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Remove unnecessary lifetime from LeakCheck.

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`LeakCheck` can own `mini_graph` and `rcc` instead of holding references
to them. This requires inlining `assign_scc_value` to avoid a borrowck
error, but that's fine because it has a single call site.
This commit is contained in:
Nicholas Nethercote 2024-10-03 13:58:13 +10:00
parent 85507cffc3
commit e8a0bd6549
1 changed files with 22 additions and 32 deletions
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54
compiler/rustc_infer/src/infer/region_constraints/leak_check.rs
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@ -73,7 +73,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
/// * R: P1, R: P2, as above
#[instrument(level = "debug", skip(self, tcx, only_consider_snapshot), ret)]
pub fn leak_check(
&mut self,
self,
tcx: TyCtxt<'tcx>,
outer_universe: ty::UniverseIndex,
max_universe: ty::UniverseIndex,
@ -83,7 +83,7 @@ pub fn leak_check(
return Ok(());
}
let mini_graph = &MiniGraph::new(tcx, self, only_consider_snapshot);
let mini_graph = MiniGraph::new(tcx, &self, only_consider_snapshot);
let mut leak_check = LeakCheck::new(tcx, outer_universe, max_universe, mini_graph, self);
leak_check.assign_placeholder_values()?;
@ -92,11 +92,11 @@ pub fn leak_check(
}
}
struct LeakCheck<'a, 'b, 'tcx> {
struct LeakCheck<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
outer_universe: ty::UniverseIndex,
mini_graph: &'a MiniGraph<'tcx>,
rcc: &'a mut RegionConstraintCollector<'b, 'tcx>,
mini_graph: MiniGraph<'tcx>,
rcc: RegionConstraintCollector<'a, 'tcx>,
// Initially, for each SCC S, stores a placeholder `P` such that `S = P`
// must hold.
@ -115,26 +115,27 @@ struct LeakCheck<'a, 'b, 'tcx> {
// either the placeholder `P1` or the empty region in that same universe.
//
// To detect errors, we look for an SCC S where the values in
// `scc_values[S]` (if any) cannot be stored into `scc_universes[S]`.
// `scc_placeholders[S]` (if any) cannot be stored into `scc_universes[S]`.
scc_universes: IndexVec<LeakCheckScc, SccUniverse<'tcx>>,
}
impl<'a, 'b, 'tcx> LeakCheck<'a, 'b, 'tcx> {
impl<'a, 'tcx> LeakCheck<'a, 'tcx> {
fn new(
tcx: TyCtxt<'tcx>,
outer_universe: ty::UniverseIndex,
max_universe: ty::UniverseIndex,
mini_graph: &'a MiniGraph<'tcx>,
rcc: &'a mut RegionConstraintCollector<'b, 'tcx>,
mini_graph: MiniGraph<'tcx>,
rcc: RegionConstraintCollector<'a, 'tcx>,
) -> Self {
let dummy_scc_universe = SccUniverse { universe: max_universe, region: None };
let num_sccs = mini_graph.sccs.num_sccs();
Self {
tcx,
outer_universe,
mini_graph,
rcc,
scc_placeholders: IndexVec::from_elem_n(None, mini_graph.sccs.num_sccs()),
scc_universes: IndexVec::from_elem_n(dummy_scc_universe, mini_graph.sccs.num_sccs()),
scc_placeholders: IndexVec::from_elem_n(None, num_sccs),
scc_universes: IndexVec::from_elem_n(dummy_scc_universe, num_sccs),
}
}
@ -156,7 +157,16 @@ fn assign_placeholder_values(&mut self) -> RelateResult<'tcx, ()> {
// Detect those SCCs that directly contain a placeholder
if let ty::RePlaceholder(placeholder) = **region {
if self.outer_universe.cannot_name(placeholder.universe) {
self.assign_scc_value(scc, placeholder)?;
// Update `scc_placeholders` to account for the fact that `P: S` must hold.
match self.scc_placeholders[scc] {
Some(p) => {
assert_ne!(p, placeholder);
return Err(self.placeholder_error(p, placeholder));
}
None => {
self.scc_placeholders[scc] = Some(placeholder);
}
}
}
}
}
@ -164,26 +174,6 @@ fn assign_placeholder_values(&mut self) -> RelateResult<'tcx, ()> {
Ok(())
}
// assign_scc_value(S, P): Update `scc_values` to account for the fact that `P: S` must hold.
// This may create an error.
fn assign_scc_value(
&mut self,
scc: LeakCheckScc,
placeholder: ty::PlaceholderRegion,
) -> RelateResult<'tcx, ()> {
match self.scc_placeholders[scc] {
Some(p) => {
assert_ne!(p, placeholder);
return Err(self.placeholder_error(p, placeholder));
}
None => {
self.scc_placeholders[scc] = Some(placeholder);
}
};
Ok(())
}
/// For each SCC S, iterate over each successor S1 where `S: S1`:
///
/// * Compute