rustc(E0515) when trying to use icmp_packet_iter.next()

[zarkdav]

Apologies if this is a Rust noob question.

I am trying to return the first reply packet from a Layer4(Ipv4(IpNextHeaderProtocols::Icmp)) transport_channel.

The end of my function is:

    let mut rx_iter = icmp_packet_iter(&mut rx);
    rx_iter.next()

And I get the following errors:

error[E0515]: cannot return reference to local variable `rx_iter`
  --> src\main.rs:29:5
   |
29 |     rx_iter.next()
   |     ^^^^^^^^^^^^^^ returns a reference to data owned by the current function

error[E0515]: cannot return value referencing local variable `rx`
  --> src\main.rs:29:5
   |
28 |     let mut rx_iter = icmp_packet_iter(&mut rx);
   |                                        ------- `rx` is borrowed here
29 |     rx_iter.next()
   |     ^^^^^^^^^^^^^^ returns a value referencing data owned by the current function

The official advice is to "consider returning an owned value instead". How should I do it?

[zarkdav]

I tried an std::mem::replace trick without success.

[zarkdav]

I think I found a solution by replacing rx_iter.next() with:

    let reply_packet = rx_iter.next();
    match reply_packet {
        Ok((p, a)) => Ok((IcmpPacket::owned(p.packet().to_vec()).unwrap(), a)),
        Err(e) => Err(e)
    }