Activate more lints

Cargo.toml

@@ -46,6 +46,7 @@ uninlined_format_args = "warn"
 unnested_or_patterns = "warn"
 unused_self = "warn"
 verbose_file_reads = "warn"
+must_use_candidate = "warn"
 
 # configuration for https://github.com/crate-ci/typos
 [workspace.metadata.typos.default.extend-identifiers]

axum-core/src/body.rs

@@ -48,6 +48,7 @@ impl Body {
     }
 
     /// Create an empty body.
+    #[must_use]
     pub fn empty() -> Self {
         Self::new(http_body_util::Empty::new())
     }
@@ -72,6 +73,7 @@ impl Body {
     /// you need a [`Stream`] of all frame types.
     ///
     /// [`http_body_util::BodyStream`]: https://docs.rs/http-body-util/latest/http_body_util/struct.BodyStream.html
+    #[must_use]
     pub fn into_data_stream(self) -> BodyDataStream {
         BodyDataStream { inner: self }
     }

axum-core/src/error.rs

@@ -16,6 +16,7 @@ impl Error {
     }
 
     /// Convert an `Error` back into the underlying boxed trait object.
+    #[must_use]
     pub fn into_inner(self) -> BoxError {
         self.inner
     }

axum-core/src/macros.rs

@@ -106,11 +106,13 @@ macro_rules! __define_rejection {
             }
 
             /// Get the response body text used for this rejection.
+            #[must_use]
             pub fn body_text(&self) -> String {
                 self.to_string()
             }
 
             /// Get the status code used for this rejection.
+            #[must_use]
             pub fn status(&self) -> http::StatusCode {
                 http::StatusCode::$status
             }
@@ -179,6 +181,7 @@ macro_rules! __composite_rejection {
 
         impl $name {
             /// Get the response body text used for this rejection.
+            #[must_use]
             pub fn body_text(&self) -> String {
                 match self {
                     $(
@@ -188,6 +191,7 @@ macro_rules! __composite_rejection {
             }
 
             /// Get the status code used for this rejection.
+            #[must_use]
             pub fn status(&self) -> http::StatusCode {
                 match self {
                     $(

axum-extra/src/extract/cookie/mod.rs

@@ -118,6 +118,7 @@ impl CookieJar {
     /// run extractors. Normally you should create `CookieJar`s through [`FromRequestParts`].
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn from_headers(headers: &HeaderMap) -> Self {
         let mut jar = cookie::CookieJar::new();
         for cookie in cookies_from_request(headers) {
@@ -135,6 +136,7 @@ impl CookieJar {
     /// CookieJar`.
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn new() -> Self {
         Self::default()
     }
@@ -153,6 +155,7 @@ impl CookieJar {
     ///         .map(|cookie| cookie.value().to_owned());
     /// }
     /// ```
+    #[must_use]
     pub fn get(&self, name: &str) -> Option<&Cookie<'static>> {
         self.jar.get(name)
     }

axum-extra/src/extract/cookie/private.rs

@@ -153,6 +153,7 @@ impl PrivateCookieJar {
     /// run extractors. Normally you should create `PrivateCookieJar`s through [`FromRequestParts`].
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn from_headers(headers: &HeaderMap, key: Key) -> Self {
         let mut jar = cookie::CookieJar::new();
         let mut private_jar = jar.private_mut(&key);
@@ -175,6 +176,7 @@ impl PrivateCookieJar {
     /// run extractors. Normally you should create `PrivateCookieJar`s through [`FromRequestParts`].
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn new(key: Key) -> Self {
         Self {
             jar: Default::default(),
@@ -201,6 +203,7 @@ impl<K> PrivateCookieJar<K> {
     ///         .map(|cookie| cookie.value().to_owned());
     /// }
     /// ```
+    #[must_use]
     pub fn get(&self, name: &str) -> Option<Cookie<'static>> {
         self.private_jar().get(name)
     }
@@ -246,6 +249,7 @@ impl<K> PrivateCookieJar<K> {
 
     /// Authenticates and decrypts `cookie`, returning the plaintext version if decryption succeeds
     /// or `None` otherwise.
+    #[must_use]
     pub fn decrypt(&self, cookie: Cookie<'static>) -> Option<Cookie<'static>> {
         self.private_jar().decrypt(cookie)
     }

axum-extra/src/extract/cookie/signed.rs

@@ -170,6 +170,7 @@ impl SignedCookieJar {
     /// run extractors. Normally you should create `SignedCookieJar`s through [`FromRequestParts`].
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn from_headers(headers: &HeaderMap, key: Key) -> Self {
         let mut jar = cookie::CookieJar::new();
         let mut signed_jar = jar.signed_mut(&key);
@@ -192,6 +193,7 @@ impl SignedCookieJar {
     /// run extractors. Normally you should create `SignedCookieJar`s through [`FromRequestParts`].
     ///
     /// [`FromRequestParts`]: axum::extract::FromRequestParts
+    #[must_use]
     pub fn new(key: Key) -> Self {
         Self {
             jar: Default::default(),
@@ -219,6 +221,7 @@ impl<K> SignedCookieJar<K> {
     ///         .map(|cookie| cookie.value().to_owned());
     /// }
     /// ```
+    #[must_use]
     pub fn get(&self, name: &str) -> Option<Cookie<'static>> {
         self.signed_jar().get(name)
     }
@@ -264,6 +267,7 @@ impl<K> SignedCookieJar<K> {
 
     /// Verifies the authenticity and integrity of `cookie`, returning the plaintext version if
     /// verification succeeds or `None` otherwise.
+    #[must_use]
     pub fn verify(&self, cookie: Cookie<'static>) -> Option<Cookie<'static>> {
         self.signed_jar().verify(cookie)
     }

axum-extra/src/extract/multipart.rs

@@ -150,23 +150,27 @@ impl Field {
     /// The field name found in the
     /// [`Content-Disposition`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition)
     /// header.
+    #[must_use]
     pub fn name(&self) -> Option<&str> {
         self.inner.name()
     }
 
     /// The file name found in the
     /// [`Content-Disposition`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition)
     /// header.
+    #[must_use]
     pub fn file_name(&self) -> Option<&str> {
         self.inner.file_name()
     }
 
     /// Get the [content type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type) of the field.
+    #[must_use]
     pub fn content_type(&self) -> Option<&str> {
         self.inner.content_type().map(|m| m.as_ref())
     }
 
     /// Get a map of headers as [`HeaderMap`].
+    #[must_use]
     pub fn headers(&self) -> &HeaderMap {
         self.inner.headers()
     }
@@ -253,6 +257,7 @@ impl MultipartError {
     }
 
     /// Get the status code used for this rejection.
+    #[must_use]
     pub fn status(&self) -> http::StatusCode {
         status_code_from_multer_error(&self.source)
     }

axum-extra/src/response/multiple.rs

@@ -24,6 +24,7 @@ impl MultipartForm {
     /// let parts: Vec<Part> = vec![Part::text("foo".to_string(), "abc"), Part::text("bar".to_string(), "def")];
     /// let form = MultipartForm::with_parts(parts);
     /// ```
+    #[must_use]
     pub fn with_parts(parts: Vec<Part>) -> Self {
         MultipartForm { parts }
     }
@@ -103,6 +104,7 @@ impl Part {
     /// let parts: Vec<Part> = vec![Part::text("foo".to_string(), "abc")];
     /// let form = MultipartForm::from_iter(parts);
     /// ```
+    #[must_use]
     pub fn text(name: String, contents: &str) -> Self {
         Self {
             name,
@@ -127,6 +129,7 @@ impl Part {
     /// let parts: Vec<Part> = vec![Part::file("foo", "foo.txt", vec![0x68, 0x68, 0x20, 0x6d, 0x6f, 0x6d])];
     /// let form = MultipartForm::from_iter(parts);
     /// ```
+    #[must_use]
     pub fn file(field_name: &str, file_name: &str, contents: Vec<u8>) -> Self {
         Self {
             name: field_name.to_owned(),

axum-extra/src/routing/mod.rs

@@ -28,6 +28,7 @@ pub use self::typed::{SecondElementIs, TypedPath};
 // Validates a path at compile time, used with the vpath macro.
 #[rustversion::since(1.80)]
 #[doc(hidden)]
+#[must_use]
 pub const fn __private_validate_static_path(path: &'static str) -> &'static str {
     if path.is_empty() {
         panic!("Paths must start with a `/`. Use \"/\" for root routes")

axum-extra/src/typed_header.rs

@@ -137,11 +137,13 @@ pub struct TypedHeaderRejection {
 
 impl TypedHeaderRejection {
     /// Name of the header that caused the rejection
+    #[must_use]
     pub fn name(&self) -> &http::header::HeaderName {
         self.name
     }
 
     /// Reason why the header extraction has failed
+    #[must_use]
     pub fn reason(&self) -> &TypedHeaderRejectionReason {
         &self.reason
     }

axum/src/extract/matched_path.rs

@@ -58,6 +58,7 @@ pub struct MatchedPath(pub(crate) Arc<str>);
 
 impl MatchedPath {
     /// Returns a `str` representation of the path.
+    #[must_use]
     pub fn as_str(&self) -> &str {
         &self.0
     }

axum/src/extract/multipart.rs

@@ -146,23 +146,27 @@ impl Field<'_> {
     /// The field name found in the
     /// [`Content-Disposition`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition)
     /// header.
+    #[must_use]
     pub fn name(&self) -> Option<&str> {
         self.inner.name()
     }
 
     /// The file name found in the
     /// [`Content-Disposition`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition)
     /// header.
+    #[must_use]
     pub fn file_name(&self) -> Option<&str> {
         self.inner.file_name()
     }
 
     /// Get the [content type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type) of the field.
+    #[must_use]
     pub fn content_type(&self) -> Option<&str> {
         self.inner.content_type().map(|m| m.as_ref())
     }
 
     /// Get a map of headers as [`HeaderMap`].
+    #[must_use]
     pub fn headers(&self) -> &HeaderMap {
         self.inner.headers()
     }
@@ -238,11 +242,13 @@ impl MultipartError {
     }
 
     /// Get the response body text used for this rejection.
+    #[must_use]
     pub fn body_text(&self) -> String {
         self.source.to_string()
     }
 
     /// Get the status code used for this rejection.
+    #[must_use]
     pub fn status(&self) -> http::StatusCode {
         status_code_from_multer_error(&self.source)
     }

axum/src/extract/nested_path.rs

@@ -41,6 +41,7 @@ pub struct NestedPath(Arc<str>);
 
 impl NestedPath {
     /// Returns a `str` representation of the path.
+    #[must_use]
     pub fn as_str(&self) -> &str {
         &self.0
     }

axum/src/extract/path/mod.rs

@@ -407,16 +407,19 @@ pub struct FailedToDeserializePathParams(PathDeserializationError);
 
 impl FailedToDeserializePathParams {
     /// Get a reference to the underlying error kind.
+    #[must_use]
     pub fn kind(&self) -> &ErrorKind {
         &self.0.kind
     }
 
     /// Convert this error into the underlying error kind.
+    #[must_use]
     pub fn into_kind(self) -> ErrorKind {
         self.0.kind
     }
 
     /// Get the response body text used for this rejection.
+    #[must_use]
     pub fn body_text(&self) -> String {
         match self.0.kind {
             ErrorKind::Message(_)
@@ -432,6 +435,7 @@ impl FailedToDeserializePathParams {
     }
 
     /// Get the status code used for this rejection.
+    #[must_use]
     pub fn status(&self) -> StatusCode {
         match self.0.kind {
             ErrorKind::Message(_)
@@ -523,6 +527,7 @@ where
 
 impl RawPathParams {
     /// Get an iterator over the path parameters.
+    #[must_use]
     pub fn iter(&self) -> RawPathParamsIter<'_> {
         self.into_iter()
     }
@@ -561,11 +566,13 @@ pub struct InvalidUtf8InPathParam {
 
 impl InvalidUtf8InPathParam {
     /// Get the response body text used for this rejection.
+    #[must_use]
     pub fn body_text(&self) -> String {
         self.to_string()
     }
 
     /// Get the status code used for this rejection.
+    #[must_use]
     pub fn status(&self) -> StatusCode {
         StatusCode::BAD_REQUEST
     }

axum/src/extract/ws.rs

@@ -580,6 +580,7 @@ pub struct Utf8Bytes(ts::Utf8Bytes);
 impl Utf8Bytes {
     /// Creates from a static str.
     #[inline]
+    #[must_use]
     pub const fn from_static(str: &'static str) -> Self {
         Self(ts::Utf8Bytes::from_static(str))
     }

axum/src/response/redirect.rs

@@ -56,11 +56,13 @@ impl Redirect {
     }
 
     /// Returns the HTTP status code of the `Redirect`.
+    #[must_use]
     pub fn status_code(&self) -> StatusCode {
         self.status_code
     }
 
     /// Returns the `Redirect`'s URI.
+    #[must_use]
     pub fn location(&self) -> &str {
         &self.location
     }

axum/src/routing/method_filter.rs

@@ -58,6 +58,7 @@ impl MethodFilter {
     }
 
     /// Performs the OR operation between the [`MethodFilter`] in `self` with `other`.
+    #[must_use]
     pub const fn or(self, other: Self) -> Self {
         Self(self.0 | other.0)
     }

axum/src/routing/method_routing.rs

@@ -703,6 +703,7 @@ impl MethodRouter<(), Infallible> {
     /// ```
     ///
     /// [`MakeService`]: tower::make::MakeService
+    #[must_use]
     pub fn into_make_service(self) -> IntoMakeService<Self> {
         IntoMakeService::new(self.with_state(()))
     }
@@ -736,6 +737,7 @@ impl MethodRouter<(), Infallible> {
     /// [`MakeService`]: tower::make::MakeService
     /// [`Router::into_make_service_with_connect_info`]: crate::routing::Router::into_make_service_with_connect_info
     #[cfg(feature = "tokio")]
+    #[must_use]
     pub fn into_make_service_with_connect_info<C>(self) -> IntoMakeServiceWithConnectInfo<Self, C> {
         IntoMakeServiceWithConnectInfo::new(self.with_state(()))
     }