Refactor allow to expect (#41586)

Replace `allow` with `expect` lints for `unused`, `unsafe_code`,
`dead_code`, and `non_upper_case_globals`.

Testing: So far just check it compiled on `x86_64-linux` on NixOS. Need
to use the module `system.fontconfig.enable = true;` I think in my NixOS
config.
Part of: #40383 

Searching `allow\(.*\)` for `.rs` files shows the following. for
(total_results:total_files) went from `707:386` to `675:368`, a
reduction of `32:18`.

How many files is too many files per PR? I feel like the 20-30 I have is
too big.

---------

Signed-off-by: Wayne Van Son <waynevanson@gmail.com>

components/allocator/lib.rs

@@ -45,11 +45,11 @@ unsafe extern "C" fn enclosing_size_impl(ptr: *const c_void) -> usize {
     size
 }
 
-#[allow(non_upper_case_globals)]
+#[expect(non_upper_case_globals)]
 #[cfg(feature = "allocation-tracking")]
 pub static enclosing_size: Option<EnclosingSizeFn> = Some(crate::enclosing_size_impl);
 
-#[allow(non_upper_case_globals)]
+#[expect(non_upper_case_globals)]
 #[cfg(not(feature = "allocation-tracking"))]
 pub static enclosing_size: Option<EnclosingSizeFn> = None;
 

components/devtools/actors/frame.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 // TODO: Remove once the actor is used
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 use serde::Serialize;
 use serde_json::{Map, Value};

components/devtools/actors/pause.rs

@@ -5,7 +5,7 @@
 use crate::actor::Actor;
 
 // TODO: Remove once the actor is used.
-#[allow(dead_code)]
+#[expect(dead_code)]
 /// Referenced by `ThreadActor` when replying to `interupt` messages.
 /// <https://searchfox.org/firefox-main/source/devtools/server/actors/thread.js#1699>
 pub struct PauseActor {

components/domobject_derive/lib.rs

@@ -112,7 +112,7 @@ fn expand_dom_object(input: syn::DeriveInput) -> proc_macro2::TokenStream {
         proc_macro2::Span::call_site(),
     );
     let tokens = quote! {
-        #[allow(non_upper_case_globals)]
+        #[expect(non_upper_case_globals)]
         const #dummy_const: () = { #dummy_items };
         #items
     };

components/fonts/lib.rs

@@ -45,7 +45,7 @@ pub(crate) enum EmojiPresentationPreference {
 pub struct FallbackFontSelectionOptions {
     pub(crate) character: char,
     pub(crate) presentation_preference: EmojiPresentationPreference,
-    #[cfg_attr(any(target_os = "android", target_os = "windows"), allow(dead_code))]
+    #[cfg_attr(any(target_os = "android", target_os = "windows"), expect(dead_code))]
     pub(crate) lang: Option<String>,
 }
 

components/script/dom/bindings/buffer_source.rs

@@ -388,7 +388,7 @@ where
         }
     }
     /// <https://streams.spec.whatwg.org/#abstract-opdef-cloneasuint8array>
-    #[allow(unsafe_code)]
+    #[expect(unsafe_code)]
     pub(crate) fn clone_as_uint8_array(
         &self,
         cx: JSContext,

components/script/dom/byteteeunderlyingsource.rs

@@ -431,7 +431,6 @@ impl ByteTeeUnderlyingSource {
     /// Let cancel1Algorithm be the following steps, taking a reason argument
     /// and
     /// Let cancel2Algorithm be the following steps, taking a reason argument
-    #[allow(unsafe_code)]
     pub(crate) fn cancel_algorithm(
         &self,
         reason: SafeHandleValue,
@@ -470,7 +469,7 @@ impl ByteTeeUnderlyingSource {
         }
     }
 
-    #[allow(unsafe_code)]
+    #[expect(unsafe_code)]
     fn resolve_cancel_promise(&self, can_gc: CanGc) {
         // Let compositeReason be ! CreateArrayFromList(« reason_1, reason_2 »).
         let cx = GlobalScope::get_cx();

components/script/dom/commandevent.rs

@@ -43,22 +43,6 @@ impl CommandEvent {
         }
     }
 
-    #[allow(clippy::too_many_arguments)]
-    #[allow(dead_code)]
-    pub(crate) fn new(
-        window: &Window,
-        type_: Atom,
-        bubbles: EventBubbles,
-        cancelable: EventCancelable,
-        source: Option<DomRoot<Element>>,
-        command: DOMString,
-        can_gc: CanGc,
-    ) -> DomRoot<CommandEvent> {
-        Self::new_with_proto(
-            window, None, type_, bubbles, cancelable, source, command, can_gc,
-        )
-    }
-
     #[allow(clippy::too_many_arguments)]
     fn new_with_proto(
         window: &Window,

components/script/dom/webgl/webglrenderingcontext.rs

@@ -2093,7 +2093,7 @@ pub(crate) fn capture_webgl_backtrace() -> WebGLCommandBacktrace {
 }
 
 #[cfg(feature = "webgl_backtrace")]
-#[cfg_attr(feature = "webgl_backtrace", allow(unsafe_code))]
+#[cfg_attr(feature = "webgl_backtrace", expect(unsafe_code))]
 pub(crate) fn capture_webgl_backtrace() -> WebGLCommandBacktrace {
     let bt = Backtrace::new();
     unsafe {

components/script/dom/workers/dedicatedworkerglobalscope.rs

@@ -290,7 +290,7 @@ impl DedicatedWorkerGlobalScope {
         }
     }
 
-    #[allow(unsafe_code, clippy::too_many_arguments)]
+    #[expect(clippy::too_many_arguments)]
     pub(crate) fn new(
         init: WorkerGlobalScopeInit,
         webview_id: WebViewId,

components/script/fetch.rs

@@ -348,7 +348,7 @@ fn queue_deferred_fetch(
 }
 
 /// <https://fetch.spec.whatwg.org/#dom-window-fetchlater>
-#[allow(non_snake_case, unsafe_code)]
+#[expect(non_snake_case, unsafe_code)]
 pub(crate) fn FetchLater(
     window: &Window,
     input: RequestInfo,

components/script_bindings/codegen/codegen.py

@@ -7472,7 +7472,7 @@ class CGNonNamespacedEnum(CGThing):
         entries = [f"{names[0]} = {first}"] + names[1:]
 
         # Append a Last.
-        entries.append(f'#[allow(dead_code)] Last = {first + len(entries)}')
+        entries.append(f'Last = {first + len(entries)}')
 
         # Indent.
         entries = [f'    {e}' for e in entries]
@@ -7900,7 +7900,7 @@ class CGRegisterProxyHandlers(CGThing):
         )
         self.root = CGList([
             CGGeneric(
-                "#[allow(non_upper_case_globals)]\n"
+                "#[expect(non_upper_case_globals)]\n"
                 "pub(crate) mod proxy_handlers {\n"
                 f"{body}}}\n"
             ),

components/servo/tests/common/mod.rs

@@ -88,7 +88,7 @@ pub(crate) struct WebViewDelegateImpl {
     pub(crate) number_of_controls_hidden: Cell<usize>,
 }
 
-#[allow(dead_code)]
+#[allow(dead_code)] // Used by some tests and not others
 impl WebViewDelegateImpl {
     pub(crate) fn reset(&self) {
         self.url_changed.set(false);
@@ -140,7 +140,7 @@ impl WebViewDelegate for WebViewDelegateImpl {
     }
 }
 
-#[allow(dead_code)]
+#[allow(dead_code)] // Used by some tests and not others
 pub(crate) fn evaluate_javascript(
     servo_test: &ServoTest,
     webview: WebView,

ports/servoshell/egl/app.rs

@@ -261,7 +261,7 @@ pub struct App {
     platform_window: Rc<EmbeddedPlatformWindow>,
 }
 
-#[allow(unused)]
+#[expect(unused)]
 impl App {
     pub(super) fn new(init: AppInitOptions) -> Rc<Self> {
         let mut servo_builder = ServoBuilder::default()
@@ -618,7 +618,6 @@ pub(crate) struct XrDiscoveryWebXrRegistry {
 }
 
 #[cfg(feature = "webxr")]
-#[cfg_attr(target_env = "ohos", allow(dead_code))]
 impl XrDiscoveryWebXrRegistry {
     pub(crate) fn new(xr_discovery: Option<servo::webxr::Discovery>) -> Self {
         Self {

ports/servoshell/egl/ohos/mod.rs

@@ -812,7 +812,7 @@ fn register_xcomponent_callbacks(env: &Env, xcomponent: &Object) -> napi_ohos::R
     Ok(())
 }
 
-#[allow(unused)]
+#[expect(unused)]
 fn debug_jsobject(obj: &Object, obj_name: &str) -> napi_ohos::Result<()> {
     let names = obj.get_property_names()?;
     error!("Getting property names of object {obj_name}");
@@ -1053,7 +1053,7 @@ impl Ime for ServoIme {
     }
 }
 
-#[allow(unused)]
+#[expect(unused)]
 impl HostTrait for HostCallbacks {
     fn show_alert(&self, message: String) {
         // forward it to tracing

ports/servoshell/prefs.rs

@@ -42,7 +42,7 @@ pub(crate) static EXPERIMENTAL_PREFS: &[&str] = &[
     "layout_variable_fonts_enabled",
 ];
 
-#[cfg_attr(any(target_os = "android", target_env = "ohos"), allow(dead_code))]
+#[cfg_attr(any(target_os = "android", target_env = "ohos"), expect(dead_code))]
 #[derive(Clone)]
 pub(crate) struct ServoShellPreferences {
     /// A URL to load when starting servoshell.
@@ -213,7 +213,7 @@ pub fn read_prefs_map(txt: &str) -> HashMap<String, PrefValue> {
 }
 
 #[expect(clippy::large_enum_variant)]
-#[cfg_attr(any(target_os = "android", target_env = "ohos"), allow(dead_code))]
+#[cfg_attr(any(target_os = "android", target_env = "ohos"), expect(dead_code))]
 pub(crate) enum ArgumentParsingResult {
     ChromeProcess(Opts, Preferences, ServoShellPreferences),
     ContentProcess(String),

ports/servoshell/test.rs

@@ -222,17 +222,25 @@ fn test_cmd_and_location_bar_url() {
 }
 
 /// Like [test_url] but will produce test for Windows or non Windows using `#[cfg(target_os)]` internally.
+#[cfg(not(target_os = "windows"))]
 fn test_url_any_os(
     input: &str,
     location: &str,
-    #[allow(unused)] if_exists: &str,
-    #[allow(unused)] if_exists_windows: &str,
+    if_exists: &str,
+    _if_exists_windows: &str,
     otherwise: &str,
 ) {
-    #[cfg(not(target_os = "windows"))]
     test_url(input, location, if_exists, otherwise);
+}
 
-    #[cfg(target_os = "windows")]
+#[cfg(target_os = "windows")]
+fn test_url_any_os(
+    input: &str,
+    location: &str,
+    _if_exists: &str,
+    if_exists_windows: &str,
+    otherwise: &str,
+) {
     test_url(input, location, if_exists_windows, otherwise);
 }
 

support/crown/tests/compile-fail/missing_allow_in_rc.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 use std::rc::Rc;
 

support/crown/tests/compile-fail/missing_unrooted_interior.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 #[crown::unrooted_must_root_lint::must_root]
 struct MustBeRooted;

support/crown/tests/compile-fail/missing_unrooted_interior_on_trait.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 trait TypeHolderTrait {
     #[crown::unrooted_must_root_lint::must_root]

support/crown/tests/run-pass/alias-projection-ignored.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 fn main() {}
 

support/crown/tests/run-pass/allow_interior_trait.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 trait TypeHolderTrait {
     #[crown::unrooted_must_root_lint::must_root]

support/crown/tests/run-pass/allow_trait_in_rc.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 use std::rc::Rc;
 

support/crown/tests/run-pass/allowed_interior.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 #[crown::unrooted_must_root_lint::must_root]
 struct MustBeRooted;

support/crown/tests/run-pass/cfg_crown.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 //@rustc-env:RUSTC_BOOTSTRAP=1
 
-#![allow(dead_code)]
+#![expect(dead_code)]
 
 const _: () = assert!(cfg!(crown), "cfg(crown) not set!");
 

third_party/blurmac/src/framework.rs

@@ -9,7 +9,7 @@ use std::os::raw::{c_char, c_int, c_uint};
 
 use objc2::runtime::{BOOL, Class, Object};
 
-#[allow(non_upper_case_globals)]
+#[expect(non_upper_case_globals)]
 pub const nil: *mut Object = 0 as *mut Object;
 
 pub mod ns {