Re: puzzling byte-compile-file message: `=' called for effect

[Jim Ottaway <j.ottaway@lse.ac.uk>]

>>>>> Drew Adams <drew.adams@oracle.com> writes:

> The term "for effect" is correct here, but I don't think it is as clear as
> it could be. The compiler is suggesting that, if the `=' expression is
> useful, it must be useful because of side effects that occur during its
> evaluation.

> I think the compiler should explicitly say that the resulting _value_ of the
> `=' expression is not used. It might also say that the `=' expression may be
> useful for its side effects (or side effects of its subexpressions), but the
> resulting value has no effect on the overall code. At a minimum, the word
> "side" should be added to "effect".

Yes, I agree.  I was so puzzled by the elliptical message that I
missed the obvious error in my code.

> The message might better say:

>  "Warning: `=' return value ignored. Is the expression useful
>            for its side effects?"

Something like that, I agree, even simply "`=' called for side effect
alone".

> Ccing emacs-devel, as I think the message should be clarified
> somehow. 

Me too.

Regards,

-- 
Jim Ottaway