Yield from function?

[Profile Anaysis via Digitalmars-d-learn]

On Monday, 30 January 2017 at 18:48:10 UTC, Ali Çehreli wrote:
> On 01/30/2017 03:03 AM, Profile Anaysis wrote:
> > I need to yield from a complex recursive function too allow
> visualizing
> > what it is doing.
> >
> > e.g., if it is a tree searching algorithm, I'd like to yield
> for each
> > node so that the current state can be shown visually.
>
> I used tree iteration as a Generator example here:
>
>   http://ddili.org/ders/d.en/fibers.html
>
> It's in the code where the function 'byNode' appears. (The 
> example builds on an earlier tree iteration code in the same 
> chapter.)
>
> Ali

I tried your lambda based fib example and it works as 
expected(using a function)

But when I try the class version it crashes without a call stack 
or any info(somewhere in the fiber module and an access 
violation).

import std.stdio, std.concurrency, core.thread;

class Search : Fiber
{
     this() { super(&start); }
     int res = 0;
     void start()
     {			
	Fiber.yield();
         res = 1;
     }
}

void main()
{

	auto search = new Search();

	search.call(); writeln(search.res);
	search.call(); writeln(search.res);
	search.call(); writeln(search.res); // crashes after 3rd 
call(first two work fine)
}


Any ideas what why it is crashing like this?