Fix a few clippy warnings.

By either accepting clippy's suggestion, or by adding an 'allow'
directive to silence it.

pageserver/src/page_service.rs

@@ -663,7 +663,7 @@ impl Connection {
         debug!("process query {:?}", query_string);
 
         // remove null terminator, if any
-        let mut query_string = query_string.clone();
+        let mut query_string = query_string;
         if query_string.last() == Some(&0) {
             query_string.truncate(query_string.len() - 1);
         }

pageserver/src/tui.rs

@@ -171,6 +171,11 @@ pub fn ui_main() -> Result<(), Box<dyn Error>> {
         })?;
 
         // If ther user presses 'q', quit.
+
+        // silence clippy's suggestion to rewrite this as an if-statement. Match
+        // makes more sense as soon as we get another command than 'q'.
+        #[allow(clippy::single_match)]
+        #[allow(clippy::collapsible_match)]
         if let Event::Input(key) = events.next()? {
             match key {
                 Key::Char('q') => {

pageserver/src/walreceiver.rs

@@ -215,13 +215,13 @@ fn walreceiver_main(
 
                 waldecoder.feed_bytes(data);
 
-                loop {
-                    if let Some((lsn, recdata)) = waldecoder.poll_decode()? {
-                        let decoded = decode_wal_record(recdata.clone());
-                        timeline.save_decoded_record(decoded, recdata, lsn)?;
-                    } else {
-                        break;
-                    }
+                while let Some((lsn, recdata)) = waldecoder.poll_decode()? {
+                    let decoded = decode_wal_record(recdata.clone());
+                    timeline.save_decoded_record(decoded, recdata, lsn)?;
+
+                    // Now that this record has been handled, let the page cache know that
+                    // it is up-to-date to this LSN
+                    timeline.advance_last_record_lsn(lsn);
                 }
 
                 // Update the last_valid LSN value in the page cache one more time. We updated
@@ -317,7 +317,7 @@ pub fn identify_system(
             dbname: get_parse(first_row, 3).ok(),
         })
     } else {
-        Err(IdentifyError)?
+        Err(IdentifyError.into())
     }
 }
 

pageserver/src/walredo.rs

@@ -435,7 +435,7 @@ impl WalRedoProcess {
         &self,
         tag: BufferTag,
         base_img: Option<Bytes>,
-        records: &Vec<WALRecord>,
+        records: &[WALRecord],
     ) -> Result<Bytes, std::io::Error> {
         let mut stdin = self.stdin.borrow_mut();
         let mut stdout = self.stdout.borrow_mut();