error: needlessly taken reference of both operands
  --> $DIR/op_ref.rs:13:15
   |
13 |     let foo = &5 - &6;
   |               ^^^^^^^
   |
   = note: `-D op-ref` implied by `-D warnings`
help: use the values directly
   |
13 |     let foo = 5 - 6;
   |               ^   ^

error: taken reference of right operand
  --> $DIR/op_ref.rs:21:8
   |
21 |     if b < &a {
   |        ^^^^--
   |            |
   |            help: use the right value directly: `a`

error: aborting due to 2 previous errors