error: to use a constant of type `Vec<u8>` in a pattern, `Vec<u8>` must be annotated with `#[derive(PartialEq, Eq)]`
  --> $DIR/issue-115599.rs:5:12
   |
LL |     if let CONST_STRING = empty_str {}
   |            ^^^^^^^^^^^^
   |
   = note: the traits must be derived, manual `impl`s are not sufficient
   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details

error: aborting due to 1 previous error