| // run-pass |
| #![allow(dead_code)] |
| // This code produces a CFG with critical edges that, if we don't |
| // handle properly, will cause invalid codegen. |
| |
| #![feature(rustc_attrs)] |
| |
| enum State { |
| Both, |
| Front, |
| Back |
| } |
| |
| pub struct Foo<A: Iterator, B: Iterator> { |
| state: State, |
| a: A, |
| b: B |
| } |
| |
| impl<A, B> Foo<A, B> |
| where A: Iterator, B: Iterator<Item=A::Item> |
| { |
| // This is the function we care about |
| fn next(&mut self) -> Option<A::Item> { |
| match self.state { |
| State::Both => match self.a.next() { |
| elt @ Some(..) => elt, |
| None => { |
| self.state = State::Back; |
| self.b.next() |
| } |
| }, |
| State::Front => self.a.next(), |
| State::Back => self.b.next(), |
| } |
| } |
| } |
| |
| // Make sure we actually codegen a version of the function |
| pub fn do_stuff(mut f: Foo<Box<dyn Iterator<Item=u32>>, Box<dyn Iterator<Item=u32>>>) { |
| let _x = f.next(); |
| } |
| |
| fn main() {} |