mirror of https://github.com/rust-lang/rust
36 lines
1.6 KiB
Plaintext
36 lines
1.6 KiB
Plaintext
LL| |#![feature(coroutines, coroutine_trait, stmt_expr_attributes)]
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LL| |
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LL| |use std::ops::{Coroutine, CoroutineState};
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LL| |use std::pin::Pin;
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LL| |
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LL| |// The following implementation of a function called from a `yield` statement
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LL| |// (apparently requiring the Result and the `String` type or constructor)
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LL| |// creates conditions where the `coroutine::StateTransform` MIR transform will
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LL| |// drop all `Counter` `Coverage` statements from a MIR. `simplify.rs` has logic
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LL| |// to handle this condition, and still report dead block coverage.
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LL| 1|fn get_u32(val: bool) -> Result<u32, String> {
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LL| 1| if val {
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LL| 1| Ok(1)
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LL| | } else {
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LL| 0| Err(String::from("some error"))
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LL| | }
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LL| 1|}
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LL| |
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LL| 1|fn main() {
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LL| 1| let is_true = std::env::args().len() == 1;
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LL| 1| let mut coroutine = #[coroutine] || {
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LL| 1| yield get_u32(is_true);
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LL| 1| return "foo";
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LL| 1| };
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LL| |
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LL| 1| match Pin::new(&mut coroutine).resume(()) {
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LL| 1| CoroutineState::Yielded(Ok(1)) => {}
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LL| 0| _ => panic!("unexpected return from resume"),
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LL| | }
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LL| 1| match Pin::new(&mut coroutine).resume(()) {
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LL| 1| CoroutineState::Complete("foo") => {}
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LL| 0| _ => panic!("unexpected return from resume"),
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LL| | }
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LL| 1|}
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