error[E0383]: partial reinitialization of uninitialized structure `x.0`
  --> $DIR/borrowck-partial-reinit-4.rs:17:5
   |
LL |     (x.0).0 = Some(Test);
   |     ^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0383`.