Merging upstream version 1.70.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 177 insertions, 157 deletions

diff --git a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
index 68205fa45..84f75caa6 100644
--- a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
@@ -181,8 +181,8 @@ trait TypeOpInfo<'tcx> {
         };
 
         let placeholder_region = tcx.mk_re_placeholder(ty::Placeholder {
-            name: placeholder.name,
             universe: adjusted_universe.into(),
+            bound: placeholder.bound,
         });
 
         let error_region =
@@ -191,8 +191,8 @@ trait TypeOpInfo<'tcx> {
                     error_placeholder.universe.as_u32().checked_sub(base_universe.as_u32());
                 adjusted_universe.map(|adjusted| {
                     tcx.mk_re_placeholder(ty::Placeholder {
-                        name: error_placeholder.name,
                         universe: adjusted.into(),
+                        bound: error_placeholder.bound,
                     })
                 })
             } else {
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index cb97699d7..75a3dd0c0 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -1,7 +1,7 @@
 use either::Either;
 use rustc_const_eval::util::CallKind;
 use rustc_data_structures::captures::Captures;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::{
     struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
 };
@@ -24,6 +24,7 @@ use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::{BytePos, Span, Symbol};
 use rustc_trait_selection::infer::InferCtxtExt;
+use rustc_trait_selection::traits::ObligationCtxt;
 
 use crate::borrow_set::TwoPhaseActivation;
 use crate::borrowck_errors;
@@ -173,7 +174,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
             let mut is_loop_move = false;
             let mut in_pattern = false;
-            let mut seen_spans = FxHashSet::default();
+            let mut seen_spans = FxIndexSet::default();
 
             for move_site in &move_site_vec {
                 let move_out = self.move_data.moves[(*move_site).moi];
@@ -760,20 +761,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         else { return; };
         // Try to find predicates on *generic params* that would allow copying `ty`
         let infcx = tcx.infer_ctxt().build();
-        let copy_did = infcx.tcx.require_lang_item(LangItem::Copy, Some(span));
-        let cause = ObligationCause::new(
-            span,
-            self.mir_def_id(),
-            rustc_infer::traits::ObligationCauseCode::MiscObligation,
-        );
-        let errors = rustc_trait_selection::traits::fully_solve_bound(
-            &infcx,
-            cause,
-            self.param_env,
-            // Erase any region vids from the type, which may not be resolved
-            infcx.tcx.erase_regions(ty),
-            copy_did,
-        );
+        let ocx = ObligationCtxt::new(&infcx);
+        let copy_did = tcx.require_lang_item(LangItem::Copy, Some(span));
+        let cause = ObligationCause::misc(span, self.mir_def_id());
+
+        ocx.register_bound(cause, self.param_env, infcx.tcx.erase_regions(ty), copy_did);
+        let errors = ocx.select_all_or_error();
 
         // Only emit suggestion if all required predicates are on generic
         let predicates: Result<Vec<_>, _> = errors
@@ -1467,6 +1460,32 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// Reports StorageDeadOrDrop of `place` conflicts with `borrow`.
     ///
+    /// Depending on the origin of the StorageDeadOrDrop, this may be
+    /// reported as either a drop or an illegal mutation of a borrowed value.
+    /// The latter is preferred when the this is a drop triggered by a
+    /// reassignment, as it's more user friendly to report a problem with the
+    /// explicit assignment than the implicit drop.
+    #[instrument(level = "debug", skip(self))]
+    pub(crate) fn report_storage_dead_or_drop_of_borrowed(
+        &mut self,
+        location: Location,
+        place_span: (Place<'tcx>, Span),
+        borrow: &BorrowData<'tcx>,
+    ) {
+        // It's sufficient to check the last desugaring as Replace is the last
+        // one to be applied.
+        if let Some(DesugaringKind::Replace) = place_span.1.desugaring_kind() {
+            self.report_illegal_mutation_of_borrowed(location, place_span, borrow)
+        } else {
+            self.report_borrowed_value_does_not_live_long_enough(
+                location,
+                borrow,
+                place_span,
+                Some(WriteKind::StorageDeadOrDrop),
+            )
+        }
+    }
+
     /// This means that some data referenced by `borrow` needs to live
     /// past the point where the StorageDeadOrDrop of `place` occurs.
     /// This is usually interpreted as meaning that `place` has too
@@ -1959,16 +1978,18 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let (place_desc, note) = if let Some(place_desc) = opt_place_desc {
             let local_kind = if let Some(local) = borrow.borrowed_place.as_local() {
                 match self.body.local_kind(local) {
-                    LocalKind::ReturnPointer | LocalKind::Temp => {
-                        bug!("temporary or return pointer with a name")
+                    LocalKind::Temp if self.body.local_decls[local].is_user_variable() => {
+                        "local variable "
                     }
-                    LocalKind::Var => "local variable ",
                     LocalKind::Arg
                         if !self.upvars.is_empty() && local == ty::CAPTURE_STRUCT_LOCAL =>
                     {
                         "variable captured by `move` "
                     }
                     LocalKind::Arg => "function parameter ",
+                    LocalKind::ReturnPointer | LocalKind::Temp => {
+                        bug!("temporary or return pointer with a name")
+                    }
                 }
             } else {
                 "local data "
@@ -1982,16 +2003,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 self.prefixes(borrow.borrowed_place.as_ref(), PrefixSet::All).last().unwrap();
             let local = root_place.local;
             match self.body.local_kind(local) {
-                LocalKind::ReturnPointer | LocalKind::Temp => {
-                    ("temporary value".to_string(), "temporary value created here".to_string())
-                }
                 LocalKind::Arg => (
                     "function parameter".to_string(),
                     "function parameter borrowed here".to_string(),
                 ),
-                LocalKind::Var => {
+                LocalKind::Temp if self.body.local_decls[local].is_user_variable() => {
                     ("local binding".to_string(), "local binding introduced here".to_string())
                 }
+                LocalKind::ReturnPointer | LocalKind::Temp => {
+                    ("temporary value".to_string(), "temporary value created here".to_string())
+                }
             }
         };
 
@@ -2197,8 +2218,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
         }
 
-        let mut visited = FxHashSet::default();
-        let mut move_locations = FxHashSet::default();
+        let mut visited = FxIndexSet::default();
+        let mut move_locations = FxIndexSet::default();
         let mut reinits = vec![];
         let mut result = vec![];
 
@@ -2325,7 +2346,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let reinits_reachable = reinits
             .into_iter()
             .filter(|reinit| {
-                let mut visited = FxHashSet::default();
+                let mut visited = FxIndexSet::default();
                 let mut stack = vec![*reinit];
                 while let Some(location) = stack.pop() {
                     if !visited.insert(location) {
@@ -2456,15 +2477,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let (place_description, assigned_span) = match local_decl {
             Some(LocalDecl {
                 local_info:
-                    Some(box LocalInfo::User(
-                        ClearCrossCrate::Clear
-                        | ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
+                    ClearCrossCrate::Set(
+                        box LocalInfo::User(BindingForm::Var(VarBindingForm {
                             opt_match_place: None,
                             ..
-                        })),
-                    ))
-                    | Some(box LocalInfo::StaticRef { .. })
-                    | None,
+                        }))
+                        | box LocalInfo::StaticRef { .. }
+                        | box LocalInfo::Boring,
+                    ),
                 ..
             })
             | None => (self.describe_any_place(place.as_ref()), assigned_span),
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 19855075c..8860395e7 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -3,11 +3,11 @@
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir as hir;
 use rustc_hir::intravisit::Visitor;
-use rustc_index::vec::IndexVec;
+use rustc_index::vec::IndexSlice;
 use rustc_infer::infer::NllRegionVariableOrigin;
 use rustc_middle::mir::{
-    Body, CastKind, ConstraintCategory, FakeReadCause, Local, Location, Operand, Place, Rvalue,
-    Statement, StatementKind, TerminatorKind,
+    Body, CastKind, ConstraintCategory, FakeReadCause, Local, LocalInfo, Location, Operand, Place,
+    Rvalue, Statement, StatementKind, TerminatorKind,
 };
 use rustc_middle::ty::adjustment::PointerCast;
 use rustc_middle::ty::{self, RegionVid, TyCtxt};
@@ -60,7 +60,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
         &self,
         tcx: TyCtxt<'tcx>,
         body: &Body<'tcx>,
-        local_names: &IndexVec<Local, Option<Symbol>>,
+        local_names: &IndexSlice<Local, Option<Symbol>>,
         err: &mut Diagnostic,
         borrow_desc: &str,
         borrow_span: Option<Span>,
@@ -220,7 +220,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                         );
                         err.span_label(body.source_info(drop_loc).span, message);
 
-                        if let Some(info) = &local_decl.is_block_tail {
+                        if let LocalInfo::BlockTailTemp(info) = local_decl.local_info() {
                             if info.tail_result_is_ignored {
                                 // #85581: If the first mutable borrow's scope contains
                                 // the second borrow, this suggestion isn't helpful.
diff --git a/compiler/rustc_borrowck/src/diagnostics/find_use.rs b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
index 15f42e26c..2495613fe 100644
--- a/compiler/rustc_borrowck/src/diagnostics/find_use.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
@@ -6,12 +6,11 @@ use std::rc::Rc;
 
 use crate::{
     def_use::{self, DefUse},
-    nll::ToRegionVid,
     region_infer::{Cause, RegionInferenceContext},
 };
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_middle::mir::visit::{MirVisitable, PlaceContext, Visitor};
-use rustc_middle::mir::{Body, Local, Location};
+use rustc_middle::mir::{self, Body, Local, Location};
 use rustc_middle::ty::{RegionVid, TyCtxt};
 
 pub(crate) fn find<'tcx>(
@@ -37,7 +36,7 @@ struct UseFinder<'cx, 'tcx> {
 impl<'cx, 'tcx> UseFinder<'cx, 'tcx> {
     fn find(&mut self) -> Option<Cause> {
         let mut queue = VecDeque::new();
-        let mut visited = FxHashSet::default();
+        let mut visited = FxIndexSet::default();
 
         queue.push_back(self.start_point);
         while let Some(p) = queue.pop_front() {
@@ -70,7 +69,10 @@ impl<'cx, 'tcx> UseFinder<'cx, 'tcx> {
                             block_data
                                 .terminator()
                                 .successors()
-                                .filter(|&bb| Some(&Some(bb)) != block_data.terminator().unwind())
+                                .filter(|&bb| {
+                                    Some(&mir::UnwindAction::Cleanup(bb))
+                                        != block_data.terminator().unwind()
+                                })
                                 .map(|bb| Location { statement_index: 0, block: bb }),
                         );
                     }
@@ -114,7 +116,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for DefUseVisitor<'cx, 'tcx> {
 
         let mut found_it = false;
         self.tcx.for_each_free_region(&local_ty, |r| {
-            if r.to_region_vid() == self.region_vid {
+            if r.as_var() == self.region_vid {
                 found_it = true;
             }
         });
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index a99fd594a..110354a20 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -6,18 +6,19 @@ use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, Namespace};
 use rustc_hir::GeneratorKind;
+use rustc_index::vec::IndexSlice;
 use rustc_infer::infer::{LateBoundRegionConversionTime, TyCtxtInferExt};
 use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::mir::{
-    AggregateKind, Constant, FakeReadCause, Field, Local, LocalInfo, LocalKind, Location, Operand,
-    Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
+    AggregateKind, Constant, FakeReadCause, Local, LocalInfo, LocalKind, Location, Operand, Place,
+    PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
 };
 use rustc_middle::ty::print::Print;
-use rustc_middle::ty::{self, DefIdTree, Instance, Ty, TyCtxt};
+use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{
     type_known_to_meet_bound_modulo_regions, Obligation, ObligationCause,
@@ -196,10 +197,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         if self.body.local_decls[local].is_ref_for_guard() {
                             continue;
                         }
-                        if let Some(box LocalInfo::StaticRef { def_id, .. }) =
-                            &self.body.local_decls[local].local_info
+                        if let LocalInfo::StaticRef { def_id, .. } =
+                            *self.body.local_decls[local].local_info()
                         {
-                            buf.push_str(self.infcx.tcx.item_name(*def_id).as_str());
+                            buf.push_str(self.infcx.tcx.item_name(def_id).as_str());
                             ok = Ok(());
                             continue;
                         }
@@ -302,7 +303,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn describe_field(
         &self,
         place: PlaceRef<'tcx>,
-        field: Field,
+        field: FieldIdx,
         including_tuple_field: IncludingTupleField,
     ) -> Option<String> {
         let place_ty = match place {
@@ -331,7 +332,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn describe_field_from_ty(
         &self,
         ty: Ty<'_>,
-        field: Field,
+        field: FieldIdx,
         variant_index: Option<VariantIdx>,
         including_tuple_field: IncludingTupleField,
     ) -> Option<String> {
@@ -350,7 +351,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     if !including_tuple_field.0 && variant.ctor_kind() == Some(CtorKind::Fn) {
                         return None;
                     }
-                    Some(variant.fields[field.index()].name.to_string())
+                    Some(variant.fields[field].name.to_string())
                 }
                 ty::Tuple(_) => Some(field.index().to_string()),
                 ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
@@ -466,9 +467,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         if let ty::Ref(region, ..) = ty.kind() {
             match **region {
                 ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
-                | ty::RePlaceholder(ty::PlaceholderRegion { name: br, .. }) => {
-                    printer.region_highlight_mode.highlighting_bound_region(br, counter)
-                }
+                | ty::RePlaceholder(ty::PlaceholderRegion {
+                    bound: ty::BoundRegion { kind: br, .. },
+                    ..
+                }) => printer.region_highlight_mode.highlighting_bound_region(br, counter),
                 _ => {}
             }
         }
@@ -484,9 +486,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let region = if let ty::Ref(region, ..) = ty.kind() {
             match **region {
                 ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
-                | ty::RePlaceholder(ty::PlaceholderRegion { name: br, .. }) => {
-                    printer.region_highlight_mode.highlighting_bound_region(br, counter)
-                }
+                | ty::RePlaceholder(ty::PlaceholderRegion {
+                    bound: ty::BoundRegion { kind: br, .. },
+                    ..
+                }) => printer.region_highlight_mode.highlighting_bound_region(br, counter),
                 _ => {}
             }
             region
@@ -825,7 +828,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     debug!("move_spans: def_id={:?} place={:?}", closure_def_id, place);
                     let places = &[Operand::Move(place)];
                     if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
-                        self.closure_span(closure_def_id, moved_place, places)
+                        self.closure_span(closure_def_id, moved_place, IndexSlice::from_raw(places))
                     {
                         return ClosureUse {
                             generator_kind,
@@ -925,7 +928,20 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             return OtherUse(use_span);
         }
 
-        for stmt in &self.body[location.block].statements[location.statement_index + 1..] {
+        // drop and replace might have moved the assignment to the next block
+        let maybe_additional_statement =
+            if let TerminatorKind::Drop { target: drop_target, .. } =
+                self.body[location.block].terminator().kind
+            {
+                self.body[drop_target].statements.first()
+            } else {
+                None
+            };
+
+        let statements =
+            self.body[location.block].statements[location.statement_index + 1..].iter();
+
+        for stmt in statements.chain(maybe_additional_statement) {
             if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind {
                 let (&def_id, is_generator) = match kind {
                     box AggregateKind::Closure(def_id, _) => (def_id, false),
@@ -962,7 +978,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         def_id: LocalDefId,
         target_place: PlaceRef<'tcx>,
-        places: &[Operand<'tcx>],
+        places: &IndexSlice<FieldIdx, Operand<'tcx>>,
     ) -> Option<(Span, Option<GeneratorKind>, Span, Span)> {
         debug!(
             "closure_span: def_id={:?} target_place={:?} places={:?}",
@@ -1065,7 +1081,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     self.param_env,
                                     tcx.mk_imm_ref(tcx.lifetimes.re_erased, tcx.erase_regions(ty)),
                                     def_id,
-                                    DUMMY_SP,
                                 )
                             }
                             _ => false,
diff --git a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
index 5e4c7292e..3662bec0c 100644
--- a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -102,14 +102,12 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         //
                         // opt_match_place is None for let [mut] x = ... statements,
                         // whether or not the right-hand side is a place expression
-                        if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
-                            VarBindingForm {
-                                opt_match_place: Some((opt_match_place, match_span)),
-                                binding_mode: _,
-                                opt_ty_info: _,
-                                pat_span: _,
-                            },
-                        )))) = local_decl.local_info
+                        if let LocalInfo::User(BindingForm::Var(VarBindingForm {
+                            opt_match_place: Some((opt_match_place, match_span)),
+                            binding_mode: _,
+                            opt_ty_info: _,
+                            pat_span: _,
+                        })) = *local_decl.local_info()
                         {
                             let stmt_source_info = self.body.source_info(location);
                             self.append_binding_error(
@@ -478,9 +476,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let mut suggestions: Vec<(Span, String, String)> = Vec::new();
         for local in binds_to {
             let bind_to = &self.body.local_decls[*local];
-            if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
-                VarBindingForm { pat_span, .. },
-            )))) = bind_to.local_info
+            if let LocalInfo::User(BindingForm::Var(VarBindingForm { pat_span, .. })) =
+                *bind_to.local_info()
             {
                 let Ok(pat_snippet) =
                     self.infcx.tcx.sess.source_map().span_to_snippet(pat_span) else { continue; };
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index 328ac880d..9d9040096 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -7,11 +7,12 @@ use rustc_middle::mir::{Mutability, Place, PlaceRef, ProjectionElem};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{
     hir::place::PlaceBase,
-    mir::{self, BindingForm, ClearCrossCrate, Local, LocalDecl, LocalInfo, LocalKind, Location},
+    mir::{self, BindingForm, Local, LocalDecl, LocalInfo, LocalKind, Location},
 };
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, BytePos, Span};
+use rustc_target::abi::FieldIdx;
 
 use crate::diagnostics::BorrowedContentSource;
 use crate::MirBorrowckCtxt;
@@ -105,8 +106,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     reason = String::new();
                 } else {
                     item_msg = access_place_desc;
-                    let local_info = &self.body.local_decls[local].local_info;
-                    if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
+                    let local_info = self.body.local_decls[local].local_info();
+                    if let LocalInfo::StaticRef { def_id, .. } = *local_info {
                         let static_name = &self.infcx.tcx.item_name(def_id);
                         reason = format!(", as `{static_name}` is an immutable static item");
                     } else {
@@ -120,9 +121,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     && !self.upvars.is_empty()
                 {
                     item_msg = access_place_desc;
-                    debug_assert!(
-                        self.body.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty.is_region_ptr()
-                    );
+                    debug_assert!(self.body.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty.is_ref());
                     debug_assert!(is_closure_or_generator(
                         Place::ty_from(
                             the_place_err.local,
@@ -305,15 +304,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     ..
                 }) = &self.body[location.block].statements.get(location.statement_index)
                 {
-                    match decl.local_info {
-                        Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
-                            mir::VarBindingForm {
-                                binding_mode: ty::BindingMode::BindByValue(Mutability::Not),
-                                opt_ty_info: Some(sp),
-                                opt_match_place: _,
-                                pat_span: _,
-                            },
-                        )))) => {
+                    match *decl.local_info() {
+                        LocalInfo::User(BindingForm::Var(mir::VarBindingForm {
+                            binding_mode: ty::BindingMode::BindByValue(Mutability::Not),
+                            opt_ty_info: Some(sp),
+                            opt_match_place: _,
+                            pat_span: _,
+                        })) => {
                             if suggest {
                                 err.span_note(sp, "the binding is already a mutable borrow");
                             }
@@ -346,10 +343,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     }
                 } else if decl.mutability.is_not() {
                     if matches!(
-                        decl.local_info,
-                        Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(
-                            hir::ImplicitSelfKind::MutRef
-                        ),)))
+                        decl.local_info(),
+                        LocalInfo::User(BindingForm::ImplicitSelf(hir::ImplicitSelfKind::MutRef))
                     ) {
                         err.note(
                             "as `Self` may be unsized, this call attempts to take `&mut &mut self`",
@@ -474,30 +469,23 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             {
                 let local_decl = &self.body.local_decls[local];
 
-                let (pointer_sigil, pointer_desc) = if local_decl.ty.is_region_ptr() {
-                    ("&", "reference")
-                } else {
-                    ("*const", "pointer")
-                };
+                let (pointer_sigil, pointer_desc) =
+                    if local_decl.ty.is_ref() { ("&", "reference") } else { ("*const", "pointer") };
 
                 match self.local_names[local] {
                     Some(name) if !local_decl.from_compiler_desugaring() => {
-                        let label = match local_decl.local_info.as_deref().unwrap() {
-                            LocalInfo::User(ClearCrossCrate::Set(
-                                mir::BindingForm::ImplicitSelf(_),
-                            )) => {
+                        let label = match *local_decl.local_info() {
+                            LocalInfo::User(mir::BindingForm::ImplicitSelf(_)) => {
                                 let (span, suggestion) =
                                     suggest_ampmut_self(self.infcx.tcx, local_decl);
                                 Some((true, span, suggestion))
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
-                                mir::VarBindingForm {
-                                    binding_mode: ty::BindingMode::BindByValue(_),
-                                    opt_ty_info,
-                                    ..
-                                },
-                            ))) => {
+                            LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
+                                binding_mode: ty::BindingMode::BindByValue(_),
+                                opt_ty_info,
+                                ..
+                            })) => {
                                 // check if the RHS is from desugaring
                                 let opt_assignment_rhs_span =
                                     self.body.find_assignments(local).first().map(|&location| {
@@ -534,16 +522,15 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                                 self.infcx.tcx,
                                                 local_decl,
                                                 opt_assignment_rhs_span,
-                                                *opt_ty_info,
+                                                opt_ty_info,
                                             )
                                         } else {
-                                            match local_decl.local_info.as_deref() {
-                                                Some(LocalInfo::User(ClearCrossCrate::Set(
-                                                    mir::BindingForm::Var(mir::VarBindingForm {
-                                                        opt_ty_info: None,
-                                                        ..
-                                                    }),
-                                                ))) => {
+                                            match local_decl.local_info() {
+                                                LocalInfo::User(mir::BindingForm::Var(
+                                                    mir::VarBindingForm {
+                                                        opt_ty_info: None, ..
+                                                    },
+                                                )) => {
                                                     let (span, sugg) = suggest_ampmut_self(
                                                         self.infcx.tcx,
                                                         local_decl,
@@ -555,7 +542,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                                     self.infcx.tcx,
                                                     local_decl,
                                                     opt_assignment_rhs_span,
-                                                    *opt_ty_info,
+                                                    opt_ty_info,
                                                 ),
                                             }
                                         };
@@ -564,21 +551,15 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                 }
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
-                                mir::VarBindingForm {
-                                    binding_mode: ty::BindingMode::BindByReference(_),
-                                    ..
-                                },
-                            ))) => {
+                            LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
+                                binding_mode: ty::BindingMode::BindByReference(_),
+                                ..
+                            })) => {
                                 let pattern_span = local_decl.source_info.span;
                                 suggest_ref_mut(self.infcx.tcx, pattern_span)
                                     .map(|replacement| (true, pattern_span, replacement))
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Clear) => {
-                                bug!("saw cleared local state")
-                            }
-
                             _ => unreachable!(),
                         };
 
@@ -828,7 +809,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             let Some(hir::Node::Item(item)) = node else { return; };
             let hir::ItemKind::Fn(.., body_id) = item.kind else { return; };
             let body = self.infcx.tcx.hir().body(body_id);
-            let mut v = V { assign_span: span, err, ty, suggested: false };
+            let mut assign_span = span;
+            // Drop desugaring is done at MIR build so it's not in the HIR
+            if let Some(DesugaringKind::Replace) = span.desugaring_kind() {
+                assign_span.remove_mark();
+            }
+
+            let mut v = V { assign_span, err, ty, suggested: false };
             v.visit_body(body);
             if !v.suggested {
                 err.help(&format!(
@@ -1145,20 +1132,19 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 pub fn mut_borrow_of_mutable_ref(local_decl: &LocalDecl<'_>, local_name: Option<Symbol>) -> bool {
     debug!("local_info: {:?}, ty.kind(): {:?}", local_decl.local_info, local_decl.ty.kind());
 
-    match local_decl.local_info.as_deref() {
+    match *local_decl.local_info() {
         // Check if mutably borrowing a mutable reference.
-        Some(LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
-            mir::VarBindingForm {
-                binding_mode: ty::BindingMode::BindByValue(Mutability::Not), ..
-            },
-        )))) => matches!(local_decl.ty.kind(), ty::Ref(_, _, hir::Mutability::Mut)),
-        Some(LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::ImplicitSelf(kind)))) => {
+        LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
+            binding_mode: ty::BindingMode::BindByValue(Mutability::Not),
+            ..
+        })) => matches!(local_decl.ty.kind(), ty::Ref(_, _, hir::Mutability::Mut)),
+        LocalInfo::User(mir::BindingForm::ImplicitSelf(kind)) => {
             // Check if the user variable is a `&mut self` and we can therefore
             // suggest removing the `&mut`.
             //
             // Deliberately fall into this case for all implicit self types,
             // so that we don't fall in to the next case with them.
-            *kind == hir::ImplicitSelfKind::MutRef
+            kind == hir::ImplicitSelfKind::MutRef
         }
         _ if Some(kw::SelfLower) == local_name => {
             // Otherwise, check if the name is the `self` keyword - in which case
@@ -1268,7 +1254,7 @@ fn suggest_ampmut<'tcx>(
     (
         suggestability,
         highlight_span,
-        if local_decl.ty.is_region_ptr() {
+        if local_decl.ty.is_ref() {
             format!("&mut {}", ty_mut.ty)
         } else {
             format!("*mut {}", ty_mut.ty)
@@ -1290,7 +1276,7 @@ fn is_closure_or_generator(ty: Ty<'_>) -> bool {
 fn get_mut_span_in_struct_field<'tcx>(
     tcx: TyCtxt<'tcx>,
     ty: Ty<'tcx>,
-    field: mir::Field,
+    field: FieldIdx,
 ) -> Option<Span> {
     // Expect our local to be a reference to a struct of some kind.
     if let ty::Ref(_, ty, _) = ty.kind()
diff --git a/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
index 1eaf0a2f1..d5ece5743 100644
--- a/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
@@ -1,7 +1,7 @@
 //! Contains utilities for generating suggestions for borrowck errors related to unsatisfied
 //! outlives constraints.
 
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::Diagnostic;
 use rustc_middle::ty::RegionVid;
 use smallvec::SmallVec;
@@ -87,7 +87,7 @@ impl OutlivesSuggestionBuilder {
 
         // Keep track of variables that we have already suggested unifying so that we don't print
         // out silly duplicate messages.
-        let mut unified_already = FxHashSet::default();
+        let mut unified_already = FxIndexSet::default();
 
         for (fr, outlived) in &self.constraints_to_add {
             let Some(fr_name) = self.region_vid_to_name(mbcx, *fr) else {
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index ffe82b46c..9fcebeb0a 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -207,7 +207,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             .regioncx
             .placeholders_contained_in(lower_bound)
             .map(|placeholder| {
-                if let Some(id) = placeholder.name.get_id()
+                if let Some(id) = placeholder.bound.kind.get_id()
                     && let Some(placeholder_id) = id.as_local()
                     && let gat_hir_id = hir.local_def_id_to_hir_id(placeholder_id)
                     && let Some(generics_impl) = hir.get_parent(gat_hir_id).generics()
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_name.rs b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
index f6881a2e5..f69c4829a 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
@@ -6,11 +6,11 @@ use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_middle::ty::print::RegionHighlightMode;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, DefIdTree, RegionVid, Ty};
+use rustc_middle::ty::{self, RegionVid, Ty};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 
-use crate::{nll::ToRegionVid, universal_regions::DefiningTy, MirBorrowckCtxt};
+use crate::{universal_regions::DefiningTy, MirBorrowckCtxt};
 
 /// A name for a particular region used in emitting diagnostics. This name could be a generated
 /// name like `'1`, a name used by the user like `'a`, or a name like `'static`.
@@ -497,7 +497,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                 //     &
                 //     - let's call the lifetime of this reference `'1`
                 (ty::Ref(region, referent_ty, _), hir::TyKind::Ref(_lifetime, referent_hir_ty)) => {
-                    if region.to_region_vid() == needle_fr {
+                    if region.as_var() == needle_fr {
                         // Just grab the first character, the `&`.
                         let source_map = self.infcx.tcx.sess.source_map();
                         let ampersand_span = source_map.start_point(hir_ty.span);
@@ -598,7 +598,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
         for (kind, hir_arg) in iter::zip(substs, args.args) {
             match (kind.unpack(), hir_arg) {
                 (GenericArgKind::Lifetime(r), hir::GenericArg::Lifetime(lt)) => {
-                    if r.to_region_vid() == needle_fr {
+                    if r.as_var() == needle_fr {
                         return Some(lt);
                     }
                 }
@@ -666,7 +666,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
 
         let return_ty = self.regioncx.universal_regions().unnormalized_output_ty;
         debug!("give_name_if_anonymous_region_appears_in_output: return_ty = {:?}", return_ty);
-        if !tcx.any_free_region_meets(&return_ty, |r| r.to_region_vid() == fr) {
+        if !tcx.any_free_region_meets(&return_ty, |r| r.as_var() == fr) {
             return None;
         }
 
@@ -803,7 +803,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
 
         let tcx = self.infcx.tcx;
 
-        if !tcx.any_free_region_meets(&yield_ty, |r| r.to_region_vid() == fr) {
+        if !tcx.any_free_region_meets(&yield_ty, |r| r.as_var() == fr) {
             return None;
         }
 
diff --git a/compiler/rustc_borrowck/src/diagnostics/var_name.rs b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
index ada3310d8..376415e3d 100644
--- a/compiler/rustc_borrowck/src/diagnostics/var_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
@@ -1,9 +1,9 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
+use crate::region_infer::RegionInferenceContext;
 use crate::Upvar;
-use crate::{nll::ToRegionVid, region_infer::RegionInferenceContext};
-use rustc_index::vec::{Idx, IndexVec};
+use rustc_index::vec::{Idx, IndexSlice};
 use rustc_middle::mir::{Body, Local};
 use rustc_middle::ty::{RegionVid, TyCtxt};
 use rustc_span::source_map::Span;
@@ -14,7 +14,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         &self,
         tcx: TyCtxt<'tcx>,
         body: &Body<'tcx>,
-        local_names: &IndexVec<Local, Option<Symbol>>,
+        local_names: &IndexSlice<Local, Option<Symbol>>,
         upvars: &[Upvar<'tcx>],
         fr: RegionVid,
     ) -> Option<(Option<Symbol>, Span)> {
@@ -46,7 +46,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             self.universal_regions().defining_ty.upvar_tys().position(|upvar_ty| {
                 debug!("get_upvar_index_for_region: upvar_ty={upvar_ty:?}");
                 tcx.any_free_region_meets(&upvar_ty, |r| {
-                    let r = r.to_region_vid();
+                    let r = r.as_var();
                     debug!("get_upvar_index_for_region: r={r:?} fr={fr:?}");
                     r == fr
                 })
@@ -96,7 +96,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             self.universal_regions().unnormalized_input_tys.iter().skip(implicit_inputs).position(
                 |arg_ty| {
                     debug!("get_argument_index_for_region: arg_ty = {arg_ty:?}");
-                    tcx.any_free_region_meets(arg_ty, |r| r.to_region_vid() == fr)
+                    tcx.any_free_region_meets(arg_ty, |r| r.as_var() == fr)
                 },
             )?;
 
@@ -113,7 +113,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     pub(crate) fn get_argument_name_and_span_for_region(
         &self,
         body: &Body<'tcx>,
-        local_names: &IndexVec<Local, Option<Symbol>>,
+        local_names: &IndexSlice<Local, Option<Symbol>>,
         argument_index: usize,
     ) -> (Option<Symbol>, Span) {
         let implicit_inputs = self.universal_regions().defining_ty.implicit_inputs();