core.atomic bug? windows 2008r2 dmd 2.69.2 x64

[sdv via Digitalmars-d]

struct sts
{
	size_t a1;
	struct m1{
		size_t a9;
		size_t a10;
	}
	shared m1	t1;
}

int main(string[] argv)
{

	auto y1 = new sts();
	cas(&y1.t1,y1.t1,y1.t1);

     return 0;
}