Auto merge of #135318 - compiler-errors:vtable-fixes, r=lcnr

Fix deduplication mismatches in vtables leading to upcasting unsoundness

We currently have two cases where subtleties in supertraits can trigger disagreements in the vtable layout, e.g. leading to a different vtable layout being accessed at a callsite compared to what was prepared during unsizing. Namely:

### #135315

In this example, we were not normalizing supertraits when preparing vtables. In the example,

```
trait Supertrait<T> {
    fn _print_numbers(&self, mem: &[usize; 100]) {
        println!("{mem:?}");
    }
}
impl<T> Supertrait<T> for () {}

trait Identity {
    type Selff;
}
impl<Selff> Identity for Selff {
    type Selff = Selff;
}

trait Middle<T>: Supertrait<()> + Supertrait<T> {
    fn say_hello(&self, _: &usize) {
        println!("Hello!");
    }
}
impl<T> Middle<T> for () {}

trait Trait: Middle<<() as Identity>::Selff> {}
impl Trait for () {}

fn main() {
    (&() as &dyn Trait as &dyn Middle<()>).say_hello(&0);
}
```

When we prepare `dyn Trait`, we see a supertrait of `Middle<<() as Identity>::Selff>`, which itself has two supertraits `Supertrait<()>` and `Supertrait<<() as Identity>::Selff>`. These two supertraits are identical, but they are not duplicated because we were using structural equality and *not* considering normalization. This leads to a vtable layout with two trait pointers.

When we upcast to `dyn Middle<()>`, those two supertraits are now the same, leading to a vtable layout with only one trait pointer. This leads to an offset error, and we call the wrong method.

### #135316

This one is a bit more interesting, and is the bulk of the changes in this PR. It's a bit similar, except it uses binder equality instead of normalization to make the compiler get confused about two vtable layouts. In the example,

```
trait Supertrait<T> {
    fn _print_numbers(&self, mem: &[usize; 100]) {
        println!("{mem:?}");
    }
}
impl<T> Supertrait<T> for () {}

trait Trait<T, U>: Supertrait<T> + Supertrait<U> {
    fn say_hello(&self, _: &usize) {
        println!("Hello!");
    }
}
impl<T, U> Trait<T, U> for () {}

fn main() {
    (&() as &'static dyn for<'a> Trait<&'static (), &'a ()>
        as &'static dyn Trait<&'static (), &'static ()>)
        .say_hello(&0);
}
```

When we prepare the vtable for `dyn for<'a> Trait<&'static (), &'a ()>`, we currently consider the PolyTraitRef of the vtable as the key for a supertrait. This leads two two supertraits -- `Supertrait<&'static ()>` and `for<'a> Supertrait<&'a ()>`.

However, we can upcast[^up] without offsetting the vtable from `dyn for<'a> Trait<&'static (), &'a ()>` to `dyn Trait<&'static (), &'static ()>`. This is just instantiating the principal trait ref for a specific `'a = 'static`. However, when considering those supertraits, we now have only one distinct supertrait -- `Supertrait<&'static ()>` (which is deduplicated since there are two supertraits with the same substitutions). This leads to similar offsetting issues, leading to the wrong method being called.

[^up]: I say upcast but this is a cast that is allowed on stable, since it's not changing the vtable at all, just instantiating the binder of the principal trait ref for some lifetime.

The solution here is to recognize that a vtable isn't really meaningfully higher ranked, and to just treat a vtable as corresponding to a `TraitRef` so we can do this deduplication more faithfully. That is to say, the vtable for `dyn for<'a> Tr<'a>` and `dyn Tr<'x>` are always identical, since they both would correspond to a set of free regions on an impl... Do note that `Tr<for<'a> fn(&'a ())>` and `Tr<fn(&'static ())>` are still distinct.

----

There's a bit more that can be cleaned up. In codegen, we can stop using `PolyExistentialTraitRef` basically everywhere. We can also fix SMIR to stop storing `PolyExistentialTraitRef` in its vtable allocations.

As for testing, it's difficult to actually turn this into something that can be tested with `rustc_dump_vtable`, since having multiple supertraits that are identical is a recipe for ambiguity errors. Maybe someone else is more creative with getting that attr to work, since the tests I added being run-pass tests is a bit unsatisfying. Miri also doesn't help here, since it doesn't really generate vtables that are offset by an index in the same way as codegen.

r? `@lcnr` for the vibe check? Or reassign, idk. Maybe let's talk about whether this makes sense.

<sup>(I guess an alternative would also be to not do any deduplication of vtable supertraits (or only a really conservative subset) rather than trying to normalize and deduplicate more faithfully here. Not sure if that works and is sufficient tho.)</sup>

cc `@steffahn` -- ty for the minimizations
cc `@WaffleLapkin` -- since you're overseeing the feature stabilization :3

Fixes #135315
Fixes #135316

63 files changed, 905 insertions, 728 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 3e7b81a96b6..425b2adf32a 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -6,7 +6,7 @@ use cranelift_module::*;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{AllocId, GlobalAlloc, Scalar, read_target_uint};
-use rustc_middle::ty::{Binder, ExistentialTraitRef, ScalarInt};
+use rustc_middle::ty::{ExistentialTraitRef, ScalarInt};
 
 use crate::prelude::*;
 
@@ -167,7 +167,9 @@ pub(crate) fn codegen_const_value<'tcx>(
                             &mut fx.constants_cx,
                             fx.module,
                             ty,
-                            dyn_ty.principal(),
+                            dyn_ty.principal().map(|principal| {
+                                fx.tcx.instantiate_bound_regions_with_erased(principal)
+                            }),
                         );
                         let local_data_id =
                             fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
@@ -243,7 +245,7 @@ pub(crate) fn data_id_for_vtable<'tcx>(
     cx: &mut ConstantCx,
     module: &mut dyn Module,
     ty: Ty<'tcx>,
-    trait_ref: Option<Binder<'tcx, ExistentialTraitRef<'tcx>>>,
+    trait_ref: Option<ExistentialTraitRef<'tcx>>,
 ) -> DataId {
     let alloc_id = tcx.vtable_allocation((ty, trait_ref));
     data_id_for_alloc_id(cx, module, alloc_id, Mutability::Not)
@@ -460,9 +462,15 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
                 GlobalAlloc::Memory(target_alloc) => {
                     data_id_for_alloc_id(cx, module, alloc_id, target_alloc.inner().mutability)
                 }
-                GlobalAlloc::VTable(ty, dyn_ty) => {
-                    data_id_for_vtable(tcx, cx, module, ty, dyn_ty.principal())
-                }
+                GlobalAlloc::VTable(ty, dyn_ty) => data_id_for_vtable(
+                    tcx,
+                    cx,
+                    module,
+                    ty,
+                    dyn_ty
+                        .principal()
+                        .map(|principal| tcx.instantiate_bound_regions_with_erased(principal)),
+                ),
                 GlobalAlloc::Static(def_id) => {
                     if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL)
                     {
diff --git a/compiler/rustc_codegen_cranelift/src/unsize.rs b/compiler/rustc_codegen_cranelift/src/unsize.rs
index 2843e5bbdfb..f8bbb214920 100644
--- a/compiler/rustc_codegen_cranelift/src/unsize.rs
+++ b/compiler/rustc_codegen_cranelift/src/unsize.rs
@@ -61,7 +61,12 @@ pub(crate) fn unsized_info<'tcx>(
                 old_info
             }
         }
-        (_, ty::Dynamic(data, ..)) => crate::vtable::get_vtable(fx, source, data.principal()),
+        (_, ty::Dynamic(data, ..)) => crate::vtable::get_vtable(
+            fx,
+            source,
+            data.principal()
+                .map(|principal| fx.tcx.instantiate_bound_regions_with_erased(principal)),
+        ),
         _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
     }
 }
diff --git a/compiler/rustc_codegen_cranelift/src/vtable.rs b/compiler/rustc_codegen_cranelift/src/vtable.rs
index 82b6178be9d..a460023b59c 100644
--- a/compiler/rustc_codegen_cranelift/src/vtable.rs
+++ b/compiler/rustc_codegen_cranelift/src/vtable.rs
@@ -90,7 +90,7 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
 pub(crate) fn get_vtable<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
     ty: Ty<'tcx>,
-    trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
 ) -> Value {
     let data_id = data_id_for_vtable(fx.tcx, &mut fx.constants_cx, fx.module, ty, trait_ref);
     let local_data_id = fx.module.declare_data_in_func(data_id, fx.bcx.func);
diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs
index bd5d6ba387c..20a3482aaa2 100644
--- a/compiler/rustc_codegen_gcc/src/common.rs
+++ b/compiler/rustc_codegen_gcc/src/common.rs
@@ -234,7 +234,12 @@ impl<'gcc, 'tcx> ConstCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
                     GlobalAlloc::VTable(ty, dyn_ty) => {
                         let alloc = self
                             .tcx
-                            .global_alloc(self.tcx.vtable_allocation((ty, dyn_ty.principal())))
+                            .global_alloc(self.tcx.vtable_allocation((
+                                ty,
+                                dyn_ty.principal().map(|principal| {
+                                    self.tcx.instantiate_bound_regions_with_erased(principal)
+                                }),
+                            )))
                             .unwrap_memory();
                         let init = const_alloc_to_gcc(self, alloc);
                         self.static_addr_of(init, alloc.inner().align, None)
diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs
index 30732c74eb3..570ef938dc4 100644
--- a/compiler/rustc_codegen_gcc/src/context.rs
+++ b/compiler/rustc_codegen_gcc/src/context.rs
@@ -14,7 +14,7 @@ use rustc_middle::ty::layout::{
     FnAbiError, FnAbiOf, FnAbiOfHelpers, FnAbiRequest, HasTyCtxt, HasTypingEnv, LayoutError,
     LayoutOfHelpers,
 };
-use rustc_middle::ty::{self, Instance, PolyExistentialTraitRef, Ty, TyCtxt};
+use rustc_middle::ty::{self, ExistentialTraitRef, Instance, Ty, TyCtxt};
 use rustc_session::Session;
 use rustc_span::source_map::respan;
 use rustc_span::{DUMMY_SP, Span};
@@ -90,7 +90,7 @@ pub struct CodegenCx<'gcc, 'tcx> {
     pub function_instances: RefCell<FxHashMap<Instance<'tcx>, Function<'gcc>>>,
     /// Cache generated vtables
     pub vtables:
-        RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), RValue<'gcc>>>,
+        RefCell<FxHashMap<(Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>), RValue<'gcc>>>,
 
     // TODO(antoyo): improve the SSA API to not require those.
     /// Mapping from function pointer type to indexes of on stack parameters.
@@ -401,7 +401,7 @@ impl<'gcc, 'tcx> BackendTypes for CodegenCx<'gcc, 'tcx> {
 impl<'gcc, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
     fn vtables(
         &self,
-    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<PolyExistentialTraitRef<'tcx>>), RValue<'gcc>>> {
+    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ExistentialTraitRef<'tcx>>), RValue<'gcc>>> {
         &self.vtables
     }
 
diff --git a/compiler/rustc_codegen_gcc/src/debuginfo.rs b/compiler/rustc_codegen_gcc/src/debuginfo.rs
index 4b84b1dbfd3..86d3de225f7 100644
--- a/compiler/rustc_codegen_gcc/src/debuginfo.rs
+++ b/compiler/rustc_codegen_gcc/src/debuginfo.rs
@@ -7,7 +7,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_index::bit_set::DenseBitSet;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::{self, Body, SourceScope};
-use rustc_middle::ty::{Instance, PolyExistentialTraitRef, Ty};
+use rustc_middle::ty::{ExistentialTraitRef, Instance, Ty};
 use rustc_session::config::DebugInfo;
 use rustc_span::{BytePos, Pos, SourceFile, SourceFileAndLine, Span, Symbol};
 use rustc_target::abi::Size;
@@ -214,7 +214,7 @@ impl<'gcc, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
     fn create_vtable_debuginfo(
         &self,
         _ty: Ty<'tcx>,
-        _trait_ref: Option<PolyExistentialTraitRef<'tcx>>,
+        _trait_ref: Option<ExistentialTraitRef<'tcx>>,
         _vtable: Self::Value,
     ) {
         // TODO(antoyo)
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index f8b30cb507a..8c94a46ebf3 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -314,7 +314,12 @@ impl<'ll, 'tcx> ConstCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                     GlobalAlloc::VTable(ty, dyn_ty) => {
                         let alloc = self
                             .tcx
-                            .global_alloc(self.tcx.vtable_allocation((ty, dyn_ty.principal())))
+                            .global_alloc(self.tcx.vtable_allocation((
+                                ty,
+                                dyn_ty.principal().map(|principal| {
+                                    self.tcx.instantiate_bound_regions_with_erased(principal)
+                                }),
+                            )))
                             .unwrap_memory();
                         let init = const_alloc_to_llvm(self, alloc, /*static*/ false);
                         let value = self.static_addr_of_impl(init, alloc.inner().align, None);
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 79381f35a3c..ba4fd75fb94 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -77,8 +77,7 @@ pub(crate) struct CodegenCx<'ll, 'tcx> {
     /// Cache instances of monomorphic and polymorphic items
     pub instances: RefCell<FxHashMap<Instance<'tcx>, &'ll Value>>,
     /// Cache generated vtables
-    pub vtables:
-        RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), &'ll Value>>,
+    pub vtables: RefCell<FxHashMap<(Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>), &'ll Value>>,
     /// Cache of constant strings,
     pub const_str_cache: RefCell<FxHashMap<String, &'ll Value>>,
 
@@ -663,15 +662,14 @@ impl<'ll> SimpleCx<'ll> {
 impl<'ll, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn vtables(
         &self,
-    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), &'ll Value>>
-    {
+    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>), &'ll Value>> {
         &self.vtables
     }
 
     fn apply_vcall_visibility_metadata(
         &self,
         ty: Ty<'tcx>,
-        poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+        poly_trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
         vtable: &'ll Value,
     ) {
         apply_vcall_visibility_metadata(self, ty, poly_trait_ref, vtable);
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 6eae16d8be6..3a0c7f007bd 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -13,7 +13,7 @@ use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_middle::bug;
 use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{
-    self, AdtKind, CoroutineArgsExt, Instance, PolyExistentialTraitRef, Ty, TyCtxt, Visibility,
+    self, AdtKind, CoroutineArgsExt, ExistentialTraitRef, Instance, Ty, TyCtxt, Visibility,
 };
 use rustc_session::config::{self, DebugInfo, Lto};
 use rustc_span::{DUMMY_SP, FileName, FileNameDisplayPreference, SourceFile, Symbol, hygiene};
@@ -1399,7 +1399,7 @@ pub(crate) fn build_global_var_di_node<'ll>(
 fn build_vtable_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     ty: Ty<'tcx>,
-    poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    poly_trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
 ) -> &'ll DIType {
     let tcx = cx.tcx;
 
@@ -1510,7 +1510,7 @@ fn find_vtable_behind_cast<'ll>(vtable: &'ll Value) -> &'ll Value {
 pub(crate) fn apply_vcall_visibility_metadata<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     ty: Ty<'tcx>,
-    trait_ref: Option<PolyExistentialTraitRef<'tcx>>,
+    trait_ref: Option<ExistentialTraitRef<'tcx>>,
     vtable: &'ll Value,
 ) {
     // FIXME(flip1995): The virtual function elimination optimization only works with full LTO in
@@ -1531,7 +1531,7 @@ pub(crate) fn apply_vcall_visibility_metadata<'ll, 'tcx>(
     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_def_id = trait_ref_self.def_id();
+    let trait_def_id = trait_ref_self.def_id;
     let trait_vis = cx.tcx.visibility(trait_def_id);
 
     let cgus = cx.sess().codegen_units().as_usize();
@@ -1590,7 +1590,7 @@ pub(crate) fn apply_vcall_visibility_metadata<'ll, 'tcx>(
 pub(crate) fn create_vtable_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     ty: Ty<'tcx>,
-    poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    poly_trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
     vtable: &'ll Value,
 ) {
     if cx.dbg_cx.is_none() {
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
index a37e719d43f..af1d503ad6a 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
@@ -6,7 +6,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_macros::HashStable;
 use rustc_middle::bug;
-use rustc_middle::ty::{self, PolyExistentialTraitRef, Ty, TyCtxt};
+use rustc_middle::ty::{self, ExistentialTraitRef, Ty, TyCtxt};
 
 use super::{DefinitionLocation, SmallVec, UNKNOWN_LINE_NUMBER, unknown_file_metadata};
 use crate::common::{AsCCharPtr, CodegenCx};
@@ -44,7 +44,7 @@ pub(super) enum UniqueTypeId<'tcx> {
     /// The ID for the additional wrapper struct type describing an enum variant in CPP-like mode.
     VariantStructTypeCppLikeWrapper(Ty<'tcx>, VariantIdx, private::HiddenZst),
     /// The ID of the artificial type we create for VTables.
-    VTableTy(Ty<'tcx>, Option<PolyExistentialTraitRef<'tcx>>, private::HiddenZst),
+    VTableTy(Ty<'tcx>, Option<ExistentialTraitRef<'tcx>>, private::HiddenZst),
 }
 
 impl<'tcx> UniqueTypeId<'tcx> {
@@ -88,7 +88,7 @@ impl<'tcx> UniqueTypeId<'tcx> {
     pub(crate) fn for_vtable_ty(
         tcx: TyCtxt<'tcx>,
         self_type: Ty<'tcx>,
-        implemented_trait: Option<PolyExistentialTraitRef<'tcx>>,
+        implemented_trait: Option<ExistentialTraitRef<'tcx>>,
     ) -> Self {
         assert_eq!(
             self_type,
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index 5089560784a..b1ce52667bd 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -588,7 +588,7 @@ impl<'ll, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn create_vtable_debuginfo(
         &self,
         ty: Ty<'tcx>,
-        trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+        trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
         vtable: Self::Value,
     ) {
         metadata::create_vtable_di_node(self, ty, trait_ref, vtable)
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 83a9e6e2309..ee98c8c4861 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -25,7 +25,6 @@ use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_session::Session;
 use rustc_session::config::{self, CrateType, EntryFnType, OptLevel, OutputType};
 use rustc_span::{DUMMY_SP, Symbol, sym};
-use rustc_trait_selection::infer::at::ToTrace;
 use rustc_trait_selection::infer::{BoundRegionConversionTime, TyCtxtInferExt};
 use rustc_trait_selection::traits::{ObligationCause, ObligationCtxt};
 use tracing::{debug, info};
@@ -129,14 +128,9 @@ pub fn validate_trivial_unsize<'tcx>(
                     BoundRegionConversionTime::HigherRankedType,
                     hr_source_principal,
                 );
-                let Ok(()) = ocx.eq_trace(
+                let Ok(()) = ocx.eq(
                     &ObligationCause::dummy(),
                     param_env,
-                    ToTrace::to_trace(
-                        &ObligationCause::dummy(),
-                        hr_target_principal,
-                        hr_source_principal,
-                    ),
                     target_principal,
                     source_principal,
                 ) else {
@@ -211,7 +205,12 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 old_info
             }
         }
-        (_, ty::Dynamic(data, _, _)) => meth::get_vtable(cx, source, data.principal()),
+        (_, ty::Dynamic(data, _, _)) => meth::get_vtable(
+            cx,
+            source,
+            data.principal()
+                .map(|principal| bx.tcx().instantiate_bound_regions_with_erased(principal)),
+        ),
         _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
     }
 }
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index d766ae37e5b..05175371591 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -507,7 +507,7 @@ pub enum VTableNameKind {
 pub fn compute_debuginfo_vtable_name<'tcx>(
     tcx: TyCtxt<'tcx>,
     t: Ty<'tcx>,
-    trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
     kind: VTableNameKind,
 ) -> String {
     let cpp_like_debuginfo = cpp_like_debuginfo(tcx);
@@ -530,8 +530,8 @@ pub fn compute_debuginfo_vtable_name<'tcx>(
     }
 
     if let Some(trait_ref) = trait_ref {
-        let trait_ref = tcx
-            .normalize_erasing_late_bound_regions(ty::TypingEnv::fully_monomorphized(), trait_ref);
+        let trait_ref =
+            tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), trait_ref);
         push_item_name(tcx, trait_ref.def_id, true, &mut vtable_name);
         visited.clear();
         push_generic_params_internal(tcx, trait_ref.args, &mut vtable_name, &mut visited);
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index 64cd4c38937..399c592432a 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -1,5 +1,5 @@
 use rustc_middle::bug;
-use rustc_middle::ty::{self, GenericArgKind, Ty};
+use rustc_middle::ty::{self, GenericArgKind, Ty, TyCtxt};
 use rustc_session::config::Lto;
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::callconv::FnAbi;
@@ -72,12 +72,19 @@ impl<'a, 'tcx> VirtualIndex {
 
 /// This takes a valid `self` receiver type and extracts the principal trait
 /// ref of the type. Return `None` if there is no principal trait.
-fn dyn_trait_in_self(ty: Ty<'_>) -> Option<ty::PolyExistentialTraitRef<'_>> {
+fn dyn_trait_in_self<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    ty: Ty<'tcx>,
+) -> Option<ty::ExistentialTraitRef<'tcx>> {
     for arg in ty.peel_refs().walk() {
         if let GenericArgKind::Type(ty) = arg.unpack()
             && let ty::Dynamic(data, _, _) = ty.kind()
         {
-            return data.principal();
+            // FIXME(arbitrary_self_types): This is likely broken for receivers which
+            // have a "non-self" trait objects as a generic argument.
+            return data
+                .principal()
+                .map(|principal| tcx.instantiate_bound_regions_with_erased(principal));
         }
     }
 
@@ -96,7 +103,7 @@ fn dyn_trait_in_self(ty: Ty<'_>) -> Option<ty::PolyExistentialTraitRef<'_>> {
 pub(crate) fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
     cx: &Cx,
     ty: Ty<'tcx>,
-    trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
 ) -> Cx::Value {
     let tcx = cx.tcx();
 
@@ -131,7 +138,7 @@ pub(crate) fn load_vtable<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     if bx.cx().sess().opts.unstable_opts.virtual_function_elimination
         && bx.cx().sess().lto() == Lto::Fat
     {
-        if let Some(trait_ref) = dyn_trait_in_self(ty) {
+        if let Some(trait_ref) = dyn_trait_in_self(bx.tcx(), ty) {
             let typeid = bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), trait_ref)).unwrap();
             let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
             return func;
diff --git a/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs b/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
index fe135e911fb..30d77c206a5 100644
--- a/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
@@ -2,7 +2,7 @@ use std::ops::Range;
 
 use rustc_abi::Size;
 use rustc_middle::mir;
-use rustc_middle::ty::{Instance, PolyExistentialTraitRef, Ty};
+use rustc_middle::ty::{ExistentialTraitRef, Instance, Ty};
 use rustc_span::{SourceFile, Span, Symbol};
 use rustc_target::callconv::FnAbi;
 
@@ -13,7 +13,7 @@ pub trait DebugInfoCodegenMethods<'tcx>: BackendTypes {
     fn create_vtable_debuginfo(
         &self,
         ty: Ty<'tcx>,
-        trait_ref: Option<PolyExistentialTraitRef<'tcx>>,
+        trait_ref: Option<ExistentialTraitRef<'tcx>>,
         vtable: Self::Value,
     );
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/misc.rs b/compiler/rustc_codegen_ssa/src/traits/misc.rs
index 5b33fd7ab10..4004947b464 100644
--- a/compiler/rustc_codegen_ssa/src/traits/misc.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/misc.rs
@@ -10,11 +10,11 @@ use super::BackendTypes;
 pub trait MiscCodegenMethods<'tcx>: BackendTypes {
     fn vtables(
         &self,
-    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), Self::Value>>;
+    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>), Self::Value>>;
     fn apply_vcall_visibility_metadata(
         &self,
         _ty: Ty<'tcx>,
-        _poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+        _poly_trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
         _vtable: Self::Value,
     ) {
     }
diff --git a/compiler/rustc_const_eval/src/interpret/call.rs b/compiler/rustc_const_eval/src/interpret/call.rs
index e6a34193c9d..e2e6e16d8a7 100644
--- a/compiler/rustc_const_eval/src/interpret/call.rs
+++ b/compiler/rustc_const_eval/src/interpret/call.rs
@@ -5,6 +5,7 @@ use std::borrow::Cow;
 
 use either::{Left, Right};
 use rustc_abi::{self as abi, ExternAbi, FieldIdx, Integer, VariantIdx};
+use rustc_hir::def_id::DefId;
 use rustc_middle::ty::layout::{FnAbiOf, IntegerExt, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, AdtDef, Instance, Ty, VariantDef};
 use rustc_middle::{bug, mir, span_bug};
@@ -693,25 +694,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 trace!("Virtual call dispatches to {fn_inst:#?}");
                 // We can also do the lookup based on `def_id` and `dyn_ty`, and check that that
                 // produces the same result.
-                if cfg!(debug_assertions) {
-                    let tcx = *self.tcx;
-
-                    let trait_def_id = tcx.trait_of_item(def_id).unwrap();
-                    let virtual_trait_ref =
-                        ty::TraitRef::from_method(tcx, trait_def_id, instance.args);
-                    let existential_trait_ref =
-                        ty::ExistentialTraitRef::erase_self_ty(tcx, virtual_trait_ref);
-                    let concrete_trait_ref = existential_trait_ref.with_self_ty(tcx, dyn_ty);
-
-                    let concrete_method = Instance::expect_resolve_for_vtable(
-                        tcx,
-                        self.typing_env,
-                        def_id,
-                        instance.args.rebase_onto(tcx, trait_def_id, concrete_trait_ref.args),
-                        self.cur_span(),
-                    );
-                    assert_eq!(fn_inst, concrete_method);
-                }
+                self.assert_virtual_instance_matches_concrete(dyn_ty, def_id, instance, fn_inst);
 
                 // Adjust receiver argument. Layout can be any (thin) ptr.
                 let receiver_ty = Ty::new_mut_ptr(self.tcx.tcx, dyn_ty);
@@ -744,6 +727,30 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         }
     }
 
+    fn assert_virtual_instance_matches_concrete(
+        &self,
+        dyn_ty: Ty<'tcx>,
+        def_id: DefId,
+        virtual_instance: ty::Instance<'tcx>,
+        concrete_instance: ty::Instance<'tcx>,
+    ) {
+        let tcx = *self.tcx;
+
+        let trait_def_id = tcx.trait_of_item(def_id).unwrap();
+        let virtual_trait_ref = ty::TraitRef::from_method(tcx, trait_def_id, virtual_instance.args);
+        let existential_trait_ref = ty::ExistentialTraitRef::erase_self_ty(tcx, virtual_trait_ref);
+        let concrete_trait_ref = existential_trait_ref.with_self_ty(tcx, dyn_ty);
+
+        let concrete_method = Instance::expect_resolve_for_vtable(
+            tcx,
+            self.typing_env,
+            def_id,
+            virtual_instance.args.rebase_onto(tcx, trait_def_id, concrete_trait_ref.args),
+            self.cur_span(),
+        );
+        assert_eq!(concrete_instance, concrete_method);
+    }
+
     /// Initiate a tail call to this function -- popping the current stack frame, pushing the new
     /// stack frame and initializing the arguments.
     pub(super) fn init_fn_tail_call(
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index ef3e96784ce..e110c155da0 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -414,36 +414,33 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
                 // Sanity-check that `supertrait_vtable_slot` in this type's vtable indeed produces
                 // our destination trait.
-                if cfg!(debug_assertions) {
-                    let vptr_entry_idx =
-                        self.tcx.supertrait_vtable_slot((src_pointee_ty, dest_pointee_ty));
-                    let vtable_entries = self.vtable_entries(data_a.principal(), ty);
-                    if let Some(entry_idx) = vptr_entry_idx {
-                        let Some(&ty::VtblEntry::TraitVPtr(upcast_trait_ref)) =
-                            vtable_entries.get(entry_idx)
-                        else {
-                            span_bug!(
-                                self.cur_span(),
-                                "invalid vtable entry index in {} -> {} upcast",
-                                src_pointee_ty,
-                                dest_pointee_ty
-                            );
-                        };
-                        let erased_trait_ref = upcast_trait_ref
-                            .map_bound(|r| ty::ExistentialTraitRef::erase_self_ty(*self.tcx, r));
-                        assert!(
-                            data_b
-                                .principal()
-                                .is_some_and(|b| self.eq_in_param_env(erased_trait_ref, b))
+                let vptr_entry_idx =
+                    self.tcx.supertrait_vtable_slot((src_pointee_ty, dest_pointee_ty));
+                let vtable_entries = self.vtable_entries(data_a.principal(), ty);
+                if let Some(entry_idx) = vptr_entry_idx {
+                    let Some(&ty::VtblEntry::TraitVPtr(upcast_trait_ref)) =
+                        vtable_entries.get(entry_idx)
+                    else {
+                        span_bug!(
+                            self.cur_span(),
+                            "invalid vtable entry index in {} -> {} upcast",
+                            src_pointee_ty,
+                            dest_pointee_ty
                         );
-                    } else {
-                        // In this case codegen would keep using the old vtable. We don't want to do
-                        // that as it has the wrong trait. The reason codegen can do this is that
-                        // one vtable is a prefix of the other, so we double-check that.
-                        let vtable_entries_b = self.vtable_entries(data_b.principal(), ty);
-                        assert!(&vtable_entries[..vtable_entries_b.len()] == vtable_entries_b);
                     };
-                }
+                    let erased_trait_ref =
+                        ty::ExistentialTraitRef::erase_self_ty(*self.tcx, upcast_trait_ref);
+                    assert!(data_b.principal().is_some_and(|b| self.eq_in_param_env(
+                        erased_trait_ref,
+                        self.tcx.instantiate_bound_regions_with_erased(b)
+                    )));
+                } else {
+                    // In this case codegen would keep using the old vtable. We don't want to do
+                    // that as it has the wrong trait. The reason codegen can do this is that
+                    // one vtable is a prefix of the other, so we double-check that.
+                    let vtable_entries_b = self.vtable_entries(data_b.principal(), ty);
+                    assert!(&vtable_entries[..vtable_entries_b.len()] == vtable_entries_b);
+                };
 
                 // Get the destination trait vtable and return that.
                 let new_vptr = self.get_vtable_ptr(ty, data_b)?;
diff --git a/compiler/rustc_const_eval/src/interpret/traits.rs b/compiler/rustc_const_eval/src/interpret/traits.rs
index af8d618b6b5..4cfaacebfcd 100644
--- a/compiler/rustc_const_eval/src/interpret/traits.rs
+++ b/compiler/rustc_const_eval/src/interpret/traits.rs
@@ -54,7 +54,8 @@ 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(trait_ref);
+            let trait_ref =
+                self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
             self.tcx.vtable_entries(trait_ref)
         } else {
             TyCtxt::COMMON_VTABLE_ENTRIES
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 17433eed9e7..684fc5e37e0 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -1136,7 +1136,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
     rustc_attr!(
         TEST, rustc_dump_vtable, Normal, template!(Word),
-        WarnFollowing, EncodeCrossCrate::Yes
+        WarnFollowing, EncodeCrossCrate::No
     ),
     rustc_attr!(
         TEST, rustc_dummy, Normal, template!(Word /* doesn't matter*/),
diff --git a/compiler/rustc_hir_analysis/src/collect/dump.rs b/compiler/rustc_hir_analysis/src/collect/dump.rs
index f1022d95753..4a508fc0cf6 100644
--- a/compiler/rustc_hir_analysis/src/collect/dump.rs
+++ b/compiler/rustc_hir_analysis/src/collect/dump.rs
@@ -1,7 +1,8 @@
+use rustc_hir as hir;
 use rustc_hir::def_id::{CRATE_DEF_ID, LocalDefId};
 use rustc_hir::intravisit;
 use rustc_middle::hir::nested_filter;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_span::sym;
 
 pub(crate) fn opaque_hidden_types(tcx: TyCtxt<'_>) {
@@ -87,3 +88,82 @@ pub(crate) fn def_parents(tcx: TyCtxt<'_>) {
         }
     }
 }
+
+pub(crate) fn vtables<'tcx>(tcx: TyCtxt<'tcx>) {
+    for id in tcx.hir().items() {
+        let def_id = id.owner_id.def_id;
+
+        let Some(attr) = tcx.get_attr(def_id, sym::rustc_dump_vtable) else {
+            continue;
+        };
+
+        let vtable_entries = match tcx.hir().item(id).kind {
+            hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => {
+                let trait_ref = tcx.impl_trait_ref(def_id).unwrap().instantiate_identity();
+                if trait_ref.has_non_region_param() {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to non-generic impl",
+                    );
+                    continue;
+                }
+                if !tcx.is_dyn_compatible(trait_ref.def_id) {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to dyn-compatible trait",
+                    );
+                    continue;
+                }
+                let Ok(trait_ref) = tcx
+                    .try_normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), trait_ref)
+                else {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` applied to impl header that cannot be normalized",
+                    );
+                    continue;
+                };
+                tcx.vtable_entries(trait_ref)
+            }
+            hir::ItemKind::TyAlias(_, _) => {
+                let ty = tcx.type_of(def_id).instantiate_identity();
+                if ty.has_non_region_param() {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to non-generic type",
+                    );
+                    continue;
+                }
+                let Ok(ty) =
+                    tcx.try_normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), ty)
+                else {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` applied to type alias that cannot be normalized",
+                    );
+                    continue;
+                };
+                let ty::Dynamic(data, _, _) = *ty.kind() else {
+                    tcx.dcx().span_err(attr.span, "`rustc_dump_vtable` to type alias of dyn type");
+                    continue;
+                };
+                if let Some(principal) = data.principal() {
+                    tcx.vtable_entries(
+                        tcx.instantiate_bound_regions_with_erased(principal).with_self_ty(tcx, ty),
+                    )
+                } else {
+                    TyCtxt::COMMON_VTABLE_ENTRIES
+                }
+            }
+            _ => {
+                tcx.dcx().span_err(
+                    attr.span,
+                    "`rustc_dump_vtable` only applies to impl, or type alias of dyn type",
+                );
+                continue;
+            }
+        };
+
+        tcx.dcx().span_err(tcx.def_span(def_id), format!("vtable entries: {vtable_entries:#?}"));
+    }
+}
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index bc7d4365eee..03dd0cccf75 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -152,11 +152,14 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
     });
 
     if tcx.features().rustc_attrs() {
-        tcx.sess.time("outlives_dumping", || outlives::dump::inferred_outlives(tcx));
-        tcx.sess.time("variance_dumping", || variance::dump::variances(tcx));
-        collect::dump::opaque_hidden_types(tcx);
-        collect::dump::predicates_and_item_bounds(tcx);
-        collect::dump::def_parents(tcx);
+        tcx.sess.time("dumping_rustc_attr_data", || {
+            outlives::dump::inferred_outlives(tcx);
+            variance::dump::variances(tcx);
+            collect::dump::opaque_hidden_types(tcx);
+            collect::dump::predicates_and_item_bounds(tcx);
+            collect::dump::def_parents(tcx);
+            collect::dump::vtables(tcx);
+        });
     }
 
     // Make sure we evaluate all static and (non-associated) const items, even if unused.
diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs
index 12e2bbc968f..ad15b764bcc 100644
--- a/compiler/rustc_infer/src/infer/at.rs
+++ b/compiler/rustc_infer/src/infer/at.rs
@@ -402,6 +402,18 @@ impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialTraitRef<'tcx> {
     }
 }
 
+impl<'tcx> ToTrace<'tcx> for ty::ExistentialTraitRef<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
+        TypeTrace {
+            cause: cause.clone(),
+            values: ValuePairs::ExistentialTraitRef(ExpectedFound::new(
+                ty::Binder::dummy(a),
+                ty::Binder::dummy(b),
+            )),
+        }
+    }
+}
+
 impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialProjection<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
@@ -410,3 +422,15 @@ impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialProjection<'tcx> {
         }
     }
 }
+
+impl<'tcx> ToTrace<'tcx> for ty::ExistentialProjection<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
+        TypeTrace {
+            cause: cause.clone(),
+            values: ValuePairs::ExistentialProjection(ExpectedFound::new(
+                ty::Binder::dummy(a),
+                ty::Binder::dummy(b),
+            )),
+        }
+    }
+}
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 241bc35857a..0b91c023cfc 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -26,7 +26,6 @@ use rustc_parse::{
 };
 use rustc_passes::{abi_test, input_stats, layout_test};
 use rustc_resolve::Resolver;
-use rustc_session::code_stats::VTableSizeInfo;
 use rustc_session::config::{CrateType, Input, OutFileName, OutputFilenames, OutputType};
 use rustc_session::cstore::Untracked;
 use rustc_session::output::{collect_crate_types, filename_for_input, find_crate_name};
@@ -989,90 +988,6 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) {
         // we will fail to emit overlap diagnostics. Thus we invoke it here unconditionally.
         let _ = tcx.all_diagnostic_items(());
     });
-
-    if sess.opts.unstable_opts.print_vtable_sizes {
-        let traits = tcx.traits(LOCAL_CRATE);
-
-        for &tr in traits {
-            if !tcx.is_dyn_compatible(tr) {
-                continue;
-            }
-
-            let name = ty::print::with_no_trimmed_paths!(tcx.def_path_str(tr));
-
-            let mut first_dsa = true;
-
-            // Number of vtable entries, if we didn't have upcasting
-            let mut entries_ignoring_upcasting = 0;
-            // Number of vtable entries needed solely for upcasting
-            let mut entries_for_upcasting = 0;
-
-            let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(tcx, tr));
-
-            // A slightly edited version of the code in
-            // `rustc_trait_selection::traits::vtable::vtable_entries`, that works without self
-            // type and just counts number of entries.
-            //
-            // Note that this is technically wrong, for traits which have associated types in
-            // supertraits:
-            //
-            //   trait A: AsRef<Self::T> + AsRef<()> { type T; }
-            //
-            // Without self type we can't normalize `Self::T`, so we can't know if `AsRef<Self::T>`
-            // and `AsRef<()>` are the same trait, thus we assume that those are different, and
-            // potentially over-estimate how many vtable entries there are.
-            //
-            // Similarly this is wrong for traits that have methods with possibly-impossible bounds.
-            // For example:
-            //
-            //   trait B<T> { fn f(&self) where T: Copy; }
-            //
-            // Here `dyn B<u8>` will have 4 entries, while `dyn B<String>` will only have 3.
-            // However, since we don't know `T`, we can't know if `T: Copy` holds or not,
-            // thus we lean on the bigger side and say it has 4 entries.
-            traits::vtable::prepare_vtable_segments(tcx, trait_ref, |segment| {
-                match segment {
-                    traits::vtable::VtblSegment::MetadataDSA => {
-                        // If this is the first dsa, it would be included either way,
-                        // otherwise it's needed for upcasting
-                        if std::mem::take(&mut first_dsa) {
-                            entries_ignoring_upcasting += 3;
-                        } else {
-                            entries_for_upcasting += 3;
-                        }
-                    }
-
-                    traits::vtable::VtblSegment::TraitOwnEntries { trait_ref, emit_vptr } => {
-                        // Lookup the shape of vtable for the trait.
-                        let own_existential_entries =
-                            tcx.own_existential_vtable_entries(trait_ref.def_id());
-
-                        // The original code here ignores the method if its predicates are
-                        // impossible. We can't really do that as, for example, all not trivial
-                        // bounds on generic parameters are impossible (since we don't know the
-                        // parameters...), see the comment above.
-                        entries_ignoring_upcasting += own_existential_entries.len();
-
-                        if emit_vptr {
-                            entries_for_upcasting += 1;
-                        }
-                    }
-                }
-
-                std::ops::ControlFlow::Continue::<std::convert::Infallible>(())
-            });
-
-            sess.code_stats.record_vtable_size(tr, &name, VTableSizeInfo {
-                trait_name: name.clone(),
-                entries: entries_ignoring_upcasting + entries_for_upcasting,
-                entries_ignoring_upcasting,
-                entries_for_upcasting,
-                upcasting_cost_percent: entries_for_upcasting as f64
-                    / entries_ignoring_upcasting as f64
-                    * 100.,
-            })
-        }
-    }
 }
 
 /// Check for the `#[rustc_error]` annotation, which forces an error in codegen. This is used
@@ -1153,12 +1068,6 @@ pub(crate) fn start_codegen<'tcx>(
         tcx.sess.code_stats.print_type_sizes();
     }
 
-    if tcx.sess.opts.unstable_opts.print_vtable_sizes {
-        let crate_name = tcx.crate_name(LOCAL_CRATE);
-
-        tcx.sess.code_stats.print_vtable_sizes(crate_name);
-    }
-
     codegen
 }
 
diff --git a/compiler/rustc_middle/src/query/keys.rs b/compiler/rustc_middle/src/query/keys.rs
index f7090fa69e2..949d8303385 100644
--- a/compiler/rustc_middle/src/query/keys.rs
+++ b/compiler/rustc_middle/src/query/keys.rs
@@ -95,7 +95,7 @@ impl<'tcx> Key for mir::interpret::GlobalId<'tcx> {
     }
 }
 
-impl<'tcx> Key for (Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>) {
+impl<'tcx> Key for (Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>) {
     type Cache<V> = DefaultCache<Self, V>;
 
     fn default_span(&self, _: TyCtxt<'_>) -> Span {
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 560e3bf3ade..41e9858030c 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1437,9 +1437,9 @@ rustc_queries! {
         desc { |tcx| "finding all existential vtable entries for trait `{}`", tcx.def_path_str(key) }
     }
 
-    query vtable_entries(key: ty::PolyTraitRef<'tcx>)
+    query vtable_entries(key: ty::TraitRef<'tcx>)
                         -> &'tcx [ty::VtblEntry<'tcx>] {
-        desc { |tcx| "finding all vtable entries for trait `{}`", tcx.def_path_str(key.def_id()) }
+        desc { |tcx| "finding all vtable entries for trait `{}`", tcx.def_path_str(key.def_id) }
     }
 
     query first_method_vtable_slot(key: ty::TraitRef<'tcx>) -> usize {
@@ -1451,7 +1451,7 @@ rustc_queries! {
             key.1, key.0 }
     }
 
-    query vtable_allocation(key: (Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>)) -> mir::interpret::AllocId {
+    query vtable_allocation(key: (Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>)) -> mir::interpret::AllocId {
         desc { |tcx| "vtable const allocation for <{} as {}>",
             key.0,
             key.1.map(|trait_ref| format!("{trait_ref}")).unwrap_or("_".to_owned())
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index b212992bd2d..3ced64b5b80 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -858,7 +858,12 @@ where
                     }
 
                     let mk_dyn_vtable = |principal: Option<ty::PolyExistentialTraitRef<'tcx>>| {
-                        let min_count = ty::vtable_min_entries(tcx, principal);
+                        let min_count = ty::vtable_min_entries(
+                            tcx,
+                            principal.map(|principal| {
+                                tcx.instantiate_bound_regions_with_erased(principal)
+                            }),
+                        );
                         Ty::new_imm_ref(
                             tcx,
                             tcx.lifetimes.re_static,
diff --git a/compiler/rustc_middle/src/ty/vtable.rs b/compiler/rustc_middle/src/ty/vtable.rs
index 455bd16ff8c..6c9e0e7c0eb 100644
--- a/compiler/rustc_middle/src/ty/vtable.rs
+++ b/compiler/rustc_middle/src/ty/vtable.rs
@@ -7,7 +7,7 @@ use rustc_type_ir::elaborate;
 use crate::mir::interpret::{
     AllocId, AllocInit, Allocation, CTFE_ALLOC_SALT, Pointer, Scalar, alloc_range,
 };
-use crate::ty::{self, Instance, PolyTraitRef, Ty, TyCtxt};
+use crate::ty::{self, Instance, TraitRef, Ty, TyCtxt};
 
 #[derive(Clone, Copy, PartialEq, HashStable)]
 pub enum VtblEntry<'tcx> {
@@ -22,7 +22,7 @@ pub enum VtblEntry<'tcx> {
     /// dispatchable associated function
     Method(Instance<'tcx>),
     /// pointer to a separate supertrait vtable, can be used by trait upcasting coercion
-    TraitVPtr(PolyTraitRef<'tcx>),
+    TraitVPtr(TraitRef<'tcx>),
 }
 
 impl<'tcx> fmt::Debug for VtblEntry<'tcx> {
@@ -59,7 +59,7 @@ pub const COMMON_VTABLE_ENTRIES_ALIGN: usize = 2;
 // function is an accurate approximation. We verify this when actually computing the vtable below.
 pub(crate) fn vtable_min_entries<'tcx>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+    trait_ref: Option<ty::ExistentialTraitRef<'tcx>>,
 ) -> usize {
     let mut count = TyCtxt::COMMON_VTABLE_ENTRIES.len();
     let Some(trait_ref) = trait_ref else {
@@ -67,7 +67,7 @@ pub(crate) fn vtable_min_entries<'tcx>(
     };
 
     // This includes self in supertraits.
-    for def_id in elaborate::supertrait_def_ids(tcx, trait_ref.def_id()) {
+    for def_id in elaborate::supertrait_def_ids(tcx, trait_ref.def_id) {
         count += tcx.own_existential_vtable_entries(def_id).len();
     }
 
@@ -83,7 +83,7 @@ pub(crate) fn vtable_min_entries<'tcx>(
 /// initial contents.)
 pub(super) fn vtable_allocation_provider<'tcx>(
     tcx: TyCtxt<'tcx>,
-    key: (Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>),
+    key: (Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>),
 ) -> AllocId {
     let (ty, poly_trait_ref) = key;
 
@@ -118,7 +118,7 @@ pub(super) fn vtable_allocation_provider<'tcx>(
 
     for (idx, entry) in vtable_entries.iter().enumerate() {
         let idx: u64 = u64::try_from(idx).unwrap();
-        let scalar = match entry {
+        let scalar = match *entry {
             VtblEntry::MetadataDropInPlace => {
                 if ty.needs_drop(tcx, ty::TypingEnv::fully_monomorphized()) {
                     let instance = ty::Instance::resolve_drop_in_place(tcx, ty);
@@ -134,13 +134,12 @@ pub(super) fn vtable_allocation_provider<'tcx>(
             VtblEntry::Vacant => continue,
             VtblEntry::Method(instance) => {
                 // Prepare the fn ptr we write into the vtable.
-                let fn_alloc_id = tcx.reserve_and_set_fn_alloc(*instance, CTFE_ALLOC_SALT);
+                let fn_alloc_id = tcx.reserve_and_set_fn_alloc(instance, CTFE_ALLOC_SALT);
                 let fn_ptr = Pointer::from(fn_alloc_id);
                 Scalar::from_pointer(fn_ptr, &tcx)
             }
             VtblEntry::TraitVPtr(trait_ref) => {
-                let super_trait_ref = trait_ref
-                    .map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+                let super_trait_ref = ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref);
                 let supertrait_alloc_id = tcx.vtable_allocation((ty, Some(super_trait_ref)));
                 let vptr = Pointer::from(supertrait_alloc_id);
                 Scalar::from_pointer(vptr, &tcx)
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index d53848f7461..150594ab94d 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -1138,11 +1138,12 @@ fn create_mono_items_for_vtable_methods<'tcx>(
         bug!("create_mono_items_for_vtable_methods: {trait_ty:?} not a trait type");
     };
     if let Some(principal) = trait_ty.principal() {
-        let poly_trait_ref = principal.with_self_ty(tcx, impl_ty);
-        assert!(!poly_trait_ref.has_escaping_bound_vars());
+        let trait_ref =
+            tcx.instantiate_bound_regions_with_erased(principal.with_self_ty(tcx, impl_ty));
+        assert!(!trait_ref.has_escaping_bound_vars());
 
         // Walk all methods of the trait, including those of its supertraits
-        let entries = tcx.vtable_entries(poly_trait_ref);
+        let entries = tcx.vtable_entries(trait_ref);
         debug!(?entries);
         let methods = entries
             .iter()
@@ -1197,7 +1198,12 @@ fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoIt
             }
         }
         GlobalAlloc::VTable(ty, dyn_ty) => {
-            let alloc_id = tcx.vtable_allocation((ty, dyn_ty.principal()));
+            let alloc_id = tcx.vtable_allocation((
+                ty,
+                dyn_ty
+                    .principal()
+                    .map(|principal| tcx.instantiate_bound_regions_with_erased(principal)),
+            ));
             collect_alloc(tcx, alloc_id, output)
         }
     }
diff --git a/compiler/rustc_session/src/code_stats.rs b/compiler/rustc_session/src/code_stats.rs
index f3c21992784..b4597ae2515 100644
--- a/compiler/rustc_session/src/code_stats.rs
+++ b/compiler/rustc_session/src/code_stats.rs
@@ -1,10 +1,9 @@
 use std::cmp;
 
 use rustc_abi::{Align, Size};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lock;
 use rustc_span::Symbol;
-use rustc_span::def_id::DefId;
 
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct VariantInfo {
@@ -71,29 +70,9 @@ pub struct TypeSizeInfo {
     pub variants: Vec<VariantInfo>,
 }
 
-pub struct VTableSizeInfo {
-    pub trait_name: String,
-
-    /// Number of entries in a vtable with the current algorithm
-    /// (i.e. with upcasting).
-    pub entries: usize,
-
-    /// Number of entries in a vtable, as-if we did not have trait upcasting.
-    pub entries_ignoring_upcasting: usize,
-
-    /// Number of entries in a vtable needed solely for upcasting
-    /// (i.e. `entries - entries_ignoring_upcasting`).
-    pub entries_for_upcasting: usize,
-
-    /// Cost of having upcasting in % relative to the number of entries without
-    /// upcasting (i.e. `entries_for_upcasting / entries_ignoring_upcasting * 100%`).
-    pub upcasting_cost_percent: f64,
-}
-
 #[derive(Default)]
 pub struct CodeStats {
     type_sizes: Lock<FxHashSet<TypeSizeInfo>>,
-    vtable_sizes: Lock<FxHashMap<DefId, VTableSizeInfo>>,
 }
 
 impl CodeStats {
@@ -127,14 +106,6 @@ impl CodeStats {
         self.type_sizes.borrow_mut().insert(info);
     }
 
-    pub fn record_vtable_size(&self, trait_did: DefId, trait_name: &str, info: VTableSizeInfo) {
-        let prev = self.vtable_sizes.lock().insert(trait_did, info);
-        assert!(
-            prev.is_none(),
-            "size of vtable for `{trait_name}` ({trait_did:?}) is already recorded"
-        );
-    }
-
     pub fn print_type_sizes(&self) {
         let type_sizes = self.type_sizes.borrow();
         // We will soon sort, so the initial order does not matter.
@@ -238,33 +209,4 @@ impl CodeStats {
             }
         }
     }
-
-    pub fn print_vtable_sizes(&self, crate_name: Symbol) {
-        // We will soon sort, so the initial order does not matter.
-        #[allow(rustc::potential_query_instability)]
-        let mut infos =
-            std::mem::take(&mut *self.vtable_sizes.lock()).into_values().collect::<Vec<_>>();
-
-        // Primary sort: cost % in reverse order (from largest to smallest)
-        // Secondary sort: trait_name
-        infos.sort_by(|a, b| {
-            a.upcasting_cost_percent
-                .total_cmp(&b.upcasting_cost_percent)
-                .reverse()
-                .then_with(|| a.trait_name.cmp(&b.trait_name))
-        });
-
-        for VTableSizeInfo {
-            trait_name,
-            entries,
-            entries_ignoring_upcasting,
-            entries_for_upcasting,
-            upcasting_cost_percent,
-        } in infos
-        {
-            println!(
-                r#"print-vtable-sizes {{ "crate_name": "{crate_name}", "trait_name": "{trait_name}", "entries": "{entries}", "entries_ignoring_upcasting": "{entries_ignoring_upcasting}", "entries_for_upcasting": "{entries_for_upcasting}", "upcasting_cost_percent": "{upcasting_cost_percent}" }}"#
-            );
-        }
-    }
 }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index c7af40a8ad4..e3236350cad 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -2034,8 +2034,6 @@ options! {
          Note that this overwrites the effect `-Clink-dead-code` has on collection!"),
     print_type_sizes: bool = (false, parse_bool, [UNTRACKED],
         "print layout information for each type encountered (default: no)"),
-    print_vtable_sizes: bool = (false, parse_bool, [UNTRACKED],
-        "print size comparison between old and new vtable layouts (default: no)"),
     proc_macro_backtrace: bool = (false, parse_bool, [UNTRACKED],
          "show backtraces for panics during proc-macro execution (default: no)"),
     proc_macro_execution_strategy: ProcMacroExecutionStrategy = (ProcMacroExecutionStrategy::SameThread,
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index 8d4e55dc036..cdc56782a26 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -747,7 +747,9 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         let tcx = tables.tcx;
         let alloc_id = tables.tcx.vtable_allocation((
             ty.internal(&mut *tables, tcx),
-            trait_ref.internal(&mut *tables, tcx),
+            trait_ref
+                .internal(&mut *tables, tcx)
+                .map(|principal| tcx.instantiate_bound_regions_with_erased(principal)),
         ));
         Some(alloc_id.stable(&mut *tables))
     }
diff --git a/compiler/rustc_symbol_mangling/src/lib.rs b/compiler/rustc_symbol_mangling/src/lib.rs
index 5c5ab435dbd..4312c82815c 100644
--- a/compiler/rustc_symbol_mangling/src/lib.rs
+++ b/compiler/rustc_symbol_mangling/src/lib.rs
@@ -151,7 +151,7 @@ fn symbol_name_provider<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> ty
 
 pub fn typeid_for_trait_ref<'tcx>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: ty::PolyExistentialTraitRef<'tcx>,
+    trait_ref: ty::ExistentialTraitRef<'tcx>,
 ) -> String {
     v0::mangle_typeid_for_trait_ref(tcx, trait_ref)
 }
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs
index 5b3272feecd..7b040a8b2c4 100644
--- a/compiler/rustc_symbol_mangling/src/v0.rs
+++ b/compiler/rustc_symbol_mangling/src/v0.rs
@@ -72,7 +72,7 @@ pub(super) fn mangle<'tcx>(
 
 pub(super) fn mangle_typeid_for_trait_ref<'tcx>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: ty::PolyExistentialTraitRef<'tcx>,
+    trait_ref: ty::ExistentialTraitRef<'tcx>,
 ) -> String {
     // FIXME(flip1995): See comment in `mangle_typeid_for_fnabi`.
     let mut cx = SymbolMangler {
@@ -84,7 +84,7 @@ pub(super) fn mangle_typeid_for_trait_ref<'tcx>(
         binders: vec![],
         out: String::new(),
     };
-    cx.print_def_path(trait_ref.def_id(), &[]).unwrap();
+    cx.print_def_path(trait_ref.def_id, &[]).unwrap();
     std::mem::take(&mut cx.out)
 }
 
diff --git a/compiler/rustc_trait_selection/messages.ftl b/compiler/rustc_trait_selection/messages.ftl
index 7c72318b4d7..055a3edcc32 100644
--- a/compiler/rustc_trait_selection/messages.ftl
+++ b/compiler/rustc_trait_selection/messages.ftl
@@ -148,8 +148,6 @@ trait_selection_dtcs_has_req_note = the used `impl` has a `'static` requirement
 trait_selection_dtcs_introduces_requirement = calling this method introduces the `impl`'s `'static` requirement
 trait_selection_dtcs_suggestion = consider relaxing the implicit `'static` requirement
 
-trait_selection_dump_vtable_entries = vtable entries for `{$trait_ref}`: {$entries}
-
 trait_selection_empty_on_clause_in_rustc_on_unimplemented = empty `on`-clause in `#[rustc_on_unimplemented]`
     .label = empty on-clause here
 
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs
index c8672b9dbd2..c5ab8a71c78 100644
--- a/compiler/rustc_trait_selection/src/errors.rs
+++ b/compiler/rustc_trait_selection/src/errors.rs
@@ -12,7 +12,7 @@ use rustc_hir::intravisit::{Visitor, VisitorExt, walk_ty};
 use rustc_hir::{self as hir, AmbigArg, FnRetTy, GenericParamKind, Node};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_middle::ty::print::{PrintTraitRefExt as _, TraitRefPrintOnlyTraitPath};
-use rustc_middle::ty::{self, Binder, ClosureKind, FnSig, PolyTraitRef, Region, Ty, TyCtxt};
+use rustc_middle::ty::{self, Binder, ClosureKind, FnSig, Region, Ty, TyCtxt};
 use rustc_span::{BytePos, Ident, Span, Symbol, kw};
 
 use crate::error_reporting::infer::ObligationCauseAsDiagArg;
@@ -23,15 +23,6 @@ use crate::fluent_generated as fluent;
 pub mod note_and_explain;
 
 #[derive(Diagnostic)]
-#[diag(trait_selection_dump_vtable_entries)]
-pub struct DumpVTableEntries<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub trait_ref: PolyTraitRef<'a>,
-    pub entries: String,
-}
-
-#[derive(Diagnostic)]
 #[diag(trait_selection_unable_to_construct_constant_value)]
 pub struct UnableToConstructConstantValue<'a> {
     #[primary_span]
diff --git a/compiler/rustc_trait_selection/src/traits/vtable.rs b/compiler/rustc_trait_selection/src/traits/vtable.rs
index b5bc8364c7b..000e6a765d3 100644
--- a/compiler/rustc_trait_selection/src/traits/vtable.rs
+++ b/compiler/rustc_trait_selection/src/traits/vtable.rs
@@ -2,26 +2,22 @@ use std::fmt::Debug;
 use std::ops::ControlFlow;
 
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::at::ToTrace;
-use rustc_infer::infer::{BoundRegionConversionTime, TyCtxtInferExt};
-use rustc_infer::traits::ObligationCause;
 use rustc_infer::traits::util::PredicateSet;
 use rustc_middle::bug;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{
     self, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeVisitableExt, Upcast, VtblEntry,
 };
-use rustc_span::{DUMMY_SP, Span, sym};
+use rustc_span::DUMMY_SP;
 use smallvec::{SmallVec, smallvec};
 use tracing::debug;
 
-use crate::errors::DumpVTableEntries;
-use crate::traits::{ObligationCtxt, impossible_predicates, is_vtable_safe_method};
+use crate::traits::{impossible_predicates, is_vtable_safe_method};
 
 #[derive(Clone, Debug)]
 pub enum VtblSegment<'tcx> {
     MetadataDSA,
-    TraitOwnEntries { trait_ref: ty::PolyTraitRef<'tcx>, emit_vptr: bool },
+    TraitOwnEntries { trait_ref: ty::TraitRef<'tcx>, emit_vptr: bool },
 }
 
 /// Prepare the segments for a vtable
@@ -29,7 +25,7 @@ pub enum VtblSegment<'tcx> {
 // about our `Self` type here.
 pub fn prepare_vtable_segments<'tcx, T>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: ty::PolyTraitRef<'tcx>,
+    trait_ref: ty::TraitRef<'tcx>,
     segment_visitor: impl FnMut(VtblSegment<'tcx>) -> ControlFlow<T>,
 ) -> Option<T> {
     prepare_vtable_segments_inner(tcx, trait_ref, segment_visitor).break_value()
@@ -39,7 +35,7 @@ pub fn prepare_vtable_segments<'tcx, T>(
 /// such that we can use `?` in the body.
 fn prepare_vtable_segments_inner<'tcx, T>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: ty::PolyTraitRef<'tcx>,
+    trait_ref: ty::TraitRef<'tcx>,
     mut segment_visitor: impl FnMut(VtblSegment<'tcx>) -> ControlFlow<T>,
 ) -> ControlFlow<T> {
     // The following constraints holds for the final arrangement.
@@ -92,7 +88,7 @@ fn prepare_vtable_segments_inner<'tcx, T>(
     let mut emit_vptr_on_new_entry = false;
     let mut visited = PredicateSet::new(tcx);
     let predicate = trait_ref.upcast(tcx);
-    let mut stack: SmallVec<[(ty::PolyTraitRef<'tcx>, _, _); 5]> =
+    let mut stack: SmallVec<[(ty::TraitRef<'tcx>, _, _); 5]> =
         smallvec![(trait_ref, emit_vptr_on_new_entry, maybe_iter(None))];
     visited.insert(predicate);
 
@@ -125,10 +121,18 @@ fn prepare_vtable_segments_inner<'tcx, T>(
             let &(inner_most_trait_ref, _, _) = stack.last().unwrap();
 
             let mut direct_super_traits_iter = tcx
-                .explicit_super_predicates_of(inner_most_trait_ref.def_id())
+                .explicit_super_predicates_of(inner_most_trait_ref.def_id)
                 .iter_identity_copied()
                 .filter_map(move |(pred, _)| {
-                    pred.instantiate_supertrait(tcx, inner_most_trait_ref).as_trait_clause()
+                    pred.instantiate_supertrait(tcx, ty::Binder::dummy(inner_most_trait_ref))
+                        .as_trait_clause()
+                })
+                .map(move |pred| {
+                    tcx.normalize_erasing_late_bound_regions(
+                        ty::TypingEnv::fully_monomorphized(),
+                        pred,
+                    )
+                    .trait_ref
                 });
 
             // Find an unvisited supertrait
@@ -136,16 +140,11 @@ fn prepare_vtable_segments_inner<'tcx, T>(
                 .find(|&super_trait| visited.insert(super_trait.upcast(tcx)))
             {
                 // Push it to the stack for the next iteration of 'diving_in to pick up
-                Some(unvisited_super_trait) => {
-                    // We're throwing away potential constness of super traits here.
-                    // FIXME: handle ~const super traits
-                    let next_super_trait = unvisited_super_trait.map_bound(|t| t.trait_ref);
-                    stack.push((
-                        next_super_trait,
-                        emit_vptr_on_new_entry,
-                        maybe_iter(Some(direct_super_traits_iter)),
-                    ))
-                }
+                Some(next_super_trait) => stack.push((
+                    next_super_trait,
+                    emit_vptr_on_new_entry,
+                    maybe_iter(Some(direct_super_traits_iter)),
+                )),
 
                 // There are no more unvisited direct super traits, dive-in finished
                 None => break 'diving_in,
@@ -154,8 +153,7 @@ fn prepare_vtable_segments_inner<'tcx, T>(
 
         // emit innermost item, move to next sibling and stop there if possible, otherwise jump to outer level.
         while let Some((inner_most_trait_ref, emit_vptr, mut siblings)) = stack.pop() {
-            let has_entries =
-                has_own_existential_vtable_entries(tcx, inner_most_trait_ref.def_id());
+            let has_entries = has_own_existential_vtable_entries(tcx, inner_most_trait_ref.def_id);
 
             segment_visitor(VtblSegment::TraitOwnEntries {
                 trait_ref: inner_most_trait_ref,
@@ -169,11 +167,6 @@ fn prepare_vtable_segments_inner<'tcx, T>(
             if let Some(next_inner_most_trait_ref) =
                 siblings.find(|&sibling| visited.insert(sibling.upcast(tcx)))
             {
-                // We're throwing away potential constness of super traits here.
-                // FIXME: handle ~const super traits
-                let next_inner_most_trait_ref =
-                    next_inner_most_trait_ref.map_bound(|t| t.trait_ref);
-
                 stack.push((next_inner_most_trait_ref, emit_vptr_on_new_entry, siblings));
 
                 // just pushed a new trait onto the stack, so we need to go through its super traits
@@ -192,15 +185,6 @@ fn maybe_iter<I: Iterator>(i: Option<I>) -> impl Iterator<Item = I::Item> {
     i.into_iter().flatten()
 }
 
-fn dump_vtable_entries<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    sp: Span,
-    trait_ref: ty::PolyTraitRef<'tcx>,
-    entries: &[VtblEntry<'tcx>],
-) {
-    tcx.dcx().emit_err(DumpVTableEntries { span: sp, trait_ref, entries: format!("{entries:#?}") });
-}
-
 fn has_own_existential_vtable_entries(tcx: TyCtxt<'_>, trait_def_id: DefId) -> bool {
     own_existential_vtable_entries_iter(tcx, trait_def_id).next().is_some()
 }
@@ -239,8 +223,15 @@ fn own_existential_vtable_entries_iter(
 /// that come from `trait_ref`, including its supertraits.
 fn vtable_entries<'tcx>(
     tcx: TyCtxt<'tcx>,
-    trait_ref: ty::PolyTraitRef<'tcx>,
+    trait_ref: ty::TraitRef<'tcx>,
 ) -> &'tcx [VtblEntry<'tcx>] {
+    debug_assert!(!trait_ref.has_non_region_infer() && !trait_ref.has_non_region_param());
+    debug_assert_eq!(
+        tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), trait_ref),
+        trait_ref,
+        "vtable trait ref should be normalized"
+    );
+
     debug!("vtable_entries({:?})", trait_ref);
 
     let mut entries = vec![];
@@ -251,33 +242,26 @@ fn vtable_entries<'tcx>(
                 entries.extend(TyCtxt::COMMON_VTABLE_ENTRIES);
             }
             VtblSegment::TraitOwnEntries { trait_ref, emit_vptr } => {
-                let existential_trait_ref = trait_ref
-                    .map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+                let existential_trait_ref = ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref);
 
                 // Lookup the shape of vtable for the trait.
                 let own_existential_entries =
-                    tcx.own_existential_vtable_entries(existential_trait_ref.def_id());
+                    tcx.own_existential_vtable_entries(existential_trait_ref.def_id);
 
                 let own_entries = own_existential_entries.iter().copied().map(|def_id| {
                     debug!("vtable_entries: trait_method={:?}", def_id);
 
                     // The method may have some early-bound lifetimes; add regions for those.
-                    let args = trait_ref.map_bound(|trait_ref| {
+                    // FIXME: Is this normalize needed?
+                    let args = tcx.normalize_erasing_regions(
+                        ty::TypingEnv::fully_monomorphized(),
                         GenericArgs::for_item(tcx, def_id, |param, _| match param.kind {
                             GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
                             GenericParamDefKind::Type { .. }
                             | GenericParamDefKind::Const { .. } => {
                                 trait_ref.args[param.index as usize]
                             }
-                        })
-                    });
-
-                    // The trait type may have higher-ranked lifetimes in it;
-                    // erase them if they appear, so that we get the type
-                    // at some particular call site.
-                    let args = tcx.normalize_erasing_late_bound_regions(
-                        ty::TypingEnv::fully_monomorphized(),
-                        args,
+                        }),
                     );
 
                     // It's possible that the method relies on where-clauses that
@@ -317,11 +301,6 @@ fn vtable_entries<'tcx>(
 
     let _ = prepare_vtable_segments(tcx, trait_ref, vtable_segment_callback);
 
-    if tcx.has_attr(trait_ref.def_id(), sym::rustc_dump_vtable) {
-        let sp = tcx.def_span(trait_ref.def_id());
-        dump_vtable_entries(tcx, sp, trait_ref, &entries);
-    }
-
     tcx.arena.alloc_from_iter(entries)
 }
 
@@ -329,14 +308,20 @@ fn vtable_entries<'tcx>(
 // for `Supertrait`'s methods in the vtable of `Subtrait`.
 pub(crate) fn first_method_vtable_slot<'tcx>(tcx: TyCtxt<'tcx>, key: ty::TraitRef<'tcx>) -> usize {
     debug_assert!(!key.has_non_region_infer() && !key.has_non_region_param());
+    debug_assert_eq!(
+        tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), key),
+        key,
+        "vtable trait ref should be normalized"
+    );
 
     let ty::Dynamic(source, _, _) = *key.self_ty().kind() else {
         bug!();
     };
-    let source_principal =
-        source.principal().unwrap().with_self_ty(tcx, tcx.types.trait_object_dummy_self);
+    let source_principal = tcx.instantiate_bound_regions_with_erased(
+        source.principal().unwrap().with_self_ty(tcx, tcx.types.trait_object_dummy_self),
+    );
 
-    let target_principal = ty::Binder::dummy(ty::ExistentialTraitRef::erase_self_ty(tcx, key));
+    let target_principal = ty::ExistentialTraitRef::erase_self_ty(tcx, key);
 
     let vtable_segment_callback = {
         let mut vptr_offset = 0;
@@ -346,17 +331,14 @@ pub(crate) fn first_method_vtable_slot<'tcx>(tcx: TyCtxt<'tcx>, key: ty::TraitRe
                     vptr_offset += TyCtxt::COMMON_VTABLE_ENTRIES.len();
                 }
                 VtblSegment::TraitOwnEntries { trait_ref: vtable_principal, emit_vptr } => {
-                    if trait_refs_are_compatible(
-                        tcx,
-                        vtable_principal
-                            .map_bound(|t| ty::ExistentialTraitRef::erase_self_ty(tcx, t)),
-                        target_principal,
-                    ) {
+                    if ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal)
+                        == target_principal
+                    {
                         return ControlFlow::Break(vptr_offset);
                     }
 
                     vptr_offset +=
-                        tcx.own_existential_vtable_entries(vtable_principal.def_id()).len();
+                        tcx.own_existential_vtable_entries(vtable_principal.def_id).len();
 
                     if emit_vptr {
                         vptr_offset += 1;
@@ -382,20 +364,27 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
     ),
 ) -> Option<usize> {
     debug_assert!(!key.has_non_region_infer() && !key.has_non_region_param());
+    debug_assert_eq!(
+        tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), key),
+        key,
+        "upcasting trait refs should be normalized"
+    );
+
     let (source, target) = key;
 
     // If the target principal is `None`, we can just return `None`.
     let ty::Dynamic(target, _, _) = *target.kind() else {
         bug!();
     };
-    let target_principal = target.principal()?;
+    let target_principal = tcx.instantiate_bound_regions_with_erased(target.principal()?);
 
     // Given that we have a target principal, it is a bug for there not to be a source principal.
     let ty::Dynamic(source, _, _) = *source.kind() else {
         bug!();
     };
-    let source_principal =
-        source.principal().unwrap().with_self_ty(tcx, tcx.types.trait_object_dummy_self);
+    let source_principal = tcx.instantiate_bound_regions_with_erased(
+        source.principal().unwrap().with_self_ty(tcx, tcx.types.trait_object_dummy_self),
+    );
 
     let vtable_segment_callback = {
         let mut vptr_offset = 0;
@@ -406,13 +395,10 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
                 }
                 VtblSegment::TraitOwnEntries { trait_ref: vtable_principal, emit_vptr } => {
                     vptr_offset +=
-                        tcx.own_existential_vtable_entries(vtable_principal.def_id()).len();
-                    if trait_refs_are_compatible(
-                        tcx,
-                        vtable_principal
-                            .map_bound(|t| ty::ExistentialTraitRef::erase_self_ty(tcx, t)),
-                        target_principal,
-                    ) {
+                        tcx.own_existential_vtable_entries(vtable_principal.def_id).len();
+                    if ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal)
+                        == target_principal
+                    {
                         if emit_vptr {
                             return ControlFlow::Break(Some(vptr_offset));
                         } else {
@@ -432,41 +418,6 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
     prepare_vtable_segments(tcx, source_principal, vtable_segment_callback).unwrap()
 }
 
-fn trait_refs_are_compatible<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    hr_vtable_principal: ty::PolyExistentialTraitRef<'tcx>,
-    hr_target_principal: ty::PolyExistentialTraitRef<'tcx>,
-) -> bool {
-    if hr_vtable_principal.def_id() != hr_target_principal.def_id() {
-        return false;
-    }
-
-    let (infcx, param_env) =
-        tcx.infer_ctxt().build_with_typing_env(ty::TypingEnv::fully_monomorphized());
-    let ocx = ObligationCtxt::new(&infcx);
-    let hr_source_principal =
-        ocx.normalize(&ObligationCause::dummy(), param_env, hr_vtable_principal);
-    let hr_target_principal =
-        ocx.normalize(&ObligationCause::dummy(), param_env, hr_target_principal);
-    infcx.enter_forall(hr_target_principal, |target_principal| {
-        let source_principal = infcx.instantiate_binder_with_fresh_vars(
-            DUMMY_SP,
-            BoundRegionConversionTime::HigherRankedType,
-            hr_source_principal,
-        );
-        let Ok(()) = ocx.eq_trace(
-            &ObligationCause::dummy(),
-            param_env,
-            ToTrace::to_trace(&ObligationCause::dummy(), hr_target_principal, hr_source_principal),
-            target_principal,
-            source_principal,
-        ) else {
-            return false;
-        };
-        ocx.select_all_or_error().is_empty()
-    })
-}
-
 pub(super) fn provide(providers: &mut Providers) {
     *providers = Providers {
         own_existential_vtable_entries,
diff --git a/src/doc/rustc-dev-guide/src/compiler-debugging.md b/src/doc/rustc-dev-guide/src/compiler-debugging.md
index a2a6c8085df..e2097b26e5c 100644
--- a/src/doc/rustc-dev-guide/src/compiler-debugging.md
+++ b/src/doc/rustc-dev-guide/src/compiler-debugging.md
@@ -275,7 +275,7 @@ Here are some notable ones:
 | `rustc_dump_def_parents` | Dumps the chain of `DefId` parents of certain definitions. |
 | `rustc_dump_item_bounds` | Dumps the [`item_bounds`] of an item. |
 | `rustc_dump_predicates` | Dumps the [`predicates_of`] an item. |
-| `rustc_dump_vtable` |  |
+| `rustc_dump_vtable` | Dumps the vtable layout of an impl, or a type alias of a dyn type. |
 | `rustc_hidden_type_of_opaques` | Dumps the [hidden type of each opaque types][opaq] in the crate. |
 | `rustc_layout` | [See this section](#debugging-type-layouts). |
 | `rustc_object_lifetime_default` | Dumps the [object lifetime defaults] of an item. |
diff --git a/src/tools/miri/tests/pass/dyn-upcast.rs b/src/tools/miri/tests/pass/dyn-upcast.rs
index 61410f7c4e0..f100c4d6a86 100644
--- a/src/tools/miri/tests/pass/dyn-upcast.rs
+++ b/src/tools/miri/tests/pass/dyn-upcast.rs
@@ -10,6 +10,8 @@ fn main() {
     replace_vptr();
     vtable_nop_cast();
     drop_principal();
+    modulo_binder();
+    modulo_assoc();
 }
 
 fn vtable_nop_cast() {
@@ -482,3 +484,53 @@ fn drop_principal() {
     println!("before");
     drop(y);
 }
+
+// Test for <https://github.com/rust-lang/rust/issues/135316>.
+fn modulo_binder() {
+    trait Supertrait<T> {
+        fn _print_numbers(&self, mem: &[usize; 100]) {
+            println!("{mem:?}");
+        }
+    }
+    impl<T> Supertrait<T> for () {}
+
+    trait Trait<T, U>: Supertrait<T> + Supertrait<U> {
+        fn say_hello(&self, _: &usize) {
+            println!("Hello!");
+        }
+    }
+    impl<T, U> Trait<T, U> for () {}
+
+    (&() as &'static dyn for<'a> Trait<&'static (), &'a ()>
+        as &'static dyn Trait<&'static (), &'static ()>)
+        .say_hello(&0);
+}
+
+// Test for <https://github.com/rust-lang/rust/issues/135315>.
+fn modulo_assoc() {
+    trait Supertrait<T> {
+        fn _print_numbers(&self, mem: &[usize; 100]) {
+            println!("{mem:?}");
+        }
+    }
+    impl<T> Supertrait<T> for () {}
+
+    trait Identity {
+        type Selff;
+    }
+    impl<Selff> Identity for Selff {
+        type Selff = Selff;
+    }
+
+    trait Middle<T>: Supertrait<()> + Supertrait<T> {
+        fn say_hello(&self, _: &usize) {
+            println!("Hello!");
+        }
+    }
+    impl<T> Middle<T> for () {}
+
+    trait Trait: Middle<<() as Identity>::Selff> {}
+    impl Trait for () {}
+
+    (&() as &dyn Trait as &dyn Middle<()>).say_hello(&0);
+}
diff --git a/src/tools/miri/tests/pass/dyn-upcast.stdout b/src/tools/miri/tests/pass/dyn-upcast.stdout
index edd99a114a1..379600db3d9 100644
--- a/src/tools/miri/tests/pass/dyn-upcast.stdout
+++ b/src/tools/miri/tests/pass/dyn-upcast.stdout
@@ -2,3 +2,5 @@ before
 goodbye
 before
 goodbye
+Hello!
+Hello!
diff --git a/tests/ui/traits/object/print_vtable_sizes.rs b/tests/ui/traits/object/print_vtable_sizes.rs
deleted file mode 100644
index 2b1745da5f3..00000000000
--- a/tests/ui/traits/object/print_vtable_sizes.rs
+++ /dev/null
@@ -1,62 +0,0 @@
-//@ check-pass
-//@ compile-flags: -Z print-vtable-sizes
-#![crate_type = "lib"]
-
-trait A<T: help::V>: AsRef<[T::V]> + AsMut<[T::V]> {}
-
-trait B<T>: AsRef<T> + AsRef<T> + AsRef<T> + AsRef<T> {}
-
-trait C {
-    fn x() {} // not dyn-compatible, shouldn't be reported
-}
-
-// This does not have any upcasting cost,
-// because both `Send` and `Sync` are traits
-// with no methods
-trait D: Send + Sync + help::MarkerWithSuper {}
-
-// This can't have no cost without reordering,
-// because `Super::f`.
-trait E: help::MarkerWithSuper + Send + Sync {}
-
-trait F {
-    fn a(&self);
-    fn b(&self);
-    fn c(&self);
-
-    fn d() -> Self
-    where
-        Self: Sized;
-}
-
-trait G: AsRef<u8> + AsRef<u16> + help::MarkerWithSuper {
-    fn a(&self);
-    fn b(&self);
-    fn c(&self);
-    fn d(&self);
-    fn e(&self);
-
-    fn f() -> Self
-    where
-        Self: Sized;
-}
-
-// Traits with the same name
-const _: () = {
-    trait S {}
-};
-const _: () = {
-    trait S {}
-};
-
-mod help {
-    pub trait V {
-        type V;
-    }
-
-    pub trait MarkerWithSuper: Super {}
-
-    pub trait Super {
-        fn f(&self);
-    }
-}
diff --git a/tests/ui/traits/object/print_vtable_sizes.stdout b/tests/ui/traits/object/print_vtable_sizes.stdout
deleted file mode 100644
index 4daf4769576..00000000000
--- a/tests/ui/traits/object/print_vtable_sizes.stdout
+++ /dev/null
@@ -1,11 +0,0 @@
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "A", "entries": "6", "entries_ignoring_upcasting": "5", "entries_for_upcasting": "1", "upcasting_cost_percent": "20" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "G", "entries": "13", "entries_ignoring_upcasting": "11", "entries_for_upcasting": "2", "upcasting_cost_percent": "18.181818181818183" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "B", "entries": "4", "entries_ignoring_upcasting": "4", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "D", "entries": "4", "entries_ignoring_upcasting": "4", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "E", "entries": "4", "entries_ignoring_upcasting": "4", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "F", "entries": "6", "entries_ignoring_upcasting": "6", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "_::S", "entries": "3", "entries_ignoring_upcasting": "3", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "_::S", "entries": "3", "entries_ignoring_upcasting": "3", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "help::MarkerWithSuper", "entries": "4", "entries_ignoring_upcasting": "4", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "help::Super", "entries": "4", "entries_ignoring_upcasting": "4", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
-print-vtable-sizes { "crate_name": "print_vtable_sizes", "trait_name": "help::V", "entries": "3", "entries_ignoring_upcasting": "3", "entries_for_upcasting": "0", "upcasting_cost_percent": "0" }
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.rs b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.rs
new file mode 100644
index 00000000000..796ddec46ac
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.rs
@@ -0,0 +1,27 @@
+#![feature(rustc_attrs)]
+
+// Test for <https://github.com/rust-lang/rust/issues/135316>.
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Trait<T, U>: Supertrait<T> + Supertrait<U> {
+    fn say_hello(&self, _: &usize) {
+    }
+}
+impl<T, U> Trait<T, U> for () {}
+
+// We should observe compatibility between these two vtables.
+
+#[rustc_dump_vtable]
+type First = dyn for<'a> Trait<&'static (), &'a ()>;
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
+type Second = dyn Trait<&'static (), &'static ()>;
+//~^ ERROR vtable entries
+
+fn main() {}
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.stderr b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.stderr
new file mode 100644
index 00000000000..24fa1650ca1
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.stderr
@@ -0,0 +1,26 @@
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn for<'a> Trait<&(), &'a ()> as Supertrait<&()>>::_print_numbers - shim(reify)),
+           Method(<dyn for<'a> Trait<&(), &'a ()> as Trait<&(), &()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-binder-vtable.rs:20:1
+   |
+LL | type First = dyn for<'a> Trait<&'static (), &'a ()>;
+   | ^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn Trait<&(), &()> as Supertrait<&()>>::_print_numbers - shim(reify)),
+           Method(<dyn Trait<&(), &()> as Trait<&(), &()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-binder-vtable.rs:24:1
+   |
+LL | type Second = dyn Trait<&'static (), &'static ()>;
+   | ^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.rs b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.rs
new file mode 100644
index 00000000000..510a1471af2
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.rs
@@ -0,0 +1,26 @@
+//@ run-pass
+//@ check-run-results
+
+// Test for <https://github.com/rust-lang/rust/issues/135316>.
+
+#![feature(trait_upcasting)]
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+        println!("{mem:?}");
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Trait<T, U>: Supertrait<T> + Supertrait<U> {
+    fn say_hello(&self, _: &usize) {
+        println!("Hello!");
+    }
+}
+impl<T, U> Trait<T, U> for () {}
+
+fn main() {
+    (&() as &'static dyn for<'a> Trait<&'static (), &'a ()>
+        as &'static dyn Trait<&'static (), &'static ()>)
+        .say_hello(&0);
+}
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.run.stdout b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.run.stdout
new file mode 100644
index 00000000000..10ddd6d257e
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder.run.stdout
@@ -0,0 +1 @@
+Hello!
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.rs b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.rs
new file mode 100644
index 00000000000..69a71859a5c
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.rs
@@ -0,0 +1,37 @@
+#![feature(rustc_attrs)]
+#![feature(trait_upcasting)]
+
+// Test for <https://github.com/rust-lang/rust/issues/135315>.
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+        println!("{mem:?}");
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Identity {
+    type Selff;
+}
+impl<Selff> Identity for Selff {
+    type Selff = Selff;
+}
+
+trait Middle<T>: Supertrait<()> + Supertrait<T> {
+    fn say_hello(&self, _: &usize) {
+        println!("Hello!");
+    }
+}
+impl<T> Middle<T> for () {}
+
+trait Trait: Middle<<() as Identity>::Selff> {}
+
+#[rustc_dump_vtable]
+impl Trait for () {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
+type Virtual = dyn Middle<()>;
+//~^ ERROR vtable entries
+
+fn main() {}
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.stderr b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.stderr
new file mode 100644
index 00000000000..757e2dc6939
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.stderr
@@ -0,0 +1,26 @@
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<() as Supertrait<()>>::_print_numbers),
+           Method(<() as Middle<()>>::say_hello),
+       ]
+  --> $DIR/multiple-supertraits-modulo-normalization-vtable.rs:30:1
+   |
+LL | impl Trait for () {}
+   | ^^^^^^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn Middle<()> as Supertrait<()>>::_print_numbers - shim(reify)),
+           Method(<dyn Middle<()> as Middle<()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-normalization-vtable.rs:34:1
+   |
+LL | type Virtual = dyn Middle<()>;
+   | ^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.rs b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.rs
new file mode 100644
index 00000000000..c744e6e64f5
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.rs
@@ -0,0 +1,34 @@
+//@ run-pass
+//@ check-run-results
+
+#![feature(trait_upcasting)]
+
+// Test for <https://github.com/rust-lang/rust/issues/135315>.
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+        println!("{mem:?}");
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Identity {
+    type Selff;
+}
+impl<Selff> Identity for Selff {
+    type Selff = Selff;
+}
+
+trait Middle<T>: Supertrait<()> + Supertrait<T> {
+    fn say_hello(&self, _: &usize) {
+        println!("Hello!");
+    }
+}
+impl<T> Middle<T> for () {}
+
+trait Trait: Middle<<() as Identity>::Selff> {}
+impl Trait for () {}
+
+fn main() {
+    (&() as &dyn Trait as &dyn Middle<()>).say_hello(&0);
+}
diff --git a/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.run.stdout b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.run.stdout
new file mode 100644
index 00000000000..10ddd6d257e
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization.run.stdout
@@ -0,0 +1 @@
+Hello!
diff --git a/tests/ui/traits/trait-upcasting/supertraits-modulo-inner-binder.rs b/tests/ui/traits/trait-upcasting/supertraits-modulo-inner-binder.rs
new file mode 100644
index 00000000000..6cd74b6c7f7
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/supertraits-modulo-inner-binder.rs
@@ -0,0 +1,30 @@
+//@ run-pass
+
+#![feature(trait_upcasting)]
+
+trait Super<U> {
+    fn call(&self)
+    where
+        U: HigherRanked,
+    {
+    }
+}
+
+impl<T> Super<T> for () {}
+
+trait HigherRanked {}
+impl HigherRanked for for<'a> fn(&'a ()) {}
+
+trait Unimplemented {}
+impl<T: Unimplemented> HigherRanked for T {}
+
+trait Sub: Super<fn(&'static ())> + Super<for<'a> fn(&'a ())> {}
+impl Sub for () {}
+
+fn main() {
+    let a: &dyn Sub = &();
+    // `Super<fn(&'static ())>` and `Super<for<'a> fn(&'a ())>` have different
+    // vtables and we need to upcast to the latter!
+    let b: &dyn Super<for<'a> fn(&'a ())> = a;
+    b.call();
+}
diff --git a/tests/ui/traits/vtable/multiple-markers.rs b/tests/ui/traits/vtable/multiple-markers.rs
index 8a9e7a006cf..8eba5135582 100644
--- a/tests/ui/traits/vtable/multiple-markers.rs
+++ b/tests/ui/traits/vtable/multiple-markers.rs
@@ -2,8 +2,7 @@
 //
 // This test makes sure that multiple marker (method-less) traits can reuse the
 // same pointer for upcasting.
-//
-//@ build-fail
+
 #![crate_type = "lib"]
 #![feature(rustc_attrs)]
 
@@ -17,17 +16,13 @@ trait T {
     fn method(&self) {}
 }
 
-#[rustc_dump_vtable]
-trait A: M0 + M1 + M2 + T {} //~ error: vtable entries for `<S as A>`:
+trait A: M0 + M1 + M2 + T {}
 
-#[rustc_dump_vtable]
-trait B: M0 + M1 + T + M2 {} //~ error: vtable entries for `<S as B>`:
+trait B: M0 + M1 + T + M2 {}
 
-#[rustc_dump_vtable]
-trait C: M0 + T + M1 + M2 {} //~ error: vtable entries for `<S as C>`:
+trait C: M0 + T + M1 + M2 {}
 
-#[rustc_dump_vtable]
-trait D: T + M0 + M1 + M2 {} //~ error: vtable entries for `<S as D>`:
+trait D: T + M0 + M1 + M2 {}
 
 struct S;
 
@@ -35,13 +30,21 @@ impl M0 for S {}
 impl M1 for S {}
 impl M2 for S {}
 impl T for S {}
+
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl C for S {}
-impl D for S {}
+//~^ ERROR vtable entries
 
-pub fn require_vtables() {
-    fn require_vtables(_: &dyn A, _: &dyn B, _: &dyn C, _: &dyn D) {}
+#[rustc_dump_vtable]
+impl D for S {}
+//~^ ERROR vtable entries
 
-    require_vtables(&S, &S, &S, &S)
-}
+fn main() {}
diff --git a/tests/ui/traits/vtable/multiple-markers.stderr b/tests/ui/traits/vtable/multiple-markers.stderr
index 36ac8b24eb5..35dd3c2516d 100644
--- a/tests/ui/traits/vtable/multiple-markers.stderr
+++ b/tests/ui/traits/vtable/multiple-markers.stderr
@@ -1,46 +1,46 @@
-error: vtable entries for `<S as A>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:21:1
+  --> $DIR/multiple-markers.rs:35:1
    |
-LL | trait A: M0 + M1 + M2 + T {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:24:1
+  --> $DIR/multiple-markers.rs:39:1
    |
-LL | trait B: M0 + M1 + T + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:27:1
+  --> $DIR/multiple-markers.rs:43:1
    |
-LL | trait C: M0 + T + M1 + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as D>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:30:1
+  --> $DIR/multiple-markers.rs:47:1
    |
-LL | trait D: T + M0 + M1 + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/traits/vtable/vtable-diamond.rs b/tests/ui/traits/vtable/vtable-diamond.rs
index 2cfa86c526d..56053f6d026 100644
--- a/tests/ui/traits/vtable/vtable-diamond.rs
+++ b/tests/ui/traits/vtable/vtable-diamond.rs
@@ -1,44 +1,37 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B: A {
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait D: B + C {
-    //~^ error vtable
     fn foo_d(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
-impl C for S {}
-impl D for S {}
+//~^ ERROR vtable entries
 
-fn foo(d: &dyn D) {
-    d.foo_d();
-}
+#[rustc_dump_vtable]
+impl C for S {}
+//~^ ERROR vtable entries
 
-fn bar(d: &dyn C) {
-    d.foo_c();
-}
+#[rustc_dump_vtable]
+impl D for S {}
+//~^ ERROR vtable entries
 
-fn main() {
-    foo(&S);
-    bar(&S);
-}
+fn main() {}
diff --git a/tests/ui/traits/vtable/vtable-diamond.stderr b/tests/ui/traits/vtable/vtable-diamond.stderr
index f3718c5d852..4644bf339b1 100644
--- a/tests/ui/traits/vtable/vtable-diamond.stderr
+++ b/tests/ui/traits/vtable/vtable-diamond.stderr
@@ -1,29 +1,52 @@
-error: vtable entries for `<S as D>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+       ]
+  --> $DIR/vtable-diamond.rs:22:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as A>::foo_a),
            Method(<S as B>::foo_b),
+       ]
+  --> $DIR/vtable-diamond.rs:26:1
+   |
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
            Method(<S as C>::foo_c),
-           TraitVPtr(<S as C>),
-           Method(<S as D>::foo_d),
        ]
-  --> $DIR/vtable-diamond.rs:21:1
+  --> $DIR/vtable-diamond.rs:30:1
    |
-LL | trait D: B + C {
-   | ^^^^^^^^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
            Method(<S as C>::foo_c),
+           TraitVPtr(<S as C>),
+           Method(<S as D>::foo_d),
        ]
-  --> $DIR/vtable-diamond.rs:15:1
+  --> $DIR/vtable-diamond.rs:34:1
    |
-LL | trait C: A {
-   | ^^^^^^^^^^
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
diff --git a/tests/ui/traits/vtable/vtable-dyn-incompatible.rs b/tests/ui/traits/vtable/vtable-dyn-incompatible.rs
index 64a8138bdcf..fb19dec4ace 100644
--- a/tests/ui/traits/vtable/vtable-dyn-incompatible.rs
+++ b/tests/ui/traits/vtable/vtable-dyn-incompatible.rs
@@ -1,15 +1,16 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
 // Ensure that dyn-incompatible methods in Iterator does not generate
 // vtable entries.
 
-#[rustc_dump_vtable]
 trait A: Iterator {}
-//~^ error vtable
 
 impl<T> A for T where T: Iterator {}
 
+#[rustc_dump_vtable]
+type Test = dyn A<Item=u8>;
+//~^ error vtable
+
 fn foo(_a: &mut dyn A<Item=u8>) {
 }
 
diff --git a/tests/ui/traits/vtable/vtable-dyn-incompatible.stderr b/tests/ui/traits/vtable/vtable-dyn-incompatible.stderr
index e442c3eac00..c80a763998b 100644
--- a/tests/ui/traits/vtable/vtable-dyn-incompatible.stderr
+++ b/tests/ui/traits/vtable/vtable-dyn-incompatible.stderr
@@ -1,16 +1,16 @@
-error: vtable entries for `<std::vec::IntoIter<u8> as A>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
-           Method(<std::vec::IntoIter<u8> as Iterator>::next),
-           Method(<std::vec::IntoIter<u8> as Iterator>::size_hint),
-           Method(<std::vec::IntoIter<u8> as Iterator>::advance_by),
-           Method(<std::vec::IntoIter<u8> as Iterator>::nth),
+           Method(<dyn A<Item = u8> as Iterator>::next - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::size_hint - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::advance_by - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::nth - shim(reify)),
        ]
-  --> $DIR/vtable-dyn-incompatible.rs:8:1
+  --> $DIR/vtable-dyn-incompatible.rs:11:1
    |
-LL | trait A: Iterator {}
-   | ^^^^^^^^^^^^^^^^^
+LL | type Test = dyn A<Item=u8>;
+   | ^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/traits/vtable/vtable-multi-level.rs b/tests/ui/traits/vtable/vtable-multi-level.rs
index bedbf84d303..67bac49f9f6 100644
--- a/tests/ui/traits/vtable/vtable-multi-level.rs
+++ b/tests/ui/traits/vtable/vtable-multi-level.rs
@@ -1,4 +1,3 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
 //   O --> G --> C --> A
@@ -10,134 +9,126 @@
 //           |-> M --> K
 //                 \-> L
 
-#[rustc_dump_vtable]
 trait A {
-    //~^ error vtable
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B {
-    //~^ error vtable
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A + B {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait D {
-    //~^ error vtable
     fn foo_d(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait E {
-    //~^ error vtable
     fn foo_e(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait F: D + E {
-    //~^ error vtable
     fn foo_f(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait G: C + F {
     fn foo_g(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait H {
-    //~^ error vtable
     fn foo_h(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait I {
-    //~^ error vtable
     fn foo_i(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait J: H + I {
-    //~^ error vtable
     fn foo_j(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait K {
-    //~^ error vtable
     fn foo_k(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait L {
-    //~^ error vtable
     fn foo_l(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait M: K + L {
-    //~^ error vtable
     fn foo_m(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait N: J + M {
-    //~^ error vtable
     fn foo_n(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait O: G + N {
-    //~^ error vtable
     fn foo_o(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl C for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl D for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl E for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl F for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl G for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl H for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl I for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl J for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl K for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl L for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl M for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl N for S {}
-impl O for S {}
+//~^ ERROR vtable entries
 
-macro_rules! monomorphize_vtable {
-    ($trait:ident) => {{
-        fn foo(_ : &dyn $trait) {}
-        foo(&S);
-    }}
-}
+#[rustc_dump_vtable]
+impl O for S {}
+//~^ ERROR vtable entries
 
-fn main() {
-    monomorphize_vtable!(O);
-
-    monomorphize_vtable!(A);
-    monomorphize_vtable!(B);
-    monomorphize_vtable!(C);
-    monomorphize_vtable!(D);
-    monomorphize_vtable!(E);
-    monomorphize_vtable!(F);
-    monomorphize_vtable!(H);
-    monomorphize_vtable!(I);
-    monomorphize_vtable!(J);
-    monomorphize_vtable!(K);
-    monomorphize_vtable!(L);
-    monomorphize_vtable!(M);
-    monomorphize_vtable!(N);
-}
+fn main() {}
diff --git a/tests/ui/traits/vtable/vtable-multi-level.stderr b/tests/ui/traits/vtable/vtable-multi-level.stderr
index c4389e23fc1..961900aa3d2 100644
--- a/tests/ui/traits/vtable/vtable-multi-level.stderr
+++ b/tests/ui/traits/vtable/vtable-multi-level.stderr
@@ -1,134 +1,119 @@
-error: vtable entries for `<S as O>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as A>::foo_a),
-           Method(<S as B>::foo_b),
-           TraitVPtr(<S as B>),
-           Method(<S as C>::foo_c),
-           Method(<S as D>::foo_d),
-           TraitVPtr(<S as D>),
-           Method(<S as E>::foo_e),
-           TraitVPtr(<S as E>),
-           Method(<S as F>::foo_f),
-           TraitVPtr(<S as F>),
-           Method(<S as G>::foo_g),
-           Method(<S as H>::foo_h),
-           TraitVPtr(<S as H>),
-           Method(<S as I>::foo_i),
-           TraitVPtr(<S as I>),
-           Method(<S as J>::foo_j),
-           TraitVPtr(<S as J>),
-           Method(<S as K>::foo_k),
-           TraitVPtr(<S as K>),
-           Method(<S as L>::foo_l),
-           TraitVPtr(<S as L>),
-           Method(<S as M>::foo_m),
-           TraitVPtr(<S as M>),
-           Method(<S as N>::foo_n),
-           TraitVPtr(<S as N>),
-           Method(<S as O>::foo_o),
        ]
-  --> $DIR/vtable-multi-level.rs:97:1
+  --> $DIR/vtable-multi-level.rs:75:1
    |
-LL | trait O: G + N {
-   | ^^^^^^^^^^^^^^
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as A>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
-           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
        ]
-  --> $DIR/vtable-multi-level.rs:14:1
+  --> $DIR/vtable-multi-level.rs:79:1
    |
-LL | trait A {
-   | ^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
+           Method(<S as A>::foo_a),
            Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
        ]
-  --> $DIR/vtable-multi-level.rs:20:1
+  --> $DIR/vtable-multi-level.rs:83:1
    |
-LL | trait B {
-   | ^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
-           Method(<S as A>::foo_a),
-           Method(<S as B>::foo_b),
-           TraitVPtr(<S as B>),
-           Method(<S as C>::foo_c),
+           Method(<S as D>::foo_d),
        ]
-  --> $DIR/vtable-multi-level.rs:26:1
+  --> $DIR/vtable-multi-level.rs:87:1
    |
-LL | trait C: A + B {
-   | ^^^^^^^^^^^^^^
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as D>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
-           Method(<S as D>::foo_d),
+           Method(<S as E>::foo_e),
        ]
-  --> $DIR/vtable-multi-level.rs:32:1
+  --> $DIR/vtable-multi-level.rs:91:1
    |
-LL | trait D {
-   | ^^^^^^^
+LL | impl E for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as E>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
+           Method(<S as D>::foo_d),
            Method(<S as E>::foo_e),
+           TraitVPtr(<S as E>),
+           Method(<S as F>::foo_f),
        ]
-  --> $DIR/vtable-multi-level.rs:38:1
+  --> $DIR/vtable-multi-level.rs:95:1
    |
-LL | trait E {
-   | ^^^^^^^
+LL | impl F for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as F>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
            Method(<S as D>::foo_d),
+           TraitVPtr(<S as D>),
            Method(<S as E>::foo_e),
            TraitVPtr(<S as E>),
            Method(<S as F>::foo_f),
+           TraitVPtr(<S as F>),
+           Method(<S as G>::foo_g),
        ]
-  --> $DIR/vtable-multi-level.rs:44:1
+  --> $DIR/vtable-multi-level.rs:99:1
    |
-LL | trait F: D + E {
-   | ^^^^^^^^^^^^^^
+LL | impl G for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as H>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as H>::foo_h),
        ]
-  --> $DIR/vtable-multi-level.rs:55:1
+  --> $DIR/vtable-multi-level.rs:103:1
    |
-LL | trait H {
-   | ^^^^^^^
+LL | impl H for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as I>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as I>::foo_i),
        ]
-  --> $DIR/vtable-multi-level.rs:61:1
+  --> $DIR/vtable-multi-level.rs:107:1
    |
-LL | trait I {
-   | ^^^^^^^
+LL | impl I for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as J>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -137,34 +122,34 @@ error: vtable entries for `<S as J>`: [
            TraitVPtr(<S as I>),
            Method(<S as J>::foo_j),
        ]
-  --> $DIR/vtable-multi-level.rs:67:1
+  --> $DIR/vtable-multi-level.rs:111:1
    |
-LL | trait J: H + I {
-   | ^^^^^^^^^^^^^^
+LL | impl J for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as K>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as K>::foo_k),
        ]
-  --> $DIR/vtable-multi-level.rs:73:1
+  --> $DIR/vtable-multi-level.rs:115:1
    |
-LL | trait K {
-   | ^^^^^^^
+LL | impl K for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as L>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as L>::foo_l),
        ]
-  --> $DIR/vtable-multi-level.rs:79:1
+  --> $DIR/vtable-multi-level.rs:119:1
    |
-LL | trait L {
-   | ^^^^^^^
+LL | impl L for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as M>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -173,12 +158,12 @@ error: vtable entries for `<S as M>`: [
            TraitVPtr(<S as L>),
            Method(<S as M>::foo_m),
        ]
-  --> $DIR/vtable-multi-level.rs:85:1
+  --> $DIR/vtable-multi-level.rs:123:1
    |
-LL | trait M: K + L {
-   | ^^^^^^^^^^^^^^
+LL | impl M for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as N>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -194,10 +179,46 @@ error: vtable entries for `<S as N>`: [
            TraitVPtr(<S as M>),
            Method(<S as N>::foo_n),
        ]
-  --> $DIR/vtable-multi-level.rs:91:1
+  --> $DIR/vtable-multi-level.rs:127:1
+   |
+LL | impl N for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
+           Method(<S as D>::foo_d),
+           TraitVPtr(<S as D>),
+           Method(<S as E>::foo_e),
+           TraitVPtr(<S as E>),
+           Method(<S as F>::foo_f),
+           TraitVPtr(<S as F>),
+           Method(<S as G>::foo_g),
+           Method(<S as H>::foo_h),
+           TraitVPtr(<S as H>),
+           Method(<S as I>::foo_i),
+           TraitVPtr(<S as I>),
+           Method(<S as J>::foo_j),
+           TraitVPtr(<S as J>),
+           Method(<S as K>::foo_k),
+           TraitVPtr(<S as K>),
+           Method(<S as L>::foo_l),
+           TraitVPtr(<S as L>),
+           Method(<S as M>::foo_m),
+           TraitVPtr(<S as M>),
+           Method(<S as N>::foo_n),
+           TraitVPtr(<S as N>),
+           Method(<S as O>::foo_o),
+       ]
+  --> $DIR/vtable-multi-level.rs:131:1
    |
-LL | trait N: J + M {
-   | ^^^^^^^^^^^^^^
+LL | impl O for S {}
+   | ^^^^^^^^^^^^
 
-error: aborting due to 14 previous errors
+error: aborting due to 15 previous errors
 
diff --git a/tests/ui/traits/vtable/vtable-multiple.rs b/tests/ui/traits/vtable/vtable-multiple.rs
index beaaf4db6b1..51e20ee20c9 100644
--- a/tests/ui/traits/vtable/vtable-multiple.rs
+++ b/tests/ui/traits/vtable/vtable-multiple.rs
@@ -1,33 +1,29 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B {
-    //~^ error vtable
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A + B {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ error vtable
+
+#[rustc_dump_vtable]
 impl B for S {}
-impl C for S {}
+//~^ error vtable
 
-fn foo(c: &dyn C) {}
-fn bar(c: &dyn B) {}
+#[rustc_dump_vtable]
+impl C for S {}
+//~^ error vtable
 
-fn main() {
-    foo(&S);
-    bar(&S);
-}
+fn main() {}
diff --git a/tests/ui/traits/vtable/vtable-multiple.stderr b/tests/ui/traits/vtable/vtable-multiple.stderr
index 0dcd8443309..bae44148baa 100644
--- a/tests/ui/traits/vtable/vtable-multiple.stderr
+++ b/tests/ui/traits/vtable/vtable-multiple.stderr
@@ -1,27 +1,38 @@
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as A>::foo_a),
+       ]
+  --> $DIR/vtable-multiple.rs:18:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
            Method(<S as B>::foo_b),
-           TraitVPtr(<S as B>),
-           Method(<S as C>::foo_c),
        ]
-  --> $DIR/vtable-multiple.rs:16:1
+  --> $DIR/vtable-multiple.rs:22:1
    |
-LL | trait C: A + B {
-   | ^^^^^^^^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
+           Method(<S as A>::foo_a),
            Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
        ]
-  --> $DIR/vtable-multiple.rs:10:1
+  --> $DIR/vtable-multiple.rs:26:1
    |
-LL | trait B {
-   | ^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
diff --git a/tests/ui/traits/vtable/vtable-vacant.rs b/tests/ui/traits/vtable/vtable-vacant.rs
index b3c76815703..b023565c56e 100644
--- a/tests/ui/traits/vtable/vtable-vacant.rs
+++ b/tests/ui/traits/vtable/vtable-vacant.rs
@@ -1,18 +1,14 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 #![feature(negative_impls)]
 
 // B --> A
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a1(&self) {}
     fn foo_a2(&self) where Self: Send {}
 }
 
-#[rustc_dump_vtable]
 trait B: A {
-    //~^ error vtable
     fn foo_b1(&self) {}
     fn foo_b2(&self) where Self: Send {}
 }
@@ -20,11 +16,12 @@ trait B: A {
 struct S;
 impl !Send for S {}
 
+#[rustc_dump_vtable]
 impl A for S {}
-impl B for S {}
+//~^ error vtable
 
-fn foo(_: &dyn B) {}
+#[rustc_dump_vtable]
+impl B for S {}
+//~^ error vtable
 
-fn main() {
-    foo(&S);
-}
+fn main() {}
diff --git a/tests/ui/traits/vtable/vtable-vacant.stderr b/tests/ui/traits/vtable/vtable-vacant.stderr
index f6961ca010e..ed8466f7f2e 100644
--- a/tests/ui/traits/vtable/vtable-vacant.stderr
+++ b/tests/ui/traits/vtable/vtable-vacant.stderr
@@ -1,4 +1,16 @@
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a1),
+           Vacant,
+       ]
+  --> $DIR/vtable-vacant.rs:20:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -7,10 +19,10 @@ error: vtable entries for `<S as B>`: [
            Method(<S as B>::foo_b1),
            Vacant,
        ]
-  --> $DIR/vtable-vacant.rs:14:1
+  --> $DIR/vtable-vacant.rs:24:1
    |
-LL | trait B: A {
-   | ^^^^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors