modernize-use-equals-delete

This check marks unimplemented private special member functions with = delete. To avoid false-positives, this check only applies in a translation unit that has all other member functions implemented.

struct A {
private:
  A(const A&);
  A& operator=(const A&);
};

// becomes

struct A {
private:
  A(const A&) = delete;
  A& operator=(const A&) = delete;
};