fix: more clippy warnings in mssql modules

- Fix unit_arg by using () instead of Default::default()
- Fix redundant_closure by using function reference directly
- Fix while_let_on_iterator by using for loop
- Fix explicit_auto_deref in mssql/options/parse.rs
- Add allow for result_large_err in requested_packet_size
- Fix needless_range_loop by iterating over slice directly
- Add allow for ptr_arg where Vec-specific methods are used

Author: cursoragent

sqlx-core/src/mssql/connection/tls_prelogin_stream_wrapper.rs

@@ -100,14 +100,14 @@ impl<S: AsyncRead + AsyncWrite + Unpin + Send> AsyncRead for TlsPreloginWrapper<
 
                 let read = header_buf.filled().len();
                 if read == 0 {
-                    return Poll::Ready(Ok(Default::default()));
+                    return Poll::Ready(Ok(()));
                 }
 
                 inner.header_pos += read;
             }
 
             let header: PacketHeader = Decode::decode(Bytes::copy_from_slice(&inner.header_buf))
-                .map_err(|err| io::Error::other(err))?;
+                .map_err(io::Error::other)?;
 
             inner.read_remaining = usize::from(header.length) - HEADER_BYTES;
 
@@ -153,14 +153,14 @@ impl<S: AsyncRead + AsyncWrite + Unpin + Send> AsyncRead for TlsPreloginWrapper<
                 let read = ready!(Pin::new(&mut inner.stream).poll_read(cx, header_buf))?;
 
                 if read == 0 {
-                    return Poll::Ready(Ok(Default::default()));
+                    return Poll::Ready(Ok(()));
                 }
 
                 inner.header_pos += read;
             }
 
             let header: PacketHeader = Decode::decode(Bytes::copy_from_slice(&inner.header_buf))
-                .map_err(|err| io::Error::other(err))?;
+                .map_err(io::Error::other)?;
 
             inner.read_remaining = usize::from(header.length) - HEADER_BYTES;
 

sqlx-core/src/mssql/io/buf_mut.rs

@@ -6,7 +6,7 @@ pub trait MssqlBufMutExt {
 impl MssqlBufMutExt for Vec<u8> {
     fn put_utf16_str(&mut self, s: &str) {
         let mut enc = s.encode_utf16();
-        while let Some(ch) = enc.next() {
+        for ch in enc {
             self.extend_from_slice(&ch.to_le_bytes());
         }
     }

sqlx-core/src/mssql/options/mod.rs

@@ -134,6 +134,7 @@ impl MssqlConnectOptions {
 
     /// Size in bytes of TDS packets to exchange with the server.
     /// Returns an error if the size is smaller than 512 bytes
+    #[allow(clippy::result_large_err)]
     pub fn requested_packet_size(mut self, size: u32) -> Result<Self, Self> {
         if size < 512 {
             Err(self)

sqlx-core/src/mssql/options/parse.rs

@@ -60,15 +60,15 @@ impl FromStr for MssqlConnectOptions {
         let username = url.username();
         if !username.is_empty() {
             options = options.username(
-                &*percent_decode_str(username)
+                &percent_decode_str(username)
                     .decode_utf8()
                     .map_err(Error::config)?,
             );
         }
 
         if let Some(password) = url.password() {
             options = options.password(
-                &*percent_decode_str(password)
+                &percent_decode_str(password)
                     .decode_utf8()
                     .map_err(Error::config)?,
             );
@@ -82,7 +82,7 @@ impl FromStr for MssqlConnectOptions {
         for (key, value) in url.query_pairs() {
             match key.as_ref() {
                 "instance" => {
-                    options = options.instance(&*value);
+                    options = options.instance(&value);
                 }
                 "encrypt" => {
                     match value.to_lowercase().as_str() {
@@ -104,7 +104,7 @@ impl FromStr for MssqlConnectOptions {
                     options = options.trust_server_certificate(trust);
                 }
                 "hostname_in_certificate" => {
-                    options = options.hostname_in_certificate(&*value);
+                    options = options.hostname_in_certificate(&value);
                 }
                 "packet_size" => {
                     let size = value.parse().map_err(Error::config)?;
@@ -116,11 +116,11 @@ impl FromStr for MssqlConnectOptions {
                     options = options.client_program_version(value.parse().map_err(Error::config)?)
                 }
                 "client_pid" => options = options.client_pid(value.parse().map_err(Error::config)?),
-                "hostname" => options = options.hostname(&*value),
-                "app_name" => options = options.app_name(&*value),
-                "server_name" => options = options.server_name(&*value),
-                "client_interface_name" => options = options.client_interface_name(&*value),
-                "language" => options = options.language(&*value),
+                "hostname" => options = options.hostname(&value),
+                "app_name" => options = options.app_name(&value),
+                "server_name" => options = options.server_name(&value),
+                "client_interface_name" => options = options.client_interface_name(&value),
+                "language" => options = options.language(&value),
                 _ => {
                     return Err(Error::config(MssqlInvalidOption(key.into())));
                 }

sqlx-core/src/mssql/protocol/login.rs

@@ -97,9 +97,8 @@ impl Encode<'_> for Login7<'_> {
         // password buffer starting with the position pointed to by ibPassword or
         // ibChangePassword, the client SHOULD first swap the four high bits with
         // the four low bits and then do a bit-XOR with 0xA5 (10100101).
-        for i in password_start..buf.len() {
-            let b = buf[i];
-            buf[i] = ((b << 4) & 0xf0 | (b >> 4) & 0x0f) ^ 0xa5;
+        for b in &mut buf[password_start..] {
+            *b = ((*b << 4) & 0xf0 | (*b >> 4) & 0x0f) ^ 0xa5;
         }
 
         // [AppName] The client application name
@@ -143,6 +142,7 @@ impl Encode<'_> for Login7<'_> {
     }
 }
 
+#[allow(clippy::ptr_arg)]
 fn write_offset(buf: &mut Vec<u8>, offsets: &mut usize, beg: usize) {
     // The offset must be relative to the beginning of the packet payload, after
     // the packet header

sqlx-core/src/mssql/protocol/pre_login.rs

@@ -195,6 +195,7 @@ enum PreLoginOptionToken {
 }
 
 impl PreLoginOptionToken {
+    #[allow(clippy::ptr_arg)]
     fn put(self, buf: &mut Vec<u8>, pos: &mut usize, offset: &mut u16, len: u16) {
         buf[*pos] = self as u8;
         *pos += 1;