[rust-dev] possible code dump bug (state machine iterator)

[Phil Dawes]

Hello everyone,

I was trying to create an iterator that used a function pointer to
alternate between different states, and ended up core dumping. I've pasted
a version that generates the issue on my box (Ubuntu 12.04 LTS,
rust-nightly pulled just now). Can anybody reproduce this on their
machines? If so I'll file a bug.

Cheers,

Phil

struct StateMachineIter<'a> {
    statefn: &'a fn(&mut StateMachineIter<'a>) -> Option<&'static str>
}

impl<'a> Iterator<&'static str> for StateMachineIter<'a> {
    fn next(&mut self) -> Option<&'static str> {
        return  (*self.statefn)(self);
    }
}

fn state1(self_: &mut StateMachineIter) -> Option<&'static str> {
    self_.statefn = &state2;
    return Some("state1");
}

fn state2(self_: &mut StateMachineIter) -> Option<(&'static str)> {
    self_.statefn = &state3;
    return Some("state2");
}

fn state3(self_: &mut StateMachineIter) -> Option<(&'static str)> {
    self_.statefn = &finished;
    return Some("state3");
}

fn finished(_: &mut StateMachineIter) -> Option<(&'static str)> {
    return None;
}

fn state_iter() -> StateMachineIter {
    StateMachineIter { statefn: &state1 }
}


fn main() {
    let mut it = state_iter();
    println!("{}",it.next());
    println!("{}",it.next());
    println!("{}",it.next());
    println!("{}",it.next());
    println!("{}",it.next());
}

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