diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9ebce784..2a52f39d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,8 +25,6 @@ jobs:
             features: quickcheck
           - rust: stable
             features: rayon
-          - rust: stable
-            features: rustc-rayon
           - rust: stable
             features: serde
           - rust: stable
diff --git a/Cargo.toml b/Cargo.toml
index e85e6f60..8850a6fd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,10 +22,6 @@ serde = { version = "1.0", optional = true, default-features = false }
 borsh = { version = "1.2", optional = true, default-features = false }
 rayon = { version = "1.9", optional = true }
 
-# Internal feature, only used when building as part of rustc,
-# not part of the stable interface of this crate.
-rustc-rayon = { package = "rustc-rayon", version = "0.5", optional = true }
-
 [dependencies.hashbrown]
 version = "0.15.0"
 default-features = false
diff --git a/src/lib.rs b/src/lib.rs
index 4fd9aac1..e99f0a22 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -127,9 +127,6 @@ pub mod set;
 #[cfg(feature = "rayon")]
 mod rayon;
 
-#[cfg(feature = "rustc-rayon")]
-mod rustc;
-
 pub use crate::map::IndexMap;
 pub use crate::set::IndexSet;
 pub use equivalent::Equivalent;
diff --git a/src/macros.rs b/src/macros.rs
index b347de22..65f34369 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -125,7 +125,7 @@ macro_rules! double_ended_iterator_methods {
 
 // generate `ParallelIterator` methods by just forwarding to the underlying
 // self.entries and mapping its elements.
-#[cfg(any(feature = "rayon", feature = "rustc-rayon"))]
+#[cfg(feature = "rayon")]
 macro_rules! parallel_iterator_methods {
     // $map_elt is the mapping function from the underlying iterator's element
     ($map_elt:expr) => {
@@ -150,7 +150,7 @@ macro_rules! parallel_iterator_methods {
 
 // generate `IndexedParallelIterator` methods by just forwarding to the underlying
 // self.entries and mapping its elements.
-#[cfg(any(feature = "rayon", feature = "rustc-rayon"))]
+#[cfg(feature = "rayon")]
 macro_rules! indexed_parallel_iterator_methods {
     // $map_elt is the mapping function from the underlying iterator's element
     ($map_elt:expr) => {
diff --git a/src/rustc.rs b/src/rustc.rs
deleted file mode 100644
index b843858b..00000000
--- a/src/rustc.rs
+++ /dev/null
@@ -1,158 +0,0 @@
-//! Minimal support for `rustc-rayon`, not intended for general use.
-
-use crate::vec::Vec;
-use crate::{Bucket, Entries, IndexMap, IndexSet};
-
-use rustc_rayon::iter::plumbing::{Consumer, ProducerCallback, UnindexedConsumer};
-use rustc_rayon::iter::{IndexedParallelIterator, IntoParallelIterator, ParallelIterator};
-
-mod map {
-    use super::*;
-
-    impl<K, V, S> IntoParallelIterator for IndexMap<K, V, S>
-    where
-        K: Send,
-        V: Send,
-    {
-        type Item = (K, V);
-        type Iter = IntoParIter<K, V>;
-
-        fn into_par_iter(self) -> Self::Iter {
-            IntoParIter {
-                entries: self.into_entries(),
-            }
-        }
-    }
-
-    pub struct IntoParIter<K, V> {
-        entries: Vec<Bucket<K, V>>,
-    }
-
-    impl<K: Send, V: Send> ParallelIterator for IntoParIter<K, V> {
-        type Item = (K, V);
-
-        parallel_iterator_methods!(Bucket::key_value);
-    }
-
-    impl<K: Send, V: Send> IndexedParallelIterator for IntoParIter<K, V> {
-        indexed_parallel_iterator_methods!(Bucket::key_value);
-    }
-
-    impl<'a, K, V, S> IntoParallelIterator for &'a IndexMap<K, V, S>
-    where
-        K: Sync,
-        V: Sync,
-    {
-        type Item = (&'a K, &'a V);
-        type Iter = ParIter<'a, K, V>;
-
-        fn into_par_iter(self) -> Self::Iter {
-            ParIter {
-                entries: self.as_entries(),
-            }
-        }
-    }
-
-    pub struct ParIter<'a, K, V> {
-        entries: &'a [Bucket<K, V>],
-    }
-
-    impl<'a, K: Sync, V: Sync> ParallelIterator for ParIter<'a, K, V> {
-        type Item = (&'a K, &'a V);
-
-        parallel_iterator_methods!(Bucket::refs);
-    }
-
-    impl<K: Sync, V: Sync> IndexedParallelIterator for ParIter<'_, K, V> {
-        indexed_parallel_iterator_methods!(Bucket::refs);
-    }
-
-    impl<'a, K, V, S> IntoParallelIterator for &'a mut IndexMap<K, V, S>
-    where
-        K: Sync + Send,
-        V: Send,
-    {
-        type Item = (&'a K, &'a mut V);
-        type Iter = ParIterMut<'a, K, V>;
-
-        fn into_par_iter(self) -> Self::Iter {
-            ParIterMut {
-                entries: self.as_entries_mut(),
-            }
-        }
-    }
-
-    pub struct ParIterMut<'a, K, V> {
-        entries: &'a mut [Bucket<K, V>],
-    }
-
-    impl<'a, K: Sync + Send, V: Send> ParallelIterator for ParIterMut<'a, K, V> {
-        type Item = (&'a K, &'a mut V);
-
-        parallel_iterator_methods!(Bucket::ref_mut);
-    }
-
-    impl<K: Sync + Send, V: Send> IndexedParallelIterator for ParIterMut<'_, K, V> {
-        indexed_parallel_iterator_methods!(Bucket::ref_mut);
-    }
-}
-
-mod set {
-    use super::*;
-
-    impl<T, S> IntoParallelIterator for IndexSet<T, S>
-    where
-        T: Send,
-    {
-        type Item = T;
-        type Iter = IntoParIter<T>;
-
-        fn into_par_iter(self) -> Self::Iter {
-            IntoParIter {
-                entries: self.into_entries(),
-            }
-        }
-    }
-
-    pub struct IntoParIter<T> {
-        entries: Vec<Bucket<T, ()>>,
-    }
-
-    impl<T: Send> ParallelIterator for IntoParIter<T> {
-        type Item = T;
-
-        parallel_iterator_methods!(Bucket::key);
-    }
-
-    impl<T: Send> IndexedParallelIterator for IntoParIter<T> {
-        indexed_parallel_iterator_methods!(Bucket::key);
-    }
-
-    impl<'a, T, S> IntoParallelIterator for &'a IndexSet<T, S>
-    where
-        T: Sync,
-    {
-        type Item = &'a T;
-        type Iter = ParIter<'a, T>;
-
-        fn into_par_iter(self) -> Self::Iter {
-            ParIter {
-                entries: self.as_entries(),
-            }
-        }
-    }
-
-    pub struct ParIter<'a, T> {
-        entries: &'a [Bucket<T, ()>],
-    }
-
-    impl<'a, T: Sync> ParallelIterator for ParIter<'a, T> {
-        type Item = &'a T;
-
-        parallel_iterator_methods!(Bucket::key_ref);
-    }
-
-    impl<T: Sync> IndexedParallelIterator for ParIter<'_, T> {
-        indexed_parallel_iterator_methods!(Bucket::key_ref);
-    }
-}