error: unused variable: `b`
  --> $DIR/issue-119383-if-let-guard.rs:6:24
   |
LL |         () if let Some(b) = Some(()) => {}
   |                        ^ help: if this is intentional, prefix it with an underscore: `_b`
   |
note: the lint level is defined here
  --> $DIR/issue-119383-if-let-guard.rs:2:9
   |
LL | #![deny(unused_variables)]
   |         ^^^^^^^^^^^^^^^^

error: aborting due to 1 previous error