This is xnu-11215.1.10. See this file in: 
//
// Tests for
//  template <typename T, typename U, typename R>
//  bool operator==(intrusive_shared_ptr<T, R> const& x, intrusive_shared_ptr<U, R> const& y);
//
//  template <typename T, typename U, typename R>
//  bool operator!=(intrusive_shared_ptr<T, R> const& x, intrusive_shared_ptr<U, R> const& y);
//

#include <libkern/c++/intrusive_shared_ptr.h>
#include <darwintest.h>
#include "test_policy.h"

struct Base { int i; };
struct Derived : Base { };

struct T { int i; };

template <typename T, typename U>
static void
check_eq(T t, U u)
{
	CHECK(t == u);
	CHECK(u == t);
	CHECK(!(t != u));
	CHECK(!(u != t));
}

template <typename T, typename U>
static void
check_ne(T t, U u)
{
	CHECK(!(t == u));
	CHECK(!(u == t));
	CHECK(t != u);
	CHECK(u != t);
}

template <typename T, typename TQual>
static void
tests()
{
	T obj1{1};
	T obj2{2};

	{
		test_shared_ptr<TQual> const a(&obj1, libkern::no_retain);
		test_shared_ptr<TQual> const b(&obj2, libkern::no_retain);
		check_ne(a, b);
	}

	{
		test_shared_ptr<TQual> const a(&obj1, libkern::no_retain);
		test_shared_ptr<TQual> const b(&obj1, libkern::no_retain);
		check_eq(a, b);
	}

	{
		test_shared_ptr<TQual> const a = nullptr;
		test_shared_ptr<TQual> const b(&obj2, libkern::no_retain);
		check_ne(a, b);
	}

	{
		test_shared_ptr<TQual> const a = nullptr;
		test_shared_ptr<TQual> const b = nullptr;
		check_eq(a, b);
	}
}

template <typename T, typename RelatedT>
static void
tests_convert()
{
	T obj{1};
	test_shared_ptr<T> const a(&obj, libkern::no_retain);
	test_shared_ptr<RelatedT> const b(&obj, libkern::no_retain);
	check_eq(a, b);
}

T_DECL(compare_equal, "intrusive_shared_ptr.compare.equal", T_META_TAG_VM_PREFERRED) {
	tests<T, T>();
	tests<T, T const>();
	tests_convert<Derived, Base>();
	tests_convert<Derived, Base const>();
}