Create new EnumDecl nodes for redeclarations of enums, linking them
together in the same way that we link RecordDecl/CXXRecordDecl nodes. 

Unify ActOnTag and ActOnTagStruct.

Fixes PR clang/2753.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61034 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 7643e4e..4628761 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -113,9 +113,11 @@
 
 EnumDecl *EnumDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
                            IdentifierInfo *Id,
-                           ScopedDecl *PrevDecl) {
+                           EnumDecl *PrevDecl) {
   void *Mem = C.getAllocator().Allocate<EnumDecl>();
-  return new (Mem) EnumDecl(DC, L, Id, PrevDecl);
+  EnumDecl *Enum = new (Mem) EnumDecl(DC, L, Id, 0);
+  C.getTypeDeclType(Enum, PrevDecl);
+  return Enum;
 }
 
 void EnumDecl::Destroy(ASTContext& C) {