error: `filter(..).map(..)` can be simplified as `filter_map(..)`
  --> $DIR/manual_filter_map.rs:8:19
   |
LL |     let _ = (0..).filter(|n| to_opt(*n).is_some()).map(|a| to_opt(a).unwrap());
   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `filter_map(|a| to_opt(a))`
   |
   = note: `-D clippy::manual-filter-map` implied by `-D warnings`

error: `filter(..).map(..)` can be simplified as `filter_map(..)`
  --> $DIR/manual_filter_map.rs:11:19
   |
LL |     let _ = (0..).filter(|&n| to_opt(n).is_some()).map(|a| to_opt(a).expect("hi"));
   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `filter_map(|a| to_opt(a))`

error: `filter(..).map(..)` can be simplified as `filter_map(..)`
  --> $DIR/manual_filter_map.rs:14:19
   |
LL |     let _ = (0..).filter(|&n| to_res(n).is_ok()).map(|a| to_res(a).unwrap_or(1));
   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `filter_map(|a| to_res(a).ok())`

error: aborting due to 3 previous errors