|  | warning: the feature `deref_patterns` is incomplete and may not be safe to use and/or cause compiler crashes | 
|  | --> $DIR/ref-mut.rs:1:12 | 
|  | | | 
|  | LL | #![feature(deref_patterns)] | 
|  | |            ^^^^^^^^^^^^^^ | 
|  | | | 
|  | = note: see issue #87121 <https://github.com/rust-lang/rust/issues/87121> for more information | 
|  | = note: `#[warn(incomplete_features)]` on by default | 
|  |  | 
|  | error[E0277]: the trait bound `Rc<{integer}>: DerefMut` is not satisfied | 
|  | --> $DIR/ref-mut.rs:17:9 | 
|  | | | 
|  | LL |         deref!(x) => {} | 
|  | |         ^^^^^^^^^ the trait `DerefMut` is not implemented for `Rc<{integer}>` | 
|  | | | 
|  | = note: this error originates in the macro `deref` (in Nightly builds, run with -Z macro-backtrace for more info) | 
|  |  | 
|  | error[E0277]: the trait bound `Rc<({integer},)>: DerefMut` is not satisfied | 
|  | --> $DIR/ref-mut.rs:22:9 | 
|  | | | 
|  | LL |         (x,) => {} | 
|  | |         ^^^^ the trait `DerefMut` is not implemented for `Rc<({integer},)>` | 
|  |  | 
|  | error: aborting due to 2 previous errors; 1 warning emitted | 
|  |  | 
|  | For more information about this error, try `rustc --explain E0277`. |