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mir borrowck: cleanup late-bound region handling

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This commit is contained in:
lcnr 2025-01-14 11:58:42 +01:00
parent e491caec14
commit 99657aa338
7 changed files with 33 additions and 47 deletions
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1
compiler/rustc_borrowck/src/renumber.rs
View file

@ -34,7 +34,6 @@ pub(crate) enum RegionCtxt {
Location(Location),
TyContext(TyContext),
Free(Symbol),
Bound(Symbol),
LateBound(Symbol),
Existential(Option<Symbol>),
Placeholder(Symbol),

63
compiler/rustc_borrowck/src/universal_regions.rs
View file

@ -467,15 +467,13 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
self.infcx.tcx.local_parent(self.mir_def),
|r| {
debug!(?r);
if !indices.indices.contains_key(&r) {
let region_vid = {
let name = r.get_name_or_anon();
self.infcx.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
};
let region_vid = {
let name = r.get_name_or_anon();
self.infcx.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
};
debug!(?region_vid);
indices.insert_late_bound_region(r, region_vid.as_var());
}
debug!(?region_vid);
indices.insert_late_bound_region(r, region_vid.as_var());
},
);
@ -484,21 +482,17 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
self.infcx.num_region_vars()
};
// "Liberate" the late-bound regions. These correspond to
// "local" free regions.
// Converse of above, if this is a function/closure then the late-bound regions declared
// on its signature are local.
//
// We manually loop over `bound_inputs_and_output` instead of using
// `for_each_late_bound_region_in_item` as we may need to add the otherwise
// implicit `ClosureEnv` region.
let bound_inputs_and_output = self.compute_inputs_and_output(&indices, defining_ty);
let inputs_and_output = self.infcx.replace_bound_regions_with_nll_infer_vars(
FR,
self.mir_def,
bound_inputs_and_output,
&mut indices,
);
// Converse of above, if this is a function/closure then the late-bound regions declared on its
// signature are local.
for_each_late_bound_region_in_item(self.infcx.tcx, self.mir_def, |r| {
debug!(?r);
if !indices.indices.contains_key(&r) {
for (idx, bound_var) in bound_inputs_and_output.bound_vars().iter().enumerate() {
if let ty::BoundVariableKind::Region(kind) = bound_var {
let kind = ty::LateParamRegionKind::from_bound(ty::BoundVar::from_usize(idx), kind);
let r = ty::Region::new_late_param(self.infcx.tcx, self.mir_def.to_def_id(), kind);
let region_vid = {
let name = r.get_name_or_anon();
self.infcx.next_nll_region_var(FR, || RegionCtxt::LateBound(name))
@ -507,7 +501,12 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
debug!(?region_vid);
indices.insert_late_bound_region(r, region_vid.as_var());
}
});
}
let inputs_and_output = self.infcx.replace_bound_regions_with_nll_infer_vars(
self.mir_def,
bound_inputs_and_output,
&indices,
);
let (unnormalized_output_ty, mut unnormalized_input_tys) =
inputs_and_output.split_last().unwrap();
@ -832,10 +831,9 @@ impl<'tcx> BorrowckInferCtxt<'tcx> {
#[instrument(level = "debug", skip(self, indices))]
fn replace_bound_regions_with_nll_infer_vars<T>(
&self,
origin: NllRegionVariableOrigin,
all_outlive_scope: LocalDefId,
value: ty::Binder<'tcx, T>,
indices: &mut UniversalRegionIndices<'tcx>,
indices: &UniversalRegionIndices<'tcx>,
) -> T
where
T: TypeFoldable<TyCtxt<'tcx>>,
@ -845,18 +843,7 @@ impl<'tcx> BorrowckInferCtxt<'tcx> {
let kind = ty::LateParamRegionKind::from_bound(br.var, br.kind);
let liberated_region =
ty::Region::new_late_param(self.tcx, all_outlive_scope.to_def_id(), kind);
let region_vid = {
let name = match br.kind.get_name() {
Some(name) => name,
_ => sym::anon,
};
self.next_nll_region_var(origin, || RegionCtxt::Bound(name))
};
indices.insert_late_bound_region(liberated_region, region_vid.as_var());
debug!(?liberated_region, ?region_vid);
region_vid
ty::Region::new_var(self.tcx, indices.to_region_vid(liberated_region))
});
value
}
@ -870,7 +857,7 @@ impl<'tcx> UniversalRegionIndices<'tcx> {
/// well. These are used for error reporting.
fn insert_late_bound_region(&mut self, r: ty::Region<'tcx>, vid: ty::RegionVid) {
debug!("insert_late_bound_region({:?}, {:?})", r, vid);
self.indices.insert(r, vid);
assert_eq!(self.indices.insert(r, vid), None);
}
/// Converts `r` into a local inference variable: `r` can either