[cfe-dev] Obj-C false positive warning with deprecation and instancetype?

[jahanian]

On Jan 11, 2012, at 11:57 AM, Jean-Daniel Dupas wrote:

> 
> Le 11 janv. 2012 à 20:01, jahanian a écrit :
> 
>> 
>> On Jan 11, 2012, at 10:49 AM, jahanian wrote:
>> 
>>> 
>>> On Jan 11, 2012, at 8:10 AM, Sean McBride wrote:
>>> 
>>>> Hi all,
>>>> 
>>>> Using clang r147866 on Mac OS X 10.7, the code below causes this warning:
>>>> 
>>>> $ clang -fsyntax-only test.m 
>>>> test.m:18:11: warning: 'initWithContentsOfURL:' is deprecated [-Wdeprecated-declarations]
>>>>     return [[[self alloc] initWithContentsOfURL:inURL] autorelease];
>>>>              ^
>>>> 
>>>> NSString has a deprecated method initWithContentsOfURL:, but in my own class it's not deprecated.  I would have thought that between my own use of instancetype and clang's special casing of alloc that this should not warn.  Is it a false positive bug?
>>> 
>>> It is not false positive. [self alloc] is of type 'id'. Not knowing which initWithContentsOfURL gets called, clang goes out of its way to issue the deprecated warning so user can take action.
>>> You can make your intention known to clang by type-casting [self alloc].
>>> 
>>> - Fariborz
>> 
>> 
>> If alloc is using instancetype then you shouldn't see this warning. Please file a bug report with the pre-processed file.
>> 
> 
> According to clang doc, "+alloc implicitly has a related result type". So clang should be able to determine what the return type is.

Can you point to the document? This can't be part of the 'clang' doc. 'alloc' need to use instancetype for type deduction purposes. Legacy
frameworks use 'id' for 'alloc' type.

- Fariborz
> 
> -- Jean-Daniel
> 
> 
> 
>