to contain String

src/main.rs

@@ -101,8 +101,6 @@ fn main() -> Result<ExitCode> {
         info_file.final_message.unwrap_or_default(),
     )?;
 
-    let replacer = UrlReplacer::new(&args.base_url);
-
     // Show the welcome message if the state file doesn't exist yet.
     if let Some(welcome_message) = info_file.welcome_message {
         match state_file_status {
@@ -189,7 +187,12 @@ fn main() -> Result<ExitCode> {
             }
 
             let hint = app_state.current_exercise().hint;
+            if let Some(base_url) = args.base_url {
+                let replacer = UrlReplacer::new(base_url);
                 println!("{}", replacer.replace(hint));
+            } else {
+                println!("{}", hint);
+            };
         }
         // Handled in an earlier match.
         Some(Subcommands::Init | Subcommands::Dev(_)) => (),

src/url_replacer.rs

@@ -1,21 +1,17 @@
-pub struct UrlReplacer <'a> {
-    base_url: &'a Option<String>
+pub struct UrlReplacer {
+    base_url: String
 }
 
 const EN_BASE_URL: &str = "https://doc.rust-lang.org/book";
 
-impl <'a> UrlReplacer <'a> {
-    pub fn new(base_url: &'a Option<String>) -> Self {
+impl UrlReplacer {
+    pub fn new(base_url: String) -> Self {
         Self {
             base_url
         }
     }
 
     pub fn replace(&self, hint: &str) -> String {
-        if let Some(base_url) = self.base_url {
-            hint.replace(EN_BASE_URL, base_url)
-        } else {
-            hint.to_owned()
-        }
+        hint.replace(EN_BASE_URL, &self.base_url)
     }
 }