diff --git a/clang/include/clang/Tooling/Syntax/Tree.h b/clang/include/clang/Tooling/Syntax/Tree.h
--- a/clang/include/clang/Tooling/Syntax/Tree.h
+++ b/clang/include/clang/Tooling/Syntax/Tree.h
@@ -213,6 +213,7 @@
   };
 
   using Tree::Tree;
+  static bool classof(const Node *N);
   /// Returns the elements and corresponding delimiters. Missing elements
   /// and delimiters are represented as null pointers.
   ///
diff --git a/clang/lib/Tooling/Syntax/Tree.cpp b/clang/lib/Tooling/Syntax/Tree.cpp
--- a/clang/lib/Tooling/Syntax/Tree.cpp
+++ b/clang/lib/Tooling/Syntax/Tree.cpp
@@ -273,6 +273,17 @@
   return nullptr;
 }
 
+bool classof(const syntax::Node *N) {
+  switch (N->getKind()) {
+  case syntax::NodeKind::NestedNameSpecifier:
+  case syntax::NodeKind::CallArguments:
+  case syntax::NodeKind::ParameterDeclarationList:
+    return true;
+  default:
+    return false;
+  }
+}
+
 std::vector<syntax::List::ElementAndDelimiter<syntax::Node>>
 syntax::List::getElementsAsNodesAndDelimiters() {
   if (!getFirstChild())