error: called `map(..).flatten()` on an `Iterator` --> $DIR/map_flatten.rs:15:46 | LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id).flatten().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `filter_map` instead: `.filter_map(option_id)` | = note: `-D clippy::map-flatten` implied by `-D warnings` error: called `map(..).flatten()` on an `Iterator` --> $DIR/map_flatten.rs:16:46 | LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_ref).flatten().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `filter_map` instead: `.filter_map(option_id_ref)` error: called `map(..).flatten()` on an `Iterator` --> $DIR/map_flatten.rs:17:46 | LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_closure).flatten().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `filter_map` instead: `.filter_map(option_id_closure)` error: called `map(..).flatten()` on an `Iterator` --> $DIR/map_flatten.rs:18:46 | LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| x.checked_add(1)).flatten().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `filter_map` instead: `.filter_map(|x| x.checked_add(1))` error: called `map(..).flatten()` on an `Iterator` --> $DIR/map_flatten.rs:21:46 | LL | let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| 0..x).flatten().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try using `flat_map` instead: `.flat_map(|x| 0..x)` error: called `map(..).flatten()` on an `Option` --> $DIR/map_flatten.rs:24:39 | LL | let _: Option<_> = (Some(Some(1))).map(|x| x).flatten(); | ^^^^^^^^^^^^^^^^^^^^^ help: try using `and_then` instead: `.and_then(|x| x)` error: aborting due to 6 previous errors