diff --git a/Cargo.toml b/Cargo.toml
index e412ba0..9cf231d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "skl"
-version = "0.22.7"
+version = "0.22.8"
 edition = "2021"
 rust-version = "1.81.0"
 repository = "https://github.com/al8n/skl"
diff --git a/src/dynamic.rs b/src/dynamic.rs
index 3ed234f..aef3ca1 100644
--- a/src/dynamic.rs
+++ b/src/dynamic.rs
@@ -19,10 +19,6 @@ pub mod entry {
   pub use super::list::EntryRef;
 }
 
-pub use dbutils::equivalentor::{BytesComparator, BytesEquivalentor, BytesRangeComparator};
-
-/// Ascend is a comparator that compares byte slices in ascending order.
-pub type Ascend = dbutils::equivalentor::Ascend<[u8]>;
-
-/// Ascend is a comparator that compares byte slices in ascending order.
-pub type Descend = dbutils::equivalentor::Descend<[u8]>;
+pub use dbutils::equivalentor::{
+  Ascend, BytesComparator, BytesEquivalentor, BytesRangeComparator, Descend,
+};
diff --git a/src/dynamic/builder.rs b/src/dynamic/builder.rs
index e1175c8..30d9303 100644
--- a/src/dynamic/builder.rs
+++ b/src/dynamic/builder.rs
@@ -17,7 +17,7 @@ mod memmap;
 
 /// A builder for creating a dynamic key-value `SkipMap`.
 #[derive(Debug, Clone)]
-pub struct Builder<C = Ascend<[u8]>> {
+pub struct Builder<C = Ascend> {
   options: Options,
   cmp: C,
 }
diff --git a/src/dynamic/list.rs b/src/dynamic/list.rs
index f9516b5..ca6c363 100644
--- a/src/dynamic/list.rs
+++ b/src/dynamic/list.rs
@@ -35,7 +35,7 @@ type UpdateOk<'a, 'b, A, RC, C> = Either<
 /// A fast, cocnurrent map implementation based on skiplist that supports forward
 /// and backward iteration.
 #[derive(Debug)]
-pub struct SkipList<A, R, C = Ascend<[u8]>>
+pub struct SkipList<A, R, C = Ascend>
 where
   A: Allocator,
   R: RefCounter,
diff --git a/src/dynamic/multiple_version.rs b/src/dynamic/multiple_version.rs
index f8ac1b1..9535fde 100644
--- a/src/dynamic/multiple_version.rs
+++ b/src/dynamic/multiple_version.rs
@@ -48,7 +48,7 @@ pub mod unsync {
   ///
   /// If you want to use in concurrent environment, you can use [`multiple_version::sync::SkipMap`](crate::dynamic::multiple_version::sync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<C = Ascend<[u8]>>(SkipList<C>);
+  pub struct SkipMap<C = Ascend>(SkipList<C>);
 
   impl<C: Clone> Clone for SkipMap<C> {
     #[inline]
@@ -145,7 +145,7 @@ pub mod sync {
   ///
   /// If you want to use in non-concurrent environment, you can use [`multiple_version::unsync::SkipMap`](crate::dynamic::multiple_version::unsync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<C = Ascend<[u8]>>(SkipList<C>);
+  pub struct SkipMap<C = Ascend>(SkipList<C>);
 
   impl<C: Clone> Clone for SkipMap<C> {
     #[inline]
diff --git a/src/dynamic/unique.rs b/src/dynamic/unique.rs
index 30b2a49..df2a0a8 100644
--- a/src/dynamic/unique.rs
+++ b/src/dynamic/unique.rs
@@ -48,7 +48,7 @@ pub mod unsync {
   ///
   /// If you want to use in concurrent environment, you can use [`unique::sync::SkipMap`](crate::dynamic::unique::sync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<C = Ascend<[u8]>>(SkipList<C>);
+  pub struct SkipMap<C = Ascend>(SkipList<C>);
 
   impl<C: Clone> Clone for SkipMap<C> {
     #[inline]
@@ -143,7 +143,7 @@ pub mod sync {
   ///
   /// If you want to use in non-concurrent environment, you can use [`unique::unsync::SkipMap`](crate::dynamic::unique::unsync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<C = Ascend<[u8]>>(SkipList<C>);
+  pub struct SkipMap<C = Ascend>(SkipList<C>);
 
   impl<C: Clone> Clone for SkipMap<C> {
     #[inline]
diff --git a/src/generic/builder.rs b/src/generic/builder.rs
index d5b28de..9a0f7ea 100644
--- a/src/generic/builder.rs
+++ b/src/generic/builder.rs
@@ -16,7 +16,7 @@ mod memmap;
 
 /// A builder for creating a generic key-value `SkipMap`.
 #[derive(Debug)]
-pub struct Builder<C = Ascend<[u8]>> {
+pub struct Builder<C = Ascend> {
   options: Options,
   cmp: C,
 }
@@ -57,9 +57,9 @@ impl<C> Builder<C> {
   /// ## Example
   ///
   /// ```rust
-  /// use skl::generic::{Builder, Ascend};
+  /// use skl::generic::{Builder, Descend};
   ///
-  /// let builder = Builder::with(Ascend::<[u8]>::new());
+  /// let builder = Builder::with(Descend::new());
   /// ```
   #[inline]
   pub const fn with(cmp: C) -> Self {
@@ -78,7 +78,7 @@ impl<C: Default> Builder<C> {
   /// ```rust
   /// use skl::generic::{Builder, Ascend};
   ///
-  /// let builder = Builder::<Ascend<str>>::new();
+  /// let builder = Builder::<Ascend>::new();
   /// ```
   #[inline]
   pub fn new() -> Self {
@@ -97,7 +97,7 @@ impl<C> Builder<C> {
   /// ```rust
   /// use skl::generic::{Builder, Ascend};
   ///
-  /// let builder = Builder::<Ascend<str>>::new().comparator();
+  /// let builder = Builder::<Ascend>::new().comparator();
   /// ```
   #[inline]
   pub const fn comparator(&self) -> &C {
@@ -109,11 +109,11 @@ impl<C> Builder<C> {
   /// ## Example
   ///
   /// ```rust
-  /// use skl::generic::{Builder, Ascend};
+  /// use skl::generic::{Builder, Ascend, Descend};
   ///
-  /// let builder = Builder::<Ascend<[u8]>>::new().with_comparator(Ascend::<Vec<u8>>::new());
+  /// let builder = Builder::<Ascend>::new().with_comparator(Descend::new());
   ///
-  /// assert_eq!(builder.comparator(), &Ascend::<Vec<u8>>::new());
+  /// assert_eq!(builder.comparator(), &Descend::new());
   /// ```
   #[inline]
   pub fn with_comparator<NC>(self, cmp: NC) -> Builder<NC> {
@@ -128,9 +128,9 @@ impl<C> Builder<C> {
   /// ## Example
   ///
   /// ```rust
-  /// use skl::generic::{Builder, Ascend};
+  /// use skl::generic::{Builder, Descend};
   ///
-  /// let builder = Builder::<Ascend<str>>::new();
+  /// let builder = Builder::<Descend>::new();
   /// let options = builder.options();
   /// ```
   #[inline]
@@ -179,9 +179,9 @@ impl<C> Builder<C> {
   /// ```rust
   /// use skl::generic::{unique::sync, multiple_version::unsync, Builder, Ascend};
   ///
-  /// let map = Builder::<Ascend<[u8]>>::new().with_capacity(1024).alloc::<sync::SkipMap<[u8], [u8]>>().unwrap();
+  /// let map = Builder::<Ascend>::new().with_capacity(1024).alloc::<sync::SkipMap<[u8], [u8]>>().unwrap();
   ///
-  /// let arena = Builder::<Ascend<[u8]>>::new().with_capacity(1024).alloc::<unsync::SkipMap<[u8], [u8]>>().unwrap();
+  /// let arena = Builder::<Ascend>::new().with_capacity(1024).alloc::<unsync::SkipMap<[u8], [u8]>>().unwrap();
   /// ```
   #[inline]
   pub fn alloc<T>(self) -> Result<T, Error>
diff --git a/src/generic/builder/memmap.rs b/src/generic/builder/memmap.rs
index c2c9080..101f62c 100644
--- a/src/generic/builder/memmap.rs
+++ b/src/generic/builder/memmap.rs
@@ -31,9 +31,9 @@ impl<C> Builder<C> {
   /// ```rust
   /// use skl::generic::{unique::sync, multiple_version::unsync, Builder, Ascend};
   ///
-  /// let map = Builder::<Ascend<[u8]>>::new().with_capacity(1024).map_anon::<sync::SkipMap<[u8], [u8]>>().unwrap();
+  /// let map = Builder::<Ascend>::new().with_capacity(1024).map_anon::<sync::SkipMap<[u8], [u8]>>().unwrap();
   ///
-  /// let arena = Builder::<Ascend<[u8]>>::new().with_capacity(1024).map_anon::<unsync::SkipMap<[u8], [u8]>>().unwrap();
+  /// let arena = Builder::<Ascend>::new().with_capacity(1024).map_anon::<unsync::SkipMap<[u8], [u8]>>().unwrap();
   /// ```
   #[cfg(all(feature = "memmap", not(target_family = "wasm")))]
   #[cfg_attr(docsrs, doc(cfg(all(feature = "memmap", not(target_family = "wasm")))))]
diff --git a/src/generic/list.rs b/src/generic/list.rs
index c53910c..b7674f1 100644
--- a/src/generic/list.rs
+++ b/src/generic/list.rs
@@ -562,7 +562,7 @@ where
   ) -> (Option<<A::Node as Node>::Pointer>, bool)
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     let mut x = self.head;
     let mut level = self.meta().height() as usize - 1;
@@ -662,7 +662,7 @@ where
     returned_when_found: bool,
   ) -> (bool, Option<Pointer>, Option<<A::Node as Node>::Pointer>)
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let list_height = self.meta().height() as u32;
     let mut level = 0;
@@ -741,7 +741,7 @@ where
     start: <A::Node as Node>::Pointer,
   ) -> FindResult<<A::Node as Node>::Pointer>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let mut prev = start;
 
@@ -847,7 +847,7 @@ where
     key: Among<&'a [u8], &'b [u8], &'b K>,
   ) -> bool
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let nd_key = self
       .arena
@@ -909,7 +909,7 @@ where
     upsert: bool,
   ) -> Result<UpdateOk<'a, 'b, K, V, A, R, C>, Among<K::Error, E, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let is_remove = key.is_remove();
 
@@ -1334,7 +1334,7 @@ where
     other: Either<&'a [u8], &K::Ref<'a>>,
   ) -> cmp::Ordering
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     match this {
       Among::Right(key) => match other {
diff --git a/src/generic/list/api.rs b/src/generic/list/api.rs
index 193f76c..4cf3c13 100644
--- a/src/generic/list/api.rs
+++ b/src/generic/list/api.rs
@@ -169,7 +169,7 @@ where
   pub fn contains_key<'a, Q>(&'a self, version: Version, key: &Q) -> bool
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.get(version, key).is_some()
   }
@@ -179,7 +179,7 @@ where
   pub fn contains_key_with_tombstone<'a, Q>(&'a self, version: Version, key: &Q) -> bool
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.get_with_tombstone(version, key).is_some()
   }
@@ -187,7 +187,7 @@ where
   /// Returns the first entry in the map.
   pub fn first<'a>(&'a self, version: Version) -> Option<EntryRef<'a, K, V, Active, A, RC, C>>
   where
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.iter(version).next()
   }
@@ -195,7 +195,7 @@ where
   /// Returns the last entry in the map.
   pub fn last<'a>(&'a self, version: Version) -> Option<EntryRef<'a, K, V, Active, A, RC, C>>
   where
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.iter(version).last()
   }
@@ -206,7 +206,7 @@ where
     version: Version,
   ) -> Option<EntryRef<'a, K, V, MaybeTombstone, A, RC, C>>
   where
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.iter_with_tombstone(version).next()
   }
@@ -217,7 +217,7 @@ where
     version: Version,
   ) -> Option<EntryRef<'a, K, V, MaybeTombstone, A, RC, C>>
   where
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.iter_with_tombstone(version).last()
   }
@@ -233,7 +233,7 @@ where
   ) -> Option<EntryRef<'a, K, V, Active, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     unsafe {
       let (n, eq) = self.find_near(version, key, false, true); // findLessOrEqual.
@@ -279,7 +279,7 @@ where
   ) -> Option<EntryRef<'a, K, V, MaybeTombstone, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     unsafe {
       let (n, eq) = self.find_near(version, key, false, true); // findLessOrEqual.
@@ -327,7 +327,7 @@ where
   ) -> Option<EntryRef<'a, K, V, Active, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.iter(version).map().seek_upper_bound(upper)
   }
@@ -341,7 +341,7 @@ where
   ) -> Option<EntryRef<'a, K, V, Active, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.iter(version).map().seek_lower_bound(lower)
   }
@@ -355,7 +355,7 @@ where
   ) -> Option<EntryRef<'a, K, V, MaybeTombstone, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self
       .iter_with_tombstone(version)
@@ -372,7 +372,7 @@ where
   ) -> Option<EntryRef<'a, K, V, MaybeTombstone, A, RC, C>>
   where
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self
       .iter_with_tombstone(version)
diff --git a/src/generic/list/api/update.rs b/src/generic/list/api/update.rs
index 0d5cbe3..8e2752d 100644
--- a/src/generic/list/api/update.rs
+++ b/src/generic/list/api/update.rs
@@ -35,7 +35,7 @@ where
     value: impl Into<MaybeStructured<'b, V>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<K::Error, V::Error, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.insert_at_height(version, self.random_height(), key, value)
   }
@@ -53,7 +53,7 @@ where
     value: impl Into<MaybeStructured<'b, V>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<K::Error, V::Error, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     let value: MaybeStructured<'_, V> = value.into();
@@ -107,7 +107,7 @@ where
     value_builder: ValueBuilder<impl FnOnce(&mut VacantBuffer<'a>) -> Result<usize, E>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<K::Error, E, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     self
@@ -150,7 +150,7 @@ where
     value: impl Into<MaybeStructured<'b, V>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<K::Error, V::Error, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     let value: MaybeStructured<'_, V> = value.into();
@@ -204,7 +204,7 @@ where
     value_builder: ValueBuilder<impl FnOnce(&mut VacantBuffer<'a>) -> Result<usize, E>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<K::Error, E, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     self
@@ -252,7 +252,7 @@ where
     value_builder: ValueBuilder<impl FnOnce(&mut VacantBuffer<'a>) -> Result<usize, VE>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<KE, VE, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .validate(height, key_builder.size(), value_builder.size())
@@ -308,7 +308,7 @@ where
     value_builder: ValueBuilder<impl FnOnce(&mut VacantBuffer<'a>) -> Result<usize, VE>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Among<KE, VE, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .validate(height, key_builder.size(), value_builder.size())
@@ -365,7 +365,7 @@ where
     failure: Ordering,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Either<K::Error, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     self
@@ -418,7 +418,7 @@ where
     key: impl Into<MaybeStructured<'b, K>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Either<K::Error, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     let key: MaybeStructured<'_, K> = key.into();
     self
@@ -470,7 +470,7 @@ where
     key_builder: KeyBuilder<impl FnOnce(&mut VacantBuffer<'a>) -> Result<usize, E>>,
   ) -> Result<Option<EntryRef<'a, K, V, Active, A, R, C>>, Either<E, Error>>
   where
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .validate(height, key_builder.size(), 0)
diff --git a/src/generic/list/entry.rs b/src/generic/list/entry.rs
index 76894cc..6a0224c 100644
--- a/src/generic/list/entry.rs
+++ b/src/generic/list/entry.rs
@@ -146,7 +146,7 @@ where
   S: State<'a>,
   A: Allocator,
   R: RefCounter,
-  C: TypeRefComparator<'a, Type = K>,
+  C: TypeRefComparator<'a, K>,
 {
   /// Returns the next entry in the map.
   #[inline]
diff --git a/src/generic/list/iterator.rs b/src/generic/list/iterator.rs
index d9d9e65..8a28acd 100644
--- a/src/generic/list/iterator.rs
+++ b/src/generic/list/iterator.rs
@@ -171,7 +171,7 @@ where
   RC: RefCounter,
   Q: ?Sized,
   R: RangeBounds<Q>,
-  C: TypeRefQueryComparator<'a, Q, Type = K>,
+  C: TypeRefQueryComparator<'a, K, Q>,
 {
   /// Advances to the next position. Returns the key and value if the
   /// iterator is pointing at a valid entry, and `None` otherwise.
@@ -398,7 +398,7 @@ where
   RC: RefCounter,
   Q: ?Sized,
   R: RangeBounds<Q>,
-  C: TypeRefQueryComparator<'a, Q, Type = K>,
+  C: TypeRefQueryComparator<'a, K, Q>,
 {
   /// Moves the iterator to the highest element whose key is below the given bound.
   /// If no such element is found then `None` is returned.
@@ -410,7 +410,7 @@ where
   ) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     self.head = None;
     self.tail = None;
@@ -436,7 +436,7 @@ where
   ) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     self.head = None;
     self.tail = None;
@@ -458,7 +458,7 @@ where
   fn seek_ge<QR>(&self, key: &QR) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     unsafe {
       let (n, _) = self.map.find_near(self.version, key, false, true);
@@ -496,7 +496,7 @@ where
   fn seek_gt<QR>(&self, key: &QR) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     unsafe {
       let (n, _) = self.map.find_near(Version::MIN, key, false, false);
@@ -534,7 +534,7 @@ where
   fn seek_le<QR>(&self, key: &QR) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     unsafe {
       let (n, _) = self.map.find_near(Version::MIN, key, true, true); // find less or equal.
@@ -572,7 +572,7 @@ where
   fn seek_lt<QR>(&self, key: &QR) -> Option<EntryRef<'a, K, V, S, A, RC, C>>
   where
     QR: ?Sized,
-    C: TypeRefQueryComparator<'a, QR, Type = K>,
+    C: TypeRefQueryComparator<'a, K, QR>,
   {
     unsafe {
       let (n, _) = self.map.find_near(self.version, key, true, false); // find less or equal.
@@ -631,7 +631,7 @@ where
   RC: RefCounter,
   Q: ?Sized,
   R: RangeBounds<Q>,
-  C: TypeRefQueryComparator<'a, Q, Type = K>,
+  C: TypeRefQueryComparator<'a, K, Q>,
 {
   type Item = EntryRef<'a, K, V, S, A, RC, C>;
 
@@ -680,7 +680,7 @@ where
   RC: RefCounter,
   Q: ?Sized,
   R: RangeBounds<Q>,
-  C: TypeRefQueryComparator<'a, Q, Type = K>,
+  C: TypeRefQueryComparator<'a, K, Q>,
 {
   #[inline]
   fn next_back(&mut self) -> Option<Self::Item> {
@@ -697,7 +697,7 @@ fn above_lower_bound_compare<'a, C, V, T>(cmp: &C, bound: &Bound<&T>, other: &V:
 where
   V: ?Sized + Type,
   T: ?Sized,
-  C: TypeRefQueryComparator<'a, T, Type = V>,
+  C: TypeRefQueryComparator<'a, V, T>,
 {
   match *bound {
     Bound::Unbounded => true,
@@ -709,7 +709,7 @@ where
 /// Helper function to check if a value is above a lower bound
 fn above_lower_bound<'a, C, K>(cmp: &C, bound: &Bound<&K::Ref<'a>>, other: &K::Ref<'a>) -> bool
 where
-  C: TypeRefComparator<'a, Type = K>,
+  C: TypeRefComparator<'a, K>,
   K: ?Sized + Type,
 {
   match *bound {
@@ -724,7 +724,7 @@ fn below_upper_bound_compare<'a, C, V, T>(cmp: &C, bound: &Bound<&T>, other: &V:
 where
   V: ?Sized + Type,
   T: ?Sized,
-  C: TypeRefQueryComparator<'a, T, Type = V>,
+  C: TypeRefQueryComparator<'a, V, T>,
 {
   match *bound {
     Bound::Unbounded => true,
@@ -736,7 +736,7 @@ where
 /// Helper function to check if a value is below an upper bound
 fn below_upper_bound<'a, C, K>(cmp: &C, bound: &Bound<&K::Ref<'a>>, other: &K::Ref<'a>) -> bool
 where
-  C: TypeRefComparator<'a, Type = K>,
+  C: TypeRefComparator<'a, K>,
   K: ?Sized + Type,
 {
   match *bound {
diff --git a/src/generic/multiple_version.rs b/src/generic/multiple_version.rs
index 9a3686e..31ea967 100644
--- a/src/generic/multiple_version.rs
+++ b/src/generic/multiple_version.rs
@@ -34,25 +34,25 @@ pub mod unsync {
     crate::__generic_multiple_version_map_tests!("unsync_multiple_version_map": super::SkipMap<[u8], [u8]>);
   }
 
-  type SkipList<K, V, C = Ascend<K>> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
+  type SkipList<K, V, C = Ascend> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
 
   /// Iterator over the [`SkipMap`].
-  pub type Iter<'a, K, V, S, C = Ascend<K>> =
+  pub type Iter<'a, K, V, S, C = Ascend> =
     super::super::iter::Iter<'a, K, V, S, Allocator, RefCounter, C>;
 
   /// Iterator over a subset of the [`SkipMap`].
-  pub type Range<'a, K, V, S, Q, R, C = Ascend<K>> =
+  pub type Range<'a, K, V, S, Q, R, C = Ascend> =
     super::super::iter::Iter<'a, K, V, S, Allocator, RefCounter, C, Q, R>;
 
   /// The entry reference of the [`SkipMap`].
-  pub type Entry<'a, K, V, S, C = Ascend<K>> =
+  pub type Entry<'a, K, V, S, C = Ascend> =
     super::super::entry::EntryRef<'a, K, V, S, Allocator, RefCounter, C>;
 
   /// A fast, ARENA based `SkipMap` that supports multiple versions, forward and backward iteration.
   ///
   /// If you want to use in concurrent environment, you can use [`multiple_version::sync::SkipMap`](crate::generic::multiple_version::sync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend<K>>(SkipList<K, V, C>);
+  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend>(SkipList<K, V, C>);
 
   impl<K: ?Sized, V: ?Sized, C: Clone> Clone for SkipMap<K, V, C> {
     #[inline]
@@ -138,25 +138,25 @@ pub mod sync {
     crate::__generic_multiple_version_map_tests!(go "sync_multiple_version_map": super::SkipMap<[u8], [u8]> => crate::tests::generic::TEST_OPTIONS_WITH_PESSIMISTIC_FREELIST);
   }
 
-  type SkipList<K, V, C = Ascend<K>> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
+  type SkipList<K, V, C = Ascend> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
 
   /// Iterator over the [`SkipMap`].
-  pub type Iter<'a, K, V, S, C = Ascend<K>> =
+  pub type Iter<'a, K, V, S, C = Ascend> =
     super::super::iter::Iter<'a, K, V, S, Allocator, RefCounter, C>;
 
   /// Iterator over a subset of the [`SkipMap`].
-  pub type Range<'a, K, V, S, Q, R, C = Ascend<K>> =
+  pub type Range<'a, K, V, S, Q, R, C = Ascend> =
     super::super::iter::Iter<'a, K, V, S, Allocator, RefCounter, C, Q, R>;
 
   /// The entry reference of the [`SkipMap`].
-  pub type Entry<'a, K, V, S, C = Ascend<K>> =
+  pub type Entry<'a, K, V, S, C = Ascend> =
     super::super::entry::EntryRef<'a, K, V, S, Allocator, RefCounter, C>;
 
   /// A fast, lock-free, thread-safe ARENA based `SkipMap` that supports multiple versions, forward and backward iteration.
   ///
   /// If you want to use in non-concurrent environment, you can use [`multiple_version::unsync::SkipMap`](crate::generic::multiple_version::unsync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend<K>>(SkipList<K, V, C>);
+  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend>(SkipList<K, V, C>);
 
   impl<K: ?Sized, V: ?Sized, C: Clone> Clone for SkipMap<K, V, C> {
     #[inline]
@@ -209,7 +209,7 @@ pub mod sync {
 ///
 /// - For concurrent environment, use [`sync::SkipMap`].
 /// - For non-concurrent environment, use [`unsync::SkipMap`].
-pub trait Map<K, V, C = Ascend<K>>
+pub trait Map<K, V, C = Ascend>
 where
   K: ?Sized + 'static,
   V: ?Sized + 'static,
@@ -351,7 +351,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return false;
@@ -382,7 +382,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return false;
@@ -400,7 +400,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -418,7 +418,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -439,7 +439,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -460,7 +460,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -500,7 +500,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -540,7 +540,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -561,7 +561,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -582,7 +582,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -606,7 +606,7 @@ where
 
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -629,7 +629,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     if !self.may_contain_version(version) {
       return None;
@@ -711,7 +711,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().insert(version, key, value)
   }
@@ -746,7 +746,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().insert_at_height(version, height, key, value)
   }
@@ -811,7 +811,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().insert_at_height_with_value_builder(
       version,
@@ -883,7 +883,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -909,7 +909,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -936,7 +936,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1003,7 +1003,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_insert_at_height_with_value_builder(
       version,
@@ -1076,7 +1076,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1148,7 +1148,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().insert_at_height_with_builders(
       version,
@@ -1226,7 +1226,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1296,7 +1296,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().get_or_insert_at_height_with_builders(
       version,
@@ -1371,7 +1371,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1400,7 +1400,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.compare_remove_at_height(version, self.random_height(), key, success, failure)
   }
@@ -1428,7 +1428,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1453,7 +1453,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_remove_at_height(version, self.random_height(), key)
   }
@@ -1490,7 +1490,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().get_or_remove_at_height(version, height, key)
   }
@@ -1551,7 +1551,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1616,7 +1616,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
diff --git a/src/generic/unique.rs b/src/generic/unique.rs
index 719ec53..a010c6a 100644
--- a/src/generic/unique.rs
+++ b/src/generic/unique.rs
@@ -34,25 +34,25 @@ pub mod unsync {
     crate::__generic_map_tests!("unsync_map": super::SkipMap<[u8], [u8]>);
   }
 
-  type SkipList<K, V, C = Ascend<K>> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
+  type SkipList<K, V, C = Ascend> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
 
   /// Iterator over the [`SkipMap`].
-  pub type Iter<'a, K, V, C = Ascend<K>> =
+  pub type Iter<'a, K, V, C = Ascend> =
     super::super::iter::Iter<'a, K, V, Active, Allocator, RefCounter, C>;
 
   /// Iterator over a subset of the [`SkipMap`].
-  pub type Range<'a, K, V, Q, R, C = Ascend<K>> =
+  pub type Range<'a, K, V, Q, R, C = Ascend> =
     super::super::iter::Iter<'a, K, V, Active, Allocator, RefCounter, C, Q, R>;
 
   /// The entry reference of the [`SkipMap`].
-  pub type Entry<'a, K, V, C = Ascend<K>> =
+  pub type Entry<'a, K, V, C = Ascend> =
     super::super::entry::EntryRef<'a, K, V, Active, Allocator, RefCounter, C>;
 
   /// A fast, ARENA based `SkipMap` that supports forward and backward iteration.
   ///
   /// If you want to use in concurrent environment, you can use [`unique::sync::SkipMap`](crate::generic::unique::sync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend<K>>(SkipList<K, V, C>);
+  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend>(SkipList<K, V, C>);
 
   impl<K: ?Sized, V: ?Sized> Clone for SkipMap<K, V> {
     #[inline]
@@ -133,25 +133,25 @@ pub mod sync {
     crate::__generic_map_tests!(go "sync_map": super::SkipMap<[u8], [u8]> => crate::tests::generic::TEST_OPTIONS_WITH_PESSIMISTIC_FREELIST);
   }
 
-  type SkipList<K, V, C = Ascend<K>> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
+  type SkipList<K, V, C = Ascend> = super::super::list::SkipList<K, V, Allocator, RefCounter, C>;
 
   /// Iterator over the [`SkipMap`].
-  pub type Iter<'a, K, V, C = Ascend<K>> =
+  pub type Iter<'a, K, V, C = Ascend> =
     super::super::iter::Iter<'a, K, V, Active, Allocator, RefCounter, C>;
 
   /// Iterator over a subset of the [`SkipMap`].
-  pub type Range<'a, K, V, Q, R, C = Ascend<K>> =
+  pub type Range<'a, K, V, Q, R, C = Ascend> =
     super::super::iter::Iter<'a, K, V, Active, Allocator, RefCounter, C, Q, R>;
 
   /// The entry reference of the [`SkipMap`].
-  pub type Entry<'a, K, V, C = Ascend<K>> =
+  pub type Entry<'a, K, V, C = Ascend> =
     super::super::entry::EntryRef<'a, K, V, Active, Allocator, RefCounter, C>;
 
   /// A fast, lock-free, thread-safe ARENA based `SkipMap` that supports forward and backward iteration.
   ///
   /// If you want to use in non-concurrent environment, you can use [`unique::unsync::SkipMap`](crate::generic::unique::unsync::SkipMap).
   #[repr(transparent)]
-  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend<K>>(SkipList<K, V, C>);
+  pub struct SkipMap<K: ?Sized, V: ?Sized, C = Ascend>(SkipList<K, V, C>);
 
   impl<K: ?Sized, V: ?Sized, C: Clone> Clone for SkipMap<K, V, C> {
     #[inline]
@@ -204,7 +204,7 @@ pub mod sync {
 ///
 /// - For concurrent environment, use [`sync::SkipMap`].
 /// - For non-concurrent environment, use [`unsync::SkipMap`].
-pub trait Map<K, V, C = Ascend<K>>
+pub trait Map<K, V, C = Ascend>
 where
   K: ?Sized + 'static,
   V: ?Sized + 'static,
@@ -316,7 +316,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.as_ref().contains_key(MIN_VERSION, key)
   }
@@ -327,7 +327,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.as_ref().first(MIN_VERSION)
   }
@@ -338,7 +338,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefQueryComparator<'a, K::Ref<'a>, Type = K>,
+    C: TypeRefQueryComparator<'a, K, K::Ref<'a>>,
   {
     self.as_ref().last(MIN_VERSION)
   }
@@ -370,7 +370,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.as_ref().get(MIN_VERSION, key)
   }
@@ -386,7 +386,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.as_ref().upper_bound(MIN_VERSION, upper)
   }
@@ -402,7 +402,7 @@ where
     K: Type,
     V: Type,
     Q: ?Sized,
-    C: TypeRefQueryComparator<'a, Q, Type = K>,
+    C: TypeRefQueryComparator<'a, K, Q>,
   {
     self.as_ref().lower_bound(MIN_VERSION, lower)
   }
@@ -449,7 +449,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.insert_at_height(self.random_height(), key, value)
   }
@@ -483,7 +483,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -550,7 +550,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.insert_at_height_with_value_builder(self.random_height(), key, value_builder)
   }
@@ -617,7 +617,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -642,7 +642,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_insert_at_height(self.random_height(), key, value)
   }
@@ -666,7 +666,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -733,7 +733,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_insert_at_height_with_value_builder(self.random_height(), key, value_builder)
   }
@@ -801,7 +801,7 @@ where
   where
     K: Type + 'b,
     V: Type + 'b,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().get_or_insert_at_height_with_value_builder(
       MIN_VERSION,
@@ -875,7 +875,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.insert_at_height_with_builders(self.random_height(), key_builder, value_builder)
   }
@@ -947,7 +947,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1016,7 +1016,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_insert_at_height_with_builders(self.random_height(), key_builder, value_builder)
   }
@@ -1085,7 +1085,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().get_or_insert_at_height_with_builders(
       MIN_VERSION,
@@ -1114,7 +1114,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.remove_at_height(self.random_height(), key)
   }
@@ -1140,7 +1140,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.as_ref().compare_remove_at_height(
       MIN_VERSION,
@@ -1168,7 +1168,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_remove_at_height(self.random_height(), key)
   }
@@ -1205,7 +1205,7 @@ where
   where
     K: Type + 'b,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
@@ -1267,7 +1267,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self.get_or_remove_at_height_with_builder(self.random_height(), key_builder)
   }
@@ -1329,7 +1329,7 @@ where
   where
     K: Type,
     V: Type,
-    C: TypeRefComparator<'a, Type = K>,
+    C: TypeRefComparator<'a, K>,
   {
     self
       .as_ref()
diff --git a/src/tests/generic.rs b/src/tests/generic.rs
index e9136a7..13e51e7 100644
--- a/src/tests/generic.rs
+++ b/src/tests/generic.rs
@@ -24,15 +24,15 @@ use crate::generic::{Ascend, Builder};
 
 use super::*;
 
-pub(crate) const TEST_OPTIONS: Builder<Ascend<[u8]>> =
+pub(crate) const TEST_OPTIONS: Builder<Ascend> =
   Builder::with(Ascend::new()).with_capacity(ARENA_SIZE as u32);
-pub(crate) const TEST_FULL_OPTIONS: Builder<Ascend<[u8]>> =
+pub(crate) const TEST_FULL_OPTIONS: Builder<Ascend> =
   Builder::with(Ascend::new()).with_capacity(1024);
-pub(crate) const TEST_OPTIONS_WITH_OPTIMISTIC_FREELIST: Builder<Ascend<[u8]>> =
+pub(crate) const TEST_OPTIONS_WITH_OPTIMISTIC_FREELIST: Builder<Ascend> =
   Builder::with(Ascend::new())
     .with_capacity(ARENA_SIZE as u32)
     .with_freelist(rarena_allocator::Freelist::Optimistic);
-pub(crate) const TEST_OPTIONS_WITH_PESSIMISTIC_FREELIST: Builder<Ascend<[u8]>> =
+pub(crate) const TEST_OPTIONS_WITH_PESSIMISTIC_FREELIST: Builder<Ascend> =
   Builder::with(Ascend::new())
     .with_capacity(ARENA_SIZE as u32)
     .with_freelist(rarena_allocator::Freelist::Pessimistic);
@@ -63,5 +63,5 @@ const BIG_ARENA_SIZE: usize = 120 << 20;
     test_generic_sync_versioned,
   )
 ))]
-pub(crate) const BIG_TEST_OPTIONS: Builder<Ascend<[u8]>> =
+pub(crate) const BIG_TEST_OPTIONS: Builder<Ascend> =
   Builder::with(Ascend::new()).with_capacity(BIG_ARENA_SIZE as u32);