enable let_underscore_untyped lint

Cargo.toml

@@ -172,6 +172,7 @@ large_include_file = "warn"
 large_stack_arrays = "warn"
 large_stack_frames = "warn"
 large_types_passed_by_value = "warn"
+let_underscore_untyped = "warn"
 let_unit_value = "warn"
 linkedlist = "warn"
 lossy_float_literal = "warn"
@@ -255,7 +256,6 @@ zero_sized_map_values = "warn"
 
 # TODO(emilk): enable more of these lints:
 iter_over_hash_type = "allow"
-let_underscore_untyped = "allow"
 missing_assert_message = "allow"
 should_panic_without_expect = "allow"
 too_many_lines = "allow"

crates/ecolor/src/hex_color_macro.rs

@@ -24,11 +24,11 @@
 /// If the literal string has the wrong format, the code does not compile.
 ///
 /// ```compile_fail
-/// let _ = ecolor::hex_color!("#abc");
+/// _ = ecolor::hex_color!("#abc");
 /// ```
 ///
 /// ```compile_fail
-/// let _ = ecolor::hex_color!("#20212x");
+/// _ = ecolor::hex_color!("#20212x");
 /// ```
 ///
 /// The macro cannot be used in a `const` context.

crates/eframe/src/web/web_runner.rs

@@ -213,7 +213,7 @@ impl WebRunner {
                 // We can paint now, so clear the animation frame.
                 // This drops the `closure` and allows another
                 // animation frame to be scheduled
-                let _ = runner_ref.frame.take();
+                _ = runner_ref.frame.take();
                 events::paint_and_schedule(&runner_ref)
             }
         });

crates/egui/src/lib.rs

@@ -668,7 +668,7 @@ pub enum WidgetType {
 pub fn __run_test_ctx(mut run_ui: impl FnMut(&Context)) {
     let ctx = Context::default();
     ctx.set_fonts(FontDefinitions::empty()); // prevent fonts from being loaded (save CPU time)
-    let _ = ctx.run(Default::default(), |ctx| {
+    _ = ctx.run(Default::default(), |ctx| {
         run_ui(ctx);
     });
 }
@@ -677,7 +677,7 @@ pub fn __run_test_ctx(mut run_ui: impl FnMut(&Context)) {
 pub fn __run_test_ui(add_contents: impl Fn(&mut Ui)) {
     let ctx = Context::default();
     ctx.set_fonts(FontDefinitions::empty()); // prevent fonts from being loaded (save CPU time)
-    let _ = ctx.run(Default::default(), |ctx| {
+    _ = ctx.run(Default::default(), |ctx| {
         crate::CentralPanel::default().show(ctx, |ui| {
             add_contents(ui);
         });

crates/egui/src/load.rs

@@ -303,7 +303,7 @@ pub trait BytesLoader {
     /// Implementations may use this to perform work at the end of a frame,
     /// such as evicting unused entries from a cache.
     fn end_pass(&self, frame_index: usize) {
-        let _ = frame_index;
+        _ = frame_index;
     }
 
     /// If the loader caches any data, this should return the size of that cache.
@@ -370,7 +370,7 @@ pub trait ImageLoader {
     /// Implementations may use this to perform work at the end of a pass,
     /// such as evicting unused entries from a cache.
     fn end_pass(&self, frame_index: usize) {
-        let _ = frame_index;
+        _ = frame_index;
     }
 
     /// If the loader caches any data, this should return the size of that cache.
@@ -508,7 +508,7 @@ pub trait TextureLoader {
     /// Implementations may use this to perform work at the end of a pass,
     /// such as evicting unused entries from a cache.
     fn end_pass(&self, frame_index: usize) {
-        let _ = frame_index;
+        _ = frame_index;
     }
 
     /// If the loader caches any data, this should return the size of that cache.

crates/egui/src/response.rs

@@ -1078,7 +1078,7 @@ impl Response {
         });
         #[cfg(not(feature = "accesskit"))]
         {
-            let _ = id;
+            _ = id;
         }
 
         self

crates/egui/src/viewport.rs

@@ -1153,7 +1153,7 @@ impl ViewportOutput {
 
         self.parent = parent;
         self.class = class;
-        let _ = self.builder.patch(builder); // we ignore the returned command, because `self.builder` will be the basis of a new patch
+        _ = self.builder.patch(builder); // we ignore the returned command, because `self.builder` will be the basis of a new patch
         self.viewport_ui_cb = viewport_ui_cb;
         self.commands.append(&mut commands);
         self.repaint_delay = self.repaint_delay.min(repaint_delay);

crates/egui/tests/accesskit.rs

@@ -106,9 +106,9 @@ fn multiple_disabled_widgets() {
     let output = accesskit_output_single_egui_frame(|ctx| {
         CentralPanel::default().show(ctx, |ui| {
             ui.add_enabled_ui(false, |ui| {
-                let _ = ui.button("Button 1");
-                let _ = ui.button("Button 2");
-                let _ = ui.button("Button 3");
+                _ = ui.button("Button 1");
+                _ = ui.button("Button 2");
+                _ = ui.button("Button 3");
             })
         });
     });

crates/egui_demo_lib/benches/benchmark.rs

@@ -51,7 +51,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
 
     {
         let ctx = egui::Context::default();
-        let _ = ctx.run(RawInput::default(), |ctx| {
+        _ = ctx.run(RawInput::default(), |ctx| {
             egui::CentralPanel::default().show(ctx, |ui| {
                 c.bench_function("label &str", |b| {
                     b.iter(|| {

crates/egui_demo_lib/src/demo/about.rs

@@ -67,7 +67,7 @@ fn about_immediate_mode(ui: &mut egui::Ui) {
     ui.horizontal_wrapped(|ui| {
             ui.spacing_mut().item_spacing.x = 0.0;
             ui.label("Immediate mode is a GUI paradigm that lets you create a GUI with less code and simpler control flow. For example, this is how you create a ");
-            let _ = ui.small_button("button");
+            _ = ui.small_button("button");
             ui.label(" in egui:");
         });
 

crates/egui_demo_lib/src/demo/context_menu.rs

@@ -50,28 +50,28 @@ impl ContextMenus {
                 if ui.button("Open…").clicked() {
                     ui.close_menu();
                 }
-                let _ = ui.button("Item");
+                _ = ui.button("Item");
             });
             ui.menu_button("SubMenu", |ui| {
                 if ui.button("Open…").clicked() {
                     ui.close_menu();
                 }
-                let _ = ui.button("Item");
+                _ = ui.button("Item");
             });
-            let _ = ui.button("Item");
+            _ = ui.button("Item");
             if ui.button("Open…").clicked() {
                 ui.close_menu();
             }
         });
         ui.menu_button("SubMenu", |ui| {
-            let _ = ui.button("Item1");
-            let _ = ui.button("Item2");
-            let _ = ui.button("Item3");
-            let _ = ui.button("Item4");
+            _ = ui.button("Item1");
+            _ = ui.button("Item2");
+            _ = ui.button("Item3");
+            _ = ui.button("Item4");
             if ui.button("Open…").clicked() {
                 ui.close_menu();
             }
         });
-        let _ = ui.button("Very long text for this item that should be wrapped");
+        _ = ui.button("Very long text for this item that should be wrapped");
     }
 }

crates/egui_demo_lib/src/demo/misc_demo_window.rs

@@ -217,7 +217,7 @@ fn label_ui(ui: &mut egui::Ui) {
             );
 
             ui.label("You can mix in other widgets into text, like");
-            let _ = ui.small_button("this button");
+            _ = ui.small_button("this button");
             ui.label(".");
 
             ui.label("The default font supports all latin and cyrillic characters (ИÅđ…), common math symbols (∫√∞²⅓…), and many emojis (💓🌟🖩…).")

crates/egui_demo_lib/src/demo/tests/cursor_test.rs

@@ -19,7 +19,7 @@ impl crate::View for CursorTest {
         ui.vertical_centered_justified(|ui| {
             ui.heading("Hover to switch cursor icon:");
             for &cursor_icon in &egui::CursorIcon::ALL {
-                let _ = ui
+                _ = ui
                     .button(format!("{cursor_icon:?}"))
                     .on_hover_cursor(cursor_icon);
             }

crates/egui_demo_lib/src/demo/tests/id_test.rs

@@ -44,8 +44,8 @@ impl crate::View for IdTest {
             (and if it is, the window will have a new layout, and the slider will end up somewhere else, and so aborting the interaction probably makes sense).");
 
         ui.label("So these buttons have automatic Id:s, and therefore there is no name clash:");
-        let _ = ui.button("Button");
-        let _ = ui.button("Button");
+        _ = ui.button("Button");
+        _ = ui.button("Button");
 
         ui.vertical_centered(|ui| {
             ui.add(crate::egui_github_link_file!());

crates/egui_demo_lib/src/demo/tests/layout_test.rs

@@ -180,5 +180,5 @@ fn demo_ui(ui: &mut Ui) {
     let mut dummy = false;
     ui.checkbox(&mut dummy, "checkbox");
     ui.radio_value(&mut dummy, false, "radio");
-    let _ = ui.button("button");
+    _ = ui.button("button");
 }

crates/egui_extras/src/loaders.rs

@@ -98,7 +98,7 @@ pub fn install_image_loaders(ctx: &egui::Context) {
     ))]
     log::warn!("`install_image_loaders` was called, but no loaders are enabled");
 
-    let _ = ctx;
+    _ = ctx;
 }
 
 #[cfg(not(target_arch = "wasm32"))]

crates/egui_extras/src/loaders/ehttp_loader.rs

@@ -105,7 +105,7 @@ impl BytesLoader for EhttpLoader {
     }
 
     fn forget(&self, uri: &str) {
-        let _ = self.cache.lock().remove(uri);
+        _ = self.cache.lock().remove(uri);
     }
 
     fn forget_all(&self) {

crates/egui_extras/src/loaders/file_loader.rs

@@ -108,7 +108,7 @@ impl BytesLoader for FileLoader {
     }
 
     fn forget(&self, uri: &str) {
-        let _ = self.cache.lock().remove(uri);
+        _ = self.cache.lock().remove(uri);
     }
 
     fn forget_all(&self) {

crates/egui_extras/src/loaders/gif_loader.rs

@@ -114,7 +114,7 @@ impl ImageLoader for GifLoader {
     }
 
     fn forget(&self, uri: &str) {
-        let _ = self.cache.lock().remove(uri);
+        _ = self.cache.lock().remove(uri);
     }
 
     fn forget_all(&self) {

crates/egui_extras/src/loaders/image_loader.rs

@@ -80,7 +80,7 @@ impl ImageLoader for ImageCrateLoader {
     }
 
     fn forget(&self, uri: &str) {
-        let _ = self.cache.lock().remove(uri);
+        _ = self.cache.lock().remove(uri);
     }
 
     fn forget_all(&self) {

crates/epaint/src/mutex.rs

@@ -431,13 +431,13 @@ mod tests_rwlock {
         let other_thread1 = {
             let one = Arc::clone(&one);
             std::thread::spawn(move || {
-                let _ = one.write();
+                _ = one.write();
             })
         };
         let other_thread2 = {
             let one = Arc::clone(&one);
             std::thread::spawn(move || {
-                let _ = one.read();
+                _ = one.read();
             })
         };
         std::thread::sleep(Duration::from_millis(200));

examples/hello_world_par/src/main.rs

@@ -69,7 +69,7 @@ fn new_worker(
             let mut state = ThreadState::new(thread_nr);
             while let Ok(ctx) = show_rc.recv() {
                 state.show(&ctx);
-                let _ = on_done_tx.send(());
+                _ = on_done_tx.send(());
             }
         })
         .expect("failed to spawn thread");
@@ -124,11 +124,11 @@ impl eframe::App for MyApp {
         });
 
         for (_handle, show_tx) in &self.threads {
-            let _ = show_tx.send(ctx.clone());
+            _ = show_tx.send(ctx.clone());
         }
 
         for _ in 0..self.threads.len() {
-            let _ = self.on_done_rc.recv();
+            _ = self.on_done_rc.recv();
         }
     }
 }

tests/test_size_pass/src/main.rs

@@ -45,7 +45,7 @@ fn main() -> eframe::Result {
                     );
                     ui.label("Hover for interactive tooltip").on_hover_ui(|ui| {
                         ui.label("This tooltip has a button:");
-                        let _ = ui.button("Clicking me does nothing");
+                        _ = ui.button("Clicking me does nothing");
                     });
                 });
             });
@@ -64,9 +64,9 @@ fn main() -> eframe::Result {
 
             ui.label("The menu should be as wide as the widest button");
             ui.menu_button("Click for menu", |ui| {
-                let _ = ui.button("Narrow").clicked();
-                let _ = ui.button("Very wide text").clicked();
-                let _ = ui.button("Narrow").clicked();
+                _ = ui.button("Narrow").clicked();
+                _ = ui.button("Very wide text").clicked();
+                _ = ui.button("Narrow").clicked();
             });
 
             ui.label("Hover for tooltip").on_hover_ui(|ui| {

tests/test_viewports/src/main.rs

@@ -12,7 +12,7 @@ pub const DRAG_AND_DROP_TEST: bool = false;
 fn main() {
     env_logger::init(); // Use `RUST_LOG=debug` to see logs.
 
-    let _ = eframe::run_native(
+    _ = eframe::run_native(
         "Viewports",
         eframe::NativeOptions {
             viewport: egui::ViewportBuilder::default().with_inner_size([450.0, 400.0]),