delegate reference

[Saaa]

>
> class Foo
> {
>  C* c;
>
>  this(ref C c)
>  {
>    this.c = &c;
>  }
>
>  int invoke()
>  {
>    return (*c).method();
>  }
> }
>
> void main()
> {
>  // ...
>  deleg = &(new Foo(c)).invoke;
> }
>
> Or something similar.
>
> This is dangerous.  Do not allow either the Foo instance or the delegate
> to survive past the end of c's scope.
>
> It is simpler and safer to just update the delegate.
Thanks!