A bug with std::generator move assignment?

I was playing with `std::generator` and planning to incorporate into our project. One thing I came across is that the move assignment of `std::generator` seems not working.

The code is as follows. I have a `Request` object which is intended to be reused repeatedly. `Request` has a memeber variable `coro_` of `std::generator`, which captures the computation logic of the request. Since `Request` is recycled and reused, `std::generator` needs to be reset. When using the move assignment to reset `coro_ = Generate(num);`, the program always crashes with varying error codes.

`[1] 3545 illegal hardware instruction ./generator`

`[1] 3561 illegal hardware instruction ./generator`

`[1] 3571 illegal hardware instruction ./generator`

#include <generator>
#include <iostream>

std::generator<bool> Generate(int num)
{
    if (num < 0)
    {       
num = 0;
    }

    for (int i = 0; i < num; ++i)
    {
        co_yield false;
    }
    co_yield true;
}

class Request
{
public:
    Request()
        : coro_([]() -> std::generator<bool> { co_yield true; }()),
          iter_(coro_.begin()),
          has_stack_(true)
    {
    }

    ~Request() = default;

    bool Resume()
    {
        bool ret = *iter_;
        if (iter_ != coro_.end())
        {
            ++iter_;
        }
        return ret;
    }

    void Reset(int num)
    {
        if (has_stack_)
        {
            coro_.~generator();
        }

        coro_ = Generate(num);
        iter_ = coro_.begin();

        // Placement new
        // auto *tmp = new (&coro_) std::generator<bool>(Generate(num));
        // iter_ = tmp->begin();

        has_stack_ = true;
    }

private:
    std::generator<bool> coro_;
    std::ranges::iterator_t<decltype(coro_)> iter_;
    bool has_stack_{false};
};

int main()
{
    Request req;

    req.Reset(6);

    size_t i = 0;
    while (!req.Resume())
    {
        std::cout << "Process the req, iteration #" << i << std::endl;
        i++;
    }

    std::cout << "Req is done!" << std::endl;

    return 0;
}

The environment is WSL2. The kernel is 6.6.87.2-microsoft-standard-WSL2. The compiler is GCC 14.2.0. The interesting part is that I can circumvent the issue by using placement new (the commented code):

`new (&coro_) std::generator<bool>(Generate(num));`

I am wondering if anyone ever encountered a similar issue? Is this a bug with current GCC14?

https://redd.it/1nu7w4g
@r_cpp