Exception safety guarantees

#include <iostream>
#include <string>
#include <variant>
using namespace std;
class ThrowingClass
{
public:
    explicit ThrowingClass(int i) {
        if (i == 0) throw int (10);
    }
    operator int () {
        throw int(10);
    }
};
int main(int argc, char** argv)
{
    std::variant<int, ThrowingClass> v;
// change the value:
    try
    {
        v = ThrowingClass(0);
    }
    catch (...)
    {
        std::cout << "catch(...)\n";
// we keep the old state!
        std::cout << v.valueless_by_exception() << '\n';
        std::cout << std::get<int>(v) << '\n';
    }
// inside emplace
    try
    {
        v.emplace<0>(ThrowingClass(10)); // calls the operator int
    }
    catch (...)
    {
        std::cout << "catch(...)\n";
// the old state was destroyed, so we're not in invalid state!
        std::cout << v.valueless_by_exception() << '\n';
    }
    return 0;
}