error: prefix `rb` is unknown
  --> $DIR/raw-byte-string-prefix.rs:6:5
   |
LL |     rb"abc";
   |     ^^ unknown prefix
   |
   = note: prefixed identifiers and literals are reserved since Rust 2021
help: use `br` for a raw byte string
   |
LL |     br"abc";
   |     ~~

error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `"abc"`
  --> $DIR/raw-byte-string-prefix.rs:6:7
   |
LL |     rb"abc";
   |       ^^^^^ expected one of 8 possible tokens

error: aborting due to 2 previous errors