}
public static void Main()
{
+ int? w = null;
int? x = null;
int? y = 0;
+ int? z = 1;
+
f (false, x == 0);
f (true, x != 0);
f (false, x == y);
f (true, x != y);
+ f (true, x == w);
+ f (false, x != w);
f (true, x == null);
f (false, x != null);
f (true, 0 == y);
f (false, 0 != y);
+ f (false, z == y);
+ f (true, z != y);
f (false, null == y);
f (true, null != y);
}