diff --git a/incrementalmerkletree/src/lib.rs b/incrementalmerkletree/src/lib.rs
index 08382d4..83df365 100644
--- a/incrementalmerkletree/src/lib.rs
+++ b/incrementalmerkletree/src/lib.rs
@@ -136,7 +136,7 @@ impl Level {
     // TODO: replace with an instance for `Step<Level>` once `step_trait`
     // is stabilized
     pub fn iter_to(self, other: Level) -> impl Iterator<Item = Self> {
-        (self.0..other.0).into_iter().map(Level)
+        (self.0..other.0).map(Level)
     }
 }
 
diff --git a/incrementalmerkletree/src/testing.rs b/incrementalmerkletree/src/testing.rs
index 51ed920..e34eccb 100644
--- a/incrementalmerkletree/src/testing.rs
+++ b/incrementalmerkletree/src/testing.rs
@@ -716,7 +716,6 @@ pub fn check_witnesses<T: Tree<String, usize> + std::fmt::Debug, F: Fn(usize) ->
     );
 
     let ops = ('a'..='l')
-        .into_iter()
         .map(|c| Append(c.to_string(), Marked))
         .chain(Some(Append('m'.to_string(), Ephemeral)))
         .chain(Some(Append('n'.to_string(), Ephemeral)))
diff --git a/incrementalmerkletree/src/testing/complete_tree.rs b/incrementalmerkletree/src/testing/complete_tree.rs
index 389883d..db4cb65 100644
--- a/incrementalmerkletree/src/testing/complete_tree.rs
+++ b/incrementalmerkletree/src/testing/complete_tree.rs
@@ -342,7 +342,7 @@ mod tests {
     #[test]
     fn correct_root() {
         const DEPTH: u8 = 3;
-        let values = (0..(1 << DEPTH)).into_iter().map(SipHashable);
+        let values = (0..(1 << DEPTH)).map(SipHashable);
 
         let mut tree = CompleteTree::<SipHashable, (), DEPTH>::new(100, ());
         for value in values {
@@ -391,7 +391,7 @@ mod tests {
         use crate::{testing::Tree, Retention};
 
         const DEPTH: u8 = 3;
-        let values = (0..(1 << DEPTH)).into_iter().map(SipHashable);
+        let values = (0..(1 << DEPTH)).map(SipHashable);
 
         let mut tree = CompleteTree::<SipHashable, (), DEPTH>::new(100, ());
         for value in values {
diff --git a/shardtree/src/lib.rs b/shardtree/src/lib.rs
index 817840d..aa0dcad 100644
--- a/shardtree/src/lib.rs
+++ b/shardtree/src/lib.rs
@@ -1819,7 +1819,7 @@ impl<
                         .and_modify(|to_clear| {
                             to_clear
                                 .entry(pos)
-                                .and_modify(|flags| *flags = *flags | RetentionFlags::CHECKPOINT)
+                                .and_modify(|flags| *flags |= RetentionFlags::CHECKPOINT)
                                 .or_insert(RetentionFlags::CHECKPOINT);
                         })
                         .or_insert_with(|| BTreeMap::from([(pos, RetentionFlags::CHECKPOINT)]));
@@ -1833,7 +1833,7 @@ impl<
                         .and_modify(|to_clear| {
                             to_clear
                                 .entry(*unmark_pos)
-                                .and_modify(|flags| *flags = *flags | RetentionFlags::MARKED)
+                                .and_modify(|flags| *flags |= RetentionFlags::MARKED)
                                 .or_insert(RetentionFlags::MARKED);
                         })
                         .or_insert_with(|| BTreeMap::from([(*unmark_pos, RetentionFlags::MARKED)]));