Is this a project you can share? If not here, than maybe just with Apple at https://feedbackassistant.apple.com ?

Comment by Mihai Cristescu (JIRA)

Unfortunately I can not share the project.

I will see what are the options, maybe the company could use one of the Technical Support Incident (TSI) included in the Apple Developer Enterprise Program.

Comment by Mihai Cristescu (JIRA)

Filed a bug at Feedback Assistant:

No. FB7448788

Does this reproduce with a recent swift.org snapshot toolchain? https://swift.org/download/#snapshots

Comment by Mihai Cristescu (JIRA)

Yes, I tried it today, the defect is still there. 🙁

The main project doesn't compile, but I was able to comment some code and compile the rest of the project. So I identified some files which are creating the issues.

Now, I am still trying to create a sample project with a subset of files that can be shared with you.

Unfortunately, until now I could not reproduce this defect with only a few files (which are involved), the smaller project compiles fine and the defect doesn't manifest.

I am still working on providing you a sample project.

Please let me know if the team fixes any defect in this area (Keypaths) such that I can try again with a new snapshot.

Thank you.

Comment by Mihai Cristescu (JIRA)

Hi, I am trying to compile the project with a newer snapshot.

I am getting this error:

ld: file not found: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2020-01-05-a.xctoolchain/usr/lib/clang/7.0.0/lib/darwin/libclang_rt.profile_iossim.a

Version 11.3 (11C29)
Toolchain: Swift Development Snapshot 2020-01-05 (a)

It seems the snapshots are not including these runtime libraries for platforms other than Mac OS.

A workaround (copy the version from the Xcode sdk) is described here:
https://forums.swift.org/t/undefined-symbol-isosversionatleast/29782/17

You could also try disabling profiling. I think this library dependency is due to enabling profiling.