Calling `unwrap()` on JoinGuard::join() failed

[zonyitoo]

Here is the test case

use std::thread::Thread;
fn main() {
    Thread::spawn(move || {
        println!("Hello");
    }).join().unwrap();
}

and rustc said

t.rs:7:15: 7:23 error: type `core::result::Result<(), Box<core::any::Any + Send>>` does not implement any method in scope named `unwrap`
t.rs:7     }).join().unwrap();
                     ^~~~~~~~
error: aborting due to previous error

rustc rustc 0.13.0-nightly (7e11b2271 2014-12-24 20:47:12 +0000)

Result does not have the unwrap() method anymore?

[bkoropoff]

It does, but it bounds the error type by Show, which Box<Any + Send> does not meet. Ideally the diagnostic would mention this.

[zonyitoo]

@bkoropoff Ok, that's right. Thank you.