Different behavior with user defined default constructor (only MSVC)

Question

I came across the following problem, with two classes X and Y where Y has a member of type X

If I then:

• create a vector of objects of type Y via std::vector<Y> list = {{}}
• and Y has a defaulted default constructor

One of the instances of type X will be destroyed twice. Even when using rule of three (or five).

It does not happen, if I either create the vector via {Y{}} or define a user supplied default constructor for Y.

See the console output of the following example:

#include <iostream>
#include <vector>

class X
{
public:
    X()
    {
        std::cout << "constructed " << this << std::endl;
    }
    ~X()
    {
        std::cout << "deleted " << this << std::endl;
    }
    X(const X& other)
    {
        std::cout << "copy constructed " << &other << " to " << this << std::endl;
    }
};

class Y
{
public:
    //Y(){}; // works
    Y() = default; // doesn't work
    ~Y() = default;
    Y(const Y& y) = default; // copy constructor
    Y& operator=(const Y& y) = default; // copy assignment
    // Y(Y&& other) noexcept = default; // move constructor
    // Y& operator=(Y&& other) noexcept = default; // move assignment
private:
    X x;
};

int main()
{
    std::cout << "start" << std::endl;
    std::vector<Y> list = {{}}; // doesn't work
    //std::vector<Y> list = {Y{}}; // works
    std::cout << "done" << std::endl;
    return 0;
}

Outputs

start
constructed 000000271CAFFCD0
copy constructed 000000271CAFFCD0 to 000001727F7145B0
deleted 000000271CAFFCD0
deleted 000000271CAFFCD0
done
deleted 000001727F7145B0

https://godbolt.org/z/vscP4TexE

This is only reproducable in MSVC.

Am I missing something or is this a compiler bug?

Edit

Thanks for the hint about the missing return statements. I added them, but get the same results.

I did enable warnings, but it only shows that the unreferenced inline functions are removed.

Edit 2

Since they are unused, I removed copy and move constructors and assignment operators from the example.

Edit 3

Adapted Output to the new code example. It still contains the double delete. Note that MSVC is a bit flakey on godbolt and it sometimes does not compile the example.