error[E0599]: no method named `poll` found for struct `Sleep` in the current scope
  --> $DIR/pin-needed-to-poll.rs:42:20
   |
LL | struct Sleep;
   | ------------ method `poll` not found for this struct
...
LL |         self.sleep.poll(cx)
   |                    ^^^^ method not found in `Sleep`
  --> $SRC_DIR/core/src/future/future.rs:LL:COL
   |
   = note: the method is available for `Pin<&mut Sleep>` here
   |
help: consider wrapping the receiver expression with the appropriate type
   |
LL |         Pin::new(&mut self.sleep).poll(cx)
   |         +++++++++++++           +

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.