diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index aea47c9e987..a17c007debd 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -32,6 +32,7 @@
 #![feature(unwrap_infallible)]
 #![feature(yeet_expr)]
 #![recursion_limit = "512"] // For rustdoc
+#![warn(unreachable_pub)] // For rustdoc
 // tidy-alphabetical-end
 
 pub mod error_reporting;
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index bf4b0482081..8ff803657f0 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -54,7 +54,7 @@ pub fn add_placeholder_note<G: EmissionGuarantee>(err: &mut Diag<'_, G>) {
     );
 }
 
-pub fn suggest_increasing_recursion_limit<'tcx, G: EmissionGuarantee>(
+pub(crate) fn suggest_increasing_recursion_limit<'tcx, G: EmissionGuarantee>(
     tcx: TyCtxt<'tcx>,
     err: &mut Diag<'_, G>,
     overflowing_predicates: &[ty::Predicate<'tcx>],
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index fa696dcd2f5..a3d5c530797 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -29,8 +29,8 @@ use tracing::{debug, instrument};
 use super::elaborate;
 use crate::infer::TyCtxtInferExt;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
-use crate::traits::{util, Obligation, ObligationCause};
-pub use crate::traits::{MethodViolationCode, ObjectSafetyViolation};
+pub use crate::traits::ObjectSafetyViolation;
+use crate::traits::{util, MethodViolationCode, Obligation, ObligationCause};
 
 /// Returns the object safety violations that affect HIR ty lowering.
 ///
@@ -512,7 +512,7 @@ fn virtual_call_violations_for_method<'tcx>(
 ///
 /// This check is outlined from the object safety check to avoid cycles with
 /// layout computation, which relies on knowing whether methods are object safe.
-pub fn check_receiver_correct<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, method: ty::AssocItem) {
+fn check_receiver_correct<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, method: ty::AssocItem) {
     if !is_vtable_safe_method(tcx, trait_def_id, method) {
         return;
     }
@@ -906,7 +906,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for EraseEscapingBoundRegions<'tcx> {
     }
 }
 
-pub fn contains_illegal_impl_trait_in_trait<'tcx>(
+fn contains_illegal_impl_trait_in_trait<'tcx>(
     tcx: TyCtxt<'tcx>,
     fn_def_id: DefId,
     ty: ty::Binder<'tcx, Ty<'tcx>>,
@@ -930,7 +930,7 @@ pub fn contains_illegal_impl_trait_in_trait<'tcx>(
     })
 }
 
-pub fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers {
         object_safety_violations,
         is_object_safe,
diff --git a/compiler/rustc_trait_selection/src/traits/select/_match.rs b/compiler/rustc_trait_selection/src/traits/select/_match.rs
index 7ead65721f9..f77f83ed447 100644
--- a/compiler/rustc_trait_selection/src/traits/select/_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/_match.rs
@@ -21,12 +21,12 @@ use tracing::instrument;
 /// Like subtyping, matching is really a binary relation, so the only
 /// important thing about the result is Ok/Err. Also, matching never
 /// affects any type variables or unification state.
-pub struct MatchAgainstFreshVars<'tcx> {
+pub(crate) struct MatchAgainstFreshVars<'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
 impl<'tcx> MatchAgainstFreshVars<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>) -> MatchAgainstFreshVars<'tcx> {
+    pub(crate) fn new(tcx: TyCtxt<'tcx>) -> MatchAgainstFreshVars<'tcx> {
         MatchAgainstFreshVars { tcx }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 91fe19c20f7..bc4a3398f9b 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -3127,7 +3127,7 @@ impl<'o, 'tcx> fmt::Debug for TraitObligationStack<'o, 'tcx> {
     }
 }
 
-pub enum ProjectionMatchesProjection {
+pub(crate) enum ProjectionMatchesProjection {
     Yes,
     Ambiguous,
     No,
diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs
index 0689b880f33..0fb13799e67 100644
--- a/compiler/rustc_trait_selection/src/traits/util.rs
+++ b/compiler/rustc_trait_selection/src/traits/util.rs
@@ -169,7 +169,7 @@ impl<'tcx> Iterator for TraitAliasExpander<'tcx> {
 /// Instantiate all bound parameters of the impl subject with the given args,
 /// returning the resulting subject and all obligations that arise.
 /// The obligations are closed under normalization.
-pub fn impl_subject_and_oblig<'a, 'tcx>(
+pub(crate) fn impl_subject_and_oblig<'a, 'tcx>(
     selcx: &SelectionContext<'a, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     impl_def_id: DefId,
@@ -209,7 +209,7 @@ pub fn upcast_choices<'tcx>(
     supertraits(tcx, source_trait_ref).filter(|r| r.def_id() == target_trait_def_id).collect()
 }
 
-pub fn closure_trait_ref_and_return_type<'tcx>(
+pub(crate) fn closure_trait_ref_and_return_type<'tcx>(
     tcx: TyCtxt<'tcx>,
     fn_trait_def_id: DefId,
     self_ty: Ty<'tcx>,
@@ -238,7 +238,7 @@ pub fn closure_trait_ref_and_return_type<'tcx>(
     sig.map_bound(|sig| (trait_ref, sig.output()))
 }
 
-pub fn coroutine_trait_ref_and_outputs<'tcx>(
+pub(crate) fn coroutine_trait_ref_and_outputs<'tcx>(
     tcx: TyCtxt<'tcx>,
     fn_trait_def_id: DefId,
     self_ty: Ty<'tcx>,
@@ -249,7 +249,7 @@ pub fn coroutine_trait_ref_and_outputs<'tcx>(
     (trait_ref, sig.yield_ty, sig.return_ty)
 }
 
-pub fn future_trait_ref_and_outputs<'tcx>(
+pub(crate) fn future_trait_ref_and_outputs<'tcx>(
     tcx: TyCtxt<'tcx>,
     fn_trait_def_id: DefId,
     self_ty: Ty<'tcx>,
@@ -260,7 +260,7 @@ pub fn future_trait_ref_and_outputs<'tcx>(
     (trait_ref, sig.return_ty)
 }
 
-pub fn iterator_trait_ref_and_outputs<'tcx>(
+pub(crate) fn iterator_trait_ref_and_outputs<'tcx>(
     tcx: TyCtxt<'tcx>,
     iterator_def_id: DefId,
     self_ty: Ty<'tcx>,
@@ -271,7 +271,7 @@ pub fn iterator_trait_ref_and_outputs<'tcx>(
     (trait_ref, sig.yield_ty)
 }
 
-pub fn async_iterator_trait_ref_and_outputs<'tcx>(
+pub(crate) fn async_iterator_trait_ref_and_outputs<'tcx>(
     tcx: TyCtxt<'tcx>,
     async_iterator_def_id: DefId,
     self_ty: Ty<'tcx>,
@@ -287,7 +287,7 @@ pub fn impl_item_is_final(tcx: TyCtxt<'_>, assoc_item: &ty::AssocItem) -> bool {
         && tcx.defaultness(assoc_item.container_id(tcx)).is_final()
 }
 
-pub enum TupleArgumentsFlag {
+pub(crate) enum TupleArgumentsFlag {
     Yes,
     No,
 }