error[E0382]: use of moved value: `b`
  --> $DIR/issue-27282-move-match-input-into-guard.rs:16:14
   |
LL |     let b = &mut true;
   |         - move occurs because `b` has type `&mut bool`, which does not implement the `Copy` trait
...
LL |         _ if { (|| { let bar = b; *bar = false; })();
   |                 --             - variable moved due to use in closure
   |                 |
   |                 value moved into closure here
LL |                      false } => { },
LL |         &mut true => { println!("You might think we should get here"); },
   |              ^^^^ value used here after move

error: aborting due to previous error

For more information about this error, try `rustc --explain E0382`.