error[E0404]: expected trait, found builtin type `i8`
 --> src/main.rs:5:12
  |
5 |     let x: i8 += 14;
  |            ^^ not a trait

warning: trait objects without an explicit `dyn` are deprecated
 --> src/main.rs:5:12
  |
5 |     let x: i8 += 14;
  |            ^^^^ help: use `dyn`: `dyn i8 +`
  |
  = note: `#[warn(bare_trait_objects)]` on by default

error: aborting due to previous error