bjoernager/rust
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Wrap recursive predicate evaluation with ensure_sufficient_stack

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I haven't been able to come up with a minimized test case for #76770,
but this fixes a stack overflow in rustc as well.
This commit is contained in:
Aaron Hill 2020-09-18 11:09:00 -04:00
parent 2c69266c06
commit 6a96aea36a
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GPG key ID: B4087E510E98B164
1 changed files with 147 additions and 133 deletions
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24
compiler/rustc_trait_selection/src/traits/select/mod.rs
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@ -450,6 +450,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
None => self.check_recursion_limit(&obligation, &obligation)?,
}
ensure_sufficient_stack(|| {
match obligation.predicate.skip_binders() {
ty::PredicateAtom::Trait(t, _) => {
let t = ty::Binder::bind(t);
@ -483,7 +484,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
) {
Some(mut obligations) => {
self.add_depth(obligations.iter_mut(), obligation.recursion_depth);
self.evaluate_predicates_recursively(previous_stack, obligations.into_iter())
self.evaluate_predicates_recursively(
previous_stack,
obligations.into_iter(),
)
}
None => Ok(EvaluatedToAmbig),
},
@ -557,7 +561,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
ty::PredicateAtom::ConstEquate(c1, c2) => {
debug!("evaluate_predicate_recursively: equating consts c1={:?} c2={:?}", c1, c2);
debug!(
"evaluate_predicate_recursively: equating consts c1={:?} c2={:?}",
c1, c2
);
let evaluate = |c: &'tcx ty::Const<'tcx>| {
if let ty::ConstKind::Unevaluated(def, substs, promoted) = c.val {
@ -577,17 +584,23 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
match (evaluate(c1), evaluate(c2)) {
(Ok(c1), Ok(c2)) => {
match self.infcx().at(&obligation.cause, obligation.param_env).eq(c1, c2) {
match self
.infcx()
.at(&obligation.cause, obligation.param_env)
.eq(c1, c2)
{
Ok(_) => Ok(EvaluatedToOk),
Err(_) => Ok(EvaluatedToErr),
}
}
(Err(ErrorHandled::Reported(ErrorReported)), _)
| (_, Err(ErrorHandled::Reported(ErrorReported))) => Ok(EvaluatedToErr),
(Err(ErrorHandled::Linted), _) | (_, Err(ErrorHandled::Linted)) => span_bug!(
(Err(ErrorHandled::Linted), _) | (_, Err(ErrorHandled::Linted)) => {
span_bug!(
obligation.cause.span(self.tcx()),
"ConstEquate: const_eval_resolve returned an unexpected error"
),
)
}
(Err(ErrorHandled::TooGeneric), _) | (_, Err(ErrorHandled::TooGeneric)) => {
Ok(EvaluatedToAmbig)
}
@ -597,6 +610,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
bug!("TypeWellFormedFromEnv is only used for chalk")
}
}
})
}
fn evaluate_trait_predicate_recursively<'o>(