RS.CLIPPY.MANUAL_FILTER_MAP

Using `_.filter(_).map(_)` in a way that can be written more simply as `filter_map(_)`

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: manual_filter_map. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for usage of _.filter(_).map(_) that can be written more simply as filter_map(_).

Why is this bad?

Redundant code in the filter and map operations is poor style and less performant.

Example

(0_i32..10)
    .filter(|n| n.checked_add(1).is_some())
    .map(|n| n.checked_add(1).unwrap());

Use instead:

(0_i32..10).filter_map(|n| n.checked_add(1));

Past names

filter_map