error[E0748]: unterminated raw string
  --> $DIR/raw-string-2.rs:2:13
   |
LL |     let x = r###"here's a long string"# "# "##;
   |             ^ unterminated raw string       -- help: consider terminating the string here: `###`
   |
   = note: this raw string should be terminated with `"###`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0748`.