Are associative arrays stable in D?

[Gary Willoughby]

Are associative arrays stable in D? I have to ask because i'm 
having a great deal of problems with them for simple operations. 
For example the following crashes.

import std.stdio;
void main(string[] args)
{
        int[string] waiting;

        waiting["gary"] = 1;
        waiting["tess"] = 2;

        foreach (string key; waiting.byKey())
        {
                writeln(key);
                writeln(waiting[key]);
                waiting.remove(key);
        }
}

If however you remove the .byKey() call and use .keys instead, it 
works!

Also if you remove the 'writeln(waiting[key]);' line from the 
above code it prints about 40 blank lines.