diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2b8abfd..3b754b1 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,7 +15,7 @@ jobs:
           - windows
         toolchain:
           - stable
-          - 1.65
+          - 1.77
     name: cargo test on ${{ matrix.os }}, rust ${{ matrix.toolchain }}
     runs-on: ${{ matrix.os }}-latest
     steps:
diff --git a/src/impls/option.rs b/src/impls/option.rs
index b43ae73..608e003 100644
--- a/src/impls/option.rs
+++ b/src/impls/option.rs
@@ -125,6 +125,22 @@ where
     }
 }
 
+impl<T, TR> ReserveItems<Option<T>> for OptionRegion<TR>
+where
+    TR: Region + ReserveItems<T>,
+{
+    #[inline]
+    fn reserve_items<I>(&mut self, items: I)
+    where
+        I: Iterator<Item = Option<T>> + Clone,
+    {
+        // Clippy is confused about using `flatten` here, which we cannot use because
+        // the iterator isn't `Clone`.
+        #[allow(clippy::filter_map_identity)]
+        self.inner.reserve_items(items.filter_map(|r| r));
+    }
+}
+
 impl<'a, T: 'a, TR> ReserveItems<&'a Option<T>> for OptionRegion<TR>
 where
     TR: Region + ReserveItems<&'a T>,
@@ -148,6 +164,8 @@ mod tests {
     fn test_reserve() {
         let mut r = <OptionRegion<MirrorRegion<u8>>>::default();
         ReserveItems::reserve_items(&mut r, [Some(0), None].iter());
+
+        ReserveItems::reserve_items(&mut r, [Some(0), None].into_iter());
     }
 
     #[test]
diff --git a/src/impls/result.rs b/src/impls/result.rs
index b305d3e..05301c5 100644
--- a/src/impls/result.rs
+++ b/src/impls/result.rs
@@ -147,6 +147,21 @@ where
     }
 }
 
+impl<T, TC, E, EC> ReserveItems<Result<T, E>> for ResultRegion<TC, EC>
+where
+    TC: Region + ReserveItems<T>,
+    EC: Region + ReserveItems<E>,
+{
+    #[inline]
+    fn reserve_items<I>(&mut self, items: I)
+    where
+        I: Iterator<Item = Result<T, E>> + Clone,
+    {
+        self.oks.reserve_items(items.clone().filter_map(|r| r.ok()));
+        self.errs.reserve_items(items.filter_map(|r| r.err()));
+    }
+}
+
 impl<'a, T: 'a, TC, E: 'a, EC> ReserveItems<&'a Result<T, E>> for ResultRegion<TC, EC>
 where
     TC: Region + ReserveItems<&'a T>,
@@ -174,6 +189,8 @@ mod tests {
     fn test_reserve() {
         let mut r = <ResultRegion<MirrorRegion<u8>, MirrorRegion<u8>>>::default();
         ReserveItems::reserve_items(&mut r, [Ok(0), Err(1)].iter());
+
+        ReserveItems::reserve_items(&mut r, [Ok(0), Err(1)].into_iter());
     }
 
     #[test]
diff --git a/src/impls/slice.rs b/src/impls/slice.rs
index f129137..8d38b6d 100644
--- a/src/impls/slice.rs
+++ b/src/impls/slice.rs
@@ -1,5 +1,6 @@
 //! A region that stores slices.
 
+use std::cmp::Ordering;
 use std::fmt::{Debug, Formatter};
 use std::ops::{Deref, Range};
 
@@ -131,12 +132,6 @@ pub struct ReadSlice<'a, C: Region, O: OffsetContainer<C::Index> = Vec<<C as Reg
     Result<ReadSliceInner<'a, C, O>, &'a [C::Owned]>,
 );
 
-struct ReadSliceInner<'a, C: Region, O: OffsetContainer<C::Index> = Vec<<C as Region>::Index>> {
-    region: &'a SliceRegion<C, O>,
-    start: usize,
-    end: usize,
-}
-
 impl<C: Region, O: OffsetContainer<C::Index>> ReadSlice<'_, C, O> {
     /// Read the n-th item from the underlying region.
     ///
@@ -177,6 +172,45 @@ impl<C: Region, O: OffsetContainer<C::Index>> ReadSlice<'_, C, O> {
         self.into_iter()
     }
 }
+
+impl<R: Region, O: OffsetContainer<R::Index>> PartialEq for ReadSlice<'_, R, O>
+where
+    for<'a> R::ReadItem<'a>: PartialEq,
+{
+    fn eq(&self, other: &Self) -> bool {
+        self.iter().eq(*other)
+    }
+}
+
+impl<R: Region, O: OffsetContainer<R::Index>> Eq for ReadSlice<'_, R, O> where
+    for<'a> R::ReadItem<'a>: Eq
+{
+}
+
+impl<R: Region, O: OffsetContainer<R::Index>> PartialOrd for ReadSlice<'_, R, O>
+where
+    for<'a> R::ReadItem<'a>: PartialOrd,
+{
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        self.iter().partial_cmp(*other)
+    }
+}
+
+impl<R: Region, O: OffsetContainer<R::Index>> Ord for ReadSlice<'_, R, O>
+where
+    for<'a> R::ReadItem<'a>: Ord,
+{
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.iter().cmp(*other)
+    }
+}
+
+struct ReadSliceInner<'a, C: Region, O: OffsetContainer<C::Index> = Vec<<C as Region>::Index>> {
+    region: &'a SliceRegion<C, O>,
+    start: usize,
+    end: usize,
+}
+
 impl<C: Region, O: OffsetContainer<C::Index>> ReadSliceInner<'_, C, O> {
     /// Read the n-th item from the underlying region.
     ///
@@ -564,6 +598,57 @@ mod tests {
         assert_eq!("[1, 1, 1, 1]", format!("{:?}", r.index(index).clone()));
     }
 
+    #[test]
+    fn test_read_slice_eq() {
+        let mut r = <SliceRegion<MirrorRegion<u8>>>::default();
+        let index = r.push([1; 4]);
+
+        assert_eq!(
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 4]),
+            r.index(index)
+        );
+        assert_ne!(
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![0; 4]),
+            r.index(index)
+        );
+        assert_ne!(
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 5]),
+            r.index(index)
+        );
+    }
+
+    #[test]
+    fn test_read_slice_cmp() {
+        let mut r = <SliceRegion<MirrorRegion<u8>>>::default();
+        let index = r.push([1; 4]);
+
+        assert_eq!(
+            Ordering::Less,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![0; 4]).cmp(&r.index(index))
+        );
+        assert_eq!(
+            Ordering::Equal,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 4]).cmp(&r.index(index))
+        );
+        assert_eq!(
+            Ordering::Greater,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![2; 4]).cmp(&r.index(index))
+        );
+
+        assert_eq!(
+            Ordering::Less,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 3]).cmp(&r.index(index))
+        );
+        assert_eq!(
+            Ordering::Equal,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 4]).cmp(&r.index(index))
+        );
+        assert_eq!(
+            Ordering::Greater,
+            <ReadSlice<_, _> as IntoOwned>::borrow_as(&vec![1; 5]).cmp(&r.index(index))
+        );
+    }
+
     #[test]
     fn test_reserve_ref_slice() {
         let mut r = <SliceRegion<MirrorRegion<u8>>>::default();