cargo clippy --fix generated broken code

[rbtcollins]

Output from clippy.

after fixes were automatically applied the compiler reported errors within these files:

  * examples/threads.rs

This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see 
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag

The following errors were reported:
error[E0277]: the `?` operator can only be used in an async block that returns `Result` or `Option` (or another type that implements `std::ops::FromResidual`)
  --> examples/threads.rs:61:32
   |
60 |       rt.block_on(async {
   |  _______________________-
61 | |         client.register().await?
   | |                                ^ cannot use the `?` operator in an async block that returns `()`
62 | |     })?;
   | |_____- this function should return `Result` or `Option` to accept `?`
   |
   = help: the trait `std::ops::FromResidual<std::result::Result<std::convert::Infallible, std::boxed::Box<dyn std::error::Error + std::marker::Send + std::marker::Sync>>>` is not implemented for `()`

error[E0277]: the `?` operator can only be applied to values that implement `std::ops::Try`
  --> examples/threads.rs:60:5
   |
60 | /     rt.block_on(async {
61 | |         client.register().await?
62 | |     })?;
   | |_______^ the `?` operator cannot be applied to type `()`
   |
   = help: the trait `std::ops::Try` is not implemented for `()`

error: aborting due to 2 previous errors

I would be happy if either the lint didn't fire, or if clippy fixed things with code that works.

Meta

The same error occurs with nightly.

rustc --version --verbose:

rustc 1.64.0 (a55dd71d5 2022-09-19)
rustc 1.66.0-nightly (57f097ea2 2022-10-01)

[Alexendoo]

Could you share the output of running cargo clippy without --fix, or the code this occurred on?

[rbtcollins]

https://github.com/rbtcollins/unleash-client-rust/blob/744b0e64d879b7c681fe14f922bbcf943d8efdf5/examples/threads.rs#L61-L68

[rbtcollins]

The allow was added after this.

    rt.block_on(async {
        if let Err(e) = client.register().await {
            Err(e)
        } else {
            Ok(())
        }
    })?;

for permanence