pipes::send_one and pipes::recv_one (and related functions) throw this error: copying a non-copyable variable.
This is the minimum code to reproduce it:
let (chan, port) = pipes::oneshot();
pipes::send_one(chan, true);
That will fail on the second line.
This is actually a big problem, since core::comm is deprecated I don't really have another way to do this kind of communication.