error: usage of `contains_key` followed by `insert` on a `HashMap`
  --> $DIR/entry_fixable.rs:12:5
   |
LL | /     if !m.contains_key(&k) {
LL | |         m.insert(k, v);
LL | |     }
   | |_____^ help: consider using: `m.entry(k).or_insert(v);`
   |
   = note: `-D clippy::map-entry` implied by `-D warnings`

error: aborting due to previous error