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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|}
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