Fix some launch error handling in tests and examples.

Author: jebrosen

core/lib/src/error.rs

@@ -51,17 +51,26 @@ pub enum LaunchErrorKind {
 /// as inspected; a subsequent `drop` of the value will _not_ result in a panic.
 /// The following snippet illustrates this:
 ///
-// TODO.async This isn't true any more, as `.launch()` now returns a
-// `Result<(), crate::error::Error>`, which could also be a runtime error.
-/// ```rust,ignore
+/// ```rust
+/// use rocket::error::Error;
+///
 /// # if false {
-/// let error = rocket::ignite().launch();
+/// if let Err(error) = rocket::ignite().launch() {
+///     match error {
+///         Error::Launch(error) => {
+///             // This case is only reached if launching failed. This println "inspects" the error.
+///             println!("Launch failed! Error: {}", error);
 ///
-/// // This line is only reached if launching failed. This "inspects" the error.
-/// println!("Launch failed! Error: {}", error);
+///             // This call to drop (explicit here for demonstration) will do nothing.
+///             drop(error);
+///         }
+///         Error::Run(error) => {
+///             // This case is reached if launching succeeds, but the server had a fatal error later
+///             println!("Server failed! Error: {}", error);
+///         }
+///     }
+/// }
 ///
-/// // This call to drop (explicit here for demonstration) will do nothing.
-/// drop(error);
 /// # }
 /// ```
 ///

examples/errors/src/main.rs

@@ -19,13 +19,14 @@ fn not_found(req: &rocket::Request<'_>) -> content::Html<String> {
 }
 
 fn main() {
-    let e = rocket::ignite()
+    let result = rocket::ignite()
         // .mount("/", routes![hello, hello]) // uncoment this to get an error
         .mount("/", routes![hello])
         .register(catchers![not_found])
         .launch();
 
-    println!("Whoops! Rocket didn't launch!");
-    // TODO.async Uncomment the following line once `.launch()`'s error type is determined.
-    // println!("This went wrong: {}", e);
+    if let Err(e) = result {
+        println!("Whoops! Rocket didn't launch!");
+        println!("This went wrong: {:?}", e);
+    };
 }