diff --git a/compiler/rustc_borrowck/src/constraints/graph.rs b/compiler/rustc_borrowck/src/constraints/graph.rs
index 609fbc2bc15..385f153174c 100644
--- a/compiler/rustc_borrowck/src/constraints/graph.rs
+++ b/compiler/rustc_borrowck/src/constraints/graph.rs
@@ -163,6 +163,7 @@ impl<'s, 'tcx, D: ConstraintGraphDirecton> Iterator for Edges<'s, 'tcx, D> {
span: DUMMY_SP,
category: ConstraintCategory::Internal,
variance_info: VarianceDiagInfo::default(),
+ from_closure: false,
})
} else {
None
diff --git a/compiler/rustc_borrowck/src/constraints/mod.rs b/compiler/rustc_borrowck/src/constraints/mod.rs
index df04128135b..9d9c4abb0aa 100644
--- a/compiler/rustc_borrowck/src/constraints/mod.rs
+++ b/compiler/rustc_borrowck/src/constraints/mod.rs
@@ -96,6 +96,9 @@ pub struct OutlivesConstraint<'tcx> {
/// Variance diagnostic information
pub variance_info: VarianceDiagInfo<'tcx>,
+
+ /// If this constraint is promoted from closure requirements.
+ pub from_closure: bool,
}
impl<'tcx> fmt::Debug for OutlivesConstraint<'tcx> {
diff --git a/compiler/rustc_borrowck/src/nll.rs b/compiler/rustc_borrowck/src/nll.rs
index 08fdd28eb01..4e0205f8d43 100644
--- a/compiler/rustc_borrowck/src/nll.rs
+++ b/compiler/rustc_borrowck/src/nll.rs
@@ -242,7 +242,6 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
mut liveness_constraints,
outlives_constraints,
member_constraints,
- closure_bounds_mapping,
universe_causes,
type_tests,
} = constraints;
@@ -264,7 +263,6 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
universal_region_relations,
outlives_constraints,
member_constraints,
- closure_bounds_mapping,
universe_causes,
type_tests,
liveness_constraints,
diff --git a/compiler/rustc_borrowck/src/region_infer/dump_mir.rs b/compiler/rustc_borrowck/src/region_infer/dump_mir.rs
index fe5193102f9..cc945099952 100644
--- a/compiler/rustc_borrowck/src/region_infer/dump_mir.rs
+++ b/compiler/rustc_borrowck/src/region_infer/dump_mir.rs
@@ -74,8 +74,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
let mut constraints: Vec<_> = self.constraints.outlives().iter().collect();
constraints.sort_by_key(|c| (c.sup, c.sub));
for constraint in &constraints {
- let OutlivesConstraint { sup, sub, locations, category, span, variance_info: _ } =
- constraint;
+ let OutlivesConstraint { sup, sub, locations, category, span, .. } = constraint;
let (name, arg) = match locations {
Locations::All(span) => {
("All", tcx.sess.source_map().span_to_embeddable_string(*span))
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 0e7f243bcf3..6782fc0665f 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -6,10 +6,9 @@ use rustc_data_structures::frozen::Frozen;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::graph::scc::Sccs;
use rustc_errors::Diagnostic;
-use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
+use rustc_hir::def_id::CRATE_DEF_ID;
use rustc_hir::CRATE_HIR_ID;
use rustc_index::vec::IndexVec;
-use rustc_infer::infer::canonical::QueryOutlivesConstraint;
use rustc_infer::infer::outlives::test_type_match;
use rustc_infer::infer::region_constraints::{GenericKind, VarInfos, VerifyBound, VerifyIfEq};
use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin, RegionVariableOrigin};
@@ -19,9 +18,7 @@ use rustc_middle::mir::{
};
use rustc_middle::traits::ObligationCause;
use rustc_middle::traits::ObligationCauseCode;
-use rustc_middle::ty::{
- self, subst::SubstsRef, RegionVid, Ty, TyCtxt, TypeFoldable, TypeVisitable,
-};
+use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable, TypeVisitable};
use rustc_span::Span;
use crate::{
@@ -89,10 +86,6 @@ pub struct RegionInferenceContext<'tcx> {
/// `member_region_scc`.
member_constraints_applied: Vec<AppliedMemberConstraint>,
- /// Map closure bounds to a `Span` that should be used for error reporting.
- closure_bounds_mapping:
- FxHashMap<Location, FxHashMap<(RegionVid, RegionVid), (ConstraintCategory<'tcx>, Span)>>,
-
/// Map universe indexes to information on why we created it.
universe_causes: FxHashMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
@@ -265,10 +258,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
outlives_constraints: OutlivesConstraintSet<'tcx>,
member_constraints_in: MemberConstraintSet<'tcx, RegionVid>,
- closure_bounds_mapping: FxHashMap<
- Location,
- FxHashMap<(RegionVid, RegionVid), (ConstraintCategory<'tcx>, Span)>,
- >,
universe_causes: FxHashMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
type_tests: Vec<TypeTest<'tcx>>,
liveness_constraints: LivenessValues<RegionVid>,
@@ -310,7 +299,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
rev_scc_graph: None,
member_constraints,
member_constraints_applied: Vec::new(),
- closure_bounds_mapping,
universe_causes,
scc_universes,
scc_representatives,
@@ -1804,18 +1792,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
}
}
- pub(crate) fn retrieve_closure_constraint_info(
- &self,
- constraint: OutlivesConstraint<'tcx>,
- ) -> Option<(ConstraintCategory<'tcx>, Span)> {
- match constraint.locations {
- Locations::All(_) => None,
- Locations::Single(loc) => {
- self.closure_bounds_mapping[&loc].get(&(constraint.sup, constraint.sub)).copied()
- }
- }
- }
-
/// Finds a good `ObligationCause` to blame for the fact that `fr1` outlives `fr2`.
pub(crate) fn find_outlives_blame_span(
&self,
@@ -1921,6 +1897,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
span: p_c.definition_span,
category: ConstraintCategory::OpaqueType,
variance_info: ty::VarianceDiagInfo::default(),
+ from_closure: false,
};
handle_constraint(constraint);
}
@@ -2066,31 +2043,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
// Classify each of the constraints along the path.
let mut categorized_path: Vec<BlameConstraint<'tcx>> = path
.iter()
- .map(|constraint| {
- let (category, span, from_closure, cause_code) =
- if constraint.category == ConstraintCategory::ClosureBounds {
- if let Some((category, span)) =
- self.retrieve_closure_constraint_info(*constraint)
- {
- (category, span, true, ObligationCauseCode::MiscObligation)
- } else {
- (
- constraint.category,
- constraint.span,
- false,
- ObligationCauseCode::MiscObligation,
- )
- }
- } else {
- (constraint.category, constraint.span, false, cause_code.clone())
- };
- BlameConstraint {
- category,
- from_closure,
- cause: ObligationCause::new(span, CRATE_HIR_ID, cause_code),
- variance_info: constraint.variance_info,
- outlives_constraint: *constraint,
- }
+ .map(|constraint| BlameConstraint {
+ category: constraint.category,
+ from_closure: constraint.from_closure,
+ cause: ObligationCause::new(constraint.span, CRATE_HIR_ID, cause_code.clone()),
+ variance_info: constraint.variance_info,
+ outlives_constraint: *constraint,
})
.collect();
debug!("categorized_path={:#?}", categorized_path);
@@ -2274,92 +2232,6 @@ impl<'tcx> RegionDefinition<'tcx> {
}
}
-pub trait ClosureRegionRequirementsExt<'tcx> {
- fn apply_requirements(
- &self,
- tcx: TyCtxt<'tcx>,
- closure_def_id: DefId,
- closure_substs: SubstsRef<'tcx>,
- ) -> Vec<QueryOutlivesConstraint<'tcx>>;
-}
-
-impl<'tcx> ClosureRegionRequirementsExt<'tcx> for ClosureRegionRequirements<'tcx> {
- /// Given an instance T of the closure type, this method
- /// instantiates the "extra" requirements that we computed for the
- /// closure into the inference context. This has the effect of
- /// adding new outlives obligations to existing variables.
- ///
- /// As described on `ClosureRegionRequirements`, the extra
- /// requirements are expressed in terms of regionvids that index
- /// into the free regions that appear on the closure type. So, to
- /// do this, we first copy those regions out from the type T into
- /// a vector. Then we can just index into that vector to extract
- /// out the corresponding region from T and apply the
- /// requirements.
- fn apply_requirements(
- &self,
- tcx: TyCtxt<'tcx>,
- closure_def_id: DefId,
- closure_substs: SubstsRef<'tcx>,
- ) -> Vec<QueryOutlivesConstraint<'tcx>> {
- debug!(
- "apply_requirements(closure_def_id={:?}, closure_substs={:?})",
- closure_def_id, closure_substs
- );
-
- // Extract the values of the free regions in `closure_substs`
- // into a vector. These are the regions that we will be
- // relating to one another.
- let closure_mapping = &UniversalRegions::closure_mapping(
- tcx,
- closure_substs,
- self.num_external_vids,
- closure_def_id.expect_local(),
- );
- debug!("apply_requirements: closure_mapping={:?}", closure_mapping);
-
- // Create the predicates.
- self.outlives_requirements
- .iter()
- .map(|outlives_requirement| {
- let outlived_region = closure_mapping[outlives_requirement.outlived_free_region];
-
- match outlives_requirement.subject {
- ClosureOutlivesSubject::Region(region) => {
- let region = closure_mapping[region];
- debug!(
- "apply_requirements: region={:?} \
- outlived_region={:?} \
- outlives_requirement={:?}",
- region, outlived_region, outlives_requirement,
- );
- (
- ty::Binder::dummy(ty::OutlivesPredicate(
- region.into(),
- outlived_region,
- )),
- ConstraintCategory::BoringNoLocation,
- )
- }
-
- ClosureOutlivesSubject::Ty(ty) => {
- debug!(
- "apply_requirements: ty={:?} \
- outlived_region={:?} \
- outlives_requirement={:?}",
- ty, outlived_region, outlives_requirement,
- );
- (
- ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), outlived_region)),
- ConstraintCategory::BoringNoLocation,
- )
- }
- }
- })
- .collect()
- }
-}
-
#[derive(Clone, Debug)]
pub struct BlameConstraint<'tcx> {
pub category: ConstraintCategory<'tcx>,
diff --git a/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
index d5bfc2f5208..88be80c0b55 100644
--- a/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
+++ b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
@@ -1,10 +1,10 @@
-use rustc_infer::infer::canonical::QueryOutlivesConstraint;
+use rustc_hir::def_id::DefId;
use rustc_infer::infer::canonical::QueryRegionConstraints;
use rustc_infer::infer::outlives::env::RegionBoundPairs;
use rustc_infer::infer::outlives::obligations::{TypeOutlives, TypeOutlivesDelegate};
use rustc_infer::infer::region_constraints::{GenericKind, VerifyBound};
use rustc_infer::infer::{self, InferCtxt, SubregionOrigin};
-use rustc_middle::mir::ConstraintCategory;
+use rustc_middle::mir::{ClosureOutlivesSubject, ClosureRegionRequirements, ConstraintCategory};
use rustc_middle::ty::subst::GenericArgKind;
use rustc_middle::ty::TypeFoldable;
use rustc_middle::ty::{self, TyCtxt};
@@ -38,6 +38,7 @@ pub(crate) struct ConstraintConversion<'a, 'tcx> {
locations: Locations,
span: Span,
category: ConstraintCategory<'tcx>,
+ from_closure: bool,
constraints: &'a mut MirTypeckRegionConstraints<'tcx>,
}
@@ -64,6 +65,7 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
span,
category,
constraints,
+ from_closure: false,
}
}
@@ -81,12 +83,62 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
}
self.constraints.member_constraints = tmp;
- for query_constraint in outlives {
- self.convert(query_constraint);
+ for (predicate, constraint_category) in outlives {
+ // At the moment, we never generate any "higher-ranked"
+ // region constraints like `for<'a> 'a: 'b`. At some point
+ // when we move to universes, we will, and this assertion
+ // will start to fail.
+ let predicate = predicate.no_bound_vars().unwrap_or_else(|| {
+ bug!("query_constraint {:?} contained bound vars", predicate,);
+ });
+
+ self.convert(predicate, *constraint_category);
}
}
- fn convert(&mut self, query_constraint: &QueryOutlivesConstraint<'tcx>) {
+ /// Given an instance of the closure type, this method instantiates the "extra" requirements
+ /// that we computed for the closure. This has the effect of adding new outlives obligations
+ /// to existing region variables in `closure_substs`.
+ #[instrument(skip(self), level = "debug")]
+ pub fn apply_closure_requirements(
+ &mut self,
+ closure_requirements: &ClosureRegionRequirements<'tcx>,
+ closure_def_id: DefId,
+ closure_substs: ty::SubstsRef<'tcx>,
+ ) {
+ // Extract the values of the free regions in `closure_substs`
+ // into a vector. These are the regions that we will be
+ // relating to one another.
+ let closure_mapping = &UniversalRegions::closure_mapping(
+ self.tcx,
+ closure_substs,
+ closure_requirements.num_external_vids,
+ closure_def_id.expect_local(),
+ );
+ debug!(?closure_mapping);
+
+ // Create the predicates.
+ let backup = (self.category, self.span, self.from_closure);
+ self.from_closure = true;
+ for outlives_requirement in &closure_requirements.outlives_requirements {
+ let outlived_region = closure_mapping[outlives_requirement.outlived_free_region];
+ let subject = match outlives_requirement.subject {
+ ClosureOutlivesSubject::Region(re) => closure_mapping[re].into(),
+ ClosureOutlivesSubject::Ty(ty) => ty.into(),
+ };
+
+ self.category = outlives_requirement.category;
+ self.span = outlives_requirement.blame_span;
+ self.convert(ty::OutlivesPredicate(subject, outlived_region), self.category);
+ }
+ (self.category, self.span, self.from_closure) = backup;
+ }
+
+ fn convert(
+ &mut self,
+ predicate: ty::OutlivesPredicate<ty::GenericArg<'tcx>, ty::Region<'tcx>>,
+ constraint_category: ConstraintCategory<'tcx>,
+ ) {
debug!("generate: constraints at: {:#?}", self.locations);
// Extract out various useful fields we'll need below.
@@ -94,17 +146,7 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
tcx, region_bound_pairs, implicit_region_bound, param_env, ..
} = *self;
- // At the moment, we never generate any "higher-ranked"
- // region constraints like `for<'a> 'a: 'b`. At some point
- // when we move to universes, we will, and this assertion
- // will start to fail.
- let ty::OutlivesPredicate(k1, r2) =
- query_constraint.0.no_bound_vars().unwrap_or_else(|| {
- bug!("query_constraint {:?} contained bound vars", query_constraint,);
- });
-
- let constraint_category = query_constraint.1;
-
+ let ty::OutlivesPredicate(k1, r2) = predicate;
match k1.unpack() {
GenericArgKind::Lifetime(r1) => {
let r1_vid = self.to_region_vid(r1);
@@ -188,6 +230,7 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
sub,
sup,
variance_info: ty::VarianceDiagInfo::default(),
+ from_closure: self.from_closure,
});
}
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 3c1c3ab45ce..3d9e08b4ca7 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -27,7 +27,7 @@ use rustc_middle::mir::AssertKind;
use rustc_middle::mir::*;
use rustc_middle::ty::adjustment::PointerCast;
use rustc_middle::ty::cast::CastTy;
-use rustc_middle::ty::subst::{GenericArgKind, SubstsRef, UserSubsts};
+use rustc_middle::ty::subst::{SubstsRef, UserSubsts};
use rustc_middle::ty::visit::TypeVisitable;
use rustc_middle::ty::{
self, Binder, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, Dynamic,
@@ -61,7 +61,7 @@ use crate::{
region_infer::values::{
LivenessValues, PlaceholderIndex, PlaceholderIndices, RegionValueElements,
},
- region_infer::{ClosureRegionRequirementsExt, TypeTest},
+ region_infer::TypeTest,
type_check::free_region_relations::{CreateResult, UniversalRegionRelations},
universal_regions::{DefiningTy, UniversalRegions},
Upvar,
@@ -144,7 +144,6 @@ pub(crate) fn type_check<'mir, 'tcx>(
liveness_constraints: LivenessValues::new(elements.clone()),
outlives_constraints: OutlivesConstraintSet::default(),
member_constraints: MemberConstraintSet::default(),
- closure_bounds_mapping: Default::default(),
type_tests: Vec::default(),
universe_causes: FxHashMap::default(),
};
@@ -585,7 +584,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
let all_facts = &mut None;
let mut constraints = Default::default();
let mut type_tests = Default::default();
- let mut closure_bounds = Default::default();
let mut liveness_constraints =
LivenessValues::new(Rc::new(RegionValueElements::new(&promoted_body)));
// Don't try to add borrow_region facts for the promoted MIR
@@ -597,10 +595,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
&mut constraints,
);
mem::swap(&mut this.cx.borrowck_context.constraints.type_tests, &mut type_tests);
- mem::swap(
- &mut this.cx.borrowck_context.constraints.closure_bounds_mapping,
- &mut closure_bounds,
- );
mem::swap(
&mut this.cx.borrowck_context.constraints.liveness_constraints,
&mut liveness_constraints,
@@ -653,18 +647,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
.add_element(region, location);
}
}
-
- if !closure_bounds.is_empty() {
- let combined_bounds_mapping =
- closure_bounds.into_iter().flat_map(|(_, value)| value).collect();
- let existing = self
- .cx
- .borrowck_context
- .constraints
- .closure_bounds_mapping
- .insert(location, combined_bounds_mapping);
- assert!(existing.is_none(), "Multiple promoteds/closures at the same location.");
- }
}
fn sanitize_projection(
@@ -941,9 +923,6 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> {
pub(crate) member_constraints: MemberConstraintSet<'tcx, RegionVid>,
- pub(crate) closure_bounds_mapping:
- FxHashMap<Location, FxHashMap<(RegionVid, RegionVid), (ConstraintCategory<'tcx>, Span)>>,
-
pub(crate) universe_causes: FxHashMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
pub(crate) type_tests: Vec<TypeTest<'tcx>>,
@@ -2562,6 +2541,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
span: location.to_locations().span(body),
category,
variance_info: ty::VarianceDiagInfo::default(),
+ from_closure: false,
});
match mutbl {
@@ -2679,62 +2659,22 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
substs: SubstsRef<'tcx>,
location: Location,
) -> ty::InstantiatedPredicates<'tcx> {
- if let Some(ref closure_region_requirements) = tcx.mir_borrowck(def_id).closure_requirements
- {
- let closure_constraints = QueryRegionConstraints {
- outlives: closure_region_requirements.apply_requirements(
- tcx,
- def_id.to_def_id(),
- substs,
- ),
-
- // Presently, closures never propagate member
- // constraints to their parents -- they are enforced
- // locally. This is largely a non-issue as member
- // constraints only come from `-> impl Trait` and
- // friends which don't appear (thus far...) in
- // closures.
- member_constraints: vec![],
- };
-
- let bounds_mapping = closure_constraints
- .outlives
- .iter()
- .enumerate()
- .filter_map(|(idx, constraint)| {
- let ty::OutlivesPredicate(k1, r2) =
- constraint.0.no_bound_vars().unwrap_or_else(|| {
- bug!("query_constraint {:?} contained bound vars", constraint,);
- });
-
- match k1.unpack() {
- GenericArgKind::Lifetime(r1) => {
- // constraint is r1: r2
- let r1_vid = self.borrowck_context.universal_regions.to_region_vid(r1);
- let r2_vid = self.borrowck_context.universal_regions.to_region_vid(r2);
- let outlives_requirements =
- &closure_region_requirements.outlives_requirements[idx];
- Some((
- (r1_vid, r2_vid),
- (outlives_requirements.category, outlives_requirements.blame_span),
- ))
- }
- GenericArgKind::Type(_) | GenericArgKind::Const(_) => None,
- }
- })
- .collect();
-
- let existing = self
- .borrowck_context
- .constraints
- .closure_bounds_mapping
- .insert(location, bounds_mapping);
- assert!(existing.is_none(), "Multiple closures at the same location.");
-
- self.push_region_constraints(
+ if let Some(ref closure_requirements) = tcx.mir_borrowck(def_id).closure_requirements {
+ constraint_conversion::ConstraintConversion::new(
+ self.infcx,
+ self.borrowck_context.universal_regions,
+ self.region_bound_pairs,
+ self.implicit_region_bound,
+ self.param_env,
location.to_locations(),
- ConstraintCategory::ClosureBounds,
- &closure_constraints,
+ DUMMY_SP, // irrelevant; will be overrided.
+ ConstraintCategory::Boring, // same as above.
+ &mut self.borrowck_context.constraints,
+ )
+ .apply_closure_requirements(
+ &closure_requirements,
+ def_id.to_def_id(),
+ substs,
);
}
diff --git a/compiler/rustc_borrowck/src/type_check/relate_tys.rs b/compiler/rustc_borrowck/src/type_check/relate_tys.rs
index 4f2dc263bf5..94d51032866 100644
--- a/compiler/rustc_borrowck/src/type_check/relate_tys.rs
+++ b/compiler/rustc_borrowck/src/type_check/relate_tys.rs
@@ -136,6 +136,7 @@ impl<'tcx> TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx>
span: self.locations.span(self.type_checker.body),
category: self.category,
variance_info: info,
+ from_closure: false,
},
);
}
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
index 0195a693e5f..1260a656c98 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
@@ -167,7 +167,7 @@ LL | | T: Anything<'b, 'b>,
= note: defining type: two_regions::<'_#1r, T>
error: lifetime may not live long enough
- --> $DIR/projection-two-region-trait-bound-closure.rs:87:29
+ --> $DIR/projection-two-region-trait-bound-closure.rs:87:5
|
LL | fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
| -- -- lifetime `'b` defined here
@@ -175,9 +175,12 @@ LL | fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
| lifetime `'a` defined here
...
LL | with_signature(cell, t, |cell, t| require(cell, t));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^ closure body requires that `'b` must outlive `'a`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'b` must outlive `'a`
|
= help: consider adding the following bound: `'b: 'a`
+ = note: requirement occurs because of the type `Cell<&'_#8r ()>`, which makes the generic argument `&'_#8r ()` invariant
+ = note: the struct `Cell<T>` is invariant over the parameter `T`
+ = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
note: external requirements
--> $DIR/projection-two-region-trait-bound-closure.rs:97:29