diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index bb65c3c81d952..a7ac728c59b02 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -2991,25 +2991,10 @@ fn add_lld_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         return;
     }
 
-    let self_contained_linker = sess.opts.cg.link_self_contained.linker();
-
-    // FIXME: some targets default to using `lld`, but users can only override the linker on the CLI
-    // and cannot yet select the precise linker flavor to opt out of that. See for example issue
-    // #113597 for the `thumbv6m-none-eabi` target: a driver is used, and its default linker
-    // conflicts with the target's flavor, causing unexpected arguments being passed.
-    //
-    // Until the new `LinkerFlavor`-like CLI options are stabilized, we only adopt MCP510's behavior
-    // if its dedicated unstable CLI flags are used, to keep the current sub-optimal stable
-    // behavior.
-    let using_mcp510 =
-        self_contained_linker || sess.opts.cg.linker_flavor.is_some_and(|f| f.is_unstable());
-    if !using_mcp510 && !unstable_use_lld {
-        return;
-    }
-
     // 1. Implement the "self-contained" part of this feature by adding rustc distribution
     //    directories to the tool's search path.
-    if self_contained_linker || unstable_use_lld {
+    let self_contained_linker = sess.opts.cg.link_self_contained.linker() || unstable_use_lld;
+    if self_contained_linker {
         for path in sess.get_tools_search_paths(false) {
             cmd.arg({
                 let mut arg = OsString::from("-B");
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 8a5099804ed26..46e8cf81bc1f7 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -8,7 +8,7 @@ use rustc_attr as attr;
 use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::{ItemKind, Node, PathSegment};
 use rustc_infer::infer::opaque_types::ConstrainOpaqueTypeRegionVisitor;
@@ -1443,12 +1443,12 @@ pub(super) fn check_type_params_are_used<'tcx>(
     }
 }
 
-pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let module = tcx.hir_module_items(module_def_id);
     for id in module.items() {
         check_item_type(tcx, id);
     }
-    if module_def_id == CRATE_DEF_ID {
+    if module_def_id == LocalModDefId::CRATE_DEF_ID {
         super::entry::check_for_entry_fn(tcx);
     }
 }
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 16d4d099c7e5e..f5beefc47f374 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -5,7 +5,7 @@ use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
 use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::ItemKind;
 use rustc_infer::infer::outlives::env::{OutlivesEnvironment, RegionBoundPairs};
@@ -1854,7 +1854,7 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
     }
 }
 
-fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalDefId) {
+fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalModDefId) {
     let items = tcx.hir_module_items(module);
     items.par_items(|item| tcx.ensure().check_well_formed(item.owner_id));
     items.par_impl_items(|item| tcx.ensure().check_well_formed(item.owner_id));
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 02a5d28b1e233..7b9f61d7ab213 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -22,7 +22,7 @@ use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{GenericParamKind, Node};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
@@ -48,7 +48,7 @@ mod type_of;
 ///////////////////////////////////////////////////////////////////////////
 // Main entry point
 
-fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut CollectItemTypesVisitor { tcx });
 }
 
diff --git a/compiler/rustc_hir_analysis/src/impl_wf_check.rs b/compiler/rustc_hir_analysis/src/impl_wf_check.rs
index 4f705eaf10aac..788121f7a304f 100644
--- a/compiler/rustc_hir_analysis/src/impl_wf_check.rs
+++ b/compiler/rustc_hir_analysis/src/impl_wf_check.rs
@@ -14,7 +14,7 @@ use min_specialization::check_min_specialization;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_span::{Span, Symbol};
@@ -51,7 +51,7 @@ mod min_specialization;
 /// impl<'a> Trait<Foo> for Bar { type X = &'a i32; }
 /// //   ^ 'a is unused and appears in assoc type, error
 /// ```
-fn check_mod_impl_wf(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_impl_wf(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let min_specialization = tcx.features().min_specialization;
     let module = tcx.hir_module_items(module_def_id);
     for id in module.items() {
diff --git a/compiler/rustc_lint/src/late.rs b/compiler/rustc_lint/src/late.rs
index 3331dbad4a90e..73af51d9e9061 100644
--- a/compiler/rustc_lint/src/late.rs
+++ b/compiler/rustc_lint/src/late.rs
@@ -19,7 +19,7 @@ use rustc_ast as ast;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::join;
 use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit as hir_visit;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
@@ -338,7 +338,7 @@ crate::late_lint_methods!(impl_late_lint_pass, []);
 
 pub fn late_lint_mod<'tcx, T: LateLintPass<'tcx> + 'tcx>(
     tcx: TyCtxt<'tcx>,
-    module_def_id: LocalDefId,
+    module_def_id: LocalModDefId,
     builtin_lints: T,
 ) {
     let context = LateContext {
@@ -369,7 +369,7 @@ pub fn late_lint_mod<'tcx, T: LateLintPass<'tcx> + 'tcx>(
 
 fn late_lint_mod_inner<'tcx, T: LateLintPass<'tcx>>(
     tcx: TyCtxt<'tcx>,
-    module_def_id: LocalDefId,
+    module_def_id: LocalModDefId,
     context: LateContext<'tcx>,
     pass: T,
 ) {
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 42378951af36a..585b10e79e484 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -90,7 +90,7 @@ use rustc_ast as ast;
 use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage};
 use rustc_fluent_macro::fluent_messages;
 use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint::builtin::{
@@ -145,7 +145,7 @@ pub fn provide(providers: &mut Providers) {
     *providers = Providers { lint_mod, ..*providers };
 }
 
-fn lint_mod(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn lint_mod(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
 }
 
diff --git a/compiler/rustc_middle/src/dep_graph/dep_node.rs b/compiler/rustc_middle/src/dep_graph/dep_node.rs
index 06251bccc9856..04c09d334001b 100644
--- a/compiler/rustc_middle/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_middle/src/dep_graph/dep_node.rs
@@ -60,7 +60,7 @@ use crate::mir::mono::MonoItem;
 use crate::ty::TyCtxt;
 
 use rustc_data_structures::fingerprint::Fingerprint;
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalModDefId, ModDefId, LOCAL_CRATE};
 use rustc_hir::definitions::DefPathHash;
 use rustc_hir::{HirId, ItemLocalId, OwnerId};
 use rustc_query_system::dep_graph::FingerprintStyle;
@@ -387,3 +387,53 @@ impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for HirId {
         }
     }
 }
+
+macro_rules! impl_for_typed_def_id {
+    ($Name:ident, $LocalName:ident) => {
+        impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for $Name {
+            #[inline(always)]
+            fn fingerprint_style() -> FingerprintStyle {
+                FingerprintStyle::DefPathHash
+            }
+
+            #[inline(always)]
+            fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint {
+                self.to_def_id().to_fingerprint(tcx)
+            }
+
+            #[inline(always)]
+            fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
+                self.to_def_id().to_debug_str(tcx)
+            }
+
+            #[inline(always)]
+            fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
+                DefId::recover(tcx, dep_node).map($Name::new_unchecked)
+            }
+        }
+
+        impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for $LocalName {
+            #[inline(always)]
+            fn fingerprint_style() -> FingerprintStyle {
+                FingerprintStyle::DefPathHash
+            }
+
+            #[inline(always)]
+            fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint {
+                self.to_def_id().to_fingerprint(tcx)
+            }
+
+            #[inline(always)]
+            fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
+                self.to_def_id().to_debug_str(tcx)
+            }
+
+            #[inline(always)]
+            fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
+                LocalDefId::recover(tcx, dep_node).map($LocalName::new_unchecked)
+            }
+        }
+    };
+}
+
+impl_for_typed_def_id! { ModDefId, LocalModDefId }
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 224f897492bbe..467962b39bb1b 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -8,7 +8,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::{par_for_each_in, DynSend, DynSync};
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, DefPathData, DefPathHash};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::*;
@@ -148,7 +148,7 @@ impl<'hir> Map<'hir> {
     }
 
     #[inline]
-    pub fn module_items(self, module: LocalDefId) -> impl Iterator<Item = ItemId> + 'hir {
+    pub fn module_items(self, module: LocalModDefId) -> impl Iterator<Item = ItemId> + 'hir {
         self.tcx.hir_module_items(module).items()
     }
 
@@ -169,8 +169,8 @@ impl<'hir> Map<'hir> {
     }
 
     #[inline]
-    pub fn local_def_id_to_hir_id(self, def_id: LocalDefId) -> HirId {
-        self.tcx.local_def_id_to_hir_id(def_id)
+    pub fn local_def_id_to_hir_id(self, def_id: impl Into<LocalDefId>) -> HirId {
+        self.tcx.local_def_id_to_hir_id(def_id.into())
     }
 
     /// Do not call this function directly. The query should be called.
@@ -529,8 +529,8 @@ impl<'hir> Map<'hir> {
         self.krate_attrs().iter().any(|attr| attr.has_name(sym::rustc_coherence_is_core))
     }
 
-    pub fn get_module(self, module: LocalDefId) -> (&'hir Mod<'hir>, Span, HirId) {
-        let hir_id = HirId::make_owner(module);
+    pub fn get_module(self, module: LocalModDefId) -> (&'hir Mod<'hir>, Span, HirId) {
+        let hir_id = HirId::make_owner(module.to_local_def_id());
         match self.tcx.hir_owner(hir_id.owner).map(|o| o.node) {
             Some(OwnerNode::Item(&Item { span, kind: ItemKind::Mod(ref m), .. })) => {
                 (m, span, hir_id)
@@ -542,7 +542,7 @@ impl<'hir> Map<'hir> {
 
     /// Walks the contents of the local crate. See also `visit_all_item_likes_in_crate`.
     pub fn walk_toplevel_module(self, visitor: &mut impl Visitor<'hir>) {
-        let (top_mod, span, hir_id) = self.get_module(CRATE_DEF_ID);
+        let (top_mod, span, hir_id) = self.get_module(LocalModDefId::CRATE_DEF_ID);
         visitor.visit_mod(top_mod, span, hir_id);
     }
 
@@ -595,7 +595,7 @@ impl<'hir> Map<'hir> {
 
     /// This method is the equivalent of `visit_all_item_likes_in_crate` but restricted to
     /// item-likes in a single module.
-    pub fn visit_item_likes_in_module<V>(self, module: LocalDefId, visitor: &mut V)
+    pub fn visit_item_likes_in_module<V>(self, module: LocalModDefId, visitor: &mut V)
     where
         V: Visitor<'hir>,
     {
@@ -618,17 +618,19 @@ impl<'hir> Map<'hir> {
         }
     }
 
-    pub fn for_each_module(self, mut f: impl FnMut(LocalDefId)) {
+    pub fn for_each_module(self, mut f: impl FnMut(LocalModDefId)) {
         let crate_items = self.tcx.hir_crate_items(());
         for module in crate_items.submodules.iter() {
-            f(module.def_id)
+            f(LocalModDefId::new_unchecked(module.def_id))
         }
     }
 
     #[inline]
-    pub fn par_for_each_module(self, f: impl Fn(LocalDefId) + DynSend + DynSync) {
+    pub fn par_for_each_module(self, f: impl Fn(LocalModDefId) + DynSend + DynSync) {
         let crate_items = self.tcx.hir_crate_items(());
-        par_for_each_in(&crate_items.submodules[..], |module| f(module.def_id))
+        par_for_each_in(&crate_items.submodules[..], |module| {
+            f(LocalModDefId::new_unchecked(module.def_id))
+        })
     }
 
     /// Returns an iterator for the nodes in the ancestor tree of the `current_id`
@@ -1324,7 +1326,7 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
     }
 }
 
-pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalDefId) -> ModuleItems {
+pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> ModuleItems {
     let mut collector = ItemCollector::new(tcx, false);
 
     let (hir_mod, span, hir_id) = tcx.hir().get_module(module_id);
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index 06b25556c82a4..e8fd469e1fb8f 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -11,7 +11,7 @@ use crate::ty::{EarlyBinder, ImplSubject, TyCtxt};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::{par_for_each_in, DynSend, DynSync};
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::*;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_span::{ExpnId, DUMMY_SP};
@@ -101,22 +101,22 @@ impl<'tcx> TyCtxt<'tcx> {
         map::Map { tcx: self }
     }
 
-    pub fn parent_module(self, id: HirId) -> LocalDefId {
+    pub fn parent_module(self, id: HirId) -> LocalModDefId {
         if !id.is_owner() && self.def_kind(id.owner) == DefKind::Mod {
-            id.owner.def_id
+            LocalModDefId::new_unchecked(id.owner.def_id)
         } else {
             self.parent_module_from_def_id(id.owner.def_id)
         }
     }
 
-    pub fn parent_module_from_def_id(self, mut id: LocalDefId) -> LocalDefId {
+    pub fn parent_module_from_def_id(self, mut id: LocalDefId) -> LocalModDefId {
         while let Some(parent) = self.opt_local_parent(id) {
             id = parent;
             if self.def_kind(id) == DefKind::Mod {
                 break;
             }
         }
-        id
+        LocalModDefId::new_unchecked(id)
     }
 
     pub fn impl_subject(self, def_id: DefId) -> EarlyBinder<ImplSubject<'tcx>> {
diff --git a/compiler/rustc_middle/src/query/erase.rs b/compiler/rustc_middle/src/query/erase.rs
index 2c481745d987a..348f79ed6a800 100644
--- a/compiler/rustc_middle/src/query/erase.rs
+++ b/compiler/rustc_middle/src/query/erase.rs
@@ -235,6 +235,7 @@ trivial! {
     rustc_hir::def_id::DefId,
     rustc_hir::def_id::DefIndex,
     rustc_hir::def_id::LocalDefId,
+    rustc_hir::def_id::LocalModDefId,
     rustc_hir::def::DefKind,
     rustc_hir::Defaultness,
     rustc_hir::definitions::DefKey,
diff --git a/compiler/rustc_middle/src/query/keys.rs b/compiler/rustc_middle/src/query/keys.rs
index a8aec3096d5de..01bdc4c9904e5 100644
--- a/compiler/rustc_middle/src/query/keys.rs
+++ b/compiler/rustc_middle/src/query/keys.rs
@@ -8,7 +8,7 @@ use crate::ty::fast_reject::SimplifiedType;
 use crate::ty::layout::{TyAndLayout, ValidityRequirement};
 use crate::ty::{self, Ty, TyCtxt};
 use crate::ty::{GenericArg, GenericArgsRef};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalModDefId, ModDefId, LOCAL_CRATE};
 use rustc_hir::hir_id::{HirId, OwnerId};
 use rustc_query_system::query::{DefaultCacheSelector, SingleCacheSelector, VecCacheSelector};
 use rustc_span::symbol::{Ident, Symbol};
@@ -175,6 +175,41 @@ impl AsLocalKey for DefId {
     }
 }
 
+impl Key for LocalModDefId {
+    type CacheSelector = DefaultCacheSelector<Self>;
+
+    fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
+        tcx.def_span(*self)
+    }
+
+    #[inline(always)]
+    fn key_as_def_id(&self) -> Option<DefId> {
+        Some(self.to_def_id())
+    }
+}
+
+impl Key for ModDefId {
+    type CacheSelector = DefaultCacheSelector<Self>;
+
+    fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
+        tcx.def_span(*self)
+    }
+
+    #[inline(always)]
+    fn key_as_def_id(&self) -> Option<DefId> {
+        Some(self.to_def_id())
+    }
+}
+
+impl AsLocalKey for ModDefId {
+    type LocalKey = LocalModDefId;
+
+    #[inline(always)]
+    fn as_local_key(&self) -> Option<Self::LocalKey> {
+        self.as_local()
+    }
+}
+
 impl Key for SimplifiedType {
     type CacheSelector = DefaultCacheSelector<Self>;
 
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 5af77c6c4cb7c..e289ddab12022 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -67,7 +67,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, DocLinkResMap};
 use rustc_hir::def_id::{
-    CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId, LocalDefIdMap, LocalDefIdSet,
+    CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId, LocalDefIdMap, LocalDefIdSet, LocalModDefId,
 };
 use rustc_hir::lang_items::{LangItem, LanguageItems};
 use rustc_hir::{Crate, ItemLocalId, TraitCandidate};
@@ -167,7 +167,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by `tcx.hir().visit_item_likes_in_module`.
     /// Avoid calling this query directly.
-    query hir_module_items(key: LocalDefId) -> &'tcx rustc_middle::hir::ModuleItems {
+    query hir_module_items(key: LocalModDefId) -> &'tcx rustc_middle::hir::ModuleItems {
         arena_cache
         desc { |tcx| "getting HIR module items in `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { true }
@@ -896,7 +896,7 @@ rustc_queries! {
     }
 
     /// Performs lint checking for the module.
-    query lint_mod(key: LocalDefId) -> () {
+    query lint_mod(key: LocalModDefId) -> () {
         desc { |tcx| "linting {}", describe_as_module(key, tcx) }
     }
 
@@ -905,35 +905,35 @@ rustc_queries! {
     }
 
     /// Checks the attributes in the module.
-    query check_mod_attrs(key: LocalDefId) -> () {
+    query check_mod_attrs(key: LocalModDefId) -> () {
         desc { |tcx| "checking attributes in {}", describe_as_module(key, tcx) }
     }
 
     /// Checks for uses of unstable APIs in the module.
-    query check_mod_unstable_api_usage(key: LocalDefId) -> () {
+    query check_mod_unstable_api_usage(key: LocalModDefId) -> () {
         desc { |tcx| "checking for unstable API usage in {}", describe_as_module(key, tcx) }
     }
 
     /// Checks the const bodies in the module for illegal operations (e.g. `if` or `loop`).
-    query check_mod_const_bodies(key: LocalDefId) -> () {
+    query check_mod_const_bodies(key: LocalModDefId) -> () {
         desc { |tcx| "checking consts in {}", describe_as_module(key, tcx) }
     }
 
     /// Checks the loops in the module.
-    query check_mod_loops(key: LocalDefId) -> () {
+    query check_mod_loops(key: LocalModDefId) -> () {
         desc { |tcx| "checking loops in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_naked_functions(key: LocalDefId) -> () {
+    query check_mod_naked_functions(key: LocalModDefId) -> () {
         desc { |tcx| "checking naked functions in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_item_types(key: LocalDefId) -> () {
+    query check_mod_item_types(key: LocalModDefId) -> () {
         desc { |tcx| "checking item types in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_privacy(key: LocalDefId) -> () {
-        desc { |tcx| "checking privacy in {}", describe_as_module(key, tcx) }
+    query check_mod_privacy(key: LocalModDefId) -> () {
+        desc { |tcx| "checking privacy in {}", describe_as_module(key.to_local_def_id(), tcx) }
     }
 
     query check_liveness(key: LocalDefId) {
@@ -952,19 +952,19 @@ rustc_queries! {
         desc { "finding live symbols in crate" }
     }
 
-    query check_mod_deathness(key: LocalDefId) -> () {
+    query check_mod_deathness(key: LocalModDefId) -> () {
         desc { |tcx| "checking deathness of variables in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_impl_wf(key: LocalDefId) -> () {
+    query check_mod_impl_wf(key: LocalModDefId) -> () {
         desc { |tcx| "checking that impls are well-formed in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_type_wf(key: LocalDefId) -> () {
+    query check_mod_type_wf(key: LocalModDefId) -> () {
         desc { |tcx| "checking that types are well-formed in {}", describe_as_module(key, tcx) }
     }
 
-    query collect_mod_item_types(key: LocalDefId) -> () {
+    query collect_mod_item_types(key: LocalModDefId) -> () {
         desc { |tcx| "collecting item types in {}", describe_as_module(key, tcx) }
     }
 
diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs
index 97edfc2fca27d..a1aac2846210d 100644
--- a/compiler/rustc_middle/src/query/plumbing.rs
+++ b/compiler/rustc_middle/src/query/plumbing.rs
@@ -545,6 +545,7 @@ macro_rules! define_feedable {
 
 mod sealed {
     use super::{DefId, LocalDefId, OwnerId};
+    use rustc_hir::def_id::{LocalModDefId, ModDefId};
 
     /// An analogue of the `Into` trait that's intended only for query parameters.
     ///
@@ -588,6 +589,27 @@ mod sealed {
             self.to_def_id()
         }
     }
+
+    impl IntoQueryParam<DefId> for ModDefId {
+        #[inline(always)]
+        fn into_query_param(self) -> DefId {
+            self.to_def_id()
+        }
+    }
+
+    impl IntoQueryParam<DefId> for LocalModDefId {
+        #[inline(always)]
+        fn into_query_param(self) -> DefId {
+            self.to_def_id()
+        }
+    }
+
+    impl IntoQueryParam<LocalDefId> for LocalModDefId {
+        #[inline(always)]
+        fn into_query_param(self) -> LocalDefId {
+            self.into()
+        }
+    }
 }
 
 pub use sealed::IntoQueryParam;
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 377dd82a00e44..1274f427e4f7d 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -355,8 +355,8 @@ impl TyCtxt<'_> {
 
     #[inline]
     #[track_caller]
-    pub fn local_parent(self, id: LocalDefId) -> LocalDefId {
-        self.parent(id.to_def_id()).expect_local()
+    pub fn local_parent(self, id: impl Into<LocalDefId>) -> LocalDefId {
+        self.parent(id.into().to_def_id()).expect_local()
     }
 
     pub fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
diff --git a/compiler/rustc_middle/src/ty/print/mod.rs b/compiler/rustc_middle/src/ty/print/mod.rs
index 83a75d0c6b987..05871d0bc39d1 100644
--- a/compiler/rustc_middle/src/ty/print/mod.rs
+++ b/compiler/rustc_middle/src/ty/print/mod.rs
@@ -329,7 +329,8 @@ impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::Const<'tcx> {
 }
 
 // This is only used by query descriptions
-pub fn describe_as_module(def_id: LocalDefId, tcx: TyCtxt<'_>) -> String {
+pub fn describe_as_module(def_id: impl Into<LocalDefId>, tcx: TyCtxt<'_>) -> String {
+    let def_id = def_id.into();
     if def_id.is_top_level_module() {
         "top-level module".to_string()
     } else {
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index bb6513363c93f..ac0c88468faa5 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::sso::SsoHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::{self, CtorKind, DefKind, Namespace};
-use rustc_hir::def_id::{DefId, DefIdSet, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, DefIdSet, ModDefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPathData, DefPathDataName, DisambiguatedDefPathData};
 use rustc_hir::LangItem;
 use rustc_session::config::TrimmedDefPaths;
@@ -326,7 +326,8 @@ pub trait PrettyPrinter<'tcx>:
             {
                 this
                     .tcx()
-                    .module_children(visible_parent)
+                    // FIXME(typed_def_id): Further propagate ModDefId
+                    .module_children(ModDefId::new_unchecked(*visible_parent))
                     .iter()
                     .filter(|child| child.res.opt_def_id() == Some(def_id))
                     .find(|child| child.vis.is_public() && child.ident.name != kw::Underscore)
@@ -551,7 +552,8 @@ pub trait PrettyPrinter<'tcx>:
                 // that's public and whose identifier isn't `_`.
                 let reexport = self
                     .tcx()
-                    .module_children(visible_parent)
+                    // FIXME(typed_def_id): Further propagate ModDefId
+                    .module_children(ModDefId::new_unchecked(visible_parent))
                     .iter()
                     .filter(|child| child.res.opt_def_id() == Some(def_id))
                     .find(|child| child.vis.is_public() && child.ident.name != kw::Underscore)
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 4f9b362e23796..197b335bdec9b 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -10,7 +10,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, IntoDiagnosticArg, MultiSpan};
 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
 use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::LocalModDefId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{
     self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
@@ -2465,10 +2465,10 @@ fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>)
     }
 }
 
-fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let check_attr_visitor = &mut CheckAttrVisitor { tcx, abort: Cell::new(false) };
     tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
-    if module_def_id.is_top_level_module() {
+    if module_def_id.to_local_def_id().is_top_level_module() {
         check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
         check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
     }
diff --git a/compiler/rustc_passes/src/check_const.rs b/compiler/rustc_passes/src/check_const.rs
index e70817d7b7c55..495eb615ed889 100644
--- a/compiler/rustc_passes/src/check_const.rs
+++ b/compiler/rustc_passes/src/check_const.rs
@@ -9,7 +9,7 @@
 
 use rustc_attr as attr;
 use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::query::Providers;
@@ -55,7 +55,7 @@ impl NonConstExpr {
     }
 }
 
-fn check_mod_const_bodies(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_const_bodies(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let mut vis = CheckConstVisitor::new(tcx);
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut vis);
 }
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 2936c8fac7d91..d1c3bcf3839d5 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -8,7 +8,7 @@ use rustc_data_structures::unord::UnordSet;
 use rustc_errors::MultiSpan;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Res};
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
@@ -944,7 +944,7 @@ impl<'tcx> DeadVisitor<'tcx> {
     }
 }
 
-fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalDefId) {
+fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
     let (live_symbols, ignored_derived_traits) = tcx.live_symbols_and_ignored_derived_traits(());
     let mut visitor = DeadVisitor { tcx, live_symbols, ignored_derived_traits };
 
@@ -969,7 +969,7 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalDefId) {
 
         if !live_symbols.contains(&item.owner_id.def_id) {
             let parent = tcx.local_parent(item.owner_id.def_id);
-            if parent != module && !live_symbols.contains(&parent) {
+            if parent != module.to_local_def_id() && !live_symbols.contains(&parent) {
                 // We already have diagnosed something.
                 continue;
             }
diff --git a/compiler/rustc_passes/src/loops.rs b/compiler/rustc_passes/src/loops.rs
index 7c64df6a50ecf..0aaf85086e455 100644
--- a/compiler/rustc_passes/src/loops.rs
+++ b/compiler/rustc_passes/src/loops.rs
@@ -1,7 +1,7 @@
 use Context::*;
 
 use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::LocalModDefId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Destination, Movability, Node};
 use rustc_middle::hir::map::Map;
@@ -34,7 +34,7 @@ struct CheckLoopVisitor<'a, 'hir> {
     cx: Context,
 }
 
-fn check_mod_loops(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_loops(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     tcx.hir().visit_item_likes_in_module(
         module_def_id,
         &mut CheckLoopVisitor { sess: &tcx.sess, hir_map: tcx.hir(), cx: Normal },
diff --git a/compiler/rustc_passes/src/naked_functions.rs b/compiler/rustc_passes/src/naked_functions.rs
index 769b389009b7e..7f36c59ad98d9 100644
--- a/compiler/rustc_passes/src/naked_functions.rs
+++ b/compiler/rustc_passes/src/naked_functions.rs
@@ -3,7 +3,7 @@
 use rustc_ast::InlineAsmOptions;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::{ExprKind, InlineAsmOperand, StmtKind};
 use rustc_middle::query::Providers;
@@ -23,7 +23,7 @@ pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers { check_mod_naked_functions, ..*providers };
 }
 
-fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let items = tcx.hir_module_items(module_def_id);
     for def_id in items.definitions() {
         if !matches!(tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn) {
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index bd2336410b954..9c265e8ec11e5 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -9,7 +9,7 @@ use rustc_attr::{
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::{LocalDefId, LocalModDefId, CRATE_DEF_ID};
 use rustc_hir::hir_id::CRATE_HIR_ID;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{FieldDef, Item, ItemKind, TraitRef, Ty, TyKind, Variant};
@@ -682,7 +682,7 @@ fn stability_index(tcx: TyCtxt<'_>, (): ()) -> Index {
 
 /// Cross-references the feature names of unstable APIs with enabled
 /// features and possibly prints errors.
-fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut Checker { tcx });
 }
 
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 30a4235d37145..0eb344ba69065 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -20,7 +20,7 @@ use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage};
 use rustc_fluent_macro::fluent_messages;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId, CRATE_DEF_ID};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{AssocItemKind, ForeignItemKind, HirIdSet, ItemId, Node, PatKind};
 use rustc_middle::bug;
@@ -382,8 +382,9 @@ impl VisibilityLike for EffectiveVisibility {
     ) -> Self {
         let effective_vis =
             find.effective_visibilities.effective_vis(def_id).copied().unwrap_or_else(|| {
-                let private_vis =
-                    ty::Visibility::Restricted(find.tcx.parent_module_from_def_id(def_id));
+                let private_vis = ty::Visibility::Restricted(
+                    find.tcx.parent_module_from_def_id(def_id).to_local_def_id(),
+                );
                 EffectiveVisibility::from_vis(private_vis)
             });
 
@@ -412,7 +413,7 @@ struct EmbargoVisitor<'tcx> {
     /// pub macro m() {
     ///     n::p::f()
     /// }
-    macro_reachable: FxHashSet<(LocalDefId, LocalDefId)>,
+    macro_reachable: FxHashSet<(LocalModDefId, LocalModDefId)>,
     /// Preliminary pass for marking all underlying types of `impl Trait`s as reachable.
     impl_trait_pass: bool,
     /// Has something changed in the level map?
@@ -449,7 +450,9 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         max_vis: Option<ty::Visibility>,
         level: Level,
     ) {
-        let private_vis = ty::Visibility::Restricted(self.tcx.parent_module_from_def_id(def_id));
+        // FIXME(typed_def_id): Make `Visibility::Restricted` use a `LocalModDefId` by default.
+        let private_vis =
+            ty::Visibility::Restricted(self.tcx.parent_module_from_def_id(def_id).into());
         if max_vis != Some(private_vis) {
             self.changed |= self.effective_visibilities.update(
                 def_id,
@@ -508,6 +511,8 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             // The macro's parent doesn't correspond to a `mod`, return early (#63164, #65252).
             return;
         }
+        // FIXME(typed_def_id): Introduce checked constructors that check def_kind.
+        let macro_module_def_id = LocalModDefId::new_unchecked(macro_module_def_id);
 
         if self.effective_visibilities.public_at_level(local_def_id).is_none() {
             return;
@@ -519,10 +524,10 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         loop {
             let changed_reachability =
                 self.update_macro_reachable(module_def_id, macro_module_def_id, macro_ev);
-            if changed_reachability || module_def_id == CRATE_DEF_ID {
+            if changed_reachability || module_def_id == LocalModDefId::CRATE_DEF_ID {
                 break;
             }
-            module_def_id = self.tcx.local_parent(module_def_id);
+            module_def_id = LocalModDefId::new_unchecked(self.tcx.local_parent(module_def_id));
         }
     }
 
@@ -530,8 +535,8 @@ impl<'tcx> EmbargoVisitor<'tcx> {
     /// module. Returns `true` if the level has changed.
     fn update_macro_reachable(
         &mut self,
-        module_def_id: LocalDefId,
-        defining_mod: LocalDefId,
+        module_def_id: LocalModDefId,
+        defining_mod: LocalModDefId,
         macro_ev: EffectiveVisibility,
     ) -> bool {
         if self.macro_reachable.insert((module_def_id, defining_mod)) {
@@ -544,8 +549,8 @@ impl<'tcx> EmbargoVisitor<'tcx> {
 
     fn update_macro_reachable_mod(
         &mut self,
-        module_def_id: LocalDefId,
-        defining_mod: LocalDefId,
+        module_def_id: LocalModDefId,
+        defining_mod: LocalModDefId,
         macro_ev: EffectiveVisibility,
     ) {
         let module = self.tcx.hir().get_module(module_def_id).0;
@@ -560,7 +565,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
                 macro_ev,
             );
         }
-        for child in self.tcx.module_children_local(module_def_id) {
+        for child in self.tcx.module_children_local(module_def_id.to_local_def_id()) {
             // FIXME: Use module children for the logic above too.
             if !child.reexport_chain.is_empty()
                 && child.vis.is_accessible_from(defining_mod, self.tcx)
@@ -577,7 +582,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         def_id: LocalDefId,
         def_kind: DefKind,
         vis: ty::Visibility,
-        module: LocalDefId,
+        module: LocalModDefId,
         macro_ev: EffectiveVisibility,
     ) {
         self.update(def_id, macro_ev, Level::Reachable);
@@ -608,7 +613,11 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             // the module, however may be reachable.
             DefKind::Mod => {
                 if vis.is_accessible_from(module, self.tcx) {
-                    self.update_macro_reachable(def_id, module, macro_ev);
+                    self.update_macro_reachable(
+                        LocalModDefId::new_unchecked(def_id),
+                        module,
+                        macro_ev,
+                    );
                 }
             }
 
@@ -892,7 +901,7 @@ fn vis_to_string<'tcx>(def_id: LocalDefId, vis: ty::Visibility, tcx: TyCtxt<'tcx
         ty::Visibility::Restricted(restricted_id) => {
             if restricted_id.is_top_level_module() {
                 "pub(crate)".to_string()
-            } else if restricted_id == tcx.parent_module_from_def_id(def_id) {
+            } else if restricted_id == tcx.parent_module_from_def_id(def_id).to_local_def_id() {
                 "pub(self)".to_string()
             } else {
                 format!("pub({})", tcx.item_name(restricted_id.to_def_id()))
@@ -1800,7 +1809,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
             let vis_descr = match vis {
                 ty::Visibility::Public => "public",
                 ty::Visibility::Restricted(vis_def_id) => {
-                    if vis_def_id == self.tcx.parent_module(hir_id) {
+                    if vis_def_id == self.tcx.parent_module(hir_id).to_local_def_id() {
                         "private"
                     } else if vis_def_id.is_top_level_module() {
                         "crate-private"
@@ -2196,7 +2205,7 @@ fn local_visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility {
                     kind: hir::ItemKind::Use(_, hir::UseKind::ListStem)
                         | hir::ItemKind::OpaqueTy(..),
                     ..
-                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id)),
+                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id).to_local_def_id()),
                 // Visibilities of trait impl items are inherited from their traits
                 // and are not filled in resolve.
                 Node::ImplItem(impl_item) => {
@@ -2224,18 +2233,25 @@ fn local_visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility {
     }
 }
 
-fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     // Check privacy of names not checked in previous compilation stages.
-    let mut visitor =
-        NamePrivacyVisitor { tcx, maybe_typeck_results: None, current_item: module_def_id };
+    let mut visitor = NamePrivacyVisitor {
+        tcx,
+        maybe_typeck_results: None,
+        current_item: module_def_id.to_local_def_id(),
+    };
     let (module, span, hir_id) = tcx.hir().get_module(module_def_id);
 
     intravisit::walk_mod(&mut visitor, module, hir_id);
 
     // Check privacy of explicitly written types and traits as well as
     // inferred types of expressions and patterns.
-    let mut visitor =
-        TypePrivacyVisitor { tcx, maybe_typeck_results: None, current_item: module_def_id, span };
+    let mut visitor = TypePrivacyVisitor {
+        tcx,
+        maybe_typeck_results: None,
+        current_item: module_def_id.to_local_def_id(),
+        span,
+    };
     intravisit::walk_mod(&mut visitor, module, hir_id);
 }
 
diff --git a/compiler/rustc_span/src/def_id.rs b/compiler/rustc_span/src/def_id.rs
index f65a6aa4fb21a..595babc26ae68 100644
--- a/compiler/rustc_span/src/def_id.rs
+++ b/compiler/rustc_span/src/def_id.rs
@@ -28,10 +28,16 @@ impl CrateNum {
         CrateNum::from_usize(x)
     }
 
+    // FIXME(typed_def_id): Replace this with `as_mod_def_id`.
     #[inline]
     pub fn as_def_id(self) -> DefId {
         DefId { krate: self, index: CRATE_DEF_INDEX }
     }
+
+    #[inline]
+    pub fn as_mod_def_id(self) -> ModDefId {
+        ModDefId::new_unchecked(DefId { krate: self, index: CRATE_DEF_INDEX })
+    }
 }
 
 impl fmt::Display for CrateNum {
@@ -485,3 +491,92 @@ impl<CTX: HashStableContext> ToStableHashKey<CTX> for CrateNum {
         self.as_def_id().to_stable_hash_key(hcx)
     }
 }
+
+macro_rules! typed_def_id {
+    ($Name:ident, $LocalName:ident) => {
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+        pub struct $Name(DefId);
+
+        impl $Name {
+            pub const fn new_unchecked(def_id: DefId) -> Self {
+                Self(def_id)
+            }
+
+            pub fn to_def_id(self) -> DefId {
+                self.into()
+            }
+
+            pub fn is_local(self) -> bool {
+                self.0.is_local()
+            }
+
+            pub fn as_local(self) -> Option<$LocalName> {
+                self.0.as_local().map($LocalName::new_unchecked)
+            }
+        }
+
+        impl From<$LocalName> for $Name {
+            fn from(local: $LocalName) -> Self {
+                Self(local.0.to_def_id())
+            }
+        }
+
+        impl From<$Name> for DefId {
+            fn from(typed: $Name) -> Self {
+                typed.0
+            }
+        }
+
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+        pub struct $LocalName(LocalDefId);
+
+        impl !Ord for $LocalName {}
+        impl !PartialOrd for $LocalName {}
+
+        impl $LocalName {
+            pub const fn new_unchecked(def_id: LocalDefId) -> Self {
+                Self(def_id)
+            }
+
+            pub fn to_def_id(self) -> DefId {
+                self.0.into()
+            }
+
+            pub fn to_local_def_id(self) -> LocalDefId {
+                self.0
+            }
+        }
+
+        impl From<$LocalName> for LocalDefId {
+            fn from(typed: $LocalName) -> Self {
+                typed.0
+            }
+        }
+
+        impl From<$LocalName> for DefId {
+            fn from(typed: $LocalName) -> Self {
+                typed.0.into()
+            }
+        }
+    };
+}
+
+// N.B.: when adding new typed `DefId`s update the corresponding trait impls in
+// `rustc_middle::dep_graph::def_node` for `DepNodeParams`.
+typed_def_id! { ModDefId, LocalModDefId }
+
+impl LocalModDefId {
+    pub const CRATE_DEF_ID: Self = Self::new_unchecked(CRATE_DEF_ID);
+}
+
+impl ModDefId {
+    pub fn is_top_level_module(self) -> bool {
+        self.0.is_top_level_module()
+    }
+}
+
+impl LocalModDefId {
+    pub fn is_top_level_module(self) -> bool {
+        self.0.is_top_level_module()
+    }
+}
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 6ada4e4908353..af2b96ccb5154 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -338,7 +338,7 @@ impl LinkerFlavor {
             || stem == "clang++"
             || stem.ends_with("-clang++")
         {
-            (Some(Cc::Yes), None)
+            (Some(Cc::Yes), Some(Lld::No))
         } else if stem == "wasm-ld"
             || stem.ends_with("-wasm-ld")
             || stem == "ld.lld"
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 3750b3750bff1..36194f973b572 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -281,23 +281,27 @@ pub(super) trait GoalKind<'tcx>:
     ) -> QueryResult<'tcx>;
 
     /// Consider (possibly several) candidates to upcast or unsize a type to another
-    /// type.
-    ///
-    /// The most common forms of unsizing are array to slice, and concrete (Sized)
-    /// type into a `dyn Trait`. ADTs and Tuples can also have their final field
-    /// unsized if it's generic.
-    ///
-    /// `dyn Trait1` can be unsized to `dyn Trait2` if they are the same trait, or
-    /// if `Trait2` is a (transitive) supertrait of `Trait2`.
+    /// type, excluding the coercion of a sized type into a `dyn Trait`.
     ///
     /// We return the `BuiltinImplSource` for each candidate as it is needed
     /// for unsize coercion in hir typeck and because it is difficult to
     /// otherwise recompute this for codegen. This is a bit of a mess but the
     /// easiest way to maintain the existing behavior for now.
-    fn consider_builtin_unsize_candidates(
+    fn consider_structural_builtin_unsize_candidates(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
     ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)>;
+
+    /// Consider the `Unsize` candidate corresponding to coercing a sized type
+    /// into a `dyn Trait`.
+    ///
+    /// This is computed separately from the rest of the `Unsize` candidates
+    /// since it is only done once per self type, and not once per
+    /// *normalization step* (in `assemble_candidates_via_self_ty`).
+    fn consider_unsize_to_dyn_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
@@ -312,6 +316,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
         let mut candidates = self.assemble_candidates_via_self_ty(goal, 0);
 
+        self.assemble_unsize_to_dyn_candidate(goal, &mut candidates);
+
         self.assemble_blanket_impl_candidates(goal, &mut candidates);
 
         self.assemble_param_env_candidates(goal, &mut candidates);
@@ -530,6 +536,23 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    fn assemble_unsize_to_dyn_candidate<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let tcx = self.tcx();
+        if tcx.lang_items().unsize_trait() == Some(goal.predicate.trait_def_id(tcx)) {
+            match G::consider_unsize_to_dyn_candidate(self, goal) {
+                Ok(result) => candidates.push(Candidate {
+                    source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
+                    result,
+                }),
+                Err(NoSolution) => (),
+            }
+        }
+    }
+
     fn assemble_blanket_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -610,7 +633,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         // There may be multiple unsize candidates for a trait with several supertraits:
         // `trait Foo: Bar<A> + Bar<B>` and `dyn Foo: Unsize<dyn Bar<_>>`
         if lang_items.unsize_trait() == Some(trait_def_id) {
-            for (result, source) in G::consider_builtin_unsize_candidates(self, goal) {
+            for (result, source) in G::consider_structural_builtin_unsize_candidates(self, goal) {
                 candidates.push(Candidate { source: CandidateSource::BuiltinImpl(source), result });
             }
         }
@@ -826,6 +849,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             ty::Dynamic(bounds, ..) => bounds,
         };
 
+        // Do not consider built-in object impls for non-object-safe types.
+        if bounds.principal_def_id().is_some_and(|def_id| !tcx.check_is_object_safe(def_id)) {
+            return;
+        }
+
         // Consider all of the auto-trait and projection bounds, which don't
         // need to be recorded as a `BuiltinImplSource::Object` since they don't
         // really have a vtable base...
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index e1980f4d7bb0e..e47e228774e07 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -1,4 +1,4 @@
-use crate::traits::specialization_graph;
+use crate::traits::{check_args_compatible, specialization_graph};
 
 use super::assembly::{self, structural_traits};
 use super::EvalCtxt;
@@ -190,11 +190,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
             };
 
-            if !assoc_def.item.defaultness(tcx).has_value() {
-                let guar = tcx.sess.delay_span_bug(
-                    tcx.def_span(assoc_def.item.def_id),
-                    "missing value for assoc item in impl",
-                );
+            let error_response = |ecx: &mut EvalCtxt<'_, 'tcx>, reason| {
+                let guar = tcx.sess.delay_span_bug(tcx.def_span(assoc_def.item.def_id), reason);
                 let error_term = match assoc_def.item.kind {
                     ty::AssocKind::Const => ty::Const::new_error(
                         tcx,
@@ -208,7 +205,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 };
                 ecx.eq(goal.param_env, goal.predicate.term, error_term)
                     .expect("expected goal term to be fully unconstrained");
-                return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
+                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+            };
+
+            if !assoc_def.item.defaultness(tcx).has_value() {
+                return error_response(ecx, "missing value for assoc item in impl");
             }
 
             // Getting the right args here is complex, e.g. given:
@@ -233,6 +234,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 assoc_def.defining_node,
             );
 
+            if !check_args_compatible(tcx, assoc_def.item, args) {
+                return error_response(
+                    ecx,
+                    "associated item has mismatched generic item arguments",
+                );
+            }
+
             // Finally we construct the actual value of the associated type.
             let term = match assoc_def.item.kind {
                 ty::AssocKind::Type => tcx.type_of(assoc_def.item.def_id).map_bound(|ty| ty.into()),
@@ -497,7 +505,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
         )
     }
 
-    fn consider_builtin_unsize_candidates(
+    fn consider_unsize_to_dyn_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`Unsize` does not have an associated type: {:?}", goal)
+    }
+
+    fn consider_structural_builtin_unsize_candidates(
         _ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
     ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> {
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index ee6f1686b8238..8685f3100a822 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -423,7 +423,55 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
         ecx.evaluate_added_goals_and_make_canonical_response(certainty)
     }
 
-    fn consider_builtin_unsize_candidates(
+    fn consider_unsize_to_dyn_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        ecx.probe(|_| CandidateKind::UnsizeAssembly).enter(|ecx| {
+            let a_ty = goal.predicate.self_ty();
+            // We need to normalize the b_ty since it's destructured as a `dyn Trait`.
+            let Some(b_ty) =
+                ecx.try_normalize_ty(goal.param_env, goal.predicate.trait_ref.args.type_at(1))?
+            else {
+                return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::OVERFLOW);
+            };
+
+            let ty::Dynamic(b_data, b_region, ty::Dyn) = *b_ty.kind() else {
+                return Err(NoSolution);
+            };
+
+            let tcx = ecx.tcx();
+
+            // Can only unsize to an object-safe trait.
+            if b_data.principal_def_id().is_some_and(|def_id| !tcx.check_is_object_safe(def_id)) {
+                return Err(NoSolution);
+            }
+
+            // Check that the type implements all of the predicates of the trait object.
+            // (i.e. the principal, all of the associated types match, and any auto traits)
+            ecx.add_goals(b_data.iter().map(|pred| goal.with(tcx, pred.with_self_ty(tcx, a_ty))));
+
+            // The type must be `Sized` to be unsized.
+            if let Some(sized_def_id) = tcx.lang_items().sized_trait() {
+                ecx.add_goal(goal.with(tcx, ty::TraitRef::new(tcx, sized_def_id, [a_ty])));
+            } else {
+                return Err(NoSolution);
+            }
+
+            // The type must outlive the lifetime of the `dyn` we're unsizing into.
+            ecx.add_goal(goal.with(tcx, ty::OutlivesPredicate(a_ty, b_region)));
+            ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+        })
+    }
+
+    /// ```ignore (builtin impl example)
+    /// trait Trait {
+    ///     fn foo(&self);
+    /// }
+    /// // results in the following builtin impl
+    /// impl<'a, T: Trait + 'a> Unsize<dyn Trait + 'a> for T {}
+    /// ```
+    fn consider_structural_builtin_unsize_candidates(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
     ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> {
@@ -468,11 +516,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
                     goal, a_data, a_region, b_data, b_region,
                 ),
 
-                // `T` -> `dyn Trait` unsizing
-                (_, &ty::Dynamic(b_data, b_region, ty::Dyn)) => result_to_single(
-                    ecx.consider_builtin_unsize_to_dyn(goal, b_data, b_region),
-                    BuiltinImplSource::Misc,
-                ),
+                // `T` -> `dyn Trait` unsizing is handled separately in `consider_unsize_to_dyn_candidate`
+                (_, &ty::Dynamic(..)) => vec![],
 
                 // `[T; N]` -> `[T]` unsizing
                 (&ty::Array(a_elem_ty, ..), &ty::Slice(b_elem_ty)) => result_to_single(
@@ -552,16 +597,18 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             self.walk_vtable(
                 a_principal.with_self_ty(tcx, a_ty),
                 |ecx, new_a_principal, _, vtable_vptr_slot| {
-                    if let Ok(resp) = ecx.consider_builtin_upcast_to_principal(
-                        goal,
-                        a_data,
-                        a_region,
-                        b_data,
-                        b_region,
-                        Some(new_a_principal.map_bound(|trait_ref| {
-                            ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
-                        })),
-                    ) {
+                    if let Ok(resp) = ecx.probe_candidate("dyn upcast").enter(|ecx| {
+                        ecx.consider_builtin_upcast_to_principal(
+                            goal,
+                            a_data,
+                            a_region,
+                            b_data,
+                            b_region,
+                            Some(new_a_principal.map_bound(|trait_ref| {
+                                ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
+                            })),
+                        )
+                    }) {
                         responses
                             .push((resp, BuiltinImplSource::TraitUpcasting { vtable_vptr_slot }));
                     }
@@ -572,43 +619,6 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         responses
     }
 
-    /// ```ignore (builtin impl example)
-    /// trait Trait {
-    ///     fn foo(&self);
-    /// }
-    /// // results in the following builtin impl
-    /// impl<'a, T: Trait + 'a> Unsize<dyn Trait + 'a> for T {}
-    /// ```
-    fn consider_builtin_unsize_to_dyn(
-        &mut self,
-        goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>,
-        b_data: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
-        b_region: ty::Region<'tcx>,
-    ) -> QueryResult<'tcx> {
-        let tcx = self.tcx();
-        let Goal { predicate: (a_ty, _b_ty), .. } = goal;
-
-        // Can only unsize to an object-safe trait
-        if b_data.principal_def_id().is_some_and(|def_id| !tcx.check_is_object_safe(def_id)) {
-            return Err(NoSolution);
-        }
-
-        // Check that the type implements all of the predicates of the trait object.
-        // (i.e. the principal, all of the associated types match, and any auto traits)
-        self.add_goals(b_data.iter().map(|pred| goal.with(tcx, pred.with_self_ty(tcx, a_ty))));
-
-        // The type must be `Sized` to be unsized.
-        if let Some(sized_def_id) = tcx.lang_items().sized_trait() {
-            self.add_goal(goal.with(tcx, ty::TraitRef::new(tcx, sized_def_id, [a_ty])));
-        } else {
-            return Err(NoSolution);
-        }
-
-        // The type must outlive the lifetime of the `dyn` we're unsizing into.
-        self.add_goal(goal.with(tcx, ty::OutlivesPredicate(a_ty, b_region)));
-        self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
-    }
-
     fn consider_builtin_upcast_to_principal(
         &mut self,
         goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>,
diff --git a/library/core/src/ffi/c_str.rs b/library/core/src/ffi/c_str.rs
index b59ec12790d24..4082b208c1263 100644
--- a/library/core/src/ffi/c_str.rs
+++ b/library/core/src/ffi/c_str.rs
@@ -82,12 +82,12 @@ use crate::str;
 #[stable(feature = "core_c_str", since = "1.64.0")]
 #[rustc_has_incoherent_inherent_impls]
 #[lang = "CStr"]
-// FIXME:
 // `fn from` in `impl From<&CStr> for Box<CStr>` current implementation relies
 // on `CStr` being layout-compatible with `[u8]`.
-// When attribute privacy is implemented, `CStr` should be annotated as `#[repr(transparent)]`.
-// Anyway, `CStr` representation and layout are considered implementation detail, are
-// not documented and must not be relied upon.
+// However, `CStr` layout is considered an implementation detail and must not be relied upon. We
+// want `repr(transparent)` but we don't want it to show up in rustdoc, so we hide it under
+// `cfg(doc)`. This is an ad-hoc implementation of attribute privacy.
+#[cfg_attr(not(doc), repr(transparent))]
 pub struct CStr {
     // FIXME: this should not be represented with a DST slice but rather with
     //        just a raw `c_char` along with some form of marker to make
diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index 67e58fd1b8613..43cecb19b148e 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -110,12 +110,12 @@ impl crate::sealed::Sealed for OsString {}
 /// [conversions]: super#conversions
 #[cfg_attr(not(test), rustc_diagnostic_item = "OsStr")]
 #[stable(feature = "rust1", since = "1.0.0")]
-// FIXME:
 // `OsStr::from_inner` current implementation relies
 // on `OsStr` being layout-compatible with `Slice`.
-// When attribute privacy is implemented, `OsStr` should be annotated as `#[repr(transparent)]`.
-// Anyway, `OsStr` representation and layout are considered implementation details, are
-// not documented and must not be relied upon.
+// However, `OsStr` layout is considered an implementation detail and must not be relied upon. We
+// want `repr(transparent)` but we don't want it to show up in rustdoc, so we hide it under
+// `cfg(doc)`. This is an ad-hoc implementation of attribute privacy.
+#[cfg_attr(not(doc), repr(transparent))]
 pub struct OsStr {
     inner: Slice,
 }
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 99f7a60f8ab01..5842c096f1ab7 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1158,12 +1158,12 @@ impl FusedIterator for Ancestors<'_> {}
 /// Which method works best depends on what kind of situation you're in.
 #[cfg_attr(not(test), rustc_diagnostic_item = "PathBuf")]
 #[stable(feature = "rust1", since = "1.0.0")]
-// FIXME:
 // `PathBuf::as_mut_vec` current implementation relies
 // on `PathBuf` being layout-compatible with `Vec<u8>`.
-// When attribute privacy is implemented, `PathBuf` should be annotated as `#[repr(transparent)]`.
-// Anyway, `PathBuf` representation and layout are considered implementation detail, are
-// not documented and must not be relied upon.
+// However, `PathBuf` layout is considered an implementation detail and must not be relied upon. We
+// want `repr(transparent)` but we don't want it to show up in rustdoc, so we hide it under
+// `cfg(doc)`. This is an ad-hoc implementation of attribute privacy.
+#[cfg_attr(not(doc), repr(transparent))]
 pub struct PathBuf {
     inner: OsString,
 }
@@ -1983,12 +1983,12 @@ impl AsRef<OsStr> for PathBuf {
 /// ```
 #[cfg_attr(not(test), rustc_diagnostic_item = "Path")]
 #[stable(feature = "rust1", since = "1.0.0")]
-// FIXME:
 // `Path::new` current implementation relies
 // on `Path` being layout-compatible with `OsStr`.
-// When attribute privacy is implemented, `Path` should be annotated as `#[repr(transparent)]`.
-// Anyway, `Path` representation and layout are considered implementation detail, are
-// not documented and must not be relied upon.
+// However, `Path` layout is considered an implementation detail and must not be relied upon. We
+// want `repr(transparent)` but we don't want it to show up in rustdoc, so we hide it under
+// `cfg(doc)`. This is an ad-hoc implementation of attribute privacy.
+#[cfg_attr(not(doc), repr(transparent))]
 pub struct Path {
     inner: OsStr,
 }
diff --git a/library/std/src/sys/wasi/fd.rs b/library/std/src/sys/wasi/fd.rs
index 1b50c2ea6dd57..d7295a799daab 100644
--- a/library/std/src/sys/wasi/fd.rs
+++ b/library/std/src/sys/wasi/fd.rs
@@ -16,14 +16,20 @@ pub struct WasiFd {
 fn iovec<'a>(a: &'a mut [IoSliceMut<'_>]) -> &'a [wasi::Iovec] {
     assert_eq!(mem::size_of::<IoSliceMut<'_>>(), mem::size_of::<wasi::Iovec>());
     assert_eq!(mem::align_of::<IoSliceMut<'_>>(), mem::align_of::<wasi::Iovec>());
-    // SAFETY: `IoSliceMut` and `IoVec` have exactly the same memory layout
+    // SAFETY: `IoSliceMut` and `IoVec` have exactly the same memory layout.
+    // We decorate our `IoSliceMut` with `repr(transparent)` (see `io.rs`), and
+    // `crate::io::IoSliceMut` is a `repr(transparent)` wrapper around our type, so this is
+    // guaranteed.
     unsafe { mem::transmute(a) }
 }
 
 fn ciovec<'a>(a: &'a [IoSlice<'_>]) -> &'a [wasi::Ciovec] {
     assert_eq!(mem::size_of::<IoSlice<'_>>(), mem::size_of::<wasi::Ciovec>());
     assert_eq!(mem::align_of::<IoSlice<'_>>(), mem::align_of::<wasi::Ciovec>());
-    // SAFETY: `IoSlice` and `CIoVec` have exactly the same memory layout
+    // SAFETY: `IoSlice` and `CIoVec` have exactly the same memory layout.
+    // We decorate our `IoSlice` with `repr(transparent)` (see `io.rs`), and
+    // `crate::io::IoSlice` is a `repr(transparent)` wrapper around our type, so this is
+    // guaranteed.
     unsafe { mem::transmute(a) }
 }
 
diff --git a/library/std/src/sys_common/wtf8.rs b/library/std/src/sys_common/wtf8.rs
index 195d175cc9bde..67db5ebd89cfc 100644
--- a/library/std/src/sys_common/wtf8.rs
+++ b/library/std/src/sys_common/wtf8.rs
@@ -459,6 +459,7 @@ impl Wtf8Buf {
     /// Converts this `Wtf8Buf` into a boxed `Wtf8`.
     #[inline]
     pub fn into_box(self) -> Box<Wtf8> {
+        // SAFETY: relies on `Wtf8` being `repr(transparent)`.
         unsafe { mem::transmute(self.bytes.into_boxed_slice()) }
     }
 
@@ -511,6 +512,7 @@ impl Extend<CodePoint> for Wtf8Buf {
 /// Similar to `&str`, but can additionally contain surrogate code points
 /// if they’re not in a surrogate pair.
 #[derive(Eq, Ord, PartialEq, PartialOrd)]
+#[repr(transparent)]
 pub struct Wtf8 {
     bytes: [u8],
 }
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 389bac0f09dbc..2456e8818eba5 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -9,7 +9,7 @@ use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, DefIdSet, LocalDefId};
+use rustc_hir::def_id::{DefId, DefIdSet, LocalModDefId};
 use rustc_hir::Mutability;
 use rustc_metadata::creader::{CStore, LoadedMacro};
 use rustc_middle::ty::fast_reject::SimplifiedType;
@@ -138,7 +138,7 @@ pub(crate) fn try_inline(
 pub(crate) fn try_inline_glob(
     cx: &mut DocContext<'_>,
     res: Res,
-    current_mod: LocalDefId,
+    current_mod: LocalModDefId,
     visited: &mut DefIdSet,
     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
     import: &hir::Item<'_>,
@@ -154,7 +154,7 @@ pub(crate) fn try_inline_glob(
             // reexported by the glob, e.g. because they are shadowed by something else.
             let reexports = cx
                 .tcx
-                .module_children_local(current_mod)
+                .module_children_local(current_mod.to_local_def_id())
                 .iter()
                 .filter(|child| !child.reexport_chain.is_empty())
                 .filter_map(|child| child.res.opt_def_id())
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index b6ba4c853d4cd..624f1620f2cb8 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1551,7 +1551,7 @@ fn first_non_private<'tcx>(
         }
         [parent, leaf] if parent.ident.name == kw::Super => {
             let parent_mod = cx.tcx.parent_module(hir_id);
-            if let Some(super_parent) = cx.tcx.opt_local_parent(parent_mod) {
+            if let Some(super_parent) = cx.tcx.opt_local_parent(parent_mod.to_local_def_id()) {
                 (super_parent, leaf.ident)
             } else {
                 // If we can't find the parent of the parent, then the parent is already the crate.
@@ -2828,7 +2828,7 @@ fn clean_use_statement_inner<'tcx>(
     // The parent of the module in which this import resides. This
     // is the same as `current_mod` if that's already the top
     // level module.
-    let parent_mod = cx.tcx.parent_module_from_def_id(current_mod);
+    let parent_mod = cx.tcx.parent_module_from_def_id(current_mod.to_local_def_id());
 
     // This checks if the import can be seen from a higher level module.
     // In other words, it checks if the visibility is the equivalent of
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 171b7faf21960..b77a2f1d0cd05 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -83,7 +83,7 @@ use rustc_ast::Attribute;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalModDefId, LOCAL_CRATE};
 use rustc_hir::hir_id::{HirIdMap, HirIdSet};
 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
 use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
@@ -2370,11 +2370,11 @@ pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
     false
 }
 
-static TEST_ITEM_NAMES_CACHE: OnceLock<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = OnceLock::new();
+static TEST_ITEM_NAMES_CACHE: OnceLock<Mutex<FxHashMap<LocalModDefId, Vec<Symbol>>>> = OnceLock::new();
 
-fn with_test_item_names(tcx: TyCtxt<'_>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
+fn with_test_item_names(tcx: TyCtxt<'_>, module: LocalModDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
     let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
-    let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
+    let mut map: MutexGuard<'_, FxHashMap<LocalModDefId, Vec<Symbol>>> = cache.lock().unwrap();
     let value = map.entry(module);
     match value {
         Entry::Occupied(entry) => f(entry.get()),
diff --git a/tests/ui/generic-associated-types/issue-102114.stderr b/tests/ui/generic-associated-types/issue-102114.current.stderr
similarity index 91%
rename from tests/ui/generic-associated-types/issue-102114.stderr
rename to tests/ui/generic-associated-types/issue-102114.current.stderr
index 8e41dee54d7e4..6e7a0b1f67f71 100644
--- a/tests/ui/generic-associated-types/issue-102114.stderr
+++ b/tests/ui/generic-associated-types/issue-102114.current.stderr
@@ -1,5 +1,5 @@
 error[E0049]: type `B` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/issue-102114.rs:11:12
+  --> $DIR/issue-102114.rs:14:12
    |
 LL |     type B<'b>;
    |            -- expected 0 type parameters
diff --git a/tests/ui/generic-associated-types/issue-102114.next.stderr b/tests/ui/generic-associated-types/issue-102114.next.stderr
new file mode 100644
index 0000000000000..6e7a0b1f67f71
--- /dev/null
+++ b/tests/ui/generic-associated-types/issue-102114.next.stderr
@@ -0,0 +1,12 @@
+error[E0049]: type `B` has 1 type parameter but its trait declaration has 0 type parameters
+  --> $DIR/issue-102114.rs:14:12
+   |
+LL |     type B<'b>;
+   |            -- expected 0 type parameters
+...
+LL |     type B<T> = Wrapper<T>;
+   |            ^ found 1 type parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0049`.
diff --git a/tests/ui/generic-associated-types/issue-102114.rs b/tests/ui/generic-associated-types/issue-102114.rs
index de31737efef52..bb6622c0a5fb7 100644
--- a/tests/ui/generic-associated-types/issue-102114.rs
+++ b/tests/ui/generic-associated-types/issue-102114.rs
@@ -1,3 +1,6 @@
+// revisions: current next
+//[next] compile-flags: -Ztrait-solver=next
+
 trait A {
     type B<'b>;
     fn a() -> Self::B<'static>;
diff --git a/tests/ui/generic-associated-types/issue-86218.rs b/tests/ui/generic-associated-types/issue-86218.rs
index 61cfdd35a8926..397a0f2c64903 100644
--- a/tests/ui/generic-associated-types/issue-86218.rs
+++ b/tests/ui/generic-associated-types/issue-86218.rs
@@ -17,7 +17,6 @@ trait Yay<AdditionalValue> {
 
 impl<'a> Yay<&'a ()> for () {
     type InnerStream<'s> = impl Stream<Item = i32> + 's;
-    //^ ERROR does not fulfill the required lifetime
     fn foo<'s>() -> Self::InnerStream<'s> {
         ()
     }
diff --git a/tests/ui/generic-associated-types/issue-90014-tait.rs b/tests/ui/generic-associated-types/issue-90014-tait.rs
index bc3a4e1296513..1ce5cd3198767 100644
--- a/tests/ui/generic-associated-types/issue-90014-tait.rs
+++ b/tests/ui/generic-associated-types/issue-90014-tait.rs
@@ -13,7 +13,6 @@ struct Foo<'a>(&'a mut ());
 
 impl Foo<'_> {
     type Fut<'a> = impl Future<Output = ()>;
-    //^ ERROR: the type `&mut ()` does not fulfill the required lifetime
 
     fn make_fut<'a>(&'a self) -> Self::Fut<'a> {
         async { () }
diff --git a/tests/ui/generic-associated-types/issue-90014-tait.stderr b/tests/ui/generic-associated-types/issue-90014-tait.stderr
index 8330a387ecd55..1dec7edce508c 100644
--- a/tests/ui/generic-associated-types/issue-90014-tait.stderr
+++ b/tests/ui/generic-associated-types/issue-90014-tait.stderr
@@ -1,18 +1,18 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-90014-tait.rs:19:9
+  --> $DIR/issue-90014-tait.rs:18:9
    |
 LL |     type Fut<'a> = impl Future<Output = ()>;
    |                    ------------------------ the expected future
-...
+LL |
 LL |     fn make_fut<'a>(&'a self) -> Self::Fut<'a> {
    |                                  ------------- expected `Foo<'_>::Fut<'a>` because of return type
 LL |         async { () }
    |         ^^^^^^^^^^^^ expected future, found `async` block
    |
    = note: expected opaque type `Foo<'_>::Fut<'a>`
-            found `async` block `[async block@$DIR/issue-90014-tait.rs:19:9: 19:21]`
+            found `async` block `[async block@$DIR/issue-90014-tait.rs:18:9: 18:21]`
 note: this item must have the opaque type in its signature in order to be able to register hidden types
-  --> $DIR/issue-90014-tait.rs:18:8
+  --> $DIR/issue-90014-tait.rs:17:8
    |
 LL |     fn make_fut<'a>(&'a self) -> Self::Fut<'a> {
    |        ^^^^^^^^
diff --git a/tests/ui/internal/internal-unstable.rs b/tests/ui/internal/internal-unstable.rs
index b8987d3e13c65..1eb27fbdc3a63 100644
--- a/tests/ui/internal/internal-unstable.rs
+++ b/tests/ui/internal/internal-unstable.rs
@@ -8,7 +8,6 @@ extern crate internal_unstable;
 
 struct Baz {
     #[allow_internal_unstable]
-    //^ WARN `#[allow_internal_unstable]` is ignored on struct fields and match arms
     baz: u8,
 }
 
@@ -50,7 +49,6 @@ fn main() {
 
     match true {
         #[allow_internal_unstable]
-        //^ WARN `#[allow_internal_unstable]` is ignored on struct fields and match arms
         _ => {}
     }
 }
diff --git a/tests/ui/internal/internal-unstable.stderr b/tests/ui/internal/internal-unstable.stderr
index f0f9bfb8d234f..b7c47365c2d27 100644
--- a/tests/ui/internal/internal-unstable.stderr
+++ b/tests/ui/internal/internal-unstable.stderr
@@ -1,5 +1,5 @@
 error[E0658]: use of unstable library feature 'function'
-  --> $DIR/internal-unstable.rs:41:25
+  --> $DIR/internal-unstable.rs:40:25
    |
 LL |     pass_through_allow!(internal_unstable::unstable());
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL |     pass_through_allow!(internal_unstable::unstable());
    = help: add `#![feature(function)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'function'
-  --> $DIR/internal-unstable.rs:43:27
+  --> $DIR/internal-unstable.rs:42:27
    |
 LL |     pass_through_noallow!(internal_unstable::unstable());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -15,7 +15,7 @@ LL |     pass_through_noallow!(internal_unstable::unstable());
    = help: add `#![feature(function)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'function'
-  --> $DIR/internal-unstable.rs:47:22
+  --> $DIR/internal-unstable.rs:46:22
    |
 LL |     println!("{:?}", internal_unstable::unstable());
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -23,7 +23,7 @@ LL |     println!("{:?}", internal_unstable::unstable());
    = help: add `#![feature(function)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'function'
-  --> $DIR/internal-unstable.rs:49:10
+  --> $DIR/internal-unstable.rs:48:10
    |
 LL |     bar!(internal_unstable::unstable());
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -31,7 +31,7 @@ LL |     bar!(internal_unstable::unstable());
    = help: add `#![feature(function)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'function'
-  --> $DIR/internal-unstable.rs:19:9
+  --> $DIR/internal-unstable.rs:18:9
    |
 LL |         internal_unstable::unstable();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/lint/unknown-lints/allow-in-other-module.rs b/tests/ui/lint/unknown-lints/allow-in-other-module.rs
new file mode 100644
index 0000000000000..20bf0d7af03cb
--- /dev/null
+++ b/tests/ui/lint/unknown-lints/allow-in-other-module.rs
@@ -0,0 +1,26 @@
+// check-pass
+
+// Tests that the unknown_lints lint doesn't fire for an unknown lint loaded from a separate file.
+// The key part is that the stderr output should be empty.
+// Reported in https://github.com/rust-lang/rust/issues/84936
+// Fixed incidentally by https://github.com/rust-lang/rust/pull/97266
+
+// This `allow` should apply to submodules, whether they are inline or loaded from a file.
+#![allow(unknown_lints)]
+#![allow(dead_code)]
+// no warning
+#![allow(not_a_real_lint)]
+
+mod other;
+
+// no warning
+#[allow(not_a_real_lint)]
+fn m() {}
+
+mod mm {
+    // no warning
+    #[allow(not_a_real_lint)]
+    fn m() {}
+}
+
+fn main() {}
diff --git a/tests/ui/lint/unknown-lints/other.rs b/tests/ui/lint/unknown-lints/other.rs
new file mode 100644
index 0000000000000..a5111c00a3ecf
--- /dev/null
+++ b/tests/ui/lint/unknown-lints/other.rs
@@ -0,0 +1,10 @@
+// ignore-test
+
+// Companion to allow-in-other-module.rs
+
+// This should not warn.
+#![allow(not_a_real_lint)]
+
+// This should not warn, either.
+#[allow(not_a_real_lint)]
+fn m() {}
diff --git a/tests/ui/parser/issues/issue-70583-block-is-empty-2.rs b/tests/ui/parser/issues/issue-70583-block-is-empty-2.rs
index 80f53338a689e..92ff0ef643e34 100644
--- a/tests/ui/parser/issues/issue-70583-block-is-empty-2.rs
+++ b/tests/ui/parser/issues/issue-70583-block-is-empty-2.rs
@@ -6,9 +6,13 @@ pub enum ErrorHandled {
 impl ErrorHandled {
     pub fn assert_reported(self) {
         match self {
+            //~^ NOTE this delimiter might not be properly closed...
             ErrorHandled::Reported => {}}
-                                     //^~ ERROR block is empty, you might have not meant to close it
+                                     //~^ NOTE block is empty, you might have not meant to close it
+                                     //~| NOTE as it matches this but it has different indentation
             ErrorHandled::TooGeneric => panic!(),
         }
     }
-} //~ ERROR unexpected closing delimiter: `}`
+}
+//~^ ERROR unexpected closing delimiter: `}`
+//~| NOTE unexpected closing delimiter
diff --git a/tests/ui/parser/issues/issue-70583-block-is-empty-2.stderr b/tests/ui/parser/issues/issue-70583-block-is-empty-2.stderr
index 9ae94c701869b..c590e04bb3ded 100644
--- a/tests/ui/parser/issues/issue-70583-block-is-empty-2.stderr
+++ b/tests/ui/parser/issues/issue-70583-block-is-empty-2.stderr
@@ -1,8 +1,9 @@
 error: unexpected closing delimiter: `}`
-  --> $DIR/issue-70583-block-is-empty-2.rs:14:1
+  --> $DIR/issue-70583-block-is-empty-2.rs:16:1
    |
 LL |         match self {
    |                    - this delimiter might not be properly closed...
+LL |
 LL |             ErrorHandled::Reported => {}}
    |                                       --- ...as it matches this but it has different indentation
    |                                       |
diff --git a/tests/ui/rfcs/rfc-2027-object-safe-for-dispatch/manual-self-impl-for-unsafe-obj.rs b/tests/ui/rfcs/rfc-2027-object-safe-for-dispatch/manual-self-impl-for-unsafe-obj.rs
index 721890db4fbd7..c27e8c4b01972 100644
--- a/tests/ui/rfcs/rfc-2027-object-safe-for-dispatch/manual-self-impl-for-unsafe-obj.rs
+++ b/tests/ui/rfcs/rfc-2027-object-safe-for-dispatch/manual-self-impl-for-unsafe-obj.rs
@@ -1,5 +1,7 @@
 // Check that we can manually implement an object-unsafe trait for its trait object.
 
+// revisions: current next
+//[next] compile-flags: -Ztrait-solver=next
 // run-pass
 
 #![feature(object_safe_for_dispatch)]
diff --git a/tests/ui/std/slice-from-array-issue-113238.rs b/tests/ui/std/slice-from-array-issue-113238.rs
new file mode 100644
index 0000000000000..e9e1bfb8db308
--- /dev/null
+++ b/tests/ui/std/slice-from-array-issue-113238.rs
@@ -0,0 +1,9 @@
+// check-pass
+
+// This intends to use the unsizing coercion from array to slice, but it only
+// works if we resolve `<&[u8]>::from` as the reflexive `From<T> for T`. In
+// #113238, we found that gimli had added its own `From<EndianSlice> for &[u8]`
+// that affected all `std/backtrace` users.
+fn main() {
+    let _ = <&[u8]>::from(&[]);
+}
diff --git a/tests/ui/traits/trait-upcasting/type-checking-test-1.stderr b/tests/ui/traits/trait-upcasting/type-checking-test-1.current.stderr
similarity index 89%
rename from tests/ui/traits/trait-upcasting/type-checking-test-1.stderr
rename to tests/ui/traits/trait-upcasting/type-checking-test-1.current.stderr
index 82b4e9bd72aec..d48d9b89d1dac 100644
--- a/tests/ui/traits/trait-upcasting/type-checking-test-1.stderr
+++ b/tests/ui/traits/trait-upcasting/type-checking-test-1.current.stderr
@@ -1,5 +1,5 @@
 error[E0605]: non-primitive cast: `&dyn Foo` as `&dyn Bar<_>`
-  --> $DIR/type-checking-test-1.rs:16:13
+  --> $DIR/type-checking-test-1.rs:19:13
    |
 LL |     let _ = x as &dyn Bar<_>; // Ambiguous
    |             ^^^^^^^^^^^^^^^^ invalid cast
@@ -10,7 +10,7 @@ LL |     let _ = &x as &dyn Bar<_>; // Ambiguous
    |             +
 
 error[E0277]: the trait bound `&dyn Foo: Bar<_>` is not satisfied
-  --> $DIR/type-checking-test-1.rs:16:13
+  --> $DIR/type-checking-test-1.rs:19:13
    |
 LL |     let _ = x as &dyn Bar<_>; // Ambiguous
    |             ^ the trait `Bar<_>` is not implemented for `&dyn Foo`
diff --git a/tests/ui/traits/trait-upcasting/type-checking-test-1.next.stderr b/tests/ui/traits/trait-upcasting/type-checking-test-1.next.stderr
new file mode 100644
index 0000000000000..b612005fcb051
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/type-checking-test-1.next.stderr
@@ -0,0 +1,9 @@
+error[E0605]: non-primitive cast: `&dyn Foo` as `&dyn Bar<_>`
+  --> $DIR/type-checking-test-1.rs:19:13
+   |
+LL |     let _ = x as &dyn Bar<_>; // Ambiguous
+   |             ^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0605`.
diff --git a/tests/ui/traits/trait-upcasting/type-checking-test-1.rs b/tests/ui/traits/trait-upcasting/type-checking-test-1.rs
index 6bc9f4a75d333..7c7beec0809d7 100644
--- a/tests/ui/traits/trait-upcasting/type-checking-test-1.rs
+++ b/tests/ui/traits/trait-upcasting/type-checking-test-1.rs
@@ -1,3 +1,6 @@
+// revisions: current next
+//[next] compile-flags: -Ztrait-solver=next
+
 #![feature(trait_upcasting)]
 
 trait Foo: Bar<i32> + Bar<u32> {}
@@ -15,7 +18,7 @@ fn test_specific(x: &dyn Foo) {
 fn test_unknown_version(x: &dyn Foo) {
     let _ = x as &dyn Bar<_>; // Ambiguous
                               //~^ ERROR non-primitive cast
-                              //~^^ ERROR the trait bound `&dyn Foo: Bar<_>` is not satisfied
+                              //[current]~^^ ERROR the trait bound `&dyn Foo: Bar<_>` is not satisfied
 }
 
 fn test_infer_version(x: &dyn Foo) {
diff --git a/tests/ui/unsized/issue-75899.rs b/tests/ui/unsized/issue-75899.rs
index abff17e11b54a..7194310329157 100644
--- a/tests/ui/unsized/issue-75899.rs
+++ b/tests/ui/unsized/issue-75899.rs
@@ -1,3 +1,5 @@
+// revisions: current next
+//[next] compile-flags: -Ztrait-solver=next
 // check-pass
 
 trait Trait {}
diff --git a/tests/ui/where-clauses/where-clause-bounds-inconsistency.rs b/tests/ui/where-clauses/where-clause-bounds-inconsistency.rs
index cf7d06b6179b0..ea60fa708764f 100644
--- a/tests/ui/where-clauses/where-clause-bounds-inconsistency.rs
+++ b/tests/ui/where-clauses/where-clause-bounds-inconsistency.rs
@@ -14,7 +14,6 @@ trait Trait {
 
 impl Trait for bool {
     fn a<T: Bound>(&self, _: T) {}
-    //^~ This gets rejected but should be accepted
     fn b<T>(&self, _: T) where T: Bound {}
     fn c<T: Bound>(&self, _: T) {}
     fn d<T>(&self, _: T) where T: Bound {}