error[E0369]: binary operation `^` cannot be applied to type `std::string::String`
  --> $DIR/binop-bitxor-str.rs:3:37
   |
LL | fn main() { let x = "a".to_string() ^ "b".to_string(); }
   |                     --------------- ^ --------------- std::string::String
   |                     |
   |                     std::string::String
   |
   = note: an implementation of `std::ops::BitXor` might be missing for `std::string::String`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0369`.