| 1| |#![feature(generators, generator_trait)] | |
| 2| | | |
| 3| |use std::ops::{Generator, GeneratorState}; | |
| 4| |use std::pin::Pin; | |
| 5| | | |
| 6| |// The following implementation of a function called from a `yield` statement | |
| 7| |// (apparently requiring the Result and the `String` type or constructor) | |
| 8| |// creates conditions where the `generator::StateTransform` MIR transform will | |
| 9| |// drop all `Counter` `Coverage` statements from a MIR. `simplify.rs` has logic | |
| 10| |// to handle this condition, and still report dead block coverage. | |
| 11| 1|fn get_u32(val: bool) -> Result<u32, String> { | |
| 12| 1| if val { Ok(1) } else { Err(String::from("some error")) } | |
| ^0 | |
| 13| 1|} | |
| 14| | | |
| 15| 1|fn main() { | |
| 16| 1| let is_true = std::env::args().len() == 1; | |
| 17| 1| let mut generator = || { | |
| 18| 1| yield get_u32(is_true); | |
| 19| 1| return "foo"; | |
| 20| 1| }; | |
| 21| | | |
| 22| 1| match Pin::new(&mut generator).resume(()) { | |
| 23| 1| GeneratorState::Yielded(Ok(1)) => {} | |
| 24| 0| _ => panic!("unexpected return from resume"), | |
| 25| | } | |
| 26| 1| match Pin::new(&mut generator).resume(()) { | |
| 27| 1| GeneratorState::Complete("foo") => {} | |
| 28| 0| _ => panic!("unexpected return from resume"), | |
| 29| | } | |
| 30| 1|} | |