What I was hoping you'd say :)

This is fine until I want to do this, at which point C++ becomes a memory management bastard:

    void f(int n, int x) {
        Gadget g = new Gadget(n);
        // ...
        if (x < 100) throw new GadgetException("Gadget broke", x);
        if (x < 200) return;
        // ...
    }

    Gadget g = new Gadget(n);

That code won't compile unless Gadget has an assignment operator that accepts a pointer, which is, well, not a very common scenario.

Note: I'm not trying to be nitpicky. I really don't understand what you mean when you write that you "want to do this".

Now, I don't know anything about you, but based off your comments in this thread I'm not sure you have a working knowledge of C++.

you can always fake a defer:

    void f(int n, int x) {
      Gadget g = new Gadget(n);
      std::shared_ptr<void> defer(nullptr, [g](void *) {
        delete g;
      });
    ...

But honestly ... I'd just use a stack allocated object - or a smart pointer. In the last year I didn't write one delete. (I'm a full time C++ dev).

Well, what's easy in Java here is that you're effectively always working with shared objects. That's easy to use, but in my experience quite error prone, I can't count how many memory leaks I fixed in Java/JS code. YMMV.

In C++, you have various ways of referencing and passing objects, so you need to be aware of the lifetime and ownership of objects. It's arguably harder, and unfortunately, the C heritage makes it a lot harder than it needs to be :(

This code makes no sense. I think you do not understand C++ very well.

isn't that illegal?