message: Simplify Handle's Clone impl.
diff: @@ -24,7 +24,7 @@ pub struct Handle<'handle, L: List> {
  // those constraints, so we manually implement Clone and Copy.
  impl<'handle, L: List> Clone for Handle<'handle, L> {
  fn clone(&self) -> Self {
  - Handle { _list: PhantomData }
  + *self
  }
  }
  