|  | error: reference to `Umm` held across a suspend point, but should not be | 
|  | --> $DIR/ref.rs:18:13 | 
|  | | | 
|  | LL |         let guard = &mut self.u; | 
|  | |             ^^^^^ | 
|  | LL | | 
|  | LL |         other().await; | 
|  | |                 ----- the value is held across this suspend point | 
|  | | | 
|  | note: You gotta use Umm's, ya know? | 
|  | --> $DIR/ref.rs:18:13 | 
|  | | | 
|  | LL |         let guard = &mut self.u; | 
|  | |             ^^^^^ | 
|  | help: consider using a block (`{ ... }`) to shrink the value's scope, ending before the suspend point | 
|  | --> $DIR/ref.rs:18:13 | 
|  | | | 
|  | LL |         let guard = &mut self.u; | 
|  | |             ^^^^^ | 
|  | note: the lint level is defined here | 
|  | --> $DIR/ref.rs:3:9 | 
|  | | | 
|  | LL | #![deny(must_not_suspend)] | 
|  | |         ^^^^^^^^^^^^^^^^ | 
|  |  | 
|  | error: aborting due to 1 previous error | 
|  |  |