$ cargo run
   Compiling closure-example v0.1.0 (file:///projects/closure-example)
error[E0308]: mismatched types
 --> src/main.rs:5:29
  |
5 |     let n = example_closure(5);
  |                             ^
  |                             |
  |                             expected struct `String`, found integer
  |                             help: try using a conversion method: `5.to_string()`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.
error: could not compile `closure-example`

To learn more, run the command again with --verbose.