In file included from stack_allocated.cpp:5:
./stack_allocated.h:14:1: warning: [blink-gc] Class 'PartObject' requires a trace method.
class PartObject {
^
./stack_allocated.h:17:5: note: [blink-gc] Untraced field 'm_obj' declared here:
    Member<HeapObject> m_obj; // Needs tracing.
    ^
./stack_allocated.h:24:5: warning: [blink-gc] The stack allocated class 'StackObject' provides an unnecessary trace method:
    void Trace(Visitor* visitor) const { visitor->Trace(m_obj); }
    ^
./stack_allocated.h:30:1: warning: [blink-gc] Class 'HeapObject' contains invalid fields.
class HeapObject : public GarbageCollected<HeapObject> {
^
./stack_allocated.h:35:5: note: [blink-gc] Stack-allocated field 'm_part' declared here:
    StackObject m_part; // Cannot embed a stack allocated object.
    ^
./stack_allocated.h:39:27: warning: [blink-gc] Stack-allocated class 'DerivedHeapObject' derives class 'HeapObject' which is garbage collected.
class DerivedHeapObject : public HeapObject, public StackObject {
                          ^
./stack_allocated.h:43:28: warning: [blink-gc] Stack-allocated class 'DerivedHeapObject2' derives class 'HeapObject' which is garbage collected.
class DerivedHeapObject2 : public HeapObject {
                           ^
./stack_allocated.h:24:5: warning: [blink-gc] Class 'StackObject' has untraced or not traceable fields.
    void Trace(Visitor* visitor) const { visitor->Trace(m_obj); }
    ^
./stack_allocated.h:27:5: note: [blink-gc] Untraceable field 'm_obj' declared here:
    HeapObject* m_obj; // Does not need tracing.
    ^
6 warnings generated.