diff --git a/include/v8-forward.h b/include/v8-forward.h
index 91b1ea0340..db3a2017b7 100644
--- a/include/v8-forward.h
+++ b/include/v8-forward.h
@@ -27,6 +27,7 @@ class Context;
 class DataView;
 class Data;
 class Date;
+class Extension;
 class External;
 class FixedArray;
 class Float32Array;
@@ -63,6 +64,7 @@ class StringObject;
 class Symbol;
 class SymbolObject;
 class Template;
+class TryCatch;
 class TypedArray;
 class Uint16Array;
 class Uint32;