error: expected parameter name, found `*`
  --> $DIR/issue-33413.rs:4:10
   |
LL |     fn f(*, a: u8) -> u8 {}
   |          ^ expected parameter name

error[E0308]: mismatched types
  --> $DIR/issue-33413.rs:4:23
   |
LL |     fn f(*, a: u8) -> u8 {}
   |        -              ^^ expected `u8`, found `()`
   |        |
   |        implicitly returns `()` as its body has no tail or `return` expression
   |
help: consider returning the local binding `a`
   |
LL |     fn f(*, a: u8) -> u8 { a }
   |                            +

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.
