In file included from ref_ptr_to_gc_managed_class.cpp:5: ./ref_ptr_to_gc_managed_class.h:14:1: warning: [blink-gc] Class 'PartObject' contains invalid fields. class PartObject { ^ ./ref_ptr_to_gc_managed_class.h:17:5: note: [blink-gc] scoped_refptr field 'm_obj' to a GC managed class declared here: scoped_refptr m_obj; ^ ./ref_ptr_to_gc_managed_class.h:20:1: warning: [blink-gc] Class 'HeapObject' contains invalid fields. class HeapObject : public GarbageCollected { ^ ./ref_ptr_to_gc_managed_class.h:26:3: note: [blink-gc] scoped_refptr field 'm_objs' to a GC managed class declared here: Vector> m_objs; ^ 2 warnings generated.