Thanks for the warning! Yup, I did just run into that, but I’m still stuck. I found this post (Chapter 4 playgrounds not compiling Xcode 12.0.1), but now I get a different error:
Fatal error: ‘try!’ expression unexpectedly raised an error: Error Domain=CompilerError Code=1 “Function fragment_main is using language version 2.3 which is incompatible with this OS.” UserInfo={NSLocalizedDescription=Function fragment_main is using language version 2.3 which is incompatible with this OS.}: file N3DTransforms_Sources/Utility.swift, line 26
Searching for things like “language version” for Metal didn’t seem to give me any results on the forum, so I apologize in advance if I missed a different post on this topic.