chore: Fix clippy warnings (#2453)

Ans suppress some false positives, see rust-lang/rust-clippy#14091

neqo-common/src/codec.rs

@@ -162,7 +162,6 @@ impl<'a> Decoder<'a> {
 // Implement `AsRef` for `Decoder` so that values can be examined without
 // moving the cursor.
 impl<'a> AsRef<[u8]> for Decoder<'a> {
-    #[must_use]
     fn as_ref(&self) -> &'a [u8] {
         &self.buf[self.offset..]
     }
@@ -175,7 +174,6 @@ impl Debug for Decoder<'_> {
 }
 
 impl<'a> From<&'a [u8]> for Decoder<'a> {
-    #[must_use]
     fn from(buf: &'a [u8]) -> Self {
         Decoder::new(buf)
     }
@@ -185,14 +183,12 @@ impl<'a, T> From<&'a T> for Decoder<'a>
 where
     T: AsRef<[u8]>,
 {
-    #[must_use]
     fn from(buf: &'a T) -> Self {
         Decoder::new(buf.as_ref())
     }
 }
 
 impl<'b> PartialEq<Decoder<'b>> for Decoder<'_> {
-    #[must_use]
     fn eq(&self, other: &Decoder<'b>) -> bool {
         self.buf == other.buf
     }
@@ -452,14 +448,12 @@ impl AsMut<[u8]> for Encoder {
 }
 
 impl<'a> From<Decoder<'a>> for Encoder {
-    #[must_use]
     fn from(dec: Decoder<'a>) -> Self {
         Self::from(&dec.buf[dec.offset..])
     }
 }
 
 impl From<&[u8]> for Encoder {
-    #[must_use]
     fn from(buf: &[u8]) -> Self {
         Self {
             buf: Vec::from(buf),
@@ -468,7 +462,6 @@ impl From<&[u8]> for Encoder {
 }
 
 impl From<Encoder> for Vec<u8> {
-    #[must_use]
     fn from(buf: Encoder) -> Self {
         buf.buf
     }

neqo-common/src/datagram.rs

@@ -75,7 +75,6 @@ impl<D: AsRef<[u8]> + AsMut<[u8]>> DerefMut for Datagram<D> {
 
 impl<D: AsRef<[u8]>> Deref for Datagram<D> {
     type Target = [u8];
-    #[must_use]
     fn deref(&self) -> &Self::Target {
         AsRef::<[u8]>::as_ref(self)
     }

neqo-common/src/header.rs

@@ -36,11 +36,13 @@ impl Header {
         )
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     #[must_use]
     pub fn name(&self) -> &str {
         &self.name
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     #[must_use]
     pub fn value(&self) -> &str {
         &self.value

neqo-crypto/src/agent.rs

@@ -631,6 +631,7 @@ impl SecretAgent {
     }
 
     /// Return any fatal alert that the TLS stack might have sent.
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     #[must_use]
     pub fn alert(&self) -> Option<&Alert> {
         (*self.alert).as_ref()
@@ -773,7 +774,7 @@ impl SecretAgent {
             unsafe {
                 prio::PR_Close(self.fd.cast());
             }
-        };
+        }
         let _output = self.io.take_output();
         self.fd = null_mut();
     }
@@ -797,6 +798,7 @@ impl SecretAgent {
     }
 
     /// Get the active ECH configuration, which is empty if ECH is disabled.
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     #[must_use]
     pub fn ech_config(&self) -> &[u8] {
         &self.ech_config
@@ -915,6 +917,7 @@ impl Client {
         ssl::SECSuccess
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     #[must_use]
     pub fn server_name(&self) -> &str {
         &self.server_name
@@ -992,7 +995,6 @@ impl Client {
 
 impl Deref for Client {
     type Target = SecretAgent;
-    #[must_use]
     fn deref(&self) -> &SecretAgent {
         &self.agent
     }
@@ -1201,7 +1203,6 @@ impl Server {
 
 impl Deref for Server {
     type Target = SecretAgent;
-    #[must_use]
     fn deref(&self) -> &SecretAgent {
         &self.agent
     }
@@ -1228,7 +1229,6 @@ pub enum Agent {
 
 impl Deref for Agent {
     type Target = SecretAgent;
-    #[must_use]
     fn deref(&self) -> &SecretAgent {
         match self {
             Self::Client(c) => c,
@@ -1247,14 +1247,12 @@ impl DerefMut for Agent {
 }
 
 impl From<Client> for Agent {
-    #[must_use]
     fn from(c: Client) -> Self {
         Self::Client(c)
     }
 }
 
 impl From<Server> for Agent {
-    #[must_use]
     fn from(s: Server) -> Self {
         Self::Server(s)
     }

neqo-crypto/src/agentio.rs

@@ -123,7 +123,6 @@ impl RecordList {
 
 impl Deref for RecordList {
     type Target = Vec<Record>;
-    #[must_use]
     fn deref(&self) -> &Vec<Record> {
         &self.records
     }
@@ -141,7 +140,6 @@ impl Iterator for RecordListIter {
 impl IntoIterator for RecordList {
     type Item = Record;
     type IntoIter = RecordListIter;
-    #[must_use]
     fn into_iter(self) -> Self::IntoIter {
         RecordListIter(self.records.into_iter())
     }

neqo-crypto/src/auth.rs

@@ -37,7 +37,6 @@ pub enum AuthenticationStatus {
 }
 
 impl From<AuthenticationStatus> for PRErrorCode {
-    #[must_use]
     fn from(v: AuthenticationStatus) -> Self {
         v as Self
     }
@@ -46,7 +45,6 @@ impl From<AuthenticationStatus> for PRErrorCode {
 // Note that this mapping should be removed after gecko eventually learns how to
 // map into the enumerated type.
 impl From<PRErrorCode> for AuthenticationStatus {
-    #[must_use]
     fn from(v: PRErrorCode) -> Self {
         Self::from_repr(v).unwrap_or(Self::Unknown)
     }

neqo-crypto/src/err.rs

@@ -83,11 +83,9 @@ impl Error {
 }
 
 impl std::error::Error for Error {
-    #[must_use]
     fn cause(&self) -> Option<&dyn std::error::Error> {
         None
     }
-    #[must_use]
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         None
     }
@@ -100,13 +98,11 @@ impl std::fmt::Display for Error {
 }
 
 impl From<std::num::TryFromIntError> for Error {
-    #[must_use]
     fn from(_: std::num::TryFromIntError) -> Self {
         Self::IntegerOverflow
     }
 }
 impl From<std::ffi::NulError> for Error {
-    #[must_use]
     fn from(_: std::ffi::NulError) -> Self {
         Self::InternalError
     }

neqo-crypto/src/p11.rs

@@ -58,7 +58,6 @@ macro_rules! scoped_ptr {
 
         impl Deref for $scoped {
             type Target = *mut $target;
-            #[must_use]
             fn deref(&self) -> &*mut $target {
                 &self.ptr
             }
@@ -108,7 +107,6 @@ impl PublicKey {
 }
 
 impl Clone for PublicKey {
-    #[must_use]
     fn clone(&self) -> Self {
         let ptr = unsafe { SECKEY_CopyPublicKey(self.ptr) };
         assert!(!ptr.is_null());
@@ -163,7 +161,6 @@ impl PrivateKey {
 unsafe impl Send for PrivateKey {}
 
 impl Clone for PrivateKey {
-    #[must_use]
     fn clone(&self) -> Self {
         let ptr = unsafe { SECKEY_CopyPrivateKey(self.ptr) };
         assert!(!ptr.is_null());
@@ -211,7 +208,6 @@ impl SymKey {
 }
 
 impl Clone for SymKey {
-    #[must_use]
     fn clone(&self) -> Self {
         let ptr = unsafe { PK11_ReferenceSymKey(self.ptr) };
         assert!(!ptr.is_null());

neqo-crypto/src/secrets.rs

@@ -35,7 +35,6 @@ pub enum SecretDirection {
 }
 
 impl From<SSLSecretDirection::Type> for SecretDirection {
-    #[must_use]
     fn from(dir: SSLSecretDirection::Type) -> Self {
         Self::from_repr(dir).expect("Invalid secret direction")
     }

neqo-crypto/src/time.rs

@@ -141,7 +141,6 @@ impl TryInto<PRTime> for Time {
 }
 
 impl From<Time> for Instant {
-    #[must_use]
     fn from(t: Time) -> Self {
         t.t
     }

neqo-http3/src/connection.rs

@@ -125,13 +125,13 @@ The API consists of:
   - `webtransport_session_accept` -  only used by the server-side implementation
   - `webtransport_close_session`
   - `webtransport_create_stream_local` -  this function is called when an application wants to open
-     a new `WebTransport` stream. For example `Http3Client::webtransport_create_stream` will call
-     this function.
+    a new `WebTransport` stream. For example `Http3Client::webtransport_create_stream` will call
+    this function.
   - `webtransport_create_stream_remote` -  this is called when a `WebTransport` stream has been
-     opened by the peer and this function sets up the appropriate handler for the stream.
+    opened by the peer and this function sets up the appropriate handler for the stream.
 - functions that are called by `process_http3`
   - `process_sending` - some send-streams are buffered streams(see the Streams section) and this
-     function is called to trigger sending of the buffer data.
+    function is called to trigger sending of the buffer data.
 - functions that are called to  handle `ConnectionEvent`s:
   - `add_new_stream`
   - `handle_stream_readable`
@@ -171,15 +171,15 @@ There are the following types of streams:
 - `Decoder`: there is only a receiver stream of this type and the handler is `DecoderRecvStream`.
 - `Encoder`: there is only a receiver stream of this type and the handler is `EncoderRecvStream`.
 - `NewStream`: there is only a receiver stream of this type and the handler is
-               `NewStreamHeadReader`.
+  `NewStreamHeadReader`.
 - `Http`: `SendMessage` and `RecvMessage` handlers are responsible for this type of streams.
 - `Push`: `RecvMessage` is responsible for this type of streams.
 - `ExtendedConnect`: `WebTransportSession` is responsible sender and receiver handler.
 - `WebTransport(StreamId)`: `WebTransportSendStream` and `WebTransportRecvStream` are responsible
-                            sender and receiver handler.
+  sender and receiver handler.
 - `Unknown`: These are all other stream types that are not unknown to the current implementation
-             and should be handled properly by the spec, e.g., in our implementation the streams are
-             reset.
+  and should be handled properly by the spec, e.g., in our implementation the streams are
+  reset.
 
 The streams are registered in `send_streams` and `recv_streams` in following ways depending if they
 are local or remote:

neqo-http3/src/features/extended_connect/webtransport_session.rs

@@ -285,7 +285,7 @@ impl WebTransportSession {
                     SessionState::Done
                 };
             }
-        };
+        }
         Ok(())
     }
 

neqo-http3/src/server_events.rs

@@ -213,7 +213,6 @@ impl Http3OrWebTransportStream {
 
 impl Deref for Http3OrWebTransportStream {
     type Target = StreamHandler;
-    #[must_use]
     fn deref(&self) -> &Self::Target {
         &self.stream_handler
     }
@@ -382,7 +381,6 @@ impl WebTransportRequest {
 
 impl Deref for WebTransportRequest {
     type Target = StreamHandler;
-    #[must_use]
     fn deref(&self) -> &Self::Target {
         &self.stream_handler
     }

neqo-qpack/src/table.rs

@@ -49,10 +49,12 @@ impl DynamicTableEntry {
         self.refs -= 1;
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     pub fn name(&self) -> &[u8] {
         &self.name
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     pub fn value(&self) -> &[u8] {
         &self.value
     }

neqo-transport/src/cc/classic_cc.rs

@@ -149,30 +149,25 @@ impl<T: WindowAdjustment> CongestionControl for ClassicCongestionControl<T> {
         self.qlog = qlog;
     }
 
-    #[must_use]
     fn cwnd(&self) -> usize {
         self.congestion_window
     }
 
-    #[must_use]
     fn bytes_in_flight(&self) -> usize {
         self.bytes_in_flight
     }
 
-    #[must_use]
     fn cwnd_avail(&self) -> usize {
         // BIF can be higher than cwnd due to PTO packets, which are sent even
         // if avail is 0, but still count towards BIF.
         self.congestion_window.saturating_sub(self.bytes_in_flight)
     }
 
-    #[must_use]
     fn cwnd_min(&self) -> usize {
         self.max_datagram_size() * 2
     }
 
     #[cfg(test)]
-    #[must_use]
     fn cwnd_initial(&self) -> usize {
         cwnd_initial(self.pmtud.plpmtu())
     }

neqo-transport/src/cid.rs

@@ -314,6 +314,7 @@ impl ConnectionIdEntry<[u8; 16]> {
         true
     }
 
+    #[allow(clippy::missing_const_for_fn)] // TODO: False positive on nightly. Check periodically if this can be removed.
     pub fn is_empty(&self) -> bool {
         self.seqno == CONNECTION_ID_SEQNO_EMPTY || self.cid.is_empty()
     }