rename erase_regions to erase_and_anonymize_regions

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -627,7 +627,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             }
 
             // Type-test failed. Report the error.
-            let erased_generic_kind = infcx.tcx.erase_regions(type_test.generic_kind);
+            let erased_generic_kind = infcx.tcx.erase_and_anonymize_regions(type_test.generic_kind);
 
             // Skip duplicate-ish errors.
             if deduplicate_errors.insert((

compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs

@@ -344,7 +344,7 @@ fn compute_concrete_types_from_defining_uses<'tcx>(
         //
         // FIXME(-Znext-solver): This isn't necessary after all. We can remove this check again.
         if let Some((prev_decl_key, prev_span)) = decls_modulo_regions.insert(
-            rcx.infcx.tcx.erase_regions(opaque_type_key),
+            rcx.infcx.tcx.erase_and_anonymize_regions(opaque_type_key),
             (opaque_type_key, hidden_type.span),
         ) && let Some((arg1, arg2)) = std::iter::zip(
             prev_decl_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg),

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1874,7 +1874,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         if is_diverging {
             // The signature in this call can reference region variables,
             // so erase them before calling a query.
-            let output_ty = self.tcx().erase_regions(sig.output());
+            let output_ty = self.tcx().erase_and_anonymize_regions(sig.output());
             if !output_ty
                 .is_privately_uninhabited(self.tcx(), self.infcx.typing_env(self.infcx.param_env))
             {
@@ -1968,7 +1968,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
             let op_arg_ty = self.normalize(op_arg_ty, term_location);
             let category = if call_source.from_hir_call() {
-                ConstraintCategory::CallArgument(Some(self.infcx.tcx.erase_regions(func_ty)))
+                ConstraintCategory::CallArgument(Some(
+                    self.infcx.tcx.erase_and_anonymize_regions(func_ty),
+                ))
             } else {
                 ConstraintCategory::Boring
             };
@@ -2102,7 +2104,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         // Erase the regions from `ty` to get a global type. The
         // `Sized` bound in no way depends on precise regions, so this
         // shouldn't affect `is_sized`.
-        let erased_ty = tcx.erase_regions(ty);
+        let erased_ty = tcx.erase_and_anonymize_regions(ty);
         // FIXME(#132279): Using `Ty::is_sized` causes us to incorrectly handle opaques here.
         if !erased_ty.is_sized(tcx, self.infcx.typing_env(self.infcx.param_env)) {
             // in current MIR construction, all non-control-flow rvalue

compiler/rustc_codegen_gcc/src/type_of.rs

@@ -240,7 +240,7 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
 
         // Make sure lifetimes are erased, to avoid generating distinct LLVM
         // types for Rust types that only differ in the choice of lifetimes.
-        let normal_ty = cx.tcx.erase_regions(self.ty);
+        let normal_ty = cx.tcx.erase_and_anonymize_regions(self.ty);
 
         let mut defer = None;
         let ty = if self.ty != normal_ty {

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -1425,7 +1425,7 @@ fn build_vtable_type_di_node<'ll, 'tcx>(
 
     let vtable_entries = if let Some(poly_trait_ref) = poly_trait_ref {
         let trait_ref = poly_trait_ref.with_self_ty(tcx, ty);
-        let trait_ref = tcx.erase_regions(trait_ref);
+        let trait_ref = tcx.erase_and_anonymize_regions(trait_ref);
 
         tcx.vtable_entries(trait_ref)
     } else {
@@ -1552,7 +1552,7 @@ pub(crate) fn apply_vcall_visibility_metadata<'ll, 'tcx>(
     // Unwrap potential addrspacecast
     let vtable = find_vtable_behind_cast(vtable);
     let trait_ref_self = trait_ref.with_self_ty(cx.tcx, ty);
-    let trait_ref_self = cx.tcx.erase_regions(trait_ref_self);
+    let trait_ref_self = cx.tcx.erase_and_anonymize_regions(trait_ref_self);
     let trait_def_id = trait_ref_self.def_id;
     let trait_vis = cx.tcx.visibility(trait_def_id);
 

compiler/rustc_codegen_llvm/src/type_of.rs

@@ -226,7 +226,7 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
 
         // Make sure lifetimes are erased, to avoid generating distinct LLVM
         // types for Rust types that only differ in the choice of lifetimes.
-        let normal_ty = cx.tcx.erase_regions(self.ty);
+        let normal_ty = cx.tcx.erase_and_anonymize_regions(self.ty);
 
         let mut defer = None;
         let llty = if self.ty != normal_ty {

compiler/rustc_const_eval/src/interpret/traits.rs

@@ -23,7 +23,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     ) -> InterpResult<'tcx, Pointer<Option<M::Provenance>>> {
         trace!("get_vtable(ty={ty:?}, dyn_ty={dyn_ty:?})");
 
-        let (ty, dyn_ty) = self.tcx.erase_regions((ty, dyn_ty));
+        let (ty, dyn_ty) = self.tcx.erase_and_anonymize_regions((ty, dyn_ty));
 
         // All vtables must be monomorphic, bail out otherwise.
         ensure_monomorphic_enough(*self.tcx, ty)?;
@@ -53,8 +53,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     ) -> &'tcx [VtblEntry<'tcx>] {
         if let Some(trait_) = trait_ {
             let trait_ref = trait_.with_self_ty(*self.tcx, dyn_ty);
-            let trait_ref =
-                self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
+            let trait_ref = self.tcx.erase_and_anonymize_regions(
+                self.tcx.instantiate_bound_regions_with_erased(trait_ref),
+            );
             self.tcx.vtable_entries(trait_ref)
         } else {
             TyCtxt::COMMON_VTABLE_ENTRIES

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1047,7 +1047,7 @@ fn check_type_defn<'tcx>(
             let needs_drop_copy = || {
                 packed && {
                     let ty = tcx.type_of(variant.tail().did).instantiate_identity();
-                    let ty = tcx.erase_regions(ty);
+                    let ty = tcx.erase_and_anonymize_regions(ty);
                     assert!(!ty.has_infer());
                     ty.needs_drop(tcx, wfcx.infcx.typing_env(wfcx.param_env))
                 }

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -404,7 +404,7 @@ fn emit_orphan_check_error<'tcx>(
                     of_trait.trait_ref.path.span
                 };
 
-                ty = tcx.erase_regions(ty);
+                ty = tcx.erase_and_anonymize_regions(ty);
 
                 let is_foreign =
                     !trait_ref.def_id.is_local() && matches!(is_target_ty, IsFirstInputType::No);

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -482,7 +482,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 .map(|header| header.trait_ref.instantiate_identity().self_ty())
                 // We don't care about blanket impls.
                 .filter(|self_ty| !self_ty.has_non_region_param())
-                .map(|self_ty| tcx.erase_regions(self_ty).to_string())
+                .map(|self_ty| tcx.erase_and_anonymize_regions(self_ty).to_string())
                 .collect()
         };
         // FIXME: also look at `tcx.generics_of(self.item_def_id()).params` any that

compiler/rustc_hir_typeck/src/cast.rs

@@ -851,8 +851,8 @@ impl<'a, 'tcx> CastCheck<'tcx> {
         debug!("check_ptr_ptr_cast m_src={m_src:?} m_dst={m_dst:?}");
         // ptr-ptr cast. metadata must match.
 
-        let src_kind = fcx.tcx.erase_regions(fcx.pointer_kind(m_src.ty, self.span)?);
-        let dst_kind = fcx.tcx.erase_regions(fcx.pointer_kind(m_dst.ty, self.span)?);
+        let src_kind = fcx.tcx.erase_and_anonymize_regions(fcx.pointer_kind(m_src.ty, self.span)?);
+        let dst_kind = fcx.tcx.erase_and_anonymize_regions(fcx.pointer_kind(m_dst.ty, self.span)?);
 
         // We can't cast if target pointer kind is unknown
         let Some(dst_kind) = dst_kind else {

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1292,7 +1292,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .infcx
                 .type_implements_trait(
                     clone_trait_def,
-                    [self.tcx.erase_regions(expected_ty)],
+                    [self.tcx.erase_and_anonymize_regions(expected_ty)],
                     self.param_env,
                 )
                 .must_apply_modulo_regions()

compiler/rustc_hir_typeck/src/inline_asm.rs

@@ -44,7 +44,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
         if ty.has_non_region_infer() {
             Ty::new_misc_error(self.tcx())
         } else {
-            self.tcx().erase_regions(ty)
+            self.tcx().erase_and_anonymize_regions(ty)
         }
     }
 

compiler/rustc_hir_typeck/src/writeback.rs

@@ -788,7 +788,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                         format!("unexpected inference variable after writeback: {predicate:?}"),
                     );
                 } else {
-                    let predicate = self.tcx().erase_regions(predicate);
+                    let predicate = self.tcx().erase_and_anonymize_regions(predicate);
                     if cause.has_infer() || cause.has_placeholders() {
                         // We can't use the the obligation cause as it references
                         // information local to this query.
@@ -969,8 +969,8 @@ impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
         // borrowck, and specifically region constraints will be populated during
         // MIR typeck which is run on the new body.
         //
-        // We're not using `tcx.erase_regions` as that also anonymizes bound variables,
-        // regressing borrowck diagnostics.
+        // We're not using `tcx.erase_and_anonymize_regions` as that also
+        // anonymizes bound variables, regressing borrowck diagnostics.
         value = fold_regions(tcx, value, |_, _| tcx.lifetimes.re_erased);
 
         // Normalize consts in writeback, because GCE doesn't normalize eagerly.

compiler/rustc_infer/src/infer/outlives/test_type_match.rs

@@ -76,7 +76,7 @@ pub(super) fn can_match_erased_ty<'tcx>(
     erased_ty: Ty<'tcx>,
 ) -> bool {
     assert!(!outlives_predicate.has_escaping_bound_vars());
-    let erased_outlives_predicate = tcx.erase_regions(outlives_predicate);
+    let erased_outlives_predicate = tcx.erase_and_anonymize_regions(outlives_predicate);
     let outlives_ty = erased_outlives_predicate.skip_binder().0;
     if outlives_ty == erased_ty {
         // pointless micro-optimization

compiler/rustc_infer/src/infer/outlives/verify.rs

@@ -96,7 +96,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         &self,
         alias_ty: ty::AliasTy<'tcx>,
     ) -> Vec<ty::PolyTypeOutlivesPredicate<'tcx>> {
-        let erased_alias_ty = self.tcx.erase_regions(alias_ty.to_ty(self.tcx));
+        let erased_alias_ty = self.tcx.erase_and_anonymize_regions(alias_ty.to_ty(self.tcx));
         self.declared_generic_bounds_from_env_for_erased_ty(erased_alias_ty)
     }
 
@@ -241,7 +241,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
             }
 
             let p_ty = p.to_ty(tcx);
-            let erased_p_ty = self.tcx.erase_regions(p_ty);
+            let erased_p_ty = self.tcx.erase_and_anonymize_regions(p_ty);
             (erased_p_ty == erased_ty).then_some(ty::Binder::dummy(ty::OutlivesPredicate(p_ty, r)))
         }));
 

compiler/rustc_lint/src/deref_into_dyn_supertrait.rs

@@ -78,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for DerefIntoDynSupertrait {
         {
             // erase regions in self type for better diagnostic presentation
             let (self_ty, target_principal, supertrait_principal) =
-                tcx.erase_regions((self_ty, target_principal, supertrait_principal));
+                tcx.erase_and_anonymize_regions((self_ty, target_principal, supertrait_principal));
             let label2 = tcx
                 .associated_items(item.owner_id)
                 .find_by_ident_and_kind(

compiler/rustc_lint/src/for_loops_over_fallibles.rs

@@ -176,7 +176,7 @@ fn suggest_question_mark<'tcx>(
         cause,
         param_env,
         // Erase any region vids from the type, which may not be resolved
-        infcx.tcx.erase_regions(ty),
+        infcx.tcx.erase_and_anonymize_regions(ty),
         into_iterator_did,
     );
 

compiler/rustc_lint/src/types.rs

@@ -1786,7 +1786,7 @@ impl<'tcx> LateLintPass<'tcx> for VariantSizeDifferences {
     fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) {
         if let hir::ItemKind::Enum(_, _, ref enum_definition) = it.kind {
             let t = cx.tcx.type_of(it.owner_id).instantiate_identity();
-            let ty = cx.tcx.erase_regions(t);
+            let ty = cx.tcx.erase_and_anonymize_regions(t);
             let Ok(layout) = cx.layout_of(ty) else { return };
             let Variants::Multiple { tag_encoding: TagEncoding::Direct, tag, variants, .. } =
                 &layout.variants

compiler/rustc_middle/src/mir/interpret/queries.rs

@@ -41,7 +41,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let instance = ty::Instance::new_raw(def_id, args);
         let cid = GlobalId { instance, promoted: None };
         let typing_env = ty::TypingEnv::post_analysis(self, def_id);
-        let inputs = self.erase_regions(typing_env.as_query_input(cid));
+        let inputs = self.erase_and_anonymize_regions(typing_env.as_query_input(cid));
         self.eval_to_allocation_raw(inputs)
     }
 
@@ -172,8 +172,9 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> EvalToConstValueResult<'tcx> {
         // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
         // improve caching of queries.
-        let inputs =
-            self.erase_regions(typing_env.with_post_analysis_normalized(self).as_query_input(cid));
+        let inputs = self.erase_and_anonymize_regions(
+            typing_env.with_post_analysis_normalized(self).as_query_input(cid),
+        );
         if !span.is_dummy() {
             // The query doesn't know where it is being invoked, so we need to fix the span.
             self.at(span).eval_to_const_value_raw(inputs).map_err(|e| e.with_span(span))
@@ -192,8 +193,9 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> ConstToValTreeResult<'tcx> {
         // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
         // improve caching of queries.
-        let inputs =
-            self.erase_regions(typing_env.with_post_analysis_normalized(self).as_query_input(cid));
+        let inputs = self.erase_and_anonymize_regions(
+            typing_env.with_post_analysis_normalized(self).as_query_input(cid),
+        );
         debug!(?inputs);
         let res = if !span.is_dummy() {
             // The query doesn't know where it is being invoked, so we need to fix the span.

compiler/rustc_middle/src/query/mod.rs

@@ -759,9 +759,9 @@ rustc_queries! {
     }
 
     /// Erases regions from `ty` to yield a new type.
-    /// Normally you would just use `tcx.erase_regions(value)`,
+    /// Normally you would just use `tcx.erase_and_anonymize_regions(value)`,
     /// however, which uses this query as a kind of cache.
-    query erase_regions_ty(ty: Ty<'tcx>) -> Ty<'tcx> {
+    query erase_and_anonymize_regions_ty(ty: Ty<'tcx>) -> Ty<'tcx> {
         // This query is not expected to have input -- as a result, it
         // is not a good candidates for "replay" because it is essentially a
         // pure function of its input (and hence the expectation is that

compiler/rustc_middle/src/ty/abstract_const.rs

@@ -55,7 +55,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     ty::ConstKind::Unevaluated(uv) => match self.tcx.thir_abstract_const(uv.def) {
                         Err(e) => ty::Const::new_error(self.tcx, e),
                         Ok(Some(bac)) => {
-                            let args = self.tcx.erase_regions(uv.args);
+                            let args = self.tcx.erase_and_anonymize_regions(uv.args);
                             let bac = bac.instantiate(self.tcx, args);
                             return bac.fold_with(self);
                         }

compiler/rustc_middle/src/ty/erase_regions.rs

@@ -6,39 +6,39 @@ use crate::ty::{
 };
 
 pub(super) fn provide(providers: &mut Providers) {
-    *providers = Providers { erase_regions_ty, ..*providers };
+    *providers = Providers { erase_and_anonymize_regions_ty, ..*providers };
 }
 
-fn erase_regions_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
+fn erase_and_anonymize_regions_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
     // N.B., use `super_fold_with` here. If we used `fold_with`, it
-    // could invoke the `erase_regions_ty` query recursively.
-    ty.super_fold_with(&mut RegionEraserVisitor { tcx })
+    // could invoke the `erase_and_anonymize_regions_ty` query recursively.
+    ty.super_fold_with(&mut RegionEraserAndAnonymizerVisitor { tcx })
 }
 
 impl<'tcx> TyCtxt<'tcx> {
-    /// Returns an equivalent value with all free regions removed (note
-    /// that late-bound regions remain, because they are important for
-    /// subtyping, but they are anonymized and normalized as well)..
-    pub fn erase_regions<T>(self, value: T) -> T
+    /// Returns an equivalent value with all free regions removed and
+    /// bound regions anonymized. (note that bound regions are important
+    /// for subtyping and generally type equality so *cannot* be removed)
+    pub fn erase_and_anonymize_regions<T>(self, value: T) -> T
     where
         T: TypeFoldable<TyCtxt<'tcx>>,
     {
         // If there's nothing to erase or anonymize, avoid performing the query at all
         if !value.has_type_flags(TypeFlags::HAS_BINDER_VARS | TypeFlags::HAS_FREE_REGIONS) {
             return value;
         }
-        debug!("erase_regions({:?})", value);
-        let value1 = value.fold_with(&mut RegionEraserVisitor { tcx: self });
-        debug!("erase_regions = {:?}", value1);
+        debug!("erase_and_anonymize_regions({:?})", value);
+        let value1 = value.fold_with(&mut RegionEraserAndAnonymizerVisitor { tcx: self });
+        debug!("erase_and_anonymize_regions = {:?}", value1);
         value1
     }
 }
 
-struct RegionEraserVisitor<'tcx> {
+struct RegionEraserAndAnonymizerVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
-impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RegionEraserVisitor<'tcx> {
+impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RegionEraserAndAnonymizerVisitor<'tcx> {
     fn cx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
@@ -49,7 +49,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RegionEraserVisitor<'tcx> {
         } else if ty.has_infer() {
             ty.super_fold_with(self)
         } else {
-            self.tcx.erase_regions_ty(ty)
+            self.tcx.erase_and_anonymize_regions_ty(ty)
         }
     }
 

compiler/rustc_middle/src/ty/instance.rs

@@ -544,7 +544,9 @@ impl<'tcx> Instance<'tcx> {
 
         // All regions in the result of this query are erased, so it's
         // fine to erase all of the input regions.
-        tcx.resolve_instance_raw(tcx.erase_regions(typing_env.as_query_input((def_id, args))))
+        tcx.resolve_instance_raw(
+            tcx.erase_and_anonymize_regions(typing_env.as_query_input((def_id, args))),
+        )
     }
 
     pub fn expect_resolve(

compiler/rustc_middle/src/ty/layout.rs

@@ -401,7 +401,10 @@ impl<'tcx> SizeSkeleton<'tcx> {
                 match tail.kind() {
                     ty::Param(_) | ty::Alias(ty::Projection | ty::Inherent, _) => {
                         debug_assert!(tail.has_non_region_param());
-                        Ok(SizeSkeleton::Pointer { non_zero, tail: tcx.erase_regions(tail) })
+                        Ok(SizeSkeleton::Pointer {
+                            non_zero,
+                            tail: tcx.erase_and_anonymize_regions(tail),
+                        })
                     }
                     ty::Error(guar) => {
                         // Fixes ICE #124031

compiler/rustc_middle/src/ty/mod.rs

@@ -831,12 +831,12 @@ impl<'tcx> OpaqueHiddenType<'tcx> {
         //
         // We erase regions when doing this during HIR typeck.
         let this = match defining_scope_kind {
-            DefiningScopeKind::HirTypeck => tcx.erase_regions(self),
+            DefiningScopeKind::HirTypeck => tcx.erase_and_anonymize_regions(self),
             DefiningScopeKind::MirBorrowck => self,
         };
         let result = this.fold_with(&mut opaque_types::ReverseMapper::new(tcx, map, self.span));
         if cfg!(debug_assertions) && matches!(defining_scope_kind, DefiningScopeKind::HirTypeck) {
-            assert_eq!(result.ty, tcx.erase_regions(result.ty));
+            assert_eq!(result.ty, tcx.erase_and_anonymize_regions(result.ty));
         }
         result
     }