diff --git a/crates/fayalite/src/intern.rs b/crates/fayalite/src/intern.rs
index 97dafe1..29337d7 100644
--- a/crates/fayalite/src/intern.rs
+++ b/crates/fayalite/src/intern.rs
@@ -16,9 +16,10 @@ use std::{
     marker::PhantomData,
     ops::Deref,
     path::{Path, PathBuf},
-    sync::{Mutex, RwLock},
+    sync::RwLock,
 };
 
+mod interner;
 mod type_map;
 
 pub trait LazyInternedTrait<T: ?Sized + Send + Sync + 'static>: Send + Sync + Any {
@@ -593,78 +594,6 @@ impl<T: ?Sized + 'static + Send + Sync + ToOwned> From<Interned<T>> for Cow<'_,
     }
 }
 
-struct InternerState<T: ?Sized + 'static + Send + Sync> {
-    table: HashTable<&'static T>,
-    hasher: DefaultBuildHasher,
-}
-
-pub(crate) struct Interner<T: ?Sized + 'static + Send + Sync> {
-    state: Mutex<InternerState<T>>,
-}
-
-impl<T: ?Sized + 'static + Send + Sync> Interner<T> {
-    fn get() -> &'static Interner<T> {
-        static TYPE_ID_MAP: TypeIdMap = TypeIdMap::new();
-        thread_local! {
-            static TYPE_ID_MAP_CACHE: TypeIdMap = const { TypeIdMap::new() };
-        }
-        TYPE_ID_MAP_CACHE.with(|cache| {
-            cache.get_or_insert_with(|| {
-                TYPE_ID_MAP.get_or_insert_with(|| Box::leak(Default::default()))
-            })
-        })
-    }
-}
-
-impl<T: ?Sized + 'static + Send + Sync> Default for Interner<T> {
-    fn default() -> Self {
-        Self {
-            state: Mutex::new(InternerState {
-                table: HashTable::new(),
-                hasher: Default::default(),
-            }),
-        }
-    }
-}
-
-impl<T: ?Sized + 'static + Send + Sync + Hash + Eq + ToOwned> Interner<T> {
-    fn intern<F: FnOnce(Cow<'_, T>) -> &'static T>(
-        &self,
-        alloc: F,
-        value: Cow<'_, T>,
-    ) -> Interned<T> {
-        let mut state = self.state.lock().unwrap();
-        let InternerState { table, hasher } = &mut *state;
-        let inner = *table
-            .entry(
-                hasher.hash_one(&*value),
-                |k| **k == *value,
-                |k| hasher.hash_one(&**k),
-            )
-            .or_insert_with(|| alloc(value))
-            .get();
-        Interned { inner }
-    }
-}
-
-impl<T: Clone + 'static + Send + Sync + Hash + Eq> Interner<T> {
-    fn intern_sized(&self, value: Cow<'_, T>) -> Interned<T> {
-        self.intern(|value| Box::leak(Box::new(value.into_owned())), value)
-    }
-}
-
-impl<T: Clone + 'static + Send + Sync + Hash + Eq> Interner<[T]> {
-    fn intern_slice(&self, value: Cow<'_, [T]>) -> Interned<[T]> {
-        self.intern(|value| value.into_owned().leak(), value)
-    }
-}
-
-impl Interner<BitSlice> {
-    fn intern_bit_slice(&self, value: Cow<'_, BitSlice>) -> Interned<BitSlice> {
-        self.intern(|value| value.into_owned().leak(), value)
-    }
-}
-
 pub struct Interned<T: ?Sized + 'static + Send + Sync> {
     inner: &'static T,
 }
@@ -984,7 +913,7 @@ impl<T: Clone + Send + Sync + 'static + Hash + Eq> Intern for T {
     where
         Self: ToOwned,
     {
-        Interner::get().intern_sized(this)
+        interner::Interner::get().intern_sized(this)
     }
 }
 
@@ -1004,7 +933,7 @@ impl<T: Clone + Send + Sync + 'static + Hash + Eq> Intern for [T] {
     where
         Self: ToOwned,
     {
-        Interner::get().intern_slice(this)
+        interner::Interner::get().intern_slice(this)
     }
 }
 
@@ -1024,7 +953,7 @@ impl Intern for BitSlice {
     where
         Self: ToOwned,
     {
-        Interner::get().intern_bit_slice(this)
+        interner::Interner::get().intern_bit_slice(this)
     }
 }
 
diff --git a/crates/fayalite/src/intern/interner.rs b/crates/fayalite/src/intern/interner.rs
new file mode 100644
index 0000000..45899af
--- /dev/null
+++ b/crates/fayalite/src/intern/interner.rs
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use crate::{
+    intern::{Interned, type_map::TypeIdMap},
+    util::DefaultBuildHasher,
+};
+use bitvec::slice::BitSlice;
+use hashbrown::HashTable;
+use std::{
+    borrow::Cow,
+    hash::{BuildHasher, Hash},
+    sync::Mutex,
+};
+
+struct InternerState<T: ?Sized + 'static + Send + Sync> {
+    table: HashTable<&'static T>,
+    hasher: DefaultBuildHasher,
+}
+
+pub(crate) struct Interner<T: ?Sized + 'static + Send + Sync> {
+    state: Mutex<InternerState<T>>,
+}
+
+impl<T: ?Sized + 'static + Send + Sync> Interner<T> {
+    pub(crate) fn get() -> &'static Interner<T> {
+        static TYPE_ID_MAP: TypeIdMap = TypeIdMap::new();
+        thread_local! {
+            static TYPE_ID_MAP_CACHE: TypeIdMap = const { TypeIdMap::new() };
+        }
+        TYPE_ID_MAP_CACHE.with(|cache| {
+            cache.get_or_insert_with(|| {
+                TYPE_ID_MAP.get_or_insert_with(|| Box::leak(Default::default()))
+            })
+        })
+    }
+}
+
+impl<T: ?Sized + 'static + Send + Sync> Default for Interner<T> {
+    fn default() -> Self {
+        Self {
+            state: Mutex::new(InternerState {
+                table: HashTable::new(),
+                hasher: Default::default(),
+            }),
+        }
+    }
+}
+
+impl<T: ?Sized + 'static + Send + Sync + Hash + Eq + ToOwned> Interner<T> {
+    fn intern<F: FnOnce(Cow<'_, T>) -> &'static T>(
+        &self,
+        alloc: F,
+        value: Cow<'_, T>,
+    ) -> Interned<T> {
+        let mut state = self.state.lock().unwrap();
+        let InternerState { table, hasher } = &mut *state;
+        let inner = *table
+            .entry(
+                hasher.hash_one(&*value),
+                |k| **k == *value,
+                |k| hasher.hash_one(&**k),
+            )
+            .or_insert_with(|| alloc(value))
+            .get();
+        Interned { inner }
+    }
+}
+
+impl<T: Clone + 'static + Send + Sync + Hash + Eq> Interner<T> {
+    pub(crate) fn intern_sized(&self, value: Cow<'_, T>) -> Interned<T> {
+        self.intern(|value| Box::leak(Box::new(value.into_owned())), value)
+    }
+}
+
+impl<T: Clone + 'static + Send + Sync + Hash + Eq> Interner<[T]> {
+    pub(crate) fn intern_slice(&self, value: Cow<'_, [T]>) -> Interned<[T]> {
+        self.intern(|value| value.into_owned().leak(), value)
+    }
+}
+
+impl Interner<BitSlice> {
+    pub(crate) fn intern_bit_slice(&self, value: Cow<'_, BitSlice>) -> Interned<BitSlice> {
+        self.intern(|value| value.into_owned().leak(), value)
+    }
+}