error: expected one of `!`, `(`, `+`, `,`, `::`, `:`, `<`, `=`, or `>`, found `)`
  --> $DIR/issue-62660.rs:7:38
   |
LL |     pub fn foo(_: i32, self: Box<Self) {}
   |                                      ^ expected one of 9 possible tokens

error: aborting due to previous error