Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -4884,8 +4884,7 @@
   void ActOnFinishCXXMemberDecls();
 
   void ActOnReenterCXXMethodParameter(Scope *S, ParmVarDecl *Param);
-  void ActOnReenterTemplateScope(Scope *S, Decl *Template);
-  void ActOnReenterDeclaratorTemplateScope(Scope *S, DeclaratorDecl *D);
+  unsigned ActOnReenterTemplateScope(Scope *S, Decl *Template);
   void ActOnStartDelayedMemberDeclarations(Scope *S, Decl *Record);
   void ActOnStartDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
   void ActOnDelayedCXXMethodParameter(Scope *S, Decl *Param);
Index: lib/Parse/ParseTemplate.cpp
===================================================================
--- lib/Parse/ParseTemplate.cpp
+++ lib/Parse/ParseTemplate.cpp
@@ -1249,34 +1249,23 @@
   SmallVectorImpl<DeclContext *>::reverse_iterator II =
       DeclContextsToReenter.rbegin();
   for (; II != DeclContextsToReenter.rend(); ++II) {
-    if (ClassTemplatePartialSpecializationDecl *MD =
-            dyn_cast_or_null<ClassTemplatePartialSpecializationDecl>(*II)) {
-      TemplateParamScopeStack.push_back(
-          new ParseScope(this, Scope::TemplateParamScope));
-      Actions.ActOnReenterTemplateScope(getCurScope(), MD);
-      ++CurTemplateDepthTracker;
-    } else if (CXXRecordDecl *MD = dyn_cast_or_null<CXXRecordDecl>(*II)) {
-      bool IsClassTemplate = MD->getDescribedClassTemplate() != 0;
-      TemplateParamScopeStack.push_back(
-          new ParseScope(this, Scope::TemplateParamScope, 
-                        /*ManageScope*/IsClassTemplate));
-      Actions.ActOnReenterTemplateScope(getCurScope(),
-                                        MD->getDescribedClassTemplate());
-      if (IsClassTemplate) 
-        ++CurTemplateDepthTracker;
-    }
+    Decl *D = dyn_cast<Decl>(*II);
+
+    TemplateParamScopeStack.push_back(new ParseScope(this,
+          Scope::TemplateParamScope));
+    unsigned NumParamLists =
+      Actions.ActOnReenterTemplateScope(getCurScope(), D);
+    CurTemplateDepthTracker.addDepth(NumParamLists);
+
     TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope));
     Actions.PushDeclContext(Actions.getCurScope(), *II);
   }
   TemplateParamScopeStack.push_back(
       new ParseScope(this, Scope::TemplateParamScope));
 
-  DeclaratorDecl *Declarator = dyn_cast<DeclaratorDecl>(FunD);
-  const unsigned DeclaratorNumTemplateParameterLists = 
-      (Declarator ? Declarator->getNumTemplateParameterLists() : 0);
-  if (Declarator && DeclaratorNumTemplateParameterLists != 0) {
-    Actions.ActOnReenterDeclaratorTemplateScope(getCurScope(), Declarator);
-    CurTemplateDepthTracker.addDepth(DeclaratorNumTemplateParameterLists);
+  if (unsigned NumLists = FunD->getNumTemplateParameterLists()) {
+    Actions.ActOnReenterTemplateScope(getCurScope(), FunD);
+    CurTemplateDepthTracker.addDepth(NumLists);
   }
   Actions.ActOnReenterTemplateScope(getCurScope(), LPT.D);
   ++CurTemplateDepthTracker;
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -5980,47 +5980,41 @@
   }
 }
 
-void Sema::ActOnReenterDeclaratorTemplateScope(Scope *S, DeclaratorDecl *D) {
+unsigned Sema::ActOnReenterTemplateScope(Scope *S, Decl *D) {
   if (!D)
-    return;
+    return 0;
 
-  int NumParamList = D->getNumTemplateParameterLists();
-  for (int i = 0; i < NumParamList; i++) {
-    TemplateParameterList* Params = D->getTemplateParameterList(i);
-    for (TemplateParameterList::iterator Param = Params->begin(),
-                                      ParamEnd = Params->end();
-          Param != ParamEnd; ++Param) {
-      NamedDecl *Named = cast<NamedDecl>(*Param);
-      if (Named->getDeclName()) {
-        S->AddDecl(Named);
-        IdResolver.AddDecl(Named);
-      }
-    }
+  SmallVector<TemplateParameterList *, 4> ParameterLists;
+
+  if (TemplateDecl *TD = dyn_cast<TemplateDecl>(D))
+    ParameterLists.push_back(TD->getTemplateParameters());
+
+  if (auto *PSD = dyn_cast<ClassTemplatePartialSpecializationDecl>(D))
+    ParameterLists.push_back(PSD->getTemplateParameters());
+
+  if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
+    for (unsigned i = 0; i < DD->getNumTemplateParameterLists(); ++i)
+      ParameterLists.push_back(DD->getTemplateParameterList(i));
   }
-}
 
-void Sema::ActOnReenterTemplateScope(Scope *S, Decl *D) {
-  if (!D)
-    return;
-  
-  TemplateParameterList *Params = 0;
-  if (TemplateDecl *Template = dyn_cast<TemplateDecl>(D))
-    Params = Template->getTemplateParameters();
-  else if (ClassTemplatePartialSpecializationDecl *PartialSpec
-           = dyn_cast<ClassTemplatePartialSpecializationDecl>(D))
-    Params = PartialSpec->getTemplateParameters();
-  else
-    return;
+  if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
+    for (unsigned i = 0; i < RD->getNumTemplateParameterLists(); ++i)
+      ParameterLists.push_back(RD->getTemplateParameterList(i));
 
-  for (TemplateParameterList::iterator Param = Params->begin(),
-                                    ParamEnd = Params->end();
-       Param != ParamEnd; ++Param) {
-    NamedDecl *Named = cast<NamedDecl>(*Param);
-    if (Named->getDeclName()) {
-      S->AddDecl(Named);
-      IdResolver.AddDecl(Named);
+    if (ClassTemplateDecl *CTD = RD->getDescribedClassTemplate())
+      ParameterLists.push_back(CTD->getTemplateParameters());
+  }
+
+  for (TemplateParameterList *Params : ParameterLists) {
+    for (NamedDecl *Param : *Params) {
+      if (Param->getDeclName()) {
+        S->AddDecl(Param);
+        IdResolver.AddDecl(Param);
+      }
     }
   }
+
+  return ParameterLists.size();
 }
 
 void Sema::ActOnStartDelayedMemberDeclarations(Scope *S, Decl *RecordD) {
Index: test/Parser/DelayedTemplateParsing.cpp
===================================================================
--- test/Parser/DelayedTemplateParsing.cpp
+++ test/Parser/DelayedTemplateParsing.cpp
@@ -123,3 +123,61 @@
 
 template <typename T>
 auto invalidTrailingRetType() -> Bogus {} // expected-error {{unknown type name 'Bogus'}}
+
+namespace PR19613 {
+
+struct HeapTypeConfig {
+  static void from_bitset();
+};
+
+template <class Config>
+struct TypeImpl  {
+  struct BitsetType;
+
+  static void Any() {
+    BitsetType::New();
+  }
+};
+
+template<class Config>
+struct TypeImpl<Config>::BitsetType {
+  static void New() {
+    Config::from_bitset();
+  }
+};
+
+static void f() {
+  TypeImpl<HeapTypeConfig>::Any();
+}
+
+template<typename A> struct S {
+  template<typename B> struct T;
+};
+template<typename A> template<typename B> struct S<A>::T {
+  template<typename C, typename D> struct U;
+  template<typename C> struct U<C, C> {
+    template<typename E> static int f() {
+      return sizeof(A) + sizeof(B) + sizeof(C) + sizeof(E);
+    }
+  };
+};
+
+static void g() {
+  S<int>::T<int>::U<int,int>::f<int>();
+}
+
+template<typename T> struct SS {
+  template<typename U> struct X;
+  template<typename U> struct X<U*>;
+};
+template<typename T> template<typename U> struct SS<T>::X<U*> {
+  static int f() {
+    return sizeof(T) + sizeof(U);
+  }
+};
+
+static void h() {
+  SS<int>::X<int*>::f();
+}
+
+}