diff --git a/compiler/rustc_smir/src/lib.rs b/compiler/rustc_smir/src/lib.rs
index 9f88887530614..2215e2f01ade0 100644
--- a/compiler/rustc_smir/src/lib.rs
+++ b/compiler/rustc_smir/src/lib.rs
@@ -15,6 +15,7 @@
 )]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod rustc_internal;
diff --git a/compiler/rustc_smir/src/rustc_smir/alloc.rs b/compiler/rustc_smir/src/rustc_smir/alloc.rs
index 677b4c7a9c0e3..11fbc005e37da 100644
--- a/compiler/rustc_smir/src/rustc_smir/alloc.rs
+++ b/compiler/rustc_smir/src/rustc_smir/alloc.rs
@@ -20,7 +20,7 @@ fn new_empty_allocation(align: rustc_target::abi::Align) -> Allocation {
 // because we need to get `Ty` of the const we are trying to create, to do that
 // we need to have access to `ConstantKind` but we can't access that inside Stable impl.
 #[allow(rustc::usage_of_qualified_ty)]
-pub fn new_allocation<'tcx>(
+pub(crate) fn new_allocation<'tcx>(
     ty: rustc_middle::ty::Ty<'tcx>,
     const_value: ConstValue<'tcx>,
     tables: &mut Tables<'tcx>,
@@ -30,7 +30,7 @@ pub fn new_allocation<'tcx>(
 }
 
 #[allow(rustc::usage_of_qualified_ty)]
-pub fn try_new_allocation<'tcx>(
+pub(crate) fn try_new_allocation<'tcx>(
     ty: rustc_middle::ty::Ty<'tcx>,
     const_value: ConstValue<'tcx>,
     tables: &mut Tables<'tcx>,
diff --git a/compiler/rustc_smir/src/rustc_smir/builder.rs b/compiler/rustc_smir/src/rustc_smir/builder.rs
index 883ab7c18b485..cd91fc26c1018 100644
--- a/compiler/rustc_smir/src/rustc_smir/builder.rs
+++ b/compiler/rustc_smir/src/rustc_smir/builder.rs
@@ -12,13 +12,13 @@ use rustc_middle::ty::{self, TyCtxt};
 use crate::rustc_smir::{Stable, Tables};
 
 /// Builds a monomorphic body for a given instance.
-pub struct BodyBuilder<'tcx> {
+pub(crate) struct BodyBuilder<'tcx> {
     tcx: TyCtxt<'tcx>,
     instance: ty::Instance<'tcx>,
 }
 
 impl<'tcx> BodyBuilder<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>, instance: ty::Instance<'tcx>) -> Self {
+    pub(crate) fn new(tcx: TyCtxt<'tcx>, instance: ty::Instance<'tcx>) -> Self {
         let instance = match instance.def {
             // To get the fallback body of an intrinsic, we need to convert it to an item.
             ty::InstanceKind::Intrinsic(def_id) => ty::Instance::new(def_id, instance.args),
@@ -30,7 +30,7 @@ impl<'tcx> BodyBuilder<'tcx> {
     /// Build a stable monomorphic body for a given instance based on the MIR body.
     ///
     /// All constants are also evaluated.
-    pub fn build(mut self, tables: &mut Tables<'tcx>) -> stable_mir::mir::Body {
+    pub(crate) fn build(mut self, tables: &mut Tables<'tcx>) -> stable_mir::mir::Body {
         let body = tables.tcx.instance_mir(self.instance.def).clone();
         let mono_body = if !self.instance.args.is_empty()
             // Without the `generic_const_exprs` feature gate, anon consts in signatures do not
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index f9663f2dd30d9..a4ede374a19dc 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -784,7 +784,7 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
     }
 }
 
-pub struct TablesWrapper<'tcx>(pub RefCell<Tables<'tcx>>);
+pub(crate) struct TablesWrapper<'tcx>(pub RefCell<Tables<'tcx>>);
 
 /// Implement error handling for extracting function ABI information.
 impl<'tcx> FnAbiOfHelpers<'tcx> for Tables<'tcx> {
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/mod.rs b/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
index 50687935473a7..c9795fca3993a 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
@@ -9,7 +9,7 @@ mod error;
 mod mir;
 mod ty;
 
-pub use ty::mir_const_from_ty_const;
+pub(crate) use ty::mir_const_from_ty_const;
 
 impl<'tcx> Stable<'tcx> for rustc_hir::Safety {
     type T = stable_mir::mir::Safety;
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
index 9afd732486c28..efbb0f244fc8f 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
@@ -411,7 +411,7 @@ impl<'tcx> Stable<'tcx> for ty::Pattern<'tcx> {
     }
 }
 
-pub fn mir_const_from_ty_const<'tcx>(
+pub(crate) fn mir_const_from_ty_const<'tcx>(
     tables: &mut Tables<'tcx>,
     ty_const: ty::Const<'tcx>,
     ty: Ty<'tcx>,