Use the NotFound variant of the IO error

Author: mo8it

src/main.rs

@@ -91,23 +91,22 @@ fn main() {
         println!("\n{WELCOME}\n");
     }
 
-    if !Path::new("info.toml").exists() {
-        println!(
-            "{} must be run from the rustlings directory",
-            std::env::current_exe().unwrap().to_str().unwrap()
-        );
-        println!("Try `cd rustlings/`!");
-        std::process::exit(1);
-    }
-
     if !rustc_exists() {
         println!("We cannot find `rustc`.");
         println!("Try running `rustc --version` to diagnose your problem.");
         println!("For instructions on how to install Rust, check the README.");
         std::process::exit(1);
     }
 
-    let info_file = fs::read_to_string("info.toml").unwrap();
+    let info_file = fs::read_to_string("info.toml").unwrap_or_else(|e| {
+        match e.kind() {
+            io::ErrorKind::NotFound => println!(
+                "The program must be run from the rustlings directory\nTry `cd rustlings/`!",
+            ),
+            _ => println!("Failed to read the info.toml file: {e}"),
+        }
+        std::process::exit(1);
+    });
     let exercises = toml_edit::de::from_str::<ExerciseList>(&info_file)
         .unwrap()
         .exercises;