error[E0381]: assign to part of possibly uninitialized variable: `s`
  --> $DIR/borrowck-union-uninitialized.rs:13:9
   |
LL |         s.a = 0;
   |         ^^^^^^^ use of possibly uninitialized `s`

error[E0381]: assign to part of possibly uninitialized variable: `u`
  --> $DIR/borrowck-union-uninitialized.rs:14:9
   |
LL |         u.a = 0;
   |         ^^^^^^^ use of possibly uninitialized `u`

error: aborting due to 2 previous errors

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