Right now we don't use any Obj-C 2.0 language features, AFAIK. Wikipedia has a basic overview of the new features: http://en.wikipedia.org/wiki/Objective-C#Objective-C_2.0 I'm not interested in Obj-C garbage collection right now, but we might want to allow use of fast enumeration ("in") and properties. This bug is about deciding whether or not we're going to allow use of Obj-C 2.0 language features in our code going forward. Anyone know of any reason why fast enumeration, properties, or any other 2.0 language feature wouldn't be safe?

Do we know that Objective-C 2.0 garbage collection can be turned off?

(In reply to comment #1) > Do we know that Objective-C 2.0 garbage collection can be turned off? It is off by default. I think you use "-fobjc-gc-only" or "-fobjc-gc" to turn it on when compiling.

I'm curious if/how these features would benefit us in practice? The article mentions better performance and the syntax is better. We are not really bound on iterating performance. Will we need to use these features to use any future APIs?

I doubt we need any of this, but in some cases it might make our code easier to read. If there is no good reason not to use these things then we should probably allow it. I've reviewed a couple of patches now in which people attempted to use fast enumeration - I don't want to continue to say no to that if it's fine. Bug 660586 is a good example.

After spending more time reading the docs and talking to people I don't see any reason not to allow Obj-C 2.0 language features (no GC though). I'm going to mark this bug as fixed, if anyone comes up with issues please raise them here.