[PATCH] D55659: [Sema][ObjC] Disallow non-trivial C struct fields in unions

[Akira Hatanaka via Phabricator via cfe-commits]

ahatanak created this revision.
ahatanak added a reviewer: rjmccall.
ahatanak added a project: clang.
Herald added subscribers: dexonsmith, jkorous.

This patch fixes a bug where clang doesn’t reject union fields of non-trivial struct types:

  struct S0 {
    id x;
  };
  
  struct S1 {
    id y;
  };
  
  union U0 {
    struct S0 s0;  // no diagnostics.
    struct S1 s1;  // no diagnostics.
  };
  
  union U1 {
    id x;  // clang rejects ObjC pointer fields in unions.
  };
  
  void test(union U0 a) {
    // Both ‘S0::x’ and ‘S1::y' are destructed in the IR.
  }

rdar://problem/46677858


Repository:
  rC Clang

https://reviews.llvm.org/D55659

Files:
  include/clang/AST/Type.h
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/Sema/SemaDecl.cpp
  test/SemaObjC/arc-decls.m
  test/SemaObjCXX/objc-weak.mm

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