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Use ? in prepare_vtable_segments

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This commit is contained in:
Maybe Waffle 2023-07-19 09:45:26 +00:00
parent eabd306265
commit 348f26e409
1 changed files with 15 additions and 9 deletions
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24
compiler/rustc_trait_selection/src/traits/vtable.rs
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@ -24,8 +24,18 @@ pub enum VtblSegment<'tcx> {
pub fn prepare_vtable_segments<'tcx, T>(
tcx: TyCtxt<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
mut segment_visitor: impl FnMut(VtblSegment<'tcx>) -> ControlFlow<T>,
segment_visitor: impl FnMut(VtblSegment<'tcx>) -> ControlFlow<T>,
) -> Option<T> {
prepare_vtable_segments_inner(tcx, trait_ref, segment_visitor).break_value()
}
/// Helper for [`prepare_vtable_segments`] that returns `ControlFlow`,
/// such that we can use `?` in the body.
fn prepare_vtable_segments_inner<'tcx, T>(
tcx: TyCtxt<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
mut segment_visitor: impl FnMut(VtblSegment<'tcx>) -> ControlFlow<T>,
) -> ControlFlow<T> {
// The following constraints holds for the final arrangement.
// 1. The whole virtual table of the first direct super trait is included as the
// the prefix. If this trait doesn't have any super traits, then this step
@ -71,9 +81,7 @@ pub fn prepare_vtable_segments<'tcx, T>(
// N, N-vptr, O
// emit dsa segment first.
if let ControlFlow::Break(v) = (segment_visitor)(VtblSegment::MetadataDSA) {
return Some(v);
}
segment_visitor(VtblSegment::MetadataDSA)?;
let mut emit_vptr_on_new_entry = false;
let mut visited = PredicateSet::new(tcx);
@ -146,12 +154,10 @@ pub fn prepare_vtable_segments<'tcx, T>(
// emit innermost item, move to next sibling and stop there if possible, otherwise jump to outer level.
'exiting_out: loop {
if let Some((inner_most_trait_ref, emit_vptr, siblings_opt)) = stack.last_mut() {
if let ControlFlow::Break(v) = (segment_visitor)(VtblSegment::TraitOwnEntries {
segment_visitor(VtblSegment::TraitOwnEntries {
trait_ref: *inner_most_trait_ref,
emit_vptr: *emit_vptr,
}) {
return Some(v);
}
})?;
'exiting_out_skip_visited_traits: loop {
if let Some(siblings) = siblings_opt {
@ -174,7 +180,7 @@ pub fn prepare_vtable_segments<'tcx, T>(
}
}
// all done
return None;
return ControlFlow::Continue(());
}
}
}