clippy::result_map_unit_fn: Checks for usage of result.map(f) where f is a function or closure that returns the unit type ()

Does it matter?

Readability, this can be written more clearly with an if let statement

Code that does something simple in a complicated way. Warns by default.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

let x: Result<String, String> = do_stuff();
x.map(log_err_msg);
x.map(|msg| log_err_msg(format_msg(msg)));

Write this instead

let x: Result<String, String> = do_stuff();
if let Ok(msg) = x {
    log_err_msg(msg);
};
if let Ok(msg) = x {
    log_err_msg(format_msg(msg));
};

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

#[allow(clippy::result_map_unit_fn)]
fn my_function() { /* ... */ }

[lints.clippy]
result_map_unit_fn = "allow"

cargo clippy -- -A clippy::result-map-unit-fn

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.