Toolchain upgrade to nightly-2025-10-07

crates/flux-infer/src/projections.rs

@@ -223,7 +223,7 @@ impl<'a, 'infcx, 'genv, 'tcx> Normalizer<'a, 'infcx, 'genv, 'tcx> {
                 let assoc_type_id = tcx
                     .associated_items(impl_def_id)
                     .in_definition_order()
-                    .find(|item| item.trait_item_def_id == Some(obligation.def_id))
+                    .find(|item| item.trait_item_def_id() == Some(obligation.def_id))
                     .map(|item| item.def_id)
                     .ok_or_else(|| {
                         query_bug!("no associated type for {obligation:?} in impl {impl_def_id:?}")
@@ -368,7 +368,7 @@ impl<'a, 'infcx, 'genv, 'tcx> Normalizer<'a, 'infcx, 'genv, 'tcx> {
         candidates: &mut Vec<Candidate>,
     ) -> QueryResult {
         let trait_ref = obligation.to_rustc(self.tcx()).trait_ref(self.tcx());
-        let trait_ref = self.tcx().erase_regions(trait_ref);
+        let trait_ref = self.tcx().erase_and_anonymize_regions(trait_ref);
         let trait_pred = Obligation::new(
             self.tcx(),
             ObligationCause::dummy(),
@@ -727,7 +727,7 @@ fn normalize_projection_ty_with_rustc<'tcx>(
 ) -> QueryResult<(bool, SubsetTyCtor)> {
     let tcx = genv.tcx();
     let projection_ty = obligation.to_rustc(tcx);
-    let projection_ty = tcx.erase_regions(projection_ty);
+    let projection_ty = tcx.erase_and_anonymize_regions(projection_ty);
     let cause = ObligationCause::dummy();
     let param_env = tcx.param_env(def_id);
 
@@ -813,7 +813,7 @@ fn get_impl_data_for_alias_reft<'tcx>(
     let tcx = infcx.tcx;
     let mut selcx = SelectionContext::new(infcx);
     let trait_ref = alias_reft.to_rustc_trait_ref(tcx);
-    let trait_ref = tcx.erase_regions(trait_ref);
+    let trait_ref = tcx.erase_and_anonymize_regions(trait_ref);
     let trait_pred =
         Obligation::new(tcx, ObligationCause::dummy(), tcx.param_env(def_id), trait_ref);
     match selcx.select(&trait_pred) {

crates/flux-middle/src/rty/mod.rs

@@ -2006,7 +2006,7 @@ impl<'tcx> ToRustc<'tcx> for BaseTy {
                     .map(|pred| pred.to_rustc(tcx))
                     .collect_vec();
                 let preds = tcx.mk_poly_existential_predicates(&preds);
-                ty::Ty::new_dynamic(tcx, preds, re.to_rustc(tcx), rustc_middle::ty::DynKind::Dyn)
+                ty::Ty::new_dynamic(tcx, preds, re.to_rustc(tcx))
             }
             BaseTy::Coroutine(def_id, resume_ty, upvars) => {
                 bug!("TODO: Generator {def_id:?} {resume_ty:?} {upvars:?}")

crates/flux-refineck/src/checker.rs

@@ -400,7 +400,7 @@ fn find_trait_item(
         && let Some(impl_trait_ref) = genv.impl_trait_ref(impl_id)?
     {
         let impl_trait_ref = impl_trait_ref.instantiate_identity();
-        let trait_item_id = tcx.associated_item(def_id).trait_item_def_id.unwrap();
+        let trait_item_id = tcx.associated_item(def_id).trait_item_def_id().unwrap();
         return Ok(Some((impl_trait_ref, trait_item_id)));
     }
     Ok(None)
@@ -1266,7 +1266,6 @@ impl<'ck, 'genv, 'tcx, M: Mode> Checker<'ck, 'genv, 'tcx, M> {
                     .with_span(stmt_span)
             }
             Rvalue::NullaryOp(null_op, ty) => Ok(self.check_nullary_op(*null_op, ty)),
-            Rvalue::Len(place) => self.check_len(infcx, env, stmt_span, place),
             Rvalue::UnaryOp(UnOp::PtrMetadata, Operand::Copy(place))
             | Rvalue::UnaryOp(UnOp::PtrMetadata, Operand::Move(place)) => {
                 self.check_raw_ptr_metadata(infcx, env, stmt_span, place)
@@ -1366,26 +1365,6 @@ impl<'ck, 'genv, 'tcx, M: Mode> Checker<'ck, 'genv, 'tcx, M> {
         }
     }
 
-    fn check_len(
-        &mut self,
-        infcx: &mut InferCtxt,
-        env: &mut TypeEnv,
-        stmt_span: Span,
-        place: &Place,
-    ) -> Result<Ty> {
-        let ty = env
-            .lookup_place(&mut infcx.at(stmt_span), place)
-            .with_span(stmt_span)?;
-
-        let idx = match ty.kind() {
-            TyKind::Indexed(BaseTy::Array(_, len), _) => Expr::from_const(self.genv.tcx(), len),
-            TyKind::Indexed(BaseTy::Slice(_), idx) => idx.clone(),
-            _ => tracked_span_bug!("check_len: expected array or slice type found  `{ty:?}`"),
-        };
-
-        Ok(Ty::indexed(BaseTy::Uint(UintTy::Usize), idx))
-    }
-
     fn check_binary_op(
         &mut self,
         infcx: &mut InferCtxt,

crates/flux-refineck/src/ghost_statements/fold_unfold.rs

@@ -298,9 +298,6 @@ impl<M: Mode> FoldUnfoldAnalysis<'_, '_, '_, M> {
             }
             StatementKind::Assign(place, rvalue) => {
                 match rvalue {
-                    Rvalue::Len(place) => {
-                        M::projection(self, env, place)?;
-                    }
                     Rvalue::UnaryOp(UnOp::PtrMetadata, Operand::Copy(place))
                     | Rvalue::UnaryOp(UnOp::PtrMetadata, Operand::Move(place)) => {
                         let deref_place = place.deref();

crates/flux-rustc-bridge/src/lowering.rs

@@ -92,7 +92,7 @@ fn trait_ref_impl_id<'tcx>(
     param_env: ParamEnv<'tcx>,
     trait_ref: rustc_ty::TraitRef<'tcx>,
 ) -> Option<(DefId, rustc_middle::ty::GenericArgsRef<'tcx>)> {
-    let trait_ref = tcx.erase_regions(trait_ref);
+    let trait_ref = tcx.erase_and_anonymize_regions(trait_ref);
     let obligation = Obligation::new(tcx, ObligationCause::dummy(), param_env, trait_ref);
     let impl_source = selcx.select(&obligation).ok()??;
     let impl_source = selcx.infcx.resolve_vars_if_possible(impl_source);
@@ -455,7 +455,6 @@ impl<'sess, 'tcx> MirLoweringCtxt<'_, 'sess, 'tcx> {
             rustc_mir::Rvalue::RawPtr(kind, place) => {
                 Ok(Rvalue::RawPtr(*kind, lower_place(self.tcx, place)?))
             }
-            rustc_mir::Rvalue::Len(place) => Ok(Rvalue::Len(lower_place(self.tcx, place)?)),
             rustc_mir::Rvalue::Cast(kind, op, ty) => {
                 let kind = self.lower_cast_kind(*kind).ok_or_else(|| {
                     UnsupportedReason::new(format!("unsupported cast `{kind:?}`"))
@@ -897,7 +896,7 @@ impl<'tcx> Lower<'tcx> for rustc_ty::Ty<'tcx> {
                 let args = args.lower(tcx)?;
                 Ok(Ty::mk_generator_witness(*did, args))
             }
-            rustc_ty::Dynamic(predicates, region, rustc_ty::DynKind::Dyn) => {
+            rustc_ty::Dynamic(predicates, region) => {
                 let region = region.lower(tcx)?;
 
                 let exi_preds = List::from_vec(
@@ -1020,19 +1019,22 @@ impl<'tcx> Lower<'tcx> for rustc_middle::ty::Region<'tcx> {
     type R = Result<Region, UnsupportedReason>;
 
     fn lower(self, _tcx: TyCtxt<'tcx>) -> Self::R {
-        use rustc_middle::ty::RegionKind;
+        use rustc_middle::ty;
         match self.kind() {
-            RegionKind::ReVar(rvid) => Ok(Region::ReVar(rvid)),
-            RegionKind::ReBound(debruijn, bregion) => {
+            ty::ReVar(rvid) => Ok(Region::ReVar(rvid)),
+            ty::ReBound(ty::BoundVarIndexKind::Bound(debruijn), bregion) => {
                 Ok(Region::ReBound(
                     debruijn,
                     Ok(BoundRegion { kind: bregion.kind, var: bregion.var })?,
                 ))
             }
-            RegionKind::ReEarlyParam(bregion) => Ok(Region::ReEarlyParam(bregion)),
-            RegionKind::ReStatic => Ok(Region::ReStatic),
-            RegionKind::ReErased => Ok(Region::ReErased),
-            RegionKind::ReLateParam(_) | RegionKind::RePlaceholder(_) | RegionKind::ReError(_) => {
+            ty::ReEarlyParam(bregion) => Ok(Region::ReEarlyParam(bregion)),
+            ty::ReStatic => Ok(Region::ReStatic),
+            ty::ReErased => Ok(Region::ReErased),
+            ty::ReBound(ty::BoundVarIndexKind::Canonical, _)
+            | ty::ReLateParam(_)
+            | ty::RePlaceholder(_)
+            | ty::ReError(_) => {
                 Err(UnsupportedReason::new(format!("unsupported region `{self:?}`")))
             }
         }

crates/flux-rustc-bridge/src/mir.rs

@@ -207,7 +207,6 @@ pub enum Rvalue {
     Repeat(Operand, Const),
     Ref(Region, BorrowKind, Place),
     RawPtr(RawPtrKind, Place),
-    Len(Place),
     Cast(CastKind, Operand, Ty),
     BinaryOp(BinOp, Operand, Operand),
     NullaryOp(NullOp, Ty),
@@ -721,7 +720,6 @@ impl fmt::Debug for Rvalue {
             Rvalue::Aggregate(AggregateKind::Tuple, args) => {
                 write!(f, "({:?})", args.iter().format(", "))
             }
-            Rvalue::Len(place) => write!(f, "Len({place:?})"),
             Rvalue::Cast(kind, op, ty) => write!(f, "{op:?} as {ty:?} [{kind:?}]"),
             Rvalue::Repeat(op, c) => write!(f, "[{op:?}; {c:?}]"),
             Rvalue::ShallowInitBox(op, ty) => write!(f, "ShallowInitBox({op:?}, {ty:?})"),

crates/flux-rustc-bridge/src/ty/mod.rs

@@ -963,7 +963,7 @@ impl<'tcx> ToRustc<'tcx> for Ty {
                     .collect_vec();
 
                 let preds = tcx.mk_poly_existential_predicates(&preds);
-                rustc_ty::Ty::new_dynamic(tcx, preds, re.to_rustc(tcx), rustc_ty::DynKind::Dyn)
+                rustc_ty::Ty::new_dynamic(tcx, preds, re.to_rustc(tcx))
             }
             TyKind::Coroutine(_, _) | TyKind::CoroutineWitness(_, _) => {
                 bug!("TODO: to_rustc for `{self:?}`")

crates/flux-syntax/src/symbols.rs

@@ -23,7 +23,6 @@ symbols! {
     Symbols {
         Map,
         Set,
-        hide,
         int,
         real,
     }

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2025-09-09"
+channel = "nightly-2025-10-07"
 components = ["rust-src", "rustc-dev", "llvm-tools", "rustfmt", "clippy"]