diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index c3e3149..61fd826 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -3036,7 +3036,7 @@
       return TTP->getNumExpansionTemplateParameters();
   }
 
-  return Optional<unsigned>();
+  return None;
 }
 
 /// \brief Check that the given template argument list is well-formed
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index bbf2a98..c8f0372 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -628,7 +628,7 @@
     case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation:
     case ActiveTemplateInstantiation::ExceptionSpecInstantiation:
       // This is a template instantiation, so there is no SFINAE.
-      return Optional<TemplateDeductionInfo *>();
+      return None;
 
     case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation:
     case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution:
@@ -647,7 +647,7 @@
     }
   }
 
-  return Optional<TemplateDeductionInfo *>();
+  return None;
 }
 
 /// \brief Retrieve the depth and index of a parameter pack.
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index b971a04..1515a35 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1638,9 +1638,8 @@
 }
 
 ParmVarDecl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {
-  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,
-                                  Optional<unsigned>(),
-                                  /*ExpectParameterPack=*/false);
+  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0, None,
+                                  /*ExpectParameterPack=*/ false);
 }
 
 Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(
diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 2cff7aa..c0ad2be 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -443,8 +443,7 @@
   if (!TSInfo)
     return true;
 
-  TypeSourceInfo *TSResult =
-      CheckPackExpansion(TSInfo, EllipsisLoc, Optional<unsigned>());
+  TypeSourceInfo *TSResult = CheckPackExpansion(TSInfo, EllipsisLoc, None);
   if (!TSResult)
     return true;
   
@@ -490,7 +489,7 @@
 }
 
 ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
-  return CheckPackExpansion(Pattern, EllipsisLoc, Optional<unsigned>());
+  return CheckPackExpansion(Pattern, EllipsisLoc, None);
 }
 
 ExprResult Sema::CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
@@ -662,7 +661,7 @@
         if (Instantiation->is<Decl*>())
           // The pattern refers to an unexpanded pack. We're not ready to expand
           // this pack yet.
-          return Optional<unsigned>();
+          return None;
 
         unsigned Size = Instantiation->get<DeclArgumentPack *>()->size();
         assert((!Result || *Result == Size) && "inconsistent pack sizes");
@@ -676,7 +675,7 @@
         !TemplateArgs.hasTemplateArgument(Depth, Index))
       // The pattern refers to an unknown template argument. We're not ready to
       // expand this pack yet.
-      return Optional<unsigned>();
+      return None;
     
     // Determine the size of the argument pack.
     unsigned Size = TemplateArgs(Depth, Index).pack_size();
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index d4d42cd..209699f 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -2889,7 +2889,7 @@
           << T <<  D.getSourceRange();
         D.setEllipsisLoc(SourceLocation());
       } else {
-        T = Context.getPackExpansionType(T, Optional<unsigned>());
+        T = Context.getPackExpansionType(T, None);
       }
       break;
 
@@ -2903,7 +2903,7 @@
       // parameter packs in the type of the non-type template parameter, then
       // it expands those parameter packs.
       if (T->containsUnexpandedParameterPack())
-        T = Context.getPackExpansionType(T, Optional<unsigned>());
+        T = Context.getPackExpansionType(T, None);
       else
         S.Diag(D.getEllipsisLoc(),
                LangOpts.CPlusPlus11
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 0832a24..438d06a 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -4098,8 +4098,7 @@
                                                   /*ExpectParameterPack=*/true);
       } else {
         NewParm = getDerived().TransformFunctionTypeParam(
-            OldParm, indexAdjustment, Optional<unsigned>(),
-            /*ExpectParameterPack=*/ false);
+            OldParm, indexAdjustment, None, /*ExpectParameterPack=*/ false);
       }
 
       if (!NewParm)
@@ -8565,7 +8564,7 @@
       ArgChanged = true;
 
     ObjCDictionaryElement Element = {
-      Key.get(), Value.get(), SourceLocation(), Optional<unsigned>()
+      Key.get(), Value.get(), SourceLocation(), None
     };
     Elements.push_back(Element);
   }