Segfault with simple twiddle objects

[brson]

pub trait EventLoop {
}

pub struct UvEventLoop {
    uvio: int
}

pub impl UvEventLoop {
    static fn new() -> UvEventLoop {
        UvEventLoop {
            uvio: 0
        }
    }
}

impl EventLoop for UvEventLoop {
}

pub struct Scheduler {
    event_loop: ~EventLoop,
}

pub impl Scheduler {

    static fn new(event_loop: ~EventLoop) -> Scheduler {
        Scheduler {
            event_loop: event_loop,
        }
    }
}

fn main() {
    let mut sched = Scheduler::new(~UvEventLoop::new() as ~EventLoop);
}

Blocks #4419

[graydon]

possibly addressed by #5597 ? not sure

[graydon]

assigning bug; change assignment if you disagree

[catamorphism]

This seems to be fixed. I'll check in the test case.