diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9b05339..6c47181 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -78,12 +78,7 @@ jobs:
   clippy_check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: actions-rs/toolchain@v1
-        with:
-            toolchain: nightly
-            components: clippy
-            override: true
+      - uses: actions/checkout@v3
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/benches/transport_smtp.rs b/benches/transport_smtp.rs
index d92eccd..5d30118 100644
--- a/benches/transport_smtp.rs
+++ b/benches/transport_smtp.rs
@@ -24,7 +24,7 @@ fn bench_simple_send(c: &mut Criterion) {
                     vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
                 )
                 .unwrap(),
-                "id".to_string(),
+                "id",
                 "From: user@localhost\r\n\
                  Content-Type: text/plain\r\n\
                  \r\n\
@@ -55,7 +55,7 @@ fn bench_reuse_send(c: &mut Criterion) {
                     vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
                 )
                 .unwrap(),
-                "id".to_string(),
+                "id",
                 "From: user@localhost\r\n\
                  Content-Type: text/plain\r\n\
                  \r\n\
diff --git a/examples/smtp.rs b/examples/smtp.rs
index 3c56528..f2795b6 100644
--- a/examples/smtp.rs
+++ b/examples/smtp.rs
@@ -9,7 +9,7 @@ fn main() {
                 vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
             )
             .unwrap(),
-            "id".to_string(),
+            "id",
             "Hello ß☺ example".to_string().into_bytes(),
         );
 
diff --git a/examples/smtp_gmail.rs b/examples/smtp_gmail.rs
index b698dd9..f77d1e8 100644
--- a/examples/smtp_gmail.rs
+++ b/examples/smtp_gmail.rs
@@ -9,7 +9,7 @@ fn main() {
                 vec![EmailAddress::new("to@example.com".to_string()).unwrap()],
             )
             .unwrap(),
-            "id".to_string(),
+            "id",
             "Hello example".to_string().into_bytes(),
         );
 
diff --git a/src/smtp/client/codec.rs b/src/smtp/client/codec.rs
index 23f25b5..e9aa973 100644
--- a/src/smtp/client/codec.rs
+++ b/src/smtp/client/codec.rs
@@ -25,6 +25,7 @@ impl ClientCodec {
 impl ClientCodec {
     /// Adds transparency
     /// TODO: replace CR and LF by CRLF
+    #[allow(clippy::bool_to_int_with_if)]
     pub async fn encode<W: Write + Unpin>(&mut self, frame: &[u8], mut buf: W) -> io::Result<()> {
         match frame.len() {
             0 => {
diff --git a/src/smtp/commands.rs b/src/smtp/commands.rs
index f5eefaa..ab52b0c 100644
--- a/src/smtp/commands.rs
+++ b/src/smtp/commands.rs
@@ -312,7 +312,7 @@ impl AuthCommand {
             .ok_or(Error::ResponseParsing("Could not read auth challenge"))?;
         debug!("auth encoded challenge: {}", encoded_challenge);
 
-        let decoded_challenge = String::from_utf8(base64::decode(&encoded_challenge)?)?;
+        let decoded_challenge = String::from_utf8(base64::decode(encoded_challenge)?)?;
         debug!("auth decoded challenge: {}", decoded_challenge);
 
         let response = Some(mechanism.response(&credentials, Some(decoded_challenge.as_ref()))?);
@@ -383,7 +383,7 @@ mod test {
             "RCPT TO:<test@example.com>\r\n"
         );
         assert_eq!(
-            format!("{}", RcptCommand::new(email.clone(), vec![rcpt_parameter])),
+            format!("{}", RcptCommand::new(email, vec![rcpt_parameter])),
             "RCPT TO:<test@example.com> TEST=value\r\n"
         );
         assert_eq!(format!("{}", QuitCommand), "QUIT\r\n");
@@ -414,7 +414,7 @@ mod test {
         assert_eq!(
             format!(
                 "{}",
-                AuthCommand::new(Mechanism::Login, credentials.clone(), None).unwrap()
+                AuthCommand::new(Mechanism::Login, credentials, None).unwrap()
             ),
             "AUTH LOGIN\r\n"
         );
diff --git a/tests/transport_file.rs b/tests/transport_file.rs
index ce0efac..1e7d25f 100644
--- a/tests/transport_file.rs
+++ b/tests/transport_file.rs
@@ -18,7 +18,7 @@ mod test {
                     vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
                 )
                     .unwrap(),
-                "id".to_string(),
+                "id",
                 "Hello ß☺ example".to_string().into_bytes(),
             );
             let message_id = email.message_id().to_string();
diff --git a/tests/transport_sendmail.rs b/tests/transport_sendmail.rs
index 87321d0..88d4c69 100644
--- a/tests/transport_sendmail.rs
+++ b/tests/transport_sendmail.rs
@@ -14,7 +14,7 @@ mod test {
                     vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
                 )
                     .unwrap(),
-                "id".to_string(),
+                "id",
                 "Hello ß☺ example".to_string().into_bytes(),
             );
 
diff --git a/tests/transport_stub.rs b/tests/transport_stub.rs
index 6aa0c1c..db1cb09 100644
--- a/tests/transport_stub.rs
+++ b/tests/transport_stub.rs
@@ -13,7 +13,7 @@ mod test {
                 vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
             )
             .unwrap(),
-            "id".to_string(),
+            "id",
             "Hello ß☺ example".to_string().into_bytes(),
         );
         let email_ko = SendableEmail::new(
@@ -22,7 +22,7 @@ mod test {
                 vec![EmailAddress::new("root@localhost".to_string()).unwrap()],
             )
             .unwrap(),
-            "id".to_string(),
+            "id",
             "Hello ß☺ example".to_string().into_bytes(),
         );