error: the type of the `self` parameter does not need to be arbitrary
  --> $DIR/needless_arbitrary_self_type_unfixable.rs:42:31
   |
LL |         fn call_with_mut_self(self: &mut Self) {}
   |                               ^^^^^^^^^^^^^^^ help: consider to change this parameter to: `&'_ mut self`
   |
   = note: `-D clippy::needless-arbitrary-self-type` implied by `-D warnings`

error: aborting due to previous error