error[E0308]: mismatched types
  --> $DIR/estr-subtyping.rs:10:15
   |
LL |    wants_uniq(x);
   |               ^
   |               |
   |               expected struct `String`, found `&str`
   |               help: try using a conversion method: `x.to_string()`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.