Channel select panics "passed a receiver that wasn't selected" when using different clones of the same receiver

[ChocolateLoverRaj]

The correct id gets selected but when I try to do the operation it fails. I think this is a bug because I expect cloning a receiver to still be the same receiver.

Way of reproducing:

use crossbeam_channel::{Select, unbounded};

fn main() {
    let (tx, rx) = unbounded::<u32>();
    tx.send(123).unwrap();
    let mut select = Select::new();
    let id = select.recv(&rx);
    let operation = select.select();
    println!("recv id: {}. selected id: {}.", id, operation.index());
    operation.recv(&rx.clone()).unwrap();
}

[dependencies]
crossbeam-channel = "0.5.12"

[taiki-e]

Currently, we are using a reference to the sender as an identifier, but I guess we can fix this by using the pointer that the sender points to as an identifier.

crossbeam/crossbeam-channel/src/select.rs

Line 645 in 9e85961

let ptr = s as *const Sender<_> as *const u8;

crossbeam/crossbeam-channel/src/counter.rs

Lines 38 to 39 in 9e85961

	pub(crate) struct Sender<C> {
	counter: NonNull<Counter<C>>,

[ChocolateLoverRaj]

Can the bug label be added to this? This is a bug imo.