Fix Issue 18429 - alias this enum causes segmentation fault

[RazvanN7]

If the identifier in the alias this declaration is defined later and is a voldemort type, we must perform semantic on the declaration to deduce the type.

[dlang-bot]

Thanks for your pull request and interest in making D better, @RazvanN7! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.
Please verify that your PR follows this checklist:

• My PR is fully covered with tests (you can see the annotated coverage diff directly on GitHub with CodeCov's browser extension
• My PR is as minimal as possible (smaller, focused PRs are easier to review than big ones)
• I have provided a detailed rationale explaining my changes
• New or modified functions have Ddoc comments (with Params: and Returns:)

Please see CONTRIBUTING.md for more information.

---

If you have addressed all reviews or aren't sure how to proceed, don't hesitate to ping us with a simple comment.

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	18429	normal	alias this enum causes segmentation fault

[JinShil]

Instead of writing "Fix Issue 18429", I suggest just pasting the issue URL. It has the issue number in it, and gives the reader of the code immediate access the the issue.

[RazvanN7]

Done.

[stefan-koch-sociomantic]

This might be indicative of other problems, I'd be on the look out for other places where the type is not set is not called.

[WalterBright]

It would be nice to merge the test case into another file in the compilable directory, since fewer files make the autotester go faster.

[WalterBright]

BTW @RazvanN7 thanks for the quick action on this bug!

[JinShil]

The error in automem may be legitimate. I restarted Jenkins to see if it's reproducible.

UPDATE: Yep, look likes this may cause a regression. See the automem test in Jenkins.

[RazvanN7]

@WalterBright

It would be nice to merge the test case into another file in the compilable directory, since fewer files make the autotester go faster.

Done.

@JinShil

Indeed, it was a regression, but I fixed it now.

[wilzbach]

UPDATE: Yep, look likes this may cause a regression. See the automem test in Jenkins.
Indeed, it was a regression, but I fixed it now.

Wow. We added automem to the Projects Tester three days ago. I think @atilaneves will like this ;-)

[atilaneves]

@wilzbach Can't complain ;)