Re: [Cocci] Checking redundant variable initialisations with SmPL?

[Markus Elfring <Markus.Elfring@web.de>]

>>> It could be helpful to replace the last line by:
>>>
>>> (
>>>   e3 = <+...var...+>
>>
>> Can this SmPL specification make sense as another when constraint?
>
> No.

I imagine that a few extensions like the following can become safer.

     when != do ds while( \( var bo e3 \| var \) );
     when != switch(var) { ... default: ... }


Unfortunately, the software combination “Coccinelle 1.0.7-00211-geaa13d59 (OCaml 4.07.1)”
does not like such an approach at the moment.

…
minus: parse error:
  File "/home/elfring/Projekte/Coccinelle/janitor/show_questionable_variable_initialisation3.cocci", line 12, column 27, charpos = 295
  around = '...',
…


If I try the specification “when != switch(var) { default: ... }” out,
the information “not supported” is provided.


> When is about the code between the code that matches what is before
> or after.  If you put when, you will get a false positives for var = var + 1.

It seems that more analysis constraints should be taken into account finally.
I find also that it should be ensured then that metavariables like “e3” and “var”
will refer to different source code.

Regards,
Markus
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