diff --git a/control_plane/src/compute.rs b/control_plane/src/compute.rs
index f95c2ba7b1..0b38af94b1 100644
--- a/control_plane/src/compute.rs
+++ b/control_plane/src/compute.rs
@@ -189,11 +189,11 @@ impl PostgresNode {
         );
         let port: u16 = CONF_PORT_RE
             .captures(config.as_str())
-            .ok_or(anyhow::Error::msg(err_msg.clone() + " 1"))?
+            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 1"))?
             .iter()
             .last()
-            .ok_or(anyhow::Error::msg(err_msg.clone() + " 2"))?
-            .ok_or(anyhow::Error::msg(err_msg.clone() + " 3"))?
+            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 2"))?
+            .ok_or_else(|| anyhow::Error::msg(err_msg.clone() + " 3"))?
             .as_str()
             .parse()
             .with_context(|| err_msg)?;
diff --git a/pageserver/src/basebackup.rs b/pageserver/src/basebackup.rs
index 6df812cde9..9141155d86 100644
--- a/pageserver/src/basebackup.rs
+++ b/pageserver/src/basebackup.rs
@@ -174,7 +174,7 @@ fn parse_rel_file_path(path: &str) -> Result<(), FilePathError> {
 
         Ok(())
     } else if let Some(dbpath) = path.strip_prefix("base/") {
-        let mut s = dbpath.split("/");
+        let mut s = dbpath.split('/');
         let dbnode_str = s
             .next()
             .ok_or_else(|| FilePathError::new("invalid relation data file name"))?;
diff --git a/pageserver/src/bin/pageserver.rs b/pageserver/src/bin/pageserver.rs
index 98c5eecee2..495ec41b65 100644
--- a/pageserver/src/bin/pageserver.rs
+++ b/pageserver/src/bin/pageserver.rs
@@ -169,9 +169,9 @@ fn start_pageserver(conf: &PageServerConf) -> Result<()> {
         .unwrap();
     threads.push(page_server_thread);
 
-    if tui_thread.is_some() {
+    if let Some(tui_thread) = tui_thread {
         // The TUI thread exits when the user asks to Quit.
-        tui_thread.unwrap().join().unwrap();
+        tui_thread.join().unwrap();
     } else {
         // In non-interactive mode, wait forever.
         for t in threads {
diff --git a/pageserver/src/page_cache.rs b/pageserver/src/page_cache.rs
index 85980b08ff..8b9692aaff 100644
--- a/pageserver/src/page_cache.rs
+++ b/pageserver/src/page_cache.rs
@@ -487,7 +487,7 @@ impl PageCache {
         let oldentry = shared.pagecache.insert(key, Arc::new(entry));
         self.num_entries.fetch_add(1, Ordering::Relaxed);
 
-        if !oldentry.is_none() {
+        if oldentry.is_some() {
             error!(
                 "overwriting WAL record with LSN {:X}/{:X} in page cache",
                 lsn >> 32,
diff --git a/pageserver/src/page_service.rs b/pageserver/src/page_service.rs
index 99e93c3925..db81333747 100644
--- a/pageserver/src/page_service.rs
+++ b/pageserver/src/page_service.rs
@@ -203,7 +203,7 @@ impl FeParseMessage {
         // now, just ignore the statement name, assuming that the client never
         // uses more than one prepared statement at a time.
         /*
-        if pstmt_name.len() != 0 {
+        if !pstmt_name.is_empty() {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidInput,
                 "named prepared statements not implemented in Parse",
@@ -235,7 +235,7 @@ impl FeDescribeMessage {
 
         // FIXME: see FeParseMessage::parse
         /*
-        if pstmt_name.len() != 0 {
+        if !pstmt_name.is_empty() {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidInput,
                 "named prepared statements not implemented in Describe",
@@ -266,7 +266,7 @@ impl FeExecuteMessage {
         let portal_name = read_null_terminated(&mut buf)?;
         let maxrows = buf.get_i32();
 
-        if portal_name.len() != 0 {
+        if !portal_name.is_empty() {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidInput,
                 "named portals not implemented",
@@ -293,7 +293,7 @@ impl FeBindMessage {
         let portal_name = read_null_terminated(&mut buf)?;
         let _pstmt_name = read_null_terminated(&mut buf)?;
 
-        if portal_name.len() != 0 {
+        if !portal_name.is_empty() {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidInput,
                 "named portals not implemented",
@@ -302,7 +302,7 @@ impl FeBindMessage {
 
         // FIXME: see FeParseMessage::parse
         /*
-        if pstmt_name.len() != 0 {
+        if !pstmt_name.is_empty() {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidInput,
                 "named prepared statements not implemented",
@@ -941,10 +941,10 @@ impl Connection {
         let f_tar2 = async {
             let joinres = f_tar.await;
 
-            if joinres.is_err() {
+            if let Err(joinreserr) = joinres {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidData,
-                    joinres.unwrap_err(),
+                    joinreserr,
                 ));
             }
             joinres.unwrap()
diff --git a/pageserver/src/restore_local_repo.rs b/pageserver/src/restore_local_repo.rs
index 8716536fb2..5cd927486a 100644
--- a/pageserver/src/restore_local_repo.rs
+++ b/pageserver/src/restore_local_repo.rs
@@ -186,10 +186,9 @@ fn restore_relfile(
     // Does it look like a relation file?
 
     let p = parse_relfilename(path.file_name().unwrap().to_str().unwrap());
-    if p.is_err() {
-        let e = p.unwrap_err();
+    if let Err(e) = p {
         warn!("unrecognized file in snapshot: {:?} ({})", path, e);
-        return Err(e)?;
+        return Err(e.into());
     }
     let (relnode, forknum, segno) = p.unwrap();
 
@@ -266,7 +265,7 @@ fn restore_wal(
 
         // It could be as .partial
         if !PathBuf::from(&path).exists() {
-            path = path + ".partial";
+            path += ".partial";
         }
 
         // Slurp the WAL file
diff --git a/pageserver/src/walredo.rs b/pageserver/src/walredo.rs
index 86e3ead64b..bf0159af4d 100644
--- a/pageserver/src/walredo.rs
+++ b/pageserver/src/walredo.rs
@@ -388,7 +388,7 @@ fn build_begin_redo_for_block_msg(tag: BufferTag) -> Bytes {
     let len = 4 + 5 * 4;
     let mut buf = BytesMut::with_capacity(1 + len);
 
-    buf.put_u8('B' as u8);
+    buf.put_u8(b'B');
     buf.put_u32(len as u32);
     buf.put_u32(tag.spcnode);
     buf.put_u32(tag.dbnode);
@@ -407,7 +407,7 @@ fn build_push_page_msg(tag: BufferTag, base_img: Bytes) -> Bytes {
     let len = 4 + 5 * 4 + base_img.len();
     let mut buf = BytesMut::with_capacity(1 + len);
 
-    buf.put_u8('P' as u8);
+    buf.put_u8(b'P');
     buf.put_u32(len as u32);
     buf.put_u32(tag.spcnode);
     buf.put_u32(tag.dbnode);
@@ -425,7 +425,7 @@ fn build_apply_record_msg(endlsn: u64, rec: Bytes) -> Bytes {
     let len = 4 + 8 + rec.len();
     let mut buf = BytesMut::with_capacity(1 + len);
 
-    buf.put_u8('A' as u8);
+    buf.put_u8(b'A');
     buf.put_u32(len as u32);
     buf.put_u64(endlsn);
     buf.put(rec);
@@ -439,7 +439,7 @@ fn build_get_page_msg(tag: BufferTag) -> Bytes {
     let len = 4 + 5 * 4;
     let mut buf = BytesMut::with_capacity(1 + len);
 
-    buf.put_u8('G' as u8);
+    buf.put_u8(b'G');
     buf.put_u32(len as u32);
     buf.put_u32(tag.spcnode);
     buf.put_u32(tag.dbnode);
diff --git a/walkeeper/src/pq_protocol.rs b/walkeeper/src/pq_protocol.rs
index f6e18d9aa4..57517c322f 100644
--- a/walkeeper/src/pq_protocol.rs
+++ b/walkeeper/src/pq_protocol.rs
@@ -91,9 +91,9 @@ impl FeStartupMessage {
                 options = true;
             } else if options {
                 for opt in p.split(' ') {
-                    if opt.starts_with("ztimelineid=") {
+                    if let Some(ztimelineid_str) = opt.strip_prefix("ztimelineid=") {
                         // FIXME: rethrow parsing error, don't unwrap
-                        timelineid = Some(ZTimelineId::from_str(&opt[12..]).unwrap());
+                        timelineid = Some(ZTimelineId::from_str(ztimelineid_str).unwrap());
                         break;
                     }
                 }
diff --git a/walkeeper/src/wal_service.rs b/walkeeper/src/wal_service.rs
index b02446cadf..9d7e6a8bfc 100644
--- a/walkeeper/src/wal_service.rs
+++ b/walkeeper/src/wal_service.rs
@@ -554,7 +554,7 @@ impl Connection {
     async fn run(&mut self) -> Result<()> {
         self.inbuf.resize(4, 0u8);
         self.stream.read_exact(&mut self.inbuf[0..4]).await?;
-        let startup_pkg_len = BigEndian::read_u32(&mut self.inbuf[0..4]);
+        let startup_pkg_len = BigEndian::read_u32(&self.inbuf[0..4]);
         if startup_pkg_len == 0 {
             self.receive_wal().await?; // internal protocol between wal_proposer and wal_acceptor
         } else {
@@ -997,12 +997,12 @@ impl Connection {
             // Try to fetch replica's feedback
             match self.stream.try_read_buf(&mut self.inbuf) {
                 Ok(0) => break,
-                Ok(_) => match self.parse_message()? {
-                    Some(FeMessage::CopyData(m)) => self
-                        .timeline()
-                        .add_hs_feedback(HotStandbyFeedback::parse(&m.body)),
-                    _ => {}
-                },
+                Ok(_) => {
+                    if let Some(FeMessage::CopyData(m)) = self.parse_message()? {
+                        self.timeline()
+                            .add_hs_feedback(HotStandbyFeedback::parse(&m.body))
+                    }
+                }
                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {}
                 Err(e) => {
                     return Err(e);
@@ -1102,7 +1102,7 @@ impl Connection {
         let mut bytes_written: usize = 0;
         let mut partial;
         let mut start_pos = startpos;
-        const ZERO_BLOCK: &'static [u8] = &[0u8; XLOG_BLCKSZ];
+        const ZERO_BLOCK: &[u8] = &[0u8; XLOG_BLCKSZ];
 
         /* Extract WAL location for this block */
         let mut xlogoff = XLogSegmentOffset(start_pos, wal_seg_size) as usize;
diff --git a/zenith/src/main.rs b/zenith/src/main.rs
index 05055f5c9e..8cbd97e1ea 100644
--- a/zenith/src/main.rs
+++ b/zenith/src/main.rs
@@ -186,7 +186,7 @@ fn handle_pg(pg_match: &ArgMatches, env: &local_env::LocalEnv) -> Result<()> {
             let node = cplane
                 .nodes
                 .get(name)
-                .ok_or(anyhow!("postgres {} is not found", name))?;
+                .ok_or_else(|| anyhow!("postgres {} is not found", name))?;
             node.start()?;
         }
         ("stop", Some(sub_m)) => {
@@ -194,7 +194,7 @@ fn handle_pg(pg_match: &ArgMatches, env: &local_env::LocalEnv) -> Result<()> {
             let node = cplane
                 .nodes
                 .get(name)
-                .ok_or(anyhow!("postgres {} is not found", name))?;
+                .ok_or_else(|| anyhow!("postgres {} is not found", name))?;
             node.stop()?;
         }
 
@@ -277,19 +277,19 @@ fn list_branches() -> Result<()> {
 //
 //
 fn parse_point_in_time(s: &str) -> Result<local_env::PointInTime> {
-    let mut strings = s.split("@");
+    let mut strings = s.split('@');
     let name = strings.next().unwrap();
 
     let lsn: Option<u64>;
     if let Some(lsnstr) = strings.next() {
-        let mut s = lsnstr.split("/");
+        let mut s = lsnstr.split('/');
         let lsn_hi: u64 = s
             .next()
-            .ok_or(anyhow!("invalid LSN in point-in-time specification"))?
+            .ok_or_else(|| anyhow!("invalid LSN in point-in-time specification"))?
             .parse()?;
         let lsn_lo: u64 = s
             .next()
-            .ok_or(anyhow!("invalid LSN in point-in-time specification"))?
+            .ok_or_else(|| anyhow!("invalid LSN in point-in-time specification"))?
             .parse()?;
         lsn = Some(lsn_hi << 32 | lsn_lo);
     } else {
@@ -312,11 +312,8 @@ fn parse_point_in_time(s: &str) -> Result<local_env::PointInTime> {
         let pointstr = fs::read_to_string(branchpath)?;
 
         let mut result = parse_point_in_time(&pointstr)?;
-        if lsn.is_some() {
-            result.lsn = lsn.unwrap();
-        } else {
-            result.lsn = 0;
-        }
+
+        result.lsn = lsn.unwrap_or(0);
         return Ok(result);
     }