rust-lang · adwinwhite · May 22, 2026 · Jun 18, 2026 · Jun 18, 2026 · Jun 8, 2026
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -713,8 +713,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             ));
             let can_subst = |ty: Ty<'tcx>| {
                 // Normalize before comparing to see through type aliases and projections.
-                let old_ty = ty::EarlyBinder::bind(ty).instantiate(tcx, generic_args);
-                let new_ty = ty::EarlyBinder::bind(ty).instantiate(tcx, new_args);
+                let old_ty = ty::EarlyBinder::bind(tcx, ty).instantiate(tcx, generic_args);
+                let new_ty = ty::EarlyBinder::bind(tcx, ty).instantiate(tcx, new_args);
                 if let Ok(old_ty) = tcx.try_normalize_erasing_regions(
                     self.infcx.typing_env(self.infcx.param_env),
                     old_ty,

diff --git a/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs b/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs
@@ -76,6 +76,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         "non-defining use of `{}` in the defining scope",
                         Ty::new_opaque(
                             infcx.tcx,
+                            ty::IsRigid::No,
                             opaque_type_key.def_id.to_def_id(),
                             opaque_type_key.args
                         )
@@ -220,7 +221,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for FindOpaqueRegion<'_, 'tcx> {
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
         // If we find an opaque in a local ty, then for each of its captured regions,
         // try to find a path between that captured regions and our borrow region...
-        if let ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) = *ty.kind()
+        if let ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) = *ty.kind()
             && let hir::OpaqueTyOrigin::FnReturn { parent, in_trait_or_impl: None } =
                 self.tcx.opaque_ty_origin(def_id)
         {
@@ -277,7 +278,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for CheckExplicitRegionMentionAndCollectGen
 
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
         match *ty.kind() {
-            ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) => {
+            ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) => {
                 if self.seen_opaques.insert(def_id) {
                     for (bound, _) in self
                         .tcx

diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -603,7 +603,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let ErrorConstraintInfo { outlived_fr, span, .. } = errci;
 
         let mut output_ty = self.regioncx.universal_regions().unnormalized_output_ty;
-        if let ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, .. }) = *output_ty.kind() {
+        if let ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, .. }) = *output_ty.kind() {
             output_ty = self.infcx.tcx.type_of(def_id).instantiate_identity().skip_norm_wip()
         };
 

diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
@@ -1928,7 +1928,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                     | ty::Never
                     | ty::Tuple(_)
                     | ty::UnsafeBinder(_)
-                    | ty::Alias(_)
+                    | ty::Alias(_, _)
                     | ty::Param(_)
                     | ty::Bound(_, _)
                     | ty::Infer(_)
@@ -1970,7 +1970,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                     | ty::CoroutineWitness(..)
                     | ty::Never
                     | ty::UnsafeBinder(_)
-                    | ty::Alias(_)
+                    | ty::Alias(_, _)
                     | ty::Param(_)
                     | ty::Bound(_, _)
                     | ty::Infer(_)

diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/member_constraints.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/member_constraints.rs
@@ -176,7 +176,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for CollectMemberConstraintsVisitor<'_, '_,
             | ty::CoroutineClosure(def_id, args)
             | ty::Coroutine(def_id, args) => self.visit_closure_args(def_id, args),
 
-            ty::Alias(ty::AliasTy { kind, args, .. })
+            ty::Alias(_, ty::AliasTy { kind, args, .. })
                 if let Some(variances) = self.cx().opt_alias_variances(kind) =>
             {
                 // Skip lifetime parameters that are not captured, since they do

diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs
@@ -367,7 +367,7 @@ fn compute_definition_site_hidden_types_from_defining_uses<'tcx>(
         // usage of the opaque type and we can ignore it. This check is mirrored in typeck's
         // writeback.
         if !rcx.infcx.tcx.use_typing_mode_post_typeck_until_borrowck() {
-            if let &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) =
+            if let &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) =
                 hidden_type.ty.skip_binder().kind()
                 && def_id == opaque_type_key.def_id.to_def_id()
                 && args == opaque_type_key.args
@@ -500,7 +500,7 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for ToArgRegionsFolder<'_, 'tcx> {
                 Ty::new_coroutine(tcx, def_id, self.fold_closure_args(def_id, args)?)
             }
 
-            ty::Alias(ty::AliasTy { kind, args, .. })
+            ty::Alias(_, ty::AliasTy { kind, args, .. })
                 if let Some(variances) = tcx.opt_alias_variances(kind) =>
             {
                 let args = tcx.mk_args_from_iter(std::iter::zip(variances, args.iter()).map(
@@ -512,7 +512,7 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for ToArgRegionsFolder<'_, 'tcx> {
                         }
                     },
                 ))?;
-                ty::AliasTy::new_from_args(tcx, kind, args).to_ty(tcx)
+                ty::AliasTy::new_from_args(tcx, kind, args).to_ty(tcx, ty::IsRigid::No)
             }
 
             _ => ty.try_super_fold_with(self)?,
@@ -541,7 +541,7 @@ pub(crate) fn apply_definition_site_hidden_types<'tcx>(
     for &(key, hidden_type) in opaque_types {
         let Some(expected) = hidden_types.get(&key.def_id) else {
             if !tcx.use_typing_mode_post_typeck_until_borrowck() {
-                if let &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) =
+                if let &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) =
                     hidden_type.ty.kind()
                     && def_id == key.def_id.to_def_id()
                     && args == key.args

diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -469,7 +469,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             // Necessary for non-trivial patterns whose user-type annotation is an opaque type,
             // e.g. `let (_a,): Tait = whatever`, see #105897
             if !self.infcx.next_trait_solver()
-                && let ty::Alias(ty::AliasTy { kind: ty::Opaque { .. }, .. }) =
+                && let ty::Alias(_, ty::AliasTy { kind: ty::Opaque { .. }, .. }) =
                     curr_projected_ty.ty.kind()
             {
                 // There is nothing that we can compare here if we go through an opaque type.
@@ -1760,7 +1760,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
             let tcx = self.tcx();
             let maybe_uneval = match constant.const_ {
                 Const::Ty(_, ct) => match ct.kind() {
-                    ty::ConstKind::Unevaluated(uv) => match uv.kind {
+                    ty::ConstKind::Unevaluated(_, uv) => match uv.kind {
                         ty::UnevaluatedConstKind::Projection { def_id }
                         | ty::UnevaluatedConstKind::Inherent { def_id }
                         | ty::UnevaluatedConstKind::Free { def_id }

diff --git a/compiler/rustc_borrowck/src/type_check/relate_tys.rs b/compiler/rustc_borrowck/src/type_check/relate_tys.rs
@@ -150,10 +150,10 @@ impl<'a, 'b, 'tcx> NllTypeRelating<'a, 'b, 'tcx> {
         };
 
         let (a, b) = match (a.kind(), b.kind()) {
-            (&ty::Alias(ty::AliasTy { kind: ty::Opaque { .. }, .. }), _) => {
+            (&ty::Alias(_, ty::AliasTy { kind: ty::Opaque { .. }, .. }), _) => {
                 (a, enable_subtyping(b, true)?)
             }
-            (_, &ty::Alias(ty::AliasTy { kind: ty::Opaque { .. }, .. })) => {
+            (_, &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { .. }, .. })) => {
                 (enable_subtyping(a, false)?, b)
             }
             _ => unreachable!(
@@ -386,8 +386,8 @@ impl<'b, 'tcx> TypeRelation<TyCtxt<'tcx>> for NllTypeRelating<'_, 'b, 'tcx> {
             }
 
             (
-                &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id: a_def_id }, .. }),
-                &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id: b_def_id }, .. }),
+                &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id: a_def_id }, .. }),
+                &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id: b_def_id }, .. }),
             ) if a_def_id == b_def_id || infcx.next_trait_solver() => {
                 super_combine_tys(&infcx.infcx, self, a, b).map(|_| ()).or_else(|err| {
                     // This behavior is only there for the old solver, the new solver
@@ -401,8 +401,8 @@ impl<'b, 'tcx> TypeRelation<TyCtxt<'tcx>> for NllTypeRelating<'_, 'b, 'tcx> {
                     if a_def_id.is_local() { self.relate_opaques(a, b) } else { Err(err) }
                 })?;
             }
-            (&ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, .. }), _)
-            | (_, &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, .. }))
+            (&ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, .. }), _)
+            | (_, &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, .. }))
                 if def_id.is_local() && !self.type_checker.infcx.next_trait_solver() =>
             {
                 self.relate_opaques(a, b)?;

diff --git a/compiler/rustc_codegen_cranelift/src/common.rs b/compiler/rustc_codegen_cranelift/src/common.rs
@@ -349,7 +349,7 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
         self.instance.instantiate_mir_and_normalize_erasing_regions(
             self.tcx,
             ty::TypingEnv::fully_monomorphized(),
-            ty::EarlyBinder::bind(value),
+            ty::EarlyBinder::bind(self.tcx, value),
         )
     }
 

diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -136,7 +136,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         self.instance.instantiate_mir_and_normalize_erasing_regions(
             self.cx.tcx(),
             self.cx.typing_env(),
-            ty::EarlyBinder::bind(value),
+            ty::EarlyBinder::bind(self.cx.tcx(), value),
         )
     }
 }
@@ -219,7 +219,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         let monomorphized_mir = instance.instantiate_mir_and_normalize_erasing_regions(
             tcx,
             ty::TypingEnv::fully_monomorphized(),
-            ty::EarlyBinder::bind(mir.clone()),
+            ty::EarlyBinder::bind(tcx, mir.clone()),
         );
         mir = tcx.arena.alloc(optimize_use_clone::<Bx>(cx, monomorphized_mir));
     }

diff --git a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
@@ -67,15 +67,15 @@ fn inline_to_global_operand<'a, 'tcx, Cx: LayoutOf<'tcx, LayoutOfResult = TyAndL
                 .instantiate_mir_and_normalize_erasing_regions(
                     cx.tcx(),
                     cx.typing_env(),
-                    ty::EarlyBinder::bind(value.const_),
+                    ty::EarlyBinder::bind(cx.tcx(), value.const_),
                 )
                 .eval(cx.tcx(), cx.typing_env(), value.span)
                 .expect("erroneous constant missed by mono item collection");
 
             let mono_type = instance.instantiate_mir_and_normalize_erasing_regions(
                 cx.tcx(),
                 cx.typing_env(),
-                ty::EarlyBinder::bind(value.ty()),
+                ty::EarlyBinder::bind(cx.tcx(), value.ty()),
             );
 
             let string = common::asm_const_to_str(
@@ -91,7 +91,7 @@ fn inline_to_global_operand<'a, 'tcx, Cx: LayoutOf<'tcx, LayoutOfResult = TyAndL
             let mono_type = instance.instantiate_mir_and_normalize_erasing_regions(
                 cx.tcx(),
                 cx.typing_env(),
-                ty::EarlyBinder::bind(value.ty()),
+                ty::EarlyBinder::bind(cx.tcx(), value.ty()),
             );
 
             let instance = match mono_type.kind() {

diff --git a/compiler/rustc_const_eval/src/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/check_consts/qualifs.rs
@@ -345,7 +345,7 @@ where
         Const::Ty(_, ct) => match ct.kind() {
             ty::ConstKind::Param(_) | ty::ConstKind::Error(_) => None,
             // Unevaluated consts in MIR bodies don't have associated MIR (e.g. `type const`).
-            ty::ConstKind::Unevaluated(_) => None,
+            ty::ConstKind::Unevaluated(_, _) => None,
             // FIXME(mgca): Investigate whether using `None` for `ConstKind::Value` is overly
             // strict, and if instead we should be doing some kind of value-based analysis.
             ty::ConstKind::Value(_) => None,

diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -97,8 +97,8 @@ fn eval_body_using_ecx<'tcx, R: InterpretationResult<'tcx>>(
     body: &'tcx mir::Body<'tcx>,
 ) -> InterpResult<'tcx, R> {
     let tcx = *ecx.tcx;
-    let layout =
-        ecx.layout_of(body.bound_return_ty().instantiate(tcx, cid.instance.args).skip_norm_wip())?;
+    let layout = ecx
+        .layout_of(body.bound_return_ty(tcx).instantiate(tcx, cid.instance.args).skip_norm_wip())?;
     let (intern_kind, ret) = setup_for_eval(ecx, cid, layout)?;
 
     trace!(

diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -362,7 +362,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             .try_instantiate_mir_and_normalize_erasing_regions(
                 *self.tcx,
                 self.typing_env,
-                ty::EarlyBinder::bind(value),
+                ty::EarlyBinder::bind(self.tcx.tcx, value),
             )
             .map_err(|_| ErrorHandled::TooGeneric(self.cur_span()))
     }

diff --git a/compiler/rustc_const_eval/src/util/type_name.rs b/compiler/rustc_const_eval/src/util/type_name.rs
@@ -53,20 +53,21 @@ impl<'tcx> Printer<'tcx> for TypeNamePrinter<'tcx> {
             // Types with identity (print the module path).
             ty::Adt(ty::AdtDef(Interned(&ty::AdtDefData { did: def_id, .. }, _)), args)
             | ty::FnDef(def_id, args)
-            | ty::Alias(ty::AliasTy {
-                kind: ty::Projection { def_id } | ty::Opaque { def_id },
-                args,
-                ..
-            })
+            | ty::Alias(
+                _,
+                ty::AliasTy {
+                    kind: ty::Projection { def_id } | ty::Opaque { def_id }, args, ..
+                },
+            )
             | ty::Closure(def_id, args)
             | ty::CoroutineClosure(def_id, args)
             | ty::Coroutine(def_id, args) => self.print_def_path(def_id, args),
             ty::Foreign(def_id) => self.print_def_path(def_id, &[]),
 
-            ty::Alias(ty::AliasTy { kind: ty::Free { .. }, .. }) => {
+            ty::Alias(_, ty::AliasTy { kind: ty::Free { .. }, .. }) => {
                 bug!("type_name: unexpected free alias")
             }
-            ty::Alias(ty::AliasTy { kind: ty::Inherent { .. }, .. }) => {
+            ty::Alias(_, ty::AliasTy { kind: ty::Inherent { .. }, .. }) => {
                 bug!("type_name: unexpected inherent projection")
             }
             ty::CoroutineWitness(..) => bug!("type_name: unexpected `CoroutineWitness`"),

diff --git a/compiler/rustc_hir_analysis/src/autoderef.rs b/compiler/rustc_hir_analysis/src/autoderef.rs
@@ -165,8 +165,9 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
             return None;
         }
 
-        let (normalized_ty, obligations) = self
-            .normalize_ty(Unnormalized::new(Ty::new_projection(tcx, trait_target_def_id, [ty])))?;
+        let (normalized_ty, obligations) = self.normalize_ty(Unnormalized::new(
+            Ty::new_projection(tcx, ty::IsRigid::No, trait_target_def_id, [ty]),
+        ))?;
         debug!("overloaded_deref_ty({:?}) = ({:?}, {:?})", ty, normalized_ty, obligations);
         self.state.obligations.extend(obligations);
 

diff --git a/compiler/rustc_hir_analysis/src/check/always_applicable.rs b/compiler/rustc_hir_analysis/src/check/always_applicable.rs
@@ -192,8 +192,9 @@ fn ensure_all_fields_are_const_destruct<'tcx>(
     let ocx = ObligationCtxt::new_with_diagnostics(&infcx);
 
     let impl_span = tcx.def_span(impl_def_id.to_def_id());
-    let env =
-        ty::EarlyBinder::bind(tcx.param_env(impl_def_id)).instantiate_identity().skip_norm_wip();
+    let env = ty::EarlyBinder::bind(tcx, tcx.param_env(impl_def_id))
+        .instantiate_identity()
+        .skip_norm_wip();
     let args = ty::GenericArgs::identity_for_item(tcx, impl_def_id);
     let destruct_trait = tcx.lang_items().destruct_trait().unwrap();
     for field in tcx.adt_def(adt_def_id).all_fields() {
@@ -281,7 +282,7 @@ fn ensure_impl_predicates_are_implied_by_item_defn<'tcx>(
     // reference the params from the ADT instead of from the impl which is bad UX. To resolve
     // this we "rename" the ADT's params to be the impl's params which should not affect behaviour.
     let impl_adt_ty = Ty::new_adt(tcx, tcx.adt_def(adt_def_id), adt_to_impl_args);
-    let adt_env = ty::EarlyBinder::bind(tcx.param_env(adt_def_id))
+    let adt_env = ty::EarlyBinder::bind(tcx, tcx.param_env(adt_def_id))
         .instantiate(tcx, adt_to_impl_args)
         .skip_norm_wip();
 

diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -337,7 +337,7 @@ fn check_opaque_meets_bounds<'tcx>(
         }),
     };
 
-    let opaque_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
+    let opaque_ty = Ty::new_opaque(tcx, ty::IsRigid::No, def_id.to_def_id(), args);
 
     // `ReErased` regions appear in the "parent_args" of closures/coroutines.
     // We're ignoring them here and replacing them with fresh region variables.
@@ -534,7 +534,7 @@ fn sanity_check_found_hidden_type<'tcx>(
         // Nothing was actually constrained.
         return Ok(());
     }
-    if let &ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) = ty.ty.kind() {
+    if let &ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id }, args, .. }) = ty.ty.kind() {
         if def_id == key.def_id.to_def_id() && args == key.args {
             // Nothing was actually constrained, this is an opaque usage that was
             // only discovered to be opaque after inference vars resolved.
@@ -778,7 +778,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                 if has_default {
                     // need to store default and type of default
                     let ct = tcx.const_param_default(param.def_id).skip_binder();
-                    if let ty::ConstKind::Unevaluated(uv) = ct.kind()
+                    if let ty::ConstKind::Unevaluated(_, uv) = ct.kind()
                         && let Some(def_id) = uv.kind.opt_def_id()
                     {
                         tcx.ensure_ok().type_of(def_id);
@@ -2191,7 +2191,7 @@ fn opaque_type_cycle_error(tcx: TyCtxt<'_>, opaque_def_id: LocalDefId) -> ErrorG
                 impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector {
                     fn visit_ty(&mut self, t: Ty<'tcx>) {
                         match *t.kind() {
-                            ty::Alias(ty::AliasTy { kind: ty::Opaque { def_id: def }, .. }) => {
+                            ty::Alias(_, ty::AliasTy { kind: ty::Opaque { def_id: def }, .. }) => {
                                 self.opaques.push(def);
                             }
                             ty::Closure(def_id, ..) | ty::Coroutine(def_id, ..) => {
@@ -2224,10 +2224,13 @@ fn opaque_type_cycle_error(tcx: TyCtxt<'_>, opaque_def_id: LocalDefId) -> ErrorG
                     let mut label_match = |ty: Ty<'_>, span| {
                         for arg in ty.walk() {
                             if let ty::GenericArgKind::Type(ty) = arg.kind()
-                                && let ty::Alias(ty::AliasTy {
-                                    kind: ty::Opaque { def_id: captured_def_id },
-                                    ..
-                                }) = *ty.kind()
+                                && let ty::Alias(
+                                    _,
+                                    ty::AliasTy {
+                                        kind: ty::Opaque { def_id: captured_def_id },
+                                        ..
+                                    },
+                                ) = *ty.kind()
                                 && captured_def_id == opaque_def_id.to_def_id()
                             {
                                 err.span_label(