[clang] Always emit complete debug info for types which appear as a member of a standard-layout union. (PR #224439)

[Scott Linder via cfe-commits]

slinder1 wrote:

> > > This looks like a reasonable path forward - though could you explain the motivation for the unit test coverage, rather than adding more (or the same/porting from the previous patch) lit style test coverage?
> > 
> > 
> > These tests are essentially ports of the test from #221615, and I believe (?) they are lit style. Did I put them in the wrong directory?
> 
> The changes to/introduction of CGDebugInfoTests.cpp - unit tests, rather than the other test changes that are in .cpp files (limited-ctor.cpp). (oh, I see in the old patch you had some unit test coverage in DeclTest.cpp and now that's moved to a separate file - I guess, yeah, same question there: Why is some test coverage in a unit test, and some in a lit (.cpp) test? Likely it should all be in .cpp/lit tests (the absence of an existing CGDebugINfoTests.cpp is a bit of a hint that we haven't needed/used unit testing for this sort of functionality so far))

The `isForwardDecl` check is easy, but `isCompleteType` seems like it would require a `-NOT` check which is more fragile. Or I guess the `update_test_checks` route works with a comment that the meaningful bit is the fowardDecl-ness of the composite types?

The unit version gets to actually name the checks which seems like a plus. I guess comments could do the same in the lit version, though.

https://github.com/llvm/llvm-project/pull/224439