E.g. from here:
https://ci.chromium.org/buildbot/chromium.clang/ToTLinux/4557
Note that the line number mixin_marker.cpp:47 has changed to 48 with the new clang, which seems incorrect.


Testing missing_mixin_marker.cpp... failed: expected and actual differed
Actual:
missing_mixin_marker.cpp:15:58: warning: [blink-gc] Garbage-collected class 'Derived' derives mixin class 'Mixin'. You must add USING_GARBAGE_COLLECTED_MIXIN(Derived).
class Derived : public GarbageCollected<Derived>, public Mixin {
                                                  ~~~~~~~^~~~~
missing_mixin_marker.cpp:9:22: note: [blink-gc] Mixin base class derived here:
class Mixin : public GarbageCollectedMixin {
              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:27:29: warning: [blink-gc] Garbage-collected class 'MySupplement' derives mixin class 'Supplement<blink::Derived>'. You must add USING_GARBAGE_COLLECTED_MIXIN(MySupplement).
                     public Supplement<Derived> {
                     ~~~~~~~^~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:20:27: note: [blink-gc] Mixin base class derived here:
class Supplement : public GarbageCollectedMixin {
                   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:53:35: warning: [blink-gc] Garbage-collected class 'PureVirtualDerived' derives mixin class 'Mixin'. You must add USING_GARBAGE_COLLECTED_MIXIN(PureVirtualDerived).
class PureVirtualDerived : public PureVirtual {
                           ~~~~~~~^~~~~~~~~~~
missing_mixin_marker.cpp:48:66: note: [blink-gc] Mixin base class derived here:
class PureVirtual : public GarbageCollected<PureVirtual>, public Mixin {
                                                          ~~~~~~~^~~~~
missing_mixin_marker.cpp:9:22: note: [blink-gc] Mixin base class derived here:
class Mixin : public GarbageCollectedMixin {
              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
3 warnings generated.
Expected:
missing_mixin_marker.cpp:15:58: warning: [blink-gc] Garbage-collected class 'Derived' derives mixin class 'Mixin'. You must add USING_GARBAGE_COLLECTED_MIXIN(Derived).
class Derived : public GarbageCollected<Derived>, public Mixin {
                                                  ~~~~~~~^~~~~
missing_mixin_marker.cpp:9:22: note: [blink-gc] Mixin base class derived here:
class Mixin : public GarbageCollectedMixin {
              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:27:29: warning: [blink-gc] Garbage-collected class 'MySupplement' derives mixin class 'Supplement<blink::Derived>'. You must add USING_GARBAGE_COLLECTED_MIXIN(MySupplement).
                     public Supplement<Derived> {
                     ~~~~~~~^~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:20:27: note: [blink-gc] Mixin base class derived here:
class Supplement : public GarbageCollectedMixin {
                   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
missing_mixin_marker.cpp:52:35: warning: [blink-gc] Garbage-collected class 'PureVirtualDerived' derives mixin class 'Mixin'. You must add USING_GARBAGE_COLLECTED_MIXIN(PureVirtualDerived).
class PureVirtualDerived : public PureVirtual {
                           ~~~~~~~^~~~~~~~~~~
missing_mixin_marker.cpp:47:66: note: [blink-gc] Mixin base class derived here:
class PureVirtual : public GarbageCollected<PureVirtual>, public Mixin {
                                                          ~~~~~~~^~~~~
missing_mixin_marker.cpp:9:22: note: [blink-gc] Mixin base class derived here:
class Mixin : public GarbageCollectedMixin {
              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
3 warnings generated.