Minor clippy fixes (clippy::format_push_string)

egui_demo_app/src/wrap_app.rs

@@ -303,15 +303,16 @@ impl WrapApp {
 
     fn ui_file_drag_and_drop(&mut self, ctx: &egui::Context) {
         use egui::*;
+        use std::fmt::Write as _;
 
         // Preview hovering files:
         if !ctx.input().raw.hovered_files.is_empty() {
             let mut text = "Dropping files:\n".to_owned();
             for file in &ctx.input().raw.hovered_files {
                 if let Some(path) = &file.path {
-                    text += &format!("\n{}", path.display());
+                    write!(text, "\n{}", path.display()).ok();
                 } else if !file.mime.is_empty() {
-                    text += &format!("\n{}", file.mime);
+                    write!(text, "\n{}", file.mime).ok();
                 } else {
                     text += "\n???";
                 }
@@ -351,7 +352,7 @@ impl WrapApp {
                             "???".to_owned()
                         };
                         if let Some(bytes) = &file.bytes {
-                            info += &format!(" ({} bytes)", bytes.len());
+                            write!(info, " ({} bytes)", bytes.len()).ok();
                         }
                         ui.label(info);
                     }

egui_demo_lib/src/demo/tests.rs

@@ -344,21 +344,25 @@ impl super::View for InputTest {
             egui::PointerButton::Extra1,
             egui::PointerButton::Extra2,
         ] {
+            use std::fmt::Write as _;
+
             if response.clicked_by(button) {
-                new_info += &format!("Clicked by {:?} button\n", button);
+                writeln!(new_info, "Clicked by {:?} button", button).ok();
             }
             if response.double_clicked_by(button) {
-                new_info += &format!("Double-clicked by {:?} button\n", button);
+                writeln!(new_info, "Double-clicked by {:?} button", button).ok();
             }
             if response.triple_clicked_by(button) {
-                new_info += &format!("Triple-clicked by {:?} button\n", button);
+                writeln!(new_info, "Triple-clicked by {:?} button", button).ok();
             }
             if response.dragged_by(button) {
-                new_info += &format!(
+                writeln!(
-                    "Dragged by {:?} button, delta: {:?}\n",
+                    new_info,
+                    "Dragged by {:?} button, delta: {:?}",
                     button,
                     response.drag_delta()
-                );
+                )
+                .ok();
             }
         }
         if !new_info.is_empty() {

epaint/src/textures.rs

@@ -200,22 +200,26 @@ impl TexturesDelta {
 
 impl std::fmt::Debug for TexturesDelta {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use std::fmt::Write as _;
+
         let mut debug_struct = f.debug_struct("TexturesDelta");
         if !self.set.is_empty() {
             let mut string = String::new();
             for (tex_id, delta) in &self.set {
                 let size = delta.image.size();
                 if let Some(pos) = delta.pos {
-                    string += &format!(
+                    write!(
+                        string,
                         "{:?} partial ([{} {}] - [{} {}]), ",
                         tex_id,
                         pos[0],
                         pos[1],
                         pos[0] + size[0],
                         pos[1] + size[1]
-                    );
+                    )
+                    .ok();
                 } else {
-                    string += &format!("{:?} full {}x{}, ", tex_id, size[0], size[1]);
+                    write!(string, "{:?} full {}x{}, ", tex_id, size[0], size[1]).ok();
                 }
             }
             debug_struct.field("set", &string);

examples/file_dialog/src/main.rs

@@ -52,7 +52,8 @@ impl eframe::App for MyApp {
                             "???".to_owned()
                         };
                         if let Some(bytes) = &file.bytes {
-                            info += &format!(" ({} bytes)", bytes.len());
+                            use std::fmt::Write as _;
+                            write!(info, " ({} bytes)", bytes.len()).ok();
                         }
                         ui.label(info);
                     }
@@ -72,14 +73,15 @@ impl eframe::App for MyApp {
 /// Preview hovering files:
 fn preview_files_being_dropped(ctx: &egui::Context) {
     use egui::*;
+    use std::fmt::Write as _;
 
     if !ctx.input().raw.hovered_files.is_empty() {
         let mut text = "Dropping files:\n".to_owned();
         for file in &ctx.input().raw.hovered_files {
             if let Some(path) = &file.path {
-                text += &format!("\n{}", path.display());
+                write!(text, "\n{}", path.display()).ok();
             } else if !file.mime.is_empty() {
-                text += &format!("\n{}", file.mime);
+                write!(text, "\n{}", file.mime).ok();
             } else {
                 text += "\n???";
             }