about summary refs log tree commit diff
path: root/compiler
diff options
context:
space:
mode:
authorStuart Cook <Zalathar@users.noreply.github.com>2025-09-18 11:48:51 +1000
committerGitHub <noreply@github.com>2025-09-18 11:48:51 +1000
commit540fd20ba66358fec0322c347bcffb0d29c02deb (patch)
treeedaa3f9d51f7c403b96e0bdaf41ce06fec3ad199 /compiler
parent34a805b0f5860471efd5b3acbae02146d97b37f7 (diff)
parent34062b124f00eb7c35da2e3981cfb5b45dd26039 (diff)
downloadrust-540fd20ba66358fec0322c347bcffb0d29c02deb.tar.gz
rust-540fd20ba66358fec0322c347bcffb0d29c02deb.zip
Rollup merge of #146664 - fmease:clean-up-dyn, r=jdonszelmann
Clean up `ty::Dynamic`

1. As a follow-up to PR rust-lang/rust#143036, remove `DynKind` entirely.
2. Inside HIR ty lowering, consolidate modules `dyn_compatibility` and `lint` into `dyn_trait`
   * `dyn_compatibility` wasn't about dyn compatibility itself, it's about lowering trait object types
   * `lint` contained dyn-Trait-specific diagnostics+lints only
Diffstat (limited to 'compiler')
-rw-r--r--compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs4
-rw-r--r--compiler/rustc_borrowck/src/lib.rs4
-rw-r--r--compiler/rustc_borrowck/src/type_check/mod.rs6
-rw-r--r--compiler/rustc_codegen_cranelift/src/abi/mod.rs2
-rw-r--r--compiler/rustc_codegen_cranelift/src/unsize.rs4
-rw-r--r--compiler/rustc_codegen_cranelift/src/value_and_place.rs3
-rw-r--r--compiler/rustc_codegen_ssa/src/base.rs6
-rw-r--r--compiler/rustc_codegen_ssa/src/meth.rs2
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/block.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/call.rs6
-rw-r--r--compiler/rustc_const_eval/src/interpret/cast.rs4
-rw-r--r--compiler/rustc_const_eval/src/interpret/eval_context.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/intrinsics.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/stack.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/traits.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/validity.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/visitor.rs2
-rw-r--r--compiler/rustc_const_eval/src/util/type_name.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/collect/dump.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs (renamed from compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs)558
-rw-r--r--compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs533
-rw-r--r--compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs19
-rw-r--r--compiler/rustc_hir_analysis/src/variance/constraints.rs2
-rw-r--r--compiler/rustc_hir_typeck/src/cast.rs8
-rw-r--r--compiler/rustc_hir_typeck/src/coercion.rs2
-rw-r--r--compiler/rustc_hir_typeck/src/method/suggest.rs2
-rw-r--r--compiler/rustc_lint/src/deref_into_dyn_supertrait.rs4
-rw-r--r--compiler/rustc_lint/src/types.rs2
-rw-r--r--compiler/rustc_lint/src/unused.rs2
-rw-r--r--compiler/rustc_middle/src/ty/context.rs2
-rw-r--r--compiler/rustc_middle/src/ty/layout.rs6
-rw-r--r--compiler/rustc_middle/src/ty/print/pretty.rs6
-rw-r--r--compiler/rustc_middle/src/ty/significant_drop_order.rs2
-rw-r--r--compiler/rustc_middle/src/ty/structural_impls.rs14
-rw-r--r--compiler/rustc_middle/src/ty/sty.rs14
-rw-r--r--compiler/rustc_mir_dataflow/src/move_paths/builder.rs4
-rw-r--r--compiler/rustc_mir_transform/src/coroutine.rs2
-rw-r--r--compiler/rustc_next_trait_solver/src/canonicalizer.rs2
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs2
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs6
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs4
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/trait_goals.rs12
-rw-r--r--compiler/rustc_passes/src/check_export.rs2
-rw-r--r--compiler/rustc_pattern_analysis/src/rustc.rs2
-rw-r--r--compiler/rustc_public/src/ty.rs11
-rw-r--r--compiler/rustc_public/src/unstable/convert/internal.rs19
-rw-r--r--compiler/rustc_public/src/unstable/convert/stable/ty.rs27
-rw-r--r--compiler/rustc_public/src/visitor.rs2
-rw-r--r--compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs6
-rw-r--r--compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs8
-rw-r--r--compiler/rustc_symbol_mangling/src/export.rs2
-rw-r--r--compiler/rustc_symbol_mangling/src/v0.rs6
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs2
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs12
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/infer/region.rs2
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs2
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs2
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs6
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs8
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/confirmation.rs14
-rw-r--r--compiler/rustc_trait_selection/src/traits/vtable.rs6
-rw-r--r--compiler/rustc_trait_selection/src/traits/wf.rs2
-rw-r--r--compiler/rustc_ty_utils/src/layout.rs2
-rw-r--r--compiler/rustc_ty_utils/src/ty.rs4
-rw-r--r--compiler/rustc_type_ir/src/flags.rs2
-rw-r--r--compiler/rustc_type_ir/src/inherent.rs9
-rw-r--r--compiler/rustc_type_ir/src/lib.rs1
-rw-r--r--compiler/rustc_type_ir/src/outlives.rs2
-rw-r--r--compiler/rustc_type_ir/src/relate.rs15
-rw-r--r--compiler/rustc_type_ir/src/ty_kind.rs22
-rw-r--r--compiler/rustc_type_ir/src/walk.rs2
72 files changed, 687 insertions, 782 deletions
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index fda96dde826..7ca07bb9b43 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -438,7 +438,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
 
             let elaborated_args =
                 std::iter::zip(*args, &generics.own_params).map(|(arg, param)| {
-                    if let Some(ty::Dynamic(obj, _, ty::Dyn)) = arg.as_type().map(Ty::kind) {
+                    if let Some(ty::Dynamic(obj, _)) = arg.as_type().map(Ty::kind) {
                         let default = tcx.object_lifetime_default(param.def_id);
 
                         let re_static = tcx.lifetimes.re_static;
@@ -464,7 +464,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
 
                         has_dyn = true;
 
-                        Ty::new_dynamic(tcx, obj, implied_region, ty::Dyn).into()
+                        Ty::new_dynamic(tcx, obj, implied_region).into()
                     } else {
                         arg
                     }
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index f196bd04d0e..4c380ddcf70 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -1903,7 +1903,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                     | ty::Slice(_)
                     | ty::FnDef(_, _)
                     | ty::FnPtr(..)
-                    | ty::Dynamic(_, _, _)
+                    | ty::Dynamic(_, _)
                     | ty::Closure(_, _)
                     | ty::CoroutineClosure(_, _)
                     | ty::Coroutine(_, _)
@@ -1949,7 +1949,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                     | ty::Ref(_, _, _)
                     | ty::FnDef(_, _)
                     | ty::FnPtr(..)
-                    | ty::Dynamic(_, _, _)
+                    | ty::Dynamic(_, _)
                     | ty::CoroutineWitness(..)
                     | ty::Never
                     | ty::UnsafeBinder(_)
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index dcedf0b1532..19cbcd139aa 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -1487,9 +1487,9 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                                     unsize_to: None,
                                 },
                             );
-                        } else if let ty::Dynamic(src_tty, _src_lt, ty::Dyn) =
+                        } else if let ty::Dynamic(src_tty, _src_lt) =
                             *self.struct_tail(src.ty, location).kind()
-                            && let ty::Dynamic(dst_tty, dst_lt, ty::Dyn) =
+                            && let ty::Dynamic(dst_tty, dst_lt) =
                                 *self.struct_tail(dst.ty, location).kind()
                             && src_tty.principal().is_some()
                             && dst_tty.principal().is_some()
@@ -1511,7 +1511,6 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                                 // FIXME: Once we disallow casting `*const dyn Trait + 'short`
                                 // to `*const dyn Trait + 'long`, then this can just be `src_lt`.
                                 dst_lt,
-                                ty::Dyn,
                             );
                             let dst_obj = Ty::new_dynamic(
                                 tcx,
@@ -1519,7 +1518,6 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                                     &dst_tty.without_auto_traits().collect::<Vec<_>>(),
                                 ),
                                 dst_lt,
-                                ty::Dyn,
                             );
 
                             debug!(?src_tty, ?dst_tty, ?src_obj, ?dst_obj);
diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 7d0731c77bd..29ee46194de 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -715,7 +715,7 @@ pub(crate) fn codegen_drop<'tcx>(
         fx.bcx.ins().jump(ret_block, &[]);
     } else {
         match ty.kind() {
-            ty::Dynamic(_, _, ty::Dyn) => {
+            ty::Dynamic(_, _) => {
                 // IN THIS ARM, WE HAVE:
                 // ty = *mut (dyn Trait)
                 // which is: exists<T> ( *mut T,    Vtable<T: Trait> )
diff --git a/compiler/rustc_codegen_cranelift/src/unsize.rs b/compiler/rustc_codegen_cranelift/src/unsize.rs
index 2aee0b2e974..643c7feb89a 100644
--- a/compiler/rustc_codegen_cranelift/src/unsize.rs
+++ b/compiler/rustc_codegen_cranelift/src/unsize.rs
@@ -30,9 +30,7 @@ pub(crate) fn unsized_info<'tcx>(
             fx.pointer_type,
             len.try_to_target_usize(fx.tcx).expect("expected monomorphic const in codegen") as i64,
         ),
-        (&ty::Dynamic(data_a, _, src_dyn_kind), &ty::Dynamic(data_b, _, target_dyn_kind))
-            if src_dyn_kind == target_dyn_kind =>
-        {
+        (&ty::Dynamic(data_a, _), &ty::Dynamic(data_b, _)) => {
             let old_info =
                 old_info.expect("unsized_info: missing old info for trait upcasting coercion");
             let b_principal_def_id = data_b.principal_def_id();
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
index 9d73f200afe..4519fa1a270 100644
--- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs
+++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
@@ -909,8 +909,7 @@ pub(crate) fn assert_assignable<'tcx>(
             );
             // fn(&T) -> for<'l> fn(&'l T) is allowed
         }
-        (&ty::Dynamic(from_traits, _, _from_kind), &ty::Dynamic(to_traits, _, _to_kind)) => {
-            // FIXME(dyn-star): Do the right thing with DynKinds
+        (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
             for (from, to) in from_traits.iter().zip(to_traits) {
                 let from = fx.tcx.normalize_erasing_late_bound_regions(fx.typing_env(), from);
                 let to = fx.tcx.normalize_erasing_late_bound_regions(fx.typing_env(), to);
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 45b028aa8ef..68a2f43ec67 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -168,9 +168,7 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         (&ty::Array(_, len), &ty::Slice(_)) => cx.const_usize(
             len.try_to_target_usize(cx.tcx()).expect("expected monomorphic const in codegen"),
         ),
-        (&ty::Dynamic(data_a, _, src_dyn_kind), &ty::Dynamic(data_b, _, target_dyn_kind))
-            if src_dyn_kind == target_dyn_kind =>
-        {
+        (&ty::Dynamic(data_a, _), &ty::Dynamic(data_b, _)) => {
             let old_info =
                 old_info.expect("unsized_info: missing old info for trait upcasting coercion");
             let b_principal_def_id = data_b.principal_def_id();
@@ -208,7 +206,7 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 old_info
             }
         }
-        (_, ty::Dynamic(data, _, _)) => meth::get_vtable(
+        (_, ty::Dynamic(data, _)) => meth::get_vtable(
             cx,
             source,
             data.principal()
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index 34ad35a729b..2fa466b5001 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -78,7 +78,7 @@ fn dyn_trait_in_self<'tcx>(
 ) -> Option<ty::ExistentialTraitRef<'tcx>> {
     for arg in ty.peel_refs().walk() {
         if let GenericArgKind::Type(ty) = arg.kind()
-            && let ty::Dynamic(data, _, _) = ty.kind()
+            && let ty::Dynamic(data, _) = ty.kind()
         {
             // FIXME(arbitrary_self_types): This is likely broken for receivers which
             // have a "non-self" trait objects as a generic argument.
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 6492ef73956..1b218a0d339 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -614,7 +614,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let (maybe_null, drop_fn, fn_abi, drop_instance) = match ty.kind() {
             // FIXME(eddyb) perhaps move some of this logic into
             // `Instance::resolve_drop_in_place`?
-            ty::Dynamic(_, _, ty::Dyn) => {
+            ty::Dynamic(_, _) => {
                 // IN THIS ARM, WE HAVE:
                 // ty = *mut (dyn Trait)
                 // which is: exists<T> ( *mut T,    Vtable<T: Trait> )
diff --git a/compiler/rustc_const_eval/src/interpret/call.rs b/compiler/rustc_const_eval/src/interpret/call.rs
index 4cb88d44e1b..23e4a2921ea 100644
--- a/compiler/rustc_const_eval/src/interpret/call.rs
+++ b/compiler/rustc_const_eval/src/interpret/call.rs
@@ -658,7 +658,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                             let val = self.read_immediate(&receiver)?;
                             break self.ref_to_mplace(&val)?;
                         }
-                        ty::Dynamic(.., ty::Dyn) => break receiver.assert_mem_place(), // no immediate unsized values
+                        ty::Dynamic(..) => break receiver.assert_mem_place(), // no immediate unsized values
                         _ => {
                             // Not there yet, search for the only non-ZST field.
                             // (The rules for `DispatchFromDyn` ensure there's exactly one such field.)
@@ -675,7 +675,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 // (For that reason we also cannot use `unpack_dyn_trait`.)
                 let receiver_tail =
                     self.tcx.struct_tail_for_codegen(receiver_place.layout.ty, self.typing_env);
-                let ty::Dynamic(receiver_trait, _, ty::Dyn) = receiver_tail.kind() else {
+                let ty::Dynamic(receiver_trait, _) = receiver_tail.kind() else {
                     span_bug!(self.cur_span(), "dynamic call on non-`dyn` type {}", receiver_tail)
                 };
                 assert!(receiver_place.layout.is_unsized());
@@ -822,7 +822,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         // instead we do the virtual call stuff ourselves. It's easier here than in `eval_fn_call`
         // since we can just get a place of the underlying type and use `mplace_to_ref`.
         let place = match place.layout.ty.kind() {
-            ty::Dynamic(data, _, ty::Dyn) => {
+            ty::Dynamic(data, _) => {
                 // Dropping a trait object. Need to find actual drop fn.
                 self.unpack_dyn_trait(&place, data)?
             }
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index e3afeda5b7c..0075740e031 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -386,7 +386,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 );
                 self.write_immediate(val, dest)
             }
-            (ty::Dynamic(data_a, _, ty::Dyn), ty::Dynamic(data_b, _, ty::Dyn)) => {
+            (ty::Dynamic(data_a, _), ty::Dynamic(data_b, _)) => {
                 let val = self.read_immediate(src)?;
                 // MIR building generates odd NOP casts, prevent them from causing unexpected trouble.
                 // See <https://github.com/rust-lang/rust/issues/128880>.
@@ -436,7 +436,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let new_vptr = self.get_vtable_ptr(ty, data_b)?;
                 self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
             }
-            (_, &ty::Dynamic(data, _, ty::Dyn)) => {
+            (_, &ty::Dynamic(data, _)) => {
                 // Initial cast from sized to dyn trait
                 let vtable = self.get_vtable_ptr(src_pointee_ty, data)?;
                 let ptr = self.read_pointer(src)?;
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 91ed71ac3e5..0e4a98f0941 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -469,7 +469,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
                 interp_ok(Some((full_size, full_align)))
             }
-            ty::Dynamic(expected_trait, _, ty::Dyn) => {
+            ty::Dynamic(expected_trait, _) => {
                 let vtable = metadata.unwrap_meta().to_pointer(self)?;
                 // Read size and align from vtable (already checks size).
                 interp_ok(Some(self.get_vtable_size_and_align(vtable, Some(expected_trait))?))
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 5e3d0a15d8b..418dd658121 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -181,7 +181,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                     | ty::Ref(_, _, _)
                     | ty::FnDef(_, _)
                     | ty::FnPtr(..)
-                    | ty::Dynamic(_, _, _)
+                    | ty::Dynamic(_, _)
                     | ty::Closure(_, _)
                     | ty::CoroutineClosure(_, _)
                     | ty::Coroutine(_, _)
diff --git a/compiler/rustc_const_eval/src/interpret/stack.rs b/compiler/rustc_const_eval/src/interpret/stack.rs
index 7cabfd96121..1c1c59da9d8 100644
--- a/compiler/rustc_const_eval/src/interpret/stack.rs
+++ b/compiler/rustc_const_eval/src/interpret/stack.rs
@@ -509,7 +509,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 | ty::Never
                 | ty::Error(_) => true,
 
-                ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => false,
+                ty::Str | ty::Slice(_) | ty::Dynamic(_, _) | ty::Foreign(..) => false,
 
                 ty::Tuple(tys) => tys.last().is_none_or(|ty| is_very_trivially_sized(*ty)),
 
diff --git a/compiler/rustc_const_eval/src/interpret/traits.rs b/compiler/rustc_const_eval/src/interpret/traits.rs
index 870f9a396ae..d982ed96167 100644
--- a/compiler/rustc_const_eval/src/interpret/traits.rs
+++ b/compiler/rustc_const_eval/src/interpret/traits.rs
@@ -109,7 +109,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
         assert!(
-            matches!(mplace.layout.ty.kind(), ty::Dynamic(_, _, ty::Dyn)),
+            matches!(mplace.layout.ty.kind(), ty::Dynamic(_, _)),
             "`unpack_dyn_trait` only makes sense on `dyn*` types"
         );
         let vtable = mplace.meta().unwrap_meta().to_pointer(self)?;
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 02e3d90f4af..9adc3fa4631 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -449,7 +449,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
     ) -> InterpResult<'tcx> {
         let tail = self.ecx.tcx.struct_tail_for_codegen(pointee.ty, self.ecx.typing_env);
         match tail.kind() {
-            ty::Dynamic(data, _, ty::Dyn) => {
+            ty::Dynamic(data, _) => {
                 let vtable = meta.unwrap_meta().to_pointer(self.ecx)?;
                 // Make sure it is a genuine vtable pointer for the right trait.
                 try_validation!(
diff --git a/compiler/rustc_const_eval/src/interpret/visitor.rs b/compiler/rustc_const_eval/src/interpret/visitor.rs
index 82c50fac6c0..b5de10c7dcd 100644
--- a/compiler/rustc_const_eval/src/interpret/visitor.rs
+++ b/compiler/rustc_const_eval/src/interpret/visitor.rs
@@ -90,7 +90,7 @@ pub trait ValueVisitor<'tcx, M: Machine<'tcx>>: Sized {
         // Special treatment for special types, where the (static) layout is not sufficient.
         match *ty.kind() {
             // If it is a trait object, switch to the real type that was used to create it.
-            ty::Dynamic(data, _, ty::Dyn) => {
+            ty::Dynamic(data, _) => {
                 // Dyn types. This is unsized, and the actual dynamic type of the data is given by the
                 // vtable stored in the place metadata.
                 // unsized values are never immediate, so we can assert_mem_place
diff --git a/compiler/rustc_const_eval/src/util/type_name.rs b/compiler/rustc_const_eval/src/util/type_name.rs
index 5bcf96abd8c..db651811551 100644
--- a/compiler/rustc_const_eval/src/util/type_name.rs
+++ b/compiler/rustc_const_eval/src/util/type_name.rs
@@ -41,7 +41,7 @@ impl<'tcx> Printer<'tcx> for TypeNamePrinter<'tcx> {
             | ty::FnPtr(..)
             | ty::Never
             | ty::Tuple(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::UnsafeBinder(_) => self.pretty_print_type(ty),
 
             // Placeholders (all printed as `_` to uniformize them).
diff --git a/compiler/rustc_hir_analysis/src/collect/dump.rs b/compiler/rustc_hir_analysis/src/collect/dump.rs
index c3f965d8456..44cc2dec1cb 100644
--- a/compiler/rustc_hir_analysis/src/collect/dump.rs
+++ b/compiler/rustc_hir_analysis/src/collect/dump.rs
@@ -152,7 +152,7 @@ pub(crate) fn vtables<'tcx>(tcx: TyCtxt<'tcx>) {
                     );
                     continue;
                 };
-                let ty::Dynamic(data, _, _) = *ty.kind() else {
+                let ty::Dynamic(data, _) = *ty.kind() else {
                     tcx.dcx()
                         .span_err(attr.span(), "`rustc_dump_vtable` to type alias of dyn type");
                     continue;
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs
index 76bb59e3f09..c248cd7fec2 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs
@@ -1,16 +1,22 @@
+use rustc_ast::TraitObjectSyntax;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
-use rustc_errors::struct_span_code_err;
+use rustc_errors::{
+    Applicability, Diag, EmissionGuarantee, StashKey, Suggestions, struct_span_code_err,
+};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_lint_defs::builtin::UNUSED_ASSOCIATED_TYPE_BOUNDS;
+use rustc_hir::def_id::DefId;
+use rustc_lint_defs::builtin::{BARE_TRAIT_OBJECTS, UNUSED_ASSOCIATED_TYPE_BOUNDS};
 use rustc_middle::ty::elaborate::ClauseWithSupertraitSpan;
 use rustc_middle::ty::{
-    self, BottomUpFolder, DynKind, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable,
+    self, BottomUpFolder, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable,
     TypeVisitableExt, Upcast,
 };
+use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::error_reporting::traits::report_dyn_incompatibility;
+use rustc_trait_selection::error_reporting::traits::suggestions::NextTypeParamName;
 use rustc_trait_selection::traits;
 use smallvec::{SmallVec, smallvec};
 use tracing::{debug, instrument};
@@ -28,11 +34,24 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         hir_id: hir::HirId,
         hir_bounds: &[hir::PolyTraitRef<'tcx>],
         lifetime: &hir::Lifetime,
-        representation: DynKind,
+        syntax: TraitObjectSyntax,
     ) -> Ty<'tcx> {
         let tcx = self.tcx();
         let dummy_self = tcx.types.trait_object_dummy_self;
 
+        match syntax {
+            TraitObjectSyntax::Dyn => {}
+            TraitObjectSyntax::None => {
+                match self.prohibit_or_lint_bare_trait_object_ty(span, hir_id, hir_bounds) {
+                    // Don't continue with type analysis if the `dyn` keyword is missing.
+                    // It generates confusing errors, especially if the user meant to use
+                    // another keyword like `impl`.
+                    Some(guar) => return Ty::new_error(tcx, guar),
+                    None => {}
+                }
+            }
+        }
+
         let mut user_written_bounds = Vec::new();
         let mut potential_assoc_types = Vec::new();
         for poly_trait_ref in hir_bounds.iter() {
@@ -47,10 +66,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             }
         }
 
-        let ast_bounds: Vec<_> =
-            hir_bounds.iter().map(|&trait_ref| hir::GenericBound::Trait(trait_ref)).collect();
-
-        self.add_default_traits(&mut user_written_bounds, dummy_self, &ast_bounds, None, span);
+        self.add_default_traits(
+            &mut user_written_bounds,
+            dummy_self,
+            &hir_bounds
+                .iter()
+                .map(|&trait_ref| hir::GenericBound::Trait(trait_ref))
+                .collect::<Vec<_>>(),
+            None,
+            span,
+        );
 
         let (elaborated_trait_bounds, elaborated_projection_bounds) =
             traits::expand_trait_aliases(tcx, user_written_bounds.iter().copied());
@@ -431,7 +456,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         };
         debug!(?region_bound);
 
-        Ty::new_dynamic(tcx, existential_predicates, region_bound, representation)
+        Ty::new_dynamic(tcx, existential_predicates, region_bound)
     }
 
     /// Check that elaborating the principal of a trait ref doesn't lead to projections
@@ -483,6 +508,521 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             },
         );
     }
+
+    /// Prohibit or lint against *bare* trait object types depending on the edition.
+    ///
+    /// *Bare* trait object types are ones that aren't preceded by the keyword `dyn`.
+    /// In edition 2021 and onward we emit a hard error for them.
+    fn prohibit_or_lint_bare_trait_object_ty(
+        &self,
+        span: Span,
+        hir_id: hir::HirId,
+        hir_bounds: &[hir::PolyTraitRef<'tcx>],
+    ) -> Option<ErrorGuaranteed> {
+        let tcx = self.tcx();
+        let [poly_trait_ref, ..] = hir_bounds else { return None };
+
+        let in_path = match tcx.parent_hir_node(hir_id) {
+            hir::Node::Ty(hir::Ty {
+                kind: hir::TyKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            })
+            | hir::Node::Expr(hir::Expr {
+                kind: hir::ExprKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            })
+            | hir::Node::PatExpr(hir::PatExpr {
+                kind: hir::PatExprKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            }) if qself.hir_id == hir_id => true,
+            _ => false,
+        };
+        let needs_bracket = in_path
+            && !tcx
+                .sess
+                .source_map()
+                .span_to_prev_source(span)
+                .ok()
+                .is_some_and(|s| s.trim_end().ends_with('<'));
+
+        let is_global = poly_trait_ref.trait_ref.path.is_global();
+
+        let mut sugg = vec![(
+            span.shrink_to_lo(),
+            format!(
+                "{}dyn {}",
+                if needs_bracket { "<" } else { "" },
+                if is_global { "(" } else { "" },
+            ),
+        )];
+
+        if is_global || needs_bracket {
+            sugg.push((
+                span.shrink_to_hi(),
+                format!(
+                    "{}{}",
+                    if is_global { ")" } else { "" },
+                    if needs_bracket { ">" } else { "" },
+                ),
+            ));
+        }
+
+        if span.edition().at_least_rust_2021() {
+            let mut diag = rustc_errors::struct_span_code_err!(
+                self.dcx(),
+                span,
+                E0782,
+                "{}",
+                "expected a type, found a trait"
+            );
+            if span.can_be_used_for_suggestions()
+                && poly_trait_ref.trait_ref.trait_def_id().is_some()
+                && !self.maybe_suggest_impl_trait(span, hir_id, hir_bounds, &mut diag)
+                && !self.maybe_suggest_dyn_trait(hir_id, sugg, &mut diag)
+            {
+                self.maybe_suggest_add_generic_impl_trait(span, hir_id, &mut diag);
+            }
+            // Check if the impl trait that we are considering is an impl of a local trait.
+            self.maybe_suggest_blanket_trait_impl(span, hir_id, &mut diag);
+            self.maybe_suggest_assoc_ty_bound(hir_id, &mut diag);
+            self.maybe_suggest_typoed_method(
+                hir_id,
+                poly_trait_ref.trait_ref.trait_def_id(),
+                &mut diag,
+            );
+            // In case there is an associated type with the same name
+            // Add the suggestion to this error
+            if let Some(mut sugg) =
+                self.dcx().steal_non_err(span, StashKey::AssociatedTypeSuggestion)
+                && let Suggestions::Enabled(ref mut s1) = diag.suggestions
+                && let Suggestions::Enabled(ref mut s2) = sugg.suggestions
+            {
+                s1.append(s2);
+                sugg.cancel();
+            }
+            Some(diag.emit())
+        } else {
+            tcx.node_span_lint(BARE_TRAIT_OBJECTS, hir_id, span, |lint| {
+                lint.primary_message("trait objects without an explicit `dyn` are deprecated");
+                if span.can_be_used_for_suggestions() {
+                    lint.multipart_suggestion_verbose(
+                        "if this is a dyn-compatible trait, use `dyn`",
+                        sugg,
+                        Applicability::MachineApplicable,
+                    );
+                }
+                self.maybe_suggest_blanket_trait_impl(span, hir_id, lint);
+            });
+            None
+        }
+    }
+
+    /// For a struct or enum with an invalid bare trait object field, suggest turning
+    /// it into a generic type bound.
+    fn maybe_suggest_add_generic_impl_trait(
+        &self,
+        span: Span,
+        hir_id: hir::HirId,
+        diag: &mut Diag<'_>,
+    ) -> bool {
+        let tcx = self.tcx();
+
+        let parent_hir_id = tcx.parent_hir_id(hir_id);
+        let parent_item = tcx.hir_get_parent_item(hir_id).def_id;
+
+        let generics = match tcx.hir_node_by_def_id(parent_item) {
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Struct(_, generics, variant),
+                ..
+            }) => {
+                if !variant.fields().iter().any(|field| field.hir_id == parent_hir_id) {
+                    return false;
+                }
+                generics
+            }
+            hir::Node::Item(hir::Item { kind: hir::ItemKind::Enum(_, generics, def), .. }) => {
+                if !def
+                    .variants
+                    .iter()
+                    .flat_map(|variant| variant.data.fields().iter())
+                    .any(|field| field.hir_id == parent_hir_id)
+                {
+                    return false;
+                }
+                generics
+            }
+            _ => return false,
+        };
+
+        let Ok(rendered_ty) = tcx.sess.source_map().span_to_snippet(span) else {
+            return false;
+        };
+
+        let param = "TUV"
+            .chars()
+            .map(|c| c.to_string())
+            .chain((0..).map(|i| format!("P{i}")))
+            .find(|s| !generics.params.iter().any(|param| param.name.ident().as_str() == s))
+            .expect("we definitely can find at least one param name to generate");
+        let mut sugg = vec![(span, param.to_string())];
+        if let Some(insertion_span) = generics.span_for_param_suggestion() {
+            sugg.push((insertion_span, format!(", {param}: {}", rendered_ty)));
+        } else {
+            sugg.push((generics.where_clause_span, format!("<{param}: {}>", rendered_ty)));
+        }
+        diag.multipart_suggestion_verbose(
+            "you might be missing a type parameter",
+            sugg,
+            Applicability::MachineApplicable,
+        );
+        true
+    }
+
+    /// Make sure that we are in the condition to suggest the blanket implementation.
+    fn maybe_suggest_blanket_trait_impl<G: EmissionGuarantee>(
+        &self,
+        span: Span,
+        hir_id: hir::HirId,
+        diag: &mut Diag<'_, G>,
+    ) {
+        let tcx = self.tcx();
+        let parent_id = tcx.hir_get_parent_item(hir_id).def_id;
+        if let hir::Node::Item(hir::Item {
+            kind: hir::ItemKind::Impl(hir::Impl { self_ty: impl_self_ty, of_trait, generics, .. }),
+            ..
+        }) = tcx.hir_node_by_def_id(parent_id)
+            && hir_id == impl_self_ty.hir_id
+        {
+            let Some(of_trait) = of_trait else {
+                diag.span_suggestion_verbose(
+                    impl_self_ty.span.shrink_to_hi(),
+                    "you might have intended to implement this trait for a given type",
+                    format!(" for /* Type */"),
+                    Applicability::HasPlaceholders,
+                );
+                return;
+            };
+            if !of_trait.trait_ref.trait_def_id().is_some_and(|def_id| def_id.is_local()) {
+                return;
+            }
+            let of_trait_span = of_trait.trait_ref.path.span;
+            // make sure that we are not calling unwrap to abort during the compilation
+            let Ok(of_trait_name) = tcx.sess.source_map().span_to_snippet(of_trait_span) else {
+                return;
+            };
+
+            let Ok(impl_trait_name) = self.tcx().sess.source_map().span_to_snippet(span) else {
+                return;
+            };
+            let sugg = self.add_generic_param_suggestion(generics, span, &impl_trait_name);
+            diag.multipart_suggestion(
+                format!(
+                    "alternatively use a blanket implementation to implement `{of_trait_name}` for \
+                     all types that also implement `{impl_trait_name}`"
+                ),
+                sugg,
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
+
+    /// Try our best to approximate when adding `dyn` would be helpful for a bare
+    /// trait object.
+    ///
+    /// Right now, this is if the type is either directly nested in another ty,
+    /// or if it's in the tail field within a struct. This approximates what the
+    /// user would've gotten on edition 2015, except for the case where we have
+    /// an *obvious* knock-on `Sized` error.
+    fn maybe_suggest_dyn_trait(
+        &self,
+        hir_id: hir::HirId,
+        sugg: Vec<(Span, String)>,
+        diag: &mut Diag<'_>,
+    ) -> bool {
+        let tcx = self.tcx();
+
+        // Look at the direct HIR parent, since we care about the relationship between
+        // the type and the thing that directly encloses it.
+        match tcx.parent_hir_node(hir_id) {
+            // These are all generally ok. Namely, when a trait object is nested
+            // into another expression or ty, it's either very certain that they
+            // missed the ty (e.g. `&Trait`) or it's not really possible to tell
+            // what their intention is, so let's not give confusing suggestions and
+            // just mention `dyn`. The user can make up their mind what to do here.
+            hir::Node::Ty(_)
+            | hir::Node::Expr(_)
+            | hir::Node::PatExpr(_)
+            | hir::Node::PathSegment(_)
+            | hir::Node::AssocItemConstraint(_)
+            | hir::Node::TraitRef(_)
+            | hir::Node::Item(_)
+            | hir::Node::WherePredicate(_) => {}
+
+            hir::Node::Field(field) => {
+                // Enums can't have unsized fields, fields can only have an unsized tail field.
+                if let hir::Node::Item(hir::Item {
+                    kind: hir::ItemKind::Struct(_, _, variant), ..
+                }) = tcx.parent_hir_node(field.hir_id)
+                    && variant
+                        .fields()
+                        .last()
+                        .is_some_and(|tail_field| tail_field.hir_id == field.hir_id)
+                {
+                    // Ok
+                } else {
+                    return false;
+                }
+            }
+            _ => return false,
+        }
+
+        // FIXME: Only emit this suggestion if the trait is dyn-compatible.
+        diag.multipart_suggestion_verbose(
+            "you can add the `dyn` keyword if you want a trait object",
+            sugg,
+            Applicability::MachineApplicable,
+        );
+        true
+    }
+
+    fn add_generic_param_suggestion(
+        &self,
+        generics: &hir::Generics<'_>,
+        self_ty_span: Span,
+        impl_trait_name: &str,
+    ) -> Vec<(Span, String)> {
+        // check if the trait has generics, to make a correct suggestion
+        let param_name = generics.params.next_type_param_name(None);
+
+        let add_generic_sugg = if let Some(span) = generics.span_for_param_suggestion() {
+            (span, format!(", {param_name}: {impl_trait_name}"))
+        } else {
+            (generics.span, format!("<{param_name}: {impl_trait_name}>"))
+        };
+        vec![(self_ty_span, param_name), add_generic_sugg]
+    }
+
+    /// Make sure that we are in the condition to suggest `impl Trait`.
+    fn maybe_suggest_impl_trait(
+        &self,
+        span: Span,
+        hir_id: hir::HirId,
+        hir_bounds: &[hir::PolyTraitRef<'tcx>],
+        diag: &mut Diag<'_>,
+    ) -> bool {
+        let tcx = self.tcx();
+        let parent_id = tcx.hir_get_parent_item(hir_id).def_id;
+        // FIXME: If `type_alias_impl_trait` is enabled, also look for `Trait0<Ty = Trait1>`
+        //        and suggest `Trait0<Ty = impl Trait1>`.
+        // Functions are found in three different contexts.
+        // 1. Independent functions
+        // 2. Functions inside trait blocks
+        // 3. Functions inside impl blocks
+        let (sig, generics) = match tcx.hir_node_by_def_id(parent_id) {
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Fn { sig, generics, .. }, ..
+            }) => (sig, generics),
+            hir::Node::TraitItem(hir::TraitItem {
+                kind: hir::TraitItemKind::Fn(sig, _),
+                generics,
+                ..
+            }) => (sig, generics),
+            hir::Node::ImplItem(hir::ImplItem {
+                kind: hir::ImplItemKind::Fn(sig, _),
+                generics,
+                ..
+            }) => (sig, generics),
+            _ => return false,
+        };
+        let Ok(trait_name) = tcx.sess.source_map().span_to_snippet(span) else {
+            return false;
+        };
+        let impl_sugg = vec![(span.shrink_to_lo(), "impl ".to_string())];
+        // Check if trait object is safe for suggesting dynamic dispatch.
+        let is_dyn_compatible = hir_bounds.iter().all(|bound| match bound.trait_ref.path.res {
+            Res::Def(DefKind::Trait, id) => tcx.is_dyn_compatible(id),
+            _ => false,
+        });
+
+        let borrowed = matches!(
+            tcx.parent_hir_node(hir_id),
+            hir::Node::Ty(hir::Ty { kind: hir::TyKind::Ref(..), .. })
+        );
+
+        // Suggestions for function return type.
+        if let hir::FnRetTy::Return(ty) = sig.decl.output
+            && ty.peel_refs().hir_id == hir_id
+        {
+            let pre = if !is_dyn_compatible {
+                format!("`{trait_name}` is dyn-incompatible, ")
+            } else {
+                String::new()
+            };
+            let msg = format!(
+                "{pre}use `impl {trait_name}` to return an opaque type, as long as you return a \
+                 single underlying type",
+            );
+
+            diag.multipart_suggestion_verbose(msg, impl_sugg, Applicability::MachineApplicable);
+
+            // Suggest `Box<dyn Trait>` for return type
+            if is_dyn_compatible {
+                // If the return type is `&Trait`, we don't want
+                // the ampersand to be displayed in the `Box<dyn Trait>`
+                // suggestion.
+                let suggestion = if borrowed {
+                    vec![(ty.span, format!("Box<dyn {trait_name}>"))]
+                } else {
+                    vec![
+                        (ty.span.shrink_to_lo(), "Box<dyn ".to_string()),
+                        (ty.span.shrink_to_hi(), ">".to_string()),
+                    ]
+                };
+
+                diag.multipart_suggestion_verbose(
+                    "alternatively, you can return an owned trait object",
+                    suggestion,
+                    Applicability::MachineApplicable,
+                );
+            }
+            return true;
+        }
+
+        // Suggestions for function parameters.
+        for ty in sig.decl.inputs {
+            if ty.peel_refs().hir_id != hir_id {
+                continue;
+            }
+            let sugg = self.add_generic_param_suggestion(generics, span, &trait_name);
+            diag.multipart_suggestion_verbose(
+                format!("use a new generic type parameter, constrained by `{trait_name}`"),
+                sugg,
+                Applicability::MachineApplicable,
+            );
+            diag.multipart_suggestion_verbose(
+                "you can also use an opaque type, but users won't be able to specify the type \
+                 parameter when calling the `fn`, having to rely exclusively on type inference",
+                impl_sugg,
+                Applicability::MachineApplicable,
+            );
+            if !is_dyn_compatible {
+                diag.note(format!(
+                    "`{trait_name}` is dyn-incompatible, otherwise a trait object could be used"
+                ));
+            } else {
+                // No ampersand in suggestion if it's borrowed already
+                let (dyn_str, paren_dyn_str) =
+                    if borrowed { ("dyn ", "(dyn ") } else { ("&dyn ", "&(dyn ") };
+
+                let sugg = if let [_, _, ..] = hir_bounds {
+                    // There is more than one trait bound, we need surrounding parentheses.
+                    vec![
+                        (span.shrink_to_lo(), paren_dyn_str.to_string()),
+                        (span.shrink_to_hi(), ")".to_string()),
+                    ]
+                } else {
+                    vec![(span.shrink_to_lo(), dyn_str.to_string())]
+                };
+                diag.multipart_suggestion_verbose(
+                    format!(
+                        "alternatively, use a trait object to accept any type that implements \
+                         `{trait_name}`, accessing its methods at runtime using dynamic dispatch",
+                    ),
+                    sugg,
+                    Applicability::MachineApplicable,
+                );
+            }
+            return true;
+        }
+        false
+    }
+
+    fn maybe_suggest_assoc_ty_bound(&self, hir_id: hir::HirId, diag: &mut Diag<'_>) {
+        let mut parents = self.tcx().hir_parent_iter(hir_id);
+
+        if let Some((c_hir_id, hir::Node::AssocItemConstraint(constraint))) = parents.next()
+            && let Some(obj_ty) = constraint.ty()
+            && let Some((_, hir::Node::TraitRef(trait_ref))) = parents.next()
+        {
+            if let Some((_, hir::Node::Ty(ty))) = parents.next()
+                && let hir::TyKind::TraitObject(..) = ty.kind
+            {
+                // Assoc ty bounds aren't permitted inside trait object types.
+                return;
+            }
+
+            if trait_ref
+                .path
+                .segments
+                .iter()
+                .find_map(|seg| {
+                    seg.args.filter(|args| args.constraints.iter().any(|c| c.hir_id == c_hir_id))
+                })
+                .is_none_or(|args| args.parenthesized != hir::GenericArgsParentheses::No)
+            {
+                // Only consider angle-bracketed args (where we have a `=` to replace with `:`).
+                return;
+            }
+
+            let lo = if constraint.gen_args.span_ext.is_dummy() {
+                constraint.ident.span
+            } else {
+                constraint.gen_args.span_ext
+            };
+            let hi = obj_ty.span;
+
+            if !lo.eq_ctxt(hi) {
+                return;
+            }
+
+            diag.span_suggestion_verbose(
+                lo.between(hi),
+                "you might have meant to write a bound here",
+                ": ",
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
+
+    fn maybe_suggest_typoed_method(
+        &self,
+        hir_id: hir::HirId,
+        trait_def_id: Option<DefId>,
+        diag: &mut Diag<'_>,
+    ) {
+        let tcx = self.tcx();
+        let Some(trait_def_id) = trait_def_id else {
+            return;
+        };
+        let hir::Node::Expr(hir::Expr {
+            kind: hir::ExprKind::Path(hir::QPath::TypeRelative(path_ty, segment)),
+            ..
+        }) = tcx.parent_hir_node(hir_id)
+        else {
+            return;
+        };
+        if path_ty.hir_id != hir_id {
+            return;
+        }
+        let names: Vec<_> = tcx
+            .associated_items(trait_def_id)
+            .in_definition_order()
+            .filter(|assoc| assoc.namespace() == hir::def::Namespace::ValueNS)
+            .map(|cand| cand.name())
+            .collect();
+        if let Some(typo) = find_best_match_for_name(&names, segment.ident.name, None) {
+            diag.span_suggestion_verbose(
+                segment.ident.span,
+                format!(
+                    "you may have misspelled this associated item, causing `{}` \
+                    to be interpreted as a type rather than a trait",
+                    tcx.item_name(trait_def_id),
+                ),
+                typo,
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
 }
 
 fn replace_dummy_self_with_error<'tcx, T: TypeFoldable<TyCtxt<'tcx>>>(
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
index 0cf9cb7193f..16505174464 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
@@ -859,7 +859,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     bound_spans.get_mut_or_insert_default(tcx.def_span(def.did())).push(msg)
                 }
                 // Point at the trait object that couldn't satisfy the bound.
-                ty::Dynamic(preds, _, _) => {
+                ty::Dynamic(preds, _) => {
                     for pred in preds.iter() {
                         match pred.skip_binder() {
                             ty::ExistentialPredicate::Trait(tr) => {
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
deleted file mode 100644
index 56998b5b53c..00000000000
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
+++ /dev/null
@@ -1,533 +0,0 @@
-use rustc_ast::TraitObjectSyntax;
-use rustc_errors::codes::*;
-use rustc_errors::{Diag, EmissionGuarantee, ErrorGuaranteed, StashKey, Suggestions};
-use rustc_hir as hir;
-use rustc_hir::def::{DefKind, Namespace, Res};
-use rustc_hir::def_id::DefId;
-use rustc_lint_defs::Applicability;
-use rustc_lint_defs::builtin::BARE_TRAIT_OBJECTS;
-use rustc_span::Span;
-use rustc_span::edit_distance::find_best_match_for_name;
-use rustc_trait_selection::error_reporting::traits::suggestions::NextTypeParamName;
-
-use super::HirTyLowerer;
-
-impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
-    /// Prohibit or lint against *bare* trait object types depending on the edition.
-    ///
-    /// *Bare* trait object types are ones that aren't preceded by the keyword `dyn`.
-    /// In edition 2021 and onward we emit a hard error for them.
-    pub(super) fn prohibit_or_lint_bare_trait_object_ty(
-        &self,
-        self_ty: &hir::Ty<'_>,
-    ) -> Option<ErrorGuaranteed> {
-        let tcx = self.tcx();
-
-        let poly_trait_ref = if let hir::TyKind::TraitObject([poly_trait_ref, ..], tagged_ptr) =
-            self_ty.kind
-            && let TraitObjectSyntax::None = tagged_ptr.tag()
-        {
-            poly_trait_ref
-        } else {
-            return None;
-        };
-
-        let in_path = match tcx.parent_hir_node(self_ty.hir_id) {
-            hir::Node::Ty(hir::Ty {
-                kind: hir::TyKind::Path(hir::QPath::TypeRelative(qself, _)),
-                ..
-            })
-            | hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Path(hir::QPath::TypeRelative(qself, _)),
-                ..
-            })
-            | hir::Node::PatExpr(hir::PatExpr {
-                kind: hir::PatExprKind::Path(hir::QPath::TypeRelative(qself, _)),
-                ..
-            }) if qself.hir_id == self_ty.hir_id => true,
-            _ => false,
-        };
-        let needs_bracket = in_path
-            && !tcx
-                .sess
-                .source_map()
-                .span_to_prev_source(self_ty.span)
-                .ok()
-                .is_some_and(|s| s.trim_end().ends_with('<'));
-
-        let is_global = poly_trait_ref.trait_ref.path.is_global();
-
-        let mut sugg = vec![(
-            self_ty.span.shrink_to_lo(),
-            format!(
-                "{}dyn {}",
-                if needs_bracket { "<" } else { "" },
-                if is_global { "(" } else { "" },
-            ),
-        )];
-
-        if is_global || needs_bracket {
-            sugg.push((
-                self_ty.span.shrink_to_hi(),
-                format!(
-                    "{}{}",
-                    if is_global { ")" } else { "" },
-                    if needs_bracket { ">" } else { "" },
-                ),
-            ));
-        }
-
-        if self_ty.span.edition().at_least_rust_2021() {
-            let mut diag = rustc_errors::struct_span_code_err!(
-                self.dcx(),
-                self_ty.span,
-                E0782,
-                "{}",
-                "expected a type, found a trait"
-            );
-            if self_ty.span.can_be_used_for_suggestions()
-                && poly_trait_ref.trait_ref.trait_def_id().is_some()
-                && !self.maybe_suggest_impl_trait(self_ty, &mut diag)
-                && !self.maybe_suggest_dyn_trait(self_ty, sugg, &mut diag)
-            {
-                self.maybe_suggest_add_generic_impl_trait(self_ty, &mut diag);
-            }
-            // Check if the impl trait that we are considering is an impl of a local trait.
-            self.maybe_suggest_blanket_trait_impl(self_ty, &mut diag);
-            self.maybe_suggest_assoc_ty_bound(self_ty, &mut diag);
-            self.maybe_suggest_typoed_method(
-                self_ty,
-                poly_trait_ref.trait_ref.trait_def_id(),
-                &mut diag,
-            );
-            // In case there is an associated type with the same name
-            // Add the suggestion to this error
-            if let Some(mut sugg) =
-                self.dcx().steal_non_err(self_ty.span, StashKey::AssociatedTypeSuggestion)
-                && let Suggestions::Enabled(ref mut s1) = diag.suggestions
-                && let Suggestions::Enabled(ref mut s2) = sugg.suggestions
-            {
-                s1.append(s2);
-                sugg.cancel();
-            }
-            Some(diag.emit())
-        } else {
-            tcx.node_span_lint(BARE_TRAIT_OBJECTS, self_ty.hir_id, self_ty.span, |lint| {
-                lint.primary_message("trait objects without an explicit `dyn` are deprecated");
-                if self_ty.span.can_be_used_for_suggestions() {
-                    lint.multipart_suggestion_verbose(
-                        "if this is a dyn-compatible trait, use `dyn`",
-                        sugg,
-                        Applicability::MachineApplicable,
-                    );
-                }
-                self.maybe_suggest_blanket_trait_impl(self_ty, lint);
-            });
-            None
-        }
-    }
-
-    /// For a struct or enum with an invalid bare trait object field, suggest turning
-    /// it into a generic type bound.
-    fn maybe_suggest_add_generic_impl_trait(
-        &self,
-        self_ty: &hir::Ty<'_>,
-        diag: &mut Diag<'_>,
-    ) -> bool {
-        let tcx = self.tcx();
-
-        let parent_hir_id = tcx.parent_hir_id(self_ty.hir_id);
-        let parent_item = tcx.hir_get_parent_item(self_ty.hir_id).def_id;
-
-        let generics = match tcx.hir_node_by_def_id(parent_item) {
-            hir::Node::Item(hir::Item {
-                kind: hir::ItemKind::Struct(_, generics, variant),
-                ..
-            }) => {
-                if !variant.fields().iter().any(|field| field.hir_id == parent_hir_id) {
-                    return false;
-                }
-                generics
-            }
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Enum(_, generics, def), .. }) => {
-                if !def
-                    .variants
-                    .iter()
-                    .flat_map(|variant| variant.data.fields().iter())
-                    .any(|field| field.hir_id == parent_hir_id)
-                {
-                    return false;
-                }
-                generics
-            }
-            _ => return false,
-        };
-
-        let Ok(rendered_ty) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
-            return false;
-        };
-
-        let param = "TUV"
-            .chars()
-            .map(|c| c.to_string())
-            .chain((0..).map(|i| format!("P{i}")))
-            .find(|s| !generics.params.iter().any(|param| param.name.ident().as_str() == s))
-            .expect("we definitely can find at least one param name to generate");
-        let mut sugg = vec![(self_ty.span, param.to_string())];
-        if let Some(insertion_span) = generics.span_for_param_suggestion() {
-            sugg.push((insertion_span, format!(", {param}: {}", rendered_ty)));
-        } else {
-            sugg.push((generics.where_clause_span, format!("<{param}: {}>", rendered_ty)));
-        }
-        diag.multipart_suggestion_verbose(
-            "you might be missing a type parameter",
-            sugg,
-            Applicability::MachineApplicable,
-        );
-        true
-    }
-    /// Make sure that we are in the condition to suggest the blanket implementation.
-    fn maybe_suggest_blanket_trait_impl<G: EmissionGuarantee>(
-        &self,
-        self_ty: &hir::Ty<'_>,
-        diag: &mut Diag<'_, G>,
-    ) {
-        let tcx = self.tcx();
-        let parent_id = tcx.hir_get_parent_item(self_ty.hir_id).def_id;
-        if let hir::Node::Item(hir::Item {
-            kind: hir::ItemKind::Impl(hir::Impl { self_ty: impl_self_ty, of_trait, generics, .. }),
-            ..
-        }) = tcx.hir_node_by_def_id(parent_id)
-            && self_ty.hir_id == impl_self_ty.hir_id
-        {
-            let Some(of_trait) = of_trait else {
-                diag.span_suggestion_verbose(
-                    impl_self_ty.span.shrink_to_hi(),
-                    "you might have intended to implement this trait for a given type",
-                    format!(" for /* Type */"),
-                    Applicability::HasPlaceholders,
-                );
-                return;
-            };
-            if !of_trait.trait_ref.trait_def_id().is_some_and(|def_id| def_id.is_local()) {
-                return;
-            }
-            let of_trait_span = of_trait.trait_ref.path.span;
-            // make sure that we are not calling unwrap to abort during the compilation
-            let Ok(of_trait_name) = tcx.sess.source_map().span_to_snippet(of_trait_span) else {
-                return;
-            };
-
-            let Ok(impl_trait_name) = self.tcx().sess.source_map().span_to_snippet(self_ty.span)
-            else {
-                return;
-            };
-            let sugg = self.add_generic_param_suggestion(generics, self_ty.span, &impl_trait_name);
-            diag.multipart_suggestion(
-                format!(
-                    "alternatively use a blanket implementation to implement `{of_trait_name}` for \
-                     all types that also implement `{impl_trait_name}`"
-                ),
-                sugg,
-                Applicability::MaybeIncorrect,
-            );
-        }
-    }
-
-    /// Try our best to approximate when adding `dyn` would be helpful for a bare
-    /// trait object.
-    ///
-    /// Right now, this is if the type is either directly nested in another ty,
-    /// or if it's in the tail field within a struct. This approximates what the
-    /// user would've gotten on edition 2015, except for the case where we have
-    /// an *obvious* knock-on `Sized` error.
-    fn maybe_suggest_dyn_trait(
-        &self,
-        self_ty: &hir::Ty<'_>,
-        sugg: Vec<(Span, String)>,
-        diag: &mut Diag<'_>,
-    ) -> bool {
-        let tcx = self.tcx();
-
-        // Look at the direct HIR parent, since we care about the relationship between
-        // the type and the thing that directly encloses it.
-        match tcx.parent_hir_node(self_ty.hir_id) {
-            // These are all generally ok. Namely, when a trait object is nested
-            // into another expression or ty, it's either very certain that they
-            // missed the ty (e.g. `&Trait`) or it's not really possible to tell
-            // what their intention is, so let's not give confusing suggestions and
-            // just mention `dyn`. The user can make up their mind what to do here.
-            hir::Node::Ty(_)
-            | hir::Node::Expr(_)
-            | hir::Node::PatExpr(_)
-            | hir::Node::PathSegment(_)
-            | hir::Node::AssocItemConstraint(_)
-            | hir::Node::TraitRef(_)
-            | hir::Node::Item(_)
-            | hir::Node::WherePredicate(_) => {}
-
-            hir::Node::Field(field) => {
-                // Enums can't have unsized fields, fields can only have an unsized tail field.
-                if let hir::Node::Item(hir::Item {
-                    kind: hir::ItemKind::Struct(_, _, variant), ..
-                }) = tcx.parent_hir_node(field.hir_id)
-                    && variant
-                        .fields()
-                        .last()
-                        .is_some_and(|tail_field| tail_field.hir_id == field.hir_id)
-                {
-                    // Ok
-                } else {
-                    return false;
-                }
-            }
-            _ => return false,
-        }
-
-        // FIXME: Only emit this suggestion if the trait is dyn-compatible.
-        diag.multipart_suggestion_verbose(
-            "you can add the `dyn` keyword if you want a trait object",
-            sugg,
-            Applicability::MachineApplicable,
-        );
-        true
-    }
-
-    fn add_generic_param_suggestion(
-        &self,
-        generics: &hir::Generics<'_>,
-        self_ty_span: Span,
-        impl_trait_name: &str,
-    ) -> Vec<(Span, String)> {
-        // check if the trait has generics, to make a correct suggestion
-        let param_name = generics.params.next_type_param_name(None);
-
-        let add_generic_sugg = if let Some(span) = generics.span_for_param_suggestion() {
-            (span, format!(", {param_name}: {impl_trait_name}"))
-        } else {
-            (generics.span, format!("<{param_name}: {impl_trait_name}>"))
-        };
-        vec![(self_ty_span, param_name), add_generic_sugg]
-    }
-
-    /// Make sure that we are in the condition to suggest `impl Trait`.
-    fn maybe_suggest_impl_trait(&self, self_ty: &hir::Ty<'_>, diag: &mut Diag<'_>) -> bool {
-        let tcx = self.tcx();
-        let parent_id = tcx.hir_get_parent_item(self_ty.hir_id).def_id;
-        // FIXME: If `type_alias_impl_trait` is enabled, also look for `Trait0<Ty = Trait1>`
-        //        and suggest `Trait0<Ty = impl Trait1>`.
-        // Functions are found in three different contexts.
-        // 1. Independent functions
-        // 2. Functions inside trait blocks
-        // 3. Functions inside impl blocks
-        let (sig, generics) = match tcx.hir_node_by_def_id(parent_id) {
-            hir::Node::Item(hir::Item {
-                kind: hir::ItemKind::Fn { sig, generics, .. }, ..
-            }) => (sig, generics),
-            hir::Node::TraitItem(hir::TraitItem {
-                kind: hir::TraitItemKind::Fn(sig, _),
-                generics,
-                ..
-            }) => (sig, generics),
-            hir::Node::ImplItem(hir::ImplItem {
-                kind: hir::ImplItemKind::Fn(sig, _),
-                generics,
-                ..
-            }) => (sig, generics),
-            _ => return false,
-        };
-        let Ok(trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
-            return false;
-        };
-        let impl_sugg = vec![(self_ty.span.shrink_to_lo(), "impl ".to_string())];
-        // Check if trait object is safe for suggesting dynamic dispatch.
-        let is_dyn_compatible = match self_ty.kind {
-            hir::TyKind::TraitObject(objects, ..) => {
-                objects.iter().all(|o| match o.trait_ref.path.res {
-                    Res::Def(DefKind::Trait, id) => tcx.is_dyn_compatible(id),
-                    _ => false,
-                })
-            }
-            _ => false,
-        };
-
-        let borrowed = matches!(
-            tcx.parent_hir_node(self_ty.hir_id),
-            hir::Node::Ty(hir::Ty { kind: hir::TyKind::Ref(..), .. })
-        );
-
-        // Suggestions for function return type.
-        if let hir::FnRetTy::Return(ty) = sig.decl.output
-            && ty.peel_refs().hir_id == self_ty.hir_id
-        {
-            let pre = if !is_dyn_compatible {
-                format!("`{trait_name}` is dyn-incompatible, ")
-            } else {
-                String::new()
-            };
-            let msg = format!(
-                "{pre}use `impl {trait_name}` to return an opaque type, as long as you return a \
-                 single underlying type",
-            );
-
-            diag.multipart_suggestion_verbose(msg, impl_sugg, Applicability::MachineApplicable);
-
-            // Suggest `Box<dyn Trait>` for return type
-            if is_dyn_compatible {
-                // If the return type is `&Trait`, we don't want
-                // the ampersand to be displayed in the `Box<dyn Trait>`
-                // suggestion.
-                let suggestion = if borrowed {
-                    vec![(ty.span, format!("Box<dyn {trait_name}>"))]
-                } else {
-                    vec![
-                        (ty.span.shrink_to_lo(), "Box<dyn ".to_string()),
-                        (ty.span.shrink_to_hi(), ">".to_string()),
-                    ]
-                };
-
-                diag.multipart_suggestion_verbose(
-                    "alternatively, you can return an owned trait object",
-                    suggestion,
-                    Applicability::MachineApplicable,
-                );
-            }
-            return true;
-        }
-
-        // Suggestions for function parameters.
-        for ty in sig.decl.inputs {
-            if ty.peel_refs().hir_id != self_ty.hir_id {
-                continue;
-            }
-            let sugg = self.add_generic_param_suggestion(generics, self_ty.span, &trait_name);
-            diag.multipart_suggestion_verbose(
-                format!("use a new generic type parameter, constrained by `{trait_name}`"),
-                sugg,
-                Applicability::MachineApplicable,
-            );
-            diag.multipart_suggestion_verbose(
-                "you can also use an opaque type, but users won't be able to specify the type \
-                 parameter when calling the `fn`, having to rely exclusively on type inference",
-                impl_sugg,
-                Applicability::MachineApplicable,
-            );
-            if !is_dyn_compatible {
-                diag.note(format!(
-                    "`{trait_name}` is dyn-incompatible, otherwise a trait object could be used"
-                ));
-            } else {
-                // No ampersand in suggestion if it's borrowed already
-                let (dyn_str, paren_dyn_str) =
-                    if borrowed { ("dyn ", "(dyn ") } else { ("&dyn ", "&(dyn ") };
-
-                let sugg = if let hir::TyKind::TraitObject([_, _, ..], _) = self_ty.kind {
-                    // There is more than one trait bound, we need surrounding parentheses.
-                    vec![
-                        (self_ty.span.shrink_to_lo(), paren_dyn_str.to_string()),
-                        (self_ty.span.shrink_to_hi(), ")".to_string()),
-                    ]
-                } else {
-                    vec![(self_ty.span.shrink_to_lo(), dyn_str.to_string())]
-                };
-                diag.multipart_suggestion_verbose(
-                    format!(
-                        "alternatively, use a trait object to accept any type that implements \
-                         `{trait_name}`, accessing its methods at runtime using dynamic dispatch",
-                    ),
-                    sugg,
-                    Applicability::MachineApplicable,
-                );
-            }
-            return true;
-        }
-        false
-    }
-
-    fn maybe_suggest_assoc_ty_bound(&self, self_ty: &hir::Ty<'_>, diag: &mut Diag<'_>) {
-        let mut parents = self.tcx().hir_parent_iter(self_ty.hir_id);
-
-        if let Some((c_hir_id, hir::Node::AssocItemConstraint(constraint))) = parents.next()
-            && let Some(obj_ty) = constraint.ty()
-            && let Some((_, hir::Node::TraitRef(trait_ref))) = parents.next()
-        {
-            if let Some((_, hir::Node::Ty(ty))) = parents.next()
-                && let hir::TyKind::TraitObject(..) = ty.kind
-            {
-                // Assoc ty bounds aren't permitted inside trait object types.
-                return;
-            }
-
-            if trait_ref
-                .path
-                .segments
-                .iter()
-                .find_map(|seg| {
-                    seg.args.filter(|args| args.constraints.iter().any(|c| c.hir_id == c_hir_id))
-                })
-                .is_none_or(|args| args.parenthesized != hir::GenericArgsParentheses::No)
-            {
-                // Only consider angle-bracketed args (where we have a `=` to replace with `:`).
-                return;
-            }
-
-            let lo = if constraint.gen_args.span_ext.is_dummy() {
-                constraint.ident.span
-            } else {
-                constraint.gen_args.span_ext
-            };
-            let hi = obj_ty.span;
-
-            if !lo.eq_ctxt(hi) {
-                return;
-            }
-
-            diag.span_suggestion_verbose(
-                lo.between(hi),
-                "you might have meant to write a bound here",
-                ": ",
-                Applicability::MaybeIncorrect,
-            );
-        }
-    }
-
-    fn maybe_suggest_typoed_method(
-        &self,
-        self_ty: &hir::Ty<'_>,
-        trait_def_id: Option<DefId>,
-        diag: &mut Diag<'_>,
-    ) {
-        let tcx = self.tcx();
-        let Some(trait_def_id) = trait_def_id else {
-            return;
-        };
-        let hir::Node::Expr(hir::Expr {
-            kind: hir::ExprKind::Path(hir::QPath::TypeRelative(path_ty, segment)),
-            ..
-        }) = tcx.parent_hir_node(self_ty.hir_id)
-        else {
-            return;
-        };
-        if path_ty.hir_id != self_ty.hir_id {
-            return;
-        }
-        let names: Vec<_> = tcx
-            .associated_items(trait_def_id)
-            .in_definition_order()
-            .filter(|assoc| assoc.namespace() == Namespace::ValueNS)
-            .map(|cand| cand.name())
-            .collect();
-        if let Some(typo) = find_best_match_for_name(&names, segment.ident.name, None) {
-            diag.span_suggestion_verbose(
-                segment.ident.span,
-                format!(
-                    "you may have misspelled this associated item, causing `{}` \
-                    to be interpreted as a type rather than a trait",
-                    tcx.item_name(trait_def_id),
-                ),
-                typo,
-                Applicability::MaybeIncorrect,
-            );
-        }
-    }
-}
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index c5e079fe89a..9b198d04454 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -15,15 +15,13 @@
 
 mod bounds;
 mod cmse;
-mod dyn_compatibility;
+mod dyn_trait;
 pub mod errors;
 pub mod generics;
-mod lint;
 
 use std::assert_matches::assert_matches;
 use std::slice;
 
-use rustc_ast::TraitObjectSyntax;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
@@ -2428,19 +2426,8 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             ),
             hir::TyKind::TraitObject(bounds, tagged_ptr) => {
                 let lifetime = tagged_ptr.pointer();
-                let repr = tagged_ptr.tag();
-
-                if let Some(guar) = self.prohibit_or_lint_bare_trait_object_ty(hir_ty) {
-                    // Don't continue with type analysis if the `dyn` keyword is missing
-                    // It generates confusing errors, especially if the user meant to use another
-                    // keyword like `impl`
-                    Ty::new_error(tcx, guar)
-                } else {
-                    let repr = match repr {
-                        TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
-                    };
-                    self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, repr)
-                }
+                let syntax = tagged_ptr.tag();
+                self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, syntax)
             }
             // If we encounter a fully qualified path with RTN generics, then it must have
             // *not* gone through `lower_ty_maybe_return_type_notation`, and therefore
diff --git a/compiler/rustc_hir_analysis/src/variance/constraints.rs b/compiler/rustc_hir_analysis/src/variance/constraints.rs
index 960ec7f66ab..be841675821 100644
--- a/compiler/rustc_hir_analysis/src/variance/constraints.rs
+++ b/compiler/rustc_hir_analysis/src/variance/constraints.rs
@@ -281,7 +281,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_args(current, data.def_id, data.args, variance);
             }
 
-            ty::Dynamic(data, r, _) => {
+            ty::Dynamic(data, r) => {
                 // The type `dyn Trait<T> +'a` is covariant w/r/t `'a`:
                 self.add_constraints_from_region(current, r, variance);
 
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs
index 27540fd1a43..40b21c45bc5 100644
--- a/compiler/rustc_hir_typeck/src/cast.rs
+++ b/compiler/rustc_hir_typeck/src/cast.rs
@@ -103,7 +103,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         Ok(match *t.kind() {
             ty::Slice(_) | ty::Str => Some(PointerKind::Length),
-            ty::Dynamic(tty, _, ty::Dyn) => Some(PointerKind::VTable(tty)),
+            ty::Dynamic(tty, _) => Some(PointerKind::VTable(tty)),
             ty::Adt(def, args) if def.is_struct() => match def.non_enum_variant().tail_opt() {
                 None => Some(PointerKind::Thin),
                 Some(f) => {
@@ -250,9 +250,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
         // cases now. We do a more thorough check at the end, once
         // inference is more completely known.
         match cast_ty.kind() {
-            ty::Dynamic(_, _, ty::Dyn) | ty::Slice(..) => {
-                Err(check.report_cast_to_unsized_type(fcx))
-            }
+            ty::Dynamic(_, _) | ty::Slice(..) => Err(check.report_cast_to_unsized_type(fcx)),
             _ => Ok(check),
         }
     }
@@ -900,7 +898,6 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                                 &src_tty.without_auto_traits().collect::<Vec<_>>(),
                             ),
                             tcx.lifetimes.re_erased,
-                            ty::Dyn,
                         );
                         let dst_obj = Ty::new_dynamic(
                             tcx,
@@ -908,7 +905,6 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                                 &dst_tty.without_auto_traits().collect::<Vec<_>>(),
                             ),
                             tcx.lifetimes.re_erased,
-                            ty::Dyn,
                         );
 
                         // `dyn Src = dyn Dst`, this checks for matching traits/generics/projections
diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs
index b99f811db1a..ced2cf2b57b 100644
--- a/compiler/rustc_hir_typeck/src/coercion.rs
+++ b/compiler/rustc_hir_typeck/src/coercion.rs
@@ -558,7 +558,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             | ty::Slice(_)
             | ty::FnDef(_, _)
             | ty::FnPtr(_, _)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(_, _)
             | ty::CoroutineClosure(_, _)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index c8f6c06b720..a39ac0fcb6e 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -1008,7 +1008,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         bound_spans.get_mut_or_insert_default(tcx.def_span(def.did())).push(msg)
                     }
                     // Point at the trait object that couldn't satisfy the bound.
-                    ty::Dynamic(preds, _, _) => {
+                    ty::Dynamic(preds, _) => {
                         for pred in preds.iter() {
                             match pred.skip_binder() {
                                 ty::ExistentialPredicate::Trait(tr) => {
diff --git a/compiler/rustc_lint/src/deref_into_dyn_supertrait.rs b/compiler/rustc_lint/src/deref_into_dyn_supertrait.rs
index e1c51ff8299..703f757abd5 100644
--- a/compiler/rustc_lint/src/deref_into_dyn_supertrait.rs
+++ b/compiler/rustc_lint/src/deref_into_dyn_supertrait.rs
@@ -66,11 +66,11 @@ impl<'tcx> LateLintPass<'tcx> for DerefIntoDynSupertrait {
             && tcx.is_lang_item(did, LangItem::Deref)
             // the self type is `dyn t_principal`
             && let self_ty = tcx.type_of(item.owner_id).instantiate_identity()
-            && let ty::Dynamic(data, _, ty::Dyn) = self_ty.kind()
+            && let ty::Dynamic(data, _) = self_ty.kind()
             && let Some(self_principal) = data.principal()
             // `<T as Deref>::Target` is `dyn target_principal`
             && let Some(target) = cx.get_associated_type(self_ty, did, sym::Target)
-            && let ty::Dynamic(data, _, ty::Dyn) = target.kind()
+            && let ty::Dynamic(data, _) = target.kind()
             && let Some(target_principal) = data.principal()
             // `target_principal` is a supertrait of `t_principal`
             && let Some(supertrait_principal) = supertraits(tcx, self_principal.with_self_ty(tcx, self_ty))
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index 88527fa2e6e..eaec0c9857d 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -320,7 +320,7 @@ fn lint_wide_pointer<'tcx>(
         };
 
         (!ty.is_sized(cx.tcx, cx.typing_env()))
-            .then(|| (refs, modifiers, matches!(ty.kind(), ty::Dynamic(_, _, ty::Dyn))))
+            .then(|| (refs, modifiers, matches!(ty.kind(), ty::Dynamic(_, _))))
     };
 
     // the left and right operands can have references, remove any explicit references
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index edbbfba4f34..874c4354029 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -312,7 +312,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                         })
                         .map(|inner| MustUsePath::Opaque(Box::new(inner)))
                 }
-                ty::Dynamic(binders, _, _) => binders.iter().find_map(|predicate| {
+                ty::Dynamic(binders, _) => binders.iter().find_map(|predicate| {
                     if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder()
                     {
                         let def_id = trait_ref.def_id;
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 79700d485c4..7d3e2c9965d 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -574,7 +574,7 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
             | ty::Ref(_, _, _)
             | ty::FnDef(_, _)
             | ty::FnPtr(..)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 2114d080dfa..9524057eebc 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -812,7 +812,7 @@ where
                 | ty::CoroutineWitness(..)
                 | ty::Foreign(..)
                 | ty::Pat(_, _)
-                | ty::Dynamic(_, _, ty::Dyn) => {
+                | ty::Dynamic(_, _) => {
                     bug!("TyAndLayout::field({:?}): not applicable", this)
                 }
 
@@ -878,7 +878,7 @@ where
                         // `std::mem::uninitialized::<&dyn Trait>()`, for example.
                         if let ty::Adt(def, args) = metadata.kind()
                             && tcx.is_lang_item(def.did(), LangItem::DynMetadata)
-                            && let ty::Dynamic(data, _, ty::Dyn) = args.type_at(0).kind()
+                            && let ty::Dynamic(data, _) = args.type_at(0).kind()
                         {
                             mk_dyn_vtable(data.principal())
                         } else {
@@ -887,7 +887,7 @@ where
                     } else {
                         match tcx.struct_tail_for_codegen(pointee, cx.typing_env()).kind() {
                             ty::Slice(_) | ty::Str => tcx.types.usize,
-                            ty::Dynamic(data, _, ty::Dyn) => mk_dyn_vtable(data.principal()),
+                            ty::Dynamic(data, _) => mk_dyn_vtable(data.principal()),
                             _ => bug!("TyAndLayout::field({:?}): not applicable", this),
                         }
                     };
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index fc821ffdaa6..1b7ef8de845 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -784,14 +784,12 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                 },
             },
             ty::Adt(def, args) => self.print_def_path(def.did(), args)?,
-            ty::Dynamic(data, r, repr) => {
+            ty::Dynamic(data, r) => {
                 let print_r = self.should_print_optional_region(r);
                 if print_r {
                     write!(self, "(")?;
                 }
-                match repr {
-                    ty::Dyn => write!(self, "dyn ")?,
-                }
+                write!(self, "dyn ")?;
                 data.print(self)?;
                 if print_r {
                     write!(self, " + ")?;
diff --git a/compiler/rustc_middle/src/ty/significant_drop_order.rs b/compiler/rustc_middle/src/ty/significant_drop_order.rs
index 5ada9ecc80c..f1aa7076d98 100644
--- a/compiler/rustc_middle/src/ty/significant_drop_order.rs
+++ b/compiler/rustc_middle/src/ty/significant_drop_order.rs
@@ -132,7 +132,7 @@ pub fn ty_dtor_span<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<Span> {
         | ty::Ref(_, _, _)
         | ty::FnPtr(_, _)
         | ty::Tuple(_)
-        | ty::Dynamic(_, _, _)
+        | ty::Dynamic(_, _)
         | ty::Alias(_, _)
         | ty::Bound(_, _)
         | ty::Pat(_, _)
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 89ef46b1ae5..11d109b463d 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -390,11 +390,9 @@ impl<'tcx> TypeSuperFoldable<TyCtxt<'tcx>> for Ty<'tcx> {
             ty::Array(typ, sz) => ty::Array(typ.try_fold_with(folder)?, sz.try_fold_with(folder)?),
             ty::Slice(typ) => ty::Slice(typ.try_fold_with(folder)?),
             ty::Adt(tid, args) => ty::Adt(tid, args.try_fold_with(folder)?),
-            ty::Dynamic(trait_ty, region, representation) => ty::Dynamic(
-                trait_ty.try_fold_with(folder)?,
-                region.try_fold_with(folder)?,
-                representation,
-            ),
+            ty::Dynamic(trait_ty, region) => {
+                ty::Dynamic(trait_ty.try_fold_with(folder)?, region.try_fold_with(folder)?)
+            }
             ty::Tuple(ts) => ty::Tuple(ts.try_fold_with(folder)?),
             ty::FnDef(def_id, args) => ty::FnDef(def_id, args.try_fold_with(folder)?),
             ty::FnPtr(sig_tys, hdr) => ty::FnPtr(sig_tys.try_fold_with(folder)?, hdr),
@@ -437,8 +435,8 @@ impl<'tcx> TypeSuperFoldable<TyCtxt<'tcx>> for Ty<'tcx> {
             ty::Array(typ, sz) => ty::Array(typ.fold_with(folder), sz.fold_with(folder)),
             ty::Slice(typ) => ty::Slice(typ.fold_with(folder)),
             ty::Adt(tid, args) => ty::Adt(tid, args.fold_with(folder)),
-            ty::Dynamic(trait_ty, region, representation) => {
-                ty::Dynamic(trait_ty.fold_with(folder), region.fold_with(folder), representation)
+            ty::Dynamic(trait_ty, region) => {
+                ty::Dynamic(trait_ty.fold_with(folder), region.fold_with(folder))
             }
             ty::Tuple(ts) => ty::Tuple(ts.fold_with(folder)),
             ty::FnDef(def_id, args) => ty::FnDef(def_id, args.fold_with(folder)),
@@ -481,7 +479,7 @@ impl<'tcx> TypeSuperVisitable<TyCtxt<'tcx>> for Ty<'tcx> {
             }
             ty::Slice(typ) => typ.visit_with(visitor),
             ty::Adt(_, args) => args.visit_with(visitor),
-            ty::Dynamic(trait_ty, reg, _) => {
+            ty::Dynamic(trait_ty, reg) => {
                 try_visit!(trait_ty.visit_with(visitor));
                 reg.visit_with(visitor)
             }
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 755fc68d86f..2bea7977999 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -17,7 +17,7 @@ use rustc_span::{DUMMY_SP, Span, Symbol, sym};
 use rustc_type_ir::TyKind::*;
 use rustc_type_ir::solve::SizedTraitKind;
 use rustc_type_ir::walk::TypeWalker;
-use rustc_type_ir::{self as ir, BoundVar, CollectAndApply, DynKind, TypeVisitableExt, elaborate};
+use rustc_type_ir::{self as ir, BoundVar, CollectAndApply, TypeVisitableExt, elaborate};
 use tracing::instrument;
 use ty::util::IntTypeExt;
 
@@ -734,7 +734,6 @@ impl<'tcx> Ty<'tcx> {
         tcx: TyCtxt<'tcx>,
         obj: &'tcx List<ty::PolyExistentialPredicate<'tcx>>,
         reg: ty::Region<'tcx>,
-        repr: DynKind,
     ) -> Ty<'tcx> {
         if cfg!(debug_assertions) {
             let projection_count = obj
@@ -767,7 +766,7 @@ impl<'tcx> Ty<'tcx> {
                 but it has {projection_count}"
             );
         }
-        Ty::new(tcx, Dynamic(obj, reg, repr))
+        Ty::new(tcx, Dynamic(obj, reg))
     }
 
     #[inline]
@@ -980,9 +979,8 @@ impl<'tcx> rustc_type_ir::inherent::Ty<TyCtxt<'tcx>> for Ty<'tcx> {
         interner: TyCtxt<'tcx>,
         preds: &'tcx List<ty::PolyExistentialPredicate<'tcx>>,
         region: ty::Region<'tcx>,
-        kind: ty::DynKind,
     ) -> Self {
-        Ty::new_dynamic(interner, preds, region, kind)
+        Ty::new_dynamic(interner, preds, region)
     }
 
     fn new_coroutine(
@@ -1356,7 +1354,7 @@ impl<'tcx> Ty<'tcx> {
 
     #[inline]
     pub fn is_trait(self) -> bool {
-        matches!(self.kind(), Dynamic(_, _, ty::Dyn))
+        matches!(self.kind(), Dynamic(_, _))
     }
 
     #[inline]
@@ -1671,7 +1669,7 @@ impl<'tcx> Ty<'tcx> {
 
             ty::Str | ty::Slice(_) => Ok(tcx.types.usize),
 
-            ty::Dynamic(_, _, ty::Dyn) => {
+            ty::Dynamic(_, _) => {
                 let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, DUMMY_SP);
                 Ok(tcx.type_of(dyn_metadata).instantiate(tcx, &[tail.into()]))
             }
@@ -1853,7 +1851,7 @@ impl<'tcx> Ty<'tcx> {
             | ty::Never
             | ty::Error(_) => true,
 
-            ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) => match sizedness {
+            ty::Str | ty::Slice(_) | ty::Dynamic(_, _) => match sizedness {
                 SizedTraitKind::Sized => false,
                 SizedTraitKind::MetaSized => true,
             },
diff --git a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
index f38bb445824..72d4cd72c2b 100644
--- a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
+++ b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
@@ -152,7 +152,7 @@ impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
                     | ty::Slice(_)
                     | ty::FnDef(_, _)
                     | ty::FnPtr(..)
-                    | ty::Dynamic(_, _, _)
+                    | ty::Dynamic(_, _)
                     | ty::Closure(..)
                     | ty::CoroutineClosure(..)
                     | ty::Coroutine(_, _)
@@ -196,7 +196,7 @@ impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
                     | ty::Ref(_, _, _)
                     | ty::FnDef(_, _)
                     | ty::FnPtr(..)
-                    | ty::Dynamic(_, _, _)
+                    | ty::Dynamic(_, _)
                     | ty::CoroutineWitness(..)
                     | ty::Never
                     | ty::UnsafeBinder(_)
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index 08316aaed3b..c1cd2788348 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -1884,7 +1884,7 @@ fn check_must_not_suspend_ty<'tcx>(
             }
             has_emitted
         }
-        ty::Dynamic(binder, _, _) => {
+        ty::Dynamic(binder, _) => {
             let mut has_emitted = false;
             for predicate in binder.iter() {
                 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
diff --git a/compiler/rustc_next_trait_solver/src/canonicalizer.rs b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
index a8f2b4e8db6..4b4ec4956eb 100644
--- a/compiler/rustc_next_trait_solver/src/canonicalizer.rs
+++ b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
@@ -390,7 +390,7 @@ impl<'a, D: SolverDelegate<Interner = I>, I: Interner> Canonicalizer<'a, D, I> {
             | ty::FnDef(_, _)
             | ty::FnPtr(..)
             | ty::UnsafeBinder(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs b/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs
index fb777496e31..7de7870bbb1 100644
--- a/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs
@@ -86,7 +86,7 @@ where
     ) -> Result<Candidate<I>, NoSolution> {
         Self::probe_and_match_goal_against_assumption(ecx, source, goal, assumption, |ecx| {
             let cx = ecx.cx();
-            let ty::Dynamic(bounds, _, _) = goal.predicate.self_ty().kind() else {
+            let ty::Dynamic(bounds, _) = goal.predicate.self_ty().kind() else {
                 panic!("expected object type in `probe_and_consider_object_bound_candidate`");
             };
             match structural_traits::predicates_for_object_candidate(
diff --git a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
index f6eab286ba7..c40739d12e6 100644
--- a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
@@ -383,7 +383,7 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_callable<I: Intern
         | ty::Slice(_)
         | ty::RawPtr(_, _)
         | ty::Ref(_, _, _)
-        | ty::Dynamic(_, _, _)
+        | ty::Dynamic(_, _)
         | ty::Coroutine(_, _)
         | ty::CoroutineWitness(..)
         | ty::Never
@@ -557,7 +557,7 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<I:
         | ty::Slice(_)
         | ty::RawPtr(_, _)
         | ty::Ref(_, _, _)
-        | ty::Dynamic(_, _, _)
+        | ty::Dynamic(_, _)
         | ty::Coroutine(_, _)
         | ty::CoroutineWitness(..)
         | ty::Never
@@ -706,7 +706,7 @@ pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
         | ty::Slice(_)
         | ty::RawPtr(_, _)
         | ty::Ref(_, _, _)
-        | ty::Dynamic(_, _, _)
+        | ty::Dynamic(_, _)
         | ty::Coroutine(_, _)
         | ty::CoroutineWitness(..)
         | ty::Never
diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
index 54b92ebac1d..653c59c5d42 100644
--- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
@@ -665,7 +665,7 @@ where
 
             ty::Str | ty::Slice(_) => Ty::new_usize(cx),
 
-            ty::Dynamic(_, _, ty::Dyn) => {
+            ty::Dynamic(_, _) => {
                 let dyn_metadata = cx.require_lang_item(SolverLangItem::DynMetadata);
                 cx.type_of(dyn_metadata)
                     .instantiate(cx, &[I::GenericArg::from(goal.predicate.self_ty())])
@@ -916,7 +916,7 @@ where
             | ty::Adt(_, _)
             | ty::Str
             | ty::Slice(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Tuple(_)
             | ty::Error(_) => self_ty.discriminant_ty(ecx.cx()),
 
diff --git a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
index a69e867289c..3974114e9b4 100644
--- a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
@@ -817,15 +817,13 @@ where
                 }
 
                 // Trait upcasting, or `dyn Trait + Auto + 'a` -> `dyn Trait + 'b`.
-                (
-                    ty::Dynamic(a_data, a_region, ty::Dyn),
-                    ty::Dynamic(b_data, b_region, ty::Dyn),
-                ) => ecx.consider_builtin_dyn_upcast_candidates(
-                    goal, a_data, a_region, b_data, b_region,
-                ),
+                (ty::Dynamic(a_data, a_region), ty::Dynamic(b_data, b_region)) => ecx
+                    .consider_builtin_dyn_upcast_candidates(
+                        goal, a_data, a_region, b_data, b_region,
+                    ),
 
                 // `T` -> `dyn Trait` unsizing.
-                (_, ty::Dynamic(b_region, b_data, ty::Dyn)) => result_to_single(
+                (_, ty::Dynamic(b_region, b_data)) => result_to_single(
                     ecx.consider_builtin_unsize_to_dyn_candidate(goal, b_region, b_data),
                 ),
 
diff --git a/compiler/rustc_passes/src/check_export.rs b/compiler/rustc_passes/src/check_export.rs
index 6eded3a9eb9..fee920221e1 100644
--- a/compiler/rustc_passes/src/check_export.rs
+++ b/compiler/rustc_passes/src/check_export.rs
@@ -295,7 +295,7 @@ impl<'tcx, 'a> TypeVisitor<TyCtxt<'tcx>> for ExportableItemsChecker<'tcx, 'a> {
             | ty::Ref(_, _, _)
             | ty::Param(_)
             | ty::Closure(_, _)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Coroutine(_, _)
             | ty::Foreign(_)
             | ty::Str
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index c9bf4fe4449..d9f8085083e 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -407,7 +407,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
             | ty::FnDef(_, _)
             | ty::FnPtr(..)
             | ty::Pat(_, _)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_public/src/ty.rs b/compiler/rustc_public/src/ty.rs
index bcc77ff849d..0afb94c18d7 100644
--- a/compiler/rustc_public/src/ty.rs
+++ b/compiler/rustc_public/src/ty.rs
@@ -333,7 +333,7 @@ impl TyKind {
 
     #[inline]
     pub fn is_trait(&self) -> bool {
-        matches!(self, TyKind::RigidTy(RigidTy::Dynamic(_, _, DynKind::Dyn)))
+        matches!(self, TyKind::RigidTy(RigidTy::Dynamic(_, _)))
     }
 
     #[inline]
@@ -472,7 +472,7 @@ impl TyKind {
     }
 
     pub fn trait_principal(&self) -> Option<Binder<ExistentialTraitRef>> {
-        if let TyKind::RigidTy(RigidTy::Dynamic(predicates, _, _)) = self {
+        if let TyKind::RigidTy(RigidTy::Dynamic(predicates, _)) = self {
             if let Some(Binder { value: ExistentialPredicate::Trait(trait_ref), bound_vars }) =
                 predicates.first()
             {
@@ -562,7 +562,7 @@ pub enum RigidTy {
     Closure(ClosureDef, GenericArgs),
     Coroutine(CoroutineDef, GenericArgs),
     CoroutineClosure(CoroutineClosureDef, GenericArgs),
-    Dynamic(Vec<Binder<ExistentialPredicate>>, Region, DynKind),
+    Dynamic(Vec<Binder<ExistentialPredicate>>, Region),
     Never,
     Tuple(Vec<Ty>),
     CoroutineWitness(CoroutineWitnessDef, GenericArgs),
@@ -1207,11 +1207,6 @@ pub enum BoundRegionKind {
 }
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize)]
-pub enum DynKind {
-    Dyn,
-}
-
-#[derive(Clone, Debug, Eq, PartialEq, Serialize)]
 pub enum ExistentialPredicate {
     Trait(ExistentialTraitRef),
     Projection(ExistentialProjection),
diff --git a/compiler/rustc_public/src/unstable/convert/internal.rs b/compiler/rustc_public/src/unstable/convert/internal.rs
index 66f767a98f5..dc9abd88614 100644
--- a/compiler/rustc_public/src/unstable/convert/internal.rs
+++ b/compiler/rustc_public/src/unstable/convert/internal.rs
@@ -14,7 +14,7 @@ use crate::mir::alloc::AllocId;
 use crate::mir::mono::{Instance, MonoItem, StaticDef};
 use crate::mir::{BinOp, Mutability, Place, ProjectionElem, RawPtrKind, Safety, UnOp};
 use crate::ty::{
-    Abi, AdtDef, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind, DynKind,
+    Abi, AdtDef, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind,
     ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FloatTy, FnSig,
     GenericArgKind, GenericArgs, IntTy, MirConst, Movability, Pattern, Region, RigidTy, Span,
     TermKind, TraitRef, Ty, TyConst, UintTy, VariantDef, VariantIdx,
@@ -188,10 +188,9 @@ impl RustcInternal for RigidTy {
                 def.0.internal(tables, tcx),
                 args.internal(tables, tcx),
             ),
-            RigidTy::Dynamic(predicate, region, dyn_kind) => rustc_ty::TyKind::Dynamic(
+            RigidTy::Dynamic(predicate, region) => rustc_ty::TyKind::Dynamic(
                 tcx.mk_poly_existential_predicates(&predicate.internal(tables, tcx)),
                 region.internal(tables, tcx),
-                dyn_kind.internal(tables, tcx),
             ),
             RigidTy::Tuple(tys) => {
                 rustc_ty::TyKind::Tuple(tcx.mk_type_list(&tys.internal(tables, tcx)))
@@ -460,20 +459,6 @@ impl RustcInternal for BoundVariableKind {
     }
 }
 
-impl RustcInternal for DynKind {
-    type T<'tcx> = rustc_ty::DynKind;
-
-    fn internal<'tcx>(
-        &self,
-        _tables: &mut Tables<'_, BridgeTys>,
-        _tcx: impl InternalCx<'tcx>,
-    ) -> Self::T<'tcx> {
-        match self {
-            DynKind::Dyn => rustc_ty::DynKind::Dyn,
-        }
-    }
-}
-
 impl RustcInternal for ExistentialPredicate {
     type T<'tcx> = rustc_ty::ExistentialPredicate<'tcx>;
 
diff --git a/compiler/rustc_public/src/unstable/convert/stable/ty.rs b/compiler/rustc_public/src/unstable/convert/stable/ty.rs
index 5131611eb02..7f14f878d37 100644
--- a/compiler/rustc_public/src/unstable/convert/stable/ty.rs
+++ b/compiler/rustc_public/src/unstable/convert/stable/ty.rs
@@ -48,16 +48,6 @@ impl<'tcx> Stable<'tcx> for ty::AliasTerm<'tcx> {
     }
 }
 
-impl<'tcx> Stable<'tcx> for ty::DynKind {
-    type T = crate::ty::DynKind;
-
-    fn stable(&self, _: &mut Tables<'_, BridgeTys>, _: &CompilerCtxt<'_, BridgeTys>) -> Self::T {
-        match self {
-            ty::Dyn => crate::ty::DynKind::Dyn,
-        }
-    }
-}
-
 impl<'tcx> Stable<'tcx> for ty::ExistentialPredicate<'tcx> {
     type T = crate::ty::ExistentialPredicate;
 
@@ -439,16 +429,13 @@ impl<'tcx> Stable<'tcx> for ty::TyKind<'tcx> {
             }
             // FIXME(unsafe_binders):
             ty::UnsafeBinder(_) => todo!(),
-            ty::Dynamic(existential_predicates, region, dyn_kind) => {
-                TyKind::RigidTy(RigidTy::Dynamic(
-                    existential_predicates
-                        .iter()
-                        .map(|existential_predicate| existential_predicate.stable(tables, cx))
-                        .collect(),
-                    region.stable(tables, cx),
-                    dyn_kind.stable(tables, cx),
-                ))
-            }
+            ty::Dynamic(existential_predicates, region) => TyKind::RigidTy(RigidTy::Dynamic(
+                existential_predicates
+                    .iter()
+                    .map(|existential_predicate| existential_predicate.stable(tables, cx))
+                    .collect(),
+                region.stable(tables, cx),
+            )),
             ty::Closure(def_id, generic_args) => TyKind::RigidTy(RigidTy::Closure(
                 tables.closure_def(*def_id),
                 generic_args.stable(tables, cx),
diff --git a/compiler/rustc_public/src/visitor.rs b/compiler/rustc_public/src/visitor.rs
index 87f1cc6ae69..acc33347696 100644
--- a/compiler/rustc_public/src/visitor.rs
+++ b/compiler/rustc_public/src/visitor.rs
@@ -171,7 +171,7 @@ impl Visitable for RigidTy {
             | RigidTy::CoroutineClosure(_, args)
             | RigidTy::FnDef(_, args) => args.visit(visitor),
             RigidTy::FnPtr(sig) => sig.visit(visitor),
-            RigidTy::Dynamic(pred, r, _) => {
+            RigidTy::Dynamic(pred, r) => {
                 pred.visit(visitor)?;
                 r.visit(visitor)
             }
diff --git a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
index f4a14b36ce5..ec7a4a81a71 100644
--- a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
+++ b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
@@ -626,12 +626,10 @@ pub(crate) fn encode_ty<'tcx>(
         }
 
         // Trait types
-        ty::Dynamic(predicates, region, kind) => {
+        ty::Dynamic(predicates, region) => {
             // u3dynI<element-type1[..element-typeN]>E, where <element-type> is <predicate>, as
             // vendor extended type.
-            let mut s = String::from(match kind {
-                ty::Dyn => "u3dynI",
-            });
+            let mut s = String::from("u3dynI");
             s.push_str(&encode_predicates(tcx, predicates, dict, options));
             s.push_str(&encode_region(*region, dict));
             s.push('E');
diff --git a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs
index 577a16a0d25..82a2a64f230 100644
--- a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs
+++ b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs
@@ -268,7 +268,7 @@ fn trait_object_ty<'tcx>(tcx: TyCtxt<'tcx>, poly_trait_ref: ty::PolyTraitRef<'tc
     let preds = tcx.mk_poly_existential_predicates_from_iter(
         iter::once(principal_pred).chain(assoc_preds.into_iter()),
     );
-    Ty::new_dynamic(tcx, preds, tcx.lifetimes.re_erased, ty::Dyn)
+    Ty::new_dynamic(tcx, preds, tcx.lifetimes.re_erased)
 }
 
 /// Transforms an instance for LLVM CFI and cross-language LLVM CFI support using Itanium C++ ABI
@@ -334,7 +334,7 @@ pub(crate) fn transform_instance<'tcx>(
             ty::List::empty(),
         ));
         let predicates = tcx.mk_poly_existential_predicates(&[ty::Binder::dummy(predicate)]);
-        let self_ty = Ty::new_dynamic(tcx, predicates, tcx.lifetimes.re_erased, ty::Dyn);
+        let self_ty = Ty::new_dynamic(tcx, predicates, tcx.lifetimes.re_erased);
         instance.args = tcx.mk_args_trait(self_ty, List::empty());
     } else if let ty::InstanceKind::Virtual(def_id, _) = instance.def {
         // Transform self into a trait object of the trait that defines the method for virtual
@@ -347,7 +347,7 @@ pub(crate) fn transform_instance<'tcx>(
             // drop_in_place won't have a defining trait, skip the upcast
             None => instance.args.type_at(0),
         };
-        let ty::Dynamic(preds, lifetime, kind) = upcast_ty.kind() else {
+        let ty::Dynamic(preds, lifetime) = upcast_ty.kind() else {
             bug!("Tried to remove autotraits from non-dynamic type {upcast_ty}");
         };
         let self_ty = if preds.principal().is_some() {
@@ -355,7 +355,7 @@ pub(crate) fn transform_instance<'tcx>(
                 tcx.mk_poly_existential_predicates_from_iter(preds.into_iter().filter(|pred| {
                     !matches!(pred.skip_binder(), ty::ExistentialPredicate::AutoTrait(..))
                 }));
-            Ty::new_dynamic(tcx, filtered_preds, *lifetime, *kind)
+            Ty::new_dynamic(tcx, filtered_preds, *lifetime)
         } else {
             // If there's no principal type, re-encode it as a unit, since we don't know anything
             // about it. This technically discards the knowledge that it was a type that was made
diff --git a/compiler/rustc_symbol_mangling/src/export.rs b/compiler/rustc_symbol_mangling/src/export.rs
index 76ac82cf95a..3896e06a627 100644
--- a/compiler/rustc_symbol_mangling/src/export.rs
+++ b/compiler/rustc_symbol_mangling/src/export.rs
@@ -110,7 +110,7 @@ impl<'tcx> AbiHashStable<'tcx> for Ty<'tcx> {
             | ty::RawPtr(_, _)
             | ty::FnDef(_, _)
             | ty::FnPtr(_, _)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(_, _)
             | ty::CoroutineClosure(_, _)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs
index 1605b4958ba..9fa7e2f1003 100644
--- a/compiler/rustc_symbol_mangling/src/v0.rs
+++ b/compiler/rustc_symbol_mangling/src/v0.rs
@@ -577,10 +577,8 @@ impl<'tcx> Printer<'tcx> for V0SymbolMangler<'tcx> {
             // FIXME(unsafe_binder):
             ty::UnsafeBinder(..) => todo!(),
 
-            ty::Dynamic(predicates, r, kind) => {
-                self.push(match kind {
-                    ty::Dyn => "D",
-                });
+            ty::Dynamic(predicates, r) => {
+                self.push("D");
                 self.print_dyn_existential(predicates)?;
                 r.print(self)?;
             }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs
index 3edc365c886..5b831584176 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs
@@ -399,7 +399,7 @@ pub struct TraitObjectVisitor(pub FxIndexSet<DefId>);
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for TraitObjectVisitor {
     fn visit_ty(&mut self, t: Ty<'tcx>) {
         match t.kind() {
-            ty::Dynamic(preds, re, _) if re.is_static() => {
+            ty::Dynamic(preds, re) if re.is_static() => {
                 if let Some(def_id) = preds.principal_def_id() {
                     self.0.insert(def_id);
                 }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
index f997842a607..b0b858aa270 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
@@ -292,7 +292,7 @@ impl<T> Trait<T> for X {
                             );
                         }
                     }
-                    (ty::Dynamic(t, _, ty::DynKind::Dyn), ty::Alias(ty::Opaque, alias))
+                    (ty::Dynamic(t, _), ty::Alias(ty::Opaque, alias))
                         if let Some(def_id) = t.principal_def_id()
                             && tcx
                                 .explicit_item_self_bounds(alias.def_id)
@@ -314,9 +314,7 @@ impl<T> Trait<T> for X {
                             values.found, values.expected,
                         ));
                     }
-                    (ty::Dynamic(t, _, ty::DynKind::Dyn), _)
-                        if let Some(def_id) = t.principal_def_id() =>
-                    {
+                    (ty::Dynamic(t, _), _) if let Some(def_id) = t.principal_def_id() => {
                         let mut has_matching_impl = false;
                         tcx.for_each_relevant_impl(def_id, values.found, |did| {
                             if DeepRejectCtxt::relate_rigid_infer(tcx)
@@ -335,9 +333,7 @@ impl<T> Trait<T> for X {
                             ));
                         }
                     }
-                    (_, ty::Dynamic(t, _, ty::DynKind::Dyn))
-                        if let Some(def_id) = t.principal_def_id() =>
-                    {
+                    (_, ty::Dynamic(t, _)) if let Some(def_id) = t.principal_def_id() => {
                         let mut has_matching_impl = false;
                         tcx.for_each_relevant_impl(def_id, values.expected, |did| {
                             if DeepRejectCtxt::relate_rigid_infer(tcx)
@@ -489,7 +485,7 @@ impl<T> Trait<T> for X {
                             && let Some(then) = blk.expr
                             && def.is_box()
                             && let boxed_ty = args.type_at(0)
-                            && let ty::Dynamic(t, _, _) = boxed_ty.kind()
+                            && let ty::Dynamic(t, _) = boxed_ty.kind()
                             && let Some(def_id) = t.principal_def_id()
                             && let mut impl_def_ids = vec![]
                             && let _ =
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs
index 518d4fe17e8..9a8ccea3aca 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs
@@ -430,7 +430,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 let mut alt_span = None;
                 if let Some(ty) = ty
                     && sub.is_static()
-                    && let ty::Dynamic(preds, _, ty::DynKind::Dyn) = ty.kind()
+                    && let ty::Dynamic(preds, _) = ty.kind()
                     && let Some(def_id) = preds.principal_def_id()
                 {
                     for (clause, span) in
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
index f794ff632c5..b3d1b8e3888 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
@@ -554,7 +554,7 @@ fn attempt_dyn_to_enum_suggestion(
             // defaults to assuming that things are *not* sized, whereas we want to
             // fall back to assuming that things may be sized.
             match impl_type.kind() {
-                ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::DynKind::Dyn) => {
+                ty::Str | ty::Slice(_) | ty::Dynamic(_, _) => {
                     return None;
                 }
                 _ => {}
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
index bb5c6469f34..00c123981e1 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
@@ -237,7 +237,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     }
                 }
             }
-            if let ty::Dynamic(traits, _, _) = self_ty.kind() {
+            if let ty::Dynamic(traits, _) = self_ty.kind() {
                 for t in traits.iter() {
                     if let ty::ExistentialPredicate::Trait(trait_ref) = t.skip_binder() {
                         self_types.push(self.tcx.def_path_str(trait_ref.def_id));
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index f2f840581cf..37e622102e7 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -1131,7 +1131,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         },
                     )
                 }
-                ty::Dynamic(data, _, ty::Dyn) => data.iter().find_map(|pred| {
+                ty::Dynamic(data, _) => data.iter().find_map(|pred| {
                     if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
                         && self.tcx.is_lang_item(proj.def_id, LangItem::FnOnceOutput)
                         // for existential projection, args are shifted over by 1
@@ -1520,7 +1520,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         let ty::Ref(_, object_ty, hir::Mutability::Not) = target_ty.kind() else {
             return;
         };
-        let ty::Dynamic(predicates, _, ty::Dyn) = object_ty.kind() else {
+        let ty::Dynamic(predicates, _) = object_ty.kind() else {
             return;
         };
         let self_ref_ty = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, self_ty);
@@ -1883,7 +1883,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         let ObligationCauseCode::SizedReturnType = obligation.cause.code() else {
             return false;
         };
-        let ty::Dynamic(_, _, ty::Dyn) = trait_pred.self_ty().skip_binder().kind() else {
+        let ty::Dynamic(_, _) = trait_pred.self_ty().skip_binder().kind() else {
             return false;
         };
 
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 62795c8a3a6..60f1fcb26c0 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -669,7 +669,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                 // These may potentially implement `FnPtr`
                 ty::Placeholder(..)
-                | ty::Dynamic(_, _, _)
+                | ty::Dynamic(_, _)
                 | ty::Alias(_, _)
                 | ty::Infer(_)
                 | ty::Param(..)
@@ -991,7 +991,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         match (source.kind(), target.kind()) {
             // Trait+Kx+'a -> Trait+Ky+'b (upcasts).
-            (&ty::Dynamic(a_data, a_region, ty::Dyn), &ty::Dynamic(b_data, b_region, ty::Dyn)) => {
+            (&ty::Dynamic(a_data, a_region), &ty::Dynamic(b_data, b_region)) => {
                 // Upcast coercions permit several things:
                 //
                 // 1. Dropping auto traits, e.g., `Foo + Send` to `Foo`
@@ -1054,7 +1054,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
 
             // `T` -> `Trait`
-            (_, &ty::Dynamic(_, _, ty::Dyn)) => {
+            (_, &ty::Dynamic(_, _)) => {
                 candidates.vec.push(BuiltinUnsizeCandidate);
             }
 
@@ -1327,7 +1327,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Pat(_, _)
             | ty::FnPtr(..)
             | ty::UnsafeBinder(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(..)
             | ty::CoroutineClosure(..)
             | ty::Coroutine(_, _)
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 488094b15ac..7ad65a1df8e 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -1023,10 +1023,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let a_ty = self.infcx.shallow_resolve(predicate.self_ty());
         let b_ty = self.infcx.shallow_resolve(predicate.trait_ref.args.type_at(1));
 
-        let ty::Dynamic(a_data, a_region, ty::Dyn) = *a_ty.kind() else {
+        let ty::Dynamic(a_data, a_region) = *a_ty.kind() else {
             bug!("expected `dyn` type in `confirm_trait_upcasting_unsize_candidate`")
         };
-        let ty::Dynamic(b_data, b_region, ty::Dyn) = *b_ty.kind() else {
+        let ty::Dynamic(b_data, b_region) = *b_ty.kind() else {
             bug!("expected `dyn` type in `confirm_trait_upcasting_unsize_candidate`")
         };
 
@@ -1062,10 +1062,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         debug!(?source, ?target, "confirm_builtin_unsize_candidate");
 
         Ok(match (source.kind(), target.kind()) {
-            // Trait+Kx+'a -> Trait+Ky+'b (auto traits and lifetime subtyping).
-            (&ty::Dynamic(data_a, r_a, dyn_a), &ty::Dynamic(data_b, r_b, dyn_b))
-                if dyn_a == dyn_b =>
-            {
+            // `dyn Trait + Kx + 'a` -> `dyn Trait + Ky + 'b` (auto traits and lifetime subtyping).
+            (&ty::Dynamic(data_a, r_a), &ty::Dynamic(data_b, r_b)) => {
                 // See `assemble_candidates_for_unsizing` for more info.
                 // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`.
                 let existential_predicates = if data_b.principal().is_some() {
@@ -1098,7 +1096,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             .map(ty::Binder::dummy),
                     )
                 };
-                let source_trait = Ty::new_dynamic(tcx, existential_predicates, r_b, dyn_a);
+                let source_trait = Ty::new_dynamic(tcx, existential_predicates, r_b);
 
                 // Require that the traits involved in this upcast are **equal**;
                 // only the **lifetime bound** is changed.
@@ -1122,7 +1120,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
 
             // `T` -> `dyn Trait`
-            (_, &ty::Dynamic(data, r, ty::Dyn)) => {
+            (_, &ty::Dynamic(data, r)) => {
                 let mut object_dids = data.auto_traits().chain(data.principal_def_id());
                 if let Some(did) = object_dids.find(|did| !tcx.is_dyn_compatible(*did)) {
                     return Err(SelectionError::TraitDynIncompatible(did));
diff --git a/compiler/rustc_trait_selection/src/traits/vtable.rs b/compiler/rustc_trait_selection/src/traits/vtable.rs
index 7e8a41457d4..584c8e2a27c 100644
--- a/compiler/rustc_trait_selection/src/traits/vtable.rs
+++ b/compiler/rustc_trait_selection/src/traits/vtable.rs
@@ -317,7 +317,7 @@ pub(crate) fn first_method_vtable_slot<'tcx>(tcx: TyCtxt<'tcx>, key: ty::TraitRe
         "vtable trait ref should be normalized"
     );
 
-    let ty::Dynamic(source, _, _) = *key.self_ty().kind() else {
+    let ty::Dynamic(source, _) = *key.self_ty().kind() else {
         bug!();
     };
     let source_principal = tcx.instantiate_bound_regions_with_erased(
@@ -384,13 +384,13 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
     let (source, target) = key;
 
     // If the target principal is `None`, we can just return `None`.
-    let ty::Dynamic(target_data, _, _) = *target.kind() else {
+    let ty::Dynamic(target_data, _) = *target.kind() else {
         bug!();
     };
     let target_principal = tcx.instantiate_bound_regions_with_erased(target_data.principal()?);
 
     // Given that we have a target principal, it is a bug for there not to be a source principal.
-    let ty::Dynamic(source_data, _, _) = *source.kind() else {
+    let ty::Dynamic(source_data, _) = *source.kind() else {
         bug!();
     };
     let source_principal = tcx.instantiate_bound_regions_with_erased(
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index adce9850b59..45cbb56b1c2 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -915,7 +915,7 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
                 // We recurse into the binder below.
             }
 
-            ty::Dynamic(data, r, _) => {
+            ty::Dynamic(data, r) => {
                 // WfObject
                 //
                 // Here, we defer WF checking due to higher-ranked
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 79f7e228e2a..643e3db8f83 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -476,7 +476,7 @@ fn layout_of_uncached<'tcx>(
         }
 
         // Odd unit types.
-        ty::FnDef(..) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => {
+        ty::FnDef(..) | ty::Dynamic(_, _) | ty::Foreign(..) => {
             let sized = matches!(ty.kind(), ty::FnDef(..));
             tcx.mk_layout(LayoutData::unit(cx, sized))
         }
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index a5987757dc3..18a9a7c22d9 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -40,7 +40,7 @@ fn sizedness_constraint_for_ty<'tcx>(
         | ty::CoroutineWitness(..)
         | ty::Never => None,
 
-        ty::Str | ty::Slice(..) | ty::Dynamic(_, _, ty::Dyn) => match sizedness {
+        ty::Str | ty::Slice(..) | ty::Dynamic(_, _) => match sizedness {
             // Never `Sized`
             SizedTraitKind::Sized => Some(ty),
             // Always `MetaSized`
@@ -366,7 +366,7 @@ fn impl_self_is_guaranteed_unsized<'tcx>(tcx: TyCtxt<'tcx>, impl_def_id: DefId)
     );
 
     match tail.kind() {
-        ty::Dynamic(_, _, ty::Dyn) | ty::Slice(_) | ty::Str => true,
+        ty::Dynamic(_, _) | ty::Slice(_) | ty::Str => true,
         ty::Bool
         | ty::Char
         | ty::Int(_)
diff --git a/compiler/rustc_type_ir/src/flags.rs b/compiler/rustc_type_ir/src/flags.rs
index 23b7f55fbbe..24704c5bb53 100644
--- a/compiler/rustc_type_ir/src/flags.rs
+++ b/compiler/rustc_type_ir/src/flags.rs
@@ -288,7 +288,7 @@ impl<I: Interner> FlagComputation<I> {
                 self.add_alias_ty(data);
             }
 
-            ty::Dynamic(obj, r, _) => {
+            ty::Dynamic(obj, r) => {
                 for predicate in obj.iter() {
                     self.bound_computation(predicate, |computation, predicate| match predicate {
                         ty::ExistentialPredicate::Trait(tr) => {
diff --git a/compiler/rustc_type_ir/src/inherent.rs b/compiler/rustc_type_ir/src/inherent.rs
index ecfc05a6e20..b5b552dbaec 100644
--- a/compiler/rustc_type_ir/src/inherent.rs
+++ b/compiler/rustc_type_ir/src/inherent.rs
@@ -76,12 +76,7 @@ pub trait Ty<I: Interner<Ty = Self>>:
 
     fn new_foreign(interner: I, def_id: I::ForeignId) -> Self;
 
-    fn new_dynamic(
-        interner: I,
-        preds: I::BoundExistentialPredicates,
-        region: I::Region,
-        kind: ty::DynKind,
-    ) -> Self;
+    fn new_dynamic(interner: I, preds: I::BoundExistentialPredicates, region: I::Region) -> Self;
 
     fn new_coroutine(interner: I, def_id: I::CoroutineId, args: I::GenericArgs) -> Self;
 
@@ -167,7 +162,7 @@ pub trait Ty<I: Interner<Ty = Self>>:
 
     fn is_guaranteed_unsized_raw(self) -> bool {
         match self.kind() {
-            ty::Dynamic(_, _, ty::Dyn) | ty::Slice(_) | ty::Str => true,
+            ty::Dynamic(_, _) | ty::Slice(_) | ty::Str => true,
             ty::Bool
             | ty::Char
             | ty::Int(_)
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index 50b588029ae..61e0b67b163 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -57,7 +57,6 @@ mod upcast;
 mod visit;
 
 pub use AliasTyKind::*;
-pub use DynKind::*;
 pub use InferTy::*;
 pub use RegionKind::*;
 pub use TyKind::*;
diff --git a/compiler/rustc_type_ir/src/outlives.rs b/compiler/rustc_type_ir/src/outlives.rs
index b09a378d341..c7dccea6adc 100644
--- a/compiler/rustc_type_ir/src/outlives.rs
+++ b/compiler/rustc_type_ir/src/outlives.rs
@@ -203,7 +203,7 @@ impl<I: Interner> TypeVisitor<I> for OutlivesCollector<'_, I> {
             | ty::Ref(_, _, _)
             | ty::FnPtr(..)
             | ty::UnsafeBinder(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Tuple(_) => {
                 ty.super_visit_with(self);
             }
diff --git a/compiler/rustc_type_ir/src/relate.rs b/compiler/rustc_type_ir/src/relate.rs
index 690a5f65e08..09add529286 100644
--- a/compiler/rustc_type_ir/src/relate.rs
+++ b/compiler/rustc_type_ir/src/relate.rs
@@ -412,16 +412,11 @@ pub fn structurally_relate_tys<I: Interner, R: TypeRelation<I>>(
 
         (ty::Foreign(a_id), ty::Foreign(b_id)) if a_id == b_id => Ok(Ty::new_foreign(cx, a_id)),
 
-        (ty::Dynamic(a_obj, a_region, a_repr), ty::Dynamic(b_obj, b_region, b_repr))
-            if a_repr == b_repr =>
-        {
-            Ok(Ty::new_dynamic(
-                cx,
-                relation.relate(a_obj, b_obj)?,
-                relation.relate(a_region, b_region)?,
-                a_repr,
-            ))
-        }
+        (ty::Dynamic(a_obj, a_region), ty::Dynamic(b_obj, b_region)) => Ok(Ty::new_dynamic(
+            cx,
+            relation.relate(a_obj, b_obj)?,
+            relation.relate(a_region, b_region)?,
+        )),
 
         (ty::Coroutine(a_id, a_args), ty::Coroutine(b_id, b_args)) if a_id == b_id => {
             // All Coroutine types with the same id represent
diff --git a/compiler/rustc_type_ir/src/ty_kind.rs b/compiler/rustc_type_ir/src/ty_kind.rs
index 225d85f79c3..dda59283677 100644
--- a/compiler/rustc_type_ir/src/ty_kind.rs
+++ b/compiler/rustc_type_ir/src/ty_kind.rs
@@ -19,20 +19,6 @@ use crate::{self as ty, DebruijnIndex, FloatTy, IntTy, Interner, UintTy};
 
 mod closure;
 
-/// Specifies how a trait object is represented.
-///
-/// This used to have a variant `DynStar`, but that variant has been removed,
-/// and it's likely this whole enum will be removed soon.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[cfg_attr(
-    feature = "nightly",
-    derive(Encodable_NoContext, Decodable_NoContext, HashStable_NoContext)
-)]
-pub enum DynKind {
-    /// An unsized `dyn Trait` object
-    Dyn,
-}
-
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 #[cfg_attr(
     feature = "nightly",
@@ -165,7 +151,7 @@ pub enum TyKind<I: Interner> {
     UnsafeBinder(UnsafeBinderInner<I>),
 
     /// A trait object. Written as `dyn for<'b> Trait<'b, Assoc = u32> + Send + 'a`.
-    Dynamic(I::BoundExistentialPredicates, I::Region, DynKind),
+    Dynamic(I::BoundExistentialPredicates, I::Region),
 
     /// The anonymous type of a closure. Used to represent the type of `|a| a`.
     ///
@@ -314,7 +300,7 @@ impl<I: Interner> TyKind<I> {
             | ty::FnDef(_, _)
             | ty::FnPtr(..)
             | ty::UnsafeBinder(_)
-            | ty::Dynamic(_, _, _)
+            | ty::Dynamic(_, _)
             | ty::Closure(_, _)
             | ty::CoroutineClosure(_, _)
             | ty::Coroutine(_, _)
@@ -367,9 +353,7 @@ impl<I: Interner> fmt::Debug for TyKind<I> {
             FnPtr(sig_tys, hdr) => write!(f, "{:?}", sig_tys.with(*hdr)),
             // FIXME(unsafe_binder): print this like `unsafe<'a> T<'a>`.
             UnsafeBinder(binder) => write!(f, "{:?}", binder),
-            Dynamic(p, r, repr) => match repr {
-                DynKind::Dyn => write!(f, "dyn {p:?} + {r:?}"),
-            },
+            Dynamic(p, r) => write!(f, "dyn {p:?} + {r:?}"),
             Closure(d, s) => f.debug_tuple("Closure").field(d).field(&s).finish(),
             CoroutineClosure(d, s) => f.debug_tuple("CoroutineClosure").field(d).field(&s).finish(),
             Coroutine(d, s) => f.debug_tuple("Coroutine").field(d).field(&s).finish(),
diff --git a/compiler/rustc_type_ir/src/walk.rs b/compiler/rustc_type_ir/src/walk.rs
index 9912fad1756..6d51817a7bf 100644
--- a/compiler/rustc_type_ir/src/walk.rs
+++ b/compiler/rustc_type_ir/src/walk.rs
@@ -109,7 +109,7 @@ fn push_inner<I: Interner>(stack: &mut TypeWalkerStack<I>, parent: I::GenericArg
             ty::Alias(_, data) => {
                 stack.extend(data.args.iter().rev());
             }
-            ty::Dynamic(obj, lt, _) => {
+            ty::Dynamic(obj, lt) => {
                 stack.push(lt.into());
                 stack.extend(
                     obj.iter()