3 files changed, 12 insertions, 3 deletions
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index da5ebc2a256..05a76a71a44 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1780,6 +1780,8 @@ def ext_forward_ref_enum : Extension<
   "ISO C forbids forward references to 'enum' types">;
 def err_forward_ref_enum : Error<
   "ISO C++ forbids forward references to 'enum' types">;
+def ext_ms_forward_ref_enum : Extension<
+  "forward references to 'enum' types are a Microsoft extension">, InGroup<Microsoft>;
 def ext_forward_ref_enum_def : Extension<
   "redeclaration of already-defined enum %0 is a GNU extension">, InGroup<GNU>;
   
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e4dca2ba980..21b328d64ce 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5755,9 +5755,12 @@ CreateNewDecl:
           << New;
         Diag(Def->getLocation(), diag::note_previous_definition);
       } else {
-        Diag(Loc, 
-             getLangOptions().CPlusPlus? diag::err_forward_ref_enum
-                                       : diag::ext_forward_ref_enum);
+        unsigned DiagID = diag::ext_forward_ref_enum;
+        if (getLangOptions().Microsoft)
+          DiagID = diag::ext_ms_forward_ref_enum;
+        else if (getLangOptions().CPlusPlus)
+          DiagID = diag::err_forward_ref_enum;
+        Diag(Loc, DiagID);
       }
     }
   } else {
diff --git a/clang/test/SemaCXX/MicrosoftExtensions.cpp b/clang/test/SemaCXX/MicrosoftExtensions.cpp
index 93650a53f44..7cc1675f2e7 100644
--- a/clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ b/clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -84,3 +84,7 @@ void m1() {
   h1<int>(&M::addP);
   h1(&M::subtractP);
 } 
+
+//MSVC allows forward enum declaration
+enum ENUM; // expected-warning {{forward references to 'enum' types are a Microsoft extension}}
+ENUM *var;