1 error: usage of `contains_key` followed by `insert` on a `BTreeMap`
2 --> $DIR/entry_btree.rs:12:5
4 LL | / if !m.contains_key(&k) {
10 = note: `-D clippy::map-entry` implied by `-D warnings`
13 LL ~ if let std::collections::btree_map::Entry::Vacant(e) = m.entry(k) {
19 error: aborting due to previous error