Iterating over the tupleof of a struct

[Meta via Digitalmars-d-learn]

Something weird happens when I try to foreach over test.tupleof. 
If the foreach loop has 2 variables like so:

struct Test
{
	string name = "'null'";
	int id;
}

void main()
{
	auto test = Test();
	assert(test.name == "'null'");
	assert(test.id == 0);
	
	foreach (val1, val2; test.tupleof)
	{
		import std.stdio, std.conv, std.traits;
		writeln(typeof(val1).stringof, "->", val1, " ",
                         typeof(val2).stringof, "->", val2);
	}
}

The following is printed:

ulong->0 string->'null'
ulong->1 int->0



If the foreach only has 1 variable, like this:

	foreach (val; test.tupleof)
	{
		import std.stdio, std.conv, std.traits;
		writeln(typeof(val).stringof, "->", val);
	}

The following is printed instead:

string->'null'
int->0



What is happening here? Are these two extra ulongs the offsets of 
the fields in the struct?