Thread crashes if Receiver is used

[vhbit]

Here is a test case:

use std::rt::thread::Thread;

fn write_loop(rx: Receiver<uint>) {
    loop {
        match rx.recv_opt() {
            Ok(v) => println!("v {}", v),
            _ => break
        }
    }
}

fn main() {
    let (tx, rx) = channel();
    Thread::start(proc() {
        write_loop(rx);
    });

    tx.send(3u);
}

Output: fatal runtime error: assertion failed: !ptr.is_null()

I guess that's because there is no Task associated with thread and while it is possible to create a task manually - there is no known for me way to put Runtime into it.

Considering there is no direct way to guess what for this thread is created and whether it should use native runtime or not, it is reasonable. But it is still quite unexpected, so I believe there should be either a way to put runtime into it or documentation of Receiver should note that more clearly.

FWIW, there is a way: http://doc.rust-lang.org/rustrt/task/struct.Task.html#method.put_runtime.

[vhbit]

I know about 'put_runtime' but have no idea how to get one to put it

[steveklabnik]

This does not crash today:

use std::thread::Thread;
use std::sync::mpsc::Receiver;
use std::sync::mpsc::channel;

fn write_loop(rx: Receiver<uint>) {
    loop {
        match rx.try_recv() {
            Ok(v) => println!("v {}", v),
            _ => break
        }
    }
}

fn main() {
    let (tx, rx) = channel();
    Thread::scoped(move || {
        write_loop(rx);
    }).join();

    tx.send(3u);
}

Compiles and runs, though it has no output.