diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index de6800deb0..38277e9557 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -764,6 +764,7 @@ class HValue: public ZoneObject {
   int flags_;
   GVNFlagSet gvn_flags_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(HValue);
 };