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Auto merge of #144446 - nnethercote:opt-region-constraints, r=lcnr

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Optimize region constraints

r? `@lcnr`
This commit is contained in:
bors 2025-08-01 04:06:21 +00:00
commit 6c02dd4eae
11 changed files with 229 additions and 239 deletions
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40
src/librustdoc/clean/auto_trait.rs
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@ -1,6 +1,6 @@
use rustc_data_structures::fx::{FxIndexMap, FxIndexSet, IndexEntry};
use rustc_hir as hir;
use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
use rustc_infer::infer::region_constraints::{ConstraintKind, RegionConstraintData};
use rustc_middle::bug;
use rustc_middle::ty::{self, Region, Ty, fold_regions};
use rustc_span::def_id::DefId;
@ -233,31 +233,35 @@ fn clean_region_outlives_constraints<'tcx>(
// Each `RegionTarget` (a `RegionVid` or a `Region`) maps to its smaller and larger regions.
// Note that "larger" regions correspond to sub regions in the surface language.
// E.g., in `'a: 'b`, `'a` is the larger region.
for (constraint, _) in &regions.constraints {
match *constraint {
Constraint::VarSubVar(vid1, vid2) => {
let deps1 = map.entry(RegionTarget::RegionVid(vid1)).or_default();
deps1.larger.insert(RegionTarget::RegionVid(vid2));
for (c, _) in &regions.constraints {
match c.kind {
ConstraintKind::VarSubVar => {
let sub_vid = c.sub.as_var();
let sup_vid = c.sup.as_var();
let deps1 = map.entry(RegionTarget::RegionVid(sub_vid)).or_default();
deps1.larger.insert(RegionTarget::RegionVid(sup_vid));
let deps2 = map.entry(RegionTarget::RegionVid(vid2)).or_default();
deps2.smaller.insert(RegionTarget::RegionVid(vid1));
let deps2 = map.entry(RegionTarget::RegionVid(sup_vid)).or_default();
deps2.smaller.insert(RegionTarget::RegionVid(sub_vid));
}
Constraint::RegSubVar(region, vid) => {
let deps = map.entry(RegionTarget::RegionVid(vid)).or_default();
deps.smaller.insert(RegionTarget::Region(region));
ConstraintKind::RegSubVar => {
let sup_vid = c.sup.as_var();
let deps = map.entry(RegionTarget::RegionVid(sup_vid)).or_default();
deps.smaller.insert(RegionTarget::Region(c.sub));
}
Constraint::VarSubReg(vid, region) => {
let deps = map.entry(RegionTarget::RegionVid(vid)).or_default();
deps.larger.insert(RegionTarget::Region(region));
ConstraintKind::VarSubReg => {
let sub_vid = c.sub.as_var();
let deps = map.entry(RegionTarget::RegionVid(sub_vid)).or_default();
deps.larger.insert(RegionTarget::Region(c.sup));
}
Constraint::RegSubReg(r1, r2) => {
ConstraintKind::RegSubReg => {
// The constraint is already in the form that we want, so we're done with it
// The desired order is [larger, smaller], so flip them.
if early_bound_region_name(r1) != early_bound_region_name(r2) {
if early_bound_region_name(c.sub) != early_bound_region_name(c.sup) {
outlives_predicates
.entry(early_bound_region_name(r2).expect("no region_name found"))
.entry(early_bound_region_name(c.sup).expect("no region_name found"))
.or_default()
.push(r1);
.push(c.sub);
}
}
}