diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index b67c3d3..c1a6c60 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1722,9 +1722,16 @@
       // Preserve triviality.
       NewMethod->setTrivial(OldMethod->isTrivial());
 
+      // MSVC allows explicit template specialization at class scope:
+      // 2 CXMethodDecls referring to the same function will be injected.
+      // We don't want a redeclartion error.
+      bool IsClassScopeExplicitSpecialization =
+                              OldMethod->isFunctionTemplateSpecialization() &&
+                              NewMethod->isFunctionTemplateSpecialization();
       bool isFriend = NewMethod->getFriendObjectKind();
 
-      if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord()) {
+      if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord() &&
+          !IsClassScopeExplicitSpecialization) {
         //    -- Member function declarations with the same name and the
         //       same parameter types cannot be overloaded if any of them
         //       is a static member function declaration.
@@ -3226,6 +3233,7 @@
     Previous.clear();
 
   bool Redeclaration = false;
+  bool AddToScope = true;
   if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
     if (TemplateParamLists.size()) {
       Diag(D.getIdentifierLoc(), diag::err_template_typedef);
@@ -3236,7 +3244,8 @@
   } else if (R->isFunctionType()) {
     New = ActOnFunctionDeclarator(S, D, DC, R, TInfo, Previous,
                                   move(TemplateParamLists),
-                                  IsFunctionDefinition, Redeclaration);
+                                  IsFunctionDefinition, Redeclaration,
+                                  AddToScope);
   } else {
     New = ActOnVariableDeclarator(S, D, DC, R, TInfo, Previous,
                                   move(TemplateParamLists),
@@ -3248,7 +3257,8 @@
 
   // If this has an identifier and is not an invalid redeclaration or 
   // function template specialization, add it to the scope stack.
-  if (New->getDeclName() && !(Redeclaration && New->isInvalidDecl()))
+  if (New->getDeclName() && AddToScope &&
+       !(Redeclaration && New->isInvalidDecl()))
     PushOnScopeChains(New, S);
 
   return New;
@@ -4201,7 +4211,8 @@
                               QualType R, TypeSourceInfo *TInfo,
                               LookupResult &Previous,
                               MultiTemplateParamsArg TemplateParamLists,
-                              bool IsFunctionDefinition, bool &Redeclaration) {
+                              bool IsFunctionDefinition, bool &Redeclaration,
+                              bool &AddToScope) {
   assert(R.getTypePtr()->isFunctionType());
 
   // TODO: consider using NameInfo for diagnostic.
@@ -4266,6 +4277,7 @@
   FunctionTemplateDecl *FunctionTemplate = 0;
   bool isExplicitSpecialization = false;
   bool isFunctionTemplateSpecialization = false;
+  bool isDependentClassScopeExplicitSpecialization = false;
 
   if (!getLangOptions().CPlusPlus) {
     // Determine whether the function was written with a
@@ -4769,10 +4781,11 @@
     } else if (isFunctionTemplateSpecialization) {
       if (CurContext->isDependentContext() && CurContext->isRecord() 
           && !isFriend) {
-        Diag(NewFD->getLocation(), diag::err_function_specialization_in_class)
+        isDependentClassScopeExplicitSpecialization = true;
+        Diag(NewFD->getLocation(), getLangOptions().Microsoft ? 
+          diag::ext_function_specialization_in_class :
+          diag::err_function_specialization_in_class)
           << NewFD->getDeclName();
-        NewFD->setInvalidDecl();
-        return 0;
       } else if (CheckFunctionTemplateSpecialization(NewFD,
                                   (HasExplicitTemplateArgs ? &TemplateArgs : 0),
                                                      Previous))
@@ -4802,8 +4815,9 @@
     }
 
     // Perform semantic checking on the function declaration.
-    CheckFunctionDeclaration(S, NewFD, Previous, isExplicitSpecialization,
-                             Redeclaration);
+    if (!isDependentClassScopeExplicitSpecialization)
+      CheckFunctionDeclaration(S, NewFD, Previous, isExplicitSpecialization,
+                               Redeclaration);
 
     assert((NewFD->isInvalidDecl() || !Redeclaration ||
             Previous.getResultKind() != LookupResult::FoundOverloaded) &&
@@ -4984,6 +4998,18 @@
           Context.setcudaConfigureCallDecl(NewFD);
         }
       }
+  
+  // Here we have an function template explicit specialization at class scope.
+  // The actually specialization will be postponed to template instatiation
+  // time via the ClassScopeFunctionSpecializationDecl node.
+  if (isDependentClassScopeExplicitSpecialization) {
+    ClassScopeFunctionSpecializationDecl *NewSpec =
+                         ClassScopeFunctionSpecializationDecl::Create(
+                                Context, CurContext,  SourceLocation(), 
+                                cast<CXXMethodDecl>(NewFD));
+    CurContext->addDecl(NewSpec);
+    AddToScope = false;
+  }
 
   return NewFD;
 }
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 05706d7..76461a0 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -8652,10 +8652,11 @@
   }
 
   bool Redeclaration = false;
+  bool AddToScope = true;
   NamedDecl *ND = ActOnFunctionDeclarator(DCScope, D, DC, T, TInfo, Previous,
                                           move(TemplateParams),
                                           IsDefinition,
-                                          Redeclaration);
+                                          Redeclaration, AddToScope);
   if (!ND) return 0;
 
   assert(ND->getDeclContext() == DC);
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index ded3520..a7d74ce 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -4511,9 +4511,18 @@
   }
 
   if (S.CurContext->isRecord() && !IsPartialSpecialization) {
-    S.Diag(Loc, diag::err_template_spec_decl_class_scope)
-      << Specialized;
-    return true;
+    if (S.getLangOptions().Microsoft) {
+      // Do not warn for class scope explicit specialization during
+      // instantiation, warning was already emitted during pattern
+      // semantic analysis.
+      if (!S.ActiveTemplateInstantiations.size())
+        S.Diag(Loc, diag::ext_function_specialization_in_class)
+          << Specialized;
+    } else {
+      S.Diag(Loc, diag::err_template_spec_decl_class_scope)
+        << Specialized;
+      return true;
+    }
   }
 
   // C++ [temp.class.spec]p6:
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 67e2d87..830f06a 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -98,8 +98,9 @@
     // Add template arguments from a function template specialization.
     else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Ctx)) {
       if (!RelativeToPrimary &&
-          Function->getTemplateSpecializationKind() 
-                                                  == TSK_ExplicitSpecialization)
+          (Function->getTemplateSpecializationKind() == 
+                                                  TSK_ExplicitSpecialization &&
+           !Function->getClassScopeSpecializationPattern()))
         break;
           
       if (const TemplateArgumentList *TemplateArgs
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 872bb87..2554b82 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1288,7 +1288,8 @@
 
 Decl *
 TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
-                                      TemplateParameterList *TemplateParams) {
+                                      TemplateParameterList *TemplateParams,
+                                      bool IsClassScopeSpecialization) {
   FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();
   void *InsertPos = 0;
   if (FunctionTemplate && !TemplateParams) {
@@ -1493,7 +1494,8 @@
   }
 
   bool Redeclaration = false;
-  SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
+  if (!IsClassScopeSpecialization)
+    SemaRef.CheckFunctionDeclaration(0, Method, Previous, false, Redeclaration);
 
   if (D->isPure())
     SemaRef.CheckPureMethod(Method, SourceRange());
@@ -1512,7 +1514,7 @@
                             : Method);
     if (isFriend)
       Record->makeDeclVisibleInContext(DeclToAdd);
-    else
+    else if (!IsClassScopeSpecialization)
       Owner->addDecl(DeclToAdd);
   }
 
@@ -1907,6 +1909,29 @@
   return UD;
 }
 
+
+Decl *TemplateDeclInstantiator::VisitClassScopeFunctionSpecializationDecl(
+                                     ClassScopeFunctionSpecializationDecl *Decl) {
+  CXXMethodDecl *OldFD = Decl->getSpecialization();
+  CXXMethodDecl *NewFD = cast<CXXMethodDecl>(VisitCXXMethodDecl(OldFD, 0, true));
+
+  LookupResult Previous(SemaRef, NewFD->getNameInfo(), Sema::LookupOrdinaryName,
+                        Sema::ForRedeclaration);
+
+  SemaRef.LookupQualifiedName(Previous, SemaRef.CurContext);
+  if (SemaRef.CheckFunctionTemplateSpecialization(NewFD, 0, Previous)) {
+    NewFD->setInvalidDecl();
+    return NewFD;
+  }
+
+  // Associate the specialization with the pattern.
+  FunctionDecl *Specialization = cast<FunctionDecl>(Previous.getFoundDecl());
+  assert(Specialization && "Class scope Specialization is null");
+  SemaRef.Context.setClassScopeSpecializationPattern(Specialization, OldFD);
+
+  return NewFD;
+}
+
 Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,
                       const MultiLevelTemplateArgumentList &TemplateArgs) {
   TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);
@@ -2335,8 +2360,10 @@
   if (Function->isInvalidDecl() || Function->isDefined())
     return;
 
-  // Never instantiate an explicit specialization.
-  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
+  // Never instantiate an explicit specialization except if it is a class scope
+  // explicit specialization.
+  if (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
+      !Function->getClassScopeSpecializationPattern())
     return;
 
   // Find the function body that we'll be substituting.