diff --git a/clang/include/clang/Tooling/Syntax/Nodes.h b/clang/include/clang/Tooling/Syntax/Nodes.h
--- a/clang/include/clang/Tooling/Syntax/Nodes.h
+++ b/clang/include/clang/Tooling/Syntax/Nodes.h
@@ -100,10 +100,9 @@
   NestedNameSpecifier,
   UnknownNameSpecifier,
   GlobalNameSpecifier,
-  NamespaceNameSpecifier,
-  TypeNameSpecifier,
+  DecltypeNameSpecifier,
   IdentifierNameSpecifier,
-  TypeWithTemplateNameSpecifier
+  SimpleTemplateNameSpecifier
 };
 /// For debugging purposes.
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, NodeKind K);
@@ -208,10 +207,9 @@
   NameSpecifier(NodeKind K) : Tree(K) {}
   static bool classof(const Node *N) {
     return N->kind() == NodeKind::GlobalNameSpecifier ||
-           N->kind() == NodeKind::TypeNameSpecifier ||
-           N->kind() == NodeKind::NamespaceNameSpecifier ||
-           N->kind() == NodeKind::TypeWithTemplateNameSpecifier ||
-           N->kind() == NodeKind::UnknownNameSpecifier;
+           N->kind() == NodeKind::DecltypeNameSpecifier ||
+           N->kind() == NodeKind::IdentifierNameSpecifier ||
+           N->kind() == NodeKind::SimpleTemplateNameSpecifier;
   }
 };
 
@@ -225,28 +223,17 @@
   }
 };
 
-/// A type name specifier, it can be of the form: `type-name::` or
-/// `decltype-name::` e.g. the `string::` in `std::string::size` or the
-/// `decltype(s)::` in `decltype(s)::size`.
-class TypeNameSpecifier final : public NameSpecifier {
+/// A name specifier holding a decltype, of the form: `decltype ( expression )
+/// ::` e.g. the `decltype(s)::` in `decltype(s)::size`.
+class DecltypeNameSpecifier final : public NameSpecifier {
 public:
-  TypeNameSpecifier() : NameSpecifier(NodeKind::TypeNameSpecifier) {}
+  DecltypeNameSpecifier() : NameSpecifier(NodeKind::DecltypeNameSpecifier) {}
   static bool classof(const Node *N) {
-    return N->kind() == NodeKind::TypeNameSpecifier;
+    return N->kind() == NodeKind::DecltypeNameSpecifier;
   }
 };
 
-/// A namespace name specifier, of the form `namespace-name::`
-/// e.g. the `std::` in `std::vector<int>::size`.
-class NamespaceNameSpecifier final : public NameSpecifier {
-public:
-  NamespaceNameSpecifier() : NameSpecifier(NodeKind::NamespaceNameSpecifier) {}
-  static bool classof(const Node *N) {
-    return N->kind() == NodeKind::NamespaceNameSpecifier;
-  }
-};
-
-/// A dependent type name specifier, of the form `namespace-name::`
+/// A identifier name specifier, of the form `identifier ::`
 /// e.g. the `std::` in `std::vector<int>::size`.
 class IdentifierNameSpecifier final : public NameSpecifier {
 public:
@@ -257,23 +244,15 @@
   }
 };
 
-/// A type name specifier coming from a template instantiation.
-/// e.g. the `vector<int>::` in `std::vector<int>::size`.
-class TypeWithTemplateNameSpecifier final : public NameSpecifier {
-public:
-  TypeWithTemplateNameSpecifier()
-      : NameSpecifier(NodeKind::TypeWithTemplateNameSpecifier) {}
-  static bool classof(const Node *N) {
-    return N->kind() == NodeKind::TypeWithTemplateNameSpecifier;
-  }
-};
-
-/// A name specifier we don't support yet
-class UnknownNameSpecifier final : public NameSpecifier {
+/// A name specifier with a simple-template-id, of the form `template_opt
+/// identifier < template-args > ::` e.g. the `vector<int>::` in
+/// `std::vector<int>::size`.
+class SimpleTemplateNameSpecifier final : public NameSpecifier {
 public:
-  UnknownNameSpecifier() : NameSpecifier(NodeKind::UnknownNameSpecifier) {}
+  SimpleTemplateNameSpecifier()
+      : NameSpecifier(NodeKind::SimpleTemplateNameSpecifier) {}
   static bool classof(const Node *N) {
-    return N->kind() == NodeKind::UnknownNameSpecifier;
+    return N->kind() == NodeKind::SimpleTemplateNameSpecifier;
   }
 };
 
diff --git a/clang/lib/Tooling/Syntax/BuildTree.cpp b/clang/lib/Tooling/Syntax/BuildTree.cpp
--- a/clang/lib/Tooling/Syntax/BuildTree.cpp
+++ b/clang/lib/Tooling/Syntax/BuildTree.cpp
@@ -744,23 +744,37 @@
     return true;
   }
 
-  syntax::NameSpecifier *
-  BuildNameSpecifier(NestedNameSpecifier::SpecifierKind K) {
-    switch (K) {
+  bool isDecltype(const Type &T) {
+    return T.getTypeClass() == Type::TypeClass::Decltype;
+  }
+
+  bool isTemplateInstantiation(const Type &T) {
+    return T.getTypeClass() == Type::TypeClass::TemplateSpecialization ||
+           T.getTypeClass() == Type::TypeClass::DependentTemplateSpecialization;
+  }
+
+  syntax::NameSpecifier *BuildNameSpecifier(const NestedNameSpecifier &NNS) {
+    switch (NNS.getKind()) {
     case clang::NestedNameSpecifier::Global:
       return new (allocator()) syntax::GlobalNameSpecifier;
     case clang::NestedNameSpecifier::Namespace:
     case clang::NestedNameSpecifier::NamespaceAlias:
-      return new (allocator()) syntax::NamespaceNameSpecifier;
-    case clang::NestedNameSpecifier::TypeSpec:
-      return new (allocator()) syntax::TypeNameSpecifier;
-    case clang::NestedNameSpecifier::TypeSpecWithTemplate:
-      return new (allocator()) syntax::TypeWithTemplateNameSpecifier;
     case clang::NestedNameSpecifier::Identifier:
       return new (allocator()) syntax::IdentifierNameSpecifier;
+    case clang::NestedNameSpecifier::TypeSpecWithTemplate:
+      return new (allocator()) syntax::SimpleTemplateNameSpecifier;
+    case clang::NestedNameSpecifier::TypeSpec: {
+      const auto *NNSType = NNS.getAsType();
+      assert(NNSType);
+      if (isDecltype(*NNSType))
+        return new (allocator()) syntax::DecltypeNameSpecifier;
+      if (!isTemplateInstantiation(*NNSType))
+        return new (allocator()) syntax::IdentifierNameSpecifier;
+      return new (allocator()) syntax::SimpleTemplateNameSpecifier;
+    }
     case clang::NestedNameSpecifier::Super:
       // FIXME: Support Microsoft's __super
-      return new (allocator()) syntax::UnknownNameSpecifier;
+      assert(false && "We don't yet treat the __super specifier");
     }
   }
 
@@ -792,7 +806,9 @@
     if (!QualifierLoc)
       return nullptr;
     for (auto it = QualifierLoc; it; it = it.getPrefix()) {
-      auto *NS = BuildNameSpecifier(it.getNestedNameSpecifier()->getKind());
+      const auto *NNS = it.getNestedNameSpecifier();
+      assert(NNS);
+      auto *NS = BuildNameSpecifier(*NNS);
       Builder.foldNode(Builder.getRange(getLocalSourceRange(it)), NS, nullptr);
       Builder.markChild(NS, syntax::NodeRole::NestedNameSpecifier_specifier);
     }
diff --git a/clang/lib/Tooling/Syntax/Nodes.cpp b/clang/lib/Tooling/Syntax/Nodes.cpp
--- a/clang/lib/Tooling/Syntax/Nodes.cpp
+++ b/clang/lib/Tooling/Syntax/Nodes.cpp
@@ -118,16 +118,12 @@
     return OS << "MemberPointer";
   case NodeKind::GlobalNameSpecifier:
     return OS << "GlobalNameSpecifier";
-  case NodeKind::NamespaceNameSpecifier:
-    return OS << "NamespaceNameSpecifier";
-  case NodeKind::TypeNameSpecifier:
-    return OS << "TypeNameSpecifier";
-  case NodeKind::UnknownNameSpecifier:
-    return OS << "UnknownNameSpecifier";
+  case NodeKind::DecltypeNameSpecifier:
+    return OS << "DecltypeNameSpecifier";
   case NodeKind::IdentifierNameSpecifier:
     return OS << "IdentifierNameSpecifier";
-  case NodeKind::TypeWithTemplateNameSpecifier:
-    return OS << "TypeWithTemplateNameSpecifier";
+  case NodeKind::SimpleTemplateNameSpecifier:
+    return OS << "SimpleTemplateNameSpecifier";
   case NodeKind::NestedNameSpecifier:
     return OS << "NestedNameSpecifier";
   }
diff --git a/clang/unittests/Tooling/Syntax/TreeTest.cpp b/clang/unittests/Tooling/Syntax/TreeTest.cpp
--- a/clang/unittests/Tooling/Syntax/TreeTest.cpp
+++ b/clang/unittests/Tooling/Syntax/TreeTest.cpp
@@ -988,13 +988,13 @@
     | | | |-NestedNameSpecifier
     | | | | |-GlobalNameSpecifier
     | | | | | `-::
-    | | | | |-NamespaceNameSpecifier
+    | | | | |-IdentifierNameSpecifier
     | | | | | |-n
     | | | | | `-::
-    | | | | |-TypeNameSpecifier
+    | | | | |-IdentifierNameSpecifier
     | | | | | |-S
     | | | | | `-::
-    | | | | `-TypeWithTemplateNameSpecifier
+    | | | | `-SimpleTemplateNameSpecifier
     | | | |   |-template
     | | | |   |-TS
     | | | |   |-<
@@ -1010,13 +1010,13 @@
     | |-UnknownExpression
     | | |-IdExpression
     | | | |-NestedNameSpecifier
-    | | | | |-NamespaceNameSpecifier
+    | | | | |-IdentifierNameSpecifier
     | | | | | |-n
     | | | | | `-::
-    | | | | |-TypeNameSpecifier
+    | | | | |-IdentifierNameSpecifier
     | | | | | |-S
     | | | | | `-::
-    | | | | `-TypeNameSpecifier
+    | | | | `-SimpleTemplateNameSpecifier
     | | | |   |-TS
     | | | |   |-<
     | | | |   |-int
@@ -1031,13 +1031,13 @@
     | |-UnknownExpression
     | | |-IdExpression
     | | | |-NestedNameSpecifier
-    | | | | |-TypeNameSpecifier
+    | | | | |-SimpleTemplateNameSpecifier
     | | | | | |-TS
     | | | | | |-<
     | | | | | |-int
     | | | | | |->
     | | | | | `-::
-    | | | | `-TypeNameSpecifier
+    | | | | `-IdentifierNameSpecifier
     | | | |   |-S
     | | | |   `-::
     | | | `-UnqualifiedId
@@ -1052,13 +1052,13 @@
     | |-UnknownExpression
     | | |-IdExpression
     | | | |-NestedNameSpecifier
-    | | | | |-TypeNameSpecifier
+    | | | | |-SimpleTemplateNameSpecifier
     | | | | | |-TS
     | | | | | |-<
     | | | | | |-int
     | | | | | |->
     | | | | | `-::
-    | | | | `-TypeNameSpecifier
+    | | | | `-IdentifierNameSpecifier
     | | | |   |-S
     | | | |   `-::
     | | | |-template
@@ -1116,10 +1116,10 @@
       | |-UnknownExpression
       | | |-IdExpression
       | | | |-NestedNameSpecifier
-      | | | | |-TypeNameSpecifier
+      | | | | |-IdentifierNameSpecifier
       | | | | | |-T
       | | | | | `-::
-      | | | | `-TypeWithTemplateNameSpecifier
+      | | | | `-SimpleTemplateNameSpecifier
       | | | |   |-template
       | | | |   |-U
       | | | |   |-<
@@ -1135,7 +1135,7 @@
       | |-UnknownExpression
       | | |-IdExpression
       | | | |-NestedNameSpecifier
-      | | | | |-TypeNameSpecifier
+      | | | | |-IdentifierNameSpecifier
       | | | | | |-T
       | | | | | `-::
       | | | | `-IdentifierNameSpecifier
@@ -1150,7 +1150,7 @@
       | |-UnknownExpression
       | | |-IdExpression
       | | | |-NestedNameSpecifier
-      | | | | `-TypeNameSpecifier
+      | | | | `-IdentifierNameSpecifier
       | | | |   |-T
       | | | |   `-::
       | | | |-template
@@ -1217,7 +1217,7 @@
     | |-UnknownExpression
     | | |-IdExpression
     | | | |-NestedNameSpecifier
-    | | | | `-TypeNameSpecifier
+    | | | | `-DecltypeNameSpecifier
     | | | |   |-decltype
     | | | |   |-(
     | | | |   |-IdExpression