[Cython] Possible bug when using cython -Wextra

[mark florisson]

On 14 February 2013 05:08, Robert Bradshaw <robertwb at gmail.com> wrote:
> On Thu, Feb 7, 2013 at 10:05 AM, Stefan Behnel <stefan_ml at behnel.de> wrote:
>> Samuele Kaplun, 07.02.2013 13:00:
>>> In data giovedì 7 febbraio 2013 12:11:47, Stefan Behnel ha scritto:
>>>>> [...]
>>>>>
>>>>> def test():
>>>>>     cdef int i
>>>>>
>>>>>     for i from 0 <= i < 10:
>>>>>         print "foo"
>>>>>
>>>>> [...]
>>>>
>>>> Yes, it actually is an unused variable in your code. There is no reference
>>>> to it, only assignments.
>>>
>>> mmh. But is it used albeit indirectly. Then what pattern would you suggest in
>>> this case (i.e. to repeat a certain body a given number of times), in order to
>>> avoid such warning?
>>
>> The normal thing to do in Python would be to use an underscore (i.e. "_")
>> as variable name. I don't think we currently special case that pattern,
>> though. Maybe we should.
>
> I agree. Done.
>
>> Or maybe we should just drop the "unused variable" warning for loop
>> variables as they actually do something and serve a purpose, even if they
>> are never referenced.
>
> +1 to this too. (Not yet done.)

Yeah, I think that's the sanest thing. I already implemented this in
Numba which bases its control flow on Cython's (because it's awesome,
thanks to Vitja :)). It simply adds a flag to NameAssignment which is
set for the ForNode's target variable.

> - Robert
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