Auto merge of #132623 - nnethercote:rustc_borrowck-cleanups-2, r=<try>

`rustc_borrowck` cleanups, part 2

The code under `do_mir_borrowck` is pretty messy, especially the various types like `MirBorrowckCtxt`, `BorrowckInferCtxt`, `MirTypeckResults`, `MirTypeckRegionConstraints`, `CreateResult`, `TypeChecker`, `TypeVerifier`, `LivenessContext`, `LivenessResults`. This PR does some tidying up, though there's still plenty of mess left afterwards.

A sequel to #132250.

r? `@compiler-errors`

Author: bors

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -60,7 +60,7 @@ impl<'tcx> UniverseInfo<'tcx> {
             UniverseInfo::RelateTys { expected, found } => {
                 let err = mbcx.infcx.err_ctxt().report_mismatched_types(
                     &cause,
-                    mbcx.param_env,
+                    mbcx.infcx.param_env,
                     expected,
                     found,
                     TypeError::RegionsPlaceholderMismatch,

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -904,7 +904,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let ty = moved_place.ty(self.body, self.infcx.tcx).ty;
         debug!("ty: {:?}, kind: {:?}", ty, ty.kind());
 
-        let Some(assign_value) = self.infcx.err_ctxt().ty_kind_suggestion(self.param_env, ty)
+        let Some(assign_value) = self.infcx.err_ctxt().ty_kind_suggestion(self.infcx.param_env, ty)
         else {
             return;
         };
@@ -1304,7 +1304,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn implements_clone(&self, ty: Ty<'tcx>) -> bool {
         let Some(clone_trait_def) = self.infcx.tcx.lang_items().clone_trait() else { return false };
         self.infcx
-            .type_implements_trait(clone_trait_def, [ty], self.param_env)
+            .type_implements_trait(clone_trait_def, [ty], self.infcx.param_env)
             .must_apply_modulo_regions()
     }
 
@@ -1437,7 +1437,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let ocx = ObligationCtxt::new_with_diagnostics(self.infcx);
         let cause = ObligationCause::misc(span, self.mir_def_id());
 
-        ocx.register_bound(cause, self.param_env, ty, def_id);
+        ocx.register_bound(cause, self.infcx.param_env, ty, def_id);
         let errors = ocx.select_all_or_error();
 
         // Only emit suggestion if all required predicates are on generic
@@ -1957,7 +1957,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 && let ty::Ref(_, inner, _) = rcvr_ty.kind()
                 && let inner = inner.peel_refs()
                 && (Holds { ty: inner }).visit_ty(local_ty).is_break()
-                && let None = self.infcx.type_implements_trait_shallow(clone, inner, self.param_env)
+                && let None =
+                    self.infcx.type_implements_trait_shallow(clone, inner, self.infcx.param_env)
             {
                 err.span_label(
                     span,
@@ -1989,7 +1990,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             let obligation = Obligation::new(
                 self.infcx.tcx,
                 ObligationCause::dummy(),
-                self.param_env,
+                self.infcx.param_env,
                 trait_ref,
             );
             self.infcx.err_ctxt().suggest_derive(
@@ -3398,7 +3399,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             if let Some(iter_trait) = tcx.get_diagnostic_item(sym::Iterator)
                 && self
                     .infcx
-                    .type_implements_trait(iter_trait, [return_ty], self.param_env)
+                    .type_implements_trait(iter_trait, [return_ty], self.infcx.param_env)
                     .must_apply_modulo_regions()
             {
                 err.span_suggestion_hidden(
@@ -3837,11 +3838,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             if tcx.is_diagnostic_item(sym::deref_method, method_did) {
                 let deref_target =
                     tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
-                        Instance::try_resolve(tcx, self.param_env, deref_target, method_args)
+                        Instance::try_resolve(tcx, self.infcx.param_env, deref_target, method_args)
                             .transpose()
                     });
                 if let Some(Ok(instance)) = deref_target {
-                    let deref_target_ty = instance.ty(tcx, self.param_env);
+                    let deref_target_ty = instance.ty(tcx, self.infcx.param_env);
                     err.note(format!("borrow occurs due to deref coercion to `{deref_target_ty}`"));
                     err.span_note(tcx.def_span(instance.def_id()), "deref defined here");
                 }

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -864,7 +864,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
 
             let kind = call_kind(
                 self.infcx.tcx,
-                self.param_env,
+                self.infcx.param_env,
                 method_did,
                 method_args,
                 *fn_span,
@@ -1160,7 +1160,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         let suggest = match tcx.get_diagnostic_item(sym::IntoIterator) {
                             Some(def_id) => type_known_to_meet_bound_modulo_regions(
                                 self.infcx,
-                                self.param_env,
+                                self.infcx.param_env,
                                 Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, ty),
                                 def_id,
                             ),
@@ -1224,7 +1224,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                                 BoundRegionConversionTime::FnCall,
                                 tcx.fn_sig(method_did).instantiate(tcx, method_args).input(0),
                             )
-                            && self.infcx.can_eq(self.param_env, ty, self_ty)
+                            && self.infcx.can_eq(self.infcx.param_env, ty, self_ty)
                         {
                             err.subdiagnostic(CaptureReasonSuggest::FreshReborrow {
                                 span: move_span.shrink_to_hi(),
@@ -1258,7 +1258,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                             if let Some(errors) = self.infcx.type_implements_trait_shallow(
                                 clone_trait,
                                 ty,
-                                self.param_env,
+                                self.infcx.param_env,
                             ) && !has_sugg
                             {
                                 let msg = match &errors[..] {

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -1242,7 +1242,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                             .type_implements_trait_shallow(
                                 clone_trait,
                                 ty.peel_refs(),
-                                self.param_env,
+                                self.infcx.param_env,
                             )
                             .as_deref()
                         {
@@ -1279,7 +1279,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                                 let obligation = traits::Obligation::new(
                                     self.infcx.tcx,
                                     traits::ObligationCause::dummy(),
-                                    self.param_env,
+                                    self.infcx.param_env,
                                     trait_ref,
                                 );
                                 self.infcx.err_ctxt().suggest_derive(

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -952,7 +952,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
 
             if let Ok(Some(instance)) = ty::Instance::try_resolve(
                 tcx,
-                self.param_env,
+                self.infcx.param_env,
                 *fn_did,
                 self.infcx.resolve_vars_if_possible(args),
             ) {
@@ -1091,7 +1091,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             peeled_ty = ref_ty;
             count += 1;
         }
-        if !self.infcx.type_is_copy_modulo_regions(self.param_env, peeled_ty) {
+        if !self.infcx.type_is_copy_modulo_regions(self.infcx.param_env, peeled_ty) {
             return;
         }
 
@@ -1160,7 +1160,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let ocx = ObligationCtxt::new(&self.infcx);
         ocx.register_obligations(preds.iter().map(|(pred, span)| {
             trace!(?pred);
-            Obligation::misc(tcx, span, self.mir_def_id(), self.param_env, pred)
+            Obligation::misc(tcx, span, self.mir_def_id(), self.infcx.param_env, pred)
         }));
 
         if ocx.select_all_or_error().is_empty() && count > 0 {

compiler/rustc_borrowck/src/lib.rs

@@ -140,7 +140,6 @@ fn do_mir_borrowck<'tcx>(
 ) -> (BorrowCheckResult<'tcx>, Option<Box<BodyWithBorrowckFacts<'tcx>>>) {
     let def = input_body.source.def_id().expect_local();
     let infcx = BorrowckInferCtxt::new(tcx, def);
-    let param_env = tcx.param_env(def);
 
     let mut local_names = IndexVec::from_elem(None, &input_body.local_decls);
     for var_debug_info in &input_body.var_debug_info {
@@ -175,8 +174,7 @@ fn do_mir_borrowck<'tcx>(
     // will have a lifetime tied to the inference context.
     let mut body_owned = input_body.clone();
     let mut promoted = input_promoted.to_owned();
-    let free_regions =
-        nll::replace_regions_in_mir(&infcx, param_env, &mut body_owned, &mut promoted);
+    let free_regions = nll::replace_regions_in_mir(&infcx, &mut body_owned, &mut promoted);
     let body = &body_owned; // no further changes
 
     // FIXME(-Znext-solver): A bit dubious that we're only registering
@@ -192,7 +190,7 @@ fn do_mir_borrowck<'tcx>(
         .iter_enumerated()
         .map(|(idx, body)| (idx, MoveData::gather_moves(body, tcx, |_| true)));
 
-    let mut flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
+    let flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
         .iterate_to_fixpoint(tcx, body, Some("borrowck"))
         .into_results_cursor(body);
 
@@ -213,11 +211,9 @@ fn do_mir_borrowck<'tcx>(
         body,
         &promoted,
         &location_table,
-        param_env,
-        &mut flow_inits,
+        flow_inits,
         &move_data,
         &borrow_set,
-        tcx.closure_captures(def),
         consumer_options,
     );
 
@@ -229,11 +225,6 @@ fn do_mir_borrowck<'tcx>(
     // information.
     nll::dump_annotation(&infcx, body, &regioncx, &opt_closure_req, &opaque_type_values, diags);
 
-    // The various `flow_*` structures can be large. We drop `flow_inits` here
-    // so it doesn't overlap with the others below. This reduces peak memory
-    // usage significantly on some benchmarks.
-    drop(flow_inits);
-
     let flow_borrows = Borrows::new(tcx, body, &regioncx, &borrow_set).iterate_to_fixpoint(
         tcx,
         body,
@@ -268,7 +259,6 @@ fn do_mir_borrowck<'tcx>(
         let promoted_body = &promoted[idx];
         let mut promoted_mbcx = MirBorrowckCtxt {
             infcx: &infcx,
-            param_env,
             body: promoted_body,
             move_data: &move_data,
             location_table: &location_table, // no need to create a real one for the promoted, it is not used
@@ -308,7 +298,6 @@ fn do_mir_borrowck<'tcx>(
 
     let mut mbcx = MirBorrowckCtxt {
         infcx: &infcx,
-        param_env,
         body,
         move_data: &move_data,
         location_table: &location_table,
@@ -429,12 +418,14 @@ fn do_mir_borrowck<'tcx>(
 pub(crate) struct BorrowckInferCtxt<'tcx> {
     pub(crate) infcx: InferCtxt<'tcx>,
     pub(crate) reg_var_to_origin: RefCell<FxIndexMap<ty::RegionVid, RegionCtxt>>,
+    pub(crate) param_env: ParamEnv<'tcx>,
 }
 
 impl<'tcx> BorrowckInferCtxt<'tcx> {
     pub(crate) fn new(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
         let infcx = tcx.infer_ctxt().build(TypingMode::analysis_in_body(tcx, def_id));
-        BorrowckInferCtxt { infcx, reg_var_to_origin: RefCell::new(Default::default()) }
+        let param_env = tcx.param_env(def_id);
+        BorrowckInferCtxt { infcx, reg_var_to_origin: RefCell::new(Default::default()), param_env }
     }
 
     pub(crate) fn next_region_var<F>(
@@ -513,7 +504,6 @@ impl<'tcx> Deref for BorrowckInferCtxt<'tcx> {
 
 struct MirBorrowckCtxt<'a, 'infcx, 'tcx> {
     infcx: &'infcx BorrowckInferCtxt<'tcx>,
-    param_env: ParamEnv<'tcx>,
     body: &'a Body<'tcx>,
     move_data: &'a MoveData<'tcx>,
 

compiler/rustc_borrowck/src/nll.rs

@@ -30,7 +30,7 @@ use crate::diagnostics::RegionErrors;
 use crate::facts::{AllFacts, AllFactsExt, RustcFacts};
 use crate::location::LocationTable;
 use crate::region_infer::RegionInferenceContext;
-use crate::type_check::{self, MirTypeckRegionConstraints, MirTypeckResults};
+use crate::type_check::{self, MirTypeckResults};
 use crate::universal_regions::UniversalRegions;
 use crate::{BorrowckInferCtxt, polonius, renumber};
 
@@ -50,10 +50,9 @@ pub(crate) struct NllOutput<'tcx> {
 /// Rewrites the regions in the MIR to use NLL variables, also scraping out the set of universal
 /// regions (e.g., region parameters) declared on the function. That set will need to be given to
 /// `compute_regions`.
-#[instrument(skip(infcx, param_env, body, promoted), level = "debug")]
+#[instrument(skip(infcx, body, promoted), level = "debug")]
 pub(crate) fn replace_regions_in_mir<'tcx>(
     infcx: &BorrowckInferCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
     body: &mut Body<'tcx>,
     promoted: &mut IndexSlice<Promoted, Body<'tcx>>,
 ) -> UniversalRegions<'tcx> {
@@ -62,7 +61,7 @@ pub(crate) fn replace_regions_in_mir<'tcx>(
     debug!(?def);
 
     // Compute named region information. This also renumbers the inputs/outputs.
-    let universal_regions = UniversalRegions::new(infcx, def, param_env);
+    let universal_regions = UniversalRegions::new(infcx, def);
 
     // Replace all remaining regions with fresh inference variables.
     renumber::renumber_mir(infcx, body, promoted);
@@ -81,11 +80,9 @@ pub(crate) fn compute_regions<'a, 'tcx>(
     body: &Body<'tcx>,
     promoted: &IndexSlice<Promoted, Body<'tcx>>,
     location_table: &LocationTable,
-    param_env: ty::ParamEnv<'tcx>,
-    flow_inits: &mut ResultsCursor<'a, 'tcx, MaybeInitializedPlaces<'a, 'tcx>>,
+    flow_inits: ResultsCursor<'a, 'tcx, MaybeInitializedPlaces<'a, 'tcx>>,
     move_data: &MoveData<'tcx>,
     borrow_set: &BorrowSet<'tcx>,
-    upvars: &[&ty::CapturedPlace<'tcx>],
     consumer_options: Option<ConsumerOptions>,
 ) -> NllOutput<'tcx> {
     let is_polonius_legacy_enabled = infcx.tcx.sess.opts.unstable_opts.polonius.is_legacy_enabled();
@@ -96,41 +93,27 @@ pub(crate) fn compute_regions<'a, 'tcx>(
     let mut all_facts =
         (polonius_input || AllFacts::enabled(infcx.tcx)).then_some(AllFacts::default());
 
-    let universal_regions = Rc::new(universal_regions);
-
     let elements = Rc::new(DenseLocationMap::new(body));
 
     // Run the MIR type-checker.
     let MirTypeckResults { constraints, universal_region_relations, opaque_type_values } =
         type_check::type_check(
             infcx,
-            param_env,
             body,
             promoted,
-            Rc::clone(&universal_regions),
+            universal_regions,
             location_table,
             borrow_set,
             &mut all_facts,
             flow_inits,
             move_data,
             Rc::clone(&elements),
-            upvars,
         );
 
     // Create the region inference context, taking ownership of the
     // region inference data that was contained in `infcx`, and the
     // base constraints generated by the type-check.
     let var_origins = infcx.get_region_var_origins();
-    let MirTypeckRegionConstraints {
-        placeholder_indices,
-        placeholder_index_to_region: _,
-        liveness_constraints,
-        mut outlives_constraints,
-        mut member_constraints,
-        universe_causes,
-        type_tests,
-    } = constraints;
-    let placeholder_indices = Rc::new(placeholder_indices);
 
     // If requested, emit legacy polonius facts.
     polonius::emit_facts(
@@ -140,31 +123,14 @@ pub(crate) fn compute_regions<'a, 'tcx>(
         body,
         borrow_set,
         move_data,
-        &universal_regions,
         &universal_region_relations,
     );
 
-    if let Some(guar) = universal_regions.tainted_by_errors() {
-        // Suppress unhelpful extra errors in `infer_opaque_types` by clearing out all
-        // outlives bounds that we may end up checking.
-        outlives_constraints = Default::default();
-        member_constraints = Default::default();
-
-        // Also taint the entire scope.
-        infcx.set_tainted_by_errors(guar);
-    }
-
     let mut regioncx = RegionInferenceContext::new(
         infcx,
         var_origins,
-        universal_regions,
-        placeholder_indices,
+        constraints,
         universal_region_relations,
-        outlives_constraints,
-        member_constraints,
-        universe_causes,
-        type_tests,
-        liveness_constraints,
         elements,
     );