trace_after_dispatch.cpp:13:1: warning: [blink-gc] Missing dispatch to class 'D' in manual trace dispatch.
void A::Trace(Visitor* visitor) const {
^
In file included from trace_after_dispatch.cpp:5:
./trace_after_dispatch.h:61:3: warning: [blink-gc] Class 'E' inherits from a hierarchy that uses TraceAfterDispatch to dispatch tracing. Only the hierarchy base class 'A' should declare a Trace method. Remove the extra Trace method:
  void Trace(Visitor*) const;
  ^
trace_after_dispatch.cpp:32:1: warning: [blink-gc] Base class 'A' of derived class 'B' requires tracing.
void B::TraceAfterDispatch(Visitor* visitor) const {
^
trace_after_dispatch.cpp:39:1: warning: [blink-gc] Class 'C' has untraced fields that require tracing.
void C::TraceAfterDispatch(Visitor* visitor) const {
^
./trace_after_dispatch.h:40:5: note: [blink-gc] Untraced field 'm_a' declared here:
    Member<A> m_a;
    ^
4 warnings generated.