error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> $DIR/union.rs:30:20
   |
LL |         Foo { bar: _a } => {},
   |                    ^^ access to union field
   |
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> $DIR/union.rs:32:11
   |
LL |     match foo {
   |           ^^^ access to union field
   |
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0133`.