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