Alan Mackenzie [2022-10-18 17:06 +0000] wrote:
> On Tue, Oct 18, 2022 at 19:34:08 +0300, Basil L. Contovounesios wrote:
>> Alan Mackenzie [2022-10-18 15:01 +0000] wrote:
>> > The problem here seems to be feeding macroexp-warn-and-return with data
>> > as the FORM argument.
>> That's not the problem, because it's just for illustrative purposes.
>> Instead of 'arg' being passed unchanged as the FORM argument, it could
>> just as well have been `(my-frobnicate ,arg).
>
> That would not loop, since there is a symbol with position there.
>
>> > FORM is intended only to be an executable lisp form.
>> `(my-frobnicate ,arg) fits that bill, right?  The end result is the
>> same: macroexp-warn-and-return is fed a form containing a cycle, without
>> any of the code that gives rise to the form being circular itself.
>
> This would not loop.

And yet: