--- old/src/hotspot/share/gc/g1/g1YoungGenSizer.hpp	2020-01-03 17:56:51.154842344 +0800
+++ new/src/hotspot/share/gc/g1/g1YoungGenSizer.hpp	2020-01-03 17:56:51.156842416 +0800
@@ -63,7 +63,12 @@
 //
 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
+
+// Forward declarations
+class G1HeapSizingPolicy;
+
 class G1YoungGenSizer : public CHeapObj<mtGC> {
+  friend class G1HeapSizingPolicy;
 private:
   enum SizerKind {
     SizerDefaults,