Linker error: Symbol Undefined

[Namespace]

Hey, I'm curious about this linker error:

OPTLINK (R) for Win32  Release 8.00.13
Copyright (C) Digital Mars 1989-2010  All rights reserved.
http://www.digitalmars.com/ctg/optlink.html
bar.obj(bar)
 Error 42: Symbol Undefined _D3foo1A6__dtorMFZv
--- errorlevel 1
foo.d:
----
debug import std.stdio;

struct A {
public:
        int id;

        this(int id) {
                debug writeln("CTor A with ", id);

                this.id = id;
        }

        debug ~this() {
                writeln("DTor A with ", id);
        }
}
----

bar.d
----
import foo;

void test(A a) {
        a.id++;
}

void main() {
        test(A(42));
        A a = A(23);
        test(a);
}
----

Usage:

C:\Users\Besitzer\Desktop>dmd -lib foo.d

C:\Users\Besitzer\Desktop>dmd bar.d foo.lib -debug
OPTLINK (R) for Win32  Release 8.00.13
Copyright (C) Digital Mars 1989-2010  All rights reserved.
http://www.digitalmars.com/ctg/optlink.html
bar.obj(bar)
 Error 42: Symbol Undefined _D3foo1A6__dtorMFZv
--- errorlevel 1

====
Without -debug or with 'debug' _in_ the DTor (before writeln) 
instead before the DTor works fine.