero".

Enforcement

(Not enforceable) While not enforceable, a good static analyzer can detect patterns that indicate a possible improvement to meet this rule. For example, a class with a (pointer, size) pair of members and a destructor that deletes the pointer could probably be converted to a vector.