RustのDrop traitの確認

コード：

struct DropTest {
  id: u32,
}

impl DropTest {
  fn create(id: u32) -> DropTest {
     DropTest { id: id }
  }
}

impl Drop for DropTest {
  fn drop(&mut self) {
     println!("Dropping {}...", self.id);
  }
}

fn sample_func(_: &DropTest, _: &DropTest) {
   println!("sample_func");
}

fn main() {
  println!("Start main");
  {
     println!("Start block");
     let d = DropTest::create(1);
     sample_func(&DropTest::create(2), &d);
     println!("End block");
  }
  println!("End main");
}

結果

Start main
Start block
sample_func
Dropping 2...  →呼び終わったらdrop
End block
Dropping 1...  →block終わったのでdrop
End main