[BUG] queue transfer to self should be no-op

[quake]

Describe the bug queue transfer to self should be no-op

To Reproduce

fn main {
    let q = @queue.of([1, 2, 3])
    q.transfer(q)
    println(q)
}

ouputs @queue.of([])

Expected behavior @queue.of([1, 2, 3])

[peter-jerry-ye]

/// Transfers all elements from one queue to another.
///
/// Adds all of the elements of source to the end of destination, then clears source.

[hackwaly]

This is not intuitive. The implementation detail should not lead API design

[peter-jerry-ye]

It is what it is. Transferring to self doesn't make sense either. With that said, with the append implemented, I would rather deprecate this API.

[hackwaly]

However, append will not imply the empty operation on source.

[peter-jerry-ye]

Yes, and it is exactly this empty operation is bizarre when the source and dst refers to the same one