1 error[E0369]: binary operation `+` cannot be applied to type `&str`
2 --> $DIR/issue-47377.rs:4:14
4 LL | let _a = b + ", World!";
7 | | `+` can't be used to concatenate two `&str` strings
9 help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
11 LL | let _a = b.to_owned() + ", World!";
14 error: aborting due to previous error
16 For more information about this error, try `rustc --explain E0369`.