In file included from fields_illegal_tracing.cpp:5: ./fields_illegal_tracing.h:32:1: warning: [blink-gc] Class 'PartObject' contains invalid fields. class PartObject { ^ ./fields_illegal_tracing.h:37:5: note: [blink-gc] OwnPtr field 'm_obj1' to a GC managed class declared here: OwnPtr m_obj1; ^ ./fields_illegal_tracing.h:38:5: note: [blink-gc] RefPtr field 'm_obj2' to a GC managed class declared here: RefPtr m_obj2; ^ ./fields_illegal_tracing.h:40:5: note: [blink-gc] std::unique_ptr field 'm_obj4' to a GC managed class declared here: std::unique_ptr m_obj4; ^ ./fields_illegal_tracing.h:43:1: warning: [blink-gc] Class 'HeapObject' contains invalid fields. class HeapObject : public GarbageCollectedFinalized { ^ ./fields_illegal_tracing.h:48:5: note: [blink-gc] OwnPtr field 'm_obj1' to a GC managed class declared here: OwnPtr m_obj1; ^ ./fields_illegal_tracing.h:49:5: note: [blink-gc] RefPtr field 'm_obj2' to a GC managed class declared here: RefPtr m_obj2; ^ ./fields_illegal_tracing.h:51:5: note: [blink-gc] std::unique_ptr field 'm_obj4' to a GC managed class declared here: std::unique_ptr m_obj4; ^ fields_illegal_tracing.cpp:9:1: warning: [blink-gc] Class 'PartObject' has untraced or not traceable fields. void PartObject::trace(Visitor* visitor) { ^ ./fields_illegal_tracing.h:37:5: note: [blink-gc] Untraceable field 'm_obj1' declared here: OwnPtr m_obj1; ^ ./fields_illegal_tracing.h:38:5: note: [blink-gc] Untraceable field 'm_obj2' declared here: RefPtr m_obj2; ^ ./fields_illegal_tracing.h:40:5: note: [blink-gc] Untraceable field 'm_obj4' declared here: std::unique_ptr m_obj4; ^ fields_illegal_tracing.cpp:16:1: warning: [blink-gc] Class 'HeapObject' has untraced or not traceable fields. void HeapObject::trace(Visitor* visitor) { ^ ./fields_illegal_tracing.h:48:5: note: [blink-gc] Untraceable field 'm_obj1' declared here: OwnPtr m_obj1; ^ ./fields_illegal_tracing.h:49:5: note: [blink-gc] Untraceable field 'm_obj2' declared here: RefPtr m_obj2; ^ ./fields_illegal_tracing.h:51:5: note: [blink-gc] Untraceable field 'm_obj4' declared here: std::unique_ptr m_obj4; ^ 4 warnings generated.