RE: setq's with missing final arguments.

[Drew Adams]

> (defun bad-setq ()
>   "Doc string"
>   (setq foo 5
>       bar))
> In the setq, there is a missing argument after "bar".  At the moment,
> the byte compiler just generates code to assign nil to bar, without
> giving any warning.  IMAO, this is Very Bad.
> I propose to insert code into the byte compiler to detect and warn of
> this scenario:

It's not just the byte-compiler.  This is the (erroneous, IMO)
behavior of `setq', whether interpreted or byte-compiled:

(setq bar) ; bar := nil

(setq bar) should raise an error.  The doc says that `setq'
requires an even number of args.  Same thing in other Lisps
(e.g., Common Lisp).