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fn id<T>(x: T) -> T { x }
struct StateMachineIter<'a> {
statefn: &'a StateMachineFunc<'a>
}
type StateMachineFunc<'a> = fn(&mut StateMachineIter<'a>) -> Option<&'static str>;
impl<'a> Iterator for StateMachineIter<'a> {
type Item = &'static str;
fn next(&mut self) -> Option<&'static str> {
return (*self.statefn)(self);
}
}
fn state1(self_: &mut StateMachineIter) -> Option<&'static str> {
self_.statefn = &id(state2 as StateMachineFunc);
//~^ ERROR temporary value dropped while borrowed
return Some("state1");
}
fn state2(self_: &mut StateMachineIter) -> Option<(&'static str)> {
self_.statefn = &id(state3 as StateMachineFunc);
//~^ ERROR temporary value dropped while borrowed
return Some("state2");
}
fn state3(self_: &mut StateMachineIter) -> Option<(&'static str)> {
self_.statefn = &id(finished as StateMachineFunc);
//~^ ERROR temporary value dropped while borrowed
return Some("state3");
}
fn finished(_: &mut StateMachineIter) -> Option<(&'static str)> {
return None;
}
fn state_iter() -> StateMachineIter<'static> {
StateMachineIter {
//~^ ERROR cannot return value referencing temporary value
statefn: &id(state1 as StateMachineFunc)
}
}
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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