| error[E0369]: cannot add `&str` to `&String` | |
| --> $DIR/str-concat-on-double-ref.rs:4:15 | |
| | | |
| LL | let c = a + b; | |
| | - ^ - &str | |
| | | | | |
| | | `+` cannot be used to concatenate two `&str` strings | |
| | &String | |
| | | |
| = note: string concatenation requires an owned `String` on the left | |
| help: create an owned `String` from a string reference | |
| | | |
| LL | let c = a.to_owned() + b; | |
| | +++++++++++ | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0369`. |