Copy-constructor from superclass

I have the following code:

#include <iostream>
#include <utility>

class A {
public:
    A() { }
    A(const A&, int i) { std::cout << "A copy" << std::endl; }
    A(A&&, int i) { std::cout << "A move" << std::endl; }
    A(const A&) = delete;
    A(A&&) = delete;
};

class B : public A {
public:
    B(int i) { std::cout << "B construct" << std::endl; }
    B(const A& a) : A(a, 1) { std::cout << "B copy" << std::endl; }
    B(A&& a) : A(std::move(a), 1) { std::cout << "B move" << std::endl; }
};


B make_b() {
    return B(1);
}

int main() {
    B b = make_b();
}

The compiler error reports the error that B cannot be copy-constructed (for return from make_b), because it has no copy-constructor, because A's copy-constructor is deleted.

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• Does B(const A&) not qualify as copy-constructor, and what is the rule that applies here?


• Does the copy and move constructor always have to take one argument of the same type (and not a superclass)?


• Can it have additional parameters with default values?


• Can it be templated so that it can resolve to a valid copy constructor?


• To allow implicit copy and move construction, is it necessary to explicitly add copy and move-constructors B(const B&) and B(B&&)?