https://github.com/openjdk/loom/blob/fibers/src/hotspot/share/compiler/oopMap.cpp#L476

When derived_mode is default, not in (_directly, _, _with_table, _ignore):
Uninitialised pointer 'derived_cl' may be used as argument 3 when calling OopMapDo<OopClosure, DerivedOopClosure, SkipNullValue>::OopMapDo