This is xnu-8019. See this file in:
Directory listing for xnu-8019//tests/intrusive_shared_ptr_src
abi.callee.raw.cpp
abi.callee.smart.cpp
abi.caller.raw.cpp
abi.caller.smart.cpp
abi.size_alignment.cpp
abi_helper.h
assign.copy.cpp
assign.move.cpp
assign.nullptr.cpp
cast.const.cpp
cast.reinterpret.cpp
cast.static.cpp
compare.equal.cpp
compare.equal.nullptr.cpp
compare.equal.raw.cpp
ctor.copy.cpp
ctor.default.cpp
ctor.move.cpp
ctor.nullptr.cpp
ctor.ptr.no_retain.cpp
ctor.ptr.retain.cpp
deref.cpp
detach.cpp
dtor.cpp
get.cpp
operator.bool.cpp
reset.cpp
reset.no_retain.cpp
reset.retain.cpp
swap.cpp
test_policy.h