$ cargo run
   Compiling chapter10 v0.1.0 (file:///projects/chapter10)
error[E0597]: `x` does not live long enough
  --> src/main.rs:7:17
   |
7  |             r = &x;
   |                 ^^ borrowed value does not live long enough
8  |         }
   |         - `x` dropped here while still borrowed
9  | 
10 |         println!("r: {}", r);
   |                           - borrow later used here

For more information about this error, try `rustc --explain E0597`.
error: could not compile `chapter10` due to previous error
