error[E0308]: mismatched types
  --> $DIR/main.rs:12:18
   |
LL |       let x: u32 = ( //~ ERROR mismatched types
   |  __________________^
LL | |     );
   | |_____^ expected u32, found ()
   |
   = note: expected type `u32`
              found type `()`

error: aborting due to previous error

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