Fix half of PR26048. We don't yet diagnose the case where the anonymous union member is declared first and the tag name is declared second.

llvm-svn: 256979

clang/lib/Sema/SemaDecl.cpp

@@ -3962,9 +3962,6 @@ static bool CheckAnonMemberRedeclaration(Sema &SemaRef,
                  Sema::ForRedeclaration);
   if (!SemaRef.LookupName(R, S)) return false;
 
-  if (R.getAsSingle<TagDecl>())
-    return false;
-
   // Pick a representative declaration.
   NamedDecl *PrevDecl = R.getRepresentativeDecl()->getUnderlyingDecl();
   assert(PrevDecl && "Expected a non-null Decl");
@@ -4675,11 +4672,13 @@ bool Sema::DiagnoseClassNameShadow(DeclContext *DC,
                                    DeclarationNameInfo NameInfo) {
   DeclarationName Name = NameInfo.getName();
 
-  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC)) 
-    if (Record->getIdentifier() && Record->getDeclName() == Name) {
-      Diag(NameInfo.getLoc(), diag::err_member_name_of_class) << Name;
-      return true;
-    }
+  CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC);
+  while (Record && Record->isAnonymousStructOrUnion())
+    Record = dyn_cast<CXXRecordDecl>(Record->getParent());
+  if (Record && Record->getIdentifier() && Record->getDeclName() == Name) {
+    Diag(NameInfo.getLoc(), diag::err_member_name_of_class) << Name;
+    return true;
+  }
 
   return false;
 }

clang/test/CXX/class/class.mem/p13.cpp

@@ -58,12 +58,12 @@ struct X3a {
 };
 
 // - every member of every anonymous union that is a member of class T.
-struct X4 {
+struct X4 { // expected-note{{previous}}
   union {
     int X;
     union {
       float Y;
-      unsigned X4; // expected-error{{member 'X4' has the same name as its class}}
+      unsigned X4; // expected-error{{redeclares 'X4'}}
     };
   };
 };

clang/test/CXX/class/class.union/class.union.anon/p1.cpp

@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -verify %s
+
+struct X {
+  int a; // expected-note {{previous}}
+  void b(); // expected-note {{previous}}
+  struct c; // expected-note {{previous}}
+  typedef int d; // expected-note {{previous}}
+
+  union {
+    int a; // expected-error {{member of anonymous union redeclares}}
+    int b; // expected-error {{member of anonymous union redeclares}}
+    int c; // expected-error {{member of anonymous union redeclares}}
+    int d; // expected-error {{member of anonymous union redeclares}}
+    int e; // expected-note {{previous}}
+    int f; // expected-note {{previous}}
+    int g;
+    int h; // expected-note {{previous}}
+  };
+
+  int e; // expected-error {{duplicate member}}
+  void f(); // expected-error {{redefinition}}
+  // FIXME: This is ill-formed, even though one name is a tag and the other is
+  // an anonymous union member. Reject this.
+  struct g;
+  typedef int h; // expected-error {{redefinition}}
+};

clang/test/SemaCXX/anonymous-union.cpp

@@ -62,11 +62,11 @@ void test_unqual_references(X x, const X xc) {
 
 struct Redecl {
   int x; // expected-note{{previous declaration is here}}
-  class y { };
+  class y { }; // expected-note{{previous declaration is here}}
 
   union {
     int x; // expected-error{{member of anonymous union redeclares 'x'}}
-    float y;
+    float y; // expected-error{{member of anonymous union redeclares 'y'}}
     double z; // expected-note{{previous declaration is here}}
     double zz; // expected-note{{previous definition is here}}
   };