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bug#6740: Spurious byte compiler warnings
From: |
Stefan Kangas |
Subject: |
bug#6740: Spurious byte compiler warnings |
Date: |
Wed, 18 Nov 2020 20:25:56 -0800 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> Warning: value returned from (featurep (quote cc-fix)) is unused
>>> Warning: value returned from (featurep (quote cc-fix)) is unused
>>>
>>> It is obvious that that value is indeed used. This is a bug.
>
>> The byte compiler knows that (featurep 'xemacs) is false, so
>> (and (not (featurep 'cc-fix)) ... )
>> will be false, so the featurep result is indeed unused.
>
>> If you use (and (featurep 'xemacs) (not (featurep 'cc-fix) ...
>> the warning will go away.
>
> It's one of those cases where the warning is the result of a check done
> "too late" (i.e. after some optimization), which means the check is not
> performed on the code the user sees, but on some massaged version of it.
> It's difficult to avoid them, short of removing all "code
> improvement" warnings.
(That was 10 years ago.)
I think this is a very minor issue that is likely not worth spending any
time on. In any case, it's not even clear what the fix would be or if
a different behavior would improve the situation.
Does anyone object to closing this as wontfix?
- bug#6740: Spurious byte compiler warnings,
Stefan Kangas <=