Revert "Only consider places with the same local in each_borrow_involving_path."

This reverts commit 372366d.

Author: compiler-errors

compiler/rustc_borrowck/src/invalidation.rs

@@ -353,14 +353,15 @@ impl<'cx, 'tcx> InvalidationGenerator<'cx, 'tcx> {
         let tcx = self.tcx;
         let body = self.body;
         let borrow_set = self.borrow_set;
+        let indices = self.borrow_set.indices();
         each_borrow_involving_path(
             self,
             tcx,
             body,
             location,
             (sd, place),
             borrow_set,
-            |_| true,
+            indices,
             |this, borrow_index, borrow| {
                 match (rw, borrow.kind) {
                     // Obviously an activation is compatible with its own

compiler/rustc_borrowck/src/lib.rs

@@ -23,7 +23,7 @@ use rustc_errors::{Diagnostic, DiagnosticBuilder, DiagnosticMessage, Subdiagnost
 use rustc_fluent_macro::fluent_messages;
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
-use rustc_index::bit_set::{BitSet, ChunkedBitSet};
+use rustc_index::bit_set::ChunkedBitSet;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_infer::infer::{
     InferCtxt, NllRegionVariableOrigin, RegionVariableOrigin, TyCtxtInferExt,
@@ -42,6 +42,7 @@ use rustc_session::lint::builtin::UNUSED_MUT;
 use rustc_span::{Span, Symbol};
 use rustc_target::abi::FieldIdx;
 
+use either::Either;
 use smallvec::SmallVec;
 use std::cell::RefCell;
 use std::collections::BTreeMap;
@@ -1034,16 +1035,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let borrow_set = self.borrow_set.clone();
 
         // Use polonius output if it has been enabled.
-        let mut polonius_output;
-        let borrows_in_scope = if let Some(polonius) = &self.polonius_output {
+        let polonius_output = self.polonius_output.clone();
+        let borrows_in_scope = if let Some(polonius) = &polonius_output {
             let location = self.location_table.start_index(location);
-            polonius_output = BitSet::new_empty(borrow_set.len());
-            for &idx in polonius.errors_at(location) {
-                polonius_output.insert(idx);
-            }
-            &polonius_output
+            Either::Left(polonius.errors_at(location).iter().copied())
         } else {
-            &flow_state.borrows
+            Either::Right(flow_state.borrows.iter())
         };
 
         each_borrow_involving_path(
@@ -1053,7 +1050,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             location,
             (sd, place_span.0),
             &borrow_set,
-            |borrow_index| borrows_in_scope.contains(borrow_index),
+            borrows_in_scope,
             |this, borrow_index, borrow| match (rw, borrow.kind) {
                 // Obviously an activation is compatible with its own
                 // reservation (or even prior activating uses of same

compiler/rustc_borrowck/src/path_utils.rs

@@ -33,24 +33,20 @@ pub(super) fn each_borrow_involving_path<'tcx, F, I, S>(
     _location: Location,
     access_place: (AccessDepth, Place<'tcx>),
     borrow_set: &BorrowSet<'tcx>,
-    is_candidate: I,
+    candidates: I,
     mut op: F,
 ) where
     F: FnMut(&mut S, BorrowIndex, &BorrowData<'tcx>) -> Control,
-    I: Fn(BorrowIndex) -> bool,
+    I: Iterator<Item = BorrowIndex>,
 {
     let (access, place) = access_place;
 
-    // The number of candidates can be large, but borrows for different locals cannot conflict with
-    // each other, so we restrict the working set a priori.
-    let Some(borrows_for_place_base) = borrow_set.local_map.get(&place.local) else { return };
+    // FIXME: analogous code in check_loans first maps `place` to
+    // its base_path.
 
     // check for loan restricting path P being used. Accounts for
     // borrows of P, P.a.b, etc.
-    for &i in borrows_for_place_base {
-        if !is_candidate(i) {
-            continue;
-        }
+    for i in candidates {
         let borrowed = &borrow_set[i];
 
         if places_conflict::borrow_conflicts_with_place(