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Re: [Patch] PR55189 enable -Wreturn-type by default

On 05/06/2014 01:31, Joseph S. Myers wrote:
> On Wed, 4 Jun 2014, Sylvestre Ledru wrote:
>> Hello,
>> Finally, I have been able to update all tests with -Wreturn-type enabled
>> by default. AFAIK, under GNU/Linux Debian Jessie 64 bits, there is no
>> PASS->FAIL tests.
>> Now, I would like to know if I can commit that into the repository. Who
>> can review that?
>> As attachment, you will find the actual (tiny) patch.
>> I split the tests update by languages. As they are big ( 1260 files
>> changed, 1638 insertions(+), 903 deletions(-) ), I uploaded the patches
>> on my server:
> Some of those patches appear to be addressing cases where control appears 
> to reach the end of a function returning non-void, as opposed to cases 
> where the return type defaults to int. 
Do you have an example of the patches you are talking about?

> As I said in
> <>, I don't think that 
> warning is appropriate to enable by default as it catches perfectly valid 
> C90 / C99 code that avoids using extensions to annotate noreturn 
> functions.
I can try to implement that but I don't know where to start. Any clue?

> (I *do* think it's appropriate to enable by default the warning about 
> return type defaulting to int - more generally, to enable -Wimplicit-int 
> -Wimplicit-function-declaration - and the -Wreturn-type warning about a 
> return statement without a value in a function returning non-void also 
> seems appropriate to enable by default.  
I can try to enable them too by default. It seems my patches are
covering most of the tests updates.

> Warning about the absence of any
> return statement in a function returning non-void is probably also a 
> reasonable default warning from the -Wreturn-type set; it's specifically 
> the flow-based warnings that can give false positives in the absence of 
> noreturn annotations that I'm dubious about enabling by default.)

You are talking about code like this one (from Jonathan Wakely) ?

int f(int c)
    if (c)
       return 0;

Initially, I implemented -Wmissing-return to manage this case ( ) but Jason
suggested to remove that:
(I don't have a strong opinion on the subject).


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