Greatly simplify lifetime captures in edition 2024

compiler/rustc_abi/src/lib.rs

@@ -1345,7 +1345,7 @@ impl<FieldIdx: Idx> FieldsShape<FieldIdx> {
 
     /// Gets source indices of the fields by increasing offsets.
     #[inline]
-    pub fn index_by_increasing_offset(&self) -> impl ExactSizeIterator<Item = usize> + '_ {
+    pub fn index_by_increasing_offset(&self) -> impl ExactSizeIterator<Item = usize> {
         let mut inverse_small = [0u8; 64];
         let mut inverse_big = IndexVec::new();
         let use_small = self.count() <= inverse_small.len();

compiler/rustc_ast_lowering/src/lib.rs

@@ -45,7 +45,6 @@ use std::sync::Arc;
 
 use rustc_ast::node_id::NodeMap;
 use rustc_ast::{self as ast, *};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -1821,11 +1820,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.new_named_lifetime_with_res(new_id, ident, res)
     }
 
-    fn lower_generic_params_mut<'s>(
-        &'s mut self,
-        params: &'s [GenericParam],
+    fn lower_generic_params_mut(
+        &mut self,
+        params: &[GenericParam],
         source: hir::GenericParamSource,
-    ) -> impl Iterator<Item = hir::GenericParam<'hir>> + Captures<'a> + Captures<'s> {
+    ) -> impl Iterator<Item = hir::GenericParam<'hir>> {
         params.iter().map(move |param| self.lower_generic_param(param, source))
     }
 
@@ -1986,11 +1985,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.arena.alloc_from_iter(self.lower_param_bounds_mut(bounds, itctx))
     }
 
-    fn lower_param_bounds_mut<'s>(
-        &'s mut self,
-        bounds: &'s [GenericBound],
+    fn lower_param_bounds_mut(
+        &mut self,
+        bounds: &[GenericBound],
         itctx: ImplTraitContext,
-    ) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> {
+    ) -> impl Iterator<Item = hir::GenericBound<'hir>> {
         bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx))
     }
 

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -4,25 +4,25 @@ use rustc_span::{Symbol, sym};
 
 use crate::session_diagnostics;
 
-pub fn allow_internal_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
-) -> impl Iterator<Item = Symbol> + 'a {
+pub fn allow_internal_unstable(
+    sess: &Session,
+    attrs: &[impl AttributeExt],
+) -> impl Iterator<Item = Symbol> {
     allow_unstable(sess, attrs, sym::allow_internal_unstable)
 }
 
-pub fn rustc_allow_const_fn_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
-) -> impl Iterator<Item = Symbol> + 'a {
+pub fn rustc_allow_const_fn_unstable(
+    sess: &Session,
+    attrs: &[impl AttributeExt],
+) -> impl Iterator<Item = Symbol> {
     allow_unstable(sess, attrs, sym::rustc_allow_const_fn_unstable)
 }
 
-fn allow_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
+fn allow_unstable(
+    sess: &Session,
+    attrs: &[impl AttributeExt],
     symbol: Symbol,
-) -> impl Iterator<Item = Symbol> + 'a {
+) -> impl Iterator<Item = Symbol> {
     let attrs = filter_by_name(attrs, symbol);
     let list = attrs
         .filter_map(move |attr| {

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -8,7 +8,6 @@ use std::ops::ControlFlow;
 
 use either::Either;
 use hir::{ClosureKind, Path};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, Diag, MultiSpan, struct_span_code_err};
@@ -3530,10 +3529,10 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         location: Location,
         mpi: MovePathIndex,
     ) -> (Vec<MoveSite>, Vec<Location>) {
-        fn predecessor_locations<'a, 'tcx>(
-            body: &'a mir::Body<'tcx>,
+        fn predecessor_locations<'tcx>(
+            body: &mir::Body<'tcx>,
             location: Location,
-        ) -> impl Iterator<Item = Location> + Captures<'tcx> + 'a {
+        ) -> impl Iterator<Item = Location> {
             if location.statement_index == 0 {
                 let predecessors = body.basic_blocks.predecessors()[location.block].to_vec();
                 Either::Left(predecessors.into_iter().map(move |bb| body.terminator_loc(bb)))

compiler/rustc_borrowck/src/member_constraints.rs

@@ -1,7 +1,6 @@
 use std::hash::Hash;
 use std::ops::Index;
 
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::ty::{self, Ty};
@@ -147,9 +146,7 @@ impl<'tcx, R> MemberConstraintSet<'tcx, R>
 where
     R: Copy + Hash + Eq,
 {
-    pub(crate) fn all_indices(
-        &self,
-    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
+    pub(crate) fn all_indices(&self) -> impl Iterator<Item = NllMemberConstraintIndex> {
         self.constraints.indices()
     }
 
@@ -159,7 +156,7 @@ where
     pub(crate) fn indices(
         &self,
         member_region_vid: R,
-    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
+    ) -> impl Iterator<Item = NllMemberConstraintIndex> {
         let mut next = self.first_constraints.get(&member_region_vid).cloned();
         std::iter::from_fn(move || -> Option<NllMemberConstraintIndex> {
             if let Some(current) = next {

compiler/rustc_borrowck/src/polonius/loan_liveness.rs

@@ -175,7 +175,7 @@ impl LocalizedConstraintGraph {
     }
 
     /// Returns the outgoing edges of a given node, not its transitive closure.
-    fn outgoing_edges(&self, node: LocalizedNode) -> impl Iterator<Item = LocalizedNode> + use<'_> {
+    fn outgoing_edges(&self, node: LocalizedNode) -> impl Iterator<Item = LocalizedNode> {
         // The outgoing edges are:
         // - the physical edges present at this node,
         // - the materialized logical edges that exist virtually at all points for this node's

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -576,9 +576,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// Returns an iterator over all the outlives constraints.
-    pub(crate) fn outlives_constraints(
-        &self,
-    ) -> impl Iterator<Item = OutlivesConstraint<'tcx>> + '_ {
+    pub(crate) fn outlives_constraints(&self) -> impl Iterator<Item = OutlivesConstraint<'tcx>> {
         self.constraints.outlives().iter().copied()
     }
 
@@ -615,10 +613,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.scc_values.region_value_str(scc)
     }
 
-    pub(crate) fn placeholders_contained_in<'a>(
-        &'a self,
+    pub(crate) fn placeholders_contained_in(
+        &self,
         r: RegionVid,
-    ) -> impl Iterator<Item = ty::PlaceholderRegion> + 'a {
+    ) -> impl Iterator<Item = ty::PlaceholderRegion> {
         let scc = self.constraint_sccs.scc(r);
         self.scc_values.placeholders_contained_in(scc)
     }

compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs

@@ -20,10 +20,7 @@ pub(crate) struct ReverseSccGraph {
 
 impl ReverseSccGraph {
     /// Find all universal regions that are required to outlive the given SCC.
-    pub(super) fn upper_bounds<'a>(
-        &'a self,
-        scc0: ConstraintSccIndex,
-    ) -> impl Iterator<Item = RegionVid> + 'a {
+    pub(super) fn upper_bounds(&self, scc0: ConstraintSccIndex) -> impl Iterator<Item = RegionVid> {
         let mut duplicates = FxIndexSet::default();
         graph::depth_first_search(&self.graph, scc0)
             .flat_map(move |scc1| {

compiler/rustc_borrowck/src/region_infer/values.rs

@@ -88,15 +88,15 @@ impl LivenessValues {
     }
 
     /// Iterate through each region that has a value in this set.
-    pub(crate) fn regions(&self) -> impl Iterator<Item = RegionVid> + '_ {
+    pub(crate) fn regions(&self) -> impl Iterator<Item = RegionVid> {
         self.points.as_ref().expect("use with_specific_points").rows()
     }
 
     /// Iterate through each region that has a value in this set.
     // We are passing query instability implications to the caller.
     #[rustc_lint_query_instability]
     #[allow(rustc::potential_query_instability)]
-    pub(crate) fn live_regions_unordered(&self) -> impl Iterator<Item = RegionVid> + '_ {
+    pub(crate) fn live_regions_unordered(&self) -> impl Iterator<Item = RegionVid> {
         self.live_regions.as_ref().unwrap().iter().copied()
     }
 
@@ -143,7 +143,7 @@ impl LivenessValues {
     }
 
     /// Returns an iterator of all the points where `region` is live.
-    fn live_points(&self, region: RegionVid) -> impl Iterator<Item = PointIndex> + '_ {
+    fn live_points(&self, region: RegionVid) -> impl Iterator<Item = PointIndex> {
         let Some(points) = &self.points else {
             unreachable!(
                 "Should be using LivenessValues::with_specific_points to ask whether live at a location"
@@ -340,7 +340,7 @@ impl<N: Idx> RegionValues<N> {
     }
 
     /// Returns the locations contained within a given region `r`.
-    pub(crate) fn locations_outlived_by<'a>(&'a self, r: N) -> impl Iterator<Item = Location> + 'a {
+    pub(crate) fn locations_outlived_by<'a>(&'a self, r: N) -> impl Iterator<Item = Location> {
         self.points.row(r).into_iter().flat_map(move |set| {
             set.iter()
                 .take_while(move |&p| self.location_map.point_in_range(p))
@@ -349,18 +349,15 @@ impl<N: Idx> RegionValues<N> {
     }
 
     /// Returns just the universal regions that are contained in a given region's value.
-    pub(crate) fn universal_regions_outlived_by<'a>(
-        &'a self,
-        r: N,
-    ) -> impl Iterator<Item = RegionVid> + 'a {
+    pub(crate) fn universal_regions_outlived_by(&self, r: N) -> impl Iterator<Item = RegionVid> {
         self.free_regions.row(r).into_iter().flat_map(|set| set.iter())
     }
 
     /// Returns all the elements contained in a given region's value.
-    pub(crate) fn placeholders_contained_in<'a>(
-        &'a self,
+    pub(crate) fn placeholders_contained_in(
+        &self,
         r: N,
-    ) -> impl Iterator<Item = ty::PlaceholderRegion> + 'a {
+    ) -> impl Iterator<Item = ty::PlaceholderRegion> {
         self.placeholders
             .row(r)
             .into_iter()
@@ -369,10 +366,7 @@ impl<N: Idx> RegionValues<N> {
     }
 
     /// Returns all the elements contained in a given region's value.
-    pub(crate) fn elements_contained_in<'a>(
-        &'a self,
-        r: N,
-    ) -> impl Iterator<Item = RegionElement> + 'a {
+    pub(crate) fn elements_contained_in<'a>(&'a self, r: N) -> impl Iterator<Item = RegionElement> {
         let points_iter = self.locations_outlived_by(r).map(RegionElement::Location);
 
         let free_regions_iter =

compiler/rustc_borrowck/src/type_check/free_region_relations.rs

@@ -172,7 +172,7 @@ impl UniversalRegionRelations<'_> {
     }
 
     /// Returns the _non-transitive_ set of known `outlives` constraints between free regions.
-    pub(crate) fn known_outlives(&self) -> impl Iterator<Item = (RegionVid, RegionVid)> + '_ {
+    pub(crate) fn known_outlives(&self) -> impl Iterator<Item = (RegionVid, RegionVid)> {
         self.outlives.base_edges()
     }
 }

compiler/rustc_borrowck/src/type_check/liveness/local_use_map.rs

@@ -54,7 +54,7 @@ rustc_index::newtype_index! {
 fn appearances_iter(
     first: Option<AppearanceIndex>,
     appearances: &Appearances,
-) -> impl Iterator<Item = AppearanceIndex> + '_ {
+) -> impl Iterator<Item = AppearanceIndex> {
     AppearancesIter { appearances, current: first }
 }
 
@@ -107,17 +107,17 @@ impl LocalUseMap {
         local_use_map
     }
 
-    pub(crate) fn defs(&self, local: Local) -> impl Iterator<Item = PointIndex> + '_ {
+    pub(crate) fn defs(&self, local: Local) -> impl Iterator<Item = PointIndex> {
         appearances_iter(self.first_def_at[local], &self.appearances)
             .map(move |aa| self.appearances[aa].point_index)
     }
 
-    pub(crate) fn uses(&self, local: Local) -> impl Iterator<Item = PointIndex> + '_ {
+    pub(crate) fn uses(&self, local: Local) -> impl Iterator<Item = PointIndex> {
         appearances_iter(self.first_use_at[local], &self.appearances)
             .map(move |aa| self.appearances[aa].point_index)
     }
 
-    pub(crate) fn drops(&self, local: Local) -> impl Iterator<Item = PointIndex> + '_ {
+    pub(crate) fn drops(&self, local: Local) -> impl Iterator<Item = PointIndex> {
         appearances_iter(self.first_drop_at[local], &self.appearances)
             .map(move |aa| self.appearances[aa].point_index)
     }

compiler/rustc_borrowck/src/universal_regions.rs

@@ -308,7 +308,7 @@ impl<'tcx> UniversalRegions<'tcx> {
 
     /// Returns an iterator over all the RegionVids corresponding to
     /// universally quantified free regions.
-    pub(crate) fn universal_regions_iter(&self) -> impl Iterator<Item = RegionVid> + use<> {
+    pub(crate) fn universal_regions_iter(&self) -> impl Iterator<Item = RegionVid> + 'static {
         (FIRST_GLOBAL_INDEX..self.num_universals).map(RegionVid::from_usize)
     }
 
@@ -332,9 +332,9 @@ impl<'tcx> UniversalRegions<'tcx> {
     }
 
     /// Gets an iterator over all the early-bound regions that have names.
-    pub(crate) fn named_universal_regions_iter<'s>(
-        &'s self,
-    ) -> impl Iterator<Item = (ty::Region<'tcx>, ty::RegionVid)> + 's {
+    pub(crate) fn named_universal_regions_iter(
+        &self,
+    ) -> impl Iterator<Item = (ty::Region<'tcx>, ty::RegionVid)> {
         self.indices.indices.iter().map(|(&r, &v)| (r, v))
     }
 

compiler/rustc_const_eval/src/interpret/intern.rs

@@ -61,8 +61,8 @@ impl HasStaticRootDefId for const_eval::CompileTimeMachine<'_> {
 /// already mutable (as a sanity check).
 ///
 /// Returns an iterator over all relocations referred to by this allocation.
-fn intern_shallow<'rt, 'tcx, T, M: CompileTimeMachine<'tcx, T>>(
-    ecx: &'rt mut InterpCx<'tcx, M>,
+fn intern_shallow<'tcx, T, M: CompileTimeMachine<'tcx, T>>(
+    ecx: &mut InterpCx<'tcx, M>,
     alloc_id: AllocId,
     mutability: Mutability,
 ) -> Result<impl Iterator<Item = CtfeProvenance> + 'tcx, ()> {

compiler/rustc_data_structures/src/graph/implementation/mod.rs

@@ -193,11 +193,11 @@ impl<N: Debug, E: Debug> Graph<N, E> {
         AdjacentEdges { graph: self, direction, next: first_edge }
     }
 
-    pub fn successor_nodes(&self, source: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
+    pub fn successor_nodes(&self, source: NodeIndex) -> impl Iterator<Item = NodeIndex> {
         self.outgoing_edges(source).targets()
     }
 
-    pub fn predecessor_nodes(&self, target: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
+    pub fn predecessor_nodes(&self, target: NodeIndex) -> impl Iterator<Item = NodeIndex> {
         self.incoming_edges(target).sources()
     }
 
@@ -255,11 +255,11 @@ pub struct AdjacentEdges<'g, N, E> {
 }
 
 impl<'g, N: Debug, E: Debug> AdjacentEdges<'g, N, E> {
-    fn targets(self) -> impl Iterator<Item = NodeIndex> + 'g {
+    fn targets(self) -> impl Iterator<Item = NodeIndex> {
         self.map(|(_, edge)| edge.target)
     }
 
-    fn sources(self) -> impl Iterator<Item = NodeIndex> + 'g {
+    fn sources(self) -> impl Iterator<Item = NodeIndex> {
         self.map(|(_, edge)| edge.source)
     }
 }

compiler/rustc_data_structures/src/graph/scc/mod.rs

@@ -133,7 +133,7 @@ impl<N: Idx, S: Idx + Ord, A: Annotation> Sccs<N, S, A> {
     /// meaning that if `S1 -> S2`, we will visit `S2` first and `S1` after.
     /// This is convenient when the edges represent dependencies: when you visit
     /// `S1`, the value for `S2` will already have been computed.
-    pub fn all_sccs(&self) -> impl Iterator<Item = S> + use<N, S, A> {
+    pub fn all_sccs(&self) -> impl Iterator<Item = S> + 'static {
         (0..self.scc_data.len()).map(S::new)
     }
 

compiler/rustc_data_structures/src/sorted_map/index_map.rs

@@ -84,7 +84,7 @@ impl<I: Idx, K: Ord, V> SortedIndexMultiMap<I, K, V> {
     /// If there are multiple items that are equivalent to `key`, they will be yielded in
     /// insertion order.
     #[inline]
-    pub fn get_by_key(&self, key: K) -> impl Iterator<Item = &V> + '_ {
+    pub fn get_by_key(&self, key: K) -> impl Iterator<Item = &V> {
         self.get_by_key_enumerated(key).map(|(_, v)| v)
     }
 
@@ -94,7 +94,7 @@ impl<I: Idx, K: Ord, V> SortedIndexMultiMap<I, K, V> {
     /// If there are multiple items that are equivalent to `key`, they will be yielded in
     /// insertion order.
     #[inline]
-    pub fn get_by_key_enumerated(&self, key: K) -> impl Iterator<Item = (I, &V)> + '_ {
+    pub fn get_by_key_enumerated(&self, key: K) -> impl Iterator<Item = (I, &V)> {
         let lower_bound = self.idx_sorted_by_item_key.partition_point(|&i| self.items[i].0 < key);
         self.idx_sorted_by_item_key[lower_bound..].iter().map_while(move |&i| {
             let (k, v) = &self.items[i];

compiler/rustc_data_structures/src/sso/map.rs

@@ -165,7 +165,7 @@ impl<K, V> SsoHashMap<K, V> {
 
     /// Clears the map, returning all key-value pairs as an iterator. Keeps the
     /// allocated memory for reuse.
-    pub fn drain(&mut self) -> impl Iterator<Item = (K, V)> + '_ {
+    pub fn drain(&mut self) -> impl Iterator<Item = (K, V)> {
         match self {
             SsoHashMap::Array(array) => Either::Left(array.drain(..)),
             SsoHashMap::Map(map) => Either::Right(map.drain()),

compiler/rustc_data_structures/src/sso/set.rs

@@ -80,7 +80,7 @@ impl<T> SsoHashSet<T> {
 
     /// Clears the set, returning all elements in an iterator.
     #[inline]
-    pub fn drain(&mut self) -> impl Iterator<Item = T> + '_ {
+    pub fn drain(&mut self) -> impl Iterator<Item = T> {
         self.map.drain().map(entry_to_key)
     }
 }