diff --git a/zcash_history/examples/long.rs b/zcash_history/examples/long.rs
index bcd8d39f0..e074ff38a 100644
--- a/zcash_history/examples/long.rs
+++ b/zcash_history/examples/long.rs
@@ -80,7 +80,7 @@ fn prepare_tree(vec: &[NodeData]) -> Tree {
 }
 
 fn main() {
-    let number = match std::env::args().skip(1).next() {
+    let number = match std::env::args().nth(1) {
         None => {
             eprintln!("writer <number of nodes> [<out_file>]");
             std::process::exit(1);
diff --git a/zcash_history/src/tree.rs b/zcash_history/src/tree.rs
index 5c4881884..0e014cbfd 100644
--- a/zcash_history/src/tree.rs
+++ b/zcash_history/src/tree.rs
@@ -90,9 +90,8 @@ impl Tree {
 
         result.stored_count = length;
 
-        let mut gen = 0;
         let mut root = EntryLink::Stored(peaks[0].0);
-        for (idx, node) in peaks.into_iter() {
+        for (gen, (idx, node)) in peaks.into_iter().enumerate() {
             result.stored.insert(idx, node);
             if gen != 0 {
                 let next_generated = combine_nodes(
@@ -105,7 +104,6 @@ impl Tree {
                 );
                 root = result.push_generated(next_generated);
             }
-            gen += 1;
         }
 
         for (idx, node) in extra {
@@ -683,9 +681,10 @@ mod tests {
                     if number & (number - 1) == 0 {
                         if let EntryLink::Stored(_) = tree.root() { true }
                         else { false }
+                    } else if let EntryLink::Generated(_) = tree.root() {
+                        true
                     } else {
-                        if let EntryLink::Generated(_) = tree.root() { true }
-                        else { false }
+                        false
                     }
                 )
             }
@@ -711,9 +710,10 @@ mod tests {
                     if total & total - 1 == 0 {
                         if let EntryLink::Stored(_) = tree.root() { true }
                         else { false }
+                    } else if let EntryLink::Generated(_) = tree.root() {
+                        true
                     } else {
-                        if let EntryLink::Generated(_) = tree.root() { true }
-                        else { false }
+                        false
                     }
                 )
             }
diff --git a/zcash_primitives/src/merkle_tree.rs b/zcash_primitives/src/merkle_tree.rs
index 38bce1599..ef5a429e8 100644
--- a/zcash_primitives/src/merkle_tree.rs
+++ b/zcash_primitives/src/merkle_tree.rs
@@ -607,11 +607,11 @@ mod tests {
     #[test]
     fn empty_root_test_vectors() {
         let mut tmp = [0u8; 32];
-        for i in 0..HEX_EMPTY_ROOTS.len() {
+        for (i, &expected) in HEX_EMPTY_ROOTS.iter().enumerate() {
             Node::empty_root(i)
                 .write(&mut tmp[..])
                 .expect("length is 32 bytes");
-            assert_eq!(hex::encode(tmp), HEX_EMPTY_ROOTS[i]);
+            assert_eq!(hex::encode(tmp), expected);
         }
     }
 
@@ -632,11 +632,11 @@ mod tests {
     fn empty_commitment_tree_roots() {
         let tree = CommitmentTree::<Node>::new();
         let mut tmp = [0u8; 32];
-        for i in 1..HEX_EMPTY_ROOTS.len() {
+        for (i, &expected) in HEX_EMPTY_ROOTS.iter().enumerate().skip(1) {
             tree.root_inner(i, PathFiller::empty())
                 .write(&mut tmp[..])
                 .expect("length is 32 bytes");
-            assert_eq!(hex::encode(tmp), HEX_EMPTY_ROOTS[i]);
+            assert_eq!(hex::encode(tmp), expected);
         }
     }
 
diff --git a/zcash_primitives/src/primitives.rs b/zcash_primitives/src/primitives.rs
index 09996d42a..1cdf27c5b 100644
--- a/zcash_primitives/src/primitives.rs
+++ b/zcash_primitives/src/primitives.rs
@@ -143,9 +143,7 @@ impl PaymentAddress {
             Diversifier(tmp)
         };
         // Check that the diversifier is valid
-        if diversifier.g_d().is_none() {
-            return None;
-        }
+        diversifier.g_d()?;
 
         let pk_d = jubjub::SubgroupPoint::from_bytes(bytes[11..43].try_into().unwrap());
         if pk_d.is_some().into() {
diff --git a/zcash_primitives/src/redjubjub.rs b/zcash_primitives/src/redjubjub.rs
index 585080278..0382dc28f 100644
--- a/zcash_primitives/src/redjubjub.rs
+++ b/zcash_primitives/src/redjubjub.rs
@@ -191,9 +191,7 @@ pub fn batch_verify<'a, R: RngCore>(
         acc = acc + r + (&entry.vk.0 * c) + (p_g * s);
     }
 
-    acc = acc.mul_by_cofactor().into();
-
-    acc.is_identity().into()
+    acc.mul_by_cofactor().is_identity().into()
 }
 
 #[cfg(test)]
diff --git a/zcash_primitives/src/transaction/tests.rs b/zcash_primitives/src/transaction/tests.rs
index 5aa8254d2..8b7762b97 100644
--- a/zcash_primitives/src/transaction/tests.rs
+++ b/zcash_primitives/src/transaction/tests.rs
@@ -226,12 +226,9 @@ fn test_tze_tx_parse() {
     match tx {
         Ok(tx) => assert!(!tx.tze_inputs.is_empty()),
 
-        Err(e) => assert!(
-            false,
-            format!(
-                "An error occurred parsing a serialized TZE transaction: {}",
-                e
-            )
+        Err(e) => panic!(
+            "An error occurred parsing a serialized TZE transaction: {}",
+            e
         ),
     }
 }