Fix clippy lints for all crates and features

... and check those in CI as well!

examples/todos/src/main.rs

@@ -168,7 +168,7 @@ impl Application for Todos {
                 .size(30)
                 .on_submit(Message::CreateTask);
 
-                let controls = controls.view(&tasks, *filter);
+                let controls = controls.view(tasks, *filter);
                 let filtered_tasks =
                     tasks.iter().filter(|task| filter.matches(task));
 
@@ -493,15 +493,15 @@ struct SavedState {
 
 #[derive(Debug, Clone)]
 enum LoadError {
-    FileError,
-    FormatError,
+    File,
+    Format,
 }
 
 #[derive(Debug, Clone)]
 enum SaveError {
-    FileError,
-    WriteError,
-    FormatError,
+    File,
+    Write,
+    Format,
 }
 
 #[cfg(not(target_arch = "wasm32"))]
@@ -512,7 +512,7 @@ impl SavedState {
         {
             project_dirs.data_dir().into()
         } else {
-            std::env::current_dir().unwrap_or(std::path::PathBuf::new())
+            std::env::current_dir().unwrap_or_default()
         };
 
         path.push("todos.json");
@@ -527,37 +527,37 @@ impl SavedState {
 
         let mut file = async_std::fs::File::open(Self::path())
             .await
-            .map_err(|_| LoadError::FileError)?;
+            .map_err(|_| LoadError::File)?;
 
         file.read_to_string(&mut contents)
             .await
-            .map_err(|_| LoadError::FileError)?;
+            .map_err(|_| LoadError::File)?;
 
-        serde_json::from_str(&contents).map_err(|_| LoadError::FormatError)
+        serde_json::from_str(&contents).map_err(|_| LoadError::Format)
     }
 
     async fn save(self) -> Result<(), SaveError> {
         use async_std::prelude::*;
 
         let json = serde_json::to_string_pretty(&self)
-            .map_err(|_| SaveError::FormatError)?;
+            .map_err(|_| SaveError::Format)?;
 
         let path = Self::path();
 
         if let Some(dir) = path.parent() {
             async_std::fs::create_dir_all(dir)
                 .await
-                .map_err(|_| SaveError::FileError)?;
+                .map_err(|_| SaveError::File)?;
         }
 
         {
             let mut file = async_std::fs::File::create(path)
                 .await
-                .map_err(|_| SaveError::FileError)?;
+                .map_err(|_| SaveError::File)?;
 
             file.write_all(json.as_bytes())
                 .await
-                .map_err(|_| SaveError::WriteError)?;
+                .map_err(|_| SaveError::Write)?;
         }
 
         // This is a simple way to save at most once every couple seconds