Auto merge of #145717 - BoxyUwU:erase_regions_rename, r=lcnr

rename erase_regions to erase_and_anonymize_regions

I find it consistently confusing that `erase_regions` does more than replacing regions with `'erased`. it also makes some code look real goofy to be writing manual folders to erase regions with a comment saying "we cant use erase regions" :> or code that re-calls erase_regions on types with regions already erased just to anonymize all the bound regions.

r? lcnr

idk how i feel about the name being almost twice as long now

Author: bors

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -615,7 +615,7 @@ 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

@@ -341,7 +341,7 @@ 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

@@ -1892,7 +1892,7 @@ 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))
             {
@@ -1986,7 +1986,9 @@ 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
             };
@@ -2120,7 +2122,7 @@ 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

@@ -1436,7 +1436,7 @@ 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 {
@@ -1563,7 +1563,7 @@ 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

@@ -231,7 +231,7 @@ 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