Delegate is left with a destroyed stack object

[Ali Çehreli]

Continuing the conversation from the following thread:

   http://forum.dlang.org/post/l4mi8l$1r1$1@digitalmars.com

(Note: The OP's example there behaves as expected on git head.)

The programmer thinks that the following delegate returned by foo() will 
print S(1) because the delegate uses the local 's' which is supposed to 
live long enough:

import std.stdio;

struct S
{
     int i;
     ~this() { i = 666; }
}

auto foo()
{
     S s = S(1);
     return { writeln(s); } ;  // <-- Uses local s
}

void main()
{
     foo()();
}

However, 's' gets destroyed upon leaving foo() and the delegate is left 
with a destroyed object; so the program prints S(666).

Is that by design or a bug?

Aside: Never mind that the destroyed object gets destroyed again, and 
again, and again. :) (Well, presumably after being copied to other 
object in its dead state, because the address of the object is not the 
same.) (Put a writeln() inside the destructor to see that in action.)

Ali