Greatly simplify lifetime captures in edition 2024

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -10,7 +10,6 @@
 use std::fmt::Debug;
 use std::iter;
 
-use rustc_data_structures::captures::Captures;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::mir::ConstraintCategory;
@@ -541,13 +540,13 @@ impl<'tcx> InferCtxt<'tcx> {
 
     /// Converts the region constraints resulting from a query into an
     /// iterator of obligations.
-    fn query_outlives_constraints_into_obligations<'a>(
-        &'a self,
-        cause: &'a ObligationCause<'tcx>,
+    fn query_outlives_constraints_into_obligations(
+        &self,
+        cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-        uninstantiated_region_constraints: &'a [QueryOutlivesConstraint<'tcx>],
-        result_args: &'a CanonicalVarValues<'tcx>,
-    ) -> impl Iterator<Item = PredicateObligation<'tcx>> + 'a + Captures<'tcx> {
+        uninstantiated_region_constraints: &[QueryOutlivesConstraint<'tcx>],
+        result_args: &CanonicalVarValues<'tcx>,
+    ) -> impl Iterator<Item = PredicateObligation<'tcx>> {
         uninstantiated_region_constraints.iter().map(move |&constraint| {
             let predicate = instantiate_value(self.tcx, result_args, constraint);
             self.query_outlives_constraint_to_obligation(predicate, cause.clone(), param_env)

compiler/rustc_infer/src/infer/free_regions.rs

@@ -38,7 +38,7 @@ pub struct FreeRegionMap<'tcx> {
 }
 
 impl<'tcx> FreeRegionMap<'tcx> {
-    pub fn elements(&self) -> impl Iterator<Item = Region<'tcx>> + '_ {
+    pub fn elements(&self) -> impl Iterator<Item = Region<'tcx>> {
         self.relation.elements().copied()
     }
 

compiler/rustc_infer/src/infer/mod.rs

@@ -15,7 +15,6 @@ use region_constraints::{
 };
 pub use relate::StructurallyRelateAliases;
 pub use relate::combine::PredicateEmittingRelation;
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::undo_log::{Rollback, UndoLogs};
 use rustc_data_structures::unify as ut;
@@ -233,7 +232,7 @@ impl<'tcx> InferCtxtInner<'tcx> {
     // while looping through this.
     pub fn iter_opaque_types(
         &self,
-    ) -> impl Iterator<Item = (ty::OpaqueTypeKey<'tcx>, ty::OpaqueHiddenType<'tcx>)> + '_ {
+    ) -> impl Iterator<Item = (ty::OpaqueTypeKey<'tcx>, ty::OpaqueHiddenType<'tcx>)> {
         self.opaque_type_storage.opaque_types.iter().map(|(&k, &v)| (k, v))
     }
 }
@@ -1295,9 +1294,7 @@ impl<'tcx> InferCtxt<'tcx> {
     /// The returned function is used in a fast path. If it returns `true` the variable is
     /// unchanged, `false` indicates that the status is unknown.
     #[inline]
-    pub fn is_ty_infer_var_definitely_unchanged<'a>(
-        &'a self,
-    ) -> (impl Fn(TyOrConstInferVar) -> bool + Captures<'tcx> + 'a) {
+    pub fn is_ty_infer_var_definitely_unchanged(&self) -> impl Fn(TyOrConstInferVar) -> bool {
         // This hoists the borrow/release out of the loop body.
         let inner = self.inner.try_borrow();
 

compiler/rustc_infer/src/infer/outlives/mod.rs

@@ -20,7 +20,7 @@ pub(crate) mod verify;
 #[instrument(level = "debug", skip(param_env), ret)]
 pub fn explicit_outlives_bounds<'tcx>(
     param_env: ty::ParamEnv<'tcx>,
-) -> impl Iterator<Item = OutlivesBound<'tcx>> + 'tcx {
+) -> impl Iterator<Item = OutlivesBound<'tcx>> {
     param_env
         .caller_bounds()
         .into_iter()