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Don't hang when there's an infinite loop of outlives obligations

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This commit is contained in:
Michael Goulet 2024-02-01 18:04:16 +00:00
parent 7d1fda7b40
commit a371059933
2 changed files with 87 additions and 62 deletions
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31
compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
View file

@ -154,9 +154,19 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
} = *self;
let mut outlives_predicates = vec![(predicate, constraint_category)];
while let Some((ty::OutlivesPredicate(k1, r2), constraint_category)) =
outlives_predicates.pop()
{
for iteration in 0.. {
if outlives_predicates.is_empty() {
break;
}
if !self.tcx.recursion_limit().value_within_limit(iteration) {
bug!(
"FIXME(-Znext-solver): Overflowed when processing region obligations: {outlives_predicates:#?}"
);
}
let mut next_outlives_predicates = vec![];
for (ty::OutlivesPredicate(k1, r2), constraint_category) in outlives_predicates {
match k1.unpack() {
GenericArgKind::Lifetime(r1) => {
let r1_vid = self.to_region_vid(r1);
@ -196,9 +206,10 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
if let Some(constraints) = constraints {
assert!(
constraints.member_constraints.is_empty(),
"FIXME(-Znext-solver): How do I handle these?"
"no member constraints expected from normalizing: {:#?}",
constraints.member_constraints
);
outlives_predicates
next_outlives_predicates
.extend(constraints.outlives.iter().copied());
}
}
@ -217,12 +228,20 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
Some(implicit_region_bound),
known_type_outlives_obligations,
)
.type_must_outlive(origin, t1, r2, constraint_category);
.type_must_outlive(
origin,
t1,
r2,
constraint_category,
);
}
GenericArgKind::Const(_) => unreachable!(),
}
}
outlives_predicates = next_outlives_predicates;
}
}
/// Placeholder regions need to be converted eagerly because it may

8
compiler/rustc_infer/src/infer/outlives/obligations.rs
View file

@ -154,12 +154,18 @@ impl<'tcx> InferCtxt<'tcx> {
.map_err(|e| (e, SubregionOrigin::AscribeUserTypeProvePredicate(DUMMY_SP)))?;
// Must loop since the process of normalizing may itself register region obligations.
loop {
for iteration in 0.. {
let my_region_obligations = self.take_registered_region_obligations();
if my_region_obligations.is_empty() {
break;
}
if !self.tcx.recursion_limit().value_within_limit(iteration) {
bug!(
"FIXME(-Znext-solver): Overflowed when processing region obligations: {my_region_obligations:#?}"
);
}
for RegionObligation { sup_type, sub_region, origin } in my_region_obligations {
let sup_type = deeply_normalize_ty(sup_type, origin.clone())
.map_err(|e| (e, origin.clone()))?;