error[E0539]: malformed `deprecated` attribute input
  --> $DIR/E0539.rs:2:1
   |
LL | #[deprecated(since = b"1.29", note = "hi")]
   | ^^^^^^^^^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^^^^^
   |                      |
   |                      help: consider removing the prefix
   |
   = note: expected a normal string literal, not a byte string literal

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0539`.