Mysterious runtime failures when chaining methods on a Timer

[dmanescu]

In timer.rs:

use std::io::timer::Timer;

fn main(){
    let wait: Receiver<()> = Timer::new().unwrap().oneshot(5000);
    wait.recv();
}

Result:

task '<main>' failed at 'Box<Any>', /path/to/rust/src/libstd/comm/mod.rs:763

Unchaining the oneshot method call results in normal behaviour.

[huonw]

I see:

task '<main>' failed at 'receiving on a closed channel', /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/libstd/comm/mod.rs:763

This isn't really a bug in my mind, but it is quite surprising and it would be nice if there was some way to assist programmers by indicating that chaining directly onto a Timer doesn't do what you expect/want (specifically, the Timer object is dropped at the end of the statement, which destroys the other end of the channel, meaning recv will always fail).

[alexcrichton]

This is indeed expected, and documented, but I am surprised that the error message you are seeing is Box<Any> as opposed to receiving on a closed channel. Can you describe how you compiled this code and how you compiled the compiler?

[dmanescu]

I am using luqman's most recent build for arm-linux-androideabi. I am just compiling with rustc timer.rs && ./timer.
I'm not sure if it's relevant but I am using a rather dodgy cc called by rust to link the executable (my toolchain is GCC 4.4.0 - i.e. extremely old - but this causes linker errors due to missing symbols in libgcc, which I fixed by pasting in libgcc.a and libgcc_eh.a from a 4.6.0 toolchain).