diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs
index 6ea84620bbed8..16814950b0d98 100644
--- a/compiler/rustc_borrowck/src/dataflow.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -272,21 +272,28 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
loan_issued_at: Location,
) {
let sccs = self.regioncx.constraint_sccs();
+ let universal_regions = self.regioncx.universal_regions();
let issuing_region_scc = sccs.scc(issuing_region);
// We first handle the cases where the loan doesn't go out of scope, depending on the issuing
// region's successors.
for scc in sccs.depth_first_search(issuing_region_scc) {
- // 1. Via member constraints
+ // 1. Via applied member constraints
//
// The issuing region can flow into the choice regions, and they are either:
// - placeholders or free regions themselves,
// - or also transitively outlive a free region.
//
- // That is to say, if there are member constraints here, the loan escapes the function
- // and cannot go out of scope. We can early return.
- if self.regioncx.scc_has_member_constraints(scc) {
- return;
+ // That is to say, if there are applied member constraints here, the loan escapes the
+ // function and cannot go out of scope. We could early return here.
+ //
+ // For additional insurance via fuzzing and crater, we verify that the constraint's min
+ // choice indeed escapes the function. In the future, we could e.g. turn this check into
+ // a debug assert and early return as an optimization.
+ for constraint in self.regioncx.applied_member_constraints(scc) {
+ if universal_regions.is_universal_region(constraint.min_choice) {
+ return;
+ }
}
// 2. Via regions that are live at all points: placeholders and free regions.
@@ -413,12 +420,12 @@ impl<'a, 'tcx> Borrows<'a, 'tcx> {
let mut polonius_prec = PoloniusOutOfScopePrecomputer::new(body, regioncx);
for (loan_idx, loan_data) in borrow_set.iter_enumerated() {
let issuing_region = loan_data.region;
- let issued_location = loan_data.reserve_location;
+ let loan_issued_at = loan_data.reserve_location;
polonius_prec.precompute_loans_out_of_scope(
loan_idx,
issuing_region,
- issued_location,
+ loan_issued_at,
);
}
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 96cbe98c21694..05c2cbd49692c 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -644,11 +644,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
self.scc_universes[scc]
}
- /// Once region solving has completed, this function will return
- /// the member constraints that were applied to the value of a given
- /// region `r`. See `AppliedMemberConstraint`.
- pub(crate) fn applied_member_constraints(&self, r: RegionVid) -> &[AppliedMemberConstraint] {
- let scc = self.constraint_sccs.scc(r);
+ /// Once region solving has completed, this function will return the member constraints that
+ /// were applied to the value of a given SCC `scc`. See `AppliedMemberConstraint`.
+ pub(crate) fn applied_member_constraints(
+ &self,
+ scc: ConstraintSccIndex,
+ ) -> &[AppliedMemberConstraint] {
binary_search_util::binary_search_slice(
&self.member_constraints_applied,
|applied| applied.member_region_scc,
@@ -1945,7 +1946,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
// Member constraints can also give rise to `'r: 'x` edges that
// were not part of the graph initially, so watch out for those.
// (But they are extremely rare; this loop is very cold.)
- for constraint in self.applied_member_constraints(r) {
+ for constraint in self.applied_member_constraints(self.constraint_sccs.scc(r)) {
let p_c = &self.member_constraints[constraint.member_constraint_index];
let constraint = OutlivesConstraint {
sup: r,
@@ -2292,11 +2293,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
self.constraint_sccs.as_ref()
}
- /// Returns whether the given SCC has any member constraints.
- pub(crate) fn scc_has_member_constraints(&self, scc: ConstraintSccIndex) -> bool {
- self.member_constraints.indices(scc).next().is_some()
- }
-
/// Returns whether the given SCC is live at all points: whether the representative is a
/// placeholder or a free region.
pub(crate) fn scc_is_live_at_all_points(&self, scc: ConstraintSccIndex) -> bool {
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index bbba800e84081..ef0ad69c4a2c3 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -3420,9 +3420,10 @@ impl DumpMonoStatsFormat {
/// `-Zpolonius` values, enabling the borrow checker polonius analysis, and which version: legacy,
/// or future prototype.
-#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Hash, Debug, Default)]
pub enum Polonius {
/// The default value: disabled.
+ #[default]
Off,
/// Legacy version, using datalog and the `polonius-engine` crate. Historical value for `-Zpolonius`.
@@ -3432,12 +3433,6 @@ pub enum Polonius {
Next,
}
-impl Default for Polonius {
- fn default() -> Self {
- Polonius::Off
- }
-}
-
impl Polonius {
/// Returns whether the legacy version of polonius is enabled
pub fn is_legacy_enabled(&self) -> bool {
diff --git a/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.nll.stderr b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.nll.stderr
new file mode 100644
index 0000000000000..6f9b330316378
--- /dev/null
+++ b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.nll.stderr
@@ -0,0 +1,36 @@
+error[E0046]: not all trait items implemented, missing: `call`
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:18:1
+ |
+LL | fn call(x: Self) -> Self::Output;
+ | --------------------------------- `call` from trait
+...
+LL | impl<T: PlusOne> Callable for T {
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `call` in implementation
+
+error: unconstrained opaque type
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:22:19
+ |
+LL | type Output = impl PlusOne;
+ | ^^^^^^^^^^^^
+ |
+ = note: `Output` must be used in combination with a concrete type within the same impl
+
+error[E0700]: hidden type for `impl PlusOne` captures lifetime that does not appear in bounds
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:28:5
+ |
+LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne {
+ | -- ------------ opaque type defined here
+ | |
+ | hidden type `<&'a mut i32 as Callable>::Output` captures the lifetime `'a` as defined here
+LL | <&mut i32 as Callable>::call(y)
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+help: to declare that `impl PlusOne` captures `'a`, you can add an explicit `'a` lifetime bound
+ |
+LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne + 'a {
+ | ++++
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0046, E0700.
+For more information about an error, try `rustc --explain E0046`.
diff --git a/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.polonius.stderr b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.polonius.stderr
new file mode 100644
index 0000000000000..6f9b330316378
--- /dev/null
+++ b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.polonius.stderr
@@ -0,0 +1,36 @@
+error[E0046]: not all trait items implemented, missing: `call`
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:18:1
+ |
+LL | fn call(x: Self) -> Self::Output;
+ | --------------------------------- `call` from trait
+...
+LL | impl<T: PlusOne> Callable for T {
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `call` in implementation
+
+error: unconstrained opaque type
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:22:19
+ |
+LL | type Output = impl PlusOne;
+ | ^^^^^^^^^^^^
+ |
+ = note: `Output` must be used in combination with a concrete type within the same impl
+
+error[E0700]: hidden type for `impl PlusOne` captures lifetime that does not appear in bounds
+ --> $DIR/location-insensitive-scopes-issue-116657.rs:28:5
+ |
+LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne {
+ | -- ------------ opaque type defined here
+ | |
+ | hidden type `<&'a mut i32 as Callable>::Output` captures the lifetime `'a` as defined here
+LL | <&mut i32 as Callable>::call(y)
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+help: to declare that `impl PlusOne` captures `'a`, you can add an explicit `'a` lifetime bound
+ |
+LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne + 'a {
+ | ++++
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0046, E0700.
+For more information about an error, try `rustc --explain E0046`.
diff --git a/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.rs b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.rs
new file mode 100644
index 0000000000000..ec17e0b093b38
--- /dev/null
+++ b/tests/ui/nll/polonius/location-insensitive-scopes-issue-116657.rs
@@ -0,0 +1,33 @@
+// This is a non-regression test for issue #116657, where NLL and `-Zpolonius=next` computed
+// different loan scopes when a member constraint was not ultimately applied.
+
+// revisions: nll polonius
+// [polonius] compile-flags: -Zpolonius=next
+
+#![feature(impl_trait_in_assoc_type)]
+
+trait Callable {
+ type Output;
+ fn call(x: Self) -> Self::Output;
+}
+
+trait PlusOne {}
+
+impl<'a> PlusOne for &'a mut i32 {}
+
+impl<T: PlusOne> Callable for T {
+ //[nll]~^ ERROR not all trait items implemented
+ //[polonius]~^^ ERROR not all trait items implemented
+
+ type Output = impl PlusOne;
+ //[nll]~^ ERROR unconstrained opaque type
+ //[polonius]~^^ ERROR unconstrained opaque type
+}
+
+fn test<'a>(y: &'a mut i32) -> impl PlusOne {
+ <&mut i32 as Callable>::call(y)
+ //[nll]~^ ERROR hidden type for `impl PlusOne` captures lifetime
+ //[polonius]~^^ ERROR hidden type for `impl PlusOne` captures lifetime
+}
+
+fn main() {}