intrusivePtr

static class Foo{
    private ControlBlock!int control;
    int i;

    this(int i)pure nothrow @safe @nogc{
        this.i = i;
    }
}
static struct Bar{
    private ControlBlock!int control;
    int i;

    this(int i)pure nothrow @safe @nogc{
        this.i = i;
    }
}

{
    auto i = IntrusivePtr!Foo.make(42);
    assert(i.useCount == 1);

    Foo foo = i.get;

    auto i2 = intrusivePtr(foo);
    assert(i.useCount == 2);
}

{
    auto i = IntrusivePtr!Bar.make(42);
    assert(i.useCount == 1);

    Bar* bar = i.element;

    auto i2 = intrusivePtr(bar);
    assert(i.useCount == 2);
}