error[E0308]: mismatched types
 --> test.rs:4:17
  |
4 |     let _: () = 1;
  |                 ^ expected (), found integer
  |
  = note: expected type `()`
             found type `{integer}`

error[E0308]: mismatched types
 --> test.rs:5:17
  |
5 |     let _: () = x;
  |                 ^ expected (), found i32
  |
  = note: expected type `()`
             found type `i32`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.