error: task functions must not have `self` arguments
 --> tests/ui/self_ref.rs:6:15
  |
6 | async fn task(&mut self) {}
  |               ^^^^^^^^^

error: `self` parameter is only allowed in associated functions
 --> tests/ui/self_ref.rs:6:15
  |
6 | async fn task(&mut self) {}
  |               ^^^^^^^^^ not semantically valid as function parameter
  |
  = note: associated functions are those in `impl` or `trait` definitions