| #![feature(generators, generator_trait)] |
| |
| use std::ops::{Generator, GeneratorState}; |
| use std::pin::Pin; |
| |
| // The following implementation of a function called from a `yield` statement |
| // (apparently requiring the Result and the `String` type or constructor) |
| // creates conditions where the `generator::StateTransform` MIR transform will |
| // drop all `Counter` `Coverage` statements from a MIR. `simplify.rs` has logic |
| // to handle this condition, and still report dead block coverage. |
| fn get_u32(val: bool) -> Result<u32, String> { |
| if val { Ok(1) } else { Err(String::from("some error")) } |
| } |
| |
| fn main() { |
| let is_true = std::env::args().len() == 1; |
| let mut generator = || { |
| yield get_u32(is_true); |
| return "foo"; |
| }; |
| |
| match Pin::new(&mut generator).resume(()) { |
| GeneratorState::Yielded(Ok(1)) => {} |
| _ => panic!("unexpected return from resume"), |
| } |
| match Pin::new(&mut generator).resume(()) { |
| GeneratorState::Complete("foo") => {} |
| _ => panic!("unexpected return from resume"), |
| } |
| } |