[PATCH] D57438: [Sema][ObjC] Allow declaring ObjC pointer members in C++ unions under ARC

[Akira Hatanaka via Phabricator via cfe-commits]

ahatanak marked 2 inline comments as done.
ahatanak added inline comments.


================
Comment at: lib/Sema/SemaDeclCXX.cpp:7084
 
+  if (FD->getParent()->isUnion() &&
+      shouldDeleteForVariantObjCPtrMember(FD, FieldType))
----------------
rjmccall wrote:
> rjmccall wrote:
> > I believe the right check for variant-ness is `inUnion()`, not `FD->getParent()->isUnion()`, since the latter can miss cases with e.g. anonymous `struct`s.
> Can you try adding a test case here for an anonymous struct nested within an anonymous union?
Added a test case for an anonymous struct nested within an anonymous union (`struct S2` in arc-0x.mm).

I found out that the diagnostic messages clang prints for arc-0x.mm are the same whether `inUnion()` or `FD->getParent()->isUnion()` is called. This is what I discovered:

`SpecialMemberDeletionInfo` is used in two cases:

1. To find the deletedness of the special functions in the AST after a class is parsed.

2. When a deleted special function is used, provide more details on why the function is deleted and print note diagnostics.

Since the nested classes are parsed before the enclosing classes, we have all the information we need about the members that are directly contained to correctly infer the deletedness of a class' special functions. So the first case should work fine regardless of which method is called.

It doesn't make a difference for the second case either because `SpecialMemberDeletionInfo` doesn't try to find out which member of an anonymous struct is causing the special function to be deleted; it only does so for anonymous unions (which happens inside the if statement near comment "// Some additional restrictions exist on the variant members." at line 7140).


Repository:
  rC Clang

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  https://reviews.llvm.org/D57438/new/

https://reviews.llvm.org/D57438