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Error on using yield without also using #[coroutine] on the closure

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And suggest adding the `#[coroutine]` to the closure
This commit is contained in:
Oli Scherer 2024-04-11 13:15:34 +00:00
parent a589632dad
commit aef0f4024a
279 changed files with 1290 additions and 886 deletions
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78
compiler/rustc_middle/src/ty/closure.rs
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@ -422,49 +422,53 @@ pub fn analyze_coroutine_closure_captures<'a, 'tcx: 'a, T>(
child_captures: impl IntoIterator<Item = &'a CapturedPlace<'tcx>>,
mut for_each: impl FnMut((usize, &'a CapturedPlace<'tcx>), (usize, &'a CapturedPlace<'tcx>)) -> T,
) -> impl Iterator<Item = T> + Captures<'a> + Captures<'tcx> {
std::iter::from_coroutine(move || {
let mut child_captures = child_captures.into_iter().enumerate().peekable();
std::iter::from_coroutine(
#[cfg_attr(not(bootstrap), coroutine)]
move || {
let mut child_captures = child_captures.into_iter().enumerate().peekable();
// One parent capture may correspond to several child captures if we end up
// refining the set of captures via edition-2021 precise captures. We want to
// match up any number of child captures with one parent capture, so we keep
// peeking off this `Peekable` until the child doesn't match anymore.
for (parent_field_idx, parent_capture) in parent_captures.into_iter().enumerate() {
// Make sure we use every field at least once, b/c why are we capturing something
// if it's not used in the inner coroutine.
let mut field_used_at_least_once = false;
// One parent capture may correspond to several child captures if we end up
// refining the set of captures via edition-2021 precise captures. We want to
// match up any number of child captures with one parent capture, so we keep
// peeking off this `Peekable` until the child doesn't match anymore.
for (parent_field_idx, parent_capture) in parent_captures.into_iter().enumerate() {
// Make sure we use every field at least once, b/c why are we capturing something
// if it's not used in the inner coroutine.
let mut field_used_at_least_once = false;
// A parent matches a child if they share the same prefix of projections.
// The child may have more, if it is capturing sub-fields out of
// something that is captured by-move in the parent closure.
while child_captures.peek().map_or(false, |(_, child_capture)| {
child_prefix_matches_parent_projections(parent_capture, child_capture)
}) {
let (child_field_idx, child_capture) = child_captures.next().unwrap();
// This analysis only makes sense if the parent capture is a
// prefix of the child capture.
assert!(
child_capture.place.projections.len() >= parent_capture.place.projections.len(),
"parent capture ({parent_capture:#?}) expected to be prefix of \
// A parent matches a child if they share the same prefix of projections.
// The child may have more, if it is capturing sub-fields out of
// something that is captured by-move in the parent closure.
while child_captures.peek().map_or(false, |(_, child_capture)| {
child_prefix_matches_parent_projections(parent_capture, child_capture)
}) {
let (child_field_idx, child_capture) = child_captures.next().unwrap();
// This analysis only makes sense if the parent capture is a
// prefix of the child capture.
assert!(
child_capture.place.projections.len()
>= parent_capture.place.projections.len(),
"parent capture ({parent_capture:#?}) expected to be prefix of \
child capture ({child_capture:#?})"
);
);
yield for_each(
(parent_field_idx, parent_capture),
(child_field_idx, child_capture),
);
yield for_each(
(parent_field_idx, parent_capture),
(child_field_idx, child_capture),
);
field_used_at_least_once = true;
field_used_at_least_once = true;
}
// Make sure the field was used at least once.
assert!(
field_used_at_least_once,
"we captured {parent_capture:#?} but it was not used in the child coroutine?"
);
}
// Make sure the field was used at least once.
assert!(
field_used_at_least_once,
"we captured {parent_capture:#?} but it was not used in the child coroutine?"
);
}
assert_eq!(child_captures.next(), None, "leftover child captures?");
})
assert_eq!(child_captures.next(), None, "leftover child captures?");
},
)
}
fn child_prefix_matches_parent_projections(