map_entry does not consider `get()`

I tried this code:

        if let Some(&idx) = self.backtraces.get(&bt) {
            idx
        } else {
            let pp_info_idx = self.pp_infos.len();
            self.pp_infos.push(new());
            let old = self.backtraces.insert(bt, pp_info_idx);
            assert_eq!(old, None);
        }

I expected to see this happen: Clippy suggests using backtraces.entry(bt).or_insert_with(|| { ... }) instead.

Instead, this happened: Clippy gave no warning.

Meta

• cargo clippy -V: clippy 0.0.212 (0f6f2d6 2020-12-06)
• rustc -V: rustc 1.50.0-nightly (0f6f2d681 2020-12-06)

Start by tracing the existing map_entry lint and its handling of get() and insert() in the Clippy source, then locate related regression tests. Done means the reported Rust pattern is recognized and the test suite covers the expected suggestion without breaking existing cases.