Access Violation in @safe Code

[Matt Elkins via Digitalmars-d-learn]

Title says it; I get an access violation in code marked @safe. 
Here's a minimal example:

[code]
@safe:

struct Foo(alias Callback)
{
     ~this() {Callback();}
}

unittest
{
     uint stackVar;
     alias FooType = Foo!((){++stackVar;});

     FooType[1] foos;
     foos[0] = FooType.init;
}
[/code]

This results in:
object.Error@(0): Access Violation
----------------
0x00405E2A in pure nothrow @nogc @safe void 
test.__unittestL9_4().__lambda1() at <path>\test.d(12)
... more stack ...

Line 12 is the alias FooType line, where the delegate is defined.

Where is this coming from? Intuition says it is something to do 
with calling the delegate after the stack frame has popped and 
stackVar is unreachable, but I'm not seeing it. Wouldn't foos be 
destructed before the stack frame is gone?

I don't get the issue if I mark stackVar static, or if I don't 
perform the assignment to foos[0].