error[E0277]: the size for values of type `str` cannot be known at compilation time
  --> $DIR/union-unsized.rs:4:5
   |
LL |     a: str,
   |     ^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `str`
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: no field of a union may have a dynamically sized type

error[E0277]: the size for values of type `str` cannot be known at compilation time
  --> $DIR/union-unsized.rs:12:5
   |
LL |     b: str,
   |     ^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `str`
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: no field of a union may have a dynamically sized type

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.