diff --git a/boltconn/src/app.rs b/boltconn/src/app.rs
index d95ae77..d523585 100644
--- a/boltconn/src/app.rs
+++ b/boltconn/src/app.rs
@@ -495,13 +495,13 @@ async fn start_tun_services(
     #[cfg(unix)]
     let tcp_listener = tokio::net::TcpListener::bind(tun_inbound_tcp.nat_addr())
         .await
-        .or_else(|e| {
+        .map_err(|e| {
             tracing::error!(
                 "Failed to start NAT at {}: {}",
                 tun_inbound_tcp.nat_addr(),
                 e
             );
-            Err(e)
+            e
         })?;
     #[cfg(windows)]
     let tcp_listener = {
diff --git a/boltconn/src/external/uds_controller.rs b/boltconn/src/external/uds_controller.rs
index 6ecf518..d06991d 100644
--- a/boltconn/src/external/uds_controller.rs
+++ b/boltconn/src/external/uds_controller.rs
@@ -43,10 +43,10 @@ impl UnixListenerGuard {
                     .chown(&path)
                     .map_err(|e| SystemError::Controller(as_io_err(e)))?;
             }
-            return Ok(Self {
+            Ok(Self {
                 path: path.to_string_lossy().to_string(),
                 listener: Some(listener),
-            });
+            })
         }
         #[cfg(windows)]
         {
@@ -54,10 +54,10 @@ impl UnixListenerGuard {
                 .first_pipe_instance(true)
                 .create(path)
                 .map_err(SystemError::Controller)?;
-            return Ok(Self {
+            Ok(Self {
                 path: path.to_string(),
                 listener: tokio::sync::Mutex::new(listener),
-            });
+            })
         }
     }
 
diff --git a/boltconn/src/platform/process/windows.rs b/boltconn/src/platform/process/windows.rs
index eff9b91..bf16bef 100644
--- a/boltconn/src/platform/process/windows.rs
+++ b/boltconn/src/platform/process/windows.rs
@@ -224,7 +224,7 @@ impl RecordSearcher {
         for i in 0..(record_cnt as usize) {
             let record = data
                 .get((4 + i * self.item_size)..(4 + (i + 1) * self.item_size))
-                .ok_or_else(|| std::io::ErrorKind::NotFound)?;
+                .ok_or(std::io::ErrorKind::NotFound)?;
             // only check established TCP record
             if let Some(tcp_state_offset) = self.tcp_state {
                 let tcp_state = slice_to_u32(&record[tcp_state_offset..tcp_state_offset + 4]);
diff --git a/boltconn/src/platform/sys/windows_sys.rs b/boltconn/src/platform/sys/windows_sys.rs
index 0671dbd..e4ce274 100644
--- a/boltconn/src/platform/sys/windows_sys.rs
+++ b/boltconn/src/platform/sys/windows_sys.rs
@@ -186,7 +186,7 @@ impl SystemDnsHandle {
 impl Drop for SystemDnsHandle {
     fn drop(&mut self) {
         for record in self.old_dns.iter() {
-            if let Some(dns) = record.dns_server.get(0) {
+            if let Some(dns) = record.dns_server.first() {
                 let _ = run_command(Command::new("netsh").args([
                     "interface",
                     "ipv4",
@@ -194,7 +194,7 @@ impl Drop for SystemDnsHandle {
                     "dnsservers",
                     &format!("name={}", record.iface_name),
                     "source=static",
-                    &format!("address={}", dns.to_string()),
+                    &format!("address={}", dns),
                     "register=none",
                     "validate=no",
                 ]));