I think the problem here is that you've introduced a new foo attribute with a different type. Even though the old attribute goes away in model 2, I guess it thinks this attribute in model 3 is supposed match up with the one in model 1. You can fix this by giving the new foo a renaming identifier so that it sees these are different.

I am getting this error for several Quartz libraries (Xcode 15.4 on macOS 14.4.1), but only when building for x86_64. It happens both for Objective-C and Swift targets. For Objective-C, it helped to replace imports of the Quartz umbrella framework with imports of the particular ones that I need. For Swift, I added -Xfrontend -disable-autolink-framework -Xfrontend Quartz to OTHER_SWIFT_FLAGS. Another app got this error when not even using Quartz, but it helped to disable CLANG_MODULES_AUTOLINK.

If you are using SpamSieve with the Monterey Beta 2, please update to the latest SpamSieve beta: https://forum.c-command.com/t/spamsieve-public-beta-and-macos-12-monterey/13838/10