error: usage of ref pattern
  --> $DIR/ref_patterns.rs:8:14
   |
LL |         Some(ref opt) => {},
   |              ^^^^^^^
   |
   = help: consider using `&` for clarity instead
   = note: `-D clippy::ref-patterns` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::ref_patterns)]`

error: usage of ref pattern
  --> $DIR/ref_patterns.rs:15:9
   |
LL |     let ref y = x;
   |         ^^^^^
   |
   = help: consider using `&` for clarity instead

error: usage of ref pattern
  --> $DIR/ref_patterns.rs:19:21
   |
LL | fn use_in_parameter(ref x: i32) {}
   |                     ^^^^^
   |
   = help: consider using `&` for clarity instead

error: aborting due to 3 previous errors