Hi,

In message "Re: #collect with block modifying receiver"
    on 03/08/29, Hal Fulton <hal9000 / hypermetrics.com> writes:

|OK, so this *really* makes me wonder what the "theoretically correct"
|behavior is.

|Matz, are you listening?? Enlighten us, please...

Ah, listen, it's undefined behavior. ;-)

To be serious, I don't want to slow down performance by defining any
exact behavior.  Don't modify the receiver while you are iterating
over it.

							matz.