I'm just getting my head round this whole DI thing, but something seems to be happening that I wonder shouldn't.

If I register a class in my AppServiceProvider, then inject it into a controller method, I can seemingly also App::make() it for the second time:

// class
class Foo
{
	public function __construct()
	{
		pr('ECHO!');
	}
}

// app service provider
$this->app->singleton('Foo', function () {
	return new Foo();
});

// controller
public function view(Foo $foo) // will call
{
    \App::make('Foo'); // will call
    \App::make('Foo'); // won't call
}

ECHO!
ECHO!

What's going on? Is the container not supposed to resolve this singleton only once?