xCode 6 how to fix "Use of undeclared identifier" for automatic property synthesis?

Question

I'm using xCode6 Beta 3, and am running into an issue where a code which previously compiled fine (xCode 5.1.1 or xCode6 beta 2) suddenly started to give me "Use of undeclared identifier" errors when accessing an automatically synthesized instance variable:

- (void)setFinished:(BOOL)finished {
    [self willChangeValueForKey:@"isFinished"];
    _finished = finished;
    [self didChangeValueForKey:@"isFinished"];
}

//ERROR:
 Use of undeclared identifier '_finished'; did you mean 'finished'?

Adding @synthesize finished = _finished; makes the error go away, but is there a way to force xCode6 Beta 3 to use automatic property synthesis using underscore notation?

Do you also have an explicit getter method? If so, the ivar won't be auto synthesized for you any more. — rmaddy, Jul 08 '14 at 18:13
Yup, you need `@synthesize finished = _finished;` if you have both the getter and setter. This happens in earlier versions of Xcode too. — i_am_jorf, Jul 08 '14 at 18:28
Found the same problem in SDWebImage - Toolkit.. You gave already the answer: manually add a @synthesize statement - or wait until release of xcode. — ThorstenC, Jul 23 '14 at 17:55
@jeffamaphone this does not happens in earlier versions of xcode, OP probably has this error from the MWPhotoBrowser library, it used to work and compile perfectly in xcode 5, installed xcode 6 and suddenly got this error too. — Pochi, Sep 18 '14 at 09:22

score 40 · Accepted Answer · answered Sep 10 '14 at 09:40

40

At first I thought it was a beta version bug, but today I saw that this type of errors occur on the XCode 6 GM Seed also, though I'm yet to discover in which particular cases.

Anyway, the fix is to add a synthesize statement in the @implementation block, explicitly declaring the name of the ivar as well as the property:

@synthesize property = _property

answered Sep 10 '14 at 09:40

Şafak Gezer

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what to do if it is in Pods library – yasirmturk Sep 17 '14 at 11:12
1

File a bug. Or fix it and send the pod owner a PR. Or branch it. – i_am_jorf Sep 18 '14 at 16:27
5

I just had issues with CocoaPods (SDWebImageDownloaderOperation) and adding the synthesize calls solved everything!!! Thanks "drowntoge" – Chris Allinson Sep 18 '14 at 20:29
Ran into this issue on Xcode 6.1.1, only solution was to synthesize manually. – Joel Fischer Mar 06 '15 at 15:03

score 4 · Answer 2 · answered Aug 24 '15 at 09:50

4

If you have an explicit getter, automatic property synthesized will be ignored.

Then you have to use @synthesize property = _property

answered Aug 24 '15 at 09:50

Jakub Truhlář

20,070
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score 3 · Answer 3 · answered Sep 23 '14 at 09:44

3

pod update

then your can now update to 3.7.1 that has fixed this bug.

answered Sep 23 '14 at 09:44

iWill

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xCode 6 how to fix "Use of undeclared identifier" for automatic property synthesis?

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