error[E0381]: assign to part of possibly-uninitialized variable: `x`
  --> $DIR/assign_mutable_fields.rs:9:5
   |
LL |     x.0 = 1;
   |     ^^^^^^^ use of possibly-uninitialized `x`

error[E0381]: assign to part of possibly-uninitialized variable: `x`
  --> $DIR/assign_mutable_fields.rs:17:5
   |
LL |     x.0 = 1;
   |     ^^^^^^^ use of possibly-uninitialized `x`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0381`.