[swift5] Fix Xcode 16 compilation crash with Extensions.swift generation

[lilidotshi]

This PR aims to address #19459 with the solution provided by @borsosbe.

Mentioning swift tech commitee: @dydus0x14 @4brunu @jgavris @ehyche @Edubits @jaz-ah for visibility into the issue.

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.6.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

[aehlke]

This is important to get merged

[borsosbe]

@lilidotshi Great, thanks!

[4brunu]

Thanks for your PR

[tcollins590]

This seems to break alamofire generation using --library alamofire

[4brunu]

Hi @tcollins590 can you elaborate on the problem you are having?

[lilidotshi]

@4brunu I noticed that Xcode 16's release notes say that they have officially fixed this issue, do you see any reason to revert this PR back to its original?

[4brunu]

If reverting this PR fixes the issue and works with Xcode 16, for me we can revert this.
Can someone try the old code with Xcode 16 to confirm that reverting this PR fixes the issue?

[r3econ]

I tried it out in the morning. The old code does not work with Xcode 16.

[4brunu]

And what is the issue with the new code?
Can someone give more details on that?

[tcollins590]

@4brunu I'll dig deeper into the errors I was running into and report back

[lilidotshi]

Also, what version are you using @tcollins590. @4brunu has a release with this patch even come out yet?

[4brunu]

No, not yet

[tcollins590]

@lilidotshi I was using the branch that this PR merged into. The issue came up with using --library alamofire I'll run it again in a bit.