I have c++ enabled in my project and they build fine in Xcode 16.2. But now iOS SDK c++ files do not compile since “std::char_traits” support has been dropped from compiler during 16.3 update. This is the error I get: /Developer/SDKs/iPhoneOS18.4.sdk/usr/include/c++/v1/ios:543:64 Implicit instantiation of undefined template 'std::char_traits' At least these are broken, maybe more: ios.h basic_ostream.h string.h string_view.h This is rather annoying that Apple's own header files do not compile. Can't fix it by myself. Also other workarounds than downgrading to 16.2 are welcome. Feedback assistant: FB17183862

Upgrading to Xcode 16.3, all previews across my AppKit project stopped working. The error message I'm getting is especially baffling. It says the project could not be built with incremental compilation because SWIFT_COMPILATION_MODE is set to "incremental": I tried clearing DerivedData with no effect. When I click the diagnostics button the information given is not very revealing, at least not to me. If I open the project in Xcode 16.2 everything works perfectly again. I switched over to Previews for all new code but this error situation is quite demotivating. Does anyone have any suggestions?