~= call copy ctor?

[Namespace]

Ok, so if a put a struct into an array, it will copied into the 
array. But then? How it is deleted?

For exmaple, i have this code:

[code]
import std.stdio;

struct Test {
public:
	static uint _counter;

	this(int i = 0) {
		writeln("Test CTor.");

		_counter++;
	}

	this(this) {
		writeln("Test Copy CTor");

		_counter++;
	}

	~this() {
		writeln("Test DTor");

		if (_counter > 0) {
			_counter--;
		}
	}
}

void main() {
	{
		Test[] _arr;

		void copy_save(Test t) {
			_arr ~= t;
		}

		void by_ref_save(ref Test t) {
			_arr ~= t;
		}

		Test t = 42;

		//copy_save(t);
		by_ref_save(t);

		writeln("end scope");
	}

	writefln("Counter: %d", Test._counter);
}
[/code]

_counter is still 1 but the scope is released. How is that 
possible?
Even with _arr.clear(); at the end of the scope, _counter is 
still 1.
I see one CTor and one Copy CTor but only one DTor.