Revert 132332 (Microsoft friend as a forward declaration), John McCall pointed out a better/simpler way to do it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132369 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Sema/Sema.h

@@ -1084,11 +1084,6 @@ public:
                  bool &OwnedDecl, bool &IsDependent, bool ScopedEnum,
                  bool ScopedEnumUsesClassTag, TypeResult UnderlyingType);
 
-  void InjectMicrosoftFriendForwardDeclaration(unsigned TagSpec,
-                                               SourceLocation KWLoc,
-                                               IdentifierInfo *Name,
-                                               SourceLocation NameLoc);
-
   Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                                 unsigned TagSpec, SourceLocation TagLoc,
                                 CXXScopeSpec &SS,

lib/Sema/SemaDecl.cpp

@@ -6631,42 +6631,6 @@ bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
   return false;
 }
 
-/// InjectMicrosoftFriendForwardDeclaration - For compatibility with MSVC,
-/// a friend declaration also act as a forward declaration if the tag name
-/// is not already declared. The tag name is declared in the next outermost
-/// non record scope.
-/// Example:
-///
-/// class A {
-///   friend class B;
-///   B* b;
-///  };
-///  B* global_b;
- 
-void Sema::InjectMicrosoftFriendForwardDeclaration(unsigned TagSpec,
-                                                   SourceLocation KWLoc,
-                                                   IdentifierInfo *Name,
-                                                   SourceLocation NameLoc) {
-  NamedDecl *N = LookupSingleName(getCurScope(), Name, NameLoc,
-                                  Sema::LookupTagName);
-  if (!N) {
-    DeclContext *ContextToAdd = CurContext;
-    while (ContextToAdd->isRecord())
-      ContextToAdd = ContextToAdd->getParent();
-
-    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
-    TagDecl *New = CXXRecordDecl::Create(Context, Kind, ContextToAdd, KWLoc,
-                                         NameLoc, Name, 0);
-    // Recreate the DeclContext.
-    ContextRAII SavedContext(*this, ContextToAdd);
-    if (getCurScope()->getFnParent())
-      PushOnScopeChains(New, getScopeForContext(ContextToAdd), true);
-    else
-      ContextToAdd->addDecl(New);
-  } 
-}
-
-
 /// ActOnTag - This is invoked when we see 'struct foo' or 'struct {'.  In the
 /// former case, Name will be non-null.  In the later case, Name will be null.
 /// TagSpec indicates what kind of tag this is. TUK indicates whether this is a
@@ -6684,9 +6648,6 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
          "Nameless record must be a definition!");
   assert(TemplateParameterLists.size() == 0 || TUK != TUK_Reference);
 
-  if (getLangOptions().Microsoft && TUK == Sema::TUK_Friend)
-    InjectMicrosoftFriendForwardDeclaration(TagSpec, KWLoc, Name, NameLoc);
-
   OwnedDecl = false;
   TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
 

test/SemaCXX/MicrosoftExtensions.cpp

@@ -226,29 +226,4 @@ private:
   using B::f; // expected-warning {{using declaration refers to inaccessible member 'ms_using_declaration_bug::B::f', which refers to accessible member 'ms_using_declaration_bug::A::f', accepted for Microsoft compatibility}}
 };
 
-}
-
-
-
-namespace friend_as_a_forward_decl {
-
-class A {
-  class Nested {
-    friend class B;
-    B* b;
-  };
-  B* b;
-};
-B* global_b;
-
-
-void f()
-{
-  class Local {
-    friend class Z;
-    Z* b;
-  };
-  Z* b;
-}
-
 }