[gcasa]

Which small changes are you referring to? We use LLVM/clang and so does Apple. We have ARC, we have properties and other features as well. Be explicit... BTW, I'm the lead maintainer, so I kind of know what is there and what isn't.

[pjmlp]

Apple uses their own fork of LLVM/clang, hence why watchOS bitcode is more stable than what the open source variant offers.

"Swift and Objective-C Interoperability" - WWDC 2015 (Nullability qualifiers, audited regions, generics, typed collections, kind of types)

https://developer.apple.com/videos/play/wwdc2015/401/

"What's New in LLVM" - WWDC 2017 (API Availability checks, ARC warnings and stronger function declarations)

https://developer.apple.com/videos/play/wwdc2017/411/

"What's New in LLVM" - WWDC 2018 (ARC updates)

https://developer.apple.com/videos/play/wwdc2018/409/

"What's New in Clang and LLVM" - WWDC 2019 (runtime optimizations)

https://developer.apple.com/videos/play/wwdc2019/409/

"Advancements in the Objective-C runtime" - WWDC 2020

https://developer.apple.com/videos/play/wwdc2020/10163/

I didn't fell to go all the way back to the WWDC 2006 when Objective-C 2.0 was announced.

Explicit enough?