Rollup merge of #101881 - TaKO8Ki:remove-unused-struct-field, r=sanxiyn

Remove an unused struct field `late_bound`

compiler/rustc_middle/src/middle/resolve_lifetime.rs

@@ -2,7 +2,7 @@
 
 use crate::ty;
 
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::ItemLocalId;
 use rustc_macros::HashStable;
@@ -51,10 +51,5 @@ pub struct ResolveLifetimes {
     /// `Region` describing how that region is bound
     pub defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>,
 
-    /// Set of lifetime def ids that are late-bound; a region can
-    /// be late-bound if (a) it does NOT appear in a where-clause and
-    /// (b) it DOES appear in the arguments.
-    pub late_bound: FxHashMap<LocalDefId, FxHashSet<LocalDefId>>,
-
     pub late_bound_vars: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>>,
 }